6,926 research outputs found
Increasing Accessibility to Birth Control: Over the Counter Oral Birth Control
The increasing barriers to the accessibility of birth control have prompted a need for a solution. One long standing solution suggested to diminish the barriers is by removing the prescription requirement of oral contraceptives. Removing the prescription requirement not only breaks down barriers for women without healthcare access but also allows women an opportunity to control their reproduction with more accessibility. Although this solution appears to be concise, the reality is there are many different views regarding offering birth control over the counter, including some healthcare professionals who believe the health risks outweigh the access benefit. On the contrary, those in support of removing the prescription barrier for oral contraceptives, including the American Medical Association, argue that the risks women undergo through pregnancy outweigh the risks of consuming oral contraceptives. Throughout this review article, research investigating both the advantages and disadvantages of the suggested solution is discussed assessing the potential outcomes of having oral contraceptives offered over the counter
Characterization of phytoplankton by pigment analysis and the detection of toxic cyanobacteria in reservoirs with aquaculture production
Made available in DSpace on 2018-12-11T17:19:56Z (GMT). No. of bitstreams: 0
Previous issue date: 2018-01-01The intensified use of water bodies and reservoirs for aquaculture production has increased the need for monitoring and early warning of toxins from cyanobacteria. To minimize effects from toxins, simple and fast analytical monitoring methods are crucial. Here, the content of pigments and microcystins in 14 different strains of cyanobacteria cultured under different growth conditions was investigated to determine the influence of light and nutrient starvation on pigment/ chlorophyll a (chl a) ratios. The obtained pigment/chl a ratios were applied in the software CHEMTAX to calculate the biomass of toxic cyanobacteria, as well as other phytoplankton groups. CHEMTAX ratios from the laboratory cultures were applied to water samples collected during 4 sampling periods at 6 fish farms in different reservoirs in SĂŁo Paulo State, Brazil. Cyanobacteria generally dominated in all reservoirs in all sampling periods and constituted on average 44 to 66% of the average phytoplankton biomass. The concentrations of microcystins were significantly correlated with the chl a concentrations of cyanobacteria and showed that the pigment method can be used to detect microcystin-producing cyanobacteria in these Brazilian reservoirs. When the concentration of cyanobacteria in the reservoirs was above 4 ÎŒg chl a l-1, microcystins were always detected. Our results show that pigment analysis can be used to provide fast and reliable results for the early warning, the presence and potential risk of toxic cyanobacteria in freshwater reservoirs used for aqua culture.Environment and Toxicology DHISĂŁo Paulo State Agribusiness Agency TechnologySection of Microbial Ecology and Biotechnology Department of Plant and Environmental Sciences University of CopenhagenFicology Department Botanical InstituteUNESP Campus Botucatu Institute of Biosciences Parasitology DepartmentUNESP Campus Botucatu Institute of Biosciences Parasitology Departmen
Laccase immobilization on enzymatically functionalized polyamide 6,6 fibres
Polyamide matrices, such as membranes, gels and non-wovens, have been applied as supports for enzyme immobilization, although in literature the enzyme immobilization on woven nylon matrices is rarely reported. In this work, a protocol for a Trametes hirsuta laccase immobilization using woven polyamide 6,6 (nylon) was developed. A 24 full factorial design was used to study the influence of pH, spacer (1,6-hexanediamine), enzyme and crosslinker concentration on the efficiency of immobilization. The factors enzyme dosage and spacer seem to have played a critical role in the immobilization of laccase onto nylon support. Under optimized working conditions (29 U mLâ1 of laccase, 10% of glutaraldehyde, pH = 5.5, with the presence of the spacer), the half-life time attained was about 78 h (18% higher than that of free enzyme), the protein retention was 30% and the immobilization yield was 2%. The immobilized laccase has potential for application in the continuous decolourization of textile effluents, where it can be applied into a membrane reactor
Ultrafast nonlinear optical response of Dirac fermions in graphene
The speed of solid-state electronic devices, determined by the temporal dynamics of charge
carriers, could potentially reach unprecedented petahertz frequencies through direct
manipulation by optical fields, consisting in a million-fold increase from state-of-the-art
technology. In graphene, charge carrier manipulation is facilitated by exceptionally strong
coupling to optical fields, from which stems an important back-action of photoexcited carriers.
