Reflections on the journey: six short stories

One of the goals of the 2011 International Year of Chemistry is to celebrate the contributions of women to science. A question that has been frequently asked in this regard is... Why is it necessary to highlight women in the "age of equality"? The reasons are varied but the facts are that many women scientists worked in obscurity throughout the 19th and even well into the 20th century, sometimes publishing anonymously to be heard. This celebration of Women in Science is one way to recognize both the resiliency and passion of these women. As part of this celebration, Chemistry Central Journal's Thematic Series of "Women in Chemistry" includes this article describing the path several women took as they pursued chemistry careers spanning the latter part of the 20th century and into the early 21st century. Sharon Haynie, Nancy Jones, Cheryl Martin, Paula Olsiewski, Mary Roberts and Amber Hinkle each have unique story of their personal journey from childhood to adulthood. As you read these stories, listen generously, and feel free to share your own stories, comments and thoughts.     

Self-assembling viral mimetics: one long journey with short steps

Recently, the Foresight Institute has pronounced six economic challenges that can be addressed through the progress of nanotechnology. One of these is the health and longevity of human life. Amongst applications anticipated to provide a solution to this challenge, gene therapy appears to be particularly promising. In theory, many diseases that result from genetic disorders can be cured by correcting defective genes. In practice, finding efficient and safe delivery vectors remains the stumbling point on the path of genetic therapies to the clinic. Viruses, otherwise the most efficient transfectors, pose safety concerns over immune reactions, whereas synthetic gene packages greatly lack the structural integrity of viruses. An ideal vector is therefore seen as a compromise between the two: a nanoscale device, which would mimic a virus and act as a virus, but would do this at the designer's whim. A strategy to achieve this is offered by the virus architecture itself, the principles of which are translated into the function via exquisitely reproducible self-assembly mechanisms. Thus, to mimic a virus is to mimic the way it is built, i.e., self-assembly. With just a few attempts made so far, the journey to an artificial virus has had a short lifetime, but the promise it holds is not expected to reduce any time soon.     

From molecular insights and chemical technologies to communications and expert systems: A few short thermodynamic stories

This Hugh M. Huffman Memorial Award Lecture illustrates the power of phenomenological and statistical thermodynamics and the unique role of thermochemical data by a variety of studies in very diverse scientific and industrial fields ranging from conformational analysis to optimization of high-tech space and mass-scale chemical technologies and from data communications to data expert systems for chemical process design.     

A journey on the electrochemical road to sustainability

As the nations of the world continue to develop, their industrialization and growing populations will require increasing amounts of energy. Yet, global energy consumption, even at present levels, has already given rise to major concerns over the security of future supplies, together with the attendant twin problems of environmental degradation and climate change. Accordingly, countries are examining a whole range of new policies and technology issues to make their energy futures ??sustainable??, that is, to maintain economic growth and cultural values whilst providing energy security and environmental protection. A step in the right direction is to place electrochemical power sources??serviceable, efficient and clean technology??at the cutting edge of energy strategies, regardless of the relatively low price of such traditional fuels as coal, mineral oil and natural gas. Following a chronicle of the events that led up to the discovery of batteries and fuel cells, the paper discusses the application of these devices as important technology for shifting primary energy demand away from fossil fuels and towards renewable sources that are more abundant, less expensive and/or more environmentally benign. Finally, consideration is given to the idea of introducing hydrogen as the universal vector for conveying renewable forms of energy and also as the ultimate non-polluting fuel. Fuel cells are the key enabling technology for a hydrogen economy. As requested, the paper opens with a brief account of the circumstances by which the author joined others on a fascinating journey on the electrochemical road to sustainability.     

Electrochemical impedance spectroscopy: the journey to physical understanding

Journal of Solid State Electrochemistry -     

Spiroheterocyclic compounds: old stories with new outcomes

An efficient and straightforward method for the preparation of spirodiazine derivatives is reported which involves mild reaction conditions and easily accessible reactants. A new class of spiroazaheterocycles, spiro[pyrrolidine-pyrrolo[3,4-c]pyrroles], is obtained. A feasible explanation is given for the unexpected results obtained at high energy (high temperatures, MW and ultrasound irradiation).     

