Surface Structure Research Articles

Kinesin-like motor protein KIF23 maintains neural stemand progenitor cell pools in the developing cortex.

Accurate mitotic division of neural stem and progenitor cells (NSPCs) is crucial for the coordinated generation of progenitors and mature neurons, which determines cortical size and structure. While mutations in the kinesin-like motor protein KIF23 gene have been recently linked to microcephaly in humans, the underlying mechanisms remain elusive. Here, we explore the pivotal role of KIF23 in embryonic cortical development. We characterize the dynamic expression of KIF23 in the cortical NSPCs of mice, ferrets, and humans during embryonic neurogenesis. Knockdown of Kif23 in mice results in precocious neurogenesis and neuronal apoptosis, attributed to an accelerated cell cycle exit, likely resulting from disrupted mitotic spindle orientation and impaired cytokinesis. Additionally, KIF23 depletion perturbs the apical surface structure of NSPCs by affecting the localization of apical junction proteins. We further demonstrate that the phenotypes induced by Kif23 knockdown are rescued by introducing wild-type human KIF23, but not by a microcephaly-associated variant. Our findings unveil a previously unexplored role of KIF23 in neural stem and progenitor cell maintenance via regulating spindle orientation and apical structure in addition to cytokinesis, shedding light on microcephaly pathogenesis.

Hydride-Induced Reconstruction of Pd Electrode Surfaces: A Combined Computational and Experimental Study.

Designing electrocatalysts with optimal activity and selectivity relies on a thorough understanding of the surface structure under reaction conditions. In this study, experimental and computational approaches are combined to elucidate reconstruction processes on low-index Pd surfaces during H-insertion following proton electroreduction. While electrochemical scanning tunneling microscopy clearly reveals pronounced surface roughening and morphological changes on Pd(111), Pd(110), and Pd(100) surfaces during cyclic voltammetry, a complementary analysis using inductively coupled plasma mass spectrometry excludes Pd dissolution as the primary cause of the observed restructuring. Large-scale molecular dynamics simulations further show that these surface alterations are related to the creation and propagation of structural defects as well as phase transformations that take place during hydride formation.

Disruption of the Conjugated π-Electron System of Graphene Oxides Diminishes Their Microwave Reactivity.

Graphenes and graphene-based adsorbents have the potential to be thermally regenerated by microwave irradiation due to their electronic mobility and propensity to absorb microwaves. This article investigates the effect of oxidation on their ability to heat during microwave irradiation in conjunction with their ability to adsorb a polycyclic aromatic hydrocarbon. For this, a series of graphene oxides (GOs) were synthesized, and their chemical properties and surface structures were analyzed systematically. As the oxidation levels increased, the microwave reactivity of GOs decreased notably. This was attributed to the disruption of the sp2-hybridized basal plane despite the introduction of polar oxygen-containing functional groups. The findings of this work indicated the role of the conjugated π-electron system on microwave reactivity, possibly posing a juxtaposition with the influence of polar C-O bonds on dielectric reactivity. In addition, the adsorption of the model compound decreased by oxidation, confirming the decrease in π-π electron donor-acceptor interactions and the increase in the formation of water clusters around oxygen-containing functional groups. This study provides the first mechanistic insight into the relationship between the conjugated π-electron network of graphenes and their microwave reactivity. It paves the way for utilizing microwave irradiation to regenerate spent graphenic adsorbents for water treatment.

Novel green sustainable hydrogel composites based on guar gum and algal species for wastewater remediation

