TY - CONF TI - Evaluation of swine odor control products using human odor panels AU - Schiffman, S.S. AU - Williams, C.M. T2 - Animal Waste Management Symposium C2 - 1999/// C3 - Animal Waste Management Symposium DA - 1999/// PY - 1999/// SP - 110-118 PB - NC State University ER - TY - CONF TI - Development of the electronic nose for monitoring odors AU - Nagle, H.T. AU - Schiffman, S.S. AU - Gutierrez-Osuna, R. AU - Wyrick, D. T2 - Animal Waste Management Symposium C2 - 1999/// C3 - Animal Waste Management Symposium DA - 1999/// PY - 1999/// SP - 119-127 PB - NC State University ER - TY - CONF TI - Procedures to evaluate odor abatement products and technologies AU - Williams, C.M. AU - Schiffman, S.S. T2 - Animal Waste Management Symposium C2 - 1999/// C3 - Animal Waste Management Symposium DA - 1999/// PY - 1999/// SP - 99-109 PB - NC State University ER - TY - CONF TI - Effect of copper source and level on odor and performance of swine AU - Armstrong, T.A. AU - Williams, C.M. AU - Spears, J.W. AU - Schiffman, S.S. C2 - 1999/// C3 - Animal Waste Management Symposium DA - 1999/// SP - 239–242 PB - NC State University ER - TY - CONF TI - Quantitative measurement of odor AU - Raymer, J.H. AU - Schiffman, S.S. T2 - First NSF international conference on indoor air health. Impacts, issues, and solutions C2 - 1999/// C3 - Proceedings of the first NSF international conference on indoor air health. Impacts, issues, and solutions DA - 1999/// PY - 1999/// SP - 129–138 PB - NSF International ER - TY - JOUR TI - Future directions for use of odors in overall health AU - Schiffman, S.S. T2 - Aroma-Chology Review DA - 1999/// PY - 1999/// VL - 8 SP - 5, 11 ER - TY - JOUR TI - The essence of enhancement. Increasing residents’ health and quality of life while increasing revenue AU - Lucas, C. AU - Schiffman, S. T2 - National Investment Center Review DA - 1999/// PY - 1999/// VL - 7 SP - 35–41 ER - TY - JOUR TI - Effect of taste and smell on secretion rate of salivary IgA in elderly and young persons AU - Schiffman, S.S. AU - Miletic, I.D. T2 - Journal of Nutrition, Health, and Aging DA - 1999/// PY - 1999/// VL - 3 SP - 158–164 ER - TY - BOOK TI - Book review: Letters home: How writing can change your life AU - Schiffman, S.S. AU - Vance, Terry DA - 1999/3// PY - 1999/3// SE - 55 ER - TY - JOUR TI - Chemosensory Impairment and Appetite Commentary on "Impaired Sensory Functioning in Elders: The Relation With Its Potential Determinants and Nutritional Intake" AU - Schiffinan, S. S. T2 - The Journals of Gerontology Series A: Biological Sciences and Medical Sciences DA - 1999/8/1/ PY - 1999/8/1/ DO - 10.1093/gerona/54.8.b332 VL - 54 IS - 8 SP - B332-B333 J2 - The Journals of Gerontology Series A: Biological Sciences and Medical Sciences LA - en OP - SN - 1079-5006 1758-535X UR - http://dx.doi.org/10.1093/gerona/54.8.b332 DB - Crossref ER - TY - JOUR TI - Transient response analysis of an electronic nose using multi-exponential models AU - Gutierrez-Osuna, Ricardo AU - Nagle, H.Troy AU - Schiffman, Susan S. T2 - Sensors and Actuators B: Chemical AB - The purpose of this study is to model the transient response of conductivity-based gas sensors in the context of odor recognition with an electronic nose. Commonly, only the steady-state response of the sensor is used for pattern recognition, ignoring the transient response, which conveys useful discriminatory information. The transient response is modeled as a sum of real exponential functions that represent the different decay processes that occur during sampling of the gas into the sensor chamber and adsorption of the odor compounds onto the sensing element. Four multi-exponential models are reviewed: Gardner transform, multi-exponential transient spectroscopy, Pade-Laplace and Pade-Z transforms. Validation on experimental data from an array of conducting-polymer gas sensors shows that the Pade-Laplace and Pade-Z models have better resolution capabilities than the two spectral transforms. DA - 1999/12// PY - 1999/12// DO - 10.1016/s0925-4005(99)00290-7 VL - 61 IS - 1-3 SP - 170-182 J2 - Sensors and Actuators