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In the present study, novel spiro derivatives of α-santonin were prepared and tested for their anticancer activity against a panel of six human cancer cell lines. Spiro-isoxazoline and spiro-isoxazolidine derivatives have been generated on C-ring of α-santonin (α-methylene-γ-butyrolactone) by the 1,3-dipolar cycloaddition of α-santonin derivative 6 with nitrile oxides 7 and nitrones 9 respectively. Among all, compound 10b″ had shown IC50 of 0.01, 0.5 and 0.3 μM against PC-3, THP-1 and MCF-7 cell lines respectively. Further, flow cytometry studies showed that PC-3 cells treated with the spiro-isoxazolidine derivative 10b″ were arrested in the sub G1 phase of the cell cycle in a concentration dependent manner. The spiro-isoxazolidine derivative 10b″ also showed concentration dependent inhibitory activity against NF-κB, p65 with 57% inhibition in 24 h at 10 μM.

The pyrazine bridged dicobaloxime complexes [RCo(dSPhgH)2]2-μ-Pz [R = Et, Bu, CH2Ph] (1–3) with bis(thiophenyl)glyoxime, (dSPhgH2) have been synthesized and characterized by NMR spectroscopy for the first time. The X-ray structures of 2 and 3 are also reported. A cyclic voltammetry study shows the two cobalt centers are reduced and oxidized at different potentials as two discrete units. Molecular oxygen insertion into the Co–C bond in the complexes 1 and 3 under photochemical conditions leads to formation of [RCH2(O2)Co(dSPhgH)2]2-μ-Pz [R = CH3, Ph]. Careful monitoring of the reaction by 1H NMR reveals formation of a mixture of products RCH2(O2)Co(dSPhgH)2-Pz-Co(dSPhgH)2CH2R and [RCH2(O2)Co(dSPhgH)2]2-μ-Pz [R = CH3, Ph] at the initial stage of the reaction corresponding to mono and bis insertion. The ratio of these products changes with time and finally [RCH2(O2)Co(dSPhgH)2]2-μ-Pz [R = CH3, Ph] was isolated as the only product. Molecular oxygen insertion reaction in [PhCH2Co(dmgH)2]2-μ-Pz has also been monitored for comparison purpose.

The synthesis of cobaloximes, X/RCo(dThgH)2Py (X = Cl, R = Me, Et, n-Pr, n-Bu and Bn) has been described. All the complexes have been characterized by elemental analyses and NMR spectral studies. The molecular structures of ClCo(dThgH)2Py, MeCo(dThgH)2Py, EtCo(dThgH)2Py and BnCo(dThgH)2Py complexes are determined by X-ray crystallography. The electron withdrawing nature of 2-thienyl ring affects the NMR as well as electrochemical behavior of these complexes. The electrochemical reduction from Co(III) to Co(II) and from Co(II) to Co(I) are much easier in ClCo(dThgH)2Py as compared to chlorocobaloximes with the other dioximes (gH, dmgH, dpgH, dmestgH). The molecular oxygen insertion in the Co−C bond of benzyl complex (6) has been examined and a comparison of its reaction rate with other similar cobaloximes is discussed. The structural features of a dioxy complex Bn(O2)Co(dThgH)2Py (7) have also been reported.

New series of cobaloximes, RCo(dSePhgH)2Py (R = Cl, Me, Et, n-Pr, n-Bu, Bn, 4–ClC6H4CH2) have been synthesized and characterized by NMR and elemental analysis. Molecular oxygen insertion in the benzyl complexes under photochemical conditions has been carried out and a comparison of its reaction rate with other similar cobaloximes gives the order dmestgH > dSePhgH > dpgH > dSPhgH ≥ dmgH > gH. The molecular structures of ClCo(dSePhgH)2Py, MeCo(dSePhgH)2Py, BnCo(dSePhgH)2Py, 4–ClC6H4CH2Co(dSePhgH)2Py and a dioxy complex Bn(O2)Co(dSePhgH)2Py have been determined by X-ray crystallography. The SePh groups in these complexes adopt either up-down, up-down or down-down, down-down conformations in the solid state depending upon the steric bulk and steric interactions with the axial ligand and also their orientation affects the NMR chemical shifts.

