bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular engineering of nitrogen-rich helicene based organic semiconductors for stable perovskite solar cells
Authors: Wei Yuefang , Cai Yaohang , He Lifei , Zhang Yuyan , Yuan Yi , Zhang Jing , Wang Peng
Published: September 2023

A helicene-based organic semiconductor with exceptional glass transition temperature at 230 °C was prepared for 85 °C durable perovskite solar cells.
Structurally divergent enantioselective synthesis of benzofuran fused azocine derivatives and spiro-cyclopentanone benzofurans enabled by sequential catalysis
Authors: Khuntia Rupkumar , Mahapatra Sanat Kumar , Roy Lisa , Chandra Pan Subhas
Published: September 2023

We have developed a divergent approach for the catalytic asymmetric synthesis of skeletally different benzofuran fused azocine derivatives and spiro-cyclopentanone benzofurans. The methodology involves sequential catalysis: chiral H-bonding catalysis and Lewis base catalysis.
Molecular hybrids of trivacant lacunary polyoxomolybdate and multidentate organic ligands
Authors: Jimbo Atsuhiro , Li Chifeng , Yonesato Kentaro , Ushiyama Tomoki , Yamaguchi Kazuya , Suzuki Kosuke
Published: September 2023

This work presents a method for synthesizing hybrids of trivacant lacunary polyoxomolybdates [PMo9O34]9− and multidentate organic ligands, including carboxylates and phosphonates, by using a lacunary species stabilized with removable pyridyl ligands.
Emerging frontiers in aromaticity
Authors: Solà Miquel , Fernández Israel , Merino Gabriel
Published: September 2023

This themed collection reflects on the relevance of aromaticity in modern chemistry by highlighting the most recent discoveries and views, offering a selection of articles on a wide variety of relevant subjects.
A phosphorus-based olefin linked fully conjugated polymeric ligand for palladium-catalyzed trans-selective dicarbofunctionalization of internal alkynes
Authors: Kumar Pramod , Maji Biplab
Published: September 2023

Phosphorus is introduced in sp2 carbon (CC) linked fully conjugated porous organic polymers (POPs) and has been exploited in synthetically challenging and selectively competitive multicomponent dicarbofunctionalization reactions.
Bridging the gap between basic research and application: a half-cell setup for high current density measurements of Ir-based oxygen evolution reaction catalysts on porous transport electrodes
Authors: Jiménez Pablo Collantes , Wiberg Gustav K. H. , Sievers Gustav W. , Brüser Volker , Arenz Matthias
Published: September 2023

Innovative PTE setup enhances laboratory benchmarking of next-generation catalysts for the oxygen evolution reaction under technologically relevant conditions.
Robust packet loss compensation in the cloud‐based TT&C receiver using a predictive tracking loop with RBF network identification
Authors: Fan Yimin , Liu Tian , Li Ting , Zhang Yi , Liu Liu , Liu Yang
Published: September 2023

In recent years, ground‐based aerospace tracking, telemetry and control (TT&C) systems have been shifting towards an IP‐based cloud TT&C network architecture to improve signal transmission efficiency and system flexibility. However, this new architecture presents new challenges for the performance of tracking loops in the cloud‐based TT&C receiver. The authors present a predictive compensation tracking loop that addresses the problem of packet loss. The loop utilises radial basis function (RBF) online network identification for robust carrier and code frequency offset tracking. To account for packet loss, the phenomenon is modelled as a Bernoulli random process, and the predictive compensation loop uses the trained RBF network to maintain the system's tracking state. When normal data are received again, the loop can track the received information well and align the frequency offset locking state. The authors compare the performance of the proposed predictive compensation tracking loop with traditional loop tracking performance using data hold strategies under different packet loss rates. The results demonstrate the effectiveness of the proposed approach in maintaining stable tracking and solving in the discontinuous reception of the loop under packet loss environments. The proposed predictive compensation tracking loop offers a practical solution for addressing packet loss, which is a common issue in real‐world applications.
Veranstaltungsbericht
Authors: Marks Lara , Döblitz Ralf
Published: September 2023

Das Motto zum Tag der Organspende in diesem Jahr war – wie ein Jahr zuvor in Mainz – „Zeit, Zeichen zu setzen“. Nach dem ökumenischen Gottesdienst in der Basilika St. Lambertus fand auf dem Schadowplatz, mitten im Herzen von Düsseldorf, das Begleitprogramm mit Infoständen, Organmodellen und vielen Aktionen statt. Dies war der 41. Tag der Organspende, der in dieser Form veranstaltet wurde.
Magneto-responsive hyaluronan hydrogel for hyperthermia and bioprinting: Magnetic, rheological properties and biocompatibility
Authors: Vítková L. , Kazantseva N. , Musilová L. , Smolka P. , Valášková K. , Kocourková K. , Humeník M. , Minařík A. , Humpolíček P. , Mráček A. , Smolková I.
Published: September 2023

