718 research outputs found

    Modeling Compressible Non-Newtonian Chicken Flow

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    This paper addresses a few modeling issues relevant for the basic theoretical understanding of the meat flow behavior in simple geometries. We model the meat mixture as a non-Newtonian compressible fluid. Focusing on conceptually easy-to-follow cases like flow in thin molds, or steady incompressible or compressible flow in straight pipes we derive explicit expressions for the velocity and pressure profiles. For the thin moldcase, we formulate a one-dimensional free-boundary problem able to capture the a priori unknown position of the moving meat-air interface. Special attention is payed on the derivation of the free boundary conditions

    Some biological aspects of Gammarus lacustris Sars, 1863 in Neur Lake Ardabeel province, Iran

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    A biological study was conducted to find out about reproduction and feeding of G. lacustris in Neur Lake from northwest mountains of Iran. Plankton diversity, hydro-chemical factors and substrate characteristic were recorded monthly. Findings showed that reproduction period of this species was short and limited to May and the mean brood size was 10.2 ± 5.3 eggs per female. The hydro-chemical analysis showed the eutrophic characteristic of Neur Lake in which the average of total organic matter was 3.7 ± 3.0 percent. The phyla representative Bacillariophyta, Chlorophyta and Cyanophyta were observed throughout the study and Chlorophyta was the dominant group. Three zooplankton phyla Rotatoria, Ciliophora and Copepoda were abundant respectively. Study on diet using gut content resulted in identification of 15 plankton genera with some resemblance to planktons of the lake

    Synthesis of biscoumarin derivatives by the reaction of aldehydes and 4-hydroxycoumarin using ruthenium (III) chloride hydrate as a versatile homogeneous catalyst

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    The one-pot domino Knoevenagel-type condensation/Michael reaction of aromatic, heteroaromatic and aliphatic aldehydes with 4-hydroxycoumarin in aqueous media in the presence of ruthenium salt as homogeneous catalyst was investigated. It was found that 5 mol% of RuCl3.nH2O catalyzes biscoumarin synthesis in high yields (70-95%) under optimised, mild, green and environmentally benign reaction conditions in short times (25-35min)

    Antioxidant capacity and fatty acid profile of <i>Centaurea kotschyi</i> (Boiss. & Heldr.) Hayek var. <i>persica</i> (Boiss.) Wagenitz from Turkey

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    The antioxidant capacity of the methanolic extract and the fatty acid composition of <i>C. kotschyi</i> var. <i>persica</i> were investigated. Six different chemical methods were used to determine the antioxidant capacity. The fatty acid composition was analyzed using gas chromatography. The IC50 value of the extract was determined as 37.09 μg/ml (in the DPPH assay). In the β-carotene/linoleic acid system, the extract exhibited 65.22% inhibition against linoleic acid oxidation. The amount of total phenolic content and total antioxidant capacity were detected as 36.52 mg gallic acid equivalent (GAE)/g and 74.93 mg ascorbic acid equivalent (AE)/g, respectively. The major fatty acid in the composition of <i>C. kotschyi</i> var. <i>persica</i> was found to be C 18:3 ω3 (α-linolenic acid) by GC analysis. The results presented here indicate that <i>C. kotschyi</i> var. <i>persica</i> possess strong antioxidant properties. Therefore, the species can be used as a natural additive in food, cosmetic and pharmaceutical industries.<br><br>La capacidad antioxidante de extractos metanólicos y composición de ácidos grasos de <i>C. kotschyi</i> var. <i>pérsica</i> fueron investigados. Seis métodos químicos diferentes fueron realizados para la determinación de la capacidad antioxidante. La composición de ácidos grasos fue analizada por cromatografía de gases. Los valores de IC50 de los extractos fueron 37.09 μg/ml (en el ensayo con DPPH). En el sistema β-carotene/ácido linoleico, el extracto mostró un 65.22% de inhibición frente a la oxidación del ácido linoleico. La cantidad total de contenido fenólico y capacidad antioxidante total fueron 36.52 mg equivalentes de ácido gallico (GAE)/g y 74.93 mg equivalentes de ácido ascórbico (AE)/g, respectivamente. El principal ácidos graso encontrado, por análisis de CG, en <i>C. kotschyi</i> var. <i>pérsica</i> fue el C 18:3 ω3 (ácido α-linolenico). Los resultados presentados aquí indican que <i>C. kotschyi</i> var. <i>pérsica</i> posee unas fuertes propiedades antioxidantes. Además, las especies pueden ser usadas como aditivos naturales en los alimentos, en cosmética y en industria farmacéutica

    Biomechanical comparison of the pullout properties of external skeletal fixation pins in the tibiae of intact and ovariectomised ewes.

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    The pin-bone interface is the least stable component of the external skeletal fixator. Concerns exist regarding the ability to obtain adequate implant purchase in poor quality bone. Consequently, reduced bone quality has been viewed as a contra-indication for the use of external skeletal fixators. The aim of this study was to investigate the holding power of two different fixator pin designs in bone from entire and ovariectomised sheep. Thirty-two aged ewes were divided into two groups. Group 1 were controls, and Group 2 were ovariectomised (OVX). The ewes were sacrificed 12 months post-ovariectomy and five pairs of tibiae were harvested from each group. The holding power of cortical and cancellous fixator pins was assessed at five standardised locations on each tibia. An increase in mean cortical thickness was noted in the OVX group. The holding power of cancellous fixator pins was superior to that of cortical pins, irrespective of whether or not ovariectomy had been performed. Cancellous pins had an increased holding power in post ovariectomy bone compared to control bone. Cortical pin performance was not affected by ovariectomy. There was a lack of correlation between the incidence of insertional fractures of the far cortex and implant holding power. The results raise questions over the effectiveness of ovariectomy in establishing osteopaenic bone suitable for assessing implant performance, hence further investigations are warranted

