Variation Of Concentration Research Articles

Anti-Müllerian hormone: a new approach to fertility assessment in cattle – a review

The anti-Müllerian hormone (AMH) enhances fertility in cattle and hence used as a fertility marker. AMH is produced by granulosa cells of all primordial, primary, secondary follicles, and antral follicles up to 4-5 mm diameter, whereas AMH production decreases once antral stage follicles reach the 4-5 mm stage. There is an individual variation in antral follicle count (AFC) and AMH concentration. One-time determination of AMH concentration will help predict the animals’ reproductive performance at the heifer stage. In turn, it will help to cull those animals with low reproductive potential. There is no significant fluctuation in the AMH concentration during the estrous cycle, and hence it can be determined at any stage of the estrous cycle. This review explores the potential of AMH as a fertility marker and its association with the antral follicle population (AFP) as AMH can be an effective segregative tool to screen low, average or high fertility future performance in cattle.

Aluminum Supplementation Mediates the Changes in Tea Plant Growth and Metabolism in Response to Calcium Stress.

Tea plants are more sensitive to variations in calcium concentration compared to other plants, whereas a moderate aluminum concentration facilitates the growth and development of tea plants. Aluminum and calcium show a competitive interaction with respect to the uptake of elements, consequently exerting physiological effects on plants. To further explore these interactions, in this study, we used the solution culture method to treat tea plants with two calcium concentrations (0.8 mM and 5.6 mM) and three aluminum concentrations (0 mM, 0.4 mM, and 1 mM). We then determined the influence of the combined treatments on root growth and quality compound accumulation in the tissues by a combination of phenotype, gene expression, and metabolite analyses. Moderate aluminum supplementation (0.4 mM) alleviated the inhibition of root growth caused by high calcium stress. High calcium stress significantly inhibited the accumulation of most amino acids (e.g., Glutamic acid, Citulline, and Arginine) and organic acids (e.g., a-ketoglutaric acid) in the roots, stems, and leaves, whereas aluminum deficiency significantly increased most amino acids in the roots and leaves (except Serine, Alanine, and Phenylalanine in the roots and Ser in the leaves), with a more than two-fold increase in Arg and Lysine. High calcium stress also induced the accumulation of secondary metabolites such as epigallocatechin gallate and procyanidin in the roots, whereas aluminum supplementation significantly reduced the contents of flavonol glycosides such as quercetin, rutin, myricitrin, and kaempferitrin, as well as caffeine, regardless of calcium concentration. Aluminum supplementation reversed some of the changes in the contents of leaf metabolites induced by calcium stress (e.g., 4-dihydroquercetin, apigenin C-pentoside, phenethylamine, and caffeine). Overall, calcium stress caused severe growth inhibition and metabolic disorders in tea plants, which could be reversed by aluminum supplementation, particularly in maintaining the root tips and the accumulation of secondary metabolites. These results provide a theoretical basis for improving calcium-aluminum nutrient management to promote tea plant growth and quality.

Change of Lithium concentration in Cedrus atlantica and Pseudotsuga menziesii tissues in the higher air-polluted areas

Heavy metal pollution is today's most critical pollution element, threatening the atmosphere and health. Lithium (Li), a heavy metal, has recently been extensively used in various industrial areas and poses a risk to environmental health, including human health. It is well-known that heavy metals can be much more harmful when taken into the human tissues via inhalation. Therefore, tracking and decreasing the alteration in Li contamination in the airborne is essential. The current study aimed to define whether Pseudotsuga menziesii and Cedrus atlantica are suitable for monitoring and reducing Li pollution in the air. Within the scope of the study, variations in Li concentration depending on organ, direction, and age range in the last 40 years were evaluated in Pseudotsuga menziesii and Cedrus atlantica species growing in Düzce, Türkiye, which is amongst the 5 most contaminated provinces in Europe. As a result, it was determined that Li pollution in the region was of anthropogenic origin and that both species were suitable for monitoring Li pollution but were not suitable for use in reducing it.

