Fabrication of a three-dimensional bone marrow niche-like acute myeloid Leukemia disease model by an automated and controlled process using a robotic multicellular bioprinting system

Dana M. Alhattab,Ioannis Isaioglou,Salwa Alshehri,Zainab N. Khan,Hepi H. Susapto,Yanyan Li,Yara Marghani,Arwa A. Alghuneim,Rubén Díaz-Rúa,Sherin Abdelrahman,Shuroug AL-Bihani,Farid Ahmed,Raed I. Felim 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Acute myeloid leukemia (AML) is a hematological malignancy that remains a therapeutic challenge due to the high incidence of disease relapse. To better understand resistance mechanisms and identify novel therapies, robust preclinical models mimicking the bone marrow (BM) microenvironment are needed. This study aimed to achieve an automated fabrication process of a three-dimensional (3D) AML disease model that recapitulates the 3D spatial structure of the BM microenvironment and applies to drug screening and investigational studies. Methods To build this model, we investigated a unique class of tetramer peptides with an innate ability to selfassemble into stable hydrogel. An automated robotic bioprinting process was established to fabricate a 3D BM (niche-like) multicellular AML disease model comprised of leukemia cells and the BM’s stromal and endothelial cellular fractions. In addition, monoculture and dual-culture models were also fabricated. Leukemia cell compatibility, functionalities (in vitro and in vivo), and drug assessment studies using our model were performed. In addition, RNAseq and gene expression analysis using TaqMan arrays were also performed on 3D cultured stromal cells and primary leukemia cells. Results The selected peptide hydrogel formed a highly porous network of nanofibers with mechanical properties similar to the BM extracellular matrix. The robotic bioprinter and the novel quadruple coaxial nozzle enabled the automated fabrication of a 3D BM niche-like AML disease model with controlled deposition of multiple cell types into the model. This model supported the viability and growth of primary leukemic, endothelial, and stromal cells and recapitulated cell-cell and cell-ECM interactions. In addition, AML cells in our model possessed quiescent characteristics with improved chemoresistance attributes, resembling more the native conditions as indicated by our in vivo results. Moreover, the whole transcriptome data demonstrated the effect of 3D culture on enhancing BM niche cell characteristics. We identified molecular pathways upregulated in AML cells in our 3D model that might contribute to AML drug resistance and disease relapse. Conclusions Our results demonstrate the importance of developing 3D biomimicry models that closely recapitulate the in vivo conditions to gain deeper insights into drug resistance mechanisms and novel therapy development. These models can also improve personalized medicine by testing patient-specific treatments.

Improving the electrical properties of Er-doped CeO2: effect of sintering aids CaO, MgO, and TiO2 on conductivity

Puente-Martínez D. E.,Díaz-Guillén J. A.,González-García K. A.,Montemayor S. M.,Díaz-Guillén J. C.,Burciaga-Díaz O.,Bazaldúa-Medellín M. E.,Padmasree K. P. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

This research reports the synthesis, characterization, and electrical properties of the systems EryCe1−yO2−δ (y = 0.05, 0.1, and 0.15), and the effect of the incorporation of sintering aids (2 wt.% of CaO, MgO, and TiO2) on the electrical properties of the composition Er0.1Ce0.9O1.95, to be used as ceramic solid electrolytes in low-temperature solid oxide fuel cells (LT-SOFC). All EryCe1−yO2−δ samples were obtained by mechanochemistry (20 h of milling) and characterized by XRD. The morphology of the pure sintered compositions and with the incorporation of sintering aids (sintered at 1200 °C) was evaluated by FE-SEM. Electrical properties as a function of temperature (200–650 °C) and frequency (100 Hz–1 MHz) were evaluated by impedance spectroscopy. It reveals an increase of bulk ionic conductivity for higher contents of Er, as the number of oxygen vacancies increases. The higher value of conductivity (6.7 × 10–3 S cm−1) at 650 °C was for the composition Er0.15Ce0.85O1.925, while the ionic conductivity of Er0.1Ce0.9O1.95 at 650 °C increased from 2.68 × 10–3 S cm−1 to a maximum of 1.54 × 10–2 S cm−1 with the incorporation of CaO as additive. These improvements in bulk ionic conductivities can contribute to the development of more efficient electrolytes for the LT-SOFC technology.

