Formation Of Hot Spots Research Articles

Greenland 2022 GHOST project: Sampling Greenland geothermal springs - expedition report

This report describes the GRL22 expedition to Disko Island (West Greenland) to sample the thermal springs generated by residual heat associated with formation of the Icelandic hotspot. Despite the large number of springs present on Disko Island, our knowledge of the microbiology of these springs and how they relate to cycling of volatile elements and controls on their budgets is limited. The aim of the project is to understand the diversity of microbial communities brought to Earth’s surface by spring fluids and to determine their role in biogeochemical cycling. The long-term goal of the project is to combine these data with hot spring data from East Greenland and Iceland. This approach will create a transect in “space and time” across the Icelandic hotspot track, that will allow us to evaluate the potential influences of the plume on the subsurface microbial communities. This leg of the expedition took place between July 25 and August 2, 2022, and nine distinct sites were sampled for microbiology and geochemistry.

Surface-Enhanced Raman Scattering Sensors Employing a Nanoparticle-On-Liquid-Mirror (NPoLM) Architecture.

Surface-enhanced Raman scattering (SERS) sensors typically employ nanophotonic structures that support high-field confinement and enhancement in hotspots to increase the Raman scattering from target molecules by orders of magnitude. In general, high field and SERS enhancement can be achieved by reducing the critical dimensions and mode volumes of the hotspots to nanoscale. To this end, a multitude of SERS sensors employing photonic structures with nanometric hotspots have been demonstrated. However, delivering analyte molecules into nanometric hotspots is challenging, and the trade-off between field confinement/enhancement and analyte delivery efficiency is a critical limiting factor for the performance of many nanophotonic SERS sensors. Here, a new type of SERS sensor employing solid-metal nanoparticles and bulk liquid metal is demonstrated to form nanophotonic resonators with a nanoparticle-on-liquid-mirror (NPoLM) architecture, which effectively resolves this trade-off. In particular, this unconventional sensor architecture allows for the convenient formation of nanometric hotspots by introducing liquid metal after analyte molecules are efficiently delivered to the surface of gold nanoparticles. In addition, a cost-effective and reliable process is developed to produce gold nanoparticles on a substrate suitable for forming NPoLM structures. These NPoLM structures achieve two orders of magnitude higher SERS signals than the gold nanoparticles alone.

Johnson–Cook yield functions for cyclotetramethylene-tetranitramine (HMX) and cyclotrimethylene-trinitramine (RDX) derived from single crystal plasticity models

High-fidelity constitutive models are critical for accurate meso-scale continuum modeling and prediction of shock initiation of crystalline energetic materials (EMs). While empirically calibrated or atomistic-guided anisotropic elastoplastic models of EM such as cyclotetramethylene-tetranitramine (HMX) and cyclotrimethylene-trinitramine (RDX) capture important micromechanical phenomena (such as dislocation evolution, slip-resistance, and anisotropic elasticity), the computational cost of using anisotropic single-crystal plasticity models can become prohibitive for meso-scale computations of void-collapse and hotspot formation in microstructures. Thermo-mechanically representative, isotropic, pressure, temperature, and rate-dependent material constitutive models are practical alternatives for meso-scale simulations of the shock response of microstructures. To this end, this work constructs physically consistent isotropic plasticity from anisotropic single-crystal plasticity models for HMX and RDX. State-of-the-art crystal plasticity models for HMX and RDX are used to compute the stress states in single crystals oriented in three different directions relative to shocks generated by impact at velocities ranging from 100 to 1000 m/s. Post-shock von Mises stress fields for the three orientations are then used to calibrate the strain-rate hardening coefficient and the reference strain rate for a rate-dependent Johnson–Cook (JC) yield surface model. We compare the pressures and the post-shock von Mises stresses between the JC and the anisotropic models to show that the isotropic computations closely approximate the averaged deformation response of the three different crystal orientations. We then model the interaction of a shock generated by a 500 m/s impact with a 0.5 μm void and show that the pressures and the deviatoric stresses obtained using the isotropic model closely match those computed from anisotropic models for both HMX and RDX. The resulting isotropic J2 plastic flow model for HMX and RDX can be employed to perform meso-scale simulations for energy localization due to shear bands and void collapse in the two materials.

