bluuebunny/crossref_metadata_2025_split huggingface dataset:
How do they do it?—Making oxygen
Authors: Milgrom Lionel R 
Published: November 2023

Abstract
Why is grass green and blood red? Put another way, why is chlorophyll photoactive, beginning the process of photosynthesis, while the closely related heme performs a whole range of transport and redox functions that are non-photochemical in origin and depend on the protein that it is embedded in? To begin to answer these questions we need to know something about the chemical and physical properties of porphyrins. To understand those properties, we will require a knowledge of porphyrin electronic structure. That electronic structure is based on a skeleton of 20 carbon atoms surrounding a central core of four nitrogen atoms. This atomic arrangement supports a highly stable configuration of single and double bonds, called an aromatic 1r-system. The simplest and, indeed, archetypal aromatic 1r-system is seen in benzene.
What happens when it all goes wrong?
Authors: Milgrom Lionel R 
Published: November 2023

Abstract
We have seen how porphyrins arc biosynthesised and, in the last chapter, how they are metabolised. In any normally functioning living system, these processes are usually held in balance, so that a steady-state concentration of any particular substance is obtained. But mistakes do occur and when they do, they lead to a variety of pathological conditions. In this chapter, we shall be examining some of these. We shall also look briefly at what happens when the protein (in particular globin) that surrounds a porphyrin, malfunctions due to genetic misprogramming and does not provide the correct working environment for the heme moiety.
Werner clathrates: guest-lattice intermolecular interactions
Authors: Lipkowski Janusz 
Published: November 2023

Abstract
The ‘clathratogenic’ ability of coordination complexes of the general formula M(Il)XzA4 was first reported by Schaeffer and coworkers [WD. Schaeffer et al., J. Am. Chem. Soc., 79(1957), 5870). During 1950-1970 the main reason for studying the subject was the possibility of practical use of clathration selectivity in separation of mixtures which are otherwise separable with difficulty, i.e. mixtures of isomeric compounds. Thus, the early literature contains extensive information on selectivity of clathration of a variety of mixtures of organic compounds (guests) by different Werner complexes (host) {Tobie 1}.
ISIS: a powerful new tool for organic crystal chemistry
Authors: Finney J L , Wilson C C 
Published: November 2023

Abstract
Crystallographic methods to solve crystal and molecular structures are central to organic crystal chemistry. X-rays havegenerally been the preferred probe for crystallographic work due to the wide availability and convenience of laboratory X-ray sources. Most of the structural work to date has been performed on single crystals, which have been capable of giving data of much higher quality than powder (polycrystalline) materials. Also important in this field are spectroscopic methods, which can be used to improve our understanding of the interactions between molecules. In spectroscopy, infrared and Raman, along with NMR, have been extensively exploited.
New developments on the Enraf-Nonius FAST detector
Authors: Schierbeek B 
Published: November 2023

Abstract
The Enraf-Nonius FAST system (Arndt & Gilmore, 1979) consists of a TV-camera based detector, combined with a four circle goniometer with kappa type geometry and interfaced to a microVAX computer and a TV monitor. The goniometer is the well known CAD4 kappa goniometer, which allows the user flexible control over orientation : no remounting of the crystal, easy alignment of the crystal and efficient covering of reciprocal space, which has high precision and furthermore an open design with minimum obscuration, allowing /-N2 cooling, shock freezing and the possibility to collect full absorption profiles.
Statistical descriptors
Authors: Schwarzenbach D 
Published: November 2023

