Functional and genetic evidence that nucleoside transport is highly conserved in Leishmania species: Implications for pyrimidine-based chemotherapy
Journal ArticleLeishmania pyrimidine salvage is replete with opportunities for therapeutic intervention with enzyme inhibitors or antimetabolites. Their uptake into cells depends upon specific transporters; therefore it is essential to establish whether various Leishmania species possess similar pyrimidine transporters capable of drug uptake. Here, we report a comprehensive characterization of pyrimidine transport in L. major and L. mexicana. In both species, two transporters for uridine/adenosine were detected, one of which also transported uracil and the antimetabolites 5-fluoruracil (5-FU) and 5F,2'deoxyuridine (5F,2'dUrd), and was designated uridine-uracil transporter 1 (UUT1); the other transporter mediated uptake of adenosine, uridine, 5F,2'dUrd and thymidine and was designated Nucleoside Transporter 1 (NT1). To verify the reported L. donovani model of two NT1-like genes encoding uridine/adenosine transporters, and an NT2 gene encoding an inosine transporter, we cloned the corresponding L. major and L. mexicana genes, expressing each in T. brucei. Consistent with the L. donovani reports, the NT1-like genes of either species mediated the adenosine-sensitive uptake of [3H]-uridine but not of [3H]-inosine. Conversely, the NT2-like genes mediated uptake of [3H]-inosine but not [3H]-uridine. Among pyrimidine antimetabolites tested, 5-FU and 5F,2'dUrd were the most effective antileishmanials; resistance to both analogs was induced in L. major and L. mexicana. In each case it was found that the resistant cells had lost the transport capacity for the inducing drug. Metabolomics analysis found that the mechanism of action of 5-FU and 5F-2'dUrd was similar in both Leishmania species, with major changes in deoxynucleotide metabolism. We conclude that the pyrimidine salvage system is highly conserved in Leishmania species - essential information for the development of pyrimidine-based chemotherapy.
Juma Ahmed Mohamed Ali, (08-2017), Netherlands: International journal for parasitology. Drugs and drug resistance, 2 (7), 206-226
On the Solution of the Eigenvalue Assignment Problem for Discrete-Time Systems
Journal ArticleTe output feedback eigenvalue assignment problem for discrete-time systems is considered. Te problem is formulated frst as
an unconstrained minimization problem, where a three-term nonlinear conjugate gradient method is proposed to fnd a local
solution. In addition, a cut to the objective function is included, yielding an inequality constrained minimization problem, where a
logarithmic barrier method is proposed for fnding the local solution. Te conjugate gradient method is further extended to tackle
the eigenvalue assignment problem for the two cases of decentralized control systems and control systems with time delay. Te
performance of the methods is illustrated through various test examples.
Fatma Farag Said Omar, El-Sayed M. E. Mostafa, Abdallah W. Aboutahoun,, (08-2017), Journal of Applied Mathematics: تم أختياره, 2017 (1), 1-13
Bagged textural and color features for melanoma skin cancer detection in dermoscopic and standard images.
Journal ArticleAbstract—Early detection of malignant melanoma skin cancer is crucial for treating the disease and saving lives. Many computerized techniques have been reported in the literature to diagnose and classify the disease with satisfactory skin cancer detection performance. However, reducing the false detection rate is still challenging and preoccupying because false positives trigger the alarm and require intervention by an expert pathologist for further examination and screening. In this paper, an automatic skin cancer diagno- sis system that combines different textural and color features is proposed. New textural and color features are used in a bag-of-features approach for efficient and accurate detection. We particularly claim that the Histogram of Gradients (HG) and the Histogram of Lines (HL) are more suitable for the analysis and clas- sification of dermoscopic and standard skin images than the conventional Histogram of Oriented Gradient (HOG) and the Histogram of Oriented Lines (HOL), respectively. The HG and HL are bagged separately us- ing a codebook for each and then combined with other bagged color vector angles and Zernike moments to exploit the color information. The overall system has been assessed through intensive experiments using different classifiers on a dermoscopic image dataset and another standard dataset. Experimental results have shown the superiority of the proposed system over state-of-the-art techniques.
