Comment on "Adsorption of naphthalene on zeolite from aqueous solution" by C.F. Chang, C.Y. Chang, K.H. Chen, W.T. Tsai, J.L. Shie, Y.H. Chen

A paper contributes not only by its originality and creativity, but also by its continuity and development toward subsequent research. Referencing and quotation accuracy are an important part of a scientific article. This study presents a literature review concerning the precision of 50 first authors' publications, which originally cited Ho's pseudo-second-order kinetic expression paper in kinetics model for solute sorption on various sorbents. This model applies to a range of solid-liquid systems such as metal ions, dyestuffs, herbicides, oil, and organic substances in aqueous systems onto various sorbents. In addition, citations of Lagergren and Elovich rate equations are also discussed. This comment offers information for citing the original idea of Ho's pseudo-second-order kinetic expression and Lagergren's pseudo-first-order kinetic equation. It is also suggested that the cited paper should be accurately quoted.     

Etude thermoanalytique de substances psychotherapeutiques. II. Substances antipsychotiques. Chlorprothixene,chlorhydrate de chlorpromazine,chlorhydrate de levomepromazine,dichlorhydrate de fluphenazine

The thermoanalytical study of chlorprothixene (a), chlorpromazine hydrochloride (b), levomepromazine hydrochloride (c), and fluphenazine hydrochloride (d), has enabled the existence of polymorphs for (b) and (d) to be shown. The thermal stability and decomposition kinetics of commercial forms of the drugs have been determined. The thermal behaviour of (c) and (d) does not permit their study by transparency method nor the determination of their degree of purity by differential scanning calorimetry. The temperatures and intervals of fusion are given for (a) and (b). Knowing the thermal behaviour, the degree of purity: 99.47 ± 0.11% (a), 99.61 ± 0.20% (b); enthalpy: 27.82 ± 1.05 (a), 28.42 ± 0.57 (b) kJ mole^?1; and entropy of fusion have been evaluated by differential scanning calorimetry.     

D. Purves,trace-element contamination of the environment : Elsevier,Amsterdam, 1977, xi + 260 pp., price Dfl. 85, U.S. $34.75

A study of the dissolution rate of magnetite electrodes required a reasonably precise method for the determination of iron in aqueous solutions containing 1 mol kg^-1 sodium perchlorate. Atomic absorption spectrometry with electrothermal atomization in the wavelength range 248–392 nm with ashing at 1600°C proved to be the most satisfactory method. Iron concentrations in the range 0.1–100 μg ml^-1 were determined with 1-μl samples. The addition of low flow rates of acetylene to the nitrogen purge gas improved the reproducibility and increased the carbon rod lifetime.     

SMART: A data reporting standard for mass spectrometry imaging By Ying Xi,Alexandria L. Sohn,Alena N. Joignant,Stephanie M. Cologna,Boone M. Prentice and David C. Muddiman

Mass spectrometry imaging (MSI) is an important analytical technique that simultaneously reports the spatial location and abundance of detected ions in biological, chemical, clinical, and pharmaceutical studies. As MSI grows in popularity, it has become evident that data reporting varies among different research groups and between techniques. The lack of consistency in data reporting inherently creates additional challenges in comparing intra- and inter-laboratory MSI data. In this tutorial, we propose a unified data reporting system, SMART, based on the common features shared between techniques. While there are limitations to any reporting system, SMART was decided upon after significant discussion to more easily understand and benchmark MSI data. SMART is not intended to be comprehensive but rather capture essential baseline information for a given MSI study; this could be within a study (e.g., effect of spot size on the measured ion signals) or between two studies (e.g., different MSI platform technologies applied to the same tissue type). This tutorial does not attempt to address the confidence with which annotations are made nor does it deny the importance of other parameters that are not included in the current SMART format. Ultimately, the goal of this tutorial is to discuss the necessity of establishing a uniform reporting system to communicate MSI data in publications and presentations in a simple format to readily interpret the parameters and baseline outcomes of the data.     