In casting units, workers work under tough conditions to perform the desired task. These tough conditions normally give rise to various musculoskeletal disorders within the workers. These disorders emerge within the workers body due to repetitive lifting, differential lifting height, ambient conditions etc. For the minimization of musculoskeletal disorders it is quite difficult to model with mathematical difference or differential equations. In this paper the minimization of musculoskeletal disorders problem has been formulated using artificial neural networks model. But the existing neural network model has various drawbacks like large training time, huge data requirement to train for a non linear complex musculoskeletal disorders problem, the relatively large number of hidden nodes required etc. Hence, an attempt has been made to develop a non linear model using fuzzified neuron sub-models to overcome the above mentioned problems. These models would have the capability of representing solutions for minimizing musculoskeletal disorders needed for workers working in the casting units.

Ten mixed dioxime complexes RCo(L)(dmgH)Py [R = Cl, Me, Et, Bu, Benzyl] [L = dSPhgH (1–5) and dSEtgH (6–10)] have been synthesized and characterized by NMR. Formation of 1 and 6 is very fast and takes only 5 and 15 min in ethanol. Molecular oxygen insertion in 5 and 10 is monitored and forms mixture of products within 5 min. The crystal structure of 1, 4, 5, 6, 8 and 10 is reported. Benzyl ring is oriented over dmgH wing in both 5 and 10 and has a weak C–H…π interaction (3.33 A and 3.22 A) and this causes high upfield shift of the dmgH protons. Electrochemical study on 1, 4, 5, 6, 8 and 10 is also reported. Because of increased electron donation by SEt group, 6 is more difficult to reduce than 1.

This short review describes the synthesis and structural characteristics of methylene, xylylene and biphenyl-bridged dicobaloximes. The bridged dicobaloximes are easily synthesized by oxidative alkylation method and the yield of dicobaloxime depends on many factors like reaction time, solvent, dihalide:Co(I) ratio and also on the nature of dihalide used. The NMR and structural studies have been described. The cobalt-bound CH 2 and dioxime protons in xylylene-bridged dicobaloximes become nonequivalent at sub-zero temperature and this is caused by the restricted rotation of the Co–C bond. However, the nonequivalence in biphenyl-bridged dicobaloximes is caused by atropisomerism and/or restricted rotation of C–Ph/Co–C bond. Two cobaloxime units of biphenyl-bridged dicobaloximes are symmetrical, and can be looked at as two independent benzyl cobaloximes and there is no direct or indirect interaction between them. In the xylylene-bridged dicobaloxime, one cobaloxime unit affects the structural parameters of the other unit through axially bridged benzyl group, which is sandwiched between two dioxime wings.

The reactivity of aryl cobaloximes, ArCo(dmgH) 2 Py [Ar = Phenyl, 1-naphthyl, 2-naphthyl, 4-NMe 2 C 6 H 4 , 2-thienyl] with molecular oxygen and electrophiles (Br 2 and 2,4-dinitrobenzenesulfenyl chloride) has been investigated. All these complexes do not show any affinity toward molecular oxygen and the reaction with electrophiles either leads to ring substitution and/or the Co–C bond cleavage. The molecular structures of two new aryl cobaloximes and two ring substituted organometallic products have been determined crystallographically. The C–H⋯O intermolecular hydrogen bonding interactions in the crystal packing lead to different superstructural motifs.

Five benzyl cobaloximes with different thiodioximes, BnCo[d(SR)gH]2Py, have been synthesized and four of these complexes have been characterized by X-ray. The reactivity of these complexes towards molecular oxygen has been studied. The puckering of the Co(dioxime)2 unit, caused by dioxime side chain, the SR group, significantly influences the Co–C bond reactivity. Structural features in one of the oxygen inserted cobaloximes have been studied to confirm if puckering of dioxime is the guiding factor. The reactivity is also affected, to some extent, by the C–H…π interaction between the benzyl and the dioxime moiety.

Aryl cobaloximes, ArCo(dioxime)2Py (1–9) (Ar = phenyl, 1-naphthyl, 2-naphthyl; dioxime = dmgH, dpgH, gH) have been synthesized and characterized primarily by NMR and elemental analyses and molecular structures of four complexes have also been determined crystallographically. The electronic and steric effects of the aryl ring size and the equatorial dioxime affect the NMR chemical shifts and the X-ray structural parameters. The cyclic voltammetry study shows that the aryl cobaloximes are reduced electrochemically more easily as compared to the corresponding alkyl complexes. These complexes have a robust Co–C bond and are very stable in solution and show no sign of decomposition even on irradiation under oxygen atmosphere – an unusual property of any organocobaloxime.

