jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Michael Niepmann
Source: Cancers (review, 2024-06-21)
Field: Chemistry — Organic Chemistry

Importance of Michaelis Constants for Cancer Cell Redox Balance and Lactate Secretion—Revisiting the Warburg Effect Cancer cells metabolize a large fraction of glucose to lactate, even under a sufficient oxygen supply. This phenomenon-the "Warburg Effect"-is often regarded as not yet understood. Cancer cells change gene expression to increase the uptake and utilization of glucose for biosynthesis pathways and glycolysis, but they do not adequately up-regulate the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS). Thereby, an increased glycolytic flux causes an increased production of cytosolic NADH. However, since the corresponding gene expression changes are not neatly fine-tuned in the cancer cells, cytosolic NAD<sup>+</sup> must often be regenerated by loading excess electrons onto pyruvate and secreting the resulting lactate, even under sufficient oxygen supply. Interestingly, the Michaelis constants (K<sub>M</sub> values) of the enzymes at the pyruvate junction are sufficient to explain the priorities for pyruvate utilization in cancer cells: 1. mitochondrial OXPHOS for efficient ATP production, 2. electrons that exceed OXPHOS capacity need to be disposed of and secreted as lactate, and 3. biosynthesis reactions for cancer cell growth. In other words, a number of cytosolic electrons need to take the "emergency exit" from the cell by lactate secretion to maintain the cytosolic redox balance. Warburg effect ; Redox ; Michaelis–Menten kinetics ; Balance (ability) ; Chemistry ; Secretion ; Kinetics ; Cell ; Glycolysis ; Biochemistry ; Biology ; Metabolism ; Physics ; Neuroscience ; Enzyme ; Inorganic chemistry Free Radicals and Antioxidants ; Cancer, Hypoxia, and Metabolism ; ATP Synthase and ATPases Research
Authors: Zekun Li | Nadia Benabdallah | Richard Laforest | Richard L. Wahl | Daniel L.J. Thorek | Abhinav K. Jha
Source: IEEE Transactions on Medical Imaging (article, 2024-07-05)
Field: Chemistry — Inorganic Chemistry

Joint Regional Uptake Quantification of Thorium-227 and Radium-223 Using a Multiple-Energy-Window Projection-Domain Quantitative SPECT Method Thorium-227 ( )-based -particle radiopharmaceutical therapies ( -RPTs) are currently being investigated in several clinical and pre-clinical studies. After administration, decays to , another -particle-emitting isotope, which redistributes within the patient. Reliable dose quantification of both and is clinically important, and SPECT may perform this quantification as these isotopes also emit X- and -ray photons. However, reliable quantification is challenging for several reasons: the orders-of-magnitude lower activity compared to conventional SPECT, resulting in a very low number of detected counts, the presence of multiple photopeaks, substantial overlap in the emission spectra of these isotopes, and the image-degrading effects in SPECT. To address these issues, we propose a multiple-energy-window projection-domain quantification (MEW-PDQ) method that jointly estimates the regional activity uptake of both and directly using the SPECT projection data from multiple energy windows. We evaluated the method with realistic simulation studies conducted with anthropomorphic digital phantoms, including a virtual imaging trial, in the context of imaging patients with bone metastases of prostate cancer who were treated with -based -RPTs. The proposed method yielded reliable (accurate and precise) regional uptake estimates of both isotopes and outperformed state-of-the-art methods across different lesion sizes and contrasts, as well as in the virtual imaging trial. This reliable performance was also observed with moderate levels of intra-regional heterogeneous uptake as well as when there were moderate inaccuracies in the definitions of the support of various regions. Additionally, we demonstrated the effectiveness of using multiple energy windows and the variance of the estimated uptake using the proposed method approached the Cramér-Rao-lower-bound-defined theoretical limit. These results provide strong evidence in support of this method for reliable uptake quantification in -based -RPTs. Thorium ; Radium ; Joint (building) ; Projection (relational algebra) ; Window (computing) ; Energy (signal processing) ; Nuclear medicine ; Computer science ; Domain (mathematical analysis) ; Radiochemistry ; Physics ; Mathematics ; Algorithm ; Medicine ; Uranium ; Chemistry ; Statistics ; Nuclear physics ; Engineering Radioactive element chemistry and processing ; X-ray Spectroscopy and Fluorescence Analysis ; Nuclear Physics and Applications
Authors: Anchita Addhya | Victor Tyne | Xinghan Guo | Ian Hammock | Zixi Li | M.Y. LEUNG | Clayton DeVault | D. D. Awschalom | Nazar Delegan | F. Joseph Heremans | Alexander A. High