Singlet oxygen and polymer photooxidations. I. Sensitizers,quenchers, and reactants

A study designed to ascertain the role of singlet molecular oxygen in the photodegradation of plastics established that most classes of dye chromophores are sensitizers in polymer films, absorbing light and transferring the absorbed energy to ambient triplet ground state molecular oxygen, generating metastable reactive singlet molecular oxygen. Unsaturated polymers containing polybutadiene, polyisoprene, etc. are highly reactive to singlet oxygen produced through photosensitization, generating hydroxylic and carbonyl derivatives and losing their rubbery properties as consequences of such reactions. Many types of transition metal chelates are singlet oxygen quenchers. The relationships of the structures and spectroscopic properties of these chelates to their efficiency in quenching singlet oxygen are examined and discussed.     

13C n.m.r. spectra of N,N-dialkylamides

Carbon-13 n.m.r. spectra of formic, acetic, propionic and butyric acid amides with N,N-di-n-alkyl substituents have been completely assigned with the aid of extensive double resonance experiments. The data obtained were used to study long range steric effects on chemical and solvent shifts.     

Small-angle light scattering from hedrites,ovoids, and spiral ovoids. II. Experimental

Procedures for obtaining hedrites, ovoids, and spiral ovoids in polyoxymethylene are described. Results of morphological studies on these structures by optical and electron microscopy are presented. Small-angle light scattering studies on single isolated supermolecular structures are described. The V_v and H_v diffraction patterns obtained experimentally are discussed in the light of theoretical results of Part I of this study.     

Etude thermoanalytique de substances psychotherapeutiques. I. Anxiolytiques. Phenprobamate,meprobamate, clobazam et medazepam

The thermoanalytical study of phenprobamate (a), meprobamate I (b), clobazam (c), medazepam I (d) has enabled the existence of polymorphs for (d) to be established, and to confirm that of (b). The thermal stability and decomposition kinetics of commercial forms of drugs have been determined; their temperatures and intervals of fusion are given. Knowing the thermal behaviour of these compounds, their degree of purity: 99.67±0.19% (a), 99.32± 0.04% (b), 99.61±0.07% (c), 99.66±0.14% (d); their enthalpy, 27.58±0.69 (a), 34.23±1.22 (b), 30.38±0.81 (c), 21.48±0.75 kJ mole^-1; and entropy of fusion have been evaluated by differential scanning calorimetry.     

Comment on "HCl adsorption on ice at low temperature: a combined X-ray absorption, photoemission and infrared study" by P. Parent, J. Lasne, G. Marcotte and C. Laffon, Phys. Chem. Chem. Phys., 2011, 13, 7142

On the basis of NEXAFS, photoemission and FTIR spectra of ice films with low doses of adsorbed HCl, the authors of the PCCP paper "HCl adsorption on ice at low temperature: a combined X-ray absorption, photoemission and infrared study", Phys. Chem. Chem. Phys., 2011, 13, 7142, have come to conclusions regarding the behavior of submonolayer amounts of HCl at 50 K that contradict published results of the authors of this Comment. Our purpose is to argue that the conclusion, attributed going forward to PLML (authors' initials), that nearly 100% of HCl ionizes for dosage levels near to 0.16 monolayer (ML) or 0.3 Langmuir (L) at 50 K is questionable. Rather, we reaffirm our conclusions of much lower levels of ionization for similar temperatures and HCl dosages based on reactive ion scattering (RIS) and low energy sputtering (LES) data for ice films and FTIR spectra of ice nanocrystals. A second current paper by Ayotte et al., J. Phys. Chem. A, 2011, 115, 6002, that largely parallels in method and results the RAIR spectroscopy of PLML, is also given special notice.     

