Effectiveness of breath acetone monitoring in reducing body fat and improving body composition: a randomized controlled study.

When attempts to lose body fat mass frequently fail, breath acetone (BA) monitoring may assist fat mass loss during a low-carbohydrate diet as it can provide real-time body fat oxidation levels. This randomized controlled study aimed to evaluate the effectiveness of monitoring BA levels and providing feedback on fat oxidation during a three-week low-carbohydrate diet intervention. Forty-seven participants (mean age = 27.8 ± 4.4 years, 53.3% females, body mass index = 24.1 ± 3.4 kg m-2) were randomly assigned to three groups (1:1:1 ratio): daily BA assessment with a low-carbohydrate diet, body weight assessment (body scale (BS)) with a low-carbohydrate diet, and low-carbohydrate diet only. Primary outcome was the change in fat mass and secondary outcomes were the changes in body weight and body composition. Forty-five participants completed the study (compliance rate: 95.7%). Fat mass was significantly reduced in all three groups (allP< 0.05); however, the greatest reduction in fat mass was observed in the BA group compared to the BS (differences in changes in fat mass, -1.1 kg; 95% confidence interval: -2.3, -0.2;P= 0.040) and control (differences in changes in fat mass, -1.3 kg; 95% confidence interval: -2.1, -0.4;P= 0.013) groups. The BA group showed significantly greater reductions in body weight and visceral fat mass than the BS and control groups (allP< 0.05). In addition, the percent body fat and skeletal muscle mass were significantly reduced in both BA and BS groups (allP< 0.05). However, no significant differences were found in changes in body fat percentage and skeletal muscle mass between the study groups. Monitoring BA levels, which could have motivated participants to adhere more closely to the low-carbohydrate diet, to assess body fat oxidation rates may be an effective intervention for reducing body fat mass (compared to body weight assessment or control conditions). This approach could be beneficial for individuals seeking to manage body fat and prevent obesity.

Revealing the Substrate Constraint Effect on the Thermodynamic Behaviour of the Pd-H through Capacitive-Based Hydrogen-Sorption Measurement.

Mechanical constraints imposed on the Pd-H system can induce significant strain upon hydrogenation-induced expansion, potentially leading to changes in the thermodynamic behavior, such as the phase-transition pressure. However, the investigation of the constraint effect is often tricky due to the lack of simple experimental techniques for measuring hydrogenation-induced expansion. In this study, a capacitive-based measurement system is developed to monitor hydrogenation-induced areal expansion, which allows us to control and evaluate the magnitude of the substrate constraint. By using the measurement technique, the influence of substrate constraint intensity on the thermodynamic behavior of the Pd-H system is investigated. Through experiments with different constraint intensities, it is found that the diffefrence in the constraint intensity minimally affects the phase-transition pressure when the Pd-H system allows the release of constraint stress through plastic deformation. These experiments can improve the understanding of the substrate constraint behaviours of Pd-H systems allowing plastic deformation while demonstrating the potential of capacitive-based measurement systems to study the mechanical-thermodynamic coupling of M-H systems.

N-Carbon-Doped Binary Nanophase of Metal Oxide/Metal-Organic Framework for Extremely Sensitive and Selective Gas Response.

Metal-organic frameworks (MOFs), which are highly ordered structures exhibiting sub-nanometer porosity, possess significant potential for diverse gas applications. However, their inherent insulative properties limit their utility in electrochemical gas sensing. This investigation successfully modifies the electrical conductivity of zeolitic imidazolte framework-8 (ZIF-8) employing a straightforward surface oxidation methodology. A ZIF-8 polycrystalline layer is applied on a wafer-scale oxide substrate and subjects to thermal annealing at 300 °C under ambient air conditions, resulting in nanoscale oxide layers while preserving the fundamental properties of the ZIF-8. Subsequent exposure to NO2 instigates the evolution of an electrically interconnected structure with the formation of electron-rich dopants derived from the decomposition of nitrogen-rich organic linkers. The N-carbon-hybridized ZnO/ZIF-8 device demonstrates remarkable sensitivity (≈130 ppm-1 ) and extreme selectivity in NO2 gas detection with a lower detection limit of 0.63 ppb under 150 °C operating temperature, surpassing the performance of existing sensing materials. The exceptional performances result from the Debye length scale dimensionality of ZnO and the high affinity of ZIF-8 to NO2 . The methodology for manipulating MOF conductivity through surface oxidation holds the potential to accelerate the development of MOF-hybridized conductive channels for a variety of electrical applications.