The crystal and molecular structure of furfuryl(O2)Co(dmgH)2Py (1) has been determined by X-ray diffraction analysis. In the molecular structure of 1, the furfuryl ring oxygen is pointing inwards and is very close to one of the dmgH (Me) (2.625 A). It shows unusual C–H···O weak interaction which must be responsible for the observed 1:3 ratio of dmgH methyl protons in NMR spectrum. Also, theoretical calculations using DFT have been performed on 1 for the Co–O and CH2–C(furfuryl) bond rotation. Conformational energy diagrams derived from theoretical calculations also indicate that in most stable conformer the furfuryl ring oxygen is very close to one of the dmgH (Me) groups.

Alkyl and non-alkyl cobaloximes with bis(thiophenyl)glyoxime, X/RCo(dSPhgH)2Py (X = Cl, R = Me, Et, Pr, Bu, Bn) have been synthesized and characterized for the first time. The X-ray structures of t...

The complexes ArCH2Co(gH)(dpgH)Py have been synthesized and characterized by NMR. Molecular oxygen insertion into the Co−C bond in ArCH2Co(L)(dpgH)Py (L = gH, dmgH, chgH) complexes under photochemi...

4,4′-Disubstituted biphenyl-bridged dicobaloximes, Py(L)2Co-CH2-Ar-CH2-Co(L)2Py [L = dmgH, dpgH], have been synthesized and characterized. The cobalt-bound CH2 is diastereotopic and the dmgH (Me) shows nonequivalence in the 1H NMR. This may occur due to atropisomerism and/or restricted rotation of the C−Ph/Co−C bond. Two X-ray structures of the biphenyl-bridged dicobaloximes, reported for the first time, show no direct or indirect interaction between the two cobaloxime units [Co(dioxime)2Py]. The NMR spectra and X-ray structural details complement each other. Three redox processes, CoIII/CoII, CoII/CoI, and CoIV/CoIII, are observed in the CV study. Two cobalt centers are oxidized at different potentials as two discrete units even though these are symmetrically located with respect to each other with no interaction between them.

Benzyl cobaloximes, ArCH2Co(dioxime)2Py, with two different dioximes, glyoxime (gH) and dimesitylglyoxime (dmestgH), have been synthesized and characterized by 1H and 13C NMR and UV−vis spectroscopy. The dioxy adducts, ArCH2(O2)Co(dioxime)2Py, were prepared by the insertion of molecular oxygen into the Co−C under photochemical conditions. The rate of insertion depends upon the nature of the dioxime and follows the order dmestgH ≫ dpgH > chgH > dmgH > gH. The steric cis influence of the dioximes on the Co−C bond also follows the same order. The study also suggests that the interactions between the axial benzyl group and the dioximes have significant influence on the Co−C bond reactivity. Such interactions are also seen in the molecular structure of [C6H4CH2Co(gH)2(4-tBuPy)] and in the dioxy complexes 4-CN-C6H4CH2(O2)Co(dmestgH)2Py and 2-naphthylCH2(O2)Co(dmestgH)2Py. On the basis of the results we have supported the cage mechanism for the oxygen insertion into the Co−C bond.

The Co−C bond is activated toward homolysis due to the interactions between axial and equatorial dioxime ligands. Benzylcobaloxime gives an oxygen-inserted product, whereas the alkyl derivative forms air-stable cobalt(II). The stabilization of the axial R group due to the interaction between axial and equatorial ligands causes the reactivity difference.

Mono- and dinuclear cobaloximes with inorganic anions and pyrazine (Pz) as a base/bridging ligand were synthesized and characterized by 1H, 13C, UV/Vis and IR spectroscopy and X-ray structure analysis. Mononuclear complexes XCo(dioxime)2Pz were used as precursors for building homo- and heterodimetallic complexes. The X-ray crystal structures of ClCo(dmgH)2Pz, ClCo(dpgH)2Pz, [Co(dpgH)2(NO2)2]Na, and [Co(dmgH)2(NO2)2]2[Ag]2·H2O are reported. [Co(dmgH)2(NO2)2]2[Ag]2·H2O shows two AgI ions in different environments: one is in tetrahedral, whereas the other is in capped trigonal coordination and the metal-organic framework in this molecule shows helical structure. A cyclic voltammetry study in [XCo(dioxime)2]2-μ-Pz and XCo(dioxime)2Pz [dioxime = dmgH (dimethylglyoximato), dpgH (diphenylglyoximato)] is reported. The reduction, CoIII to CoII and CoII to CoI, is found to be more difficult in [XCo(dpgH)2]2-μ-Pz than in XCo(dpgH)2Pz. The CV data have been interpreted in terms of cobalt anisotropy. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

