Full Text Available U Zrenjaninu je od 25. do 28. oktobra 2005. godine održana IV srpsko-bugarska konferencija na temu "Svakodnevna kultura u postsocijalističkom periodu u Srbiji i Bugarskoj: balkanska transformacija i evropska integracija". Konferenciju su organizovali Etnografski institut SANU iz Beograda, Etnografski institut i muzej BAN iz Sofije i Narodni muzej Zrenjanin.
Mickovski, Jovan [Faculty of Technology and Metallurgy, St. ' Cyril and Methodius' University, Skopje (Macedonia, The Former Yugoslav Republic of)
This Conference aims to be a central event in the metallurgy research of Balkan, fulfilling the goals to present the most outstanding relevant developments in modern metallurgy; to inspire high standards of excellence in pure and applied metallurgy research; to attract outstanding scientists to present central lectures on modem metallurgical research, and on the challenges imposed by the needs of society; to inspire the young generation of metallurgists in Balkan and other countries. Following these lines, the 3. Balkan Conference on Metallurgy will provide a unique opportunity for academic and industrial metallurgists from the Balkan countries and wider, to exchange ideas, expertise, and experience on topics related to the theme of the Conference - Balkan Metallurgy in Search for New Ways of Development. The aim of the organizers was to bring together distinguished experts, not only to present their work, but also to discuss the major scientific and technological challenges facing metallurgy in this millennium.The 6 sections of the conference were entitled: Section A: Extractive metallurgy; Section B: Physical metallurgy and materials science - ferrous metals and non ferrous metals; Section C: Management, maintenance control and optimization of metallurgical processes; Section D: New technologies and techniques; Section E: Refractory and powder; Section F: Corrosion and protection of metals. Papers relevant to INIS are indexed separately.
Sotic, O; Vranic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)
Nuclear research reactor RB tn the Nuclear Engineering Laboratory at the Institute of Nuclear Sciences 'Boris Kidric' in Vinca is the first reactor system built in Yugoslavia in 1958. In this report, the basic technical characteristics of this reactor are described, as well as the experimental possibilities it offers to the users. Its relatively simple construction and flexibility enables direct measurements of a series of physical parameters, and the absence of the biological protection shield makes it very useful for Various biological and other irradiations and dosimetric measurements Where strong neutron source is required. (author) Istrazivacki nuklearni reaktor RB u Laboratoriji za nuklearnu energetiku i tehnicku fiziku Instituta za nuklearne nauke 'Boris Kidric' u Vinci je prvi reaktorski sistem izgradjen u Jugooslaviji 1958. godine. U ovom radu opisane su osnovne tehnicke karakteristike tog reaktora, kao i mogucnosti za izvodjenje eksperimenata koje on pruza korisnicima. Njegova relativno jednostavna konstrukcija i fleksibilnost omogucavaju da se na njemu izvrse direktna merenja niza fizickih parametara, a s druge strane odsustvo bioloskog zastitnog omotaca cini ga veoma pogodnim za razna bioloska i druga ozracivanja, a takodje i dozimetrijska merenja gde se zahteva snazan izvor neutrona. (author)
Stankovski, Mile J [ed.
ETAI 2005 is the seventh of the series of theme conferences organized by the Society for ETAI of the Republic of Macedonia. The previous ones include ETAI '82, '85, '89, '93, 2000 and 2003. Traditionally, the Conference is held in the ambient of the reach rarity of the nature and the culture of Ohrid Coastal Area, protected by UNESCO. The scope of the Conference, following its cross-disciplinary character, is aimed towards studying and exposing both the theoretical and applied aspects in the field of Electronics, Telecommunications, Automatics and Informatics. The aim of the Conference is directed towards encouraging and stimulating the professional exchange of information and knowledge among people from academic institutions and from business and industry enterprises in the fields covered by ETAI. At the same time the Conference will enable a close and direct get-togetherness framework important for sharing people ideas and professional knowledge for the benefit of the common progress. The program of the ETAI 2003 contains three plenary lectures and 20 regular sessions including 85 contributed papers.