Magneto-responsive soft hydrogels are used for a number of biomedical applications, e.g., magnetic hyperthermia, drug delivery, tissue engineering, and neuromodulation. In this work, this type of hydrogel has been fabricated from hyaluronan (HA) filled with a binary system of Al2O3 nanoparticles and multicore magnetic particles (MCPs), which were obtained by clustering of superparamagnetic iron oxide FeOx NPs. It was established that the presence of diamagnetic Al2O3 has several positive effects: it enhances the hydrogel storage modulus and long-term stability in the cell cultivation medium; prevents the magnetic interaction among the MCPs. The HA hydrogel provides rapid heating of 0.3 °C per min under exposure to low amplitude radio frequency alternating magnetic field. Furthermore, the magneto-responsive hydrogel was successfully used to encapsulate cells and extrusion-based 3D printing with 87±6% cell viability, thus providing a bio-ink. The combination of high heating efficiency, softness, cytocompatibility, and 3D printability of magnetic HA hydrogel leads to a material suitable for biomedical applications.
3D photopolymerized microstructured scaffolds influence nuclear deformation, nucleo/cytoskeletal protein organization, and gene regulation in mesenchymal stem cells
Authors: Donnaloja Francesca , Raimondi Manuela Teresa , Messa Letizia , Barzaghini Bianca , Carnevali Federica , Colombo Emanuele , Mazza Davide , Martinelli Chiara , Boeri Lucia , Rey Federica , Cereda Cristina , Osellame Roberto , Cerullo Giulio , Carelli Stephana , Soncini Monica , Jacchetti Emanuela
Published: September 2023

Mechanical stimuli from the extracellular environment affect cell morphology and functionality. Recently, we reported that mesenchymal stem cells (MSCs) grown in a custom-made 3D microscaffold, the Nichoid, are able to express higher levels of stemness markers. In fact, the Nichoid is an interesting device for autologous MSC expansion in clinical translation and would appear to regulate gene activity by altering intracellular force transmission. To corroborate this hypothesis, we investigated mechanotransduction-related nuclear mechanisms, and we also treated spread cells with a drug that destroys the actin cytoskeleton. We observed a roundish nuclear shape in MSCs cultured in the Nichoid and correlated the nuclear curvature with the import of transcription factors. We observed a more homogeneous euchromatin distribution in cells cultured in the Nichoid with respect to the Flat sample, corresponding to a standard glass coverslip. These results suggest a different gene regulation, which we confirmed by an RNA-seq analysis that revealed the dysregulation of 1843 genes. We also observed a low structured lamina mesh, which, according to the implemented molecular dynamic simulations, indicates reduced damping activity, thus supporting the hypothesis of low intracellular force transmission. Also, our investigations regarding lamin expression and spatial organization support the hypothesis that the gene dysregulation induced by the Nichoid is mainly related to a reduction in force transmission. In conclusion, our findings revealing the Nichoid's effects on MSC behavior is a step forward in the control of stem cells via mechanical manipulation, thus paving the way to new strategies for MSC translation to clinical applications.
Depth profiles of akaganéite, goethite and maghemite on A1010, HPS and weathering steel panels after wet-dry corrosion tests
Authors: Sawicki Jerzy A.
Published: September 2023

The panels of high chromium steel (A1010), high-performance steel (HPS 70W) and weathering steel (WS) were exposed to accelerated salt-spray corrosion test for 1 week and to less aggressive test for additional 13 weeks. After the tests, the corrosion products formed were extracted layer after layer and examined as a function of their depth with Mössbauer transmission spectroscopy. In the case of A1010 steel, the amounts of goethite (α-FeOOH) and akaganéite (β-FeOOH) were almost equal along the depth of the corroded layer up to ∼20 μm. The rust layers on HPS and WS panels were much thicker, respectively up to ∼0.6 mm and ∼1 mm, poorly adherent and contained mostly akaganéite near the metal–rust interface, α-FeOOH increasingly further away, and – after long exposure – also up to 20% Fe as maghemite (γ-Fe2O3). Formation of β-FeOOH near the interface was promoted by chloride concentrated by spray-dry cycles. The microstructure and depth profiles of identified species, and especially the role of β-FeOOH, are discussed.
Magnetite supported on different zeolites as highly efficient heterogeneous Fenton catalysts for methylene blue removal
Authors: Quynh Ho Gia , Thanh Huynh Van , Phuong Nguyen Thi Truc , Hung Lam Hoa , Dung Nguyen Van , Long Nguyen Quang
Published: September 2023

By using a simple but upgraded impregnation– precipitation method, this study successfully synthesized the magnetite loaded on zeolite catalysts. The catalysts were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) methods. Moreover, the study investigated their catalysis activity by using them for the methylene blue (MB) degradation via a heterogeneous Fenton process in the presence of an oxidizing agent (H2O2). The study discovered the effects of different parameters on the MB decolorization efficiency, such as the amounts of catalyst, the initial concentration of hydrogen peroxide, pH of the solution, and the durability of the catalysts. Experimental results revealed that an almost complete degradation was achieved with an initial methylene blue concentration of 50 ppm, a solution pH of 3, a H2O2concentration of 1.95 mM, and a catalyst dosage of 0.6 gL−1within 60 minutes. Furthermore, after four to five cycles, the Fe3O4/zeolite catalysts showed high stability for Fenton degradation of MB, indicating that these catalysts might be promising choices for wastewater remediation.
Effects of sodium silicate on the growth and starch content in seeds of Mungbean (Vigna radiate L.) under salt stress
Authors: Tran Thang Thanh
Published: September 2023

