237 research outputs found
High-efficiency non-thermal plasma synthesis of imine macrocycles
Macrocycles are candidates for wide-ranging applications, yet their synthesis can be low-yielding, poorly reproducible, and resource-intensive, limiting their use. Here, we explore the use of Non-Thermal Plasma (NTP) as an efficient method for the synthesis of imine macrocycles at the gram scale. NTP-mediated macrocyclisations consistently achieved high yields of up to 97% in reduced reaction times compared to the standard non-plasma method, and were successfully carried out with a range of different aldehyde substrates. Control experiments were performed to explore the origin of the observed improvements. The results indicate that NTP methods could be advantageous for macrocycle synthesis, particularly for substrates that are sensitive to elevated temperature, and other materials formed via imine condensation
Family dairy farms in the Podlasie province, Poland: farm typology according to farming system
The aim of this paper is to establish a farm typology according to the dairy farming systems in the western part of the Podlasie province. Data of 39 variables was collected by a survey to owners of 123 family farms. A two-stage multivariate analysis was conducted in order to determine farm typology. Three principal components were detected, explaining 80.4% of the total variance. The cluster analysis identified five groups of farms. In two groups the cow productivity is the biggest in the area. A third group contains the smallest and lowest cow productivity farms, with high proportion of non-agricultural activities. One of the two remaining groups has better soil quality and medium cow productivity. The other group has low or medium soil quality but cow productivity is higher than in the fourth group. The SWOT analysis shows different weaknesses and strengths for different groups, as well as those common to a larger number of groups. Weaknesses are related to small farm size, large number of workers, low or medium soil quality and low or medium level of technology. Strengths are related to a large share of fodder crops, low livestock density, diversification of agrarian activities and acceptable cow productivity. On the other hand, general opportunities are linked to the EU-CAP evolution and to the presence of cooperatives in the region, whereas general threats derive from a hypothetic increase of feed prices and quantity of milk produced in the EU, which could lead to a fall in milk prices.El objetivo de este trabajo es establecer tipologías de sistemas lecheros en el oeste de Podlasia (Polonia). Se analizaron 39 variables a partir de encuestas realizadas a propietarios de 123 explotaciones. Tras el análisis multivariante en dos etapas (factorial y cluster) se encontraron tres componentes principales que explican el 80,4% de la varianza total y se obtuvieron cinco grupos de explotaciones. En dos de los grupos la productividad de las vacas es la mayor de la zona. Un tercer grupo tiene las granjas más pequeñas y menos productivas, con una mayor proporción de actividades no agrarias. El cuarto tiene los suelos de mejor calidad y una productividad de las vacas media y el quinto tiene suelos de calidad media o baja pero una productividad de las vacas superior. En general, las debilidades están relacionadas con una escasa dimensión de las granjas, un elevado número de trabajadores, una baja o media calidad de los suelos y un bajo o mediano nivel de tecnología. Las fortalezas están relacionadas con la abundancia de cultivos forrajeros, una carga ganadera baja, una aceptable diversificación agraria y una aceptable productividad de las vacas. Las principales oportunidades están ligadas a la evolución de la PAC de la UE y a la presencia de cooperativas para la comercialización de la leche. Las principales amenazas derivan de los posibles incrementos de precios de los alimentos para el ganado y de leche producida en la UE, que puede conducir a una caída de los precios de venta de la leche
One-Year Results of Photorefractive Keratectomy for Myopia and Compound Myopic Astigmatism with 210 nm Wavelength All Solid-State Laser for Refractive Surgery
