Smooth Surface Research Articles

Learning together: Towards foundation models for machine learning interatomic potentials with meta-learning

The development of machine learning models has led to an abundance of datasets containing quantum mechanical (QM) calculations for molecular and material systems. However, traditional training methods for machine learning models are unable to leverage the plethora of data available as they require that each dataset be generated using the same QM method. Taking machine learning interatomic potentials (MLIPs) as an example, we show that meta-learning techniques, a recent advancement from the machine learning community, can be used to fit multiple levels of QM theory in the same training process. Meta-learning changes the training procedure to learn a representation that can be easily re-trained to new tasks with small amounts of data. We then demonstrate that meta-learning enables simultaneously training to multiple large organic molecule datasets. As a proof of concept, we examine the performance of a MLIP refit to a small drug-like molecule and show that pre-training potentials to multiple levels of theory with meta-learning improves performance. This difference in performance can be seen both in the reduced error and in the improved smoothness of the potential energy surface produced. We therefore show that meta-learning can utilize existing datasets with inconsistent QM levels of theory to produce models that are better at specializing to new datasets. This opens new routes for creating pre-trained, foundation models for interatomic potentials.

In-Vitro Comparison of Titanium Disc Surface Roughness and Bacterial Colonization after Ultrasonic Instrumentation with Three Different Tips.

During implant maintenance, preserving a smooth surface on the machined trans-mucosa abutment is critical to reduce biofilm attachment and colonization. The present study compare the surface roughness and bacterial colonization of machined titanium surfaces after instrumentation with various materials. Forty-four machined Grade 23 titanium discs were instrumented with a round Polyether Ether Ketone (PEEK) tip, a plastic curette tip, or a pure titanium curette tip with piezoelectric devices. Before and after instrumentation, the surface roughness (Ra and Rz) values were analyzed with a profilometer and scanning electron microscopy (SEM). Streptococcus sanguinis was cultured and incubated for 24 hours on the instrumented discs, and colony-forming units (CFU)/mL were obtained for each group. Samples instrumented with the metal ultrasonic tip significantly increased surface roughness compared to the other groups. Thisresulted in greater colonization by S. sanguinis than surfaces instrumented with PEEK tips or the negative control. Samples instrumented with PEEK and plastic tips did not exhibit any statistically significant increase in surface roughness. SEM analysis revealed a significantly rougher surface of discs instrumented with metal compared to discs instrumented with plastic or PEEK tip, despite the possibility of debris from tip dissolution. Our results suggested that instrumentation with metal ultrasonic tips with piezoelectric devices significantly increase machined titanium's surface roughness and elicited higher biofilm formation in vitro. Meanwhile, instrumentation of machined titanium with PEEK or plastic ultrasonic tips did not affect the surface roughness or bacterial adhesion.

Evaluation of Hardness and Wear of Conventional and Transparent Zirconia Ceramics, Feldspathic Ceramic, Glaze, and Enamel

The aim of the study was to compare the hardness, coefficient of friction, and wear experienced by four different ceramic samples: 3Y-TZP zirconium oxide ceramics—Zi—Ceramill Zi (Amman Girrbach), 5Y-PSZ transparent zirconium oxide ceramics—Zol—Ceramill Zolid (Amman Girrbach), Sak—feldspathic ceramics—Sakura Interaction (Elephant), and Glaze (Amman Girrbach). The Vickers hardness of the samples was measured. Friction tests ball-on-disc were performed between the discs of four ceramics and a zirconia ceramic ball, then a premolar tooth as a counter-sample. The mass loss and the friction coefficients of the ceramic samples were determined. The tooth counter-samples were 3D scanned, and enamel attrition depths and mass were measured. The following hardness values (HV1) were obtained: 1454 ± 46 HV1 for Zi, 1439 ± 62 HV1 for Zol, 491 ± 16 HV1 for Sak, 593 ± 16 HV1 for Glaze, and 372 ± 41 HV1 for enamel. The mass losses of the teeth in contact with ceramics were 0.1 mg for Zi, 0.1 mg for Zol, 5.5 mg for Sak, and 4 mg for Glaze. Conventional and transparent zirconium oxide ceramics are four times harder than enamel and three times harder than veneering ceramics. Zirconia ceramics exhibit lower wear and a more homogenous, smoother surface than the other ceramics. Tooth tissues are subject to greater attrition in contact with veneering ceramics than with polished zirconium oxide ceramics.

