736 research outputs found
Spin-orbit coupling and intrinsic spin mixing in quantum dots
Spin-orbit coupling effects are studied in quantum dots in InSb, a narrow-gap
material. Competition between different Rashba and Dresselhaus terms is shown
to produce wholesale changes in the spectrum. The large (and negative)
-factor and the Rashba field produce states where spin is no longer a good
quantum number and intrinsic flips occur at moderate magnetic fields. For dots
with two electrons, a singlet-triplet mixing occurs in the ground state, with
observable signatures in intraband FIR absorption, and possible importance in
quantum computation.Comment: REVTEX4 text with 3 figures (high resolution figs available by
request). Submitted to PR
Motivación al deporte en adultos y personas mayores que practican cachibol
Con el propósito de comprender la motivación en un grupo de adultos y personas mayores practican cachibol y los factores para continuar o desertar en la práctica de este deporte, se realizó un estudio con diseño descriptivo, transversal y exploratorio. Para tal n, se diseñó un instrumen- to denominado Escala de Motivación en el Deporte para Personas Mayores (EMDPM), fundamentado teóricamente para medir los motivos de inicio, continuidad y desmotivación, inicialmente en la práctica deportiva de per- sonas mayores. Se encontró que la motivación más importante se centra en la salud y entre los factores de desmotivación destacan los relacionados con la enfermedad y las lesiones.
Changes in Atlantic salmon (Salmo salar) sperm morphology and membrane lipid composition related to cold storage and cryopreservation
The cold storage and cryopreservation of semen decrease sperm quality. Morphological and biochemical analyses of spermatozoa provide valuable information for the optimization of storage protocols to obtain a sufficient number of spermatozoa for in vitro fertilization. The aim of this study was to evaluate the morphology and lipid composition of Atlantic salmon (Salmo salar) spermatozoa after storage at 4 °C and cryopreservation. Semen samples were obtained by stripping. One aliquot was stored at 4 °C for 7 days, and another aliquot was cryopreserved. The morphology and ultrastructure were analysed using electron microscopy. The lipid composition was analysed by gas chromatography and a commercial kit. After cold storage, the mitochondrion was the most affected component; however, plasma membrane rupture and detachment of the flagellum were also observed. Morphological abnormalities were greater in cryopreserved spermatozoa. The head and mid-piece were dehydrated, sperm membranes were vesiculated, and alterations of mitochondria were observed. After cold storage and cryopreservation, there were less polyunsaturated and omega-3 fatty acids. Furthermore, there was an increase in saturated fatty acids and decrease in cholesterol concentration after cryopreservation (P < 0.05). Based on the results, cryopreservation drastically damaged sperm membranes; the cryogenic damage was associated with membrane lipid composition alterations. The sperm membranes were affected less by cold storage but there was also a decrease of some lipids; therefore, there is a need for improvement in cold storage processes to decrease structural damage of spermatozoa so that semen cryopreservation can be effectively used in the salmon industr
Optimizing CIGB-300 intralesional delivery in locally advanced cervical cancer
Background:We conducted a phase 1 trial in patients with locally advanced cervical cancer by injecting 0.5 ml of the CK2-antagonist CIGB-300 in two different sites on tumours to assess tumour uptake, safety, pharmacodynamic activity and identify the recommended dose.Methods:Fourteen patients were treated with intralesional injections containing 35 or 70 mg of CIGB-300 in three alternate cycles of three consecutive days each before standard chemoradiotherapy. Tumour uptake was determined using 99 Tc-radiolabelled peptide. In situ B23/nucleophosmin was determined by immunohistochemistry.Results:Maximum tumour uptake for CIGB-300 70-mg dose was significantly higher than the one observed for 35 mg: 16.1±8.9 vs 31.3±12.9 mg (P=0.01). Both, AUC 24h and biological half-life were also significantly higher using 70 mg of CIGB-300 (P<0.001). Unincorporated CIGB-300 diffused rapidly to blood and was mainly distributed towards kidneys, and marginally in liver, lungs, heart and spleen. There was no DLT and moderate allergic-like reactions were the most common systemic side effect with strong correlation between unincorporated CIGB-300 and histamine levels in blood. CIGB-300, 70 mg, downregulated B23/nucleophosmin (P=0.03) in tumour specimens.Conclusion:Intralesional injections of 70 mg CIGB-300 in two sites (0.5 ml per injection) and this treatment plan are recommended to be evaluated in phase 2 studies.Fil: Sarduy, M. R.. Medical-surgical Research Center; CubaFil: García, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Coca, M. A.. Clinical Investigation Center; CubaFil: Perera, A.. Clinical Investigation Center; CubaFil: Torres, L. A.. Clinical Investigation Center; CubaFil: Valenzuela, C. M.