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1.
Ginecol Obstet Mex ; 83(7): 422-8, 2015 Jul.
Artigo em Espanhol | MEDLINE | ID: mdl-26422913

RESUMO

OBJECTIVES: To evaluate the effectiveness of the hysteroscopic polypectomy in terms of the decrease of the abnormal uterine bleeding. METHODS: A cross-sectional and analytical study was done with patients to whom a hysteroscopic polypectomy was done for treating the abnormal uterine bleeding, between January 2009 and December 2013. The response to the treatment was evaluated via a survey given to the patients about the behavior of the abnormal uterine bleeding after the procedure and about overall satisfaction. RESULTS: The results were obtained after a hysteroscopic polypectomy done to 128 patients and were as follows. The average time from the polypectomy applied until the survey was 30.5 months, with a standard deviation of 18 months. 67.2% of the patients reported decreased abnormal uterine bleeding and the 32.8% reported a persistence of symptoms. On average 82.8% of the. patients were satisfied with the treatment. Bivariate and multivariate analysis showed no association between the variables studied and no improvement of abnormal uterine bleeding after surgery (polypectomy). There were no complications. CONCLUSION: Hysteroscopic polypectomy is a safe surgical treatment, which decreases on two of three patients the abnormal uterine bleeding in the presence of endometrial polyps, with an acceptable level of satisfaction.


Assuntos
Histeroscopia/métodos , Pólipos/cirurgia , Doenças Uterinas/cirurgia , Hemorragia Uterina/cirurgia , Adulto , Estudos Transversais , Coleta de Dados , Feminino , Humanos , Pessoa de Meia-Idade , Análise Multivariada , Satisfação do Paciente , Pólipos/complicações , Fatores de Tempo , Resultado do Tratamento , Doenças Uterinas/patologia , Hemorragia Uterina/patologia
2.
Reumatol Clin ; 2023 Apr 04.
Artigo em Espanhol | MEDLINE | ID: mdl-37361904

RESUMO

Recent evidence shows that COVID-19 infection does not have a worse prognosis in patients with immune-mediated inflammatory diseases (IMID), although they develop a worse response to vaccination.Objective To compare the incidence of COVID-19 and clinical features in patients with IMID between the first and sixth waves.Method Prospective observational study of two cohorts of IMID patients diagnosed with COVID-19. First cohort March to May 2020, and second cohort December/2021 to February/2022.Sociodemographic and clinical variables were collected and, in the second cohort, COVID-19 vaccination status. Statistical analysis established differences in characteristics and clinical course between the two cohorts.Results In total, 1627 patients were followed up, of whom 77 (4.60%) contracted COVID-19 during the first wave and 184 in the sixth wave (11.3%). In the sixth wave, there were fewer hospitalisations, intensive care unit admissions, and deaths than in the first wave (p=.000) and 180 patients (97.8%) had at least one dose of vaccine.Conclusion Early detection and vaccination have prevented the occurrence of serious complications.

3.
Phys Rev Lett ; 105(12): 120601, 2010 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-20867619

RESUMO

Diffusion-limited reactions are usually described within the Smoluchowski theory, which neglects interparticle interactions. We propose a simple way to incorporate excluded-volume effects building on simulations of hard sphere in the presence of a sink. For large values of the sink-to-particle size ratio R(s), the measured encounter rate is in good agreement with a simple generalization of the Smoluchowski equation at high densities. Reducing R(s), the encounter rate is substantially depressed and becomes even nonmonotonic for R(s)<<1. Concurrently with the saturation of the rate, stationary density waves set in close to the sink. A mean-field analysis helps to shed light on the subtle link between such ordering and the slowing down of the encounter dynamics. Finally, we show how an infinitesimal amount of nonreacting impurities can equally slow down dramatically the reaction.


