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Effect of Ion Beam Implantation Ofn Morphological, Electrical and Optical Properties of Polymer

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Author

Shafaq Arif

Program

PhD

Institute

Lahore College for Women University

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13323/1/Shafaq_Arif_Physics_2017_HSR_LCWU_Lahore_15.09.2017.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725974705

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In recent years, the demand of polymers is growing progressively in a wide variety of fields extending from everyday life to medical and high technological applications due to their unique inherent properties like lightweight, flexibility, weather and corrosion-resistance and low cost. Considering the bulk properties of polymer an effort has been made to modify the structural, morphological, electrical and optical properties of near-surface layer of polymer by ion implantation. Indeed, it is a useful technique to modify surface properties of polymers without altering their bulk properties. In particular, with an improvement in electrical conductivity the implanted polymer can be utilized as a promising candidate for its future utilization in the field of plastic electronics. In the present study, the effects of 400 keV C+, Cr+ and Ag+ ion implantation on Polymethylmethacrylate (PMMA) have been examined at different ion fluences ranging from 5x1013 to 5x1015 ions/cm2. The ion penetration depths have been estimated with the help of SRIM simulation. The chemical and structural modifications in implanted PMMA are examined by Fourier Transform Infrared and Raman Spectroscopy (FTIR), respectively. The surface topographical examination of the implanted polymer has been performed using Atomic Force Microscope (AFM). The effects of ion implantation on electrical and optical properties of PMMA have been investigated by four probe apparatus and UV–Visible spectroscopic analysis. The FTIR spectra confirmed the formation of C = C bonds in C+ and Cr+ implanted PMMA at a fluence of 5 × 1015 ions/cm2 while for Ag+ implanted PMMA the peak for C=C is developed at relatively lower fluence of 1 × 1015 ions/cm2. Moreover, the Raman spectra justified the growth of sp2 carbon clusterization and transformation of C+, Cr+ and Ag+ implanted layer of PMMA into quasi-continuous amorphous carbon at implantation fluence of about ≥5x1014 ions/cm2. The AFM images showed the topographical modification due to ion implantation on PMMA. However, the extent of modification depends on the type of ions and increase in ion fluence. The roughness analysis revealed the smoothness of the surface of C+ and Cr+ implanted PMMA with increasing ion fluence. On the other hand, the implantation of Ag+ ions showed dominant effects on the surface of PMMA rather than C+ and Cr+ implantation. As a result, the surface of Ag+ implanted PMMA became rougher due to the formation of nano-hillocks and nano sized grainy structures above the surface. Due to ion-induced structural modifications the electrical conductivity of PMMA is increased to semiconducting range with a rise in ion fluence. After C+ ion implantation the electrical conductivity of PMMA is increased from 2.14 × 10-10 S/cm (pristine) to 1.46 × 10-6 S/cm. Similarly, for Cr+ and Ag+ ion implantation the electrical conductivity has improved to 7.21 × 10-6 S/cm and 9.60 × 10-6 S/cm, respectively. The results of UV-Visible analysis also confirmed an increase in sp2 carbon clusters in implanted PMMA in the favor of other results. Due to creation of carbonaceous clusters the optical absorption spectra of PMMA exhibit a shift towards higher wavelength after C+, Cr+ and Ag+ implantation along with a significant reduction in the optical band gap energies. For C+ implanted PMMA the optical band gap is reduced from 3.13 (pristine) to 0.66 eV whereas, after Cr+ and Ag+ ion implantation it shrinks to 0.85 and 0.81 eV, respectively.
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سلطان کھاروی دیپنجابی نظم نگاری

سلطان کھاروی دی پنجابی نظم نگاری

نظم توں مراد شعراں دا اوہ مجموعہ جیہدے وچ کوئی اک مرکزی خیال ہوندا اے ۔بہت زیادہ شعر ہون پاروں خیال دی درجہ بدرجہ بڑھوتری ظاہر کرن خاطر شعراں نوں وکھ وکھ حصیاں وچ ونڈ لیا جا ندا اے تاں جے نظم دے معنی تے مفہوم واضح ہو سکے ۔نظم وچ اکو خیال نوں سرنانواں بنایا جا ندا اے ۔ایس وچ شعراں دی گنتی دی کوئی حد مقرر نہیں ہو ندی ۔کیول خیال دی ایکتا نوں مکھ رکھیا جاندا اے ۔

ایس لئی سرنانویں دی کوئی پابندی نہیں ۔کسے وی سرنانویں اتے وچاراں دی سانجھ پائی جا سکدی اے ۔بھانویں اوس سر نانویں دا تعلق تاریخ نال ہووے یا ںجغرافیہ نال ،دینی ہووے یاں دنیاوی ،تہذیبی ہووے یاں ثقافتی ،سیاسی ہووے یاں دھرمی،قومی ہووے یاں انقلابی ،نواں ہووے یاں پرانا،علمی ہووے یا ں ادبی ہر پکھ تے دنیا دے ہر معاملے ،حیاتی دے ہر مسئلے تے کائنات دے ہر پکھ بارے نظم لکھی جا سکد ی اے ۔

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دور الإنفاق في سبیل اللہ في رفاھیة المجتمع المعاصر في ضوء فقه السیرۃ

