Lamellar Layers Research Articles

Membrane progesterone receptor γ (paqr5b) is essential for the formation of neurons in the zebrafish olfactory rosette

Paqr5b is a gene encoding membrane progesterone receptor γ (mPRγ), which is one of five mPR subtypes. Paqr5b belongs to the progestin and adipoQ receptor (PAQR) family, which consists of 11 genes. To elucidate the physiological functions of the mPR subtypes, we established gene knockout (KO) zebrafish strains by genetically editing seven paqr genes and analyzed their phenotypes. The null-mutant strain of paqr5b (paqr5b−/−) that we established in this study showed low fecundity, reduced chorion elevation and a high percentage of abnormal embryos. Embryos showed curvature of the spine and an abnormal head morphology. Individuals with abnormal head morphology continued to develop a phenotype of markedly abnormal palatine bone. The length of the brain of paqr5b−/− zebrafish was short, and the position of the cerebellum moved to the front and overlapped with that of the midbrain. Micro-CT scans revealed that the olfactory rosettes (ORs) were so shrunken that they were difficult to identify and connected with the olfactory bulbs (OBs) by thread-like structures. Immunohistochemical staining of OR with an anti-Paqr5b antibody revealed that Paqr5b was extensively expressed in neurons in the OR in wild-type zebrafish, whereas signals were not detected in paqr5b−/− zebrafish. In histological sections, the neurons disappeared, and the lamellar layer of the OR became thinner. These results indicate that Paqr5b is required for the formation of neurons in the OR. This is the first report demonstrating a distinct role for the mPR gene.

Comparative study of corrosion behaviors of SS310 stainless steel in NaCl-KCl-MgCl2 and NaCl-KCl-CaCl2 molten salts

Concentrated solar power plants using chloride molten salt as heat transfer fluids imply high corrosion risks. The corrosion behaviour of SS310 stainless steel in NaCl-KCl-MgCl2 and NaCl-KCl-CaCl2 molten salts was comparatively studied. MgCl2 exhibits remarkably higher hygroscopicity than CaCl2, inducing a significant difference in the concentration of HCl that directly results in the matrix corrosion. The hydrolysis of MgCl2 produces large amounts of MgO that destroys Cr2O3 film and produce less-protective MgCr2O4. Correspondingly, a heterogeneous oxide bilayer is formed in NaCl-KCl-MgCl2. In NaCl-KCl-CaCl2, a lamellar oxide layer composed of primarily Ni(Fe,Cr)2O4 can effectively block the corrosive species H2O and HCl.

Biomimetic structural aerogel derived from green tide enteromorpha-prolifera: Multi-sided unidirectional freeze casting and solar-driven viscous oil spill remediation

The development of environmental remediation materials from renewable biowaste, especially for the cleanup of viscous oil spills in an eco-friendly manner, marks a substantial advancement in functional materials. This study proposes a biomass aerogel (M−MCEP) transformed from Enteromorpha prolifera (EP) in green tides for solar-driven recovery of high-viscosity oil spills. Inspired by the lamella-bridge architecture of Thalia dealbata stems, a biomimetic structure with multi-domain, long-range aligned lamella-bridge interconnections is constructed by a multi-sided unidirectional freeze-casting technique. Multi-scale interface optimization between rigid photothermal fillers and soft lamellar layers achieves multiple reinforcements, providing aerogel with a perfect balance of elasticity and strength. The multidomain low tortuosity channels and photothermal effects enhance M−MCEP’s photothermal conversion (95.2 %) and thermal conductivity (0.3517 W/m·K), reducing oil flow resistance and achieving high oil retention efficiency (>92 %). Under 1 sun irradiation, M−MCEP rapidly heats to 67.3 °C, effectively reducing the viscosity of crude oil in situ, with a crude oil adsorption rate of 1843 mL/m2 within 30 s. Moreover, M−MCEP captures emulsified oil in oil-in-water emulsions through high-speed repeated oscillations, achieving a separation efficiency of 96.42–99.21 %. Renewable resources and unique structural designs provided by nature drive the development of advanced biomimetic aerogels for efficiently remedying catastrophic oil spills.

