Spatiotemporal Evaluation of Water Quality and Hazardous Substances in Small Coastal Streams According to Watershed Characteristics.

In this study, spatial and temporal changes of eight water quality indicators and 30 types of hazardous substances including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, and inorganic matters for the small coastal streams along the West Coast of South Korea were investigated. In coastal streams with clear seasonal changes in water quality, larger watershed areas led to greater contamination by particulate matter (i.e.

Time-resolved resonant elastic soft x-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser.

Resonant elastic x-ray scattering has been widely employed for exploring complex electronic ordering phenomena, such as charge, spin, and orbital order, in particular, in strongly correlated electronic systems. In addition, recent developments in pump-probe x-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL).

Water-repellent Hybrid Nanowire and Micro-scale Denticle Structures on Flexible Substrates of Effective Air Retention.

The air retention capability of a superhydrophobic surface plays the crucial role of drag reduction in an aqueous environment. Here, fabrication of water-repellent hybrid structural surfaces by synthesizing superhydrophobic nanowires with a high aspect ratio on micro-scale denticle structures to improve their air holding capacity in water is reported. The hybrid structure is realized by carrying out polymer molding of denticle structures on flexible substrates, hydrothermal growth of nanowires, and subsequent ultra-thin film coating.

PAL-XFEL soft X-ray scientific instruments and X-ray optics: First commissioning results.

We report an overview of soft X-ray scientific instruments and X-ray optics at the free electron laser (FEL) of the Pohang Accelerator Laboratory, with selected first-commissioning results. The FEL exhibited a pulse energy of 200 μJ/pulse, a pulse width of <50 fs full width at half maximum, and an energy bandwidth of 0.44% at a photon energy of 850 eV.

A cross-sectional study on the association between vitamin D levels and caries in the permanent dentition of Korean children.

Background: A recent study in Canada reported that vitamin D deficiency is associated with dental caries. Because Koreans have been reported to be deficient in vitamin D, we investigated the relationship between dental caries and reduced serum vitamin D levels in Korean children. The purpose of this study was to analyze the relationships between blood vitamin D [25(OH)D] concentrations and dental caries in the permanent dentition of Korean children.

Association of dental caries with socioeconomic status in relation to different water fluoridation levels.

Objectives: The aim of this study was to assess the prevalence of dental caries in 11-year-old children, related to water fluoridation and family affluence scale (FAS), as an indicator of socioeconomic status (SES) in Korea.

Methods: A total of eight areas were selected for study: four areas with fluoridated piped water (WF areas) and four areas with nonfluoridated piped water (non-WF areas). Non-WF areas had a similar economic level and population size compared with the WF areas.

Systemic effect of water fluoridation on dental caries prevalence.

Objectives: The aim of this study was to evaluate the systemic effect of water fluoridation on dental caries prevalence and experience in Cheongju, South Korea, where water fluoridation ceased 7 years previously.

Methods: A cross-sectional survey was employed at two schools where water fluoridation had ceased (WF-ceased area) and at two schools where the water had never been fluoridated (non-WF area). The schools in the non-WF area were of a similar population size to the schools in the WF-ceased area.

Methane sorption and structural characterization of the sorption sites in Zn2(bdc)2(dabco) by single crystal X-ray crystallography.

Sorption isotherms of methane in Zn(2)(bdc)(2)(dabco) are measured up to a pressure of 35 bar in the temperature range between 198-296 K. The methane sorption measurements at 296 K showed an uptake of 137 cm(3) cm(-3) at 35 bar. The enthalpy of methane adsorption for Zn(2)(bdc)(2)(dabco) estimated by the virial equation is 13.

The effect of hydrodynamic flow regimes on the algal bloom in a monomictic reservoir.

The effectiveness of a proposed curtain weir to be installed in the transitional zone of a eutrophic reservoir located in monsoon areas on the control of algal blooms in the lacustrine zone where drinking water withdrawals occur was assessed with various hydrodynamic flow regimes. A two-dimensional hydrodynamic and eutrophication model that can accommodate vertical displacement of the weir following the water surface changes was developed and validated using field data obtained from two distinctive hydrological years; drought (2001) and wet (2004). The model adequately reproduced the temporal and spatial variations of temperature, nutrients and phytoplankton concentrations in the reservoir.

Microporous magnesium and manganese formates for acetylene storage and separation.

Acetylene sorption of microporous metal formates M(HCOO)2 (M = Mg and Mn) was investigated. Measurements of acetylene sorption at 196, 275, and 298 K showed a Type I isotherm with quick saturation at low pressures, and 50-75 cm3 g(-1) uptake at 1.0 atm.

Asarum sieboldii extracts attenuate growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans.

Asarum sieboldii has been used in traditional folk medicine to treat dental caries and periodontal disease. In the present study, we investigated the inhibitory effect of the ethanol and aqueous extracts of A. sieboldii on the growth, acid production, adhesion, and water-insoluble glucan synthesis of Streptococcus mutans.

Crystallization and initial crystallographic characterization of the Corynebacterium glutamicum nitrilotriacetate monooxygenase component A.

Safety and environmental concerns have recently dictated the proper disposal of nitrilotriacetate (NTA). Biodegradation of NTA is initiated by NTA monooxygenase, which is composed of two proteins: component A and component B. The NTA monooxygenase component A protein from Corynebacterium glutamicum was crystallized using the sitting-drop vapour-diffusion method in the presence of ammonium sulfate as the precipitant.

Vapor phase inclusion of ferrocene and its derivative in a microporous metal-organic porous material and its structural characterization by single crystal X-ray diffraction.