The effect of a short-term ketogenic diet on exercise efficiency during graded exercise in healthy adults.

OBJECTIVE: We examined the effects of short-term KD on exercise efficiency and hormonal response during and after the graded exercise testing. METHODS: Fourteen untrained healthy adults (8 males, 6 females, age 26.4 ± 3.1 [SD] years; BMI 24.8 ± 4.6 kg/m2; peak VO2max 54.0 ± 5.8 ml/kg FFM/min) completed 3-days of a mixed diet (MD) followed by another 3-days of KD after 3-days of washout period. Upon completion of each diet arm, participants underwent graded exercise testing with low- (LIE; 40% of VO2max), moderate- (MIE; 55%), and high-intensity exercise (HIE; 70%). Exercise efficiency was calculated as work done (kcal/min)/energy expenditure (kcal/min). RESULTS: Fat oxidation during the recovery period was higher in KD vs. MD. Despite identical workload during HIE, participants after having KD vs. MD showed higher energy expenditure and lower exercise efficiency (10.1 ± 0.7 vs. 12.5 ± 0.3%, p < .01). After KD, free fatty acid (FFA) concentrations were higher during MIE and recovery vs. resting, and beta-hydroxybutylate (BOHB) was lower at HIE vs. resting. Cortisol concentrations after KD was higher during recovery vs. resting, with no significant changes during graded exercise testing after MD. CONCLUSIONS: Our data suggest that short-term KD is favorable to fat metabolism leading increased circulating FFA and BOHB during LIE to MIE. However, it is notable that KD may cause 1) exercise inefficiency manifested by increased energy expenditure and 2) elevated exercise stress during HIE and recovery. Trial registration: KCT0005172, International Clinical Trials Registry Platform.

Multicolor Conjugated Polymer Thin Films with Tunable Responsivity to Oxidative and Reductive Environments.

Dynamic colors that respond to environmental changes are of great interest for diverse areas of science and technology ranging from chemical and biological sensors to smart information display. Here, we demonstrate a multitude of responsive colors from a conjugated polymer film arising from a thin-film interference. This mechanism provides an excellent control over the thin-film color by varying the film thickness, type of substrate, and degree of polaron population and is generally applicable to various conjugated polymers for further color variation. Furthermore, multiple sets of responsive colors are achieved from a single polymer layer by patterning the underlying substrate to spatially modify the interference conditions. Using this system, we demonstrate the reversible color changes induced by an oxidative or reductive environment with color responsivity controllable with the nature of the polaron state.

Firmly interlocked Janus-type metallic Ni3Sn2S2-carbon nanotube heterostructure suppresses polysulfide dissolution and Sn aggregation.

Ternary transition-metal tin chalcogenides, with their diverse compositions, abundant constituents, high theoretical capacities, acceptable working potentials, excellent conductivities, and synergistic active/inactive multi-components, hold promise as anode materials for metal-ion batteries. However, abnormal aggregation of Sn nanocrystals and the shuttling of intermediate polysulfides during electrochemical tests detrimentally affect the reversibility of redox reactions and lead to rapid capacity fading within a limited number of cycles. In this study, we present the development of a robust Janus-type metallic Ni3Sn2S2-carbon nanotube (NSSC) heterostructured anode for Li-ion batteries (LIBs). The synergistic effects of Ni3Sn2S2 nanoparticles and a carbon network successfully generate abundant heterointerfaces with steady chemical bridges, thereby enhancing ion and electron transport, preventing the aggregation of Ni and Sn nanoparticles, mitigating the oxidation and shuttling of polysulfides, facilitating the reforming of Ni3Sn2S2 nanocrystals during delithiation, creating a uniform solid-electrolyte interphase (SEI) layer, protecting the mechanical integrity of electrode materials, and ultimately enabling highly reversible lithium storage. Consequently, the NSSC hybrid exhibits an excellent initial Coulombic efficiency (ICE > 83 %) and superb cyclic performance (1218 mAh/g after 500 cycles at 0.2 A/g and 752 mAh/g after 1050 cycles at 1 A/g). This research provides practical solutions for the intrinsic challenges associated with multi-component alloying and conversion-type electrode materials in next-generation metal-ion batteries.