Mungbean is known as an essential legume with high nutritional value for human beings. They are not only a source of vegetable proteins but they are also rich in vitamins and minerals. Salinity stress affects negatively mungbean growth, especially at germination and seedling stages. Thus, finding measures to limit the impact of salinity stress will have positive effects on mungbean production. The present study investigates the effectiveness of sodium silicate application (6, 12, 18, 24 mM) in alleviating the negative impact of salinity stress on seed germination and seedling growth. Physiological and biochemical changes during the growth of mungbean were analyzed. Our experiments showed that salinity stress dramatically impeded the germination of mungbean seeds. Under the salinity condition (125 mM NaCl), the germination index decreased by approximately 65 % compared to control plants. Salinity stress caused a significant decrease in leaf chlorophyll and leaf relative water content, whereas respiration rate, leaf epicuticular wax and carotenoid content increased in comparison to control plants. The application of 12 mM sodium silicate improved plant performances under salinity stress, as indicated by the increase in fruit and seed number, seed weight (72.33 mg), and starch content (0.51 g g−1) in seeds. Moreover, sodium silicate treatment induced an increase in chlorophyll a content (4.00 mg g−1), carotenoid content (2.50 mg g−1), and epicuticular wax content (3.67 µg cm−2) in the leaves of plants under salt stress. These results were scientific evidence that might help us to understand the role of Si in the improvement of the salt tolerance of mungbean.
Fabrication of cellulose-based aerogel from banana stem for thermal insulation and water treatment
Authors: Chau Quyen N D , Le Quyen T M , Huynh Ha K P , Nguyen Son T
Published: September 2023

Herein banana stem was used as a source of cellulose to fabricate a novel material that can be used in thermal insulation and water treatment. Characterization of the fabricated aerogels was carried out. The results expressed morphology, appearances, and thermal stability of the aerogels. The cellulose-based aerogels expressed low density (about 0.043 g/cm3), super high porosity (up to 98.11%), high compressive Young’s Modulus value (up to 365.5 kPa), ultra-low thermal conductivity (0.0362 to 0.0367 W/mK), and the oil adsorption capability up to 17.42 g/g. By applying a simple and green procedure, our banana stem aerogel could be used for further applications in material industry as those for thermal insulation and oil adsorption.
Calculating groundwater recharge using saturated-unsaturated flow modeling
Authors: Thanh Hoa Nguyen Thi , Song Giang Le
Published: September 2023

Groundwater in the unpressurized aquifer is divided into saturated and unsaturated zones, which are separated by the water table. Calculating the groundwater flow in the saturation zone is performed by solving the Laplace equation. Whereas the movement of groundwater in an unsaturated zone requires solving Richards’ equation. The difficulty in calculating groundwater flows is not only due to the high nonlinearity of the Richards’ equation. The problem is even more difficult because the two equations Richards and Laplace have completely different mathematical natures. In addition, in the area near the water table, the two states of saturation and unsaturation alternately change. In this paper, an algorithm for solving one-dimensional Richards’ equations by the finite volume method is introduced. The algorithm allows the calculation of the distribution of moisture in the unsaturated zone and accurate determination of the position of the water table in the interaction with the saturated zone
Excellent catalytic activity of NiPd/C nanocatalysts for anodic oxidation of methanol in alkaline media
Authors: Nguyen Son Truong , Minh Vu Tan , Boi Ly Tuyen , Cao Ngan Ngo Hoang , Nguyen Minh Truong Xuan , Nguyen Kha Minh , Ngo Thang Manh , Huynh Ha Ky Phuong , Nguyen Duy Phuc Thanh , Nguyen Hoang , Phan Anh N
Published: September 2023

In this study, nanocatalyst NiPd was synthesized via a successful two-stage reduction process with NaBH4 and PVP. More specifically, the first stage involves NaBH4 reduction of Ni2+ ion to metallic Ni. Afterwards, Pd would be coated on the surface of the aformentioned Ni particles by reducing Pd2+ using the remaining NaBH4. The effect of experimental parameters on the synthesis and catalytic activity of the nanocatalysts, such as reaction temperature (30, 40, 50, 60, 70 °C), reaction time (60, 90, 120, 150, 180 minutes), Pd:Ni mole ratio (1:10, 3:10, 5:10, 7:10, 9:10). were investigated by X-ray diffraction (XRD), Energy dispersive spectroscopy (EDX), and transmission electron microscopy (TEM) were used to analyse the surface structure, composition and morphology of the catalyst samples. The catalytic activity and stability of the resulting NiPd/C catalysts were investigated towards the methanol oxidation reaction (MOR) in alkaline environment by cyclic voltammetry (CV) and chronoamperometry (CA) techniques. The results showed that the highest catalytic activity was found for the sample synthesized at 50 °C with 120-minute reaction time and the Pd:Ni molar ratio of 5:10. The influence of KOH and methanol concentrations on the catalytic activity of NiPd/C for methanol oxidation reaction in alkaline medium was also investigated. The results demonstrated the promising potential of NiPd/C nanomaterials as catalyst materials for the anodic layer in direct methanol fuel cells (DMFCs).
Patterns in the Distribution and Abundance of the Post-Outbreak Population of the Coconut Leaf Beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) in Albay, Philippines
Authors: Galicia G L , Medina C dR , Velasco L R I , Ceballo F A , Rebancos C M
Published: September 2023

