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Objective To reduce the toxicity and side effects of arsenic trioxide (ATO) and provide a new approach for the treatment of primary liver cancer, a folic acid-modified calcium arsenite liposomal “target-controlled” drug delivery system (FA-LP-CaAs) was fabricated using the reverse microemulsion method. Methods A Malvern particle size analyzer and a transmission electron microscope were employed to determine the particle size, distribution, zeta potential and morphology of FA-LP-CaAs. Further, inductively coupled plasma emission spectrometry was employed to determine the drug loading capacity, entrapment efficiency, and in vitro release behavior of FA-LP-CaAs. To determine its toxicity in human hepatoma cells (HepG2) and human normal hepatocytes (LO2) and its effect on HepG2 cell cycle and apoptosis, the MTT method was used. Laser confocal and flow cytometry were also employed to determine the uptake of FA-LP-CaAs by cells. After establishing a mouse liver cancer model, the in vivo distribution of the drug included in the formulation was investigated using in vivo fluorescence. To evaluate the liver cancer targeting and anti-tumor effects of FA-LP-CaAs in vivo, the distribution of ATO in tissues and changes in tumor volume and body weight after liposomal administration were investigated using hematoxylin-eosin (HE)-stained tumor sections. Results The particle size, zeta potential and PDI of FA-LP-CaAs were (122.67 ± 2.18) nm, (12.81 ± 0.75) mV and 0.22 ± 0.01, respectively, while its drug loading capacity was 18.49% ± 1.14%. In vitro experimental results revealed that FA-LP-CaAs had a strong killing effect on HepG2 cells. Further, the cell uptake capacity of this formulation was found to improve. Based on in vivo assessments, FA-LP-CaAs could significantly increase the distribution of ATO in tumor sites and inhibit tumor growth. Conclusions Herein, an FA-LP-CaAs formulation was successfully fabricated. This liposomal drug delivery system had a round appearance, uniform particle size, good polydispersity coeffi-cient, evident “core-shell” structure, high drug loading capacity and pH response, tumor targeted drug delivery and sustained drug release. These findings support further research and the application of ATO as an anti-liver cancer prodrug and provide a new method for the treatment of liver cancer.

We present a new experimental method for measuring inner-shell ionization cross sections of low-charged ions colliding with hydrogen gas target in a storage ring. The method is based on a calibration by the well-known differential cross sections of proton elastic scattering on nuclei. K-shell ionization cross section of 1047(100) barn for the 95 MeV/u 58Ni19+ ions colliding with hydrogen atoms was obtained in this work. Compared to the measured ionization cross section, a good agreement is achieved with the prediction by the Relativistic Ionization CODE Modified program (RICODE-M).

The differences in catalytic activity between two catalyst ligands of Buchwald–Hartwig amination reaction, BrettPhos versus RuPhos, were investigated using density functional theory (DFT) calculations. The reaction process consists of three consecutive steps: (1) oxidative addition, (2) deprotonation, and (3) reductive elimination. Among them, the rate-limiting step of Pd-BrettPhos catalytic system is oxidative addition but that of Pd-RuPhos catalytic system is reductive elimination due to their differences in steric hindrance and electronic structure. It was also revealed that amines with large-size substituents or halides with electron-withdrawing groups would reduce the activation energy barriers of the reactions. The insights gained from the calculations of the Buchwald–Hartwig amination reaction would be helpful for the rational designing of new catalysts and reactions.

High Intensity heavy-ion Accelerator Facility (HIAF) project is being constructed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). An in-flight High energy FRagment Separator (HFRS) at HIAF was designed to study the properties of rare isotopes far away from the line of beta stability and their involved nuclear reactions of astrophysics interests. HFRS is a two-stage magnetic system which consists of Pre-Separator and Main-Separator. The maximum magnetic rigidity of 25 Tm was designed in particular for experiments with very neutron-rich rare isotopes beams and studies of hypernuclei and Δ-resonances in exotic nuclei. A dispersive mode and an achromatic mode were designed for different experimental requirements. The HFRS device can be used to separate and purify the rare isotopes produced by the projectile fragmentation of all primary beams up to Uranium or by the projectile fission of Uranium ions via Bρ-ΔE-Bρ method. The detailed HFRS ion-optical design including the first order and the higher order, and the magnet specification were presented in this paper.

