Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Proc (Bayl Univ Med Cent) ; 36(2): 205-207, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36876252

RESUMO

Tracheoesophageal fistula is uncommon in adults but can cause devastating aspiration events. Herein, we report a unique case of a tracheoesophageal fistula in an adult that presented intraoperatively. The patient did not have any prior history of abdominal or thoracic surgery and was not intubated for a prolonged period of time. The diagnosis, subsequent hospital course, and recommendations for early recognition of this rare condition are discussed.

3.
4.
Front Microbiol ; 12: 733244, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34867849

RESUMO

With long-term missions to Mars and beyond that would not allow resupply, a self-sustaining Bioregenerative Life Support System (BLSS) is essential. Algae are promising candidates for BLSS due to their completely edible biomass, fast growth rates and ease of handling. Extremophilic algae such as snow algae and halophilic algae may also be especially suited for a BLSS because of their ability to grow under extreme conditions. However, as indicated from over 50 prior space studies examining algal growth, little is known about the growth of algae at close to Mars-relevant pressures. Here, we explored the potential for five algae species to produce oxygen and food under low-pressure conditions relevant to Mars. These included Chloromonas brevispina, Kremastochrysopsis austriaca, Dunaliella salina, Chlorella vulgaris, and Spirulina plantensis. The cultures were grown in duplicate in a low-pressure growth chamber at 670 ± 20 mbar, 330 ± 20 mbar, 160 ± 20 mbar, and 80 ± 2.5 mbar pressures under continuous light exposure (62-70 µmol m-2 s-1). The atmosphere was evacuated and purged with CO2 after sampling each week. Growth experiments showed that D. salina, C. brevispina, and C. vulgaris were the best candidates to be used for BLSS at low pressure. The highest carrying capacities for each species under low pressure conditions were achieved by D. salina at 160 mbar (30.0 ± 4.6 × 105 cells/ml), followed by C. brevispina at 330 mbar (19.8 ± 0.9 × 105 cells/ml) and C. vulgaris at 160 mbar (13.0 ± 1.5 × 105 cells/ml). C. brevispina, D. salina, and C. vulgaris all also displayed substantial growth at the lowest tested pressure of 80 mbar reaching concentrations of 43.4 ± 2.5 × 104, 15.8 ± 1.3 × 104, and 57.1 ± 4.5 × 104 cells per ml, respectively. These results indicate that these species are promising candidates for the development of a Mars-based BLSS using low pressure (∼200-300 mbar) greenhouses and inflatable structures that have already been conceptualized and designed.

5.
J Orthop Surg Res ; 14(1): 359, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31718674

RESUMO

BACKGROUND: Socio-demographic factors have been suggested to contribute to differences in healthcare utilization for several elective orthopedic procedures. Reports on disparities in utilization of orthopedic trauma procedures remain limited. The purpose of our study is to assess the roles of clinical and socio-demographic variables in utilization of operative fixation of calcaneus fractures in the USA. METHODS: The National Inpatient Sample (NIS) dataset was used to analyze all patients from 2005 to 2014 with closed calcaneal fractures. Multivariate logistic regression analyses were performed to evaluate the impact of clinical and socio-demographic variables on the utilization of surgical versus non-surgical treatment. RESULTS: A total of 17,156 patients with closed calcaneus fractures were identified. Operative treatment was rendered in 7039 patients (41.03%). A multivariate logistic regression demonstrated multiple clinical and socio-demographic factors to significantly influence the utilization of surgical treatment including age, gender, insurance status, race/ethnicity, income, diabetes, peripheral vascular disease, psychosis, drug abuse, and alcohol abuse (p <  0.05). In addition, hospital size and hospital type (teaching versus non-teaching) showed a statistically significant difference (p <  0.05). CONCLUSIONS: Besides different clinical variables, we identified several socio-demographic factors influencing the utilization of surgical treatment of calcaneus fractures in the US patient population. Further studies need to identify the specific patient-related, provider-related, and system-related factors leading to these disparities.


Assuntos
Calcâneo/lesões , Traumatismos do Pé/cirurgia , Fixação Interna de Fraturas/estatística & dados numéricos , Fraturas Fechadas/cirurgia , Disparidades em Assistência à Saúde/etnologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Estados Unidos
6.
J Environ Radioact ; 208-209: 106038, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31494388

RESUMO

Aerial Gamma-Ray Surveys (GRS) are ideal for tracking anthropogenic gamma radiation releases and transport. The interpretation of a GRS can be complicated by natural gamma-ray sources such as atmospheric radon, cosmic rays, geologic materials, and even the survey equipment itself. Some of these complicating factors can be accounted for or corrected by calibration or mathematic techniques. Real-time algorithms that attempt to enhance potential radiogenic anomalies over background are also in use. However, natural geology is a source of significant background gamma-ray production and neither mathematical corrections nor real-time algorithmic approaches directly account for geology and geochemistry. In this study, we advance techniques to predict geologic background exposure rates using rapid and practical methods which can be achieved in the field. In addition we generate models that focus specifically on highlighting radiogenic anomalies for emergency response or further investigation. Predictive models developed in this study were generally able to predict background with medians of ± 1.0 µR/h compared to measured data, and were also able to highlight anomalous areas even where radiation exposure rates were within the range of natural background.