B: Chemical LA - en OP - SN - 0925-4005 UR - http://dx.doi.org/10.1016/s0925-4005(99)00290-7 DB - Crossref ER - TY - JOUR TI - Effect of protease inhibitors on the sense of taste AU - Schiffman, Susan S AU - Zervakis, Jennifer AU - Heffron, Sean AU - Heald, Alison E T2 - Nutrition AB - The purpose of this study was to investigate the taste properties of protease inhibitors which are essential components of drug regimes used to treat human immunodeficiency virus (HIV) infection. In this study, the taste properties of four protease inhibitors (indinavir, ritonavir, saquinavir, and nelfinavir) were investigated in unmedicated HIV-infected patients and healthy controls. Three of the four protease inhibitors (indinavir, ritonavir, and saquinavir) were found to be predominantly bitter (with additional qualities of medicinal, metallic, astringent, sour, and burning). Nelfinavir was found to be relatively tasteless. HIV-infected and uninfected control subjects detected protease inhibitors at similar concentrations, but HIV-infected subjects perceived suprathreshold concentrations as more bitter than controls. Detection thresholds ranged from 0.0061 mM for saquinavir in HIV-infected patients to 0.0702 mM for ritonavir in uninfected control subjects. Suprathreshold studies indicated that protease inhibitors modified the taste perception of a variety of other taste compounds. These results are consistent with clinical findings that protease inhibitors produce taste complaints that can impact patient compliance. DA - 1999/10// PY - 1999/10// DO - 10.1016/s0899-9007(99)00152-5 VL - 15 IS - 10 SP - 767-772 J2 - Nutrition LA - en OP - SN - 0899-9007 UR - http://dx.doi.org/10.1016/s0899-9007(99)00152-5 DB - Crossref ER - TY - JOUR TI - Effect of the nucleoside analogs zidovudine, didanosine, stavudine, and lamivudine on the sense of taste AU - Schiffman, Susan S AU - Zervakis, Jennifer AU - Shaio, Elizabeth AU - Heald, Alison E T2 - Nutrition AB - The purpose of this study was to investigate the taste properties of nucleoside analogs, which are among the current medications used to treat human immunodeficiency virus (HIV) infection. Eighteen unmedicated HIV-positive subjects and 41 healthy control subjects participated in threshold and suprathreshold experiments. All of the nucleoside medications tested were perceived as predominantly bitter (along with other qualities such as metallic, medicinal, sour, astringent, and cooling). The nucleoside analog with the lowest detection thresholds was zidovudine; the detection threshold was 1.47 mM for HIV-infected patients and 2.15 mM for control subjects. Detection thresholds for lamivudine were 4.41 mM for HIV-infected patients and 4.36 mM for control subjects. Detection thresholds for stavudine were 6.39 mM for HIV-infected patients and 5.99 mM for control subjects. Detection thresholds for didanosine were 14.29 mM for HIV-infected patients and 24.0 mM for control subjects. The nucleoside analogs also modified the taste perception of KCl and CaCl2. There were no significant differences between HIV-infected subjects and control subjects for detection threshold values for any of the drugs. However, HIV-infected subjects rated lamivudine, zidovudine, and stavudine as significantly more bitter than did the control subjects at concentrations four times higher than their detection thresholds. This result was not due to use of medications by HIV-infected subjects because none of the subjects (neither HIV-infected nor control) were taking medications. DA - 1999/11// PY - 1999/11// DO - 10.1016/s0899-9007(99)00182-3 VL - 15 IS - 11-12 SP - 854-859 J2 - Nutrition LA - en OP - SN - 0899-9007 UR - http://dx.doi.org/10.1016/s0899-9007(99)00182-3 DB - Crossref ER - TY - JOUR TI - Alterations of Chemosensory Function in End-Stage Liver Disease AU - Bloomfeld, Richard S AU - Graham, Brevick G AU - Schiffman, Susan S AU - Killenberg, Paul G T2 - Physiology & Behavior AB - Taste and smell dysfunction has been documented in patients with both acute and chronic liver disease. The purpose of this study was to determine if chemosensory