The inclusion of ferrocene and its derivative in metal-organic porous material MOF-5 is achieved by vapor diffusion; single-crystal X-ray diffraction studies using synchrotron radiation of ferrocene-loaded MOF-5 reveal well-ordered guest molecules packed into the pores.

Structural basis for the extended substrate spectrum of CMY-10, a plasmid-encoded class C beta-lactamase.

The emergence and dissemination of extended-spectrum (ES) beta-lactamases induce therapeutic failure and a lack of eradication of clinical isolates even by third-generation beta-lactam antibiotics like ceftazidime. CMY-10 is a plasmid-encoded class C beta-lactamase with a wide spectrum of substrates. Unlike the well-studied class C ES beta-lactamase from Enterobacter cloacae GC1, the Omega-loop does not affect the active site conformation and the catalytic activity of CMY-10.

The inverted cucurbit[n]uril family.

We report the isolation, characterization, and recognition behavior of iCB[6] and iCB[7], which are diastereomers of CB[6] and CB[7], respectively, containing a single inverted glycoluril unit. Product resubmission experiments establish that these inverted CB[n] are intermediates in the mechanism of CB[n] formation. As a consequence of the inverted glycoluril ring, these inverted cucurbiturils possess a permanent dipole moment, are slightly smaller than their diastereomers, show distinctive selectivity in their recognition behavior, and report directly on the contents of their hydrophobic cavity.

Highly efficient protein expression and purification using bacterial hemoglobin fusion vector.

Recently developed bacterial hemoglobin (VHb) fusion expression vector has been widely used for the production of many target proteins due to its distinctive properties of expressing fusion protein with red color which facilitates visualization of the steps in purification, and increasing solubility of the target proteins. However, after intensive use of the vector, several defects have been found. In this report, we present a modified VHb fusion vector (pPosKJ) with higher efficiency, in which most of the defects were eliminated.

Crystal structure of bet3 reveals a novel mechanism for Golgi localization of tethering factor TRAPP.

Transport protein particle (TRAPP) is a large multiprotein complex involved in endoplasmic reticulum-to-Golgi and intra-Golgi traffic. TRAPP specifically and persistently resides on Golgi membranes. Neither the mechanism of the subcellular localization nor the function of any of the individual TRAPP components is known.

Structural double-mutant cycle analysis of a hydrogen bond network in ketosteroid isomerase from Pseudomonas putida biotype B.

KSI (ketosteroid isomerase) catalyses an allylic isomerization reaction at a diffusion-controlled rate. A hydrogen bond network, Asp(99).Water(504).

Crystallization and preliminary X-ray crystallographic analyses of CMY-1 and CMY-10, plasmidic class C beta-lactamases with extended substrate spectrum.

Plasmid-encoded class C beta-lactamases, including CMY-1 and CMY-10, hydrolyze the lactam bonds of beta-lactam antibiotics, inducing therapeutic failure and a lack of eradication of clinical isolates by third-generation cephalosporins or cephamycins. Therefore, the enzymes are potential targets for developing agents against pathogens isolated from patients suffering from wound infection, urinary tract infection or pneumonia. CMY-1 and CMY-10 were purified and crystallized at 298 K.

Crystallization and preliminary X-ray crystallographic analysis of a ytfG gene product from Escherichia coli.

The Escherichia coli ytfG gene product, with NAD(P)H:quinone oxidoreductase activity, was crystallized by the hanging-drop vapour-diffusion method at 296 K. A 1.78 A data set has been collected using synchrotron radiation at Pohang Light Source, South Korea.

Crystal structures of human DJ-1 and Escherichia coli Hsp31, which share an evolutionarily conserved domain.

Human DJ-1 and Escherichia coli Hsp31 belong to ThiJ/PfpI family, whose members contain a conserved domain. DJ-1 is associated with autosomal recessive early onset parkinsonism and Hsp31 is a molecular chaperone. Structural comparisons between DJ-1, Hsp31, and an Archaea protease, a member of ThiJ/PfpI family, lead to the identification of the chaperone activity of DJ-1 and the proteolytic activity of Hsp31.

The conserved cis-Pro39 residue plays a crucial role in the proper positioning of the catalytic base Asp38 in ketosteroid isomerase from Comamonas testosteroni.

KSI (ketosteroid isomerase) from Comamonas testosteroni is a homodimeric enzyme that catalyses the allylic isomerization of Delta5-3-ketosteroids to their conjugated Delta4-isomers at a reaction rate equivalent to the diffusion-controlled limit. Based on the structural analysis of KSI at a high resolution, the conserved cis-Pro39 residue was proposed to be involved in the proper positioning of Asp38, a critical catalytic residue, since the residue was found not only to be structurally associated with Asp38, but also to confer a structural rigidity on the local active-site geometry consisting of Asp38, Pro39, Val40, Gly41 and Ser42 at the flexible loop between b-strands B1 and B2. In order to investigate the structural role of the conserved cis-Pro39 residue near the active site of KSI, Pro39 was replaced with alanine or glycine.

Crystal structures of RbsD leading to the identification of cytoplasmic sugar-binding proteins with a novel folding architecture.

RbsD is the only protein whose biochemical function is unknown among the six gene products of the rbs operon involved in the active transport of ribose. FucU, a paralogue of RbsD conserved from bacteria to human, is also the only protein whose function is unknown among the seven gene products of the l-fucose regulon. Here we report the crystal structures of Bacillus subtilis RbsD, which reveals a novel decameric toroidal assembly of the protein.

Crystallization and preliminary X-ray crystallographic analysis of a yedU gene product from Escherichia coli.

A yedU gene product with a molecular mass of 31 kDa is a hypothetical protein with no known function. The protein was purified and crystallized at 296 K. X-ray diffraction data have been collected to 2.