AbstractAn innovative approach was developed for removing very potent heavy metal cations and dyes such as lead (Pb+2), copper (Cu+2) and methylene blue (MB) from simulated solutions at different application conditions. The sorbent material was green hydrogels based on guar gum/poly acrylamide (GG/PAam) fabricated with rice husk core (GG/PAAm/RH) and the optimized formulation was blended with Ulva fasciata and Sargassum dentifolium green algae (denoted as GG/PAAm/RH/Ulva and GG/PAAm/RH/Sarg respectively). The chemical modification process was confirmed by FTIR. The effect of rice husk on the crystallographic and the thermal properties of the hydrogel composites was verified via the XRD and TGA analyses respectively. The surface topography versus structure variation and adsorption process of the aforementioned hydrogels were substantiated by the AFM in order to prove their suitability as effective candidates for wastewater remediation. Different adsorption and kinetic isotherms were applied to precisely describe the adsorption process. The data reveal that the adsorption mechanism best fit multilayer adsorption Freundlich process with qmax values onto GG/PAAm/RH/Ulva and GG/PAAm/RH/Sarg as follows: 50.25 and 73.52 mg g for adsorption of Cu+2, 45.24 and 52.63 mg g for Pb+2, and 51.54 and 68.02 mg g for MB. The reusability investigation proved that the algal-supported sorbents were very successful in removing of reasonable amounts of pollutants after four adsorption–desorption cycles. Graphical abstract

A Listeria monocytogenes aptasensor on laser inscribed graphene for food safety monitoring in hydroponic water

AbstractConsumption of fresh produce, such as leafy greens, is often encouraged as part of a healthy diet. Hence, indoor facilities for hydroponic production of leafy greens are increasingly being established. However, fresh produce entails a higher risk of microbial foodborne illnesses than processed foods. Listeria monocytogenes is a major source of fresh produce contamination and is among the leading causes of severe foodborne illnesses in the United States, with a 16% mortality rate. Tools for rapid monitoring are needed for pathogens such as L. monocytogenes to prevent outbreaks. In this manuscript, we have demonstrated the feasibility of a multi-aptamer approach for development of label-free aptasensors targeting L. monocytogenes in irrigation water for lettuce hydroponic production. We use screening studies with surface plasmon resonance to rationally develop mixtures of relevant aptamers for targeting L. monocytogenes. Based on this screening, multiple aptamers targeting extracellular structures on intact L. monocytogenes were tethered to platinum-modified laser inscribed graphene electrodes. This is the first report of a L. monocytogenes biosensor based on laser inscribed graphene. We show that mixing multiple aptamers with varying affinity improves the diagnostic performance over one aptamer alone in complex sample matrices (lettuce hydroponic water). Multi-aptamer biosensors showed high accuracy for L. monocytogenes and were at least three times more selective than Escherichia coli (Crooks, K12, O157:H7) with an accuracy of 85%. The limit of detection (10 CFU/10 mL) is based on data which were significantly different after calibration toward L. monocytogenes or E. coli (Crooks) and validated against gold standard molecular analysis (polymerase chain reaction). Rapid screening of pathogens is a global need to meet food safety and water quality regulations. This study shows the importance of sensors targeting more than one bacterial surface structure in complex samples relevant to the food-water nexus.

A supervised machine learning tool to predict the bactericidal efficiency of nanostructured surface

The emergence and rapid spread of multidrug-resistant bacterial strains is a growing concern of public health. Inspired by the natural bactericidal surfaces of lotus leaves and shark skin, increasing attention has been focused on the use of mechano-bactericidal methods to create surfaces with antibacterial and/or bactericidal effects. There have been several studies exploring the bactericidal effect of nanostructured surfaces under various combinations of parameters. However, the correlation and synergies between these factors still need to be clarified. Recently machine learning (ML), which enables prediction or decision-making based on data, has been used in the field of biomaterials with promising results. In this study, we explored ML in nanotechnology to investigate the antimicrobial potential of nanostructured surfaces. A dataset of nanostructured surfaces and their antimicrobial properties was built by extracting the published literature. Based on the literature review and the distribution of our dataset, 70% bactericidal efficiency was selected as a practical benchmark for our classification model that balances stringent bactericidal performance with achievable targets in diverse conditions. Subsequently, we developed an ML classification model, which demonstrated an 81% accuracy in its predictive capability. A regression model was further developed to predict the value of bactericidal efficiency for nanostructured surfaces. Feature importance analysis of the ML models suggested that nanotopographical features have a greater influence on bactericidal properties than material properties, thus providing insight into the principles of the mechano-bactericidal effect of nanostructured surfaces. Overall, this ML model tool could help researchers to effectively select and design the parameters of the surface structure prior to experimentation, thereby improving the timeliness and reducing the number of experiments and the associated costs.Graphical

