1,986 research outputs found
Propuesta de mejora en el sistema de adquisiciones del instituto de salud del Estado de México
Contiene tablas y esquemasEl presente trabajo tiene como propósito presentar propuestas de mejora al sistema de adquisiciones y contratación de servicios, a través de un manual de procesos en la contratación pública del ISEM, estas es la elaboración de un manual de procesos en la contratación pública en el ISEM que permita, una mejor integración del Programa Anual de Adquisiciones y Servicios, la integración de procedimientos adquisitivos, y la actualización del proceso de realización de Contrato Pedido
Dexamethasone and Doxycycline Doped Nanoparticles Increase the Differentiation Potential of Human Bone Marrow Stem Cells
Non-resorbable polymeric nanoparticles (NPs) are proposed as an adjunctive treatment
for bone regenerative strategies. The present in vitro investigation aimed to evaluate the effect of
the different prototypes of bioactive NPs loaded with zinc (Zn-NPs), doxycycline (Dox-NPs) or
dexamethasone (Dex-NPs) on the viability, morphology, migration, adhesion, osteoblastic differentiation,
and mineralization potential of human bone marrow stem cells (hBMMSCs). Cell viability,
proliferation, and differentiation were assessed using a resaruzin-based assay, cell cycle analysis, cell
migration evaluation, cell cytoskeleton staining analysis, Alizarin Red S staining, and expression
of the osteogenic-related genes by a real-time quantitative polymerase chain reaction (RT-qPCR).
One-Way ANOVA and Tukey’s test were employed. The resazurin assay showed adequate cell
viability considering all concentrations and types of NPs at 24, 48, and 72 h of culture. The cell cycle
analysis revealed a regular cell cycle profile at 0.1, 1, and 10 g/mL, whereas 100 g/mL produced an
arrest of cells in the S phase. Cells cultured with 0.1 and 1 g/mL NP concentrations showed a similar
migration capacity to the untreated group. After 21 days, mineralization was increased by all the NPs
prototypes. Dox-NPs and Dex-NPs produced a generalized up-regulation of the osteogenic-related
genes. Dex-NPs and Dox-NPs exhibited excellent osteogenic potential and promoted hBMMSC
differentiation. Future investigations, both in vitro and in vivo, are required to confirm the suitability
of these NPs for their clinical application.Ministry of Economy and CompetitivenessEuropean Commission PID2020-114694RB-I00
PID2020-115887GB-I00Ministry of Universities FPU20/00450European Social Fund (ESF)Center for Forestry Research & Experimentation (CIEF)European Commissio
A zinc-doped endodontic cement facilitates functional mineralization and stress dissipation at the dentin surface
The purpose of this study was to evaluate nanohardness and viscoelastic behavior of dentin surfaces treated with two canal sealer cements for dentin remineralization. Dentin surfaces were subjected to: i) 37% phosphoric acid (PA) or ii) 0.5 M ethylenediaminetetraacetic acid (EDTA) conditioning prior to the application of two experimental hydroxyapatite-based cements, containing sodium hydroxide (calcypatite) or zinc oxide (oxipatite), respectively. Samples were stored in simulated body fluid during 24 h or 21 d. The intertubular and peritubular dentin were evaluated using a nanoindenter to assess nanohardness (Hi). The load/displacement responses were used for the nano-dynamic mechanical analysis to estimate complex modulus (E*) and tan delta (?). The modulus mapping was obtained by imposing a quasistatic force setpoint to which a sinusoidal force was superimposed. AFM imaging and FESEM analysis were performed. After 21 d of storage, dentin surfaces treated with EDTA+calcypatite, PA+calcypatite and EDTA+oxipatite showed viscoelastic discrepancies between peritubular and intertubular dentin, meaning a risk for cracking and breakdown of the surface. At both 24 h and 21 d, tan ? values at intertubular dentin treated with the four treatments performed similar. At 21 d time point, intertubular dentin treated with PA+oxipatite achieved the highest complex modulus and nanohardness, i.e., highest resistance to deformation and functional mineralization, among groups. Intertubular and peritubular dentin treated with PA+oxipatite showed similar values of tan ? after 21 d of storage. This produced a favorable dissipation of energy with minimal energy concentration, preserving the structural integrity at the dentin surface
Ultra-structure characterization of self-etching treated cementum surfaces