Short-term effect of liquid organic fertilisation and application methods on N2, N2O and CO2 fluxes from a silt loam arable soil

AbstractThe absence of N2 flux measurements in liquid manure-amended soils has resulted in a poor understanding of the effect of manure application on gaseous N losses. The aim of this study was to quantify N2, N2O, CO2, N2O reduction to N2, depth distribution of moisture, water-extractable organic C, NO3−, NH4+, pH, and diffusivity in a laboratory incubation experiment with an arable silt-loam soil. To quantify N processes and gaseous fluxes, 15N tracing was applied. An artificial livestock slurry-mixture was added to the soil in various treatments (control, surface or injected application; slurry-application rate: 42.9 kg N ha− 1; soil water content of either 40% or 60% water-filled pore space (WFPS)). The soil was incubated for 10 days. The depth distribution of the control parameters was measured twice during the experiment on days 5 and 10. The average increase in N2 and N2O fluxes from denitrification was about 900% in slurry-amended soils. The highest N2 and N2O fluxes from denitrification were measured in the slurry injection, 60% WFPS treatment (7.83 ± 3.50 and 11.22 ± 7.60 mg N m− 2 d− 1, respectively). The hypothesis that injected slurry at a higher water content enhances denitrification was confirmed. This study provides important insights into the formation, spatial and temporal variation of the manure-soil hotspot and its impact on the denitrification process. The results will form part of a dataset to develop, improve and test manure application submodules of biogeochemical models and will help to understand in detail the effect of hotspots on N-cycling in manure-treated soils.

Roles of Hydrology and Transport Processes in Denitrification at Watershed Scale

AbstractRainfall runoff and leaching are the main driving forces that nitrogen, an important non‐point source (NPS) pollutant, enters streams, lakes, and groundwater. Hydrological and transport processes thus play a pivotal role in NPS nitrogen pollution. Existing hydro‐environmental models for nitrogen pollution often over‐simplify the within‐watershed processes. It is unclear how such simplification affects the pollution assessment regarding the formation and distribution of denitrification hot spots—which is important for the design of land‐based countermeasures. To study this problem, we developed a model, DHSVM‐N, and its variant, DHSVM‐N_alt. DHSVM‐N is developed by integrating nitrogen‐related processes of SWAT into a comprehensive process‐based hydrological model, the Distributed Hydrology Soil and Vegetation Model (DHSVM). DHSVM‐N includes detailed representations of nitrate transport process at a fine spatial resolution with good landscape connectivity to accommodate interactions between hydrological and biogeochemical processes along the flow travel pathways. Because of the lack of spatially distributed observational data for validation, a model‐to‐model comparison study is conducted. Through comparison studies on a representative catchment using SWAT, DHSVM‐N and DHSVM‐N_alt, we quantify the critical roles of hydrological processes and nitrate transport processes in modeling the denitrification process. That is, the capabilities to give reasonable soil moisture estimates and to account for essential processes that take place along flow pathways are keys to simulate denitrification hot spots and their spatial variation. Furthermore, DHSVM‐N results show that terrestrial denitrification from hotspots alone can reach as high as 36% of the annual stream nitrate export of the watershed.

Variation of the shapes of catalytic blocks in the autothermal reforming of hexadecane, propane and methane using mathematical modeling

In this work, mathematical modeling of the autothermal reforming of hexadecane, propane and methane on catalytic blocks of different geometric shapes was carried out. It was shown that the convex shape of the block towards the oncoming reaction flow can increase the maximum temperature in the frontal zone, while the concave shape contributes to a more uniform temperature distribution along the entire length of the catalytic layer. The work also investigated the effect of the reaction flow rate on the change in the temperature gradient, which can subsequently be used to prevent the formation of hot spots and catalyst deactivation. The results obtained can serve as the basis for future research in the field of autothermal reforming and optimization of the geometric parameters of catalysts for the conversion of hydrocarbon fuels into synthesis gas.

Onward Spread from Liver Metastases Is a Major Cause of Multi-Organ Metastasis in a Mouse Model of Metastatic Colon Cancer.