Variation in Pb and Zn concentrations in different species of trees and shrubs and their organs depending on traffic density

Global population growth and increasing urban population density together are responsible for many disruptions such as environmental pollution, especially air one. Trace metals are of specific prominence as air pollutants because they are conservative pollutants. They tend to accumulate biologically; some have poisonous or carcinogenic effects, even at small concentrations. Among toxic trace metals, lead (Pb) and zinc (Zn) can be harmful to human health in certain quantities. These trace metals were included in primary pollutant lists of the Agency for Toxic Substances and Disease Registry. Therefore, determining these trace metal concentrations in the air and monitoring the differences is very important for determining the risky districts and the level of risk. Biomonitors are the most important indicators of differences in trace metal concentrations in the atmosphere. The plants chosen as biomonitors intake several of the trace metals from the soil and/or the air into their bodies and determining the level of this accumulation might provide insight into the trace metal pollution of the atmosphere and soil. The present study aims to determine the variations of Pb and Zn concentrations in various landscaping plants growing in different districts of Kastamonu (Türkiye) depending on tree species, organs and traffic density. It was found that unwashed leaves of Acer negundo L. can be suggested as a good biomonitor for the presence of both analysed trace metals. Keywords: biomonitor; air pollution; trace metal; lead; zinc; traffic

Volatile constituents of Nardostachys jatamansi DC. rhizomes: from Uttarakhand Himalaya (India)

The rhizomes of Nardostachys jatamansi DC. were collected from two alpine Himalayan locations of Uttarakhand (India). The essential oils were obtained by hydro-distillation and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) in order to determine the variation of concentration in their constituents. A total of 22 compounds were identified in both the oils, accounting 96.4198.22%. The major constituents of N. jatamansi oils were characterised as patchoulol (46.054.11%) and calarene (9.1015.6%). Due to the higher relative area quantum of patchoulol in N. jatamansi populations growing in Uttarakhand, there is need to develop propagation protocol for mass multiplication and in-situ and ex-situ conservation.

Permanent magnet systems to study the interaction between magnetic nanoparticles and cells in microslide channels

We optimized designs of permanent magnet systems to study the effect of magnetic nanoparticles on cell cultures in microslide channels. This produced two designs, one of which is based on a large cylindrical magnet that applies a uniform force density of 6MN/m3 on soft magnetic iron-oxide spherical nanoparticles at a field strength of over 300mT. We achieved a force uniformity of better than 14% over the channel area, leading to a concentration variation that was below our measurement resolution. The second design was aimed at maximizing the force by using a Halbach array. We indeed increased the force by more than one order of magnitude at force density values over 400MN/m3, but at the cost of uniformity. However, the latter system can be used to trap magnetic nanoparticles efficiently and to create concentration gradients. We demonstrated both designs by analyzing the effect of magnetic forces on the cell viability of human hepatoma HepG2 cells in the presence of bare Fe2O3 and cross-linked dextran iron-oxide cluster-type particles (MicroMod). Python scripts for magnetic force calculations and particle trajectory modeling as well as source files for 3D prints have been made available so these designs can be easily adapted and optimized for other geometries.

Utilization of cassava peel waste (Manihot esculenta L.) with concentration variations of α-amylase and glucoamylase enzymes for liquid sugar

Utilization of cassava peel waste (Manihot esculenta L.) with concentration variations of α-amylase and glucoamylase enzymes for liquid sugar

Investigation on the structure-optimized magnetic properties of hydrothermally synthesized SrBi2−X(CF)XNb2O9 multiferroic nanocomposites