Objectives: to evaluate the effect of different conditioning treatments on surface roughness and topography of dental cementum. Study Design: Extracted human canines were used for the present study. The mesial surface from the cervical third of the roots were ground flat with wet 600-grit silicon carbide paper. They were polished (up to 1/4 µm diamond paste) and treated as follows: 1) No treatment, 2) 35% H3PO4 during 15 s, 3) Clearfil SE Bond primer (SEB), 4) One-Up Bond F (OUB). The adhesive systems were applied following manufacturer?s instructions. SEB primer and OUB were removed from surfaces by washing and ultrasonic agitation with ascending ethanol solutions. Digital images of treated surfaces (5x5 and 15x15 µm) were obtained by means of an atomic force microscope (AFM) analysis. The average surface roughness (Ra nanometers) of the scanned areas was assessed. Data were analyzed by ANOVA and SNK multiple comparisons tests (p<0.05). Results: phosphoric acid treatment produced the highest mean roughness value, at all scan sizes. At 5x5 µm AFM images, for self-etch adhesive systems no differences in roughness were detected. At 15x15 µm, when One-Up Bond F was employed the lowest value was obtained. Conclusions: When phosphoric acid treatment was applied, cementum surface roughness increased and a strong demineralization with exposed collagen fibers could be observed
En busca de progreso y protección. Experiencias de inmigrantes económicos y refugiados colombianos en Québec, Canadá
El texto sintetiza los resultados de un estudio exploratorio realizado con inmigrantes colombianos en la provincia de Québec, Canadá, a finales de 2006. A manera de tríada teórico-empírica, se analiza y descubre la experiencia migratoria desde la identidad, el territorio y la acción colectiva, a partir de las narraciones de experiencias personales. Con motivaciones y grados de voluntariedad diversos, parece haber una perspectiva optimista de los inmigrantes colombianos con respecto a la reconfiguración de los proyectos individuales y familiares. Mientras mantienen el empeño por conseguir un futuro mejor, los dolores, temores y desconfianzas también sobrepasan las fronteras y viajan en sus memorias. Resignificar tales remembranzas y leerlas en el nuevo contexto canadiense es un reto presente que pasa por las dinámicas individuales y colectivas. En medio de añoranzas de los lugares propios pero distantes y de la proyección de futuros en territorios próximos aún ajenos, se configuran vínculos transnacionales que caracterizan el escenario mundial en el siglo XXI
Three dimensionality in the wake of the flow around a circular cylinder at Reynolds number 5000
The turbulent flow around a circular cylinder has been investigated at Re=5000Re=5000 using direct numerical simulations. Low frequency behavior, vortex undulation, vortex splitting, vortex dislocations and three dimensional flow within the wake were found to happen at this flow regime. In order to successfully capture the wake three dimensionality, different span-wise lengths were considered. It was found that a length LZ=2pDLZ=2pD was enough to capture this behavior, correctly predicting different aspects of the flow such as drag coefficient, Strouhal number and pressure and velocity distributions when compared to experimental values. Two instability mechanisms were found to coexist in the present case study: a global type instability originating in the shear layer, which shows a characteristic frequency, and a convective type instability that seems to be constantly present in the near wake. Characteristics of both types of instabilities are identified and discussed in detail. As suggested by Norberg, a resonance-type effect takes place in the vortex formation region, as the coexistence of both instability mechanisms result in distorted vortex tubes. However, vortex coherence is never lost within the wake.Peer ReviewedPostprint (author's final draft
Zn-containing Adhesives Facilitate Collagen Protection and Remineralization at the Resin-Dentin Interface: A Narrative Review
This work was supported by the Ministry of Economy and Competitiveness and the European Regional Development Fund (Project PID2020-114694RB-100 MINECO/AEI/FEDER/UE). M.T.-O. holds a FPU fellowship from the Ministry of Universities [FPU20/00450].This is a narrative review of the literature assessing the potential effectiveness of doping
dentin polymeric adhesives with zinc compounds in order to improve bonding efficacy, remineralization
and protection against degradation. A literature search was conducted using electronic
databases, such as PubMed, MEDLINE, DIMDI andWeb of Science. Through our search, we found
literature demonstrating that Zn-doped dentin adhesives promote protection and remineralization of
the resin-dentin interfaces. The increased bioactivity has also facilitated dentinal tubules’ occlusion
by crystals’ precipitation contributing to improved sealing efficacy of restorations. Loading dentin
adhesives with zinc gives rise to an increase of both crystallinity of mineral and crosslinking of