function is improved after restoration of hepatic function with liver transplantation. Nine subjects (seven women and two men) with end-stage liver disease participated in the study. Taste and smell detection and recognition thresholds were determined before and after transplantation. A significant improvement in detection of the taste of sodium chloride and the odor of phenethyl alcohol was found after transplantation. These findings may have clinical significance in food choices and nutritional status of these patients. DA - 1999/4// PY - 1999/4// DO - 10.1016/s0031-9384(98)00266-2 VL - 66 IS - 2 SP - 203-207 J2 - Physiology & Behavior LA - en OP - SN - 0031-9384 UR - http://dx.doi.org/10.1016/s0031-9384(98)00266-2 DB - Crossref ER - TY - JOUR TI - Workshop on Taste and Smell in the Elderly AU - Finkelstein, Judith A AU - Schiffman, Susan S T2 - Physiology & Behavior AB - The purpose of the workshop entitled Taste and Smell in the Elderly: Behavioral and Nutritional Consequences was 1) to review the current state of knowledge in the area of taste and smell, with emphasis on age-related changes, 2) to identify existing gaps in our knowledge, and 3) to develop future research strategies. There was general agreement that the majority of scientific studies have found impairments in taste and smell acuity in the elderly. These losses may result from normal aging, certain disease states especially Alzheimer's disease, medications, surgical interventions, and environmental exposure. However, there are gaps in our knowledge of the basic mechanisms by which aging and environmental factors may impair the chemical senses in the elderly. Further research is also required in a variety of areas including chemosensory test procedures, food intake, and nutrition to understand fully the impact of chemosensory dysfunction on older individuals. DA - 1999/4// PY - 1999/4// DO - 10.1016/s0031-9384(98)00261-3 VL - 66 IS - 2 SP - 173-176 J2 - Physiology & Behavior LA - en OP - SN - 0031-9384 UR - http://dx.doi.org/10.1016/s0031-9384(98)00261-3 DB - Crossref ER - TY - JOUR TI - Effect of Medications on Taste AU - Schiffman, Susan S AU - Zervakis, Jennifer AU - Suggs, Mark S AU - Shaio, Elizabeth AU - Sattely–Miller, Elizabeth A T2 - Physiology & Behavior AB - Use of medications is a major factor that contributes to taste losses in the elderly. Epidemiological studies suggest that community-dwelling elderly over the age of 65 use an average of 2.9 to 3.7 medications, and this number increases significantly for elderly living in retirement and nursing homes. The tricyclic antidepressant amitriptyline HCl is used by at least half a million people aged 65 years or more. In human studies performed here, amitriptyline HCl was found to have a bitter, unpleasant taste of its own. In addition, it blocked responses to other taste stimuli in both humans and gerbils. This blockage in humans was greater when amitriptyline HCl was applied continuously to the tongue than when it was applied intermittently. Continuous application of the drug affected all of the taste qualities to varying degrees, while intermittent application led to taste decrements only for salts. Electrophysiological studies in gerbils also revealed taste decrements after a short adaptation to amitriptyline HCl. DA - 1999/4// PY - 1999/4// DO - 10.1016/s0031-9384(98)00263-7 VL - 66 IS - 2 SP - 183-191 J2 - Physiology & Behavior LA - en OP - SN - 0031-9384 UR - http://dx.doi.org/10.1016/s0031-9384(98)00263-7 DB - Crossref ER - TY - JOUR TI - Selective Inhibition of Sweetness by the Sodium Salt of +/-2-(4-Methoxyphenoxy)propanoic Acid AU - Schiffman, S. S. T2 - Chemical Senses AB - The purpose of this study was to determine the degree to which the sodium salt of± 2-(4-methoxyphenoxy)propanoic acid (Na-PMP) reduced sweet intensity ratings of 15 sweeteners in mixtures. Na-PMP has been approved for use in confectionary/ frostings, soft candy and snack products in the USA at concentrations up to 150 p.p.m. A trained panel evaluated the effect of Na-PMP on the intensity of the following 15 sweeteners: three