The Shuangshan alkaline complex located in the Henan province of China is a newly discovered, potentially giant niobium (Nb) deposit. A variety of Nb-bearing minerals including pyrochlore, zircon, and titanite have been identified in this deposit. Distinct textural and chemical differences of pyrochlore and zircon indicate that both have different origins. The magmatic pyrochlore and zircon both have euhedral grains with small sizes. On the other hand, hydrothermal pyrochlore is mainly intergrown on the edge or inside of hydrothermal zircon in the form of an aggregate. Compared with magmatic pyrochlore, the contents of F, Ca, and Na in hydrothermal pyrochlore are obviously high. The texture and composition of hydrothermal pyrochlore and zircon indicate that Ca-bearing hydrothermal alteration resulted in the migration of Nb from Nb-bearing zircon and the reprecipitation of Nb to form aggregate pyrochlore. However, the quantitative calculation shows that the amount of Nb migrated from zircon is very small. Therefore, this study suggests that hydrothermal alteration plays a certain role in the redistribution of Nb, but the enrichment of Nb is limited.

Numerous theoretical simulation works have predicted the fantastic properties of arsenene, such as a tunable band gap, topological states, and a high carrier mobility. However, the experimental syn...

The modulation of selectivity of transfer hydrogenation of alkynes to E-alkenes using formic acid is a challenge due to the limited knowledge of the complex reaction network, including oxidative addition, decarboxylation, reductive elimination, Z → E isomerization, and β-H elimination. Here, the search for the reaction pathway and experiment explorations revealed that the selectivity of Pd(PMe3)4-catalyzed hydrogenation of 1-phenyl-1-propyne to (E)-1-phenylpropene is controlled by the water content in the aqueous solution of formic acid and the reaction time. The combination of an automatic reaction pathway search and density functional theory (DFT) calculations found that the intermolecular hydrogen bonds with water molecules have an influence on lowering the free energy activation barrier of transition states in the oxidative addition steps. The reasonable reaction barriers of Z → E isomerization and hydrogenation result in the dependence of selectivity on reaction time, which has been supported by experiments. By using molecular sieves, the water in formic acid is removed, and the yield of the desired (Z)-1-phenylpropene product increases to the highest value (86%) in 5 hours but decreases to 54% when the reaction is run for 16 hours due to the further Z → E isomerization and hydrogenation. In the second stage which starts from (Z)-1-phenylpropene, the yield of (E)-1-phenylpropene decreased from 90% (with 4 A MS) to 67% in the aqueous solution of formic acid.

The lanthanide tetrad effect and Y-Ho fractionation are commonly observed in highly fractionated melts. In pegmatites, they are attributed to liquid immiscibility, although this explanation has recently been debated. Based on the potential relationship between the lanthanide tetrad effect and liquid immiscibility in pegmatite-forming melts, the rare earth element compositions (REEs, including Y) in three types of zircons from the magmatic stage (Zone II), magmatic-hydrothermal transition stage (Zones III and V) and hydrothermal stage (Zone VI) of the Kelumute No. 112 pegmatite, Chinese Altai, were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in this study. The results show that the REEs are sharply fractionated from the magmatic stage to the hydrothermal stage. According to the REE variations in the three types of zircons that formed during different stages and the evidence from inclusions, the intense lanthanide tetrad effect and suprachondritic Y/Ho ratios in zircons from Zones III, V and VI result from selective incorporations of REEs in immiscible fluoride melt, which generated the W-type tetrad effect and subchondritic Y/Ho ratios in the fluoride melt and the complementary M-type tetrad effect and suprachondritic Y/Ho ratios in the coexisting silicate melt and aqueous fluid. The results further reflect that the liquid immiscibility of the silicate melt, fluoride melt and aqueous fluid occurred during the magmatic-hydrothermal transition stage of the pegmatite-forming melt. In addition, for the first time, a negative Ce anomaly was identified in the terrestrial zircon from Zone VI of the No. 112 pegmatite; this anomaly is attributed to the preferential incorporation and/or adsorption of Ce in/by the Fe-Mn oxyhydroxides prior to or during the crystallization of zircon in the hydrothermal stage.

