Exploring the Possibility of Photoplethysmography-Based Human Activity Recognition Using Convolutional Neural Networks.

Various sensing modalities, including external and internal sensors, have been employed in research on human activity recognition (HAR). Among these, internal sensors, particularly wearable technologies, hold significant promise due to their lightweight nature and simplicity. Recently, HAR techniques leveraging wearable biometric signals, such as electrocardiography (ECG) and photoplethysmography (PPG), have been proposed using publicly available datasets. However, to facilitate broader practical applications, a more extensive analysis based on larger databases with cross-subject validation is required. In pursuit of this objective, we initially gathered PPG signals from 40 participants engaged in five common daily activities. Subsequently, we evaluated the feasibility of classifying these activities using deep learning architecture. The model's performance was assessed in terms of accuracy, precision, recall, and F-1 measure via cross-subject cross-validation (CV). The proposed method successfully distinguished the five activities considered, with an average test accuracy of 95.14%. Furthermore, we recommend an optimal window size based on a comprehensive evaluation of performance relative to the input signal length. These findings confirm the potential for practical HAR applications based on PPG and indicate its prospective extension to various domains, such as healthcare or fitness applications, by concurrently analyzing behavioral and health data through a single biometric signal.

Formation Pattern Analysis of Spheroids Formed by a Droplet-Based Microfluidic System for Predicting the Aggressiveness of Tumor Cells.

Examining tumor heterogeneity is essential for selecting an appropriate anticancer treatment for an individual. This study aimed to distinguish low- and high-aggressive tumor cells by analyzing the formation patterns of spheroids. The droplet-based microfluidic system was employed for the formation of each spheroid from four different subtypes of breast tumor cells. Additionally, heterotypic spheroids with T lymphocytes and cancer-associated fibroblasts (CAFs) were produced, and distinctions between low- and high-aggressive tumor cells were explored through the analysis of formation patterns using circularity, convexity, and cell distributions. In both homotypic spheroids and heterotypic spheroids with T lymphocytes, spheroids formed from low-aggressive tumor cells exhibited high circularity and convexity. On the other hand, spheroids formed from high-aggressive tumor cells had relatively low circularity and convexity. In the case of heterotypic spheroids with CAFs, circularity and convexity did not exhibit clear differences between low- and high-aggressive tumor cells, but distinct variations were observed in cell distributions. CAFs and low-aggressive tumor cells were evenly distributed, whereas the CAFs were predominantly located in the inner layer, and high-aggressive tumor cells were primarily located in the outer layer. This finding can offer valuable insights into predicting the aggressiveness of unknown tumor cells.

Pain Classification using Evoked EEG Induced by Thermal Grill Illusion - Deep Neural Network Approach.

As the quantification of pain has emerged in biomedical engineering today, studies have been developing biomarkers associated with pain actively by measuring bio-signals such as electroencephalogram (EEG). Recently, some EEG studies of cold and hot pain have been reported. However, they used one type of stimulus condition for each trial and a relatively long stimulation time to collect EEG features. In this study, EEG signals during Cool (20 °C), Warm (40 °C), and Thermal Grill Illusion (TGI, 20-40 °C) stimuli were collected from 43 subjects, and were classified by a deep convolutional neural network referred to as EEGNet. Three binary classifications for the three conditions (TGI, Cool, Warm) were conducted for each subject individually. Classification accuracies for TGI-Cool, TGI-Warm, and Warm-Cool were 0.74±0.01, 0.71±0.01, and 0.74±0.01, respectively. For subjects who rated the TGI significantly hotter than the Warm stimulus, the classification accuracy for TGI-Cool (0.74±0.01) was significantly higher than for TGI-Warm (0.71±0.01). In contrast, the classification accuracy for TGI-Cool (0.72±0.03) did not differ statistically from TGI-Warm (0.73±0.01) in subjects without illusion. We found that the TGI and Cool stimuli were classified better than the TGI and Warm stimuli, implying that objective EEG features are consistent with subjective behavioral results. Further, we observed that most discriminative features between the TGI and the Cool or Warm conditions appeared in the parietal area for subjects who perceived the illusion. We postulate that the somato-sensory cortex may be activated when TGI is perceived to be hot pain.

Highly Efficient Solar Steam Generation by Glassy Carbon Foam Coated with Two-Dimensional Metal Chalcogenides.