Ultrahigh-strength cellulose nanofiber foams via the synergy of freeze-casting and solvent exchange

Ultrahigh-strength and lightweight materials have found wide use. However, it is difficult for artificial materials to maintain high strength while being lightweight, as the mechanical properties of most materials are strongly dependent on density. In this study, we combined the methods of freeze casting and solvent exchange to prepare cellulose nanofiber foams with lightweight and ultrahigh strength. Freeze casting created the continuous 3D network at the microscale while solvent exchange promoted the reconstruction of cellulose nanofibers via the alkali-induced mercerization effect. The foams thus possessed an ordered hierarchical structure that contained lamellar layers at the microscale and a high density of pores at the nanoscale. A quadratic exponential positive correlation between relative modulus and relative density was identified for the foams. The maximum compressive and bending moduli of the foams were 26.09 and 42.10 MPa, respectively, while its density was 210.16 mg/cm3. The study provides a robust method for the preparation of lightweight and high-strength cellulose foams.

Construction of tree-ring mimetic 3D networks in polyvinyl alcohol/boron nitride composites for enhanced thermal management and mechanical properties

Constructing a three-dimensional (3D) filler network in polymer thermal interface materials (TIMs) is crucial for enhancing thermal conductivity and mechanical properties. However, the discontinuous and loose network of fillers are one of the main reasons hindering the joint improvement of thermal conductivity and mechanical properties. The construction of a regular and dense 3D continuous filler network remains a significant challenge. In this study, an innovative bidirectional freezing technique was designed to create a polyvinyl alcohol (PVA)/boron nitride (BN) composite with a tree-ring-like 3D network. This technique promotes the formation of 3D network consisting of long-range lamellar BN layers with a tree-ring-like structure by controlling the nucleation and growth of ice crystals along the bidirectional temperature gradient induced by a polytetrafluoroethylene (PTFE) cone. The resulting PVA/BN composite exhibits high thermal conductivity (6.25 W/m·K) due to the lower interfacial thermal resistance between fillers (1.271 × 10−7 K m2/W), and an enhanced tensile strength of 41.71 MPa, which is attributed to the regular and dense BN network. This study presents a feasible strategy for constructing a 3D continuous network structure in polymer-based TIMs, paving the way for advancements in thermal management solutions.

Cellulose Nanofiber-Based Nanocomposite Films with Efficient Electromagnetic Interference Shielding and Fire-Resistant Performance.

Cellulose nanofiber (CNF) has been widely used as a flexible and lightweight polymer matrix for electromagnetic shielding and thermally conductive composite films because of its excellent mechanical strength, environmental performance, and low cost. However, the lack of flame retardancy seriously hinders its further application. Herein, renewable and biomass-sourced l-arginine (AR) was used to surface-modify ammonium polyphosphate (APP) and an environmentally friendly biobased flame retardant was synthesized by the coordination of zinc sulfate heptahydrate (ZnSO4·7H2O), which was named AAZ. AAZ was deposited on the surface of CNF by electrostatic adsorption and Zn2+ complexation. The biobased compatibilizer Triton X-100 was employed to assist the exfoliation of graphene nanoplatelets (GNPs) and their dispersion in the CNF matrix. Due to the formation of a dense lamellar layer resembling a shell structure, the CNF/GNPs composite films with a tensile strength of 52 MPa were obtained via vacuum-assisted filtration. Because the phosphorus-containing group produces a protective layer of PxOy compound and promotes the formation of a carbon layer by CNF and the combustion releases ammonia gas, the fire-resistant performance of the composite films was greatly improved. Compared with the pure CNF film, the composite film exhibits 33% reduction in PHRR value and 40% reduction in THR. In addition, the CNF/GNPs composite film with 20 wt % GNPs possessed high conductivity (2079.2 S/m) and electromagnetic interference (EMI) shielding effectiveness (37 dB). The ultrathin CNF/GNPs composite films have excellent potential for use as efficient flame retardant and EMI shielding materials.

