Preparation and crystallization of hollow α-Fe<inf>2</inf>O<inf>3</inf> microspheres following the gas-bubble template method

In this work we report the formation of hollow α-Fe2O3 (hematite) microspheres by the gas-bubble template method. This technique is simple and it does not require hard templates, surfactants, special conditions of atmosphere or complex steps. After reacting Fe(NO3)3.9H2O and citric acid in water by sol-gel, the precursor was annealed in air at different temperatures between 180 and 600 ºC. Annealing at 550 and 600 ºC generates bubbles on the melt which crystallize and oxidizes to form hematite hollow spheres after condensation. The morphology and crystal evolution are studied by means of X-ray diffraction and scanning electron microscopy. We found that after annealing at 250-400 ºC, the sample consist of a mixture of magnetite, maghemite and hematite. Single hematite phase in the form of hollow microspheres is obtained after annealing at 500 and 600 ºC. The crystallization and crystal size of the hematite shells increase with annealing temperature. A possible mechanism for hollow sphere formation is presented.This work was supported by the Engineering and Physical Science Research Council (EPSRC No. EP/J003638/1). The work in Peru has been supported by CONCYTEC. The work in Brazil was supported by CNPq (307552/2012-8), CAPES (PNPD- 230.007518/2011-11) and FACEPE (APQ-0589-1.05/08).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.matchemphys.2015.11.02

Telecardiology and Remote Monitoring of Implanted Electrical Devices: The Potential for Fresh Clinical Care Perspectives

Telecardiology may help confront the growing burden of monitoring the reliability of implantable defibrillators/pacemakers. Herein, we suggest that the evolving capabilities of implanted devices to monitor patients’ status (heart rhythm, fluid overload, right ventricular pressure, oximetry, etc.) may imply a shift from strictly device-centered follow-up to perspectives centered on the patient (and patient-device interactions). Such approaches could provide improvements in health care delivery and clinical outcomes, especially in the field of heart failure. Major professional, policy, and ethical issues will have to be overcome to enable real-world implementation. This challenge may be relevant for the evolution of our health care systems

Tracking the turnover of SARS-CoV-2 VOCs gamma to delta in a Brazilian state (Minas Gerais) with a high-vaccination status

The emergence and global dissemination of Severe Acute Respiratory Syndrome virus 2 (SARS-CoV-2) variants of concern (VOCs) have been described as the main factor driving the Coronavirus Disease 2019 pandemic. In Brazil, the Gamma variant dominated the epidemiological scenario during the first period of 2021. Many Brazilian regions detected the Delta variant after its first description and documented its spread. To monitor the introduction and spread of VOC Delta, we performed Polymerase Chain Reaction (PCR) genotyping and genome sequencing in ten regional sentinel units from June to October 2021 in the State of Minas Gerais (MG). We documented the introduction and spread of Delta, comprising 70 per cent of the cases 8 weeks later. Comparing the viral loads of the Gamma and Delta dominance periods, we provide additional evidence that the latter is more transmissible. The spread and dominance of Delta did not culminate in the increase in cases and deaths, suggesting that the vaccination may have restrained the epidemic growth. Analysis of 224 novel Delta genomes revealed that Rio de Janeiro state was the primary source for disseminating this variant in the state of MG. We present the establishment of Delta, providing evidence of its enhanced transmissibility and showing that this variant shift did not aggravate the epidemiological scenario in a high immunity setting

NBER WORKING PAPER SERIES THE CORRELATION OF WEALTH ACROSS GENERATIONS

We thank Heidi Shierholz for excellent research assistance and participants at the NBER 200