472 results on '"D. Ziegler"'
Search Results
2. Conjugate Acid–Base Interaction Driven Phase Transition at a 2D Air–Water Interface
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Lawrence D. Ziegler, Shyamsunder Erramilli, Ramprasath Rajagopal, Onuttom Narayan, and M. K. Hong
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Anions ,Phase transition ,Materials science ,ved/biology.organism_classification_rank.species ,010402 general chemistry ,01 natural sciences ,Phase Transition ,Ion ,Phase (matter) ,0103 physical sciences ,Materials Chemistry ,Physical and Theoretical Chemistry ,chemistry.chemical_classification ,010304 chemical physics ,ved/biology ,Air ,Water ,0104 chemical sciences ,Surfaces, Coatings and Films ,Lattice (module) ,chemistry ,Chemical physics ,Adsorption ,Lattice model (physics) ,Conjugate acid ,Organic acid ,Conjugate - Abstract
A lattice model is described to explain a recent striking Sum Frequency Generation (SFG) observation of a cooperative surface adsorption effect for an organic acid system at an air-water interface. The reported anomalous pH-dependent enhancement in p-methylbenzoic acid (pmBA) arises from an interaction between the acid (HA) and its conjugate base anion (A-), which competes with strong Coulombic repulsion between the conjugate bases (A--A -). Using a statistical mechanical approach, this lattice gas model reveals an analogy to well-studied magnetic systems in which the attraction between the two different molecular species leads to a phase transition to a two-dimensional checkerboard phase consisting of a network of anion-acid complexes formed at the low-dielectric air-water interface. Cooperative acid-anion interactions that control partitioning at solution and aerosol interfaces are of interest to fields ranging from oceanic and atmospheric chemistry, pharmacology, and chemical engineering.
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- 2021
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3. Chemical enhancement effects on protoporphyrin IX surface‐enhanced Raman spectra: Metal substrate dependence and a vibronic theory analysis
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James McNeely, Lawrence D. Ziegler, W. Ranjith Premasiri, and Harrison M. Ingraham
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Theory analysis ,chemistry.chemical_compound ,symbols.namesake ,Materials science ,Protoporphyrin IX ,chemistry ,symbols ,Metal substrate ,General Materials Science ,Raman spectroscopy ,Photochemistry ,Spectroscopy - Published
- 2020
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4. Estimating carbon biomass in forests using incomplete data
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Theodore A. Evans, Alan D. Ziegler, Tak Fung, Anuj Jain, and Lahiru S. Wijedasa
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chemistry ,Environmental science ,Biomass ,Climate change ,chemistry.chemical_element ,Forestry ,Carbon ,Ecology, Evolution, Behavior and Systematics ,Biomass carbon ,Tropical deforestation ,Basal area - Published
- 2020
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5. Dairy calf growth performance when fed a modified accelerated milk replacer program
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D. Schimek, Brittney M. Jaeger, D. Ziegler, David P. Casper, B. Ziegler, and Hugh Chester-Jones
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Starter ,Animal science ,Dairy heifer ,Chemistry ,Dairy calf ,Weaning ,Animal Science and Zoology ,Food Science - Abstract
Objective Our previous studies demonstrated that a modified accelerated milk replacer (MR) having a 24:20 CP:fat concentration fed at higher feeding rates (FR) resulted in improved growth performance and G:F, but the result was not linear. The objective of the current study was to evaluate preweaning (d 1 to 42) and postweaning (d 43 to 56) calf performance when a modified accelerated MR was fed at greater FR compared with a MR having similar or greater CP and lower fat concentrations. Materials and Methods A total of 126 (2 to 5 d old) Holstein heifer calves (40.1 ± 0.76 kg) were blocked by birthdate and randomly assigned to 1 of 5 treatments. Treatments of MR fed at 14.7% solids were (1) control (C−): all milk 24:20 MR fed at 0.26 kg at 2×/d from d 1 to 35; (2) C+: C− MR fed at 0.32 kg 2×/d from d 1 to 35; (3) LF: CP and low fat (24:16) MR fed at 0.32 kg 2×/d from d 1 to 35; (4) LF+: LF MR fed at 0.32 kg 2×/d from d 1 to 7 and at 0.39 kg from d 8 to 35; and (5) HP+: high CP:LF MR (26:16) using the same FR as LF+. All MR were fed 1×/d from d 36 to weaning at d 42 with water and 18% CP texturized calf starter offered free choice at all times. Results and Discussion Calves fed C+ had greater (P Implications and Applications This study demonstrates that feeding a modified accelerated MR (24:20) at a moderate FR improves ADG and frame measurements for calves fed MR having similar or different CP and fat concentrations. The development of a modified accelerated feeding program optimized the protein-to-energy ratio for producing a dairy heifer with a frame that is taller and wider, without having a postweaning BW gain slump.
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- 2020
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6. Anomalous pH-Dependent Enhancement of p-Methyl Benzoic Acid Sum-Frequency Intensities: Cooperative Surface Adsorption Effects
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Mi K. Hong, Lawrence D. Ziegler, Christina M. Miller, Xin Chen, Shane W. Devlin, Richard S. Andino, Ramprasath Rajagopal, Shyamsunder Erramilli, and Jian Liu
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010304 chemical physics ,Chemistry ,Ph dependent ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Adsorption ,0103 physical sciences ,Physical chemistry ,Carboxylate ,Physical and Theoretical Chemistry ,Spectroscopy ,Benzoic acid - Abstract
Vibrational sum-frequency generation (SFG) spectroscopy is used to determine the surface pKa of p-methyl benzoic acid (pMBA) at the air-water interface, by monitoring the carbonyl and carboxylate s...
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- 2020
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7. Growth performance of newborn dairy calves fed a milk replacer with 2 protein concentrations at 2 feeding rates
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Hugh Chester-Jones, David P. Casper, B. Ziegler, D. Schimek, Mary Raeth, Brittney M. Jaeger, and D. Ziegler
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Animal science ,Starter ,Chemistry ,High protein ,Animal Science and Zoology ,Feed conversion ratio ,Protein concentration ,Food Science - Abstract
Objective The objective was to evaluate the growth performance by calves fed a conventional milk replacer (MR) or modified accelerated MR (24% CP) to prevent the slump in postweaning calf starter intake and feed efficiency. Materials and Methods A total of 104 (1 to 5 d old) Holstein heifer calves (39.3 ± 0.66 kg) were assigned randomly to 1 of 4 MR treatments to evaluate preweaning (1 to 42 d) and postweaning (43 to 56 d) performance in a 2 × 2 factorial arrangement of CP concentrations [20% CP or 24% CP high protein (HP) with feeding rates (FR) of 0.57 or 0.68 kg/d]. Treatments were MR fed at 15% solids (as fed): (1) control (CP1): a 20% CP:20% fat MR fed at 0.284 kg 2×/d for 35 d; (2) CP2: the 20:20 MR fed at 0.34 kg 2×/d for 35 d; (3) HP1: a 24:20 MR fed at CP1 rate; and (4) HP2: the 24:20 MR fed at CP2 rate. Results and Discussion No interactions of CP by FR were detected for growth parameters. During 1 to 14 d, calves fed higher MR FR (CP2 and HP2) had greater (P 0.10). Intakes of calf starter from 1 to 56 d were similar (P > 0.10) for calves fed MR with different CP concentrations (0.77 and 0.78 kg/d), whereas calf starter intake (0.81 and 0.74 kg/d) was reduced (P 0.01) for calves fed different CP concentrations (0.54 and 0.55 kg/kg) but were improved when fed higher MR FR (0.53 and 0.56 kg/kg). However, a trend (P Implications and Applications Feeding calves a conventional MR (20%CP:20% fat) at different FR with different CP concentrations resulted in similar performance. Feeding a higher CP MR (24% CP:20% fat) at higher FR did not affect preweaning gain of dairy calves.
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- 2020
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8. Bucindolol Decreases Atrial Fibrillation Burden in Patients With Heart Failure and the ADRB1 Arg389Arg Genotype
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Jonathan P. Piccini, Christopher Dufton, Ian A. Carroll, Jeff S. Healey, William T. Abraham, Yaariv Khaykin, Ryan Aleong, Steven K. Krueger, William H. Sauer, Stephen B. Wilton, Michiel Rienstra, Dirk J. van Veldhuisen, Inder S. Anand, Michel White, A. John Camm, Paul D. Ziegler, Debra Marshall, Michael R. Bristow, Stuart J. Connolly, F Ayala-Paredes, A Bakbak, ML Bernier, DH Birnie, B Coutu, E Crystal, MW Deyell, KM Dyrda, MC Hartleib, ZW Laksman, P Leong-Sit, CA Morillo, AS Pandey, F Philippon, S Vizel, P Andréka, Z Csanadi, GZ Duray, T Forster, G Kerkovits, B Merkely, AC Nagy, T Simor, D Czarnecka, JD Kasprzak, WJ Musial, G Raczak, J Szachniewicz, JK Wranicz, S Apostolović, S Hinić, V Miloradović, D Simić, GJ Milhous, A Oomen, TJ Romer, LM van Vijk, PB Adamson, JD Allred, N Amjadi, MM Bahu, AJ Bank, AE Berman, MA Bernabei, RS Bhagwat, L Borgatta, AJ Buda, RT Cole, JL Collier, SJ Compton, O Costantini, MR Costanzo, IM Dauber, MP Donahue, I Dor, GF Egnacyzk, EJ Eichhorn, CC Eiswirth, S Emani, GA Ewald, RC Forde-McLean, MD Gelernt, DE Haines, CA Henrikson, JM Herre, B Herweg, L Ilkhanoff, LR Jackson, A Lala, R Lo, B London, BD Lowes, JA Mackall, V Malhotra, FA McGrew, S Murali, A Natale, KR Nilsson, J Okolo, MV Perez, RS Phang, R Ranjan, MY Rashtian, MJ Ross, SM Samii, T Shinn, MB Shoemaker, SA Strickberger, VN Tholakanahalli, A Tzur, PJ Wang, LT Younis, and Cardiovascular Centre (CVC)
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medicine.medical_specialty ,medicine.medical_treatment ,Population ,DRONEDARONE ,heart failure ,030204 cardiovascular system & hematology ,Cardioversion ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Physiology (medical) ,Internal medicine ,medicine ,Sinus rhythm ,atrial fibrillation ,030212 general & internal medicine ,education ,Metoprolol ,RISK ,education.field_of_study ,business.industry ,Bucindolol ,Atrial fibrillation ,medicine.disease ,metoprolol ,Dronedarone ,chemistry ,atrial flutter ,Cardiology ,TRIAL ,Cardiology and Cardiovascular Medicine ,business ,Atrial flutter ,bucindolol ,medicine.drug - Abstract
Background: Bucindolol is a genetically targeted β-blocker/mild vasodilator with the unique pharmacological properties of sympatholysis and ADRB1 Arg389 receptor inverse agonism. In the GENETIC-AF trial (Genotype-Directed Comparative Effectiveness Trial of Bucindolol and Toprol-XL for the Prevention of Symptomatic Atrial Fibrillation/Atrial Flutter in Patients With Heart Failure) conducted in a genetically defined heart failure population at high risk for recurrent atrial fibrillation (AF), similar results were observed for bucindolol and metoprolol succinate for the primary end point of time to first AF event; however, AF burden and other rhythm control measures were not analyzed. Methods: The prevalence of ECGs in normal sinus rhythm, AF interventions for rhythm control (cardioversion, ablation, and antiarrhythmic drugs) and biomarkers were evaluated in the overall population entering efficacy follow-up (N=257). AF burden was evaluated for 24 weeks in the device substudy (N=67). Results: In 257 patients with heart failure, the mean age was 65.6±10.0 years, 18% were female, mean left ventricular ejection fraction was 36%, and 51% had persistent AF. Cumulative 24-week AF burden was 24.4% (95% CI, 18.5–30.2) for bucindolol and 36.7% (95% CI, 30.0–43.5) for metoprolol (33% reduction, P P P P =0.011). Reductions in plasma norepinephrine ( P =0.038) and NT-proBNP (N-terminal pro B-type natriuretic peptide; P =0.009) were also observed with bucindolol compared with metoprolol. Conclusions: Compared with metoprolol, bucindolol reduced AF burden, improved maintenance of sinus rhythm, and lowered the need for additional rhythm control interventions in patients with heart failure and the ADRB1 Arg389Arg genotype. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01970501.