    Simulation of crystalline silicon photovoltaic cells for wearable applications

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    Advancements in the semiconductor industry have enabled wearable devices to be used for a wide range of applications, including personalised healthcare. Novel energy harvesting technologies are therefore necessary to ensure that these devices can be used without interruption. Crystalline silicon photovoltaic cells provide high energy density to electronic loads. However, the optimization of these cells is a complex task since the optical performance is coupled to the surroundings, and the electrical performance is influenced by the intrinsic PV characteristics and parasitic losses.Without doubt, accurate simulation tools can provide the necessary insight to PV cell performance before device fabrication. However, the majority of these tools require expensive licensing fees. Thus, the aim of this article is to review the range of non-commercial PV simulation tools that can be used for wearable applications. We provide a detailed procedure for device modelling and we compare the performance of these tools with previously published experimental data, as well as commercial software. According to our findings, non-commercial 3D simulation tools such as PC3D provide accurate results, with only a relative error of ≈2.2% in Jsc after setting off the difference in geometrical modelling due to the software limit

    The Effects of Cornus mas Hydro-Methanolic Extract on Cisplatin-Induced Nephrotoxicity in Rats

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    Background: Cisplatin (Cis) is a chemotherapeutic agent and nephrotoxicity is a serious adverse effect of the drug. This study investigated the protective effects of Cornus mas fruit hydro-methanolic extract (CME) on cisplatin-induced nephrotoxicity in a rat model. Methods: Forty Wistar rats were divided into the control group, CME group, CME 300 + Cis group, CME 700 + Cis group, and Cis group. After the intervention samples were taken for biochemical and histopathological analysis. Results: The CME analysis showed considerable total antioxidant and total phenol contents. The blood serum urea and creatinine increased (p 0.05). The renal MDA levels of the Cis and CME 300 + Cis groups decreased significantly in comparison to the control and the CME groups (p < 0.01 and p < 0.05, respectively). In the histopathological examination, mild to severe degeneration was observed in the Cis group. Despite the presence of mild degeneration, they were less severe in the Cis + CME groups, and maintained a better morphology when compared to the Cis group (p < 0.01). Conclusion: The results showed renoprotective effects of CME against Cis-induced nephrotoxicity in rats

    Using theatre in education in a traditional lecture oriented medical curriculum

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    <p>Abstract</p> <p>Background</p> <p>Lectures supported by theatrical performance may enhance learning and be an attractive alternative to traditional lectures. This study describes our experience with using theatre in education for medical students since 2001.</p> <p>Methods</p> <p>The volunteer students, coached by experienced students, were given a two-week preparation period to write and prepare different dramatized headache scenarios during three supervised meetings. A theatrical performance was followed by a student presentation about history taking and clinical findings in diagnosing headache. Finally, a group discussion led by students dealt with issues raised in the performance. The evaluation of the theatre in education lecture "A Primary Care Approach to Headache" was based on feedback from students.</p> <p>Results</p> <p>More than 90% of 43 responding students fully agreed with the statement "Theatrical performance made it easier to understand the topic". More than 90% disagreed with the statements "Lecture halls were not appropriate for this kind of interaction" and "Students as teachers were not appropriate". Open-ended questions showed that the lesson was thought of as fun, good and useful by most students. The headache questions in the final exam showed results that were similar to average exam results for other questions.</p> <p>Conclusion</p> <p>Using theatrical performance in medical education was appreciated by most students and may facilitate learning and enhance empathy and team work communication skills.</p

    Near-IR and optical radial velocities of the active M-dwarf star Gl 388 (AD Leo) with SPIRou at CFHT and SOPHIE at OHP

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    Context: The search for extrasolar planets around the nearest M-dwarfs is a crucial step towards identifying the nearest Earth-like planets. One of the main challenges in this search is that M-dwarfs can be magnetically active and stellar activity can produce radial velocity (RV) signals that could mimic those of a planet. Aims: We aim to investigate whether the 2.2 day period observed in optical RVs of the nearby active M-dwarf star Gl 388 (AD Leo) is due to stellar activity or to a planet which co-rotates with the star as suggested in the past. Methods: We obtained quasi-simultaneous optical RVs of Gl 388 from 2019 to 2021 with SOPHIE (R\sim75k) at the OHP in France, and near-IR RV and Stokes V measurements with SPIRou at the CFHT (R\sim70k). Results: The SOPHIE RV time-series displays a periodic signal with 2.23±\pm0.01 days period and 23.6±\pm0.5 m/s amplitude, which is consistent with previous HARPS observations obtained in 2005-2006. The SPIRou RV time-series is flat at 5 m/s rms and displays no periodic signals. RV signals of amplitude higher than 5.3 m/s at a period of 2.23 days can be excluded with a confidence level higher than 99%. Using the modulation of the longitudinal magnetic field (Bl) measured with SPIRou, we derive a stellar rotation period of 2.2305±\pm0.0016 days. Conclusions: SPIRou RV measurements provide solid evidence that the periodic variability of the optical RVs of Gl 388 is due to stellar activity rather than to a co-rotating planet. The magnetic activity nature of the optical RV signal is further confirmed by the modulation of Bl with the same period. The SPIRou campaign on Gl 388 demonstrates the power of near-IR RV to confirm or infirm planet candidates discovered in the optical around active stars. SPIRou observations reiterate how effective spectropolarimetry is at determining the stellar rotation period.Comment: 25 pages, 23 figures, Accepted by Astronomy and Astrophysic
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