Field Hot Spots Research Articles

Hierarchically Enhanced Plasmonic Absorber with Abundant Nanomirrors for Effective Photoelectrochemical Performance

The synergistic combination of plasmonic metals and semiconductors demonstrates marvelous potential for nanocomposite design, particularly in enhancing photoelectrochemical performance through rich interfacial modifications and component properties adjustments. In terms of it, nanocomplexes of metal/insulator or semiconductor/metal have emerged heatedly, commonly depicted as nanomirror structures. In this work, a sandwiched nanomirror structure comprising a core Ag nanorods, a TiO2 middle nanogap, and dual types of Au and Ag particles outermost is presented, putting forward a novel design idea of rolling the planar complex up to amplify the potential interaction systems. The TiO2 middle layer enables the intrinsic generation of charge carriers upon light exposure, while the established heterojunctions promote their efficient separation. Additionally, both the inner Ag NRs and outer metal nanoparticles exhibit localized surface plasma resonance effects to realize enhancement of electric fields, where plasmonic coupling between them generates field hotspots within TiO2 layer, thereby expanding light absorption range and enhancing light capture intensity. Beyond, hot electrons from plasmonic metals traverse Schottky barriers into TiO2 to participate in further reactions, all of which contribute to heightened PEC performance of the nanostructure. In this work, the path is paved for innovative nanostructure design integrating plasmonic metals with semiconductors, offering promising implications for energy‐related applications.

Research on acoustic temperature field hotspot tracking based on RBFNN adaptive grid

Research on acoustic temperature field hotspot tracking based on RBFNN adaptive grid

Nanocavity-based single-molecule plasmon-enhanced Raman spectroscopy: Features and advancements.

Since 1997, driven by advancements in nanoscience, single-molecule plasmon-enhanced Raman spectroscopy (SM-PERS) has developed into a powerful technique for ultrasensitive trace analysis through fingerprint vibrational chemical information. The nanocavity between the coupled plasmonic nanostructures, offering an exceptionally high Raman signal enhancement factor (i.e., plasmonic field hotspot), is crucial for the achievement of SM-PERS. Herein, we first briefly review the development of SM-PERS, followed by an introduction of the features and methodologies of SM-PERS, as well as the applications of SM-PERS in biological analysis, high-resolution chemical imaging, and the investigations of single-molecule reactions. Finally, a perspective highlighting the advancement of new methods and applications of nano-driven SM-PERS is presented.

Dynamically controllable hot spots in DNA-derived hydrogel scaffold SERS substrate for exosome recognition using DNA self-assembly amplification

In the context of surface-enhanced Raman scattering (SERS) applications, an effective active substrate is supposed to exhibit a high enhancement factor, long-term stability, and excellent repeatability, as well as allow target molecules to enter the hot spot area with adequate quantity and affinity. The electromagnetic field in hot spots can be drastically amplified and results in an extraordinary large signal enhancement. However, uncontrolled formation of hot spots has hampered the realization of this intention. Here, we reported an innovative SERS active substrate, named as DNA-derived dynamic hydrogel scaffold (DDHS), which is endowed with the robust electromagnetic enhancement and exceptional target affinity. Based on this integrated microfluidic chip, rationally designed DNA oligonucleotides were introduced to recognize exosome indicator-CD63, which achieved a limit of 2.63 particles μL−1. Taken together, we believed that the proposed strategy would be possible to accelerate SERS applied to trace detection of tumor biomarkers, thus offering a promising route toward screening test and early diagnostic of cancerdiseases.

Surface-Enhanced Infrared Absorption Spectroscopy by Resonant Vibrational Coupling with Plasmonic Metal Oxide Nanocrystals.