Here we investigate the instantaneous response of graphene to ultrafast optical fields,
elucidating the role of hot carriers on sub-100 fs timescales. The measured nonlinear
response and its dependence on interaction time and field polarization reveal the back-action
of hot carriers over timescales commensurate with the optical field. An intuitive picture is
given for the carrier trajectories in response to the optical-field polarization state. We note
that the peculiar interplay between optical fields and charge carriers in graphene may also
apply to surface states in topological insulators with similar Dirac cone dispersion relations.Peer ReviewedPostprint (published version
Insecticide Resistance Mechanisms in the Green Peach Aphid Myzus persicae (Hemiptera: Aphididae) I: A Transcriptomic Survey
BACKGROUND: Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans have invested considerable effort to stay ahead of resistance phenotypes that repeatedly develop in insects. Aphids are a group of insects that have become global pests in agriculture and frequently exhibit insecticide resistance. The green peach aphid, Myzus persicae, has developed resistance to at least seventy different synthetic compounds, and different insecticide resistance mechanisms have been reported worldwide. METHODOLOGY/PRINCIPAL FINDINGS: To further characterize this resistance, we analyzed genome-wide transcriptional responses in three genotypes of M. persicae, each exhibiting different resistance mechanisms, in response to an anti-cholinesterase insecticide. The sensitive genotype (exhibiting no resistance mechanism) responded to the insecticide by up-regulating 183 genes primarily ones related to energy metabolism, detoxifying enzymes, proteins of extracellular transport, peptidases and cuticular proteins. The second genotype (resistant through a kdr sodium channel mutation), up-regulated 17 genes coding for detoxifying enzymes, peptidase and cuticular proteins. Finally, a multiply resistant genotype (carrying kdr and a modified acetylcholinesterase), up-regulated only 7 genes, appears not to require induced insecticide detoxification, and instead down-regulated many genes. CONCLUSIONS/SIGNIFICANCE: This study suggests strongly that insecticide resistance in M. persicae is more complex that has been described, with the participation of a broad array of resistance mechanisms. The sensitive genotype exhibited the highest transcriptional plasticity, accounting for the wide range of potential adaptations to insecticides that this species can evolve. In contrast, the multiply resistant genotype exhibited a low transcriptional plasticity, even for the expression of genes encoding enzymes involved in insecticide detoxification. Our results emphasize the value of microarray studies to search for regulated genes in insects, but also highlights the many ways those different genotypes can assemble resistant phenotypes depending on the environmental pressure
Influence of human biology and health (hbh) teachingâlearning process on studentsâ conceptions of the covid-19 vaccine
The COVIDâ19 pandemic created the need for universal vaccination. This study aimed to
compare university studentsâ (preâservice teachers) conceptions who had already learned the imâ
mune system and vaccination topics in the âHuman Biology and Health (HBH)â curricular unit with
those who had not yet taken part in it. It also intended to verify the influence of secondary school
background, perception of oneâs own health, feeling at risk for COVIDâ19 and their own experience
with it and scientific knowledge related to SARSâCoVâ2 vaccination. It was a crossâsectional study
with a mixed methodology for data analysis. A questionnaire was applied online to a sample of 102
university students. Results show that students who had already taken the subject on the immune
system and vaccination had more acceptable conceptions about the vaccine and wanted to be vacâ
cinated but not in the initial moment of the national vaccination process. The fear of adverse reacâ
tions seemed to be the major hesitancy factor. Furthermore, studentsâ argumentation showed that
their conceptions progressed towards more socioâscientific reasoning.info:eu-repo/semantics/publishedVersio
