Optimization of a Laser Plasma X-Ray Source for Ultrafast X-Ray Absorption Spectroscopy

Mazhar Iqbal,Muhammad Ijaz,Do Young Noh,Karol A. Janulewicz,Holger Stiel,Peter V. Nickles 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.10

We present optimization of laser plasma x-ray experimental conditions for ultrafast x-ray absorption spectroscopy measurements on broad range of transition metal oxides. First, the x-ray flux generated from a laser plasma source was optimized with an emphasis on the Bremsstrahlung by investigating the influence of the angle of the incidence of laser beam on a Cu tape target. The x-ray flux emitted in both the front and transmitted side of the target was found to be optimal at the incident angle of 15 25 degrees. Moreover the manipulation of the Bremsstrahlung peak energy by the laser focus distribution was discussed. In addition to the source optimization, we present a scheme to find the time-delay zero position in a pump-probe experiment together with a normalization scheme for x-ray source fluctuations. As a feasibility check, we present the transmitted spectra of two materials, Ni and NiO.

Effects of Artificial Ageing on Viability and Leachate Exudation in Fenugreek (Trigonella foenum-grraecum L.) Seeds

Mazhar Abbas,M. Mumtaz Khan,M. Javed Iqbal,Rashid W. Khan 한국원예학회 2004 Horticulture, Environment, and Biotechnology Vol.45 No.5

The effects of environmental treatments to rapidly shorten seed viability in fenugreek (Trigonella foenumgrraecum L.) were explored. Seed germination capacity, seedling vigor (measured as radicle length), and seed leachate conductivity were measured in relation to the ageing process. Artificial ageing significantly reduced the final germination percentage and radicle length. Loss of viability and declining vigor were associated with increased solute leakage. Germination percentage was reduced up to 58% after 7 days of artificial ageing compared to the non-aged control (100%). Following artificial ageing, radicle length was reduced from 0.73 to 0.23 ㎝. The results indicated that a reduction in seed viability and vigor followed by membrane disruption might play a considerable role in deterioration of fenugreek seeds.

Synthesis and thermal properties of polyimides containing azomethine linkage for processable high-performance engineering plastics

Rubbia Iqbal,Muhammad Kaleem Khosa,Muhammad Asghar Jamal,Mazhar Hamid 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

A new series of polyimides having azomethine functionality in backbone was synthesized by two-stepspolycondensation method. Five substituted aromatic diamines--N-(4-aminobenzylidene)-2chloro-6-methylbenzene-1,4-diamine (DA1), N-(4-aminobenzylidene)-2-methoxybenzene-1,4-diamine (DA2), N-(4-aminobenzylidene)-2-methylbenzene-1,4-diamine (DA3), N-(4-aminobenzylidene)-3-methylbenzene-1,4-diamine (DA4) and N,(4-aminobenzylidene)-2-hydroxybenzene-1,4-diamine (DA5)--were prepared and condensed with 3,4,9,10-perylenetetracarboxylicdianhydride (PTCDA) to obtain poly(azomethine imide). All synthesized polyimides PI(1-5) were fully characterizedby elemental analyses, FTIR, 1H-NMR, having amorphous nature and are soluble in dmac, dmf, and dmso, m-cresoldue to presence of azomethine functionality. The inherent viscosities and moisture absorption of all polyimides lie inthe range of 0.65-0.85 dL gm−1 and 0.68-0.82% respectively. Thermal stability was assessed by 10% weight loss temperatureand the degradation temperature of the resultant polymers falls in the ranges from 480-535 oC in nitrogen. Theglass transition temperature was in the range of 225-330 oC. Due to above mentioned attractive properties, polyimidebasedmaterial are attractive for processable high-performance engineering plastics and starting material for fabricationof new polymers.

Production of Hydrogen and Carbon Nanotubes from Catalytic Decomposition of Methane over Ni:Cu/Alumina Modified Supported Catalysts

Hussain, Tajammul,Mazhar, Mohammed,Iqbal, Sarwat,Gul, Sheraz,Hussain, Muzammil,Larachi, Faical Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.7

Hydrogen gas and carbon nanotubes along with nanocarbon were produced from commercial natural gas using fixed bed catalyst reactor system. The maximum amount of carbon (491 g/g of catalyst) formation was achieved on 25% Ni, 3% Cu supported catalyst without formation of CO/CO2. Pure carbon nanotubes with length of 308 nm having balloon and horn type shapes were also formed at 673 K. Three sets of catalysts were prepared by varying the concentration of Ni in the first set, Cu concentration in the second set and doping with K in the third set to investigate the effect on stabilization of the catalyst and production of carbon nanotubes and hydrogen by copper and potassium doping. Particle size analysis revealed that most of the catalyst particles are in the range of 20-35 nm. All the catalysts were characterized using powder XRD, SEM/EDX, TPR, CHN, BET and CO-chemisorption. These studies indicate that surface geometry is modified electronically with the formation of different Ni, Cu and K phases, consequently, increasing the surface reactivity of the catalyst and in turn the Carbon nanotubes/H2 production. The addition of Cu and K enhances the catalyst dispersion with the increase in Ni loadings and maximum dispersion is achieved on 25% Ni: 3% Cu/Al catalyst. Clearly, the effect of particle size coupled with specific surface geometry on the production of hydrogen gas and carbon nanotubes prevails. Addition of K increases the catalyst stability with decrease in carbon formation, due to its interaction with Cu and Ni, masking Ni and Ni:Cu active sites.

