Intact Morphology Research Articles

Catharanthus roseus-assisted bio-fabricated zinc oxide nanoparticles for promising antibacterial potential against Klebsiella pneumoniae.

This study emphasized on the synthesis of zinc oxide nanoparticles (ZnO NPs) in an environmentally friendly manner from the extract of Catharanthus roseus leaves and its antibacterial assessment against the pneumonia-causing pathogen Klebsiella pneumoniae. This simple and convenient phytosynthesis approach is found to be beneficial over conventional methods, wherein plants serve as excellent reducing, capping, and stabilizing agents that enables the formation of ZnO NPs without the use of harmful chemicals. The formation of ZnO NPs was confirmed through several characterization techniques such as UV-visible spectroscopy, XRD, FT-IR, SEM, HR-TEM, and EDX. XRD analysis revealed high polycrystallinity with crystallite size of approximately 13nm. SEM and HR-TEM revealed the hexagonal structure of ZnO NPs with the particle size range of 20-50nm. The EDX shows the elemental purity without any impurity. Furthermore, the antibacterial efficacy by the technique of disc diffusion exhibited clear inhibition zones in ZnO NPs-treated discs. In addition, 125µg/mL of ZnO NP concentration showed minimum inhibition by the microbroth dilution method. The potent inhibitory activity was further validated with trypan blue dye exclusion and fluorescence microscopy. Finally, SEM examination confirmed the efficient antibacterial potential of ZnO NPs through disruption of the intact morphology of Klebsiella pneumoniae.

Epitaxial Growth of Two-Dimensional MWW Zeolite.

Two-dimensional (2D) zeolite, with a high aspect ratio, has more open skeletons and accessible active sites than its three-dimensional (3D) counterpart. However, traditional methods of obtaining 2D zeolites often cause structural damage and widespread skeleton defects, hindering efficient selectivity in molecular separation. In this study, we present, for the first time, a direct epitaxial synthesis of 2D zeolite (Epi-MWW) guided by hexagonal boron nitride (h-BN) with a coincidence matching of site lattices to MWW zeolite. The as-grown Epi-MWW zeolite possesses a high crystallinity and intact hexagonal 2D morphology, with an average thickness of 10 nm and an aspect ratio of over 50. Thanks to its excellent molecular accessibility, the diffusion time constants of o-xylene (OX) and p-xylene (PX) are as 12 and 133 times higher than those of conventional MCM-22, respectively; the PX/OX selectivity of Epi-MWW is 7.4 times better than MCM-22 as calculated by the ideal adsorbed solution theory.

Facile encapsulation of cyanoacrylate-based bioadhesive by electrospray method and investigation of the process parameters

Polymer microcapsules containing cyanoacrylates have represented a promising option to develop self-healing biomaterials. This study aims to develop an electrospray method for the preparation of capsules using poly(methyl methacrylate) (PMMA) as the encapsulant and ethyl 2-cyanoacrylate (EC) as the encapsulate. It also aims to study the effect of the electrospray process parameters on the size and morphology of the capsules. The capsules were characterized using Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field-emission scanning electron microscopy (FE-SEM). Moreover, the effects of electrospray process parameters on the size were investigated by Taguchi experimental design. FTIR and TGA approved the presence of both PMMA and EC without further reaction. FE-SEM micrograph demonstrated that an appropriate choice of solvents, utilizing an appropriate PMMA:EC ratio and sufficient PMMA concentration are critical factors to produce capsules dominantly with an intact and spherical morphology. Utilizing various flow rates (0.3–0.5 ml/h) and applied voltage (18–26 kV), capsules were obtained with a 600–1000 nm size range. At constantly applied voltages, the increase in flow rate increased the capsule size up to 40% (ANOVA, p ≤ 0.05), while at constant flow rates, the increase in applied voltage reduced the average capsule size by 3.4–26% (ANOVA, p ≤ 0.05). The results from the Taguchi design represented the significance of solution flow rate, applied voltage, and solution concentration. It was shown that the most effective parameter on the size of capsules is flow rate. This research demonstrated that electrospray can be utilized as a convenient method for the preparation of sub-micron PMMA capsules containing EC. Furthermore, the morphology of the capsules is dominated by solvents, PMMA concentration, and PMMA:EC ratio, while the average size of the capsules can be altered by adjusting the flow rate and applied voltage of the electrospray process.

