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Coccobius abdominis Huang 1994
No full textCoccobius abdominis Huang 1994 (Figs 1–9) Coccobius abdominis Huang, 1994: 161. Material examined. Holotype female. China: Fujian, Fuzhou, Jinshan, 1987 (coll. Nai-Quan Lin), by yellow pan trap, (FAFU). Paratypes. 1 ♀, China: Fujian, Fuzhou, Forest Park, 23 June 1989 (coll. Zhi-Shan Wu), by sweeping; 1 ♀, China: Fujian, Fuzhou, Forest Park, 5 November 1989 (coll. Jian-Qing Huang), by yellow sticky trap, (FAFU). Additional specimen, 1 ♀, China: Fujian, Fuzhou, Jinshan, 30 September 2013 (coll. Zhu-Hong Wang), ex. diaspidid scale on bamboo. Female. Body length: 0.59 (0.65–0.79) mm. Colour. Head and mesosoma dark brown, metasoma pale yellow; mandible dark brown to black brown. Antenna with basal three-fifths of scape dark brown, apex of scape pale brown, pedicel and flagellum pale yellow. Wings hyaline. Legs pale yellow, fore coxae dark basally and hind coxae slightly darkened basally. Third valvula pale yellow. Head. Vertex with reticulate sculpture; eyes finely setose; Antennal scape about 3.78 × (3.57 –4.00×) as long as wide; pedicel 1.50 × (1.40 ×) as long as wide, 0.89 × (0.87–0.90 ×) as long as F 1; F 1 subequal in length to F 2, 0.88 × (0.89 ×) as long as F 3; F 1 –F 3 2.00×, 1.78 × and 1.73 × as long as wide respectively, each with 2 or 3 longitudinal sensilla; clava shorter than funicle; C 1 1.32 × (1.47–1.54 ×) as long as wide, subequal in length to F 3; C 2 2.05 × (2.36–2.66 ×) as long as wide, 1.54 × (1.44–1.78 ×) as long as C 1, each with 3 or 4 longitudinal sensilla. Mesosoma. Mid-lobe of mesoscutum mostly with irregularly hexagonal cells or reticulation, except transverse reticulation posterolaterally, with 22 (14–20) setae; distance between axillae 2.82 × (3.00×) length of an axilla; mesoscutellum 0.75 × (0.86 ×) as long as mid–lobe of mesoscutum, with longitudinal reticulation medially and irregularly hexagonal cells or reticulation laterally, with 2 pairs of setae, and placoid sensilla closer to fore pair of setae than to hind pair; metanotum with faint reticulation medially; propodeum reticulate except faint medially; mesopostphragma, measured from apex of mesoscutellum, 1.39 × (1.11–1.32 ×) as long as mesoscutellum. Fore wing 3.04 × (3.03–3.35 ×) as long as maximum width of wing disc; marginal fringe 0.35 × (0.26–0.35 ×) as long as maximum width of disc; submarginal vein shorter than marginal vein, with 7 (7 or 8) setae; marginal vein with 9 (8 or 9) setae along anterior margin; postmarginal vein absent; wing disc densely setose with narrow asetose area posterobasally. Metasoma. Metasoma slightly shorter than mesosoma; tergites 1–7 with setae as follows: T 1 –T4, 1+ 1 each; T5, 2+ 2; T6, 4 between cercal plates; T7, 7 in two rows; ovipositor basally located at T 3, slightly projecting beyond apex of metasoma, 1.41 × (1.42 ×) as long as mid tibia, third valvula 1.94 × (1.47–1.57 ×) as long as mid basitarsus. Male. Unknown. Host. An unidentified Diaspididae (Hemiptera) scale on bamboo. Distribution. China (Fujian). Diagnosis. Coccobius abdominis differs from other species of the genus by the head and mesosoma being dark brown and the metasoma completely pale yellow in combination with the antennal pedicel and flagellum being pale yellow.Published as part of Wang, Zhu-Hong, Huang, Jian & Polaszek, Andrew, 2014, Three new species of Coccobius Ratzeburg (Hymenoptera, Aphelinidae) and redescription of C. abdominis Huang and C. furviflagellatus Huang from China, pp. 460-472 in Zootaxa 3774 (5) on pages 462-463, DOI: 10.11646/zootaxa.3774.5.4, http://zenodo.org/record/22456
Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Analyse des signaux multicomposante à modulation de fréquence linéaire par la transformation de Teager-Huang-Hough