Effect of soil profile-related parameters on seismic performance of ductile reinforced concrete building frames in California

Strong ground motions with specific site characteristics can lead to structural damage. Comprehending the effects of site characteristics on the dynamic response of structures is crucial for evaluating seismic performance and thereby implementing design that can mitigate potential damage. This study explores how the site characteristics, including the average shear wave velocity, soil depth to rock, and site period, influence the seismic response of reinforced concrete buildings. Soil column models were created using 319 soil profiles located in California and were employed to perform the nonlinear site response analysis of 80 rock motions to generate surface motions. Subsequently, low-to high-rise reinforced concrete moment-resisting frames with four, eight, twelve, and twenty stories that are representative of California were modeled to conduct nonlinear structural analyses. In this process, the influence of the three site characteristics on the response of the surface motions and structures was investigated. This investigation revealed that structural responses tend to increase when the average shear wave velocity ranges from 180 to 360 m/s or when the depth exceeds 135 m. Additionally, structures with a natural period exceeding 1 s were found to be more vulnerable as the number of stories increased. The outcomes will promote the development of seismic design methods based on different site characteristics.

Surface Structure Dependent Activation of Hydrogen over Metal Oxides during Syngas Conversion.

Despite the extensive studies on the adsorption and activation of hydrogen over metal oxides, it remains a challenge to investigate the structure-dependent activation of hydrogen and its selectivity mechanism in hydrogenation reactions. Herein we take spinel and solid solution MnGaOx with a similar bulk chemical composition and study the hydrogen activation mechanism and reactivity in syngas conversion. The results show that MnGaOx-Solid Solution (MnGaOx-SS) is a typical Mn-doped hexagonal close-packed (HCP) Ga2O3 with a Ga-rich surface. Upon exposure to hydrogen, Ga-H and O-H species are simultaneously generated. Ga-H species are highly active but unselective in CO activation, forming CHxO, and ethylene hydrogenation, forming ethane. In contrast, MnGaOx-Spinel is a face-centered-cubic (FCC) spinel phase featuring a Mn-rich surface, thus effectively suppressing the formation of Ga-H species. Interestingly, only part of the O-H species are active for CO activation while the O-H species are inert for olefin hydrogenation over MnGaOx-Spinel. Therefore, MnGaOx-Spinel exhibits a higher activity and higher light-olefin selectivity than MnGaOx-SS in combination with SAPO-18 during syngas conversion. These fundamental understandings are essential to guide the design and further optimization of metal oxide catalysts for selectivity control in hydrogenations.

Surface‐Assisted Passivation Growth of 2D Ultrathin β‐Bi2O3 Crystals for High‐Performance Polarization‐Sensitive Photodetectors

Abstract2D nonlayered materials (NLMs) have garnered considerable attention due to unique surface structure and bright application prospect. However, owing to the strong interatomic forces caused by intrinsic isotropic chemical bonds in all directions, the direct synthesis of ultrathin and large area 2D NLMs remains a tremendous challenge. Here, the surface‐assisted passivation growth strategy is designed to synthesize ultrathin and large size β‐Bi2O3 crystals with the thickness down to 0.77 nm and the lateral size up to 163 µm. These results are primarily ascribed to the bonding between Se atoms and the unsaturated Bi atoms on the surface of β‐Bi2O3, resulting in the surface passivation and promoting the obtaining of ultrathin β‐Bi2O3. Strikingly, the photodetectors based on β‐Bi2O3 flakes exhibit a high photoresponsivity of 71.91 A W−1, an excellent detectivity of 6.09 × 1013 Jones, a remarkable external quantum efficiency of 2.4 × 104%, an outstanding anisotropic photodetection and excellent UV imaging capability at 365 nm. This work sheds light on the synthesis of 2D ultrathin NLMs and promotes their applications in multifunctional optoelectronics.