Field monitoring of the coconut leaf beetle (CLB) population in old stands (more than 7 years old) and young stands of coconut (3-5 years old) was conducted in Albay Philippines where an outbreak of the pest occurred in 2006. The study was conducted to characterize the changes in the population of the CLB over time and space and to relate these changes to the infestation pattern, age of palms, development and reproduction of the pest, growth, and development of the coconut leaf. The spatial distribution of the CLB population as well as the infested palms were aggregated throughout the monitoring period based on the Index of dispersion and Lloyd’s mean crowding. Development time and reproduction of CLB is inferred to be synchronous with the emergence of each leaflet in the spear of coconut which has an average of 23 days before another leaflet emerges. This complemented the biology studies where CLB was able to complete from egg to adult in 34.33±2.59 and 32.00±0.93 days in females for both laboratory and greenhouse studies. The infestation of CLB was shown not to spread even if there was an increase in the population.
Sustainable Utilization of King Coconut Husk as a Feedstock in Biochar Production with the Highest Conversion Efficiency and Desirable Properties
Authors: Ekanayaka E. M. G. N. , Dissanayake D. K. R. P. L. , Udumann S. S. , Dissanayaka D. M. N. S. , Nuwarapaksha T. D. , Herath H. M. S. K. , Atapattu Anjana J.
Published: September 2023

King coconut husk biochar is a soil amendment that can potentially increase soil fertility in degraded soils under perennial coconut plantations. This experiment was conducted in a laboratory to investigate the properties of biochar produced with different cut sizes of king coconut husk under different pyrolysis conditions. Full husk, 1/2nd cuts, 1/4th cuts, 1/8th cuts, and chips of king coconut husk were pyrolyzed at 300°C and 500°C temperatures for 20, 30, 40, 60, 90, and 180 minutes of residence times, respectively. Even though partial pyrolysis was observed at 300°C under a few residence times, complete pyrolysis was observed at 500°C under all six residence times. Increasing the residence time caused a statistically significant (P<0.05) reduction in biochar yield at 500°C due to the removal of chemical compounds and gases by thermal decomposition under prolonged high-temperature conditions, resulting in low biochar output. The fixed carbon, volatile matter, ash, and pH levels have not improved substantially due to prolonged residence time. The highest level of fixed carbon was detected after 60 minutes of residence time with the least amount of ash and volatile components. Using biochar made from king coconut husk with a 1/4th cut size as a soil amendment with minimal processing and drying activity will be economically viable to increase carbon sequestration.
Pest and Disease Challenges, Control Strategies as Well as Policy Support for The IPM Program on Coconut
Authors: Hosang M L A , Alouw J C , Rahma  , Sambiran J W , Pinaria B A N , Kardinan Agus
Published: September 2023

Coconut played an important role in humans as an estate commodity. Many efforts have been made to increase coconut production through intensification, extensification, and diversification but those efforts have not given maximum results yet, likewise, assembling superior coconut varieties also have been carried out, to produce superior coconut varieties such as Tall coconut, Dwarf coconut, Hybrid coconut, but this is also not been able to increase coconut production optimally. On the other hand, several factors can cause the decline in coconut production, such as severe damage caused by major pests and diseases. The list of highlighted major pests in this article was as follows, Rhynchophorus spp., Cyrtotrachelus sp., Oryctes rhinoceros, Amblypelta sp., and Opisina arenosella. Three species of it were categorized as new emerging pests in Indonesia: Cyrtotrachelus sp., Amblypelta sp., and O. arenosella. Cyrtotrachelus sp. has been reported to cause damage, and mortality of coconut plants reached 10.63%, as well as Amblypelta sp., as reported in North Sulawesi Province, while the O. arenosella has been reported to caused severe damage to coconut plantations in West Java. For diseases, are Bud Rot Disease and Nut Fall Disease caused by Phytophthora palmivora. In 2022, Nias Yellow Dwarf coconuts in Tiniawangko Village, South Minahasa, North Sulawesi, infected with Bud Rot disease by 31.53%, causing coconut plants to die, and Nut Fall Disease causing a decrease in production by 25.00%. In addition, it was found that coconut plants died due to infection with an Unknown Disease. Integrated Pest Management (IPM) is an effective approach to control all pests and diseass, where possible. This is a combination of methods (pesticides, physical controls such as site hygiene, and biological controls) to minimize the use of pesticides and the cost of control. The IPM program can run well if there is policy support from the government.
Quercetin nanoformulations: recent advancements and therapeutic applications
Authors: Kaur Simrandeep , Goyal Ayushi , Rai Arya , Sharma Akshay , Ugoeze Kenneth Chinedu , Singh Inderbir
Published: September 2023