Get PDFA novel detection approach of linear FM (LFM) signals, with single or multiple components, in the time-frequency plane of Teager-Huang (TH) transform is presented. The detection scheme that combines TH transform and Hough transform is referred to as Teager-Huang-Hough (THH) transform. The input signal is mapped into the time-frequency plane by using TH transform followed by the application of Hough transform to recognize time-frequency components. LFM components are detected and their parameters are estimated from peaks and their locations in the Hough space. Advantages of THH transform over Hough transform of Wigner-Ville distribution (WVD) are: 1) cross-terms free detection and estimation, and 2) good time and frequency resolutions. No assumptions are made about the number of components of the LFM signals and their models. THH transform is illustrated on multicomponent LFM signals in free and noisy environments and the results compared with WVD-Hough and pseudo-WVD-Hough transforms
Atmospheric histories and growth trends of C[subscript 4]F[subscript 10], C[subscript 5]F[subscript 12], C[subscript 6]F[subscript 14], C[subscript 7]F[subscript 16] and C[subscript 8]F[subscript 18]
Get PDFAtmospheric observations and trends are presented for the high molecular weight perfluorocarbons (PFCs): decafluorobutane (C[subscript 4]F[subscript 10]), dodecafluoropentane (C[subscript 5]F[subscript 12]), tetradecafluorohexane (C[subscript 6]F[subscript 14]), hexadecafluoroheptane (C[subscript 7]F[subscript 16]) and octadecafluorooctane (C[subscript 8]F[subscript 18]). Their atmospheric histories are based on measurements of 36 Northern Hemisphere and 46 Southern Hemisphere archived air samples collected between 1973 to 2011 using the Advanced Global Atmospheric Gases Experiment (AGAGE) "Medusa" preconcentration gas chromatography-mass spectrometry systems. A new calibration scale was prepared for each PFC, with estimated accuracies of 6.8% for C[subscript 4]F[subscript 10], 7.8% for C[subscript 5]F[subscript 12], 4.0% for C[subscript 6]F[subscript 14], 6.6% for C[subscript 7]F[subscript 16] and 7.9% for C[subscript 8]F[subscript 18]. Based on our observations the 2011 globally averaged dry air mole fractions of these heavy PFCs are: 0.17 parts-per-trillion (ppt, i.e., parts per 10[superscript 12]) for C[subscript 4]F[subscript 10], 0.12 ppt for C[subscript 5]F[subscript 12], 0.27 ppt for C[subscript 6]F[subscript 14], 0.12 ppt for C[subscript 7]F[subscript 16] and 0.09 ppt for C[subscript 8]F[subscript 18]. These atmospheric mole fractions combine to contribute to a global average radiative forcing of 0.35 mW m[superscript −2], which is 6% of the total anthropogenic PFC radiative forcing (Montzka and Reimann, 2011; Oram et al., 2012). The growth rates of the heavy perfluorocarbons were largest in the late 1990s peaking at 6.2 parts per quadrillion (ppq, i.e., parts per 10[superscript 15]) per year (yr) for C[subscript 4]F[subscript 10], at 5.0 ppq yr−1 for C[subscript 5]F[subscript 12] and 16.6 ppq yr[superscript −1] for C[subscript 6]F[subscript 14] and in the early 1990s for C7F16 at 4.7 ppq yr−1 and in the mid 1990s for C8F18 at 4.8 ppq yr−1. The 2011 globally averaged mean atmospheric growth rates of these PFCs are subsequently lower at 2.2 ppq yr[superscript −1] for C[subscript 4]F[subscript 10], 1.4 ppq yr[superscript −1] for C[subscript 5]F[subscript 12], 5.0 ppq yr[superscript −1] for C[subscript 6]F[subscript 14], 3.4 ppq yr[superscript −1] for C[subscript 7]F[subscript 16] and 0.9 ppq yr[superscript −1] for C[subscript 8]F[subscript 18]. The more recent slowdown in the growth rates suggests that emissions are declining as compared to the 1980s and 1990s.NASA Upper Atmospheric Research Program (Grant number NNX11AF17G
Aceria gallae T. Huang 1996