Improved optical quality of heteroepitaxially grown metal-organic framework thin films by modulating the crystal growth.

Fabricating high-quality thin films of metal-organic frameworks (MOFs) is important for integrating MOFs in various applications. Specifically, optical/electrical devices require MOF thin films that are crystallographically oriented, with closely packed crystals and smooth surfaces. Although the heteroepitaxial growth approach of MOFs on metal hydroxides has been demonstrated to control the orientation of the three crystallographic axes, the fabrication of MOF thin films with both three-dimensional crystallographic orientation and smooth surfaces remains a challenge. In this study, we report the fabrication of high-quality thin films of MOFs with closely packed MOF crystals, smooth surfaces, optical transparency, and crystal alignment by modulating the crystal growth of MOFs using the heteroepitaxial growth approach. High-quality thin films of Cu-paddlewheel-based pillar-layered MOFs are fabricated on oriented Cu(OH)2 thin films via epitaxial growth using acetate ions as modulators to control the crystal morphology. Increasing the modulator concentration results in a uniform crystal shape with a relatively long one-dimensional pore direction and uniform heterogeneous nucleation over the entire film. The MOF thin films fabricated using the modulator exhibit high optical transparency. High-quality MOF thin films with dense and flat surfaces will pave the way for integrating MOFs into sophisticated optical and electrical devices.

Challenges in the diagnosis and treatment of pure non-gestational uterine choriocarcinoma in a child: a case report

BackgroundDiagnosing non-gestational uterine choriocarcinoma in children is challenging because of its rarity and nonspecific imaging findings. Herein, we report a case of non-gestational uterine choriocarcinoma in a child, which was unexpectedly found during exploratory laparotomy and confirmed by histopathological findings. However, the tumor did not respond to chemotherapy.Case presentationA 4-year-old Indonesian female patient was brought into the emergency unit with chief complaint of vaginal bleeding. She had suffered from vaginal spotting 4 months before being admitted to the hospital. Physical examination revealed a distended abdomen in the left lumbar region and a palpable fixed mass with a smooth surface. Abdominal computed tomography scans revealed a large mass (10 × 6 × 12 cm) with fluid density and calcification. Thus, we suspected left ovarian teratoma. The patient’s luteinizing hormone, follicle-stimulating hormone, and lactate dehydrogenase levels were 25.2 mIU/ml, 0.1 mIU/ml, and 406 U/l, respectively. According to the clinical and radiological findings, we decided to perform an exploratory laparotomy and found a tumor originating from the uterus, not the ovarium. We did not observe liver nodules and any enlargement of abdominal lymph nodes. Subsequently, we performed hysterectomy. The histopathological findings supported the diagnosis of choriocarcinoma. The patient was discharged uneventfully on postoperative day 5. Thereafter, the patient underwent nine cycles of chemotherapy, including carboplatin (600 mg/m2 IV), etoposide (120 mg/m2 IV), and bleomycin (15 mg/m2 IV). However, on the basis of the clinical findings of a palpable mass and partial intestinal obstruction, the tumor relapsed soon after the ninth cycle of chemotherapy. Currently, the patient is undergoing chemotherapy again.ConclusionsAlthough pure non-gestational uterine choriocarcinoma is rare, it should be considered as one of the differential diagnoses for intraabdominal tumors in a child, so as to better guide and counsel families regarding the surgical plan and prognosis, respectively. In the present case, the patient’s response to chemotherapy was poor, implying that the treatment of non-gestational choriocarcinoma is still challenging, particularly in the pediatric population.