Experimental and ANN based process optimization for bioremediation of Cr6+ and Cd2+ by green adsorbent prepared from Artocarpus Heterophyllus leaves

The effective removal of toxic pollutants from water and waste water, is a challenging issue for environmental protection. In the present work, the performance of Artocarpus Heterophyllus (jackfruit) leaves have been examined for reduction of toxic Cr (VI) and Cd (II) from synthetic wastewater. Characterization of the adsorbent was made to evaluate the surface morphology and chemical composition, by Scanning Electron Micrograph (SEM) and Energy Dispersive Spectroscopy (EDS). Characteristic surface groups [Fourier Transform Infra-Red (FTIR)], surface area and surface structure [Brunauer–Emmett–Teller, (BET)] were also determined. The influences of various factors which control the removal process were studied experimentally in batch method and optimized. High removal efficiency was obtained at pH ≤ 2 for Cr (VI); and for Cd (II) it was ≥ 6. The experimental data were tested using different kinetic and isotherm models. Artocarpus Heterophyllus leaf was found suitable to remove 99.7 % Cr (VI) and 98.4 % Cd (II) from a strength of 20 mg L-1 solution at 0.5 g L-1 adsorbent concentration, at their respective favorable pHs. The reaction followed pseudo second order kinetic model for both the cases. The calculated sorption energy of 16.16 and 12.68 kJ mol-1, suggested chemical nature for both the cases. Desorption studies showed the effective reuse of Artocarpus Heterophyllus leaf for three times. The relatively high equilibrium adsorption capacity of 32.29 and 20.37 mg g-1 for Cr (VI) and Cd (II) respectively, suggested use of Artocarpus Heterophyllus leaf as a reasonably good green bio-adsorbent. The modeling of the complex adsorption process based on artificial neural network approach exhibited reliability and high degree of proficiency (R values of 0.999) in the model’s prediction and experimental data indicated its applicability in forecasting removal efficiency for both the metal ions.

Bioinspired interfacial engineering of multiscale micro/nano-structured surfaces with robust superhydrophobic and tunable adhesion

Creating superhydrophobic surfaces with varying liquid–solid adhesion holds significant applications in waterproofing, lab-on-chip, and self-cleaning. Biological superwetting surfaces, such as lotus leaf and rose petal, leverage hierarchical micro/nanoscale surface structures together with low-surface-energy chemicals, to synergistically tune their adhesion. However, existing synthetic technologies encounter great difficulty in constructing sophisticated micro/nano architectures for robust, adhesive superhydrophobic surfaces, especially on fabrics. Here, we present a bioinspired interfacial engineering methodology of “artificial papillae + glue” which allows the construction of tunable multiscale micro/nano structures for superhydrophobic fabrics with mechanical robustness (mechanical friction up to 100 cycles) and varying adhesion (69.4–216.5 µN). For our methodology, artificial papillae with tunable 3D topological architectures, fluorinated alky chains, and hydrosilylation-reactive C = C groups, are designed and synthesized as the robust anchoring groups to different concentrations of polydimethylsioxane (PDMS) glue and applied to hydrophilic substrates. The PDMS-dominated surfaces form microwrinkles with high adhesion, ideal for microdroplet manipulation and hemostasis, meanwhile artificial papillae-dominated surfaces offer low adhesion and excellent self-cleaning properties. This biomimetic “artificial papillae + glue” strategy enables the creation of tunable multi-scale micro/nanostructures for robust adhesive antiwetting interfaces, offering promising applications in droplet manipulation, hemostasis, and beyond.

Polyglot entrainment for higher dimensional neuronal models

The entrainment of biological oscillators is a classic problem in the field of dynamical systems and synchronization. This paper explores a novel type of entrainment mechanism referred to as polyglot entrainment [Khan et al., “The emergence of polyglot entrainment responses to periodic inputs in vicinities of Hopf bifurcations in slow–fast systems,” Chaos 32, 063137 (2022)] (multiple disconnected 1:1 regions for a range of forcing amplitude) for higher dimensional nonlinear systems. Polyglot entrainment has been recently explored only in two-dimensional slow–fast models in the vicinity of Hopf bifurcations (HBs). Heading toward generality, in this research, we investigate the phenomenon of polyglot entrainment in higher-dimensional conductance-based models including the four-dimensional Hodgkin-Huxley model and its reduced three-dimensional version. We utilize dynamical systems tools to uncover the mechanism of entrainment and geometric structure of the null surfaces to explore the conditions for the existence of polyglot entrainment in these models. In light of our findings, in the vicinity of HB, when an unforced system acts as a damped oscillator and the fixed point is located near a cubic-like manifold, polyglot entrainment is observed.

