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The article is on cell sheet engineering. It summarizes tissue engineering from its beginnings to the recent latest developments.

Nanomaterials to Solve Corneal Blindness Developed by Indo- Japan Research Team.

Researchers Discover Compound that can Fight Different Types of Viral Diseases.

Study on Dengue Identifies Candidate Susceptibility Genes.

Study Sheds New Light on Ageing Effect on Brain.

A*STAR Scientists First to Identify Stem Cell Key to Lung Regeneration.

The following topics are under this section:

• 50 young scientists awarded with the inaugural XPLORER PRIZE
• Chinese scientist find new possibilities in dengue virus control
• Optimizing microbial microenvironment for development of novel Biophotovoltaics System
• Novel drug for chronic pain relief enter clinical trials
• China taps into artificial intelligence to improve pharmacy services
• Patient in China who received world’s first pig cornea regains eyesight
• China sees its first childbirth through cryopreservation of ovarian tissue
• China toughens crackdown on illegal African swine fever vaccines

A theoretical model for corneal swelling with respect to aqueous inflow, based on corneal dimensions and mechanical and chemical properties, is presented in this paper. The mechanical properties of the corneal stroma, with respect to aqueous inflow, are considered in the basis of swelling mechanics. Equations describing the time course of swelling are also given. With this formulation, we can explain how glaucoma may result if outflow facility decreases faster compared to aqueous inflow. The opposite situation, e.g. of hypotony, may also be considered.

Background: Determining the viscoelastic properties of cornea is important in the fields of understanding of the tissue’s response to mechanical actions and the accurate numerical simulation of corneal biomechanical behavior under the effects of keratoconus and refractive surgery. To address this need, we present an approach to model the viscoelastic response of rabbit cornea from uniaxial test data. Methods: The corneal strip samples from six rabbits were obtained to perform cyclic uniaxial tension tests and stress relaxation tests. We investigated the suitability of six constitutive models, including empirical models and hyperelastic models, by a quasi-linear viscoelastic law. Applying non-linear optimization techniques, we found material parameters for each different strip sample. Results and conclusions: The model gave a better fit to loading data with $R^2>0.99$, and predicted the unloading data in the cyclic uniaxial tests with errors-of-fit ranging from 0.03 to 0.06. The results indicate that the best model is the power of the first invariant of strain with Prony form relaxation model, and that the method to identify the material parameters are valid for modeling the visoelastic response of cornea from uniaxial test data.

Chemical injury to the eye is still an important cause of blindness and serious complications. Gaseous ammonia combines with tissue water to form ammonium hydroxide (NH₄OH). This exothermic reaction results in both heat and chemical burns. Although, over the years, the different biological effects of anhydrous ammonia are well known, its ocular effects are less clearly documented. This study reports the corneal structural alterations that may be induced as a result of ammonia exposure (gas or liquid) that was studied by Fourier transform infrared spectroscopy. The resulted IR spectra were analyzed using the band enhancement procedure. The obtained data clearly indicate that there are different structural and conformational changes (includes lipids and proteins) as the method of exposure to the ammonia differ, and due to the increased ammonia occupational exposure, there is an insistent need for the development of ophthalmic medications.

Multiphoton microscopy (MPM), with the advantages of improved penetration depth, decreased photo-damage, and optical sectioning capability, has become an indispensable tool for biomedical imaging. The combination of multiphoton fluorescence (MF) and second-harmonic generation (SHG) microscopy is particularly effective in imaging tissue structures of the ocular surface. This work is intended to be a review of advances that MPM has made in ophthalmic imaging. The MPM not only can be used for the label-free imaging of ocular structures, it can also be applied for investigating the morphological alterations in corneal pathologies, such as keratoconus, infected keratitis, and corneal scar. Furthermore, the corneal wound healing process after refractive surgical procedures such as conductive keratoplasty (CK) can also be studied with MPM. Finally, qualitative and quantitative SHG microscopy is effective for characterizing corneal thermal denaturation. With additional development, multiphoton imaging has the potential to be developed into an effective imaging technique for in vivo studies and clinical diagnosis in ophthalmology.

The three-dimensional (3D) mechanical response of the cornea to intraocular pressure (IOP) elevation has not been previously reported. In this study, we use an ultrasound speckle tracking technique to measure the 3D displacements and strains within the central 5.5mm of porcine corneas during the whole globe inflation. Inflation tests were performed on dextran-treated corneas (treated with a 10% dextran solution) and untreated corneas. The dextran-treated corneas showed an inflation response expected of a thin spherical shell, with through-thickness thinning and in-plane stretch, although the strain magnitudes exhibited a heterogeneous spatial distribution from the central to more peripheral cornea. The untreated eyes demonstrated a response consistent with swelling during experimentation, with through-thickness expansion overriding the inflation response. The average volume ratios obtained in both groups was near 1 confirming general incompressibility, but local regions of volume loss or expansion were observed. These results suggest that biomechanical measurements in 3D provide important new insight to understand the mechanical response of ocular tissues such as the cornea.

While finite elements has been considered during the last decades as the universal tool to perform simulations in biomechanics, a recently developed wide family of methods, globally coined as meshless methods, has emerged as an attractive choice for an increasing variety of engineering problems. They present some key advantages such as the absence of a mesh in the traditional sense, particularly important in domains of very complex geometry, a less sensitivity to the nodal distribution and therefore to the implicit mesh distorsion what is especially interesting to handle problems under finite strains and large displacements in a Lagrangian framework. Here, we analyze the convenience and possible advantages of using meshless methods in numerical simulations of soft biological tissues. Biological tissues are usually nonlinear, anisotropic, inhomogeneous, viscoelastic, and undergo large deformations, so these methods seem to be an appealing possibility for this type of applications. In particular, we discuss the use of one of these methods, the so-called natural element method that has specific and important features as interpolatory character, easy handling of geometry, and essential boundary conditions via the so-called alpha-NEM extension, well-defined mathematical properties and a simple computer implementation. Different examples are solved using this approach including the human cornea, the temporo-mandibular joint, knee ligaments, and the passive behavior of the heart.