Colorectal cancer metastasizes predominantly to the liver but also to the lungs and the peritoneum. The presence of extra-hepatic metastases limits curative (surgical) treatment options and is associated with very poor survival. The mechanisms governing multi-organ metastasis formation are incompletely understood. Here, we tested the hypothesis that the site of tumor growth influences extra-hepatic metastasis formation. To this end, we implanted murine colon cancer organoids into the primary tumor site (i.e., the caecum) and into the primary metastasis site (i.e., the liver) in immunocompetent mice. The organoid-initiated liver tumors were significantly more efficient in seeding distant metastases compared to tumors of the same origin growing in the caecum (intra-hepatic: 51 vs. 40%, p = 0.001; peritoneal cavity: 51% vs. 33%, p = 0.001; lungs: 30% vs. 7%, p = 0.017). The enhanced metastatic capacity of the liver tumors was associated with the formation of 'hotspots' of vitronectin-positive blood vessels surrounded by macrophages. RNA sequencing analysis of clinical samples showed a high expression of vitronectin in liver metastases, along with signatures reflecting hypoxia, angiogenesis, coagulation, and macrophages. We conclude that 'onward spread' from liver metastases is facilitated by liver-specific microenvironmental signals that cause the formation of macrophage-associated vascular hotspots. The therapeutic targeting of these signals may help to contain the disease within the liver and prevent onward spread.

Stability Challenges for a Highly Efficient Perovskite/Silicon Tandem Solar Cell: A Review

As the balance of system cost of photovoltaic (PV) installations governs the competitiveness of PV device market, next‐generation solar cells desire substantially enhanced power conversion efficiencies (PCEs). The single‐junction perovskite and Si solar cells have demonstrated PCEs beyond 26% and 25%, respectively. The tandem configuration has crossed the threshold posed by the shockley queisser limit by demonstrating the 33.9% PCE. However, the unresolved issues in the perovskite community from a stability perspective pose challenges for realizing highly efficient and stable perovskite–Si tandem solar cells (TSCs). This review highlights the current status of perovskite–Si TSC from a stability perspective besides elucidating the degradation mechanisms at the perovskite–Si at the cell and module level. A highly efficient perovskite–Si TSC needs optimization keeping view the specific requirements for tandem configuration like strain, current matching, and bandgap optimization between the top perovskite and bottom Si subcell. Various stressors affecting the efficiency of the perovskite–Si module, namely, reverse bias and hot spot formation, and delamination, highlight valuable insight to develop future strategies for the perovskite–Si TSC. Stability regimes for the single‐junction perovskite solar cell can provide the essential stepping stone but, modified stability regimes are inevitable.

SPH code development for X-pinch plasma simulation

We have developed the first smoothed particle hydrodynamics code for investigating X-pinch plasmas driven by pulsed power generators. To achieve the required code performance, we incorporated and discussed appropriate physics models capable of simulating the X-pinch phenomenon across various domains, encompassing equation of state, plasma transport, and radiation effects. The simulations were conducted in full three dimensions using our newly developed code, and we have compared and evaluated the results with experimental data obtained from the X-pinch device at Seoul National University. As a result, our simulations effectively captured the implosion behavior of X-pinch plasma, faithfully reproducing the four-step evolution process commonly observed in typical X-pinch configurations. Furthermore, it provided comprehensive spatiotemporal data on various plasma parameters, including density, temperature, velocity field, and radiated power. Notably, the electron temperature and density at the hot spot well agree with the experimental measurements, validating the accuracy and reliability of the developed simulation code. Additionally, the radiation data exhibited significantly improved accuracy compared to previous simulation results, confirming the effectiveness of the proposed radiation model, and it provides valuable insights into the X-pinch hot spot formation.

Evaluation of green banana pulp drying using infrared radiation with temperature control

The green banana flour (GBF) is a functional food rich in resistant starch and nutrients, probiotic, and has low glycemic index. The obtaining of the flour is usually done in dryers with high energy consumption, and possible deteriorating processes. These problems can be minimized with an adaptive temperature control system in infrared heat sources. The aim of this research was to quantify the energy savings in the production of green banana flour produced by infrared drying compared to the conventional process of drying in a resistance oven. The production of flour from green banana pulp was evaluated using an infrared radiation dryer with fruit surface temperature control (IR-FSTC). The IR-FSTC was performed by keeping the pulp surface at 50 °C and 60 °C. The results were compared with conventional drying using a resistive source. The energy consumption of drying using IR-FSTC was significantly reduced compared to the drying by resistive source and prevented the formation of hotspots. The drying process was also evaluated by physicochemical and spectroscopic analyses of the GBF. The product maintained the pH, titratable acidity, total soluble solids, and lipid content with values similar to those obtained by conventional heating oven drying. In turn, the spectroscopic analyses confirmed the maintenance of biomolecules inherent in GBF. Thus, it is concluded that the results contribute to the sustainable use of energy resources in the production of GBF.

Homoeologous exchanges contribute to branch angle variations in rapeseed: Insights from transcriptome, QTL-seq and gene functional analysis.