Source: Nano Letters (article, 2024-08-29)
Field: Materials Science — Materials Chemistry

Photonic-Cavity-Enhanced Laser Writing of Color Centers in Diamond Color centers in diamond have widespread utility in quantum technologies, but their creation process remains stochastic in nature. Deterministic creation of color centers in device-ready diamond platforms can improve the yield, scalability, and integration. Recent work using pulsed laser excitation has shown impressive progress in deterministically creating defects in bulk diamond. Here, we extend this laser-writing process into nanophotonic devices etched into diamond membranes, including nanopillars and photonic resonators with writing and subsequent readout occurring in situ at cryogenic temperatures. We demonstrate the optically driven creation of carbon vacancy (GR1) and nitrogen vacancy (NV) centers in diamond nanopillars and observe enhanced photoluminescence collection from them. We also fabricate bullseye resonators and leverage their cavity modes to locally amplify the laser-writing field, yielding defect creation with picojoule write-pulse energies 100 times lower than those typically used in bulk diamond demonstrations. Diamond ; Materials science ; Photoluminescence ; Nanopillar ; Optoelectronics ; Nanophotonics ; Laser ; Photonics ; Vacancy defect ; Nanotechnology ; Resonator ; Optics ; Physics ; Nanostructure Diamond and Carbon-based Materials Research ; Advanced Fiber Laser Technologies ; Laser Material Processing Techniques
Authors: Muntather Almusawi | Aasheesh Shukla | S Hemalatha | P. Kavitha | G.M. Gambhire | Pankaj R. Pardeshi | B. Pragathi
Source: E3S Web of Conferences (article, 2024-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Comparative Analysis of Supercapacitors vs. Batteries This paper presents a comparative analysis of supercapacitors and batteries as energy storage technologies, focusing on key performance metrics such as energy storage capacity, power output, efficiency, and charge/discharge cycles. Supercapacitors are known for their rapid charge and discharge capabilities, high power density, and longevity, making them ideal for applications requiring quick bursts of energy. Conversely, batteries, particularly lithium-ion, offer significantly higher energy density, enabling them to store more energy in a compact form factor, but they suffer from longer charging times and limited cycle life. This study highlights the trade-offs between the two technologies, providing insights into their suitability for various applications, from consumer electronics to renewable energy systems. The findings suggest that while supercapacitors excel in scenarios demanding high power and durability, batteries remain the preferred choice for applications requiring higher energy storage capacity. The analysis underscores the importance of selecting the appropriate energy storage solution based on specific application requirements. Supercapacitor ; Chemistry ; Capacitance ; Electrode Supercapacitor Materials and Fabrication ; Electric and Hybrid Vehicle Technologies ; Advanced Battery Technologies Research
Authors: Sarah J. Zou | Mumukshu D. Patel | Lee M. Smith | Eunho Cha | Sheldon Q. Shi | Wonbong Choi
Source: Materials (article, 2024-06-24)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Pecan Shell-Derived Activated Carbon for High-Electrochemical Performance Supercapacitor Electrode Carbon nanomaterials-based electric double-layer capacitors (EDLCs) are reliable and appealing energy-storage systems offering high power density and long cycling stability. However, these energy storage devices are plagued with critical shortcomings, such as low specific capacitance, inefficient physical/chemical activation process, and self-discharge of electrode materials, hindering their future application. In this work, we use a self-activation process, an environmentally benign and low-cost process, to produce high-performance activated carbon (AC). Novel activated carbon from pecan shells (PS) was successfully synthesized through a single-step self-activation process, which combines the carbonization and activation processes. The as-synthesized pecan shell-derived activated carbon (PSAC) provides a high-porosity, low-resistance, and ordered pore structure with a specific pore volume of 0.744 cm<sup>3</sup>/g and BET surface area of 1554 m<sup>2</sup>/g. The supercapacitors fabricated from PSAC demonstrate a specific capacitance of 269 F/g at 2 A/g, excellent cycling stability over 15,000 cycles, and energy and power density of 37.4 Wh/kg and of 2.1 kW/kg, respectively. It is believed that the high-efficiency PSAC synthesized from the novel self-activation method could provide a practical route to environmentally friendly and easily scalable supercapacitors. Supercapacitor ; Materials science ; Activated carbon ; Capacitance ; Carbonization ; Carbon fibers ; Energy storage ; Power density ; Nanotechnology ; Specific surface area ; Electrode ; Chemical engineering ; Environmentally friendly ; Specific energy ; Electrochemistry ; Composite material ; Chemistry ; Composite number ; Adsorption ; Organic chemistry ; Power (physics) Supercapacitor Materials and Fabrication ; Electrospun Nanofibers in Biomedical Applications ; Advanced Sensor and Energy Harvesting Materials
