Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 297
Filtrar
1.
Phys Rev Lett ; 132(14): 142502, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38640383

RESUMEN

A precision measurement of the ß^{+} decay of ^{8}B was performed using the Beta-decay Paul Trap to determine the ß-ν angular correlation coefficient a_{ßν}. The experimental results were combined with new ab initio symmetry-adapted no-core shell-model calculations to yield the second-most precise measurement from Gamow-Teller decays, a_{ßν}=-0.3345±0.0019_{stat}±0.0021_{syst}. This value agrees with the standard model value of -1/3 and improves uncertainties in ^{8}B by nearly a factor of 2. By combining results from ^{8}B and ^{8}Li, a tight limit on tensor current coupling to right-handed neutrinos was obtained. A recent global evaluation of all other precision ß decay studies suggested a nonzero value for right-handed neutrino coupling in contradiction with the standard model at just above 3σ. The present results are of comparable sensitivity and do not support this finding.

2.
J Hazard Mater ; 466: 133504, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38310848

RESUMEN

This study aims to evaluate the role of indigenous microorganisms in the mobilization of potentially toxic elements (PTE) and rare-earth elements (REE), the influence of the bioavailability of carbon sources that might boost microbial leaching, and the generation of neutral/alkaline mine drainage from alkaline tailings. These tailings, with significant concentrations of total organic carbon (TOC), were mainly colonized by bacteria belonging to the genera Sphingomonas, Novosphingobium and Solirubrobacter, and fungi of the genera Alternaria, Sarocladium and Aspergillus. Functionality analysis suggests the capability of these microorganisms to leach PTE and REE. Bio-/leaching tests confirmed the generation of neutral mine drainage, the influence of organic substrate, and the leaching of higher concentrations of PTE and REE due to the production of organic acids and siderophores by indigenous microorganisms. In addition, this study offers some insights into a sustainable alternative for reprocessing PMC alkaline tailings to recover REE.


Asunto(s)
Metales de Tierras Raras , Metales de Tierras Raras/metabolismo , Bacterias/metabolismo , Carbono/metabolismo
6.
Sci Total Environ ; 885: 163526, 2023 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-37116802

RESUMEN

Chemical passive treatment systems used to remediate acid mine drainage has been evaluated based mainly on the reactivity of the chemical alkaline reagents, overlooking the activity of the microorganisms that proliferate in these artificial ecosystems. In this study, the bacterial communities of a unique passive treatment system known as BDAS (Barium carbonate Dispersed Alkaline Substrate) were investigated using 16S rRNA gene metagenomic sequencing combined with hydrochemical characterization of the AMD and phenotypic characterization of biogenic precipitates. According to the hydrochemical characterization, the water quality improved as the water progressed through the system, with a drastic increase in the pH (up to alkaline conditions) and total organic carbon, as well as the removal of main contaminants such as Ca2+, SO42-, Fe3+, Al3+, and Mn2+. These environmental changes resulted in an increase in bacterial diversity (richness) after the inlet and in the shift of the bacterial communities from chemoautotrophs (e.g., Ferrovum and Acidiphilum) to chemoheterotrophs (e.g., Brevundimonas and Geobacter). Some of these taxa harbour potential to immobilize metals, aiding in the treatment of the water. One of the mechanisms involved in the immobilization of metals is microbially induced calcium carbonate precipitation, which seems to occur spontaneously in BDAS. The production of biofilm was also observed in most parts of the system, except in the inlet, helping with the removal of metals. However, in the long run, the build-up of biofilm and precipitation of metals could clog (i.e., biofouling) the pores of the matrix, reducing the treatment efficiency. Potential human pathogens (e.g. Legionella) were also detected in BDAS indicating the need for a treatment step at the end of the system to remove pathogenic microorganisms. These findings present a new perspective of the bacterial communities and their effects (both positively and negatively) in a chemical passive treatment system.


Asunto(s)
Ecosistema , Contaminantes Químicos del Agua , Humanos , ARN Ribosómico 16S/genética , Contaminantes Químicos del Agua/análisis , Metales , Ácidos
7.
Phys Rev Lett ; 131(26): 262701, 2023 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-38215364

RESUMEN

Nuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The ß-decaying isomer ^{128m}Sb was identified as potentially impactful since the ß-decay pathway along the A=128 isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the ^{128}Sb isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of -84564.8(25) keV and -84608.8(21) keV, respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of ^{128m}Sb in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process.

