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The Streak-Tube Imaging Lidar (STIL) has been widely used in high-precision measurement systems due to its ability to capture detailed spatial and temporal information. In this paper, we proposed a ranging measurement method that integrates a Time-to-Digital Converter (TDC) with a streak camera in a remote STIL system. In this method, the TDC accurately measures the trigger pulse time, while the streak camera captures high time-resolution images of the laser echo, thereby enhancing both measurement accuracy and range. A corresponding ranging model is developed for this method. To validate the system's performance, an outdoor experiment covering a distance of up to 6 km was conducted. The results demonstrate that the system achieved a distance measurement accuracy of 0.1 m, highlighting its effectiveness in long-range applications. The experiment further confirms that the combination of STIL and TDC significantly enhances accuracy and range, making it suitable for various long-range, high-precision measurement tasks. [ABSTRACT FROM AUTHOR]

Thiamine Deficiency Complex is an emerging health concern for California’s Chinook salmon (Oncorhynchus tshawytscha). Low egg thiamine concentrations contribute to the condition being expressed in newly hatched fry leading to increased rates of early mortality. Increased rates of mortality in early life stages could further jeopardize already depleted populations of Chinook salmon in California’s river systems. In 2020, a study of egg thiamine concentrations at Coleman National Fish Hatchery and Livingston Stone Fish Hatchery revealed nearly 50% of the sampled populations contained egg thiamine concentrations below 5 nmol/g which is the egg thiamine concentration threshold for 95% fry viability. This study assesses egg thiamine concentrations from Chinook salmon sampled in the Klamath River Basin during their 2020 and 2021 annual spawning migrations. The study will also assess relationships between egg thiamine concentration and other variables including water temperature and distance of migration, and it will also evaluate relationships between egg diameter and egg thiamine concentration.See the media created for this project here: https://storymaps.arcgis.com/stories/b49ec1acfdc9435dabeeca0c2606eda1

Perturbation of thyroid hormone (T4) synthesis is known to cause numerous developmental, metabolic, and cognitive disorders in humans. Due to species differences in sensitivity to chemical exposures, there is a need for human-based in vitro approaches that recapitulate thyroid cellular architecture and T4 production when screening. To address these limitations, primary human thyrocytes, isolated from healthy adult donor tissues and cryopreserved at passage one (p’1) were characterized for cellular composition, 3D follicular architecture, and thyroglobulin (TG)/T4 expression and inhibition by prototype thyroid disrupting chemicals (TDC). Flow analysis of the post-thaw cell suspension showed >80% EpCAM-positive cells with 10%–50% CD90-positive cells. When seeded onto 96-well Matrigel® -coated plates and treated with bovine thyroid stimulating hormone (TSH), thyrocytes formed 3D microtissues during the initial 4–5 days of culture. The microtissues exhibited a stable morphology and size over a 14-day culture period. TG and T4 production were highest in microtissues when the proportion of CD90-positive cells, seeding density and thyroid stimulating hormone concentrations were between 10%–30%, 6K–12K cells per well, and 0.03–1 mIU/mL, respectively. At maximal TG and T4 production levels, average microtissue diameters ranged between 50 and 200 µm. The T4 IC50 values for two prototype TPO inhibitors, 6-propyl-2-thiouracil and methimazole, were ~0.7 µM and ~0.5 µM, respectively, in microtissue cultures treated between days 9 and 14. Overall, p’1 cryopreserved primary human thyrocytes in 3D microtissue culture represent a promising new model system to prioritize potential TDC acting directly on the thyroid as part of a weight-of-evidence hazard characterization. [ABSTRACT FROM AUTHOR]

Background: Our goal was to investigate linkages between skin color parameters and skin hydration. Since most prior studies focused on stratum corneum hydration, we focused on epidermal and dermal hydration in relation to skin color parameters in both sexes. Materials and Methods: Thirty adults (16 female) with an age ± SD of 24.3 ± 0.6 years participated. Three sites on both volar forearms were evaluated for melanin index (MI), erythema index (EI), Individual Typology Angle (ITA), tissue dielectric constant (TDC) values to depths of 0.5 mm (TDC0.5) and 2.5 mm (TDC2.5), and Fitzpatrick skin type (FST). Results: MI and EI were highly correlated (r = 0.800, p < 0.001) with maximum differences in MI and ITA along the arm of 3% and 6.3% with no difference between arms. Male MI was greater than females (p < 0.01). Male TDC2.5 was 36.1 ± 5.4 and correlated with EI (r = 0.231, p = 0.035). Contrastingly, female TDC25 was 28.5 ± 3.6 with no correlation with EI but was correlated with MI (r = −0.301, p = 0.003). These differential patterns held true for TDC0.5. For both sexes, FST and ITA were highly correlated (r = −0.756, p < 0.001). Conclusions: The findings revealed several correlations between skin color parameters and hydration that differed between males in females in some cases. The observed correlations may indicate that melanin may differentially impact water‐holding capacity between sexes and provides a future research target. Further, these initial findings also may hold significance for dermatological assessments and the customization of skincare treatments tailored to individual skin types and demographics. [ABSTRACT FROM AUTHOR]

The resolution of time-to-digital converters (TDC) is one parameter that will define its efficiency. This research demonstrates a 5.4 ps TDC with anti-PVT-variation implemented in 90-nm CMOS technology. The proposed converter uses a two-step architecture. The first stage is a Buffer Delay Line (BDL) to acquire a wide dynamic range characteristic. The second stage that will provide a higher resolution is Vernier delay line which receives the start and stop signals from the edge detector. A PVT (process, voltage, temperature) corner detector is equipped in the proposed TDC to resist the PVT variation. The proposed TDC's post-layout simulation results achieve a delay variation of 2 ps and a resolution of 5.4 ps, and an acceptable dynamic range of 890 ps. The INL and DNL attained a value of 0.8 and −1 LSB from the simulations. The proposed TDC attains the best FOM based on post-layout simulations with a value of 0.177, which makes it superior to all prior designs. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Investigación e Innovación en Ciencias de la Salud (RIICS) is the property of Fundacion Universitaria Maria Cano and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The firmware developed for the readout and trigger processing of the information emerging from the BIS78-RPC Muon Spectrometer chambers in the ATLAS experiment at CERN is presented here, together with data processing techniques, data acquisition software, and tests of the readout chain system, which represent efforts to make these chambers operational in the ATLAS experiment. This work is performed in the context of the BIS78-RPC project, which deals with the pilot deployment of a new generation of sMDT+RPCs in the experiment. Such chambers are planned to be fully deployed in the whole barrel inner layer of the Muon Spectrometer during the Phase II upgrade of the ATLAS experiment. On-chamber front-ends include an amplifier, a discriminator ASIC, and an LVDS transmitter. The signal is digitized by CERN HPTDC chips and then processed by an FPGA, which is the heart of the readout and trigger processing, using various techniques. [ABSTRACT FROM AUTHOR]

