MXene-Based Nanocomposites for Piezoelectric and Triboelectric Energy Harvesting Applications.

Due to its superior advantages in terms of electronegativity, metallic conductivity, mechanical flexibility, customizable surface chemistry, etc., 2D MXenes for nanogenerators have demonstrated significant progress. In order to push scientific design strategies for the practical application of nanogenerators from the viewpoints of the basic aspect and recent advancements, this systematic review covers the most recent developments of MXenes for nanogenerators in its first section. In the second section, the importance of renewable energy and an introduction to nanogenerators, major classifications, and their working principles are discussed. At the end of this section, various materials used for energy harvesting and frequent combos of MXene with other active materials are described in detail together with the essential framework of nanogenerators. In the third, fourth, and fifth sections, the materials used for nanogenerators, MXene synthesis along with its properties, and MXene nanocomposites with polymeric materials are discussed in detail with the recent progress and challenges for their use in nanogenerator applications. In the sixth section, a thorough discussion of the design strategies and internal improvement mechanisms of MXenes and the composite materials for nanogenerators with 3D printing technologies are presented. Finally, we summarize the key points discussed throughout this review and discuss some thoughts on potential approaches for nanocomposite materials based on MXenes that could be used in nanogenerators for better performance.

ZnO/Graphene Composite from Solvent-Exfoliated Few-Layer Graphene Nanosheets for Photocatalytic Dye Degradation under Sunlight Irradiation.

ZnO/graphene nanocomposites were prepared using a facile approach. Graphene nanosheets were prepared by ultrasonication-based liquid phase exfoliation of graphite powder in a low boiling point organic solvent, 1,2-Dichloroethane, for the preparation of ZnO/graphene nanocomposites. Structural properties of the synthesized ZnO/graphene nanocomposites were studied through powder XRD and micro-Raman analysis. The characteristic Raman active modes of ZnO and graphene present in the micro-Raman spectra ensured the formation of ZnO/graphene nanocomposite and it is inferred that the graphene sheets in the composites were few layers in nature. Increasing the concentration of graphene influenced the surface morphology of the ZnO nanoparticles and a flower shape ZnO was formed on the graphene nanosheets of the composite with high graphene concentration. The efficiencies of the samples for the photocatalytic degradation of Methylene Blue dye under sunlight irradiation were investigated and 97% degradation efficiency was observed. The stability of the nanocomposites was evaluated by performing five cycles, and 92% degradation efficiency was maintained. The observed results were compared with that of ZnO/graphene composite derived from other methods.

MXene/Ferrite Magnetic Nanocomposites for Electrochemical Supercapacitor Applications.

MXene has been identified as a new emerging material for various applications including energy storage, electronics, and bio-related due to its wider physicochemical characteristics. Further the formation of hybrid composites of MXene with other materials makes them interesting to utilize in multifunctional applications. The selection of magnetic nanomaterials for the formation of nanocomposite with MXene would be interesting for the utilization of magnetic characteristics along with MXene. However, the selection of the magnetic nanomaterials is important, as the magnetic characteristics of the ferrites vary with the stoichiometric composition of metal ions, particle shape and size. The selection of the electrolyte is also important for electrochemical energy storage applications, as the electrolyte could influence the electrochemical performance. Further, the external magnetic field also could influence the electrochemical performance. This review briefly discusses the synthesis method of MXene, and ferrite magnetic nanoparticles and their composite formation. We also discussed the recent progress made on the MXene/ferrite nanocomposite for potential applications in electrochemical supercapacitor applications. The possibility of magnetic field-assisted supercapacitor applications with electrolyte and electrode materials are discussed.

Directed sibling donor cord blood donation in the Chilean Public Health System. / Donación dirigida de sangre de Cordón Umbilical de Hermano Compatible en el Sistema de Salud Público de Chile.

