Real-time monitoring of toxic components from fine dust air pollutant samples by utilizing spark-induced plasma spectroscopy.

A growing modern-day concern is fine dust air pollution that contains heavy metals and ammonium ions (NH4+) from industrial and agricultural waste sources, respectively. In the current study, the development of an innovative and effective technique for real-time, quantitative monitoring of toxic fine dust components using plasma emission spectroscopy is presented as a complement to emergency preparedness plans aimed at reducing dust pollution. A novel spark-induced plasma spectroscopic (SIPS) device that can control the frequency and magnitude of plasma was developed for the toxic pollutants in this work. SIPS utilizes an electrical discharge from a high voltage at a low current to produce plasma when the applied voltage is higher than the ambient voltage surrounding the electrodes. The detection limit of this setup was enhanced by a factor of 4.3 over laser-induced plasma spectroscopy (LIPS). This compact sensing device was used in combination with a new quantitative analytical method to measure the concentration of heavy metals and ammonia molecules in fine dust air pollution. By integrating the time-resolved plasma emission signals that were based on the plasma continuum decay time of each element, quantitative measurements of the minute changes in composition of 0.1 µg/m3 were conducted. The findings of this study could inspire future research on the use of SIPS for monitoring airborne fine dust pollutants with better sensitivity in real-time via a new quantitative analytical method.

A non-calorimetric approach for investigating the moisture-induced ageing of a pyrotechnic delay material using spectroscopies.

The degradation of thermal properties due to ageing such as burning rate and exothermic heat release are unsolved issues faced during a long-term storage of the pyrotechnic substances. Accordingly, we employed various non-calorimetric methods to investigate the thermal performance of pyrotechnic delay, which is exposed to various moisture-rich conditions at extended durations. The chemical and physical changes in the compositions of a pyrotechnic delay comprised of metal fuel (Zr-Ni alloy) and oxidants (KClO4, BaCrO4) are analysed for four different relative humidity levels using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope and laser-induced breakdown spectroscopy. The calculations using the NASA Chemical Equilibrium with Applications (CEA) software indicated that the heat of reaction for the components stored under the moisture-rich conditions is reduced by more than 50%. Unlike the conventional calorimetric analysis, the present non-calorimetric approach provided the compositional changes as well as the cause and effect of the relevant ageing process of pyrotechnic delay.

Porcine epidemic diarrhea vaccine evaluation using a newly isolated strain from Korea.

Porcine epidemic diarrhea virus (PEDV) infects pigs and causes an enteric disease that is characterized by vomiting and watery diarrhea. PEDV outbreaks have a tremendous financial impact on the worldwide pork industry. In South Korea, the incidence of PEDV has continued despite nationwide use of attenuated and inactivated vaccines, raising questions regarding the current vaccines' efficacy and the need for new vaccine development. In the present study, we isolated a new Korean PEDV epidemic strain, PED-CUP-B2014, in Vero cells. Phylogenetic analysis of the spike gene demonstrated that the PED-CUP-B2014 belongs in genogroup G2b and is close to PEDVs currently circulating in many countries including the United States, and is distinct from many current vaccine strains. Upon serial passages into Vero cells, PED-CUP-B2014 adapted to Vero cells, which was evidenced as higher virus growth in Vero cells and confirmed lower virulence in suckling piglets. The administration of the inactivated 65-passaged PED-CUP-B2014 to sows greatly increased the survival rate of their offspring and significantly reduced diarrhea severity after PEDV challenge. Higher serum/colostrum PEDV-specific antibodies and higher neutralizing titers were shown in sows vaccinated with PED-CUP-B2014 compared to unvaccinated sows or sows administered commercial PEDV vaccine. Altogether, our data demonstrated that the newly isolated PEDV strain conferred critical passive immune protection to pigs against epidemic PEDV infection.

Pectinase-treated Panax ginseng protects against chronic intermittent heat stress-induced testicular damage by modulating hormonal and spermatogenesis-related molecular expression in rats.