The Chemistry of Bimetallic Surfaces - Evolution of an Atomic-scale Picture

In this contribution, we will review the concepts and principles used to characterize and discuss the structure, stability, adsorption properties and catalytic reactivity of bimetallic surfaces in an atomic-scale picture. Starting from early stages, we will emphasize recent experimental and theoretical findings that resulted in a rapidly improving atomic-scale understanding of adsorption and catalytic surface reactions on these surfaces. While examples are often taken from our own work, the resulting insights are of general validity.

Fabrication of Hierarchically-Porous Diatomite Scaffolds for Dye Adsorption by a Dual-templating Approach

Compared to single-scale porous structures, multi-scale porous materials are distinguished by their unique hierarchical architecture composed of macro-, meso-, and micro-pores. These materials are widely adapted in nature and endowed with high surface area, improved transport efficiency, and reduced weight due to their structural design. Such characteristics lead to various applications, especially in filtration and adsorption. In this study, a dual-templating method integrating freeze casting and 3D-printing sacrificial templating techniques was employed to develop multi-scale porous scaffolds with pore sizes distributed across three distinct length scales. Gyroid, a type of triply periodic minimal surface (TPMS) structure, was selected for the millimeter-scale channel design because of their high permeability, non-tortuous fluid pathways, and interconnected pores. Moreover, periodic gyroid structures can be described by mathematical equations, allowing for the systematic designs of 3D models. By varying the volume fractions of the 3D-printed gyroid templates and the cooling rates during the freeze casting process, pore sizes at both millimeter and micrometer scales can be tuned to achieve desired structures. Furthermore, the smallest pores were provided by diatomites, the fossilized silica-based algae with inherent nanoscale pores, offering extremely high surface area and porosity. Permeability experiments were conducted to further explore the influence of multi-scale pores on fluid transportation properties. Results showed that scaffolds with three scales of pore sizes (millimeter, micrometer, and nanometer) exhibited up to 58 times increase in permeability compared to those with two scales of pore sizes (micrometer and nanometer). Additionally, by leveraging the inherent functional groups on diatomites, multi-scale porous scaffolds were used in methylene blue dye adsorption experiments, revealing a dye removal efficiency of 63%. In conclusion, this study integrated freeze casting and additive manufacturing methods for multi-scale porous ceramics with tunable structural features and functionalities, which can be applied in wastewater treatment, ultra-lightweight structural materials and other engineering fields.

Thermal performance enhancement for gas turbine blade trailing edge cooling with topology-optimized printable diamond TPMS lattice

The gas turbine blade trailing edge region is a critical concern in the cooling design due to its narrow characteristics, which limit the implementation of cooling structures. With rapid development in additive manufacturing, many complex cooling techniques have been designed to enhance thermal performance and improve flow uniformity for gas turbine blade trailing edges. This study generates a high thermal performance cooling structure for the trailing edge channel using topology optimization and a Diamond-type triply periodic minimal surface (TPMS) structure. The optimized model is obtained by infilling the Diamond structure in the intermediate densities from the topology optimization, where the objective is to maximize heat transfer under constant input power. The flow path constraints are also included to achieve better uniform flow distribution. The optimized models are compared with the baseline circular pin fin and uniform Diamond network at Reynolds numbers of 10,000 to 30,000. The results show that the uniform Diamond structure provides obviously higher heat transfer than the pin fins by up to 314.3 %. The optimized models obtain lower heat transfer but considerably reduce pressure loss by about twice compared to the uniform Diamond case. Even though the pressure loss of the optimized model is higher than in the pin fins, the thermal performance enhancement is increased by 139.7 %-150.2 %. The fluid flow and heat transfer in the optimized model are distributed more uniformly than in the pin fins. Furthermore, a high-resolution CT scan is employed to assess the manufacturability of the proposed design, printed by laser powder bed fusion at a scale of realistic gas turbine blades. The findings show the feasibility of 3D printing for next-generation gas turbine blades.