8.
Chemosphere ; 307(Pt 2): 135922, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35940413

RESUMEN

Natural or industrial hexavalent chromium water pollution continues to be a worldwide unresolved threat. Today, there is intense research on new active and cost-effective sorbents for Cr(VI), but most still exhibit a critical limitation: their powdered nature makes their recovery from water cost and energy consuming. In this work, Al(OH)3, MIL-88-B(Fe), and UiO-66-NH2 Cr(VI) sorbents were immobilized into a poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymeric substrate to develop an easily reactivable and reusable water filtering technology. The immobilization of the sorbents into the PVDF-HFP porous matrix modified the macro and meso-porous structure of the polymeric matrix, tuning in parallel its wettability. Although a partial blocking of the Cr(VI) adsorptive capacity was observed for of Al(OH)3 and MIL-88-B(Fe) when immobilized into composite membranes, PVDF-HFP/UiO-66-NH2 filter (i) exceeded the full capacity of the non-immobilized sorbent to trap Cr(VI), (ii) could be reactivated and reusable, and (iii) it was fully functional when applied in real water effluents.


Asunto(s)
Contaminantes Químicos del Agua , Agua , Adsorción , Cromo/análisis , Polímeros de Fluorocarbono , Estructuras Metalorgánicas , Ácidos Ftálicos , Polivinilos , Contaminantes Químicos del Agua/análisis
9.
Microbiome ; 10(1): 131, 2022 08 23.
Artículo en Inglés | MEDLINE | ID: mdl-35996183

RESUMEN

BACKGROUND: Top-soil microbiomes make a vital contribution to the Earth's ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents. RESULTS: The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa's top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation. CONCLUSION: This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change. Video Abstract.


Asunto(s)
Microbiota , Suelo , Biodiversidad , Clima Desértico , Ecosistema , Microbiota/genética , Suelo/química , Microbiología del Suelo
10.
Bioelectrochemistry ; 146: 108157, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35594731

RESUMEN

This work reports the first dual magnetic beads (MBs) assisted immunoplatform for the simultaneous determination of BAFF (B cell activation factor) and APRIL (a proliferation-induced ligand), two cytokines related to immunity and tumour invasion, growth and metastasis. The electrochemical immunoplatform involves sandwich-type immunoassays implemented on magnetic microparticles functionalized with neutravidin (NA-MBs) or carboxylic groups (HOOC-MBs), and amperometric detection (Eapp =  - 0.20 V vs. Ag pseudo-reference electrode) at screen-printed dual carbon electrodes (SPdCE) using the H2O2/hydroquinone (HQ) system. The developed immunosensors provide improved sensitivity, with LOD values of 0.33 and 16.4 pg mL-1 for BAFF and APRIL, respectively, and much shorter assay time that those claimed for ELISA kits and allow their simultaneous determination. The dual immunosensor permits discrimination between healthy individuals and patients diagnosed with Systemic Lupus Erythematosus (SLE) or colorectal cancer (CRC) through the determination of both cytokines in 100-times diluted human sera with results in agreement with those provided by the individual ELISA methodologies.


Asunto(s)
Enfermedades Autoinmunes , Técnicas Biosensibles , Citocinas , Neoplasias , Enfermedades Autoinmunes/diagnóstico , Técnicas Biosensibles/métodos , Citocinas/análisis , Técnicas Electroquímicas , Humanos , Peróxido de Hidrógeno , Inmunoensayo/métodos , Neoplasias/diagnóstico
11.
J Visc Surg ; 159(3): 212-221, 2022 06.
Artículo en Inglés | MEDLINE | ID: mdl-35599158

RESUMEN

Twenty-seven experts under the aegis of the French Association of Surgery (AFC) offer this reference system with formalized recommendations concerning the performance of right colectomy by robotic approach (RRC). For RRC, experts suggest patient installation in the so-called "classic" or "suprapubic" setup. For patients undergoing right colectomy for a benign pathology or cancer, RRC provides no significant benefit in terms of intra-operative blood loss, intra-operative complications or conversion rate to laparotomy compared to laparoscopy. At the same time, RRC is associated with significantly longer operating times. Data from the literature are insufficient to define whether the robot facilitates the performance of an intra-abdominal anastomosis, but the robotic approach is more frequently associated with an intra-abdominal anastomosis than the laparoscopic approach. Experts also suggest that RRC offers a benefit in terms of post-operative morbidity compared to right colectomy by laparotomy. No benefit is retained in terms of mortality, duration of hospital stay, histological results, overall survival or disease-free survival in RRC performed for cancer. In addition, RRC should not be performed based on the cost/benefit ratio, since RRC is associated with significantly higher costs than laparoscopy and laparotomy. Future research in the field of RRC should consider the evaluation of patient-targeted parameters such as pain or quality of life and the technical advantages of the robot for complex procedural steps, as well as surgical and oncological results.


