290 research outputs found

    On interaction between freely moving bodies and fluid in a channel flow

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    The interaction between free fast-moving bodies (or particles) and the fluid surrounding them is studied, motivated by applications in different branches of industry, biomedicine, the environment and science such as flying droplets, ice growth, dust, impacts, food grains, sport, complexity and storms. New inviscid-based modelling and results on the behaviour of two interacting bodies inside a channel flow are described. This is followed by discussion of the more-bodies extension with a view to treating arrays of bodies in a rational manner. Significant dependences on initial conditions and on the comparative body masses and moments of inertia are found for the occurrence of body-body impacts as opposed to wall-body impacts and for the associated impact times

    Photosynthetic responses of Amygdalus arabica Olivier and Atriplex canescens (Pursh) Nutt. to drought stress under field conditions

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    The central Anatolian region of Turkey is exposed to increasing temperatures and severe drought stress. Due to aridity and desertification brought about by global warming, climate change and overutilization, plant species in these regions are under the risk of extinction. Thus, plant species have to adapt to these harsh environmental conditions of extremely high temperatures and low precipitation. In this study, gas exchange and water potentials of the Arabian almond tree Amygdalus arabica Olivier (C3-photosynthesis) and four-winged saltbush Atriplex canescens (Pursh) Nutt. (C4-photosynthesis), two drought-tolerant woody species planted previously in an effort to reduce desertification at Karapınar, Konya, and Central Anatolian Region, were periodically measured from May until September under field conditions. Net photosynthesis and transpiration rates, mid-day water potential and water use efficiency were determined throughout the vegetation period in 2015. Maximum net photosynthetic rates were 12.4 Ī¼mol mā€“2 sā€“1 in the Arabian almond tree and 29.7 Ī¼mol mā€“2 sā€“1 in four-winged saltbush, measured in July and September, respectively. Also, the highest transpiration rates were 4.8 mmol mā€“2 sā€“1 in the Arabian almond tree and 7.1 mmol mā€“2 sā€“1 in four-winged saltbush. Maximum water use efficiency values were measured in June in both species, which made up 5.7 and 7.7 mmol CO2 molā€“1 H2O for the Arabian almond tree and four-winged saltbush, respectively. Lowest midday water potentials for both species were recorded in August. The results indicate that both species have the ability to tolerate drought stress in the region, though due to its C4 nature of photosynthesis, the four-winged saltbush might overcome those stresses more efficiently than the Arabian almond tree in arid and barren areas

    Tulathromycin disturbs blood oxidative and coagulation status

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    The aim of this study was to determine the effect of tulathromycin on serum oxidative status and coagulation factors in rabbits. Tulathromycin was administered to eight rabbits, and blood samples were obtained 0, 1, 5, 10 and 15 days after treatment. Indicators of serum oxidative status (malondialdehyde, nitric oxide, superoxide dismutase, retinol and -carotene) and coagulation values (antithrombin III, fibrinogen) were measured after tulathromycin treatment. In addition, routine serum biochemical values (creatine kinase-MB, lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transferase, creatinine, blood urea nitrogen, cholesterol, triglyceride, high density lipoprotein, amylase, total protein, albumin, glucose and calcium), haemacell counts (white and red blood cells) and arterial blood gas parameters (packed cell volume, hemoglobin, pH, partial pressure of carbon dioxide, partial pressure of oxygen, actual bicarbonate, standard bicarbonate, total carbon dioxide, base excess in vivo, base excess in vitro, oxygen saturation, sodium and potassium) were also determined. Tulathromycin increased (P < 0.05) the levels of malondialdehyde, nitric oxide and superoxide dismutase activity, and decreased (P < 0.05) the level of antithrombin III. In conclusion, tulathromycin may cause oxidative damage and coagulation disorders during the treatment period.Key words: Tulathromycin, oxidative damage, coagulation disorder

