bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipid-Based Catalysis Demonstrated by Bilayer-Enabled Ester Hydrolysis
Authors: Liu Shu , Kumar Kiran , Bell Tracey , Ramamoorthy Ayyalusamy , Van Winkle David , Lenhert Steven
Published: July 2024

Lipids have not traditionally been considered likely candidates for catalyzing reactions in biological systems. However, there is significant evidence that aggregates of amphiphilic compounds are capable of catalyzing reactions in synthetic organic chemistry. Here, we demonstrate the potential for the hydrophobic region of a lipid bilayer to provide an environment suitable for catalysis by means of a lipid aggregate capable of speeding up a chemical reaction. By bringing organic molecules into the nonpolar or hydrophobic region of a lipid bilayer, reactions can be catalyzed by individual or collections of small, nonpolar, or amphiphilic molecules. We demonstrate this concept by the ester hydrolysis of calcein-AM to produce a fluorescent product, which is a widely used assay for esterase activity in cells. The reaction was first carried out in a two-phase octanol–water system, with the organic phase containing the cationic amphiphiles cetyltrimethylammonium bromide (CTAB) or octadecylamine. The octanol phase was then replaced with phospholipid vesicles in water, where the reaction was also found to be carried out. The reaction was monitored using quantitative fluorescence, which revealed catalytic turnover numbers on a scale of 10−7 to 10−8 s−1 for each system, which is much slower than enzymatic catalysis. The reaction product was characterized by 1H-NMR measurements, which were consistent with ester hydrolysis. The implications of thinking about lipids and lipid aggregates as catalytic entities are discussed in the context of biochemistry, pharmacology, and synthetic biology.
Unlocking the Potential: Caloric Restriction, Caloric Restriction Mimetics, and Their Impact on Cancer Prevention and Treatment
Authors: De-Leon-Covarrubias Ulises Edgardo , Perez-Trujillo Jose Juan , Villa-Cedillo Sheila Adela , Martinez-Perez Alejandra Guadalupe , Montes-de-Oca-Saucedo Carlos Roberto , Loera-Arias Maria de Jesus , Garcia-Garcia Aracely , Saucedo-Cardenas Odila , Montes-de-Oca-Luna Roberto
Published: July 2024

Caloric restriction (CR) and its related alternatives have been shown to be the only interventions capable of extending lifespan and decreasing the risk of cancer, along with a reduction in burden in pre-clinical trials. Nevertheless, the results from clinical trials have not been as conclusive as the pre-clinical results. Recognizing the challenges associated with long-term fasting, the application of caloric restriction mimetics (CRMs), pharmacological agents that mimic the molecular effects of CR, to harness the potential benefits while overcoming the practical limitations of fasting has resulted in an interesting alternative. This review synthesizes the findings of diverse clinical trials evaluating the safety and efficacy of CR and CRMs. In dietary interventions, a fast-mimicking diet was the most tolerated to reduce tumoral growth markers and chemotherapy side effects. CRMs were well tolerated, and metformin and aspirin showed the most promising effect in reducing cancer risk in a selected group of patients. The application of CR and/or CRMs shows promising effects in anti-cancer therapy; however, there is a need for more evidence to safely include these interventions in standard-of-care therapies.
Lysine Phoshoglycerylation Is Widespread in Bacteria and Overlaps with Acylation
Authors: Mikkat Stefan , Kreutzer Michael , Patenge Nadja
Published: July 2024

Phosphoglycerylation is a non-enzymatic protein modification in which a phosphoglyceryl moiety is covalently bound to the ε-amino group of lysine. It is enriched in glycolytic enzymes from humans and mice and is thought to provide a feedback mechanism for regulating glycolytic flux. We report the first proteomic analysis of this post-translational modification in bacteria by profiling phosphoglyceryl-lysine during the growth of Streptococcus pyogenes in different culture media. The identity of phosphoglyceryl-lysine was confirmed by a previously unknown diagnostic cyclic immonium ion generated during MS/MS. We identified 370 lysine phosphoglycerylation sites in 123 proteins of S. pyogenes. Growth in a defined medium on 1% fructose caused a significant accumulation of phosphoglycerylation compared to growth in a rich medium containing 0.2% glucose. Re-analysis of phosphoproteomes from 14 bacterial species revealed that phosphoglycerylation is generally widespread in bacteria. Many phosphoglycerylation sites were conserved in several bacteria, including S. pyogenes. There was considerable overlap between phosphoglycerylation, acetylation, succinylation, and other acylations on the same lysine residues. Despite some exceptions, most lysine phosphoglycerylations in S. pyogenes occurred with low stoichiometry. Such modifications may be meaningless, but it is also conceivable that phosphoglycerylation, acetylation, and other acylations jointly contribute to the overall regulation of metabolism.
Bacterial Communities across Multiple Ecological Niches (Water, Sediment, Plastic, and Snail Gut) in Mangrove Habitats
Authors: Al-Tarshi Muna , Dobretsov Sergey , Al-Belushi Mohammed
Published: July 2024