Quantitative fetal MRI with diffusion tensor imaging in cases with 'short' corpus callosum.

It has been suggested previously that the presence of Probst bundles (PB) in cases with a short corpus callosum (SCC) on diffusion tensor imaging (DTI) may help to differentiate between corpus callosal (CC) dysplasia and a variant of normal CC development. The objectives of this study were to compare DTI parameters between cases of SCC vs normal CC and between cases of SCC with PB (SCC-PB+) vs SCC without PB (SCC-PB-). This was a retrospective study of patients referred to the Necker Hospital in Paris, France, for magnetic resonance imaging (MRI) evaluation of an apparently isolated SCC detected by sonography between November 2016 and December 2022 (IRB: 00011928). MRI was performed using a 1.5-Tesla Signa system. T2-weighted axial and sagittal sequences of the fetal brain were used to measure the length and thickness of the CC. 16-direction DTI axial brain sequences were performed to identify the presence of PB and to generate quantitative imaging parameters (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)) of the entire CC, genu, body and splenium. Cases in which other associated brain abnormalities were detected on MRI were excluded. Cases were matched for fetal gender and gestational age with controls in a 1:3 ratio. Control cases were normal fetuses included in the LUMIERE on the FETUS trial (NCT04142606) that underwent the same DTI evaluation of the brain. Comparisons between SCC and normal CC cases, and between SCC-PB+ and SCC-PB- cases were performed using ANOVA and adjusted for potential confounders using ANCOVA. Twenty-two SCC cases were included and compared with 66 fetuses with a normal CC. In 10/22 (45.5%) cases of SCC, PB were identified. As expected, dimensions of the CC were significantly smaller in SCC compared with normal CC cases (all P < 0.01). In SCC-PB+ vs SCC-PB- cases, FA values were significantly lower in the entire CC (median, 0.21 (range, 0.19-0.24) vs 0.24 (range, 0.22-0.28); P < 0.01), genu (median, 0.21 (range, 0.15-0.29) vs 0.24 (range, 0.17-0.29); P = 0.04), body (median, 0.21 (range, 0.18-0.23) vs 0.23 (range, 0.21-0.27); P = 0.04) and splenium (median, 0.22 (range, 0.16-0.30) vs 0.25 (range, 0.20-0.29); P = 0.03). ADC values were significantly higher in the entire CC, genu and body in SCC-PB+ vs SCC-PB- cases (all P < 0.05). In SCC-PB+ cases, all FA values were significantly lower, and ADC values in the CC body were significantly higher compared with normal CC cases (all P < 0.05). In SCC-PB- cases, there was no significant difference in FA and ADC compared with normal CC cases (all P > 0.05). Fetal DTI evaluation of the CC showed that FA values were significantly lower and ADC values tended to be significantly higher in SCC-PB+ compared with normal CC cases. This may highlight alterations of the white matter microstructure in SCC-PB+. In contrast, isolated SCC-PB- did not demonstrate significant changes in DTI parameters, strengthening the possibility that this is a normal CC variant. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Self-Assembled Monolayers of a Fluorinated Phosphonic Acid as a Protective Coating on Aluminum