collagen. The main role of zinc, in dentin adhesives, is to inhibit collagen proteolysis. We concluded
that zinc exerts a protective effect through binding at the collagen-sensitive cleavage sites of matrixmetalloproteinases
(MMPs), contributing to dentin matrix stabilization. Zinc may not only act as
a MMPs inhibitor, but also influence signaling pathways and stimulate metabolic effects in dentin
mineralization and remineralization processes. Zn-doped adhesives increase the longevity of dentin
bonding through MMPs inhibition. Zn poses a remineralization strategy in demineralized dentin.Ministry of Economy and CompetitivenessEuropean Commission PID2020-114694RB-100 MINECO/AEI/FEDER/UEMinistry of Universities FPU20/0045
Biomimetic Remineralization of an Extracellular Matrix Collagen Membrane for Bone Regeneration
Natural extracellular matrix (ECM) collagen membranes are frequently used for bone regeneration
procedures. Some disadvantages, such as rapid degradation and questionable mechanical
properties, limit their clinical use. These membranes have a heterologous origin and may proceed
from different tissues. Biomineralization is a process in which hydroxyapatite deposits mainly in
collagen fibrils of the matrices. However, when this deposition occurs on the ECM, its mechanical
properties are increased, facilitating bone regeneration. The objective of the present research is to
ascertain if different membranes from distinct origins may undergo biomineralization. Nanomechanical
properties, scanning electron (SEM) and multiphoton (MP) microscopy imaging were performed
in three commercially available ECMs before and after immersion in simulated body fluid solution
for 7 and 21 d. The matrices coming from porcine dermis increased their nanomechanical properties
and they showed considerable mineralization after 21 d, as observed in structural changes detected
through SEM and MP microscopy. It is hypothesized that the more abundant crosslinking andMinistry of Economy and CompetitivenessEuropean Commission PID2020-114694RB-I00
PID2020-113919RB-I00Ministry of Universities FPU20/0045
Doxycycline and Zinc Loaded Silica-Nanofibrous Polymers as Biomaterials for Bone Regeneration
The authors are grateful to Antonio L. Medina-Castillo (NanoMyP-University of Granada
Spin-Off enterprise) for the scientific and technical support at experimental membranes’ designing and fabrication
and to Gertrudis Gomez Villaescusa (University of Granada) for technical assistance at the laboratory.Themain target of bone tissue engineeringis to design biomaterials that support bone regeneration
and vascularization. Nanostructured membranes of (MMA)1-co-(HEMA)1/(MA)3-co-(HEA)2 loaded with
5% wt of SiO2-nanoparticles (HOOC-Si-Membrane) were doped with zinc (Zn-HOOC-Si-Membrane)
or doxycycline (Dox-HOOC-Si-Membrane). Critical bone defects were effectuated on six New
Zealand-bred rabbit skulls and covered with the membranes. After six weeks, the bone architecture
was evaluated with micro computed tomography. Three histological analyses were utilized to
analyse bone regeneration, including von Kossa silver nitrate, toluidine blue and fluorescence.
All membrane-treated defects exhibited higher number of osteocytes and bone perimeter than
the control group without the membrane. Zn-HOOC-Si-Membranes induced higher new bone
and osteoid area than those treated with HOOC-Si-Membranes, and control group, respectively.
Zn-HOOC-Si-Membranes and Dox-HOOC-Si-Membranes attained the lowest ratio M1 macrophages/M2
macrophages. Dox-HOOC-Si-Membranes caused the lowest number of osteoclasts, and bone density.
At the trabecular new bone, Zn-HOOC-Si-Membranes produced the highest angiogenesis, bone thickness,
connectivity, junctions and branches. Zn-HOOC-Si-Membranes enhanced biological activity, attained a
balanced remodeling, and achieved the greatest regenerative efficiency after osteogenesis and angiogenesis
assessments. The bone-integrated Zn-HOOC-Si-Membranes can be considered as bioactive modulators
provoking a M2 macrophages (pro-healing cells) increase, being a potential biomaterial for promoting
bone repair.Ministry of Economy and CompetitivenessEuropean Union (EU)
MINECO/FEDER MAT2017-85999
Determinantes de la demanda de vivienda de interés social (VIS) en la ciudad de Medellín período 2001 – 2006
El sector de la construcción en cualquier país es esencial para lograr mejorar el bienestar de la comunidad y el desarrollo económico de la sociedad, especialmente cuando el concepto de construcción relaciona estructuras, terrenos y servicios básicos que beneficien a los habitantes.56 p.Contenido parcial: Construcción y vivienda -- La vivienda VIS y No VIS -- La vivienda de interés social en Medellín -- Determinantes de la construcción de vivienda de interés social en Medellín. Periodo 2001-200
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