Microbial composition across substrates in mangroves, particularly in the Middle East, remains unclear. This study characterized bacterial communities in sediment, water, Terebralia palustris snail guts, and plastic associated with Avicennia marina mangrove forests in two coastal lagoons in the Sea of Oman using 16S rDNA gene MiSeq sequencing. The genus Vibrio dominated all substrates except water. In the gut of snails, Vibrio is composed of 80–99% of all bacterial genera. The water samples showed a different pattern, with the genus Sunxiuqinia being dominant in both Sawadi (50.80%) and Qurum (49.29%) lagoons. There were significant differences in bacterial communities on different substrata, in particular plastic. Snail guts harbored the highest number of unique Operational Taxonomic Units (OTUs) in both lagoons, accounting for 30.97% OTUs in Sawadi and 28.91% OTUs in Qurum, compared to other substrates. Plastic in the polluted Sawadi lagoon with low salinity harbored distinct genera such as Vibrio, Aestuariibacter, Zunongwangia, and Jeotgalibacillus, which were absent in the Qurum lagoon with higher salinity and lower pollution. Sawadi lagoon exhibited higher species diversity in sediment and plastic substrates, while Qurum lagoon demonstrated lower species diversity. The principal component analysis (PCA) indicates that environmental factors such as salinity, pH, and nutrient levels significantly influence bacterial community composition across substrates. Variations in organic matter and potential anthropogenic influences, particularly from plastics, further shape bacterial communities. This study highlights the complex microbial communities in mangrove ecosystems, emphasizing the importance of considering multiple substrates in mangrove microbial ecology studies. The understanding of microbial dynamics and anthropogenic impacts is crucial for shaping effective conservation and management strategies in mangrove ecosystems, particularly in the face of environmental changes.
Tellurium Enrichment in Copper Tailings: A Mineralogical and Processing Study
Authors: Corchado-Albelo José L. , Alagha Lana
Published: July 2024

As the global demand for tellurium (Te) increases, it is crucial to develop efficient recovery methods that consider existing supply streams. This research combines gravity separation and froth flotation processes to enhance the recovery of Te minerals from tailings produced during the beneficiation of copper porphyry ores. Prior to processing, a systematic and comprehensive characterization study of copper tailing (CT) samples was conducted to examine the deportment of Te minerals in different mineral phases and to understand their locking and liberation behavior. Characterization techniques included inductively coupled plasma mass spectrometry (ICP-MS) and TESCAN’s integrated mineral analysis (TIMA). Copper tailing characterization showed that minerals with gold (Au), silver (Ag), bismuth (Bi), and Te were present in various forms, including native Au, electrum, tellurides, and sulfosalts. TIMA revealed that >90% of these minerals were primarily hosted in pyrite as less than 10 µm inclusions in the CT. TIMA also revealed that Te minerals exhibited fine-grained liberation of less than 20 μm. Moreover, TIMA results showed that >80% of mica and other silicate minerals were concentrated in size fractions < 38 μm, suggesting that desliming processes would positively impact Te enrichment. The results from the processing tests showed a Te recovery rate of ~77% and a Te enrichment ratio of 13 when using the combination of gravity separation and froth flotation at 90 g/t xanthate collector and 50 g/t glycol frother. The findings from this study show a significant potential for Te recovery from unconventional sources if appropriate physical beneficiation approaches are adopted.
Influence of Carbonated Pyrolysis Oil Recycled from Scrap Tires on Metallurgical Efficiency of Coal Flotation
Authors: Hasanizadeh Iman , Khoshdast Hamid , Safari Mehdi , Asgari Kaveh , Rahmanian Ahmad
Published: July 2024

This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms.
Diagenesis of Cenomanian–Early Turonian and the Control of Carbonate Reservoirs in the Northern Central Arabian Basin
Authors: Li Fengfeng , Li Yong , Han Haiying , Zhang Wenqi , Li Lei
Published: July 2024

The carbonate reservoirs of Cenomanian–Early Turonian in the northeastern Central Arabian Basin hold considerable oil reserves and are great contributors to oil production. Diagenesis have a great impact on carbonate reservoir petrophysical properties, microstructure, and heterogeneity. By integrating cores, cast thin sections, regular core analysis, CT, and isotopes, this study provides an improved understanding of diagenesis in the Cenomanian–Early Turonian and its effect on carbonate reservoirs. The results showed that three diagenetic environments were identified in the Cenomanian–Early Turonian based on texture, structure, cement, crystal form, and crystal size, which were marine environment, meteoric environment, and burial environment. Six diageneses were identified based on residual bioclastic, secondary pores, calcite quantity, dolomite size, and stylolite, namely dissolution, cementation, micritization, dolomitization, compaction, and pressure solution. A micritization model in high energy sediment, a dolomitization model in burrows, and a comprehensive diagenetic model were established. It concluded that dissolution during meteoric environment is most favorable to reservoir physical properties, while cementation is least favorable. The cement content controls the microstructure and petrophysical property. Micritization is detrimental to the petrophysical properties, and the micrite it forms are distributed in the interparticle pores, reducing the reservoir property deposited in high energy environment. Dolomitization is less developed in substrate but widely developed in burrows, which result in the physical properties of the burrows being higher than those of substrate. Compaction and pressure solution have a negative impact on reservoir physical properties.
The Main Controlling Factors of the Cambrian Ultra-Deep Dolomite Reservoir in the Tarim Basin
Authors: Zhang Kehui , You Xuelian , Ma Tianyi , Wang Jia , Wu Yifen , Lu Yi , Zhang Shaoqi
Published: July 2024

