2024 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2024

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Employment of University Graduates in the Era of Digitalization and Artificial Intelligence: Challenges and Prospects
- Nina Rizun
- Halina Ryzhkova
- Irena Pawłyszyn
- Charalampos Harris Alexopoulos
2024
Digital technologies are profoundly reshaping the labor market, causing structural shifts in the economy and altering the nature of work. These changes have significant implications for youth employment, exacerbating the issue of unemployment. This paper delves into the importance of graduate employment in contemporary society, with a particular focus on the influence of digital technologies and Artificial Intelligence. The authors explore the challenges associated with digital transformation and underscore the pivotal role of universities in nurturing skills essential for successful employment. The paper also looks at the prospects for graduates in this dynamic environment, which offers both challenges and opportunities for career growth. This research may be relevant for developing directions to improve the preparation of students for the rapidly changing labor market
Emulsifying blends based on natural fats for eco-design of O/W emulsions
- Patrycja Szumała
- Elżbieta Pyrz
2024 JOURNAL OF CLEANER PRODUCTION
Emulsifier blends are most often used to stabilize and modulate the properties of cosmetic and pharmaceutical emulsions, such as skin care or application-related consistency. However, the rational design of such emulsifier blends is often not well understood, especially when their ingredients are natural raw materials. This study aimed to analyze the influence of natural fatty ingredients selected as emulsifiers on the emulsion properties. For this purpose, the stability, microstructure and rheological properties of the produced emulsions were monitored during their storage. The effect of five blends containing fatty alcohols, cetyl palmitate, beeswax, avocado butter and one typical emulsifier, i.e. sorbitan oleate, in various weight proportions, was analyzed. Even though the blends contained only hydrophobic ingredients, O/W type emulsions were obtained. The results indicate that all blends can stabilize O/W emulsions, but with a specific qualitative and quantitative composition. The crystal structures created by the blend components were responsible for the stabilization of all emulsions, but the most beneficial properties were provided by the blend with the addition of beeswax and sorbitan oleate. These findings provide new insights into the design of safe and ecological emulsions.
Encapsulation of Cs3Bi2Br9 perovskite photocatalyst with polythiophene for prolonged activity in oxidizing and humid environment
- Magdalena Miodyńska
- Olga Kaczmarczyk
- Wojciech Lisowski
- Andrzej Żak
- Tomasz Klimczuk
- Monika Paszkiewicz
- Adriana Zaleska-Medynska
2024 Full text APPLIED SURFACE SCIENCE
Despite their growing popularity in modern technology, halide perovskites suffer from susceptibility to oxidation, limiting their applications. Our aim was to enhance Cs3Bi2Br9 perovskite's performance in humid environments through polythiophene encapsulation. This extended its lifespan while preserving photocatalytic abilities, as demonstrated in toluene decomposition experiments. We confirmed the stability of Cs3Bi2Br9 encapsulated with polythiophene over four photocatalytic cycles and identified photogenerated electrons and superoxide radicals as key contributors to toluene decomposition. Benzaldehyde was detected as the primary toluene decomposition product, and we observed partial pollutant mineralization, evidenced by increased CO2 concentration after photocatalysis. Additionally, using hybrid ex–situ transmission electron microscopy, we observed delayed oxidation of encapsulated perovskite. Encapsulation hindered, but did not entirely prevent, water vapor penetration into Cs3Bi2Br9 particles. This progress suggests promising prospects for perovskite–based composites retaining photocatalytic capabilities under elevated humidity conditions.