Eesti Raamatukoguhoidjate Ühingu esindus osales 27.-28. aprillini Vilniuse parlamendis toimunud rahvusvahelisel konverentsil „Raamatukogu: teave ja teadmised kõigile“. Juuresolevatel fotodel Eesti Raamatukoguhoidjate Ühingu juhatuse esinaine Katre Riisalu ja Viljandi Linnaraamatukogu töötaja Veronika Raudsepp Linnupuu. Nr. 6 juttu Tallinna Keskraamatukogu esindaja Angelica Õunapuu ja Tartu Ülikooli esindaja Mai Põldaasa ettekannetest
354-355, - (2007), s. 23-28 ISSN N. [Mižnarodna onomastyčna konferencija /12./. Černivci, 31.10.2007-03.11.2007] R&D Projects: GA MŠk(CZ) LC546 Institutional research plan: CEZ:AV0Z90610518 Keywords : Old Church Slavonic Subject RIV: AI - Linguistics
Full Text Available "New Contexts in Teaching and Learning:International Perspectives" četvrta je međunarodna godišnja konferencija koju organizuje Centar za sociologiju, antropologiju i politiku (C-SAP u okviru Akademije za visoko obrazovanje Univerziteta u Birmingemu.
Lee, Jong Hyun; Kim, Yeon-Gu; Lee, Gyun Min
The sialic acid of glycoproteins secreted by recombinant Chinese hamster ovary (rCHO) cells can be impaired by sialidase under culture conditions which promote the extracellular accumulation of this enzyme. To investigate the effect of Bcl-xL overexpression on the sialylation of glycoproteins produced in rCHO cell culture, two rCHO cell lines producing the same Fc-fusion protein, which were derived from DUKX-B11 and DG44, respectively, were engineered to have regulated Bcl-xL overexpression using the Tet-off system. For both cell lines, Bcl-xL overexpression improved cell viability and extended culture longevity in batch cultures. As a result, a maximum Fc-fusion protein titer increased by Bcl-xL overexpression though the extent of titer enhancement differed between the two cell lines. With Bcl-xL overexpression, the sialylation of Fc-fusion protein, which was assessed by isoelectric focusing gel and sialic acid content analyses, decreased more slowly toward the end of batch cultures. This was because Bcl-xL overexpression delayed the extracellular accumulation of sialidase activity by reducing cell lysis during batch cultures. Taken together, Bcl-xL overexpression in rCHO cell culture increased Fc-fusion protein production and also reduced the impairment of sialylation of Fc-fusion protein by maintaining high viability during batch cultures. © 2015 American Institute of Chemical Engineers.
Hassina, Bazaze; Raouf, Zehioua; Menial, A. H.
Photochemical smog is extremely toxic to animal and plant life, and damages paint, rubber, and plastics. In our discussion of photochemical smog chemistry we outlined a general reaction mechanism, that is reproduced with appropriate rate constants. We wish to integrate the rate equation from this mechanism to examine the temporal concentration dynamics of RH, RCHO, NO 2 , and O 3 . The method, called method of photostationary state relation (PSSA) of Bodenstein , comes back to consider compounds intermediate concentration 'C' put in game in a reaction, have a weak concentration in relation to the one of the other species presents and remain practically constant.(Author)
On 21 September 1990, the General Conference, by resolution GC(XXXIV)/RES/530, adopted a Code of Practice on the International Transboundary Movement of Radioactive Waste and requested the Director General - inter alia - to take all necessary steps to ensure wide dissemination of the Code of Practice at both the national and the international level. The Code of Practice was elaborated by a Group of Experts established pursuant to resolution GC(XXXII)/RES/490 adopted by the General Conference in 1988. The text of the Code of Practice is reproduced herewith for the information of all Member States [Russian] 21 sentjabrja 1990 goda General'naja konferencija prinjala rezoljuciju GC(XXXIV)/RES/530 o Kodekse praktiki v oblasti mezhdunarodnogo transgranichnogo peremeshhenija radioaktivnyh othodov i predlozhila General'nomu direktoru , v chastnosti, prinjat' vse neobhodimye mery dlja obespechenija shirokogo rasprostranenija Kodeksa praktiki kak na nacional'nom, tak i na mezhdunarodnom urovnjah. Kodeks praktiki byl podgotovlen gruppoj jekspertov , uchrezhdennoj vo ispolnenie rezoljucii GC(XXXII)/RES/490, prinjatoj General'noj konferenciej v 1988 godu. Tekst Kodeksa praktiki vosproizvoditsja nizhe dlja informacii vseh gosudarstv-chlenov.
Baek, Eric; Lin Kim, Che; Gyeom Kim, Mi
Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemical...... autophagy inhibitors on the specific productivity (qp), nine chemical inhibitors that had been reported to target three different phases of autophagy (metformin, dorsomorphin, resveratrol, and SP600125 against initiation and nucleation; 3-MA, wortmannin, and LY294002 against elongation, and chloroquine...... and bafilomycin A1 against autophagosome fusion) were used to treat three recombinant CHO (rCHO) cell lines: the Fc-fusion protein-producing DG44 (DG44-Fc) and DUKX-B11 (DUKX-Fc) and antibody-producing DG44 (DG44-Ab) cell lines. Among the nine chemical inhibitors tested, 3-MA, dorsomorphin, and SP600125...
