Human Umbilical Cord Blood Stem Cells Differentiate into Keratinocytes under In Vitro Conditions and Culturing Differentiated Cells on Bacterial Cellulose Film

Mesenchymal stem cells (MSC) are capable of self renewing and differentiating into other cell types. Human umbilical cord blood (HUCB) has been investigated as an alternative source to bone marrow. The aim of our examinations was to investigate MSC of HUCB could differentiate into keratinocytes under in vitro conditions. In this study, we examined the differentiation with chemical compounds, then to identify the stem cells are differentiated or not, PCR by using the expression of gene cytokeratin 18 was performed and to examine the proliferation characteristic of differentiated keratinocyte from HUCBMSCs, cultured them on cellulose film. Analysis of PCR confirmed the expression of cytokeratin 18 in keratinocytes; results of our study show that cellulose film isn’t a compatible substrate for differentiated keratinocytes. And growth factor, BMP4, with hydrocortisone and ascorbic acid with specific amounts is an appropriate induction factor for inducing of differentiation into keratinocytes

Human Peripheral Blood Derived Hematopoietic Stem Cell: History, the Isolation Methods and Investigation of Different Parameters Effects on Their Differentiation to the Body Cells

Blood and the system that forms it, known as the hematopoietic system, consist of many cell types with specialized functions. Red blood cells (erythrocytes) carry oxygen to the tissues. Platelets (derived from megakaryocytes) help prevent bleeding. Granulocytes (neutrophils, basophils and eosinophils) and macrophages (collectively known as myeloid cells) fight infections from bacteria, fungi, and other parasites such as nematodes (ubiquitous small worms). Some of these cells are also involved in tissue and bone remodeling and removal of dead cells. B-lymphocytes produce antibodies, while T-lymphocytes can directly kill or isolate by inflammation cells recognized as foreign to the body, including many virus-infected cells and cancer cells. Many blood cells are short-lived and need to be replenished continuously; the average human requires approximately one hundred billion new hematopoietic cells each day. The continued production of these cells depends directly on the presence of Hematopoietic Stem Cells (HSCs), the ultimate, and only, source of all these. Peripheral blood stem cells (PBSC) are rapidly becoming the primary rescue modality for autologous transplantation and are now actively being investigated in the allogeneic transplant setting. Many investigators and clinical researchers believe that PBSC are likely to replace bone marrow stem cells entirely, for use in clinical transplantation in the not too distant. Hematopoietic stem cells (HSCs) are the blood cells that give rise to all the other blood cells. They give rise to the myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells), and lymphoid lineages (T-cells, B-cells, NK-cells). The definition of hematopoietic stem cells has changed in the last two decades. The hematopoietic tissue contains cells with long-term and short-term regeneration capacities and committed multipotent, oligopotent, and unipotent progenitors

PVA-Based Nanofibers Containing Chitosan Modified with Graphene Oxide and Carbon Quantum Dot-Doped TiO2 Enhance Wound Healing in a Rat Model

Electrospun nanofibrous constructs based on nanoparticles and biopolymers have recently been used in tissue engineering because of their similarity to the extracellular matrix in nature. In this study, electrospun chitosan-carbon quantum dot-titanium dioxide-graphene oxide (CS-CQD-TiO2-GO) nanofibrous mats were synthesized for use as wound dressings by the electrospinning method. To increase the biodegradation rate and water resistance, the fabricated nanofibrous mats were cross-linked. SEM images showed a uniform and coherent structure of CS-CQD-TiO2-GO nanocomposites and CS-CQD-TiO2-GO electrospun nanofibers mats. FTIR analysis, XRD pattern, SEM mapping, and EDS spectrum demonstrate the accuracy of the synthesis as well as the elemental and chemical structure of the nanofibrous mat. The water contact angle indicated that the nanofibrous mat had a hydrophilic property, which is essential for controlling wound exudates. The tensile strength and elongation tests showed that the nanofibrous mat has suitable mechanical properties for wound dressing, including significant flexibility and strength. Interestingly, antimicrobial testing illustrated that the fabricated nanofibrous mat had antibacterial activity against Gram-negative and Gram-positive bacteria. Appropriate cell viability and cytocompatibility of treated mouse fibroblast NIH3T3 cells with the nanofibrous mat were determined using an MTT assay. The animal study results confirmed the proper potential of the nanofibrous mat in wound dressing applications