Asunto(s)
Neoplasias del Colon , Laparoscopía , Procedimientos Quirúrgicos Robotizados , Colectomía/métodos , Neoplasias del Colon/cirugía , Humanos , Laparoscopía/métodos , Tiempo de Internación , Tempo Operativo , Calidad de Vida , Estudios Retrospectivos , Procedimientos Quirúrgicos Robotizados/métodos , Resultado del Tratamiento
12.
J Visc Surg ; 159(1S): S28-S34, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35131151

RESUMEN

Bariatric surgery can induce changes in digestive motility that are de novo or secondary to an improvement or aggravation of previous disorders due to obesity. Alterations of digestive motility are frequently part of the mechanism of action and a result of surgery. They are not rare and they are not always associated with an increase in weight loss but can lead to the negative consequences on quality of life, which are more or less reversible as a real surgical complication. Knowledge of these complications has become essential, especially in this period when bariatric surgery often concerns patients who have already undergone an operation. Thus, the changes in digestive motility after bariatric surgery and the complications that may result from them must be known and considered to adapt surgical techniques to each patient, both in the case of a first intervention and in the case of a reoperation, which is becoming more and more frequent. The objective of this review is to synthesize alterations of esophageal and gastro-intestinal motility secondary to bariatric surgical procedures.


Asunto(s)
Cirugía Bariátrica , Derivación Gástrica , Gastroplastia , Laparoscopía , Obesidad Mórbida , Cirugía Bariátrica/efectos adversos , Gastrectomía/métodos , Derivación Gástrica/métodos , Gastroplastia/métodos , Humanos , Laparoscopía/métodos , Obesidad Mórbida/complicaciones , Obesidad Mórbida/cirugía , Calidad de Vida , Reoperación , Resultado del Tratamiento
13.
Anal Methods ; 13(36): 4131-4142, 2021 09 23.
Artículo en Inglés | MEDLINE | ID: mdl-34554152

RESUMEN

In this study, we aimed to validate and apply a quick and easy extraction method for the simultaneous determination of 27 pesticide residues at trace levels in agricultural samples (soil, fruit, and leaf) to monitor the presence of these contaminants released from reclaimed water. The procedure was based on a salting-out extraction method with acidified acetonitrile, followed by a dispersive solid-phase extraction (d-SPE) clean-up step applying the C18 sorbent. Ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS) was used for identification and quantification of the target analytes. This methodology provided recovery values higher than 70%, for all pesticides and matrices evaluated in the study, except for propamocarb in soil samples (35%). Repeatability and reproducibility results, calculated as relative standard deviations (RSD, %), ranged between 1% and 18% in both cases. No remarkable matrix effects were observed for vegetable samples, except for thiamethoxam in red cabbage, and hexythiazox in carrot and leaves (between 30 and 40%). Soil samples showed a moderate matrix effect (between 21 and 35%) for more than 80% of the compounds. Monitoring pesticide residues found in agricultural samples irrigated with contaminated reclaimed water under controlled conditions revealed the efficacy of the proposed method. Three common vegetables were grown to evaluate the different migration and distribution rates in crops and soil. Pesticide accumulation in the different parts of the crop (soil, fruit, and leaves) and the potential human exposure to pesticides through daily intake were also discussed.


Asunto(s)
Residuos de Plaguicidas , Cromatografía Liquida , Humanos , Residuos de Plaguicidas/análisis , Reproducibilidad de los Resultados , Espectrometría de Masas en Tándem , Agua
15.
Front Zool ; 18(1): 32, 2021 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-34183024