Energy Constrained Depth First Search
- Shantanu Das
- Dariusz Dereniowski
- Przemysław Uznański
2024 ALGORITHMICA
Depth first search is a natural algorithmic technique for constructing a closed route that visits all vertices of a graph. The length of such a route equals, in an edge-weighted tree, twice the total weight of all edges of the tree and this is asymptotically optimal over all exploration strategies. This paper considers a variant of such search strategies where the length of each route is bounded by a positive integer $B$ (e.g. due to limited energy resources of the searcher). The objective is to cover all the edges of a tree $T$ using the minimum number of routes, each starting and ending at the root and each being of length at most $B$. To this end, we analyze the following natural greedy tree traversal process that is based on decomposing a depth first search traversal into a sequence of limited length routes. Given any arbitrary depth first search traversal $R$ of the tree $T$, we cover $R$ with routes $R_1,\ldots,R_l$, each of length at most $B$ such that: $R_i$ starts at the root, reaches directly the farthest point of $R$ visited by $R_{i-1}$, then $R_i$ continues along the path $R$ as far as possible, and finally $R_i$ returns to the root. We call the above algorithm \emph{piecemeal-DFS} and we prove that it achieves the asymptotically minimal number of routes $l$, regardless of the choice of $R$. Our analysis also shows that the total length of the traversal (and thus the traversal time) of piecemeal-DFS is asymptotically minimum over all energy-constrained exploration strategies. The fact that $R$ can be chosen arbitrarily means that the exploration strategy can be constructed in an online fashion when the input tree $T$ is not known in advance. Each route $R_i$ can be constructed without any knowledge of the yet unvisited part of $T$. Surprisingly, our results show that depth first search is efficient for energy constrained exploration of trees, even though it is known that the same does not hold for energy constrained exploration of arbitrary graphs.
Energy-Efficient Self-Supervised Technique to Identify Abnormal User Over 5G Network for E-Commerce
- Arsalan Muhammad Soomar
2024 IEEE TRANSACTIONS ON CONSUMER ELECTRONICS
Within the realm of e-commerce networks, it is frequently observed that certain users exhibit behavior patterns that differ substantially from the normative behaviors exhibited by the majority of users. The identification of these atypical individuals and the understanding of their behavioral patterns are of significant practical significance in maintaining order on e-commerce platforms. One such method for accomplishing this objective entails examining the behavioral tendencies of atypical users through the abstraction of e-commerce networks as heterogeneous information networks. These networks are then transformed into a bipartite graph that establishes associations between users and devices. The Self-Supervised Aberrant Detection Model (SAD) has been proposed within this theoretical framework as a means to identify and detect users who exhibit aberrant behavior. The SSADM methodology utilizes a self-supervised learning process that utilizes autoencoders to encode representations of user nodes. The proposed method aims to maximize a combined objective function for backpropagation while utilizing support vector data description to detect abnormalities in the representations of user nodes. In summary, many tests have been conducted utilizing both authentic network datasets and partially synthetic network datasets to demonstrate the efficacy and superiority of the SAD technique, specifically within the domain of an energy-efficient 5G network.
Engineering and Management of Space Systems - an International Joint Master's Double-Degree Programme
- Jasminka Matevska
- Marek Chodnicki
- Zbigniew Łubniewski
2024
Dynamic development of the European space sector results in a necessity for suitable Higher Education Institution graduates. Current study programs of Aerospace Technology are focused on the field of mechanical engineering. Although engineering methods for design, construction and assembly of mechanical systems are covered, interdisciplinarity and life cycle aspects are not considered in a sufficient degree. Due to the increasing digitalization, interconnection and distribution of technical systems, there is a high necessity to consider the systems with their interdisciplinarity during the entire life cycle from the initial idea through conception, design, production, integration, verification and validation to operation, maintenance and disposal in such a way that it best meets the expectations of the stakeholders and successfully accomplishes the planned mission. Current systems require different competencies depending on the characteristics of the application domain. The increasingly dynamic market requires an adaptation of traditional approaches and the introduction of agile methods in order to meet the requirements for greater flexibility and creativity. This, supplemented by management and social competencies, forms a future-oriented basis for mastering the ever-growing complexity of technical software-intensive systems. Our international interdisciplinary joint Master's double-degree program - Engineering and Management of Space Systems established as a cooperation of Bremen City University of Applied Sciences, Germany and Gdańsk University of Technology, Poland addresses all the above-mentioned systems engineering aspects and imparts competencies necessary to comprehend complex space missions as a "system of systems" during their entire life cycle. It is conducted in cooperation with the local space industry, in particular OHB, Airbus Defence and Space, and Ariane Group.