Naser Alfed, Fouad Khelifi, (08-2017), Elsevier: Expert Systems With Applications, Elsevier, 90 (90), 101-110
Tradeoff in Optimistic Concurrency Control Algorithms for Centralized Database Systems
Journal ArticleOptimistic concurrency control is widely studied in the literature due to the properties of non-blocking and deadlock free execution especially in the domain of real-time systems. In this paper we review the substantial research of optimistic concurrency control protocols. We characterize them into four categories and explore their properties. Then we investigate the general concepts and properties related to Optimistic concurrency control Finally, we demonstrate a comparison table between the varieties of these
protocols.
Tarik Idbeaa, Tariq Khalifa, Kamal M. Solaiman, (07-2017), Univer: University of Bulletin, 19 (3), 59-86
Doxycycline induces SLT2 phosphorylation in Candida glabrata
Journal ArticleThe tetracycline promoter (tet) has been manipulated in several systems as an inducible regulator of gene expression. In this study the effect of doxycycline on C. glabrata viability has been examined in water and according to CLSI standard method. In addition, flow cytometry analysis was performed to detect SLT2 protein activation by sub-inhibitory concentrations of doxycycline. Our findings show that 100 µg/ml of doxycycline is the maximum tolerated dosage in media; however, C. glabrata was sensitive to 40-50µg/ml in water. 50 µg/ml of doxycycline induced SLT2p phosphorylation and our results support the idea of involvement of doxycycline in alteration of C. glabrata oxidative status. These results should be considered when the tet promoter system is used in yeast molecular studies
Hala Saied Farhat Almshawit, Ian Macreadie, (07-2017), international journal: International Journal of Clinical & Medical Microbiology, 2 (2), 122-126
Hybrid technique for robust image watermarking using discrete time fourier transform
Conference paperThe current paper proposes a novel scheme for non-blind watermarking of images, making use of discrete wavelet transform (DWT), discrete time Fourier transform (DTFT), as well as singular value decomposition, or SVD. During the process of embedding, 1-level DWT is used to decompose the host image into its various frequency sub-bands. After this, the high-frequency sub band receives an application of DTFT. This is followed then by SVD, after which the watermark becomes embedded into the now-transformed host image's singular matrix. Then, the inverses of 1-level DWT, DTFT and SVD are applied in order to obtain a watermarked final image. This paper evaluates the performance of the proposed method of watermarking against a number of attacks, including sharpening, salt and pepper noise, AWGN, gamma correction, histogram equalisation, flipping and cropping. Results obtained during experiments have found that the scheme as proposed does provide high levels of robustness and imperceptibility against various signal processing attacks.
Omar Moftah Ibrahim Abodena, Erbug Celebi, Mary Agoyi, (05-2017), 2017 25th IEEE Signal Processing and Communications Applications Conference: IEEE, 1-4
Logistic Growth with a Slowly Varying Holling Type II Harvesting Term
Journal ArticleThe Holling type II harvesting term has the property that it is small for small population values, but grows monotonically with population growth, eventually saturating, at a constant value for very large populations. We consider here a population evolving according to a logistic rate, but harvested (predated) subject to a Holling type II harvesting term that varies slowly with time, possibly due to slow environmental variation. Application of a multitiming method gives us an approximation to the population at any time in two cases- survival to a slowly varying limit, and extinguishment to zero. The situation where there is a transition from survival to extinction is also analyzed, using a matched expansions approach. A uniformly valid approximate expression for the population, valid for all times is obtained. These results are shown to agree well with the results of numerical calculations.