A Cu-catalyzed cascade oxidative radical process of β-keto sulfones with alcohols has been achieved by using oxygen as an oxidant. In this reaction, β-keto sulfones were converted into sulfinate esters under the oxidative conditions via cleavage of C-S bond. Experimental and computational studies demonstrate that a new pathway is involved in this reaction, which proceeds through the formation of the key four-coordinated CuII intermediate, O-O bond homolysis induced C-S bond cleavage and Cu-catalyzed esterification to form the final products. This reaction provides a new strategy to sulfonate esters and enriches the research content of C-S bond cleavage and transformations.

The mechanism of tandem dimethylamine-borane (NHMe2BH3, DMAB) dehydrogenation and alkene hydrogenation catalyzed by [Pd(NHC)(PMe3)] are investigated by density functional theory (DFT) calculations [NHC = N,N′-bis(2,6-diisopropylphenyl) imidazole-2-ylidene]. Four possible DMAB dehydrogenation mechanisms have been carefully investigated involving concerted B H/N H activation, sequential B H/N H activation, sequential N H/B H activation, and proton transfer mechanism. DFT studies show that the N H proton transfers to ligated carbene carbon and sequential C H/B H activation is the most kinetically favorable pathway with the lowest activation barrier of 23.8 kcal/mol. For hydrogenation, it was found that a trans-dihydride Pd(II) complex, [Pd(H)2(NHC)(PMe3)], formed in the dehydrogenation process, serves as an effective catalyst for reduction of trans-stilbene.

The joint computational and experimental efforts reveal that the organic molecule 1,2-diisocyano-4,5-dimethylbenzene (1) acts as both a reactant and a photosensitizer (PS) in a metal-free reaction with perfluoroalkylhalide (2) to produce 2-perfluoroalkyl quinoxalines (3) under visible light. Both the π-π stacking aggregation in crystals and the solvation in various solvents of PS 1 exhibited visible-light absorption at 466 nm in spite of its smaller coefficient than that of the ultraviolet-light absorption. Such an aggregation-assisted visible-light absorption phenomenon is rationalized by theoretical calculations of the condensed-phase properties with the consideration of the explicit polarization effect from the neighboring molecules. Upon irradiation with different wavelengths, the emission colors changed from navy to bright yellow. Fluorescence lifetime measurements show that the emission of 1 comes from its singlet excited state. The aggregation induced emission when excited at 420 nm has a shorter lifetime (0.45 ns) than that of the emission from isolated molecules (2.71 ns) when excited at 381 nm. It is conceived that the aggregation assisted visible light absorption properties may be general in other photo-reactive molecules, such as 1,4-diisocyano-2,5-dimethylbenzene (4), 1,4-dicyanobenzene (5), and 1,4-diisocyanobenzene (6), which are widely used in many photochemical reactions in the absence of any external photosensitizer.

A quantum-chemical mechanistic investigation using density functional theory (DFT) on ammonia-borane dehydrogenation catalyzed by a series of iron bis(phosphinite) pincer complexes is reported. A metal-ligand cooperation mechanism has been proposed, in which the hydrogen atom of B H moves to metal Fe and proton of N H transfers to pincer ipso carbon simultaneously with the lowest activation barriers. DFT calculations and natural bond orbital (NBO) charge analysis suggest that Fe POCOP complex with an electron-donating MeO group at the para position to the ipso carbon exhibits the highest catalytic activity. A plausible explanation of the observed catalytic activities is also given.