Steam generation by eco-friendly solar energy has immense potential in terms of low-cost power generation, desalination, sanitization, and wastewater treatment. Herein, highly efficient steam generation in a bilayer solar steam generator (BSSG) is demonstrated, which is comprised of a large-area SnSe-SnSe2 layer deposited on a glassy carbon foam (CF). Both CF and SnSe-SnSe2 possess high photothermal conversion capabilities and low thermal conductivities. The combined bilayer system cumulatively converts input solar light into heat through phonon-assisted transitions in the indirect band gap SnSe-SnSe2 layer, together with trapping of sunlight via multiple scattering due to the porous morphology of the CF. This synergistic effect leads to efficient broadband solar absorption. Moreover, the low out-of-plane thermal conductivities of SnSe-SnSe2 and CF confine the generated heat at the evaporation surface, resulting in a significant reduction of heat losses. Additionally, the hydrophilic nature of the acid-treated CF offers effective water transport via capillary action, required for efficient solar steam generation in a floating form. A high evaporation rate (1.28 kg m-2 h-1) and efficiency (84.1%) are acquired under 1 sun irradiation. The BSSG system shows high recyclability, stability, and durability under repeated steam-generation cycles, which renders its practical device applications possible.

Simultaneous EEG Acquisition System for Multiple Users: Development and Related Issues.

Social interaction is one of humans' most important activities and many efforts have been made to understand the phenomenon. Recently, some investigators have attempted to apply advanced brain signal acquisition systems that allow dynamic brain activities to be measured simultaneously during social interactions. Most studies to date have investigated dyadic interactions, although multilateral interactions are more common in reality. However, it is believed that most studies have focused on such interactions because of methodological limitations, in that it is very difficult to design a well-controlled experiment for multiple users at a reasonable cost. Accordingly, there are few simultaneous acquisition systems for multiple users. In this study, we propose a design framework for an acquisition system that measures EEG data simultaneously in an environment with 10 or more people. Our proposed framework allowed us to acquire EEG data at up to 1 kHz frequency from up to 20 people simultaneously. Details of our acquisition system are described from hardware and software perspectives. In addition, various related issues that arose in the system's development-such as synchronization techniques, system loads, electrodes, and applications-are discussed. In addition, simultaneous visual ERP experiments were conducted with a group of nine people to validate the EEG acquisition framework proposed. We found that our framework worked reasonably well with respect to less than 4 ms delay and average loss rates of 1%. It is expected that this system can be used in various hyperscanning studies, such as those on crowd psychology, large-scale human interactions, and collaborative brain-computer interface, among others.

Thiazolylmethyl ortho-substituted phenyl glucoside library as novel C-aryl glucoside SGLT2 inhibitors.

In order to investigate SAR regarding proximal phenyl ring in novel C-aryl glucoside SGLT2 inhibitors containing a thiazole motif, a series of chemical modifications on proximal phenyl ring was conducted. During a series of lead optimization efforts, ortho-allyloxyphenyl 10p or ortho-hydroxyphenyl 11a showed subnanomolar inhibitory activity against hSGLT2.

Exploration of SAR regarding glucose moiety in novel C-aryl glucoside inhibitors of SGLT2.

In order to investigate SAR regarding glucose moiety in novel C-aryl glucoside SGLT2 inhibitors containing a thiazole motif, a series of chemical modifications on glucose was conducted to explore potential utility as a suitable replacement of glucose per se. Among the compounds prepared, deshydroxy 29 (IC(50)=7.01nM) demonstrated the best in vitro inhibitory activity against SGLT2 in this series to date. But, none of the compounds were better than the parent molecule 5 (IC(50)=1.75nM).

Synthesis and SAR of Thiazolylmethylphenyl Glucoside as Novel C-Aryl Glucoside SGLT2 Inhibitors.

Novel C-aryl glucoside SGLT2 inhibitors containing the thiazole motif were designed and synthesized for biological evaluation. Among the compounds assayed, thiazole containing furanyl moiety 14v and thiophenyl moiety 14y demonstrated the best in vitro inhibitory activity against SGLT2 in this series to date (IC50 = 0.720 nM for 14v and IC50 = 0.772 nM for 14y). Both of these compounds have been further evaluated on a urinary glucose excretion test and the urine volumes excreted.

Pyrimidinylmethylphenyl glucoside as novel C-aryl glucoside SGLT2 inhibitors.

Novel C-aryl glucoside SGLT2 inhibitors containing pyrimidine motif were designed and synthesized for biological evaluation. Among the compounds assayed, pyrimidine containing methylthio moiety 11 g demonstrated the best in vitro inhibitory activity against SGLT2 in this series to date (IC(50)=10.7 nM).

Discovery of 2-(4-((1H-1,2,4-triazol-1-yl)methyl)-5-(4-bromophenyl)-1-(2-chlorophenyl)-1H-pyrazol-3-yl)-5-tert-butyl-1,3,4-thiadiazole (GCC2680) as a potent, selective and orally efficacious cannabinoid-1 receptor antagonist.

