State Key Laboratory for Physical Chemistry of Solid Surfaces Xiamen University,China

I.Introduction The State Key Laboratory for Physical Chemistryof Solid Surfaces(SKLPCSS),located in Xiamen Uni-versity,announced its establishment in 1987.The lab-oratory has 33 faculty members including 26 researchfellows(5 members of CAS),2 administrators and 4technicians.The Academic Committee consists of 16Chinese physical chemistry experts.     

The Occurrence of Pesticides in Groundwater—Results of Case-studies

Abstract

A comparative review of pesticide survey endosing 16 waterworks in the FRG tries to increase the understanding about interferences of pesticide utilization and pesticide occurrence in ground- and drinkingwater, which includes characterization of sampling points, subsurface situation, land use and pesticide application. Between 1986 and 1991, 5772 samples were measured and led to 219094 data about the occurrence of various pesticides. 5% of these analyses showed pesticide or metabolite concentrations above the particular detection limits. This result does not vary in large extent considering groups of different characterized sampling points like groundwater dominated or surface water sampling points. As the herbicide atrazine and its metabolite desethylatrazine as well as the herbicide simazine were detected most often in all samples independent whether considering groundwater und surface water samples, this fact confirms the FRG-application ban for atrazine as well as the application restriction for simazine.     

Influence of Soil Moisture and Vegetation on Climate (Ⅱ)——Numerical Experiments on Persistence of Short-term Climatic Anomalies

Numerical experiments on the influence of soil moisture and vegetation on the persistence of short-term climatic anomalies are performed with a vertical one-dimensional climate model in the atmosphere-soil-vegetation system.The experimental results indicate that, as shown by theoretical analysis in Part Ⅰ of this paper,soil hydrology is crucially important for maintenance of short-term climatic anomalies over land areas. Possible physical process concerned with impact of soil moisture and vegetation on the persistence is further discussed.     

Sensitivity—enhanced Experiments for the Measurement of J and Dipolar Coupling Constants

A sensitivity-enhanced IPAP NMR experiment was described in this paper,which separates the ^1H-^15N doublets into two different spectra to alleviate the problem of resonance overlaps and achieve the accurate measurement of J and residual dipolar coupling constants in proteins.This experiment offered 20%-60% sensitivity enhancement over the original IPAP experiment,and therefore produced more measurable resonances.Pulsed field gradient was used for coherence selection.Water-flip-back approach was used for water suppression.The sensitivity-enhanced IPAP experiment was employed in the measurement of ^1JNH and ^1DNH constants of the protein UBC9.     

Separation of Epigallocatechin Gallate from Natural Plant Extracts Using Crowding Agents—Assisted Imprinted Polymers

A methodology-based molecularly imprinted polymer (MIP) was proposed to separate epigallocatechin gallate (EGCG) from natural plant extracts. A molecular crowding agent was introduced to improve the affinity and recognizing ability of EGCG in the preparation of an MIP monolith. Acrylamide was used as the functional monomer, and ethylene glycol dimethacrylate was the crosslinking monomer, using a solution of polystyrene in tetrahydrofuran as a molecular crowding agent with isooctane as a coporogen. In addition, it was found that the ratio of the macromolecule agent, the amount of templates and crosslinking degree, and the composition of the mobile phase greatly affected the retention of the template and performance of molecular recognition. The imprinting factor of the resulting MIP monolith obtained was up to 9.67. The resulting MIP can be used to purify EGCG from crude tea polyphenol efficiently with mean recoveries of 87.42 %.

     

Structures and Structural Evolution of Sublayer Surfaces of Metal–Organic Frameworks

The structural characterization of sublayer surfaces of MIL-101 is reported by low-dose spherical aberration-corrected high-resolution transmission electron microscopy (HRTEM). The state-of-the-art microscopy directly images atomic/molecular configurations in thin crystals from charge density projections, and uncovers the structures of sublayer surfaces and their evolution to stable surfaces regulated by inorganic Cr₃(μ₃-O) trimers. This study provides compelling evidence of metal–organic frameworks (MOFs) crystal growth via the assembly of sublayer surfaces and has important implications in understanding the crystal growth and surface-related properties of MOFs.     