Melatonin is a crucial regulator of plant growth and development as well as stress tolerance. However, we only have a limited understanding of the functions of endogenous melatonin. Tryptophan decarboxylase (TDC) serves as the initial rate-limiting enzyme in the melatonin synthesis pathway. To date, no cucumber TDC gene has been cloned and characterized. In this study, we identified two TDC genes (CsTDC1 and CsTDC2) in the cucumber genome. The subcellular localization analysis indicated that CsTDC1 and CsTDC2 are predominantly localized in the cytoplasm and plasma membrane. Tissue-specific expression analyses revealed that CsTDC1 and CsTDC2 are expressed in both vegetative and reproductive organs. Many cis-elements related to stress, hormone, and light responses as well as development were identified in the CsTDC promoter regions. Furthermore, the expression of CsTDC1 and CsTDC2 was strongly induced by treatments with various abiotic stresses and exogenous hormones. The transient overexpression of CsTDC1 and CsTDC2 in tobacco leaves resulted in increases in the TDC activity and melatonin content, along with improved tolerance of tobacco leaves to salt, drought, and low-temperature stresses. Notably, the overexpression of CsTDC2 had a more pronounced effect than the overexpression of CsTDC1. Accordingly, both CsTDC genes, but especially CsTDC2, may be important for regulating cucumber growth, development, and stress tolerance. The study findings provide a theoretical and experimental basis for future functional analyses of endogenous melatonin in cucumber. [ABSTRACT FROM AUTHOR]

Background: Globally, esophageal squamous cell carcinoma (ESCC) stands out as a common cancer type, characterized by its notably high rates of occurrence and mortality. Recent advancements in treatment methods, including immunotherapy, have shown promise, yet the prognosis remains poor. In the context of tumor development and treatment outcomes, the tumor microenvironment (TME), especially the function of dendritic cells (DCs), is significantly influential. Our study aims to delve deeper into the heterogeneity of DCs in ESCC using single-cell RNA sequencing (scRNA-seq) and bulk RNA analysis. Methods: In the scRNA-seq analysis, we utilized the SCP package for result visualization and functional enrichment analysis of cell subpopulations. CellChat was employed to identify potential oncogenic mechanisms in DCs, while Monocle 2 traced the evolutionary trajectory of the three DC subtypes. CopyKAT assessed the benign or malignant nature of cells, and SCENIC conducted transcription factor regulatory network analysis, offering a preliminary exploration of DC heterogeneity. In Bulk-RNA analysis, we constructed a prognostic model for ESCC prognosis and immunotherapy response, based on DC marker genes. This model was validated through quantitative PCR (qPCR) and immunohistochemistry (IHC), confirming the gene expression levels. Results: In this study, through intercellular communication analysis, we identified GALECTIN and MHC-I signaling pathways as potential oncogenic mechanisms within dendritic cells. We categorized DCs into three subtypes: plasmacytoid (pDC), conventional (cDC), and tolerogenic (tDC). Our findings revealed that pDCs exhibited an increased proportion of cells in the G2/M and S phases, indicating enhanced cellular activity. Pseudotime trajectory analysis demonstrated that cDCs were in early stages of differentiation, whereas tDCs were in more advanced stages, with pDCs distributed across both early and late differentiation phases. Prognostic analysis highlighted a significant correlation between pDCs and tDCs with the prognosis of ESCC (P< 0.05), while no significant correlation was observed between cDCs and ESCC prognosis (P = 0.31). The analysis of cell malignancy showed the lowest proportion of malignant cells in cDCs (17%), followed by pDCs (29%), and the highest in tDCs (48%), with these results being statistically significant (P< 0.05). We developed a robust ESCC prognostic model based on marker genes of pDCs and tDCs in the GSE53624 cohort (n = 119), which was validated in the TCGA-ESCC cohort (n = 139) and the IMvigor210 immunotherapy cohort (n = 298) (P< 0.05). Additionally, we supplemented the study with a novel nomogram that integrates clinical features and risk assessments. Finally, the expression levels of genes involved in the model were validated using qPCR (n = 8) and IHC (n = 16), thereby confirming the accuracy of our analysis. Conclusion: This study enhances the understanding of dendritic cell heterogeneity in ESCC and its impact on patient prognosis. The insights gained from scRNA-seq and Bulk-RNA analysis contribute to the development of novel biomarkers and therapeutic targets. Our prognostic models based on DC-related gene signatures hold promise for improving ESCC patient stratification and guiding treatment decisions. [ABSTRACT FROM AUTHOR]

Perturbation of thyroid hormone (T4) synthesis is known to cause numerous developmental, metabolic, and cognitive disorders in humans. Due to species differences in sensitivity to chemical exposures, there is a need for human-based in vitro approaches that recapitulate thyroid cellular architecture and T4 production when screening. To address these limitations, primary human thyrocytes, isolated from healthy adult donor tissues and cryopreserved at passage one (p’1) were characterized for cellular composition, 3D follicular architecture, and thyroglobulin (TG)/T4 expression and inhibition by prototype thyroid disrupting chemicals (TDC). Flow analysis of the post-thaw cell suspension showed >80% EpCAM-positive cells with 10%–50% CD90-positive cells. When seeded onto 96-well Matrigel®-coated plates and treated with bovine thyroid stimulating hormone (TSH), thyrocytes formed 3D microtissues during the initial 4–5 days of culture. The microtissues exhibited a stable morphology and size over a 14-day culture period. TG and T4 production were highest in microtissues when the proportion of CD90-positive cells, seeding density and thyroid stimulating hormone concentrations were between 10%–30%, 6K–12K cells per well, and 0.03–1 mIU/mL, respectively. At maximal TG and T4 production levels, average microtissue diameters ranged between 50 and 200 µm. The T4 IC50 values for two prototype TPO inhibitors, 6-propyl-2-thiouracil and methimazole, were ∼0.7 µM and ∼0.5 µM, respectively, in microtissue cultures treated between days 9 and 14. Overall, p’1 cryopreserved primary human thyrocytes in 3D microtissue culture represent a promising new model system to prioritize potential TDC acting directly on the thyroid as part of a weight-of-evidence hazard characterization.