The role of rock joint frictional strength in the containment of fracture propagation

The fracturing phenomenon within the reservoir environment is a complex process that is controlled by several factors and may occur either naturally or by artificial drivers. Even when deliberately induced, the fracturing behaviour is greatly influenced by the subsurface architecture and existing features. The presence of discontinuities such as joints, artificial and naturally occurring faults and interfaces between rock layers and microfractures plays an important role in the fracturing process and has been known to significantly alter the course of fracture growth. In this paper, an important property (joint friction) that governs the shear behaviour of discontinuities is considered. The applied numerical procedure entails the implementation of the discrete element method to enable a more dynamic monitoring of the fracturing process, where the joint frictional property is considered in isolation. Whereas fracture propagation is constrained by joints of low frictional resistance, in non-frictional joints, the unrestricted sliding of the joint plane increases the tendency for reinitiation and proliferation of fractures at other locations. The ability of a frictional joint to suppress fracture growth decreases as the frictional resistance increases; however, this phenomenon exacerbates the influence of other factors including in situ stresses and overburden conditions. The effect of the joint frictional property is not limited to the strength of rock formations; it also impacts on fracturing processes, which could be particularly evident in jointed rock masses or formations with prominent faults and/or discontinuities

Numerical modeling of hydraulic fracture propagation, closure and reopening using XFEM with application to in-situ stress estimation

In this paper, a fully coupled model is developed for numerical modeling of hydraulic fracturing in partially saturated weak porous formations using the extended finite element method, which provides an effective means to simulate the coupled hydro-mechanical processes occurring during hydraulic fracturing. The developed model is for short fractures where plane strain assumptions are valid. The propagation of the hydraulic fracture is governed by the cohesive crack model, which accounts for crack closure and reopening. The developed model allows for fluid flow within the open part of the crack and crack face contact resulting from fracture closure. To prevent the unphysical crack face interpenetration during the closing mode, the crack face contact or self-contact condition is enforced using the penalty method. Along the open part of the crack, the leakage flux through the crack faces is obtained directly as a part of the solution without introducing any simplifying assumption. If the crack undergoes the closing mode, zero leakage flux condition is imposed along the contact zone. An application of the developed model is shown in numerical modeling of pump-in/shut-in test. It is illustrated that the developed model is able to capture the salient features bottomhole pressure/time records exhibit and can extract the confining stress perpendicular to the direction of the hydraulic fracture propagation from the fracture closure pressure

Numerical modeling of hydraulic fracture propagation, closure and reopening using XFEM with application to in-situ stress estimation

In this paper, a fully coupled model is developed for numerical modeling of hydraulic fracturing in partially saturated weak porous formations using the extended finite element method, which provides an effective means to simulate the coupled hydro-mechanical processes occurring during hydraulic fracturing. The developed model is for short fractures where plane strain assumptions are valid. The propagation of the hydraulic fracture is governed by the cohesive crack model, which accounts for crack closure and reopening. The developed model allows for fluid flow within the open part of the crack and crack face contact resulting from fracture closure. To prevent the unphysical crack face interpenetration during the closing mode, the crack face contact or self-contact condition is enforced using the penalty method. Along the open part of the crack, the leakage flux through the crack faces is obtained directly as a part of the solution without introducing any simplifying assumption. If the crack undergoes the closing mode, zero leakage flux condition is imposed along the contact zone. An application of the developed model is shown in numerical modeling of pump-in/shut-in test. It is illustrated that the developed model is able to capture the salient features bottomhole pressure/time records exhibit and can extract the confining stress perpendicular to the direction of the hydraulic fracture propagation from the fracture closure pressure