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- 2021
9. Glycidyltosylat: Die Polymerisation eines 'nicht polymerisierbaren' Monomers ermöglicht eine universelle, polymeranaloge Funktionalisierung von Polyethern
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Philipp Jung, Jan Blankenburg, Arthur D. Ziegler, and Holger Frey
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Chemistry ,General Medicine - Published
- 2019
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10. Glycidyl Tosylate: Polymerization of a 'Non‐Polymerizable' Monomer permits Universal Post‐Functionalization of Polyethers
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Arthur D. Ziegler, Jan Blankenburg, Philipp Jung, and Holger Frey
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Ethylene oxide ,ring-opening polymerization ,010405 organic chemistry ,Communication ,Leaving group ,Epoxide ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Ring-opening polymerization ,Communications ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Monomer ,chemistry ,Polymerization ,polyether ,Polymer chemistry ,Copolymer ,Nucleophilic substitution ,Ring‐Opening Polymerization ,functionalization ,poly(ethylene oxide) ,poly(propylene oxide) - Abstract
Glycidyl tosylate appears to be a non‐polymerizable epoxide when nucleophilic initiators are used because of the excellent leaving group properties of the tosylate. However, using the monomer‐activated mechanism, this unusual monomer can be copolymerized with ethylene oxide (EO) and propylene oxide (PO), respectively, yielding copolymers with 7–25 % incorporated tosylate‐moieties. The microstructure of the copolymers was investigated via in situ 1H NMR spectroscopy, and the reactivity ratios of the copolymerizations have been determined. Quantitative nucleophilic substitution of the tosylate‐moiety is demonstrated for several examples. This new structure provides access to a library of functionalized polyethers that cannot be synthesized by conventional oxyanionic polymerization.
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- 2019
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11. Bucindolol for the Maintenance of Sinus Rhythm in a Genotype-Defined HF Population
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Béla Merkely, William T. Abraham, Michael R. Bristow, Laura L. Emery, Dirk J. van Veldhuisen, Michel White, Ian A. Carroll, Michiel Rienstra, William H. Sauer, Ryan G. Aleong, Leonard Ilkhanoff, Paul D. Ziegler, Jeff S. Healey, Christopher Dufton, Jonathan P. Piccini, Gordon Davis, Inder S. Anand, Yaariv Khaykin, Debra Marshall, Stuart J. Connolly, David P. Kao, Jerzy Krzysztof Wranicz, Vladimir Miloradovic, Steven K. Krueger, Stephen B. Wilton, Genetic-Af Trial Investigators, and Felix Ayala-Paredes
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medicine.medical_specialty ,medicine.drug_class ,medicine.medical_treatment ,Population ,030204 cardiovascular system & hematology ,Cardioversion ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,medicine ,Sinus rhythm ,030212 general & internal medicine ,education ,Beta blocker ,Metoprolol ,education.field_of_study ,Ejection fraction ,business.industry ,Bucindolol ,Atrial fibrillation ,medicine.disease ,chemistry ,Cardiology ,Cardiology and Cardiovascular Medicine ,business ,medicine.drug - Abstract
Objectives The purpose of this study was to compare the effectiveness of bucindolol with that of metoprolol succinate for the maintenance of sinus rhythm in a genetically defined heart failure (HF) population with atrial fibrillation (AF). Background Bucindolol is a beta-blocker whose unique pharmacologic properties provide greater benefit in HF patients with reduced ejection fraction (HFrEF) who have the beta1-adrenergic receptor (ADRB1) Arg389Arg genotype. Methods A total of 267 HFrEF patients with a left ventricular ejection fraction (LVEF) Results The hazard ratio (HR) for the primary endpoint was 1.01 (95% confidence interval [CI]: 0.71 to 1.42), but trends for bucindolol benefit were observed in several subgroups. Precision therapeutic phenotyping revealed that a differential response to bucindolol was associated with the interval of time from the initial diagnoses of AF and HF to randomization and with the onset of AF relative to that of the initial HF diagnosis. In a cohort whose first AF and HF diagnoses were Conclusions Pharmacogenetically guided bucindolol therapy did not reduce the recurrence of AF/AFL or ACM compared to that of metoprolol therapy in HFrEF patients, but populations were identified who merited further investigation in future phase 3 trials.
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- 2019
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12. Plasmon-Enhanced Pan-Microbial Pathogen Inactivation in the Cavitation Regime: Selectivity Without Targeting
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Suryaram Gummuluru, Allyson E. Sgro, Björn M. Reinhard, Nhung Nguyen, Ayako Miura, Oliver McRae, Mark S. Aronson, Christopher Gillespie, Robert Smith, Lawrence D. Ziegler, Min Xi, Shyamsunder Erramilli, James Bird, Kathleen Souza, Edward Silva, Mi K. Hong, and Mina Nazari
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Microbial pathogenesis ,Antibiotic resistance ,Chemistry ,Cavitation ,Biophysics ,General Materials Science ,Current (fluid) ,Selectivity ,Antimicrobial ,Plasmon - Abstract
Pan-microbial inactivation technologies that do not require high temperatures, reactive chemical compounds, or UV radiation could address gaps in current infection control strategies and provide ef...
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- 2019
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13. Organic Substances in partly closed Water Cycles
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S. Wischnack, C. Hartig, D. Ziegler, and M. Jekel
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Chemistry ,Environmental chemistry ,Water cycle - Published
- 2020
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14. Carbon dynamics and inconstant porewater input in a mangrove tidal creek over contrasting seasons and tidal amplitudes
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Alan D. Ziegler, Daniel A. Friess, David Widory, Pierre Taillardat, Nguyen Thanh-Nho, Frank David, Vinh Truong Van, and Cyril Marchand
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0106 biological sciences ,chemistry.chemical_classification ,Hydrology ,010504 meteorology & atmospheric sciences ,010604 marine biology & hydrobiology ,Carbon sink ,chemistry.chemical_element ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Geochemistry and Petrology ,Carbon dioxide ,Dissolved organic carbon ,Environmental science ,Organic matter ,Mangrove ,Carbon ,Surface water ,Revelle factor ,0105 earth and related environmental sciences - Abstract
Constraining the contribution of mangrove-derived carbon in tidal creeks is fundamental to understanding the fate of mangrove primary production and the role of mangroves as coastal carbon sinks. Porewater measurements and 24-h time series in a mangrove tidal creek were conducted during the dry and wet season, and over contrasting tidal ranges at the Can Gio Biosphere Reserve, Vietnam. Surface water carbon concentrations (dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), partial pressure of carbon dioxide (pCO2)) and their respective δ13C values were correlated with radon, suggesting that porewater input drives mangrove-derived carbon in the tidal creek. Based on three complementary mixing models, porewater input contributed to about 30% of the water volume and 46% to 100% of DOC and DIC pools in the tidal creek at low tide, with variabilities between seasons and tidal amplitudes. The creek carbon pool was 88% DIC, 6% DOC, and 6% particulate organic carbon (POC). The pCO2 values during the wet season (2973–16,495 μatm) were on average 5-fold higher than during the dry season (584–2946 μatm). This was explained by a potential greater mineralization attributed to higher organic matter availability and residual humidity that stimulate bacterial activity, and by a potential tidal dilution changing the pCO2/DIC ratio as suggested by the Revelle factor. Consequently, average CO2 evasion from the creek was estimated at 327–427 mmolC m−2 d−1 during the wet season and 92–213 mmolC m−2 d−1 during the dry season, using two independent approaches. Tidal amplitude seemed to influence porewater input and its carbon loads, with a higher contribution during frequent and high tidal amplitudes (symmetric). However, the highest input occurred in a tidal cycle which was preceded by tidal cycle of low amplitude (asymmetric). We explain this ambiguity by the influence of both, rapid water turnover intensifying porewater exchange, and long water residence time enhancing carbon load in porewater.