Authors: Yu Geun Ki | Byeong Je Jeon | Il Hoon Song | Seong Jun Kim | Sangtae Jeon | Soo Jin Kim
Source: ACS Nano (article, 2024-02-19)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Realizing Minimally Perturbed, Nonlocal Chiral Metasurfaces for Direct Stokes Parameter Detection Recent development in nonlocal resonance based chiral metasurfaces draws great attention due to their abilities to strongly interact with circularly polarized light at a relatively narrow spectral bandwidth. However, there still remain challenges in realizing effective nonlocal chiral metasurfaces in optical frequency due to demanding fabrications such as 3D-multilayered or nanoscaled chiral geometry, which, in particular, limit their applications to polarimetric detection with high-Q spectra. Here, we study the underlying working principles and reveal the important role of the interaction between high-Q nonlocal resonance and low-Q localized Mie resonance in realizing effective nonlocal chiral metasurfaces. Based on the working principles, we demonstrate one of the simplest types of nonlocal chiral metasurfaces which directly detects a set of Stokes parameters without the numerical combination of transmitted values presented from typical Stokes metasurfaces. This is achieved by minimally altering the geometry and filling ratio of every constituent nanostructure in a unit cell, facilitating consistent-sized nanolithography for all samples experimentally at a targeted wavelength with relatively high-Q spectra. This work provides an alternative design rule to realizing effective polarimetric metasurfaces and the potential applications of nonlocal Stokes parameters detection. Polarimetry ; Stokes parameters ; Physics ; Nanolithography ; Resonance (particle physics) ; Circular polarization ; Polarization (electrochemistry) ; Nanostructure ; Optics ; Bandwidth (computing) ; Nanotechnology ; Materials science ; Computer science ; Fabrication ; Quantum mechanics ; Scattering ; Chemistry Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Plasmonic and Surface Plasmon Research
Authors: Philipp Hein | Tobias Romstadt | Fabian M. Draber | Jinseok Ryu | Thorben Böger | Andreas Falkenstein | Miyoung Kim | Manfred Martin
Source: Advanced Electronic Materials (article, 2024-11-03)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Variable‐Range Hopping Conduction in Amorphous, Non‐Stoichiometric Gallium Oxide Abstract Amorphous, non‐stoichiometric gallium oxide (a‐GaO x , x &lt; 1.5) is a promising material for many electronic devices, such as resistive switching memories, neuromorphic circuits and photodetectors. So far, all respective measurements are interpreted with the explicit or implicit assumption of n‐type band transport above the conduction band mobility edge. In this study, the experimental and theoretical results consistently show for the first time that for an O/Ga ratio x of 0.8 to 1.0 the dominating electron transport mechanism is, however, variable‐range hopping (VRH) between localized states, even at room temperature and above. The measured conductivity exhibits the characteristic exponential temperature dependence on T −1/4 , in remarkable agreement with Mott's iconic law for VRH. Localized states near the Fermi level are confirmed by photoelectron spectroscopy and density of states (DOS) calculations. The experimental conductivity data is reproduced quantitatively by kinetic Monte Carlo (KMC) simulations of the VRH mechanism, based on the ab‐initio DOS. High electric field strengths F cause elevated electron temperatures and an exponential increase of the conductivity with F 1/2 . Novel results concerning surface oxidation, magnetoresistance, Hall effect, thermopower and electron diffusion are also reported. The findings lead to a new understanding of a‐GaO x devices, also with regard to metal|a‐GaO x Schottky barriers. Variable-range hopping ; Materials science ; Amorphous solid ; Stoichiometry ; Range (aeronautics) ; Gallium oxide ; Thermal conduction ; Oxide ; Gallium ; Condensed matter physics ; Optoelectronics ; Crystallography ; Composite material ; Physical chemistry ; Metallurgy Ga2O3 and related materials ; ZnO doping and properties ; Transition Metal Oxide Nanomaterials
Authors: A. S. Ashik | Peter John Rodrigo | H. Larsen | Nathalia T. Vechi | Konstantinos Kissas | Anders Michael Fredenslund | Jacob Mønster | Charlotte Scheutz | Christian Pedersen