Structure-activity relationship studies in a series of diarylpyrazolyl thiadiazoles identified cannabinoid-1 receptor antagonists with excellent potency and selectivity. Based on its exceptional in vivo efficacy in animal models and its favorable pharmacokinetic and toxicological profiles, 2-(4-((1H-1,2,4-triazol-1-yl)methyl)-5-(4-bromophenyl)-1-(2-chlorophenyl)-1H-pyrazol-3-yl)-5-tert-butyl-1,3,4-thiadiazole (GCC2680) was selected as a preclinical candidate for the treatment of obesity.

Synthesis of pyridazine and thiazole analogs as SGLT2 inhibitors.

With anticipation of the improvement in biological aspects in our SGLT2 program, novel pyridazinyl and thiazolyl analogs were designed and efficiently synthesized. The installation of the pyridazine ring at the anomeric carbon of d-glucopyranose was carried out in a stereoselective fashion. On the other hand, a series of thiazolyl analogs was also synthesized through a coupling reaction between perbenzyl gluconolactone 9 and 2-lithiothiazole. Biological activities of the compounds thus prepared were evaluated by the in vitro SGLT2 inhibition assay. Considering assay results, the novel benzylpyridazinyl and benzylthiazolyl analogs, disclosed in this article, could be a quick reference to prospective SGLT2 inhibitors useful for pharmacotherapy.

Novel C-aryl glucoside SGLT2 inhibitors as potential antidiabetic agents: Pyridazinylmethylphenyl glucoside congeners.

Novel C-aryl glucoside SGLT2 inhibitors containing pyridazine motif were designed and synthesized for biological evaluation. Among the compounds tested, pyridazine containing methylthio moiety 22l or thiadiazole ring 22ah showed the best in vitro inhibitory activities in this series (IC(50)=13.4, 11.4nM, respectively) against SGLT2 to date. Subsequently, compound 22l exhibited reasonable urinary glucose excretion and glucosuria in normal SD rats, thereby demonstrating that this pyridazine series possesses both in vitro SGLT2 inhibition and in vivo efficacy, albeit to a lower degree.

Novel C-aryl glucoside SGLT2 inhibitors as potential antidiabetic agents: 1,3,4-Thiadiazolylmethylphenyl glucoside congeners.

Novel C-aryl glucoside SGLT2 inhibitors containing 1,3,4-thiadiazole moieties were designed and synthesized. Among the compounds tested, biaryl-type compounds containing pyrazine 59, 2-furan 61, and 3-thiophene 71 showed the best in vitro inhibitory activities to date (IC(50) = 3.51-7.03 nM) against SGLT2. A selected compound 61, demonstrated reasonable blood glucose-lowering effects, indicating that the information obtained from the SAR studies in this 1,3,4-thiadiazolylmethylphenyl glucoside series might help to design more active SGLT2 inhibitors that are structurally related.

Synthesis and structure-activity relationship of 1,2,4-triazole-containing diarylpyrazolyl carboxamide as CB1 cannabinoid receptor-ligand.

Numerous research groups have been engaged in searching for novel CB1 receptor antagonists, since SR141716A (rimonabant), a CB1 receptor antagonist, proved to be efficacious in human for the treatment of obesity. In the present study, a series of 1,2,4-triazole-containing diarylpyrazolyl carboxamides based on the 1,5-diarylpyrazole template of rimonabant, was synthesized and tested for CB1 receptor binding affinity. The structure-activity relationship studies demonstrated that incorporation of 1,2,4-triazole ring onto the pyrazole scaffold via a methylene linker led to a significant improvement for CB1 receptor binding affinity. Importantly, these analogues also exhibited excellent selectivity for CB1 receptor over CB2 receptor.

Pentacycle derivatives as cannabinoid CB1 receptor ligands.

Cannabinoid CB-1 receptors have been the focus of extensive studies since the first clinical results of rimonabant (SR141716) for the treatment of obesity and obesity-related metabolic disorders were reported in 2001. To further evaluate the properties of CB receptors, we have designed and efficiently prepared a series of pentacycle derivatives. Five of the new compounds which displayed high in vitro rCB1 binding affinities were assayed for binding to hCB2 receptor. Noticeably, 2-(5-(4-bromophenyl)-1-(2,4-dichlorophenyl)-4-(5-methyl-1,3,4-thiadiazol-2-yl)-1H-pyrazol-3-yl)-5-(1-(trifluoromethyl)cyclopropyl)-1,3,4-oxadiazole (16l) demonstrated good binding affinity and decent selectivity for rCB1 receptor (IC(50)=1.72 nM, hCB2/rCB1=142).

Substituted pyrimidines as cannabinoid CB1 receptor ligands.