Aluminum (Al) placed in hot water (HW) at 90 °C is roughened due to its reaction with water, forming Al hydroxide and Al oxide, as well as releasing hydrogen gas. The roughened surface is thus hydrophilic and possesses a hugely increased surface area, which can be useful in applications requiring hydrophilicity and increased surface area, such as atmospheric moisture harvesting. On the other hand, when using HW to roughen specified areas of an Al substrate, ways to protect the other areas from HW attacks are necessary. We demonstrated that self-assembled monolayers (SAMs) of a fluorinated phosphonic acid (FPA, CF3(CF2)13(CH2)2P(=O)(OH)2) derivatized on the native oxide of an Al film protected the underneath metal substrate from HW attack. The intact wettability and surface morphology of FPA-derivatized Al subjected to HW treatment were examined using contact angle measurement, and scanning electron microscopy and atomic force microscopy, respectively. Moreover, the surface and interface chemistry of FPA-derivatized Al before and after HW treatment were investigated by time-of-flight secondary ion mass spectrometry (ToF-SIMS), verifying that the FPA SAMs were intact upon HW treatment. The ToF-SIMS results therefore explained, on the molecular level, why HW treatment did not affect the underneath Al at all. FPA derivatization is thus expected to be developed as a patterning method for the formation of hydrophilic and hydrophobic areas on Al when combined with HW treatment.

Molecular structure regulation of functional polylactic acid based on chain expansion reaction and its improved hydrolysis resistance

AbstractIn this work, the functional polylactic acid (PLA) was synthesized using epoxy chain extender (ADR) as a chain extender agent through melt blending method. The effects of ADR content on the molecular structure, thermal properties, and tensile properties of the functional PLA were investigated. Meanwhile, the hydrolytic behavior of the PLA/ADR materials at different hydrolysis temperatures was explored. It was found that ADR effectively regulated the molecular structure of PLA in the molten state and significantly increased the relative molecular weight, storage modulus, and complex viscosity of PLA. In addition, the Cole‐Cole diagram results suggested the branched structure of PLA chain expansion systems. Based on mechanical property tests, it was noted that the addition of ADR made the molecular chain form a micro‐crosslinked structure. Additionally, the mass loss rate of PLA/1.6ADR (the dosage of ADR was 1.6 wt%) was 14.75% after 14 weeks of hydrolysis under hydrolysis conditions at 58°C, while that of pure PLA was 25.89%. Moreover, the functional PLA/ADR materials exhibited significantly slower decrease rates in molecular weight, melting temperature, and tensile strength, and still maintained intact morphology after 14 weeks of hydrolysis compared to pure PLA. Therefore, the molecular structure of PLA is effectively regulated by ADR, which greatly enhances the hydrolysis resistance and further promotes the range of application of PLA.

Isotropic sintering shrinkage of 3D glass-ceramic nanolattices: backbone preforming and mechanical enhancement

There is a perpetual pursuit for free-form glasses and ceramics featuring outstanding mechanical properties as well as chemical and thermal resistance. It is a promising idea to shape inorganic materials in three-dimensional (3D) forms to reduce their weight while maintaining high mechanical properties. A popular strategy for the preparation of 3D inorganic materials is to mold the organic–inorganic hybrid photoresists into 3D micro- and nano-structures and remove the organic components by subsequent sintering. However, due to the discrete arrangement of inorganic components in the organic-inorganic hybrid photoresists, it remains a huge challenge to attain isotropic shrinkage during sintering. Herein, we demonstrate the isotropic sintering shrinkage by forming the consecutive –Si–O–Si–O–Zr–O– inorganic backbone in photoresists and fabricating 3D glass–ceramic nanolattices with enhanced mechanical properties. The femtosecond (fs) laser is used in two-photon polymerization (TPP) to fabricate 3D green body structures. After subsequent sintering at 1000 °C, high-quality 3D glass–ceramic microstructures can be obtained with perfectly intact and smooth morphology. In-suit compression experiments and finite-element simulations reveal that octahedral-truss (oct-truss) lattices possess remarkable adeptness in bearing stress concentration and maintain the structural integrity to resist rod bending, indicating that this structure is a candidate for preparing lightweight and high stiffness glass–ceramic nanolattices. 3D printing of such glasses and ceramics has significant implications in a number of industrial applications, including metamaterials, microelectromechanical systems, photonic crystals, and damage-tolerant lightweight materials.

