Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

Evolution and epidemic spread of SARS-CoV-2 in Brazil.

Abstract: Brazil currently has one of the fastest-growing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemics in the world. Because of limited available data, assessments of the impact of nonpharmaceutical interventions (NPIs) on this virus spread remain challenging. Using a mobility-driven transmission model, we show that NPIs reduced the reproduction number from >3 to 1 to 1.6 in Sao Paulo and Rio de Janeiro. Sequencing of 427 new genomes and analysis of a geographically representative genomic dataset identified >100 international virus introductions in Brazil. We estimate that most (76%) of the Brazilian strains fell in three clades that were introduced from Europe between 22 February and 11 March 2020. During the early epidemic phase, we found that SARS-CoV-2 spread mostly locally and within state borders. After this period, despite sharp decreases in air travel, we estimated multiple exportations from large urban centers that coincided with a 25% increase in average traveled distances in national flights. This study sheds new light on the epidemic transmission and evolutionary trajectories of SARS-CoV-2 lineages in Brazil and provides evidence that current interventions remain insufficient to keep virus transmission under control in this country.

Fresh versus elective frozen embryo transfer in IVF/ICSI cycles: a systematic review and meta-analysis of reproductive outcomes.

Abstract: Background Elective freezing of all good quality embryos and transfer in subsequent cycles, i.e. elective frozen embryo transfer (eFET), has recently increased significantly with the introduction of the GnRH agonist trigger protocol and improvements in cryo-techniques. The ongoing discussion focuses on whether eFET should be offered to the overall IVF population or only to specific subsets of patients. Until recently, the clinical usage of eFET was supported by only a few randomized controlled trials (RCT) and meta-analyses, suggesting that the eFET not only reduced ovarian hyperstimulation syndrome (OHSS), but also improved reproductive outcomes. However, the evidence is not unequivocal, and recent RCTs challenge the use of eFET for the general IVF population. Objective and rationale This systematic review and meta-analysis aimed at evaluating whether eFET is advantageous for reproductive, obstetric and perinatal outcomes compared with fresh embryo transfer in IVF/ICSI cycles. Additionally, we evaluated the effectiveness of eFET in comparison to fresh embryo transfer in different subgroups of patients undergoing IVF/ICSI cycles. Search methods We conducted a systematic review, using PubMed/Medline and EMBASE to identify all relevant RCTs published until March 2018. The participants included infertile couples undergoing IVF/ICSI with or without preimplantation genetic testing for aneuploidy (PGT-A). The primary outcome was the live birth rate (LBR), whereas secondary outcomes were cumulative LBR, implantation rate, miscarriage, OHSS, ectopic pregnancy, preterm birth, pregnancy-induced hypertension, pre-eclampsia, mean birthweight and congenital anomalies. Subgroup analyses included normal and hyper-responder patients, embryo developmental stage on the day of embryo transfer, freezing method and the route of progesterone administration for luteal phase support in eFET cycles. Outcomes Eleven studies, including 5379 patients, fulfilling the inclusion criteria were subjected to qualitative and quantitative analysis. A significant increase in LBR was noted with eFET compared with fresh embryo transfer in the overall IVF/ICSI population [risk ratio (RR) = 1.12; 95% CI: 1.01-1.24]. Subgroup analyses indicated higher LBRs by eFET than by fresh embryo transfer in hyper-responders (RR = 1.16; 95% CI: 1.05-1.28) and in PGT-A cycles (RR = 1.55; 95% CI: 1.14-2.10). However, no differences were observed for LBR in normo-responders (RR = 1.03; 95% CI: 0.91-1.17); moreover, the cumulative LBR was not significantly different in the overall population (RR = 1.04; 95% CI: 0.97-1.11). Regarding safety, the risk of moderate/severe OHSS was significantly lower with eFET than with fresh embryo transfer (RR = 0.42; 95% CI: 0.19-0.96). In contrast, the risk of pre-eclampsia increased with eFET (RR = 1.79; 95% CI: 1.03-3.09). No statistical differences were noted in the remaining secondary outcomes. Wider implications Although the use of eFET has steadily increased in recent years, a significant increase in LBR with eFET was solely noted in hyper-responders and in patients undergoing PGT-A. Concerning safety, eFET significantly decreases the risk of moderate and severe OHSS, albeit at the expense of an increased risk of pre-eclampsia.