Abstract
Many crystallographers are aware that estimated standard deviations (e.s.d.’s) of structural parameters routinely calculated by current least-squares refinement programs are unrealistic (a fitting acronym would be u.s.d.’s) and that the actual uncertainties are larger, and sometimes much larger (Taylor & Kennard, 1986). There are two types of reasons for this fact: The models used for calculating the observed quantities (in general diffraction data) are invariably deficient. The model includes all operations leading from the raw data to the final structural parameters: data reduction procedures used to calculate observed structure amplitudes are as much part of the model as is the structure factor expression used in the structure refinement. Even if some of the deficiencies of the standard structural model are well-known in principle (viz. aspherical charge density distributions, anharmonic vibrations, effects of disorder, angular dependence of anomalous dispersion, extinction, thermal diffuse scattering, scan truncation), their combined effect is difficult to assess. Model deficiencies are generally known as systematic errors.
Macromolecular crystallographic computing designed around the XTAL system
Authors: Watenpaugh K D , Holland D R , Collins, D M , Stewart J M 
Published: November 2023

Abstract
The XTAL System (Hall & Stewart, 1989) has been designed to be a highly portable, highly integrated system of programs that centers around a flexible data file concept allowing for efficient archiving of data. The master file contains all the crystallographic data, atomic coordinates, and auxiliary information necessary to carry most desired calculations with a minimum of user control input. On the other hand, the routines contain a large array of options to allow the experienced and expert crystallographer considerable flexibility in the calculations they may wish to perform or the paths by which they may wish to carry out structure determinations. Besides the archival data file, the XTAL System has a free formal control input based on the use of keywords requiring input information only when normally used defaults are to be altered. This overall philosophy has allowed for the successful implementation of an integrated system of programs not only for small molecule crystallography, but also for macromolecular crystallography. This integration provides not only for the use of routines commonly used by both groups of users (e.g. Fourier or structure factor calculating programs), but also, for those routines considered to be in one or the other domain (e.g. direct methods for small molecule studies). Finally the routines included in the system have been extensively documented both in the source codes and in the manuals, a practice that is too easily overlooked by many program developers. Detailed description of the system, users manuals, program development manuals and the distribution tape can be obtained from S. R. Hall at the Crystallography Centre, University of Western Australia, Nedlands. Questions regarding the XTAL system’s use in macromolecular calculations and problems should be addressed to K. D. Watenpaugh.
The MAD phasing method in macromolecular crystallography: general principles and the problem of the anisotropy of anomalous scattering
Authors: Fanchon E , Hendrickson W A 
Published: November 2023

Abstract
Several macromolecular structures have been solved with the Multiplewavelength Anomalous Diffraction (MAD) method in the recent years (Kahn et al. 1985, Korszun 1987, Krishna Murthy et al., 1988, Guss et al., 1988, Hendrickson et al. 1988, Hendrickson, Pahler et al. 1989, Graves et al., 1990). These successes have been made possible by the availability of tunable X-ray sources, the development of efficient area detectors and by advances in the methods for analysis of MAD data. Now the instrumentation is in place to make highly accurate measurements on macromolecular crystals so as to exploit the anomalous signal in direct phase determination. In this contribution we describe briefly the theoretical basis, experimental requirements and computational implementation of the MAD method (a more detailed review can be found in Fourme Hendrickson, 1990). In the last part we treat a problem specific to MAD, namely the effect of the anisotropy of anomalous scattering on the phase determination.
The phase problem in protein crystallography: integration of multiwavelength anomalous diffraction and direct methods
Authors: Krabbendam H 
Published: November 2023

Abstract
Direct methods have found a successful application in the solution of the phase problem in diffraction techniques, when applied to small-molecule structures. The method depends heavily on probability relations for three-phase structure invariants and, to a lesser extent, on relations for four-phase invariants. However, the probability relations break down if the number of atoms in the unit cell becomes large, as for macromolecular structures. Attempts to extend the range of classical direct methods to small protein structures have had some success (Woolfson & Yao Jia-xing [1988]); but for a systematic application to large-size structures a more fundamental revision of the methods, notably the maximum entropy methods (Bricogne [1984],[ 1988], Bricogne & Gilmore [1990], Gilmore, Bricogne & Bannister [1990]), seems to be called for.
What are the alternatives?
Authors: Baggott Jim 
Published: November 2023

