Complex Species Research Articles

Three novel Enterobacter cloacae bacteriophages for therapeutic use from Ghanaian natural waters

Infections caused by multidrug-resistant (MDR) bacteria are a growing global concern. Enterobacter cloacae complex (ECC) species are particularly adept at developing antibiotic resistance. Phage therapy is proposed as an alternative treatment for pathogens that no longer respond to antibiotics. Unfortunately, ECC phages are understudied when compared to phages of many other bacterial species. In this Ghanaian-Finnish study, we isolated two ECC strains from ready-to-eat food samples and three novel phages from natural waters against these strains. We sequenced the genomic DNA of the novel Enterobacter phages, fGh-Ecl01, fGh-Ecl02, and fGh-Ecl04, and assessed their therapeutic potential. All of the phages were found to be lytic, easy to propagate, and lacking any toxic, integrase, or antibiotic resistance genes and were thus considered suitable for therapy purposes. They all were found to be related to T4-type viruses: fGh-Ecl01 and fGh-Ecl04 to karamviruses and fGh-Ecl02 to agtreviruses. Testing of Finnish clinical ECC strains showed promising susceptibility to these novel phages. As many as 61.1% of the strains were susceptible to fGh-Ecl01 and fGh-Ecl04, and 7.4% were susceptible to fGh-Ecl02. Finally, we investigated the susceptibility of the newly isolated ECC strains to three antibiotics – meropenem, ciprofloxacin, and cefepime – in combination with the novel phages. The use of phages and antibiotics together had synergistic effects. When using an antibiotic-phage combination, even low concentrations of antibiotics fully inhibited the growth of bacteria.

The General Law of Being, Article 3: The Ultimate Cause of Evolution

This is the third article in a series about the General Law of Being, a science philosophy that was introduced by Chinese scholar Wang Dongyue twenty years ago and then expanded upon by Chen Ye, who linked it to other scientific and philosophical traditions as well as to Big History. We encourage readers to review the previous two articles in the Journal of Big History, volume 6, issues 1 and 2. Article 1 addressed how all entities in the universe – ‘beings’ – are finite and dependent. Horizontally, their existence is realized through the structural coupling of their interactive-quality with other being(s)’s interactable-quality, and vertically through the superposition of their historical structural-coupling states. Article 2 reveals the interplay of the two opposite forces that govern evolution – conservation and variation. This evolution / variation progress occurs through the differentiation of beings, level by level – each level of organization results from differentiation of beings at a lower level of organization, with the ‘adaptation task’ distributed to specialized roles at higher levels. However, this ascent comes with a trade-off – the existence of a higher-level being depends on an increasing number of conditions. These conditions not only facilitate its functioning but also expose it to greater risks, which means that higher-level beings have weaker, or more unstable structures. Meanwhile, the increasing number of conditions perplexes the sense-reaction process, giving rise to more advanced cognitive patterns to coordinate the process. In this article, we first examine the situation of the most sophisticated ‘natural’ structure formed by the most complex species – human society, by applying the fundamental principles discussed in Articles 1 and 2. We then systematize various clues in macro-evolution and based on theories previously outlined, we build our model of evolution to address the ultimate driving force behind evolution.