Sekhar, V.C.; Plapp, B.V.
Transient kinetic data for partial reactions of alcohol dehydrogenase and simulations of progress curves have led to estimates of rate constants for the following mechanism, at pH 8.0 and 25 degrees C: E in equilibrium E-NAD+ in equilibrium *E-NAD+ in equilibrium E-NAD(+)-RCH2OH in equilibrium E-NAD+-RCH2O- in equilibrium *E-NADH-RCHO in equilibrium E-NADH-RCHO in equilibrium E-NADH in equilibrium E. Previous results show that the E-NAD+ complex isomerizes with a forward rate constant of 620 s-1. The enzyme-NAD(+)-alcohol complex has a pK value of 7.2 and loses a proton rapidly (greater than 1000 s-1). The transient oxidation of ethanol is 2-fold faster in D 2 O, and proton inventory results suggest that the transition state has a charge of -0.3 on the substrate oxygen. Rate constants for hydride ion transfer in the forward or reverse reactions were similar for short-chain aliphatic substrates (400-600 s-1). A small deuterium isotope effect for transient oxidation of longer chain alcohols is apparently due to the isomerization of the E-NAD+ complex. The transient reduction of aliphatic aldehydes showed no primary deuterium isotope effect; thus, an isomerization of the E-NADH-aldehyde complex is postulated, as isomerization of the E-NADH complex was too fast to be detected. The estimated microscopic rate constants show that the observed transient reactions are controlled by multiple steps
Souza, Cristiane Duarte Ribeiro de; Silva, Suellem Deodoro; Silva, Marcelino Aurélio Vieira da; D’Agosto, Márcio de Almeida; Barboza, Arthur Prado
Road transportation has contributed to increased emissions of conventional air pollutants and, consequently, to the increase in problems associated with the environment and human health, depending on the type of pollutant and the concentration of it. To support the development of public policies aimed to decrease total tonnes of emissions, we used a bottom-up approach to estimate the amount of air pollutants, such as carbon monoxide (CO), total hydrocarbons (THC), nitrogen oxides (NO x ), particulate matter (PM), and aldehydes (RCHO), that are emitted by road transportation in the state of Rio de Janeiro (RJ) from 1980 to 2010. The results from 2010 show that cars are responsible for 55% of CO emissions, 61% of THC emissions, and 93% of RCHO emissions. Due to the use of hydrated ethanol and compressed natural gas (CNG) instead of petroleum based fuels during the period analyzed, 1,760,370 t of air pollutant emissions were avoided. Compared to Brazil, in 2010, RJ had a quantity of emissions per vehicle from 12% (CO) to 59% (PM) smaller than the national average. As strategies to reduce air pollutant emissions, we consider reducing the intensity of use, with a proportional reduction in emissions, and increased the use of biodiesel. - Highlights: ► We estimate road transportation emissions for Rio de Janeiro from 1980 to 2010. ► C gasoline was most responsible for CO (74%) and diesel for PM (91%). ► Emissions/vehicle for Rio de Janeiro are (12% to 59%) smaller than Brazilian. ► 1,760,370 t of emissions was avoided using non-petroleum-based fuels. ► Strategies to reduce the emissions of these air pollutants were proposed.
JENSEN, NR; HJORTH, J; LOHSE, C
A 480 L evacuable reaction chamber, equipped with FT-IR spectroscopy on-line and ion chromatography off-line, has been used to study the gas phase reaction between the nitrate radical, NO3, and the reduced organic sulphur compounds CH3CH2SH, (CH3CH2)2S, (CH3CH2)2S2, and CH3CH2SCH3 in air. The pro......A 480 L evacuable reaction chamber, equipped with FT-IR spectroscopy on-line and ion chromatography off-line, has been used to study the gas phase reaction between the nitrate radical, NO3, and the reduced organic sulphur compounds CH3CH2SH, (CH3CH2)2S, (CH3CH2)2S2, and CH3CH2SCH3 in air......, and CH3SSCH3 lead to the conclusion that all these species, in the reaction with the NO3 radical, follow a similar degradation mechanism producing SO2, H2SO4, R-SO3H, R-CHO, and R-CH2ONO2, as the main reaction products. The inital step of the reaction of NO3 with R-S-R and R-S- H type (R = CH3, CH2CH3...