    Fall detection using single-tree complex wavelet transform

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    The goal of Ambient Assisted Living (AAL) research is to improve the quality of life of the elderly and handicapped people and help them maintain an independent lifestyle with the use of sensors, signal processing and telecommunications infrastructure. Unusual human activity detection such as fall detection has important applications. In this paper, a fall detection algorithm for a low cost AAL system using vibration and passive infrared (PIR) sensors is proposed. The single-tree complex wavelet transform (ST-CWT) is used for feature extraction from vibration sensor signal. The proposed feature extraction scheme is compared to discrete Fourier transform and mel-frequency cepstrum coefficients based feature extraction methods. Vibration signal features are classified into "fall" and "ordinary activity" classes using Euclidean distance, Mahalanobis distance, and support vector machine (SVM) classifiers, and they are compared to each other. The PIR sensor is used for the detection of a moving person in a region of interest. The proposed system works in real-time on a standard personal computer. Ā© 2012 Elsevier B.V. All rights reserved

    Outcome of Fenestrated Endovascular Aneurysm Repair in Octogenarians:A Retrospective Multicentre Analysis

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    Objective: An ageing population leads to more age related diseases, such as complex abdominal aortic aneurysms (AAA). Patients with complex AAAs and multiple comorbidities benefit from fenestrated endovascular aneurysm repair (FEVAR), but for the elderly this benefit is not completely clear. Methods: Between 2001 and 2016 all patients treated for complex AAA by FEVAR at two tertiary referral centres were screened for inclusion. Group 1 consisted of patients aged 80 years and older and group 2 of patients younger than 80 years of age. The groups were compared for peri-operative outcome, as well as patient and re-intervention free survival, and target vessel patency during follow up. Results: Group 1 consisted of 42 patients (median age 82 years; interquartile range [IQR] 81ā€“83 years) and group 2 of 230 patients (median age 72 years; IQR 67ā€“77 years). No differences were seen in pre-operative comorbidities, except for age and renal function. Renal function was 61.4 mL/min/1.73 m2 vs.74.5 mL/min/1.73 m2 (p < .01). No differences were seen between procedures, except for a slightly longer operation time in group two. Median follow up was 26 and 32 months, respectively. No difference was seen between the groups for estimated cumulative overall survival (p = .08) at one, three, and five years, being 95%, 58%, and 42% for group 1, and 88%, 75%, and 61% for group 2, respectively. There was no difference seen between groups for the estimated cumulative re-intervention free survival (p = .95) at one, three, and five years, being 84%, 84%, and 84% in group 1, respectively, and 88%, 84%, and 82% in group 2, respectively. Ultimately, no difference was seen between groups for the estimated cumulative target vessel patency (p = .56) at one, three, and five years, being 100%, 100%, and 90% for group 1, and 96%, 93% and 92% for group 2, respectively. Conclusion: Age itself is not a reason to withhold FEVAR in the elderly, and choice of treatment should be based on the patient's comorbidities and preferences

    Distal posterior tibial artery perforator flaps for the management of calcaneal and Achilles tendon injuries in diabetic and non-diabetic patients

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    Management of Achilles tendon and heel area defects is a common challenge for the reconstructive surgeon due to the lack of soft tissue availability in that region. In this article, we present our experience in covering these defects by using the distal perforator propeller flaps based on the posterior tibial artery. Perforator flaps are based on cutaneous, small diameter vessels that originate from a main pedicle and perforate the fascia or muscle to reach the skin. Their development has followed the understanding of the blood supply from a source artery to the skin. Six patients (five males and one female) underwent reconstruction by using the posterior tibial artery distal perforator flap for covering defects in the distal Achilles tendon region in patients with and without diabetes mellitus. Postoperative complications included a hypertrophic scar formation in one patient, partial marginal flap necrosis in another patient, and a wound infection in a third patient. All wounds were eventually healed by the last postoperative visit. In conclusion, perforator flaps based on the distal posterior tibial artery may be a reliable option for the coverage of small to moderate size defects of the Achilles tendon and heel area regions

    A rare variant of the superficial ulnar artery, and its clinical implications: a case report

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    The superficial ulnar artery is a rare variation of the upper limb arterial system that arises from the brachial or axillary artery and runs superficial to the muscles arising from the medial epicondyle [1-3]. The incidence is about 0.7 to 7% [1,4,5]. In our routine dissections we found a superficial ulnar artery, which crossed the cubital fossa superficial to the bicipital aponeurosis making it highly vulnerable to intra-arterial injection. This is a rare variation that every medical and nursing staff member should know about
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