One-step solvothermal synthesis of Zn2SnO4/rGO composite material and highly gas sensing performance to acetone

In this study, one-step solvothermal method was employed to synthesize Zn2SnO4 and Zn2SnO4/rGO composites. Zn2SnO4 was bonded to the rGO surface or in the spaces between the lamellar layers to create a semiconductor composite material that is physically supported by heterojunction. Compared to Zn2SnO4 sensor, the Zn2SnO4/rGO sensing material exhibits superior gas-sensing properties to acetone. The optimal temperature of Zn2SnO4/rGO sensor was just 200 °C, while its sensitivity to 100 ppm acetone gas was up to 11.2. Its response and recovery times were only 8 s and 11 s, respectively. The large specific surface area and distinctive heterojunction of the composite material are responsible for the enhanced gas-sensing performance of Zn2SnO4/rGO sensing material. Zn2SnO4/rGO is an ideal sensing material due to high sensitivity, fast response/recovery properties, great selectivity, and stability.

Focus on seed cells: stem cells in 3D bioprinting of corneal grafts.

Corneal opacity is one of the leading causes of severe vision impairment. Corneal transplantation is the dominant therapy for irreversible corneal blindness. However, there is a worldwide shortage of donor grafts and consequently an urgent demand for alternatives. Three-dimensional (3D) bioprinting is an innovative additive manufacturing technology for high-resolution distribution of bioink to construct human tissues. The technology has shown great promise in the field of bone, cartilage and skin tissue construction. 3D bioprinting allows precise structural construction and functional cell printing, which makes it possible to print personalized full-thickness or lamellar corneal layers. Seed cells play an important role in producing corneal biological functions. And stem cells are potential seed cells for corneal tissue construction. In this review, the basic anatomy and physiology of the natural human cornea and the grafts for keratoplasties are introduced. Then, the applications of 3D bioprinting techniques and bioinks for corneal tissue construction and their interaction with seed cells are reviewed, and both the application and promising future of stem cells in corneal tissue engineering is discussed. Finally, the development trends requirements and challenges of using stem cells as seed cells in corneal graft construction are summarized, and future development directions are suggested.

Synergistic tailoring of adsorption and vacancy enrichment in lamellar stacked layers of α-MoO3 nanorods by Mg2+ for NO2 gas sensor

Extremely toxic nitrogen dioxide (NO2) was detected using lamellar layered α-MoO3. The stable orthorhombic phase of MoO3 (α-MoO3) with preferential growth along (02k0) and the nano-rectangular rods (NRs) like morphology were observed. The incorporation of Mg2+ in α-MoO3 influenced the morphology and the oxygen vacancies (VO), which were analyzed through Raman, photoluminescence, and X-ray photoelectron spectroscopy. The core level spectra provided direct evidence for VO enrichment in 3 %Mg-α-MoO3 via emergence of peak at 531.02 eV with an area of 45.15 %. NO2 response was analyzed at 150–200 °C with various NO2 concentrations. 3 %Mg-α-MoO3 NRs provided maximum response of 133.9 % for 50 ppm with low limit of detection (LOD) of 250 ppb with good response (193 s) and recovery (260 s) transient behaviors. The fabricated sensor shows high selectivity to NO2 among H2S, SO2, N2O, and NH3, also good repeatability suggesting potential suitability for NO2 detection.