Hydrothermally synthesized nano multiferroic SrBi2-X(CF)XNb2O9 (SBN-CF), (CF = CoFe2O4 & X = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) composite’s structure correlated magnetic attributes in view of reaction, exchange, and transport of ions have been comprehended from the perspective of electronic sector applications. The produced materials’ phase genesis, morphology, chemical composition, and magnetic characteristics were studied by XRD/Rietveld analysis, FEGSEM/EDS, FTIR, and VSM respectively. The Rietveld analysis of XRD data confirmed a single-phase orthorhombic structure of SBN. Further ferroelectric and cubic spinel structures of the ferrite phase have been noticed from the introduction of CF into the SBN host matrix. The crystallite size as computed (∼23–41 nm) from Debye Scherer’s formula was found to increase with dopant concentration. The imbibed morphological changes necessitated octahedral-shaped grains. The stoichiometric proportion with pronounced absorption bands is evident in EDS and FTIR studies. The impact of CF on SBN was unraveled at room temperature from the VSM study. The saturation magnetization was increased from 0.00 to 3.96 emu g−1, and the obtained coercivity values enhanced from 0.50 to 1400 Oe, due to the random fluctuations of the energy due to domain wall movements, interacting with the defective structure of the SBN material. The stress-induced distortion due to the variation in concentration of CF in SBN was configured from Y-K angles and increased from 33.55° to 61.49°. The high coercivity with a squareness value of less than 0.5 enunciates the genesis of a new class of materials for use in permanent magnet applications and memory devices.

Pilot SERS Monitoring Study of Two Natural Hypersaline Lake Waters from a Balneary Resort during Winter-Months Period.

Water samples from two naturally hypersaline lakes, renowned for their balneotherapeutic properties, were investigated through a pilot SERS monitoring program. Nanotechnology-based techniques were employed to periodically measure the ultra-sensitive SERS molecular characteristics of the raw water-bearing microbial community and the inorganic content. Employing the Pearson correlation coefficient revealed a robust linear relationship between electrical conductivity and pH and Raman and SERS spectral data of water samples, highlighting the interplay complexity of Raman/SERS signals and physicochemical parameters within each lake. The SERS data obtained from raw waters with AgNPs exhibited a dominant, reproducible SERS feature resembling adsorbed β-carotene at submicromole concentration, which could be related to the cyanobacteria-AgNPs interface and supported by TEM analyses. Notably, spurious SERS sampling cases showed molecular traces attributed to additional metabolites, suggesting multiplexed SERS signatures. The conducted PCA demonstrated observable differences in the β-carotene SERS band intensities between the two lakes, signifying potential variations in picoplankton abundance and composition or environmental influences. Moreover, the study examined variations in the SERS intensity ratio I245/I1512, related to the balance between inorganic (Cl--induced AgNPs aggregation) and organic (cyanobacteria population) balance, in correlation with the electrical conductivity. These findings signify the potential of SERS data for monitoring variations in microorganism concentration, clearly dependent on ion concentration and nutrient dynamics in raw, hypersaline water bodies.

Deep Learning-Based Simulation of Surface Suspended Sediment Concentration in the Yangtze Estuary during Typhoon In-Fa

Effectively simulating the variation in suspended sediment concentration (SSC) in estuaries during typhoons is significant for the water quality and ecological conditions of estuarine shoal wetlands and their adjacent coastal waters. During typhoons, SSC undergoes large variations due to the significant changes in meteorological and hydrological factors such as waves, wind speed, and precipitation, which increases the difficulty in simulating SSC. Therefore, in this study, we use an optimized Principal Component Analysis Long Short-Term Memory (PCA-LSTM) framework with an attention mechanism to simulate the SSC in the Yangtze Estuary during Typhoon In-Fa. First, we integrate data from different sources into a multi-source dataset. Second, we use the PCA to reduce the dimensionality of the multi-source data and eliminate redundant variables in the feature data. Third, we introduce an attention mechanism to optimize the long and short-term memory (LSTM) model. Finally, we use the differential evolution (DE) algorithm for hyperparameter selection and merge the feature data with the SSC data as the input of the optimized LSTM network to simulate SSC. The results showed that SSC’s fitting coefficients (R2) at four hydrological stations improved by 7.5%, 6.1%, 7.4%, and 7.8%, respectively, using the attention-based PCA-LSTM compared to the PCA-LSTM. Moreover, compared to the traditional LSTM model, the R2 was improved by 33.8%, 30.5%, 32.0%, and 28.6%, respectively, using the attention-based PCA-LSTM framework. The study indicates that the selection of input variables can affect the model results. Introducing an attention mechanism can effectively optimize the PCA-LSTM framework and improve the simulation accuracy, which helps simulate the non-linear process of SSC variation occurring during Typhoon In-Fa.