Abstract
So, where do we go from here? It is apparent from the last chapter that nature denies us the easy way out. We can rule out the idea of local hidden variables, one of the simpler solutions to the conceptual problems of quantum theory. Yet the Copenhagen interpretation is regarded by some to be no interpretation at all. Even those who adhere to the Copenhagen view tend to put aside or disregard the conceptual difficulties that it raises as they analyse the results from the latest particle accelerator experiment. This is not a very satisfactory situation.
Silicon based non-oxide ceramics
Authors: Trigg* M B , Murray M J 
Published: November 2023

Abstract
Silicon based non-oxide ceramics such as silicon carbide and silicon nitride are an emerging new class of engineering materials. At the present time, a major barrier to the widespread utilization of these materials is the high cost of both powders and products. Work currently under way within the CSIRO Division of Materials Science and Technology is aimed at identifying low cost routes for the production of both powders and product.
Organotin and organosilicon compounds in cross-coupling, aromatic nucleophilic substitution, and addition reactions
Authors: Beletskaya I P 
Published: November 2023

Abstract
Abstract
The reactions of organotin compounds with organic halides and acid halides catalysed by palladium complexes without phosphine ligands have been carried out under very mild conditions. These reactions afford biaryls, tolans, styrenes, dienes, and unsymmetrical ketones having various substituents. The synthesis of organotin compounds may be realized through the reactions of organic halides with hexaaryldistannanes catalysed by palladium and nickel complexes. The palladium-catalysed carbonylation of organic halides in the presence of organotin compounds of the series Alk SnNu (Nu= R, MeO, PhS, Et N, SnAik ) has proved to be a convenient method for the synthesis of ketones, derivatives of aromatic acids and o:-diketones.
Some features of tin solid state chemistry
Authors: Hagenmuller Paul 
Published: November 2023

Abstract
Three aspects of the solid state chemistry of tin are discussed. The first deals with the possibility of replacing 0 by F in Sn0 to give rise to low-mobility electrons in the conduction band. Electronic conductivity and IR reflectivity are enhanced without loss of transparency in the visible; applications to solar energy conversion are considered. The use of Sn Mossbauer spectroscopy is described in the second section to show that the technique is able to give quantitative information about bond covalency as well as the symmetry of the Sn(II) and Sn(IV) environments; mixed fluorides have been selected as a relevant example. The last section is devoted to F- conductivity of Sn(II) or Sn(IV) fluorides and a practical application to low-temperature oxygen pressure measurements is described.
Purification of GSH-S-transferase from Plutella xylostella larvae and its inhibition by organotin compounds
Authors: Balabaskaran S , Devi P Uma , Seow, S C , Das V G Kumar 
Published: November 2023

Abstract
Glutathione-S-transferases have been detected in the insecticide-resistant and susceptible strains of the larvae of Piute/la xylostella, a major pest of cruciferous vegetables. Although there was no significant difference in the enzyme-substrate affinities (Km) for glutathione (GSH) and 1-chloro- 2,4-dinitrobenzene (CDNB), the enzyme was present in almost five-fold excess in the resistant strain than in the susceptible strain. The enzyme in the crude supernatant suffered a marked loss in activity on standing; its activity, however, could be stabilized by thiol reagents such as 2-mercaptoethanol, cysteine or GSH, but not with metal ions.
Biological silicas, a study in organization
Authors: Perry Carole C 
Published: November 2023

Abstract
Silicas are found as biomineralized components of a variety of organisms (sponges, limpet teeth, stinging nettle hairs, diatoms). The biogenic silicas are composed of essentially monodisperse particles ranging from 2-15 nm in diameter depending on the structure. Such materials, however, show a range of extremely regular, sophisticated microscopic structures (fibrils, tubules, sheets). The extremely uniform particle sizes observed in these biogenic silicas, together with their complex but regular geometries, indicate a substantial degree of control over both polymerization and particle aggregation. This article provides information about microscopic and macroscopic structural order, aggregate surface chemistry, and addresses the question of the nature of the chemical and biological controls involved in precipitation. The direct result of our studies involving a wide range of structural, analytical, and biochemical techniques is the development of model systems for the investigation of silica particle formation from aqueous solutions, a situation found in both biological and industrial silica production.
Aromatic functionalized polyorganosiloxanes: synthesis, characterization, and application to gas separations
Authors: Reddy S R , Brisdon B J , Ashworth A J , England R , Zafar I 
Published: November 2023