ALMA-IMF

Context. The star formation process leads to an increased chemical complexity in the interstellar medium. Sites associated with high-mass star and cluster formation exhibit a so-called hot core phase, characterized by high temperatures and column densities of complex organic molecules. Aims. We aim to systematically search for and identify a sample of hot cores toward the 15 Galactic protoclusters of the ALMA-IMF Large Program and investigate their statistical properties. Methods. We built a comprehensive census of hot core candidates toward the ALMA-IMF protoclusters based on the detection of two CH3OCHO emission lines at 216.1 GHz. We used the source extraction algorithm GExt2D to identify peaks of methyl formate (CH3OCHO) emission, a complex species commonly observed toward sites of star formation. We performed a cross-matching with the catalog of thermal dust continuum sources from the ALMA-IMF 1.3 mm continuum data to infer their physical properties. Results. We built a catalog of 76 hot core candidates with masses ranging from ~0.2 M⊙ to ~80 M⊙, of which 56 are new detections. A large majority of these objects, identified from methyl formate emission, are compact and rather circular, with deconvolved full width at half maximum (FWHM) sizes of ~2300 au on average. The central sources of two target fields show more extended, but still rather circular, methyl formate emission with deconvolved FWHM sizes of ~6700 au and 13 400 au. About 30% of our sample of methyl formate sources have core masses above 8 M⊙ and range in size from ~1000 au to 13 400 au, which is in line with measurements of archetypical hot cores. The origin of the CH3OCHO emission toward the lower-mass cores may be explained as a mixture of contributions from shocks or may correspond to objects in a more evolved state (i.e., beyond the hot core stage). We find that the fraction of hot core candidates increases with the core mass, suggesting that the brightest dust cores are all in the hot core phase. Conclusions. Our results suggest that most of these compact methyl formate sources are readily explained by simple symmetric models, while collective effects from radiative heating and shocks from compact protoclusters are needed to explain the observed extended CH3OCHO emission. The large fraction of hot core candidates toward the most massive cores suggests that they rapidly enter the hot core phase and that feedback effects from the forming protostar(s) impact their environment on short timescales.

An active learning workflow for predicting hydrogen atom adsorption energies on binary oxides based on local electronic transfer features

Machine learning combined with density functional theory (DFT) enables rapid exploration of catalyst descriptors space such as adsorption energy, facilitating rapid and effective catalyst screening. However, there is still a lack of models for predicting adsorption energies on oxides, due to the complexity of elemental species and the ambiguous coordination environment. This work proposes an active learning workflow (LeNN) founded on local electronic transfer features (e) and the principle of coordinate rotation invariance. By accurately characterizing the electron transfer to adsorption site atoms and their surrounding geometric structures, LeNN mitigates abrupt feature changes due to different element types and clarifies coordination environments. As a result, it enables the prediction of ∗H adsorption energy on binary oxide surfaces with a mean absolute error (MAE) below 0.18 eV. Moreover, we incorporate local coverage (θl) and leverage neutral network ensemble to establish an active learning workflow, attaining a prediction MAE below 0.2 eV for 5419 multi-∗H adsorption structures. These findings validate the universality and capability of the proposed features in predicting ∗H adsorption energy on binary oxide surfaces.

Genomic Study of High-Risk Clones of Enterobacter hormaechei Collected from Tertiary Hospitals in the United Arab Emirates.

Enterobacter hormaechei has emerged as a significant pathogen within healthcare settings due to its ability to develop multidrug resistance (MDR) and survive in hospital environments. This study presents a genome-based analysis of carbapenem-resistant Enterobacter hormaechei isolates from two major hospitals in the United Arab Emirates. Eight isolates were subjected to whole-genome sequencing (WGS), revealing extensive resistance profiles including the blaNDM-1, blaOXA-48, and blaVIM-4 genes. Notably, one isolate belonging to ST171 harbored dual carbapenemase genes, while five isolates exhibited colistin resistance without mcr genes. The presence of the type VI secretion system (T6SS), various adhesins, and virulence genes contributes to the virulence and competitive advantage of the pathogen. Additionally, our isolates (87.5%) possessed ampC β-lactamase genes, predominantly blaACT genes. The genomic context of blaNDM-1, surrounded by other resistance genes and mobile genetic elements, highlights the role of horizontal gene transfer (HGT) in the spread of resistance. Our findings highlight the need for rigorous surveillance, strategic antibiotic stewardship, and hospital-based WGS to manage and mitigate the spread of these highly resistant and virulent pathogens. Accurate identification and monitoring of Enterobacter cloacae complex (ECC) species and their resistance mechanisms are crucial for effective infection control and treatment strategies.

Increased lipogenesis and lipidosis of gallbladder epithelium in dogs with gallbladder mucocele formation.

