•A mechanism-based model is developed to simulate visco-hyperelastic material response.•Material nonlinearity is simulated by geometric nonlinearity of the linkage mechanism.•The mechanism also ...displays relaxation, hysteresis and dynamic stiffness responses.•The mechanical behavior of the proposed mechanism model matches test results well.
In this study, basic linear lumped elements such as springs and dashpots are used in nested linkage mechanisms in order to simulate the mechanical behavior of visco-hyperelastic materials. The proposed mechanism model containing two nested linkages can show initial softening followed by hardening response under quasi-static loading, which is commonly displayed by hyperelastic materials. Hence, material nonlinearity is simulated by geometric nonlinearity of the linkage mechanism. The mechanism also displays relaxation, hysteresis, and dynamic stiffness responses of viscoelastic materials with the help of dashpot elements. Visco-hyperelastic material behavior is closely approximated by the proposed mechanism model for the four different test scenarios, i.e., quasi-static loading, ramp-and-hold loading, hysteresis, and dynamic stiffness tests. It is shown that nonlinearity and frequency dependency of visco-hyperelastic materials is successfully captured.
In the present study, morphological and anatomical structures of cypsela – 12
Cirsium
Miller (Carduoideae, Asteraceae) taxa belonging to two sections (sect.
Cirsium
and sect.
Cephalonoplos
) were ...investigated in detail with using stereomicroscope and light microscope. The taxa were evaluated comparatively in the aspect of carpological variations and their anatomies were presented in here for the first time. Morphological features including size, shape and colour of cypselae were examined. From anatomical observations, anatomical structures of pericarp, as well as the structure of testa were described. Cypselae colours differ from light brown to stramineous, sometimes with blackish striations. Their shapes change from oblong to oblanceolate, rarely obovate. The largest cypselae are present in
C. echinus
(1.59±0.03 mm × 4.68±0.07 mm) and the smallest ones are found in
C. subinerme
(1.20±0.02 mm × 2.97±0.05 mm). The pericarp is characterised by almost parenchymatous cells, while the testa is composed of lignified sclerenchymatous cell lines and crushed cells group. Secretory structure in testa bundle was evaluated. Results obtained from this study were compared with the present data in literature. Overall, morphological and anatomical characteristics of cypselae provide useful taxonomic markers in their classifications of the studied taxa of
Cirsium
but not distinctive for their sectional levels.
Moringa spp. seeds has recently been characterized with regard to its seed oil potential. Mature seeds of Moringa plant contains 38–54% edible oil. The oil of Moringa spp. seeds were found to contain ...high level of unsaturated fatty acids. The dominant saturated fatty acids were palmitic, lauric acid, stearic, linoleic and linolenic acid. Oleic acid was the most abundant of the unsaturated fatty acids found in Moringa oleifera seed oil. The major sterol components of the M. oleifera seed oil were β-sitosterol, campesterol, stigmasterol and ∆5, avenasterol. The major sterol components of the Moringa oil were α-,Ɣ- and δ-tocopherols. Moringa oleifera is an important food commondity which has had enormous attention as the natural nutrition of the tropics. The extracts from Moringa spp. could be an effective source of natural antimicrobials with versatile potential applications. Traditionally, almost all parts of Moringa flower, fruits and roots are edible, and have long been consumed as vegetable.
•Moringa oleifera Lam belongs to a single genus family Moringaceae.•The leaves, fruits, flowers and immature pods of this tree are edible.•The plant seeds contain hypotensive activity, strong antioxidant activity.•Moringa, commonly called Drumstick or Horse Radish Tree, is a fast growing tree and is•propagated quite easily.
Recent data from several reports indicate that free radicals are involved in the biochemical mechanisms underlying neuropsychiatric disorders in human. The results of several reports suggest that ...lower antioxidant defences against lipid peroxidation exist in patients with depression and that there is a therapeutic benefit from antioxidant supplementation in unstable manic-depressive patients. We investigated the antioxidant enzyme status and the indices of oxidative stress and lipid peroxidation end products in erythrocytes from patients with affective disorder. For this purpose, we measured superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, as well as malondialdehyde (MDA) and nitric oxide (NO) levels in patients with affective disorders (n=30) in both pre- and post-treatment periods, and in a control group (n=21). CAT activities were significantly decreased in both pre-, and post-treatment periods in patients compared to the control group. GSH-Px activity in the pre-treatment period in the patients was significantly lower than both post-treatment patient and control groups. MDA levels were increased in both pre-, and post-treatment patient groups compared to the control group. NO level was lower in the pre-treatment patient group than in the control group. There were statistically significant correlations between SOD and MDA, and SOD and NO in the pre-treatment patient and control groups. Because the overall study sample was small, and the post-treatment patient group was even smaller, it can tentatively be suggested that the antioxidant system is impaired during a mood episode in patients with affective disorders, normalizing at the end of the episode.
▶ Page and modified Page models fit well for the oven drying of red bell-pepper. ▶ Sun and microwave oven drying led to higher
L*,
a*,
b* values than oven drying. ▶ The antioxidant activity of dried ...red bell-pepper is higher than the fresh crop.