Abstract
Membranes prepared from (co)polymers can be tailored to suit a given mass-separation task, and separations that are difficult using conventional procedures can be handled by employing membranes having selective side-chain functional groups. Although polydimethylsiloxane (PDMS) membranes have been found to be 10 times more permeable than commercially available polycelluloseacetate, their low selectivity for gas separations severely limits their commercial applications. ,2
Hydrolysis of polydimethylsiloxane monolayers on water surfaces
Authors: Rudoy V M 
Published: November 2023

Abstract
Studies of the chemical reactions of natural and synthetic polymers in surface layers are of considerable theoretical and applied interest. This is the case with polyorganosiloxanes which are often used as monolayers and thin films on liquid and solid surfaces. Although polydimethylsiloxane (PDMS) monolayers have been investigated by a number of workers, studies on the effect of the pH of the substrate on its properties have been limited only to oligomeric PDMS. The hydrolytic stability of the monolayers of high-molecular weight polydimethylsiloxanes has been studied in this present work.
Electrochemistry of triphenyltin acetate at a mercury-filmed glassy carbon electrode
Authors: Pascuat Cherrie Bunag , Vicente-Beckett Victoria A 
Published: November 2023

Abstract
The electrochemical behaviour of triphenyltin acetate was investigated by cyclicvoltammetry, differential pulse voltammetry, and controlled potential electrolysis at a mercury-filmed glassy carbon electrode. Effects on the electrochemical response of supporting electrolyte composition, pH, electrode rotation speed, and triphenyltin acetate concentration were determined.
The origins of physical chemistry
Authors: Laidler Keith J 
Published: November 2023

Abstract
It is sometimes said that the year of birth of physical chemistry was 1887. In that year there were indeed several important events relating to the subject, one being the launching of the Zeitschrifi far physikalische Chemie,the first journal devoted exclusively to physical chemistry. That year also saw, in the first volume of the Zeitschnfi,Svante Arrhenius’s famous paper on electrolytic dissociation, and one of van’t Hoff’s more important papers on the thermodynamics of solutions, work that was later to win him the Nobel Prize for chemistry in the first year that the prizes were awarded. Towards the end of the nineteenth century there was certainly something of a change in attitude towards physical chemistry, which then began to be recognized as a distinct branch of chemistry. However, a good deal of physical chemistry had been done previously. For example, two centuries earlier Robert Boyle had been carrying out physicochemical investigations, and a good case can be made for regarding him as the first physical chemist. His approach to chemistry is well described by his own statement that he hoped ‘to beget a good understanding ‘twixt the chymists and the philosophers’.
Boltzmann’s Kinetic Equation
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan 
Published: November 2023

Abstract
The state of a classical fluid of arbitrary density composed of N spherically symmetric atoms is characterized by a set of n -particle distribution functions fn(c1,,cn,r1,,rn,t), n = 1,× N, where r1, ×,rn and c1, × ,cn are the positions and velocities of the n particles. The lower the density, the smaller is the maximum number n required in order to describe the state of the gas with sufficient accuracy. We shall adopt the notational convention that no subscripts will be attached to the single-particle distribution function so that, accordingly, two-particle distribution functions will have the second particle labelled by a subscript ‘l ‘. For the so-called dilute gas regime, which in practice may extend over a pressure range from 10 to 10 Pa, a description of the state of the gas by means of the single-particle distribution f (c, r, t) is sufficient.
Field-Free Transport Properties
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan 
Published: November 2023