Source: Sensors and Actuators B Chemical (article, 2024-04-21)
Field: Chemistry — Spectroscopy

Integrated-path multi-gas sensor using near-infrared diode lasers: An alternative to vehicle-driven point gas analyzer Sensors for quantitative monitoring of greenhouse gases from high-emission facilities, such as wastewater treatment and industrial plants, are becoming essential to enforce regulatory compliance in climate action initiatives. A predominant sensing technique is the tracer-gas dispersion method (TDM) using closed-path gas analyzers typically installed in a vehicle to measure concentration as the gas plume is transected. Here, we validate for the first time the use of integrated-path gas sensors in TDM, measuring instantaneously the concentration along a predetermined laser beam path, thereby facilitating a stationary setup with orders of magnitude higher update rate and without the need for vehicles or road access. Our approach relies on a sensitive, integrated-path multi-gas sensor for real-time emission quantification using tunable diode laser absorption spectroscopy. An optical sensor head with spectral coverage from 1.52 μm to 1.65 μm is demonstrated, supporting multiplexed gas sensing in a modular fashion using low-power fiber-coupled diode lasers. The sensor measures real-time integrated-path concentrations of CO2 and CH4, and the tracer-gas C2H2 at 130 Hz with 0.5 ppm, 3 ppb, and 2 ppb sensitivity, respectively, at 1 s averaging. The integrated-path sensor is systematically benchmarked for absolute accuracy against a state-of-the-art point sensor, revealing an excellent match over 16 hours. Furthermore, the integrated-path sensor is deployed outdoors for emission quantification using TDM. A comparison to the gold-standard point sensor reveals identical results, demonstrating the integrated-path sensor as a potent substitute for vehicle-driven point sensors. Optical path ; Laser ; Carbon dioxide sensor ; Spectrum analyzer ; Gas analyzer ; Environmental science ; Materials science ; Optics ; Chemistry ; Physics Spectroscopy and Laser Applications ; Atmospheric and Environmental Gas Dynamics ; Air Quality Monitoring and Forecasting
Authors: Amir Mohammadi | Mahsa Parhizgar Keradeh
Source: Heliyon (article, 2024-04-01)
Field: Chemistry — Analytical Chemistry

Exploring the Effect of Relaxation Time, Natural Surfactant, and Potential Determining Ions (Ca2+, Mg2+, and SO42−) on the Dynamic Interfacial Tension Behavior of Model Oil-Brine Systems This study examined how the concentration of asphaltene and divalent ions in various salinities affects the interfacial tension (IFT) between a model oil/brine using the pendant drop method. The oleic phase consisted of a mixture of toluene and n-heptane (heptol), to which asphaltene was added to investigate how asphaltene molecules affect the surface properties. The base fluid was prepared with a salinity of 40,000 ppm, and two additional solutions with concentrations of 4000 ppm (low salinity) and 80,000 ppm (high salinity) were created. The results revealed that increasing the concentration of asphaltene within certain salinity ranges led to a decrease in IFT. The lowest IFT was observed at the 40,000 ppm salinity level, indicating that at this optimal salinity, the maximum asphaltene concentration migrated to the heptol/brine interface, reducing the IFT from 23 mN/m to 16 mN/m. Additionally, a 0.5 % wt of asphaltene demonstrated a significant concentration of micellization of natural surfactants, suggesting that the interface was nearly saturated with asphaltene. Consequently, concentrations higher than this value did not significantly alter the IFT. In the final part of the study, the impact of divalent ions was investigated, revealing that as the concentration of Ca<sup>2+</sup> ions increased up to fourfold, the IFT decreased to 15 mN/m, about 10 % less than the base case. This value represented the lowest IFT compared to Mg<sup>2+</sup> and SO<sub>4</sub><sup>2-</sup>. Moreover, modeling the results indicated that the relaxation time decreased with increasing salinity, suggesting that higher salinity accelerated the process of asphaltene absorption at the interface. Brine ; Pulmonary surfactant ; Surface tension ; Ion ; Chemical engineering ; Thermodynamics ; Chemistry ; Petroleum engineering ; Mineralogy ; Materials science ; Geology ; Engineering ; Physics ; Organic chemistry Petroleum Processing and Analysis ; Hydrocarbon exploration and reservoir analysis ; Enhanced Oil Recovery Techniques
Authors: Fabien Simon | Arnaud Cuisset | Coralie Elmaleh | Francis Hindle | G. Mouret | M. Rey | C. Richard | Vincent Boudon
Source: Physical Chemistry Chemical Physics (article, 2024-01-01)
Field: Chemistry — Spectroscopy