BACKGROUND: Elevated testicular temperature disrupts spermatogenesis and causes infertility. In the present study, the protective effect of enzymatically biotransformed Panax ginseng Meyer by pectinase (GINST) against chronic intermittent heat stress-induced testicular damage in rats was investigated. METHODS: Male Sprague-Dawley rats (4 wk old, 60-70 g) were divided into four groups: normal control (NC), heat-stress control (HC), heat-stress plus GINST-100 mg/kg (HG100), and heat-stress plus GINST-200 mg/kg (HG200) treatment groups. Each dose of GINST (100 mg/kg and 200 mg/kg) was mixed separately with a regular pellet diet and was administered orally for 24 wk. For inducing heat stress, rats in the NC group were maintained at 25°C, whereas rats in the HC, HG100, and HG200 groups were exposed to 32 ± 1°C for 2 h daily for 6 mo. At week 25, the testes and serum from each animal were analyzed for various parameters. RESULTS: Significant (p < 0.01) changes in the sperm kinematic values and blood chemistry panels were observed in the HC group. Furthermore, spermatogenesis-related molecules, sex hormone receptors, and selected antioxidant enzyme expression levels were also altered in the HC group compared to those in the NC group. GINST (HS100 and HS200) administration significantly (p < 0.05) restored these changes when compared with the HC group. For most of the parameters tested, the HG200 group exhibited potent effects compared with those exhibited by the HG100 group. CONCLUSION: GINST may be categorized as an important medicinal herb and a potential therapeutic for the treatment of male subfertility or infertility caused by hyperthermia.

Korean red ginseng improves testicular ineffectiveness in aging rats by modulating spermatogenesis-related molecules.

Korean red ginseng (Panax ginseng Meyer) is known to rejuvenate testicular effectiveness and the sperm maturation process by regulating redox proteins in aged rats. This study was performed to investigate the effect of Korean red ginseng water extract (KRG-WE) on the expression level of spermatogenesis-related key biomolecules and sex hormone receptors as well as enzymes regulating oxidation, histone deacetylation, and growth-related activities in aged rat testis. KRG-WE (200mg/kg) mixed with a regular pellet diet was administered to 12-month-old rats for 6months (KRG-AC), whereas the young (YC, 2months) and aged (AC, 12months) controls received the vehicle only. The results showed that the expression levels of spermatogenesis-related key biomolecules (inhibin-α, nectin-2, and cyclic adenosine monophosphate [cAMP] responsive element binding protein [CREB]-1), sex hormone receptors (androgen, luteinizing- and follicle-stimulating hormone receptors [AR, LHR, and FSHR, respectively]), and antioxidant enzymes (glutathione S-transferase mu [GSTm]-5, glutathione peroxidase [GPx]-4, peroxiredoxin [PRx]-3), as well as histone deactylation (silent mating type information regulation 2 homolog 1, SIRT1) and growth-related (mammalian target of rapamycin complex 1, mTORC1) molecules were significantly altered in the AC group rat testes compared with those of the YC group. However, KRG-WE treatment of the AC group significantly (p<0.05) attenuated these molecular changes. From these results, it can be concluded that long-term administration of KRG-WE significantly delayed the aging-induced testicular dysfunction.

Canola oil is an excellent vehicle for eliminating pesticide residues in aqueous ginseng extract.

BACKGROUND: We previously reported that two-phase partition chromatography between ginseng water extract and soybean oil efficiently eliminated pesticide residues. However, an undesirable odor and an unpalatable taste unique to soybean oil were two major disadvantages of the method. This study was carried out to find an alternative vegetable oil that is cost effective, labor effective, and efficient without leaving an undesirable taste and smell. METHODS: We employed six vegetable oils that were available at a grocery store. A 1-mL sample of the corresponding oil containing a total of 32 pesticides, representing four categories, was mixed with 10% aqueous ginseng extract (20 mL) and equivalent vegetable oil (7 mL) in Falcon tubes. The final concentration of the pesticides in the mixture (28 mL) was adjusted to approximately 2 ppm. In addition, pesticides for spiking were clustered depending on the analytical equipment (GC/HPLC), detection mode (electron capture detector/nitrogen-phosphorus detector), or retention time used. Samples were harvested and subjected to quantitative analysis of the pesticides. RESULTS: Soybean oil demonstrated the highest efficiency in partitioning pesticide residues in the ginseng extract to the oil phase. However, canola oil gave the best result in an organoleptic test due to the lack of undesirable odor and unpalatable taste. Furthermore, the qualitative and quantitative changes of ginsenosides evaluated by TLC and HPLC, respectively, revealed no notable change before or after canola oil treatment. CONCLUSION: We suggest that canola oil is an excellent vehicle with respect to its organoleptic property, cost-effectiveness and efficiency of eliminating pesticide residues in ginseng extract.

Feasibility of FRAX for Prediction of Osteoporotic Vertebral Fractures in Korea.