The genesis of deep-to-ultra-deep dolomite reservoirs in the Tarim Basin is crucial for exploration and development. The Cambrian subsalt dolomite reservoirs in the Tarim Basin are widely distributed, marking significant prospects for ultra-deep reservoir exploration. Based on big data methodologies, this study collects and analyzes porosity and permeability data of carbonate reservoirs in the western Tarim Basin, specifically targeting the Cambrian deep-oil and gas-reservoir research. Through an examination of the sedimentary evolution and distribution of carbonate–evaporite sequences, and considering sedimentary facies, stratigraphic sediment thickness, fault zone distribution, and source-reservoir assemblages as primary reference factors, the study explores the macro-distribution patterns of porosity and permeability, categorizing three favorable reservoir zones. The controlling factors for the development of Cambrian carbonate reservoirs on the western part of the Tarim Basin are analyzed from the perspectives of sedimentary and diagenetic periods. Factors such as tectonic activity, depositional environment, microbial activity, and pressure dissolution are analyzed to understand the main causes of differences in porosity and permeability distribution. Comprehensive analysis reveals that the porosity and permeability of the Series2 carbonate reservoirs are notably high, with extensive distribution areas, particularly in the Bachu–Tazhong and Keping regions. The geological pattern of “Three Paleo-uplifts and Two Depressions” facilitated the formation of inner-ramp and intra-platform shoals, creating conducive conditions for the emergence of high-porosity reservoirs. The characteristics of reservoir development are predominantly influenced by diagenetic and tectonic activities. The Miaolingian is chiefly affected by diagenesis, featuring high permeability but lower porosity and smaller distribution range; dolomitization, dissolution, and filling processes under a dry and hot paleoclimate significantly contribute to the formation and preservation of reservoir spaces. In the Furongian, the Keping and Bachu areas display elevated porosity and permeability levels, along with substantial sedimentary thickness. The conservation and development of porosity within thick dolomite sequences are mainly governed by high-energy-particulate shallow-shoal sedimentary facies and various dissolution actions during diagenesis, potentially indicating larger reserves.
Study of the Geological Context of the 7th–6th Century BC Phoenician Era Shipwreck “Mazarrón 2” (Murcia, Spain)
Authors: Doménech-Carbó María-Teresa , Guasch-Ferré Nuria , Álvarez-Romero Carla , Castillo-Belinchón Rocío , Pérez-Mateo Soledad , Buendía-Ortuño Milagros
Published: July 2024

The Mazarrón 2 shipwreck was found in 1994 on the beach of Playa de la Isla (Mazarrón, Murcia, Spain). This finding is extremely important because the boat and its lead cargo were still in a reasonable conservation state and, therefore, provided new data on naval construction, commercial goods, navigation routes, and the relationships between the Phoenicians and the local population in the 7th–6th century BC. Currently, the shipwreck remains underwater, protected by a metallic coffer. In the last 2 years, a Preliminary Studies Project has been carried out, supported by national and regional public institutions. This research aims to know the shipwreck’s conservation state and to determine the extraction and conservation methods at the Museo Nacional de Arqueología Subacuática ARQVA (Cartagena, Spain), where the conservation and restoration treatment will be conducted. The sampling strategy and analytical study included not only wood and other materials from the shipwreck and its cargo but also the seawater and the seabed materials in the vicinity of the shipwreck. This paper presents the results of the geochemical study of the archeological site. The applied methodology included physico-chemical tests, X-ray diffraction, optical microscopy, FTIR spectroscopy, field-emission scanning electron microscopy coupled with X-ray microanalysis, and X-ray microscopy. The results indicated that, despite the wreck being buried at a shallow depth (less than 50 cm) in a marine environment with a water column of 2–2.5 m, influenced by complex coastal dynamics that favor an oxic environment, early diagenetic processes like the formation of pyrite framboids are particularly intense in the pores and internal channels of the wreck’s wood, where a different dysoxic–anoxic environment prevails. These processes have been the main mechanisms to have affected the wreck and are related to the biogeochemistry of sediments. The sediments have been confirmed to be closely related to the geological context of the Mazarrón region. The conducted study found no significant evidence of pollution due to the lead cargo.
Preparation of Oxidized Pellets from Sulfuric Acid Residue Containing Zinc and Lead by Chlorination Roasting and Its Mechanism of Dezincing and Lead Removal
Authors: Liu Wei , Pan Jian , Yang Congcong , Zhu Deqing , Guo Zhengqi , Li Siwei
Published: July 2024

The utilization of sulfur acid residue is an urgent problem confronting sulfuric acid production enterprises, especially the application of sulfur acid residue (SAR) containing lead and zinc. A method combining chlorination roasting using CaCl2 with pelletizing for processing SAR containing lead and zinc was used in this study, and the effect of calcium chloride on pelletizing performance was studied; in addition, the removal behavior of lead and zinc was also studied by using polarized light microscopy (Zeiss double Axioskop 40A), X ray diffraction, SEM and EDS. The results showed that CaCl2 migrated to the surface of the pellets during drying, and this phenomenon resulted in a lower removal rate of lead and zinc inside the pellets than outside the pellets during the preheating phase. When the roasting temperature was 1220 °C, with an increase in the basicity of pellets, the silicate minerals in the pellets gradually decomposed, the hematite particles were gradually refined, and more lead or zinc minerals were exposed, which further increased the removal rate of lead and zinc in the pellets. Finally, the SAR pellets with Pb and Zn removal rates up to 91.33 and 97.88%, and a compressive strength of 2789 N, could be obtained, which is very beneficial to the sustainable development of sulfuric acid mills.
Quantum Prism—Nano Source of Light with Dispersive Spectrum and Optical Upconversion
Authors: Medvids Arturs , Ščajev Patrik , Miasojedovas Saulius , Hara Kazuhiko
Published: July 2024