A taxonomic revision of Garcinia section Garcinia (Clusiaceae) in Thailand

Garcinia section Garcinia (Clusiaceae) is revised for Thailand with three species and one variety, i.e., two native species: G. celebica and G. exigua, and one cultivated species: G. mangostana var. mangostana. Detailed morphological descriptions, illustrations, and an identification key to the species are presented, along with notes on distributions, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. The section is recognized by its terminal inflorescences of simple cymes, or sometimes a solitary flower; flowers with 4 sepals and 4 petals; male flowers often with a pistillode, and stamens united into a single 4-lobed or 4-angled bundle, and with 2-thecous anthers; usually multilocular ovaries and stigmas with distinct or weak lobes and smooth or rough; and fruits with a smooth surface. Three associated synonyms of G. celebica: G. ferrea, G. basacensis, and G. hombroniana, are lectotypified here in a second-step. In Thailand, Garcinia celebica is found in a very wide variety of habitats, at elevations of 0–1,500 m amsl., and is known to be naturally distributed in all floristic regions. G. exigua is found in dry evergreen forest on limestone hills and in littoral dry evergreen forest on limestone hills, at elevations of 50–100 m amsl. in Krabi Province, the peninsular region. G. mangostana var. mangostana is found only in cultivation. Garcinia exigua has a conservation status of Vulnerable [VU B2ab(iii)] and the other two species have a conservation status of Least Concern [LC]. The fleshy pulp surrounding the seeds of two species, G. celebica and G. mangostana var. mangostana is edible and has a sweet-sour taste.

Analysis of the Geometric Accuracy of Wax Models Produced Using PolyJet Molds

The article presents an analysis of the geometric accuracy of wax models produced using PolyJet molds. Photopolymer resin was used to make the molds, and the surface of the model was finished in a gloss mode in the 3D printing process. This allows you to obtain a smooth surface of the molded part model. The geometric accuracy of the models was determined by measurements with the GOM ATOS scanner and analysis of the measurement results in relation to the base model made in the 3D-CAD program. Accuracy analysis was the basis for determining the wear of the mold wear when making subsequent models.

Fenton-Based Treatment of Flax Biomass for Modification of Its Fiber Structure and Physicochemical Properties

The availability of a sustainable technique for degumming lignocellulose fibers is a challenge for the fiber processing industry. Removal of non-cellulosic content from lignocellulose fibers is essential for improving their mechanical and chemical properties, which makes the fibers more suitable for various applications. Herein, a catalytic Fenton-based oxidation process was employed to isolate microcellulose fibers from raw flax fibers. Various complementary methods such as FT-IR/NMR spectroscopy and TGA were used to obtain insight into the thermal behavior of the treated fibers. The morphology of the fibers was studied using Scanning Electron Microscopy (SEM), whereas the surface chemical properties of the fibers was evaluated by a dye-based adsorption method, along with a potentiometric point-of-zero-charge method. To obtain fibers with suitable properties, such as uniform fiber diameter, several Fenton reaction parameters were optimized: pH (7), reaction time (15 h), iron sulfate (2 wt.%), and hydrogen peroxide (10 wt.%). The results indicate that, under the specified conditions, the average diameter of the raw fibers (12.3 ± 0.5 µm) was reduced by 58%, resulting in an average diameter of 5.2 ± 0.3 µm for the treated fibers. We demonstrate that the treated fibers had a lower dye adsorption capacity for methylene blue, consistent with the smoother surface features of the treated fibers over the raw flax fibers. Overall, this study contributes to utilization of the Fenton reaction an efficient oxidation technique for the production of lignocellulose fibers with improved physicochemical properties, such as reduced fiber diameter distribution, in contrast with traditional alkali-based chemical treatment.

Effect of shape and thermal conductivity of microstructured capillary-porous coatings on heat transfer during evaporation and boiling in thin horizontal liquid layers

Investigation results on heat transfer during evaporation and boiling in thin horizontal liquid layers on 2D modulated capillary-porous coatings with a sinusoidal profile in a wide range of relative pressures and layer heights are presented in this paper. Coatings were made on a 3D laser printer using the technology of additive selective laser sintering (SLS). One coating was made of bronze with a modulation wavelength equal to the Laplace constant of the working fluid and two coatings were made of stainless steel and bronze with a doubled wavelength. The experimental data obtained on the coatings were compared with each other and with the values obtained by evaporation and boiling of n-dodecane on a smooth surface under the same conditions. It is shown that in the region of low relative pressures in liquid layers with a height less than the Laplace constant, heat transfer intensification achieved on a sample made of a material with low thermal conductivity (stainless steel) was five times higher as compared to a smooth surface. In the range of relative pressures, when nucleate boiling was observed in the layers, the temperature difference reached on the bronze coatings was approximately 3–4 times less than on a smooth surface. The temperature difference for the stainless steel coating changed little with an increase in the heat flux. In pre-crisis conditions, the temperature difference during boiling on the stainless steel coating was less than on the bronze coatings in the entire range of relative pressures and layer heights. The highest critical heat fluxes were obtained on a bronze coating with a modulation wavelength equal to the Laplace constant.