Coupling between plasmonic resonances and molecular vibrations in nanocrystals (NCs) offers a promising approach for detecting molecules at low concentrations and discerning their chemical identities. Metallic NC superlattices can enhance vibrational signals under far-field detection by generating a myriad of intensified electric field hot spots between the NCs. Yet, their effectiveness is limited by the fixed electron concentration dictated by the metal composition and inefficient hot spot creation due to the large mode volume. Doped metal oxide NCs, such as tin-doped indium oxide (ITO), could overcome these limitations by enabling broad tunability of resonance frequencies in the mid-infrared range through independent variation of size and doping concentration. This study investigates the potential of close-packed ITO NC monolayers for surface-enhanced infrared absorption by quantifying trends in the coupling between their plasmon modes and various molecular vibrations. We show that maximum vibrational signal intensity occurs in monolayers composed of larger, more highly doped NCs, where the plasmon resonance peak lies at higher frequency than the molecular vibration. Using finite element and mutual polarization methods, we establish that near-field enhancement is stronger on the low-frequency side of the plasmon resonance and for more strongly coupled plasmonic NCs, thus rationalizing the design rules we experimentally uncovered. Our results can guide the development of optimal metal oxide NC-based superstructures for sensing target molecules or modifying their chemical properties through vibrational coupling.

Monodispersed mesoscopic star-shaped gold particles via silver-ion-assisted multi-directional growth for highly sensitive SERS-active substrates

Surface-enhanced Raman scattering (SERS) exploits localized surface plasmon resonances in metallic nanostructures to significantly amplify Raman signals and perform ultrasensitive analyses. A critical factor for SERS-based analysis systems is the formation of numerous electromagnetic hot spots within the nanostructures, which represent regions with highly concentrated fields emerging from excited localized surface plasmons. These intense hotspot fields can amplify the Raman signal by several orders of magnitude, facilitating analyte detection at extremely low concentrations and highly sensitive molecular identification at the single-nanoparticle level. In this study, mesoscopic star-shaped gold particles (gold mesostars) were synthesized using a three-step seed-mediated growth approach coupled with the addition of silver ions. Our study confirms the successful synthesis of gold mesostars with numerous sharp tips via the multi-directional growth effect induced by the underpotential deposition of silver adatoms (AgUPD) onto the gold surfaces. The AgUPD process affects the nanocrystal growth kinetics of the noble metal and its morphological evolution, thereby leading to intricate nanostructures with high-index facets and protruding tips or branches. Mesoscopic gold particles with a distinctive star-like morphology featuring multiple sharp projections from the central core were synthesized by exploiting this phenomenon. Sharp tips of the gold mesostars facilitate intense localized electromagnetic fields, which result in strong SERS enhancements at the single-particle level. Electromagnetic fields can be further enhanced by interparticle hot spots in addition to the intraparticle local field enhancements when arranged in multilayered arrays on substrates, rendering these arrays as highly efficient SERS-active substrates with improved sensitivity. Evaluation using Raman-tagged analytes revealed a higher SERS signal intensity compared to that of individual mesostars because of interparticle hot spots enhancements. These substrates enabled analyte detection at a concentration of 10− 9 M, demonstrating their remarkable sensitivity for trace analysis applications.

Evaluation of Applicability of Tumor Budding and Poorly Differentiated Clusters as Additional Prognostic Markers in Colorectal Cancers

Purpose Very few studies have assessed tumor budding (TB) and poorly differentiated cell clusters (PDCs) simultaneously in colorectal cancers (CRCs). The goal of this study was to establish a correlation between these two pertinent histological features and to reinforce the importance of their incorporation in routine histopathological reporting of CRC cases as a means to predict clinical outcome. Methods Resection specimens of colorectal carcinoma were included in the study. Patients who received presurgical therapy, or refused consent were excluded. PDC and TB were evaluated in routine hematoxylin and eosin-stained histopathological sections taken from the advancing edge of the tumor. TB and PDC were reported by selecting a “hotspot” chosen after review of all available slides with invasive tumor. It was then followed by their correlation with other known prognostic factors. Results Spearman's rho calculator for strength of association between TB and PDC as well as association of TB and PDC individually with known prognostic factors revealed statistical significance. Correlation of TB and PDC with histologic grade, primary tumor (pT), and regional lymph node (pN) stage was done based on one-way analysis of variance calculator, which yielded statistically significant results. Conclusion Evaluation of these two histological parameters in the same hotspot field at the tumor invasive front plays a fundamental role in the definition of cancer aggressiveness and prediction of tumor behavior.