Gallbladder disease in people is frequently associated with disorders of lipid metabolism and metabolic syndrome. A recently emergent gallbladder disease of dogs, referred to as mucocele formation, is characterized by secretion of abnormal mucus by the gallbladder epithelium and is similarly associated with hyperlipidemia, endocrinopathy, and metabolic dysfunction. The cause of gallbladder mucocele formation in dogs is unknown. A prospective case-controlled study was conducted to gain insight into disease pathogenesis by characterization of plasma lipid abnormalities in 18 dogs with gallbladder mucocele formation and 18 age and breed matched control dogs using direct infusion mass spectrometry for complex plasma lipid analysis. This analysis was complemented by histochemical and ultrastructural examination of gallbladder mucosa from dogs with gallbladder mucocele formation and control dogs for evidence of altered lipid homeostasis of the gallbladder epithelium. Gallbladder mucocele formation in dogs carried a unique lipidomic signature of increased lipogenesis impacting 50% of lipid classes, 36% of esterified fatty acid species, and 11% of complex lipid species. Broad enrichment of complex lipids with palmitoleic acid (16:1) and decreased abundance within complex lipids of presumptive omega-3 fatty acids eicosapentaenoic (20:5) and docosahexaenoic (22:6) was significant. Severe lipidosis of gallbladder epithelium pinpoints the gallbladder as involved causally or consequently in abnormal lipid metabolism. Our study supports a primary increase in lipogenesis in dogs with mucocele formation and abnormal gallbladder lipid metabolism in disease pathogenesis.

One Health and sex and gender-related perspective in the ecosystem: Interactions among drivers involved in the risk of leptospirosis in Europe. A scoping review

Leptospirosis has a complex transmission, involving rodents and many species of domestic and wild animals. Carrier animals spread leptospires, contaminating soil and water, the main sources of human infection. The risk of infection is modulated by socio-economic factors, environment and host animals and has changed, historically linked to agriculture but now prevalent in recreational environments. Leptospirosis also reveal gender-specific exposure patterns that determine infection risks. Emphasizing the interconnectedness of humans, animals, and the environment, the One Health approach highlights the ecosystem dynamics through which leptospires interact with hosts and abiotic factors, ensuring their survival and transmission.We advocate for integrating gender considerations into the ecosystem dynamics of complex zoonoses, such as leptospirosis, through a One Health perspective. This approach, yet to be fully explored, may enhance our understanding of the infection and its modulating factors. A scoping review of the literature was conducted across Embase and Pubmed databases to collect information on sex and gender-specific drivers, sources of infections, environmental drivers, and related risks of leptospirosis. Quantitative data were extracted from the articles selected according to a list of criteria, and analyzed to discern sex and gender disparities and identify primary drivers of leptospirosis. We confirmed that the excess of male leptospirosis cases described in many parts of the world is also present in Europe. Furthermore, we identified environmental and sociocultural drivers and hypothesized their interactions between and within human, animal, and environmental sectors. These interactions modulate direct and indirect exposure to Leptospira, heightening infection risks across the ecosystem. Based on our findings, utilizing leptospirosis as a model, we advocate for integrating One Health and gender approaches in public health practices to better plan and implement more effective and timely intervention measures.

The Chlorido-Bismuth Dication: A Potent Lewis Acid Captured in a Hepta-Coordinate Species with a Stereochemically Active Lone Pair.

The stabilization of simple, highly reactive cationic species in molecular complexes represents an important strategy to isolate and characterize compounds with uncommon or even unprecedented structural motifs and properties. Here we report the synthesis, isolation, and full characterization of chlorido-bismuth dications, stabilized only by monodentate dimethylsulfoxide (dmso) ligands: [BiCl(dmso)6][BF4]2 (1) and [BiCl(μ2-dmso)(dmso)4]2[BF4]4 (2). These compounds show unusual distorted pentagonal bipyramidal coordination geometries along with high Lewis acidities and have been analyzed by multinuclear NMR spectroscopy, elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, and density functional theory calculations. Attempts to generate the bromido- and iodido-analogs gave dmso-stabilized tricationic bismuth species.

Orchidinae-205: A new genome-wide custom bait set for studying the evolution, systematics, and trade of terrestrial orchids.