Engineering education for smart grid systems in the quasi-industrial environment of the LINTE^2 laboratory
- Andrzej Augusiak
- Filip Kutt
- Piotr Musznicki
- Janusz Nieznański
2024 Global Journal of Engineering Education
Smart grid systems are revolutionising the electric power sector, integrating advanced technologies to enhance efficiency, reliability and sustainability. It is important for higher education to equip the prospective smart grid professional with the competencies enabling them to navigate through the related complexities and drive innovation. To achieve this, interdisciplinary education programmes are necessary, addressing inter alia integration of renewable energy sources, data analytics, AI and machine learning, cybersecurity, policies and regulatory frameworks. Hands-on experience, industrial training and research-based learning are also highly desirable components of such programmes. This article describes how Gdańsk University of Technology (Gdańsk Tech), Gdańsk, Poland, employs its unique Laboratory for Innovative Power Systems and Integration of Renewable Energy Sources (LINTE^2 Lab), to support comprehensive education in smart grids. Starting with simulation and virtualisation, students gradually extend their knowledge and competencies through project, research and challenge-based activities in the quasi-industrial environment of the LINTE^2 Lab.
English Language Learning Employing Developments in Multimedia IS
- Piotr Odya
- Adam Kurowski
- Andrzej Czyżewski
2024 Full text
In the realm of the development of information systems related to education, integrating multimedia technologies offers novel ways to enhance foreign language learning. This study investigates audio-video processing methods that leverage real-time speech rate adjustment and dynamic captioning to support English language acquisition. Through a mixed-methods analysis involving participants from a language school, we explore the impact of auditory, visual, and bimodal input enhancements on learning outcomes. Results reveal that visual enhancements, especially caption highlighting, significantly enhance vocabulary acquisition and pronunciation, whereas simultaneous auditory-visual modifications show less advantage. Overall findings suggest that multimedia-enhanced environments, particularly those emphasizing visual input, can substantially improve language learning efficiency. This research contributes to Information Systems (IS) development education by proposing practical tools and strategies for embedding multimedia content in e-learning, thereby addressing the diverse needs of students in the digital era.
Enhanced acceptor concentration, proton conductivity, and hydration in multicomponent rare‐earth ortho‐niobates
- Arkadiusz Dawczak
- Wojciech Skubida
- Aleksandra Mielewczyk-Gryń
- Maria Gazda
2024 JOURNAL OF THE AMERICAN CERAMIC SOCIETY
The structural properties of (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)1−xCaxNbO4−δ (x = 0–0.05) series have been studied by X-ray powder diffraction at room temperature. The thermal properties were investigated using thermogravimetry, from which the concentration of proton defects was determined. Additionally, dilatometry studies were carried out, from which the thermal expansion coefficients and the phase transition temperature between low- and high-temperature polymorphs were determined. In order to determine the electrical properties, the electrochemical impedance spectroscopy measurements under atmospheres of dry synthetic air and saturated with water vapor and heavy water at 300–800°C temperature range were performed. All the studied materials were single-phase compositions and were stable in monoclinic I2/c crystal structure at room temperature. The water uptake studies revealed a small mass change under the switch from dry to humidified synthetic air atmospheres, suggesting the formation of proton defects. The phase transition from monoclinic to tetragonal crystal structure in the (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)1−xCaxNbO4−δ (x = 0–0.05) series occurs above 650°C. A small amount of calcium dopant increases the total conductivity in all tested atmospheres by two orders of magnitude, for example, from 0.34 μS cm−1 in La0.2Nd0.2Sm0.2Gd0.2Eu0.2NbO4 to 63.7 μS cm−1 in (La0.2Nd0.2Sm0.2Gd0.2Eu0.2)0.95Ca0.05NbO4−δ at 700°C in humid synthetic air atmosphere.
