Atomistic insight into the promising thermoelectric performance of the copper-based ternary phosphide CaCuP.

A first-principles study on the thermoelectric properties of the copper-based ternary phosphide CaCuP is presented. Self-energy relaxation time approximation and unified theory for lattice transport provide an accurate description of electron-phonon and phonon-phonon scattering. Our work provides an atomistic insight into its high thermoelectric performance, highlighting that nano-structuring can increase the thermoelectric figure of merit by reducing the lattice thermal conductivity.

Establishment of an inspection standard for decomposition and methane production rates of organic waste co-digestion facilities in Korea.

Domestic organic waste resources have increased over the past decade and treatment of this waste via co-digested biogasification facilities is increasing annually. However, inspection standards for such facilities are not well-established. Herein, we aimed to derive calculation formulas and factors related to organic matter decomposition efficiency and methane production rate in accordance with waste treatment facility inspection standards.

Structural basis for ion selectivity in potassium-selective channelrhodopsins.

KCR channelrhodopsins (K-selective light-gated ion channels) have received attention as potential inhibitory optogenetic tools but more broadly pose a fundamental mystery regarding how their K selectivity is achieved. Here, we present 2.5-2.

A unique photochromic UV-A sensor protein, Rc-PYP, interacting with the PYP-binding protein.

Photoactive yellow protein (PYP) is one of the typical light sensor proteins. Although its photoreaction has been extensively studied, no downstream partner protein has been identified to date. In this study, the intermolecular interaction dynamics observed between PYP from Rhodobacter capsulatus (Rc-PYP) and a possible downstream protein, PYP-binding protein (PBP), were investigated.

Effect of Hydrated Ionic Liquid on Photocycle and Dynamics of Photoactive Yellow Protein.

The mechanism by which proteins are solvated in hydrated ionic liquids remains an open question. Herein, the photoexcitation dynamics of photoactive yellow protein dissolved in hydrated choline dihydrogen phosphate (Hy[ch][dhp]) were studied by transient absorption and transient grating spectroscopy. The photocyclic reaction of the protein in Hy[ch][dhp] was similar to that observed in the buffer solution, as confirmed by transient absorption spectroscopy.

Effects of flow-induced shear stress on limbal epithelial stem cell growth and enrichment.

The roles of limbal epithelial stem cells (LESCs) are widely recognized, but for these cells to be utilized in basic research and potential clinical applications, researchers must be able to efficiently isolate them and subsequently maintain their stemness in vitro. We aimed to develop a biomimetic environment for LESCs involving cells from their in vivo niche and the principle of flow-induced shear stress, and to subsequently demonstrate the potential of this novel paradigm. LESCs, together with neighboring cells, were isolated from the minced limbal tissues of rabbits.

Shear stress magnitude is critical in regulating the differentiation of mesenchymal stem cells even with endothelial growth medium.

Human mesenchymal stem cells (MSC) were seeded onto the inner surface of a tubular silicon construct and, after 24 h, were exposed to a shearing stress of either 2.5 or 10 dyne/cm(2) for 1 day. The fluid contained endothelial growth factors in both cases.

Combined effects of surface morphology and mechanical straining magnitudes on the differentiation of mesenchymal stem cells without using biochemical reagents.

Existing studies examining the control of mesenchymal stem cell (MSC) differentiation into desired cell types have used a variety of biochemical reagents such as growth factors despite possible side effects. Recently, the roles of biomimetic microphysical environments have drawn much attention in this field. We studied MSC differentiation and changes in gene expression in relation to osteoblast-like cell and smooth muscle-like cell type resulting from various microphysical environments, including differing magnitudes of tensile strain and substrate geometries for 8 days.

Enhanced differentiation of mesenchymal stem cells into NP-like cells via 3D co-culturing with mechanical stimulation.

This study proposes a three-dimensional co-culturing system of mesenchymal stem cells (MSCs) and nucleus pulposus (NP) cells from New Zealand white male rabbits to differentiate MSCs into NP-like cells. The preferable ratio of MSCs to NP cells and the effects of mechanical stimulation were investigated without biochemical reagents. The preferable ratio was investigated without mechanical stimulation using five groups: Group I (MSC control); Group II (NP cell control); and Groups III, IV, and V, for which the ratios of NP cells to MSCs were 1:1, 1:2, and 2:1, respectively.

Manufacturing of multi-layered nanofibrous structures composed of polyurethane and poly(ethylene oxide) as potential blood vessel scaffolds.