The insertion of sulfur dioxide into the Co−C bond in ArCH2Co(dioxime)2Py forms a mixture of ArCH2SO2Co(dioxime)2Py, ClCo(dioxime)2Py, and a neutral trinuclear complex, [(dpgH)2PyCoIII-μ-SO3]2CoII(MeOH)4. The inserted products 4-CN-C6H4CH2SO2Co(dpgH)2Py and C6H5CH2SO2Co(gH)2Py and the trinuclear complex have been structurally characterized by X-ray for the first time. The insertion of sulfur dioxide into the Co−C bond affects the orientation of the benzyl group.

Pyrazine (Pz) bridged benzyl dicobaloximes [ArCH2Co(dioxime)2]2-μ-Pz [dioxime = dmgH, dpgH] have been synthesized and characterized with 1H and 13C NMR. The complexes have been synthesized by a simple procedure in one-pot directly from the corresponding benzyl aqua cobaloxime. In the crystal structure of [PhCH2Co(dpgH)2]2-μ-Pz, two cobaloxime units are in eclipsed form whereas they were completely staggered in the reported [EtCo(dpgH)2]2-μ-Pz. This is due to the π–π interaction between the axial benzyl group and phenyl ring of the equatorial dpgH group. Both cis and trans isomer crystallized together in the crystal structure of [PhCH2Co(dpgH)(dmgH)]2-μ-Pz. The cyclic voltammetry study in [PhCH2Co(dioxime)2]2-μ-Pz [dioxime = dmgH, dpgH] shows two cobalt center mixed together due to electron delocalization through pyrazine and behaves like a monocobaloxime and the reduction potentials are much higher than the monocobaloximes.

3β-Hydroxyandrost-5-en-17-one (C19H28O2.CH3OH) has been prepared for undertaking its crystallographic analysis and to investigate the role of intra- and intermolecular interactions in steroids. The title compound crystallizes in the orthorhombic space group C2221 with unit cell parameters a = 6.7892(17), b = 12.624(2), and c = 41.136(5) A; V = 3525.7(12) A3 and Z = 8. The three-dimensional structure has been solved by direct methods. The final reliability index for the computed structure is 0.050 for 1088 observed reflections. Ring A exist in chair conformation, Ring B in half-chair conformation, and the Ring C assumes a distorted chair conformation. The five-membered Ring D adopts half-chair conformation. The A/B ring junction is quasi-trans while as B/C and C/D are trans-fused. The oxygen atom of the solvent molecule (CH3OH) is involved in O–H···O intermolecular interaction.

The synthesis and characterization of RCo(gH)2Py (R = methyl through decyl) and XCo(gH)2Py (X = Cl, Br, NO2, N3) is described. Most of these complexes are new and have been synthesized for the first time. The X-ray structure of N3Co(gH)2Py is reported. The cis−trans influence has been studied by 1H and 13C NMR, UV−vis, and X-ray diffraction. For a range of X ligands, a clear trend between the 1H and 13C chemical shifts of the axial and equatorial ligands as well as with the Co-dioxime CT band has been observed. More than 20 correlations have been found. δ(13C) values for CN, Pyα, Pyβ, and Pyγ in the alkylcobaloximes always occur upfield by 1−3 ppm compared to those in the inorganic cobaloximes, and δ(13C) for CN in gH complexes occur significantly upfield, by 12−13 ppm, compared to the values in the corresponding dmgH, chgH, and dpgH complexes.

We report the synthesis and crystallographic studies of paddlewheel-based methyl cobaloxime assembly formed from methyl cobaloxime, isonicotinic acid, and Zn(NO(3))(2). The cobaloxime units are assembled over two-dimensional metal-organic polyhedra constructed from isonicotinate and Zn metal ions.

A simple and general route to the synthesis of cobaloxime with mixed dioxime ligands, XCo(L)(L′)Py, L,L′=dmgH/dpgH and chgH/dpgH; X=Cl, Br, NO2, N3, has been described. These compounds are reported for the first time. The synthesis is confirmed by the X-ray structures of N3Co(dmgH)(dpgH)Py and N3Co(chgH)(dpgH)Py. The cis and trans effects on these complexes and on XCo(L)2Py (L=dmgH, chgH, dpgH; X=Cl, Br, NO2, N3) complexes have been studied by 1H-, 13C-NMR, UV, and X-ray. For a range of X ligands, a clear trend between the 1H, 13C chemical shifts of the equatorial and axial ligands as well as with the Co–dioxime CT band has been observed. The analysis of the 13C values and X-ray data shows that one dioxime wing effects the other dioxime wing in the mixed dioxime complexes.