Quercetin is a natural bioflavonoid and is an inevitable part of a person’s daily diet. It exhibits anti-inflammatory, anti-oxidant, anti-cancer, anti-microbial effects and is used for the treatment of several diseases like cancer, cardiovascular ailments, and microbial infections. The major limitations of quercetin are low water solubility, less chemical stability, low bioavailability, and short biological half-life. All these major drawbacks can be overcome by its encapsulation in various nanocarriers (nanoparticles, nanoliposomes, nanocrystals, nanomicelles, etc). Such quercetin encapsulated nanoformulations displayed enhanced solubility, stability, bioavailability, high encapsulation efficiency, controlled drug release and extended systemic circulation time period. Quercetin loaded nanocarriers can easily pass across different barriers like blood brain barrier (BBB), skin barriers, mucosal membrane, hence providing target site specific delivery. They also exhibited improved therapeutic effects such as enhanced anti-cancer, anti-diabetic, anti-microbial, anti-inflammatory, anti-psoriasis, anti-oxidant, anti-asthmatic, anti-acne, skin-whitening, hepatoprotective, photoprotective, neuroprotective, nephroprotective and cardioprotective actions. Major health issues associated with nanoformulations are risk of cytotoxicity, oxidative stress, DNA damage, and mutations that can be minimised with continual advancements in nanotechniques. The present review discusses quercetin, its historical background, pharmacokinetics, mechanism of action, and therapeutic applications with major emphasis on the quercetin nanoformulations such as nanoparticles, nanoemulsions, nanoliposomes, nanocrystals, nanosuspensions and nanomicelles that enhances its physicochemical stability, solubility, and therapeutic applications. Also this review includes different quercetin nanoformulations developed for colon cancer and colorectal cancer treatment, brief description of pre-clinical & clinical studies, toxicological concerns, challenges & opportunities, future aspects, patents and marketed quercetin products.
Green nanosilica and highly efficient removal of methylene blue
Authors: Thuadaij Pattaranun , Yodyingyong Supan
Published: September 2023

A new precipitation method has been developed for improving the production of nanosilica that is faster and more environmentally friendly. The study investigates the effects of different acid types and concentrations, as well as aging times, to determine the optimal conditions for preparing nanosilica from sugarcane bagasse ash (SCBA). Nanosilica synthesised with citric acid exhibits a higher specific surface area (554.01 m2 g−1) and yield (88.54%) compared to those synthesised with sulfuric, oxalic, and acetic acids. X-ray diffraction (XRD) patterns and transmission electron microscope (TEM) images show that the synthesised nanosilica has an amorphous silica phase with a particle diameter of approximately 5.6 nm. The applicability of the synthesised nanosilica as an adsorbent for methylene blue (MB) is studied. Various conditions such as adsorbent dosage, contact time, and initial concentration of MB are evaluated. The results reveal that the synthesised nanosilica has a high adsorption capacity (232.29 mg g−1) and removal efficiency (R%) of 90% for MB. The experimental results align with the Freundlich model and can be used for effective dye removal. The development of a simple and environmentally friendly method for synthesising nanosilica with superior adsorption properties is an important contribution to the field of waste management and provides a useful tool for tackling environmental pollution caused by organic dyes.
Revealing flat bands and hybridization gaps in a twisted bilayer graphene device with microARPES
Authors: Jiang Zhihao , Hsieh Kimberly , Jones Alfred J H , Majchrzak Paulina , Sahoo Chakradhar , Watanabe Kenji , Taniguchi Takashi , Miwa Jill A , Chen Yong P , Ulstrup Søren
Published: September 2023

Controlling the electronic structure of two-dimensional materials using the combination of twist angle and electrostatic doping is an effective means to induce emergent phenomena. In bilayer graphene with an interlayer twist angle near the magic angle, the electronic dispersion is strongly modified by a manifold of hybridizing moiré Dirac cones leading to flat band segments with strong electronic correlations. Numerous technical challenges arising from spatial inhomogeneity of interlayer interactions, twist angle and device functionality have so far limited momentum-resolved electronic structure measurements of these systems to static conditions. Here, we present a detailed characterization of the electronic structure exhibiting miniband dispersions for twisted bilayer graphene, near the magic angle, integrated in a functional device architecture using micro-focused angle-resolved photoemission spectroscopy. The optimum conditions for visualizing the miniband dispersion are determined by exploiting the spatial resolution and photon energy tunability of the light source and applied to extract a hybridization gap size of

(
0.14
±
0.03
)

 eV and flat band segments extending across a moiré mini Brillouin zone. In situ electrostatic gating of the sample enables significant electron-doping, causing the conduction band states to shift below the Fermi energy. Our work emphasizes key challenges in probing the electronic structure of magic angle bilayer graphene devices and outlines conditions for exploring the doping-dependent evolution of the dispersion that underpins the ability to control many-body interactions in the material.
Optimizing process for pulsed laser additive manufacturing of nickel-based single crystal superalloy
Authors: Ci Shiwei , Liang Jingjing , Li Jinguo , Zhou Yizhou , Sun Xiaofeng , Cheng Zonghui
Published: September 2023

The relationship between pulsed laser processing parameters and epitaxial growth of alloy is essential to additive manufacturing technology in repairing and manufacturing nickel-based single crystal (SX) superalloys. In this paper, orthogonal experiments of Laser Direct Energy Deposition (DED-L) process have been designed to optimize the process for the epitaxial growth of the SX superalloy. The relationship between process parameters and epitaxial growth of SX superalloy is established in a radar map, which shows that low laser power, pulse width and powder feeding rate help epitaxial growth in the DED-L process. It is implied that increasing the powder feeding rate value in the process range decreases the epitaxial growth rate of the molten pool and increases manufacturing efficiency. The size of the cladding layer width is greatly influenced by laser power (reached 44%) and pulse width (reached 38%). The deposited heigh of the cladding layer is mainly influenced by pulse width (reached 45%) and powder feeding rate (reached 42%). The process parameters have a similar level (approximately 33%) of influence on the powder using efficiency.
Analysis of heat transfer performance and thermo-hydraulic characteristics of graphene nanofluids: impact of sedimentation effects
Authors: Lakshmanan Periyannan , Periyasamy Saravanan , kanagarajan Saranya , Dhairiyasamy Ratchagaraja
Published: September 2023

