Effective squirmer models for self-phoretic chemically active spherical colloids

Various aspects of self-motility of chemically active colloids in Newtonian fluids can be captured by simple models for their chemical activity plus a phoretic slip hydrodynamic boundary condition on their surface. For particles of simple shapes (e.g., spheres) -- as employed in many experimental studies -- which move at very low Reynolds numbers in an unbounded fluid, such models of chemically active particles effectively map onto the well studied so-called hydrodynamic squirmers [S. Michelin and E. Lauga, J. Fluid Mech. \textbf{747}, 572 (2014)]. Accordingly, intuitively appealing analogies of "pusher/puller/neutral" squirmers arise naturally. Within the framework of self-diffusiophoresis we illustrate the above mentioned mapping and the corresponding flows in an unbounded fluid for a number of choices of the activity function (i.e., the spatial distribution and the type of chemical reactions across the surface of the particle). We use the central collision of two active particles as a simple, paradigmatic case for demonstrating that in the presence of other particles or boundaries the behavior of chemically active colloids may be \textit{qualitatively} different, even in the far field, from the one exhibited by the corresponding "effective squirmer", obtained from the mapping in an unbounded fluid. This emphasizes that understanding the collective behavior and the dynamics under geometrical confinement of chemically active particles necessarily requires to explicitly account for the dependence of the hydrodynamic interactions on the distribution of chemical species resulting from the activity of the particles.Comment: 26 pages, 11 figure

A Novel Nanowire Metal Converter for Improvement the Efficiency of the Gas-filled Radiation Detectors

Metal nanowires, due to their special physical properties and also high surface to volume ratio, can have considerable applications in designing and development of novel nano devices. For the radiation shielding, higher absorption coefficient of nano structures in comparison to bulk ones is an advantage. In gas detectors, designing a proper converter with higher efficiency which absorbs higher energy of gamma and X-rays and convert it to free electrons is one of the major requirements. Since the nano wires have higher surface to volume ratio in comparison to the bulk ones, so it is expected that with the same thickness, the generated electrons have higher chance to escape from the surface. In this work, the random Copper nanowires with diameter of 40 nm are deposited on very thin glass slide. This nano structure with thickness of 30 μm is tested with X-rays energy between 12 to 22 keV. The results clearly show that this nano structure for the energy of 20 keV can release electrons three times more than the bulk ones. This novel nanoconverter with higher quantum efficiency can have many applications in high energy physics, medical imaging, and astronomy

An intelligent capacity management system for interface converter in AC-DC hybrid microgrids

An interface converter (IC) is used in an AC-DC hybrid microgrid (HMG) and its main tasks are frequency regulation in the AC side, adjusting the DC voltage, and controlling the power flow between AC/DC sides based on the droop control method. The IC should be capable of providing ancillary services such as reactive power supply and compensation of unbalanced and harmonic components in the AC side. However, the use of the IC to provide ancillary services occupies its capacity, which may interfere with the main tasks of the IC. In addition, it is shown in this paper that in unbalanced conditions, the effective power capacity of the IC is reduced by considering the current limit of the converter. In this case, the converter may not be able to perform the main task and provide all the necessary ancillary services at the same time, otherwise, it may be exposed to an overcurrent condition. Therefore, an efficient strategy is needed to manage the IC converter capacity to facilitate optimal use of the entire IC capacity even in unbalanced conditions. Given this challenge, this paper proposes an intelligent strategy for managing the IC capacity, which prioritizes the realization of the main task and the provision of ancillary services. The proposed strategy is evaluated, and its effectiveness is proven by simulation results in Matlab/Simulink

Chemical, microbial and sensory changes of silver carp (Hypophthalmichthys molitrix) fish treated with black cumin (Nigella sativa L.) extract during storage at refrigerator

The changes in chemical, microbial and quality sensory of fillets for silver carp fish treated with black cumin extract during refrigerated storage were investigated. The fish were divided into two groups. First group was dipped in black cumin extract with concentration of 1% and received the highest score in sensory evaluation. Then the fishes were wrapped in polyethylene package. The second group, as the control samples, were wrapped in polyethylene package after dipping in distilled water. All treatments were stored at refrigerator temperature (1±4°C). The microbial tests including total viable count, psychrotrophic count and chemical tests including peroxide index, thiobarbituric acid, free fatty acid value and total volatile basic nitrogen, with sensory evaluation, were done at 4°C over a period of 15 days. The results showed that the black cumin extract delayed lipid oxidation and protein analyses significantly in treated fishes. Psycrotrophic bacteria and total viable count of samples being treated with black cumin extract were maintained lower than the proposed acceptable limit (7 log cfu/g). In comparison to the control samples, microbial spoilage significantly decreased in treated samples. Furthermore, according to sensory analysis, the treatment with black cumin extract led to high quality during storage.The findings indicated that black cumin exerts had strong antioxidant and antibacterial impacts on silver carp fish, such that the shelf life of fillets being treated with black cumin were 2.5 times more than that of control samples during storage in refrigerator

