John L Taylor

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• Taylor, J. L. (2009). On black men's diminishing existence in academe: An introspective view. Diversity in Higher Education, 7, 223-245.
• Taylor, J., Miller, B. W., Barber, H. B., Barrett, H. H., Chen, L., & Taylor, J. L. (2007). Photon-counting gamma camera based on columnar CsI(Tl) optically coupled to a back-illuminated CCD. Proceedings of SPIE, 6510.
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  Recent advances have been made in a new class of CCD-based, single-photon-counting gamma-ray detectors which offer sub-100 μm intrinsic resolutions.1-7 These detectors show great promise in small-animal SPECT and molecular imaging and exist in a variety of configurations. Typically, a columnar CsI(Tl) scintillator or a radiography screen (Gd(2)O(2)S:Tb) is imaged onto the CCD. Gamma-ray interactions are seen as clusters of signal spread over multiple pixels. When the detector is operated in a charge-integration mode, signal spread across pixels results in spatial-resolution degradation. However, if the detector is operated in photon-counting mode, the gamma-ray interaction position can be estimated using either Anger (centroid) estimation or maximum-likelihood position estimation resulting in a substantial improvement in spatial resolution.2 Due to the low-light-level nature of the scintillation process, CCD-based gamma cameras implement an amplification stage in the CCD via electron multiplying (EMCCDs)8-10 or via an image intensifier prior to the optical path.1We have applied ideas and techniques from previous systems to our high-resolution LumiSPECT detector.11, 12 LumiSPECT is a dual-modality optical/SPECT small-animal imaging system which was originally designed to operate in charge-integration mode. It employs a cryogenically cooled, high-quantum-efficiency, back-illuminated large-format CCD and operates in single-photon-counting mode without any intermediate amplification process. Operating in photon-counting mode, the detector has an intrinsic spatial resolution of 64 μm compared to 134 μm in integrating mode.
• Taylor, J., Mebrahtu, Y. B., Norem, J., & Taylor, J. L. (1997). Inheritance of larval resistance to permethrin in Aedes aegypti and association with sex ratio distortion and life history variation. The American journal of tropical medicine and hygiene, 56(4).
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  The genetic mechanisms that confer larval permethrin resistance were investigated in two strains of Aedes aegypti, vectors of yellow fever and dengue hemorrhagic fever. Larval resistance to permethrin in an Ae. aegypti field-collected resistant Couva (R) strain was associated with the sex-determining locus by analysis of backcrosses to the susceptible Rockefeller (S) strain. The median lethal concentrations (LC50s) of these strains were 23.1 (95% confidence interval = 22.0-24.3) and 2.2 (2.0-2.3) parts/billion of permethrin, respectively. The estimated resistance ratio (RR) for the R strain was 10.8 (10.3-11.4) compared with the S strain. Resistance was inherited as partly recessive (dominance [D] = -0.31) with an estimated RR of 2.3 (2.1-2.4) in the F1 hybrids when the R parent was male. There were also significantly male-biased sex ratios for this cross. In contrast, inheritance was slightly dominant (D = 0.19) with an estimated RR of 4.1 (3.8-4.4) when the R parent was female, and no significant sex ratio bias of progeny was observed. Analysis revealed a strong paternal-strain effect in bioassay mortality, sex ratio, egg hatch, and fecundity. A maternal-strain effect was also evident for bioassay mortality. Similarly, a strong maternal by paternal strain interaction was also evident for sex ratio. Progeny of single-family backcrosses of F1 hybrids to R were statistically homogeneous for sex ratio, duration of oviposition, fecundity, and hatch rate. A significant increase in male bias was found for only one backcross to R, after treatment with permethrin. In contrast, complex patterns of inheritance of life histories were observed among backcrosses to S. Backcrosses to S had greater mean fecundities, shorter mean times to the start of oviposition, and shorter mean oviposition periods than did backcrosses to R. Hatch rates were statistically homogeneous among backcrosses, but all strikingly reduced relative to the parental generation. Times of start and duration of oviposition were highly negatively correlated with fecundity (first gonotropic cycle only) and rate of egg hatch. Females with lower fecundities had lower hatch rates, and there was a threshold of approximately 80 eggs per female, below which no eggs hatched. Generally all backcrosses had higher LC50s than expected from single-locus inheritance. Association between sex bias and inheritance of resistance was apparent, but no single genetic linkage model based on current understanding of sex chromosome genetics was consistent with these observations. These results may have epidemiologic importance considering that permethrin-soaked bed nets are being used in many countries to control the biting activity of disease vectors.
• Taylor, J., Park, Y., & Taylor, J. L. (1997). A novel mutation L1029H in sodium channel gene hscp associated with pyrethroid resistance for Heliothis virescens (Lepidoptera:Noctuidae). Insect biochemistry and molecular biology, 27(1).