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- 2018
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15. Surface enhanced Raman spectroscopy of Chlamydia trachomatis and Neisseria gonorrhoeae for diagnostics, and extra-cellular metabolomics and biochemical monitoring
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Ying Chen, Lawrence D. Ziegler, and W. R. Premasiri
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Guanine ,Silver ,Sexually Transmitted Diseases ,Metal Nanoparticles ,lcsh:Medicine ,Chlamydia trachomatis ,02 engineering and technology ,Nicotinamide adenine dinucleotide ,medicine.disease_cause ,Spectrum Analysis, Raman ,01 natural sciences ,Vibration ,Article ,Cell Line ,chemistry.chemical_compound ,Gonorrhea ,medicine ,Humans ,Metabolomics ,lcsh:Science ,Multidisciplinary ,biology ,Chemistry ,Adenine ,010401 analytical chemistry ,lcsh:R ,Surface-enhanced Raman spectroscopy ,Chlamydia Infections ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Neisseria gonorrhoeae ,0104 chemical sciences ,Biochemistry ,Metabolome ,lcsh:Q ,Neisseria ,Gold ,0210 nano-technology ,Bacterial outer membrane ,Bacteria - Abstract
SERS spectra excited at 785 nm of the bacteria Chlamydia trahomatis (elementary bodies, EB) and Neisseria gonorrheoae, the causative pathogens for the two most common sexually transmitted diseases (STD), chlamydia and gonorrhea, respectively, are reported. Although both are Gram-negative bacteria, the SERS signatures of C. trachomatis and N. gonorrheoae are completely different. N. gonorrheoae SERS spectra are due to the starvation induced nucleotide metabolites adenine and guanine, and the surface associated co-enzyme nicotinamide adenine dinucleotide and are very similar on Au and Ag although the spectrum appears more rapidly on Ag. The C. trachomatis SERS spectrum is dominated by the vibrational features of cell surface proteins. While features attributable to specific residues and the amide backbone characterize the C. trachomatis spectrum on Ag, the corresponding SERS spectrum on Au substrates displays vibrational characteristics of aggregated proteins. The prospects for the development of a SERS based platform for rapid (
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- 2018
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16. Surface enhanced Raman scattering specificity for detection and identification of dried bloodstains
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T. Reese, M. L. Shaine, C. Suarez, Lawrence D. Ziegler, Holly A. Ingraham, A. N. Brodeur, and W. R. Premasiri
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Chromatography ,Chemistry ,Metal Nanoparticles ,Forensic Medicine ,Surface-enhanced Raman spectroscopy ,Spectrum Analysis, Raman ,Fluorescence ,Peripheral blood ,Pathology and Forensic Medicine ,symbols.namesake ,Blood Stains ,symbols ,Animals ,Humans ,Gold ,Dried blood ,Raman spectroscopy ,Law ,Raman scattering - Abstract
Surface enhanced Raman spectroscopy (SERS) provides highly specific vibrational signatures identifying dried blood for a variety of forensic applications. SERS spectra on Au nanoparticle substrates excited at 785 nm are found to identify dried stains of human and nonhuman blood from seven animals, and distinguish stains due to menstrual and peripheral blood. In addition, the unique SERS bloodstain spectrum is distinct from the SERS spectra of thirty red-brown stains of potential household substances that could be visually mistaken for bloodstains and from food stains that have been shown to give positive results with presumptive colorimetric blood tests. Finally, a SERS swab procedure has been developed and demonstrates that the substrates that a blood sample dried on does not offer any Raman or fluorescence interference for the SERS identification of dried blood. Such bloodstains on porous and nonporous materials are all identical and exclusively due to the heme moiety of hemoglobin. Optimized selection of the extraction solvent is found to control the chemical composition of molecular components appearing in the SERS spectrum of complex, multicomponent biological mixtures, such as body fluids.
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- 2021
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17. Effects of feeding pasteurized waste milk to dairy calves on phenotypes and genotypes of antimicrobial resistance in fecal Escherichia coli isolates before and after weaning
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M. Terré, D. Ziegler, Alex Bach, G. Maynou, L. Migura-Garcia, and Hugh Chester-Jones
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0301 basic medicine ,Florfenicol ,Genotype ,030106 microbiology ,Weaning ,Biology ,medicine.disease_cause ,Feces ,03 medical and health sciences ,chemistry.chemical_compound ,fluids and secretions ,Antibiotic resistance ,Drug Resistance, Multiple, Bacterial ,Ampicillin ,Escherichia coli ,Genetics ,medicine ,Animals ,Food science ,Antimicrobial ,Anti-Bacterial Agents ,Milk ,Phenotype ,030104 developmental biology ,chemistry ,Pasteurization ,Cattle ,Female ,Animal Science and Zoology ,Ceftiofur ,Food Science ,medicine.drug - Abstract
The aim of this study was to evaluate the effects of feeding pasteurized waste milk (pWM) to calves on antimicrobial resistance of fecal Escherichia coli at both phenotypic and genotypic levels. Fifty-two Holstein female calves (3 ± 1.3 d of age) were fed 1 of the 2 different types of milk: milk replacer (MR) without antimicrobials or pWM with β-lactam residues until weaning at 49 d of age. Fecal swabs of all calves were obtained on d 0, 35, and 56 of the study and 3 E. coli isolates per sample were studied. Phenotypic resistance was tested by the disk diffusion method against a panel of 12 antimicrobials. A total of 13 resistance genes consisting of β-lactam, sulfonamide, tetracycline, and aminoglycoside families were examined by PCR. Feeding pWM to calves increased the presence of phenotypic resistance to ampicillin, cephalotin, ceftiofur, and florfenicol in fecal E. coli compared with MR-fed calves. However, the presence of resistance to sulfonamides, tetracyclines, and aminoglycosides was common in dairy calves independent of their milk-feeding source, suggesting other factors apart from the feeding source are involved in the emergence of antimicrobial resistance.
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- 2017
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18. Temporal Evolution of Low-Temperature Phonon Sidebands in Transition Metal Dichalcogenides
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Takashi Taniguchi, Malte Selig, Alexey Chernikov, Andreas Knorr, Jonas D. Ziegler, Raül Perea-Causín, Ermin Malic, Koloman Wagner, Samuel Brem, Edith Wietek, Roberto Rosati, Kenji Watanabe, and Jonas Zipfel
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Materials science ,Photoluminescence ,Condensed matter physics ,Phonon ,Exciton ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,3. Good health ,Electronic, Optical and Magnetic Materials ,010309 optics ,chemistry.chemical_compound ,chemistry ,Transition metal ,0103 physical sciences ,Monolayer ,Tungsten diselenide ,Electrical and Electronic Engineering ,0210 nano-technology ,Biotechnology - Abstract
Low-temperature photoluminescence (PL) of hBN-encapsulated monolayer tungsten diselenide (WSe2) shows a multitude of sharp emission peaks below the bright exciton. Some of them have been recently i...
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- 2020
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19. Intrinsic lifetime of higher excitonic states in tungsten diselenide monolayers
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Takashi Taniguchi, Ermin Malic, Archana Raja, Malte Selig, Kenji Watanabe, Alexey Chernikov, Lutz Waldecker, Jonas Zipfel, Samuel Brem, and Jonas D. Ziegler
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Technology ,Exciton ,FOS: Physical sciences ,02 engineering and technology ,Dielectric ,010402 general chemistry ,01 natural sciences ,Molecular physics ,Laser linewidth ,chemistry.chemical_compound ,Condensed Matter::Materials Science ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Monolayer ,cond-mat.mes-hall ,Tungsten diselenide ,General Materials Science ,Nanoscience & Nanotechnology ,Physics ,Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Scattering ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,cond-mat.mtrl-sci ,0104 chemical sciences ,chemistry ,Excited state ,Physical Sciences ,Chemical Sciences ,0210 nano-technology ,Ground state - Abstract
The reduced dielectric screening in atomically thin transition metal dichalcogenides allows to study the hydrogen-like series of higher exciton states in optical spectra even at room temperature. The width of excitonic peaks provides information about the radiative decay and phonon-assisted scattering channels limiting the lifetime of these quasi-particles. While linewidth studies so far have been limited to the exciton ground state, encapsulation with hBN has recently enabled quantitative measurements of the broadening of excited exciton resonances. Here, we present a joint experiment-theory study combining microscopic calculations with spectroscopic measurements on the intrinsic linewidth and lifetime of higher exciton states in hBN-encapsulated WSe$_2$ monolayers. Surprisingly, despite the increased number of scattering channels, we find both in theory and experiment that the linewidth of higher excitonic states is similar or even smaller compared to the ground state. Our microscopic calculations ascribe this behavior to a reduced exciton-phonon scattering efficiency for higher excitons due to spatially extended orbital functions.
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- 2019
20. Plasmon-enhanced Stimulated Raman Scattering Microscopy with Single-molecule Detection Sensitivity
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Yimin Huang, Cheng Zong, Ranjith Premasiri, Bin Ren, Lawrence D. Ziegler, Chi Zhang, Haonan Lin, Ji-Xin Cheng, and Chen Yang
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Chemical imaging ,Nonlinear Optical Microscopy ,General Physics and Astronomy ,02 engineering and technology ,Spectrum Analysis, Raman ,01 natural sciences ,Optical imaging ,law.invention ,law ,Microscopy ,lcsh:Science ,chemistry.chemical_classification ,Multidisciplinary ,021001 nanoscience & nanotechnology ,Single Molecule Imaging ,3. Good health ,Raman spectroscopy ,symbols ,Optoelectronics ,0210 nano-technology ,Raman scattering ,Physics - Optics ,Staphylococcus aureus ,Materials science ,Science ,FOS: Physical sciences ,Electrons ,010402 general chemistry ,General Biochemistry, Genetics and Molecular Biology ,Article ,symbols.namesake ,Stress, Physiological ,parasitic diseases ,Plasmon ,Nanophotonics and plasmonics ,Nitrogen Isotopes ,business.industry ,SERS ,Biomolecule ,Adenine ,Lasers ,technology, industry, and agriculture ,Reproducibility of Results ,General Chemistry ,Laser ,0104 chemical sciences ,chemistry ,lcsh:Q ,business ,Optics (physics.optics) - Abstract
Stimulated Raman scattering (SRS) microscopy allows for high-speed label-free chemical imaging of biomedical systems. The imaging sensitivity of SRS microscopy is limited to ~10 mM for endogenous biomolecules. Electronic pre-resonant SRS allows detection of sub-micromolar chromophores. However, label-free SRS detection of single biomolecules having extremely small Raman cross-sections (~10−30 cm2 sr−1) remains unreachable. Here, we demonstrate plasmon-enhanced stimulated Raman scattering (PESRS) microscopy with single-molecule detection sensitivity. Incorporating pico-Joule laser excitation, background subtraction, and a denoising algorithm, we obtain robust single-pixel SRS spectra exhibiting single-molecule events, verified by using two isotopologues of adenine and further confirmed by digital blinking and bleaching in the temporal domain. To demonstrate the capability of PESRS for biological applications, we utilize PESRS to map adenine released from bacteria due to starvation stress. PESRS microscopy holds the promise for ultrasensitive detection and rapid mapping of molecular events in chemical and biomedical systems., Stimulated Raman scattering (SRS) microscopy enables label-free chemical imaging at high speed, but has been limited by low sensitivity. Here, the authors demonstrate plasmon-enhanced SRS microscopy and achieve single molecule detection sensitivity.