Spending in the cause of Allh is one of the most important ways for the welfare of society and all the divine books agreed about its vital role in the betterment of human lives. But it is obvious from Quraan that not everyone has capacity for it but only those who are saved from stinginess: And whoever is protected from the stinginess of his soul - it is those who will be the successful. (Al-Hashr: 09) It is also very relevant question in this regard that what should be spent? And how and where should be spent? Hence only that type of spending which is according to the need of time is worthy to be called as best use of it, as Prophet (Peace be upon Him) pointed out to the charity of water when Saad ibn e ubadah asked him about the best mean of charity after the death of his mother and people were in urgent need of water. So it is clear that the one who intended to charity must have the actual and original idea about the demand of those who are in crises and then he should decide to arrange the appropriate means in this regard. We found crystal clear indications in the seerat ur rasool (Peace be upon Him) about the appropriate spending in accordance with the demands of current time like the encouraging the release of slaves especially in the Makkah and the treaty of brotherhood among the immigrants and the ansaar and promoting the building of prophetic mosque and preparing the army for battles and promising the abode in paradise in response. This article deals with role of charity in welfare of current society by the proper means and ways, some of the important points are as follows: 1. Introduction. 2. Importance of Infaq in Quraan and Sunnah. 3. Examples of charity in accordance with the demands of society in light of seerah. 4. Charity endowments and its role in the well-being of society in the light of fiqh us seerah. 5. The needs of contemporary society and the role of Charity endowments. 6. Pre-protection from negativity, because prevention is better than cure. 7. Recommendations or proposals for proper expenditure

Biological Evaluation, Isolation and Characterization of Compounds from Fagonia Cretica L.

The research work presented in this thesis deals with the chemotherapeutic (antiproliferative) and cancer chemopreventive activity of a medicinal plant from Pakistan; Fagonia cretica L. (Zygophyllaceae), based on the traditional claims for its use in folklore medicine in the treatment of different types of cancers and inflammatory conditions. Through a bioactivity guided fractionation approach, the crude extract (FCC), resultant two organic fractions i.e. n-hexane and ethyl acetate (FCN and FCE, respectively) and an aqueous fraction (FCA) were tested for their anti-proliferative and cancer chemopreventive activity by employing different standard bioassays. In this investigation, it was demonstrated that F. cretica extract and fractions have antiproliferative activity towards human breast cancer cells and it can exert cancer chemopreventive effects via NFκB inhibition, iNOS inhibition and QR induction. The most potent fraction was ethyl acetate (FCE) fraction followed by n-hexane fraction (FCN) in this study. Six compounds in total (FCEE1, FCEK2, FCEK3, FCEM4, FCEN5 and FCNC6) were isolated from potent fractions of this medicinal plant using repeated flash column chromatography. Structural elucidation was carried out through a series of spectroscopic experiments (1-D and 2-D NMR). Among these six compounds, one compound (FCEE1) is a triterpene acid, two compounds (FCEK2 and FCEN5) belong to the triterpene saponin class, one compound FCEM4 belongs to steroidal saponin class and two compounds (FCEK3 and FCNC6) belong to phytosterol class of chemical compounds. All the isolated compounds have known structures but these are isolated from this plant species for the first time. All the compounds were evaluated for their anti-proliferative activity against breast cancer cell lines (MCF-7 and MDAMB- 231), non-tumorigenic breast epithelial cell line (MCF-10A) and cervical cancer cell line (HeLa) by using sulforhodamine B (SRB) assay. Cancer chemopreventive potential of compounds was also estimated in different bioassays i.e. TNF-α activated nuclear factor-kappa B (NFκB) assay, inhibition of lipopolysaccharide (LPS)- activated nitric oxide (NO) production in murine macrophage RAW 264.7 cells (iNOS) assay, Aromatase inhibition assay and Quinone reductase 1 (QR1) induction assay. A serial dilution of eight concentrations (0.39, 0.78, 1.56, 3.12, 6.25, 12.5, 25, 50 μM) for each compound was tested. xix Purified compounds were able to reduce cell viability significantly in two phenotypically different breast cancer cell lines (MCF-7 and MDA-MB-231). This activity was markedly reduced in normal mammary epithelial cells (MCF-10A) thus indicating selective toxicity between malignant and normal cells. Among compounds, in NFκB inhibition assay, FCEE1 showed maximum inhibition (IC50, 5.26 μM) while in iNOS inhibition assay, FCEM4 demonstrated best activity (IC50, 0.38 μM). For QR1 induction, FCNC6 was proved to be best compound (CD, 17.07 μM). None of the compounds were active in inhibiting aromatase enzyme. Compound FCEE1, a triterpene acid was the most potent compound in this study followed by FCEM4. Elucidation and characterization of the cytotoxic mechanism was undertaken by cell cycle status, apoptosis and expression of transcription factors and their targets i.e. p53, p21, Bax, γ-H2AX and FOXO3a. Pure compound treatment was able to induce a time and dose-dependent decrease on cell viability of two phenotypically different breast cancer cell lines (MCF-7 and MDA-MB-231), while demonstrating a markedly decreased cytotoxic effect of triterpene acid (FCEE1) and derivatives i.e. triterpene saponins (FCEK2 and FCEN5) on normal mammary epithelial cells (MCF-10A). Cell cycle arrest (expressed by sub-G1 peak) and apoptosis was induced in both MCF-7 and MDA-MB-231 cells. Overall all the purified compounds were more effective against estrogen receptor negative breast cancer (MDA-MB-231) cells. Loss of breast cancer cell viability is associated with induction of DNA double strand breaks which were detected in both cell lines by pure compounds’ treatment. In MCF-7 cells, expression of p53 by FCEE1 seems to induce upregulation of the CDK inhibitor, p21, and pro-apoptotic Bax. In current study, pure compounds’ treatment to human breast cancer cells induced double strand breaks to DNA associated with activation of DNA repair protein γ-H2AX. Compound FCEM4 treatment was able to induce FOXO3a expression in both MCF-7 and MDA-MB-231 cells. This suggests that activation of FOXO3a in the absence of functional p53 plays a vital role in induction of cytotoxicity. The results of this study suggest that FCEE1 is cytotoxic through p53 dependent as well as independent pathways while FCEM4 uses only p53 independent pathway.