Specific stabilisation exercise for spinal and pelvic pain: a systematic review

Abstract: The aim of this study was to conduct a systematic review of the efficacy of specific stabilisation exercise for spinal and pelvic pain. Randomised clinical trials evaluating specific stabilisation exercise were identified and retrieved. Outcomes were disability, pain, return to work, number of episodes, global perceived effect, or health-related quality of life. A single trial reported that specific stabilisation exercise was more effective than no treatment but not more effective than spinal manipulative therapy for the management of cervicogenic headache and associated neck pain. Single trials reported that specific stabilisation exercise was effective for pelvic pain and for prevention of recurrence after an acute episode of low back pain but not to reduce pain or disability associated with acute low back pain. Pooled analyses revealed that, for chronic low back pain, specific stabilisation exercise was superior to usual medical care and education but not to manipulative therapy, and no additional effect was found when specific stabilisation exercise was added to a conventional physiotherapy program. A single trial reported that specific stabilisation exercise and a surgical procedure to reduce pain and disability in chronic low back pain were equally effective. The available evidence suggests that specific stabilisation exercise is effective in reducing pain and disability in chronic but not acute low back pain. Single trials indicate that specific stabilisation exercise can be helpful in the treatment of cervicogenic headache and associated neck pain, pelvic pain, and in reducing recurrence after acute low back pain.

Third and fourth optical transitions in semiconducting carbon nanotubes.

Abstract: We have studied the optical transition energies of single-wall carbon nanotubes over broad diameter (0.7–2.3 nm) and energy (1.26 –2.71 eV) ranges, using their radial breathing mode Raman spectra. We establish the diameter and chiral angle dependence of the poorly studied third and fourth optical transitions in semiconducting tubes. Comparative analysis between the higher lying transitions and the first and second transitions show two different diameter scalings. Quantum mechanical calculations explain the result showing strongly bound excitons in the first and second transitions and a delocalized electron wave function in the third transition. In carbon nanotubes [1], quantum confinement is responsible for 1D van Hove singularities in the electronic density of states and unusually strong many-body (electron-electron and electron-hole) interactions [2]. Current understanding of the photophysical properties of semiconducting carbon nanotubes [2 –7] are based mostly on experimental results for the first (E S ) and second (E S ) optical transitions (S superscript stands for semiconducting, while M will be used for metallic tubes), based on a set of fewer than 40 SWNTs (characterized by their (n, m) indices [1]) in the diameter range from 0.7 to 1.3 nm [8– 13]. Efforts have been made to extend these results to larger diameter tubes, and to establish the third (E S ) and fourth (E S ) transitions [14,15]. E S and E S are important for the optics of large diameter semiconducting single-wall carbon nanotubes (SWNTs), since for dt > 1: 3n m, E S is already in the infrared range [8–11]. Here we measure the optical properties of SWNTs over broad diameter (0.7–2.3 nm) and energy (1.26 –2.71 eV) ranges. We probe over 200 different SWNT species, about 378 different optical transition energies, going up to the fourth optical transition of semiconducting SWNTs, thus establishing the (n, m) dependence of the poorly studied E S and E S transitions. Surprisingly, we find that E S and E S follow a different (blue-shifted) diameter scaling when compared with E S and E S . These results are supported by electronic structure calculations showing that E S and E S are described by bound exciton states, whereas the E S transitions correspond to a delocalized exciton or to an unbound electron-hole pair. The sample consists of as-grown vertically aligned SWNTs, synthesized by the chemical vapor deposition method from alcohol, on top of a quartz substrate. Transmission Electron Microscopy shows a rather homogeneous sample formed by isolated SWNTs and very small

Synthesis and characterization of poly (vinyl alcohol) hydrogels and hybrids for rMPB70 protein adsorption

Abstract: Polyvinyl alcohol (PVA), PVA crosslinked with glutaraldehyde hydrogels (PVA/GA), PVA with tetraethylorthosilicate (PVA/TEOS) and PVA/GA/TEOS hybrids with recombinant MPB70 protein (rMPB70) incorporated were chemically characterized by Fourier transform infrared spectroscopy (FTIR). FTIR spectra of PVA hydrogel samples showed the absorption regions of the specific chemical groups associated with poly(vinyl alcohol) (-OH, -CO, -CH2) and PVA/GA confirming the formation of crosslinked hydrogel (duplet -CH). It was observed C-H broad alkyl stretching band (n = 2850-3000 cm-1) and typical strong hydroxyl bands for free alcohol (nonbonded -OH stretching band at n = 3600-3650 cm-1), and hydrogen bonded band (n = 3200-3570 cm-1). The most important vibration bands related to silane alcoxides have been verified on FTIR spectra of PVA/TEOS and PVA/GA/TEOS hybrids (Si-O-Si, n = 1080 and n = 450 cm-1; Si-OH, n = 950 cm-1). FTIR spectra of f PVA hydrogel with rMPB70 incorporated have indicated the specific groups usually found in protein structures, such as amides I, II and III, at 1680-1620 cm-1, 1580-1480 cm-1 and 1246 cm-1, respectively. These results have given strong evidence that recombinant protein rMPB70 was successfully adsorbed in the hydrogels and hybrids networks. These PVA based hydrogels and hybrids were further used in immunological assays (Enzyme-Linked Immunosorbent Assay - ELISA). Tests were performed to detect antibodies against rMPB70 protein in serum samples from bovines that were positive in the tuberculin test. Corresponding tests were carried out without PVA samples in microtiter plates as control. Similar results were found for commercially available microplates and PVA based hydrogels and hybrids developed in the present work regarding to immunoassay sensitivity and specificity response.