Assuntos
Simulação de Dinâmica Molecular , Nanopartículas/química , Polímeros/química , Algoritmos , Coloides/química , Difusão , Tamanho da Partícula
4.
Eur Phys J E Soft Matter ; 33(1): 89-96, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20852913

RESUMO

In this paper we analyze the vibrational spectra of a large ensemble of non-homologous protein structures by means of a novel tool, that we coin Hierarchical Network Model (HNM). Our coarse-grained scheme accounts for the intrinsic heterogeneity of force constants displayed by protein arrangements and also incorporates side chain degrees of freedom. Our analysis shows that vibrational entropy per unit residue correlates with the content of secondary structure. Furthermore, we assess the individual contribution to vibrational entropy of the novel features of our scheme as compared with the predictions of state-of-the-art network models. This analysis highlights the importance of properly accounting for the intrinsic hierarchy in force strengths typical of the different atomic bonds that build up and stabilize protein scaffolds. Finally, we discuss possible implications of our findings in the context of protein aggregation phenomena.


Assuntos
Entropia , Proteínas/química , Vibração , Bases de Dados de Proteínas , Modelos Moleculares , Estabilidade Proteica , Estrutura Secundária de Proteína , Análise Espectral
5.
J Obstet Gynaecol ; 30(1): 49-52, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20121505

RESUMO

We prospectively collected data on all patients with stage IB1 cervical cancer, who underwent total laparoscopic radical hysterectomy with the use of a modified uterine manipulator. From January 2000 to December 2005, 54 patients met the study criteria. The mean age was 41.8 +/- 7.47 years. Average BMI (kg/m(2)) was 27.38 +/- 3.13. Squamous carcinoma and adenocarcinoma were found in 88.88% and 11.11% of the cases, respectively. The average surgical time was 265 +/- 70.8 min. The mean estimated blood loss was 276.11 +/- 123.03 ml. The average patient lymph node count was 19.64 +/- 5.08. Positive malignant lymph nodes were identified in 11.11% of the cases. Surgical margins were free of disease in all patients. The mean hospital stay was 1.5 +/- 1 days. There was no mortality. Total laparoscopic radical hysterectomy can be considered a safe alternative to laparotomy. The use of a uterine manipulator does not pose an increased surgical risk and allows for a simpler and more feasible procedure.


Assuntos
Adenocarcinoma/cirurgia , Carcinoma de Células Escamosas/cirurgia , Histerectomia Vaginal/instrumentação , Laparoscopia/métodos , Neoplasias do Colo do Útero/cirurgia , Adulto , Feminino , Humanos , Histerectomia Vaginal/métodos , Pessoa de Meia-Idade , Estudos Prospectivos
6.
Braz J Biol ; 80(2): 362-367, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31389484

RESUMO

The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.


Assuntos
Gastrópodes , Invertebrados , Animais , Organismos Aquáticos , Chile , Ecossistema
7.
Braz J Biol ; 80(4): 735-740, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31800760

RESUMO

The management and use of native species under laboratory conditions is the main difficult for species proposal for its use in bioassays. The present study showed the results about management under controlled conditions of Paratanytarsus grimmii (Diptera: Chironomidae), that is a parthenogenetic species with wide geographical distribution. It obtained its eggs from a pre Andean river from Araucania region (39° S), and it determined the conditions for larval rearing under artificial food, adults getting (manipulation), eggs (hatching sincronization) and larvae getting after hatching. The P.grimmii life cycle had larvae that late 23 days in get the pupa stage (stage I to IV), the adult within the next 48 hours deposits the eggs that hatched at 72 hours. It stablished laboratory conditions: incubation room temperature, water pH, and artificial feeding, photoperiod and larvae and eggs management techniques. In according to obtained results it managed all life cycles under laboratory conditions that can propose the use of this species as potential biological material for toxicity bioassays.


