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1.
Sensors (Basel) ; 24(5)2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38474940

RESUMEN

The effects of the use of reduced feedback frequencies on motor learning remain controversial in the scientific literature. At present, there is still controversy about the guidance hypothesis, with some works supporting it and others contradicting it. To shed light on this topic, an experiment was conducted with four groups, each with different feedback frequencies (0%, 33%, 67%, and 100%), which were evaluated three times (pre-test, post-test, and retention) during a postural control task. In addition, we tested whether there was a transfer in performance to another similar task involving postural control. As a result, only the 67% feedback group showed an improvement in their task performance in the post-test and retention evaluations. Nevertheless, neither group showed differences in motor transfer performance compared to another postural control task. In conclusion, the findings of this paper corroborate the hypothesis of guidance and suggest that the use of a reduced frequency of 67% is a better option for improving motor learning than options that offer feedback at a lower frequency, at all trials or not at all.


Asunto(s)
Aprendizaje , Equilibrio Postural , Humanos , Adulto Joven , Retroalimentación , Análisis y Desempeño de Tareas , Análisis de Varianza , Destreza Motora
2.
Am Nat ; 201(1): 78-90, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36524927

RESUMEN

AbstractEmpirical evidence for the climate variability and performance trade-off hypotheses is limited to animals, and it is unclear whether climate constrains the photosynthetic strategies of plants. The plant genus Scalesia Arn. ex Lindl (family Asteraceae), endemic to the Galápagos archipelago, provides an ideal study system to test these hypotheses because of its species with markedly different leaf morphologies that occupy distinct climatic zones. In this study we tested the classic hypotheses that (1) climate constrains leaf size, (2) high climatic temperature variability selects for thermal generalists (i.e., the climate variability hypothesis), and (3) there is a trade-off between the breadth and rate of photosynthetic performance (i.e., jack-of-all-trades but master of none hypothesis). To do this we measured the leaf morphologies and photosynthetic temperature response curves of 11 Scalesia species. In support of a priori predictions, we found that small-leaved Scalesia species were more likely to occupy hotter and drier climates than large-leaved species, there was a positive relationship between climatic temperature variability and the breadth of photosynthetic performance, and photosynthetic performance was negatively correlated with photosynthetic breadth. Our study is among the first to provide evidence for the performance-breadth trade-off hypothesis in photosynthesis, suggesting that climate change may select for photosynthetic thermal generalists.


Asunto(s)
Asteraceae , Fotosíntesis , Animales , Fotosíntesis/fisiología , Temperatura , Cambio Climático , Hojas de la Planta , Plantas
3.
Front Zool ; 20(1): 4, 2023 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-36703215

RESUMEN

BACKGROUND: Large-scale species monitoring remains a significant conservation challenge. Given the ongoing biodiversity crisis, the need for reliable and efficient methods has never been greater. Drone-based techniques have much to offer in this regard: they allow access to otherwise unreachable areas and enable the rapid collection of non-invasive field data. Herein, we describe the development of a drone-based method for the estimation of population size in Galápagos marine iguanas, Amblyrhynchus cristatus. As a large-bodied lizard that occurs in open coastal terrain, this endemic species is an ideal candidate for drone surveys. Almost all Amblyrhynchus subspecies are Endangered or Critically Endangered according to the IUCN yet since several colonies are inaccessible by foot, ground- based methods are unable to address the critical need for better census data. In order to establish a drone-based approach to estimate population size of marine iguanas, we surveyed in January 2021 four colonies on three focal islands (San Cristobal, Santa Fe and Espanola) using three techniques: simple counts (the standard method currently used by conservation managers), capture mark-resight (CMR), and drone-based counts. The surveys were performed within a 4-day window under similar ambient conditions. We then compared the approaches in terms of feasibility, outcome and effort. RESULTS: The highest population-size estimates were obtained using CMR, and drone-based counts were on average 14% closer to CMR estimates-and 17-35% higher-than those obtained by simple counts. In terms of field-time, drone-surveys can be faster than simple counts, but image analyses were highly time consuming. CONCLUSION: Though CMR likely produces superior estimates, it cannot be performed in most cases due to lack of access and knowledge regarding colonies. Drone-based surveys outperformed ground-based simple counts in terms of outcome and this approach is therefore suitable for use across the range of the species. Moreover, the aerial approach is currently the only credible solution for accessing and surveying marine iguanas at highly remote colonies. The application of citizen science and other aids such as machine learning will alleviate the issue regarding time needed to analyze the images.