The Streak-Tube Imaging Lidar (STIL) has been widely used in high-precision measurement systems due to its ability to capture detailed spatial and temporal information. In this paper, we proposed a ranging measurement method that integrates a Time-to-Digital Converter (TDC) with a streak camera in a remote STIL system. In this method, the TDC accurately measures the trigger pulse time, while the streak camera captures high time-resolution images of the laser echo, thereby enhancing both measurement accuracy and range. A corresponding ranging model is developed for this method. To validate the system’s performance, an outdoor experiment covering a distance of up to 6 km was conducted. The results demonstrate that the system achieved a distance measurement accuracy of 0.1 m, highlighting its effectiveness in long-range applications. The experiment further confirms that the combination of STIL and TDC significantly enhances accuracy and range, making it suitable for various long-range, high-precision measurement tasks.

Le trouble développemental de la coordination (TDC) s'expliquerait par un défaut du couplage perception-action (CPA) antérieur au trouble de la motricité intentionnelle, perturbant ainsi les représentations internes dont le schéma corporel. L'étude postulait qu'un entraînement du CPA avec des exercices de dissociation motrice, aiderait les enfants ayant un TDC à développer implicitement leur schéma corporel (c.-à-d., une intervention axée sur les fonctions ayant une approche bottom-up), observable à travers les habiletés motrices, les fonctions spatiales et la perception de soi. Une intervention à distance a été proposée à 13 enfants, âgés de 7 à 10 ans, ayant un TDC. Deux fois par semaine, durant 8 semaines, ils devaient visionner des séances vidéo comportant chacune un exercice d'adaptation du réglage temporel d'un patron moteur, un exercice de succession de positions segmentaires ou de combinaison de mouvements distincts en simultané, et un exercice de stabilisation d'objet sur soi durant un enchaînement postural. La pratique des dissociations motrices dans les exercices a permis aux enfants d'améliorer significativement leurs habiletés motrices (p. ex., l'équilibre, le saut, la coordination, la rapidité et précision manuelle), leurs fonctions spatiales (p. ex., la rotation mentale et les praxies visuo-constructives) et leur perception d'eux-mêmes (p. ex., l'apparence physique perçue) avec des tailles d'effet allant de modéré à élevé : min. : d = 0,549 et p = 0,048 ; max. : d = 0,883 et p = 0,001. Les résultats suggèrent que l'entraînement du CPA précise les représentations sensorimotrices avec des effets de transfert sur les habiletés motrices, les fonctions spatiales et la perception de soi. De futures études devront confirmer cette interprétation. En résumé, l'étude montre l'efficacité d'une intervention à distance dans la réadaptation, valide l'approche bottom-up et souligne l'importance de soutenir les enfants ayant un TDC dans le développement de leur schéma corporel. Developmental coordination disorder (DCD) is explained by a defect of the perception-action coupling (PAC) prior to the intentional motor disorder, thus disrupting internal representations including the body schema. The study postulated that training the PAC through motor dissociation exercises would help children with DCD to implicitly develop their body schema (i.e., a function-oriented intervention with a bottom-up approach), observable through motor skills, spatial functions and self-perception. A remote intervention was proposed to 13 children, aged 7 to 10 years, with DCD. Twice a week, for eight weeks, they watched video sessions each composed of an exercise of adaptation of the temporal adjustment of a motor pattern, an exercise of succession of segmental positions or of combination of distinct simultaneous movements, and an exercise of stabilization of an object on oneself during a postural sequence. The practice of motor dissociations in the exercises allowed the children to significantly improve their motor skills (e.g., balance, jumping, coordination, manual speed and precision), spatial functions (e.g., mental rotation and visuo-constructive praxis) and self-perception (e.g., perceived physical appearance) with effect sizes ranging from moderate to high: min.: d = 0.549 and P = 0.048; max.: d = 0.883 and P = 0.001. The results suggest that PAC training refines sensorimotor representations with transfer effects on motor skills, spatial functions and self-perception. Future studies should confirm this interpretation. In summary, the study shows the effectiveness of a remote intervention in rehabilitation, validates the bottom-up approach, and underlines the importance of supporting children with DCD in the development of their body schema. [ABSTRACT FROM AUTHOR]

TDC are hematopoietic cells that combine dendritic cell (DC) and conventional T‐cell markers and functional properties. They were identified in secondary lymphoid organs (SLOs) of naïve mice as cells expressing CD11c, major histocompatibility molecules (MHC)‐II, and the T‐cell receptor (TCR). Despite thorough characterization, a physiological role for TDC remains to be determined. Unfortunately, using CD11c as a marker for TDC has the caveat of its upregulation on different cells, including T cells, upon activation. Here, we took advantage of Zbtb46‐GFP reporter mice to explore the frequency and localization of TDC in different tissues at steady state and upon viral infection. RNA sequencing analysis confirmed that TDC sorted from Zbtb46‐GFP mice have a gene signature that is distinct from conventional T cells and DC. In addition, this reporter model allowed for identification of TDC in situ not only in SLOs but also in the liver and lung of naïve mice. Interestingly, we found that TDC numbers in the SLOs increased upon viral infection, suggesting that TDC might play a role during viral infections. In conclusion, we propose a visualization strategy that might shed light on the physiological role of TDC in several pathological contexts, including infection and cancer. [ABSTRACT FROM AUTHOR]

We report the case of a near fatal arterial injury in a patient undergoing an inside-out catheter placement through an occluded central venous system using the Surfacer device (Bluegrass Vascular). The right internal mammary artery was inadvertently lacerated during the procedure, leading to cardiovascular collapse. The patient was rescued by transfusion, placement of a chest tube, and coil embolization of the right internal mammary artery. Postprocedure analysis of intraoperative cone beam computed tomography revealed that this injury was predictable on imaging, underscoring the need for advanced imaging guidance to enhance the safety of this procedure.