Impacts of compound extreme weather events on summer ozone in the Beijing-Tianjin-Hebei region

The Beijing-Tianjin-Hebei (BTH) region faces severe summer ozone (O3) pollution. In this study, we conducted a comprehensive analysis of O3 concentration variations during compound extreme (CE) weather events that occur simultaneously with atmospheric stagnation and heat wave during the summer period from 2015 to 2021. Our results showed that during CE events, the rate of O3 exceedance was nearly three times higher compared to non-CE days. O3 concentrations remained relatively stable during CE events lasting five days or less in regions other than Beijing, but when CE events extended beyond five days, both O3 concentration and the exceedance rate increased rapidly. Under CE conditions, daily O3 pollution persisted for a longer duration with 70.0% of daily O3 peaks surpassing 200 μg m−3, especially between 7 a.m. and 12 p.m., the time when CE events had a significant impact on O3 concentration characterized by a rapid rise in O3 concentration. The movement of the western Pacific subtropical high towards the east and its northward shift may contribute to the occurrence of favorable conditions for CE events in the BTH region, but meteorologically these results can be attributed to anticyclonic and high-pressure system anomalies during CE events in the BTH region, which are characterized by low total cloud cover, high temperature, low relative humidity, and high radiation. Positive anomalies in vertical velocity further contribute to favorable conditions for photochemical O3 formation, accumulation, and persistent O3 exceedances.

Nanoparticles encapsulated carbon nanotubes dispersed lubricants for enhanced tribology through particle‐phase variation

AbstractNanostructures as an inert additive to the lubricant act as a tiny friction reduction element by providing asperity filling, polishing, and film formation mechanism at the nanoscale dimension under the boundary layer regime. Here, we explore the synthesis and tribology application of iron‐carbon‐based nanoparticles encapsulated multiwall carbon nanotubes (Fe‐C‐CNTs). Three Fe‐C nanoparticles phase that is, Fe3C‐CNTs, Fe3C‐Fe‐CNTs, and Fe‐CNTs are synthesised. In particular, the emphasis here is on the effect of nanoparticle phase variation on the tribology property. The tribology property of the prepared nanomaterials is studied by dispersing it in commercially used Servo gearbox oil. The coefficient of friction and wear is found reduced in all dispersions compared to the base gearbox oil confirming the manifestation of nanoscale mechanisms at the tribo‐interface. It is revealed that the phase variation shows more impact on the alteration of friction coefficient compared to the dispersion concentration variation analysed using ANOVA two‐way technique. Further, the diameter and composition analysis of the wear scar is used to comprehend the underlying mechanism of the encapsulated particle phase variation. The findings suggest that the Fe‐CNTs dispersions are efficient in reducing friction to a larger extent but also promote the interface oxidation leading to enhanced wear and roughness whereas, Fe3C‐CNTs and Fe3C‐Fe‐CNTs are chemically stable providing smooth sliding and less wear.

Antibacterial and antifungal activity of curcumin and methylene blue associated with laser on bacterial and fungal strains

Objective: To analyze the effect of methylene blue and 10% curcumin in fungi and bacteria through an in vitro study using photodynamic therapy (PDT). Methods: Curcumin and methylene blue were photosensitized by a Photon Lase III laser applied for 90 s in a dark environment within a laminar flow chamber. Enterococcus faecalis and Candida albicans strains were cultured and standardized. Then, a minimum inhibitory concentration (MIC) assay was conducted for these photosensitizers, with concentration variations and incubation to evaluate their antimicrobial activity. Results: With PDT, Curcumin had significant antibacterial activity against E. faecalis (MIC = 250 µg/mL). In contrast, methylene blue had antibacterial activity against E. faecalis (MIC < 12.5 µg/mL with PDT) and antifungal activity against C. albicans (MIC <12.5 µg/mL with or without PDT). Both agents showed greater efficacy in the presence of the laser. The results suggest that curcumin and methylene blue associated with laser may effectively treat microbial infections. Conclusion: Further research is needed to evaluate the efficacy and safety of using these agents in animal and human models and their effectiveness against different bacterial and fungal strains.