This study investigates the heat transfer performance and thermo-hydraulic characteristics of nanofluids containing graphene nanoparticles in a water and ethylene glycol mixture. Results show that both nanofluid samples, with concentrations of 0.15% and 0.10% by volume, experience increased heat transfer coefficients (h) compared to the base fluid under various operating conditions, with average reductions of approximately 21% and 26%, respectively. Additionally, the nanofluids exhibit higher friction losses and pressure drops compared to the base fluid. The friction factor and head loss increased by 8.7% and 7.7% for the 0.15% concentration sample and 12.7% and 12.4% for the 0.10% concentration sample. These findings indicate that the thermo-hydraulic performance of the nanofluids is unsatisfactory, offering limited advantages over the base fluid. Surprisingly, the sedimentation of nanoparticles in the test section leads to unexpected results. Contrary to typical observations, the higher concentration sample shows a lower head loss. This discrepancy is attributed to nanoparticle sedimentation, increasing friction factors, and pressure drops. The study also examines the thermal conductivity and viscosity of the nanofluids. It is found that even at low concentrations, graphene nanofluids exhibit higher thermal conductivity than the base fluid. The dynamic viscosity slightly increases with concentration, aligning well with theoretical models. Further research is needed to optimize nanofluid performance and address these issues in practical applications.
Machine learning (ML)-assisted surface tension and oscillation-induced elastic modulus studies of oxide-coated liquid metal (LM) alloys
Authors: Hossain Kazi Zihan , Kamran Sharif Amit , Tavakkoli Alireza , Khan M Rashed
Published: September 2023

Pendant drops of oxide-coated high-surface tension fluids frequently produce perturbed shapes that impede interfacial studies. Eutectic gallium indium or Galinstan are high-surface tension fluids coated with a ∼5 nm gallium oxide (Ga2O3) film and falls under this fluid classification, also known as liquid metals (LMs). The recent emergence of LM-based applications often cannot proceed without analyzing interfacial energetics in different environments. While numerous techniques are available in the literature for interfacial studies- pendant droplet-based analyses are the simplest. However, the perturbed shape of the pendant drops due to the presence of surface oxide has been ignored frequently as a source of error. Also, exploratory investigations of surface oxide leveraging oscillatory pendant droplets have remained untapped. We address both challenges and present two contributing novelties- (a) by utilizing the machine learning (ML) technique, we predict the approximate surface tension value of perturbed pendant droplets, (ii) by leveraging the oscillation-induced bubble tensiometry method, we study the dynamic elastic modulus of the oxide-coated LM droplets. We have created our dataset from LM’s pendant drop shape parameters and trained different models for comparison. We have achieved >99% accuracy with all models and added versatility to work with other fluids. The best-performing model was leveraged further to predict the approximate values of the nonaxisymmetric LM droplets. Then, we analyzed LM’s elastic and viscous moduli in air, harnessing oscillation-induced pendant droplets, which provides complementary opportunities for interfacial studies alternative to expensive rheometers. We believe it will enable more fundamental studies of the oxide layer on LM, leveraging both symmetric and perturbed droplets. Our study broadens the materials science horizon, where researchers from ML and artificial intelligence domains can work synergistically to solve more complex problems related to surface science, interfacial studies, and other studies relevant to LM-based systems.
Atrial fibrillation-associated electrical remodelling in human induced pluripotent stem cell-derived atrial cardiomyocytes: a novel pathway for antiarrhythmic therapy development
Authors: Seibertz Fitzwilliam , Rubio Tony , Springer Robin , Popp Fiona , Ritter Melanie , Liutkute Aiste , Bartelt Lena , Stelzer Lea , Haghighi Fereshteh , Pietras Jan , Windel Hendrik , Pedrosa Núria Díaz i , Rapedius Markus , Doering Yannic , Solano Richard , Hindmarsh Robin , Shi Runzhu , Tiburcy Malte , Bruegmann Tobias , Kutschka Ingo , Streckfuss-Bömeke Katrin , Kensah George , Cyganek Lukas , Zimmermann Wolfram H , Voigt Niels
Published: September 2023

Aims

Atrial fibrillation (AF) is associated with tachycardia-induced cellular electrophysiology alterations which promote AF chronification and treatment resistance. Development of novel antiarrhythmic therapies is hampered by the absence of scalable experimental human models that reflect AF-associated electrical remodelling. Therefore, we aimed to assess if AF-associated remodelling of cellular electrophysiology can be simulated in human atrial-like cardiomyocytes derived from induced pluripotent stem cells in the presence of retinoic acid (iPSC-aCM), and atrial-engineered human myocardium (aEHM) under short term (24 h) and chronic (7 days) tachypacing (TP).