Abstract
With the obvious exception of the volume viscosity, which is new, and the thermal conductivity, which involves the transport both of internal and trans lational energy, the transport properties of molecular gases behave much like those for monatomic gases as functions of temperature and, for mixtures, composition. The experimental techniques for their measurement are well known, and extensive critical surveys of most data exist. For these reasons, we shall restrict our detailed discussion to those phenomena for which the molecular character is an important feature: thus, we shall treat the thermal conductivity and the volume viscosity in greater detail than the shear viscosity, diffusion and the mixture cross effects. In any case, we shall present relevant formulae for all transport phenomena and comment upon their uses and interpretation.
Anomalous Field-Effects
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan 
Published: November 2023

Abstract
The influence of either a magnetic or an electric field on transport properties of gases is based upon its effect upon the molecular angular momentum, which is no longer constant during free-flight motion between successive collisions; only its component along the field direction does not change. Previous chapters have been concerned essentially with rotational angular momentum alone (i.e. with diamagnetic molecules) and with linear Zeeman and Stark interactions. In the present chapter, we shall consider magnetic field-effects on the transport properties of gases of paramagnetic molecules possessing non-vanishing spin and/or electronic orbital angular momentum. In addition, we shall discuss anomalous behaviour of magnetic field-effects associated with molecules possessing a net nuclear spin angular momentum. Finally, we shall consider electric field-effects in gases of polar molecules which exhibit a transition from a quadratic Stark effect at low field strengths to a linear Stark effect at higher field strengths.
Observable Nonequilibrium Polarizations
Authors: Mccourt Frederick R W , Beenakker Jan J M , Köhler Walter E , Kuščer Ivan 
Published: November 2023

Abstract
In the two previous chapters, we have considered contributions of nonequilibrium polarizations to the transport properties. Such contributions may be thought of as indirect insofar as they constitute only a small portion of the total phenomenon. There are, however, also phenomena in which nonequilibrium polarizations can be observed directly. To do this, we must seek polarizations that give rise to macroscopically-observable alignment phenomena. From what we know about polarization contributions to transport phenomena, we may expect that such alignment phenomena will be rather weak.
Binary systems, partial miscibility in the liquid phase, and supercritical phenomena
Authors: Koningsveld R , Stockmayer W H , Nies E 
Published: November 2023

Abstract
So far, we have considered the components 1 and 2 to be completely miscible in all proportions in the liquid phase. The vapour phase was considered ideal in (69)—(81), but it was pointed out that the occurrence of a liquid/vapour critical point, as well as the curvatures of liquid/vapour equilibrium curves, show that those relations are not general.
Binary systems, solid solutions, and compounds
Authors: Koningsveld R , Stockmayer W H , Nies E 
Published: November 2023

Abstract
If a crystal lattice allows exchange of components, solid solutions will occur. In an extreme case, replacement is possible in any proportion and the solid solution might be close to ideal in the sense of (53). If ideal solutions obtain in both solid and liquid phases, the equilibrium relations are easily derived (Exercise 1). Examples of complete miscibility in the solid state exist, e.g., the systems Cu/Ni and Ge/Si.
The influence of pressure
Authors: Koningsveld R , Stockmayer W H , Nies E 
Published: November 2023

Abstract
Knowledge of the influence of pressure on phase relations in polymeric systems is needed in a number of practical instances. Polymerization processes in solution and in bulk applying elevated pressures are in technical use. We may mention the solution processes for the production of polyethylene, so-called linear low-density polyethylene (copolymers of ethylene and short-chain 1-alkenes such as 1-butene or 1-hexene), and elastomeric copolymers of ethylene and propylene, that take place in walkane mixtures, usually with the average composition of w-hexane. High pressures are applied in the production of low-density (long- and short-chain branched) polyethylene and copolymers like poly(ethylene-co-vinylacetate) in supercritical bulk ethylene.