4.
Addict Biol ; 27(5): e13223, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36001424

RESUMEN

The use of areca nuts (areca) in the form of betel quids constitutes the fourth most common addiction in the world, associated with high risk for oral disease and cancer. Areca is a complex natural product, making it difficult to identify specific components associated with the addictive and carcinogenic properties. It is commonly believed that the muscarinic agonist arecoline is at the core of the addiction. However, muscarinic receptor activation is not generally believed to support drug-taking behaviour. Subjective accounts of areca use include descriptions of both sedative and stimulatory effects, consistent with the presence of multiple psychoactive agents. We have previously reported partial agonism of α4-containing nicotinic acetylcholine receptors by arecoline and subsequent inhibition of those receptors by whole areca broth. In the present study, we report the inhibition of nicotinic acetylcholine receptors and other types of neurotransmitter receptors with compounds of high molecular weight in areca and the ability of low molecular weight areca extract to activate GABA and glutamate receptors. We confirm the presence of a high concentration of GABA and glutamate in areca. Additionally, data also indicate the presence of a dopamine and serotonin transporter blocking activity in areca that could account for the reported stimulant and antidepressant activity. Our data suggest that toxic elements of high molecular weight may contribute to the oral health liability of betel quid use, while two distinct low molecular weight components may provide elements of reward, and the nicotinic activity of arecoline contributes to the physical dependence of addiction.


Asunto(s)
Conducta Adictiva , Receptores Nicotínicos , Areca , Arecolina/farmacología , Ácido gamma-Aminobutírico
5.
Sensors (Basel) ; 22(23)2022 Nov 23.
Artículo en Inglés | MEDLINE | ID: mdl-36501771

RESUMEN

Background: Golf swing performance in medium- to high-handicap players must be reliably measured to use this variable in both research studies and in applied settings. Nevertheless, there are no studies published on this topic and test−retest evidence is only available for low-handicap players. The aim of this study was to determine the number of attempts necessary to obtain a reliable measurement protocol for swing performance variables in medium- to high-handicap players. Methods: Ten amateur players (55.67 (13.64) years, 78.4 (11.4) kg, 1.75 (7.95) m) took part in a test−retest study in two experimental sessions one week apart. In each one, fifteen swings with a six iron and a driver were evaluated with a 3D Doppler tracking golf radar. Results: The results showed that variables related to side carry could not be reliably measured in medium- to high-handicap players in only fifteen trials (ICC < 0.26, SEM > 12.05 m and MDC > 33.41 m). The rest of the performance variables related to the club and ball trajectories could be reliably measured with a 3D Doppler radar with between seven and ten swings. Conclusions: At least seven swings are recommended for the driver and ten for the six iron to measure golf swing performance.


Asunto(s)
Golf , Análisis y Desempeño de Tareas , Reproducibilidad de los Resultados , Fenómenos Biomecánicos , Hierro , Movimiento
6.
Rev Med Chil ; 150(11): 1534-1539, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37358180

RESUMEN

Chronic coronary syndromes are usually considered uncommon in young women, related to slower progression of atherosclerotic coronary artery disease, have atypical clinical presentations, and experience less diagnostic investigation. Non-atherosclerotic causes of coronary artery disease should be considered in young women experiencing angina. We report a 25-year-old woman who consulted for five months of moderate exertion angina. Physical examination revealed a right carotid bruit and asymmetrical upper extremity peripheral pulses. Initial work-up and imaging allowed to diagnose aortitis with bilateral coronary ostial stenosis secondary to Takayasu's arteritis. The patient experienced an apparent clinical response to initial medical therapy. However, follow-up evaluation revealed persistence of significant ischemia and requirement for myocardial revascularization. A percutaneous coronary intervention was performed.