- Published
- 2019
21. Pre-closure assessment of elevated arsenic and other potential environmental constraints to developing aquaculture and fisheries: The case of the Mae Moh mine and power plant, Lampang, Thailand
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K. Srinuansom, C.J. Chuah, Sorain J. Ramchunder, S.H.J. Woon, J. Promya, and Alan D. Ziegler
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Environmental Engineering ,Power station ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,Fisheries ,chemistry.chemical_element ,Aquaculture ,02 engineering and technology ,STREAMS ,010501 environmental sciences ,01 natural sciences ,Arsenic ,chemistry.chemical_compound ,Land reclamation ,Nitrate ,Environmental Chemistry ,0105 earth and related environmental sciences ,business.industry ,Public Health, Environmental and Occupational Health ,Coal mining ,General Medicine ,General Chemistry ,Thailand ,Pollution ,020801 environmental engineering ,Fishery ,chemistry ,Environmental science ,Water quality ,business ,Water Pollutants, Chemical ,Environmental Monitoring ,Power Plants - Abstract
Our assessment of 30 water bodies in the vicinity of the Mae Moh coal mine and power station in northern Thailand does not indicate substantial water quality management challenges to developing fisheries/aquaculture in peripheral reservoirs and streams. Negative water quality issues such as high concentrations of arsenic (2-17 μg/L) and ions including sulfate (868-2605 mg/L), sodium (217-552 mg/L), and total ammonia (1-5 mg/L) were associated with groundwater and surface water resources on the facility, as well as the stream network draining from it. Total dissolved solids were also very high, ranging from 658 to 3610 mg/L. Six of seven ponds tested had As concentrations in the range of 5-17 μg/L. Although these levels are less than the Thai regulation for industrial effluent, they are elevated over background surface water concentrations. The highest concentration in a contaminated stream was 10.54 μg/L As, which is only slightly above the WHO (2017) regulation of 10 μg/L for drinking water. Ponds, contaminated streams, and deep subsurface water should not be used for fisheries/aquaculture without extensive remediation/treatment. Concentrations of these water parameters in peripheral streams and reservoirs were not of environmental concern. High water hardness (161-397 mg/L CaCO
- Published
- 2021
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22. Structure Making and Breaking Effects of Cations in Aqueous Solution: Nitrous Oxide Pump–Probe Measurements
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Shyamsunder Erramilli, Jeffrey Shattuck, Parth P. Shah, and Lawrence D. Ziegler
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Aqueous solution ,Hydrogen ,Hydrogen bond ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Ion ,Solvation shell ,chemistry ,Materials Chemistry ,Density of states ,Vibrational energy relaxation ,Physical and Theoretical Chemistry ,0210 nano-technology ,Anisotropy - Abstract
Ultrafast IR pump-probe responses resonant with the ν3 asymmetric stretch of nitrous oxide (N2O) at ∼2230 cm-1 are reported for 2 M aqueous salt solutions of MgCl2, CaCl2, NaCl, KCl, and CsCl at room temperature. The solvated cations of these chloride solutions span the range from strongly to weakly hydrating ions, and correspondingly are often categorized as structure makers and structure breakers, respectively. The observed salt dependent trends of the N2O ν3 vibrational energy relaxation (VER) and rotational reorientation anisotropy (R(t)) decays are consistent with the categorization of these cations as structure breakers or makers, and show evidence of effects on the water hydrogen bonding network beyond the first solvation shell of these ions. This N2O mode is resonant with the H2O bend-libration band region. The corresponding FTIR is fitted well by a two Gaussian plus sloping continuum baseline model that allows a framework for characterizing the salt perturbations of the solvent spectral density in the ν3 resonant region. Both coupling strengths and density of states effects appear to contribute the systematic cation dependent T1 effects reported here. R(t) decays follow bulk viscosity values. These results are contrasted with previous IR pump-probe studies predominantly based on the relaxation dynamics of the OH/OD vibrational stretch of HOD hydrogen bonded to anions in salt solutions.
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- 2016
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23. Particulate carbon and nitrogen dynamics in a headwater catchment in Northern Thailand: hysteresis, high yields, and hot spots
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Chatchai Tantasirin, Melvin L. Kunkel, Alan D. Ziegler, Valerie X. H. Phang, Shawn G. Benner, and Massimo Lupascu
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Hydrology ,010504 meteorology & atmospheric sciences ,Headwater catchment ,chemistry.chemical_element ,010501 environmental sciences ,Particulates ,01 natural sciences ,Nitrogen ,chemistry ,Hysteresis (economics) ,Environmental science ,Turbidity ,Carbon ,Sediment transport ,0105 earth and related environmental sciences ,Water Science and Technology - Published
- 2016
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24. Fluoride: A naturally-occurring health hazard in drinking-water resources of Northern Thailand
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Alan D. Ziegler, Spencer H. Wood, Han Rui Lye, C. Joon Chuah, Chatpat Kongpun, and Sunsanee Rajchagool
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Environmental Engineering ,Fluorosis, Dental ,Water flow ,Water Wells ,0208 environmental biotechnology ,Aquifer ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Natural (archaeology) ,Fluorides ,chemistry.chemical_compound ,Health hazard ,Environmental Chemistry ,Groundwater ,Waste Management and Disposal ,Geothermal gradient ,0105 earth and related environmental sciences ,Hydrology ,geography ,geography.geographical_feature_category ,Drinking Water ,Environmental Exposure ,Thailand ,Pollution ,020801 environmental engineering ,Water resources ,chemistry ,Water Resources ,Fluoride ,Water Pollutants, Chemical ,Geology - Abstract
In Northern Thailand, incidences of fluorosis resulting from the consumption of high-fluoride drinking-water have been documented. In this study, we mapped the high-fluoride endemic areas and described the relevant transport processes of fluoride in enriched waters in the provinces of Chiang Mai and Lamphun. Over one thousand surface and sub-surface water samples including a total of 995 collected from shallow (depth: ≤ 30 m) and deep (> 30 m) wells were analysed from two unconnected high-fluoride endemic areas. At the Chiang Mai site, 31% of the shallow wells contained hazardous levels (≥ 1.5 mg/L) of fluoride, compared with the 18% observed in the deep wells. However, at the Lamphun site, more deep wells (35%) contained water with at least 1.5mg/L fluoride compared with the shallow wells (7%). At the Chiang Mai site, the high-fluoride waters originate from a nearby geothermal field. Fluoride-rich geothermal waters are distributed across the area following natural hydrological pathways of surface and sub-surface water flow. At the Lamphun site, a well-defined, curvilinear high-fluoride anomalous zone, resembling that of the nearby conspicuous Mae Tha Fault, was identified. This similarity provides evidence of the existence of an unmapped, blind fault as well as its likely association to a geogenic source (biotite-granite) of fluoride related to the faulted zone. Excessive abstraction of ground water resources may also have affected the distribution and concentration of fluoride at both sites. The distribution of these high-fluoride waters is influenced by a myriad of complex natural and anthropogenic processes which thus created a challenge for the management of water resources for safe consumption in affected areas. The notion of clean and safe drinking water can be found in deeper aquifers is not necessarily true. Groundwater at any depth should always be tested before the construction of wells.
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- 2016
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25. Land Use Effects on Mangrove Nutrient Status in Phang Nga Bay, Thailand
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Jan Willem Wolters, Lucy Gwen Gillis, M.M. van Katwijk, Alan D. Ziegler, and Tjeerd J. Bouma
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0106 biological sciences ,010504 meteorology & atmospheric sciences ,Land use ,Ecology ,010604 marine biology & hydrobiology ,Soil Science ,Land cover ,Development ,01 natural sciences ,Chemistry ,Nutrient ,Habitat ,Environmental Chemistry ,Environmental science ,Marine ecosystem ,Mangrove ,Eutrophication ,Biology ,Bay ,Environmental Sciences ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Tropical mangrove forests can play an important role in the functioning of adjacent marine ecosystems, by protecting them from an excess in land-derived sediment and nutrients. The strength of this interaction may however depend on the nutrient status of the mangrove forest. This study related the nutrient status of eight mangrove forests in Phang Nga Bay (Thailand) to the land-cover distributions in the upstream catchment areas. Nutrient status was assessed using indicators integrating over short (porewater and sediment nutrient composition) and long timespans (mangrove leaves and sesarmid crab tissue characteristics). Using multivariate statistics (PCA analysis), these nutrient status data were then related to the land cover data, which were obtained through the analysis of satellite imagery. Nutrient availability was lowest for mangroves in catchments with large natural vegetation cover and was elevated in catchments with increasing levels of anthropogenic influence. Furthermore, nutrient availability was significantly correlated with several forms of land use, including natural forest, rice paddies, cleared ground and urban areas. While all indicators supported these results, relationships were strongest for long-term indicators. Information on the relationship between land use in the catchment area and mangrove nutrient status may be important for the effective management of this habitat, as well as adjacent marine systems. Copyright © 2015 John Wiley & Sons, Ltd.