Branch angle (BA) is a critical morphological trait that significantly influences planting density, light interception and ultimately yield in plants. Despite its importance, the regulatory mechanism governing BA in rapeseed remains poorly understood. In this study, we generated 109 transcriptome data sets for 37 rapeseed accessions with divergent BA phenotypes. Relative to adaxial branch segments, abaxial segments accumulated higher levels of auxin and exhibited lower expression of six TCP1 homologues and one GA20ox3. A co-expression network analysis identified two modules highly correlated with BA. The modules contained homologues to known BA control genes, such as FUL, YUCCA6, TCP1 and SGR3. Notably, a homoeologous exchange (HE), occurring at the telomeres of A09, was prevalent in large BA accessions, while an A02-C02 HE was common in small BA accessions. In their corresponding regions, these HEs explained the formation of hub gene hotspots in the two modules. QTL-seq analysis confirmed that the presence of a large A07-C06 HE (~8.1 Mb) was also associated with a small BA phenotype, and BnaA07.WRKY40.b within it was predicted as candidate gene. Overexpressing BnaA07.WRKY40.b in rapeseed increased BA by up to 20°, while RNAi- and CRISPR-mediated mutants (BnaA07.WRKY40.b and BnaC06.WRKY40.b) exhibited decreased BA by up to 11.4°. BnaA07.WRKY40.b was exclusively localized to the nucleus and exhibited strong expression correlations with many genes related to gravitropism and plant architecture. Taken together, our study highlights the influence of HEs on rapeseed plant architecture and confirms the role of WRKY40 homologues as novel regulators of BA.

Effect of shock impedance of mesoscale inclusions on the shock-to-detonation transition in liquid nitromethane

Two-dimensional, meso-resolved numerical simulations are performed to investigate the effect of shock impedance of mesoscale inclusions on the shock-to-detonation transition (SDT) in liquid nitromethane (NM). The shock-induced initiation behaviors resulting from the cases with NM mixed with randomly distributed, 100-μm-sized air-filled cavities, polymethyl methacrylate (PMMA), silica, aluminum (Al), and beryllium (Be) particles with various shock impedances are examined. In this paper, hundreds of inclusions are explicitly resolved in the simulation using a diffuse-interface approach to treat two immiscible fluids. Without using any empirically calibrated, phenomenological models, the reaction rate in the simulations only depends on the temperature of liquid NM. The sensitizing effect of different inclusion materials can be rank-ordered from the weakest to the strongest as PMMA → silica → air → Al → Be in the hot-spot-driven regime of SDT. Air-filled cavities have a more significant sensitizing effect than silica particles, which is in agreement with the experimental finding. For different solid-phase inclusions, hot spots are formed by Mach reflection upon the interaction between the incident shock wave and the particle. The sensitizing effect increases roughly with the shock impedance of the inclusion material. More details of the hot-spot formation process for each solid-phase inclusion material are revealed via zoom-in simulations of a shock passing over a single particle.

Quantum Gas-Enabled Direct Mapping of Active Current Density in Percolating Networks of Nanowires.

Electrically percolating nanowire networks are among the most promising candidates for next-generation transparent electrodes. Scientific interest in these materials stems from their intrinsic current distribution heterogeneity, leading to phenomena like percolating pathway rerouting and localized self-heating, which can cause irreversible damage. Without an experimental technique to resolve the current distribution and an underpinning nonlinear percolation model, one relies on empirical rules and safety factors to engineer materials. We introduce Bose-Einstein condensate microscopy to address the longstanding problem of imaging active current flow in 2D materials. We report on performance improvement of this technique whereby observation of dynamic redistribution of current pathways becomes feasible. We show how this, combined with existing thermal imaging methods, eliminates the need for assumptions between electrical and thermal properties. This will enable testing and modeling individual junction behavior and hot-spot formation. Investigating both reversible and irreversible mechanisms will contribute to improved performance and reliability of devices.

Improving microwave heating uniformity of spherical objects by wrapping optimized dielectrics

As a green and efficient heating technology, microwave heating has shown its superiority in many fields. However, hot spots widely exist when heating spherical objects which may lead to overheated damages. In this work, a method of designing dielectrics for wrapping spherical objects is proposed to reduce hot spots in microwave heating. Firstly, a comprehensive model based on the geometrical optics is proposed to analyze the hot spot formation in the spherical object. Secondly, a multi-physics model based on the finite element method is built to simulate the heating process of the spherical object wrapped by the dielectric in an electrically large cavity with moving elements. The optimal shape and relative permittivity of the dielectric are determined by the simulations. Finally, a cuboid alumina ceramic with a dimension of 70 mm × 80 mm × 150 mm and a relative permittivity of 9.2 is customized according to the simulation results to wrap the spherical object. The experiment results measured in a practical microwave heating system are in good agreement with the simulation results. Both the simulation and experiment show that the proposed method can efficiently reduce the hot spot and significantly improve the heating uniformity.