Comparative Evaluation of Penetration of Two Irrigating Solutions into Dentinal Tubules Using Diode Laser and Ultrasonic Activation: A Confocal Laser Microscopy Study Protocol

Introduction: Endodontic therapy aims to eradicate pulpal and periapical diseases by removing bacteria from root canals. Despite thorough cleaning, the smear layer obstructs canal disinfection. Root canal preparation and irrigation, particularly with sodium hypochlorite, are essential for debridement. However, conventional techniques may leave areas untreated, necessitating innovative solutions like superoxidised water and Laser-activated Irrigation (LAI) for effective treatment. Need for the Study: The effectiveness of root canal treatment is contingent upon the success of the irrigating solution and the mode used for its activation, which is directly reflected in its ability to penetrate dentinal tubules. Thus, the focus of this experimental in-vitro study is to identify the most suitable irrigating solution and an effective activation technique for better penetration into dentinal tubules. Aim: The study will evaluate and compare the penetration of Sodium Hypochlorite (NaOCl) and oxidised water irrigants into dentinal tubules using diode laser and ultrasonic activation. Materials and Methods: An experimental in-vitro study will be conducted in the Department of Conservative Dentistry and Endodontics at Sharad Pawar Dental College and Hospital, Wardha, Maharashtra, India, from August 2024 to May 2025. The approach involves categorising 60 recently extracted single-rooted teeth with fully formed apical foramina and intact occlusal morphology into six primary groups according to distinct irrigation techniques and the application of two different irrigants, resulting in 10 teeth per group. Decoronated specimens will be injected with a specific irrigant and activated using different techniques. The penetration of oxidised water into dentinal tubules by low-level laser therapy and ultrasonic activation will be evaluated and compared using confocal laser microscopy. The normality of the data will be analysed using the Kolmogorov-Smirnov test. If the data are normal, then the T-Analysis of Variance (ANOVA) test will be applied; if not, the Kruskal-Wallis test will be used at a 5% level of significance (p≤0.05).

Potential of asiaticoside encapsulated alginate chitosan nanoparticles in the management of antiproliferative activity in C6 glioma cells

BackgroundAsiaticoside is a pentacyclic triterpenoid saponin constituent of the medicinal herb Centella asiatica, known for its neuroprotective, anticancer and other biological effects. The present study aims to develop and characterise asiaticoside encapsulated alginate chitosan nanoparticles (ACNPs) and evaluate their antiproliferative potential on C6 glioma cells. MethodsACNPs were prepared by the ionic gelation polyelectrolyte complexation technique and characterised by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. Cytotoxicity and antiproliferative effect of ACNPs were studied on C6 glioma cells using MTT and EdU-assays. Apoptosis/necrosis in C6 glioma cells was determined by annexin V and acridine orange/ethidium bromide (AO/EtBr) assays. Intracellular ROS generation in C6 glioma cells exposed with ACNP was determined by DCFDA assay using flow cytometry. Cell cycle analysis in C6 glioma cells treated with ACNP was performed by flow cytometry. ResultsSynthesised ACNPs showed spherical shape with 200 nm particle size, good thermal stability, and an acceptable polydispersity index. ASI from synthesized ACNPs demonstrated 90% encapsulation efficiency (EE) and 10% drug release within 24 h. Upon ACNP treatment mBA cells exhibited good cell viability and intact cell morphology. However, C6 cells displayed dose-dependent cytotoxicity when treated with ACNP. Annexin V and acridine orange/ethidium bromide (AO/EtBr) assays revealed late apoptosis and necrosis (p < 0.05) in C6 glioma cells treated with ACNP. Likewise, ACNPs significantly augmented reactive oxygen species generation (p < 0.05) in C6 glioma cells. ACNP treatment also resulted in cell cycle arrest at the G1 phase with chromatin condensation in C6 glioma cells. ConclusionsThese findings suggest that ACNPs act as an antiproliferative agent against C6 glioma cells via an increased intracellular ROS pathway that promotes apoptosis/necrosis. This study throws light on more in-depth mechanistic aspects of managing brain disorders using C. asiatica and its phytoconstituents.

A 4D printed nanoengineered super bioactive hydrogel scaffold with programmable deformation for potential bifurcated vascular channel construction.