Ejidike, Ikechukwu P.; Ajibade, Peter A.
The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030
Full Text Available Abstract Background Chondromodulin-I (ChM-I is an anti-angiogenic glycoprotein that is specifically localized at the extracellular matrix of the avascular mesenchyme including cartilage and cardiac valves. In this study, we characterized the expression pattern of ChM-I during early pregnancy in mice in vivo and its effect on invasion of trophoblastic cells into Matrigel in vitro. Results Northern blot analysis clearly indicated that ChM-I transcripts were expressed in the pregnant mouse uterus at 6.5-9.5 days post coitum. In situ hybridization and immunohistochemistry revealed that ChM-I was localized to the mature decidua surrounding the matrix metalloproteinase-9 (MMP-9-expressing trophoblasts. Consistent with this observation, the expression of ChM-I mRNA was induced in decidualizing endometrial stromal cells in vitro, in response to estradiol and progesterone. Recombinant human ChM-I (rhChM-I markedly inhibited the invasion through Matrigel as well as the chemotactic migration of rat Rcho-1 trophoblast cells in a manner independent of MMP activation. Conclusions This study demonstrates the inhibitory action of ChM-I on trophoblast migration and invasion, implying the potential role of the ChM-I expression in decidual cells for the regulated tissue remodeling and angiogenesis at feto-maternal interface.
Pokhrel, Suman; Huo Lihua; Zhao Hui; Gao Shan
Fine powder of Cr 1.8 Ti 0.2 O 3 (CTO) was prepared by citrate combustion technique followed by compacting into discs of 40 mm diameter. Discs were used as radio frequency sputtering targets and coated on a hollow ceramic tube of 4 mm length comprising two Au-electrodes with 4-probe contact and on Al 2 O 3 slices with interdigitated gold electrodes. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy techniques. The resistance of the film derived from alternate current impedance measurement in ambient air was found to decrease with increasing temperature. The activation energy was found to be 0.39 eV. These films were exposed to various concentrations of alcohols followed by determination of sensor response, reversibility, potential stability and reproducibility. The sensor response was attributed to the surface catalytic reaction of R-OH with O - (ads) to form adsorbed R-CHO
Ikechukwu P. Ejidike
Full Text Available The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(LCl2(H2O] (where L = tridentate NNO ligands. The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS radicals, with DPPH scavenging capability in the order: [(PAEBODRuCl2] > [(BZEBODRuCl2] > [(MOABODRuCl2] > [Vit. C] > [rutin] > [(METBODRuCl2], and ABTS radical in the order: [(PAEBODRuCl2] < [(MOABODRuCl2] < [(BZEBODRuCl2] < [(METBODRuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10, melanoma cancer cell (UACC-62 and breast cancer cell (MCF-7 by SRB assay.
Jones, W.D. II.
The complex PPN + CpV(CO) 3 H - (Cp=eta 5 -C 5 H 5 and PPN = (Ph 3 P) 2 ) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN + CpV(CO) 3 H - reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN + [CpV(C) 3 X] - and in some cases the binuclear bridging hydride PPN + [CpV(CO) 3 ] 2 H - . The borohydride salt PPN + [CpV(CO) 3 BH 4 ] - has also been prepared. The reaction between CpV(CO) 3 H - and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO) 3 H - . Sodium amalgam reduction of CpRh(CO) 2 or a mixture of CpRh(CO) 2 and CpCo(CO) 2 affords two new anions, PPN + [Cp 2 Rh 3 (CO) 4 ] - and PPN + [Cp 2 RhCo(CO) 2 ] - . CpMo(CO) 3 H reacts with CpMo(CO) 3 R (R=CH 3 ,C 2 H 5 , CH 2 C 6 H 5 ) at 25 to 50 0 C to produce aldehyde RCHO and the dimers [CpMo(CO) 3 ] 2 and [CpMo(CO) 2 ] 2 . In general, CpV(CO) 3 H - appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO) 3 H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO) 3 H - generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO) 3 H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species
Jones, W.D. II
The complex PPN/sup +/ CpV(CO)/sub 3/H/sup -/ (Cp=eta/sup 5/-C/sub 5/H/sub 5/ and PPN = (Ph/sub 3/P)/sub 2/) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN/sup +/ CpV(CO)/sub 3/H/sup -/ reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN/sup +/(CpV(C)/sub 3/X)/sup -/ and in some cases the binuclear bridging hydride PPN/sup +/ (CpV(CO)/sub 3/)/sub 2/H/sup -/. The borohydride salt PPN/sup +/(CpV(CO)/sub 3/BH/sub 4/)/sup -/ has also been prepared. The reaction between CpV(CO)/sub 3/H/sup -/ and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)/sub 3/H/sup -/. Sodium amalgam reduction of CpRh(CO)/sub 2/ or a mixture of CpRh(CO)/sub 2/ and CpCo(CO)/sub 2/ affords two new anions, PPN/sup +/ (Cp/sub 2/Rh/sub 3/(CO)/sub 4/)/sup -/ and PPN/sup +/(Cp/sub 2/RhCo(CO)/sub 2/)/sup -/. CpMo(CO)/sub 3/H reacts with CpMo(CO)/sub 3/R (R=CH/sub 3/,C/sub 2/H/sub 5/, CH/sub 2/C/sub 6/H/sub 5/) at 25 to 50/sup 0/C to produce aldehyde RCHO and the dimers (CpMo(CO)/sub 3/)/sub 2/ and (CpMo(CO)/sub 2/)/sub 2/. In general, CpV(CO)/sub 3/H/sup -/ appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)/sub 3/H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)/sub 3/H/sup -/ generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)/sub 3/H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species.
