453 research outputs found

    Esophageal Stenting in the Setting of Malignancy

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    Esophageal cancer is often diagnosed at an advanced stage, with many patients found to have locoregional or metastatic disease at time of diagnosis. Because of this, cure may be unlikely, leading treatment efforts to focus more on symptom palliation and improving patient quality of life. The majority of patients with advanced disease suffer from some degree of dysphagia. Palliative efforts are therefore directed at relieving dysphagia, allowing patients to manage their oropharyngeal secretions, reduce aspiration risk, and maintain caloric intake orally. A variety of endoscopic treatment modalities have been utilized with these objectives in mind, with options determined by the location and size of the tumor, as well as the patient's expected prognosis. In this article, we review the use of endoscopically-placed stents for palliation in patients with advanced esophageal cancer. We discuss the history of stent use in such cases, as well as more recent developments in stent technology. We give an overview of some of the more commonly used stents in practice, discuss the technique of insertion, and survey the short- and long-term outcomes of stent placement

    Polarization Maintaining, Very-Large-Mode Area, Er Fiber Amplifier for High Energy Pulses at 1572.3 nm

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    We demonstrate the first polarization maintaining, very-large-mode-area Er-doped fiber amplifier with ~1000 square micron effective area. The amplifier is core pumped by a Raman fiber laser and is used to generate single frequency one microsecond pulses with pulse energy of 368 microJoules, M2 of 1.1, and polarization extinction greater than 20 dB. The amplifier operates at 1572.3 nm, a wavelength useful for trace atmospheric CO2 detection

    A dedicated electric oven for characterization of thermoresistive polymer nanocomposites

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    AbstractThe construction, characterization and control of an electric oven dedicated to the study of thermoresistive polymer nanocomposites is presented. The oven is designed with a heating plate capable of reaching 300°C with a resolution of 0.3°C and an area of uniform temperature of 3.8cm×2.5cm. The temperature is regulated by means of a discrete proportional–integral–derivative controller. A heat transfer model comprising three coupled non-linear differential equations is proposed to predict the thermal profiles of the oven during heating and cooling, which are experimentally verified. The oven is used for thermoresistive characterization of polymer nanocomposites manufactured from a polysulfone polymer and multiwall carbon nanotubes

    Temporal and spatiotemporal autocorrelation of daily concentrations of Alnus, Betula, and Corylus pollen in Poland

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    The aim of the study was to determine the characteristics of temporal and space–time autocorrelation of pollen counts of Alnus, Betula, and Corylus in the air of eight cities in Poland. Daily average pollen concentrations were monitored over 8 years (2001–2005 and 2009–2011) using Hirst-designed volumetric spore traps. The spatial and temporal coherence of data was investigated using the autocorrelation and cross-correlation functions. The calculation and mathematical modelling of 61 correlograms were performed for up to 25 days back. The study revealed an association between temporal variations in Alnus, Betula, and Corylus pollen counts in Poland and three main groups of factors such as: (1) air mass exchange after the passage of a single weather front (30–40 % of pollen count variation); (2) long-lasting factors (50–60 %); and (3) random factors, including diurnal variations and measurements errors (10 %). These results can help to improve the quality of forecasting models

    Synthesis and in vitro antiprotozoal activity of some 2- amino-4-phenyloxazole derivatives

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    Purpose: To prepare some 2-amino-4-(p-substituted phenyl)-oxazole derivatives and to evaluate their in vitro antiprotozoal activity against Giardia lamblia and Trichomonas vaginalis.Methods: The 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized by microwave (MW) irradiation of mixtures of p-substituted 2-bromoacetophenones and urea in dimethylformamide (DMF). All compounds were identified by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and lowand high-resolution mass spectrometry (HRMS). NMR assignments were made based on heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments. Each synthesized compound’s melting point was determined. Antiprotozoal activity against Giardia intestinalis and Trichomonas vaginalis was quantified using a rigorous and sensitive subculture method. The commercial drug, metronidazole, was used as positive control. The 50 % inhibitory concentration (IC50) of the antiprotozoal agents for each protozoa was determined.Results: Seven 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized. The most active compounds against G. lamblia was 2-amino-4-(p-benzoyloxyphenyl)-oxazole (3d) with an IC50 of 1.17 μM, while compound 3e (2-amino-4-(p-bromophenyl)-oxazole) showed the highest anti-trichomonal activity (IC50, 1.89 μM).Conclusion: The in vitro antigiardial activity of 2-amino-4-(p-benzoyloxyphenyl) oxazole was higher than that exhibited by metronidazole; however, it is necessary increase the number of synthetic derivatives in order to be able to determine their structure-activity relationship.Keywords: Antiprotozoal, 2-Amino-4-phenyl-oxazoles, Giardia lamblia, Trichomonas vaginali

    Oak pollen in the air of Poland in 2017

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    The aim of the study was to compare the pollen season of oak in the cities of Bialystok, Bydgoszcz, Cracow, Katowice, Piotrkow Trybunalski, Lublin, Olsztyn, Opole, Szczecin, Warsaw, Wroclaw and Zielona Gora in 2017. Measurements were performed by the volumetric method (Hirst type pollen sampler). Seasonal Pollen Index (SPI) was estimated as the sum of daily average pollen concentrations in the given season. Pollen season was defined as the period in which 98% of the annual total catch occurred. The pollen season of oak started first in Szczecin, on the 1st April, and lasted till the end of May. At the latest pollen season ended in Olsztyn on the 1st June. However, in the most of other cities the season lasted till the end of May. The differences of pollen seasons duration were considerables from 28 to 56 days. The highest, record airborne concentration of 342 pollen grains/m3 was noted in Warsaw on the 17th May. The maximum values of seasonal pollen count occurred between of 11th and 20th May. The highest oak pollen allergen hazard occurred in 2017 in Piotrkow Trybunalski, Lublin and Warsaw