The interaction between monolayered arsenene and fourteen kinds of solvents is found to be correlated with the extent of charge transfer from arsenene to the solvents by density functional theory calculations. Among them, three kinds of aprotic solvents (cyclohexane, tetrahydrofuran and chloroform), representing different adsorbability with arsenene, were selected to exfoliate bulk arsenic crystals into nanosheets in experiments. The as-prepared concentrations of the three dispersions vary monotonically with the calculated adsorption energies and charge transfer per contact area. Transmission electron microscopy (TEM) characterization and size distribution analyses manifested that the lateral size distributions of the exfoliated arsenic nanosheets ranged from 100 nm to 1050 nm. This strategy shows the potential usage in liquid-phase exfoliation of multi-layered materials due to the interaction effects between the solvents and the surface of the materials.

Several chiral BINOL-derived bisoxazoline (BOX)/copper(II) complexes were synthesized and evaluated as catalysts for the Friedel–Crafts reaction of indoles with isatin-derived β,γ-unsaturated α-keto esters. The resulting bis-indole products bearing a quaternary stereocenter were obtained in excellent yields and enantioselectivities. Additionally, the desired products were practically transformed to α-amino esters, α-hydroxy esters and α-keto amides. It is noteworthy that this catalytic procedure was conducted with a catalyst loading of 0.5 mol% without any discernible decrease in the reactivity or enantioselectivity.

One peculiar type of aza-hetero-imidazolidinyl spirooxindole derivatives was efficiently constructed by the three-component [2+2+1] cascade reaction of 1,4-oxazepines with diazo-oxindoles. Iron(II) trifluoromethanesulfonate [Fe(OTf)2] or p-toluenesulfonic acid monohydrate (p-TsOH⋅H2O) proved to be optimal catalysts for this transformation, providing the desired products in high yields (up to 94 %) with excellent diastereoselectivity (up to 99:1 dr). Experimental studies showed that the reaction rate of Bronsted acid catalysis was faster than that of Lewis acids. Furthermore, the mechanism was theoretically investigated for Bronsted acid as the catalyst and a reaction pathway was proposed. DFT calculations suggested that the diazo-oxindole can act as a 1,3-dipole to add to a C=N double bond of 1,4-oxazepine, which forms a 4,5-dihydro-1H-1,2,3-triazole intermediate. Subsequently, the releasing of N2 is the rate-limiting step of the whole catalytic cycle.

The possible transition states of C–H activation on the dehydrogenate coupling of arenes with alcohols employing Ag(I) additives were investigated using B3LYP density functional theory. The AgOTf salt with Cu(OAc)2 was identified as the most active catalyst. The facile occurrence of the studied reactions is supported by the low activation energies of their respective transition states.

The present paper describes the development of in-ring reaction measurements at the Cooler-Storage Ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). A Silicon (Si) detector has been developed with cost-efficient methods to meet the requirements of Ultra-High Vacuum (UHV) conditions in a storage ring. The UHV-Si detector and luminosity monitor Si(Li) detector were installed at the experimental cooler storage ring (CSRe). The pilot in-ring reaction experiment about proton elastic scattering on 58Ni 19 + ions has been operated successfully with the basic detector system in inverse kinematics , which opens an opportunity for in-ring reaction measurements at the HIRFL-CSR. This is an important step towards realizing in-ring reaction measurements with large Si detector arrays at the next generation High Intensity heavy ion Accelerator Facility (HIAF).

Isochronous mass spectrometry was applied to measure isomeric yield ratios of fragmentation reaction products. This approach is complementary to conventional gamma-ray spectroscopy in particular for measuring yield ratios for long-lived isomeric states. Isomeric yield ratios for the high-spin I = 19/2 states in the mirror nuclei 53Fe and 53Co are measured to study angular momentum population following the projectile fragmentation of 78Kr at energies of 480A MeV on a beryllium target. The 19/2 state isomeric ratios of 53Fe produced from different projectiles in the literature have also been extracted as a function of mass number difference between projectile and fragment (mass loss). The results are compared to ABRABLA07 model calculations. The isomeric ratios of 53Fe produced using different projectiles suggest that the theory underestimates not only the previously reported dependence on the spin but also the dependence on the mass loss., Comment: 6 pages, 5 figures

Possible mechanisms of copper-catalyzed N–H/C–H activation from N-phenylbenzamidine to 2-phenylbenzimidazole have been investigated using density functional theory (DFT) calculations. In comparison with the C–H activation mechanism, the N–H/C–H activation with a Cu-assisted concerted metalation–deprotonation (CMD) mechanism is found to be more kinetically favorable. Facile occurrence of the studied reactions is supported by the low activation energies of their respective rate-determining steps. A possible alternative mechanism involving a Cu–H agostic transition state is presented, but it is unfavored by the relatively higher activation barriers.