The Physical Chemistry of Membranes : M.E. Starzak. Academic Press,Orlando, 1984, x + 334 pp., US$47.00. Equations of Membrane Biophys. N. Lakshminarayanaiah,Academic Press,Orlando, 1984, x + 426 pp., £53.50

Changes in the adsorption profiles of 1,4-naphthohydroquinone (NHQ) on smooth polycrystalline platinum electrodes in aqueous 1 M HClO₄ brought about by varying levels of surface-active organic impurities [typified by hydroquinone (HQ) and benzene] have been studied by thin-layer electrochemical techniques, 10^?5M HQ is sufficient to alter the adsorption profile of NHQ; above 10^?4M HQ, the packing density transitions prominent from pure NHQ solutions were completely suppressed. Similar results were obtained when benzene was used as the contaminant. Packing density measurements indicated that the subject surface-active impurities inhibited formation of flat-, but not edge-, adsorbed NHQ; this is in agreement with data from a previous study [M.P. Soriaga, J.H. White, D. Song and A.T. Hubbard, J. Electroanal. Chem., 171 (1984) 359] which showed that low-levels of iodide, a surface-active anion, enforced formation of edge-adsorbed NHQ even at (low) concentrations where flat-adsrobed species would have formed from pure NHQ solutions. The presence of surface-active impurities may help account for the profound differences in adsorption measurements reported in the literature for various aromatic compounds.     

Carbon-13 nuclear magnetic resonance for organic chemists | George C. Levy and Gordon L. Nelson,Wiley-Interscience,New York, 1966, pp. xiii + 222, price 4.50

A Lagrange multipliers method is shown to be a convenient way of applying constraints to a Newton-Raphson minimization algorithm in a conformational analysis program. To illustrate this method two applications are dealt with in some detail. The Eckart conditions are used as a set of constraints to avoid mathematical difficulties associated with the empirical valence-force potential in a conformational analysis problem. For the molecules considered the use of constraints speeds up the Convergence. The second application illustrates how the method can be used to study selected sections through potential energy surfaces.     

Comment on "An alternative Avrami equation to evaluate kinetic parameters of the interaction of Hg(II) with thin chitosan membranes," by E.C.N. Lopes, F.S.C. dos Anjos, E.F.S. Vieira, and A.R. Cestari

A history of using and applying Ho's pseudo-second-order kinetic expression for adsorption systems is presented. A reference section in a paper is important to researchers interested in the paper's statement and in following the study or finding useful information from the paper. This section is as important as the core of a paper. This comment offers information on citing the original idea of pseudo-second-order kinetic expression.     

Die sterischen Bedingungen der Fragmentierungsreaktion III. Teil. Stereoisomere 4-, 5- und 7-Decahydrochinolyl-toluolsulfonate Fragmentierungsreaktionen, 16. Mitteilung

In a heterolytic fragmentation reaction of the type a-b-c-d-X → a - b + c = d + : X the geometry of the d - X bond and that of the electron-donating group a relative to the b - c bond are critical. This follows from a study of solvolysis rates and products of stereoisomeric 1-methyl-4-, -5- and -7-decahydroquinolyl p-toluenesulphonates in 80 Vol.% ethanol.     

High temperature crystallization of aluminum fluoride. Course,hydrolysis, solid phases.

A study for AlF₃ crystallization from water solution was performed in the temperature range 100 to 200°C.Four solid phases were found to be precipitated, AlF₃.3H₂O (up to ca.120°C, cubic α-AlF₃.H₂O (decomposition of AlF₃.3H₂O in suspension), hexagonal β -AlF₃.H₂O (direct from solution) and the hydroxyfluoride Al(OH,F)₃.H₂O with an F/Al ratio of ca. 2.5 (hydrolysis of AlF₃). The extent of hydrolysis was established as a function of the initial AlF₃ concentration.X-ray diffraction and thermogravimetric data for the monohydrates were given and differences between the two indicated.     

Computational advances in organic chemistry: Molecular structure and reactivity. Edited by C. Ögretir and I. G. Csizmadia,NATO ASI Series C,Vol, 330.