Immune-like sandwich multiple hotspots SERS biosensor for ultrasensitive detection of NDKA biomarker in serum

Developing the rapid, specific, and sensitive tumor marker NDKA biosensor has become an urgent need in the field of early diagnosis of colorectal cancer (CRC). Surface-enhanced Raman spectroscopy (SERS) with the advantages of high sensitivity, high resolution as well as providing sample fingerprint, enables rapid and sensitive detection of tumor markers. However, many SERS biosensors rely on boosting the quantity of Raman reporter molecules on individual nanoparticle surfaces, which can result in nanoparticle agglomeration, diminishing the stability and sensitivity of NDKA detection. Here, we proposed an immune-like sandwich multiple hotspots SERS biosensor for highly sensitive and stable analysis of NDKA in serum based on molecularly imprinted polymers and NDKA antibody. The SERS biosensor employs an array of gold nanoparticles, which are coated with a biocompatible polydopamine molecularly imprinted polymer as a substrate to specifically capture NDKA. Then the biosensor detects NDKA through Raman signals as a result of the specific binding of NDKA to the SERS nanotag affixed to the capture substrate along with the formation of multiple hotspots. This SERS biosensor not only avoids the aggregation of nanoparticles but also presents a solution to the obstacles encountered in immune strategies for certain proteins lacking multiple antibody or aptamer binding sites. Furthermore, the practical application of the SERS biosensor is validated by the detection of NDKA in serum with the lower limit of detection (LOD) of 0.25 pg/mL, meanwhile can detect NDKA of 10 ng/mL in mixed proteins solution, illustrating high sensitivity and specificity. This immune-like sandwich multiple hotspots biosensor makes it quite useful for the early detection of CRC and also provides new ideas for cancer biomarker sensing strategy in the future.

Low energy ion irradiation induced Au/Ag multilayer nanostructured substrates for SERS-based molecular sensing

Au and Ag are the most prominent plasmonic materials to study Surface-Enhanced Raman Spectroscopy (SERS) because of their wide tuning of localized surface plasmon resonance in the broad wavelength range. In the present work, the formation of nanostructures of Au single-layer, Au/Ag bi-layer, and Au/Ag/Au/Ag four-layer thin films on silicon substrates by low energy Kr++ ion irradiation with fluences of 1 × 1015 and 3 × 1015 ions/cm2 was systematically studied and were used for the detection of dye molecules. The surface morphology and microstructural analysis indicated the formation of different nanostructures with different ion fluences by atomic force microscopy and field emission scanning electron microscopy. Rutherford backscattering spectrometry results indicate a considerable change in film thickness after ion irradiation, mainly due to the removal of surface atoms due to sputtering. The maximum enhancement in Raman intensity of R6G was observed in the Bi-layer Au–Ag substrate compared to other substrates with an enhancement factor of 4.78 × 106 corresponding to a 1516 cm−1 characteristic peak in SERS analysis. Coumarin 343 molecules trace amount were detected to determine the versatility of the substrate. A finite-difference time-domain simulation was performed to provide a better understanding of the nanostructure hot-spots formation and support the obtained SERS results.

Reactive molecular dynamics simulations on the hotspot formation and pyrolysis mechanisms of TNBI/TANPDO cocrystal: Effects of defects with different nano-void sizes

The effects of void defect sizes on the hotspot formation and pyrolysis mechanism of high-energy cocrystal 4,40,5,50-tetranitro-2,20-bi-1H-imidazole/ 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (TNBI/TANPDO) were quantitatively assessed by ReaxFF-lg molecular dynamics simulations. Nano-size defects can...