Experimental determination of the charring rate of cross-laminated timber panels

Recent design guides include charring models for cross-laminated plane timber (CLT) members. When the bond line integrity is not maintained, charring is illustrated as a combination of sequenced phases. Significant research has been conducted on the charring behaviour of CLT panels, and the criterion of 300 °C has been an accepted definition for the char front line. The charring rate of a solid wood-based panel is determined by the char depth divided by the time to reach the char depth. In the CLT structure, this method can be applied to the first lamella layer. However, due to the char fall-off, it cannot be directly applied to the lamella layers behind the first layer. In this research, eight fire tests were conducted to investigate how charring rates of different lamella layers can be determined from measured temperatures. An assessment method based on the mean char depth development determined from experimental temperature distributions of CLT panels is introduced. Also, the effects of thermocouple positioning and specimen orientation on the assessment results were analysed. The charring rates determined for both horizontal and vertical specimens align well with the results calculated using the European Charring Model and a post-protection factor k3 of 2.

Self-Assembly of Hierarchical High-χ Fluorinated Block Copolymers with an Orthogonal Smectic-within-Lamellae 3 nm Sublattice and Vertical Surface Orientation.

Hierarchical structure-within-structure assemblies offer a route toward increasingly complex and multifunctional materials while pushing the limits of block copolymer self-assembly. We present a detailed study of the self-assembly of a series of fluorinated high-χ block copolymers (BCPs) prepared via postmodification of a single poly(styrene)-block-poly(glycidyl methacrylate) (S-b-G) parent polymer with the fluorinated alkylthiol pendent groups containing 1, 6, or 8 fluorinated carbons (termed trifluoro-ethanethiol (TFET), perfluoro-octylthiol (PFOT), and perfluoro-decylthiol (PFDT), respectively). Bulk X-ray scattering of thermally annealed samples demonstrates hierarchical molecular assembly with phase separation between the two blocks and within the fluorinated block. The degree of ordering within the fluorinated block is highly sensitive to synthetic variation; a lamellar sublattice was formed for S-b-GPFOT and S-b-GPFDT. Thermal analyses of S-b-GPFOT reveal that the fluorinated block exhibits liquid crystal-like ordering. The complex thin-film self-assembly behavior of an S-b-GPFOT polymer was investigated using real-space (atomic force microscopy and scanning electron microscopy) and reciprocal-space (resonant soft X-ray scattering (RSoXS), grazing incidence small- and wide-angle scattering) measurements. After thermal annealing in nitrogen or vacuum, films thicker than 1.5 times the primary lattice spacing exhibit a 90-degree grain boundary, exposing a thin layer of vertical lamellae at the free interface, while exhibiting horizontal lamellae on the preferential (polystyrene brush) substrate. RSoXS measurements reveal the near-perfect orthogonality between the primary and sublattice orientations, demonstrating hierarchical patterning at the nanoscale.

Novel Fe-MOF@Cu/NiAl-LDH as Photo-Catalysts in Methane Bireforming: Effect of Preparation Strategy

In this work, Fe-MOF@Ni/CuAl-LDH nanocomposites are developed for the first time in photocatalytic CO2/CH4 conversion to ultrapure formaldehyde. The reaction takes place in a dynamic (continuous flow) photosystem working under atmospheric pressure in presence of visible-light irradiation. The visible-light-active photocatalysts are prepared using two strategies in order to enhance both morphology and optical properties of the new composite. First strategy based on growing of MOF on the in-situ N2 exfoliated LDH using solvothermal reaction (FMNHT and FMCHT), where, the MOF is formed on surface and/or inside lamellar layer. The second based on formation of LDH around the previously prepared Fe-MOF via microwave assisted method (NFMMW and CFMMW). The data herein indicate that, both samples NFMMW and CFMMW, have LDH/MOF strong electronic coupling and exhibit an adjustable band gap share in improve charge generation/separation rate, reduce e−/h+ recombination rate and increase light absorption capacity. Those characteristics provide higher efficiency in photocatalytic CH4/CO2 conversion and give high selectivity toward ultrapure formaldehyde formation (99.9%).

