Biogenic gold nanotriangles and spherical silver nanoparticles were synthesized by a simple procedure using Aloe vera leaf extract as the reducing agent. This procedure offers control over the size ...of the gold nanotriangle and thereby a handle to tune their optical properties, particularly the position of the longitudinal surface plasmon resonance. The kinetics of gold nanotriangle formation was followed by UV-vis-NIR absorption spectroscopy and transmission electron microscopy (TEM). The effect of reducing agent concentration in the reaction mixture on the yield and size of the gold nanotriangles was studied using transmission electron microscopy. Monitoring the formation of gold nanotriangles as a function of time using TEM reveals that multiply twinned particles (MTPs) play an important role in the formation of gold nanotriangles. It is observed that the slow rate of the reaction along with the shape directing effect of the constituents of the extract are responsible for the formation of single crystalline gold nanotriangles. Reduction of silver ions by Aloe vera extract however, led to the formation of spherical silver nanoparticles of 15.2 nm +/- 4.2 nm size.
In the recent years, a paradigm shift is taking place where metallic/synthetic implants and tissue grafts are being replaced by tissue engineering approach. A well designed three-dimensional scaffold ...is one of the fundamental tools to guide tissue formation in vitro and in vivo. Bone is a highly dynamic and an integrative tissue, and thus enormous efforts have been invested in bone tissue engineering to design a highly porous scaffold which plays a critical role in guiding bone growth and regeneration. Numerous techniques have been developed to fabricate highly interconnected, porous scaffold for bone tissue engineering applications with the help of biomolecules such as chitosan, collagen, gelatin, silk, etc. We aim, in this review, to provide an overview of different types of fabrication techniques for scaffold preparation in bone tissue engineering using biological macromolecules.
To improve the quality of life of diabetic patients, oral delivery of insulin would be better than subcutaneous injection, and the encapsulation of insulin for its oral delivery is a promising ...alternative one. In this study, we prepared an oral insulin delivery system using thiolated chitosan nanoparticles (TCNPs) loaded with insulin (Ins) and tested under in vitro and in vivo systems. TCNPs prepared from CS and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) at 4:1 ratio showed 220 ± 4 nm, 2.3 ± 1 mV, and 119 ± 4 μmol g−1 in their size, charge and sulfhydryl content, respectively. There was a sustained release of insulin from the TCNPs at pH 5.3. TCNPs treatment did not alter cell viability in vitro and oral administration of TCNPs reached over the tip of the microvilli near the intestinal mucosa in vivo. There were increased and decreased the levels of insulin and glucose in the blood, respectively when Ins-TCNPs were orally administered in the diabetes induced rats. Thus, our results suggested that the insulin stays significantly for a prolonged period to make bio-distribution and bioavailability due to its interaction with the mucus of the intestine, thus offering a better oral insulin delivery system for diabetic patients.
•Chemical modification and characterization of thiolated chitosan nanoparticles-Insulin (TCNPs-Ins) using PETMP•Proposed the structure-activity relationship and sustained release of TCNPs-Ins at in vitro•TCNPs facilitate a prolonged residence time of orally delivered insulin in the ileum region of Wister rat by FITC conjugation.
Vascular endothelial growth factor-A (VEGF-A) is essential for endothelial cell functions associated with angiogenesis. Signal transduction networks initiated by VEGFA/VEGFR2, the most prominent ...ligand-receptor complex in the VEGF system, leads to endothelial cell proliferation, migration, survival and new vessel formation involved in angiogenesis. Considering its biomedical importance, we have developed the first comprehensive map of endothelial cell-specific signaling events of VEGFA/VEGFR2 system pertaining to angiogenesis. Screening over 20,000 published research articles and following the post-translational modification (PTM) and site specificity of VEGFR2, we have documented 240 proteins and their diverse PTM-dependent reactions involved in VEGFA/VEGFR2 signal transduction. From the ligand-receptor complex, this map has been extended to the level of major transcriptionally regulated genes for which the signaling cascades leading to their transcription factors are reported. We believe that this map would serve as a novel platform for reference, integration, and representation and more significantly, the progressive analysis of dynamic features of VEGF signaling in endothelial cells including their cross-talks with other ligand-receptor systems involved in angiogenesis.
Friction stir welding is an innovative welding process for similar and dissimilar joining of the materials effectively. FSW simply modified the grain structure and also improved the strength of the ...joints for any type of alloying elements. This experimental study planned to carry out the joining process for dissimilar materials such as aluminium alloys 5083 and 7068. Three different types of tools are involved to find the ultimate tensile strength and Vickers hardness. The tool types are straight cylindrical tool, taper cylindrical tool, and triangular tool. The process factors for this investigation are a rotational speed of 800, 1000, 1200, and 1400 rpm, welding speed of 30, 40, 50, and 60 mm/min, axial force of 3, 4, 5, and 6 kN, and plate thickness of 5, 6, 7, and 8 mm. The hardness value and the ultimate tensile strength were increased in the welding zone, which proves the effects of tool profiles are efficiently utilized.