A simple and general route to the synthesis of organocobaloxime with mixed dioxime ligands, RCo(dmgH)(dpgH)Py and RCo(chgH)(dpgH)Py, has been described. The 13C-NMR chemical shifts have been analysed to see whether one dioxime wing has any effect on the other dioxime wing. The first crystal structure of an organocobaloxime with mixed dioxime ligand in the same complex, BnCo(dmgH)(dpgH)Py and BnCo(chgH)(dpgH)Py, is reported.

The reactions of arene sulfenyl chlorides, ArSCl, (Ar=Ph, C6Cl5, 2,4 (NO2)2C6H3) with organocobaloximes, RCo(dmgH)2Py, (R=alkyl, benzyl and heteroaromaticmethyl) were carried out under thermal and photochemical conditions. A variety of organic and organometallic products are formed depending upon the substrate cobaloxime. For 3-methoxybenzyl and heteroaromaticmethyl cobaloximes the results suggest that they represent a unique class of cobaloximes whereby both the aromatic ring as well as the CoC bond are highly activated towards attack by the arene sulfenyl chloride. Both homolytic as well as heterolytic pathways are operative.

All three methyl groups in mesitylene become nonequivalent in the 1 H NMR spectra of PhCH 2 Co(dmestgH) 2 Py, PhCH 2 (SO 2 )Co(dmestgH) 2 Py, and PhCH 2 (O 2 )Co(dmestgH) 2 Py, due to weak interactions between the axial benzyl and the equatorial dioxime ligands.

A comparative study of the structural parameters of bis(dioxime) vitamin B12 models reveal an interesting squeezing of the metallabicycle. The lateral compression and the butterfly bending angle have a common origin in the steric bulk of the dioxime substituents. The first crystal structure of an organocobaloxime with cyclohexanedionedioxime(chgH) as the equatorial ligand is also reported. The compound MeCo(chgH)2Py crystallises in the monoclinic system, with the space group P21/n with Z=4 and unit cell parameters a=8.7074(9), b=9.3989(8), c=23.886(2) A and β=91.862(8)°.

Twenty six complexes, pyrazine bridged organodicobaloximes of the type RCo(L 2 )-pyrazine-Co(L 2 )R where R is alkyl group and L is dmgH − /dpgH − have been synthesised. It was found that one could synthesise such complexes in one pot directly from the alkyl(aquo)cobaloximes without converting it to the alkylcobaloxime dimer, as reported in the literature. 1 H-NMR studies have revealed that the pyrazine ring protons experience considerably more cis influence than the H α protons of the pyridine in simple alkylcobaloximes. This is presumably because the pyrazine ring protons are in close proximity to two metallabicycles while the H α protons of the simple alkylcobaloximes are influenced by only one metallabicycle. The trends in the Co–C charge transfer transition and N–O, N–O′ frequencies are similar to the alkyl (pyridine) cobaloximes. Low resolution x-ray crystal structure of one of the dicobaloximes, [EtCo(dpgH) 2 ] μ -Pz indicates that the two subunits of the molecule rotate around the two Co–N single bonds with the result that the two metallabicycles are completely staggered with respect to each other.

In this investigation the analysis and design of thrust bearing by a stochastic approach for the effect of the viscosity variation due to thermal effects and slip effects have been studied. To discuss the optimum design criterion the results for load capacity and frictional torque are obtained for commonly used lubricants by using the interior penalty function method. The relative performances of different lubricants under optimum conditions have also been presented.

In the present investigation the analysis and design of a thrust bearing by the stochastic approach in order to assess the viscosity-density variations due to thermal effects have been studied. To discuss the optimum design criterion the results for load capacity and frictional torque are obtained for commonly used lubricants using the interior penalty function method. The relative performances for different lubricants under optimum conditions are also presented.

The insertion of molecular oxygen into the CoC bond in organocobaloximes under thermal and photochemical conditions has been studied. Kinetic studies have shown that the reaction is of first order with respect to both the complex and oxygen. The thermal decomposition of the organocobaloximes and their insertion products has been carried out in benzene and methanol and a mechanism is proposed for the decomposition.