Adsorption and Vibration of O on the Pt Stepped Surfaces

1 INTRODUCTION Atom adsorption on transition metal surfaces has attracted special attention as a basis for understand- ing the fundamental processes of oxidative cataly- sis. An oxygen-covered platinum surface for example, plays a central role in several important reactions, such as oxidation of carbon monoxide[1]. Moreover, the behavior of oxygen in the proximity of surface defects like kinks and steps is a central issue in understanding the chemisorption processes on ca- talytic surfaces…     

Adsorption and Vibration of CI Atoms on Ni Low-index Surfaces

The 5-parameter Morse potential（5-MP） of the interactions between Cl atoms and Ni surfaces was constructed. The adsorption and diffusion of Cl atoms on Ni low index-surfaces were investigated with 5-MP in detail. All the critical characteristics of the system, such as adsorption site, adsorption geometry, binding energy, eigenvalues for vibration, etc. were obtained. The calculated results show that chlorine atoms are likely to be adsorbed on the high symmetry- sites. Cl atoms locate on the four-fold hollow sites of the intact Ni（100） surface, while they tend to occupy threefold sites on the Ni（ 111 ） surface. The four-fold hollow sites are the most stable adsorption sites on the Ni （110） surface for Cl, although the three-fold sites and the long-bridge sites are stable adsorption sites on the Ni（110） surface for the atoms of the first and second periods. For the Cl-Ni surface adsorption system, the surface binding energy of a Cl atom is relevant to the coarse degree of the cluster surface, and the binding energies have an order of Ni （ 111 ） 〈 Ni（100） 〈Ni（100）.     

Studies on Volatilization of Zirconium from Electrothermal Graphite Furnace for Sample Introduction into Inductively Coupled Plasma

Element zirconium reacted with polytetrafluoroethylene (PTFE) dispersed in isopropanol-water mixture to form volatile fluoride when heated in an electrothermal graphite furnace, and the fluorides formed subsequently were vaporized into ICP for atomization and excitation. The technique provides a picogram detectkm limit and adequate precision of 4% relative standard deviation. Linear dynamic range covers over three orders of magnitude. The process of sample preparation it very convenient. It is expected that the method proposed is suitable for determination of other refractory elements.     

Organochlorine Pesticides and PCBs In Tissues from Dutch Citizens (1968–1986)

Abstract

Adipose tissue, milk and blood from Dutch citizens have been investigated for the occurrence of organochlorine compounds since 1968. In this paper, median values for HCB, α-HCH, β-HCH, γ-HCH, β-Hepo (heptachlorepoxide), dieldrin, p.p′-DDE, o.p′-DDT, TDE and PCBs (first determined by the perchlorination method, later by a selection of individual congeners) are given. Time trends, influence of age and sex of the donors, changes in concentrations of milk during lactation, the possible effect of life-style, and statistical evaluation of the data collected over the past twenty years will be discussed.

PCBs and p.p′-DDE occur in the highest concentrations in all tissues investigated, followed by HCB and β-HCH. Especially the p.p′-DDT levels decreased dramatically over the years of the investigation. Blood/fat accumulation factors were derived; they decrease in the order PCBs?p.p′-DDE >β-HCH?HCB > β-Hepo?dieldrin > α-HCH?γ-HCH.     

Report On ‘Water Chemistry: Using Field and Laboratory Experiences to Teach Scientific-Thinking Skills’

A new curriculum involving a blended general and organic chemistry course is being introduced at San Jose State University this fall by Stephen Branz and Maureen Scharberg. They shared their experiences in creating this new curriculum and described how they overcame resistance to this change from the university community to the workshop participants. The participants of the workshop then had the opportunity to examine the new curriculum and consider how they would approach problems in both the planning and implementation phase of such a project. The workshop participants created a final list of pros and cons for the planning stage (content, pedagogy, and transportability) and a list of possible strategies for the implementation stage (marketing, resources, and logistics).     

