Showing papers in "Pure and Applied Chemistry in 2004"
TL;DR: The first version of the IUPAC technical report on chemical actinometers was published in Pure Appl Chem 61, 187-210 (1989) as mentioned in this paper, and since then some methods have been improved, procedures have been modified, and new substances have been proposed as chemical act-inometers.
Abstract: This document updates the first version of the IUPAC technical report on "Chemical actinometers" published in Pure Appl Chem 61, 187-210 (1989) Since then, some methods have been improved, procedures have been modified, and new substances have been proposed as chemical actinometers An actinometer is a chemical system or a physical device by which the number of photons in a beam absorbed into the defined space of a chemical reactor can be determined integrally or per time This compilation includes chemical actinometers for the gas, solid, microheterogeneous, and liquid phases, as well as for the use with pulsed lasers for the measurement of transient absorbances, including the quantum yield of phototransformation, as well as the literature for each of the actinometers The actinometers listed are for the use in the wavelength range from the UV to the red region of the spectrum A set of recommended standard procedures is also given Advantages and disadvantages are discussed regarding the use of chemical actinometers vs electronic devices for the measurement of the number of photons absorbed Procedures for the absolute measurement of incident photon flux by means of photodiodes are also discussed
757 citations
TL;DR: The macrocyclic cyclodextrins (enzymic conversion products of starch) were dis-covered in 1891, and the structures were elucidated in the mid-1930s.
Abstract: The macrocyclic cyclodextrins (enzymic conversion products of starch) were dis- covered in 1891, and the structures were elucidated in the mid-1930s. Their industrial sig- nificance become obvious in the 1970s, and by now thousand of tons of the three cyclo- dextrins (α-, β-, and γCD) and of their chemical derivatives and inclusion complexes are produced industrially. The outer surface of these doughnut-shaped molecules is hydrophilic, but they possess an axial open cavity, which is of hydrophobic character and capable of including other apo- lar molecules (or their moiety) in case of geometric compatibility. This is the essence of mo- lecular encapsulation by inclusion complex formation.
496 citations
TL;DR: In this article, the authors define the Domino Reaction as a process of two or more bond-forming reactions under identical conditions, in which the subsequent transformation takes place at the func- tionalities obtained in the former transformation.
Abstract: Domino reactions are defined as processes of two or more bond-forming reactions under identical conditions, in which the subsequent transformation takes place at the func- tionalities obtained in the former transformation. They allow the efficient synthesis of com- plex molecules from simple substrates in an ecologically and economically favorable way. A very powerful domino process is the domino Knoevenagel-hetero-Diels-Alder re- action, in which an aldehyde or an β-ketoester is condensed with a 1,3-dicarbonyl compound or a heteroanalog to give a 1-oxa-1,3-butadiene, which can undergo an inter- or intramolec- ular hetero-Diels-Alder reaction with dienophiles such as enol ethers or alkenes. The products are dihydropyrans, which can be transformed in a variety of ways. Thus, an extension of the process is the synthesis of highly substituted pyrrolidines, piperidines, and azepanes using aminoaldehydes. The process has also been employed for the enantio- selective total synthesis of a variety of alkaloids, such as indol- and ipecacuanha alkaloids. In another domino process, erythrina and homoerythrina alkaloids have been prepared from simple phenylethylamines and ketoesters.
408 citations
TL;DR: An inventory of theoretical and methodological concepts in electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) is provided in this paper, together with recommendations for the preferred symbols, terminology, and nomenclature.
Abstract: This document provides an inventory of theoretical and methodological concepts in electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) Definitions of basic relationships are given, together with recommendations for the preferred symbols, terminology, and nomenclature Methods of study of ITIES are briefly described, current experimental problems are indicated, and representative experimental data are shown The practical applications of electrochemistry at ITIES are summarized
282 citations
TL;DR: In this paper, a general approach for the synthesis of a broad range of semiconductor nanowires (NWs) with precisely controlled chemical composition, physical dimension, and electronic, optical properties using a metal cluster-catalyzed vapor-liquid-solid growth mechanism was introduced.