Exhaust Emission Assessment of Haulage Trucks at Onne Port, Nigeria

Haulage trucks are among the primary causes of air pollution in urban areas. The effect of air pollution caused by transportation, especially freight transportation, on public health is a major concern globally. In this study, emissions of haulage trucks operating at Onne Port, Rivers State in Nigeria were assessed to understand their contribution to local air pollution and environmental impact. Real-time measurements of air pollutants were taken using a portable Testo 350 Analyzer and a portable IGRESS Intelligent Detector from seventy (70) haulage trucks at Onne Port grouped according to production years, region of origin, and truck length, and the data obtained were compared with the World Health Organization (WHO) air quality standards. The results revealed that the trucks’ emissions exceeded WHO limits for six criteria pollutants, including NO2, SO2, CO, PM1, PM2.5, and PM10, which are associated with adverse health effects such as respiratory and cardiovascular diseases. Other notable findings included higher concentrations of NO2 at 35.48 ppm and PM2.5 at 300.73 µg/m3 from trucks produced between 2011 and 2021, while older trucks exhibited increased emissions of SO2 at 31.16 ppm, CO at 775.87 ppm, PM1 at 216.75 µg/m3, and PM10 at 341.75 µg/m3. There were no significant variations in pollutant emission concentrations observed within the four categories across different production years. Trucks manufactured in Asia consistently emitted lower pollutant concentrations compared with those from other regions, suggesting the influence of varying emission standards. Interestingly, truck length did not significantly impact emission levels. These findings underscore the urgency of addressing the air quality issues associated with haulage trucks in the region, highlighting the need for stringent emissions control measures.

Towards chitosan-amorphous calcium phosphate nanocomposite: Co-precipitation induced by spray drying

This article reports the successful one-step synthesis of two micron-sized composite powders consisting of chitosan and amorphous calcium phosphate. These composite materials are prepared by spray drying of a solution containing chitosan and calcium phosphate precursors. The co-precipitation of chitosan and calcium phosphate precursors during the process induces a highly homogeneous distribution of the phases. The mineral phase identified as spherical nanoparticles dispersed in chitosan showed no chemical bonding with the polymer. As demonstrated by electron microscopy, small angle X-ray scattering and spectroscopies, variation in chitosan concentrations significantly influences the size and spatial distribution of the mineral phase. These results present a promising approach for the preparation of chitosan/amorphous calcium phosphate composite powders with controlled and tunable properties with potential applications in the field of biomaterial engineering such as bone substitutes.

Resource Disposal and Products of Fly Ash from Domestic Waste Incineration in Zhejiang Province, China: Migration and Change of Hazardous Heavy Metals

At present, domestic waste incineration fly ash is classified as hazardous waste. The technical hurdle of fly ash detoxification and resource usage must be overcome in order to effectively utilize fly ash resources. In this study, we investigate the migration and transformation of heavy metal contaminants in the course of utilizing domestic waste incineration fly ash resources through the technology pathway of low-temperature pyrolysis, cyclic rinsing, and evaporation crystallization. Firstly, a comparative analysis was conducted on the fly ash (FA), pyrolysis ash (PA), and water-washing ash (WA) resulting from domestic waste incineration, revealing 24 types of metals, 3 types of non-metals, and 8 types of oxides. We observed the variations in heavy metal concentrations as well as the acidity and alkalinity in three types of ash resulting from the regenerated salt (RS) and incineration processes. Moreover, we analyzed the changes in heavy metal levels and acidity and alkalinity of treated saline water (TSW) and industrial brine (IB), which originate from the fly ash treatment process. The study’s results have confirmed that the heavy metal content in RS was below the detection limit following resource treatment. In addition, the regenerated salt product is determined to be a CaO-SiO2-Al2O3-Fe2O3 system, which enables the utilization of fly ash as a valuable resource. Notably, there were significant changes observed in heavy metal content in TSW and IB. Continued attention needs to be paid to the potential risk of environmental contamination from heavy metals and dioxins in FA infiltration. This research will prove beneficial in assessing resource utilization potential of products subjected to environmentally sound incineration fly ash treatment.