Asunto(s)
Enfermedad de la Arteria Coronaria , Arteritis de Takayasu , Femenino , Humanos , Adulto , Arteritis de Takayasu/complicaciones , Arteritis de Takayasu/diagnóstico por imagen , Arterias
7.
Rev Med Chil ; 149(5): 672-681, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-34751319

RESUMEN

Background The coronavirus disease (COVID-19) pandemic affected the prompt diagnosis and treatment of Acute myocardial infarction (AMI). AIM: To characterize the clinical profile of patients with AMI during the COVID-19 pandemic, comparing them with a historical cohort. MATERIAL AND METHODS: A case-control study of 96 patients with AMI transferred to a high-volume percutaneous coronary intervention (PCI) hospital between March and July 2020, and a historical cohort of 269 patients transferred during the same period in 2019. RESULTS: When comparing patients transferred during the pandemic with those of the historical cohort, the former were younger (63 ± 12 vs 68 ± 12 years, p < 0.01), had a higher frequency of hypertension (66 vs 45%, p < 0.01) and of smoking (40% vs 25%, p < 0.01). Also, during COVID-19 outbreak a higher proportion of patients had ST-elevation AMI consulting > 12 hours from the onset of symptoms (44 vs 0%, p < 0.01), a higher median door-to-device time (4 vs 3 hours, p < 0.01), a higher use of primary percutaneous coronary intervention (97 vs 71%, p < 0.01), and higher frequencies of cardiogenic shock (20 vs 4%, p < 0.01) and mechanical complications (10% vs 2%, p < 0.01). Patients during COVID pandemic had a higher thirty-day overall (20 vs 1.4%, p < 0.01) and cardiovascular mortality (13 vs 1%, p < 0.01). During the outbreak, 40% of patients had positive COVID-19 status, which was a predictor for thirty-day overall mortality (Risk ratio 2.90; 95% confidence intervals 1.14-7.36). CONCLUSIONS: During the pandemic patients with AMI exhibited delays in consultations and treatment, higher morbidity, and increased mortality. COVID-19 positivity was associated to worse thirty-day overall survival.


Asunto(s)
Angioplastia Coronaria con Balón , COVID-19 , Infarto del Miocardio , Intervención Coronaria Percutánea , Estudios de Casos y Controles , Electrocardiografía , Humanos , Infarto del Miocardio/epidemiología , Infarto del Miocardio/terapia , Pandemias , Pronóstico , Reperfusión , SARS-CoV-2 , Resultado del Tratamiento
8.
J Biol Chem ; 294(17): 6957-6971, 2019 04 26.
Artículo en Inglés | MEDLINE | ID: mdl-30824538

RESUMEN

The dopamine transporter (DAT) regulates dopamine neurotransmission via reuptake of dopamine released into the extracellular space. Interactions with partner proteins alter DAT function and thereby dynamically shape dopaminergic tone important for normal brain function. However, the extent and nature of these interactions are incompletely understood. Here, we describe a novel physical and functional interaction between DAT and the voltage-gated K+ channel Kv2.1 (potassium voltage-gated channel subfamily B member 1 or KCNB1). To examine the functional consequences of this interaction, we employed a combination of immunohistochemistry, immunofluorescence live-cell microscopy, co-immunoprecipitation, and electrophysiological approaches. Consistent with previous reports, we found Kv2.1 is trafficked to membrane-bound clusters observed both in vivo and in vitro in rodent dopamine neurons. Our data provide evidence that clustered Kv2.1 channels decrease DAT's lateral mobility and inhibit its internalization, while also decreasing canonical transporter activity by altering DAT's conformational equilibrium. These results suggest that Kv2.1 clusters exert a spatially discrete homeostatic braking mechanism on DAT by inducing a relative increase in inward-facing transporters. Given recent reports of Kv2.1 dysregulation in neurological disorders, it is possible that alterations in the functional interaction between DAT and Kv2.1 affect dopamine neuron activity.


Asunto(s)
Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Endocitosis , Canales de Potasio Shab/metabolismo , Animales , Dopamina/metabolismo , Femenino , Masculino , Mesencéfalo/citología , Mesencéfalo/metabolismo , Ratones , Ratones Endogámicos C57BL , Neuronas/metabolismo , Ratas , Ratas Sprague-Dawley
9.
Ecol Lett ; 22(7): 1072-1082, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30938488

RESUMEN

Neutral models are often used as null models, testing the relative importance of niche versus neutral processes in shaping diversity. Most versions, however, focus only on regional scale predictions and neglect local level contributions. Recently, a new formulation of spatial neutral theory was published showing an incompatibility between regional and local scale fits where especially the number of rare species was dramatically under-predicted. Using a forward in time semi-spatially explicit neutral model and a unique large-scale Amazonian tree inventory data set, we show that neutral theory not only underestimates the number of rare species but also fails in predicting the excessive dominance of species on both regional and local levels. We show that although there are clear relationships between species composition, spatial and environmental distances, there is also a clear differentiation between species able to attain dominance with and without restriction to specific habitats. We conclude therefore that the apparent dominance of these species is real, and that their excessive abundance can be attributed to fitness differences in different ways, a clear violation of the ecological equivalence assumption of neutral theory.


