Advances in Chemistry Research, Volume 21

Book Preface

This book presents original research results on the leading edge of chemistry research. Each article has been carefully selected in an attempt to present substantial research results across a broad spectrum. Topics discussed include the antibacterial and antifouling properties of lipophilic bismuth compounds; rheology of carbon black suspensions; characterization of carbon blacks; doubly bonded molecules containing bismuth and other group 15 elements in the singlet and triplet states; growth of nanocrystals from amorphous bi; mathematical theory of noble gases; and properties of rarefied noble gas flows.

The medicinal and biological properties of elemental bismuth are known to be enhanced by chelating it with lipophilic thiols. In Chapter 1, the authors summarize the antibacterial and antifouling potential of selected lipophilic bismuth compounds largely in the context of environmental, medical, and biotechnological applications. They synthesized ionic and nanoparticulate forms of lipophilic bismuth and determined their minimum inhibitory concentrations (MICs) under environmentally relevant conditions for several Gram-negative bacteria. Bacterial production of extracellular polymeric substances can be effectively suppressed by bismuth thiols at sub- or near- MIC concentration with negligible effect on growth. The authors focus on a cationic di-thiol, viz. bismuth-2, 3-dimercapto-1-propanol (BAL) prepared using a 2:1 Bi:BAL molar ratio since it is stable over a wide pH range and does not carry the malodor or toxicity of BAL. This BisBAL formulation is particularly effective in inhibiting bacterial cohesion and adhesion even at sub- MICs by decreasing EPS secretion, inhibiting acetylation and carboxylation of polysaccharides, and altering protein secondary structures. Results indicate that bismuth thiols could be used to probe and mechanistically understand specific roles of cell-bound and free-EPS in bioflocculation, cohesion, and adhesion without affecting growth. They also synthesized rhombohedral crystalline BisBAL nanoparticles by reducing the BisBAL aqueous complex using an ice-cold solution of sodium borohydride. These nanoparticles also inhibited bacterial growth, prevented bacterial attachment to surfaces, and impaired preformed/established biofilms. They therefore hypothesize that embedding bismuth nanoparticles will impart antimicrobial and antifouling properties to surfaces given their high surface area-to-volume ratio and their ability to slowly release bioactive bismuth in situ over long timeframes due to their lipophilicity. This may provide the basis for developing bismuthnanoparticle based broad-spectrum antimicrobial agents, which could “seek and destroy” microorganisms in a variety of practical applications.

CONTENTS
Preface vii
Chapter 1 Antibacterial and Antifouling Properties of Lipophilic Bismuth Compounds 1
Appala Raju Badireddy and Shankararaman Chellam

Chapter 2 Rheology of Carbon Black Suspensions 29
Yuji Aoki

Chapter 3 Characterization of Carbon Blacks by High Resolution N2Adsorption Isotherms from P/Po=10-7 to P/Po=0.998: Application of Standard α s Data to Analysis of Microporosity of Activated Carbons 97
Kazuyuki Nakai, Yoko Nakada, Masako Hakuman, Joji Sonoda, Masayuki Yoshida and Hiromitsu Naono

Chapter 4 Doubly Bonded Molecules Containing Bismuth and Other Group 15 Elements in the Singlet and Triplet States 149
Ming-Der Su

Chapter 5 Growth of Nanocrystals from Amorphous Bi 185
G. N. Kozhemyakin, S. Y. Kovalev, O. N. Ivanov and O. N. Soklakova

Chapter 6 Mathematical Theory of Noble Gases 197
V. P. Maslov

Chapter 7 Properties of Rarefied Noble Gas Flows 221
Lajos Szalmás
Index