A variable-gain time-to-digital converter (TDC)-based multiplying delay-locked loop (MDLL) clock multiplier featuring fast-locking and programmable N/M-ratio frequency multiplication capability is presented in this paper. The proposed all-digital programmable N/M-ratio MDLL achieves fast-locking capability by adopting a new variable-gain TDC. In conventional fixed-gain TDC-based MDLLs, the lock time increases as the value of the multiplication factor N decreases. However, the proposed variable-gain TDC can minimize the MDLL lock time by adjusting the TDC gain according to the change in N value. Implemented in a 40 nm 1.1-V CMOS process, the proposed all-digital MDLL clock multiplier generates output clock frequencies ranging from 0.65 to 3.2 GHz, with programmable N/M ratios of N = 5 to 16 and M = 1 to 8. It achieves a fast lock time of only 3 × M (=9) reference clock cycles when N/M = 10/3 at 2.0 GHz and demonstrates a simulated peak-to-peak jitter of 3.16 ps at 3.2 GHz when N/M = 16/3. Additionally, it occupies an active area of only 0.02 mm2 (=200 μm × 100 μm) and consumes a power of 2.3 mW at 1.0 GHz. [ABSTRACT FROM AUTHOR]

Hafnium-based ferroelectric memories are a promising approach to enhancing integrated circuit performance, offering advantages such as miniaturization, compatibility with CMOS technology, fast read and write speeds, non-volatility, and low power consumption. However, FeRAM (Ferroelectric Random Access Memory) still faces challenges related to endurance and retention susceptibility to process variations. Hence, testing and obtaining the core parameters of ferroelectric capacitors continuously is essential to investigate these phenomena and explore the potential solution. The traditional method for measuring ferroelectric capacitors has limitations in timing generation capability, introduces parasitic capacitance, and lacks accuracy for small-area capacitors. In this study, we analyzed the working principle of ferroelectric capacitors and designed a method to detect the remnant polarization, saturation polarization, and imprint offset of ferroelectric capacitors. Further, we further proposed a circuit implementation method. The proposed test circuit conquers these limitations and enables high-precision testing of ferroelectric capacitors, contributing to developing hafnium-based ferroelectric memories. The circuit includes a flip-readout circuit, a capacitance calibration circuit, and a voltage-to-time converter and time-to-digital converter (VTC&TDC) readout circuit. According to simulation results, the capacitance calibration circuit reduces the deviation of the capacitance by 84%, and the accuracy of the readout circuit is 5.91 bits, with a readout time of 150 ns and a power consumption of 1 mW. This circuit enables low-cost acquisition of array-level small-area ferroelectric capacitance data, which can guide subsequent device optimization and circuit design. [ABSTRACT FROM AUTHOR]

This paper presents a test methodology to facilitate the measuring processes of LiDAR receiver ICs by avoiding the inherent walk error issue. In a typical LiDAR system, a costly laser diode driver emits narrow light pulses with fast rising edges, and the reflected pulses from targets enter an optical detector followed by an analog front-end (AFE) circuit. Then, the received signals pass through the cascaded amplifiers down to the time-to-digital converter (TDC) that can estimate the detection range. However, this relatively long signal journey leads to the significant decline of rising-edge slopes and the output pulse spreading, thus producing inherent walk errors in LiDAR receiver ICs. Compensation methods requiring complex algorithms and extra chip area have frequently been exploited to lessen the walk errors. In this paper, however, a simpler and lower-cost methodology is proposed to test LiDAR receiver ICs by employing a high-speed buffer and variable delay cells right before the TDC. With these circuits, both START and STOP pulses show very similar pulse shapes, thus effectively avoiding the walk error issue. Additionally, the time interval between two pulses is easily determined by varying the number of the delay cells. Test chips of the proposed receiver IC implemented in a 180-nm CMOS process successfully demonstrate easier and more accurate measurement results. [ABSTRACT FROM AUTHOR]

Melatonin is a crucial regulator of plant growth and development as well as stress tolerance. However, we only have a limited understanding of the functions of endogenous melatonin. Tryptophan decarboxylase (TDC) serves as the initial rate-limiting enzyme in the melatonin synthesis pathway. To date, no cucumber TDC gene has been cloned and characterized. In this study, we identified two TDC genes (CsTDC1 and CsTDC2) in the cucumber genome. The subcellular localization analysis indicated that CsTDC1 and CsTDC2 are predominantly localized in the cytoplasm and plasma membrane. Tissue-specific expression analyses revealed that CsTDC1 and CsTDC2 are expressed in both vegetative and reproductive organs. Many cis-elements related to stress, hormone, and light responses as well as development were identified in the CsTDC promoter regions. Furthermore, the expression of CsTDC1 and CsTDC2 was strongly induced by treatments with various abiotic stresses and exogenous hormones. The transient overexpression of CsTDC1 and CsTDC2 in tobacco leaves resulted in increases in the TDC activity and melatonin content, along with improved tolerance of tobacco leaves to salt, drought, and low-temperature stresses. Notably, the overexpression of CsTDC2 had a more pronounced effect than the overexpression of CsTDC1. Accordingly, both CsTDC genes, but especially CsTDC2, may be important for regulating cucumber growth, development, and stress tolerance. The study findings provide a theoretical and experimental basis for future functional analyses of endogenous melatonin in cucumber.

This work presents a Time-to-Digital Converter implemented using two nested Johnson counters and suitable for time-lapse measurement applications. The proposed structure is composed of two 4-bit nested counters, two digital-logic control networks, two registers and a single decoder. Semi-dynamic logic was used for the decoder to reduce its power consumption. The system has a standard digital output and is powered by a 1.8 V supply with a total power consumption of 32.4 mW. A prototype was fabricated using a TSMC 180 nm CMOS technology. The proposed structure uses a 508 µm x 225 µm area. In addition, this TDC has a standard deviation of 0.78 LSB with a fixed input time interval operating at a frequency of 1 MHz. The proposed structure shows good performance results and repeatability for continuous conversion conditions, these results are attributed to the simplicity of the system and the use of counters with minimum gate delay as the main elements for the TDC.