Four-dimensional (4D) printing of hydrogels enabled the fabrication of complex scaffold geometries out of static parts. Although current 4D fabrication strategies are promising for creating vascular parts such as tubes, developing branched networks or tubular junctions is still challenging. Here, for the first time, a 4D printing approach is employed to fabricate T-shaped perfusable bifurcation using an extrusion-based multi-material 3D printing process. An alginate/methylcellulose-based dual-component hydrogel system (with defined swelling behavior) is nanoengineered with carbonized alginate (∼100 nm) to introduce anti-oxidative, anti-inflammatory, and anti-thrombotic properties and shape-shifting properties. A computational model to predict shape deformations in the printed hydrogels with defined infill angles was designed and further validated experimentally. Shape deformations of the 3D-printed flat sheets were achieved by ionic cross-linking. An undisrupted perfusion of a dye solution through a T-junction with minimal leakage mimicking blood flow through vessels is also demonstrated. Moreover, human umbilical vein endothelial and fibroblast cells seeded with printed constructs show intact morphology and excellent cell viability. Overall, the developed strategy paves the way for manufacturing self-actuated vascular bifurcations with remarkable anti-thrombotic properties to potentially treat coronary artery diseases.

A new method for isolation and purification of fusion-competent inhibitory synaptic vesicles

Synaptic vesicles specific to inhibitory GABA-releasing neurons are critical for regulating neuronal excitability. To study the specific molecular composition, architecture, and function of inhibitory synaptic vesicles, we have developed a new method to isolate and purify GABA synaptic vesicles from mouse brains. GABA synaptic vesicles were immunoisolated from mouse brain tissue using an engineered fragment antigen-binding region (Fab) against the vesicular GABA transporter (vGAT) and purified. Western blot analysis confirmed that the GABA synaptic vesicles were specifically enriched for vGAT and largely depleted of contaminants from other synaptic vesicle types, such as vesicular glutamate transporter (vGLUT1), and other cellular organelles. This degree of purity was achieved despite the relatively low abundance of vGAT vesicles compared to the total synaptic vesicle pool in mammalian brains. Cryo-electron microscopy images of these isolated GABA synaptic vesicles revealed intact morphology with circular shape and protruding proteinaceous densities. The GABA synaptic vesicles are functional, as assessed by a hybrid (ex vivo/in vitro) vesicle fusion assay, and they undergo synchronized fusion with synthetic plasma membrane mimic vesicles in response to Ca2+-triggering, but, as a negative control, not to Mg2+-triggering. Our immunoisolation method could also be applied to other types of vesicles.

High-moisture extrusion of curdlan: Texture and structure

High-moisture extrusion is a promising thermomechanical technology extensively employed in manufacturing fibrous meat analogues from plant-based proteins, garnering considerable research attention. However, polysaccharide-based extrusion has been rarely explored. The present study investigates the effects of varying extruder barrel temperatures (130 °C–200 °C) on the texture and structure of curdlan extrudates, and highlights the formation mechanism. Results showed that the single chain of curdlan aggregates to form triple-helix chains upon extrusion, consequently enhancing the crystallinity, particularly at 170 °C. The hardness, chewiness, and mechanical properties improved with increasing barrel temperature. Moreover, barrel temperatures affected the macrostructure, the extrudates maintained intact morphologies except at 160 °C due to the melting of curdlan gel as confirmed by the differential scanning calorimetry thermogram. Microstructural analysis revealed that curdlan extrudates transited through three phases: original gel (130 °C, 140 °C, and 150 °C), transition state (160 °C), and regenerated gel (170 °C, 180 °C, 190 °C, and 200 °C). The steady state of regenerated gel (170 °C) exhibited higher crystallinity and smaller fractal dimension, resulting in a more compact and crosslinked gel network. This study elucidates the structure transition of curdlan gel at extremely high temperatures, offering valuable technical insights for developing theories and methods with respect to polysaccharide-based extrusion that may find applications in food-related fields.