Assuntos
Chironomidae , Dípteros , Animais , Bioensaio , Larva , Pupa , Padrões de Referência
8.
Braz J Biol ; 80(4): 907-913, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31800771

RESUMO

Studies in Salvelinus alpinus, Arctic charr, indicate that it has a low capacity to hyposmorregulatory or adaption to sea in winter periods in Arctic waters. The investigation finds to determinate the rank optimum of salinity to can cultivate this species at Chile. The weight adequate was determined to join on the sea by analysis of gill Na+, K+-ATPase activity, that it was found between the ranks 80-130 g, with 14.5 U/mg. It underwent evaluation of fish growth of 72 g salinities from 0 (control), 18, 25 and 33 g/L (sea water) for 94 days. The results indicate that the largest increases were obtained in brackish water. T18 g/L and T25 g/L achieved growth of 25% and 19% on day 94 and term sampling respectively. It is important to mention that the 8% that survived in seawater introduced percentages growth 16.6% equivalent to brackish water and control. These results suggest that Salvelinus alpinus can grow in seawater, with levels of Na+, K+-ATPase similar to those submitted by Salmo salar with a weight not less than 80 g.


Assuntos
Salinidade , ATPase Trocadora de Sódio-Potássio , Animais , Chile , Brânquias , ATPase Trocadora de Sódio-Potássio/metabolismo , Truta/metabolismo
9.
Braz J Biol ; 79(4): 646-650, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30427382

RESUMO

Deionized ammonium (NH3) acute toxicity (LC50-96h) in Patagonian blenny juveniles (Eleginops maclovinus) was assessed. Concentrations of deionized ammonium in salt water were prepared by using 24.09 ± 2.1 g ammonium chloride (NH4Cl). Fish were exposed in triplicates to different ammonium concentrations: 0.05; 0.094; 0.175; 0.325 and 0.605 mg NH3 L-1. Additionally, a control group was included. Experimental fish were kept at a photoperiod of 16:8h. Average temperatures were 16.24 ± 1.40 °C. Oxygen concentration was 7.16 ± 0.40 mg L -1. Water pH was 7.89 ± 0.2. LC50-96 h, was estimated by using Probit statistical method (95% intervals) using EPA software (1993). Juveniles of E. maclovinus showed a LC50-96h of 0.413mg NH3 L-1 value, different from most marine species. This study presents the first record of ammonium toxicity in marine species of Chile.


Assuntos
Compostos de Amônio/toxicidade , Doenças dos Peixes/induzido quimicamente , Perciformes , Animais , Chile , Perciformes/crescimento & desenvolvimento , Perciformes/fisiologia , Temperatura , Poluentes Químicos da Água/toxicidade
10.
Rev Neurol ; 69(3): 94-98, 2019 Aug 01.
Artigo em Espanhol, Inglês | MEDLINE | ID: mdl-31309998

RESUMO

INTRODUCTION: Chemotherapy-induced peripheral neuropathy is a common adverse reaction in a variety of medications frequently used for a great number of cancer treatments. This condition consists of mainly sensory-type symptoms, motor components and autonomic changes. Reported prevalence ranges from 30-68%, after the completion of chemotherapy in non-Latin American people with different populations and socioeconomic levels. AIM: To determine the prevalence of chemotherapy-induced peripheral neuropathy in a Colombian population. PATIENTS AND METHODS: A real-world evidence cross-sectional retrospective study was performed in all patients from oncological clinical centers in Colombia, which received pharmacological therapy for any cancer between January 2015 and December 2016, with taxanes (paclitaxel, docetaxel), alkylators (oxaliplatin), proteasome inhibitors (bortezomib), and epothilone B analogs (ixabepilone). RESULTS: A total of 1,551 patients in four cities were included, and 11,280 doses were applied; predominantly females (n = 1,094; 70.5%), with a mean age of 57 ± 13 years old. Paclitaxel was the most commonly prescribed drug (n = 788; 50.8%). Chemotherapy-induced peripheral neuropathy was developed in 48.9% of paclitaxel, 58.5% of oxaliplatin, 50.5% of docetaxel, 43.7% of bortezomib and 95.2% of ixabepilone patients. Thirty-three patients were treated with two of these medications simultaneously. CONCLUSIONS: Chemotherapy-induced peripheral neuropathy is a frequent adverse reaction to daily cancer therapy in Colombian patients managed with taxanes, alkylators, proteasome inhibitors, and epothilone B analogs. Hence, it is necessary to establish more successful diagnostic methods and incorporate validated scales in the routine evaluation of all patients receiving these medications in our environment.