sugars (fructose, glucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame), two N-sulfonylamides (acesulfame-K, sodium saccharin), two polyhydric alcohols (mannitol, sorbitol), 1 dihydrochalcone (neohesperidin dihydrochalcone), one protein (thaumatin) and one sulfamate (sodium cyclamate). Sweeteners were tested at concentrations isosweet with 2.5, 5, 7.5 and 10% sucrose in mixtures with two levels of Na-PMP: 250 and 500 p.p.m. In addition, the 15 sweeteners were tested either immediately or 30 s after a pre-rinse with 500 p.p.m. Na-PMP. In mixtures, Na-PMP at both the 250 and 500 p.p.m. levels significantly blocked sweetness intensity for 12 of the 15 sweeteners. However, when Na-PMP was mixed with three of the 15 sweeteners (monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin), there was little reduction in sweetness intensity. Pre-rinsing with Na-PMP both inhibited and enhanced sweetness with the greatest enhancements found for monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin, which were not suppressed by Na-PMP in mixtures. The mixture data suggest that Na-PMP is a selective competitive inhibitor of sweet taste. The finding that pre-treatment can produce enhancement may be due to sensitization of sweetener receptors by Na-PMP. DA - 1999/8/1/ PY - 1999/8/1/ DO - 10.1093/chemse/24.4.439 VL - 24 IS - 4 SP - 439-447 OP - SN - 1464-3553 UR - http://dx.doi.org/10.1093/chemse/24.4.439 DB - Crossref ER - TY - JOUR TI - Using neural networks and genetic algorithms to enhance performance in an electronic nose AU - Kermani, B.G. AU - Schiffman, S.S. AU - Nagle, H.T. T2 - IEEE Transactions on Biomedical Engineering AB - Sensitivity, repeatability, and discernment are three major issues in any classification problem. In this study, an electronic nose with an array of 32 sensors was used to classify a range of odorous substances. The collective time response of the sensor array was first partitioned into four time segments, using four smooth time windowing functions. The dimension of the data associated with each time segment as then reduced by applying the Karhunen-Loeve (truncated) expansion (KLE). An ensemble of the reduced data patterns was then used to train a neural network (NN) using the Levenberg-Marquardt (LM) learning method. A genetic algorithm (GA)-based evolutionary computation method was used to devise the appropriate NN training parameters, as well as the effective database partitions/features. Finally, it was shown that a GA supervised NN system (GANN) outperforms the NN-only classifier, for the classes of the odorants investigated in this study (fragrances, hog farm air, and soft beverages). DA - 1999/4// PY - 1999/4// DO - 10.1109/10.752940 VL - 46 IS - 4 SP - 429-439 J2 - IEEE Trans. Biomed. Eng. OP - SN - 0018-9294 UR - http://dx.doi.org/10.1109/10.752940 DB - Crossref ER - TY - JOUR TI - Subunit analyses of a novel thermostable glucose dehydrogenase showing different temperature properties according to its quaternary structure AU - Yamazaki, T AU - Tsugawa, W AU - Sode, K T2 - Applied Biochemistry and Biotechnology DA - 1999/// PY - 1999/// DO - 10.1385/ABAB:77:1-3:325 VL - 77-9 SP - 325-335 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000081133100031&KeyUID=WOS:000081133100031 KW - glucose dehydrogenase KW - thermal stability KW - catalytic subunit KW - electron transfer subunit KW - quaternary structures ER - TY - JOUR TI - Site-directed mutagenesis study on the thermal stability of a chimeric PQQ glucose dehydrogenase and its structural interpretation AU - Witarto, AB AU - Ohtera, T AU - Sode, K T2 - Applied Biochemistry and Biotechnology DA - 1999/// PY - 1999/// DO - 10.1385/ABAB:77:1-3:159 VL - 77-9 SP - 159-168 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000081133100017&KeyUID=WOS:000081133100017 KW - PQQ glucose dehydrogenase KW - beta-propeller protein KW - site-directed mutagenesis KW - CD spectroscopy KW - denaturation pathway ER - TY - JOUR TI - Single amino acid preferences for specific locations at type-I alpha-turns in globular proteins AU - Narita, M AU - Sode, K AU - Ohuchi, S