A journey under the sea: the quest for marine anti-cancer alkaloids

The alarming increase in the global cancer death toll has fueled the quest for new effective anti-tumor drugs thorough biological screening of both terrestrial and marine organisms. Several plant-derived alkaloids are leading drugs in the treatment of different types of cancer and many are now being tested in various phases of clinical trials. Recently, marine-derived alkaloids, isolated from aquatic fungi, cyanobacteria, sponges, algae, and tunicates, have been found to also exhibit various anti-cancer activities including anti-angiogenic, anti-proliferative, inhibition of topoisomerase activities and tubulin polymerization, and induction of apoptosis and cytotoxicity. Two tunicate-derived alkaloids, aplidin and trabectedin, offer promising drug profiles, and are currently in phase II clinical trials against several solid and hematologic tumors. This review sheds light on the rich array of anti-cancer alkaloids in the marine ecosystem and introduces the most investigated compounds and their mechanisms of action.     

Modeling the structure-property relationships of nanoneedles: A journey toward nanomedicine

Innovative biomedical techniques operational at the nanoscale level are being developed in therapeutics, including advanced drug delivery systems and targeted nanotherapy. Ultrathin needles provide a low invasive and highly selective means for molecular delivery and cell manipulation. This article studies the geometry and the stability of a family of packed carbon nanoneedles (CNNs) formed by units of 4, 6, and 8 carbons, by using quantum chemistry computational modeling methods. At the limit of infinite-length, these CNNs might act as semiconductors, especially when the number of terminal units is increased. CNNs are also potentially able to stabilize ions around their structure. Therefore, due to the apolar characteristics of CNNs and their ability to carry ionic species, they would be suitable to act as drug carriers through nonpolar biologic media.     

A journey inside the U28 nanocapsule

Anionic uranyl-peroxide U(28) nanocapsules trap cations and other anions inside, whose structures cannot be resolved by X-ray diffraction, owing to crystallographic disorder. DFT calculations enabled the complete characterization of the geometry of these complex systems and also explained the origin of the disorder. The stability of the capsules was strongly influenced by the entrapped cations. Excellent agreement between experiment and theory was also obtained for the electronic character and redox properties.     

Reflections on the reform of education

Analysis of the Russian education reform results is given. Negative effects of the reform (an increase in the number of paid educational institutions providing low quality education, disproportion in training of specialists, an increase in the paid education sector etc.) and causes of these effects are described. A way to correct the situation in the field of national education is pointed out.     

A lifetime journey into the world of chemistry

The professional life of the author has been a fascinating journey through the magnificent landscapes of synthetic organic chemistry. A friendly editor invited him to share a few of these travel memories. This review is thus a (very) personal and (totally) prejudiced account of the author's research in organic chemistry. It describes the work of his associates and coworkers at UCLouvain in Belgium or at IECB in France. All schemes only deal with work which was done in both research groups. The names of the coworkers will appear in the references. The author apologizes to those coworkers whose work has not been cited but he had to sail within his pages' allocation. As will be seen, many areas of organic synthesis have been visited. The results of the research were put into perspective with the status of the field when the research was undertaken. Obviously several of these fields of research have dramatically expanded later on; credit could not be given here to these important developments. However, when available, some recent reviews will be cited to give a flavour of the most recent work. Thus, the reader should not expect to read a “classical” review of a topical subject. The purpose of this paper is merely the sharing of professional experiences of a modest but enthusiastic teacher and researcher.     

Chemistry with the electron microscope: some highlights in a lifetime's journey.

The supreme advantages of electron microscopy (EM) in the chemical sciences are briefly recalled: By judicious use of electron optical techniques, vital information of a structural, mechanistic, compositional, and often of an electronic kind may be retrieved. Not only are insights gained (through EM) into the existence of whole new families of structures hitherto unperceived, but one also uncovers the structural characteristics of imperfections in solids. And it is often the case that these imperfections reflect or suggest altogether new structures, hitherto unconceived. EM is , therefore, a powerful agent for aiding chemical synthesis of new materials. This is particularly important in the field of heterogeneous catalysis, since altogether new types of catalytic materials may be, on the one hand, defined, described, identified, and characterised, and, on the other, designed and synthesised. There is also the ever-improving role of the electron microscope as an analytical tool: Very few other techniques within reach of the chemist can rival it in tis sensitivity and detection limits. (Scanning instruments now permit the imaging and the identification of nanoclusters consisting of just a few atoms.) But there are numerous other branches of chemistry besides catalysis and surface science where EM proves invaluable, as we outline herein, in elucidating structure-property or composition and structure interrelationships.     