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Baladrón, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Solares, M.. Hospital Materno Ramón González Coro; CubaFil: Reyes, V.. Center For Genetic Engineering And Biotechnology Havana; CubaFil: Hernández, I.. Isotope Center; CubaFil: Perera, Y.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Martínez, Y. M.. Medical-surgical Research Center; CubaFil: Molina, L.. Medical-surgical Research Center; CubaFil: González, Y. M.. Medical-surgical Research Center; CubaFil: Ancízar, J. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Prats, A.. Clinical Investigation Center; CubaFil: González, L.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Casacó, C. A.. Clinical Investigation Center; CubaFil: Acevedo, B. E.. Centro de Ingeniería Genética y Biotecnología; CubaFil: López Saura, P. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; ArgentinaFil: Gómez, R.. Elea Laboratories; ArgentinaFil: Perea Rodríguez, S. E.. Center For Genetic Engineering And Biotechnology Havana; Cuba. Centro de Ingeniería Genética y Biotecnología; Cub
Conflict transformation in indigenous' peoples territories: doing environmental justice with a 'decolonial turn'
One of the distinctive features of environmental justice theory in Latin America is its influence by decolonial thought, which explains social and environmental injustices as arising from the project of modernity and the ongoing expansion of a European cultural imaginary. The decolonization of knowledge and social relations is highlighted as one of the key challenges for overcoming the history of violent oppression and marginalization in development and conservation practice in the region. In this paper we discuss how conflict transformation theory and practice has a role to play in this process. In doing so, we draw on the Socio-environmental Conflict Transformation (SCT) framework elaborated by Grupo Confluencias, which puts a focus on building community capacity to impact different spheres of power: people and networks, structures and cultural power. We discuss this framework and its practical use in the light of ongoing experiences with indigenous peoples in Latin America. We propose that by strengthening the power of agency of indigenous peoples to impact each of these spheres it is possible to build constructive intra and intercultural relations that can help increase social and environmental justice in their territories and thus contribute to decolonizing structures, relations and ways of being
Effects of cryopreservation on cAMP-dependent protein kinase and AMP-activated protein kinase in Atlantic salmon (Salmo salar) spermatozoa: Relation with post-thaw motility
Sperm motility in fish with external fertilization is critical for reproductive efficiency in aquaculture, especially in salmonids. Gamete preservation techniques, such as cryopreservation, however, reduce sperm motility and fertilizing capacity. Very few studies have addressed cryodamage from energetic and cell signalling approaches. In this study, cAMP-dependent protein kinase (PKA) and AMP-activated kinase (AMPK) activities were quantified in fresh and cryopreserved spermatozoa of Atlantic salmon (Salmo salar); and the relation with motility was analysed. Results indicate there was a decrease in membrane integrity and motility in post-thawed spermatozoa compared to fresh samples, however, there was about 30% of cells with intact plasma membrane but incapable of motility. The PKA and AMPK activities were less after cryopreservation, indicating that loss of motility may be related to alteration of these key enzymes. Furthermore, PKA and AMPK activities were positively correlated with each other and with motility; and inhibition decreased motility, indicating there is a functional relationship between PKA and AMPK. The PKA inhibition also decreased AMPK activity, but results from protein-protein docking analyses indicated AMPK activation directly by PKA is unlikely, thus an indirect mechanism may exist. There have been no previous reports of these kinase actions in fish spermatozoa, making these findings worthy of assessment when there are future studies being planned, and may serve as base knowledge for optimization of cryopreservation procedures and development of biotechnologies to improve reproduction efficiency in the aquaculture industr