INTRODUCTION: Cord blood (CB) as a source of Hematopoietic Stem Cells for Transplantation (HSCT) is well established. Worldwide, nonetheless, less than 10% of the CB HSCTs are performed with a match sibling donor. Since 2004, the Chilean National Childhood Cancer Program (PINDA) net work, has established a CB directed donation program for HSCT. PATIENTS AND METHOD: An obser vational, descriptive and retrospective study was designed to assess the number and characteristics of the CB units collected in the program as well as the number, clinical characteristics and follow-up of the patients who received an HSCT from those CB units between January 2004 and October 2018. RESULTS: Sixty CB units have been collected; 55 of them with full records and stored. The median volume collected was 74.8 ml (30.0-170.8), the median number of total nucleated cells was 7.6 x 10e8 (2.0-21.1), and the median of CD34+ cells was 1.6 x 10e6 (0.2-11.6). Four high-risk leukemia patients received HSCT, all of them developed severe complications after transplantation and one patient died due to relapse. Those patients currently alive have a 100% Karnofsky/Lansky score. The median follow-up time was 8 years. CONCLUSION: The PINDA program has allowed 4 patients to be transplan ted who otherwise would not have had access to a donor. This directed donation program could be seen as a model for the development of a public cord blood bank in Chile.

Donación dirigida de sangre de Cordón Umbilical de Hermano Compatible en el Sistema de Salud Público de Chile / Directed sibling donor cord blood donation in the Chilean Public Health System

Resumen: Introducción: La sangre de cordón umbilical (SCU) como fuente para trasplante de células proge- nitoras hematopoyéticas (TPH) está bien establecida. Internacionalmente, menos del 10% de los TPH de SCU corresponde a donantes hermanos compatibles. Dentro de la red del Programa Infantil Nacional de Drogas Antineoplásicas (PINDA), existe desde enero 2004 un programa de donación dirigida de SCU para TPH. Pacientes y Método: Se diseñó un estudio observacional, retrospectivo, descriptivo, se revisaron el número y características de las unidades de SCU recolectadas en el PINDA y el número, características y evolución de los pacientes trasplantados con esas unidades entre enero de 2004 y octubre de 2018. Resultados: Sesenta unidades de SCU han sido recolectadas, de ellas 55 con registro completo. La mediana de volumen de las unidades almacenadas fue 74,8 ml (30,0-170,8), la mediana de células nucleadas totales 7,6 x 10e8 (2,0-21,1), mediana de células CD34+ 1,6 x 10e6 (0,2-11,6). Cuatro pacientes con leucemias de alto riesgo fueron trasplantados; mediana de segui miento es de 8 años. Todos desarrollaron complicaciones severas post TPH, uno de ellos falleció de recaída y los tres actualmente vivos presentan un Karnofsky/Lansky 100%. Conclusión: El programa ha permitido el trasplante de 4 pacientes que de otro modo no habrían tenido acceso a un donante. Este programa de donación dirigida puede ser considerado una primera etapa para el desarrollo de un banco público de sangre de cordón umbilical en Chile.

Abstract: Introduction: Cord blood (CB) as a source of Hematopoietic Stem Cells for Transplantation (HSCT) is well established. Worldwide, nonetheless, less than 10% of the CB HSCTs are performed with a match sibling donor. Since 2004, the Chilean National Childhood Cancer Program (PINDA) net work, has established a CB directed donation program for HSCT. Patients and Method: An obser vational, descriptive and retrospective study was designed to assess the number and characteristics of the CB units collected in the program as well as the number, clinical characteristics and follow-up of the patients who received an HSCT from those CB units between January 2004 and October 2018. Results: Sixty CB units have been collected; 55 of them with full records and stored. The median volume collected was 74.8 ml (30.0-170.8), the median number of total nucleated cells was 7.6 x 10e8 (2.0-21.1), and the median of CD34+ cells was 1.6 x 10e6 (0.2-11.6). Four high-risk leukemia patients received HSCT, all of them developed severe complications after transplantation and one patient died due to relapse. Those patients currently alive have a 100% Karnofsky/Lansky score. The median follow-up time was 8 years. Conclusion: The PINDA program has allowed 4 patients to be transplan ted who otherwise would not have had access to a donor. This directed donation program could be seen as a model for the development of a public cord blood bank in Chile.