Enhanced cellulose extraction from agave plant (Agave americana Species) for synthesis of magnetic/cellulose nanocomposite for defluoridation of water
- Samuel Latebo Majamo
- Temesgen Amibo
- Ermias Tsegaw
2024 Materials Today Communications
Research on fluoride removal from water is currently focusing on the development of innovative materials for defluoridation water. The current study extracted and used enhanced cellulose from Agave americana species to synthesize a magnetic/cellulose nanocomposite for water defluoridation. Strong and light binary acids (H2SO4 and CH3COOH) were utilized to pretreat raw material to enhance cellulose extraction. Central composite design (CCD) was used to design experiments to find optimum condition for cellulose extraction. Four key factors (H2SO4 to CH3COOH ratio, acid concentration, temperature, and contact time) with three levels were designed by CCD. The lignin, hemicellulose and cellulose content of raw agave cellulosic fiber in this study were 5.5 ± 0.27, 20.5 ± 0.23 and 60.4 ± 0.31 % respectively. While, at the optimum conditions of 2.3 % acid concentration, 0.44 H2SO4 to CH3COOH ratio, 83.2 min of retention time, and 105.5 oC, cellulose content reached 940.25 %. Then, enhanced cellulose was covered with magnetic components, resulting in a magnetic/cellulose nano- composite. The adsorbent materials were characterized by Fourier Transform Infrared (FTIR) spectroscopy, X- Ray Diffractometer (XRD), Scanning electron microscopy (SEM), and Dynamic light scattering (DLS). In addition, textural features of the adsorbent were investigated. All characterization results suggest that the synthesized adsorbent has the required properties. Adsorption tests were carried out using various interaction components. The combined effects of critical process variables on defluoridation were examined. The adsorption isotherm was calculated. Overall, the research demonstrated that the produced magnetic/cellulose nanocomposite can be employed as an efficient and ecologically acceptable adsorbent for fluoride removal from water.
Enhanced electrochemical activity of boron-doped nanocarbon functionalized reticulated vitreous carbon structures for water treatment applications
- Iwona Kaczmarzyk
- Mariusz Banasiak
- Paweł Jakóbczyk
- Michał Sobaszek
- Gabriel Strugała
- Tomasz Seramak
- Paweł Rostkowski
- Jakub Karczewski
- Mirosław Sawczak
- Jacek Ryl
- Robert Bogdanowicz
2024 Full text DIAMOND AND RELATED MATERIALS
An extraordinary charge transfer kinetics and chemical stability make a boron-doped diamond (BDD) a prom- ising material for electrochemical applications including wastewater treatment. Yet, with flat geometrical sur- faces its scaling options are limited. In this study, the reticulated Vitreous Carbon (RVC) served as a substrate for boron-doped diamondized nanocarbons (BDNC) film growth resulting with complex heterogeneity carbon structures with different morphologies defined by using electron microscopy, microtomography, activation en- ergy studies, and Raman spectroscopy. The proposed modification significantly boosted the electrochemical Fe(CN)6 3 /4 redox activity. The vol- tammetry and impedimetric studies revealed its origin as a significantly higher share of electrochemically active sites at the BDNC@RVC electrode (increased by 114 %) combined with enhanced heterogeneous rate constant (2× increase up to 8.24⋅10 4 cm s 1). Finally, to establish its applicability for water treatment, the BDNC@RVC was studied as the anode in electrochemical paracetamol decomposition. Boron-enriched nanoarchitecture formed at the RVC electrode surface substantially reduced the oxidation energy barrier manifested as a decrease in activation overpotential by 212 mV, which gave a consequence in a 78 % removal rate (in 4 h, at 0.7 mA cm 2), 12 % higher than bare RVC and yielding lower amounts of APAP decomposition intermediates.
Enhanced Electrochemical Performance of MnCo1.5Fe0.5O4Spinel for Oxygen Evolution Reaction through Heat Treatment
- Krystian Lankauf
- Bartłomiej Lemieszek
- Karolina Górnicka
- Patryk Błaszczak
- Marcin Zając
- Piotr Jasiński
- Sebastian Molin
2024 Full text ENERGY & FUELS
MnCo1.5Fe0.5O4 spinel oxide was synthesized using the sol−gel technique, followed by heat treatment at various temperatures (400, 600, 800, and 1000 °C). The prepared materials were examined as anode electrocatalysts for watersplitting systems in alkaline environments. Solid-state characterization methods, such as powder X-ray diffraction and X-ray absorption spectroscopy (XAS), were used to analyze the materials’ crystallographic structure and surface characteristics. The intrinsic activity of the MnCo1.5Fe0.5O4 was fine-tuned by altering the electronic structure by controlling the calcination temperature, and the highest activity was observed for the sample treated at 800 °C. A shift in the valence state of surface cations under oxidative conditions in an alkaline solution during the oxygen evolution reaction was detected through ex situ XAS measurements. Moreover, the influence of the experimental conditions on the electrocatalytic performance of the material, including the pH of the electrolyte and the temperature, was demonstrated.