Computational studies have been performed to elucidate the activation mechanism of the Michael addition reactions containing bifunctional tertiary amine–thioureas and isatylidene malononitriles by density functional theory (DFT) calculations at the B3LYP/6-311++G(d,p)//B3LYP/6-31G(d) level of theory. Results showed a difference of 6.47 kcal mol−1 between M1-O and M1-N, which suggest that it is the carbonyl group, instead of the malononitrile moiety of isatylidene malononitriles, that plays a dominating role in the activation of the electrophile by the catalysts. The predicted mechanism also successfully explains the experimentally observed enantioselectivity.

A theoretical understanding of the Pd-catalyzed C(sp3)–H activation of aliphatic amines has been examined using the B3LYP density functional theory. The concerted metalation–deprotonation (CMD) mechanism is identified in the rate-determining steps of all possible reaction pathways. The rate- and regio-determining step of the catalytic cycle is deprotonation of the Cmethyl–H bond through a six-membered cyclopalladation transition state. According to the relative activation barriers, the Cmethyl–H activation is kinetically and thermodynamically more favorable than the Cethyl–H activation. More important, the only acetoxylation product is located, ignoring the diethyl-substituted or the dimethyl-substituted in the morpholine and not producing the lactone amines molecules, which is in good agreement with the experimental observations.

A formal thio [3 + 3]-cyclization catalyzed by a DPEN-derived chiral thiourea has been reported for the construction of optically active thiopyrano-indole annulated heterocyclic compounds in high yields with excellent enantioselectivities. The high reactivity between indoline-2-thione (keto-S) and 2-benzylidenemalononitrile has also been supported by density functional theory (DFT) calculations.

The catalytic dehydrogenation of ammonia borane (NH 3 BH 3 ) with the Ir pincer complex, [Ir(I t Bu′) 2 ] + , has been investigated by density functional theory (DFT). A mechanism has been proposed for dehydrogenation process involving three possible pathways: stepwise B–H/N–H activation, concerted B–H/N–H activation and proton transfer mechanism. The facile occurrence of the studied systems was demonstrated by the activation barriers of the rate-determining steps. It was found that the proton transfer pathway is mostly kinetically favorable with the lowest activation barrier of 28.38 kcal/mol.

The origin of the enantio- and regioselectivity of ring-opening reaction of oxabicyclic alkenes catalyzed by rhodium/Josiphos has been examined using M06-2X density functional theory(DFT). DFT calculations predict a 98% ee for the enantioselectivity and only the 1,2-trans product as one regio- and diastereomer, in excellent agreement with experimental results. The solvent tetrahydrofuran(THF) plays a key role in assisting nucleophilic attack. Orbital composition analysis of the LUMO and the NPA atomic charge calculations were conducted to probe the origins of the regioselectivity. The orbital composition analysis reveals two potential electrophilic sites of the Rh–π-allyl intermediate M3 and the NPA atomic charges demonstrate that Cα carries more positive charges than Cγ, which suggests that Cα is the electrophilic site.

Pyranonaphthoquinone units are common in molecular structures with significant biological and pharmaceutical activities. Herein, the organocatalytic asymmetric cascade Michael cyclization reaction of 2-hydroxynaphthalene-1,4-diones to isatylidene malononitriles has been developed, which provided the desired spiro[4H-benzo[g]chromene-indoline] derivatives in up to 99% yield with up to 99% ee. To illustrate the potential utility of these products, a further transformation was conducted to give a spiropoly­heterocyclic compound in moderate yield without loss of enantioselectivity (>99% ee). Biological evaluation of these spiro[benzo[g]chromene-indoline] derivatives has revealed excellent antiproliferative activity against a number of cancer cell lines, with a high inhibition rate ranging from 93% to 99% at a concentration of 50 μM.