T2 - Bulletin of the Chemical Society of Japan AB - Abstract Using both dihedral angles and hydrogen-bond definitions, 225 type-I α-turns were extracted from 125 analyzed proteins. The extracted α-turns were built up from 5% (1125) of the total amino acid residues (23286) found in the proteins. The type-I α-turn is an independent kind of secondary structural unit, although it has been frequently classified as (i, i+1) double β-turns. Both the nucleation of a helix with the type-I β-turn and its propagation with the repetitive addition of the type-I β-turn suggest that the origin of the helix in a globular protein might be the type-I β-turn. Single amino acid preferences for specific locations at type-I α-turns were compared to those at type-I β-turns and the ends of helices. The result indicates that the type-I α-turn, the type-I β-turn, and the helix are of similar kin. Similarities in the structure and amino acid preferences for specific locations among them suggest that the amino acid residues on defined positions along both turns could be properly assigned to the corresponding helix elements. DA - 1999/// PY - 1999/// DO - 10.1246/bcsj.72.1807 VL - 72 IS - 8 SP - 1807-1813 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000082370300018&KeyUID=WOS:000082370300018 ER - TY - JOUR TI - Secondary structure study of pyrroloquinoline quinone glucose dehydrogenase AU - Witarto, A.B. AU - Oh-Uchi, S. AU - Narita, M. AU - Sode, K. T2 - Journal of Biochemistry, Molecular Biology and Biophysics DA - 1999/// PY - 1999/// VL - 2 IS - 3 SP - 209-213 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032956367&partnerID=MN8TOARS ER - TY - JOUR TI - Increased thermal stability of glucose dehydrogenase by cross-linking chemical modification AU - Yamazaki, T AU - Tsugawa, W AU - Sode, K T2 - Biotechnology Letters DA - 1999/// PY - 1999/// DO - 10.1023/A:1005455911753 VL - 21 IS - 3 SP - 199-202 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000079992000004&KeyUID=WOS:000079992000004 KW - thermal stabilization KW - glucose dehydrogenase KW - cross-linking chemical modification KW - amperometric glucose sensor KW - storage stability ER - TY - JOUR TI - Engineering a chimeric pyrroloquinoline quinone glucose dehydrogenase: improvement of EDTA tolerance, thermal stability and substrate specificity AU - Yoshida, H AU - Kojima, K AU - Witarto, AB AU - Sode, K T2 - Protein Engineering AB - An engineered Escherichia coli PQQ glucose dehydrogenase (PQQGDH) with improved enzymatic characteristics was constructed by substituting and combining the gene-encoding protein regions responsible for EDTA tolerance, thermal stability and substrate specificity. The protein region responsible for complete EDTA tolerance in Acinetobacter calcoaceticus, which is recognized as the indicator of high stability in co-factor binding, was elucidated. The region is located between 32 and 59% from the N-terminus of A. calcoaceticus PQQGDH(A27 region) and also corresponds to the same position from 32 to 59% from the N-terminus in E. coli PQQGDH, though E. coli PQQGDH is EDTA sensitive. We previously reported that the C-terminal 3% region of A. calcoaceticus (A3 region) played an important role in the increase of thermal stability, and that His775Asn substitution in E. coli PQQGDH resulted in an increase in the substrate specificity of E. coli PQQGDH towards glucose. Based on these findings, chimeric and/or mutated PQQGDHs, E97A3 H775N, E32A27E41 H782N, E32A27E38A3 and E32A27E38A3 H782N were constructed to investigate the compatibility of two protein regions and one amino acid substitution. His775 substitution to Asn corresponded to His782 substitution to Asn (H782N) in chimeric enzymes harbouring the A27 region. Since all the chimeric PQQGDHs harbouring the A27 region were EDTA tolerant, the A27 region was found to be compatible with the other region and substituted amino acid responsible for the improvement of enzymatic properties. The contribution of the A3 region to thermal stability complemented the decrease in the thermal stability due to the His775 or His782 