The Feasibility of Positioning Electromagnetic Near Field Hotspots within a Resonant Cavity for Microwave Thermal Ablation

The Feasibility of Positioning Electromagnetic Near Field Hotspots within a Resonant Cavity for Microwave Thermal Ablation

Quantification of soil erosion and sediment yield using the RUSLE model in Boyo watershed, central Rift Valley Basin of Ethiopia

Changes in land use and land cover (LULC) are becoming recognized as critical to sustainability research, particularly in the context of changing landscapes. Soil erosion is one of the most important environmental challenges today, particularly in developing countries like Ethiopia. The objective of this study was evaluating the dynamics of soil loss, quantifying sediment yield, and detecting soil erosion hotspot fields in the Boyo watershed. To quantify the soil erosion risks, the Revised Universal Soil Loss Equation (RUSLE) model was used combined with remote sensing (RS) and geographic information system (GIS) technology, with land use/land cover, rainfall, soil, and management approaches as input variables. The sediment yield was estimated using the sediment delivery ratio (SDR) method. In contrast to a loss in forest land (1.7 %), water bodies (3.0 %), wetlands (1.5 %), and grassland (1.7 %), the analysis of LULC change (1991–2020) showed a yearly increase in the area of cultivated land (1.4 %), built-up land (0.8 %), and bare land (3.5 %). In 1991, 2000, and 2020, respectively, the watershed's mean annual soil loss increases by 15.5, 35.9, and 38.3 t/ha/y. Approximately 36 cm of the watershed's economically productive topsoil was lost throughout the study's twenty-nine-year period (1991–2020). According to the degree of erosion, 16 % of the watershed was deemed seriously damaged, while 70 % was deemed slightly degraded. Additionally, it is estimated for the year 2020 that 74,147.25 t/y of sediment (8.52 % of the total annual soil loss of 870,763.12 t) reach the Boyo watershed outlet. SW4 and SW5 were the two sub-watersheds with the highest erosion rates, requiring immediate conservation intervention to restore the ecology of the Boyo watershed.

Global trends and performances of infrared imaging technology studies on acupuncture: a bibliometric analysis.

To summarize development processes and research hotspots of infrared imaging technology research on acupuncture and to provide new insights for researchers in future studies. Publications regarding infrared imaging technology in acupuncture from 2008 to 2023 were downloaded from the Web of Science Core Collection (WoSCC). VOSviewer 1.6.19, CiteSpace 6.2.R4, Scimago Graphica, and Microsoft Excel software were used for bibliometric analyses. The main analyses include collaboration analyses between countries, institutions, authors, and journals, as well as analyses on keywords and references. A total of 346 publications were retrieved from 2008 to 2023. The quantity of yearly publications increased steadily, with some fluctuations over the past 15 years. "Evidence-Based Complementary and Alternative Medicine" and "American Journal of Chinese Medicine" were the top-cited journals in frequency and centrality. China has the largest number of publications, with the Shanghai University of Traditional Chinese Medicine being the most prolific institution. Among authors, Litscher Gerhard from Austria (currently Swiss University of Traditional Chinese Medicine, Switzerland) in Europe, was the most published and most cited author. The article published by Rojas RF was the most discussed among the cited references. Common keywords included "Acupuncture," "Near infrared spectroscopy," and "Temperature," among others. Explore the relationship between acupoints and temperature through infrared thermography technology (IRT), evaluate pain objectively by functional near-infrared spectroscopy (fNIRS), and explore acupuncture for functional connectivity between brain regions were the hotspots and frontier trends in this field. This study is the first to use bibliometric methods to explore the hotspots and cutting-edge issues in the application of infrared imaging technology in the field of acupuncture. It offers a fresh perspective on infrared imaging technology research on acupuncture and gives scholars useful data to determine the field's hotspots, present state of affairs, and frontier trends.

Bibliometric analysis of emerging trends and research foci in brainstem tumor field over 30years (1992-2023).

Over the past several decades, numerous articles have been published on brainstem tumors. However, there has been limited bibliometric analysis in this field. Therefore, we conducted a bibliometric analysis to elucidate the evolution and current status of brainstem tumor research. We retrieved 5525 studies published in English between 1992 and 2023 from the Web of Science Core Collection database. We employed bibliometric tools and VOSviewer to conduct the analysis. We included a total of 5525 publications for further analysis. The annual publications have exhibited steady growth over time. The United States accounted for the highest number of publications and total citations. Among individual researchers, Liwei Zhang had the highest number of publications, while Cynthia Hawkins and Chris Jones shared the most citations, closely followed by Eric Bouffet in this field. The study titled "Diffuse brainstem glioma in children: critical review of clinical trials" stood out as the most cited work in this field. Keyword analysis revealed that immune therapy and epigenetic research are the focal points of this field. Our bibliometric analysis underscores the enduring significance of brainstem tumors in the realm of neuro-oncology research. The field's hotspots have transitioned from surgery and radiochemotherapy to investigating epigenetic mechanisms and immune therapy.