Numerical Analysis and Experimental Study on Side Dam Temperature and Stress Field of Two‐Roll Casting

The side sealing technology is crucial for ensuring the quality and process stability in twin‐roll casting (TRC). Investigating the temperature and stress distribution in side dams under operational conditions is vital, especially in understanding the causes of side dam fractures. Optimal performance of side dam materials is achieved when the boron nitride (BN) matrix is fine and homogeneous, with zirconium dioxide (ZrO2) and silicon carbide (SiC) particles evenly dispersed throughout. The fracture of the side dam after casting is mainly caused by BN interlamellar tear. The coexistence of BN lamellar tearing and BN layer fracture leads to the fracture of the side dam during the casting process. Through finite element simulation, the effects of variables such as pouring temperature, preheating temperature, and side dam thickness on temperature and stress distribution were analyzed. The findings indicate that a preheating temperature range of 1200–1300 °C minimizes thermal stress in the side dam. Building on these findings, a composite structure for the side dam is developed. Both internal and external composite structures have shown significant effectiveness in reducing thermal stress. These results are pivotal in extending the service life of side dams and enhancing the stability of the TRC process.

Laevaptychi as reliable paleotemperature archives: high-resolution stable isotope compositions of Kimmeridgian (Jurassic) lamellar structured aspidoceratid lower mandibles from Zengővárkony (Mecsek Mountains, Hungary)

Fieldwork provided well-preserved Laevaptychus sp. ex gr. hoplisus–obliquus specimens from the lower Kimmeridgian of Zengővárkony (Mecsek Mountains, south Hungary). This study presents the stable isotope analysis of these aptychi and control samples from brachiopods (Nucleata and Pygope) derived from the Zengővárkony section bed 3. Rarely observed structures in the upper lamellar layers of the studied laevaptychi revealed 24–32 concentric lamellae that represent primary textural features and indicate excellent preservation. After careful screening for diagenetic effects, stable oxygen isotope compositions yielded seawater temperatures between 20 and 26 °C in good agreement with earlier studies on Jurassic formations, with improved precision. Our research presents for the first time that well-preserved laevaptychi may be a reliable data source for paleoclimate and paleotemperature reconstructions.Graphical abstract

Potential application of carboxymethyl cellulose/sodium alginate aerogels loaded with algal biomass for disinfection of contaminated water

Many developing countries still lack enough credentials for a healthy and safe water supply. To control the circulation of waterborne diseases and ensure consumer safety, a significant problem is eliminating dangerous microbes from water systems using efficacious water disinfection technology. This current research work's objective was to encapsulate the algal biomass inside the porous structures of these sponge materials. Freeze drying technique was used to prepare these sponge materials using carboxymethyl cellulose (CMC) and sodium alginate (SA). The aerogel solution was loaded with different concentrations of algal biomass. The algal biomass was encapsulated owing to the presence of many interstitial pores with these spongy materials. The obtained data depicted that aerogels exhibited lamellar layers with immense porous structures. The mechanical properties of aerogels were enhanced with the addition of algal biomass. Inactivating 100% of both Gram-negative and Gram-positive bacteria, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis were achieved within 120 min after treatment by Sp.m-3 @CM-SA aerogel. The biocidal effect of the Sp.m-3 @CM-SA aerogel is thought to be controlled primarily by surface-controlled processes that rely on direct contact between the bacterial cells and the interface of the aerogel. This suggests that the antimicrobial activity of the aerogel is related to the material's surface properties, which may facilitate the release of antimicrobial compounds from the algal biomass loaded in the aerogel.