The photo-oxidation and the photo-dehydrochlorination of a series of PVC samples having different isotactic contents have been studied in the presence of oxygen. The build-up of carbonyl groups was found to decrease as the isotactic content was increased. Conversely, the dehydrochlorination quantum yield appeared to increase linearly as the isotactic content increased. It is proposed that the former result is due to a less favoured hydrogen abstraction reaction at the isotactic triads, resulting from a higher shielding of the hydrogen atoms at CHCl groups. The latter result is associated with both the occurrence of some chlorine atoms of low dissociation energy located at a definite type of isotactic triad and the favoured hydrogen abstraction reaction at the CH2 group in syndio and heterotactic triads. The conclusions are discussed on the basis of the local conformations of the various triads. In particular, the role of the isotactic GTTG− triad conformation in the mechanisms above is emphasized.

The title ester {6-(1,1-dimethyl-2-propenyl)-2-oxo-2H-furo[2,3-h][1]benzopyran-5-yl acetate, C 18 H 16 O 5 }, is a furanocoumarin. The pyrone, phenyl and furan rings are planar. Molecules are held together by C-H...O hydrogen bonds.

The photo-oxidation of PVC films, stabilised by various amounts of Cyasorb UV 1988 benzylidine malonate, was studied by UV and IR spectrophotometry. A screen effect of reasonable efficiency was observed on initial rates of carboynl growth; however, for the lowest stabiliser concentrations, a relatively quick chemical transformation of the stabiliser was observed. The dependence of its rate upon the initial stabiliser concentration shows that it is due to reactions of the stabiliser with reactive species resulting from polymer photo-oxidation. These species could be chlorine radicals able to react by addition to the stabiliser double bond.

SummaryWe investigated the effects on reproductive functions of feeding adult rhesus monkeys on a diet of irradiated wheat flour and potato. Wheat flour and potatoes were exposed to 75 000 and 10 000 rad, respectively, of gamma-irradiation and then fed to the animals. Various parameters of reproductive function were compared with those of animals fed on unirradiated food. These were: external changes in the reproductive organs, menstrual cycle, vaginal cytology, assay of urinary hormones (oestrogens and pregnanediol), and post-mortem histopathological examination of the reproductive organs. At the end of 3 months, the experimental and control animals behaved similarly with regard to their reproductive functions.

A basic criterion in the design of refrigerated commercial warehouse is to minimize the operational energy. Although the input parameters like outside temperature, solar radiation, material properties and the dimensions of walls and roof are random in nature, very little fluctuations are desired in the inside conditions. A design produced by considering the randomness of the input variables and the fixed inside conditions would be more rational and realistic than the one produced according to deterministic procedures. In addition to the thickness of insulation for the walls and roof, the thickness of walls, orientation of the building and the building envelope parameters also influence the energy requirements of a warehouse. In this work the probability based optimum design of refrigerated warehouses, using interior penalty function method of optimization, is considered. For the calculation of heat gain, the design day based on the maximum value of mean plus three times the standard deviation of solar-air temperature, computed from the hourly meteorological data, is chosen. The optimum point is checked with Kuhn-Tucker conditions. A sensitivity analysis of the optimum results is also performed.

The grafting of acrylic acid on radiation peroxidized Teflon-FEP films exhibits features differing from those observed when grafting the monomer on polyethylene films. The differences result from both physical factors (diffusion of the monomer into the film) and chemical factors. Among the latter, one has to consider differences in the peroxidation mechanism which generates hydroperoxides by a chain reaction in polyethylene but only leads to trapped radicals in the perfluorinated polymer. A comparison of the results obtained in these studies helps to better understanding of the behaviour of these two polymers.

Benzyl and para -substituted benzylcobaloximes react readily with thiocyanogen in the dark under anaerobic conditions to give a variety of products: thiocyanates, isothiocyanates, bibenzyl and benzyl ether of dimethylglyoximes. The products are believed to result from an oxidative dealkylation process on the intermediate five-coordinate organocobaloxime species.

The interaction between radial and rotational inertia and density-viscosity variations due to temperature changes in a thrust bearing was investigated and a procedure for the optimum design for the load capacity and friction torque was developed.

The simultaneous effect of inertia and centrifugal, thermal and cavitation properties in bearing design is considered. Equations for the loadcarrying capacity and frictional torque are developed. Optimum designs are developed for different parameters. A speed corresponding to no-cavitation conditions is obtained and then the maximum load-carrying capacity and minimum frictional torque for the given bearing parameters are determined.