We establish a one-to-one mapping between entanglement energy, entropy, and temperature (quantum entanglement mechanics) with Komar energy, black hole entropy, and Hawking temperature, respectively. ...We show this explicitly for 4D spherically symmetric asymptotically flat and nonflat space-times with single and multiple horizons. We exploit an inherent scaling symmetry of entanglement entropy and identify scaling transformations that generate an infinite number of systems with the same entanglement entropy, distinguished only by their respective energies and temperatures. We show that this scaling symmetry is present in most well-known systems starting from the two-coupled harmonic oscillator to quantum scalar fields in spherically symmetric space-time. The scaling symmetry allows us to identify the cause of divergence of entanglement entropy to the generation of (near) zero-modes in the systems. We systematically isolate the zero-mode contributions using suitable boundary conditions. We show that the entanglement entropy and energy of quantum scalar field scale differently in space-times with horizons and flat space-time. The relation E = 2TS , in analogy with the horizon's thermodynamic structure, is also found to be universally satisfied in the entanglement picture. We then show that there exists a one-to-one correspondence leading to the Smarr-formula of black hole thermodynamics for asymptotically flat and nonflat space-times.
Despite the spontaneous regenerative properties of autologous bone grafts, this technique remains dilatory and restricted to fractures and injuries. Conventional grafting strategies used to treat ...bone tissue damage have several limitations. This highlights the need for novel approaches to overcome the persisting challenges. Tissue-like constructs that can mimic natural bone structurally and functionally represent a promising strategy. Bone tissue engineering (BTE) is an approach used to develop bioengineered bone with subtle architecture. BTE utilizes biomaterials to accommodate cells and deliver signaling molecules required for bone rejuvenation. Among the various techniques available for scaffold creation, 3D-printing technology is considered to be a superior technique as it enables the design of functional scaffolds with well-defined customizable properties. Among the biomaterials obtained from natural, synthetic, or ceramic origins, naturally derived chitosan (CS) polymers are promising candidates for fabricating reliable tissue constructs. In this review, the physicochemical-biological properties and applications of CS-based 3D-printed scaffolds and their future perspectives in BTE are summarized.
To this day, von Neumann definition of entropy remains the most popular measure of quantum entanglement. Much of the literature on entanglement entropy, particularly in the context of field theory, ...has focused on isolating the UV divergences. Zero-mode divergences of the entanglement entropy are less studied in this context, and apart from being easier to isolate, they offer an interesting insight into the physics of the system. To gain a better understanding of the system in this limit, we develop the free particle approximation of harmonic oscillator, with which we investigate the properties of entropy divergence in continuous bi-partite quantum systems such as the coupled harmonic oscillators and the hydrogen atom. We also show zero-mode divergence of the entropy of environment-induced entanglement in a tri-partite oscillator system. We discuss the implications of our result for field theory and IR structure of gravity.
Non-availability of an ideal alternative for autografts in treating critical-size bone defects is a major challenge in orthopedics. Phytocompounds have been proven to enhance osteogenesis via various ...osteogenic signaling pathways, but its decreased bioavailability and increased renal clearance limit its application. In this study, we designed a biocomposite scaffold comprising gelatin (Gel) and nanohydroxyapatite (nHAp) incorporated with diosmin (DM) and we investigated its bone forming potential in vitro and in vivo. Physiochemical characterization of the scaffold showed that DM had no effect on altering the material characteristics of the scaffold. The addition of DM enhanced the osteoblast differentiation potential of the scaffold in mouse mesenchymal stem cells at both cellular and molecular levels, possibly via the integrin-mediated activation of FAK and ERK signaling components. Using the rat tibial bone defective model, we identified the effect of DM in Gel/nHAp scaffold on enhancing bone formation in vivo. Based on our results, we suggest that Gel/nHAp/DM can be a potential therapeutic agent in scaffold-mediated bone regeneration.
Bone tissue engineering (BTE) relies on biocomposite scaffolds and bioactive molecules for bone regeneration. The present study was aimed to synthesize and characterize biocomposite scaffolds ...containing chitosan (CS), nano-hydroxyapatite (nHAp) and nano‑zirconium dioxide (nZrO2) along with microRNA (miRNA) for BTE applications. miRNAs act as post-transcriptional regulator of gene expression. The fabricated biocomposite scaffolds were characterized using SEM, FT-IR and XRD analyses. The effect of a bioactive molecule (miR-590-5p) with scaffolds was tested for osteoblast differentiation at the cellular and molecular levels using mouse mesenchymal stem cells (C3H10T1/2). The results showed that CS/nHAp/nZrO2 scaffolds promoted osteoblast differentiation, and this effect was further increased in the presence of miR-590-5p in C3H10T1/2 cells. Thus, we suggested that CS/nHAp/nZrO2 scaffolds with miR-590-5p would have potential towards the treatment of bone defects.
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