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Abstract Background Let-7 microRNAs (miRNAs) may contribute to neurodegeneration, including Alzheimer's disease (AD), but, they were not investigated in Streptozotocin (STZ)-induced AD. Letrozole increases the expression of Let-7 in cell lines, with conflicting evidence regarding its effects on memory. This study examined Let-7 miRNAs in STZ-induced AD, their correlation with memory and hyperphosphorylated Tau (p-Tau) and the effects of Letrozole on them. Methods Seven groups of adult Sprague Dawley rats were used: Negative control, Letrozole, Letrozole Vehicle, STZ (with AD induced by intracerebroventricular injection of STZ in artificial cerebrospinal fluid (aCSF)), CSF Control, STZ + Letrozole (STZ-L), and CSF + Letrozole Vehicle. Alternation percentage in T-maze was used as a measure of working memory. Let-7a, b and e and p-Tau levels in the hippocampus were estimated using quantitative real-time reverse transcription–polymerase chain reaction (qRT–PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Results Significant decreases in alternation percentage and increase in p-Tau concentration were found in the STZ, Letrozole and STZ-L groups. Expression levels of all studied microRNAs were significantly elevated in the Letrozole and the STZ-L groups, with no difference between the two, suggesting that this elevation might be linked to Letrozole administration. Negative correlations were found between alternation percentage and the levels of all studied microRNAs, while positive ones were found between p-Tau concentration and the levels of studied microRNAs. Conclusions This study shows changes in the expression of Let-7a, b and e miRNAs in association with Letrozole administration, and correlations between the expression of the studied Let-7 miRNAs and both the status of working memory and the hippocampal p-Tau levels. These findings might support the theory suggesting that Letrozole aggravates pre-existing lesions. They also add to the possibility of Let-7’s neurotoxicity.

Egypt plays an important role in the consuming markets for tires all over the world. There is an urgent need to get rid of them in an economic and environmental way since it is considered as a harmful waste if burnt. The World trend is directed towards the improvement of new techniques to insert the rubber into useful products to maximize the benefit of recycling. This research deals with the expansion of novel techniques for rubber powder recycling for various purposes in a robust construction. Recycled rubber particles (RRP) are mixed with ordinary Portland cement (OPC) using various water to binder ratio (W/B) at 0.3 and 0.4. The Fourier transform – infrared (FT-IR) spectra is measured for RRP. The compressive strength (C.S) is investigated for the rubberized cement pastes at 1, 3, 7, 14 and 28 days. The results aimed to enhance the compressive strength of rubberized cement pastes through improving the bonding strength between RRP and OPC by using fine particles of RRP. Maintaining the compressive strength in the highest levels with different RRP percentages in addition to the vibrational damping property of RRP gives rubberized cement pastes the advantage to replace ordinary concrete in most construction applications.

The organic treatment of the abstract of the Arabic character (contemporary vision)Yara Mustafa Abu-wally EL-FakharanyAssistant Teaching, Advertising DepartmentHigher Institute of Applied ArtsAbstractThe Arabic character is an artistic creativity, with its philosophy, organic movements, inspirations and special elements. It has the ability to respond and assist the visual artist to create a unique architectural style, according to visual systems aesthetic, emanating from the subjective form of the character, where the characters can be part of the composition of the painting (readable), or It is not related to the linguistic content (non-readable), that is, the characters are moving bodies and shapes with organic self-emotional, complementary just the art work .At the beginning of the twentieth century, when abstract art spread , the Arabic character appeared. It began to grow in a movement characterized by diversity and fertility, in which some of the visual artists inspire from the forms of Arabic characters to create their work, and reach a new organic form,such us Hamad Abd Allah, Saeed Akl, and others, since the beginning of the sixties of the twentieth century in the Arab world, they often resemble the human body with the types of Arabic characters, such us, the eyebrows like letter(ن ), and the flexibility of woman's body like letter (أ). In this regard, the Arabic letter was used as a form factor to construct the composition in the work of art in a purely organic manner, where the human bodies were treated with Arabic characters in an unreadable manner, undeclared for the shape of the letter, and the distance from its engineering structure and structural laws known by Ibn Mokala in his book, But has been used character specifications to suit the specifications of the human body and show it individually on the art scene.• Research problem: Is it possible to get out of the literary value of the Arabic letter to the value of visual organic form?• Research aim: Disclosing the creative and organic aspects of the Arabic character.• Research methodology: Analytical Descriptive Approach - Experimental Method.• Key Words: A vision of an organic form of the Arabic alphabet - Arabic CalligraphyDr. Mahmoud Farid Mahmoud Prof. Mohamed Hazem Fathallah Doctor Of Graphic- Dep. Of Graphic Professor Of Graphic- Dep.Of GraphicFaculty Of Fine Art- Helwan University Faculty Of Fine Art- Helwan University Former Vice President of Helwan University