162 research outputs found
"Eu sou a sobrevivente do que você joga fora" ou, os processos de subjetivação no trabalho de catação
A Coarse-grained Model for Aqueous Two-phase Systems: Application to Ferrofluids
Aqueous two-phase systems (ATPSs), that is, phase-separating solutions of
water soluble but mutually immiscible molecular species, offer fascinating
prospects for selective partitioning, purification, and extraction. Here, we
formulate a general Brownian dynamics based coarse-grained simulation model for
a polymeric ATPS comprising two water soluble but mutually immiscible polymer
species. A third solute species, representing, e.g., nanoparticles (NPs),
additional macromolecular species, or impurities can readily be incorporated
into the model. We demonstrate that the model captures satisfactorily the phase
separation, partitioning, and interfacial properties of a model ATPS composed
of a polymer mixture of dextran and polyethylene glycol (PEG) in which magnetic
NPs selectively partition into one of the two polymeric phases. The NP
partitioning is characterized both via the computational model and
experimentally under different conditions. The simulation model captures the
trends observed in the experiments and quantitatively links the partitioning
behavior to the component species interactions. Finally, the response of the
simulation model to external magnetic field, with the magnetic NPs as the
additional partitioned component, shows that the ATPS interface fluctuations
can be controlled by the magnetic field at length scales much smaller than
those probed experimentally to date
Nanoscale characterization of an all-oxide core-shell nanorod heterojunction using intermodulation atomic force microscopy (AFM) methods
The electrical properties of an all-oxide core-shell ZnO-Co3O4nanorod heterojunction were studied in the dark and under UV-vis illumination. The contact potential difference and current distribution maps were obtained utilizing new methods in dynamic multifrequency atomic force microscopy (AFM) such as electrostatic and conductive intermodulation AFM. Light irradiation modified the electrical properties of the nanorod heterojunction. The new techniques are able to follow the instantaneous local variation of the photocurrent, giving a two-dimensional (2D) map of the current-voltage curves and correlating the electrical and morphological features of the heterostructured core-shell nanorods
Microwave driven synthesis of narrow bandgap alpha-tin nanoparticles on silicon
This work proposes a microwave-based synthetic route for the preparation of tin nanospheres with a diamond-like a-phase structure on silicon. The main characteristics of the synthesized material are an extraordinarily narrow (around 50 meV) direct bandgap and an improved thermal stability (up to 200° C). Structural and compositional characterizations showed a core–shell structure comprised of an outer amorphous oxide shell and inner core containing a-phase tin domains. Microwaves turned out to be instrumental in achieving the specific nanostructures reported, due to their peculiar heating characteristics. Low pressure, low temperature and compatibility with integrated circuits manufacturing represent the most innovative features of the present synthetic process
Male breast cancer
Male breast cancer (MBC) is a rare disease representing less than 1% of all breast cancers (BC) and less than 1% of cancers in men. Age at presentation is mostly in the late 60s. MBC is recognized as an estrogen-driven disease, specifically related to hyperestrogenism. About 20% of MBC patients have family history for BC. Mutations in BRCA1 and, predominantly, BRCA2, account for approximately 10% of MBC cases.
Because of its rarity, MBC is often compared with female BC (FBC). Based on age-frequency distribution, age-specific incidence rate patterns and prognostic factors profiles, MBC is considered similar to late-onset, postmenopausal estrogen/progesterone receptor positive (ER+/PR+) FBC. However, clinical and pathological characteristics of MBC do not exactly overlap FBC. Compared with FBC, MBC has been reported to occur later in life, present at a higher stage, and display lower histologic grade, with a higher proportion of ER+ and PR+ tumors.
Although rare, MBC remains a substantial cause for morbidity and mortality in men, probably because of its occurrence in advanced age and delayed diagnosis. Diagnosis and treatment of MBC generally is similar to that of FBC. Men tend to be treated with mastectomy rather than breast-conserving surgery. The backbone of adjuvant therapy or palliative treatment for advanced disease is endocrine, mostly tamoxifen.
Use of FBC-based therapy led to the observation that treatment outcomes for MBC are worse and that survival rates for MBC do not improve like FBC. These different outcomes may suggest a non-appropriate utilization of treatments and that different underlying pathogenetic mechanisms may exist between male and female BC
Developmental and Tumor Angiogenesis Requires the Mitochondria-Shaping Protein Opa1
While endothelial cell (EC) function is influenced by mitochondrial metabolism, the role of mitochondrial dynamics in angiogenesis, the formation of new blood vessels from existing vasculature, is unknown. Here we show that the inner mitochondrial membrane mitochondrial fusion protein optic atrophy 1 (OPA1) is required for angiogenesis. In response to angiogenic stimuli, OPA1 levels rapidly increase to limit nuclear factor kappa-light-chain-enhancer of activated B cell (NFκB) signaling, ultimately allowing angiogenic genes expression and angiogenesis. Endothelial Opa1 is indeed required in an NFκB-dependent pathway essential for developmental and tumor angiogenesis, impacting tumor growth and metastatization. A first-in-class small molecule-specific OPA1 inhibitor confirms that EC Opa1 can be pharmacologically targeted to curtail tumor growth. Our data identify Opa1 as a crucial component of physiological and tumor angiogenesis
Mapeando programas de redução de danos da Região Metropolitana de Porto Alegre, Rio Grande do Sul, Brasil
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