Current Range Research Articles

On the path to extinction: Helix godetiana Kobelt, 1878, the only threatened Helix species in Greece

Land snails and the Aegean Archipelago offer an intriguing combination for studying biodiversity, biogeography and ecology. A region with high environmental and temporal heterogeneity and a tri-continental biotic influence and a group of organisms with low active dispersal abilities, high endemism, as well as the particularity to leave shells as traces of past presence, set an ideal stage for testing biodiversity patterns and exploring multisource threats, especially in the era of the ongoing biodiversity crisis. In this study, we examine Helix godetiana, a large-sized, threatened and endemic land snail of the central and south Aegean Islands. The species has been extirpated from 22 of the 32 islands where it was historically present. We identify potential drivers of its extinction, as Helix godetiana faces several threats across its current range, including competitive exclusion by Cornu aspersum, a species with continuing expansion in the Aegean and climate change disrupting its unusual breeding cycle, which occurs in late spring. Our findings shed light on potentially major, yet previously unexplored, threats on endemic molluscs of the Aegean Islands, a European biodiversity hotspot.

The temperate forest phyllosphere and rhizosphere microbiome: a case study of sugar maple

The interactions between sugar maple (Acer saccharum, Marshall) and its microbial communities are important for tree fitness, growth, and establishment. Despite recent progress in our understanding of the rhizosphere and phyllosphere microbial communities of sugar maple, many outstanding knowledge gaps remain. This review delves into the relationships between sugar maple and its microbes, as climate change alters plant species distributions. It highlights the multifaceted roles of key microbes, such as arbuscular mycorrhizal (AM) fungi and pathogens, in affecting the distribution and establishment of sugar maple in novel habitats. Furthermore, this review examines how microbial communities in different compartments contribute to tree fitness. Finally, it explores how microbial dispersal and altered species interactions under changing environmental conditions can affect sugar maple's ability to migrate beyond its current range, emphasizing the different scenarios associated with such shifts. In the rhizosphere, AM fungi are known for their roles in nutrient acquisition and improving stress tolerance. Yet, key questions remain about how these fungi interact with other microbes, how soil chemistry and climate change alter these interactions, and how the presence of beneficial microbes influences sugar maple's establishment. Additionally, the role of dark septate endophytes (DSE) in sugar maple's fitness remains underexplored, emphasizing the need for more research on their diversity and functions. In the phyllosphere, microbial communities are subject to shifts due to rising global change, with potential impacts on sugar maple's fitness. These changes may influence the tree's resistance to pathogens, tolerance to environmental stress, and overall health. Yet, our understanding of these interactions relies mostly on short-read sequencing methods targeting marker genes (e.g., 16S, ITS, 18S), which often fail to identify microbes at the species level. Limitations in molecular techniques and poor microbial reference databases hinder our ability to fully characterize tree-associated microbial diversity and functions. Future research should thus prioritize advanced molecular tools such as shotgun, hybrid, or long-read sequencing. Controlled experiments are also needed to establish causal links between sugar maple fitness and microbial communities, and to study whether microbial communities change throughout the tree's lifespan.

A new pheretimoid earthworm of the genus Metaphire Sims & Easton, 1972 (Oligochaeta, Megascolecidae) from northeastern China with data from the mitochondrial genome

A new pheretimoid earthworm species, Metaphire liaoningensissp. nov., was investigated in northeastern China. The taxonomy of M. liaoningensissp. nov. using morphological characters and molecular data is reported, as well as its current geographical range in northeastern China. The new species, belonging to the M. houlleti species group, is characterized by having three pairs of spermathecal pores in 6/7/8/9, round and small pre-clitellar genital markings medio-ventral to the spermathecal pore opening, the first dorsal pore in 12/13, and the spermathecae ampulla large, nearly elliptical with a surface wrinkled and a duct long and stout. The molecular phylogenetic position of M. liaoningensissp. nov. within the M. houlleti species group is performed by COI and mitogenomic data, respectively. The COIK2P genetic distance between the new species and the other species within the M. houlleti species group was at least 16%. This is the second updated report of a new pheretimoid species in northeastern China since the last decade.

Study on the Hydrogen Evolution Reaction of Reinforced Concrete during Electrochemical Repair under the Influence of BIEM.