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents an 8-bit time-domain analog-to-digital converter (ADC) achieving ten-GS/s conversion speed with only two time-interleaved (TI) channels. A successive approximation register (SAR) time-to-digital converter (TDC) is implemented for the subpicosecond resolution time quantization with high power/area efficiency and low jitter. The throughput of the SAR TDC is enhanced by a unique delay-tracking pipelining technique to enable a 5-GS/s single-channel conversion. On the circuit level, the reference time generation for the SAR TDC is realized by the proposed selective delay tuning (SDT) cell for high efficiency and small reference time variation. Fabricated in the 14-nm FinFet CMOS technology, this ADC achieves a 37.2-dB signal-to-noise and distortion ratio (SNDR) and a 50.6-dB spurious-free dynamic range (SFDR) at the Nyquist input frequency, leading to a 24.8-fJ/conv-step Walden figure of merit with an active area of only 2850 $\mu \text{m}^{2}$. [ABSTRACT FROM AUTHOR]

A novel two-step coarse-fine time-to-digital converter (TDC) is fabricated in 65-nm CMOS, with a relaxation oscillator based peak counter (ROC) for the coarse stage and a successive approximation analog-to-digital converter (SAR-ADC) for the fine stage. A reconfigurable 3-bit digital counter expands the dynamic range, and a high-precision 9-bit SAR-ADC ensures the resolution. The proposed ROC-ADC scheme conducts the time residence and the transfer linearity well for two-step quantization. Experimental results show that the presented 12-bit TDC achieves a high resolution less than 8 ps and a wide dynamic range up to 30 ns, with the differential nonlinearity (DNL) and integral nonlinearity (INL) values of 0.92 LSB and 1.07 LSB, respectively. The TDC consumes a low power of 0.6 mW from a 1-V supply, with the active area of 0.14 mm2. [ABSTRACT FROM AUTHOR]

In this work, we present a compact "adaptive downsampling" method that mitigates the nonlinearity problems associated with FPGA-based TDCs that utilize delay lines. Additionally, this generic method allows for trade-offs between resolution, linearity, and resource utilization. Since nonlinearity is one of the predominant issues regarding delay lines in FPGA-based TDCs, combined with the fact that delay lines are utilized for a wide range of TDC architectures (not limited to the delay-line TDC), other implementations (e.g., Vernier or wave union TDCs), also in different FPGA devices, can directly benefit from the proposed adaptive method, with no need for either custom routing or complex tuning of the converter. Furthermore, implementation-related challenges regarding clock skew, measurement uncertainty, and the placement of the TDC are discussed and we also propose an experimental setup that utilizes only FPGA resources in order to characterize the converter. Although the TDC in this work was implemented in a Xilinx Virtex-6 device and was characterized under different operational modes, we successfully optimized the converter's nonlinearity and resource utilization while retaining single-shot precision. The best performing (in terms of linearity) implementation reached D N L r m s and I N L r m s values of 0.30 LSB and 0.45 LSB, respectively, and the single-shot precision (σ) was 9.0 ps. [ABSTRACT FROM AUTHOR]

Background: Skin water measurements are used to investigate skin physiology, clinically study dermatological issues, and for conditions like diabetes, oedema, and lymphedema with measurements done at various times of day (TOD). One method used is skin's tissue dielectric constant (TDC), often clinically measured to a single depth of 2.5 mm. This report characterizes intraday variations measured to multiple depths to guide expected TOD and depth dependence., Materials and Methods: Twelve medical students self-measured TDC on their forearm to depths of 0.5, 1.5, 2.5, and 5.0 mm every 2 h from 08:00 to 24:00 h on 2 consecutive days. All were trained in the procedure., Results: TDC declined slightly from morning through evening, mostly at 0.5 mm for which TDC was reduced by 4%. TDC values were not related to participants' whole-body fat or water percentages. The TDC decrease was less at 1.5 mm where the reduction was 2.7%. At depths of 2.5 or 5.0 mm, there was no significant decrease in TOD., Conclusion: Skin TDC shows a minor decreasing trend with an effect greater for shallower depths. In part, the clinical relevance of the findings relates to the confidence level associated with skin water estimates, based on TDC measurements, when measured at different TOD and depths during normal clinic hours. Based on the present data the TOD change is at most 4% and insignificant for measurement depths of 2.5 mm., (© 2024 Scandinavian Society of Clinical Physiology and Nuclear Medicine.)

Background: This study aimed to investigate, characterize, and provide quantitative reference data on tissue dielectric constant (TDC) values of female breasts when measurements were made to 5 mm depths and determine the utility of these measurements to differentiate between benign and malignant breast tumors. Methods and Results: Breast TDC was measured bilaterally in 82 women just prior to an ultrasound-guided diagnostic biopsy of one tumor in one breast. TDC was measured in triplicate over the tumor and the contralateral healthy breast. Considering all paired breasts, the average TDC (mean ± SD) for healthy breasts was less than for tumor-bearing breasts (26.7 ± 4.5 vs. 29.9 ± 8.5, p = 0.0003). Conclusions: Breast TDC values measured to 5 mm in 82 healthy nonedematous breasts provide a two-SD threshold reference value of 35.7. This represents a TDC value above which the presence of breast edema/lymphedema may be indicated based on the two-SD threshold criterion. For unilateral cases, an interbreast TDC ratio exceeding 1.275 may be considered a breast edema/lymphedema indicator also based on the two SD criteria used. These thresholds may have utility for early detection and to track breast edema/lymphedema changes. A comparison of these TDC values obtained from benign versus malignant tumors indicates no statistically significant difference between them. However, interbreast TDC ratios were statistically higher for breasts with malignant versus benign tumors. However, the large overlap of the ratio values renders this method of discrimination between benign vs. malignant tumors inadequate based on the present findings.

An all-digital clock frequency multiplier that achieves excellent locking time for an energy-efficient chiplet-based system-on-chip (SoC) design is presented. The proposed architecture is based on an all-digital multiplying delay-locked loop (MDLL) to provide fast locking time and multiplied output clock frequency. The proposed MDLL has two operation modes: TDC tracking and sequential tracking. At the beginning of the operation, the MDLL utilizes a cyclic Vernier time-to-digital converter (TDC) to detect the initial phase error between the reference clock and the output clock. Then the TDC generates a digital code word (DCW) for controlling the digitally controlled oscillator (DCO) to achieve a fast lock time. The gains of TDC and DCO are designed to match well with each other, enabling phase and frequency locking in only two searches in the TDC tracking mode. After locking, the TDC is turned off, and the MDLL performs the sequential tracking mode and minimizes jitter by using the delta-sigma modulator (DSM)-based dithering jitter reduction scheme. The prototype all-digital MDLL is fabricated in a 40-nm CMOS process and achieves a fast lock time of less than six reference clock cycles at 1.6 GHz from a 100 MHz reference clock. Even when the 100 MHz reference clock has a relatively high RMS jitter of 2.19 ps (peak-to-peak jitter = 15.74 ps), the measured RMS and peak-to-peak jitter values of the 1.6 GHz MDLL output clock are only 2.75 ps and 23.01 ps, respectively. The proposed all-digital MDLL occupies an active area of only 0.024 mm2 and dissipates 3.56 mW at 1.6 GHz.

