Advances in surface design and biomedical applications of magnetic nanoparticles.

Despite significant efforts by scientists in the development of advanced nanotechnology materials for smart diagnosis devices and drug delivery systems, the success of clinical trials remains largely elusive. In order to address this biomedical challenge, magnetic nanoparticles (MNPs) have gained attention as a promising candidate due to their theranostic properties, which allow the simultaneous treatment and diagnosis of a disease. Moreover, MNPs have advantageous characteristics such as a larger surface area, high surface-to-volume ratio, enhanced mobility, mass transference and, more notably, easy manipulation under external magnetic fields. Besides, certain magnetic particle types based on the magnetite (Fe3O4) phase have already been FDA-approved, demonstrating biocompatible and low toxicity. Typically, surface modification and/or functional group conjugation are required to prevent oxidation and particle aggregation. A wide range of inorganic and organic molecules have been utilized to coat the surface of MNPs, including surfactants, antibodies, synthetic and natural polymers, silica, metals, and various other substances. Furthermore, various strategies have been developed for the synthesis and surface functionalization of MNPs to enhance their colloidal stability, biocompatibility, good response to an external magnetic field, etc. Both uncoated MNPs and those coated with inorganic and organic compounds exhibit versatility, making them suitable for a range of applications such as drug delivery systems (DDS), magnetic hyperthermia, fluorescent biological labels, biodetection and magnetic resonance imaging (MRI). Thus, this review provides an update of recently published MNPs works, providing a current discussion regarding their strategies of synthesis and surface modifications, biomedical applications, and perspectives.

Ultrafast sonochemistry-based approach to coat TiO2 commercial particles for sunscreen formulation.

TiO2 is a common inorganic filter used in sunscreens due to its photoprotective effect on the skin against UV radiation. However, the use of this kind of material in cosmetics is limited by its inherent photocatalytic activity. It is known that coating on TiO2 surface can improve some features. Although, many of the methodologies used for this purpose are still laborious and time-consuming. Thus, this work reports a novel, easy, cheap and fast strategy to coat TiO2 particles by using a sonochemistry approach, aiming to decrease photocatalytic activity and to enhance colloidal stability. For this proposal, SiO2, Al2O3, ZrO2 and sodium polyacrylate (PAANa) were used to tune the surface of commercial TiO2 particles and they were applied in a sunscreen formulation. The samples were characterized by XRPD, FT-IR, DLS, EDS, SEM and TEM. The photocatalytic activity and UV-shielding ability were also evaluated. The sunscreen formulations were prepared and characterized by zeta potential, DLS, and Sun Protection Factor (SPF). FT-IR, EDS, and charge surface of the particles confirmed the success of the sonochemistry coating. Additionally, TiO2@Al2O3, TiO2@SiO2 and TiO2@PAANa show a lower photocatalytic activity than original TiO2 with similar UV-shielding ability. The sunscreens produced with the coated TiO2 have similar SPF to the one with commercial TiO2. Specifically, the sunscreen with TiO2@PAANa shows an increase in colloidal stability. Herein, the incorporation of the sonochemical-coated TiO2 particles in sunscreen formulations may produce sunscreens with better aesthetic appearance and a greater health security due to its lower free radicals production.

[Phonoaudiology in public health]. / Fonoaudiologia em saúde pública.

An undestanding of the activities and functions of a speech therapist within the specific context of the Basic Health Units (Unidades Básicas de Saúde) is sought. Difficulties relating to the introduction of a new service on the basis of one of the health professions that has not hitherto belonged to the group of categories which are traditionally incorporated in these same Basic Units. When the statistical data on the demand for speech therapy services by the population who attend health centres were considered, it was discovered that 32% were of schooling age and had been referred by schools, allegedly due to "learning problems". Closer contact with these children, through speech therapy, has brought a different aspect to light i.e. that one cannot consider as disturbance/deviation/problem/pathology written signs which constitute indications of the shock between the process of literacy and that of learning how to read and write. To understand the problem from the point of view of public health, a programme of teacher counselling is proposed, with the purpose of helping the school to clarify its role as co-constructor of the child's literacy process and of returning to the teacher the responsibility for the success and/or failure of teaching how to read and write. A similar programme is proposed for creches where coincidently, a greater proportion (44%) of the younger children (2 to 5 years of age) are seen to have difficulties in oral language development.(ABSTRACT TRUNCATED AT 250 WORDS)