Metabolite Profiling of In Vitro Cultured and Field Grown Rhizomes of Acorus calamus from Mongolia Using GC–MS

Acorus calamus (sweet flag) is used in the traditional Chinese and Indian medicines for various ailments. Due to its extensive use in herbal medicine, natural resources from the world’s forests are being depleted at an alarming rate. In the present study, an in vitro cell culture technique is being explored as an alternative to field grown A. calamus with respect to the metabolite profile, antioxidant properties, total phenol, and total flavonoid content. Gas chromatography mass spectrometry (GC–MS) was utilized to compare the metabolite profiling between methanolic extracts of in vitro and field grown rhizome tissues of A. calamus. A statistical analysis indicated an upregulation of α-selinene, which is representative of sesquiterpene ketones, and a cyclic polyol, d-pinitol, which has an insulin mimicking effect in the in vitro cultivated rhizome tissue when compared to field grown rhizomes. Significantly higher free-radical scavenging activity (IC₅₀ 69.32 μg mL⁻¹), total phenolic content (71.60 mg GAE g⁻¹), and total flavonoid content (42.34 mg CE g⁻¹) were observed in in vitro rhizome tissues compared with those from field grown rhizomes. These observations suggest that the in vitro cultivation of Acorus rhizomes could be exploited as an alternative to field grown A. calamus, as it is an endangered medicinal plant. The production of useful metabolites by the in vitro cultured rhizomes can be explored successfully for utilization by various food and drug industries.

     

Comparative Antioxidant Study of Stem and Stem Induced Callus of Phyllanthus fraternus Webster—An Important Antiviral and Hepatoprotective Plant

Phyllanthus fraternus is widely used in the cure of various liver diseases and possess antiviral properties especially against hepatitis virus. In the present study, evaluation of the antioxidant activity of stem and calli induced from stem has been done by different assays. Extraction was done by standard method in water and ethanol. Total antioxidant capacity was measured by 1, 1-diphenyl-2-picrylhydrazyl free radical scavenging method. Lipid peroxidation was measured in terms of thiobarbituric acid-reactive substances (TBARS) by using egg yolk homogenates as lipid-rich media, and superoxide radical scavenging activity was measured using riboflavin–light–nitro blue tetrazolium assay. Reducing power was determined on the basis of Fe³⁺–Fe²⁺ transformation in the presence of the extract. In addition to the antioxidant activity, polyphenolic compounds like total phenolics and flavonoids were also measured by spectroscopic method. Results showed that the ethanolic extract of stem is more potent in antioxidant activity than its aqueous extract and ethanolic extract of calli. A significant correlation between antioxidant capacity and polyphenolic content and reducing potential was observed, indicating that phenolic compounds and reducers present in extract are major contributors to the antioxidant potential. Thus, this plant extract could be used as a potent natural antioxidant.     

Degradation of Polylactide—Polyethylene Binary Blends in Soil

Russian Journal of Applied Chemistry - Binary polylactide-low-density polyethylene blends of various compositions were prepared, and their biodegradability in soil and water absorption kinetics at...     

Construction and Properties of Sierpiński Triangular Fractals on Surfaces

Fractal structures are of fundamental importance in science, engineering, mathematics, and aesthetics. Construction of molecular fractals on surfaces can help to understand the formation mechanism of fractals and a series of achievements have been acquired in the preparation of molecular fractals. This review focuses on Sierpiński triangles (STs), representatives of various prototypical fractals, on surfaces. They are investigated by Monte Carlo simulations and ultra-high vacuum scanning tunneling microscopy. STs are bonded through halogen bonds, hydrogen bonds, metal-organic coordination bonds and covalent bonds. The coexistence of and competition between fractals and crystals are realized for a hydrogen-bonded system. Electronic properties of two types of STs are summarized.