RESUMEN

Parity mode (oviparity/viviparity) importantly affects the ecology, morphology, physiology, biogeography and evolution of organisms. The main hypotheses explaining the evolution and maintenance of viviparity are based on bioclimatic predictions and also state that the benefits of viviparity arise during the reproductive period. We identify the main climatic variables discriminating between viviparous and oviparous Eurasian common lizard (Zootoca vivipara) occurrence records during the reproductive period and over the entire year.Analyses based on the climates during the reproductive period show that viviparous clades inhabit sites with less variable temperature and precipitation. On the contrary, analyses based on the annual climates show that viviparous clades inhabit sites with more variable temperatures.Results from models using climates during reproduction are in line with the "selfish-mother hypothesis", which can explain the success of viviparity, the maintenance of the two reproductive modes, and why viviparous individuals cannot colonize sites inhabited by oviparous ones (and vice versa). They suggest that during the reproductive period viviparity has an adaptive advantage over oviparity in less risky habitats thanks to the selfish behaviour of the mothers. Moreover, the results from both analyses stress that hypotheses about the evolution and maintenance of viviparity need to be tested during the reproductive period.

16.
BJS Open ; 5(3)2021 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-34097005

RESUMEN

BACKGROUND: Local excision (LE) after chemoradiotherapy is a new option in low rectal cancer, but morbidity has never been compared prospectively with total mesorectal excision (TME). Early and late morbidity were compared in patients treated either by LE or TME after neoadjuvant chemoradiotherapy for rectal cancer. METHOD: This was a post-hoc analysis from a randomized trial. Patients with clinical T2/T3 low rectal cancer with good response to the chemoradiotherapy and having either LE, LE with eventual completion TME, or TME were considered. Early (1 month) and late (2 years) morbidities were compared between the three groups. RESULTS: There were no deaths following surgery in any of the three groups. Early surgical morbidity (20 per cent LE versus 36 per cent TME versus 43 per cent completion TME, P = 0.025) and late surgical morbidity (4 per cent versus 33 per cent versus 57 per cent, P < 0.001) were significantly lower in the LE group than in the TME or the completion TME group. of LE, was associated with the lowest rate of early (10 versus 18 versus 21 per cent, P = 0.217) and late medical morbidities (0 versus 7 versus 7 per cent, P = 0.154), although this did not represent a significant difference between the groups. The severity of overall morbidity was significantly lower at 2 years after LE compared with TME or completion TME (4 versus 28 versus 43 per cent grade 3-5, P < 0.001). CONCLUSION: The rate of surgical complications after neoadjuvant chemoradiotherapy in the LE group was half that of TME group at 1 month and 10 times lower at 2 years. LE is a safe approach for organ preservation and should be considered as an alternative to watch-and-wait in complete clinical responders and to TME in subcomplete responders.


Asunto(s)
Neoplasias del Recto , Quimioradioterapia/efectos adversos , Humanos , Morbilidad , Estadificación de Neoplasias , Neoplasias del Recto/patología , Neoplasias del Recto/terapia , Resultado del Tratamiento
17.
Phys Rev Lett ; 126(4): 042501, 2021 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-33576685

RESUMEN

We report high-precision mass measurements of ^{50-55}Sc isotopes performed at the LEBIT facility at NSCL and at the TITAN facility at TRIUMF. Our results provide a substantial reduction of their uncertainties and indicate significant deviations, up to 0.7 MeV, from the previously recommended mass values for ^{53-55}Sc. The results of this work provide an important update to the description of emerging closed-shell phenomena at neutron numbers N=32 and N=34 above proton-magic Z=20. In particular, they finally enable a complete and precise characterization of the trends in ground state binding energies along the N=32 isotone, confirming that the empirical neutron shell gap energies peak at the doubly magic ^{52}Ca. Moreover, our data, combined with other recent measurements, do not support the existence of a closed neutron shell in ^{55}Sc at N=34. The results were compared to predictions from both ab initio and phenomenological nuclear theories, which all had success describing N=32 neutron shell gap energies but were highly disparate in the description of the N=34 isotone.

18.
Urol Case Rep ; 36: 101560, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33489767

RESUMEN

A case affected by a seminal vesicles secondary tumor to diffuse large B-cell lymphoma is reported. Seminal vesicles neoplasms are scarce, and they can be classified into primary or secondary. The most common case is their involvement by extension of adjacent tumors, which are clinically nonspecific. In the case presented herein, the patient complained of oliguria, constipation and perineal pain, where imaging methods revealed the growth of both seminal vesicles. Pathological examination revealed infiltration of seminal vesicles by diffuse large B-cell lymphoma. In view of this clinical event, we briefly reviewed literature related to the involvement of seminal vesicles tumor.

20.
Phys Rev Lett ; 123(23): 239905, 2019 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-31868474

RESUMEN

This corrects the article DOI: 10.1103/PhysRevLett.120.032701.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...