Assuntos
Exposição à Radiação/estatística & dados numéricos , Monitoramento de Radiação , Tecnologia de Sensoriamento Remoto , Radiação de Fundo , Raios gama
7.
Astrobiology ; 18(12): 1543-1558, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30132684

RESUMO

Phosphate is an essential nutrient for life on Earth, present in adenosine triphosphate (ATP), deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and phospholipid membranes. Phosphorus does not have a significant volatile phase, and its release from minerals is therefore critical to its bioavailability. Organic ligands can enhance phosphate release from minerals relative to release in inorganic solutions, and phosphorus depletion in paleosols has consequently been used as a signature of the presence of ligands secreted by terrestrial organisms on early Earth. We performed batch dissolution experiments of the Mars-relevant phosphate minerals merrillite, whitlockite, chlorapatite, and fluorapatite in solutions containing organic compounds relevant to Mars. We also analyzed these phosphate minerals using the ChemCam laboratory instrument at Los Alamos, providing spectra of end-member phosphate phases that are likely present on the surface of Mars. Phosphate release rates from chlorapatite, whitlockite, and merrillite were enhanced by mellitic, oxalic, succinic, and acetic acids relative to inorganic controls by as much as >35 × . The effects of the organic compounds could be explained by the denticity of the ligand, the strength of the complex formed with calcium, and the solution saturation state. Merrillite, whitlockite, and chlorapatite dissolution rates were more strongly enhanced by acetic and succinic acids relative to inorganic controls (as much as >10 ×) than were fluorapatite dissolution rates (≲2 ×). These results suggest that depletion of phosphate in soils, rocks or sediments on Mars could be a sensitive indicator of the presence of organic compounds.


Assuntos
Apatitas/análise , Fosfatos de Cálcio/análise , Sedimentos Geológicos/química , Minerais/análise , Compostos Orgânicos/análise , Fosfatos/análise , Solo/química , Cálcio/análise , Concentração de Íons de Hidrogênio , Ligantes , Análise Espectral
8.
OTA Int ; 1(1): e001, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-33937639

RESUMO

BACKGROUND: Hispanics represent the largest minority group in the United States and are projected to represent 29% of the US population by 2060. Enrolling Hispanic patients in clinical outcome trials is critical to study a representative sample of the general population. Lack of translated and validated survey tools has been identified as a major barrier to enrolling Spanish speaking patients. The purpose of this validation study was to study the correlation between the Spanish translation of the American Academy of Orthopaedic Surgeons Foot and Ankle Outcomes questionnaire (AAOS-FAOQ) and the Spanish versions of the Foot Function Index (FFI) and the Foot Health Status Questionnaire (FHSQ) in Hispanics from Mexican lineage with traumatic foot and ankle injuries. METHODS: A cross-sectional validation study in 36 Hispanic patients from Mexican lineage with foot and ankle injuries was performed. The Hispanic version of the AAOS-FAOQ and the Spanish translations of the FAOQ, FHSQ, FFI, and the Short-Form 36 questionnaire (SF-36) were distributed among all patients. Subsequent statistical analysis correlating the Hispanic version of the AAOS-FAOQ to the FFI, FHSQ, and SF-36 was performed. Additional analysis on the Hispanic AAOS-FAOQ included test-retest reliability and internal consistency. RESULTS: The Hispanic AAOS-FAOQ Global Foot and Ankle subscale showed statistically significant (P < .05) correlations with 5 of 8 subscales of the FHSQ, the FFI, and the Physical Component Summary subscale of the SF-36. The AAOS-FAOQ Global Foot & Ankle Scale also demonstrated a test-retest reliability of 0.736 and a strong internal consistency. CONCLUSIONS: This study further validates AAOS-FAOQ in Mexican Hispanics by showing strong correlations with the validated Spanish versions of the FFI and FHSQ.

9.
Nat Commun ; 8(1): 1230, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-29089493

RESUMO

Clay mineral-bearing locations have been targeted for martian exploration as potentially habitable environments and as possible repositories for the preservation of organic matter. Although organic matter has been detected at Gale Crater, Mars, its concentrations are lower than expected from meteoritic and indigenous igneous and hydrothermal reduced carbon. We conducted synthesis experiments motivated by the hypothesis that some clay mineral formation may have occurred under oxidized conditions conducive to the destruction of organics. Previous work has suggested that anoxic and/or reducing conditions are needed to synthesize the Fe-rich clay mineral nontronite at low temperatures. In contrast, our experiments demonstrated the rapid formation of Fe-rich clay minerals of variable crystallinity from aqueous Fe3+ with small amounts of aqueous Mg2+. Our results suggest that Fe-rich clay minerals such as nontronite can form rapidly under oxidized conditions, which could help explain low concentrations of organics within some smectite-containing rocks or sediments on Mars.