TITLE: Prevalencia de neuropatia periferica asociada a quimioterapia en cuatro centros oncologicos de Colombia.Introduccion. La neuropatia periferica inducida por quimioterapia es una reaccion comun a una variedad de medicamentos usados en el tratamiento del cancer, que consiste principalmente en sintomas sensitivos, con componentes motores y cambios autonomicos. La prevalencia es del 30-68% despues de terminar la quimioterapia en paises no latinoamericanos. Objetivo. Determinar la prevalencia de la neuropatia periferica inducida por quimioterapia en la poblacion colombiana. Pacientes y metodos. Estudio retrospectivo con evidencia del mundo real en la totalidad de pacientes atendidos en cuatro centros oncologicos de Colombia, quienes recibieron terapia farmacologica para algun tipo de cancer entre enero de 2015 y diciembre de 2016 con taxanos (paclitaxel, docetaxel), agentes alquilantes (oxaliplatino), inhibidores de proteasoma (bortezomib) y analogos de epotilona B (ixabepilona). Resultados. Se siguio a un total de 1.551 pacientes en cuatro ciudades a quienes se les aplicaron 11.280 dosis, con predominio femenino (n = 1.094; 70,5%) y una edad media de 57 ± 13 años. El paclitaxel fue el farmaco mas prescrito (n = 788; 50,8%). La neuropatia inducida por quimioterapia se presento en el 48,9% de los pacientes con paclitaxel, el 58,5% de los pacientes con oxaliplatino, el 50,5% de los pacientes con docetaxel, el 43,7% de los pacientes con bortezomib y el 95,2% de los pacientes con ixabepilona. Se trato a 33 pacientes con dos de estos medicamentos simultaneamente. Conclusiones. La neuropatia periferica inducida por quimioterapia es una reaccion adversa frecuente en pacientes con cancer en Colombia tratados con taxanos, alquilantes, inhibidores de proteasoma e ixabepilona. Es necesario establecer metodos diagnosticos efectivos e incorporar escalas validadas en la evaluacion rutinaria de los pacientes que reciben estas medicaciones.


Assuntos
Antineoplásicos/efeitos adversos , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Adulto , Idoso , Antineoplásicos/uso terapêutico , Bortezomib/efeitos adversos , Institutos de Câncer/estatística & dados numéricos , Colômbia/epidemiologia , Estudos Transversais , Epotilonas/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oxaliplatina/efeitos adversos , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/epidemiologia , Prevalência , Inibidores de Proteases/efeitos adversos , Estudos Retrospectivos , Taxoides/efeitos adversos
11.
Cancer Res ; 59(15): 3658-62, 1999 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-10446978

RESUMO

A case-control study was carried out in Mexico City during 1995-1997 among women with epithelial ovarian cancer (84 cases) and endometrial cancer (85 cases). The control group consisted of 668 healthy women, matched according to age categories. In a multivariate analysis, the reproductive risk factors for ovarian and endometrial cancer are similar. The risk of ovarian cancer was inversely related to the number of full-term pregnancies; the odds ratio (OR) was 0.17 and the 95% confidence interval (CI) was 0.05-0.54 when comparing nulliparous women versus those with more than seven pregnancies. For endometrial cancer, a similar association was observed (OR, 0.11; 95% CI, 0.04-0.34). The use of oral contraceptive hormones was inversely associated with both ovarian (OR, 0.36; 95% CI, 0.15-0.83) and endometrial cancer risk (OR, 0.36; 95% CI, 0.14-0.90). In women with a history of more than 8.7 years without ovulation, the risk of ovarian cancer decreased four times (OR, 0.23; 95% CI, 0.10-0.50), and that of endometrial cancer decreased more than five times (OR, 0.17; 95% CI, 0.08-0.35). These two neoplasms are clearly typified as hormone dependent, and it is possible to establish that "ovulation" and "exfoliative" mechanisms jointly determine the level of risk for both ovarian and endometrial cancer.