The Impact of Demographic Characteristics of Board of Directors and Audit Committee on Financial Reporting Quality: An Empirical Study from Pakistan

Sanober SHAHEEN,Muhammad Mazhar IQBAL 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.1

This study examines the impact of female representation on board of directors and audit committees on financial reporting quality, which also discusses the moderating role of family ownership in female representation on boards of directors and audit committees and financial reporting quality. The unbalanced panel is made up of 271 non-financial companies listed on the Pakistan Stock Exchange (PSX) from 2008 to 2019.The findings reveal that female representation on the board of directors has a large and negative impact on financial reporting, but female representation on the audit committee has a significant positive impact on financial reporting quality. Furthermore, the results reveal that family ownership has a negative impact on the relationship between female presence on boards of directors and financial reporting quality. Furthermore, the findings show that family ownership reduces the impact of female involvement in audit committees on the quality of financial reporting. However, family ownership has no direct impact on financial reporting quality.Our findings suggest that selecting females to serve on boards of directors and audit committees should be based on specific criteria (e.g., monitoring abilities, business competence, knowledge, and experience) rather than on family relationships.

The Relationship Between Capital Structure and Firm Performance: New Evidence from Pakistan

Zia ul ISLAM,Muhammad Mazhar IQBAL 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.2

The necessity for a theoretical explanation of the negative association between capital structure and company performance is identified in this study. By focusing on accounting metrics of business performance, this study is the first to investigate the moderating effects of firm size between these variables using logical reasoning. Due to the possibility of endogeneity, this study applies a two-step system GMM approach with data from 285 non-financial enterprises from PSX over a 21-year period. For robustness, we employed pooled OLS, fixed effect, and two-step difference GMM. Our data show that leverage has a detrimental impact on business performance, with size acting as a moderator in the same direction. Our analysis empirically supports some studies while refuting others due to inconsistent results in the literature, but no study has theoretically justified their negative link. We believe that because larger companies have more and easier access to capital markets, they focus primarily on the amount of return, even if the investment is inefficient in terms of the rate of return, but small businesses do not. As a result of this thinking, firm managers’ performance suffers as a result of leverage.

Production of hydrogen and Carbon Nanotubes from atalytic Decomposition of Methane over Ni:Cu/Alumina Modified Supported catalysts

Tajammul Hussain,Mohammed Mazhar,Sarwat Iqbal,Sheraz Gul,Muzammil Hussain,Faical Larachi 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.7

Hydrogen gas and carbon nanotubes along with nanocarbon were produced from commercial natural gas using fixed bed catalyst reactor system. The maximum amount of carbon(491 g/g of catalyst) formation was achieved on 25% Ni, 3% Cu supported catalyst without formation of CO/CO2. Pure carbon nanotubes with length of 308 nm having ballon and horn type shapes were also formed at 673K. Three sets of catalysts were prepared by varying the concentration of Ni in the first set, Cu concentration in the second set and doping with K in the thired set to investigate the effect on stabilization of the catalyst and production of carbon nanotubes and hydrogen by coper and potassium doping. Particle size analysis revealed that most of the ctalyst particled are in the range of 20-35 nm. All the catalysts were characterized using powder XRD, SEM/EDX, TPR, CHN, BET and CO-chemisorption. These studies indicate that surface geometry is modified electronically with the formation of different Ni, Cu and K phases, consequently, increasing the surface reactivity of the catalyst and in turm the Carbon nanotubes/H2 production. The addition of Cu and k enhances the catalyst dispersion with the increase in Ni loadings and maximum dispersion is achieved on 25% Ni: 3% Cu/Al catalyst. Clearly, the effect of particle size couple with specific surface geometry o nthe production of hydrogen gas and carbon nanotubes prevails. Addition of K increases the catalyst stability with decrease in carbon formation, due to its interaction with Cu and Ni, masking Ni and Ni: Cu active sites.

Outcomes of Triple-Negative Versus Non-Triple-Negative Breast Cancers Managed with Breast-Conserving Therapy

Bhatti, Abu Bakar Hafeez,Khan, Amina Iqbal,Siddiqui, Neelam,Muzaffar, Nargis,Syed, Aamir Ali,Shah, Mazhar Ali,Jamshed, Arif Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Background: Triple negative breast cancer is associated with aggressive behavior and high risk of local and regional failure. Aggressive surgical intervention is considered suitable. This makes role of breast conserving therapy (BCT) debatable in these patients. The objective of this study was to compare outcome of BCT for triple negative versus non-triple negative breast cancer. Materials and Methods: Medical records of patients who underwent breast conserving therapy from 1999 to 2009 at Shaukat Khanum Cancer Hospital and had complete receptor status information were extracted. Patients were divided into triple negative breast cancer (TNBC) and non-TNBC. Patient characteristics, medical treatment modalities and adverse events were compared. Expected five year locoregional recurrence free, disease free and overall survival was calculated. The Cox proportional hazard model was used to identify independent predictors of outcome. Results: A total of 194 patients with TNBC and 443 with non-TNBC were compared. Significant difference was present for age at presentation (p<0.0001), family history (p=0.005), grade (p<0.0001) and use of hormonal therapy (p<0.0001). The number of locoregional failures, distant failures and mortalities were not significantly different. No significant difference was present in 5 year locoregional recurrence free (96% vs 92%, p=0.3), disease free (75% vs 74%, p=0.7) and overall survival (78% vs 83%, p=0.2). On multivariate analysis, tumor size, nodal involvement and hormonal treatment were independent predictors of negative events. Conclusions: Breast conserving therapy has comparable outcomes for triple negative and non-triple negative breast cancers.

Combined application of biochar, compost, and bacterial consortia with Italian ryegrass enhanced phytoremediation of petroleum hydrocarbon contaminated soil

Hussain, Fida,Hussain, Imran,Khan, Aqib Hassan Ali,Muhammad, Yousaf Shad,Iqbal, Mazhar,Soja, Gerhard,Reichenauer, Thomas Gerhard,Zeshan, Thomas Gerhard,Yousaf, Sohail Elsevier 2018 Environmental and experimental botany Vol.153 No.-

<P><B>Abstract</B></P> <P>Petroleum hydrocarbons are extensively utilized in petrochemical industries and cause soil deterioration during exploration, transportation, refining and making petroleum products. We hypothesized that the combined use of compost, biochar and bacterial consortia as soil amendments may enhance the rhizoremediation potential of ryegrass by strengthening the plant rhizospheric effect for efficient total petroleum hydrocarbon removal. The present study focused on phytoremediation of hydrocarbons in spiked contaminated soil amended with biochar (5% v/v), and compost (5% v/v). Spiked soil was inoculated with consortia of four hydrocarbon degrading bacterial strains (<I>Pseudomonas poae, Actinobacter bouvetii, Stenotrophomonas rhizophila</I> and <I>Pseudomonas rhizosphaerae</I>). The spiked soil was prepared by spiking agricultural soil with 3.4% (w/w) of crude oil. Italian ryegrass (60 seeds pot<SUP>−1</SUP>) were sown and plants were harvested after 75 days.</P> <P>The highest hydrocarbon removal (85%) was observed in spiked soil amended with compost, biochar and consortia. Bacterial inoculation with biochar and compost showed significantly higher hydrocarbon degradation as compared to all other treatments. Highest TPHs degrading bacteria (5.74 × 10<SUP>7</SUP> cells g<SUP>−1</SUP> of soil) were observed in rhizosphere of spiked soil amended with compost, biochar and consortia. The organic amendments improved plant growth and bacterial count in rhizosphere which resulted in higher removal of hydrocarbons. We concluded that plant-microbe interactions together with the organic soil amendments offer an emerging trend for remediation of hydrocarbons. Rhizoremediation is a green solution to overcome the quandary of total petroleum hydrocarbon contamination in soil.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biochar and compost amendment enhanced rhizosphere effect. </LI> <LI> TPHs Rhizoremediation is improved by bacterial consortia and organic amendments. </LI> <LI> The organic amendments improved plant growth and bacterial count in rhizosphere. </LI> <LI> Compost is a rich source of bacteria in the rhizosphere. </LI> </UL> </P>

Some Pyridyl- and Thiophenyl- Substituted 1,2,4-Triazolo[3,4-b]1,3,4-thiadiazole Derivatives as Potent Antibacterial

Muhammad Rizwan Maqsood,Muhammad Hanif,Muhammad Rafiq,Muhammad Saleem,Sumera Zaib,Aftab Ahmed Khan,Mazhar Iqbal,Jamshed Iqbal,Nasim Hasan Rama,서승염,Ki-Hwan Lee 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

The target compounds 6-11a-e were synthesized by condensing 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones 5a-f with various aromatic carboxylic acids in the presence of phosphorous oxychloride. The structures of newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, elemental analysis and mass spectrometric studies. All the synthesized compounds were screened for their antibacterial activity. Almost all the tested compounds were potent against four different strains of bacteria when compared with that of reference drug ciprofloxacin. Compounds 6c, 6e, 8d, 9b, 9e, 11a and 11b showed nearly equal or lower MIC values than standard drug, against all four tested bacterial strains but rest of the compounds showed excellent antibacterial activities.