Terrestrial orchids are a group of genetically understudied, yet culturally and economically important plants. The Orchidinae tribe contains many species that produce edible tubers that are used for the production of traditional delicacies collectively called 'salep'. Overexploitation of wild orchids in the Eastern Mediterranean and Western Asia threatens to drive many of these species to extinction, but cost-effective tools for monitoring their trade are currently lacking. Here we present a custom bait kit for target enrichment and sequencing of 205 novel genetic markers that are tailored to phylogenomic applications in Orchidinae s.l. A subset of 31 markers capture genes putatively involved in the production of glucomannan, a water-soluble polysaccharide that gives salep its distinctive properties. We tested the kit on 73 taxa native to the area, demonstrating universally high locus recovery irrespective of species identity, that exceeds the total sequence length obtained with alternative kits currently available. Phylogenetic inference with concatenation and coalescent approaches was robust and showed high levels of support for most clades, including some which were previously unresolved. Resolution for hybridizing and recently radiated lineages remains difficult, but could be further improved by analysing multiple haplotypes and the non-exonic sequences captured by our kit, with the promise to shed new light on the evolution of enigmatic taxa with a complex speciation history. Offering a step-up from traditional barcoding and universal markers, the genome-wide custom loci targeted by Orchidinae-205 are a valuable new resource to study the evolution, systematics and trade of terrestrial orchids.

Chelation of rare earth metals by perfluorinated β-diketones bearing nitrogen heterocycles rings

Aqueous equilibria of three substituted perfluorinated 1,3-diketones with pyrrole, pyrazole, and pyridine rings have been extensively studied in aqueous solutions. Thermodynamic characteristics of dissociation, protonation, and chelation processes have been investigated by UV–Vis spectroscopy using non-linear regression analysis. Acid-base parameters were discovered in the acidity range from highly acidic media (C(HCl) = 10 M) to alkaline pH region. Dissociation constants (pKa) have been determined in glycine-HCl, phosphate-citrate, and TRIS-HCl buffered media. Protonation activities were studied by the Cox-Yates approach in concentrated hydrochloric acid solutions. First formation constants of ML complex species with trivalent ions of Sc3+, Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, Tb3+, Ho3+, Er3+, Tm3+, Yb3+, and Lu3+ have been obtained in the pH within 3.0–5.6 (I = 0.5 M, NaCl). True stability constants have been calculated using determined acid-base parameters considering side reactions. The “True” formation constants lie from 3.7 to 6.9 logarithmic units and have a linear relationship with the ionic (Coulomb) potential of metals. DFT and TD-DFT simulations have been performed for the modeling of the data obtained.

Rainfall seasonality shapes microbial assembly and niche characteristics in Yunnan Plateau lakes, China

Microorganisms are crucial components of freshwater ecosystems. Understanding the microbial community assembly processes and niche characteristics in freshwater ecosystems, which are poorly understood, is crucial for evaluating microbial ecological roles. The Yunnan Plateau lakes in China represent a freshwater ecosystem that is experiencing eutrophication due to anthropogenic activities. Here, variation in the assembly and niche characteristics of both prokaryotic and microeukaryotic communities was explored in Yunnan Plateau lakes across two seasons (dry season and rainy season) to determine the impacts of rainfall and environmental conditions on the microbial community and niche. The results showed that the environmental heterogeneity of the lakes decreased in the rainy season compared to the dry season. The microbial (bacterial and microeukaryotic) α-diversity significantly decreased during the rainy season. Deterministic processes were found to dominate microbial community assembly in both seasons. β-Diversity decomposition analysis revealed that microbial community compositional dissimilarities were dominated by species replacement processes. The co-occurrence networks indicated reduced species complexity for microbes and a destabilized network for prokaryotes prior to rainfall, while the opposite was found for microeukaryotes following rainfall. Microbial niche breadth decreased significantly in the rainy season. In addition, lower prokaryotic niche overlap, but greater microeukaryotic niche overlap, was observed after rainfall. Rainfall and environmental conditions significantly affected the microbial community assembly and niche characteristics. It can be concluded that rainfall and external pollutant input during the seasonal transition alter the lake environment, thereby regulating the microbial community and niche in these lakes. Our findings offer new insight into microbiota assembly and niche patterns in plateau lakes, further deepening the understanding of freshwater ecosystem functioning.