A quantum prism, a new structure, consisting of many quantum wires with a diameter that gradually decreases from the base to the top, is the focus of our research. This distribution of quantum wires leads to a dispersive emitted spectrum. The red edge of the spectrum is determined by the band gap width of the bulk semiconductor, and the blue edge is determined by the quantum size of the excitons at the top of the prism. The PL spectrum of the silicon prismatic sample was excited by weak and strong light absorption. At weak absorption (hνex = 1.2 eV), the PL spectrum is located in the visible part of the spectrum, from 1.4 eV to 1.9 eV, with an energy higher than the band gap of the Si crystal. Such a “blue shift” of PL spectra by 0.7 eV is characteristic of the quantum confinement effect. It is a rainbow spectrum with an optical upconversion. The quantum prism is a new type of nano light source, as it replaces two elements in a conventional spectrometer: a light source and a dispersive element. These features enable to create a nano-spectrometer for measuring the absorption spectrum of individual molecules or viruses.
Enhanced Fenton Degradation of Tetracycline over Cerium-Doped MIL88-A/g-C3N4: Catalytic Performance and Mechanism
Authors: Eltaweil Abdelazeem S. , Galal Amira M. , Abd El-Monaem Eman M. , Al Harby Nouf , Batouti Mervette El
Published: July 2024

Since enormous amounts of antibiotics are consumed daily by millions of patients all over the world, tons of pharmaceutical residuals reach aquatic bodies. Accordingly, our study adopted the Fenton catalytic degradation approach to conquer such detrimental pollutants. (Ce0.33Fe) MIL-88A was fabricated by the hydrothermal method; then, it was supported on the surface of g-C3N4 sheets using the post-synthetic approach to yield a heterogeneous Fenton-like (Ce0.33Fe) MIL-88A/10%g-C3N4 catalyst for degrading the tetracycline hydrochloride drug. The physicochemical characteristics of the catalyst were analyzed using FT-IR, SEM-EDX, XRD, BET, SEM, and XPS. The pH level, the H2O2 concentration, the reaction temperature, the catalyst dose, and the initial TC concentration were all examined as influencing factors of TC degradation efficiency. Approximately 92.44% of the TC was degraded within 100 min under optimal conditions: pH = 7, catalyst dosage = 0.01 g, H2O2 concentration = 100 mg/L, temperature = 25 °C, and TC concentration = 50 mg/L. It is noteworthy that the practical outcomes revealed how the Fenton-like process and adsorption work together. The degradation data were well-inspected by first-order and second-order models to define the reaction rate. The synergistic interaction between the (Ce0.33Fe) MIL-88A/10%g-C3N4 components produces a continuous redox cycle of two active metal species and the electron-rich source of g-C3N4. The quenching test demonstrates that •OH is the primary active species for degrading TC in the H2O2–(Ce0.33Fe) MIL-88A/10%g-C3N4 system. The GC-MS spectrum elucidates the yielded intermediates from degrading the TC molecules.
The Association between Body Composition Phenotype and Insulin Resistance in Post-COVID-19 Syndrome Patients without Diabetes: A Cross-Sectional, Single-Center Study
Authors: González-Islas Dulce , Flores-Cisneros Laura , Orea-Tejeda Arturo , Keirns-Davis Candace , Hernández-López Nadia , Arcos-Pacheco Laura Patricia , Zurita-Sandoval Andrea , Albarran-López Frida , García-Castañeda Luis , Salgado-Fernández Fernanda , Hernández-López Samantha , Jiménez-Valentín Angelia , Pérez-García Ilse
Published: July 2024

Background: The most frequent body composition alterations in post-COVID-19 syndrome include low muscle mass, dynapenia, sarcopenia, and obesity. These conditions share interconnected pathophysiological mechanisms that exacerbate each other. The relationship between body composition phenotypes and metabolic abnormalities in post-COVID-19 syndrome remains unclear. Objective: To evaluate the association between body composition phenotypes and insulin resistance (IR) and metabolic abnormalities in non-diabetic individuals with post-COVID-19 syndrome. Methods: A cross-sectional, single-center study involving 483 subjects with post-COVID-19 syndrome following moderate to severe acute COVID-19 requiring hospitalization. Individuals with diabetes, those who declined to participate, or those who could not be contacted were excluded. Body composition phenotypes were classified as normal weight, dynapenia, sarcopenia, dynapenic obesity, and sarcopenic obesity (SO). Results: The average age was 52.69 ± 14.75 years; of note, 67.08% were male. The prevalence of body composition phenotypes was as follows: 13.25% were of normal weight, 9.52% had dynapenia, 9.94% had sarcopenia, 43.69% had obesity, 18.84% had dynapenic obesity, and 4.76% had SO. Additionally, 58.18% had IR. Obesity (OR: 2.98, CI95%; 1.64–5.41) and dynapenic obesity (OR: 4.98, CI95%; 1.46–6.88) were associated with IR. Conclusion: The most common body composition phenotypes were obesity, dynapenic obesity, and dynapenia. Furthermore, obesity and dynapenic obesity were associated with IR in post-COVID-19 syndrome.
pH-Sensitive Fluorescent Marker Based on Rhodamine 6G Conjugate with Its FRET/PeT Pair in “Smart” Polymeric Micelles for Selective Imaging of Cancer Cells
Authors: Zlotnikov Igor D. , Ezhov Alexander A. , Kudryashova Elena V.
Published: July 2024