Assuntos
Neoplasias do Endométrio/epidemiologia , Estrogênios , Neoplasias Hormônio-Dependentes/epidemiologia , Neoplasias Ovarianas/epidemiologia , Paridade , Progesterona , História Reprodutiva , Aleitamento Materno/estatística & dados numéricos , Estudos de Casos e Controles , Anticoncepcionais Orais Hormonais , Feminino , Terapia de Reposição Hormonal , Humanos , Dispositivos Intrauterinos , Menarca , Menopausa , México/epidemiologia , Pessoa de Meia-Idade , Modelos Biológicos , Ovulação , Fatores de Risco
13.
Biophys Chem ; 115(2-3): 235-40, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15752611

RESUMO

The issue of protein dynamics and its implications in the biological function of proteins are arousing greater and greater interest in molecular biology. In cryo-electron tomography experiments one takes several snapshots of a given biological macromolecule. In principle, a large enough collection of snapshots may then be used to calculate its equilibrium configuration in terms of the experimentally accessible degrees of freedom, and hence estimate its potential energy. Consequently, one could analyze the biological functions of biomolecules by directly accessing their dynamics. In this work, we analyze the results of cryo-electron tomography experiments on monoclonal murine IgG2a antibodies. With the aid of a novel software for image processing, we measure the equilibrium distribution of the angles which describe the configuration of the molecule. This helps us shed some critical light on recent results from X-ray crystallography. We then build a model of the antibody dynamics, which enables us to use the measured angular distribution in order to derive an explicit expression of the IgG potential energy. Finally, as a preliminary application of our results, we investigate the dynamical effects in the rate of formation of the antigen-antibody encounter complex. In particular, we suggest that the dynamics of antibodies operates in the direction of decreasing anticooperativity of the two antigen binding arms.


Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Tomografia/métodos , Animais , Antígenos/química , Antígenos/imunologia , Elétrons , Camundongos , Conformação Proteica
14.
Braz. j. biol ; 80(2): 362-367, Apr.-June 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1132389

RESUMO

Abstract The rocky shores in Chile have a wide invertebrate species diversity, that include species with marked abundances in determined regions. The aim of the present study is to analyse the spatial distribution pattern in different marine invertebrate species in rocky shore of Araucania region, considering if these species have random, uniform or associated patterns, and extrapolate if these patterns have Poisson, binomial or negative binomial distribution respectively. The results revealed the presence mainly of gastropods molluscs that would graze on benthic algae, these species have mainly aggregated pattern that has a robust negative binomial distribution pattern. The obtained results agree with observations for marine benthic fauna that mentioned the presence of aggregated pattern, has negative binomial distribution. Other ecological topics about spatial distribution were discussed.


Resumo As costas rochosas no Chile têm uma ampla diversidade de espécies de invertebrados, que incluem espécies com abundância marcada em determinadas regiões. O objetivo do presente estudo é analisar o padrão de distribuição espacial em diferentes espécies de invertebrados marinhos na costa rochosa da região de Araucanía, considerando se essas espécies possuem padrões aleatórios, uniformes ou associados, e extrapolar se esses padrões possuem distribuição binomial de Poisson, binomial ou negativa. respectivamente. Os resultados revelaram a presença principalmente de moluscos gastrópodes que pastam em algas bentônicas, estas espécies têm principalmente agregado padrão que tem um padrão robusto de distribuição binomial negativa, padrão agregado de grupos, e a fauna de água doce que apresenta distribuição binomial negativa. Outros tópicos ecológicos sobre distribuição espacial foram discutidos.