Novel single nucleotide polymorphisms in candidate genes for growth in tilapia ( Oreochromis niloticus )
Injection Drug Use as a Mediator Between Client-perpetrated Abuse and HIV Status Among Female Sex Workers in Two Mexico-US Border Cities
We examined relationships between client-perpetrated emotional, physical, and sexual abuse, injection drug use, and HIV-serostatus among 924 female sex workers (FSWs) in Tijuana and Ciudad Juarez, two large Mexico-US border cities. We hypothesized that FSWs’ injection drug use would mediate the relationship between client-perpetrated abuse and HIV-seropositivity. The prevalence of client-perpetrated emotional, physical, and sexual abuse in the past 6 months was 26, 18, and 10% respectively; prevalence of current injection drug use and HIV was 12 and 6%, respectively. Logistic regression analyses revealed that client-perpetrated sexual abuse was significantly associated with HIV-seropositivity and injection drug use, and that injection drug use was positively associated with HIV-seropositivity. Injection drug use partially mediated the relationship between client-perpetrated sexual abuse and HIV-seropositivity. Results suggest the need to address client-perpetrated violence and injection drug use when assessing HIV risk among FSWs
The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia
Adjuvant interferon gamma in patients with pulmonary atypical Mycobacteriosis: A randomized, double-blind, placebo-controlled study
<p>Abstract</p> <p>Background</p> <p>High antibiotic resistance is described in atypical Mycobacteriosis, mainly by <it>Mycobacterium avium </it>complex (MAC).</p> <p>Methods</p> <p>A randomized, double-blind, placebo-controlled clinical trial was carried out in two hospitals to evaluate the effect of interferon (IFN) gamma as immunoadjuvant to chemotherapy on patients with atypical mycobacteria lung disease. Patients received placebo or 1 × 10<sup>6 </sup>IU recombinant human IFN gamma intramuscularly, daily for one month and then three times per week up to 6 months as adjuvant to daily oral azithromycin, ciprofloxacin, ethambutol and rifampin. Sputum samples collection for direct smear observation and culture as well as clinical and thorax radiography assessments were done during treatment and one year after. Cytokines and oxidative stress determinations were carried out in peripheral blood before and after treatment.</p> <p>Results</p> <p>Eighteen patients were included in the IFN group and 14 received placebo. Groups were homogeneous at entry; average age was 60 years, 75% men, 84% white; MAC infection prevailed (94%). At the end of treatment, 72% of patients treated with IFN gamma were evaluated as complete responders, but only 36% in the placebo group. The difference was maintained during follow-up. A more rapid complete response was obtained in the IFN group (5 months before), with a significantly earlier improvement in respiratory symptoms and pulmonary lesions reduction. Disease-related deaths were 35.7% of the patients in the placebo group and only 11.1% in the IFN group. Three patients in the IFN group normalized their globular sedimentation rate values. Although differences in bacteriology were not significant during the treatment period, some patients in the placebo group converted again to positive during follow-up. Significant increments in serum TGF-beta and advanced oxidation protein products were observed in the placebo group but not among IFN receiving patients. Treatments were well tolerated. Flu-like symptoms predominated in the IFN gamma group. No severe events were recorded.</p> <p>Conclusion</p> <p>These data suggest that IFN gamma is useful and well tolerated as adjuvant therapy in patients with pulmonary atypical Mycobacteriosis, predominantly MAC. Further wider clinical trials are encouraged.</p> <p>Trial registration</p> <p>Current Controlled Trials ISRCTN70900209.</p
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