A gas-filled recoil separator, SHANS (Spectrometer for Heavy Atom and Nuclear Structure), constructed at the Institute of Modern Physics in Lanzhou is reported. With the QDQQ magnetic configuration, where D and Q denote the dipole and quadrupole magnets respectively, the apparatus is used to study the heavy nuclei produced in the heavy-ion-induced fusion reactions. The helium gas is filled in the field region of the separator at a pressure of about 1 mbar. The maximum magnetic rigidity of the dipole magnet is 2.9 Tm. With the commissioning of the device, the performance of the separator in several fusion evaporation reactions is investigated.

Nitrogen (N)-doped zinc oxide (ZnO) particles were successfully synthesised by a simple and economical ammonia-assisted hydrothermal method. The samples were characterised by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and ultraviolet–vis diffuse reflectance. It was found that N-doped ZnO exhibited higher photocatalytic activity than commercial Degussa P25 towards the liquid-phase degradation of Rhodamine B and methylene blue under simulation of solar light. The authors attribute these results to enhanced visible-light absorption ability and efficient separation of photogenerated carriers. The authors hope that this study provides valuable information on the design of specific ZnO photocatalytic materials for further industrial application.

It is in great request to substitute foamed concrete for organic thermal insulating materials that are inflammable and liberate virulent gases on burning. In current study, felsite powder (powdery magnetite mill tailings) was used as filler and Solvay distiller waste (DW) was used as hardening accelerator for foamed concrete. The results showed that the strength and strength-to-density ratio of foamed concrete in cement-felsite powder system is much higher than those in cement-sand system and cement-lime-sand system. The Solvay distiller waste, suspending agent and polypropylene fiber can improve performances of foamed concrete such as cohesion and strength. DW can reduce shrinkage in forming process of foamed concrete.

In production of manufactured fine aggregate (MFA) from magnetite mill tailings (MT), the micro fines (particles smaller than 75 microns) was strictly eliminated. This results in lower utilization of the resources and worse micro grading of MFA. The mortar samples were prepared with MT at various micro fines contents to investigate the effects on their fluidities and strengths. In optimal water-to-powder ratio (w/p, all powders included), the fluidities of mortars reached maximum and the strengths of mortars could be improved at suitable content of micro fines in MFA. The application proves that MT can be used as MFA to prepare construction mortars up to standard and micro fines can be substituted for mineral admixture to prepare composite mortars for improving workability. So more MT can be utilized and micro fines in the tailings can take effect.

The discarded mill tailings behind the dam will cause disasters at any time. A solution to this problem may be to utilize those wastes, e.g. mill tailings from magnetite, as the Manufactured Fine Aggregates (MFA) for preparation of concretes. The mill tailings from magnetite can be considered as new resources of sand. However, in production of MFA from mill tailings, the particles smaller than 75 μm were strictly eliminated. The degranulation results in not only lower utilization of the resources but also worse micro grading of MFA. The micro fines, i.e. powdery mill tailings from magnetite, supplements powder content in concrete systems in w/c>0.40 to modify the ratio of water to total powder (w/p). The perfect micro grading for good workability can be reached in the case of optimal w/p ratio. The filling effect owing to perfect micro grading of powdery mill tailings makes concretes more compact and the pozzolanic constituents in micro particles of the tailings contribute to the strength of concretes.

A series of chiral thiopyrano-indoles (III) and (V) is readily obtained by an enantioselective cyclization of indoline-2-thiones (I) with dinitriles (II) and (IV).

A diastereo- and enantioselective domino Michael-cyclization-tautomerization reaction of isatylidene malononitriles (I) and (IV) with α,α-dicyanoalkenes catalyzed by a chinchona alkaloid-derived bifunctional catalyst is reported.