Hydrophilic coating of membrane by UV-induced radical and cationic curing of photosensitive resins: Lower shrinkage, smoother surface and better anti-fouling performance

Hydrophilic coating is frequently used to enhance the anti-fouling performance of membrane. However, traditional strategies often suffer from defects of cumbersome steps, high energy consumption, and unstable coating. Herein, radical and cationic photopolymerization are used for hydrophilic coating of membranes. Two photosensitive resins were first synthesized either by direct radical copolymerization of 3-ethyl-3-(methacryloyloxy) methyloxetane and 2-hydroxyethyl acrylate (Poly(HEA-EMO)) or through post-polymerization modification of poly(2-hydroxyethyl acrylate) with vinyl groups (Poly(HEA-MA)). Subsequently, hydrophilic coating was conducted on the membrane surface by UV-induced curing of different photosensitive resins, either through radical photopolymerization of vinyl-functional Poly(HEA-MA) or cationic photopolymerization of Poly(EMO-HEA) with pendent oxetane groups. The modified membranes showed enhanced hydrophilicity and underwater oleophobicity than the original membrane. Moreover, the coating (PAN / HEA(C5)) by cationic photopolymerization exhibited lower shrinkage, smoother surface, and more excellent antifouling performance than that by radical photopolymerization. After bovine albumin fouling-cleaning cycles, the flux recovery rate (FRR) of the original membrane was only 68.6 %, while the FRR of PAN / HEA(C5) was as high as 98.0 %. Furthermore, it showed superior long-term operational stability, proving the stability of the coating formed by cationic photopolymerization.

In Vitro Biological Evaluation of an Alginate-Based Hydrogel Loaded with Rifampicin for Wound Care

We report a biocompatible hydrogel dressing based on sodium alginate-grafted poly(N-vinylcaprolactam) prepared by encapsulation of Rifampicin as an antimicrobial drug and stabilizing the matrix through the repeated freeze–thawing method. The hydrogel structure and polymer-drug compatibility were confirmed by FTIR, and a series of hydrogen-bond-based interactions between alginate and Rifampicin were identified. A concentration of 0.69% Rifampicin was found in the polymeric matrix using HPLC analysis and spectrophotometric UV–Vis methods. The hydrogel’s morphology was evaluated by scanning electron microscopy, and various sizes and shapes of pores, ranging from almost spherical geometries to irregular ones, with a smooth surface of the pore walls and high interconnectivity in the presence of the drug, were identified. The hydrogels are bioadhesive, and the adhesion strength increased after Rifampicin was encapsulated into the polymeric matrix, which suggests that these compositions are suitable for wound dressings. Antimicrobial activity against S. aureus and MRSA, with an increased effect in the presence of the drug, was also found in the newly prepared hydrogels. In vitro biological evaluation demonstrated the cytocompatibility of the hydrogels and their ability to stimulate cell multiplication and mutual cell communication. The in vitro scratch assay demonstrated the drug-loaded alginate-grafted poly(N-vinylcaprolactam) hydrogel’s ability to stimulate cell migration and wound closure. All of these results suggest that the prepared hydrogels can be used as antimicrobial materials for wound healing and care applications.

Fabrication of bio-based polymer microcapsule containing fragrances via interfacial photo-initiated crosslinking