Asunto(s)
Biodiversidad , Ecología , Árboles , Ecosistema , Modelos Biológicos , Especificidad de la Especie
10.
J Biol Chem ; 291(34): 17510-22, 2016 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-27365397

RESUMEN

We previously reported that the vesicular monoamine transporter 2 (VMAT2) is physically and functionally coupled with Hsc70 as well as with the dopamine synthesis enzymes tyrosine hydroxylase (TH) and aromatic amino acid decarboxylase, providing a novel mechanism for dopamine homeostasis regulation. Here we expand those findings to demonstrate that Hsc70 physically and functionally interacts with TH to regulate the enzyme activity and synaptic vesicle targeting. Co-immunoprecipitation assays performed in brain tissue and heterologous cells demonstrated that Hsc70 interacts with TH and aromatic amino acid decarboxylase. Furthermore, in vitro binding assays showed that TH directly binds the substrate binding and carboxyl-terminal domains of Hsc70. Immunocytochemical studies indicated that Hsc70 and TH co-localize in midbrain dopaminergic neurons. The functional significance of the Hsc70-TH interaction was then investigated using TH activity assays. In both dopaminergic MN9D cells and mouse brain synaptic vesicles, purified Hsc70 facilitated an increase in TH activity. Neither the closely related protein Hsp70 nor the unrelated Hsp60 altered TH activity, confirming the specificity of the Hsc70 effect. Overexpression of Hsc70 in dopaminergic MN9D cells consistently resulted in increased TH activity whereas knockdown of Hsc70 by short hairpin RNA resulted in decreased TH activity and dopamine levels. Finally, in cells with reduced levels of Hsc70, the amount of TH associated with synaptic vesicles was decreased. This effect was rescued by addition of purified Hsc70. Together, these data demonstrate a novel interaction between Hsc70 and TH that regulates the activity and localization of the enzyme to synaptic vesicles, suggesting an important role for Hsc70 in dopamine homeostasis.


Asunto(s)
Dopamina/metabolismo , Neuronas Dopaminérgicas/metabolismo , Proteínas del Choque Térmico HSC70/metabolismo , Vesículas Sinápticas/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , Animales , Línea Celular , Chaperonina 60/genética , Chaperonina 60/metabolismo , Dopamina/genética , Neuronas Dopaminérgicas/citología , Proteínas del Choque Térmico HSC70/genética , Homeostasis/fisiología , Masculino , Ratones , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Unión Proteica/fisiología , Dominios Proteicos , Ratas , Ratas Sprague-Dawley , Vesículas Sinápticas/genética , Tirosina 3-Monooxigenasa/genética
11.
J Neurochem ; 136(6): 1270-1283, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26611352

RESUMEN

Parkinson's disease (PD) is a debilitating condition that is caused by a relatively specific degeneration of dopaminergic (DAergic) neurons of the substantia nigra pars compacta. L-DOPA was introduced as a viable treatment option for PD over 40 years ago and still remains the most common and effective therapy for PD. Though the effects of L-DOPA to augment striatal DA production are well known, little is actually known about how L-DOPA alters the kinetics of DA neurotransmission that contribute to its beneficial and adverse effects. In this study, we examined the effects of L-DOPA administration (50 mg/kg carbidopa + 0, 100, and 250 mg/kg L-DOPA) on regional electrically stimulated DA response kinetics using fast-scan cyclic voltammetry in anesthetized rats. We demonstrate that L-DOPA enhances DA release in both the dorsal striatum (D-STR) and nucleus accumbens (NAc), but surprisingly causes a delayed inhibition of release in the D-STR. In both regions, L-DOPA progressively attenuated reuptake kinetics, predominantly through a decrease in Vmax . These findings have important implications on understanding the pharmacodynamics of L-DOPA, which may be informative for understanding its therapeutic effects and also common side effects like L-DOPA-induced dyskinesias (LID). L-DOPA is commonly used to treat Parkinsonian symptoms, but little is known about how it affects presynaptic DA neurotransmission. Using in vivo fast-scan cyclic voltammetry, we show L-DOPA inhibits DA reuptake in a region-specific and dose-dependent manner, and L-DOPA has paradoxical effects on release. These findings may be important when considering mechanisms for L-DOPA's therapeutic benefits and adverse side-effects.