Enhancing bioactive compounds extraction from Noni leaves (Morinda citrifolia) by enzymes-assisted extraction

Noni leaves provide several health benefits as food and traditional medicines due to their bioactive compounds. This study investigated the preliminary effects of cellulase and hemicellulase assisted extraction on bioactive compounds extraction from Noni leaves compared to maceration technique. Cellulase and hemicellulase-assisted extraction formed small holes on the extracts surface and provided rough surface, angular and fragmentation structures indicated some breakdown of Noni leaves cell wall after enzyme reaction. There was a significant difference of the extracts particle size between the samples from cellulase assisted extraction and hemicellulase assisted extraction while no significant difference was observed between the samples from maceration technique and cellulase assisted extraction. For antioxidant activity, cellulase assisted extraction provided the highest antioxidant activity (92.83 and 73.05 mg TEAC/ g of sample which was determined by DPPH and FRAP method respectively). However, hemicellulase extraction exhibited the lowest antioxidant activity (36.38 and 33.33 mg TEAC/ g of sample in DPPH and FRAP method respectively). Cellulase-assisted extraction provided higher asperuloside content (0.14±0.01 μM/ g of sample) as compared to maceration technique (0.13±0.01 μM/ g of sample) and hemicellulase-assisted extraction (0.05±0.01 μM/ g of sample). These results can lead to the use of green technology for bioactive compounds extraction from plant sources for use as a medical and functional food ingredient.

Sb-anchoring single-crystal engineering enables ultra-high-Ni layered oxides with high-voltage tolerance and long-cycle stability

Ni-rich layered oxides are promising cathodes for Li-ion batteries, but the inherent structural defects result in severe surface/bulk degradation during long cycling, especially at high cutoff voltage. Herein we propose a Sb-anchoring single-crystalline engineering to enhance the microstructural and electrochemical stability of ultra-high-Ni layered oxides, where the surface-enriched Sb doping inhibits Li-Ni mixing, suppressing the undesired layered to mixed/rock-salt phase transformation; the bulk-doped Sb rivets into Ni sites, reinforcing the bulk phase stability; the single-crystal endows enhanced crack resistance and reduced surface area, preventing surface parasitic reactions and the subsequent proliferation of cathode electrolyte interfaces. In-situ XRD reveals an essential correlation between cycle stability and phase reversibility, whereas Sb doping into both surface and bulk structures showcases a continuous anchoring effect, largely enhancing the phase transformation reversibility. DFT calculations prove a high oxidation tolerance, as Ni2+ diffusion barrier is higher than the pure cathode. A representative Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2 cathode exhibits a high-voltage up to 4.6V, and a Li(Ni0.9Co0.05Mn0.05)0.99Sb0.01O2//graphite full-cell demonstrates an ultra-high capacity retention of 93.4% after 1000 cycles at 1C in 3.0−4.2V. This simple and efficient cathode engineering will promote the promising application of Ni-rich layered oxides in high-energy Li-ion batteries.

Phase field fracture in elastoplastic solids: a stress-state, strain-rate, and orientation dependent model in explicit dynamics and its applications to additively manufactured metals