Stem-like CD8 T cells in stage I lung adenocarcinoma as a prognostic biomarker: A preliminary study.

This study aimed to investigate the presence of stem-like CD8 T (CD8 TSL) cells in lung adenocarcinoma (LUAD) and explore their relationships with the clinical outcomes. Multiplex immunofluorescence (mIF) was performed to identify CD8 TSL and antigen-presenting cells (APC) in 76 LUAD patients. Differences in the number of CD8 TSL cells based on tumor stage and the spatial relationships between CD8 TSL cells and APC niches were determined. The optimal cutoff value of CD8 TSL cells for predicting survival in patients with stage I LUAD was calculated. CD8 TSL cells were present in all tumors, and their numbers were significantly higher in stage I patients than in stage III patients (P = 0.010); CD8 TSL cells located in the APC niches accounted for 69.7% (53/76) of the hotspot fields. The optimal cutoff value for the number of CD8 TSL cells required to predict the overall survival (OS) in patients with stage I LUAD was 2.5 per 10000 μm2. The median OS and progression-free survival (PFS) in the high-level group (>2.5) were significantly (P < 0.001) longer than those in the low-level group (≤2.5). The number of CD8 TSL cells was an independent prognostic factor for stage I LUAD. Patients with more CD8 TSL cells had a lower risk of death and disease progression than those with less CD8 TSL cells. CD8 TSL cells were observed in patients with stages I-III LUAD and might serve as prognostic biomarkers for stage I LUAD.

A Metamaterial-like Structure Design Using Non-uniformly Distributed Dielectric and Conducting Strips to Boost the RF Field Distribution in 7 T MRI.

Metamaterial-based designs in ultra-high field (≥7 T) MRI have the promise of increasing the local magnetic resonance imaging (MRI) signal and potentially even the global efficiency of both the radiofrequency (RF) transmit and receive resonators. A recently proposed metamaterial-like structure-comprised of a high-permittivity dielectric material and a set of evenly distributed copper strips-indeed resulted in a local increase in RF transmission. Here, we demonstrate that non-uniform designs of this metamaterial-like structure can be used to boost the ultimate RF field distribution. A non-uniform dielectric distribution can yield longer electric dipoles, thus extending the RF transmit field coverage. A non-uniform distribution of conducting strips enables the tailoring of the local electric field hot spots, where a concave distribution resulted in lower power deposition. Simulations of the brain and calf regions using our new metamaterial-like design, which combines non-uniform distributions of both the dielectric and conducting strips, revealed a 1.4-fold increase in the RF field coverage compared to the uniform distribution, and a 1.5-2-fold increase in the transmit efficiency compared to the standard surface-coil.

Mesoscale model for computational simulation of reaction driven by dielectric breakdown in metal-polymer propellants

The reactivity of heterogeneous energetic materials (HEMs) intimately depends on the underlying microstructural effects. For reactive materials, key factors include the microstructure distribution, morphology, size scale of heterogeneities, reactant mixing, and chemical kinetics of the reactants. We report the development of a mesoscale model for simulating the evolutions of the hotspot field and associated reaction processes when such materials are exposed to external excitations. The model explicitly accounts for microstructure, interdiffusion between the reactant species, advection of the species mixture, and chemical kinetics of the reaction. An Arrhenius relation is used to capture the rate of reactive heat release. The particular material analyzed is a composite of poly(vinylidene fluoride-co-trifluoroethylene) and nanoaluminum [or P(VDF-TrFE)/nAl]. The excitation leading to the initial microstructural temperature increase that kicks off the exothermic reactive processes is the dissipative heating arising from dielectric breakdown under the electric field developed through piezoelectricity and flexoelectricity of P(VDF-TrFE). As such, the model resolves both the breakdown process and the diffusion, advection, and exothermic reaction processes. The evolutions of the temperature and species distribution fields under the combined effects of breakdown and chemistry are used to predict the effects of microstructure, diffusion, and kinetics on several key metrics characterizing the reactive responses of the material. This mesoscale framework admits the quantification of uncertainties in these predicted macroscopic behavior measures due to microstructure heterogeneity fluctuations through the use of multiple, random but statistically equivalent microstructure instantiations. Although the particular hotspot inducing mechanism considered is dielectric breakdown here, the framework can be adapted to analyze reaction initiation and propagation and establish microstructure–reaction behavior relations under other types of hotspot inducing mechanisms, such as thermomechanical inelastic dissipation, frictional heating, and laser or microwave excitation.