12.
Artículo en Inglés | MEDLINE | ID: mdl-38565388

RESUMEN

While there is extensive research on alcohol dependence, the factors that make an individual vulnerable to developing alcoholism haven't been explored much. In this study, we aim to investigate how neonatal exposure to sex hormones affects alcohol intake and the regulation of the mesolimbic pathway in adulthood. The study aimed to investigate the impact of neonatal exposure to a single dose of testosterone propionate (TP) or estradiol valerate (EV) on ethanol consumption in adult rats. The rats were subjected to a two-bottle free-choice paradigm, and the content of dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens (NAcc) was measured using HPLC-ED. The expression of critical DA-related proteins in the mesolimbic pathway was evaluated through RT-qPCR and western blot analysis. Supraphysiological neonatal exposure to EV or TP resulted in increased ethanol intake over four weeks in adulthood. In addition, the DA and DOPAC content was reduced and increased in the NAcc of EV and TP-treated rats, and ß-endorphin content in the hypothalamus decreased in EV-treated rats. The VTA µ receptor and DA type 2 form short receptor (D2S) expression were significantly reduced in EV and TP male rats. Finally, in an extended 6-week protocol, the increase in ethanol consumption induced by EV was mitigated during the initial two hours post-naloxone injection. Neonatal exposure to sex hormones is a detrimental stimulus for the brain, which can facilitate the development of addictive behaviors, including alcohol use disorder.


Asunto(s)
Ácido 3,4-Dihidroxifenilacético , Consumo de Bebidas Alcohólicas , Animales Recién Nacidos , Dopamina , Estradiol , Núcleo Accumbens , Propionato de Testosterona , Animales , Masculino , Consumo de Bebidas Alcohólicas/metabolismo , Ratas , Núcleo Accumbens/metabolismo , Núcleo Accumbens/efectos de los fármacos , Estradiol/farmacología , Propionato de Testosterona/farmacología , Propionato de Testosterona/administración & dosificación , Dopamina/metabolismo , Ácido 3,4-Dihidroxifenilacético/metabolismo , Femenino , Etanol/farmacología , Etanol/administración & dosificación , Hormonas Esteroides Gonadales/metabolismo , Ratas Sprague-Dawley
13.
J Trace Elem Med Biol ; 84: 127417, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38479042

RESUMEN

BACKGROUND: Lead (Pb), cadmium (Cd) and mercury (Hg) are toxic trace elements that represent a public health problem as risk factors for cardiovascular disease and hypertension (HT) and could also contribute to the development of resistant hypertension (rHT) AIMS: To compare the blood concentrations of Pb, Cd and Hg in subjects with resistant and non-resistant HT and to define whether there is a relationship between its levels and rHT. METHODS: Cross-sectional study. Subjects aged ≥ 21 to ≤ 80 years with a body mass index < 40 kg/m2 were recruited on a discretionary basis from October 2001 to October 2004 in a hypertension unit of a tertiary hospital amongst those sent to the hypertension unit by their family physician. Resistant hypertension was defined according to the American Heart Association (AHA) criteria. Whole blood concentrations of Cd, Pb and Hg were measured by electrothermal atomic absorption spectrometry. RESULTS: 46 out of 73 included subjects (63%) suffered from rHT. Blood Pb median: HT 3.9 (IQR 2.7-5.2) vs. rHT 3.6 (IQR 2.8-6.0) µg/dL (p=0.941). Blood Cd median: HT 0.07 (IQR 0.07-0.80) vs. rHT 0.30 (IQR 0.07-0.65) µg/L (p=0.681). Blood Hg median: HT 7.9 (IQR 5.8-12.9) vs. rHT 7.3 (IQR 4.6-13.3) µg/L (p=0.611). Considering the 75th percentile of each element (Pb: 5.55 µg/dL, Cd: 0.75 µg/L, Hg: 13.15 µg/L), a multiple logistic regression analysis (adjusted for age, BMI, diabetes mellitus, clearance of creatinine and only for Cd the smoking habit) showed an OR = 3.44 (0.84-14.10, p=0.086) for Pb, OR = 1.80 (0.39-8.24, p=0.451), for Cd and OR = 2.31 (0.59-9.14, p=0.232) for Hg. Moreover, the stratified analyses showed that men with Pb ≥5.55 µg/dL have a 14 times higher risk of suffering from rHT (p=0.026). Interestingly, a 9-fold increased risk was found for non-obese subjects with elevated Pb levels, above 5.55 µg/dL (p=0.029). Also in men, the probability of suffering from rHT was more than 7 times higher if Cd levels were ≥ 0.75 µg/L (p=0.076). Most smokers had higher Cd levels, with a high risk of suffering from rHT (ORa 12.6 (0.8-200.2), p=0.072). CONCLUSION: A higher blood Pb levels, defined by the 75th percentile (Pb ≥ 5.55 µg/dL), is associated with a greater risk of suffering from rHT and to a lesser extent in the case of Cd and Hg.