The Effect of Stevia Rebaudiana on Serum Omentin and Visfatin Level in STZ-Induced Diabetic Rats

Recently the role of adipocytokines in relationship to incidence of diabetes has been demonstrated. One of the medicinal plants that are used in the treatment of diabetes is stevia. This study investigates the effect of stevia on serum omentin and visfatin levels as novel adipocytokines in diabetic induced rats to find potential mechanisms for the anti hyperglycemic effect of stevia. Forty male wistar rats weighing 180–250 g were induced with diabetes by intraperitoneal injection of streptozotocin (STZ). The animals were divided into 5 groups of 8. Rats in group 1 (non-diabetic control) and group 2 (diabetic control) were treated with distilled water, and the rats in the treated groups, group 3 (T250), group 4 (T500), and group 5 (T750) were treated with stevia, gavaged every day at 9 a.m. in doses of 250, 500, and 750 mg/kg, respectively. At the end of the study significant reductions in fasting blood sugar (FBS), the homeostasis model assessment insulin resistance (HOMA-IR), triglyceride (TG), alkaline phosphatase (ALP), and Omentin level were found in groups 3 and 4 in comparison with group 2. Pancreatic histopathology slides demonstrated that stevia extract did not induce any increase in the number of β-cells. The conclusion is that prescription of stevia in the doses of 250 and 500 mg/kg/d decreases the omentin level indirectly via activating insulin sensitivity and lowering blood glucose in STZ-induced diabetic rats. KEYWORDS. Diabetes, omentin, stevia, visfati

Comparison of the pregnancy outcomes between the medical and surgical treatments in tubal ectopi pregnancy

Background: Various treatments have been proposed to treat ectopic pregnancy, but their impact on future pregnancies is still the subject of controversy. Objective: The aim of this study is to compare the medical and surgical treatment methods and their impact on the subsequent fertility results and complications in women with a history of ectopic pregnancy. Materials and Methods: In this analytical, cross-sectional study, 370 women with the history of ectopic pregnancy, (treared with single dose of methotrexate or salpingectomy by laparotomy), that referred to Al-Zahra Hospital, Rasht, Guilan between 2009 to 2013 were enrolled. 147 women responded to the phone call. The age, the number of women that needed to drug for pregnancy, fertility rate and the fertility outcomes were studied. Result: 147 women responded to the call and between them, 114 women tried to get pregnant again after the ectopic pregnancy treatment. They were agreed to the participate in the study. The mean age of the patients was 28.56±5.63 yr. The fertility rates in the medical and the surgical groups were 56.6 and 47.61, respectively (p=0.141). There were no significant differences in the poor consequences of pregnancy among the two groups; ectopic pregnancy (p=0.605), miscarriage (p=0.605), and prematuredelivery (p=0.648). 15.1 in the medicinal group and two patients 12.5 in the surgical group had received fertility treatment in order to get pregnant (p=0.135). There was no significant difference in two groups. Conclusion: It seems that surgical treatment depending on the underlying variables of each patient, can be used such as medical treatment, without worrying about its effect on fertility. © 2018, Research and Clinical Center for Infertitlity. All rights reserved

Pollen-pistil compatibility relationships in some Iranian almond (Prunus dulcis, Batch) genotypes as revealed by PCR analysis

The identification of pollen-pistil compatibility relationships among almond cultivars and genotypes is very important for breeders and growers. In the present study, PCR based technique was used to identify S-alleles in 10 late blooming almond genotypes. In total, 19 alleles were amplified by five primer pairs in the studied genotypes. The size of bands ranged between 480 - 2000 bp. Seven S-alleles were amplified using AS1II/AMYC5R primer pair, whereas each of the Alsc11/AMYC5R, Pru-C2/Pru-C4R, Pru-C2/Pru-C5R and Pru-C2/Pru-C6R primer pairs amplified nine different S-alleles. Based on S-allele patterns, all of the studied genotypes were identified as self-incompatible. However, some of the genotypes had only one similar S-allele, all of the genotypes could be used in establishment of commercial orchards based on their blooming times