The Motion of a Point Vortex in Multiply Connected Polygonal Domains

We study the motion of a single point vortex in simply and multiply connected polygonal domains. In case of multiply connected domains, the polygonal obstacles can be viewed as the cross-sections of 3D polygonal cylinders. First, we utilize conformal mappings to transfer the polygonal domains onto circular domains. Then, we employ the Schottky-Klein prime function to compute the Hamiltonian governing the point vortex motion in circular domains. We compare between the topological structures of the contour lines of the Hamiltonian in symmetric and asymmetric domains. Special attention is paid to the interaction of point vortex trajectories with the polygonal obstacles. In this context, we discuss the effect of symmetry breaking, and obstacle location and shape on the behavior of vortex motion

Eradication of Banana Viruses from Naturally Infected Banana Plants 2. Production of Certified Banana Plants and Virus Tested

Abstract: For production certified banana plants and virus tested from naturally infected plants, RT-PCR was done to detect BMV and BBTV in shoot tips of banana cv. Williams. Meristem tip (apical dome) culture has been frequently used to eliminate BMV and BBTV. It was found that the survival plants were 20 and 15% while the virus free plants were 70 and 75% respectively. Two kind of therapeutic in vitro were applied. The micropropagated shoots were exposed to 36, 38 and 40°C for 30 days. The besttemperature that gave virus-free plants was 36°C (100% for BBTV and 60% for BMV). On the other hand dry heat treatment of 40°C at one weekis useful in curing the infected rhizomes effectively.Two antiviral compounds,ribavirin and salicylic acid at concentration 10 mg/L medium enhanced growth differentiation of the propagative meristem, while decreasing of virus free plants percentage. Onthe other hand 30 mg/Lof two antiviraldecrease the development of shoot micropropagated plantlets and had a deleterious effect on the regeneration and growth of the propagated shoots but increase of virus free plantlets, 90 with ribavirin and 93 and 90 with salicylic acid for BBTV and BMV respectively. Randomly amplified polymorphic DNA (RAPD) fingerprints was used to analyzesomaclonal variations in tissue culture-derived banana plants.RAPD analysis showed geneticvariations of the analyzed plants (10 regenerates). The genetic variations in approximately 4% were detected in 6 subculture and mother plants

Cell free preparations of probiotics exerted antibacterial and antibiofilm activities against multidrug resistant E. coli

The sharp increase in antibiotic resistance imposes a global threat to human health and the discovery of effective antimicrobial alternatives is needed. The use of probiotics to combat bacterial pathogens has gained a rising interest. Pathogenic Escherichia coli is causative of multiple clinical syndromes such as diarrheal diseases, meningitis and urinary tract infections. In this work, we evaluated the efficacy of probiotics to control multidrug-resistant E. coli and reduce their ability to form biofilms. Six E. coli resistant to at least five antibiotics (Ceftazidime, Ampicillin, Clarithromycin, Amoxicillin + Clavulanic Acid and Ceftriaxone) were isolated in this work. Preparations of cell-free spent media (CFSM) of six probiotics belonging to the genus Bifidobacterium and Lactobacillus which were grown in Man-Rogosa-Sharpe (MRS) broth exhibited strong antibacterial activity (inhibition zones of 11.77–23.10 mm) against all E. coli isolates. Two E. coli isolates, namely E. coli WW1 and IC2, which were most resistant to all antibiotics were subjected to antibiofilm experiments. Interestingly, the CFSM of MRS fermented by all probiotics resulted in inhibition of biofilm formation while B. longum caused highest inhibition (57.94%) in case of E. coli IC2 biofilms and L. plantarum was responsible for 64.57% reduction of E. coli WW1 biofilms. On the other hand, CFSM of skim milk fermented by L. helveticus and L. rhamnosus exhibited a slight inhibitory activity against IC2 isolate (inhibition percentage of 31.52 and 17. 68, respectively) while WW1 isolate biofilms was reduced by CFSM of milk fermented by B. longum and L. helveticus (70.81 and 69.49 reduction percentage, respectively). These results support the effective use of probiotics as antimicrobial alternatives and to eradicate biofilms formed by multidrug-resistant E. coli. Keywords: Probiotics, Lactobacillus, Bifidobacterium, Multidrug resistance, E. col

Improved antibacterial efficacy of bacteriophage-cosmetic formulation for treatment of Staphylococcus aureus in vitro