Asunto(s)
Cadmio , Hipertensión , Plomo , Mercurio , Humanos , Mercurio/sangre , Plomo/sangre , Cadmio/sangre , Masculino , Hipertensión/sangre , Hipertensión/inducido químicamente , Persona de Mediana Edad , Femenino , Factores de Riesgo , Estudios Transversales , Anciano , Adulto
14.
Ecol Evol ; 14(2): e10994, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38357592

RESUMEN

Invasive alien species are among the most pervasive threats to biodiversity. Invasive species can cause catastrophic reductions in populations of native and endemic species and the collapse of ecosystem function. A second major global conservation concern is the extirpation of large-bodied mobile animals, including long-distance migrants, which often have keystone ecological roles over extensive spatial extents. Here, we report on a potentially catastrophic synergy between these phenomena that threatens the endemic biota of the Galapagos Archipelago. We used GPS telemetry to track 140 migratory journeys by 25 Western Santa Cruz Island Galapagos tortoises. We plotted the spatial interaction between tortoise migrations and recently established non-native forest dominated by the invasive tree Cedrela odorata (Cedrela forest). We qualified (a) the proportion of migratory journeys that traversed Cedrela forest, and (b) the probability that this observed pattern occurred by chance. Tortoise migrations were overwhelmingly restricted to small corridors between Cedrela forest blocks, indicating clear avoidance of those blocks. Just eight of 140 migrations traversed extensive Cedrela stands. Tortoises avoid Cedrela forest during their migrations. Further expansion of Cedrela forest threatens long-distance migration and population viability of critically endangered Galapagos tortoises. Applied research to determine effective management solutions to mitigate Cedrela invasion is a high priority.

15.
Artículo en Inglés | MEDLINE | ID: mdl-38692837

RESUMEN

Neotropical ecosystems are renowned for numerous examples of adaptive radiation in both plants and animals resulting in high levels of biodiversity and endemism. However, we still lack a comprehensive review of the abiotic and biotic factors that contribute to these adaptive radiations. To fill this gap, we delve into the geological history of the region, including the role of tectonic events such as the Andean uplift, the formation of the Isthmus of Panama, and the emergence of the Guiana and Brazilian Shields. We also explore the role of ecological opportunities created by the emergence of new habitats, as well as the role of key innovations, such as novel feeding strategies or reproductive mechanisms. We discuss different examples of adaptive radiation, including classic ones like Darwin's finches and Anolis lizards, and more recent ones like bromeliads and lupines. Finally, we propose new examples of adaptive radiations mediated by ecological interactions in their geological context. By doing so, we provide insights into the complex interplay of factors that contributed to the remarkable diversity of life in the Neotropics and highlight the importance of this region in understanding the origins of biodiversity.

16.
Sensors (Basel) ; 14(1): 403-15, 2013 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-24379046

RESUMEN

The physical properties and the effect of effective surface area (ESA) on the sensing properties of tin dioxide [SnO2] thin films in air and propane [C3H8] atmosphere as a function of operating temperature and gas concentration have been studied in this paper. SnO2 thin films with different estimated thicknesses (50, 100 and 200 nm) were deposited on glass substrates by the chemical spray technique. Besides, they were prepared at two different deposition temperatures (400 and 475 °C). Tin chloride [SnCl4∙5H2O] with 0.2 M concentration value and ethanol [C2H6O] were used as tin precursor and solvent, respectively. The morphological, and structural properties of the as-prepared films were analyzed by AFM and XRD, respectively. Gas sensing characteristics of SnO2 thin solid films were measured at operating temperatures of 22, 100, 200, and 300 °C, and at propane concentration levels (0, 5, 50, 100, 200, 300, 400, and 500 ppm). ESA values were calculated for each sample. It was found that the ESA increased with the increasing thickness of the films. The results demonstrated the importance of the achieving of a large effective surface area for improving gas sensing performance. SnO2 thin films deposited by spray chemical were chosen to study the ESA effect on gas sensing properties because their very rough surfaces were appropriate for this application.