Characterization of phenotypic traits associated with anthracnose resistance in selected common bean (Phaseolus vulgaris L.) breeding material

Anthracnose caused by Colletotrichum lindemuthianum is the major common bean disease worldwide causing complete yield loss under favourable disease conditions. This study aimed to determine phenotypic traits associated with anthracnose resistance for future use in breeding programmes. Twenty-two common bean varieties (CBVs) were selected basing on susceptibility to anthracnose, advanced breeding lines, improved variety resembling advanced breeding lines and the farmer variety widely grown in Tanzania. Selected varieties were planted in anthracnose hotspot fields and the same CBVs were planted in a screen house to validate resistance to anthracnose. Anthracnose infection score, leaf length, leaf width, length of fifth internode, length of petiole, plant vigour, canopy height and canopy width were recorded. Data on number of plants emerging; days to flowering; days to maturity; plant stands at harvest; and grain yield were also collected and analysed using R software. Phenotypic traits evaluated differed significantly among genotypes, environment and genotype by environment interaction. Seventy-five percent of phenotypic traits evaluated were positively correlated to anthracnose resistance.Highly-strong correlations to anthracnose were observed on number of days to maturity, plant stands at harvest, plant vigour and grain yield. Leaf length, leaf width, length of fifth internode, length of petiole and number of stands emerging were strongly correlated to anthracnose resistance. Additive main effects and multiplicative interaction analysis (AMMI) revealed highest contribution of environment on anthracnose infection-58.9% and grain yield −84.9% compared to genotype effects on anthracnose infection −32.7% and grain yield-15.7%. Based on these results, four traits – plant vigour, number of days to maturity, number of plant stands at harvest and grain yield – are recommended for selecting anthracnose-resistant varieties. NUA 48, NUA 64 and RWR 2154 were superior varieties, resistant to anthracnose and high yielding, while Sweet Violet and VTT 923-23-10 were most stable varieties across environments. Further on-farm research is suggested to assess their performance and identify traits preferred by farmers.

Screening pearl millet genotypes for resistance to Striga hermonthica and compatibility to Fusarium oxysporum f.sp. strigae

Pearl millet (Pennisetum glaucum [L.] R. Br., 2n = 2x = 14) is a nutritionally rich and climate-resilient food crop cultivated globally. It is a crucial staple crop in Burkina Faso and the dry Sahel region, encompassing Niger, Mali, and Senegal. However, the yield of pearl millet is relatively low in the region (<0.85 tons ha−1) due to Striga hermonthica (Sh) infestation, bird damage, insect pests, diseases, and low-yielding open-pollinated landrace varieties. The study aimed to screen genetically diverse pearl millet accessions for Sh resistance and compatibility to a Striga bio-control agent, Fusarium oxysporum f. sp. Strigae (FOS), to select contrasting and promising parents for resistance breeding and production. One hundred and fifty genotypes were evaluated in Sh hotspot fields in the rain-fed and greenhouse conditions using an alpha lattice design and two replications in Burkina Faso. Significant differences were recorded among the tested pearl millet genotypes for the assessed agro-morphological and Striga resistance. Days to flowering was significantly delayed in the assessed genotypes due to Sh infestation. Applying FOS on pearl millet seed significantly reduced the mean Striga number in Sh-infested conditions. The following genotypes: IP-3098, IP-6112, IP-9242, IP-10579, and IP-11358 were identified as exhibiting Sh resistance and were compatible to FOS. The pearl millet genotypes supported few to none Sh emerged plants with comparatively low values under the Striga number progress curve. The selected genotypes are useful parents to breed for Striga resistance and integrated management in Burkina Faso and related agroecologies.