STUDY DESIGN: Retrospective study. PURPOSE: To assess the feasibility and limitations of fracture risk assessment tool (FRAX) for osteoporotic vertebral fractures in the Korean population. OVERVIEW OF LITERATURE: The FRAX algorithm is country specific and uses clinical risk factor data to calculate an individual patient's 10-year probability of hip fracture and 10-year probability of major osteoporotic fracture. However, it has not been adequately investigated for Korean. METHODS: ONE HUNDRED NINETY FOUR PATIENTS WHO HAD ALL RISK FACTOR DATA FOR THE CALCULATION OF FRAX WERE DIVIDED INTO TWO GROUPS DEPENDING ON THE EXISTENCE OF VERTEBRAL FRACTURES: the fracture group was comprised of 88 patients and the non-facture group comprised of 105 patients. We analyzed prediction of the fracture by applying respectively the Korean, Japanese, USA and UK model, and compared their FRAX results by calculating lumbar bone mineral density (BMD) instead of femoral neck BMD. RESULTS: The prediction of vertebral fracture using FRAX was 10.9 ± 6.2% in the fracture group, 9.5 ± 5.5% of the non-fracture group in the Korean model (p = 0.108); 17.9 ± 10.2% in the fracture group, 14.6 ± 9.0% in the non-fracture group in the Japanese model (p = 0.017). Only the Japanese model exhibited significant difference in vertebral fracture risk. The prediction of vertebral fracture using lumbar BMD instead of femoral neck BMD was 19.5 ± 12.1% in the fracture group, 16.0 ± 10.3% in the non-fracture group in the Korean model (p = 0.029). All models had statistically significant differences for the prediction of osteoporotic vertebral fracture. CONCLUSIONS: The 10-year probability of osteoporotic vertebral fracture had underestimation of the risk considering treatment eligibility based on the National Osteoporosis Foundation guidelines. BMD that accurately reflects the contribution of each result to fracture risk should be preferred for the prediction of fracture using FRAX, when lumbar spine and hip BMD measurements are both performed for clinical purposes in Korean.

Total hip arthroplasty using two-incision technique.

BACKGROUND: To evaluate the effectiveness of minimally invasive surgery total hip arthroplasty (THA) using the two-incision technique as described by Mears. METHODS: From January 2003 to December 2006, sixty-four patients underwent total hip arthroplasty using the one-incision (group I) and two-incision (group II) technique by one surgeon. There were 34 hips in group I and 30 hips in group II. There was no difference in age, gender, and causes of THA between the two groups. We evaluated the operation time, bleeding amount, incision length, ambulation, hospital stay, and complications between the two groups. RESULTS: There was no difference in the bleeding amount between the two groups. Operation time was longer in the two-incision group than in the one-incision group. Operation time of the two-incision technique could be reduced after 15 cases. Patients started ambulation after surgery earlier in group II than group I, and the hospital stay was shorter in group II than in group I. There was no difference in clinical results between the two groups. There was no difference in component position of the acetabular cup and femoral stem between the two groups. Intraoperative periprosthetic fracture occurred in four cases (13.3%) in group II. CONCLUSIONS: Two-incision THA has the advantage of rapid recovery and shorter hospital stay. However, longer operation time and a high complication rate compared to one-incision are problems that need to be solved in the two-incision technique.

Ligand-induced structural evolution of Pt55 nanoparticles: amine versus thiol.

We report the geometric and electronic effects of amine (with one lone pair electron) and thiol (with two lone pair electrons) ligands on the structural transformation of Pt(55) nanoparticles (NPs) by first-principles calculation. Although a cuboctahedral (COh) structure is less stable than an icosahedral (Ih) structure by 1.36 eV for a bare Pt(55) NP, the activation barrier from the COh to the Ih structure is very high, by 1.97 eV, indicating that it would be difficult to observe the structural evolution of a COh structure to an Ih structure for a bare Pt(55) NP at ambient temperature. However, with the help of the adsorption of methylamine, the structural evolution from a COh structure to an Ih structure is accomplished by the Mackay transformation. This transformation is driven by a combination of both the external forces resulting from the adsorption of the ligand, which pull out the Pt atoms on the face sites of NPs in a radial direction, and the contraction forces in a tangential direction. As more methylamine is added, the Ih structure is observed to return to the original COh structure owing to the directional orbital hybridization that occurs between the Pt NPs and the methylamine. In contrast, such structural evolutions are not observed in the case of methylthiol because the sulfur (S) in the ligand has two lone pair electrons, leading to two Pt-S bonds. As a result, the radial-directed external force that the NPs experience because of the adsorption of methylthiols is much lower than that found in methylamine-ligated NPs. Furthermore, the adsorption of methylthiol leads to an expansion (not contraction) in the tangential direction, which does not qualify as a Mackay transformation. Thus, the Pt NPs ligated with methylthiol do not have a driving force strong enough to cause structural change. The methylthiol-stabilized Pt NPs retain their initial COh structure despite an abundance of ligand adsorption. From these results, we suggest that the NP structure can be controlled by varying the amount and species of ligands.

Graphene veils and sandwiches.