Background: To examine the 12-month clinical and refractive outcomes of PRK performed with a UV all-solid-state laser. Methods: The study included healthy patients with myopia and/or compound myopic astigmatism enrolled for refractive surgery and treated with PRK using a 210 nm wavelength, 2 kHz repetition rate, UV all-solid-state laser (LaserSoft, Katana Technologies GmbH, Kleinmachnow, Germany). All subjects were examined at baseline and after 1, 3, 6, and 12 months after the treatment with a slit lamp, refraction, visual acuity assessment (logMAR chart), tonometry, ophthalmoscopy, and corneal tomography with a Scheimpflug camera. The outcome measures considered were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, central corneal thickness, and transparency. The efficacy, safety, predictability, and stability were determined. Results: The study included 34 eyes of 19 patients. The mean UDVA changed from 1.20 & PLUSMN; 0.43 to -0.05 & PLUSMN; 0.10 logMAR at 12 months, and the mean CDVA changed from -0.03 & PLUSMN; 0.06 to -0.06 & PLUSMN; 0.09 logMAR, respectively. The mean spherical equivalent (SE) changed from -4.90 & PLUSMN; 2.12 D to -0.01 & PLUSMN; 0.40 D and was within & PLUSMN;0.50 D of the intended correction in 91% of eyes and within & PLUSMN;1.00 D in 97% of eyes at 12 months. No eyes lost lines of visual acuity, and 64% of eyes gained one or more lines. Conclusions: PRK with the 210 nm wavelength, 2 kHz repetition rate, all-solid-state laser LaserSoft system proved to have good visual, refractive, and clinical outcomes after the follow-up at 12 months. The emerging gas-free, solid-state technology might be considered a valid alternative for the gas operating lasers for corneal refractive surgery
Influence of soil contaminated with cadmium on cell death in the digestive epithelium of soil centipede Lithobius forficatus (Myriapoda, Chilopoda)
Cadmium is a heavy metal that is treated as an environmental pollutant (air, water, soil). In order to understand the potential
effects of cadmium in soil and soil invertebrates, it is important to describe all alterations which appear at different levels in
organisms. The main aim of this study was to investigate, analyze and describe the alterations caused by cadmium short- and
long-term intoxication at different levels in the organisms: from tissues to cells and organelles. In addition, the activation of cell
deathmechanisms that take part in homeostasismaintenance according to cadmium has been studied. Therefore, as the species
for this project, a terrestrial and well-known widespread European species – the centipede Lithobius forficatus (Myriapoda,
Chilopoda, Lithobiomorpha) – was chosen. This omnivorous species lives under upper layers of soil, under stones, litter, rocks,
and leaves, and it is also commonly found in human habitats. The animals were divided into three groups: C – the control
group, animals cultured in a horticultural soil; Cd1 – animals cultured in a horticultural soil supplemented with 80 mg/kg (dry
weight) of CdCl2, 12 days – short-term exposure; Cd2 – animals cultured in a horticultural soil supplemented with 80 mg/kg
(dry weight) of CdCl2, 45 days – long-term exposure. The midgut was isolated from each specimen and it was prepared for
analysis using some histological, histochemical and immunohistochemical methods. Our studies showed that short-term
intoxication causes intensification of autophagy and digestion of reserve material, while long-term exposure to this heavy
metal causes activation of cell death processes together with inhibition of autophagy connected with the lack of reserve material.
Additionally, we can infer that autophagy and cell death are nutrient deprivation-induced processes. Finally, we can conclude
that short- and long-term exposure of soil centipede to cadmium affects different mechanisms and processes of cell death
Severe Corneal Morphological Alterations after Excimer Laser Surface Ablation for a High Astigmatism
We report long-term alterations of anterior corneal stroma after excimer laser surface ablation for a high astigmatism. The patient claimed progressive visual loss in his right eye (RE) during the last 3 years after bilateral laser-assisted subepithelial keratectomy (LASEK) surgery. His examination comprised visual acuity (UDVA and CDVA), slit-lamp examination, corneal topography and tomography, AS-OCT, and confocal microscopy. The UDVA was 0.1 in his RE and 1.0 in the left eye. The CDVA in the RE was 0.8. The slit-lamp examination showed a stromal lesion in the inferior paracentral corneal zone, with multiple vertical tissue bridges and severe thinning. Corneal topography and tomography showed central flattening with inferior steepening and severe alteration in elevation maps. AS-OCT showed void areas in the anterior stroma with thinning of the underlying tissue, and confocal images were not specific. In this case, progressive corneal steepening and thinning that manifest topographically as inferior ectasia occurred in correspondence to the singular stromal alterations after LASEK
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