Regulating thermal diffusion of gold thin films at solid-state interfaces for site-selective decoration of gold nanoparticles on titania nanotubes as an efficient SERS sensing platform

Regulating thermal diffusion and dewetting of Au thin films at the confined ZnO/TiO2 interface favors an optimal distribution of the produced Au nanoparticles for forming localized electromagnetic field hot spots.

Tumor Budding Assessment in Colorectal Carcinoma: Normalization Revisited.

Tumor budding (TB) is a powerful prognostic factor in colorectal cancer (CRC). An internationally standardized method for its assessment (International Tumor Budding Consensus Conference [ITBCC] method) has been adopted by most CRC pathology protocols. This method requires that TB counts are reported by field area (0.785mm 2 ) rather than objective lens and a normalization factor is applied for this purpose. However, the validity of this approach is yet to be tested. We sought to validate the ITBCC method with a particular emphasis on normalization as a tool for standardization. In a cohort of 365 stage I-III CRC, both normalized and non-normalized TB were significantly associated with disease-specific survival and recurrence-free survival ( P <0.0001). Examining both 0.95 and 0.785mm 2 field areas in a subset of patients (n=200), we found that normalization markedly overcorrects TB counts: Counts obtained in a 0.95mm 2 hotspot field were reduced by an average of 17.5% following normalization compared with only 3.8% when counts were performed in an actual 0.785mm 2 field. This resulted in 45 (11.3%) cases being downgraded using ITBCC grading criteria following normalization, compared with only 5 cases (1.3%, P =0.0007) downgraded when a true 0.785mm 2 field was examined. In summary, the prognostic value of TB was retained regardless of whether TB counts in a 0.95mm 2 field were normalized. Normalization resulted in overcorrecting TB counts with consequent downgrading of most borderline cases. This has implications for risk stratification and adjuvant treatment decisions, and suggests the need to re-evaluate the role of normalization in TB assessment.

Measurement of Microvessel Density Using CD105 (Endoglin) as a Marker in Prostatic Adenocarcinoma

Introduction Angiogenesis has been proposed as a promising prognostic marker in a variety of tumours. Microvessel density (MVD) measurement is the most reliable method for the semiquantitative evaluation of angiogenesis. Endoglin (CD105) is a recognised marker of proliferating endothelium and is expressed in intra-tumoral as well as peri-tumoral vessels. It is upregulated in various cancers including prostate cancer, therefore, it is an upcoming prime marker for prognosis, tumour imaging and antiangiogenesis therapy. Aim The study was done to evaluate microvessel density (MVD) by using CD105 (endoglin) as an IHC marker in prostatic adenocarcinoma and to find its relationship with Gleason score and grade groups. Materials and methods This was an observational cross-sectional study under which a total of 31 histopathologically diagnosed cases of prostatic adenocarcinoma on TURP chips were included and were graded according to Gleason score and grades.IHC using endoglin (CD105) was done to detect the highest-density areas of stained vessels (hot spots). The highest value obtained in three hot spot fields was reported as microvessel density (MVD) and its relationship with Gleason score and grade groups was analysed. Results Most common age group was 71-80 years (48.39% cases). Maximum cases (45.16%) had a Gleason score of 9. The maximum mean MVD CD105 score was found in the Gleason grade group 5 (45.32%) while the minimum was in grade group 1 (24%). Comparison of mean MVD CD105 scores in different Gleason grade groups revealed a significant association of MVD CD105 with Gleason grade groups. Conclusion Endoglin measures microvessel density and its expression correlated with Gleason score and grade group. Hence it can be used as a potential prognostic marker in adenocarcinoma prostate.

Adsorbents for the purification and recovery of biocompounds: An updated review

AbstractRecently, the development of techniques to produce detoxified biocompounds has attracted much research interest. This study reviews adsorbents for application in the purification and detoxification of biocompounds, aiming to identify the field's knowledge gaps, trends, updates and hotspots. This review focuses on the description of the types of adsorbents (activated carbon, zeolites, clays, clay minerals and biosorbents) and their activation methods (chemical and physical) for laboratory and industrial adsorption. The adsorbents that stand out are activated carbon and chitosan‐based adsorbents. Moreover, there is a research trend toward using adsorbents to purify bioactive compounds, sugars and amino acids. Finally, adsorbents underscore a growing global research interest in exploring effective treatments for removing various combinations.