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- 2015
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26. P2EC.22 - Nanotechnology-Based Ozone Sensors Exploiting Low- Frequency Impedance Changes for Detection
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P. Savi, G. Naishadham, K. Naishadham, A. Marchisio, J.-M. Tulliani, D. Ziegler, and E. Bekyarova
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chemistry.chemical_compound ,Ozone ,chemistry ,law ,Environmental science ,Environmental pollution ,Nanotechnology ,Carbon nanotube ,Ozone exposure ,Low frequency ,Electrical impedance ,law.invention - Published
- 2018
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27. Spectroscopic evidence for the origin of odd-even effects in self-assembled monolayers and effects of substrate roughness
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Lawrence D. Ziegler, Ian D. Tevis, Jian Liu, Martin M. Thuo, Christina M. Miller, Jiahao Chen, Xin Chen, and Richard S. Andino
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chemistry.chemical_classification ,Sum-frequency generation ,General Physics and Astronomy ,Nanotechnology ,Self-assembled monolayer ,02 engineering and technology ,Substrate (electronics) ,Surface finish ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Spectral line ,0104 chemical sciences ,chemistry ,Chemical physics ,Monolayer ,Physical and Theoretical Chemistry ,0210 nano-technology ,Spectroscopy ,Alkyl - Abstract
This paper reports the effects of substrate roughness on the odd–even effect in n-alkanethiolate self-assembled monolayers (SAMs) probed by vibrational sum frequency generation (SFG) spectroscopy. By fabricating SAMs on surfaces across the so-called odd–even limit, we demonstrate that differentiation of the vibrational frequencies of CH3 from SAMs derived from alkyl thiols with either odd (SAMO) or even (SAME) numbers of carbons depends on the roughness of the substrate on which they are formed. Odd–even oscillation in SFG susceptibility amplitudes was observed for spectra derived from SAME and SAMO fabricated on flat surfaces (RMS roughness = 0.4 nm) but not on rougher surfaces (RMS roughness = 2.38 nm). In addition, we discovered that local chemical environments for the terminal CH3 group have a chain-length dependence. There seems to be a transition at around C13, beyond which SAMs become “solid-like”.
- Published
- 2017
28. Commuter exposure to black carbon, carbon monoxide, and noise in the mass transport khlong boats of Bangkok, Thailand
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Alan D. Ziegler, Erik Velasco, and Kelvin J.J. Ho
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Hydrology ,Pollutant ,chemistry.chemical_compound ,Noise ,Mass transport ,chemistry ,Environmental engineering ,Environmental science ,Transportation ,Carbon black ,General Environmental Science ,Civil and Structural Engineering ,Carbon monoxide - Abstract
This work quantifies commuter exposure to black carbon, CO and noise when waiting for and travelling in the mass transport khlong (canal) boats in Bangkok, Thailand. Exposure to toxic pollutants and acute noise is similar or worse than for other transportation modes. Mean black carbon concentrations observed at one busy pier and along the main canal were much higher than ambient concentrations at sites impacted by vehicular traffic. Concentrations of CO were similar to those reported for roadside areas of Bangkok. The equivalent continuous sound levels registered at the landing pier were similar to those reported for roadsides, but values recorded inside the boats were significantly higher.
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- 2013
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29. Driving forces of organic carbon spatial distribution in the tropical seascape
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Lucy Gwen Gillis, Alan D. Ziegler, F.E. Belshe, and Tjeerd J. Bouma
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0106 biological sciences ,Total organic carbon ,010504 meteorology & atmospheric sciences ,biology ,Ecology ,010604 marine biology & hydrobiology ,chemistry.chemical_element ,Vegetation ,Aquatic Science ,Carbon sequestration ,Oceanography ,biology.organism_classification ,01 natural sciences ,Blue carbon ,Seagrass ,chemistry ,Greenhouse gas ,Environmental science ,Ecosystem ,Carbon ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences - Abstract
An important ecosystem service of tropical coastal vegetation including seagrass beds and mangrove forests is their ability to accumulate carbon. Here we attempt to establish the driving forces for the accumulation of surface organic carbon in southern Thailand coastal systems. Across 12 sites we found that in line with expectations, seagrass beds (0.6 ± 0.09%) and mangrove forests (0.9 ± 0.3%) had higher organic carbon in the surface (top 5 cm) sediment than un-vegetated mudflats (0.4 ± 0.04%). Unexpectedly, however, mangrove forests in this region retained organic carbon, rather than outwell it, under normal tidal conditions. No relationship was found between organic carbon and substrate grain size. The most interesting finding of our study was that climax and pioneer seagrass species retained more carbon than mixed-species meadows, suggesting that plant morphology and meadow characteristics can be important factors in organic carbon accumulation. Insights such as these are important in developing carbon management strategies involving coastal ecosystems such as offsetting of carbon emissions. The ability of tropical coastal vegetation to sequester carbon is an important aspect for valuing the ecosystems. Our results provide some initial insight into the factors affecting carbon sequestration in these ecosystems, but also highlight the need for further research on a global scale.
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- 2017
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30. Rapid urinary tract infection diagnostics by surface-enhanced Raman spectroscopy (SERS): identification and antibiotic susceptibilities
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C Pyles, W. R. Premasiri, Ying Chen, Patrick M. Williamson, Lawrence D. Ziegler, and D C Bandarage
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Guanine ,02 engineering and technology ,Urine ,Spectrum Analysis, Raman ,01 natural sciences ,Biochemistry ,Sensitivity and Specificity ,Analytical Chemistry ,chemistry.chemical_compound ,Humans ,Centrifugation ,Sample preparation ,Hypoxanthine ,010401 analytical chemistry ,Reproducibility of Results ,Bacterial Infections ,Surface-enhanced Raman spectroscopy ,021001 nanoscience & nanotechnology ,Xanthine ,0104 chemical sciences ,Anti-Bacterial Agents ,Bacterial Typing Techniques ,chemistry ,Urinary Tract Infections ,Uric acid ,0210 nano-technology - Abstract
SERS spectra of 12 bacterial strains of urinary tract infection (UTI) clinical isolates grown and enriched from urine are reported. A partial least squares-discriminant analysis (PLS-DA) classification treatment of these SERS spectra results in strain level identification with >95% sensitivity and >99% specificity. The classification model successfully identified the SERS spectra of a urine-cultured strain not used to build this statistical model. Enrichment was accomplished by a filtration and centrifugation protocol. The predetermined drug susceptibility profiles of these clinical isolates thus allowed the SERS methodology to provide appropriate UTI antibiotic information in less than 1 h. Most of this time was used for sample preparation procedures (enrichment and washing) for this proof of principle study. SERS spectra of the enriched bacterial samples are dominated by nucleotide degradation metabolites: adenine, hypoxanthine, xanthine, guanine, uric acid, AMP, and guanosine. Strain-specific specificity is due to the different relative amounts of these purines contributing to the corresponding SERS spectra of these clinical isolates. All measurements were made at the minimal bacterial concentration in urine for UTI diagnosis (105 cfu/mL).
- Published
- 2017
31. Effects of cinnamaldehyde or monensin on performance of weaned Holstein dairy heifers
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J.A. Clapper, C. E. Chapman, Peter S. Erickson, D. Ziegler, and Hugh Chester-Jones
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0301 basic medicine ,animal structures ,animal diseases ,Weaning ,Biology ,Cinnamaldehyde ,Blood Urea Nitrogen ,03 medical and health sciences ,chemistry.chemical_compound ,Animal science ,Every other week ,Ground corn ,Genetics ,Animals ,Acrolein ,Monensin ,Feces ,Completely randomized design ,Body Weight ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Animal Feed ,Diet ,030104 developmental biology ,chemistry ,Hay ,Animal Science and Zoology ,Cattle ,Female ,Barn (unit) ,Food Science - Abstract
The objective of this 70-d study was to determine the effects of the essential oil cinnamaldehyde compared with the ionophore monensin on performance of weaned Holstein dairy heifers. Eighty-four Holstein dairy heifers (91 ± 3.33 d of age; 109 ± 7.55 kg) were housed in a naturally ventilated curtain sidewall, straw-bedded barn in 12 pens with 7 heifers/pen (3.98 m2/head). Heifers were randomly assigned to 1 of 4 treatments in a completely randomized design: (1) control (CON; carrier, 908 g of ground corn), (2) monensin sodium [MON; 1 mg/kg of body weight (BW) + carrier], (3) cinnamaldehyde (CIN1; 1 mg/kg of BW + carrier), or (4) cinnamaldehyde (CIN2; 2 mg/kg of BW + carrier). The treatments were hand-mixed into a 20% crude protein (CP) whole shelled corn and protein pellet mix fed at 2.21 kg/heifer daily. Heifers had access to free-choice hay and water daily. Initial BW and hip heights were taken at the start of the study and every other week thereafter until calves reached 23 wk of age. Blood samples were also taken on each weigh day to determine plasma urea nitrogen, glucose, and insulin-like growth factor-1 concentrations. Fecal samples were taken from the same 3 heifers/pen initially and then at d 28, 56, and 70 of the study for coccidia counts. Cinnamaldehyde had no performance effects on growth, hay intake, hip height, or blood metabolites compared with MON or CON. Average daily gains were 0.98, 0.99, 1.01, and 1.03 kg/d, and average hay intakes per pen were 17.08, 16.34, 18.11, and 17.60 kg/d for CON, MON, CIN1, and CIN2, respectively. Fecal samples by pens indicated the presence of viable coccidia, but the counts were low and not consistent across heifers within each pen. No benefits were associated with supplementing cinnamaldehyde or monensin into grain mixes for weaned heifers.
- Published
- 2016
32. Rapid Detection of Bacteria from Blood with Surface-Enhanced Raman Spectroscopy
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Lawrence D. Ziegler, Milos Miljkovic, W. Ranjith Premasiri, Catherine M. Klapperich, Jean C. Lee, Anna K. Boardman, Andre Sharon, Alexis F. Sauer-Budge, and Winnie S. Wong
- Subjects
Staphylococcus aureus ,Surface Properties ,Microorganism ,Analytical chemistry ,02 engineering and technology ,Spectrum Analysis, Raman ,01 natural sciences ,Rapid detection ,Article ,Analytical Chemistry ,medicine ,Escherichia coli ,Humans ,Model set ,Sample preparation ,Blood culture ,Whole blood ,Chromatography ,biology ,medicine.diagnostic_test ,Chemistry ,010401 analytical chemistry ,Surface-enhanced Raman spectroscopy ,021001 nanoscience & nanotechnology ,biology.organism_classification ,0104 chemical sciences ,0210 nano-technology ,Bacteria - Abstract
Traditional methods for identifying pathogens in bacteremic patients are slow (24–48+ h). This can lead to physicians making treatment decisions based on an incomplete diagnosis and potentially increasing the patient’s mortality risk. To decrease time to diagnosis, we have developed a novel technology that can recover viable bacteria directly from whole blood and identify them in less than 7 h. Our technology combines a sample preparation process with surface-enhanced Raman spectroscopy (SERS). The sample preparation process enriches viable microorganisms from 10 mL of whole blood into a 200 μL aliquot. After a short incubation period, SERS is used to identify the microorganisms. We further demonstrated that SERS can be used as a broad detection method, as it identified a model set of 17 clinical blood culture isolates and microbial reference strains with 100% identification agreement. By applying the integrated technology of sample preparation and SERS to spiked whole blood samples, we were able to correctly identify both Staphylococcus aureus and Escherichia coli 97% of the time with 97% specificity and 88% sensitivity.