Cancer cells are known to create an acidic microenvironment (the Warburg effect). At the same time, fluorescent dyes can be sensitive to pH, showing a sharp increase or decrease in fluorescence depending on pH. However, modern applications, such as confocal laser scanning microscopy (CLSM), set additional requirements for such fluorescent markers to be of practical use, namely, high quantum yield, low bleaching, minimal quenching in the cell environment, and minimal overlap with auto-fluorophores. R6G could be the perfect match for these requirements, but its fluorescence is not pH-dependent. We have attempted to develop an R6G conjugate with its FRET or PeT pair that would grant it pH sensitivity in the desired range (5.5–7.5) and enable the selective targeting of tumor cells, thus improving CLSM imaging. Covalent conjugation of R6G with NBD using a spermidine (spd) linker produced a pH-sensitive FRET effect but within the pH range of 7.0–9.0. Shifting this effect to the target pH range of 5.5–7.5 appeared possible by incorporating the R6G-spd-NBD conjugate within a “smart” polymeric micelle based on chitosan grafted with lipoic acid. In our previous studies, one could conclude that the polycationic properties of chitosan could make this pH shift possible. As a result, the micellar form of the NBD-spd-R6G fluorophore demonstrates a sharp ignition of fluorescence by 40%per1 pH unit in the pH range from 7.5 to 5. Additionally, “smart” polymeric micelles based on chitosan allow the label to selectively target tumor cells. Due to the pH sensitivity of the fluorophore NBD-spd-R6G and the selective targeting of cancer cells, the efficient visualization of A875 and K562 cells was achieved. CLSM imaging showed that the dye actively penetrates cancer cells (A875 and K562), while minimal accumulation and low fluorophore emission are observed in normal cells (HEK293T). It is noteworthy that by using “smart” polymeric micelles based on polyelectrolytes of different charges and structures, we create the possibility of regulating the pH dependence of the fluorescence in the desired interval, which means that these “smart” polymeric micelles can be applied to the visualization of a variety of cell types, organelles, and other structures.
Research on a Near-Field Millimeter Wave Imaging Algorithm and System Based on Multiple-Input Multiple-Output Sparse Sampling
Authors: Zhang He , Zong Hua , Qiu Jinghui
Published: July 2024

In order to reduce the hardware cost and data acquisition time in near-field scenarios, such as airport security imaging systems, this paper discusses the layout of a multiple-input multiple-output (MIMO) radar array. In view of the existing multi-input multiple-output imaging algorithm, the reconstructed image artifacts and aliasing problems caused by sparse sampling are discussed. In this paper, a multi-station radar array and a corresponding sparse MIMO imaging algorithm based on combined sparse sub-channels are proposed. By studying the wave–number spectrum of backscattered MIMO synthetic aperture radar (SAR) data, the nonlinear relationship between the wave number spectrum and reconstructed image is established. By selecting a complex gain vector, multiple channels are coherently combined effectively, thus eliminating aliasing and artifacts in the reconstructed image. At the same time, the algorithm can be used for the MIMO–SAR configuration of arbitrarily distributed transmitting and receiving arrays. A new multi-station millimeter wave imaging system is designed by using a frequency-modulated continuous wave (FMCW) chip and sliding rail platform as a planar SAR. The combination of the hardware system provides reconfiguration, convenience and economy for the combination of millimeter wave imaging systems in multiple scenes.
5.3 W/265 μJ Mid-IR All-Fiber Er3+:ZBLAN Gain-Switched Laser Based on Dielectric Fiber Mirror and Fiber-Tip Protection
Authors: Chen Tingting , Su Jue , Zhong Wenbo , Ding Yu , Huang Lu , Bu Yikun , Li Jianfeng , Luo Zhengqian
Published: July 2024

We report a 2.8 μm all-fiber high-power and high-energy gain-switched Er3+:ZBLAN laser based on dielectric fiber mirror and fiber-tip protection. The fiber pigtail mirror, specifically designed for dichroic operation (i.e., anti-reflection at 976 nm pump wavelength and high-reflection around 2.8 μm laser wavelength), shows high damage density of >10 MW/cm2. An anti-reflection protective film is coated on the input tip of Er3+:ZBLAN fiber and an AlF3 endcap is spliced to the output tip of Er3+:ZBLAN fiber for mitigating the fiber-tip photodegradation and high-power catastrophic failure at 2.8 μm. The compact all-fiber cavity is formed by efficiently connecting the Er3+:ZBLAN fiber with dielectric fiber mirror using the standard FC/PC fiber adaptor. When the 976 nm pump operates in pulsed regime, the all-fiber mid-infrared gain-switched laser can be attained with two states of single-pulse and pulse-burst output. The extracted maximum pulse energy is 4.8 μJ in the single-pulse state, and the shortest pulse width is 426 ns. The pulse-burst mode can generate a maximum average power of 5.291 W and burst energy of 264.55 μJ. This work may offer a promising way to realize the low-cost, all-fiber, high-power and high-energy gain-switched laser at MIR wavelengths.
A Retrospective Study: Are the Multi-Dips in the THz Spectrum during Laser Filamentation Caused by THz–Plasma Interactions?
Authors: Yu Tiancheng , Li Xiaofeng , Lao Li , Zhao Jiayu
Published: July 2024