Abstract: Semiconductor nanowires (NWs) represent an ideal system for investigating low- dimensional physics and are expected to play an important role as both interconnects and functional device elements in nanoscale electronic and optoelectronic devices Here we re- view a series of key advances defining a new paradigm of bottom-up assembling integrated nanosystems using semiconductor NW building blocks We first introduce a general ap- proach for the synthesis of a broad range of semiconductor NWs with precisely controlled chemical composition, physical dimension, and electronic, optical properties using a metal cluster-catalyzed vapor-liquid-solid growth mechanism Subsequently, we describe rational strategies for the hierarchical assembly of NW building blocks into functional devices and complex architectures based on electric field or micro-fluidic flow Next, we discuss a vari- ety of new nanoscale electronic device concepts including crossed NW p-n diode and crossed NW field effect transistors (FETs) Reproducible assembly of these scalable crossed NW de- vice elements enables a catalog of integrated structures, including logic gates and computa- tional circuits Lastly, we describe a wide range of photonic and optoelectronic devices, in- cluding nanoscale light-emitting diodes (nanoLEDs), multicolor LED arrays, integrated nanoLED-nanoFET arrays, single nanowire waveguide, and single nanowire nanolaser The potential application of these nanoscale light sources for chemical and biological analyses is discussed
252 citations
TL;DR: In this article, the development of palladium, nickel, and rhodium catalysts for the hydroamination of dienes and vinylarenes is described, and the first transition metal-catalyzed aminations of amines that generate terminal amines are described.
Abstract: Studies on the development of palladium, nickel, and rhodium catalysts for the hydroamination of dienes and vinylarenes are described. Enantioselective catalysts based on palladium have been developed for the addition of arylamines to dienes and for Markovnikov addition of arylamines to vinylarenes. In addition, nickel catalysts for the addition of aliphatic amines to dienes have been developed and rhodium catalysts for the first transition metal-catalyzed aminations of vinylarenes that generate terminal amines as the major prod- uct are described. Mechanistic data on the hydroamination of vinylarenes with palladium and rhodium is also provided.
232 citations
TL;DR: In this article, a review of the solvatochromic properties of new hydrophilic and lipophilic betaine dyes with better solubility in water (respectively, nonpolar solvents) is described.
Abstract: Solutions of the zwitterionic betaine dye 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-di- phenylphenolate are solvatochromic, thermochromic, piezochromic, and halochromic. That means the position of its longest-wavelength intramolecular charge-transfer absorption band depends on solvent polarity, solution temperature, external pressure, and the nature and con- centration of added salts. The extraordinarily large negative solvatochromism of this standard betaine dye has been used to establish UV/vis spectroscopically an empirical scale of solvent polarity, called E T (30), respectively E T scale, meanwhile known for many organic solvents and solvent mixtures. In this review, the solvatochromic properties of some new hydrophilic and lipophilic betaine dyes with better solubility in water (respectively, nonpolar solvents), as well as some recent applications of these betaine dyes in various fields of interest (e.g., microheterogeneous (micellar) and polymer solutions, chemical sensors, as well as surface polarity of silicas, aluminas, and cellulose derivatives) are described.
225 citations
TL;DR: The Southern and Eastern Africa Network of Analytical Chemists (SEANAC), Gaborone, Botswana, July 7-10, 2003 as discussed by the authors, presented a conference on the development of analytical chemistry.
Abstract: 30 pages, 2 figures, 2 tables.-- Presented at the Southern and Eastern Africa Network of Analytical Chemists (SEANAC), Gaborone, Botswana, July 7-10, 2003.
207 citations
TL;DR: An overview of methods for chemical speciation analysis of elements in samples of sediments and soils is presented in this article, where the sequential leaching procedure is thoroughly discussed, and examples of different applications are shown.
Abstract: This paper presents an overview of methods for chemical speciation analysis of elements in samples of sediments and soils. The sequential leaching procedure is thoroughly discussed, and examples of different applications are shown. Despite some drawbacks, the sequential extraction method can provide a valuable tool to distinguish among trace element fractions of different solubility related to mineralogical phases. The understanding of the speciation of trace elements in solid samples is still rather unsatisfactory because the appropriate techniques are only operationally defined. The essential importance of proper sampling protocols is highlighted, since the sampling error cannot be estimated and corrected by standards. The Community Bureau of Reference (BCR) protocols for sediment and soil give a good basis for most of the solid samples, and the results can be compared among different laboratories.