Enhanced electrochemical performance of partially amorphous La0.6Sr0.4CoO3-δ oxygen electrode materials for low-temperature solid oxide cells operating at 400 °C
- Bartłomiej Lemieszek
- Mindaugas Ilickas
- Jan Jamroz
- Asta Tamulevičienė
- Jakub Karczewski
- Patryk Błaszczak
- Alexey Maximenko
- Brigita Abakevičiene
- Marcin Małys
- Sigitas Tamulevičius
- Piotr Jasiński
- Sebastian Molin
2024 Full text APPLIED SURFACE SCIENCE
This work evaluates partially amorphous La0.6Sr0.4CoO3-δ (LSC) as a potential oxygen electrode for lowtemperature solid oxide cells. LSC was deposited using the spin-coating technique onto Ce0.8Gd0.2O2-δ (CGO) substrates. The optimal oxygen electrode thickness was determined as 500 nm. The electrochemical impedance spectroscopy (EIS) study showed a significant improvement in oxygen reduction/oxidation reaction kinetics when annealing temperatures below 600 ◦C. The lowest value of the polarisation resistance was observed for the sample annealed at 400 ◦C, followed by a temperature of 500 ◦C. EIS measurements at different pO2 content were performed at levels between 0.5 % and 20 %. A comprehensive equivalent circuit analysis was carried out for an explanation of the limiting factors of the catalytic reaction. X-ray absorption fine structure analysis allowed for the identification of differences between crystalline LSC and its partially amorphous form. X-ray absorption nearedge spectroscopy analysis indicated that cobalt adopts a lower oxidation state for the partially amorphous form. Moreover, extended X-ray absorption fine structure analysis indicated the decreased of cobalt oxidation state in partially amorphous LSC. It can be assumed that the increased activity of LSC at temperatures below the crystallization may be due to increased defects and oxygen vacancies in the material.
Enhanced Mechanical and Electromechanical Properties of Compositionally Complex Zirconia Zr1–x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2−δ Ceramics
- Ahsanul Kabir
- Bartłomiej Lemieszek
- Maxim Varenik
- Victor Buratto Tinti
- Sebastian Molin
- Igor Lubomirsky
- Vincenzo Esposito
- Frank Kern
2024 ACS Applied Materials & Interfaces
Compositionally complex oxides (CCOs) or high-entropy oxides (HEOs) are new multi-element oxides with unexplored physical and functional properties. In this work, we report fluorite structure derived compositionally complex zirconia with composition Zr1- x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2-δ (x = 0.1 and 0.2) synthesized in solid-state reaction route and sintered via hot pressing at 1350 °C. We explore the evolution of these oxides' structural, microstructural, mechanical, electrical, and electromechanical properties regarding phase separation and sintering mechanisms. Highly dense ceramics are achieved by bimodal mass diffusion, composing nanometric tetragonal and micrometric cubic grains microstructure. The material exhibits an anomalously large electrostriction response exceeding the M33 value of 10−17 m 2 /V2 at room temperatures and viscoelastic properties of primary creep in nanoindentation measurement under fast loading. These findings are strikingly similar to those reported for doped ceria and bismuth oxide derivates, highlighting the presence of a large concentration of point defects linked to structural distortion and anelastic behavior are characteristics of nonclassical ionic electrostrictors.
Enhanced Spectroscopic Insight into Acceptor-Modified Barium Strontium Titanate Thin Films Deposited via the Sol–Gel Method
- Dionizy Czekaj
- Agata Lisińska-Czekaj
2024 Full text Materials
In the present paper, composite thin films of barium strontium titanate (BaxSr1−xTiO3) with an acceptor modifier (magnesium oxide—MgO) were deposited on metal substrates (stainless steel type) using the sol–gel method. The composite thin films feature BaxSr1−xTiO3 ferroelectric solid solution as the matrix and MgO linear dielectric as the reinforcement, with MgO concentrations ranging from 1 to 5 mol%. Following thermal treatment at 650 °C, the films were analyzed for their impedance response. Experimental impedance spectra were modeled using the Kohlrausch–Williams–Watts function, revealing stretching parameters (β) in the range of approximately 0.78 to 0.89 and 0.56 to 0.90 for impedance and electric modulus formalisms, respectively. Notably, films modified with 3 mol% MgO exhibited the least stretched relaxation function. Employing the electric equivalent circuit method for data analysis, the “circle fit” analysis demonstrated an increase in capacitance from 2.97 × 10−12 F to 5.78 × 10−10 F with the incorporation of 3 mol% MgO into BST-based thin films. Further analysis based on Voigt, Maxwell, and ladder circuits revealed trends in resistance and capacitance components with varying MgO contents, suggesting non-Debye-type relaxation phenomena across all tested samples.