Enzymatic dyeing of wool
This study reports for the dyeing of wool using an enzymatic system comprising laccase (EC 1.10.3.2), dye precursor - 2,5-diaminobenzenesulfonic acid and dye modifiers â cathehol and resorcinol. The effect of the process variables - reaction time, enzyme and modifiers concentration on fabrics colour was studied, according to an appropriate experimental design. Different hues and depth of shades could be achieved varying the concentration of the modifiers and the time of laccase treatment. The duration of the enzymatic reaction appeared to be the most important factor in the dyeing process. Thus the dyeing process, performed at low temperature and mild pH, was advantageous in terms of reduced enzyme and chemicals dosage. The ability of the laccases to generate colour âin situâ from originally non-coloured, low-molecular substances, appears as an alternative to the conventional dyeing processes. The dye precursors can be used alone or in combination with suitable modifier (coupler) â another phenolic compound, which together with the dye precursor will enlarge the colour pallet achieved in the enzymatic dyeing
Enzymatic dyeing of keratinous materials
Poster apresentado no "Biotrans Olomouc 2003 - 6th International Symposium on Biocatalysis and Biotransformations", em Olomouc, Czech Republic, 2003This study reports on the dyeing of keratinous materials
using appropriate enzymatic systems â laccases and protein
disulfide isomerase. The enzymatic dyeing was performed as
a batchwise process at the temperature and pH of maximum
enzyme activity. Laccases generate the colour âin situâ starting
from low molecular colourless compounds â dye precursor
and dye modifiers. Different hues and depth of shades
could be achieved varying the concentration of the modifiers
and the time of laccase treatment. Protein disulfide isomerases,
based on their ability to catalyze thiol-disufide exchange,
including oxidation, reduction and rearrangement,
were used for covalent fixation of novel cysteine-modified
dyes on keratinous fibres
Alkali and acid polysaccharides blend nanofibrous membranes prepared by electrospinning
Poster apresentado no "Smart and functional coatings conference", Torino, Italy, 2013Electrospinning allows the production of polymer fibres with diameters in the sub-micron size range, through the application of an external electric field, keeping intact the bulk properties of the polymers. Electrospun membranes possess some unique structural features, such as a high surface to volume ratio and very good mechanical performance, properties that are determinant to their use in several applications such as air and liquid filtration, tissue engineering, optical and chemical sensors [1]. In this work, alkali and acid biopolysaccharides blended with polyvinyl alcohol (PVA) were electrospinned into a polyvinylidene difluoride (PVDF) basal microfiltration membrane, with the goal of developing a mid-layer nanofibrous porous support for exploitable thin-film composite (TFC) membranes for water filtration. The alkali and acid biopolysaccharides chosen were, respectively, chitosan (CS), a cationic polyelectrolyte (in this case with deacetylation degree around 85), and cyanobacterial extracellular polymeric substances (EPS), an acidic polysaccharide isolated from Cyanothece sp.CCY 0110 [2]. The electrospun blended nanofibrous membranes were fully characterized in order to investigate their morphology, diameter, structure, mechanical and thermal properties. The results showed that these membranes have great potential for filtration purposes [3].This work was funded by FEDER funds through the Operational Competitiveness Programme â COMPETE and by National Funds through FCT â Fundação para a CiĂȘncia e a Tecnologia under the projects FCOMP-01-0124-FEDER-022718 (PEst-C/SAU/LA0002/2011), FCOMP-01-0124-FEDER-009389 (PTDC/CTM/100627/2008) and FCOMP-01-0124-FEDER-009697 (PTDC/EBB-EBI/099662/2008), and the grants SFRH/BPD/37045/2007 and SFRH/BPD/72400/2010. The authors also thank to the project INVISIBLE NETWORK nÂș. 13857 * SI I&DT Mobilizador
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