181 citations
TL;DR: Azobenzene chromophores can be switched between two geometric isomers using visible light as mentioned in this paper, and the wavelengths effecting the transformation can be tuned synthetically with substituent groups to the chromphores.
Abstract: Azobenzene chromophores can be switched between two geometric isomers using visible light. This photoisomerization is rapid, reversible, and of high quantum yield, and the wavelengths effecting the transformation can be tuned synthetically with substituent groups to the chromphores. Upon isomerization, there can be significant changes to the optical, geo- metric, mechanical, and chemical properties of azobenzene molecules, and these photo- switchable properties can often be transferred to large host systems into which azobenzene is incorporated. This review describes polymers and surfaces that have been prepared recently that incorporate azobenzene groups, and some of the interesting physical and chemical prop- erties that can be switched reversibly as a result.
179 citations
TL;DR: Recent findings of a dextran-based polymeric micelle study for solubilization of a highly lipophilic drug, cyclosporin A (CsA), will be discussed.
Abstract: The oral delivery of drugs is regarded as the optimal means for achieving thera- peutic effects owing to increased patient compliance. Unfortunately, the oral delivery route is beset with problems such as gastrointestinal (GI) destruction of labile molecules, low lev- els of macromolecular absorption, etc. To reduce the impact of digestive enzymes and to en- sure the absorption of bioactive agents in an unaltered form, molecules may be incorporated into microparticulate carriers. Many approaches to achieve the oral absorption of a wide va- riety of drugs are currently under investigation. Among the different polymer-based drug de- livery systems, polymeric micelles represent a promising delivery vehicle especially intended for poorly water-soluble pharmaceutical active ingredients in order to improve their oral bioavailability. Recent findings of a dextran-based polymeric micelle study for solubilization of a highly lipophilic drug, cyclosporin A (CsA), will be discussed.
TL;DR: In this article, the authors define the terms most commonly encountered in the field of polymer reactions and functional polymers, and describe functional polymeric materials as reactive polymeric components of polymers.
Abstract: The document defines the terms most commonly encountered in the field of polymer reactions and functional polymers. The scope has been limited to terms that are specific to polymer systems. The document is organized into three sections. The first defines the terms relating to reactions of polymers. Names of individual chemical reactions are omitted from the document, even in cases where the reactions are important in the field of polymer reactions. The second section defines the terms relating to polymer reactants and reactive polymeric materials. The third section defines the terms describing functional polymeric materials.
TL;DR: In this paper, the late Almeria Natansohn showed that reversible trans-cis-trans photoisomerization of aromatic azo groups covalently bonded within polymers could trigger a variety of motions in the polymer materials at molecular, nanometer, and micrometer lev- els.
Abstract: The following article is a tribute to the late Almeria Natansohn and is based on a brief summary of her research in azopolymers. She showed that reversible trans-cis-trans photoisomerization of aromatic azo groups covalently bonded within polymers could trigger a variety of motions in the polymer materials at molecular, nanometer, and micrometer lev- els. The photoinduced motions could be limited only to the azo rigid chromophore or could involve many polymer chains and ordered domains. Some of the effects of these motions such as reversible photo-orientation of chromophores, amplification effects, photorefractive effects, formation of surface relief gratings (SRGs), and photoinduced chirality and switch- ing in amorphous and liquid-crystalline (LC) polymer films are discussed in relation to the polymer structure and physical parameters. Possible photonic applications originating from these phenomena are also mentioned.
TL;DR: In this article, the authors define the terms most commonly encountered in the field of polymer blends and composites, and describe the morphologies of phase-separated polymeric mixtures.