- Published
- 2016
33. The biochemical origins of the surface enhanced Raman spectra of bacteria: metabolomics profiling by SERS
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Alexis F. Sauer-Budge, Jean C. Lee, Catherine E. Costello, Lawrence D. Ziegler, Roger Théberge, and W. Ranjith Premasiri
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Purine ,Spectrometry, Mass, Electrospray Ionization ,Guanine ,Surface Properties ,02 engineering and technology ,Spectrum Analysis, Raman ,01 natural sciences ,Biochemistry ,Article ,Analytical Chemistry ,Isotopic labeling ,chemistry.chemical_compound ,Metabolomics ,Purine metabolism ,Hypoxanthine ,Bacteria ,010401 analytical chemistry ,Surface-enhanced Raman spectroscopy ,021001 nanoscience & nanotechnology ,Xanthine ,0104 chemical sciences ,chemistry ,Isotope Labeling ,0210 nano-technology - Abstract
The dominant molecular species contributing to the surface-enhanced Raman spectroscopy (SERS) spectra of bacteria excited at 785 nm are the metabolites of purine degradation: adenine, hypoxanthine, xanthine, guanine, uric acid, and adenosine monophosphate. These molecules result from the starvation response of the bacterial cells in pure water washes following enrichment from nutrient-rich environments. Vibrational shifts due to isotopic labeling, bacterial SERS spectral fitting, SERS and mass spectrometry analysis of bacterial supernatant, SERS spectra of defined bacterial mutants, and the enzymatic substrate dependence of SERS spectra are used to identify these molecular components. The absence or presence of different degradation/salvage enzymes in the known purine metabolism pathways of these organisms plays a central role in determining the bacterial specificity of these purine-base SERS signatures. These results provide the biochemical basis for the development of SERS as a rapid bacterial diagnostic and illustrate how SERS can be applied more generally for metabolic profiling as a probe of cellular activity. Graphical Abstract Bacterial typing by metabolites released under stress.
- Published
- 2016
34. Organic carbon fluxes from the upper Yangtze basin: an example of the Longchuanjiang River, China
- Author
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Alan D. Ziegler, Min He, Yue Zhou, Li Li, Siyue Li, and Xixi Lu
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Hydrology ,chemistry.chemical_classification ,Total organic carbon ,geography ,geography.geographical_feature_category ,Drainage basin ,chemistry.chemical_element ,Sediment ,Carbon cycle ,Total inorganic carbon ,chemistry ,Dissolved organic carbon ,Environmental science ,Organic matter ,Carbon ,Water Science and Technology - Abstract
To investigate the effects of anthropogenic activity, namely, land use change and reservoir construction, on particulate organic carbon (POC) transport, we collected monthly water samples during September 2007 to August 2009 from the Longchuanjiang River to understand seasonal variations in the concentrations of organic carbon species and their sources and the yield of organic and inorganic carbon from the catchment in the Upper Yangtze basin. The contents of riverine POC, total organic carbon and total suspended sediment (TSS) changed synchronously with water discharge, whereas the contents of dissolved organic carbon had a small variation. The POC concentration in the suspended sediment decreased non-linearly with increasing TSS concentration. Higher molar C/N ratio of particulate organic matter (average 77) revealed that POC was dominated by terrestrially derived organic matter in the high flows and urban wastewaters in the low flows. The TSS transported by this river was 2.7 × 105 t/yr in 2008. The specific fluxes of total organic carbon and dissolved inorganic carbon (DIC) were 5.6 and 6 t/km2/yr, respectively, with more than 90% in the high flow period. A high carbon yield in the catchment of the upper Yangtze was due to human-induced land use alterations and urban wastes. Consistent with most rivers in the monsoon climate regions, the dissolved organic carbon–POC ratio of the export flux was low (0.41). Twenty-two percent (0.9 t/km2/yr) of POC out of 4 t/km2/yr was from autochthonous production and 78% (3.1 t/km2/yr) from allochthonous production. The annual sediment load and hence the organic carbon flux have been affected by environmental alterations of physical, chemical and hydrological conditions in the past 50 years, demonstrating the impacts of human disturbances on the global and local carbon cycling. Finally, we addressed that organic carbon flux should be reassessed using adequate samples (i.e. at least two times in low-flow month, four times in high-flow month and one time per day during the flood period), daily water discharge and sediment loads and appropriate estimate method. Copyright © 2011 John Wiley & Sons, Ltd.
- Published
- 2011
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35. Seasonal changes of nutrient fluxes in the Upper Changjiang basin: An example of the Longchuanjiang River, China
- Author
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Xixi Lu, Min He, Yue Zhou, Rongta Bei, Alan D. Ziegler, Siyue Li, and Li Li
- Subjects
Hydrology ,geography ,geography.geographical_feature_category ,Phosphorus ,chemistry.chemical_element ,Particulates ,Seasonality ,medicine.disease ,Algal bloom ,Nutrient ,chemistry ,Soil water ,Tributary ,Erosion ,medicine ,Environmental science ,Water Science and Technology - Abstract
summary Fluxes of dissolved and particulate nitrogen (N) and phosphorus (P) variables were measured monthly from September 2007 to March 2009 in the upper Longchuanjiang River (Yunnan Province, China) to determine annual loads and seasonal variability. Dissolved N (DN) and particle associated P (PAP) contributed 56% and 99% of the total nitrogen (TN) and total phosphorus (TP) yields of 549 and 608 kg/km 2 /yr. Fluxes of particulate N (PN), dissolved P (DP), PAP and TP exhibited great seasonality because they were highly correlated with water discharge. Areal export rates of NH þ 4 –N, PN, PAP and TP were higher than in the main channel and most tributaries of the Changjiang River. High particulate loads were contributed to erosion of phosphorus-rich soils during heavily rains in the wet season. Median measured concentrations of TN, NH þ 4 –N and TP exceeded the maximum permissible limit for domestic and recreational use in China. High nitrogen and phosphorus concentrations draw attention to the potential for additional nutrient loading to foster the formation of algal blooms in locations where free-flowing river sections are changing into cascades of reservoirs. Importantly, the great seasonality in the data shows necessity of sufficient sampling for determining annual fluxes.
- Published
- 2011
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36. Major element chemistry in the upper Yangtze River: A case study of the Longchuanjiang River
- Author
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Xixi Lu, Siyue Li, Yue Zhou, Alan D. Ziegler, Rongta Bei, Li Li, and Min He
- Subjects
Hydrology ,Cationic exchange ,Chine ,chemistry.chemical_compound ,chemistry ,Discharge ,Yangtze river ,Carbonate ,Monsoon ,Far East ,Geology ,Earth-Surface Processes - Abstract
article Water samples were collected twice per month over a two-year period from the Longchuanjiang River (Yunnan Province, China) to understand monthly variations in major elements and solute fluxes as related to rock weatheringand associatedCO2consumption rates. Solute concentrations were 5 times the medianof 65 mg/l for global average. Total cationic exchange capacity (Tz +
- Published
- 2011
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37. On the Difference Between Surface-Enhanced Raman Scattering (SERS) Spectra of Cell Growth Media and Whole Bacterial Cells
- Author
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Lawrence D. Ziegler, Yoseph Gebregziabher, and W. Ranjith Premasiri
- Subjects
Chemistry ,Cell growth ,Analytical chemistry ,Surface-enhanced Raman spectroscopy ,Spectral line ,symbols.namesake ,symbols ,Nitrogen source ,Raman spectroscopy ,Instrumentation ,Water washing ,Spectroscopy ,Raman scattering ,Vibrational spectra - Abstract
It has been recently suggested [N. E. Marotta and L. A. Bottomley, Appl. Spectrosc. 64, 601-606 (2010)] that previously reported surface-enhanced Raman scattering (SERS) spectra of vegetative bacterial cells are due to residual cell growth media that were not properly removed from samples of the lab-cultured microorganism suspensions. SERS spectra of several commonly used cell growth media are similar to those of bacterial cells, as shown here and reported elsewhere. However, a multivariate data analysis approach shows that SERS spectra of different bacterial species grown in the same growth media exhibit different characteristic vibrational spectra, SERS spectra of the same organism grown in different media display the same SERS spectrum, and SERS spectra of growth media do not cluster near the SERS spectra of washed bacteria. Furthermore, a bacterial SERS spectrum grown in a minimal medium, which uses inorganics for a nitrogen source and displays virtually no SERS features, exhibits a characteristic bacterial SERS spectrum. We use multivariate analysis to show how successive water washing and centrifugation cycles remove cell growth media and result in a robust bacterial SERS spectrum in contrast to the previous study attributing bacterial SERS signals to growth media.
- Published
- 2011
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38. Understanding the history of extreme wave events in the TuamotuArchipelago of French Polynesia from large carbonate boulders on Makemo Atoll, with implications for future threats in the central South Pacific
- Author
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Samuel Etienne, Alan D. Ziegler, Adam D. Switzer, James P. Terry, A. Y. Annie Lau, Yingsin Lee, Department of Geography, National University of Singapore, College of Sustainability Sciences and Humanities, Zayed University, Division of Earth Sciences [Singapore], Nanyang Technological University [Singapour], Earth Observatory of Singapore (EOS), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris-Sorbonne (UP4)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,Coral ,Atoll ,atoll ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,010502 geochemistry & geophysics ,Oceanography ,01 natural sciences ,chemistry.chemical_compound ,Geochemistry and Petrology ,cycclone tropical ,vague ,14. Life underwater ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,Reef ,ComputingMilieux_MISCELLANEOUS ,[SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,Landform ,Geology ,rocher ,chemistry ,[SDU]Sciences of the Universe [physics] ,Archipelago ,Pacifique Sud ,Carbonate ,Cyclone ,tsunami ,Tropical cyclone - Abstract
Numerous large carbonate boulders up to 164 tonnes in mass were investigated on the reef flat and beaches of Makemo Atoll in the Tuamotu Archipelago of French Polynesia to reveal the past occurrence and to anticipate the future potential threat of extreme wave events, possibly generated by tropical cyclones and tsunamis. The modern reef edge and emerged mid-Holocene coastal landforms were identified as sources of boulders mobilized during extreme wave events in the past. The minimum flow velocities produced by extreme wave events were estimated to exceed 5.4–15.7 m/s at the reef edge on different parts of the atoll. Comparison of uranium–thorium ages of boulder coral fabric with written historical records indicates that two large boulders (77 and 68 tonnes) were possibly emplaced on the reef flat by a powerful cyclone in February 1878. Although most boulder dates are older than the earliest historical cyclone and tsunami records in French Polynesia, their ages concur with the following: (a) periods of “storminess” (i.e. increased cyclone activity compared to today) in the central South Pacific over the last millennium; and (b) periods of high sea-surface temperature (SST) at the Great Barrier Reef, possibly associated with higher-than-normal SSTs Pacific-wide that facilitated the generation of cyclones affecting the central South Pacific Ocean. None of the boulders on Makemo were dated younger than CE1900, implying that the last century has not experienced extreme waves of similar magnitude in the past. Nevertheless, the findings suggest that waves of comparable magnitudes to those that have transported large boulders on Makemo may recur in the Tuamotus and threaten island coasts across the central South Pacific in the future.