Home fragrance (F) products such as laundry detergent and fabric softener use fragrance or essential oils as key components. Typically, the fragrance is enclosed within a polymer. The shell enhances the longevity of the scent due to its durability. However, there is growing environmental concern about utilizing fossil polymers, which decompose slowly and harm the ecology and food chain. Biopolymers are also highly expected to be used as alternative polymers to prepare environmentally friendly microcapsules. This research aims to use poly cinnamyl methacrylate (PCMA) as a biopolymer to prepare microcapsules encapsulated fragrance via interfacial photo-initiated crosslinking. The CMA monomer was prepared by the esterification of cinnamyl alcohol with methacrylic anhydride and synthesized via radical polymerization to form PCMA with a molecular weight of 6,400 g/mol. The PCMA and PCMA/F particles were obtained when the PCMA and PCMA/F droplets dispersed in water were UV-irradiated at 60 W for 8h, giving PCMA and PCMA/F particles contained the highest crosslinking (60–75%). Both PCMA and PCMA/F particles were spherical and smooth outer surfaces where their particle sizes of ∼2 and 7 µm for PCMA and PCMA/F particles were obtained, respectively. The larger size of PCMA/F particles was due to encapsulation, where the encapsulation efficiency of fragrance in PCMA/F particles was approximately 100%. Moreover, the fragrances remaining in the microcapsule particles after 40 days of storage were over 90%. This technique was simple, had high potential microencapsulation, and was environmentally friendly, so the developed microcapsules would express great potential for textiles and laundry formulations.

Karanjin-loaded soya lecithin-based ethosomal nanogel for the therapeutic intervention of psoriasis: formulation development, factorial design based-optimization, in vitro and in vivo assessment

This study aimed to develop and optimize karanjin-loaded ethosomal nanogel formulation and evaluate its efficacy in alleviating symptoms of psoriasis in an animal model induced by imiquimod. These karanjin-loaded ethosomal nanogel, were formulated to enhance drug penetration into the skin and its epidermal retention. Karanjin was taken to formulate ethosomes due to its potential ani-psoriatic activity. Ethosomes were formulated using the cold method using 32 full factorial designs to optimize the formulation components. 9 batches were prepared using two independent variables X 1: concentration of ethanol and X 2: concentration of phospholipid whereas vesicle size (Y 1) and percentage entrapment efficiency (Y 2) were selected as dependent variables. All the dependent variables were found to be statistically significant. The optimized ethosomal suspension (B3) exhibited a vesicle size of 334 ± 2.89 nm with an entrapment efficiency of 94.88 ± 1.24% and showed good stability. The morphology of vesicles appeared spherical with smooth surfaces through transmission electron microscopy analysis. X-ray diffraction analysis confirmed that the drug existed in an amorphous state within the ethosomal formulation. The optimized ethosome was incorporated into carbopol 934 to develop nanogel for easy application on the skin. The nanogel underwent characterization for various parameters including spreadability, viscosity, pH, extrudability, and percentage drug content. The ethosomal formulation remarkably enhanced the skin permeation of karanjin and increased epidermal retention of the drug in psoriatic skin compared to marketed preparation and pure drug. A skin retention study showed that ethosomal nanogel formulation has 48.33% epidermal retention in 6 h. In vivo, the anti-psoriatic activity of karanjin ethosomal nanogel demonstrated significant improvement in psoriasis, indicated by a gradual decrease in skin thickness and scaling as reflected in the Psoriasis Severity Index grading. Therefore, the prepared ethosomal nanogel is a potential vehicle for improved topical delivery of karanjin for better treatment of psoriasis.

Investigation of oil palm fiber reinforced polylactic acid composite extruded filament quality

This study examines the quality of Polylactic Acid (PLA) filament reinforced with Oil Palm Fiber (OPF) for additive manufacturing applications. The research aims to create a composite filament that leverages the advantages of PLA, a biodegradable polymer, and OPF, a natural fiber from the oil palm tree, to enhance mechanical strength, dimensional stability, and printability. The methodology involves crushing the PLA filament and OPF to the desired size using a crusher machine, blending them in different ratios (e.g., 90:10 and 80:20 PLA to OPF), and using a hot-pressing process to bond the components. The resulting pelletized composites are then extruded into filaments using an extruder machine. The quality of the produced filament is assessed based on diameter consistency, surface smoothness, and printability, considering compatibility with 3D printers. The study reveals that composition ratios and processing parameters impact filament quality, leading to challenges such as diameter variations, rapid hardening, breakage, and extruder die clogs. Future recommendations were suggested to optimize compositions, refine processing, explore advanced extrusion, and investigate fiber distribution and bonding for improved filament properties. This research offers valuable insights for creating high-quality OPF-reinforced PLA filaments for additive manufacturing, advancing understanding of filament quality factors, and proposing ways to enhance composite filament performance across applications.