substitution to Asn. E32A27E38A3 H782N, which harbours all the above mentioned three regions, showed improved EDTA tolerance, thermal stability and substrate specificity. These results suggested a strategy for the construction of a semi-artificial enzyme by substituting and combining the gene-encoding protein regions responsible for the improvement of enzyme characteristics. The characteristics of constructed chimeric PQQGDH are discussed based on the predicted model, beta-propeller structure. DA - 1999/// PY - 1999/// DO - 10.1093/protein/12.1.63 VL - 12 IS - 1 SP - 63-70 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000078450700010&KeyUID=WOS:000078450700010 KW - PQQ glucose dehydrogenase KW - chimeric enzymes KW - biosensor KW - substrate specificity KW - thermal stability ER - TY - JOUR TI - Effect of growth substrates on production of new soluble glucose 3-dehydrogenase in Halomonas (Deleya) sp alpha-15 AU - Kojima, K AU - Tsugawa, W AU - Hamahuji, T AU - Watazu, Y AU - Sode, K T2 - Applied Biochemistry and Biotechnology DA - 1999/// PY - 1999/// VL - 77-9 SP - 827-834 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000081133100076&KeyUID=WOS:000081133100076 ER - TY - JOUR TI - Design of new primers that can detect Salmonella without decrease of detection threshold in the presence of contaminant organisms AU - Takeuchi, A AU - Sode, K T2 - Biotechnology Techniques DA - 1999/// PY - 1999/// DO - 10.1023/A:1008851814727 VL - 13 IS - 1 SP - 81-85 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000079281000016&KeyUID=WOS:000079281000016 KW - Salmonella KW - Citrobacter KW - PCR KW - primer KW - threshold ER - TY - JOUR TI - Construction and characterization of mutant water-soluble PQQ glucose dehydrogenases with altered K-m values - Site-directed mutagenesis studies on the putative active site AU - Igarashi, S AU - Ohtera, T AU - Yoshida, H AU - Witarto, AB AU - Sode, K T2 - Biochemical and Biophysical Research Communications AB - Based on a PCR mutant enzyme of water-soluble glucose dehydrogenase-harboring pyrroloquinoline quinone as the prosthetic group, PQQGDH-B, a site-directed mutagenesis study was carried out. The substitution of Glu277 residue with Gly resulted in a decrease in the K(m) value for glucose and altered the substrate specificity profile, compared with the wild-type enzyme. Mutational analyses on the neighboring amino acid residues of Glu277 were also carried out and constructed Asp275Glu, Asp276Glu, Ile278Phe, and Asn279His. Considering that Asp275Glu, Asp276Glu and also Glu277Gly showed drastic decreases in EDTA tolerance, this region may construct a PQQGDH-B putative active site, such as a binding site for Ca(2+), which is responsible for the binding PQQ. A series of Glu277 variants, Glu277 substituted by Ala, Val, Asp, Asn, His, Gln, or to Lys, was constructed and they all showed decreased K(m) values and altered substrate specificity profiles. Among them, Glu277Lys showed similar thermal stability with the wild-type enzyme, but its catalytic efficiency increased significantly, compared with the wild-type enzyme. The potential applications of Glu277Lys in analytical use are also discussed. DA - 1999/// PY - 1999/// DO - 10.1006/bbrc.1999.1157 VL - 264 IS - 3 SP - 820-824 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000083666200037&KeyUID=WOS:000083666200037 KW - pyrroloquinoline quinone (PQQ) KW - glucose dehydrogenase KW - s-GDH KW - catalytic activity KW - biosensor ER - TY - JOUR TI - Construction and characterization of fermentative lactate dehydrogenase Escherichia coli mutant and its potential for bacterial hydrogen production AU - Sode, K AU - Watanabe, M AU - Makimoto, H AU - Tomiyama, M T2 - Applied Biochemistry and Biotechnology DA - 1999/// PY - 1999/// DO - 10.1385/ABAB:77:1-3:317 VL - 77-9 SP - 317-323 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000081133100030&KeyUID=WOS:000081133100030 KW - metabolic engineering KW - lactate dehydrogenase KW - hydrogen KW - production KW - Escherichia coli ER - TY - JOUR TI - Construction and characterization of a linked-dimeric pyrroloquinoline