Methods and results

First, 24-h electrical pacing at 3 Hz was used to investigate whether AF-associated remodelling in iPSC-aCM and aEHM would ensue. Compared to controls (24 h, 1 Hz pacing) TP-stimulated iPSC-aCM presented classical hallmarks of AF-associated remodelling: (i) decreased L-type Ca2+ current (ICa,L) and (ii) impaired activation of acetylcholine-activated inward-rectifier K+ current (IK,ACh). This resulted in action potential shortening and an absent response to the M-receptor agonist carbachol in both iPSC-aCM and aEHM subjected to TP. Accordingly, mRNA expression of the channel-subunit Kir3.4 was reduced. Selective IK,ACh blockade with tertiapin reduced basal inward-rectifier K+ current only in iPSC-aCM subjected to TP, thereby unmasking an agonist-independent constitutively active IK,ACh. To allow for long-term TP, we developed iPSC-aCM and aEHM expressing the light-gated ion-channel f-Chrimson. The same hallmarks of AF-associated remodelling were observed after optical-TP. In addition, continuous TP (7 days) led to (i) increased amplitude of inward-rectifier K+ current (IK1), (ii) hyperpolarization of the resting membrane potential, (iii) increased action potential-amplitude and upstroke velocity as well as (iv) reversibly impaired contractile function in aEHM.

Conclusions

Classical hallmarks of AF-associated remodelling were mimicked through TP of iPSC-aCM and aEHM. The use of the ultrafast f-Chrimson depolarizing ion channel allowed us to model the time-dependence of AF-associated remodelling in vitro for the first time. The observation of electrical remodelling with associated reversible contractile dysfunction offers a novel platform for human-centric discovery of antiarrhythmic therapies.
Floral Diversity and Pollination Syndromes in Agave subgenus Manfreda
Authors: MacNeill Bryan N , Ortiz-Brunel Juan Pablo , Rodríguez Aarón , Ruiz-Sánchez Eduardo , Navarro-Moreno Jesús , Hofford Nathaniel P , McKain Michael R
Published: September 2023

Synopsis

The genus Agave is an ecological keystone of American deserts and both culturally and economically important in Mexico. Agave is a large genus of about 250 species. The radiation of Agave is marked by an initial adaptation to desert environments and then a secondary diversification of species associated with pollinator groups, such as hummingbirds and nocturnal moths. Phylogenetic analyses place Agave subgenus Manfreda, or the “herbaceous agaves,” in a monophyletic clade that likely evolved in part as an adaptation to novel pollination vectors. Here, we present a morphological and observational study assessing the evolution of floral form in response to pollinator specialization within this understudied group. We found significant visitation by hummingbirds and nocturnal moths to several species within the Agave subgenus Manfreda. These observations also align with our morphological analyses of floral organs and support the evolution of distinct pollination syndromes. We found that not all floral morphology is consistent within a pollination syndrome, suggesting hidden diversity in the evolution of floral phenotypes in Agave. We also characterize the morphological variation between herbarium and live specimens, demonstrating that special consideration needs to be made when combining these types of data. This work identifies the potential for studying the functional evolution of diverse floral forms within Agave and demonstrates the need to further explore ecological and evolutionary relationships to understand pollinator influence on diversification in the genus.
A Review on Analytical Methods for Tigecycline Estimation From Its Bulk and Dosage Form
Authors: Rakholiya Bansi , Shah Priyangi , Patel Yash , Patel Gayatri , Patel Samir , Patel Archita
Published: September 2023

Background

Tigecycline (TIG) is a third-generation glycylcycline derivative used as an antimicrobial and anticancer agent for the past few years. Its intricate structure makes it more vulnerable toward degradation under the influence of various environmental factors and leads to the generation of impurities. Due to its stability issues, TIG is available as a lyophilized powder for injection. The analysis of TIG becomes a cumbersome task for analysts due to its instability in solution form. As TIG works as a life-saving drug, it is important to review its analytical methods for its quality control.

Objective

The present review discusses various analytical methodologies for determining TIG from its bulk, lyophilized powder, pharmacopoeial methods and factors responsible for its instability.

Methods

The present review represents the analysis of data reported in the literature from 1999-2022 for the analysis of TIG.

Results

Numerous alternative analytical techniques such as UV-visible spectrophotometry, spectrofluorimetric methods, RP-HPLC (reversed-phase high-performance liquid chromatography) and FT-IR (Fourier transform infrared), and electrophoresis has been reported for quantification, identification, and characterization of TIG.

Conclusions

Several analytical techniques are available to be used as a quality control tool for tigecycline, including HPLC without derivatization, whereas the fluorescence technique requires derivatization using acidic dye. A few methods require tedious pre-sample preparation techniques, become time-consuming, and involve using one or more organic solvents; there is a need to develop eco-friendlier methods for analyzing tigecycline.

Highlights

Various analytical methods such as spectrometric, fluorimetric and chromatographic methods have been discussed for estimation of TIG from its bulk and different dosage form.
Green Method for Evaluation of Marbofloxacin Tablets by HPLC and Evaluation of Interchangeability With UV and Turbidimetric Methods
Authors: de Oliveira Aline Sinzervinch , de Oliveira Naiara Raica Lopes , de Oliveira Neto Jerônimo Raimundo , Tavares Layla Lopes , Kogawa Ana Carolina
Published: September 2023

Background

Marbofloxacin (MAR) is a veterinary antimicrobial, marketed in injectable solution, oral suspension, and tablets. MAR has no monograph for tablet evaluation in official compendiums. High Performance Liquid Chromatography (HPLC) methods present in the literature for evaluating MAR in tablets do not follow the principles of green and sustainable analytical chemistry.