An Improved Large Planar Point Cloud Registration Algorithm

The traditional Iterative Closest Point (ICP) algorithm often suffers from low computational accuracy and efficiency in certain scenarios. It is highly sensitive to the initial pose, has a poor ability to resist interference, and frequently becomes trapped in local optima. Extracting feature points accurately from partially overlapping points with weak three-dimensional features, such as smooth planes or surfaces with low curvature, is challenging using only the traditional ICP algorithm for registration. This research introduces a “First Rough then Precise” registration strategy. Initially, the target position is extracted in complex environments using an improved clustering method, which simultaneously reduces the impact of environmental factors and noise on registration accuracy. Subsequently, an improved method for calculating normal vectors is applied to the Fast Point Feature Histogram (FPFH) to extract feature points, providing data for the Sample Consistency Initial Algorithm (SAC-IA). Lastly, an improved ICP algorithm, which has strong anti-interference capabilities for partially overlapping point clouds, is utilized to merge such point clouds. In the experimental section, we validate the feasibility and precision of the proposed algorithm by comparing its registration outcomes with those of various algorithms, using both standard point cloud dataset models and actual point clouds obtained from camera captures.

Mitigating the deceptive effects of smooth surfaces: subtle surface modifications can eliminate maladaptive drinking attempts by bats

AbstractThe amount of artificial smooth surfaces in the environment increases continuously with urbanization on a global scale. There is growing evidence that smooth surfaces such as windows, solar panels and other objects can serve as sensory traps for many animal species. Artificial smooth surfaces can function as acoustic mirrors, disrupting echolocation of bats and consequently causing maladaptive behaviours such as drinking from and colliding with these surfaces. Therefore, investigating opportunities to mitigate the effects of artificial smooth surfaces is important from a conservation viewpoint. Here, we conducted a field experiment with bats, an ensonification experiment in the laboratory, and a computer simulation, in order to study the effect of mechanical surface modification on the acoustic characteristics of smooth surfaces. In the field experiment, we presented a horizontal smooth plate alone or with strings (diameters between 0.25–2.5 mm) and the behaviour of bats around the plate was video recorded. Bats significantly decreased the frequency of drinking events with increasing diameter of the strings. We also found an indication that a crossed pattern of the strings on the plate may be more effective than a parallel arrangement. The results of the ensonification experiment and the mathematical modelling revealed that a subtle modification of the smooth surfaces with long, linear thin objects can effectively modify the acoustic characteristics of smooth surfaces in general and thereby potentially change the behaviour of bats. Further investigations from sensory, behavioural and ecological viewpoints are proposed to better understand the impact of smooth surfaces on bats and the mitigation solutions that are needed. This research underscores the significance of exploring innovative approaches to minimize the negative impacts of urbanization on wildlife, highlighting the potential of practical interventions to promote coexistence between anthropogenic environments and threatened species.

Template Evolution Induced Relay Self-Assembly for Mesoporous Carbonaceous Materials via Hydrothermal Carbonization.

Constructing carbonaceous materials with versatile surface structures still remains a great challenge due to limited self-assembly methods, especially at high temperatures. This study presents an innovative template evolution induced relay self-assembly (TEIRSA) for the fabrication of large polyoxometalate (POM)-mixed carbonaceous nanosheets featuring surface mesoporous structures through hydrothermal carbonization (HTC). The method employs POM and acetone as additives, cleverly modulating the Ostwald ripening-like process of P123-based micelles, effectively addressing the instability challenges inherent in traditional soft-template methods, especially within the demanding carbohydrate HTC process. Additionally, this method allows for the independent regulation of surface architectures through the selection of organic additives. The resulting nanosheets exhibit diverse surface morphologies, including surface spherical mesopores, 1D open channels, and smooth surfaces. Their unexpectedly versatile properties have swiftly garnered recognition, showing potential in the application of lithium-sulfur batteries.

Folic acid in carboxymethylcellulose/polyethylene oxide electrospun nanofibers: preparation, release and stability.

