Publications by authors named "Erika Levei"

Over three-quarters of Earth's surface exhibits extreme environments where life thrives under harsh physicochemical conditions. While prokaryotes have often been investigated in these environments, only recent studies have revealed the remarkable adaptability of eukaryotes, in particular fungi. This study explored the mycobiota of two meromictic hypersaline lakes, Ursu and Fără Fund, in Transylvania (Romania).

View Article and Find Full Text PDF

The determination of rare earth element (REE) content in different natural minerals is of high interest due to their extensive use in modern and sustainable technologies. The REEs occurring in natural zeolites are specific to each deposit. This study presents the validation and evaluation of the measurement uncertainty for the determination of REEs (Ce, Dy, Er, Eu, Gd, La, Lu, Nd, Pr, Sm, Y, and Yb) in natural zeolites using microwave-assisted acid digestion and inductively coupled plasma optical emission spectrometry (ICP-OES) after diffusive gradients in thin-film preconcentration.

View Article and Find Full Text PDF

A novel nanoporous adsorbent was obtained through the thermal treatment and chemical wash of the wasted crab shells (BC1) and characterized by various techniques. The structure of BC1 at the end of the treatments comprised a mixture of calcite and amorphous CaCO, as evidenced by X-ray diffraction and Fourier transform infrared absorption. The BET surface area, BET pore volume, and pore diameter were 250.

View Article and Find Full Text PDF

Mercury (Hg) is a toxic, non-essential element for living organisms, frequently present in high concentrations in soils from industrial areas. The total, dissolved, and labile Hg concentrations in garden soils and their accumulation in edible vegetables (onion, garlic, lettuce, and parsley) grown on contaminated soils in localities situated a former mining area were evaluated. The labile Hg fraction was estimated by diffusive gradient in thin films (DGT).

View Article and Find Full Text PDF
Article Synopsis
  • Beetles are widely found in caves and have developed unique adaptations to survive in these resource-scarce environments.
  • Research shows that the gut microbiota of these beetles is specific to their species and influenced by their evolutionary background and local cave conditions.
  • Different beetle diets and lifestyles lead to distinct microbial communities, with certain bacteria aiding in nutrient digestion and energy conservation, which are crucial for survival in caves.
View Article and Find Full Text PDF
Article Synopsis
  • Moonmilk is a cave deposit with historical medical and cosmetic uses, which is being studied for its antimicrobial properties.
  • Researchers analyzed five samples from caves with differing climates in Romania and Brazil, finding that calcite and dolomite were the main minerals present.
  • Genetic studies revealed diverse bacterial communities in the moonmilk, with significant unclassified phyla, orders, and genera, suggesting high potential for discovering new microorganisms with useful applications.
View Article and Find Full Text PDF

The expansion of the construction industry requires large quantities of construction materials; therefore, the utilization of alternative raw materials that reduce the environmental impact and enhance the quality of the construction materials has received increasing interest. The comparative performance of 1% Dynamon SR3 or Dynamon SR41 superplasticizers on the properties of cement paste with 1 wt.% vine shoot waste addition (VSW) was investigated after 28 days using Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and solid-state Al and Si nuclear magnetic resonance (NMR) spectroscopy.

View Article and Find Full Text PDF

The photosynthetic pigments, protein, macro and microelements concentrations, and fatty acids composition of , a free-floating aquatic plant, were analyzed after exposure to Hoagland nutrient solution containing 1, 3, and 5 mg/L Li. The Li content of grew exponentially with the Li concentration in the Hoagland nutrient solution. The exposure to Li did not induce significant changes in Na, Mg, K, Cu, and Zn content but enhanced the Ba, Cr, Mn, Ni and Mo absorption in .

View Article and Find Full Text PDF

This work presents the effect of monovalent (Ag, Na), divalent (Ca, Cd), and trivalent (La) metal ion doping and annealing temperature (500, 800, and 1200 °C) on the structure, morphology, and magnetic properties of MnFeO/SiO ceramic nanocomposites synthesized via sol-gel method. Fourier-transform infrared spectroscopy confirms the embedding of undoped and doped MnFeO nanoparticles in the SiO matrix at all annealing temperatures. In all cases, the X-ray diffraction (XRD) confirms the formation of MnFeO.

View Article and Find Full Text PDF
Article Synopsis
  • Karst aquifers are crucial sources of drinking water but are vulnerable to contamination due to their porous nature; this study investigates the stable core microbiome in karst springs in Romania over one year.
  • Researchers used advanced techniques, including 16S rRNA gene sequencing and antibiotic resistance gene quantification, to identify a consistent bacterial community mainly consisting of Pseudomonadota, Bacteroidota, and Actinomycetota, many of which showed signs of contamination with fecal bacteria and pathogens.
  • The study also found high levels of antibiotic resistance genes linked to various pollutants and proposed specific bacterial groups as potential indicators for monitoring pollution in these sensitive water sources.
View Article and Find Full Text PDF

CoFeO is a promising functional material for various applications. The impact of doping with different cations (Ag, Na, Ca, Cd, and La) on the structural, thermal, kinetics, morphological, surface, and magnetic properties of CoFeO nanoparticles synthesized via the sol-gel method and calcined at 400, 700 and 1000 °C is investigated. The thermal behavior of reactants during the synthesis process reveals the formation of metallic succinates up to 200 °C and their decomposition into metal oxides that further react and form the ferrites.