Majda Ashor Mohammad Idlango, John .J. Shepherd, (02-2017), Communications in Nonlinear Science and Numerical Simulation: ELSEVIER, 49 (1), 1-7
The Impact of Water and Some Salt Solutions on Some Properties of Hydrophilic Acrylamide Copolymeric Hydrogels
Journal ArticleAbstract-A series of polyelectrolyte hydrogels ranging from 92-98wt% were synthesized by copolymerization of acrylamide,
AAM with 2-acrylamido-2-methyl propane sulphonic acid, AMPS using 0.001g APS as initiator in the presence of 30wt% H2O
and 1.0wt% ethylene glycol dimethacrylate,EDMA as cross-linking agent. The final copolymers was obtained in the form of
glassy and transparent roads at room temperature, these roads were soaked in water for two days to remove unreacted
monomers. The swelling behavior of the hydrogels was studied in distilled water and salt solutions of 1.5 mol/l each of NaCl
and KCl. The Swelling in water shows decreasing values of q, LE, Ø1, EWC% and increasing polymer volume fraction, Ø2 by
increasing acrylamide, due to increasing hydrophobicity and decreasing the hydrophilicity. The swelling in salt solutions
shows a decreasing in the values of ESSNa%, WCNa%, SCNa%, ESSK%, WCK% and SCK% by increasing acrylamid
monomer in the feed due to increasing the hydrophobicity and decreasing the ionized ionic groups (SO3H). The increasing
values of ESSNa%, WCNa% and SCNa% compared with the values of ESSK%, WCK% and SCK% respectively, is due to
the higher charge density of sodium ion than that of potassium ion.
Shhoob Mohamed imhmed Elahmir, Abdurhman A.Abuabdalla Khalifa1, (01-2017), ابريطانيا: MAYFEB Journal of Materials Science, 1 (1), 7-16
Small-seeded Hakea species tolerate cotyledon loss better than large-seeded congeners
Journal ArticleSix Hakea species varying greatly in seed size were selected for cotyledon damage experiments. The
growth of seedlings with cotyledons partially or completely removed was monitored over 90 days. All
seedlings perished by the fifth week when both cotyledons were removed irrespective of seed size.
Partial removal of cotyledons caused a significant delay in the emergence of the first leaf, and reduction
in root and shoot growth of the large-seeded species. The growth of seedlings of small-seeded species
was less impacted by cotyledon damage. The rate of survival, root and shoot lengths and dry biomass
of the seedlings were determined after 90 days. When seedlings were treated with balanced nutrient
solutions following removal of the cotyledons, survival was 95–98%, but 0% when supplied with
nutrient solutions lacking N or P or with water only. The addition of a balanced nutrient solution failed
to restore complete growth of any species, but the rate of root elongation for the small-seeded species
was maintained. Cotyledons provide nutrients to support early growth of Hakea seedlings, but other
physiological roles for the cotyledons are also implicated. In conclusion, small-seeded Hakea species can
tolerate cotyledons loss better than large-seeded species.
Shhoob Mohamed imhmed Elahmir, Byron B. Lamont, Tianhua He, (01-2017), استراليا: Scientific Reports, 7 (1), 1-9
Efficient Vitrification for Cryopreservation
Journal ArticleAbstract:
Germplasm (Oocyte and embryo) and ovarian tissue cryopreservation have become routine procedure in human in vitro fertilization and embryo transfer. Human oocyte and embryo cryopreservation field has been much progress during its fourth decade history. Two basic strategies have ruled the mammalian germplasm cryopreservation field: the traditional slow freezing technique also referred as conventional slow freezing or controlled slow freezing which started in the 1970s, and followed by vitrification technique developed in the late 1980s, In the slow freezing protocol, the embryo is placed in a hypertonic solution and slowly cooled using a programmable freezer to sub-zero temperatures, and then plunged into liquid nitrogen, whereas vitrification technique can be performed by using high cooling rates and high concentration of cryoprotectants. In recent years vitrification technique is a common method for cryopreservation of oocytes and embryos in comparable to slow freezing method. Vitrification appears to be associated with a significantly higher post-thawing survival rate, higher implantation rate and more pregnancies than slow freezing. Vitrification protocol simplifies the cryopreservation process without physical damage to embryos and oocytes and decreases the chilling injuries of germplasm as it passes through a very low temperature very rapidly. Although germplasm cryopreservation has decreased the number of fresh embryo transfers and maximized the effectiveness of the in vitro fertilization cycle, further prospective trials are necessary to confirm that vitrification is a superior technique to slow freezing method. The purpose of the present mini-review is to highlight oocyte and embryo cryopreservation technique in general, with comparing the different laboratory methods in particular slow freezing (vs) vitrification and successful implantation after transfer.
Ramadan A. Alosta, (01-2017), مجلة القلم: مجلة القلم - جامعة طرابلس الأهلية, 5 (5), 1-11