No full textAceria gallae T. Huang, 1996 (Fig. 2) Aceria gallae T. Huang, 1996: 82, fig. 1 Female: (n= 4) Body worm-like, 123 long; prodorsal shield 23 long, 27 wide, anterior lobe present; prodorsal shield design with median lines complete, admedian line from basal one-fourth to half, concave at basal twofifths and convex at basal one-third, submedian lines convex at half; scapular tubercles set at prodorsal shield rear margin, setae (sc) 22 long, directed backward, sct-sct 14 apart; leg segments normal, foretibial seta (1 ') absent; 1 st coxal setae (1 b) 7 long, 1 bt- 1 bt 6 apart, 2 nd coxal setae (1 a) 11 long, 1 at- 1 at 7 apart, 3 rd coxal setae (2 a) 16 long, 2 at- 2 at 17 apart; solenidion ending as a knob; empodium simple, 4 -rayed. Opisthosoma: with about 78 microtuberculate rings, rear rings broader than anterior rings; first 3 rings 4 long; lateral setae (c 2) 15 long, c 2 t-c 2t 36 apart, c 2t \dt 37, c 2 t-dt 19; 1 st ventral setae (d) 21 long, dt-dt 28 apart, dt\et 31, dt-et 21; 2 nd ventral setae (e) 6 long, et-et 18 apart, et\ft 43, et-ft 39; 3 rd ventral setae (f) 20 long, ft-ft 14 apart; setae h 1 present. Coverflap: 17 wide, 11 long, with about 8 longitudinal lines, genital setae (3 a) 5 long, 3 at- 3 at 11 apart. Male: not seen. Specimens examined: 4 females, Tucheng, Taipei; 23 -Dec.- 1995, G. S. Tung; 5 females, Jhushan, Nantou, 20 -Aug.- 1995, K. W. Huang; 10 -Dec.- 1998, Dakan, Taichung, K. W. Huang; ex. Cordia dichotoma Forst. (Boraginaceae). Relation to host: Mites form cylindrical galls on the upper surface of leaf and erineum on the lower surface. Distribution: Taiwan.Published as part of Huang, Kun-Wei, 2008, Aceria (Acarina: Eriophyoidea) in Taiwan: five new species and plant abnormalities caused by sixteen species, pp. 1-30 in Zootaxa 1829 on pages 5-7, DOI: 10.5281/zenodo.18316
Coccobius jinshanensis Wang, Huang & Polaszek, sp. nov.
No full textCoccobius jinshanensis Wang, Huang & Polaszek, sp. nov. (Figs 38–46) Type material. Holotype female. China: Fujian, Fuzhou, Jinshan, June 2013 (coll. Yan-Hua Li), ex. a diaspidid scale (Hemiptera: Diaspididae) on bamboo. Deposited as a slide-mounted specimen in College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China (FAFU). Female. Body length: 0.81 mm. Colour. Head mostly brown to blackish brown except frontovertex dark yellow; mandible dark brown. Pronotum and axilla dark to blackish brown; mid-lobe of mesoscutum dark yellow with a dark brown patch on each side and a short dark brown stripe in posterior half centrally; side-lobe of mesoscutum dark yellow to dark brown; mesoscutellum mostly dark yellow with margins brown to dark brown; metanotum and propodeum brown to dark brown except middle white; prosternum and mesopleuron dark to blackish brown; mesosternum and metasternum mostly yellow. Metasoma pale yellow with rather sharply defined blackish brown bands on each side from the base to cercal plates. Antenna with radicle, basal half of scape, F 1 and clava brown to dark brown; apical half of scape, pedicel, F 2 and F 3 pale yellow. Wings hyaline. Legs white to pale yellow. Third valvula pale yellow. Head. Vertex with reticulate sculpture; eyes finely setose. Antennal scape about 3.50 × as long as wide; pedicel 1.80 × as long as wide, subequal in length to F 1; F 1 2.14 × as long as wide, 0.85 × and 0.82 × as long as F 2 and F 3 respectively, F 2 2.30 × as long as wide, slightly shorter than (0.96 × as long as) F 3, F 3 2.20 × as long as wide, each funicular segment with 1 or 2 longitudinal sensilla; clava slightly shorter than (0.97 × as long as) funicle, C 1 2.70 × as long as wide, C 2 3.50 × as long as wide, distinctly longer than (1.53 × as long as) C 1, each claval segment with 2– 4 longitudinal sensilla. Mesosoma. Mid-lobe of mesoscutum with faint reticulation, with 44 setae; distance between axillae about 2.9 × length of an axilla; mesoscutellum 0.90 × as long as mid-lobe of mesoscutum, with distinctly longitudinal reticulation and with 3 pairs of setae, placoid sensilla close to mid pair of setae; mesopostphragma, measured from apex of mesoscutellum, subequal