During the process of terahertz (THz) wave generation via femtosecond laser filamentation in air, as well as through the mixing of THz waves with externally injected plasma filaments, THz waves engage in interactions with the plasma. A characteristic feature of this interaction is the modulation of the THz radiation spectrum by the plasma, which includes the generation of THz spectral dips. This information is essential for understanding the underlying mechanisms of THz–plasma interactions or for inferring plasma parameters. However, a current debate exists on the number of THz spectral dips observed after the interaction, with different opinions of single versus multiple dips, thus leaving the interaction mechanisms still ambiguous. In this work, we retrospectively analyzed the experimental appearance of multiple dips in the THz spectrum and found that the current observations of such dips are predominantly a result of the water vapor absorption with a low spectral resolution. Additionally, we observed that altering the acquisition width of the temporal THz signal also influenced the dips’ number. Hence, in future research, simultaneous attention should be paid to the following two aspects of THz–plasma interactions: (1) It is necessary to ensure a sufficiently wide time-domain window to accurately represent the spectral dip characteristics. (2) The spectral dips should be carefully distinguished from the water absorption lines before being further studied. On the other hand, for the case of a single dip in the THz spectrum, we also put forward a new viewpoint of the resonance between surface plasmon waves and THz waves, which should also be taken into consideration in future studies.
Application of Gap Mode Ultrasensitive P-GERTs in SERS-Based Rapid Detection
Authors: Zhang Mingzhong , Xu Shanshan , Guan Peng-Cheng , Zhang Yue-Jiao , Li Jian-Feng
Published: July 2024

In surface-enhanced Raman scattering (SERS) detection research, the shape, structure, surface modification, and material selection of nanoparticles can significantly impact the SERS intensity. Petal-like gap-enhanced Raman tags (P-GERTs) possess numerous sharp tips and edges, which generate localized electric field enhancements, further amplifying the electric field enhancement effect on neighboring molecules and enhancing the SERS signal. Additionally, the surface of P-GERTs can be modified with functional molecules, enabling their application in the detection of disease biomarkers. Using COVID-19 as an example, the performance of P-GERTs in disease biomarker detection was validated, demonstrating that the signal intensity of this probe can reach 55 times that of regular gold nanoparticles and 36.7 times that of smooth shell gap-enhanced Raman tags (S-GERTs). Furthermore, in combination with magnetically retrievable magnetic bead substrates, the N-protein antigen was specifically detected in a one-step process. N-protein was detected within 15 min using a portable Raman spectrometer. The limit of detection (LOD) for the standard sample was 4.28 pg/mL, and the LOD for the actual throat swab sample system was 25.4 pg/mL. This workflow can be extended to the detection of other biomarkers, making it widely applicable.
Comparative Physiological and Gene Expression Analyses Reveal Mechanisms Involved in Maintaining Photosynthesis Capacity, Alleviating Ion Toxicity and Oxidative Stress of Kentucky Bluegrass under NaCl Treatment
Authors: Wang Rong , Yan Shi-Jie , Liu Chao , Guo Huan , Cui Yan-Nong
Published: July 2024

Kentucky bluegrass (Poa pratensis L.), a widely used cool-season turfgrass, shows a high sensitivity to soil salinity. Clarifying the adaptative mechanisms of Kentucky bluegrass that serve to improve its salt tolerance in saline environments is urgent for the application of this turfgrass in salt-affected regions. In this study, physiological responses of the Kentucky bluegrass cultivars “Explorer” and “Blue Best” to NaCl treatment, as well as gene expressions related to photosynthesis, ion transport, and ROS degradation, were analyzed. The results showed that the growth of “Explorer” was obviously better compared to “Blue Best” under 400 mM NaCl treatment. “Explorer” exhibited a much stronger photosynthetic capacity than “Blue Best” under NaCl treatment, and the expression of key genes involved in chlorophyll biosynthesis, photosystem II, and the Calvin cycle in “Explorer” was greatly induced by salt treatment. Compared with “Blue Best”, “Explorer” could effectively maintain Na+/K+ homeostasis in its leaves under NaCl treatment, which can be attributed to upregulated expression of genes, such as HKT1;5, HAK5, and SKOR. The relative membrane permeability and contents of O2− and H2O2 in “Explorer” were significantly lower than those in “Blue Best” under NaCl treatment, and, correspondingly, the activities of SOD and POD in the former were significantly higher than in the latter. Moreover, the expression of genes involved in the biosynthesis of enzymes in the ROS-scavenging system of “Explorer” was immediately upregulated after NaCl treatment. Additionally, free proline and betaine are important organic osmolytes for maintaining hydration status in Kentucky bluegrass under NaCl treatment, as the contents of these metabolites in “Explorer” were significantly higher than in “Blue Best”. This work lays a theoretical basis for the improvement of salt tolerance in Kentucky bluegrass.
Influence of Habitat and Effects of Salt Stress on Biochemical and Physiological Parameters of Glycyrrhiza uralensis
Authors: Gu Junjun , Jia Tingting , Ma Miao
Published: July 2024