Estimating River Depth from SWOT-Type Observables Obtained by Satellite Altimetry and Imagery

The proposed Surface Water and Ocean Topography (SWOT) mission aims to improve spaceborne estimates of river discharge through its measurements of water surface elevation, river width and slope. SWOT, however, will not observe baseflow depth, which limits its value in estimating river discharge especially for those rivers with heterogeneous channel geometry. In this study, we aim to obtain river depths from spaceborne observations together with in situ data of river discharge. We first obtain SWOT-like observables from current satellite techniques. We obtain river water level and slope time series from multi-mission altimetry and effective river width from satellite imagery (MODIS). We then employ a Gauss–Helmert adjustment model to estimate average river depth for 16 defined reaches along the Po River in Italy, for which we use our spaceborne observations in two recognized models for discharge estimation. The average river depth estimates along the Po River are validated against surveyed cross-section information, which shows a generally good agreement in the range of ∼10% relative root mean squared error. Furthermore, we analyzed the sensitivity of error in the estimated river depth to errors of individual parameters. We show that the estimated river depth is less influenced by errors of river width and river discharge, while it is strongly influenced by errors in water level. This result gives a perspective to the SWOT mission to infer river depth by coarse estimates of river width and discharge

Corona virus and elderly social isolation: A systematic review

Introduction: The elderly more than others in the society were affected by the corona epidemic. Social isolation as one of the important consequences of corona pandemic, affected the elderly. This review study was performed with aim to investigate studies related to social isolation of the elderly during the corona virus epidemic. Methods: In this systematic review, to find the article entitled elderly social isolation and Covid-19, the articles published in English from the beginning of the Corona virus pandemic to 2021 were searched in databases of Scopus, ISI (web of science), PubMed (Medline), Cochrane Library, and Science direct using MeSH and the keywords of "social isolation", "elderly", "loneliness", "coronavirus", "COVID -19", "SARS COVID -2", "pandemic", "elderly", alone and in combination using the operators AND and OR. Results: A total of 11 studies related to Covid-19 and social isolation were included in the study. The findings showed that the COVID-19 pandemic and health policies have exacerbated feelings of loneliness and isolation in the elderly. Loneliness and social isolation in the elderly have increased due to the implementation of preventive protocols such as social distance and quarantine. Conclusion: Attention to approaches which reduce social isolation in the elderly during the COVID-19 pandemic is one of the important interventions that should be considered by government and policy makers to reduce the rate of harm in the elderly and consequently reduce health costs to compensate its side-affects. © 2023, Mashhad University of Medical Sciences. All rights reserved

Investigation of Isolating of Human Mesenchymal Stem Cells From Umbilical Cord Blood and Labeling them with 99m Technetium

Tissue engineering through the imitation of nature has the ability to deal with the crisis caused by the shortage of donor organs and tissues. With regard to the ethical problems of extraction of embryonic stem cell, the present study investigated the isolation of mesenchymal stem cells from umbilical cord blood. Also investigated labeling of isolated stem cells with 99mTechnetium (99mTC). In this research we explore the Ficoll density gradient method. Then to prove the isolated cells are multipotent, we differentiated them into adipocyte and osteocyte. Flow cytometric analysis of CD34 and CD38 was performed to examine the expression of these specific markers. After labeling the cells, the efficiency is measured by TLC papers and gamma counter. The results showed that the umbilical cord blood can be introduced as an appropriate cell source due to easy availability, low cost and no risk to mother or baby. The isolated stem cells have high potency of proliferating and differentiating. Also measurement of labeling efficiency at different times indicates high absorption of these cells. due to the difficulties in the isolation of adult stem cells from tissues; cord blood is a reliable alternative source