Based on the bidirectional electromigration (BIEM) technique, a corrosion inhibitor solution was prepared by mixing 1 mol/L triethylene tetramine with deionized water. The effects of current density, charging time, and corrosion inhibitor on critical current density and hydrogen content of rebar were investigated. Subsequently, the hydrogen embrittlement risk of rebar was further characterized by mechanical property tests. Finally, the bearing capacity and crack distribution characteristics of the components during electrochemical repair were revealed based on the microstructure of the steel fracture. Studies have shown that the corrosion inhibitor in the BIEM electrolyte reduces the polarization potential, increases the critical current density, and finally inhibits the hydrogen evolution rate. The hydrogen evolution reaction increases with the increase of current density and energizing time. The critical hydrogen evolution current density of concrete specimens measured ranges from 0.796 to 0.833 A/m2. In addition, the current density range of 1-7 A/m2 has no effect on the yield strength, yield platform, and ultimate strength of steel. With the increase of 1 μg/g hydrogen content, the fracture energy ratio of steel bars decreases by 12.18%, and the sensitivity coefficient of hydrogen brittleness increases by 9.92%.

Indented metallic bipolar plates for vanadium redox flow batteries

The standard industrial vanadium redox flow battery (VRFB) stack is made of thick graphite bipolar plates to support the flow field required for optimal circulation of electrolyte. These thick plates suffer from electrolyte seepage, poor mechanical properties, and high machining and processing costs. In the present study, we report on the use of metallic bipolar plates for the construction of the VRFB cell. We show, through comprehensive electrochemical and hydrodynamic investigations, that Hastelloy C276, a corrosion-resistant high Nickel alloy, is a suitable bipolar plate material in VRFB cells. We show further that surface texture modification, in the form of a mix of concave and convex spherical indentations on the metallic bipolar plate, can have beneficial effects on cell performance. Comparative experiments on medium-size cells of a nominal area of 440 cm2 operating in the current density range of 75–125 mA/cm2 show that discharge energy gains of 25% or higher can be obtained together with a 10–15% reduction in pressure drop in comparison with similar cells with flat bipolar plates. It is posited that the concave indentations spread over the entire area ensure uniform electrolyte circulation while regions of low and high electrode compression create flow channeling possibilities that lead to reduced pressure drop.

Modified Harmonic Current Control and Load Range Extension Method for Single-Stage Isolated DCM Boost AC–DC Converter

Modified Harmonic Current Control and Load Range Extension Method for Single-Stage Isolated DCM Boost AC–DC Converter

Geostatistical Model Development and Assessment of Tidal Stream Energy Resources: A Case Study of Indus Delta, Pakistan

In this paper, an approach is applied by using the Geographical Information System for the development of geostatistical models to assess available tidal stream energy resources of the Indus Delta Creek system. The mean spring tidal current of twelve different locations in the Indus Delta Creek system (Pakistan) is utilized to develop geostatistical models for the prediction of tidal currents at different locations where no data was available. Models are validated and an investigation of prediction error is carried out to select the best model. For the prediction of tidal stream data, various models are collated namely (i) Circular (ii) K-Bessel (iii) Stable, and (iv) Exponential. These models show the range of mean spring ebb current between 1.9 m/s and 2.12 m/s and the range of mean spring flood current between 1.4 m/s and 1.65 m/s. The stable model for mean spring flood current and circular model for mean spring ebb current agreed with the observed ones. Furthermore, the tidal kinetic power density model and bathymetry model are also developed for the selection of potential sites within the study area. Based on results achieved from geostatistical and bathymetry models; deployment of the suitable turbine at the study area is proposed and generation of 2754.7 MW electric power is estimated.

Characterization of Rice Husk for Graphene Extraction and Metallization

Rice husk, an underutilized agricultural waste product, serves as a potential precursor for graphene synthesis. This study focuses on synthesizing and characterizing graphene through the chemical exfoliation method, employing advanced analytical techniques to explore its potential applications in metallization. Graphene was produced by chemically activating rice husk ash (RHA) with potassium hydroxide (KOH) at 800 ºC. The extracted graphene underwent analysis using various techniques. X-ray Diffraction (XRD) confirmed the material's crystalline nature and graphitic structure. Fourier-Transform Infrared Spectroscopy (FTIR) identified typical functional groups present in the synthesized graphene. Raman Spectroscopy revealed significant defects and confirmed that the graphene consists of single or few-layer thin sheets. Transmission Electron Microscopy (TEM) showed the presence of thin graphene sheets and nanoparticles with sizes ranging from 1.47 nm to 5.80 nm. Ultraviolet-Visible Spectroscopy (UV-Vis) confirmed electronic structure and optical properties, essential for metallization. X-ray Fluorescence (XRF) confirmed the purity of the graphene, while Brunauer-Emmett-Teller (BET) analysis revealed a high specific surface area, making the material suitable for surface-based applications. Electrical conductivity tests demonstrated good conductivity in the lower to moderate current range. The study underscores the potential of rice husk-derived graphene for metallization, offering a cost-effective and eco-friendly synthesis method for industrial and commercial applications.