MOF-derived Al3+-doped Co3O4 nanocomposites for highly n-butanol gas sensing performance at low operating temperature

High-performance gas sensors based on metal oxides for detecting Volatile Organic Compounds (VOCs) at low operating temperatures have garnered considerable attention due to their practical utility and energy efficiency. In this study, we synthesized the Al/Co metal-organic framework (MOF) by using a hydrothermal method. Subsequently, Al3+-doped Co3O4 (Al3+-Co3O4) nanocomposites with varying Al3+ concentrations were obtained through calcination. When applied to gas sensors, the Al3+-Co3O4 nanocomposites-based gas sensors exhibited excellent sensing properties toward n-butanol at a low operating temperature (100 ℃). Specifically, the response of the 10% Al3+-Co3O4 nanocomposite to 20 ppm n-butanol reached 116.7, representing an approximately 5.5-fold improvement compared to pristine Co3O4. The gas sensor based on the 10% Al3+-Co3O4 nanocomposite also demonstrated commendable repeatability, selectivity, and stability. This suggests that Al3+ doping results in Al3+-Co3O4 possessing a more intact spherical morphology. Doping significantly enhances the gas-sensing performance of Al3+-Co3O4 due to increased oxygen vacancies and a narrower band gap energy. These findings inspire the development of new p-type metal oxide semiconductor gas sensors operating at low temperatures.

Preparation and properties of PEEK-g-PNIPAm separation membranes with thermo-responsiveness for emulsion and organic liquid separation

Although poly (ether ether ketone) (PEEK) exhibits excellent solvent resistance, it could not be prepared directly by non-solvent induced phase separation (NIPS) method due to its poor solubility. Herein, PEEK porous membranes were successfully fabricated by combining NIPS and acid hydrolysis. The superhydrophilic thermo-responsive poly (N-isopropylacrylamide) (PNIPAm) polymer was in-situ grafted on the PEEK membrane surface via the UV grafting polymerization and improved the membrane interface hydrophilicity, making the membrane water contact angle changed from 89.5° to 0° at 25 °C. After heating the membrane surface to 40 °C, the membrane exhibited hydrophobicity (100°), realizing the thermo-responsiveness via switching the temperature. Furthermore, due to the transferred membrane wettability at different temperatures, PEEK-g-PNIPAm could separate different types of oil-bearing systems with high rejection above 99.0 %. What’s more, the PNIPAm layer also enhanced the membrane anti-fouling capacity. Benefiting from the extraordinary solvent resistance of the PEEK matrix, PEEK-g-PNIPAm maintains its intact morphology after 6 h immersion in various organic solvents, addressing the commonly reported problem of polymer membranes having certain solubility in solvents. The PEEK-based membranes with excellent solvent resistance could be useful in the oil-bearing separation.

Facial synthesis of Cu@Ag core-shell particles through temperature gradient method with excellent oxidation resistance

To improve the oxidation resistance of Cu particles, the temperature gradient method is used to prepare Cu@Ag core-shell particles (TG-Cu@AgCSPs) with uniform particle size and enhanced oxidation resistance. The TG-Cu@AgCSPs are spherical, with an average size of 2.9 [Formula: see text] m, and the average thickness of the Ag shells is 280 nm. The morphological analysis and thermogravimetric results show that the TG-Cu@AgCSPs possess denser Ag shells and better oxidation resistance compared to core-shell particles prepared by the thermostatic method. The thermal oxidation behavior of TG-Cu@AgCSPs is investigated by heating in air. When heated below 300[Formula: see text]C, the Ag shells can keep intact morphology and protect the Cu cores from oxidation. Whereas the original Cu particles will be oxidized at 150[Formula: see text]C. In addition, the TG-Cu@AgCSPs are prepared as low-temperature conductive pastes to investigate their electrical properties. Compared with commercial Cu@Ag core-shell particles, the TG-Cu@AgCSPs possess more outstanding performance advantages and have the potential for commercial applications.

Spider Silk-Inspired Binder Design for Flexible Lithium-Ion Battery with High Durability.