Superlubricity with Graphitization in Ti-Doped DLC/Steel Tribopair: Response on Humidity and Temperature.

The anti-friction of diamond-like carbon (DLC) is achieved by a well-developed carbonaceous transfer layer, and Ti-doped DLC is developed into a robustly built-up carbonaceous transfer layer. The friction performance of DLC depends on the operating environment, e.g., ambient gas, humidity, temperature, lubricants, and mating material. In this study, we aimed to reveal the environmental sensitivities of Ti-DLC on friction characteristics. To this end, a Ti-DLC was rubbed against a steel ball, and friction behaviors were evaluated with different gas compositions, humidity, and temperature. Finally, we identified that fractional coverage of water on surfaces affected the anti-graphitization on Ti-DLC, leading to avoiding friction reduction.

Environmentally friendly, highly efficient, and large stokes shift-emitting ZnSe:Mn2+/ZnS core/shell quantum dots for luminescent solar concentrators.

In this study, heavy-metal-free orange light-emitting ZnSe:Mn2+/ZnS doped-core/shell (d-C/S) quantum dots (QDs) were synthesized using a nucleation doping strategy. To synthesize high quality d-C/S QDs with high photoluminescence (PL) quantum yield (QY), the Mn2+ concentration was optimized. The resulting ZnSe:Mn2+(5%)/ZnS d-C/S QDs showed a high PL QY of 83.3%. The optical properties of the synthesized QDs were characterized by absorption and PL spectroscopy. Their structural and compositional properties were studied by X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. After doping Mn2+ into a ZnSe core, the ZnSe:Mn2+/ZnS d-C/S QDs showed a large Stokes shift of 170 nm. The ZnSe:Mn2+/ZnS d-C/S QDs were embedded in a poly(lauryl methacrylate) (PLMA) polymer matrix and the ZnSe:Mn2+/ZnS-based polymer film was fabricated. The fabricated ZnSe:Mn2+/ZnS-PLMA film was highly transparent in the visible spectral region (transmittance > 83.8% for λ ≥ 450 nm) and it exhibited bright orange light under air mass (AM) 1.5G illumination using a solar simulator. The optical path-dependent PL measurement of the ZnSe:Mn2+/ZnS-PLMA film showed no PL band shift and minimal PL decrease under variation of excitation position. These results indicate that the highly efficient and large Stokes shift-emitting ZnSe:Mn2+/ZnS QDs are promising for application to luminescent solar concentrators.

Enhanced Thermoelectric Power Factor in Carrier-Type-Controlled Platinum Diselenide Nanosheets by Molecular Charge-Transfer Doping.

2D transition metal dichalcogenides (TMDCs) have revealed great promise for realizing electronics at the nanoscale. Despite significant interests that have emerged for their thermoelectric applications due to their predicted high thermoelectric figure of merit, suitable doping methods to improve and optimize the thermoelectric power factor of TMDCs have not been studied extensively. In this respect, molecular charge-transfer doping is utilized effectively in TMDC-based nanoelectronic devices due to its facile and controllable nature owing to a diverse range of molecular designs available for modulating the degree of charge transfer. In this study, the power of molecular charge-transfer doping is demonstrated in controlling the carrier-type (n- and p-type) and thermoelectric power factor in platinum diselenide (PtSe2 ) nanosheets. This, combined with the tunability in the band overlap by changing the thickness of the nanosheets, allows a significant increase in the thermoelectric power factor of the n- and p-doped PtSe2 nanosheets to values as high as 160 and 250 µW mK-2 , respectively. The methodology employed in this study provides a simple and effective route for the molecular doping of TMDCs that can be used for the design and development of highly efficient thermoelectric energy conversion systems.

Highly Sensitive and Selective Detection of Hydrogen Using Pd-Coated SnO2 Nanorod Arrays for Breath-Analyzer Applications.