17.
Sensors (Basel) ; 13(3): 3432-44, 2013 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-23482091

RESUMEN

Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well.


Asunto(s)
Cromo/química , Propano/aislamiento & purificación , Rutenio/química , Óxido de Zinc/química , Catálisis , Geles , Vidrio/química , Humanos , Transición de Fase , Soluciones/química , Propiedades de Superficie , Difracción de Rayos X
18.
ACS Omega ; 8(45): 43051-43059, 2023 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-38024694

RESUMEN

The human trace amine-associated receptor (hTAAR1), a G protein-coupled receptor, has been postulated as a new target in the treatment of neuropsychiatric conditions. The mechanism associated with activation or inactivation by agonists or antagonists in hTAAR1 and other GPCRs has not yet been fully elucidated. In this study, we combined computational methods including homology modeling, docking, and molecular dynamic simulations to reveal novel conformational changes associated with agonist and antagonist interactions in hTAAR1. Our findings suggest a differential cascade of coordinated movements based on the presence of either an agonist or antagonist and primarily involving the second extracellular loop, transmembrane domain 5, and the third intracellular domains of hTAAR1. Our study provides an opportunity to predict the effects on new ligands with agonistic or antagonistic activity at hTAAR1 based on the reported conformational changes.

19.
Ecology ; 104(9): e4135, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37438994

RESUMEN

We compiled and presented a dataset for all timber species reported in the Amazon region from all nine South American Amazonian countries. This was based on official information from every country, as well as from two substantial scientific references. We verified the standard taxonomic names from each individual source, using the Taxonomic Name Resolution Service (TNRS) and considered all Amazonian tree species with diameter at breast height (DBH) ≥10 cm. We also obtained estimates of the current population size for most species from a published approach based on data from 1900 tree inventory plots (1-ha each) distributed across the Amazon region and part from the Amazon Tree Diversity Network (ATDN). We then identified the hyperdominant timber species. In addition, we overlapped our timber species list with data for species that are used for commercial purposes, according to the International Tropical Timber Organization (ITTO), the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the International Union for Conservation of Nature (IUCN) taxa assessment and Red List categories. Finally, we also included IUCN Red List categories based on combined deforestation, and climate change scenarios for these species. Our final Amazonian timber species dataset contains 1112 unique species records, which belong to 337 genera and 72 families from the lowland Amazonian rainforest, with associated information related to population, conservation, and trade status of each species. The authors of this research expect that the information provided will be useful to strengthen the public forestry policies of the Amazon countries, inform ecological studies, as well for forest management purposes. The data are released under the Creative Commons Attribution 4.0 International license.


Asunto(s)
Comercio , Internacionalidad , Humanos , Árboles , Bosques , Agricultura Forestal , Conservación de los Recursos Naturales , Clima Tropical
20.
Artículo en Inglés | MEDLINE | ID: mdl-37597150

RESUMEN

In this study, we report on the synthesis of ternary photocatalysts comprising TiO2/SnO2/g-C3N4 for the degradation of ciprofloxacin (CIP) in water. SnO2 nanoparticles were synthesized via the sol-gel method, while g-C3N4 was obtained through melamine calcination. Commercial TiO2 and SnO2 nanopowders were also used. The heterojunctions were synthesized via the wet impregnation method. The photocatalysts were characterized via various techniques, including XRD, TEM, STEM, FTIR, N2 adsorption, UV-Vis DR, and hole tests. Photocatalytic degradation tests of CIP were carried out under UV, visible, and solar radiation. The P25/npA/g-C3N4 (90/10) material exhibited the best performance, achieving CIP degradation of over 97%. The synthesized materials demonstrated excellent initial adsorption of CIP, around 30%, which facilitated subsequent degradation. Notably, the CIP photocatalytic degradation tests performed under solar radiation showed a synergistic effect between the base materials and carbon nitride in highly energetic environments. These results highlight the effectiveness of ternary photocatalysts TiO2/SnO2/g-C3N4 for CIP degradation, particularly under solar radiation.

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