Assuntos
Animais , Gastrópodes , Invertebrados , Chile , Ecossistema , Organismos Aquáticos
15.
Braz. j. biol ; 80(4): 735-740, Oct.-Dec. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1142518

RESUMO

Abstract The management and use of native species under laboratory conditions is the main difficult for species proposal for its use in bioassays. The present study showed the results about management under controlled conditions of Paratanytarsus grimmii (Diptera: Chironomidae), that is a parthenogenetic species with wide geographical distribution. It obtained its eggs from a pre Andean river from Araucania region (39° S), and it determined the conditions for larval rearing under artificial food, adults getting (manipulation), eggs (hatching sincronization) and larvae getting after hatching. The P.grimmii life cycle had larvae that late 23 days in get the pupa stage (stage I to IV), the adult within the next 48 hours deposits the eggs that hatched at 72 hours. It stablished laboratory conditions: incubation room temperature, water pH, and artificial feeding, photoperiod and larvae and eggs management techniques. In according to obtained results it managed all life cycles under laboratory conditions that can propose the use of this species as potential biological material for toxicity bioassays.


Resumo O manejo e o uso de espécies nativas em condições de laboratório são as principais dificuldades para a proposta de uso de espécies em bioensaios. O presente estudo mostrou os resultados acerca do manejo sob condições controladas de Paratanytarsus grimmii (Diptera: Chironomidae), espécie partenogenética com ampla distribuição geográfica. Foram obtidos seus ovos de um rio pré-andino da região de Araucanía (39º S) e determinadas as condições para criação de larvas sob alimentação artificial, obtenção de adultos (manipulação), de ovos (sincronização de eclosão) e de larvas após a eclosão. O ciclo de vida de P. grimmii teve larvas que, ao final dos 23 dias, atingiram o estágio de pupa (estágio I a IV). O adulto depositou nas 48 horas seguintes os ovos que eclodiram às 72 horas. Foram estabelecidas condições laboratoriais: temperatura da sala de incubação, pH da água e alimentação artificial, fotoperíodo e técnicas de manejo de larvas e ovos. De acordo com os resultados obtidos, foram gerenciados todos os ciclos de vida em condições de laboratório que podem propor o uso dessa espécie como material biológico potencial para bioensaios de toxicidade.


Assuntos
Animais , Chironomidae , Dípteros , Pupa , Padrões de Referência , Bioensaio , Larva
16.
Braz. j. biol ; 80(4): 907-913, Oct.-Dec. 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1142535

RESUMO

Abstract Studies in Salvelinus alpinus, Arctic charr, indicate that it has a low capacity to hyposmorregulatory or adaption to sea in winter periods in Arctic waters. The investigation finds to determinate the rank optimum of salinity to can cultivate this species at Chile. The weight adequate was determined to join on the sea by analysis of gill Na+, K+-ATPase activity, that it was found between the ranks 80-130 g, with 14.5 U/mg. It underwent evaluation of fish growth of 72 g salinities from 0 (control), 18, 25 and 33 g/L (sea water) for 94 days. The results indicate that the largest increases were obtained in brackish water. T18 g/L and T25 g/L achieved growth of 25% and 19% on day 94 and term sampling respectively. It is important to mention that the 8% that survived in seawater introduced percentages growth 16.6% equivalent to brackish water and control. These results suggest that Salvelinus alpinus can grow in seawater, with levels of Na+, K+-ATPase similar to those submitted by Salmo salar with a weight not less than 80 g.