Abstract: The document defines the terms most commonly encountered in the field of polymer blends and composites. The scope has been limited to mixtures in which the components differ in chemical composition or molar mass and in which the continuous phase is polymeric. Incidental thermodynamic descriptions are mainly limited to binary mixtures although, in principle, they could be generalized to multicomponent mixtures. The document is organized into three sections. The first defines terms basic to the description of polymer mixtures. The second defines terms commonly encountered in descriptions of phase domain behavior of polymer mixtures. The third defines terms commonly encountered in the descriptions of the morphologies of phase-separated polymer mixtures.
TL;DR: A review of the directed construction of supramolecular or-ganic-inorganic compounds from macrocyclic cavit and cucurbit(6)uril can be found in this article.
Abstract: The review surveys new data on the directed construction of supramolecular or- ganic-inorganic compounds from macrocyclic cavitand cucurbit(6)uril (C 36 H 36 N 24 O 12 ) and mono- and polynuclear aqua complexes. Due to the presence of polarized carbonyl groups, cucurbit(6)uril forms strong complexes with alkali, alkaline earth and rare-earth metal ions, and hydrogen-bonded supramolecular adducts with cluster and polynuclear aqua complexes of transitional metals. A wide variety of supramolecular compounds and their unique struc- tures are described.
TL;DR: In this article, the salient features of plant-derived materials are highlighted as potential phytofiltration sources in the recovery of toxic heavy and precious metals, and column studies using support matrices for biomass immobilization such as silica, agar, polyacrilamide, polysulfone, alginates, cellulase, and different crosslinking agents have been performed to improve the biomass adsorption capacity and reusability.
Abstract: Biosorption is a relatively new process that has proven very promising in the removal of contaminants from aqueous effluents. Microorganisms as well as plant- and animal-derived materials have been used as biosorbents by many researchers. Biomaterial immobilization and chemical modification improves the adsorption capacity and stability of biosorbents. Biosorption experiments over Cu(II), Cd(II), Pb(II), Cr(III), and Ni(II) demonstrated that biomass Cu(II) adsorption ranged from 8.09 to 45.9 mg g - 1 , while Cd(II) and Cr(VI) adsorption ranged from 0.4 to 10.8 mg g - 1 and from 1.47 to 119 mg g - 1 , respectively. Mechanisms involved in the biosorption process include chemisorption, complexation, surface and pore adsorption-complexation, ion exchange, microprecipitation, hydroxide condensation onto the biosurface, and surface adsorption. Chemical modification and spectroscopic studies have shown that cellular components including carboxyl, hydroxyl, sulfate, sulfhydryl, phosphate, amino, amide, imine, and imidazol moieties have metal binding properties and are therefore the functional groups in the biomass. Column studies using support matrices for biomass immobilization such as silica, agar, polyacrilamide, polysulfone, alginates, cellulase, and different cross-linking agents have been performed to improve the biomass adsorption capacity and reusability. In this review, the salient features of plant-derived materials are highlighted as potential phytofiltration sources in the recovery of toxic heavy and precious metals.
TL;DR: The macroscopic electro-optic activity of organic materials depends upon the mo- lecular hyperpolarizability, β, of individual organic chromophores and upon the product of number density, N, and noncentrosymmetric order,, of the chromophore in a hard- ened polymer lattice as mentioned in this paper.
Abstract: The macroscopic electro-optic activity of organic materials depends upon the mo- lecular hyperpolarizability, β, of individual organic chromophores and upon the product of number density, N, and noncentrosymmetric order, , of the chromophores in a hard- ened polymer lattice. Quantum and statistical mechanical calculations provide the basis for rational improvement of these parameters leading to electro-optic coefficients (at tele- communication wavelengths) of greater than 100 pm/V (a factor of 3 larger than values for the best inorganic material, lithium niobate). Such calculations also provide insight into what further improvements can be expected. Owing to low and relatively dispersionless dielectric constants and refractive indicies, organic materials facilitate the fabrication of devices with 3 dB operational bandwidths of greater than 100 GHz. Moreover, robust and low optical loss materials can be fabricated by design. An under-appreciated advantage of organic electro- optic materials is their processability, and a variety of stripline, cascaded prism and super- prism, and ring microresonator devices are readily fabricated. Conformal, flexible, and three- dimensional devices are also readily produced. With ring microresonator devices, active wavelength division multiplexing, optical network reconfiguration, and laser frequency tun- ing are straightforwardly accomplished.