Variation in symptoms and morphology of Fusarium spp. on shallot associated with basal plate rot disease in Brebes District, Central Java Province, Indonesia

Abstract. Marianah L, Nawangsih AA, Munif A, Giyanto, Tondok ET. 2024. Variation in symptoms and morphology of Fusarium spp. on shallot associated with basal plate rot disease in Brebes District, Central Java Province, Indonesia. Biodiversitas 25: 2198-2208. Basal plate rot disease is an important disease of shallots that causes losses in the field and storage. The disease is caused by Fusarium complex species, with different levels of virulence and host susceptibility. The six species of Fusarium spp. reported to cause basal plate rot disease of onion were F. oxysporum f.sp. cepae, F. proliferatum, F. redolens, F. solani, F. acutatum and F. tricinctum. Information about the variation in symptoms and morphology of fungi that cause basal plate rot disease on shallots, especially in Indonesia, is still very limited. Besides, the species that cause basal plate rot disease on shallots has not been molecularly confirmed using specific primers. The objective of this study was to isolate, identify, and study the variation in symptoms of the fungus associated with basal plate rot disease. The fungi were isolated from shallot plants symptomatic of basal plate rot disease collected from Brebes, Central Java Province. Eight isolates of Fusarium with different morphologies were successfully isolated and identified. Five isolates were identified as F. solani (isolate BC1, BC2, BC3, BBS1, and BBS4), two isolates as F. oxysporum f.sp. cepae (isolate BC4 and BBS6) and one isolate F. proliferatum (isolate BBS5). All eight isolates were pathogenic on shallots with different levels of virulence and symptom variations. BC4 isolate had the highest level of virulence, resulting in plant death, and was identified as F. oxysporum f.sp. cepae.

Screening Conductive MXenes for Lithium Polysulfide Adsorption

AbstractMXenes are promising passive components that enable lithium‐sulfur batteries (LSBs) by effectively trapping lithium polysulfides (LiPSs) and facilitating surface‐mediated redox reactions. Despite numerous studies highlighting the potential of MXenes in LSBs, there are no systematic studies of MXenes’ composition influence on polysulfide adsorption, which is foundational to their applications in LSB. Here, a comprehensive investigation of LiPS adsorption on seven MXenes with varying chemistries (Ti2CTx, Ti3C2Tx, Ti3CNTx, Mo2TiC2Tx, V2CTx, Nb2CTx, and Nb4C3Tx), utilizing optical and analytical spectroscopic methods is performed. This work reports on the influence of polysulfide concentration, interaction time, and MXenes’ chemistry (transition metal layer, carbide and carbonitride inner layer, surface terminations and structure) on the amount of adsorbed LiPSs and the adsorption mechanism. These findings reveal the formation of insoluble thiosulfate and polythionate complex species on the surfaces of all tested MXenes. Furthermore, the selective adsorption of lithium and sulfur, and the extent of conversion of the adsorbed species on MXenes varied based on their chemistry. For instance, Ti2CTx exhibits a strong tendency to adsorb lithium ions, while Mo2TiC2Tx is effective in trapping sulfur by forming long‐chain polythionates. The latter demonstrates a significant conversion of intermediate polysulfides into low‐order species. This study offers valuable guidance for the informed selection of MXenes in various functional components benefiting the future development of high‐performance LSBs.