More Integrated than Ever? Long-Term Market and Policy Drivers of Intra-Asian Trade

Alejandro Ayuso-Díaz(Alejandro Ayuso-Díaz ),Antonio G. Gómez-Plana(Antonio G. Gómez-Plana ) 세종대학교 경제통합연구소 2023 Journal of Economic Integration Vol.38 No.1

Since the Doha Round stalemate after 2001, trade liberalization has progressed through regional trade agreements (RTAs) and East and Southeast Asia is not unfamiliar with this. Before assessing the effectiveness of recent trade agreements, the long tradition of trade exchange in this region that has lasted for more than 2,000 years necessitates an understanding of the evolution of intra-Asian trade across history. In this regard, this study contributes to the literature examining whether present intra-Asian trade is more or less intense than before 1938. This research outperforms previous studies using a gravity model that controls for changes in GDP and trade costs in the region across four different time periods (between 1840 and 2018). The results show that contemporary regional trade in East and Southeast Asia is slightly less intense than before World War II. A second question addressed is the relevance of trade agreements after the 1985 Plaza Accord on trade integration, compared with market determinants. A second gravity model for regional imports after 1986 is regressed on both policy and market indicators, indicating that the latest wave of intra-Asian trade is characterized by trade complementarities that are fueled by regional foreign direct investment, and free trade agreements are less effective. This result is validated through a network analysis demonstrating the symbiosis between trade and investment flows in the region, which should be considered in RTAs that are in place or in negotiation to take intra-Asian trade beyond its historical limits.

Body fat composition and miR-378 expression profiling in patients with type 1 diabetes

Lissette Duarte,Diego F. García-Díaz,Francisco Pérez-Bravo 대한소아내분비학회 2020 Annals of Pediatirc Endocrinology & Metabolism Vol.25 No.2

Purpose: Type 1 diabetes (T1D) is an autoimmune disease that involves genetic, epigenetic, and environmental factors. Change in body composition is a potential mechanism for explaining the increased incidence of T1D. Micro RNA-378 (miRNA-378) is a positive regulator of adipogenesis that has yet to be studied in such patients. This study aims to evaluate the miRNA-378 expression profile in peripheral mononuclear cells of T1D patients and controls and to determine its possible association with levels of body fat, interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). Methods: Twenty-four T1D subjects and 20 controls under 18 years of age without autoimmune diseases were studied. miRNA-378 expression profile was determined by TaqMan probes. Body composition was determined by multifrequency bioimpedance. IL-6 and TNF-α serum levels were determined by LUMINEX. Anti-GAD65, anti-IA2, and anti-ZnT8 antibodies were quantified in serum by enzyme immunoassays. Statistical significance was considered P<0.05. Results: Similar body mass index and body fat (kg) were observed between the T1D and control subjects (P=0.55 and P=0.69, respectively). The miRNA-378 expression profile was significantly higher in T1D patients compared with the controls (P<0.05). Lower miRNA-378 expression in prepubertal controls was observed compared to pubertal controls, prepubertal T1D, and pubertal T1D (P<0.05). AntiGAD65, AntilA2, and AntiZnT8 were positively correlated with miRNA-378 (P=0.002, P=0.053, and P=0.007). No statistically significant correlation was observed between miRNA-378 expression and IL-6, TNF-α, or body fat. Conclusion: Elevated miRNA-378 expression in T1D patients compared with controls is linked to pubertal stage but is not associated with proinflammatory status or body composition.

NEW PROCEDURE TO ESTIMATE THE BRAKE WARPING IN A ROLLER TESTER

D. GARCÍA-POZUELO RAMOS,A. GAUCHÍA,B. L. BOADA,V. DÍAZ 한국자동차공학회 2010 International journal of automotive technology Vol.11 No.5

Vehicle systems such as the steering, brakes and suspension greatly influence vehicle safety. Therefore, these systems must be inspected to guarantee that they are functioning correctly and to certify that the vehicle is functioning at a satisfactory safety level. In disc brakes, warping is one of the principal reasons for vibrations and noise, and it contributes to diminished brake efficiency. Currently, the International Motor Vehicle Inspection Committee (CITA) demands disc brake warping inspections occur during periodic motor vehicle inspections (PMVIs); however, the procedure to carry out this inspection is not well defined. In this investigation, the warping phenomenon has been analyzed, and a new inspection procedure is proposed.