Enhanced visible light-activated gas sensing properties of nanoporous copper oxide thin films
- Andrzej Kwiatkowski
- Janusz Smulko
- Katarzyna Drozdowska
2024 Full text SOLAR ENERGY MATERIALS AND SOLAR CELLS
Metal oxide gas sensors are popular chemoresistive sensors. They are used for numerous tasks, including environmental and safety monitoring. Some gas-sensing materials exhibit photo-induced properties that can be utilized for enhanced gas detection by modifying the sensor selectivity and sensitivity when illuminated by light. Here, we present the gas sensing characteristics of highly nanoporous Cu2O thin films towards both electrophilic (NO2) and nucleophilic (C2H5OH, NH3) gas molecules under ambient temperature and modulated by visible light illumination of different colors (red: 632 nm, green: 530 nm, blue: 468 nm). Cu2O films were fabricated by reactive advanced gas deposition (AGD) technology. The surface and structural analysis of the samples confirm the deposition of nanoporous thin films of mixed copper oxide phases. The gas sensing property of Cu2O exhibited expected p-type semiconductor behavior upon electrophilic and nucleophilic gas exposures. Our results show that visible light illumination provides enhanced sensor response.
Enhancing Business Process Management Through Nature Assessment: Development and Deployment of the Business Process Nature Assessment Tool
- Marzena Grzesiak
- Marek Szelągowski
- Marek Moszyński
- Justyna Berniak-Woźny
2024
In contemporary business landscapes, the diverse nature of processes necessitates a thor-ough assessment before implementing Business Process Management (BPM). However, conducting such assessments can be arduous, particularly for small and medium-sized en-terprises. This study aims to address this challenge by developing and showcasing the utility of an online tool based on the Business Process Nature Assessment Framework (BPNAF). The BPNAF facilitates integrated assessments of business processes, aligning with estab-lished BPM methodologies and lifecycles. Through an illustrative case study, this research examines the efficacy of this tool in assessing the processes / nature. The BPNA tool ena-bles swift and effective evaluations of process unpredictability and knowledge intensity, aiding in selecting appropriate BPM methodologies, Knowledge Management (KM) and Human Resource Management (HRM) strategies, and supporting IT systems. Visualised results offer clear recommendations tailored to the organisation's unique process landscape, accommodating standard and customised recommendations. By contributing insights into practical BPNAF implementation, this study plays a pivotal role in advancing BPM assess-ment methodologies and enriching the understanding and practice of BP management. This research underscores the critical role of BP assessment in organisational success, advocating for informed decision-making and best practices in BPM.
Enhancing chain-elongating microbiomes: Sequential fungi-bacteria cooperation for efficient food waste upgrading using endogenous electron donors
- Xiang Li
- Xiaolin Lei
- Zhichao Guo
- Ziyi Yan
- Xia Gu
- Xianbao Xu
- Hussein Al-Hazmi
- Gang Xue
- Jiajie Xu
- Piotr Oleskowicz-Popiel
- Jacek Mąkinia
2024 CHEMICAL ENGINEERING JOURNAL
The upgrading of organic waste such as food waste (FW) into medium-chain carboxylates (MCC) is within a bio-based circular economy concept. An efficient chain elongation (CE) microbiome is difficult to obtain, which normally requires long-term acclimatization and an exogenous supplement of electron donor (ED, especially ethanol). In this study, the CE microbiome was rapidly shaped within 18 days and an efficient endogenous ethanol-based CE was achieved through the amendment of distiller yeast (DY) during FW fermentation. Multiple FW feeding accumulated the caproate concentration to 5.76 ± 0.33 g COD/L, which also regulated the CE process from ethanol-dependent to lactate-dependent metabolism. During the lactate-based CE process, the caproate production increased linearly (R2 = 0.82) with the rising D-lactate content. Ethanol-producing fungi yeast mainly consisted of Wickerhamomyces (66.54 %), Saccharomycopsis (5.37 %), Issatchenkia (2.21 %), unclassified_f_Metschnikowiaceae (1.73 %), and Saccharomyces (1.33 %). These yeasts were eliminated by FW feeding, which was in line with the alteration of ED preference from ethanol to lactate. Metagenome analysis indicated that the total relative abundance of lactate-based chain elongators including Ruminococcaceae bacterium CPB6, Clostridium luticellarii, Caproiciproducens galactitolivorans, and Megasphaera elsdenii was increased by 28.6 %, while the ethanol-based chain elongator Clostridium kluyveri kept stable after FW feeding. In addition, the functional genes related to the oxidation of lactate to acetyl-CoA were enriched after FW feeding, which further enhanced the subsequent CE pathway of acetyl-CoA-based reverse β oxidation rather than the fatty acids synthesis. This study provides a new insight into upgrading FW into valuable MCC without exogenous ED addition.