We report a breath hydrogen analyzer based on Pd-coated SnO2 nanorods (Pd-SnO2 NRs) sensor integrated into a miniaturized gas chromatography (GC) column. The device can measure a wide range of hydrogen (1-100 ppm), within 100 s, using a small volume of human breath (1 mL) without pre-concentration. Especially, the mini-GC integrated with Pd-SnO2 NRs can detect 1 ppm of H2, as a lower detection limit, at a low operating temperature of 152 °C. Furthermore, when the breath hydrogen analyzer was exposed to a mixture of interfering gases, such as carbon dioxide, nitrogen, methane, and acetone, it was found to be capable of selectively detecting only H2. We found that the Pd-SnO2 NRs were superior to other semiconducting metal oxides that lack selectivity in H2 detection. Our study reveals that the Pd-SnO2 NRs integrated into the mini-GC device can be utilized in breath hydrogen analyzers to rapidly and accurately detect hydrogen due to its high selectivity and sensitivity.

Modulation of Conductivity and Contact Resistance of RuO2 Nanosheets via Metal Nano-Particles Surface Decoration.

We studied the variation in electrical conductivity of exfoliated RuO2 nanosheets and the modulation in the contact resistance of individual nanosheet devices using charge transfer doping effects based on surface metal nanoparticle decorations. The electrical conductivity in the monolayer and bilayer RuO2 nanosheets gradually increased due to the surface decoration of Cu, and subsequently Ag, nanoparticles. We obtained contact resistances between the nanosheet and electrodes using the four-point and two-point probe techniques. Moreover, the contact resistances decreased during the surface decoration processes. We established that the surface decoration of metal nanoparticles is a suitable method for external contact engineering and the modulation of the internal properties of nanomaterials.

Hydrogen Gas Sensors Using Palladium Nanogaps on an Elastomeric Substrate.

With the recent reillumination of the hydrogen economy around the world, the demand for H2 sensors is expected to increase rapidly. Due to safety issues caused by the highly flammable and explosive character of hydrogen gas (H2 ), it is imperative to develop the sensors that can quickly and sensitively detect H2 leaks. For the development of H2 sensors, Pd-based materials have been extensively used due to the high affinity of Pd metal for H2 . Among Pd-based H2 sensors, Pd nanogap-based sensors have been extensively investigated because these sensors can operate in an on-off manner, which enables them to have improved sensing capabilities, including high sensitivity, rapid response, short recovery time, and good reliability. Importantly, significant advances in H2 -sensing performance have been achieved by simply using an elastomeric substrate to form Pd nanogaps. Herein, the progress and advanced approaches achieved over the last decade for Pd nanogap-based H2 sensors supported on elastomeric substrates are reviewed, with a focus on strategies to reduce detection limits and increase reliability, sensitivity, and stability.

Breath Acetone Measurement-Based Prediction of Exercise-Induced Energy and Substrate Expenditure.

The purpose of our study was to validate a newly developed breath acetone (BrAce) analyzer, and to explore if BrAce could predict aerobic exercise-related substrate use. Six healthy men ran on a treadmill at 70% of maximal oxygen consumption (VO2max) for 1 h after two days of a low-carbohydrate diet. BrAce and blood ketone (acetoacetate (ACAC), beta-hydroxybutyrate (BOHB)) levels were measured at baseline and at different time points of post-exercise. BrAce values were validated against blood ketones and respiratory exchange ratio (RER). Our results showed that BrAce was moderately correlated with BOHB (r = 0.68, p < 0.01), ACAC (r = 0.37, p < 0.01) and blood ketone (r = 0.60, p < 0.01), suggesting that BrAce reflect blood ketone levels, which increase when fat is oxidized. Furthermore, BrAce also negatively correlated with RER (r = 0.67, p < 0.01). In our multiple regression analyses, we found that when BMI and VO2max were added to the prediction model in addition to BrAce, R2 values increased up to 0.972 at rest and 0.917 at 1 h after exercise. In conclusion, BrAce level measurements of our BrAce analyzer reflect blood ketone levels and the device could potentially predict fat oxidation.