[Hypovitaminosis D in pediatric patients on renal replacement therapy]. / Hipovitaminosis D en pacientes pediátricos en terapia de sustitución renal.

BACKGROUND: Hypovitaminosis D has a high prevalence among patients with chronic kidney disease (CKD). AIM: To determine the prevalence of 25 hydroxy vitamin D (25(OH) D) insufficiency and deficiency in pediatric patients on dialysis and kidney transplantation. MATERIAL AND METHODS: Serum calcium and phosphorus, parathormone (PTH), alkaline phosphatases and 25 (OH)D were measured in 13 children on hemodialysis (HD), 18 on peritoneal dialysis (PD) and 53 that received an allograft (Tx), aged 9.8 ± 4.6 years (51% females). RESULTS: Fifty four percent of patients had height Z score less than -1.88. Patients on HD had the lowest values. The average time of replacement therapy was 2.9 ± 2.8 years. Mean 25(OH)D levels in all was 18.7 ± 10.7ng/ml (HD: 21 ± 16.8, PD: 18.9 ± 8.5, Tx: 18.1 ± 9.72 ng/ml). Eighty eight percent of patients had levels below 30 ng/ml. Mean of serum calcium was 9.5 ± 0.64 mg/dl, serum phosphorus 5.03 ± 1.02 mg/dl, calcium-phosphorus product 48 ± 11.8 mg/dl and alkaline phosphatases 300.5 ± 171.3 IU/L. Average PTH values in dialyzed and Tx patients were 724.6 ± 640.5 and 107.7 ± 56.2 pg/ml, respectively (p < 0.001). A positive correlation between 25 (OH) D and calcium levels among PD patients was observed (r = 0.490, p = 0.04). CONCLUSIONS: Hypovitaminosis D is highly prevalent among children on renal substitution therapy, regardless of the type of therapy used and the stage of renal failure.

Hipovitaminosis D en pacientes pediátricos en terapia de sustitución renal / Hypovitaminosis D in pediatric patients on renal replacement therapy

Background: Hypovitaminosis D has a high prevalence among patients with chronic kidney disease (CKD). Aim: To determine the prevalence of 25 hydroxy vitamin D (25(OH) D) insufficiency and deficiency in pediatric patients on dialysis and kidney transplantation. Material and Methods: Serum calcium and phosphorus, parathormone (PTH), alkaline phosphatases and 25 (OH)D were measured in 13 children on hemodialysis (HD), 18 on peritoneal dialysis (PD) and 53 that received an allograft (Tx), aged 9.8 ± 4.6 years (51 percent females). Results: Fifty four percent of patients had height Z score less than -1.88. Patients on HD had the lowest values. The average time of replacement therapy was 2.9 ± 2.8 years. Mean 25(OH)D levels in all was 18.7 ± 10.7ng/ml (HD: 21 ± 16.8, PD: 18.9 ± 8.5, Tx: 18.1 ± 9.72 ng/ml). Eighty eight percent of patients had levels below 30 ng/ml. Mean of serum calcium was 9.5 ± 0.64 mg/dl, serum phosphorus 5.03 ± 1.02 mg/dl, calcium-phosphorus product 48 ± 11.8 mg/dl and alkaline phosphatases 300.5 ± 171.3 IU/L. Average PTH values in dialyzed and Tx patients were 724.6 ± 640.5 and 107.7 ± 56.2 pg/ml, respectively (p < 0.001). A positive correlation between 25 (OH) D and calcium levels among PD patients was observed (r = 0.490, p = 0.04). Conclusions: Hypovitaminosis D is highly prevalent among children on renal substitution therapy, regardless of the type of therapy used and the stage of renal failure.