Global warming has multifarious adverse effects on plant growth and productivity. Nonetheless, the effects of endogenous phytomelatonin on the high‐temperature resistance of plants and the underlying genetic mechanisms remain unclear. Here, herbaceous peony (Paeonia lactiflora Pall.) tryptophan decarboxylase (TDC) gene involved in phytomelatonin biosynthesis was shown to respond to high‐temperature stress at the transcriptional level, and its transcript level was positively correlated with phytomelatonin production. Moreover, overexpression of PlTDC enhanced phytomelatonin production and high‐temperature stress tolerance in transgenic tobacco, while silencing PlTDC expression decreased these parameters in P. lactiflora. In addition, a 2402 bp promoter fragment of PlTDC was isolated, and DNA pull‐down assay revealed that one APETALA2/ethylene‐responsive element‐binding factor (AP2/ERF) transcription factor, PlTOE3, could specifically activate the PlTDC promoter, which was further verified by yeast one‐hybrid assay and luciferase reporter assay. PlTOE3 was a nucleus‐localized protein, and its transcript level responded to high‐temperature stress. Additionally, transgenic tobacco overexpressing PlTOE3 showed enhanced phytomelatonin production and high‐temperature stress tolerance, while silencing PlTDC expression obtained the opposite results. These results illustrated that PlTOE3 bound the PlTDC promoter to enhance high‐temperature stress tolerance by increasing phytomelatonin production in P. lactiflora. This study is to elucidate the effects of endogenous phytomelatonin on the high‐temperature resistance of plants, and the results illustrated that PlTOE3 bound the PlTDC promoter to enhance high‐temperature stress tolerance by increasing phytomelatonin production in herbaceous peony. [ABSTRACT FROM AUTHOR]

A 13-bit Time to Digital Converter is implemented using multiphase clock technique. Xilinx's Virtex 5 FPGA platform is used to realize the TDC architecture. One PLL within the FPGA works as a clock synthesizer to multiply the reference clock to 500 MHz. Then the combination of PLL and DLL topologies are used to generate 16 phases of the clock, separated by 11.25°. Further, 16 phases are generated by inverting the first 16 phases. A resolution of 62.5 ps has been recorded. Measured INL and DNL are within 1 LSB. The present work is suitable for many critical applications due to its PVT insensitive and robust properties. [ABSTRACT FROM AUTHOR]

With the Online Emergency Remote Teaching (OERT) practices emerged during the outbreak of the pandemic, teachers’ digital competence (TDC) has gained growing attention in educational ICT research realm. In view of this context, the present review study aimed at illuminating the current state of TDCs literature by identifying the volume, growth trajectory, geographical distribution of TDC research. It also aimed at mapping highly influential TDC scholars, documents, and journals. Retrieved from the educational research category in the Clarivate Analytics Web of Science (WoS) core collection database, the metadata of 406 articles were analyzed by employing bibliometric performance and science mapping techniques in VOSwiever 1.6. The timeframe for the study was the last two decades (from 2002 to 2021). Findings illustrated that there has been a growing increase in the number of studies focusing on TDCs. This increase is more evident in the Covid-19 pandemic period, particularly in the last two years. More specifically, more than half of all studies were published in the years 2020 and 2021. Findings also illustrated that there is a dominance of Spanish scholars and organizations in TDC research since 2 out of every 3 studies were carried out by researchers affiliated to Spanish Universities. Additionally, co-citation analysis purported the intellectual structure of TDC knowledge base by identifying the most influential authors and documents. Finally, co-occurrence analysis revealed the concept analysis topical foci of TDC research. These topics are concentrated on “teachers’ digital competence”, “higher education studies”, teacher training programs”, and “ICT in education”. As a result, based on the findings of the study some recommendations were proposed that will contribute into the ICT research community by reflecting the intellectual structure of existing TDC research, thus highlighting the future research direction.

Even after almost three decades of introducing competitiveness into the tourism sector, there is still a rising trend in literature on Tourism Destination Competitiveness (TDC). Though there are a few systematic and traditional reviews in the domain, there has been no study of the bibliometric variables. In the current study, scientific literature on the topic is mapped through evaluative and relational bibliometric techniques utilizing Web of Science (161 documents) and Scopus (manually selected five documents) databases to run a bibliometric analysis of 166 documents on TDC, uncovering the domain's research trend concerning authors, sources, and publications. The science mapping tool bibliometrix R-package biblioshiny and VOSviewer are used to analyze the trend of scientific publications in the area, untapped knowledge, possible future trends, and implications. The analysis is undertaken on three levels: source, author, and document, as well as three types of knowledge structures: conceptual, intellectual, and social. The bibliometric analysis consists of a descriptive evaluation of the bibliographic data frame, network analyses, and graphical visualization. As per the analysis, the competitiveness of natural/cultural destinations is rarely assessed in the global scenario. The maximum number of studies in the domain are carried out in European countries. The findings can guide researchers to focus on less developed themes/areas. [ABSTRACT FROM AUTHOR]

With the development of artificial intelligence, LiDAR finds significant applications in robotics and autonomous driving. Aiming at increasing the compactness and the integration of 2-D LiDAR, this paper presents a highly digitally integrated 2-D LiDAR system implemented in a low-cost FPGA. The system is made of off-the-shelf components to limit the cost to USD 100. A laser transceiver with a symmetrical transmitting and receiving lens emits and collects laser pulses to range distance using the time-of-flight (ToF) method. As a key component in ToF, the FPGA-based time-to-digital converter (TDC) is adopted for counting the round-trip time of pulses, which is implemented in a low-cost FPGA of ZYNQ7010 with limited resources. The symmetrical structure of the delay line is used to design a more efficient TDC. The FPGA-TDC enables flexibility of design and integration with more functional logics and is microcontroller-free. All the digital logics including data processing and controlling are integrated into an FPGA with the TDC logics to realize fully digital integration and compact dimensions. The utilization of the whole architecture in the FPGA is about 15%. The experimental results demonstrated that the ranging accuracy of the LiDAR is about 2 cm, which is suitable for consumer electronics. [ABSTRACT FROM AUTHOR]

In LSI testing, equivalent time sampling techniques are frequently used because the input signals to the device under test and the sampling clock are controllable; when repetitive input signals are applied to the analog device under test, its output signals can be also repetitive. In this paper, we investigate an efficient waveform acquisition method with equivalent-sampling using the metallic ratio of the sampling frequency and the input frequency, which is expected to be used for on-line, short-time and simple analog/RF/mixed-signal IC testing. We reveal that metallic sampling technique can be a powerful tool for the TDC linearity calibration with the histogram method. [ABSTRACT FROM AUTHOR]

We present a small, portable, plug–and–play time measurement instrument entirely based on Field Programmable Gate Array (FPGA). Its performance is state–of–the–art in terms of the most recent Application–Specific Integrated Circuit (ASIC) solutions of Time–to–Digital Converters (TDCs), and all operating features are fully–programmable. The instrument offers an excellent cost–performance and is suitable for detector test and time correlation measurement applications. More generally, the instrument is very well suited for fast–prototyping of systems where time measures are involved, at low cost and design effort. All the features of the instrument can be easily accessed through either the Graphical User Interface (GUI) or directly from the software Application Programming Interface (API).