High Performance GaSb-Based DBR Laser with On-Chip Integrated Power Amplifier via Gain-Match Design

We reported on a single-longitudinal-mode operated distributed Bragg reflector laser diode emitting at 1950 nm with an on-chip integrated power amplifier. Second-order Chromium–Bragg gratings are carefully designed and fabricated at the end of the ridge waveguide. Achieving a stable single-mode operation with a large injecting current range of 800 mA from 15 °C to 40 °C. The maximum side-mode suppression ratio (SMSR) is up to 42 dB. To increase the output power, an on-chip integrated master oscillator power amplifier (MOPA) is also introduced. MOPA-DBR lasers with different matching configurations between the gain peak and Bragg wavelength are fabricated, resulting in various amplification consequences. The best device is realized with 40 nm red-shifted between Bragg wavelength and photoluminescence (PL) peak. A power amplification of 5.6 times is achieved with the maximum output power of 45 mW. Thus, we put up the feasibility and key design parameters of on-chip integrated power amplification DBR lasers towards mid-infrared.

A Degradation Model of Electrical Contact Performance for Copper Alloy Contacts with Tin Coatings Under Power Current-Carrying Fretting Conditions

The fretting degradation of coating materials is complicated when the Joule heating effect of the load current is non-negligible. In this work, the fretting degradation behavior of tin-coated copper alloy contacts was examined across the current range from 5 A to 30 A and the fretting amplitude range from 200 μm to 400 μm. The uniform degradation process and associated mechanisms, including the wear-dominated stage, softening-dominated stage, and oxidation-dominated stage were recognized and interpreted explicitly. An innovative fusion model for the degradation of electrical contact performance, data-driven and based on physics mechanism, was proposed. The contact voltage was selected as the characterization variable and pre-processed by the threshold-crossing filter method and the Levenberg–Marquardt algorithm. The optimal degradation model, considering the coupled effects of current and fretting amplitude, was presented with the use of the support vector regression method. Finally, the prediction accuracy of the model was validated by experiment results.

Influence of Y2O3 on microstructure and properties of 800 MPa high-strength steel weld metal

This study investigated the effect of Y2O3 on the microstructure and properties of 800 MPa high-strength steel weld metal using optical microscopy, scanning electron microscopy, and mechanical testing. The groove faces and contacting surfaces of the base material, hot-rolled Q235 carbon steel, were buttered using high-strength steel metal-powder cored wires. The main welding parameters employed in the experiments included a voltage range of 29–31 V, a current range of 220–240 A, a welding speed of 250–260 mm/min, and shielding gases consisting of 80% Ar and 20% CO2. The results indicated that the addition of 1% Y2O3 effectively refined the grain structure, resulting in a acicular ferrite content of 80%. Furthermore, Y2O3 promoted the refinement and spheroidisation of inclusions, leading to an improvement in the toughness of the weld metal. Y2O3 also enhanced the lath microstructure and inhibited the formation of martensite and bainite. The mode of crack formation shifted from boundary cracking to the surface shear stress-induced decohesion of inclusions due to the presence of Y2O3. The weld metal containing 1% Y2O3 exhibited excellent mechanical properties, with a tensile strength of 769 MPa and an impact absorbed energy of 70 J.

Bifunctional Design of Ferroelectric-Order and Band-Engineering in Cu:KTN Crystal for Extended Self-Powered Photoelectric Response.

Photoelectric conversion in ferroelectric crystals can support many important applications in modern on-chip technology, but suffering from two problems, low responsive current and narrow responsive range. Especially, wide-gap ferroelectric oxides are only active at short-wavelength ultraviolet region with weak photocurrent at nanoampere levels. Here, a bifunctional design strategy of ferroelectric-order and electronic-band to improve the photocurrent and extend the responsive range simultaneously, is proposed. In a Cu-doped KTa1- xNbxO3 (KTN) perovskite crystal, a conductive channel is constructed by "head-to-head" ferroelectric domains, associated with the emergence of micrometer-scale supercells. In addition, the introduction of Cu+ ion can induce defect levels, thus extending the responsive range beyond the inherent absorption of pure KTN. Through rational device optimization, a record self-powered responsivity of 5.23 mA W-1 is realized in Cu:KTN photodetector, which is two orders of magnitude higher than undoped KTN crystal. The temperature-dependent light diffraction and photocurrent show that the ferroelectric-order is dominated in this photoresponse behavior. Moreover, Cu:KTN detector is active in the broadband range from 390 to 1030 nm, covering ultraviolet, visible, and near-infrared regions. This work provides an effective method for the design of next-generation self-powered photodetectors with ultrahigh responsivity and ultrawide responsive range.