Formation of fast-ignition hotspots and propagartion of burning waves in pre-compressed isochoric plasmas

The formation and evolution of hotspots is important for achieving ignition and high energy gain in inertial fusion process. However, most of relevant studies are carried out on pre-compressed plasmas with an isobaric configuration, the evolution of the hotspot in a plasma with an isochoric configuration is rarely studied. In this paper, a semi-analytical model is developed to describe the evolution of the hotspot boundary and propagation of fusion burning waves for a high-density pre-compressed plasma with an isochoric configuration in the double-cone ignition scheme. For the shock wave, the strong shock wave approximation and the quasi-isobaric approximation are reasonable. The quasi-isobaric approximation shows that as the plasma density behind the shock wave increases, the plasma temperature decreases. Because of these, the range of <inline-formula><tex-math id="M4">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.png"/></alternatives></inline-formula>-particles decreases rapidly behind the shock wave, forming an <inline-formula><tex-math id="M5">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.png"/></alternatives></inline-formula>-particle absorption peak. Therefore, considering that the hotspot is the main region where <inline-formula><tex-math id="M6">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.png"/></alternatives></inline-formula>-particles are produced and deposited, the position of the shock peak can be used to identify the boundary of the hotspot in a high-density plasma with an isochoric configuration. It also shows that a “self-regulating burning process” exists in the burning process of the isochoric hotspot, most of <inline-formula><tex-math id="M7">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.png"/></alternatives></inline-formula>-particles are deposited in the stable region and behind the shock, and finally, transport through the shock peak and heat the cold fuel, resulting in the temperature rising. In the high-density hotspots of plasma with an isochoric configuration, the deposition of α-particles behaves as an obvious non-uniform distribution effect. By analyzing the non-uniform deposition of α-particles, the deposition rate of α-particles at the edge of spherical uniform hotspot is calculated, then the temperature and density evolution of the isochoric hotspot can be well described. The model can be used to estimate the Lawson parameter of the hotspots at the end of the early stage of ignition. It is found that a lower fast electron energy is more beneficial to ignition and high gain operation of fusion plasma. It is also shown that the high density of the hotspots in the isochoric plasma will lead to a higher fusion burning rate, which can offset the negative influence of the shock wave and even achieve higher energy gain. The semi-analytical model is verified by the hydrodynamic simulations of O-SUKI-N.

The Interplay between Protein Frustration and Hotspot Formation

Hotspots situated at protein-protein interfaces, allosteric and orthosteric binding sites, traditionally play a crucial role in the initial phases of drug discovery, as they are useful to identify druggable targets and guide the optimization of fragments into lead compounds. Despite the high level of protein frustration, which can be thought of as the percentage of residues that cannot independently achieve minimum energy due to tridimensional restraints, observed at those locations, limited efforts have been made to investigate any potential connection between the localized frustration and hotspots in proteins. This review paper aims to partially address this knowledge gap by proposing that the origin of hotspots is, at least in part, due to localized frustration in proteins. While there is no hard evidence to support this hypothesis, the results obtained by integrating in silico tools predicting hot spot locations, with those calculating localized protein frustration, suggest that druggable hotspots are surrounded by residues involved in frustrated contacts. Additionally, the inclusion of long-range electrostatic terms in the protein frustration calculation enables the identification of an equal to a higher number of frustrated residues. These observations indirectly suggest that localized protein frustration around druggable hotspots could guide the development of more potent leads.

Methodology and Instrumentation Development for a Solar Module Diagnosing System in a Remote Mode under Non-Uniform Illuminaion

The monitoring principle of the solar module conditions as a part of photovoltaic power plants is considered. In the existing monitoring technology, information about the electrical parameters of individual solar modules being the part of linear chains gets lost. If a fault is not detected and corrected in a timely manner, energy production is reduced and the risk of local hot spot formation in the photovoltaic converters that make up the solar modules increases. The technical task is to equip the solar module with a diagnostic unit simple in design and capable to detect a violation of the normal operating mode automatically. A system for diagnosing solar modules in a remote mode has been developed, which determines the presence of current in the bypass diode circuit being the violation of the normal operation mode of the module. The current sensor (based on the Hall effect) detects the presence of current in the bypass diode circuit (i.e., current flowing bypassing a group of solar cells located at reduced illumination). This installation makes it possible to detect electric current in the bypass diode circuit, where it should not exist during normal operation, which is a consequence of the fact that the solar module group of solar cells shunted by this bypass diode has stopped generating electric current, due to the fact that the illumination of one or several PV cells in this group became lower than the PV illumination in other groups of the solar module. The diagnostic unit operates as part of a wireless sensor network. Each wireless diagnostic unit has a unique address, thanks to which it is possible to determine the coordinates of a module that is operating intermittently. The technical result is to simplify the design, increase the reliability of the solar module, and reduce the time for localizing the “problem module”.