A predominance of alewives (Alosa pseudoharengus), a species having high thiaminase activity, in Lake Ontario lake trout (Salvelinus namaycush) diets, has been related to thiamine deficiency in lake trout eggs during 1994–2004. The late 1990s invasion by round goby (Neogobius melanostomus), that appear to have thiaminase activity of low biological activity, represented a potential to reduce the dietary importance of alewife and, as a result, increase lake trout thiamine levels if they became sufficiently important in lake trout diets. To evaluate whether lake trout thiamine levels increased as alewives were displaced by round gobies in lake trout diets, we collected 199 lake trout ranging from 305 to 893 mm in 2005–2006 and measured their muscle thiamine levels and diet composition. Diet composition (percent by weight) was estimated from MixSIR based on stable isotopes (δ15N and δ13C) measured from lake trout and their prey. Overall, alewife and goby dominated lake trout diet (78%), with round goby dominating the diet (55–57%) of smaller individuals (<600 mm), and alewife dominating the diet (59–73%) of larger, reproductively active individuals. Lake trout muscle thiamine declined with increases in lake trout length and the proportion of alewife eaten (p < 0.01). The proportion of lake trout below 500 pmol/g thiamine also declined; this threshold is associated with a loss of equilibrium in adults. Despite the increasing albeit size-related consumption of round goby, it remains inadequate as muscle thiamine levels in mature lake trout (i.e., >600 mm) during 2005–2006 appear unchanged from levels observed in 1996. [ABSTRACT FROM AUTHOR]

Indolamines are tryptophan-derived specialized metabolites belonging to the huge and ubiquitous indole alkaloids group. Serotonin and melatonin are the best-characterized members of this family, given their many hormonal and physiological roles in animals. Following their discovery in plants, the study of plant indolamines has flourished and their involvement in important processes, including stress responses, growth and development, and reproduction, has been proposed, leading to their classification as a new category of phytohormones. However, the complex indolamine puzzle is far from resolved, particularly the biological roles of tryptamine, the early serotonin precursor representing the central hub of many downstream indole alkaloids. Tryptophan decarboxylase, which catalyzes the synthesis of tryptamine, strictly regulates the flux of carbon and nitrogen from the tryptophan pool into the indolamine pathway. Furthermore, tryptamine accumulates to high levels in the reproductive organs of many plant species and therefore cannot be classed as a mere intermediate but rather as an end product with potentially important functions in fruits and seeds. This review summarizes current knowledge on the role of tryptamine and its close relative serotonin, emphasizing the need for a clear understanding of the functions of, and mutual relations between, these indolamines and their biosynthesis pathways in plants. [ABSTRACT FROM AUTHOR]

Side-channel analysis methods can reveal the secret information of digital electronic systems by analyzing the dependency between the power consumption of implemented cryptographic algorithms and the secret data. Recent studies show that it is possible to gather information about power consumption from FPGAs without any physical access. High flexibilities of modern FPGAs cause that they are used for cloud accelerator in Platform as a Service (PaaS) system; however, new serious vulnerabilities emerged for these platforms. Although there are some reports about how switching activities from one region of FPGA affect other regions, details of this technique are not analyzed. In this paper, we analyzed the strength of this kind of attack and examined the impact of geometrical and electrical parameters of the victim/attacker modules on the efficiency of this attack. We utilized a Zynq-based Xilinx platform as the device under attack. Experimental results and analyses show that the distance between the victim module and the sensor modules is not the only effective parameter on the quality of attack; the influence of the relational location of victim/attacker modules could be more considerable on the quality of attack. Results of this analysis can help the FPGA manufacturer and IP developers to protect their systems against this serious attack. [ABSTRACT FROM AUTHOR]

This paper presents a time-to-digital converter for measuring absolute time differences. The time-to-digital converter was designed and fabricated in 0.18-um CMOS technology and it can be applied to Light Detection and Ranging system which requires long time-cover range and 50ps time resolution. Since designed time-to-digital converter adopted the reference clock of 625MHz generated by phase locked loop, it could have absolute time resolution of 50ps after automatic calibration and its cover range was over than 800ns. The time-to-digital converter adopted a counter and chain delay lines for time measurement. The counter is used for coarse time measurement and chain delay lines are used for fine time measurement. From many times experiments, fabricated time-to-digital converter has 50 ps time resolution with maximum INL of 0.8 LSB and its power consumption is about 70 mW. [ABSTRACT FROM AUTHOR]

The device miniaturization technology made possible to integrate large density of transistors in a chip to produce high computation facility. At the same time, it demands an efficient thermal management technique to handle enormous power dissipation during high performance of the chip. An active thermal management technique proposed here includes run time fully digital onchip temperature sensors, Dynamic Frequency Scaling (DFS) and active cooling topologies to enhance cooling effect of VLSI. The high resolution on chip temperature detector exhibit the temperature resolution of 0.0312°C, time resolution of 106 ps and measurement range from 0°C to 85°C with 21 sensing elements. The proposed thermal management techniques reduce the power dissipation by 30%. To enhance the thermal management capability further, there are numerous cooling methodologies developed and verified at 40 W of die power. With these topologies, the temperature of die at the power of 0 to 40 W lies between 0.5°C and 69°C. This is the worst case range amongst three cooling methodologies. The proposed work also nurtures the features of XILINX plan ahead tool's constrained effective area utilization, time constraints like TIMESPEC, TMRGRP, TPSync, TNM, Operating condition, hierarchybased synthesis and implementation for thermal management. The performance of Microblaze processors is boosted with effective area utilization, DFS and Thermo Electric Coolers (TEC). [ABSTRACT FROM AUTHOR]

Time-to-Digital Converters (TDC) are popular circuits in many applications, where high resolution time measurements are required, for example, in Positron Emission Tomography (PET). Besides its resolution, the TDC's linearity is also an important performance indicator, therefore calibration circuits usually play an important role on TDCs architectures. This paper presents an all-digital TDC implemented using Structured Datapath to reduce the need for calibration circuitry and cells custom design, without compromising the TDC's linearity. The proposed design is fully implementable using a Hardware Description Language (HDL) and enables a complete design flow automation, reducing both development time and system's complexity. The TDC is based on a Delay Locked Loop (DLL) paired with a coarse counter to increase measurement range. The proposed architecture and the design approach have proven to be efficient in developing a high resolution TDC with high linearity. The proposed TDC was implemented in TSMC 0.18 CMOS technology process achieving a resolution of 180ps, with Differential Non-Linearity (DNL) and Integral Non-Linearity (INL) under 0.6 LSB.