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  Sequencing of the sodium channel gene hscp (para-homologous) revealed that a T to A mutation encoding a Leu to His change (L1029H) is associated with pyrethroid resistance in populations of Heliothis virescens F. This mutation occurs at a position homologous to that of the mutation Leu to Phe (L1014F) reportedly associated with knock-down resistance (kdr) to pyrethroids in a house fly strain. Another mutation reportedly associated with super-kdr in house fly was not found in H. virescens samples. In previous work, we found that one haplotype Hpy3 of a marker locus Hpy that lies approximately 5 kb away from the L1029H polymorphism in the gene, increased in frequency among survivors of selection with pyrethroids, presumably through "hitch-hiking" with a resistance-conferring mutation. Not all resistant individuals examined in this study carried the L1029H mutation, but only those that also carried Hpy3 haplotypes. Resistance has been genetically linked to hscp markers for the strain PEG87, but this strain was found not to carry the L1029H mutation. Assuming that the L1029H mutation does in fact confer resistance, this suggests that more than one sodium channel mutation may be contributing to pyrethroid resistance in field populations of H. virescens.
• Taylor, J., Clark, L. C., Combs, G. F., Turnbull, B. W., Slate, E. H., Chalker, D. K., Chow, J., Davis, L. S., Glover, R. A., Graham, G. F., Gross, E. G., Krongrad, A., Lesher, J. L., Park, H. K., Sanders, B. B., Smith, C. L., & Taylor, J. L. (1996). Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. Nutritional Prevention of Cancer Study Group. JAMA : the journal of the American Medical Association, 276(24).
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  To determine whether a nutritional supplement of selenium will decrease the incidence of cancer.
• Taylor, J., Edwards, M. J., & Taylor, J. L. (1993). Substitution of DMSO for DMF as a solvent for X-gal. BioTechniques, 14(2).
• Taylor, J., Rutala, P. J., Witzke, D. B., Leko, E. O., Fulginiti, J. V., & Taylor, J. L. (1991). Sharing of information by students in an objective structured clinical examination. Archives of internal medicine, 151(3).
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  Increasing numbers of medical schools are using Objective Structured Clinical Examinations (OSCEs) to evaluate students. An Objective Structured Clinical Examination employs a multiple-station format and standardized patients to document students' clinical skills. A lengthy format is necessary; testing an entire class often necessitates multiple repetitions of the same examination. This dictates a need to minimize sharing of information among students. We studied six administrations of an Objective Structured Clinical Examination designed to measure skills. Analyses were conducted to detect changes in scores over the administrations as well as over the 8.5 hours of each day of testing. An increase in either might indicate information sharing had occurred. No significant increase occurred. If information was shared, it had no significant effect on scores. Skills a student uses to approach a patient should not change even if the patient's complaints are known.
• Taylor, J., Rutala, P. J., Witzke, D. B., Leko, E. O., Fulginiti, J. V., & Taylor, J. L. (1990). Student fatigue as a variable affecting performance in an objective structured clinical examination. Academic medicine : journal of the Association of American Medical Colleges, 65(9 Suppl).
• Taylor, J., Seals, D. R., Chase, P. B., & Taylor, J. L. (1988). Autonomic mediation of the pressor responses to isometric exercise in humans. Journal of applied physiology (Bethesda, Md. : 1985), 64(5).
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  The purpose of this study was to determine the respective contributions of tachycardia and increases in sympathetic nerve activity (SNA) in mediating the pressor responses to fatiguing vs. nonfatiguing levels of isometric handgrip exercise (IHE) in humans. We performed direct (microneurographic) measurements of muscle SNA from the right peroneal nerve in the leg and recorded arterial pressure (AP) and heart rate (HR) in eight healthy subjects before (control), during, and after 2.5 min of IHE at 15, 25, or 35% of maximal voluntary contraction (MVC). At 15% MVC, AP increased during the initial 1.5 min of IHE (7 mmHg, P less than 0.05) and remained at this level; at 25 and 35% MVC, AP increased throughout IHE (22 and 34 mmHg vs. control, respectively, P less than 0.05). HR increased during the initial 1.5 min of IHE at all three levels (5, 12, and 19 beats/min, respectively, P less than 0.05) but did not increase further over the last minute. At 15% MVC, muscle SNA did not increase above control; during 25 and 35% MVC, muscle SNA did not increase during the 1st min of IHE but increased progressively thereafter (109 and 205% vs. control, respectively, P less than 0.05). The magnitudes of the average increases in AP and muscle SNA over the last minute of IHE were directly related (r = 0.99, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
• Taylor, J. L. (1979). Development of the physical education observation instrument using generalizability study theory.. Research quarterly, 50(3), 468-481.
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  PMID: 545534;