Studies on the interaction of aquahydroxocobinamide with 5-aminotetrazole

Here we show that 5-aminotetrazole (ATZ) is capable of moderately strong binding with aquahydroxocobinamide ((H2O)(HO-)Cbi). At pH 7.4, 25.0 °C, the reaction of (H2O)(HO-)Cbi with a two-fold excess of ATZ produces a mixture of complexes with one (a major fraction) having two ATZ ligands, and a minor fraction of (H2O)(HO-)Cbi remains unreacted. ATZ complexation with (H2O)(HO-)Cbi proceeds rapidly, i.e. rate constants for binding of the first and second ATZ molecules are (4.3 ± 0.5)×103 and (5.8 ± 0.4)×102 M−1 s−1 (pH 7.4, 25.0 °C), respectively. The addition of ATZ to (H2O)(HO-)Cbi notably decreases the extent of Cbi species complexation with bovine serum albumin and the rate of Cbi(III) species reduction to Cbi(II) by glutathione, whereas the rates of reactions with cyanide and hydrogen sulfide remain relatively high. Thus, ATZ may prevent (H2O)(HO-)Cbi retention by proteins and its involvement in side redox reactions upon introduction in the human body, which explains the high absorption of the Cbi-ATZ complex during intramuscular injection and its high efficacy as an antidote.

Probabilistic microkinetic modeling: Species balance equations for a catalyst surface containing multiple short-range order parameters to capture spatial correlations.

Adsorbed molecules on a catalyst almost always arrange themselves in a manner that is far from perfectly random, which gives rise to spatial correlations. These correlations are a result of the interactions between the adsorbed species (adspecies) as well as elementary processes such as diffusion and reaction events that shape the adspecies arrangements. Despite their importance, spatial correlations are usually ignored while writing species balance equations for the modeling of heterogeneous catalytic systems. Recently, we have introduced a probabilistic microkinetic modeling (p-MKM) framework that aims at incorporating spatial correlations in the form of a short-ranged order (SRO) parameter into species balance equations. Here, we extend the approach to catalytic systems of higher complexity, namely, longer interactions and multiple species. This is made possible by including multiple pair probabilities in the p-MKM model for the first time. The interplay between different SRO parameters is probed. An important consideration is how many pair probabilities should be included to capture the underlying complexity with sufficient accuracy.

Evaluation of CHROMagar™ B. cepacia agar for the detection of Burkholderia cepacia complex species from sputum samples of patients with cystic fibrosis

IntroductionBurkholderia cepacia complex (BCC) are non-fermenting Gram-negative bacteria that can chronically colonize the lungs of people with cystic fibrosis (pwCF), causing a severe and progressive respiratory failure, post-transplant complications and epidemic outbreaks. Therefore, rapid and accurate identification of these bacteria is relevant for pwCF, in order to facilitate early eradication and prevent chronic colonization. However, BCCs are often quite difficult to detect on culture media as they have a slow growth rate and can be hidden by other fast-growing microorganisms, including Pseudomonas aeruginosa and filamentous fungi.Material and methodsWe evaluated the sensitivity of CHROMagar™ B. cepacia agar using 11 isolates from a well-characterized BCC collection, using BCA agar (Oxoid, UK) as a gold standard. We also studied 180 clinical sputum samples to calculate positive (PPV) and negative (NPV) predictive values. Furthermore, we used three of the well-characterized BCC isolates to determine the limit of detection (LOD).ResultsEleven isolates grew on CHROMagar™ B. cepacia at 37ºC after 48 h. The NPV and PPV of CHROMagar™ B. cepacia were 100% and 87.5%, respectively. The LOD of CHROMagar™ B. cepacia was around 1 × 103 CFU/ml, requiring a ten-fold dilution lower bacterial load than BCA for BCC detection.ConclusionCHROMagar™ B. cepacia agar proved to have a very good sensitivity and specificity for the detection of clinical BCCs. Moreover, the chromogenic nature of the medium allowed us to clearly differentiate BCC from other Gram-negative species, filamentous fungi and yeasts, thereby facilitating the identification of contaminants.

Molecular Epidemiology and Antifungal Susceptibility Profile in Nakaseomyces glabrata Species Complex: A 5-Year Countrywide Study.