Effects of bacterial consortium enhanced recycled coarse aggregates on self‐healing concrete immobilized with Bacillus megaterium MTCC 1684 and Bacillus subtilis NCIM 2193

AbstractThe strength and durability properties of the recycled aggregate concrete (RAC) have been affected by the cracks and the weak interfacial transition zone (ITZ) of the recycled coarse aggregates (RCA). However, the mechanical and physical features of RCA can be improved by microbially induced calcite precipitation (MICP). Therefore, immobilization techniques were used to protect and maintain the high efficiency of Bacillus bacteria for the formation and precipitation of calcium carbonates in self‐healing concrete over a period of time. The objective of the present study was to show the viability of the immobilized bacterial consortium‐enhanced RCA to form self‐healing cracks. Further, the self‐healing capability of enhanced RCA was investigated along with two other immobilization methods, that is, RCA and hydrated lime and brick powder (HBr)‐immobilized bacteria. The experimental results show that the increase in the bio‐deposition time improved the physical and mechanical properties of the RCA. Further, subsequently 56 days of the healing incubation period, the immobilized consortium‐enhanced RCA concrete specimens completely healed the cracks of width 0.58 mm. However, the equivalent cracks of width 0.56 mm were also recovered by the HBr immobilized bacterial cultures. Furthermore, the field emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) and X‐ray diffraction (XRD) analysis revealed that the existence of precipitation at the crack surface was calcium carbonate with a regular cubic‐shaped and lamellar layer morphology. The outcomes of the current study show that consortium‐enhanced RCA has promising potential to develop self‐healing concrete with self‐repaired and improved durability properties in the concrete construction field.

Synergistic silver doping and N vacancy promoting photocatalytic performances of carbon nitride for pollutant oxidation and hydrogen production

Carbon nitride (C3N4) has attracted immense interest as a low-cost, non-toxic and naturally abundant raw material. However, graphite-like phase carbon nitride (g-C3N4) still suffers from poor visible light absorption, fast charge carrier recombination, slow electron mobility and relatively fewer surface-active sites. In this work, we synthesized silver-doped N vacancy-rich carbon nitride (AgCN) with convoluted ultra-thin lamellar layers from Ag precursors and melamine-cyanuric acid monomers using a self-assembly supramolecular strategy. AgCN exhibited excellent photocatalytic performance and stability. The introduction of N vacancies disrupted the off-domain π-bonds and weakened the conjugation effect of the triazine ring elements. The large specific surface area of the convoluted ultra-thin lamellar structure helps suppress the aggregation of active silver centers, and the Ag-N2C2 bond acts as a bridge for photoexcited charge transfer to promote the separation and transfer of photogenerated electron/hole pairs for surface redox reactions. As a result, AgCN exhibited excellent photocatalytic performance for photodegradation of rhodamine B (RhB) and hydrogen production (1.69 mmol g-1h−1), well outperforming the pristine CN. Density flooding theory (DFT) calculations revealed the improved conductivity and efficient separation of electron-hole pairs in AgCN at the excited state, generating superoxide radicals, singlet oxygen and holes.

Anisotropic deformation mechanisms in textured nanotwined Cu under shock loading

In this paper, a model of nanotwinted Cu with [111] texture is constructed, and the anisotropic response mechanism and microscopic deformation mechanism are investigated under shock loading with the impact velocity of 0.5 km/s, 1 km/s, 1.5 km/s and 2.5 km/s from 0°, 45° and 90° loading directions by molecular dynamics simulations. It is found that the textured nanotwinned Cu has obvious anisotropy under 0.5 km/s, 1 km/s and 1.5 km/s, and there are secondary yield and two-stage plastic relaxation under 90° loading. However, the anisotropic response is not obvious under hypervelocity impact (2.5 km/s). Under the shock loading, a large number of intrinsic stacking fault appear, among which the content of 0° and 45° is relatively higher than 90° shock. Under different loading direction, the behavior of multiple twins and dislocation motion varies. Specifically, at 0° loading, multiple twins emit dislocation motion simultaneously, leading to the formation of a large number of faults. At 90° loading, the twin boundary effectively blocks dislocation motion, resulting in less deformation. Under 45° loading, the deformation mode differs from both 0° and 90° loading, causing the original twin boundary to be destroyed and recombined into a new twin lamellar layer with varying thickness. This process creates intrinsic layer faults as well.