Accurate and rapid measuring methods for displacement of nano-scale is necessary for manipulation. Self-sensing and time-digit-conversion(TDC) are two applicable measuring methods especially suitable for room-limited workspaces and vacuum-compliance required applications, thanks to their space-saving advantage and slight thermal impact on system. The self-sensing method gives measurements in high resolution at high sampling rate but its accuracy suffers from nonlinearity, while TDC has better linearity which causes less deviation to results but has a much lower sampling rate. A Kalman filter based fusion approach with dual estimation modes and self-adaptive parameters is designed to fuse the two measurements with different sampling rates at a higher frequency. Modifications to error covariance parameters are applied to traditional Kalman filter so that sensors' generalized errors rather than their Gaussian noises are taken into consideration, and corresponding derivation is given. A series of experiments are conducted to evaluate the performance of the fused measurement.

This paper made a corresponding improvement on influence of temperature on the performance of the time-domain temperature sensor circuits. According to the qualitative relationship between temperature coefficient and size of transistors, the aspect ratio of the transistors in sensing part is improved to increase its temperature coefficient. Besides, a current mirror for temperature compensation is added to the ring oscillator of TDC(Time-to-Digital Converter) and the parameters of inverters are adjusted so that the temperature drift of TDC is near zero at the chosen temperature range. The method reduces the total power consumption and power density of the circuit, thereby reducing the performance loss caused by self-heating and self-heating of the circuit.

This article presents a 40-channel high-resolution automotive LiDAR system-on-chip (SoC), which utilizes the world’s first dual-data converter (DDC). The proposed DDC consolidates the functions of ADC and TDC into a single circuitry and achieves acquisition of both high-precision time and voltage data from the input, realizing a 5 $\times $ smaller analog front-end (AFE) area than prior arts. Such innovations lead us to a 40-channel AFE integration of the SoC without silicon cost increase, which characterizes our LiDAR system with 2 $\times $ higher pixel resolution. To enhance the ADC’s signal-to-noise and distortion ratio (SNDR) without sacrificing the area efficiency, a calibration-free and variation-tolerant voltage-controlled oscillator (VCO)-based ADC with a multiphase pulse density modulator (MP-PDM)-based feedback is proposed. Our proof-of-concept LiDAR system achieves a measurement range of 225 m at 70-klx direct sunlight, with a resolution of 240 $\times $ 192 pixels at 10 frames per second (FPS). To quantitatively measure the effect of the resolution improvement of our LiDAR, we evaluate the LiDAR’s detection accuracy of small targets 75 m away. Due to the 2 $\times $ higher vertical pixel resolution, our LiDAR can detect targets with 2 $\times $ smaller height. The 3-D point cloud of the LiDAR captured outdoor in the wild is presented. [ABSTRACT FROM AUTHOR]

This paper presents a 12-bit branching Time-to-Digital converter (TDC) fabricated in a 40 nm CMOS technology. It composes of a 6-bit coarse counter TDC, and a 6-bit fine TDC. The fine TDC utilizes a proposed branching technique to interpolate between the phases of a 16-stage gated ring oscillator, increasing its number of phases from 16 to 64. Therefore, the TDC resolution is improved to be 4 times finer. The TDC incorporates fully digital based resolution tuning capability that enables its resolution to be more stable over PVT variations. Measurement results show that the resolution tuning reduces the resolution variation by 92.3% over a temperature range of − 40 to 125 °C. However, the simple resolution tuning method causes the TDC to have a relatively large resolution of 36.2 ps. The trade-offs between TDC resolution, yield, and scalability are discussed. The proposed TDC uses simple gated inverters based samplers instead of conventional arbiters to reduce power and area consumption. In addition, power gating features of the proposed TDC enable a low power consumption of 275 µW at a sampling rate of 5 MS/s. Without any linearity calibrations, the TDC DNL, INL, single-shot precision, and figure-of-merit are measured to be 1.30 LSB, 3.61 LSB, 0.75 LSB, and 61.9 fJ/conv.-step, respectively. [ABSTRACT FROM AUTHOR]

This study investigated impacts of local skin heating on skin properties and tested whether skin changes depended on heat‐induced hyperaemia. It was reasoned that heat‐induced vasodilation impacts accompanying interstitial fluid changes. Forearm skin was locally heated from a baseline of 35°C to 40–42°C in 30 young adults (15 females, 15 males, 24.9 ± 2.1 years) and non‐heated in 10 others (5 females, 5 males, 25.2 ± 1.3 years. Skin blood flow (SBF) was continuously measured using a laser Doppler method and skin tissue dielectric constant (TDC), stratum corneum capacitance (SCC) and transepidermal water loss (TEWL) were measured before and after maintained heat for 12 min. TDC values were determined to effective measurement depths of 1.5 mm (TDC15) and 2.5 mm (TDC25). Results showed a large heat‐induced hyperaemia, with SBF increasing on average 8.8‐fold from its baseline of 35°C. Heating also caused significant increases in TDC, SCC and TEWL that, compared to preheating, increased approximately 1.1‐fold, 3.1‐fold and 4.5‐fold. None of these skin changes correlated with the magnitude of the SBF hyperaemic response. Absence of this correlation may indicate that in young healthy adults, increased capillary filtration due to heat‐induced arteriolar vasodilation is rapidly accommodated by postcapillary reabsorption, enhanced lymphatic activity and TEWL processes. An alternate explanation is that heating caused increased red cell oscillations that were detected as part of the laser Doppler increase without representing increased capillary flux. The major determinant of the Increases in TDC, SCC and TEWL is likely a consequence of heat‐induced eccrine gland activation. Studies of older persons or those with depressed function are warranted. [ABSTRACT FROM AUTHOR]