We here report an AM 1 study for the reaction of different types of radicals with the acetone enolate ion 1 and other ambident nucleophiles. The theoretical reactivity order determined is phenyl > methyl > tert-butyl ? bicyclo-[2.2.1]hept-1-yl. The activation energy for the coupling of aliphatic radicals is ascribed mainly to nonbonded interactions. Considering possible solvent effects, we propose the same order of reactivity in solution. The coupling reaction of phenyl radical with 1 is an exothermic process with nonactivation energy in the gas phase. Any energy barrier in solution is here ascribed to desolvation of the anion. The regiochemistry of the coupling of radicals with ambident nucleophiles such as 1 , phenoxide, or phenylamide anions is also explained on a theoretical basis. © 1992 John Wiley & Sons, Inc.     

Cardenolides and coumarins ofCoronilla varia, C. cretica, etc.

Conclusions The cardenolide and coumarin composition ofC. varia L. and the closely related speciesC. hyrcana Pril.,C. cretica L., andC. orientalis Müll have been investigated. It has been shown that they all contain the cardiac glycoside hyrcanoside, with the exception ofC. orientalis, in which another, unidentified, glycoside, has also been found.A comparative study of some properties of hyrcanogenin (⁴-strophanthidin) and pachygenin (⁵-strophanthidin) connected with conformational features has been carried out.In the species studied, no less than five coumarins have been found of which umbelliferone, scopoletin, and daphnoretin have been isolated.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 3, pp. 141–144, 1969     

The S.M.A.R.T. (small mass,affordable, rapid,transfer-less) digestion method for heavy metal determinations

The S.M.A.R.T. (small mass, affordable, rapid, transfer-less) digestion method was developed to determine heavy metal concentrations in small sample masses. The S.M.A.R.T. digestion method is a hot water bath digestion where sample digestion and dilution are performed in the original sample tube. This method is faster than the typical methods used and reduces potential sources of error. Masses as small as 0.01 g have been digested and analysed using this method. The preparation and digestion time is reduced from 10 h to less than 4 h. Acid volumes are reduced from millilitres to microlitres and the only disposable supplies needed are sample tubes and pipette tips. Method accuracy was determined by digesting seven replicates of two standard reference materials using the S.M.A.R.T. method and analysing samples by inductively coupled plasma mass spectrometry. The S.M.A.R.T. digestion method was found to provide excellent recoveries for Al (76 ± 2.7%), Mn (99 ± 11%), Co (92 ± 17%), Ni (93 ± 28%), Cu (109 ± 33%), Zn (97 ± 7.1%), As (108 ± 20%), Sr (90 ± 12%), Mo (84 ± 23%), Ag (91 ± 1.8%), Cd (95 ± 6.2%), Sn (139 ± 52%) and Pb (95 ± 22%). This study has successfully developed an efficient and reproducible digestion method for heavy metal determination in limited biomass samples.     

4,5-naphthocycloheptatrienyliden. - Reaktionen,selektivität,multiplizität

For the first time it has been possible to study reactions, selectivity and multiplicity of a benzoannulated tropylidene like $\text{1}$.     

Structure, magnetizability, and nuclear magnetic shielding tensors of bis-heteropentalenes. IV. Dihydrophospholophosphole isomers

The geometry of the heteropentalenes formed by two phosphole units has been determined at the DFT level. The magnetic susceptibility and the nuclear magnetic shielding at the nuclei of these systems have also been calculated using gauge-including atomic orbitals and a large Gaussian basis set to achieve near Hartree-Fock estimates. A comparative study of the various isomers, of their flattened analogs, and of the parent phosphole molecule, shows that the [3,4-c] isomer is the most aromatic system in the set considered, assuming diatropicity and degree of planarity as indicators, even if it is the less stable in terms of total molecular energy. Plots of magnetic field-induced current densities confirm diatropicity of P-containing bis-heteropentalenenes, showing, however, significant differences from the analogous systems with distinct heteroatoms. The maps give evidence of spiral flow nearby C-C bonds, compatible with prevalent distortive behavior of pi electrons exalted by pyramidalization at P, and competing against the sigma electron compression, which would favor planar structure.