Pyranonaphthoquinone units are common in molecular structures with significant biological and pharmaceutical activities. Herein, the organocatalytic asymmetric cascade Michael cyclization reaction of 2-hydroxynaphthalene-1,4-diones to isatylidene malononitriles has been developed, which provided the desired spiro[4H-benzo[g]chromene-indoline] derivatives in up to 99% yield with up to 99% ee. To illustrate the potential utility of these products, a further transformation was conducted to give a spiropoly­heterocyclic compound in moderate yield without loss of enantioselectivity (>99% ee). Biological evaluation of these spiro[benzo[g]chromene-indoline] derivatives has revealed excellent antiproliferative activity against a number of cancer cell lines, with a high inhibition rate ranging from 93% to 99% at a concentration of 50 μM.

Strong odd-even staggering (OES) of the yields of fragments, produced by fragmenting Kr78 projectiles, has been measured by employing the combination of an in-flight fragment separator and a storage ring. It is shown that the OES of fragment yields of Tz=−1/2 and Tz=1/2 mirror nuclei critically depends on both pairing and shell structure, especially at the closed shells Z=20 and 28. A comparison of the relative OES of yields and of particle-emission threshold energies reveals unambiguously that the origin of the OES of fragment yields is mainly determined by the OES of the particle-emission threshold energies, which contain both pairing and shell effects.

Proton nuclear magnetic resonance (1H-nmr) techniques have been used for the determination of the molar substitution (MS) of hydroxypropyi cellulose. The method for measuring MS was based on the hydrolysis of hydroxypropyi cellulose with concentrated deuteriochloric acid (DC1) and integration of area of the nmr peaks of the hydrolyzed product. The results obtained by the proposed nmr method agreed well with those provided by the chromic acid oxidation distillation method. Furthermore, according to the established relationship between average MS and the content of hydroxypropyi group (HC), the MS of hydroxypropyi cellulose was also calculated, and therefore further verifying the accuracy of the nmr data.

The {beta}-decay of {sup 18}N has been studied using {beta}-n and {beta}-{gamma} coincidence methods. The {sup 18}N ions were produced by the fragmentation of the E/A=68.8 MeV {sup 22}Ne beam on a thick beryllium target. A newly constructed neutron detector system with wide energy detection range and low-energy detection threshold was used. The 619 {+-} 2 ms half-life of the {sup 18}N {beta}-decay was found to be in very good agreement with the previous measurements. Transitions to 11 {beta}-delayed neutron emitting states in {sup 18}O have been observed with a total branching ratio of 6.98 {+-} 1.46%. The Gamow-Teller {beta}-decay strengths of {sup 18}N to these levels were deduced and compared with the shell model calculations. The intensities of the strong {gamma}-ray transitions in {sup 18}O were found to be consistent with recent work.

A diastereo- and enantio-selective domino Michael-cyclization-tautomerization reaction of isatylidene malononitriles with α,α-dicyanoalkenes catalyzed by a cinchona alkaloid-derived bifunctional thiourea catalyst has been developed. A series of multi-functionalized spiro oxindole diene derivatives have been obtained in good to excellent yields (up to 97%) with good to excellent enantioselectivities (up to 96%) as well as good diastereoselectivities (up to 7.9 : 1). In addition, an anomalous temperature effect on the enantioselectivity has also been studied for this transformation.

Via a reconsideration of a simple model for bipolarons we have shown that in order to keep the total energy of the model system being a stable minimum a new phonon coherent state should be introduced as a result of the electron-phonon interaction. Thus it could be infered that the reduction effect of phonons is much weaker and the range of the singlet bipolaronic state as the stable ground state configuration is more extensive that what the previous authors considered.

Via a reconsideration of a simple model for bipolarons, we have shown that in order to-keep the total energy of the model system to be a stable minimum, a new phonon coherent state should be introduced as a result of the electron-phonon interaction. Thus it could be in-fered that the reduction effect of phonons is much weaker and the range of the singlet bipo-laronic state as the stable ground state configuration is more extensive than what the previous authors considered.