A Novel Fiber-Reinforced Poroviscoelastic Bovine Intervertebral Disc Finite Element Model For Organ Culture Experiment Simulations.

Intervertebral disc (IVD) degeneration and methods for repair and regeneration have commonly been studied in organ cultures with animal IVDs under compressive loading. With the recent establishment of novel multiaxial organ culture systems, accurate predictions of the global and local mechanical response of the IVD are needed for control system development and to aid in experiment planning. This study aimed to establish a finite element model of bovine IVD capable of predicting IVD behavior at physiological and detrimental load levels. A finite element model was created based on the dimensions and shape of a typical bovine IVD used in organ culture. The nucleus pulposus (NP) was modelled as a neo-Hookean poroelastic material and the annulus fibrosus (AF) as a fiber-reinforced poroviscoelastic material. The AF consisted of 10 lamella layers and the material properties were distributed in radial direction. The model outcome was compared to a bovine IVD in a compressive stress-relaxation experiment. A parametric study was conducted to investigate the effect of different material parameters on the overall IVD response. The model was able to capture the equilibrium response, and the relaxation response at physiological and higher strain levels. Permeability and elastic stiffness of the AF fiber network affected the overall response most prominently. The established model can be used to evaluate the response of the bovine IVD at strain levels typical for organ culture experiments, to define relevant boundaries for such studies and to aid in the development and use of new multiaxial organ culture systems.

Characterization of rat vertebrae cortical bone microstructures using confocal Raman microscopy combined to tomography and electron microscopy

BackgroundThe rat vertebrae is a good model to study bone regeneration after implantation of biomaterials used to treat bone loss, a major problem in oral and dental surgery. However, the precise characterization of bone microstructures in the rat vertebrae has not been reported. Therefore, the aim of this study was to achieve the complete analysis of such bone, at different scales, in order to have a clear model of healthy bone for comparison with regenerated bone. MethodsIn order to image the cortical bone of rat caudal vertebra, confocal Raman microscopy was combined with high resolution X-ray micro computed tomography (micro-CT), with scanning electron microscopy (SEM) using backscatter electron imaging and with more conventional histology coloration techniques. SEM and Raman microscopy were done in various regions of the cortical bone corresponding to external, middle and internal areas. The spongy bone was imaged in parallel. Micro-CT was performed on the whole vertebra to monitor the network of haversian canals in the cortical bone. Osteonic canals characteristics, and relative chemical composition were analysed in several regions of interest, in cortical and spongy bone. Five rats were included in this study. ResultsOn micro-CT images, differences in intensity were observed in the cortical bone, substantiated by SEM. Chemical analysis with Raman spectra confirmed the difference in composition between the different regions of the cortical and spongy bone. PCA and k-mean cluster analysis separated these groups, except for the external and middle cortical bone. Peak intensity ratio confirmed these results with a CO3 to ν2 PO4 ratio significantly different for the internal cortical bone. Grayscale images stack extracted from micro-CT showed that global architecture of cortical bone was characterized by a dense and complex network of haversian osteonic canals, starting from the surface towards the vertebrae center. The mean diameter of the canals was 18.4 µm (SD 8.6 µm) and the mean length was 450 µm (SD 152 µm). Finally, Raman reconstructed images of the lamellar bone showed an enlargement of the lamellar layer width, both in circumferential lamellar bone and around haversian canals. ConclusionsMicro-CT and confocal Raman microscopy are good tools to complete classical analysis using optical and electron microscopy. The results and measurements presented in a rat model known for its small inter-individual differences provide the main characteristics of a mature bone. This study will allow the community working on this rat vertebrate model to have a set of characteristics, in particular on the structure of the haversian canals.