Asymptotic behavior of grafting rays

Dí,az, Raquel,Kim, Inkang Springer-Verlag 2012 Geometriae dedicata Vol.158 No.1

Multivisceral resection for colonic splenic flexure malakoplakia: a case report of a minimally invasive approach

Díaz Andrés Ramiro Lanza,Pezet Santiago Gallardo,González Osvaldo Soto,Trueba Montserrat Guraieb,Alonso Ivan Azael Martínez,Ramirez Mario Alberto López 대한대장항문학회 2023 Annals of Coloproctolgy Vol.39 No.2

Malakoplakia is a rare granulomatous inflammatory disorder. Its diagnosis depends on histopathological findings; however, high-quality literature regarding proper medical/surgical treatment is lacking. A 38-year-old diabetic female patient was admitted to the emergency room with a history of lower gastrointestinal hemorrhage. Colonoscopy revealed a lesion in the descending colon, and abdominal computed tomography revealed a splenic flexure mass involving the lower pole of the spleen and upper pole of the left kidney. Biopsies confirmed the diagnosis of malakoplakia. After completing antibiotic treatment, a restaging computed tomography revealed a discrete mass increase; hence, the patient underwent laparoscopic <i>en bloc</i> colectomy and partial nephrectomy. Postoperatively, the patient developed a pancreatic fistula, which was successfully treated with percutaneous drainage and antibiotics. The presence of pathognomonic Michaelis-Gutmann inclusions on histopathology is frequently reported as the key to diagnosing malakoplakia. Herein, we present a successful, minimally invasive surgical treatment for colonic malakoplakia.

Evaluation of the Mechanical and Fire Resistance Properties ofRigid Tannin Polyurethane Foams with Copper Oxide Nanoparticles

Andrés Díaz-Gomez,Mytzy Godoy,María Elizabeth Berrio,Jesús Ramirez,Andrés Felipe Jaramillo,Carlos Medina,Mary Montaño,Manuel Francisco Meléndrez 한국섬유공학회 2022 Fibers and polymers Vol.23 No.7

In this study, a polymerized polyurethane foam was formulated from tannins extracted from Pinus radiata aspolyol, and copper oxide nanoparticles (CuO-NPs) at a concentration of 2 % w/w as a nucleating agent. This produced areinforced foam with better mechanical properties and fire resistance. The impact of the addition of CuO-NPs on themechanical and thermal properties of the tannin foam was also studied. The properties studied were foaming process, foamdensity, cell morphology, flammability and thermal conductivity. The results revealed that the CuO-NPs incorporated in thefoam formulation act as nucleation centers, which decrease the pore size, strengthen the cell walls, and improve mechanicalproperties. The tannin samples showed good thermal resistance performance with a limit oxygen index (LOI) higher than21 %. The results obtained were contrasted with two foams, a commercial foam (SoudaFoam) and a foam generated with thesame dissociate, but with a commercial polyol (LHT-112). The foam with NPs had an elastic modulus of 3.7 MPa and stress(max) of 1.13 MPa, which was higher than those of the foams used as controls.

Structural and optical characterization of wurtzite type ZnS

J. Díaz-Reyes,R.S. Castillo-Ojeda,R. Sánchez-Espíndola,M. Galván-Arellano,O. Zaca-Morán 한국물리학회 2015 Current Applied Physics Vol.15 No.2

ZnS films were grown on (001) GaAs substrates at different temperatures by RF magnetron sputtering. The ZnS chemical stoichiometry was determined by Energy-dispersive X-ray spectroscopy (EDS), besides it allowed to find the residual impurities, mainly oxygen. The X-ray diffraction (XRD) analysis and Raman scattering reveal that ZnS deposited thin films showed hexagonal wurtzite crystalline phase. The films average crystallite size range was from 8.15 to 31.95 nm, which was determined using the Debye eScherrer equation for the peak W(101). Besides an experimental study of first- and second-order Raman scattering of ZnS films is made. An energy level diagram involving oxygen traps and interstitial sulphur ions is used to explain the origin of the radiative transitions observed in the room temperature photoluminescence (PL) spectra.

A back to the city movement by local government action: gentrification in Spain and Latin America

Ibán Díaz-Parra 서울시립대학교 도시과학연구원 2015 도시과학국제저널 Vol.19 No.3

Studies on gentrification in Spain and Latin America have been proliferating rapidly in recent years. It has provoked debates on the applicability of the concept and the particular characteristics that the process takes. In this context, the study looks at the transformation of city centres in Spain and Latin America through various case studies in which the use of the concept of gentrification is advocated, while drawing attention to the notable differences in the urban, social and economic spheres between these cases and the ones studied in English-speaking countries. Specifically, a key feature is claimed to be the primacy of state intervention as a catalyst of the process, so that gentrification in this region can be understood as a return to the city of local government action.