The current study aimed to identify Iranian Nakaseomyces (Candida) glabrata complex species in the clinical isolates and determine their antifungal susceptibility profile. In total, 320 N. glabrata clinical isolates were collected from patients hospitalized in different geographical regions of Iran. The initial screening was performed by morphological characteristics on CHROMagar Candida. Each isolate was identified by targeting the D1/D2 rDNA using a multiplex-PCR method. To validate the mPCR method and determine genetic diversity, the ITS-rDNA region was randomly sequenced in 40 isolates. Additionally, antifungal susceptibility was evaluated against nine antifungal agents following the CLSI M27-A4 guidelines. All clinical isolates from Iran were identified as N. glabrata. The analysis of ITS-rDNA sequence data revealed the presence of eight distinct ITS clades and 10 haplotypes among the 40 isolates of N. glabrata. The predominant clades identified were Clades VII, V, and IV, which respectively accounted for 22.5%, 17.5%, and 17.5% isolates. The widest MIC ranges were observed for voriconazole (0.016-8 μg/mL) and isavuconazole (0.016-2 μg/mL), whereas the narrowest ranges were seen with itraconazole and amphotericin B (0.25-2 μg/mL). Haplotype diversity can be a valuable approach for studying the genetic diversity, transmission patterns, and epidemiology of the N. glabrata complex.

Taxonomic Revision of the Polypodiaceous Genera of India-Iv Polypodium Lineare Complex and Allied Species

The Asiatic genus Lepisorus (J. Smith) Ching consists of about 25 species, majority of which are known from the Sino-Himalayan region. The present paper deals with the taxonomy of Lepisorus species which belong to Polypodium lineare complex. Our studies have revealed that the Himalayan and South Indian material generally placed under P. lineare is a collection of large and variable types and this material has been sorted out into L. nudus (Hook.) Ching, L. amaurolepida(Sledge).Bir & Trikha, L. bicolor Ching, L. pseudonudus Ching, L. angustus Ching, L. ussuriensis (Regel & Maack) Ching, L. contortus Ching and L. tkunbergianus (Kaulf.) Ching. Out of these L. ussuriensis, L. contortus and L. bicolor are new records from the Indian region. Several of these species are sympatric in distribution and are closely allied in the form of the laminae. These are separable mainly on the basis of the outline and structure of scales and spores.

Ion pair sites for efficient electrochemical extraction of uranium in real nuclear wastewater

Electrochemical uranium extraction from nuclear wastewater represents an emerging strategy for recycling uranium resources. However, in nuclear fuel production which generates the majority of uranium-containing nuclear wastewater, fluoride ion (F−) co-exists with uranyl (UO22+), resulting in the complex species of UO2Fx and thus decreasing extraction efficiency. Herein, we construct Tiδ+-PO43− ion pair extraction sites in Ti(OH)PO4 for efficient electrochemical uranium extraction in wastewater from nuclear fuel production. These sites selectively bind with UO2Fx through the combined Ti-F and multiple O-U-O bonds. In the uranium extraction, the uranium species undergo a crystalline transition from U3O7 to K3UO2F5. In real nuclear wastewater, the uranium is electrochemically extracted with a high efficiency of 99.6% and finally purified as uranium oxide powder, corresponding to an extraction capacity of 6829 mg g−1 without saturation. This work paves an efficient way for electrochemical uranium recycling in real wastewater of nuclear production.

Electrochemical characterization of binder effect in natural magnetite electrodes for fluoride removal of well water

This work presents the study of the behavior of magnetite in fluoride electroadsorption. A concern in the fluoride electroadsorption is related to the type of binder, fluoride concentration, pH, and coexisting ions. A graphite/Nafion/magnetite electrode increases the specific capacitance of the surface favoring the surface complexation of anions due to the increase in the effective adsorption surface in this system. There is a tendency to increase the specific capacitance when the concentration and pH increase. The anionic affinity of the system is directly related to the nature of the ions and the hydrated ionic radius, in ions with the same charge, a lower hydrated radius results in a greater possibility of surface complexation. Excess OH− groups increase the accumulation of charge in the double layer, making the surface complexation of the anionic species towards the surface difficult. The selectivity trend is: CO32− > SO42− > F− > Cl− > NO3−.