The seeds of Glycyrrhiza uralensis Fisch. used for cultivating are primarily sourced from wild populations. However, the types of habitats where wild G. uralensis grow are diverse. We studied the effects of salinity on the growth, antioxidant capacity, and photosynthetic physiology of two-month-old licorice seedlings from different habitats to evaluate their salt tolerance. With the increasing NaCl concentration, compared with non-salinized habitats, seedlings originating from seeds collected from salinized habitats showed milder inhibition in root biomass and root volume. Also, the crown diameter increased more significantly. Activities of superoxide dismutase, catalase, and peroxidase are higher. Correspondingly, the electrolyte leakage rate of the leaves is low. Their leaves had a higher photoprotection capacity and potential maximum photochemical efficiency of PSII. Net photosynthetic rate, transpiration rate, and stomatal conductance showed less inhibition under 4 and 6 g/kg NaCl treatment. The content of glycyrrhizic acid and glycyrrhetinic acid in their roots was significantly increased under 2 g/kg NaCl treatment and was significantly higher than that of seedlings from non-salinized habitats under the same NaCl treatment. In conclusion, seeds from salinized habitats show improved tolerance to salt stress at the seedling stage, which is attributed to their superior phenotypic adaptability, strong antioxidant, and especially high light protection ability.
A Comparative Study of Two Oroxylum indicum (L.) Kurz. Phenotypes Based on Phytochemicals and Antioxidant Effects, and the Anti-Inflammatory Activity of Leaf and Pod Extracts
Authors: Panomai Pattaraphorn , Thapphasaraphong Suthasinee , Nualkaew Natsajee
Published: July 2024

Indian trumpet tree Oroxylum indicum (L.) Kurz exhibits a wide range of biological activities in all plant parts, including anti-inflammation, antioxidant, and wound-healing activities. In Thailand, there are tall- and short-stem phenotypes. The latter are preferred for commercial cultivation due to their fast growth and lower harvesting cost. This study aimed to compare the chemical profiles and antioxidant effects of leaves and young pods between two phenotypes using principal component analysis (PCA) and then to evaluate the anti-inflammatory potential of the selected phenotype’s plant parts. The biomarker contents were quantified by HPLC. The antioxidants were determined using the DPPH, ABTS, and FRAP models. Nitric oxide (NO) production assays in LPS-induced RAW264.7 macrophages were performed to determine the anti-inflammatory property of the extracts. The PCA revealed that there were no differences in total phenolic content, total flavonoid content, or antioxidant activities between short- and tall-stem phenotypes. Higher potency of the NO-inhibitory effect was achieved from the leaf extract than the pod extract. These results support using the short-stem phenotypes for utilizing the leaf and pod of O. indicum, and suggest choosing the leaf part for further anti-inflammatory product development.
Comparative Effects of Water Scarcity on the Growth and Development of Two Common Bean (Phaseolus vulgaris L.) Genotypes with Different Geographic Origin (Mesoamerica/Andean)
Authors: Galan Paula-Maria , Ivanescu Lacramioara-Carmen , Leti Livia-Ioana , Zamfirache Maria Magdalena , Gorgan Dragoș-Lucian
Published: July 2024

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a most important legume according to the FAO, serves as a staple food for millions of people worldwide, due to its rich protein, carbohydrate, and fiber content, concurrently, and water scarcity is the main factor limiting common bean production. The process of domestication and on-farm conservation has facilitated the development of genotypes with varying degrees of drought stress resistance. Consequently, using landraces as biological material in research can lead to the identification of variants with superior resistance qualities to abiotic stress factors, which can be effectively integrated into breeding programs. The central scope of this research was to find out if different geographic origins of common bean genotypes can determine distinct responses at various levels. Hence, several analyses were carried out to investigate responses to water scarcity in three common bean genotypes, M-2087 (from the Mesoamerican gene pool), A-1988 (from the Andean gene pool) and Lechinta, known for its high drought stress resistance. Plants were subjected to different water regimes, followed by optical assessment of the anatomical structure of the hypocotyl and epicotyl in each group; furthermore, the morphological, physiological, and biochemical parameters and molecular data (quantification of the relative expression of the thirteen genes) were assessed. The three experimental variants displayed distinct responses when subjected to 12 days of water stress. In general, the Lechinta genotype demonstrated the highest adaptability and drought resistance. The M-2087 landrace, originating from the Mesoamerican geographic basin, showed a lower resistance to water stress, compared to the A-1988 landrace, from the Andean basin. The achieved results can be used to scale up future research about the drought resistance of plants, analyzing more common bean landraces with distinct geographic origins (Mesoamerican/Andean), which can then be used in breeding programs.
A Comparative Bryo-Ecological Study of Habitat 3170*: Sites of Particular Phytogeographic Interest in the Mediterranean Area
Authors: Poponessi Silvia , Gigante Daniela , Cogoni Annalena
Published: July 2024