All-in-One Piezo-Triboelectric Energy Harvester Module Based on Piezoceramic Nanofibers for Wearable Devices.

An all-in-one energy harvester module comprising a top piezoelectric layer, a bottom piezoelectric layer, and a middle triboelectric layer was fabricated based on flexible piezoceramic nanofibers to serve as a power source for wearable devices. The top and bottom piezoelectric layers were manufactured by modularizing electrospun piezoceramic nanofibers with an interdigitated electrode, and the energy harvesting characteristics were maximized by laminating the single modules in z-axis array arrangements. The triboelectric layer was manufactured by attaching polydimethylsiloxane on both sides of an electrode layer, and the energy harvesting characteristics were controlled according to the surface roughness of the triboelectric modules. The output voltages of the individual energy harvester modules of the all-in-one module were individually or integrally measured by hand pressing the lower and upper parts of the module. The all-in-one energy harvester module generated a maximum voltage (power) of 253 V (3.8 mW), and the time required to charge a 0.1 µF capacitor to 25 V was 40 s. The results of a simulated energy harvesting experiment conducted on the all-in-one energy harvester module showed that 42 LED bulbs arranged in the shape of the "KICET" logo could be turned on in real time without charging, and a mini fan consuming a power of 3.5 W was operated after charging a 10 µF capacitor for 250 s. This work shows the potential of the all-in-one module as an ecofriendly flexible energy harvester for operating wearable devices.

Neutrophils Recirculate through Lymph Nodes to Survey Tissues for Pathogens.

The adaptive immune function of lymph nodes is dependent on constant recirculation of lymphocytes. In this article, we identify neutrophils present in the lymph node at steady state, exhibiting the same capacity for recirculation. In germ-free mice, neutrophils still recirculate through lymph nodes, and in mice cohoused with wild microbiome mice, the level of neutrophils in lymph nodes increases significantly. We found that at steady state, neutrophils enter the lymph node entirely via L-selectin and actively exit via efferent lymphatics via an S1P dependent mechanism. The small population of neutrophils in the lymph node can act as reconnaissance cells to recruit additional neutrophils in the event of bacterial dissemination to the lymph node. Without these reconnaissance cells, there is a delay in neutrophil recruitment to the lymph node and a reduction in swarm formation following Staphylococcus aureus infection. This ability to recruit additional neutrophils by lymph node neutrophils is initiated by LTB4. This study establishes the capacity of neutrophils to recirculate, much like lymphocytes via L-selectin and high endothelial venules in lymph nodes and demonstrates how the presence of neutrophils at steady state fortifies the lymph node in case of an infection disseminating through lymphatics.

Near-field sub-diffraction photolithography with an elastomeric photomask.

Photolithography is the prevalent microfabrication technology. It needs to meet resolution and yield demands at a cost that makes it economically viable. However, conventional far-field photolithography has reached the diffraction limit, which imposes complex optics and short-wavelength beam source to achieve high resolution at the expense of cost efficiency. Here, we present a cost-effective near-field optical printing approach that uses metal patterns embedded in a flexible elastomer photomask with mechanical robustness. This technique generates sub-diffraction patterns that are smaller than 1/10th of the wavelength of the incoming light. It can be integrated into existing hardware and standard mercury lamp, and used for a variety of surfaces, such as curved, rough and defect surfaces. This method offers a higher resolution than common light-based printing systems, while enabling parallel-writing. We anticipate that it will be widely used in academic and industrial productions.

Untethered Soft Robotics with Fully Integrated Wireless Sensing and Actuating Systems for Somatosensory and Respiratory Functions.

There has been a great deal of interest in designing soft robots that can mimic a human system with haptic and proprioceptive functions. There is now a strong demand for soft robots that can sense their surroundings and functions in harsh environments. This is because the wireless sensing and actuating capabilities of these soft robots are very important for monitoring explosive gases in disaster areas and for moving through contaminated environments. To develop these wireless systems, complex electronic circuits must be integrated with various sensors and actuators. However, the conventional electronic circuits based on silicon are rigid and fragile, which can limit their reliable integration with soft robots for achieving continuous locomotion. In our study, we developed an untethered, soft robotic hand that mimics human fingers. The soft robotic fingers are composed of a thermally responsive elastomer composite that includes capsules of ethanol and liquid metals for its shape deformation through an electrothermal phase transition. And these soft actuators are integrated fully with flexible forms of heaters, with pressure, temperature, and hydrogen gas sensors, and wireless electronic circuits. Entire functions of this soft hand, including the gripping motion of soft robotic fingers and the real-time detections of tactile pressures, temperatures, and hydrogen gas concentrations, are monitored or controlled wirelessly using a smartphone. This wireless sensing and actuating system for somatosensory and respiratory functions of a soft robot provides a promising strategy for next-generation robotics.