Currently phages are used as alternative antibiotics for treating pathogenic bacteria causing skin disease. However, the efficacy of pure preparations of phage is greatly reduced due to its short longevity on surface of skin. supplemented cosmetic phages [0.5% phage conc./cosmetic] significantly increased phage longevity on skin surface. The phages were isolated by the single plaque assay from the infected skin showing edema and erythema symptoms. The isolated phages had plaques with 3–5 mm diameters and a distinct translucent spreading halo. The morphological phage particles were cubic nucleocapsid with 65–75 nm across with short contractile tails. The supplemented cosmetic phages reduced the bacterial growth to 95.45%, compared with free phages and non-supplemented cosmetic 86.1% and 77% respectively. The phage containing cosmetic was applied for disease treatment and increased the phage longevity from 24 to 100 h and preserved initial phage population. This work indicated the enhanced antibacterial efficacy of fortifying specific bacteriophage in cosmetics to be a promising formulation for efficient treatment of skin diseases

The inflation hedging capacity of Islamic and conventional equities

Purpose: This study analyzes the inflation hedging of Islamic and conventional equities by employing 26 indices for the period ranging from January 1996 till August 2018. The authors investigate the decoupling hypothesis for Islamic versus conventional equities across various investment horizons. Design/methodology/approach: The authors employ a vector autoregressive framework coupled with bootstrapping procedure to compute inflation hedging measures. The hedging measures employed account for the inflation hedging capacity in terms of hedging effectiveness as well as the cost of hedging (efficiency). The authors account for various investment horizons ranging from one month to ten years. Findings: Although, the authors do not find consistent evidence for the decoupling hypothesis of Islamic and conventional equities in terms of their inflation hedging capacity. However, the authors document that certain Islamic equity indices can be employed to effectively hedge against the risk of inflation. Originality/value: The main contribution of this study is that the existing literature on the comparative performance of Islamic versus conventional equities against inflation risk is sparse. The purpose of this study is to analyze the inflation hedging attributes of Islamic versus conventional equities, that is, whether Islamic equities render better real returns than their conventional counterparts. It will contribute to the growing literature on the comparison between Islamic and conventional equities by documenting the real return attributes of these two, apparently different, assets. A further contribution is that in order to account for the different investment horizons for different types of investors, this study will quantify the real return attributes of Islamic and conventional equities for short-, medium- and long-term investors. © 2019, Emerald Publishing Limited

Transformation of the Political System of Saudi Arabia: Regional Dimension

The Kingdom of Saudi Arabia is considered one of the pivotal countries in the region and the international community due to its political and economic weight. The importance of this role comes with the Saudi weight in the Arab Gulf and the importance of the Gulf for the Kingdom’s security in general, as well as being at the forefront of the countries bordering the Gulf in terms of the volume of output and oil reserves. Since the year 2010, changes in the regional environment of the Kingdom of Saudi Arabia have pushed towards reconsidering some of the problems and challenges to which its policy was exposed, and it has moved towards searching for what it deems best to enhance its security and stability in the region. However, this role is faced with internal, economic, political, social, regional and international challenges, The need to adapt in the formation of its positions on regional issues, in line with the changes that occurred in the structure of the Arab regional system and the decline in the position of some regional actors, which led to the multiplicity of Saudi regional proposals to formulate its strategic directions to confront the state of imbalance in the region, in addition to that. Its keenness to fulfill its obligations towards its regional allies, as is the case in Yemen, Saudi Arabia has benefited from being an effective regional state, but its effectiveness must be negatively affected by what is happening on or around its territory. And that future expectations do not serve this role much

Systemic thromboembolic complications after laparoscopic splenectomy for idiopathic thrombocytopenic purpura in comparison to open surgery in the absence of anticoagulant prophylaxis

BACKGROUND: Idiopathic thrombocytopenic purpura (ITP) in adults has a chronic course and may necessitate splenectomy. The current study was undertaken to study the systemic thromboembolic complications of laparoscopic splenectomy (Ls) versus open splenectomy (Os) in patients with ITP at two large referral hospitals. PATIENTS AND METHODS: We conducted a retrospective analysis of 49 patients who underwent splenectomy (21 LS and 28 OS) for primary/relapsing refractory ITP between June 1995 and November 2004. Clinically and/or radiologically confirmed deep venous thrombosis (DVT) and/or pulmonary embolism (PE) were assessed within 2 weeks before and after splenectomy. None had prophylactic anticoagulants immediately after surgery. Follow up of those who developed complications continued for at least 2 additional years to assess for contributing factors that may have been masked at the time of occurrence. RESULTS: Two (9.5%) Ls group had acute PE within 5 days of LS and their platelet count reached 500×103/μL within 4 days and 1000×103/μL within 7 days after surgery. Three conversions to OS occurred; none had VTE. DVT occurred in 3 patients (10.7%) in the Os group; none were life threatening. There were no deaths. CONCLUSION: Life-threatening venous thromboembolic events are serious complications after LS and OS for ITP patients if prophylactic anticoagulants are not administered. Patients at risk are those who both have an exponential rise of the platelet count, although factors other than the platelet count may be contributing in OS. Postsplenectomy, ITP should be considered as a thrombophilic condition and studies of additional measures to prevent such events are warranted