TL;DR: This review will focus on immunological, nucleic acid, and cell-based clinical and biological sensors, with special emphasis on the approaches used for immobilization or biological reagents and low-cost electrochemical biosensors.
Abstract: Biochemical sensors have emerged as a dynamic technique for qualitative and quantitative analysis of different analytes in clinical diagnosis, environmental monitoring, and food and process control. The need for a low-cost, reliable, ultra-sensitive, and rapid sen- sor continues to grow as the complexity of application areas increases. New biosensing tech- niques are emerging due to the need for shorter sample preparation protocols. Such novel biosensor designs make field and bed-site clinical testing simpler with substantial decrease in costs per sample throughputs. In this paper, we will review the recent trends and challenges in clinical and environmental biosensors. The review will focus on immunological, nucleic acid, and cell-based clinical and biological sensors. Special emphasis will be placed on the approaches used for immobilization or biological reagents and low-cost electrochemical biosensors. The promising biosensors for rapid diagnosis of cancer or HIV are also dis- cussed.
TL;DR: The development of micellar carriers capable of releasing their drug load in response to small changes in pH by incorporating “titratable” groups such as amines and carboxylic acids into the copolymer backbone, thus altering the solubility of the polymer upon protonation and disrupting micelle formation is studied.
Abstract: In recent years, supramolecular micellar assemblies formed from amphiphilic block copolymers have been receiving attention as potential drug carriers. The size of the car- riers is ideal for avoiding rapid renal exclusion and reticuloendothelial uptake, and enables them to be targeted to certain tissues such as tumors. One important issue determining the ef- fectiveness of a micellar drug carrier is the ability to control the time over which drug release takes place, or to possibly trigger drug release at a specific location or time. The mildly acidic pH encountered in tumor and inflammatory tissues as well as in the endosomal and lyso- somal compartments of cells has inspired the development of micellar carriers capable of re- leasing their drug load in response to small changes in pH. One approach to the development of these systems has been to incorporate "titratable" groups such as amines and carboxylic acids into the copolymer backbone, thus altering the solubility of the polymer upon proto- nation and disrupting micelle formation. Another approach has been to incorporate acid- degradable linkages into the copolymer, either for direct attachment of the drug, or to cause a structural change of such magnitude that micellar integrity is lost and the drug is released.
TL;DR: Asymmetric 1,4-arylation and -alkenylation was achieved by use of organoboronic acids or their derivatives in the presence of a rhodium catalyst coordinated with binap or its related ligands.
Abstract: Asymmetric 1,4-arylation and -alkenylation was achieved by use of organoboronic acids or their derivatives in the presence of a rhodium catalyst coordinated with binap or its related ligands. The scope of this asymmetric addition is very broad, α,β-unsaturated ke- tones, esters, amides, 1-alkenylphosphonates, and 1-nitroalkenes being efficiently converted into the corresponding 1,4-addition products with over 95 % enantioselectivity. The catalytic cycle in water is proposed to involve three intermediates (aryl- or alkenyl-rhodium (oxa-π- allyl)rhodium, and hydroxo-rhodium) by NMR studies on the rhodium intermediates.
TL;DR: The mechanism of metal extraction is mainly chemistry-driven and is due to the action of a combination of ferric and hydrogen ions, depending on the type of mineral as discussed by the authors, which are produced by the activity of chemolithotrophic microorganisms that use either iron or sulfur as their energy source and grow in highly acidic conditions.
Abstract: Biomining is currently used successfully for the commercial-scale recovery of met- als such as copper, cobalt, and gold from their ores. The mechanism of metal extraction is mainly chemistry-driven and is due to the action of a combination of ferric and hydrogen ions, depending on the type of mineral. These ions are produced by the activity of chemolithotrophic microorganisms that use either iron or sulfur as their energy source and grow in highly acidic conditions. Therefore, metal extraction is a combination of chemistry and microbiology. The mixture of organisms present may vary between processes and is highly dependent on the temperature at which mineral oxidation takes place. In general, rel- atively low-efficiency dump and heap irrigation processes are used for base metal recovery, while the biooxidation of difficult-to-treat gold-bearing arsenopyrite concentrates is carried out in highly aerated stirred-tank reactors. Bioleaching reactions, the debate as to whether the reactions are direct or indirect, the role of microorganisms, and the types of processes by which metals are extracted from their ores are described. In addition, some new processes under development and the challenges that they present are discussed.