Behnke, Wolfgang; Zetzsch, Cornelius
Br[toluene] ~ 100). Formation of aldehydes (R-CHO) interferes with the chain reaction (1) - (3) markedly, since kBr[O3] ≈kBr[R-CHO]. The chain reaction is limited by availability of ozone (degradation of HCs by atomic Cl stops completely with vanishing ozone), of HO2 (HCs are required to form HO2) and of aerosol. The central question is: will sufficient HO2 be formed from degradation of HCs to explain the magnitude of the formed Br2 and BrCl in our experiments? We found that the formation of HO2 should be by a factor of 2-4 larger to explain the formation of Br2 and BrCl. Which other sources for the formation of HOBr besides reaction (2a) are then available? The rate of CH3O2with BrO is 25% of that with HO2 (Enami, S.; Yamanaka, T.; Nakayama, T.; Hashimoto, S.; Kawasaki, M.; Shallcross, D.E.; Nakano, Y.; Ishiwata, T., J. Phys. Chem. A, 11, 3342 - 3348, 2007), suggesting that other RO2 radicals must contribute. In our model calculations we use this rate constant for all RO2 radicals to obtain reasonable agreement between the produced HOBr and the formed BrCl and Br2 necessary for our experimental degradation results. So reaction scheme (1) - (3) should be completed by: BrO + RO2 => HOBr + products (2b) The German Science Foundation (DFG) supported this research in unit 783 (HALOPROC).
A study of fundamental reaction pathways for transition metal alkyl complexes. I. The reaction of a nickel methyl complex with alkynes. Ii. The mechanism of aldehyde formation in the reaction of a molybdenum hydride with molybdenum alkyls
Huggins, John Mitchell [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
I. This study reports the rapid reaction under mild conditions of internal or terminal alkynes with methyl (acetyl-acetonato) (triphenylphosphine) nickel (1) in either aromatic or ether solvents. In all cases vinylnickel products 2 are formed by insertion of the alkyne into the nickel=methyl bond. These complexes may be converted into a variety of organic products (e.g. alkenes, esters, vinyl halides) by treatment with appropriate reagents. Unsymmetrical alkynes give selectively the one regioisomer with the sterically largest substituent next to the nickel atom. In order to investigate the stereochemistry of the initial insertion, a x-ray diffraction study of the reaction of 1 with diphenylacetylene was carried out. This showed that the vinylnickel complex formed by overall trans insertion was the product of the reaction. Furthermore, subsequent slow isomerization of this complex, to a mixture of it and the corresponding cis isomer, demonstrated that this trans addition product is the kinetic product of the reaction. In studies with other alkynes, the product of trans addition was not always exclusively (or even predominantly) formed, but the ratio of the stereoisomers formed kinetically was substantially different from the thermodynamic ratio. Isotope labeling, added phosphine, and other experiments have allowed us to conclude that the mechanism of this reaction does involve initial cis addition. However, a coordinatively unsaturated vinylnickel complex is initially formed which can undergo rapid, phosphine-catalyzed cis-trans isomerization in competition with its conversion to the isolable phosphine-substituted kinetic reaction products. II. The reaction of CpMo(CO)3H (1a) with CpMo(CO)3R (2, R= CH3, C2H5) at 50°C in THF gives the aldehyde RCHO and the dimers [CpMo(CO)3]2 (3a) and [CpMo(CO)2]2 (4a). Labeling one of the reactants with a methylcyclopentadienyl ligand