791 research outputs found
Different cell disruption methods for astaxanthin recovery by Phaffia rhodozyma
Astaxanthin (3,3'-dihydroxy-b,b'-carotene-4,4'-dione) is carotenoid of high market value whose demand has increased in such fields as aquaculture, pharmaceutical supplements and natural coloring. Cell disruption is the first step for isolating intracellular materials and it depends on the cell wall permeability. In order to maximize the recovery of astaxanthin from Phaffia rhodozyma NRRL-Y17268, drying and freeze pretreatments were tested by different cell disruption methods: abrasion with celite, glass pearls in vortex agitator, ultrasonic waves, sodium carbonate (Na2CO3) and dimethyl sulfoxide (DMSO). The method with Na2CO3 was not effective; meanwhile, the agitator with glass pearls, the abrasion with celite and the ultrasonic waves were found as promising for future studies. As a result, the DMSO in freeze-dried biomass with 4 process cycles and biomass/DMSO relation of 0.025 g/ml was found to be the most efficient for analytical determination, increasing about up to 25 times the astaxanthin recovery.Key words: Carotenoids, yeast, chemical disruption, dimethyl sulfoxide
Performance of a North American Field Population and a Laboratory Colony of the Potato Tuberworm, Phthorimaea operculella, on Foliage of Resistant and Susceptible Potato Clones
Foliar resistance of two potato clones was tested against a Columbia Basin field population (CBFP) and a Colorado laboratory colony (COLC) of the potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). The first clone was a cross of a cultivated potato, Solanum tuberosum L. (Solanales: Solanaceae), and a wild potato, Solanum berthaultii Hawkes (Q 174-2); the second clone was cv. Allegany, S. tuberosum L.. In no-choice assays, defoliation by P. operculella larvae of COLC and CBFP did not differ on Allegany and Q174-2. Larval weight and production of COLC and CBFP colonies were similarly reduced on Q174-2 compared to cv. Allegany, although larval weights and production of the CBFP population were slightly less affected by the host. Larval production by the COLC on Allegany was greater than that on Q174-2, while that of the CBFP on Allegany and Q174-2 did not differ. However, production of P. operculella larvae by the CBFP on Q174-2 during no-choice assays was greater than that in choice tests, indicating reduced host preference. Most of the larvae recovered from either host were fourth instars, followed by third instars. Although the levels of resistance expressed by Q174-2 potato clone to the two P. operculella populations differed in magnitude, nearly all of P. operculella performance criteria measured in this study were adversely affected by Q174-2 foliage compared to the commercial potato cultivar, cv. Allegany
Scoping review on vector-borne diseases in urban areas : transmission dynamics, vectorial capacity and co-infection
BACKGROUND: Transmission dynamics, vectorial capacity, and co-infections have substantial impacts on vector-borne diseases (VBDs) affecting urban and suburban populations. Reviewing key factors can provide insight into priority research areas and offer suggestions for potential interventions. MAIN BODY: Through a scoping review, we identify knowledge gaps on transmission dynamics, vectorial capacity, and co-infections regarding VBDs in urban areas. Peer-reviewed and grey literature published between 2000 and 2016 was searched. We screened abstracts and full texts to select studies. Using an extraction grid, we retrieved general data, results, lessons learned and recommendations, future research avenues, and practice implications. We classified studies by VBD and country/continent and identified relevant knowledge gaps. Of 773 articles selected for full-text screening, 50 were included in the review: 23 based on research in the Americas, 15 in Asia, 10 in Africa, and one each in Europe and Australia. The largest body of evidence concerning VBD epidemiology in urban areas concerned dengue and malaria. Other arboviruses covered included chikungunya and West Nile virus, other parasitic diseases such as leishmaniasis and trypanosomiasis, and bacterial rickettsiosis and plague. Most articles retrieved in our review combined transmission dynamics and vectorial capacity; only two combined transmission dynamics and co-infection. The review identified significant knowledge gaps on the role of asymptomatic individuals, the effects of co-infection and other host factors, and the impacts of climatic, environmental, and socioeconomic factors on VBD transmission in urban areas. Limitations included the trade-off from narrowing the search strategy (missing out on classical modelling studies), a lack of studies on co-infections, most studies being only descriptive, and few offering concrete public health recommendations. More research is needed on transmission risk in homes and workplaces, given increasingly dynamic and mobile populations. The lack of studies on co-infection hampers monitoring of infections transmitted by the same vector. CONCLUSIONS: Strengthening VBD surveillance and control, particularly in asymptomatic cases and mobile populations, as well as using early warning tools to predict increasing transmission, were key strategies identified for public health policy and practice
Adrenocortical oncocytic neoplasm presenting with Cushing's syndrome: a case report
<p>Abstract</p> <p>Introduction</p> <p>Oncocytic neoplasms occur in several organs and are most commonly found in the thyroid, kidneys and salivary glands. Oncocytic neoplasms of the adrenal cortex are extremely rare and are usually non-functioning.</p> <p>Case presentation</p> <p>We report the case of an adrenocortical oncocytic neoplasm with uncertain malignant potential in a 31-year-old man with Cushing's syndrome. The patient had been operated on following diagnosis of a 7 cm adrenal mass. Following surgery, the Cushing's syndrome resolved. The patient is still alive with no metastases one year after the surgery.</p> <p>Conclusion</p> <p>Adrenocortical oncocytic neoplasms must be considered in the differential diagnosis of both functioning and non-functioning adrenal masses.</p
Discrete family symmetry, Higgs mediators and theta_{13}
We present a new (supersymmetric) framework for obtaining an excellent
description of quark, charged lepton and neutrino masses and mixings from a
Delta(6n^2) family symmetry with multiplet assignments consistent with an
underlying SO(10) Grand Unification. It employs a Higgs mediator sector in
place of the usual Froggatt-Nielsen messengers, with quark and lepton
messengers, and provides significant improvements over existing models of this
type having unsuppressed Yukawa couplings to the third generation and a
simplified vacuum alignment mechanism. The neutrino mass differences are
naturally less hierarchical than those of the quarks and charged leptons.
Similarly the lepton mixing angles are much larger than those in the quark
sector and have an approximate tri-bi-maximal (TB) mixing form for theta_{12}
and theta_{23}. However the mixing angle theta_{13} is naturally much larger
than in pure TB mixing and can be consistent with the value found in recent
experiments. The magnitude of theta_{13} is correlated with a the predicted
deviation of theta_{23} from bi-maximal mixing. The model has light familon
fields that can significantly modify the associated SUSY phenomenology.Comment: v3: accepted in JHE
Generalised CP and Family Symmetry in Semi-Direct Models of Leptons
We perform a detailed analysis of family symmetry combined
with a generalised CP symmetry in the lepton sector, breaking to different
remnant symmetries in the neutrino and in the charged lepton
sector, together with different remnant CP symmetries in each sector. We
discuss the resulting mass and mixing predictions for with
and with . All cases correspond to
the preserved symmetry smaller than the full Klein symmetry, as in the
semi-direct approach, leading to predictions which depend on a single
undetermined real parameter, which mainly determines the reactor angle. We
focus on five phenomenologically allowed cases for which we present the
resulting predictions for the PMNS parameters as a function of , as well as
the predictions for neutrinoless double beta decay.Comment: 65 pages, 19 figures, and the predictions for neutrinoless double
beta decay are update
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