Resumo Estudos em Salvelinus alpinus, Charr Ártico, indicam que tem baixa capacidade de hiposmorregulação ou adaptação ao mar em períodos de inverno nas águas do Ártico. A investigação determina o melhor nível de salinidade para cultivar esta espécie no Chile. Determinou-se o peso adequado para se unir ao mar pela análise da atividade da Na +, K + -ATPase das brânquias, que foi encontrada entre as faixas de 80 a 130 g, com 14,5 U/mg. Foi avaliado o crescimento de 72 g salinidades de 0 (controle), 18, 25 e 33 g/L (água do mar) por 94 dias. Os resultados indicam que os maiores aumentos foram obtidos em água salobra. T18 g/L e T25 g/L alcançaram crescimento de 25% e 19% no dia 94 e amostragem a termo, respectivamente. É importante mencionar que os 8% que sobreviveram na água do mar apresentaram percentuais de crescimento de 16,6% equivalentes a água salobra e controle. Estes resultados sugerem que o Salvelinus alpinus pode crescer em água do mar, com níveis de Na +, K + -ATPase semelhantes aos apresentados por Salmo salar com um peso não inferior a 80 g.


Assuntos
Animais , ATPase Trocadora de Sódio-Potássio/metabolismo , Salinidade , Truta/metabolismo , Chile , Brânquias
17.
Phys Rev Lett ; 85(23): 4848-51, 2000 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-11102133

RESUMO

We study the properties of the "rigid Laplacian" operator; that is we consider solutions of the Laplacian equation in the presence of fixed truncation errors. The dynamics of convergence to the correct analytical solution displays the presence of a metastable set of numerical solutions, whose presence can be related to granularity. We provide some scaling analysis in order to determine the value of the exponents characterizing the process. We believe that this prototype model is also suitable to provide an explanation of the widespread presence of power law in a social and economic system where information and decision diffuse, with errors and delay from agent to agent.

18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 63(3 Pt 1): 031802, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11308669

RESUMO

We introduce a polymer model where the transition from swollen to compact configurations is due to interactions between the monomers and the solvent. These interactions are the origin of the effective attractive interactions between hydrophobic amino acids in proteins. We find that in the low and high temperature phases polymers are swollen, and there is an intermediate phase where the most favorable configurations are compact. We argue that such a model captures in a single framework both the cold and the warm denaturation experimentally detected for thermosensitive polymers and for proteins.

19.
Phys Rev E Stat Nonlin Soft Matter Phys ; 66(6 Pt 1): 061911, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12513322

RESUMO

Protein design is important to develop new drugs. As such, a knowledge of the correct model to use to design novel proteins is of the utmost importance. Here we show that a simple model where the solvent degrees of freedom are (semi)explicitly taken into account performs better than other existing models when compared to real data. Some consequences on the criteria to be used for protein design are discussed.

20.
Phys Rev E Stat Nonlin Soft Matter Phys ; 69(6 Pt 1): 061924, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15244634

RESUMO

We investigate the aggregation of amphiphilic molecules by adapting the two-state Muller-Lee-Graziano model for water, in which a solvent-induced hydrophobic interaction is included implicitly. We study the formation of various types of micelle as a function of the distribution of hydrophobic regions at the molecular surface. Successive substitution of nonpolar surfaces by polar ones demonstrates the influence of hydrophobicity on the upper and lower critical solution temperatures. Aggregates of lipid molecules, described by a refinement of the model in which a hydrophobic tail of variable length interacts with different numbers of water molecules, are stabilized as the length of the tail increases. We demonstrate that the essential features of micelle formation are primarily solvent-induced, and are explained within a model which focuses only on the alteration of water structure in the vicinity of the hydrophobic surface regions of amphiphiles in solution.


Assuntos
Micelas , Modelos Químicos , Modelos Moleculares , Solventes/química , Água/química , Coloides/química , Simulação por Computador , Interações Hidrofóbicas e Hidrofílicas , Substâncias Macromoleculares , Conformação Molecular , Soluções
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