TL;DR: Several advances in the coordination chemistry of stable free-radical species over the past six years are documented in this paper, with an emphasis on enhanced magnetic or optical properties in these complexes.
Abstract: Several advances in the coordination chemistry of stable free-radical species over the past six years are documented in this review article. Specifically, a number of recent re- ports focused on the coordination chemistry of chelating nitroxide ligands are highlighted, with an emphasis on enhanced magnetic or optical properties in these complexes. Furthermore, very intriguing recent magnetic and optical studies with one-dimensional ni- troxide chain complexes (new "Glauber" chains and chiral magnets) are also discussed. The verdazyls are another family of stable radicals whose coordination chemistry was literally un- explored prior to 1997. A summary of recent reports discussing metal-verdazyl coordination complexes is also presented, followed by an eye to the future of stable radical design and the coordination chemistry of these interesting molecules.
TL;DR: Synthetic advances from laboratories for the construction of Biginelli libraries via solution-and solid-phase strategies that are amenable to a high-throughput or combinatorial format are summarized.
Abstract: With the emergence of high-throughput screening in the pharmaceutical industry over a decade ago, synthetic chemists were faced with the challenge of preparing large col- lections of molecules to satisfy the demand for new screening compounds. The unique ex- ploratory power of multicomponent reactions such as the Biginelli three-component reaction was soon recognized to be extremely valuable to produce compound libraries in a time- and cost-effective manner. The present review summarizes synthetic advances from our labora- tories for the construction of Biginelli libraries via solution- and solid-phase strategies that are amenable to a high-throughput or combinatorial format.
Journal Article•
TL;DR: An overview of methods for chemical speciation analysis of elements in samples of sediments and soils is presented in this article, where the sequential leaching procedure is thoroughly discussed, and examples of different applications are shown.
Abstract: This paper presents an overview of methods for chemical speciation analysis of elements in samples of sediments and soils. The sequential leaching procedure is thoroughly discussed, and examples of different applications are shown. Despite some drawbacks, the sequential extraction method can provide a valuable tool to distinguish among trace element fractions of different solubility related to mineralogical phases. The understanding of the speciation of trace elements in solid samples is still rather unsatisfactory because the appropriate techniques are only operationally defined. The essential importance of proper sampling protocols is highlighted, since the sampling error cannot be estimated and corrected by standards. The Community Bureau of Reference (BCR) protocols for sediment and soil give a good basis for most of the solid samples, and the results can be compared among different laboratories.
TL;DR: In this article, the bending and unbending were induced exactly along the polarization direction of in-cident linearly polarized light, and a single polydomain liquid-crystalline elastomer film could be bent repeatedly and precisely along any chosen direction.
Abstract: Liquid-crystalline gels and elastomers were prepared by polymerization of mix- tures containing azobenzene monomers and cross linkers with azobenzene moieties. Oriented liquid-crystalline gels and elastomer films were found to undergo anisotropic bending and unbending behavior only along the rubbing direction, when exposed to alternate irradiation of unpolarized UV and visible light. In the case of polydomain liquid-crystalline elastomer films, the bending and unbending were induced exactly along the polarization direction of in- cident linearly polarized light. By altering the polarization direction of light, a single film could be bent repeatedly and precisely along any chosen direction.
TL;DR: The enhanced toughness and reduced permeability of polymersomes makes them, therefore, very suitable as stable nanocontainers, which can be used, for example, as reactors or drug delivery vehicles.