Occurrence of Major Perfluorinated Alkylate Substances in Human Blood and Target Organs.

Human exposure to perfluorinated alkylate substances (PFASs) is usually assessed from the concentrations in serum or plasma, assuming one-compartment toxicokinetics. To characterize body distributions of major PFASs, we obtained and extracted tissue samples from 19 forensic autopsies of healthy adult subjects who had died suddenly and were not known to have elevated levels of PFAS exposure. As target organs of toxicological importance, we selected the liver, kidneys, lungs, spleen, and brain, as well as whole blood. Samples weighing about 0.1 g were analyzed by liquid chromatography coupled to triple mass spectrometers. Minor variations in PFAS concentrations were found between the kidney cortex and medulla and between lung lobes. Organ concentrations of perfluorooctanoic sulfonate (PFOS) and perfluorononanoate (PFNA) correlated well with blood concentrations, while perfluorooctanoate (PFOA) and perfluorohexanoic sulfonate (PFHxS) showed more variable associations. Likewise, the liver concentrations correlated well with those of other organs. Calculations of relative distributions were carried out to assess the interdependence of organ retentions. Equilibrium model predictions largely explained the observed PFAS distributions, except for the brain. Although the samples were small and affected by a possible lack of homogeneity, these findings support the use of blood-PFAS concentrations as a measure of PFAS exposure, with the liver possibly acting as the main organ of retention.

Design and performance evaluation of Alkaline-Surfactant-Polymer slug of a natural surfactant of fenugreek in saline media for Foaming/Emulsification applications

The increasing demands of oil energy has created burden on conventional oil recovery methods because of which use of synthetic chemicals is increasing and creating significant health and environmental issues. Therefore, this study reports the synthesis of alkali-surfactant-polymer (ASP) slug with the use a natural surfactant and natural polymer as an alternate for foaming in saline environment of chemical-EOR applications. The natural surfactant (used at CMC level) derived from fenugreek seeds and guar gum (4000 ppm) was used as natural polymer, while the concentration of NaHCO3 (alkali) was tuned to curtail the impact of salt-ions on foam-ability of ASP slug for practical applications. It was observed that a stable air foam developed in saline medium due to the synergistic interaction between alkali-polymer. The desired ASP slug (nomenclature: 0.5ASP1) of 0.5 wt% alkali, 0.2 wt% surfactant (CMC), and 4000 ppm guar gum was developed after significant tuning in alkali concentration as per the variation in NaCl concentration (1–8 wt%). The desired slug 0.5ASP1 showed significant foaming potential till NaCl concentration of 2 wt% as demonstrated by superior foam height of 139.8 mm at span of 60 s which was only 113.4 mm for ASP slug (at salinity 2 wt%). The presence of alkali, capable of generating in-situ surfactant, and inclusion of additional natural surfactant in ASP formulation (0.5ASP1) resulted into minimum SFT of 38 mN/m and contact angle of 54°. This indicates a favorable impact of ASP slug on wettability alteration of reservoir rock and making them more water-wet. Microscopic investigations were also conducted to visualize packing and coverage of foam bubbles stabilized by 0.5ASP1 and ASP slugs. 0.5ASP1 slug sustained bubbles for longer duration than ASP slug. The results concluded that inclusion of natural derivative in form of surfactant and polymer along with inexpensive alkali makes ASP slug a green alternative for practical applications such as oil recovery, crude emulsification, CO2 foams, and IFT reduction.