Strong Thermopower Enhancement and Tunable Power Factor via Semimetal to Semiconductor Transition in a Transition-Metal Dichalcogenide.

Electronic band engineering is a promising approach to enhance the thermopower of thermoelectric materials. In transition-metal dichalcogenides (TMDCs), this has so far only been achieved using their inherent semiconducting nature. Here, we report the thickness-modulated band engineering of nanosheets based on semimetallic platinum diselenide (PtSe2) resulting in a thermopower enhancement of more than 50 times than that of the bulk. We obtained this by introducing a semimetal to semiconductor (SMSC) transition resulting in the formation of a bandgap. This approach based on semimetallic TMDCs provides potential advantages such as a large variation of transport properties, a decrease of the ambipolar transport effect, and a high carrier density dependence of the transport properties. Our observations suggest that the SMSC transition in TMDCs is a promising and straightforward strategy for the development of two-dimensional nanostructured thermoelectric materials.

Selective Detection of Nitrogen-Containing Compound Gases.

N-containing gaseous compounds, such as trimethylamine (TMA), triethylamine (TEA), ammonia (NH3), nitrogen monoxide (NO), and nitrogen dioxide (NO2) exude irritating odors and are harmful to the human respiratory system at high concentrations. In this study, we investigated the sensing responses of five sensor materials-Al-doped ZnO (AZO) nanoparticles (NPs), Pt-loaded AZO NPs, a Pt-loaded WO3 (Pt-WO3) thin film, an Au-loaded WO3 (Au-WO3) thin film, and N-doped graphene-to the five aforementioned gases at a concentration of 10 parts per million (ppm). The ZnO- and WO3-based materials exhibited n-type semiconducting behavior, and their responses to tertiary amines were significantly higher than those of nitric oxides. The N-doped graphene exhibited p-type semiconducting behavior and responded only to nitric oxides. The Au- and Pt-WO3 thin films exhibited extremely high responses of approximately 100,000 for 10 ppm of triethylamine (TEA) and approximately -2700 for 10 ppm of NO2, respectively. These sensing responses are superior to those of previously reported sensors based on semiconducting metal oxides. On the basis of the sensing response results, we drew radar plots, which indicated that selective pattern recognition could be achieved by using the five sensing materials together. Thus, we demonstrated the possibility to distinguish each type of gas by applying the patterns to recognition techniques.

Fast Online Coordinate Correction of a Multi-Sensor for Object Identification in Autonomous Vehicles.

Multi-sensor perception systems may have mismatched coordinates between each sensor even if the sensor coordinates are converted to a common coordinate. This discrepancy can be due to the sensor noise, deformation of the sensor mount, and other factors. These mismatched coordinates can seriously affect the estimation of a distant object's position and this error can result in problems with object identification. To overcome these problems, numerous coordinate correction methods have been studied to minimize coordinate mismatching, such as off-line sensor error modeling and real-time error estimation methods. The first approach, off-line sensor error modeling, cannot cope with the occurrence of a mismatched coordinate in real-time. The second approach, using real-time error estimation methods, has high computational complexity due to the singular value decomposition. Therefore, we present a fast online coordinate correction method based on a reduced sensor position error model with dominant parameters and estimate the parameters by using rapid math operations. By applying the fast coordinate correction method, we can reduce the computational effort within the necessary tolerance of the estimation error. By experiments, the computational effort was improved by up to 99.7% compared to the previous study, and regarding the object's radar the identification problems were improved by 94.8%. We conclude that the proposed method provides sufficient correcting performance for autonomous driving applications when the multi-sensor coordinates are mismatched.