Abstract: Amphiphilic block copolymers have the ability to assemble into multiple morphologies in solution. Depending on the length of the hydrophilic block, the morphology can vary from spherical micelles, rods, and vesicles to large compound micelles (LCMs). Vesicle formation is favored upon an increase in total molecular weight of the block copolymer, that is, an increasing bending modulus (K). Owing to the polymeric character of this type of vesicle (also called polymersomes), they possess remarkable properties. The diffusion of (polymeric) amphiphiles in these vesicles is very low compared to liposomes and for high-molecular-weight chain entanglements even lead to reptation-type motions, which make it possible to trap near-equilibrium and metastable morphologies. Additionally, in contrast to liposomes, membrane thicknesses can exceed 200 nm. As a consequence, this increased membrane thickness, in combination with the conformational freedom of the polymer chains, leads to a much lower permeability for water of block copolymer vesicles compared to liposomes. The enhanced toughness and reduced permeability of polymersomes makes them, therefore, very suitable as stable nanocontainers, which can be used, for example, as reactors or drug delivery vehicles.
TL;DR: This work summarizes recent developments in the study of the photodegradation mechanism of ketoprofen, fenofibric acid, and tiaprofenic acid and presents an analysis of excited-state electronic energy levels, the type of intermediates formed following excitation, and transient intermediate lifetimes.
Abstract: Toxic reactants are a common result of the interaction of sunlight with pharmaceu- tical agents transported in the blood system or applied topically. Over the past decade there has been a considerable amount of research toward understanding both the unimolecular de- activation pathway of photoexcited pharmaceutical products and their photosensitizing capa- bility in the presence of biological substrates. This work summarizes recent developments in the study of the photodegradation mechanism of ketoprofen, fenofibric acid, and tiaprofenic acid. An analysis of excited-state electronic energy levels, the type of intermediates formed following excitation, and transient intermediate lifetimes is presented. The analysis involves both parent drugs and their major photoproducts. Phototoxicity, usually the result of adverse photochemical reactions following direct photoexcitation of the drugs, is shown to be strongly related to the photoexcitation of photoproducts when high radiation dose conditions prevail. The photoproducts are the species directly involved in photosensitizing reactions.
TL;DR: In this paper, the authors present quantities, terminology, and symbols of terms related to photothermal phenomena and used in photothermal and related spectroscopies, including transient grating, transient lens, photoacoustic spectroscopy and photothermal radiometry.
Abstract: This paper presents quantities, terminology, and symbols of terms related to photothermal phenomena and used in photothermal and related spectroscopies. The terms used in the literature to describe photothermal phenomena and methods are reviewed, and a glossary of terms is given. The origins of photothermal phenomena, as well as the relations among various photothermal effects, are summarized. The listed terms cover the terminology in transient grating, transient lens, photoacoustic spectroscopy, photothermal radiometry, calorimetry, interferometry, deflection, reflection, and other related spectroscopies, which use or are related to photothermal effects.
TL;DR: In this article, the basic terms and definitions related to piezoelectric materials and sensing devices, electric transducers, and analytical measurements with PLS sensors are provided, and the more essential response equations are presented.
Abstract: Piezoelectric chemical and electrochemical sensors are classified. Basic terms and definitions related to piezoelectric materials and sensing devices, electric transducers, and analytical measurements with piezoelectric chemical sensors are provided. In addition, the more essential response equations are presented.
TL;DR: The glossary as discussed by the authors contains definitions of 365 terms frequently used in the multidisciplinary field of toxicokinetics, especially in relation to hazard and risk assessment, where medical terms are included, where relevant, because of their frequent occurrence in the toxicological literature and because chemists would not normally expect to be familiar with them.
Abstract: This glossary contains definitions of 365 terms frequently used in the multidisciplinary field of toxicokinetics. The glossary is compiled primarily for chemists who find themselves currently working in toxicology and requiring a knowledge of the expressions used in toxicokinetics,especially in relation to hazard and risk assessment. Some medical terms are included, where relevant, because of their frequent occurrence in the toxicological literature and because chemists would not normally be expected to be familiar with them. There are three annexes,one containing a list of abbreviations and acronyms used in toxicokinetics, one containing a list of abbreviations and acronyms of names of international bodies and legislation that are relevant to toxicology and chemical safety, and one giving sources for further reading.