View Article and Find Full Text PDF
Article Synopsis
  • * The specific gut bacteria in these beetles are linked to their diet and evolutionary history, indicating a coevolution between the beetles and their microbial communities influenced by local conditions.
  • * Different species of cave beetles host various bacteria that aid in decomposing organic materials, highlighting their adaptation strategies for survival in caves through fermentation and reduced metabolic activity.
View Article and Find Full Text PDF
Article Synopsis
  • Karst caves have unique environments with constant temperature, high humidity, and low nutrient levels, making them important for studying microbial diversity and biogeochemical processes.
  • The research focused on the microbial communities in Leșu Cave, utilizing techniques like 16S rRNA gene sequencing and physiological profiling to assess microbial diversity and their preferences for organic substrates.
  • Results showed that while there was overall similarity in bacterial phyla, specific sites within the cave exhibited unique bacterial communities based on environmental conditions, with nutrient sources influencing their distribution patterns.
View Article and Find Full Text PDF

(CoZnNiFeO)(SiO) samples obtained by embedding CoZnNiFeO nanoparticles in SiO in various proportions were synthesized by sol-gel process and characterized using thermal analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma optical emission spectrometry, and magnetic measurements. Poorly crystalline Co-Zn-Ni ferrite at low annealing temperatures (500 °C) and highly crystalline Co-Zn-Ni ferrite together with traces of crystalline FeSiO (800 °C) and SiO (tridymite and cristobalite) (1200 °C) were obtained. At 1200 °C, large spherical particles with size increasing with the ferrite content (36-120 nm) were obtained.

View Article and Find Full Text PDF

A mobile monitoring campaign was conducted (by bicycle) to assess the black carbon (BC) concentrations in Cluj-Napoca city, Romania, in 2020, before, during and after COVID-19 lock-down. Over the entire study period, the BC concentrations ranged between 1.0 and 25.

View Article and Find Full Text PDF

This study's objective was to separate cellulose, hemicellulose, and lignin after high-pressure supercritical carbon dioxide pretreatment for further valorization. The study investigated the supercritical carbon dioxide pretreatment of apple orchard waste at temperatures of 160-200 °C, for 15-45 min, at a pressure of 10 MPa. Response Surface Methodology (RSM) was used to optimize the supercritical process and to improve its efficiency.

View Article and Find Full Text PDF

The structure, morphology, and sonophotocatalytic activity of Ni-Zn-Co ferrite nanoparticles, embedded in a SiO matrix and produced by a modified sol-gel method, followed by thermal treatment, were investigated. The thermal analysis confirmed the formation of metal succinate precursors up to 200 °C, their decomposition to metal oxides and the formation of Ni-Zn-Co ferrites up to 500 °C. The crystalline phases, crystallite size and lattice parameter were determined based on X-ray diffraction patterns.

View Article and Find Full Text PDF

The new context of the intensive use of lithium-based batteries led to increased production of Li and Li-containing wastes. All these activities are potential sources of environmental pollution with Li. However, the negative impact of Li on ecosystems, its specific role in the plants' development, uptake mechanism, and response to the induced stress are not fully understood.

View Article and Find Full Text PDF

This study aimed to investigate the ways in which the thermal behavior, composition, and volatile compound contents of roasted coffee beans depend on variety and roasting intensity. The thermal analysis revealed various transformations in coffee composition, namely, drying, water loss, and decomposition of polysaccharides, lipids, amino acids, and proteins. The results showed that volatile compounds are released differently in coffee depending on coffee type and degree of roasting.

View Article and Find Full Text PDF

The ability of natural zeolite amendment to reduce the uptake of potentially toxic elements (PTEs) by lettuce, spinach and parsley was evaluated using pot experiments. PTE concentrations in roots and shoots, as well as the pseudo total (PT), water soluble (WS) and bioavailable (BA) PTE fractions in the amended soils, were assessed. Although the PT PTE concentration was high, the WS fraction was very low (<0.

View Article and Find Full Text PDF
Article Synopsis
  • Movile Cave in SE Romania is a unique ecosystem that relies on hydrogen sulfide-rich groundwater, similar to deep-sea hydrothermal systems, and past research has mainly focused on the water and surface microbial mats.
  • A study using advanced genomic techniques identified 106 high-quality genomes from cave sediments, uncovering diverse bacterial and archaeal communities, with key metabolic functions like carbon fixation and sulfur oxidation detected.
  • Results indicate that the cave's primary production potential extends beyond the water, highlighting complex interactions and metabolic exchanges among microbes in sediment environments.
View Article and Find Full Text PDF

The structural, morphological and magnetic properties of MFeO (M = Co, Ni, Zn, Cu, Mn) type ferrites produced by thermal decomposition at 700 and 1000 °C were studied. The thermal analysis revealed that the ferrites are formed at up to 350 °C. After heat treatment at 1000 °C, single-phase ferrite nanoparticles were attained, while after heat treatment at 700 °C, the CoFeO was accompanied by CoO and the MnFeO by α-FeO.

View Article and Find Full Text PDF
Article Synopsis
  • Muierilor Cave, a significant show cave in Romania, recently revealed a new chamber featuring unique yellow calcite crystals and various sediment types linked to fossil bones and guano.
  • Samples taken from the chamber showed a distinct microbial community influenced by high phosphate levels, sourced from hydroxyapatite minerals and organic deposits like guano, suggesting a complex ecological relationship.
  • Notably, the study discovered that about 0.7% of the identified bacteria were unknown, with nearly half not previously reported in caves or guano, highlighting the need for ongoing monitoring of microbial diversity for potential impacts on human health and biotechnological applications.
View Article and Find Full Text PDF

Sol-gel route followed by thermal treatment was used to produce NiFeO doped with transition metal ions (Zn, Mn, Co). The structural, morphological, and magnetic properties of the doped NiFeO were compared with those of virgin NiFeO. The metal-glyoxylates' formation and decomposition as well as the thermal stability of the doped and virgin ferrites were assessed by thermal analysis.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessiong2i7nouhi2ntsqicj51opdu4uqomh4ae): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once