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- 2016
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39. Ultrafast vibrational relaxation of liquid H2O following librational combination band excitation
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Jason J. Amsden, Logan R. Chieffo, Shyamsunder Erramilli, Lawrence D. Ziegler, and Jeffrey Shattuck
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Chemistry ,Excited state ,Intermolecular force ,Libration ,Vibrational energy relaxation ,General Physics and Astronomy ,Physical and Theoretical Chemistry ,Atomic physics ,Low frequency ,Ground state ,Ultrashort pulse ,Excitation - Abstract
Dispersed pump–probe responses excited by ∼165 fs pulses resonant with the bend–libration combination band in neat H 2 O centered at 2130 cm −1 are reported. This is the first IR pump–probe study of the energy relaxation dynamics in this region of the liquid water spectrum. The observed transient responses are best described by a kinetic model where the initial combination band energy relaxes via a concerted process to a bend fundamental and low frequency modes. The bend subsequently decays to another intermediate vibrational level, presumably the librational band, before this energy is distributed to low frequency modes and appears as heat as well in the sample volume in accordance with the results of Lindner et al. [L. Lindner, P. Vohringer, M.S. Pshenichnikov, D. Cringus, D.A. Wiersma, M. Mostovoy, Chem. Phys. Lett. 421 (2006) 329]. The lifetime of the bend–libration combination band is determined to be 140 ± 15 fs and the lifetime of the libration levels, leading to the hot ground state from the delayed heating route, is 840 ± 100 fs. This libration decay rate is consistent with the results of previous IR pump–probe measurement analyses for the appearance of heat following excitation resonant with the bend or stretch fundamentals. An additional pulse width limited absorption component is seen in all responses which may be attributed to the underlying continuum of intermolecular states in this region of the H 2 O spectrum.
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- 2007
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40. Urinary 8-epi-PGF2α and its endogenous β-oxidation products (2,3-dinor and 2,3-dinor-5,6-dihydro) as biomarkers of total body oxidative stress
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M.B. Cooper, D.J. Betteridge, Jaffar Nourooz-Zadeh, and D. Ziegler
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Adult ,Male ,Biophysics ,Ethyl acetate ,Dinoprost ,medicine.disease_cause ,Biochemistry ,High-performance liquid chromatography ,Gas Chromatography-Mass Spectrometry ,Lipid peroxidation ,Excretion ,chemistry.chemical_compound ,medicine ,Humans ,Sample preparation ,Molecular Biology ,F2-Isoprostanes ,Creatinine ,Chromatography ,Molecular Structure ,Chemistry ,Cell Biology ,Isoprostanes ,Oxidative Stress ,Female ,Oxidation-Reduction ,Biomarkers ,Oxidative stress - Abstract
Although measurements of plasma F2-isoprostanes are established markers of oxidative stress, their quantification only reflects acute non-enzymatic lipid peroxidation. In this study, a new approach is described for the rapid isolation and measurement of urinary 8-epi-PGF2alpha and its endogenous beta-oxidation metabolites (2,3-dinor-8-epi-PGF2alpha and 2,3-dinor-5,6-dihydro-PGF2alpha) for use as index of total body oxidative stress. Isoprostanes were partitioned with ethyl acetate and subsequently purified by chromatography on an aminopropyl (NH2) and silica (Si) cartridge. Final analysis of F2-isoprostanes as trimethylsilyl-ester/pentafluorobenzyl ester derivatives was carried out by stable isotope dilution mass spectrometry. Overall recovery of F2-isoprostanes was 80+/-4%. Inter- and intra-assay coefficients of variation were 5% and 7%, respectively. In a group of healthy humans, the mean excretion rates expressed as nmol/mmol creatinine for 2,3-dinor-8-epi-PGF2alpha, 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha, and 8-epi-PGF2alpha were 5.43+/-1.93, 2.16+/-0.71, and 0.36+/-0.16, respectively. Correlations were obtained between 8-epi-PGF2alpha and 2,3-dinor-8-epi-PGF2alpha or 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha (r=0.998 and r=0.937, respectively). A strong relationship was also seen between 2,3-dinor-8-epi-PGF2 and 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha (r=0.949). The new technique allows for high sample throughput and avoids the need for HPLC and/or other expensive equipment required for the initial sample preparation. Simultaneous analysis of urinary 8-epi-PGF2alpha and its metabolites should provide unique tool in clinical trials exploring the role of oxidant injury in human disease.
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- 2005
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41. Metal extraction from road-deposited sediments using nine partial decomposition procedures
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Alan D. Ziegler, Filip Tack, Joseph O. Bussen, and Ross A. Sutherland
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Extraction (chemistry) ,Contamination ,Pollution ,Decomposition ,Metal ,Matrix (chemical analysis) ,chemistry.chemical_compound ,Acetic acid ,chemistry ,Geochemistry and Petrology ,Reagent ,visual_art ,visual_art.visual_art_medium ,Environmental Chemistry ,Aqua regia ,Organic chemistry ,Nuclear chemistry - Abstract
Nine partial decomposition procedures and a total digestion treatment were applied to road-deposited sediments. The objective was to define a parsimonious, time-efficient decomposition procedure that (1) has limited impact on the alumnio-silicate matrix and/or refractory-associated fractions, (2) has metal recoveries independent of CaCO 3 content, and (3) produces high anthropogenic signals for known contaminants (e.g., Cu, Pb and Zn). The 9 digestions varied from weak single reagents (0.11 M acetic acid) to strong multi-step procedures (BCR 3-step plus aqua regia). Eight metals were examined: Al, Co, Cu, Fe, Mn, Ni, Pb, and Zn. Cold (room temperature) 0.5 M HCl shaken over a 1-h period with a solid-to-solution ratio of 1 g:20 ml, was judged superior based on the defined criteria. This simple, rapid treatment had limited impact on the residual matrix (mean and 95% confidence interval for Al recovery was 6±1%); recoveries of all elements examined were independent of CaCO 3 content; the treatment produced high mean extraction efficiencies for Cu (58±9%), Pb (84±5%), and Zn (73±7%), and produced high anthropogenic signals. Thus, dilute HCl can be widely recommended as an optimal partial decomposition procedure for assessing non-residual fractions of complex solid media.
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- 2004
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42. Ultrafast Two-Photon Absorption Approach to Optical Line Shape Measurements
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Lawrence D. Ziegler
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Chemistry ,business.industry ,Physics::Optics ,Molecular physics ,Two-photon absorption ,Spectral line ,symbols.namesake ,Wavelength ,Fourier transform ,Optics ,Absorption band ,symbols ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) ,Raman spectroscopy ,business ,Excitation - Abstract
An analysis of optical heterodyne detected (OHD) two-photon absorption (TPA) resonant signals in transparent materials is presented. The formal analogies between the vibrationally resonant Raman and electronically resonant TPA P ( 3 ) signals and response functions are given. Fourier transform procedures are shown to allow recovery of the complex TPA response function and eliminate residual Raman contributions from these spatially selected OHD TPA responses. The phase selectivity and wavelength dependence of this technique can be exploited to reveal both the real and imaginary parts of the line shape function describing the solute-solvent response to the two-photon resonant electronic excitation. In-phase and in-quadruture measurements at any resonant wavelength yield the absorption band shape. Intramolecular vibronic structure can be determined for totally diffuse absorption bands. These effects are illustrated by the analysis of two model electronic absorption systems: the MD-simulated methyl iodide B-state origin band in Ar and a multimode Brownian-oscillator-modeled absorption line shape with simple vibronic structure. Electronic excitations less accessible to one-photon resonant ultrafast studies such as UV/VUV transition, electronic excitations in inherently optically dense media, and dipole-forbidden states are well suited for study by this TPA approach.
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- 2003
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43. Particulate Matter in Mangrove Forests and Seagrass Beds as a Nitrogen Source in Tropical Coastal Ecosystems
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Alan D. Ziegler, Peter M. J. Herman, Tjeerd J. Bouma, Cecile Cathalot, and Lucy Gwen Gillis
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0106 biological sciences ,010504 meteorology & atmospheric sciences ,chemistry.chemical_element ,01 natural sciences ,nitrogen ,Nutrient ,Ecosystem ,14. Life underwater ,Nitrogen source ,Ecology, Evolution, Behavior and Systematics ,0105 earth and related environmental sciences ,mangrove forests ,biology ,Ecology ,010604 marine biology & hydrobiology ,buffering ,outwelling ,seagrass beds ,15. Life on land ,Particulates ,biology.organism_classification ,Nitrogen ,Seagrass ,chemistry ,Outwelling ,Environmental science ,Mangrove ,particulate organic material - Abstract
We show in laboratory and field investigations that in the short-term seagrasses obtain most of their required nitrogen from the degradation of seagrass leaves, rather than degradation of leaves exported from adjacent mangroves. Mangrove forests at our Thailand site retain the majority of their nutrients, and therefore potentially buffer seagrasses from nutrients.
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- 2015
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44. Polarization Specific Ultrafast Nuclear Dichroic Responses: Raman Spectral Density Recovery and Coherent Coupling Effects
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Steven Constantine, Jian Peng, and Lawrence D. Ziegler
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Birefringence ,Chemistry ,business.industry ,Physics::Optics ,Spectral density ,General Chemistry ,Polarization (waves) ,Dichroic glass ,Molecular physics ,symbols.namesake ,Optics ,symbols ,business ,Raman spectroscopy ,Ultrashort pulse - Abstract
The frequency selected dichroic ultrafast responses of neat carbon tetrachloride are reported as a function of pump and probe polarization orientations in a standard two beam experimental configuration. The recovery of the Raman spectral density from these experimental observations is demonstrated. The influence of coherent coupling effects, in this one color, electronically nonresonant class of ultrafast pump–probe experiments is considered. While their contribution to Raman spectral densities via birefringent observations can be neglected, these terms can only be eliminated from the dispersed dichroic technique for Raman spectral density recovery when two-color pump–probe studies are performed.