The development of flexible lithium-ion batteries (LIBs) imposes demands on energy density and high mechanical durability simultaneously. Due to the limited deformability of electrodes, as well as the flat and smooth surface of the metal current collectors, stable/durable/reliable contact between electrode materials and the current collectors remains a challenge, in particular, for electrodes with high loading mass and heavily deformed batteries. Binders play an essential role in binding particles of electrode materials and adhering them to current collectors. Herein, inspired by spider silk, a binder for flexible LIBs is developed, which equips a cross-linked supramolecular poly(urethane-urea) to the polyacrylic acid. The binder imparts super high elastic restorability originating from the meticulously engineered hydrogen-bonding segments as well as extraordinary adhesion. The developed binder provides excellent flexibility and intact electrode morphologies without disintegration even when the electrode is largely deformed, enabling a stable cycling and voltage output even when the batteries are put under tough dynamic deformation tests. The flexible LIBs exhibit a high energy density of 420WhL-1 , which is remarkably higher than reported numbers. The unique binder design is greatly promising and offers a valuable material solution for LIBs with high-loading mass and flexible designs.

Oxygen enrichment protects against intestinal damage and gut microbiota disturbance in rats exposed to acute high-altitude hypoxia.

Acute high-altitude hypoxia can lead to intestinal damage and changes in gut microbiota. Sustained and reliable oxygen enrichment can resist hypoxic damage at high altitude to a certain extent. However, it remains unclear whether oxygen enrichment can protect against gut damage and changes in intestinal flora caused by acute altitude hypoxia. For this study, eighteen male Sprague-Dawley rats were divided into three groups, control (NN), hypobaric hypoxic (HH), and oxygen-enriched (HO). The NN group was raised under normobaric normoxia, whereas the HH group was placed in a hypobaric hypoxic chamber simulating 7,000 m for 3 days. The HO group was exposed to oxygen-enriched air in the same hypobaric hypoxic chamber as the HH group for 12 h daily. Our findings indicate that an acute HH environment caused a fracture of the crypt structure, loss of epithelial cells, and reduction in goblet cells. Additionally, the structure and diversity of bacteria decreased in richness and evenness. The species composition at Phylum and Genus level was characterized by a higher ratio of Firmicutes and Bacteroides and an increased abundance of Lactobacillus with the abundance of Prevotellaceae_NK3B31_group decreased in the HH group. Interestingly, after oxygen enrichment intervention, the intestinal injury was significantly restrained. This was confirmed by an increase in the crypt depth, intact epithelial cell morphology, increased relative density of goblet cells, and higher evenness and richness of the gut microbiota, Bacteroidetes and Prevotellaceae as the main microbiota in the HO group. Finally, functional analysis showed significant differences between the different groups with respect to different metabolic pathways, including Amino acid metabolism, energy metabolism, and metabolism. In conclusion, this study verifies, for the first time, the positive effects of oxygen enrichment on gut structure and microbiota in animals experiencing acute hypobaric hypoxia.

Improving the physicochemical stability and release properties of curcumin using κ-carrageenan/scallop hydrolysates hydrogel beads

Scallop (Patinopecten yessoensis) male gonad hydrolysates (SMGHs)/κ-carrageenan (KC)/KCl beads with SMGHs:KC ratios (0:10–5:5) were investigated. SMGHs/KC/KCl-Cur bead (5:5) exhibited the most intact spherical morphology and highest Cur loading content of 0.063 mg/0.1 g bead, ascribing to a shortened T23 from 1607.9 to 966.4 ms, and red and blueshifts of OH, NH, amide I and II bands. The undetected fingerprint region within 7.82°-28.90° of SMGHs/KC/KCl-Cur beads indicated successful Cur entrapment. Moreover, SMGHs/KC/KCl-Cur beads exhibited shrinkage network backbones and larger void pores as SMGHs increased, with vessel percentage area, total number of junctions, total vessel length decreasing from 52.1, 1446.8, 57931.4 to 39.7, 530.5, 34458.4, and lacunarity increasing from 0.048 to 0.111, respectively. Furthermore, Cur showed approximately 50% release contents in colon phase and above 90% retention rate during 30 days of storage at 4 °C. These results suggested that SMGHs/KC/KCl-Cur beads exhibited sustained-release of Cur and promised stable Cur preservation.