Folic acid (FA), a synthetically produced compound analogous to vitamin B9, also referred to as vitamin folate, is an essential compound in human health and faces challenges in stability during food processing. This study explores the incorporation of FA into carboxymethylcellulose (CMC) nanofibers using electrospinning to enhance its stability. In this study, optimization of both electrospinning and solution parameters facilitated the fabrication of nanofibers. Furthermore, incorporating FA into CMC/polyethylene oxide (PEO) nanofibers resulted in thinner fibers, with an average diameter of 88 nm, characterized by a flat shape and smooth surface. Fourier transform infrared spectroscopic analysis demonstrated substantial hydrogen bonding interactions between FA and the polar groups present in CMC. This interaction contributed to an encapsulation efficiency of 94.5%, with a yield exceeding 87%. Thermal analysis highlighted mutual interference between CMC and PEO, with FA enhancing the thermal stability and reducing the melting temperatures and enthalpies of PEO, while also increasing the reaction heats of CMC. The encapsulated FA remained stable in acidic conditions, with only 6% degradation over 30 days, demonstrating the efficacy of CMC/PEO nanofibers in safeguarding FA against acidic environments. Moreover, the nanofibers provided a protective barrier against UV radiation, thereby preserving the stability of FA. This study emphasizes the efficacy of CMC/PEO nanofibers as a protective matrix against FA degradation. The findings indicate that this innovative approach could significantly diversify the applications of FA in food fortification, addressing concerns regarding its vulnerability to temperature and hydrolysis reactions during food processing. © 2024 Society of Chemical Industry.

Surface Microstructure Drives Biofilm Formation and Biofouling of Graphene Oxide Membranes in Practical Water Treatment.

Significant progress has been made previously in the research and development of graphene oxide (GO) membranes for water purification, but their biofouling behavior remains poorly understood. In this study, we investigated the biofilm formation and biofouling of GO membranes with different surface microstructures in the context of filtering natural surface water and for an extended operation period (110 days). The results showed that the relatively hydrophilic and smooth Fe(OH)3/GO membrane shaped a thin and spatially heterogeneous biofilm with high stable flux. However, the ability to simultaneously mitigate biofilm formation and reduce biofouling was not observed in the weakly hydrophilic and wrinkled Fe/GO and H-Fe(OH)3/GO membranes. Microbial analyses revealed that the hydrophilicity and roughness distinguished the bacterial communities and metabolic functions. The organic matter-degrading and predatory bacteria were more adapted to hydrophilic and smooth GO surfaces. These functional taxa were involved in the degradation of extracellular polymeric substances (EPS), and improved biofilm heterogeneity. In contrast, the weakly hydrophilic and wrinkled GO surfaces had reduced biodiversity, while unexpectedly boosting the proliferation of EPS-secreting bacteria, resulting in increased biofilm formation and aggravated biofouling. Moreover, all GO membranes achieved sustainable water purification during the entire operating period.

Long-Term Prevention of Biofilm Formation by Polycatechol-Based Supramolecular Assemblies with Low Molecular Weight Polymers on Surfaces.

Achievement of a stable surface coating with long-term resistance to biofilm formation remains a challenge. Catechol-based polymerization chemistry and surface deposition are used as tools for surface modification of diverse materials. However, the control of surface deposition of the coating, surface coverage, coating properties, and long-term protection against biofilm formation remain to be solved. We report a new approach based on supramolecular assembly to generate long-acting antibiofilm coating. Here, we utilized catechol chemistry in combination with low molecular weight amphiphilic polymers for the generation of such coatings. Screening studies with diverse low molecular weight (LMW) polymers and different catechols are utilized to identify lead compositions, which resulted in a thick coating with high surface coverage, smoothness, and antibiofilm activity. We have identified that small supramolecular assemblies (∼10 nm) formed from a combination of polydopamine and LMW poly(N-vinyl caprolactam) (PVCL) resulted in relatively thick coating (∼300 nm) with excellent surface coverage in comparison to other polymers and catechol combinations. The coating properties, such as thickness (10-300 nm) and surface hydrophilicity (with water contact angle: 20-60°), are readily controlled. The optimal coating composition showed excellent antibiofilm properties with long-term (>28 days) antibiofilm activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains. We further utilized the combination of optimal binary coating with silver to generate a coating with sustained release of silver ions, resulting in killing both adhered and planktonic bacteria and preventing long-term surface bacterial colonization. The new coating method utilizing LMW polymers opens a new avenue for the development of a novel class of thick, long-acting antibiofilm coatings.