In accordance with the 92/43/EEC “Habitats” Directive, Mediterranean temporary ponds are identified as a priority natural habitat within the European context. They are a very interesting and unique habitat type, as ecological conditions can vary greatly in a short period of time. Due to their small size, many Mediterranean hydrophytic bryophytes typical of this habitat are often overlooked or misinterpreted. Their distribution, habitats, ecology, and strategies are generally poorly understood. Several of them are currently considered rare or endangered in the Mediterranean. As these ponds are particularly sensitive to human activities and natural changes, such bryophytes and associated vegetation communities may be at risk. This study is focused on their floristic variability in different environmental conditions in two sites of particular phytogeographic interest in the Mediterranean area. In the Sardinian Pauli of Giara, 56 taxa (50 Bryophyta and 6 Marchantiophyta) were found, and in the Umbria Piana di Ferretto, 54 taxa (34 Bryophyta and 20 Marchantiophyta) were documented. The taxa from the two areas were analysed and compared. Life strategies, life macroforms, light and moisture preferences, chorological elements, and moisture belts were considered. The data are presented here together with information on the phytogeography and ecology of the species recorded. The findings indicate that a bespoke monitoring strategy and dedicated conservation measures are essential for the effective protection of bryophytes, ensuring the achievement of meaningful and sustainable conservation outcomes.
In Vitro and Ex Vivo Evaluation of Novel Methacrylated Chitosan-PNIPAAm-Hyaluronic Acid Hydrogels Loaded with Progesterone for Applications in Vaginal Delivery
Authors: Afloarea Oana-Teodora , Nacu Isabella , Vereștiuc Liliana , Yilmaz Cătălina Natalia , Panainte Alina Diana , Peptu Cătălina Anișoara , Ostafe Iulia-Giorgiana , Bibire Nela
Published: July 2024

Miscarriage is defined as the loss of a pregnancy before 24 weeks and administration of progesterone in pregnancy has considerably decreased the risk of premature birth. Progesterone (PGT) starting from the luteal phase stabilizes pregnancy, promotes differentiation of the endometrium, and facilitates the implantation of the embryo. Within the present study, novel hybrid hydrogels based on chitosan methacrylate (CHT), hyaluronic acid (HA), and poly(N-isopropylacrylamide) (PNIPAAm) for vaginal delivery of progesterone were evaluated. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) for structural identity assessment and evaluation of their morphological aspects. The ability to swell, the release capacity, enzymatic degradation, cytotoxicity, and mucoadhesion were also reported. The characterized hydrogels demonstrated mucoadhesive properties in contact with the vaginal tissue of swine and bovine origin as substrates, and biodegradability and controlled release in a simulated vaginal environment. Cytocompatibility tests confirmed the ability of the hydrogels and progesterone to support cell viability and growth. The results showed pH-dependent behavior, controlled drug release, good cytocompatibility, and mucoadhesive properties. The hydrogels with higher chitosan amounts demonstrated better bioadhesive properties. This study provides insights into the potential of these hydrogels for the controlled vaginal delivery of progesterone, with promising therapeutic effects and no cytotoxicity observed. The experimental results indicated that a composition with a moderate content of PNIPAAm was suitable for the controlled delivery of progesterone.
Elastomeric Fire and Heat-Protective Materials Containing Functionally Active Microheterogeneous Systems
Authors: Kochetkov Vladimir G. , Kryukova Daria A. , Urzhumov Daniil A. , Novopoltseva Oksana M. , Keibal Natalia A. , Burmistrov Vladimir , Kablov Victor F.
Published: July 2024

This research aims to explore how functionally active structures affect the physical, mechanical, thermal, and fire-resistant properties of elastomeric compositions using ethylene–propylene–diene rubber as a base. The inclusion of aluminosilicate microspheres, microfibers, and a phosphorus–boron–nitrogen–organic modifier in these structures creates a synergistic effect, enhancing the material’s heat-insulating properties by strengthening coke and carbonization processes. This results in a 12–19% increase in heating time for unheated sample surfaces and a 6–17% increase in residual coke compared to existing analogs. Microspheres help counteract the negative impact of microfibers on composition density and thermal conductivity, while the phosphorus–boron–containing modifier allows for controlling the formation of the coke layer.
Synthesis of Cellulose Acetate Butyrate Microspheres as Precursor for Hard Carbon-Based Electrodes in Symmetric Supercapacitors
Authors: Fischer Johanna , Thümmler Katrin , Zlotnikov Igor , Mikhailova Daria , Fischer Steffen
Published: July 2024

Cellulose microspheres have a wide range of applications due to their unique properties and versatility. Various preparation methods have been explored to tailor these microspheres for specific applications. Among these methods, the acetate method using cellulose acetate is well known. However, replacement of the acetate group through the butyrate group significantly extends the variety of morphological properties. In the present work, microspheres based on cellulose acetate butyrate are being developed with modified characteristics in terms of particle size, porosity, surface morphology and the inner structure of the microspheres. While the inner structure of cellulose acetate microspheres is predominantly porous, microspheres prepared from cellulose acetate butyrate are mainly filled or contain several smaller microspheres. Carbon materials from cellulose acetate butyrate microspheres exhibit a high specific surface area of 567 m2 g−1, even without further activation. Activation processes can further increase the specific surface area, accompanied by an adaptation of the pore structure. The prepared carbons show promising results in symmetrical supercapacitors with aqueous 6 M KOH electrolytes. Activated carbons derived from cellulose acetate butyrate microspheres demonstrate an energy density of 12 Wh kg−1 at a power density of 0.9 kW kg−1.