Objective

A green, clean, and sustainable method by HPLC was developed and validated to evaluate the content and stability of MAR in tablets, in addition to comparing it with other methods available in the literature.

Method

A C8, 5 µm, 4.6 × 150 mm (ACE®) column, purified water with 0.2% formic acid–ethanol (70:30, v/v) as the mobile phase, and a flow rate of 0.7 mL/min at 296 nm were used.

Results

The method was linear over a concentration range of 1–10 μg/mL, selective for tablet matrix and forced degradation, precise with relative standard deviations (RDS) less than 5%, accurate with recovery of 99.99%, and robust to changes in the mobile phase, flow rate, wavelength, equipment, and column brand. The retention time for MAR was approximately 3.1 min.

Conclusions

The method can be used in routine analysis of MAR in tablets in chemical-pharmaceutical laboratories. Furthermore, it can be used to verify the stability of MAR-based products and proved to be interchangeable with spectrophotometric method in the UV region and turbidimetric microbiological method.

Highlights

A green method for evaluation of marbofloxacin tablets by HPLC was developed and validated. Additionally, it has been shown to be interchangeable with UV and turbidimetric methods.
Learning style of medical students and their preferred teaching methodologies in a medical college in Nepal: a descriptive cross-sectional study
Authors: Pathak Prajwol , Neupane Sulav , Tamang Sujan , Neupane Sunischit , Dhungana Vinayak , Khatri Shirish , Gautam Rochak , Mainali Gaurab
Published: September 2023

Introduction:

Each individual learns differently. Honey and Mumford classified learning styles as activists, reflectors, theorists, and pragmatists. This study was conducted to find out the frequency of learning styles and preferred teaching methodology of students in a medical college in Nepal.

Methods:

Two hundred MBBS students participated in this study who were selected through a stratified sampling technique using students’ class year as a stratum, followed by a simple random sampling method. Honey and Mumford’s learning style questionnaire was used to determine learning styles. A self-developed questionnaire was used to find their preferred teaching methodology.

Results:

Of the total, 139 males and 61 females participated in the study where 9 (4.5%) students were activists, 21 (10.5%) were theorists, 112 (56%) were reflectors, and 24 (12%) were pragmatists. Out of all participants, 50 (25%) preferred interactive learning, 47 (23.5%) preferred problem-based learning, 59 (29.5%) preferred self-study, and only 2 (1%) students preferred one-way lectures and guest speakers each.

Conclusion:

The majority of students were reflectors (56%) and pragmatists (12%). Most students preferred self-study (29.5%) but one-way lectures were less preferred. Medical institutions should align teaching strategies with the learning styles of medical students to improve their understanding and performance.
Lean Performance Indicators and Facilitators of Outcomes in U.S. Public Hospitals
Authors: Roey Tyler , Hung Dorothy Y. , Rundall Thomas G. , Fournier Pierre-Luc , Zhong Athena , Shortell Stephen M.
Published: September 2023

Goal:

This study investigated the association between Lean and performance outcomes in U.S. public hospitals. Public hospitals face substantial pressure to deliver high-quality care with limited resources. Lean-based management systems can provide these hospitals with alternative approaches to improve efficiency and effectiveness. Prior research shows that Lean can have positive impacts in hospitals ranging in ownership type, but more study is needed, specifically in publicly owned hospitals.

Methods:

We performed multivariable regressions using data from the 2017 National Survey of Lean/Transformational Performance Improvement. The data were linked to publicly available hospital performance data from the Agency for Healthcare Research and Quality and the Centers for Medicare & Medicaid Services. We examined 11 outcomes measuring financial performance, quality of care, and patient experience and their associations with Lean adoption. We also explored potential drivers of positive outcomes by examining Lean implementation in each hospital, measured as the number of units using Lean tools and practices; leader commitment to Lean principles; Lean training and education among physicians, nurses, and managers; and use of a daily management system among C-suite leaders and managers.

Principal Findings:

Lean adoption and implementation were associated with improved performance in U.S. public hospitals. Compared with hospitals that did not adopt Lean, those that did had significantly lower adjusted inpatient expenses per discharge and higher-than-average national scores on the appropriate use of medical imaging and timeliness of care. The study results also showed marginally significant improvements in patient experience and hospital earnings before interest, taxes, depreciation, and amortization margins. Focusing on these select outcomes, we found that drivers of such improvements involved the extent of Lean implementation, as reflected by leadership commitment, daily management, and training/education while controlling for the number of years using Lean.

Practical Applications:

Lean is a method of continuous improvement centered around a culture of providing high-value care for patients. Our findings provide insight into the potential benefits of Lean in U.S. public hospitals. Notably, they suggest that leader buy-in is key to success. When executives and managers support Lean initiatives and provide proper training for the workforce, improved financial and operational performance can result. This commitment, starting with upper management, may also play a broader role in the effort to reform healthcare while having a positive impact on patient care in U.S. public hospitals.