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- 2002
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45. Two-photon absorption resonance effects in the third-order responses of transparent liquids
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Lawrence D. Ziegler and X.J. Jordanides
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Chemistry ,Analytical chemistry ,General Physics and Astronomy ,Nonlinear optics ,Resonance ,Dichroic glass ,Polarization (waves) ,Molecular physics ,Two-photon absorption ,symbols.namesake ,Excited state ,symbols ,Physical and Theoretical Chemistry ,Raman spectroscopy ,Ground state - Abstract
Two-photon absorption (TPA) resonance effects on the ultrafast pump–probe and transient grating (TG) responses of some transparent liquids excited with 400 nm pulses are demonstrated. The contribution of TPA and ground state Raman responses are separated in a TG experiment when the third-order polarization signal is viewed in the appropriate phase-matched direction as shown for the homodyne, TG response of CS 2 . The pump–probe dichroic responses of liquids with (CS 2 and CH 3 I) and without (H 2 O, CCl 4 , and CH 3 OH) TPA resonances at 200 nm are compared. These results are discussed in the context of a perturbative third-order polarization treatment of TPA.
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- 2002
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46. Nonlinear optics in germanium mid-infrared fiber material: Detuning oscillations in femtosecond mid-infrared spectroscopy
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Mustafa Ordu, G. Ng Pack, Shyamsunder Erramilli, M. K. Hong, Parth P. Shah, Jicheng Guo, Lawrence D. Ziegler, Siddharth Ramachandran, and Soumendra N. Basu
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Optical fiber ,Materials science ,Physics::Optics ,General Physics and Astronomy ,chemistry.chemical_element ,Polarization-maintaining optical fiber ,Germanium ,02 engineering and technology ,01 natural sciences ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Fiber ,Nuclear Experiment ,Astrophysics::Galaxy Astrophysics ,business.industry ,Nonlinear optics ,021001 nanoscience & nanotechnology ,lcsh:QC1-999 ,chemistry ,Femtosecond ,Optoelectronics ,Photonics ,0210 nano-technology ,business ,lcsh:Physics ,Photonic-crystal fiber - Abstract
Germanium optical fibers hold great promise in extending semiconductor photonics into the fundamentally important mid-infrared region of the electromagnetic spectrum. The demonstration of nonlinear response in fabricated Ge fiber samples is a key step in the development of mid-infrared fiber materials. Here we report the observation of detuning oscillations in a germanium fiber in the mid-infrared region using femtosecond dispersed pump-probe spectroscopy. Detuning oscillations are observed in the frequency-resolved response when mid-infrared pump and probe pulses are overlapped in a fiber segment. The oscillations arise from the nonlinear frequency resolved nonlinear (χ(3)) response in the germanium semiconductor. Our work represents the first observation of coherent oscillations in the emerging field of germanium mid-infrared fiber optics.
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- 2017
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47. Platinum-Group Elements in Urban Fluvial Bed Sediments—Hawaii
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Alan D. Ziegler, Christopher Ottley, Ross A. Sutherland, and Graham Pearson
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Hydrology ,chemistry ,Urban stream ,Environmental chemistry ,chemistry.chemical_element ,Sediment ,Fractionation ,Iridium ,Platinum group ,Contamination ,Platinum ,Rhodium - Abstract
Results from a detailed examination of the abundance, spatial variability and grain-size fractionation of platinum-group elements (PGEs; iridium, Ir; palladium, Pd; platinum, Pt; and rhodium, Rh) in bed sediments of an urban stream in Honolulu (Hawaii, USA) indicate significant contamination of Pd, Pt, and Rh. PGE concentrations in sediments located in close proximity to storm drains followed the sequence of Pt (10.3–24.5 ng g−1) > Pd (5.9–12.6 ng g−1) > Rh (0.82–2.85 ng g−1) > Ir (0.11–0.23 ng g−1). From a contamination perspective, enrichment ratios followed the sequence of Rh (25.3) ≫ Pd (6.9) = Pt (6.8) ≫ Ir (2.3). Iridium was primarily geogenic in origin, while the remaining PGEs indicated significant anthropogenic contamination. Attrition of the PGE-loaded three-way catalytic converters and their release to the road environment is the most likely source of PGEs in the stream sediments examined. PGE enrichment of bed sediments likely resulted from direct transport of sediment-associated road runoff via storm drains. Preliminary work on grain-size partitioning showed preferential enrichment and mass loading of Pd, Pt, and Rh in grain-size fractions ranging from 63 to 1,000 μm. Data from this study have direct implications for contaminant transport, and sediment source identification in urban catchments. Rhodium, in particular, emerged as an element potentially useful for sediment fingerprinting.
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- 2014
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48. A Novel Technique for the Measurement of Polarization-Specific Ultrafast Raman Responses
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Lawrence D. Ziegler, Brian Space, S. Constantine, Y. Zhou, Xingdong Ji, and J. A. Gardecki
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Novel technique ,business.industry ,Chemistry ,Polarization (waves) ,symbols.namesake ,symbols ,Optoelectronics ,Cutoff ,Physics::Atomic Physics ,Time domain ,Physical and Theoretical Chemistry ,business ,Raman spectroscopy ,Ultrashort pulse - Abstract
A simple time domain method for the observation of polarization-specific Raman responses in electronically nonresonant materials is demonstrated. When a cutoff filter is placed in the probe beam pa...
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- 2001
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49. A unified treatment of ultrafast optical heterodyne detected and Z-scan spectroscopies
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Jian Peng, J. A. Gardecki, Lawrence D. Ziegler, Y. Zhou, S. Constantine, and G. Yu
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Birefringence ,Chemistry ,business.industry ,Physics::Optics ,General Physics and Astronomy ,Dichroism ,Polarization (waves) ,Optics ,Z-scan technique ,Physical and Theoretical Chemistry ,Time-resolved spectroscopy ,Spectroscopy ,business ,Refractive index ,Ultrashort pulse - Abstract
An analysis of femtosecond optical heterodyne detected (OHD) birefringence and dichroism is presented within the framework of the Z-scan technique previously developed for the measurement of nonlinear refractive indices. In particular, the phase of the effective local oscillator field, in the language of OHD spectroscopy, is shown to depend on the sample position (z) and the spatially detected portion of the signal pulse in the far field for nonresonant pump–probe responses due to focused Gaussian beams. Consequently, this treatment shows how the contributions of OHD birefringence and dichroism, and the corresponding homodyne signals, can best be separated in this simple two-beam experimental configuration and provides a description of the previously reported technique called position-sensitive Kerr lens spectroscopy. The nonresonant third-order polarization electronic response of fused silica illustrates this apertured OHD description. Spatial and frequency filtering results in ultrafast Z-scan responses that are dominated by dichroic and birefringent responses, respectively. An analysis of apertured OHD spectroscopy which incorporates a description of the optical phase fronts of the signal fields is required in order to exploit this relatively simple experimental technique for quantitative determinations of polarization-specific electronic responses and Raman nuclear spectral densities.
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- 2001
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50. Einfluss von Serum und osmotisch wirksamen Substanzen auf den Stoffwechsel in 262 Organkulturen der Kornea von Schweineaugen - Ein Beitrag zur Verbesserung des Spendermaterials zur Keratoplastik12
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Franz J. Pantenburg, Martin Reim, and Christoph D. Ziegler
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Metabolism ,Hydroxyethyl starch ,Biology ,Organ culture ,Andrology ,Ophthalmology ,chemistry.chemical_compound ,Dextran ,medicine.anatomical_structure ,Dry weight ,Biochemistry ,chemistry ,Cornea ,medicine ,Glycolysis ,Organ donation ,medicine.drug - Abstract
BACKGROUND The storage time of corneal organ cultures in limited in the closed system mainly used in European eye banks. In addition, swelling during storage reduces the quality of the donor material for keratoplasty. Therefore, dextrane was added in concentrations of 2.5%, 5%, 7.5% and 10% to the culture medium, and the energy producing metabolism was investigated. MATERIALS AND METHODS The experiments were carried out with 262 pig corneas. MEM with some supplements was used at 31 degrees C. No serum was added, because glucose consumption, lactate production and ATP levels proved to be the same or better than with serum supplement. After 6 and 12 days, the corneas from organ cultures were extracted with perchloric acid. The levels of glucose and lactate in the stroma and of ATP and ADP in the epithelium were analysed with enzymatic-optical tests. RESULTS Dextrane inhibited glycolysis and the production of ATP in corneal organ cultures during twelve days. With 7.5% and 10% dextrane in the medium, lactate levels in the cornea decreased from 6.09 to 4.5 and 4.6 microM/g H2O instead of increasing. At the same time, glucose increased paradoxical from 1.3 to 3.4 and 2.2 microM/g H2O, respectively. With 5% dextrane, glycolysis operated sufficiently producing an increase of lactate levels from 6.0 to 8.8 microM/g H2O and consuming glucose from levels of 1.27 down to 0.57 microM/g H2O. After 12 days with 7.5% and 10.0% dextrane, ATP levels were reduced, from 4.54 to 0.98 and 0.49 microM/g dry weight, and ATP/ADP ratios from 1.9 to 1.1 and 0.7 respectively. With 2.5% dextrane, the ATP was diminished from 4.5 to 2.2 microM/g dry weight. When 5% dextrane were added to the culture medium, the hydration was at optimum by 4.1, and ATP levels were reduced only from 4.5 to 2.6 microM/g dry weight. Moreover, the ATP/ADP ratios were at 2.1 as good as without dextrane. CONCLUSIONS From the results it was concluded, that serum free medium may be used, and that permanent dewelling proved to be beneficial for the energy producing metabolism of the cornea in organ culture. Such conditions may improve morphological and metabolic quality of donor material. From previous publications, it was recommended, to use instead of toxic dextran the well tolerated HES (hydroxyethyl starch) and to apply a storage temperature of 21 degrees C, which slowed down glucose consumption without impairing the energy producing metabolism.
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- 2001
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