We report a new and highly versatile approach to artificial layered materials synthesis which borrows concepts of molecular beam epitaxy, self-assembly, and graphite intercalation compounds. It readily yields stacks of graphene (or other two-dimensional sheets) separated by virtually any kind of "guest" species. The new material can be "sandwich like", for which the guest species are relatively closely spaced and form a near-continuous inner layer of the sandwich, or "veil like", where the guest species are widely separated, with each guest individually draped within a close-fitting, protective yet atomically thin graphene net or veil. The veils and sandwiches can be intermixed and used as a two-dimensional platform to control the movements and chemical interactions of guest species.

Squeaking sound in total hip arthroplasty using ceramic-on-ceramic bearing surfaces.

PURPOSE: To evaluate the causes and frequency of the squeaking sound in ceramic-on-ceramic THA. MATERIALS AND METHODS: This study included 61 hips of 50 patients who underwent ceramic-on-ceramic THA in our hospital from March 1999 to April 2005. The average age at the time of operation was 57.6 years. The average duration of follow-up was 69.5 months. Three different acetabular components were used: Osteonics (Stryker, USA: 24 cases), Bicontact (Aesculap, Germany: 27 cases) and ABG (Howmedica, UK: 10 cases). RESULTS: Fourteen (22.9%) of the 61 cases had a squeaking sound, and this sound started a mean of 47.57 months after the operation. Except in one case, the squeaking sound remained until the last follow-up. There was no difference in acetabular component position between the squeaking and nonsqueaking groups. The squeaking sound was found to be related to the BMI (body mass index) and cup design. It occurred frequently in patients with high BMI who had received a total hip arthroplasty using an Osteonics cup. Among 11 of the patients, squeaking occurred while squatting, and in 3 patients while walking. Six patients suffered from mild restrictions on their activities of daily living, and 8 had more than moderate restrictions with squeaking sounds. CONCLUSION: A squeaking sound in THA using ceramic-on-ceramic surfaces is not a rare complication, and often affects the patient's behavior.

Steering epitaxial alignment of Au, Pd, and AuPd nanowire arrays by atom flux change.

We have synthesized epitaxial Au, Pd, and AuPd nanowire arrays in vertical or horizontal alignment on a c-cut sapphire substrate. We show that the vertical and horizontal nanowire arrays grow from half-octahedral seeds by the correlations of the geometry and orientation of seed crystals with those of as-grown nanowires. The alignment of nanowires can be steered by changing the atom flux. At low atom deposition flux vertical nanowires grow, while at high atom flux horizontal nanowires grow. Similar vertical/horizontal epitaxial growth is also demonstrated on SrTiO(3) substrates. This orientation-steering mechanism is visualized by molecular dynamics simulations.

Phase diagram of Ag-Pd bimetallic nanoclusters by molecular dynamics simulations: solid-to-liquid transition and size-dependent behavior.

This report on the solid-to-liquid transition region of an Ag-Pd bimetallic nanocluster is based on a constant energy microcanonical ensemble molecular dynamics simulation combined with a collision method. By varying the size and composition of an Ag-Pd bimetallic cluster, we obtained a complete solid-solution type of binary phase diagram of the Ag-Pd system. Irrespective of the size and composition of the cluster, the melting temperature of Ag-Pd bimetallic clusters is lower than that of the bulk state and rises as the cluster size and the Pd composition increase. Additionally, the slope of the phase boundaries (even though not exactly linear) is lowered when the cluster size is reduced on account of the complex relations of the surface tension, the bulk melting temperature, and the heat of fusion. The melting of the cluster initially starts at the surface layer. The initiation and propagation of a five-fold icosahedron symmetry is related to the sequential melting of the cluster.

Segregation and internal structures in the bimetallic clusters: density functional theory and molecular dynamics simulation.

We study the coalescence between two nanoclusters composed of different transition metals. Using a molecular dynamics simulation at 500 K, we reveal the segregation along with the evolution of the number of atomic bonds. The density functional theory calculation is also used to investigate the distribution tendency of the solute atoms inside the host cluster in segregated systems. Internal structures which are predicted by the total binding energy and mixing enthalpy are well in accord with molecular dynamics simulation results.

Molecular dynamics simulations of the diffusion and rotation of Pt nanoclusters supported on graphite.

We study the diffusion and rotation of Pt nanoclusters supported on graphite. Using molecular dynamics simulation, we reveal that the supported Pt clusters have two types of bottom layers: a hexagonal lattice and a rectangular lattice. The diffusion rate of the Pt clusters mainly depends on the types of bottom layers. This observation is explained by the periodic lattice matching between the bottom layer and the graphite. In addition to lateral diffusion, we find that the Pt clusters with a rectangular or mixed lattice tend to rotate or wag on the z axis. By using the rotation rates and total movements of all atoms, we show that the rotation of a Pt cluster can be induced by the difference in the diffusion rates for the different types of bottom layers. This outcome is well in accord with our diffusion mechanism.