Unrivaled accuracy in measuring rotational transitions of greenhouse gases: THz CRDS of CF<sub>4</sub> Tetrafluoromethane CF<sub>4</sub> is the most abundant perfluorocarbon in the atmosphere, where it is designated as PFC-14. This greenhouse gas is very stable, has an atmospheric lifetime of 50 000 years, and a high greenhouse warming potential 6500 times that of CO<sub>2</sub>. Over the last 15 years, its atmospheric concentration has increased at a rate of 0.8 ppt per year. The accurate quantification of CF<sub>4</sub> is key to understanding the contribution of its emissions to the radiative forcing budget, and the most precise spectroscopic parameters possible are hence required. In this study, a novel high finesse THz cavity, providing an interaction length in excess of 1 km, has enabled highly resolved spectra, and quantification of the weak transitions of CF<sub>4</sub> by cavity ring-down spectroscopy (CRDS). More than 50 pure rotational <i>P</i><sub>6</sub> - <i>P</i><sub>6</sub> : <i>ν</i><sub>3</sub> - <i>ν</i><sub>3</sub> lines of CF<sub>4</sub> have been measured, yielding both position and intensity with unequalled precision. Several tetrahedral splittings are fully resolved and measured with sub-MHz accuracy. Moreover, CRDS-THz allows determining absolute intensities and, using a global fit of the <i>ν</i><sub>2</sub> polyad series, a CF<sub>4</sub> dipole parameter, namely <i></i><sub>3,3</sub>, has been fitted to 106.38(53) mD. This value is in very good agreement with that of the <i>ab initio</i>-based parameter deduced from a dipole moment surface. For the first time, a set of <i>ab initio</i> effective dipole moment parameters is derived for the computation of the transitions of the type <i>P</i><sub><i>n</i></sub> - <i>P</i><sub><i>n</i></sub> (<i>n</i> = 0,…, 8) and the resulting line list composed of 25 863 transitions can be used to model the whole CF<sub>4</sub> rotational spectrum. Finally, the TFMeCaSDa database is updated and is available for future spectroscopic and monitoring activities. Terahertz radiation ; Greenhouse gas ; Chemistry ; Atomic physics ; Analytical Chemistry (journal) ; Physics ; Optoelectronics ; Materials science ; Environmental chemistry ; Biology ; Ecology Spectroscopy and Laser Applications ; Atmospheric Ozone and Climate ; Advanced Chemical Physics Studies
Authors: Amir Hossein Soltan Arani | A. Ghorbanpour Arani | Zahra Khoddami Maraghi
Source: ZAMM ‐ Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik (article, 2024-10-25)
Field: Materials Science — Materials Chemistry

Size‐dependent buckling analysis of functionally graded nanoplate coupled with piezoelectric layers resting on orthotropic foundation based on surface piezo‐elasticity theory Abstract In this study, a refined plate theory by considering stretching effects extended to investigation of quasi‐3D size‐dependent buckling analysis of a functionally graded simply supported nanoplate integrated with piezoelectric face‐sheets resting on orthotropic foundation by taking into account the surface effects. The power law is used to calculate the material properties in the functionally graded core in which the non‐homogeneous core properties are continuously changing along the thickness. Due to the consideration of functionally graded materials and due to the asymmetry in the distribution of material properties in the core, the middle plane and the neutral plane do not coincide. Hence, to consider a reference plane, the concept of a neutral surface is considered. The kinematics of nanoplate are formulated with nonlocal higher order shear deformation theory based on nonlocal strain gradient theory. Additionally, the surface effect is modeled based on surface piezo‐elasticity theory. To check the accuracy and efficiency of the current model, a comprehensive validation and comparative study has been conducted based on the results obtained and the results found in the previous literature. Finally, a comprehensive study is conducted to investigate the effect of various parameters, including different foundations, residual stress, surface effects, stretching effect, neutral surface, aspect ratio, thickness ratio, nanlocal parameter, length scale parameter, gradient index, and initial voltage, which are examined on critical buckling load of nanoplate in details. It is expected that the results of the current study should be utilized in designing micro/nano‐electro‐mechanical systems components based on smart nanostructures. Orthotropic material ; Buckling ; Piezoelectricity ; Foundation (evidence) ; Elasticity (physics) ; Structural engineering ; Materials science ; Surface (topology) ; Composite material ; Finite element method ; Engineering ; Mathematics ; Geometry Nonlocal and gradient elasticity in micro/nano structures ; Composite Structure Analysis and Optimization ; Numerical methods in engineering