10.
J Environ Radioact ; 171: 41-64, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28182978

RESUMO

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation environment is unknown. Two study areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.


Assuntos
Radiação de Fundo , Modelos Químicos , Monitoramento de Radiação , Nevada
11.
J Environ Radioact ; 165: 68-85, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27640123

RESUMO

This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.


Assuntos
Radiação de Fundo , Modelos Químicos , Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Arizona , Raios gama , Geologia , Mineração , Tório/análise , Urânio/análise
12.
Emerg Med J ; 33(1): 57-60, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25987594

RESUMO

OBJECTIVE: Social media (SoMe) are gaining increasing acceptance among, and use by, healthcare service deliverers and workers. UK Helicopter Emergency Medical Services (HEMS) use SoMe to deliver service information and to fundraise, among other purposes. This article examines UK HEMS use of SoMe between January and February 2014 to determine the extent of adoption and to highlight trends in use. METHODS: The database of the Association of Air Ambulances, crosschecked with UK Emergency Aviation, was used to identify flying, charitable UK HEMS. This search identified 28 UK HEMS, of which 24 services met the criteria for selection for review. Using information harvested from the public domain, we then systematically documented SoMe use by the services. RESULTS: SoMe use by UK HEMS is extensive but not uniform. All selected UK HEMS maintained websites with blogs, as well as Facebook, Twitter, Wikipedia and JustGiving profiles, with the majority of services using Ebay for Charity, LinkedIn and YouTube. Some HEMS also held a presence on Pinterest, Google+, Instagram and Flickr, with a minority of services maintaining their own Rich Site Summary (RSS) feed. CONCLUSIONS: The SoMe adopted, while varied, allowed for increased, and different forms of, information delivery by HEMS to the public, often in real time. Such use, though, risks breaching patient confidentiality and data protection requirements, especially when information is viewed cumulatively across platforms. There is an urgent need for the continued development of guidance in this unique setting to protect patients while UK HEMS promote and fundraise for their charitable activities.


Assuntos
Resgate Aéreo/estatística & dados numéricos , Competência Profissional , Mídias Sociais/estatística & dados numéricos , Resgate Aéreo/ética , Instituições de Caridade/ética , Instituições de Caridade/métodos , Confidencialidade , Obtenção de Fundos/ética , Obtenção de Fundos/métodos , Humanos , Segurança do Paciente , Mídias Sociais/ética , Mídias Sociais/legislação & jurisprudência , Mídias Sociais/tendências , Fatores de Tempo , Reino Unido
13.
Astrobiology ; 15(12): 1060-75, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26684505

RESUMO

UNLABELLED: Abundant evidence indicates that significant surface and near-surface liquid water has existed on Mars in the past. Evaluating the potential for habitable environments on Mars requires an understanding of the chemical and physical conditions that prevailed in such aqueous environments. Among the geological features that may hold evidence of past environmental conditions on Mars are weathering profiles, such as those in the phosphorus-rich Wishstone-class rocks in Gusev Crater. The weathering profiles in these rocks indicate that a Ca-phosphate mineral has been lost during past aqueous interactions. The high phosphorus content of these rocks and potential release of phosphorus during aqueous interactions also make them of astrobiological interest, as phosphorus is among the elements required for all known life. In this work, we used Mars mission data, laboratory-derived kinetic and thermodynamic data, and data from terrestrial analogues, including phosphorus-rich basalts from Idaho, to model a conceptualized Wishstone-class rock using the reactive transport code CrunchFlow. Modeling results most consistent with the weathering profiles in Wishstone-class rocks suggest a combination of chemical and physical erosion and past aqueous interactions with near-neutral waters. The modeling results also indicate that multiple Ca-phosphate minerals are likely in Wishstone-class rocks, consistent with observations of martian meteorites. These findings suggest that Gusev Crater experienced a near-neutral phosphate-bearing aqueous environment that may have been conducive to life on Mars in the past. KEY WORDS: Mars-Gusev Crater-Wishstone-Reactive transport modeling-CrunchFlow-Aqueous interactions-Neutral pH-Habitability.


Assuntos
Meio Ambiente Extraterreno/química , Sedimentos Geológicos/química , Marte , Fosfatos/química , Água/química , Exobiologia , Concentração de Íons de Hidrogênio , Minerais , Modelos Teóricos , Fósforo , Solubilidade , Tempo (Meteorologia)
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...