Simulation of Suitable Distribution Areas of Magnolia officinalis in China Based on the MaxEnt Model and Analysis of Key Environmental Variables

Magnolia officinalis Rehder & E.H. Wilson is a deciduous tree in the Magnoliaceae family with extensive medicinal uses in China and Japan, being used to treat symptoms such as indigestion, insomnia, and anxiety. In this study, we used the MaxEnt model to (1) simulate the suitable spatial distribution areas of M. officinalis in China in the current and future periods (2050s and 2090s) and, (2) identify the key environmental variables affecting its spatial distributions by comparing the changes in the center of mass of the suitable areas under the current and projected future climate. The research results show that the current distribution range of M. officinalis is mainly between east longitude 102.2° to 122.2° and north latitude 23.7° to 33.9°, and it is located in the subtropical region of China. In the future, only the high-suitability area under scenario SSP1-2.6 and the low-suitability area under scenario SSP5-8.5 decreased in the 2050s, while the area increased under all other conditions. In the 2050s, the high- and medium-suitability areas under the SSP5-8.5 scenario increased the most, by 54.76% and 20.90%, respectively. Most of the key bio-climatic variables affecting the spatial distributions of M. officinalis are related to temperature and precipitation, and soil, terrain, chemical, and human variables that are also key environmental variables affecting the spatial distributions of M. officinalis. Currently, the suitable spatial distribution centroid of M. officinalis is at (111.71° E, 28.52° N), but it will change in the future climate; although, it will still be located in Hunan Province. This study predicts the spatial distribution areas that are favorable for the cultivation of M. officinalis with the intention of offering an objectively informed identification of suitable areas for the current and future development of this tree crop’s industry.

A study of nutritional assessment in paediatric patients with congenital heart disease in a tertiary care centre

: Congenital heart disease refers to any anatomical defect in the heart or major blood vessels present in children at birth. CHD (congenital heart disease) occurs in round about 1% of live births in developed countries. In developing countries due to poor resources, delayed diagnosis and surgery for CHD leads to a vicious cycle of congestive heart failure and respiratory infections, resulting in a high prevalence of preoperative malnutrition in patients with CHD. The incidence of congenital heart disease at birth is variable, incidence figures use to range between 5-8/1000 live births before the introduction of echocardiography but due to better diagnosis in today’s era many more milder forms are being detected, so the current estimates range from 8-12/1000 live births.: To assess the nutritional status in patients with CHD using clinical evaluation, anthropometry.: It is a cross-sectional observational stud. In our study a total of 75 cases of congenital heart disease were examined in a period of 18 months: Out of 75 patients 56 (74.66%) were <=5years and male predominance were seen. Most of the patient were having Acyanotic CHD: That there are multiple factors that are responsible for malnutrition in children with CHD including, poor socioeconomic strata, already poor health conditions in the general population, recurrent hospitalizations and recurrent lower respiratory tract infections.

Ion Channels in Odor Information Processing of Neural Circuits of the Vertebrate Olfactory Bulb.

Olfactory disorders and their associated complications present a considerable challenge to an individual's quality of life and emotional wellbeing. The current range of treatments, including surgical procedures, pharmacological interventions, and behavioral training, frequently proves ineffective in restoring olfactory function. The olfactory bulb (OB) is essential for odor processing and plays a pivotal role in the development of these disorders. Despite the acknowledged significance of ion channels in sensory functions and related pathologies, their specific involvement in OB remains unexplored. This review presents an overview of the functions of various ion channel families in regulating neuronal excitability, synaptic transmission, and the complex processes of olfactory perception. The objective of this review was to elucidate the role of ion channels in olfactory function, providing new insights into the diagnosis and treatment of olfactory dysfunction.

GLOW DISCHARGE IN HELIUM AND NITROGEN ATMOSPHERES AT STELLARATOR URAGAN-2M

Investigations of glow discharge on the Uragan-2M stellarator in helium and nitrogen atmospheres have been carried out. Studies were made in the range of discharge currents from 0.05 to 1 A and working gas pressure from 0.284 to 14.93 Pa. The current-voltage characteristics of the glow discharge were measured. The floating potential along the minor radius was measured using a single probe. In the optical emission spectrum of the plasma, spectral lines of excited He I atoms in the He atmosphere were observed. In the N2 atmosphere, spectral lines of excited molecules N2* and molecular ions N2+* were also registered.