quinone glucose dehydrogenase AU - Sode, K AU - Shirahane, M AU - Yoshida, H T2 - Biotechnology Letters DA - 1999/// PY - 1999/// DO - 10.1023/A:1005518610946 VL - 21 IS - 8 SP - 707-710 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000082440800012&KeyUID=WOS:000082440800012 KW - biosensor KW - glucose dehydrogenase KW - protein engineering KW - pyrroloquinoline quinone ER - TY - JOUR TI - Preparation and mechanical properties of composite diamond-like carbon thin films AU - Wei, Q AU - Narayan, RJ AU - Sharma, AK AU - Sankar, J AU - Narayan, J T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS AB - We have investigated mechanical properties of diamond-like carbon (DLC) thin films, particularly the internal compressive stress and ways to alleviate it. Foreign atoms such as copper, titanium, and silicon were incorporated into the DLC films during pulsed laser deposition. The chemical composition of the doped films was determined using Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy (XPS). Optical microscopy of the doped films showed that DLC films containing Cu exhibit much less particulate density as compared to the films containing Ti and Si. Visible Raman spectroscopy was used to characterize the films. The effect of dopants on the Raman spectrum was analyzed in terms of peak shape and position. Optical microscopy of the pure DLC of a certain thickness showed severe buckling. The mechanisms of adhesion associated with DLC coatings were discussed. Qualitative scratch tests on the specimens showed that pure DLC films have relatively poor adhesion due to a large compressive stress, while the doped DLC films exhibit much improved adhesion. Wear tests show improved wear resistance in the doped DLC coatings. Nanoindentation results suggest that pure DLC has an average hardness above 40 GPa and effective Young’s modulus above 200 GPa. The doped DLC films showed slightly decreased hardness and Young’s modulus as compared to pure DLC films. These results can be rationalized by analyzing the internal stress reduction as derived from Raman G-peak shift to lower wavenumbers. A preliminary interpretation of the stress reduction mechanism is discussed. DA - 1999/// PY - 1999/// DO - 10.1116/1.582074 VL - 17 IS - 6 SP - 3406-3414 SN - 0734-2101 ER - TY - JOUR TI - Diamond films and composites on cobalt-chromium alloys AU - Godbole, VP AU - Narayan, R AU - Xu, Z AU - Narayan, J AU - Sankar, J T2 - MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY AB - Abstract Silicon, aluminum nitride (AlN) and titanium carbide (TiC) layers were deposited on cobalt–chromium alloys to investigate their utility as buffer layers for the synthesis of diamond films and composites. Silicon and aluminum nitride were found to react with the substrate at diamond deposition temperatures, via out-diffusion of cobalt from the substrate. The layers of titanium carbide, on the other hand, were found to be useful as a diffusion barrier for outward diffusion of cobalt and inward diffusion of carbon during diamond deposition, thus making enhanced nucleation and growth of high quality diamond possible. The continuous diamond coatings thus formed, however, tend to bulge and then crack due to thermal expansion mismatches between the TiC coated substrate and the overlayer diamond film. Composite coatings of AlN–diamond and TiC–diamond have, therefore, been synthesized by sequential deposition of component materials. These composite coatings consist of randomly interconnected micron sized diamond crystallites which are primarily surrounded by buffer material (AlN or TiC) while the contact area between neighbouring diamond crystallites is minimum. The presence of such a discontinuous morphology of diamond crystallites renders more toughness and also leads to compensation of stresses in localized regions (local stress management) and thus reduces bulging and subsequent delamination effects. DA - 1999/3/29/ PY - 1999/3/29/ DO - 10.1016/s0921-5107(98)00430-9 VL - 58 IS - 3 SP - 251-257 SN - 0921-5107 KW - alloy KW - cobalt-chromium KW - composite KW - diamond ER -