The sun, oven (50 and 70
°C) and microwave oven (210 and 700
W) drying behaviors of red bell-pepper slices were investigated. Effects of these drying methods in terms of colour indices and antioxidant activity of pepper slices were also studied. “Midilli and Küçük” model exhibited high coefficient of determination (
R
2) values for all the drying methods used in the assay, ranging between 0.994–0.999, while “Page” and “Modified Page” models fit better for oven drying at 70
°C. The calculated effective diffusivity (
D
eff
) values (m
2/s) of pepper slices for the drying processes ranged between 0.31 and 87.39
×
10
−9. Sun dried and followed by microwave oven (700
W) dried samples revealed the highest
L
*,
a
* and
b
* colour values than the other dried samples. Microwave oven dried (210
W) and oven dried (50
°C) samples exhibited the lowest TEAC and DPPH radical scavenging activities among the dried samples.
Rosemary leaves (
Rosmarinus officinalis L., Lamiaceae) were dried by using sun, oven (50
°C) and microwave oven (700
W, 2450
MHz) drying methods. Microwave oven drying shortened the drying time more ...than 99% when compared to the sun and oven drying methods. K, Ca, Na, Mg and P were the most abundant elements in the rosemary samples. The mineral content of oven dried rosemary leaves was higher than that of the sun and microwave dried samples. The logarithmic and Midilli and Küçük models were shown to give a good fit to the sun and oven drying. The Page, Modified Page and Midilli and Küçük models have shown a better fit to the experimental microwave oven drying data of rosemary leaves. Microwave oven drying revealed optimum colour values. Oven drying resulted in a considerable decrease in the colour quality of the rosemary leaves.
•Gestation accelarates brain tumor growth but parousity reduces risk of gliomas.•Progesterone suppresses glioma growth with high dose and prolonged exposure.•MPA (medroxyprogesterone) blocked growth ...and invasion of human glioblastoma cells.•MPA also blocked growth of intracranially implanted C6 astrocytoma growth in vivo.
Glial tumor growth may accelerate during gestation, but epidemiological studies consistently demonstrated that parousity reduces life long risk of glial tumors. Pregnancy may also accelerate growth of medulloblastoma and meningioma, but parousity does not confer protection against these tumors. We were the first to show that medroxyprogesterone acetate (MPA) reduces rat C6 glioma growth in vitro. Now we aimed to determine the effects of MPA on human brain cancers (particularly glioblastoma) in vitro and C6 glioma in vivo.
We evaluated the effects of MPA on: i) monolayer growth of human U87 and U251 glioblastoma, ii) 3D-spheroid growth and invasion of C6 rat glioma and human U251 glioma, iii) interactions with PI3-Kinase inhibitors and coxsackie-adenovirus receptor (CAR) in modifying 3D-spheroid invasion of glioma.
MPA at low doses (3.25–13 μM) insignificantly stimulated and at high doses (above 52 μM) strongly suppressed the growth of human U87 and U251 cells in vitro. MPA also binds to glucocorticoid receptors similar to dexamethasone (Dex) and unexpectedly, PI3-Kinase inhibitors at low doses suppressed anti-invasive efficacies of MPA and Dex. MPA exerted higher invasion-inhibitory effects on CAR-expressing human glioma cells. Lastly, MPA suppressed growth of C6 glioma implanted into rat brain.
Progesterone analogues deserve to be studied in future experimental models of high grade glial brain tumors.
Novel stable ultra-thin phases of europium oxide are investigated by means of state-of-the-art first principles calculations. Total energy calculations show that single layers of EuO2 and Eu(OH)2 can ...be stabilized in an octahedrally coordinated (1T) atomic structure. However, phonon calculations reveal that although both structures are energetically feasible, only the 1T-EuO2 phase has dynamical stability. The phonon spectrum of 1T-EuO2 displays three Raman active modes; a non-degenerate out-of-plane A1g mode at 353.5 cm-1 and two doubly-degenerate in-plane Eg modes at 304.3cm-1. Furthermore, magnetic ground state and electronic band dispersion calculations show that the single layer EuO2 is a metal with net magnetic moment of 5μB per unitcell resulting in a half-metallic ferrimagnetic behavior. Moreover, robustness of the half-metallic ferrimagnetic characteristics of EuO2 is confirmed by the application of electric field and charging. Single layer 1T-EuO2, with its stable ultra-thin structure and half-metallic ferrimagnetic feature, is a promising novel material for nanoscale electronic and spintronic applications.
We compared the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging procedures. Sixty children were randomly distributed ...into two groups: The dexmedetomidine (D) group received 1 microg/kg initial dose followed by continuous infusion of 0.5 microg.kg(-1).h(-1) and a propofol group (P) received 3 mg/kg initial dose followed by a continuous infusion of 100 microg.kg(-1).min(-1). Inadequate sedation was defined as difficulty in completing the procedure because of the child's movement during magnetic resonance imaging. Mean arterial pressure (MAP), heart rate, peripheral oxygen saturation, and respiratory rate (RR) were recorded during the study. The onset of sedation, recovery, and discharge time were significantly shorter in group P than in group D. MAP, heart rate, and RR decreased during sedation from the baseline values in both groups. MAP and RR were significantly lower in group P than in group D during sedation. Desaturation was observed in four children of group P. Dexmedetomidine and propofol provided adequate sedation in most of the children. We conclude that although propofol provided faster anesthetic induction and recovery times, it caused hypotension and desaturation. Thus, dexmedetomidine could be an alternative reliable sedative drug to propofol in selected patients.
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