Metabolic Consequences of Thyroidectomy and Patient-Centered Management.

Thyroidectomy has been post-operatively managed by hormone replacement therapy in order to satisfy the reference ranges of thyroid stimulating hormone (TSH) and thyroxine (T4) levels. While medication and standardized reference ranges have proven to be effective, many patients continue to report unintentional weight gain despite adequate amounts of treatment and levels of TSH and T4. Physicians, over the years, have become complacent to these "normal" ranges, and have ignored the metabolic consequences that are affecting thyroidectomy patients. This paper aims to redefine the approach to post-thyroidectomy clinical care by challenging the current standardized hormonal range values, exploring the gaps in thyroid hormone conversion, investigating the metabolic pathways of T3, considering the influence of inflammatory markers, and proposing the future for patient-centered management.

Invertebrate and fungal associations of the pastoral weed, Madagascar ragwort, Senecio madagascariensis Poir, in Northland, New Zealand, and implications for biocontrol

ABSTRACT Senecio madagascariensis Poir is now found in New Zealand colonising pastoral habitats north of a latitude 35.5°S. This prolific, continuous flowering, toxic perennial weed may not have reached its potential geographic range in New Zealand and is poorly controlled by herbicides. Prior to embarking on a biocontrol programme for this weed, we present a survey of invertebrates and diseases which found relatively few natural enemies and no specialised herbivores or plant pathogens in its current range in New Zealand. The most significant herbivorous insect pests were Hemipteran sap-suckers from 8 families. Percentage infestation of seedheads by the multivoltine tephritid fly, Sphenella rufriceps (Macquart) ranged from 16.7% to 49.8%. Fewer stems of S. madagascariensis were found in plants infected by the fungus, Puccinia lagenophorae Cooke. A search in Western Province (RSA) and in Madagascar for biocontrol control agents host specific to S. madagascariensis is planned.

Solutions for Retrofitting Catenary-Powered Transportation Systems Toward Greater Electrification in Smart Cities

Catenary-powered networks are expected to play a pivotal role in urban energy transition, due to the larger deployment of electric public transport, in-motion-charging (IMC) vehicles, and catenary-backed electric vehicle chargers. However, there are technical challenges that must be overcome to ensure the successful utilization of existing networks without compromising vehicle performance or compliance with network standards. This paper aims to validate the use of battery energy storage systems (BESS) built from second-life batteries as a means of retrofitting catenary-powered traction networks. The objective is to increase the network robustness without creating a negative impact on its overall operational efficiency. Consequently, more electrification projects can be implemented using the same network infrastructure without substantial modifications. Furthermore, a power management scheme is presented which allows the voltage and current range allowed in the catenary network and the BESS maximum charging rate to be controlled from user-defined values. The proposed control scheme is adept at customizing the BESS size for the specific application under consideration. Validation is performed on a case study of the trolleybus system in Bologna, Italy.

Merging Ajaniopsis (Asteraceae), an endangered genus endemic to the Tibet Plateau, into Artemisia: Implications for systematics and conservation

AbstractAjaniopsis is a monotypic genus of Asteraceae endemic to the Tibetan Plateau, growing on alpine scree slopes. It has been widely recognized as a separate genus and employed in many evolutionary and ecological analyses for its unique morphological characters. Despite being treated as an endangered species and once included in lists of key protected plant species, its systematic position has never been critically evaluated in a phylogenetic context. Furthermore, neither its past nor future distributional range has been assessed or predicted. In this study, we undertook morphological and molecular investigations to elucidate its systematics, and employed niche modeling to evaluate its historical, current, and potential future distributional range. Our phylogenetic analyses, based on the plastid genome and two nuclear DNA regions, show that Ajaniopsis is deeply nested in the mega‐diverse genus Artemisia. Morphological analysis indicates that its unique characters are also present in many distantly related species of Artemisia, implying significant convergent evolution. Consequently, Ajaniopsis can be reduced into Artemisia rather than being considered a distinct genus. Niche modeling reveals that its distributional range underwent a dramatic contraction ca. 3.3 Ma and is likely to continue shrinking in the future. This dramatic range contraction might be associated with climate changes and human activities in its unique habitat. Therefore, immediate in situ conservation is imperative for this critically endangered species, necessitating the establishment of a nature reserve on the Tibetan Plateau. Our studies highlight that it is beneficial to explore the evolutionary history of endangered species in detail when drafting conservation strategies.