    Alder pollen season in poland in 2018

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    Alder pollen grains constitute the important allergen sources in this respect in the Northern Hemisphere. The aim of the study was to investigate the concentration of alder (Alnus spp.) in Bialystok, Bydgoszcz, Cracow, Drawsko Pomorskie, Lublin, Olsztyn, Opole, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw and Zielona Gora in 2018. Measurements were performed by the volumetric method (Burkard and Lanzoni pollen samplers). Seasonal Pollen Index (SPI) was estimated as the annual sum of daily average pollen concentrations. The pollen season of alder in all Polish stations began on the 11th and 13th March and the high concentration persisted until the first days of April. The highest, record airborne concentration of 1068 pollen grains/m3 was noted in Lublin on the 13th March. The peak values of seasonal pollen count occurred between of 11th March and 4th April in all cities. In 2018 pollen concentration of alder was one of the lowest in all analysed cities

    Main technical-productive characteristics of meliponiculture in two locations of the municipality of Calkiní, Campeche

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    Objective: to identify the main technical-productive characteristics of two production systems (traditional and technified) dedicated to meliponiculture in two locations in the municipality of Calkiní, Campeche. Design/methodology/approach: From August to December 2021, applications of semi-structured interviews of 60 reagents were carried out to the meliponiculturists of Pucnanchen and Santa Cruz. Where by means of the snowball method the population of meliponiculturists was found. Results: A total of 43 colonies of bees of the species M. beecheii (39 hobones and 14 technified boxes) were found. The meliponiculturists interviewed are over 49 years old and have an average of 10.75 colonies per meliponary. Likewise, the modern meli-ponarios have replaced the roofing with huano, by the use of galvanized sheet and the hobones have been replaced by the use of technified boxes for the breeding of native bees. Limitations of the study/implications: this study describes the technical-productive characteristics of the two production systems used in meliponiculture (traditional and technical) in two locations in the municipality of Calkiní, Campeche. Findings/conclusions: there is a reduction in the number of people who practice meliponiculture, which is an activity that is still rooted in rural communities and that still retains importance from the economic, cultural and cultural point of view. Social. The uses of melipona honey in the health of people belonging to rural communities, is an activity that still persists, as well as the customs associated with the religious context.Objective: To identify the main technical-productive characteristics of two meliponiculture production systems—traditional and technical—in two locations of the municipality of Calkiní, Campeche. Design/Methodology/Approach: Semi-structured interviews of 60 items were applied to bee growers from Pucnanchen and Santa Cruz between August and December 2021. The population of meliponiculturists was established by using the snowball method. Results: We found a total of 43 bee colonies of the M. beecheii species (39 hobones and 14 technified boxes). The interviewed meliponiculturists are over 49 years old and have an average of 10.75 colonies per meliponary. In modern meliponaries, galvanized metal sheets have replaced huano (Sabal yapa) leaf roofing. Likewise, some hobones have been replaced by technified boxes to breed native bees. Study limitations/Implications: This study describes the technical-productive characteristics of the two production systems (traditional and technical) used in meliponiculture in two locations of the municipality of Calkiní, Campeche. Findings/Conclusions: There is a decline in the number of people practicing meliponiculture, an activity still rooted in rural communities and that retains its economic, cultural, and social importance. In rural communities, the use of melipona honey for health purposes persists, as well as the religious customs associated with this type of honey

    A prognostic model of all-cause mortality at 30 days in patients with cancer and COVID-19

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    Background: Patients with cancer are at higher risk of dying of COVID-19. Known risk factors for 30-day all-cause mortality (ACM-30) in patients with cancer are older age, sex, smoking status, performance status, obesity, and co-morbidities. We hypothesized that common clinical and laboratory parameters would be predictive of a higher risk of 30-day ACM, and that a machine learning approach (random forest) could produce high accuracy. Methods: In this multi-institutional COVID-19 and Cancer Consortium (CCC19) registry study, 12,661 patients enrolled between March 17, 2020 and December 31, 2021 were utilized to develop and validate a model of ACM-30. ACM-30 was defined as death from any cause within 30 days of COVID-19 diagnosis. Pre-specified variables were: age, sex, race, smoking status, ECOG performance status (PS), timing of cancer treatment relative to COVID19 diagnosis, severity of COVID19, type of cancer, and other laboratory measurements. Missing variables were imputed using random forest proximity. Random forest was utilized to model ACM-30. The area under the curve (AUC) was computed as a measure of predictive accuracy with out-of-bag prediction. One hundred bootstrapped samples were used to obtain the standard error of the AUC. Results: The median age at COVID-19 diagnosis was 65 years, 53% were female, 18% were Hispanic, and 16.7% were Black. Over half were never smokers and the median body mass index was 28.2. Random forest with under sampling selected 20 factors prognostic of ACM-30. The AUC was 88.9 (95% CI 88.5-89.2). Highly informative parameters included: COVID-19 severity at presentation, cancer status, age, troponin level, ECOG PS and body mass index. Conclusions: This prognostic model based on readily available clinical and laboratory values can be used to estimate individual survival probability within 30-days for COVID-19. In addition, this model can be used to select or classify patients with cancer and COVID-19 into risk groups based on validated cut points, for treatment selection, prophylaxis prioritization, and/or enrollment in clinical trials. Future work includes external validation using other large datasets of patients with COVID-19 and cancer
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