Cannabinoid CB1 receptors have been the avenue of extensive studies since the first clinical results of rimonabant (SR141716) for the treatment of obesity and obesity-related metabolic disorders were reported in 2001. To further evaluate the properties of CB receptors, we have designed and efficiently prepared a series of substituted pyrimidines based on chemical structure of Merck's taranabant, a cannabinoid CB1 receptor inverse agonist. Noticeably, N4-((2S,3S)-3-(3-bromophenyl)-4-(4-chlorophenyl)butan-2-yl)-N6-butylpyrimidine-4,6-diamine (13b) demonstrated good binding affinity and decent selectivity for CB1 receptor (IC(50)=16.3nM, CB2/CB1=181.6).

Synthesis and structure-activity relationship of novel diarylpyrazole imide analogues as CB1 cannabinoid receptor ligands.

A myriad of research groups have been engaged in searching for novel CB1 receptor antagonists, since SR141716A (rimonabant), a CB1 receptor antagonist, was discovered for an obesity treatment. In this research, extended series, based on the 1,5-diarylpyrazole template of rimonabant, was synthesized and tested for CB1 receptor binding affinity. In the present study, N-piperidinylcarboxamide group of rimonabant was replaced with the corresponding sulfonamide, imide, N-methyl imide and methylenediamide, respectively. The SAR studies to optimize the CB1 binding affinity led to the potent imide derivatives. The in vivo efficacy test of a derivative (16f) gave a promising result for this novel scaffold. In order to explore physicochemical properties (hydrophobic, steric and electronic) of the representative imide derivatives responsible for their CB1 receptor binding affinity, quantitative structure activity relationship (QSAR) studies were performed. Hansch QSAR models, which were moderate in the explanation for SAR, were generated with hydrophobic, steric and electronic properties of substituents. Especially, the Taft Es-based parabolic model was obtained with the best correlation result (r(2)=0.846).

Oxadiazole-diarylpyrazole 4-carboxamides as cannabinoid CB1 receptor ligands.

Cannabinoid CB-1 receptors have been the focus of extensive studies since the first clinical results of rimonabant (SR141716) for the treatment of obesity and obesity-related metabolic disorders were reported in 2001. To further evaluate the properties of CB receptors, we have designed and efficiently prepared a series of oxadiazole-diarylpyrazole 4-carboxamides. Six of the new compounds which displayed high in vitro CB1 binding affinities were assayed for binding to CB2 receptor. Noticeably, 5-(4-bromophenyl)-3-(5-tert-butyl-1,3,4-oxadiazol-2-yl)-1-(2,4-dichlorophenyl)-N-phenyl-1H-pyrazole-4-carboxamide (12q) and 5-(4-bromophenyl)-3-(5-tert-butyl-1,3,4-oxadiazol-2-yl)-1-(2,4-dichlorophenyl)-N-(pyridin-2-yl)-1H-pyrazole-4-carboxamide (12r) demonstrated good binding affinity and decent selectivity for CB1 receptor (IC(50) = 1.35 nM, CB2/CB1 = 286 for 12q; IC(50) = 1.46 nM, CB2/CB1 = 256 for 12r).

Do children perceive postural constraints when estimating reach or action planning?

Estimation of whether an object is reachable from a specific body position constitutes an important aspect in effective motor planning. Researchers who estimate reachability by way of motor imagery with adults consistently report the tendency to overestimate, with some evidence of a postural effect (postural stability hypothesis). This idea suggests that perceived reaching limits depend on an individual's perceived postural constraints. Based on previous work with adults, the authors expected a significant postural effect with the Reach 2 condition, as evidenced by reduced overestimation. Furthermore, the authors hypothesized that the postural effect would be greater in younger children. They then tested these propositions among children aged 7, 9, and 11 years by asking them to estimate reach while seated (Reach 1) and in the more demanding posture of standing on 1 foot and leaning forward (Reach 2). Results indicated no age or condition difference, therefore providing no support for a postural effect. When the authors compared these data to a published report of adults, a developmental difference emerged. That is, adults recognize the perceived postural constraint of the standing position resulting in under- rather than overestimation, as displayed in the seated condition. Although preliminary, these observations suggest that estimates of reach (action planning) continue to be refined between late childhood and young adulthood.

A question of intention in motor imagery.

We examined the question-is the intention of completing a simulated motor action the same as the intention used in processing overt actions? Participants used motor imagery to estimate distance reachability in two conditions: Imagery-Only (IO) and Imagery-Execution (IE). With IO (red target) only a verbal estimate using imagery was given. With IE (green target) participants knew that they would actually reach after giving a verbal estimate and be judged on accuracy. After measuring actual maximum reach, used for the comparison, imagery targets were randomly presented across peripersonal- (within reach) and extrapersonal (beyond reach) space. Results indicated no difference in overall accuracy by condition, however, there was a significant distinction by space; participants were more accurate in peripersonal space. Although more research is needed, these findings support an increasing body of evidence suggesting that the neurocognitive processes (in this case, intention) driving motor imagery and overt actions are similar.