Phase field models have gained growing popularity in analysing fracture behaviour of materials. However, few have been explored to simulate dynamic ductile fracture to date. This study aims to develop a phase field framework considering strain rate, stress state, and orientation dependent ductile fracture under dynamic loading. Firstly, governing equations of displacement and phase fields are formulated in an explicit finite element framework. Secondly, constitutive relations are established with a hypoelastic-plasticity framework, encompassing the influence of material orientation and strain rate on both plasticity and fracture initiation. Stress states dependent fracture initiation is also considered. Thirdly, finite element implementation and corotational formulation for constitutive equations are derived. To validate the proposed model, finally, additively manufactured samples, involving material-level and crack propagation specimens are tested under dynamic loading conditions. Overall, the proposed phase field model can properly reproduce the experimental force-displacement curves and crack paths. Uniaxial tension tests reveal that a higher strain rate can lead to a higher hardening curve and lower ductility. Other material specimens further demonstrate the capability to predict stress state and orientation dependent dynamic fracture. To simulate dynamic crack paths accurately, it is necessary to consider anisotropic fracture initiation. Lastly, the phase field model was applied for the first time to predict the dynamic response of triply periodic minimal surface (TPMS) structures. Dynamic crack patterns were effectively captured, and the fracture mechanisms were thoroughly analysed. This study provides an explicit phase field framework for dynamic ductile fracture, with applications to additively manufactured materials and structures.

Antibacterial cellulose-based membrane with heat dissipation and liquid transportation for food packaging applications

Food spoilage, caused by fungi and bacteria, has drawn increasing attention due to the lack of suitable temperature and humidity control, resulting in food waste and health risks. It is still a great challenge to develop green packaging materials with excellent antibacterial activities and effective temperature/humidity control for food preservation. Herein, a new strategy is proposed to obtain food packaging material with antibacterial ability, heat dissipation, and liquid transportation functions. In this strategy, Zn-Al layered double hydroxide (LDH)@cellulose was obtained by extracting cellulose from sugarcane husks, followed by in-situ growth of LDH nanosheets on the surface of cellulose. Then, asymmetric structured packaging material, namely cellulose acetate/LDH@cellulose (CALC) membrane, was prepared by the combination of electrospinning and hydrophobic modification. The characterization results confirmed that the CALC membrane exhibits asymmetric surface structure and wettability properties, endowing heat dissipation and liquid transportation for food packaging applications. Due to the asymmetric reflectivity and infrared emissivity, the CALC membrane exhibited excellent heat dissipation properties with a surface temperature of 10.3℃, which is lower than that of commercial food packaging material. Furthermore, the excellent liquid transport properties of the CALC membrane are demonstrated by the fact that water can penetrate from the hydrophobic side to the hydrophilic side within 32s, providing the appropriate storage temperature and dry environment for foods. In addition, compared with PE film, the CALC membrane also has antibacterial properties and UV resistance, which is beneficial to improving the storage conditions for foods. This study shows that the developed CALC membrane and corresponding design strategy can be extended for the preparation of other packaging materials for applications in research and food industrial fields.

Purification, structural identification, in vitro hypoglycemic activity and digestion characteristics of polysaccharides from the flesh and peel of wampee (Clausena lansium)

In this study, two polysaccharides were isolated from the flesh and peel of wampee, termed as PWP-F and PWP-P respectively, and their structural characteristics, in vitro antioxidant and hypoglycemic activities and digestion were investigated. Results indicated the molecular weight of PWP-F was higher than that of PWP-P and they were both mainly composed of galactose and arabinose. Both polysaccharides exhibited α-type and β-type glycosidic linkages based on FTIR analysis. NMR spectroscopy revealed that PWP-F mainly consisted of α-Araf-(1→, →3,5)-α-Araf-(1→, →2,5)-α-Araf-(1→, →4) → β-Galp-(1 → and α-GalpA-(1→, while PWP-P was composed of α-Araf-(1→, →3)-α-Araf-(1→, →5)-α-Araf-(1→, →3,6) → β-Galp-(1→ and α-GalpA-(1→. Scanning electron microscopy showed that PWP-P had more porous surface structure compared to PWP-F. Moreover, PWP-P exhibited superior antioxidant activity and significant inhibition of both α-glucosidase and α-amylase compared to PWP-F. Specifically, PWP-P demonstrated mixed inhibition against α-glucosidase and α-amylase. In vitro digestion results showed the molecular weight, polysaccharide and reducing sugar content of PWP-F and PWP-P decreased after simulative gastrointestinal digestion. Overall, PWP-P has great potential as a kind of new antioxidant and hypoglycemic agent.