Impact of amylose content on the formation of V-type granular starch

V-type granular starch (VGS) was prepared by aqueous-ethanol heat treatment using normal maize starch (NMS) with an amylose content of 31.02% (NMS1), 25.08% (NMS2), or 22.39% (NMS3). The effects of different amylose contents on VGS granular morphology, crystalline structure, thermal transitions, and cold-water paste viscosity properties were compared. Moreover, the effects of different temperature holding times (0–30 min) during aqueous-ethanol heat treatment on the formation of VGS were evaluated. The results showed that NMS1, for which the amylose content was the highest, required 5 min holding at 100 °C to reach the maximum V-type relative crystallinity (13.97%) and the highest cold-water paste viscosity (2981.28 cP) while maintaining the most intact granular morphology. Longer temperature holding periods caused damage to starch granules and decreased the formation of V-type crystals. Higher amylose content was beneficial for preservation of starch granule integrity and the formation of V-type crystals, resulting in a higher cold-water paste viscosity of VGS. However, starch with higher amylose contents required more energy to fully disorder amylose to form V-type complexes with ethanol.

Effect and mechanism of Puerariae Lobatae Radix in alleviating insulin resistance in T2DM db/db mice based on intestinal flora

This study aimed to examine the effect and underlying mechanism of Puerariae Lobatae Radix on insulin resistance in db/db mice with type 2 diabetes mellitus(T2DM) based on the analysis of intestinal flora. Fifty db/db mice were randomly divided into a model group(M group), a metformin group(YX group), a high-dose Puerariae Lobatae Radix group(YGG group), a medium-dose Puerariae Lobatae Radix group(YGZ group), and a low-dose Puerariae Lobatae Radix group(YGD group). Another 10 db/m mice were assigned to the normal group(K group). After continuous administration for eight weeks, body weight and blood sugar of mice were measured. Enzyme linked immunosorbent assay(ELISA) was used to detect glycosylated serum protein(GSP) and fasting serum insulin(FINS), and insulin resistance index(HOMA-IR) was calculated. The histopathological changes in the pancreas were observed by HE staining. Tumor necrosis factor(TNF)-α expression in the pancreas was detected using immunohistochemistry. The structural changes in fecal intestinal flora in the K, M, and YGZ groups were detected by 16S rRNA. Western blot was used to detect the expression of farnesoid X receptor(FXR) and takeda G protein-coupled receptor 5(TGR5) in the ileum, cholesterol 7α-hydroxylase(CYP7A1) and sterol 27α-hydroxylase(CYP27A1) in the liver, and G protein-coupled receptors 41(GPR41) and 43(GPR43) in the colon. Compared with the K group, the M group showed increased body weight, blood sugar, serum GSP, fasting blood glucose(FBG), and FINS, increased HOMA-IR, inflammatory infiltration of islet cells, necrosis and degeneration of massive acinar cells, unclear boundary between islet cells and acinar cells, disturbed intestinal flora, and down-regulated FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43. Compared with the M group, the YX, YGG, YGZ, and YGD groups showed decreased body weight, blood sugar, serum GSP, FBG, and FINS, islet cells with intact and clumpy morphology and clear boundary, necrosis of a few acinar cells, and more visible islet cells. The intestinal flora in the YGZ group changed from phylum to genus levels, and the relative abundance of intestinal flora affecting the metabolites of intestinal flora increased. The protein expression of FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43 increased. The results show that Puerariae Lobatae Radix can improve the inflammatory damage of pancreatic islet cells and reduce insulin resistance in db/db mice with T2DM. The mechanism of action may be related to the increase in the abundance of Actinobacteria, Bifidobacterium, and Bacteroides in the intestinal tract and the protein expression related to metabolites of intestinal flora.