Reflections on the ideal analytical text book

Summary Proceeding from the Fresenius Textbook on Analytical Chemistry, which was variously imitated and modified in the course of time, it is shown that at present none of the existing texts is fully satisfactory. The need for a book presenting the material in an effective style and format is pointed out.

---

Überlegungen zum idealen analytischen Lehrbuch

Zusammenfassung Ausgehend von Fresenius' Lehrbuch der Analytischen Chemie, das im Laufe der Zeit zahlreiche Abwandlungen und Nachahmungen erfahren hat, wird darauf hingewiesen, daß z. Zt. kein in jeder Hinsicht vollbefriedigendes Werk existiert. Die Notwendigkeit für ein in Stil und Format den modernen Erfordernissen entsprechendes Lehrbuch wird aufgezeigt.

     

Metallic organophosphates as catalysts in asymmetric synthesis: a return journey

This perspective article provides a general overview of the most relevant topics in the applications of chiral metallic organophosphates. A brief introduction along with a historic comparative profile of the BINOL and phosphoric acid analogues are given. Next, a selection of the most outstanding uses of the catalysts according to the employed metal is presented.     

Sustainable approach on the biodegradation of azo dyes: A short review

1. Download : Download high-res image (207KB)
2. Download : Download full-size image

     

Structural relationships in tetrahedral frameworks: Reflections on cristobalite

Twinning on the unit cell level of the idealized cristobalite structure, using a mirror plane as the twin and composition plane, provides a simple relationship between 14 tetrahedral frameworks. Of these, 9 are found among the aluminosilicates with examples ranging from (stuffed) silicas to zeolites and include the framework types of nepheline hydrate I, zeolite LiA(BW), gismondine, phillipsite, merlinoite, tridymite, paracelsian, and monoclinic CaAl₂Si₂O₈. Similar twinning relates the frameworks of natrolite, thomsonite, and edingtonite.     

分业：“五四”后关于文化运动的反思

“五四”学生运动多被视作文化运动向政治运动转向的开端,从长时段来看,这一判断应无疑义。若从短程视野观察,“五四”运动结束后一段时间内,或出于反思性目的,不少青年学生在原有文化运动道路上有继续深入与前行的倾向,主要表现为越来越多的人抱持一种文化运动的分工意识,“分业”渐成一时流行的口号。这一倾向在少年中国学会内部表现尤为明显,不少学会成员在分工原则的指导下,自觉担负起思想学术方面的使命,在既有的社会运动之外,明确宣告“力学救国”。     

Thermodynamic study on the sublimation of six methylnitrobenzoic acids

The Knudsen mass-loss effusion technique was used to measure the vapour pressures at different temperatures of the following six compounds: 2-methyl-3-nitrobenzoic acid, between T =  357.16 K and T =  371.16 K; 2-methyl-6-nitrobenzoic acid, between T =  355.16 K and T =  369.16 K; 3-methyl-2-nitrobenzoic acid, between T =  371.16 K and T =  385.14 K; 3-methyl-4-nitrobenzoic acid, between T =  363.21 K and T =  379.16 K; 4-methyl-3-nitrobenzoic acid, between T =  363.10 K and T =  377.18 K; 5-methyl-2-nitrobenzoic acid, between T =  355.18 K and T =  371.08 K. From the temperature dependence of the vapour pressure, the standard molar enthalpies of sublimation were derived by the Clausius–Clapeyron equation and the molar entropies of sublimation at equilibrium pressures were calculated. Using estimated values for the heat capacity differences between the gas and the crystal phases of the studied compounds the standard, p^o =  10⁵Pa, molar enthalpies Δ_cr^gH_m^o, entropies Δ_cr^gS_m^oand Gibbs energies Δ_cr^gG_m^oof sublimation at T =  298.15 K, were derived: