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Mazhar Ul-Islam,Muhammad Wajid Ullah,Shaukat Khan,박중곤 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6
Bacterial cellulose (BC), an important biopolymer, has gained tremendous interest in several fields in the last few decades. Despite having the same chemical structure as plant cellulose, BC is superior in physical appearance and purity, as well as in mechanical, crystallinic, and biological properties for multiple applications. Despite these features, BC has limitations in production cost as well as physiological features. Notable limitations, including a non-bactericidal nature, low biocompatibility, and lack of conductive and magnetic properties, have been compensated through the development of composites using nanomaterials and polymers. Similarly, the limitation associated with cost has been reduced by developing new BC synthesis strategies, designing novel bioreactors, using genetically modified microbial species, and exploring alternative cheap fermentation media. Successful BC production has been reported from the use of industrial, confectionary, municipal and other wastes, including coconut water and fruit juices. Herein, we overview various efforts made thus far in identifying waste byproducts and inexpensive carbon sources for cost-effective BC production. It also provides information about the BC market and selling price, as well as techno-economic analysis of biotechnological BC production. This review article includes findings reported in the last few decades, and we hope it will be of great interest for readers as well as commercial BC producers.
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.
Khan, Shaukat,Ul-Islam, Mazhar,Ullah, Muhammad Wajid,Kim, Yeji,Park, Joong Kon Springer-Verlag 2015 CELLULOSE Vol.22 No.4
<P>This study explores the biocompatible behavior of bacterial cellulose (BC) composites with the highly conductive poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). To synthesize this novel composite, we utilized an ex situ penetration method, whereby never-dried BC sheets were incubated with aqueous PEDOT: PSS solution. The resulting composite films were characterized using several analytical tools. Field-emission scanning electron microscopy illustrated the impregnation of PEDOT: PSS into the BC matrix, while the uniform dispersion of PEDOT: PSS in the composites was confirmed with energy-dispersive X-ray spectroscopy. The conductivity of the PEDOT: PSS incorporated BC was 7.3 9 10(-2) +/- 0.021 S/cm with 29.37 +/- 2.13 weight percentage (wt%) of PEDOT: PSS. The biocompatibility of the BC-PEDOT: PSS film was tested against animal fibroblast cells. The composites showed excellent cell adhesion and proliferation. The animal cells showed filopodia formation and interconnectivity during 3 days of incubation. The cytotoxicity of the BC-PEDOT:PSS film was also assayed, confirming the non-toxic nature of this composite. Taken together, our results demonstrate that this novel biocompatible BC-PEDOT:PSS composite could potentially be used for biomedical applications, particularly in the biosensors, drug delivery devices, neural implants, and tissue engineering fields.</P>