One of the current limitations in using electrospun nanofibrous materials for tissue engineering is that cells have difficulty penetrating into the materials. For this, multi-layered electrospun structures composed of polyurethane (PU) and poly(ethylene oxide) (PEO) were fabricated and tested in vitro. A 20% (w/v) PU solution was electrospun for 30 min, while a 20% (w/v) PEO solution was electrospun for 5, 15 or 30 min, alternatively.

In vitro and animal study of novel nano-hydroxyapatite/poly(epsilon-caprolactone) composite scaffolds fabricated by layer manufacturing process.

The purpose of this study was to propose a computer-controllable scaffold structure made by a layer manufacturing process (LMP) with addition of nano- or micro-sized particles and to investigate the effects of particle size in vitro. In addition, the superiority of this LMP method over the conventional scaffolds made by salt leaching and gas forming process was investigated through animal study. Using the LMP, we have created a new nano-sized hydroxyapatite/poly(epsilon-caprolactone) composite (n-HPC) scaffold and a micro-sized hydroxyapatite/poly(epsilon-caprolactone) composite (m-HPC) scaffold for bone tissue engineering applications.

ERK 1/2 activation in enhanced osteogenesis of human mesenchymal stem cells in poly(lactic-glycolic acid) by cyclic hydrostatic pressure.

The aim of this study was to identify the signal transduction pathways and mechano-transducers that play critical roles in the processes induced by changes in cyclic hydrostatic pressure and fluid shear in 3-dimensional (3D) culture systems. Mesenchymal stem cells were loaded into a polymeric scaffold and divided into three groups according to the stress treatment: static, fluid shear, and hydrostatic pressure with fluid shear. Cells were exposed daily to a hydrostatic pressure of 0.

Enhancement of adipose tissue formation by implantation of adipogenic-differentiated preadipocytes.

Engineered adipose tissue could be used for the reconstruction or augmentation of soft tissues lost due to mastectomy or lumpectomy in plastic and reconstructive surgery. Preadipocytes are a feasible cell source for adipose tissue regeneration. However, the enhancement of the in vivo adipogenic conversion of preadipocytes remains a major task.

Effects of mechanical stimuli and microfiber-based substrate on neurite outgrowth and guidance.

We introduced mechanical stimuli and micropatterned substrate with microfibers to investigate their effects on neurite outgrowth along with nerve growth factor in vitro. Two types of surface morphology were used: a surface that was coated by laminin alone and a surface where in microfibers was added on the laminin surface. PC-12 cells were seeded on both surface types and cultured for 2 d.

Biomechanical comparisons of three different tibial tunnel directions in posterior cruciate ligament reconstruction.

Purpose: To investigate the effects of 3 different tunnel directions on the outcomes of posterior cruciate ligament (PCL) reconstruction surgery based on the forces exerted on the replacement ligament from a biomechanical point of view. The 3 tunnel directions in the proximal tibia are medial, central, and lateral.

Type Of Study: Biomechanical study.

Chondrogenic differentiation of mesenchymal stem cells and its clinical applications.

Tissue engineering has the potential to provide cartilaginous constructs capable of restoring the normal function of native articular cartilage following joint injury or degradation. One approach to functional tissue engineering of cartilage involves the in vitro cultivation of tissue constructs by using: (i) chondrogenic cells that can be selected, expanded, and transfected to overexpress the genes of interest, (ii) scaffolds that provide a defined three-dimensional structure for tissue development and biodegrade at a controlled rate. Understanding the functional potential of the cells and the signaling mechanisms underlying their differentiation should lead to innovative protocols for clinical orthopaedic interventions.

Chondrogenic differentiation of human mesenchymal stem cells using a thermosensitive poly(N-isopropylacrylamide) and water-soluble chitosan copolymer.

Poly(N-isopropylacrylamide) (PNIPAAm) is known to be thermally responsive material and has a lower critical solution temperature (LCST, 32 degrees C) at which a macromolecular transition from a hydrophilic to a hydrophobic structure occurs. Chitosan is a useful natural polymeric biomaterial due to its biocompatibility and biodegradable properties. It has good characteristics for cell attachment, proliferation and viability.

Chemical, structural properties, and osteoconductive effectiveness of bone block derived from porcine cancellous bone.

The purpose of this study is to determine the efficacy of bioactive calcium phosphate obtained from porcine cancellous bone for the treatment of bone defects and nonunion. Porcine cancellous bone blocks were heat treated at 1300 degrees C for 2 h. The chemical composition, calcium-to-phosphate ratio, and microstructure of the porcine bone blocks were examined.