Assessing torrentiality in catchments of the tropical Andes: A morphometric approach

Torrential flows represent one of the most catastrophic natural hazards in the Andes, and Colombia is not an exception. We computed and analyzed ten morphometric indexes, classified by the catchment geometry and relief characteristics, for 149 torrential catchments across Colombian Andes three branches (Western, Central, and Eastern cordilleras). We divided the study area into six tectonic-stratigraphic regions, and employed statistical tests such as the Shapiro-Wilk and ANOVA One-Way Permutation tests to assess index distributions within each region. The ANOVA One-Way Permutation test results revealed significant differences in the distributions of form factor (p-value 0.048), mean gradient (p-value 0.009), relief ratio (p-value 0.003), Melton ratio (p-value 0.006), and hypsometric integral (p-value 0.000) indices among regions. Likewise, the pairwise comparison tests identified that the following regions are different between them for Melton ratio: Central Cordillera and Plateau Antioqueño (p-value 0.032), Garzón Massif and Plateau Antioqueño (p-value 0.015), Garzón Massif and Santander Massif (p-value 0.05), and Plateau Antioqueño and Western Cordillera (p-value 0.032); for relief ratio: Central Cordillera and Plateau Antioqueño (p-value 0.0219), Estern Cordillera and Plateau Antioqueño (p-value 0.0425), Garzón Massif and Plateau Antioqueño (p-value 0.0058), Plateau Antioqueño and Western Cordillera (p-value 0.053); for hypsometric integral: Central Cordillera and Western Cordillera (p-value 0.0004), Eastern Cordillera and Western Cordillera (p-value 0.0004), Garzón Massif and Western Cordillera (p-value 0.0004), Plateau Antioqueño and Western Cordillera (p-value 0.0161), and Santander Massif and Western Cordillera (p-value 0.002). Based on the findings we computed confidence intervals for the population median of the studied morphometric parameters according to the region employing a non-parametric bootstrapping method. The statistical analysis highlights the importance of the geological and geomorphological features in the morphometric indices analysis as part of the torrential flow susceptibility assessment.Applying our findings, we tested proposed thresholds in a case study of the Santander Massif (Eastern Cordillera of Colombia), focusing on the 2020 Piedecuesta Flow. In the study case, we demonstrated the relevance of identifying the feeder catchments where the morphometric indices would be calculated from, especially in areas where significant hydrologic changes occur. Volumetric concentration variations along the Piedecuesta Flow path highlight the need to prioritize the recognition of feeder catchments as an imperative part of the susceptibility assessment. Our approach enriches the knowledge base for identifying torrential-prone basins and has important implications for natural hazard management, aiming at mitigating the impact of torrential flows in the Andes.

Phase Transitions of Naphthalene-2,3-carbonitride Steered by Solvent Effects and Metal Ion Concentration Variation.

The delicate regulation of structural phase transition can provide advanced approaches for fabricating desired and well-organized nanoarchitectures on surfaces. Introduction of metal ions into pure organic systems can facilitate the phase transition from hydrogen-bonded structures to metal-organic structures by coordinating with organic molecules. However, it remains a challenge to attain a phase transition dominated by variable metal coordination configurations through adjustment of the metal ion concentration. Herein, we report the phase transitions of naphthalene-2,3-carbonitride (2,3-DCN) molecules on highly oriented pyrolytic graphite (HOPG) under varying solvents and Cu2+ ion concentrations. By integrating data from scanning tunneling microscopy imaging and density functional theory calculations, it is demonstrated that phase transitions of 2,3-DCN occur through forming diverse coordination configurations where Cu2+ ions can coordinate with 2,3-DCN and 1-nonanoic acid or Cl- ions to form different ligand components with a coordination number of 4 when varying the molar ratios of 2,3-DCN to Cu2+ ion in the 1-nonanoic acid solvent. However, in the case of 1-heptanoic acid as a solvent, the self-assembly structure of 2,3-DCN only changes via the alteration of hydrogen bonding sites and Cu2+ ions do not coordinate with 2,3-DCN molecules. These findings provide valuable insights into the coordination behavior of metal ions in different solvents.