Enhancing colloidal stability of nanodiamond via surface modification with dendritic molecules for optical sensing in physiological environments
- Maciej Głowacki
- Paweł Niedziałkowski
- Jacek Ryl
- Marta Prześniak-Welenc
- Mirosław Sawczak
- Klaudia Prusik
- Mateusz Ficek
- Monika Janik
- Krzysztof Pyrchla
- Michał Olewniczak
- Krzysztof Bojarski
- Jacek Czub
- Robert Bogdanowicz
2024 Full text JOURNAL OF COLLOID AND INTERFACE SCIENCE
Pre-treatment of diamond surface in low-temperature plasma for oxygenation and in acids for carboxylation was hypothesized to promote the branching density of the hyperbranched glycidol polymer. This was expected to increase the homogeneity of the branching level and suppress interactions with proteins. As a result, composite nanodiamonds with reduced hydrodynamic diameters that are maintained in physiological environments were anticipated. Surfaces of 140-nm-sized nanodiamonds were functionalized with oxygen and carboxyl groups for grafting of hyperbranched dendritic polyglycerol via anionic ring-opening polymerization of glycidol. The modification was verified with Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Dynamic light scattering investigated colloidal stability in pH-diverse (2–12) solutions, concentrated phosphate-buffered saline, and cell culture media. Thermogravimetric analysis of nanodiamonds-protein incubations examined non-specific binding. Fluorescence emission was tested across pH conditions. Molecular dynamics simulations modeled interparticle interactions in ionic solutions. The hyperbranched polyglycerol grafting increased colloidal stability of nanodiamonds across diverse pH, high ionic media like 10 × concentrated phosphate-buffered saline, and physiological media like serum and cell culture medium. The hyperbranched polyglycerol suppressed non-specific protein adsorption while maintaining intensive fluorescence of nanodiamonds regardless of pH. Molecular modelling indicated reduced interparticle interactions in ionic solutions correlating with the improved colloidal stability.
Enhancing electrical properties through in-situ controlled nanocrystallization of V2O5–TeO2 glass
- Piotr Okoczuk
- Agnieszka Kwiatkowska
- Leon Murawski
- Tomasz Pietrzak
- Natalia Wójcik
- Fabian Garmroudi
- Leszek Wicikowski
- Barbara Kościelska
2024 Full text JOURNAL OF MATERIALS SCIENCE
V2O5–TeO2 glass–ceramics (VTGC) were prepared by controlled annealing of the V2O5–TeO2 glass (VTG), which illustrates a parent glass matrix with a single charge carrier. The annealing proceeded at six temperatures selected between the glass transition and the maximum of the frst crystallization process to obtain various nanocrystallite sizes. Heat treatment caused an increase in DC conductivity by 2.5–3.5 (250–285 °C) order of magnitude. Using thermal analysis, the crystal growth process was determined to be 1D. Structural studies show that the obtained materials are partially amorphous and polycrystalline with nanometersized crystallites. Subtle thread-like structures were observed using conductive AFM. The activation energy of the conduction process decreased from 0.38 eV in VTG to 0.18–0.11 eV (250–285 °C) in VTGC. The radii of crystallites were calculated based on the theoretical model of electron hopping between connected semiconducting nanocrystallites and vary between 1.7 and 2.8 nm (250–285 °C). Thermoelectric studies indicate constant carrier concentration. Features characteristic of small polaron hopping-governed materials were observed. We suggest V3O7 nanocrystals as conductive media in VTGC.