in length to mesoscutellum. Fore wing 2.70 × as long as maximum width of wing disc; marginal fringe short, 0.15 × as long as maximum width of wing disc; submarginal vein shorter than marginal vein, with 7 setae; marginal vein with 11 setae along anterior margin; postmarginal vein absent; wing disc densely setose with narrow asetose area posterobasally. Metasoma. Metasoma subequal in length to mesosoma; tergites 1–7 with setae as follows: T1, 1+ 1; T2, 4+ 3; T3, 4+ 4; T4, 4+ 4; T5, 3+ 3; T6, 5 between cercal plates; T7, 12 in three rows; ovipositor basally located at T 3, slightly projecting beyond apex of metasoma, 1.70 × as long as mid tibia; third valvula 3.20 × as long as mid basitarsus. Male. Unknown. Host. An unidentified Diaspididae (Hemiptera) scale on bamboo. Distribution. China (Fujian). Etymology. The specific designation jinshanensis is derived from the place name, Jinshan area, where the new species was collected. Diagnosis. Coccobius jinshanensis resembles C. maculatus Huang 1994, which keys to couplet 14 in the key to Chinese species given by Wang et al. (2014), but can be differentiated from the latter by the following: head with frontovertex dark yellow; mid-lobe of mesoscutum dark yellow with a dark brown patch on each side and a short dark brown stripe in posterior half medially; mesoscutellum mostly dark yellow with margins brown to dark brown; and antenna with flagellum relatively slender, F 1 –F 3 2.14–2.30 × and C 1 –C 2 2.7–3.50 × as long as wide respectively, F 1 shorter than (0.85 × and 0.82 × as long as) F 2 and F 3 respectively. In C. maculatus the head, midlobe of mesoscutum and mesoscutellum are dark brown and the flagellum is not slender, with F 1 –F 3 1.50–1.92 × and C 1 –C 2 1.35–2.33 × as long as wide respectively, and F 1 longer than (1.10 × as long as) F 2 and F 3 respectively. Coccobius jinshanensis also resembles C. aligarhensis Hayat 1974, but can be differentiated from the latter by the following: the mesoscutellum mostly dark yellow; antenna with radicle, basal half of scape, F 1 and clava brown to dark brown; apical half of scape, pedicel, F 2 and F 3 pale yellow. In C. aligarhensis the mesoscutellum has a large dark brown patch on each side and the scape is brown except its apex and the remainder of the antenna is pale yellow.Published as part of Wang, Zhu-Hong, Huang, Jian & Polaszek, Andrew, 2014, Three new species of Coccobius Ratzeburg (Hymenoptera, Aphelinidae) and redescription of C. abdominis Huang and C. furviflagellatus Huang from China, pp. 460-472 in Zootaxa 3774 (5) on page 468, DOI: 10.11646/zootaxa.3774.5.4, http://zenodo.org/record/22456
Coccobius leptocerus Wang, Huang & Polaszek, sp. nov.
No full textCoccobius leptocerus Wang, Huang & Polaszek, sp. nov. (Figs 47–58) Type material. Holotype female. China: Guangxi, Nanning, 29 December 2012 (coll. Zhu-Hong Wang & Jian Huang), ex. a diaspidid scale in the leaf sheath of bamboo. Deposited as a slide mounted specimen in College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China (FAFU). Paratype, 1 ♀, with same data as holotype, but collected on surface of a leaf of a tree at the same place (FAFU). Female. Body length: 1.49 mm. Colour. Body yellow to brownish yellow, metasoma with T 1 –T 4 and sterna 1–4 brownish yellow in middle and brown to dark brown on sides, T 5 mostly brown to dark brown; mesopleuron brownish yellow to brown; mandible dark brown; eyes pale grey, ocelli brownish red. Antenna with radicle, base of F 1 dark brown; scape, pedicel, remainder of F 1, F 2 pale yellow; F 3 and clava pale yellow to brownish yellow. Wings hyaline. Legs pale yellow, fore and hind tibiae and femora brown, mid tibia and femur pale yellow. Third valvula apically dark brown. Head. Vertex with reticulate sculpture; eyes finely setose; mandible with 3 teeth. Antennal scape about 4.03 × as long as wide; pedicel short, 0.54 × as long as F 1; F 1 and F 2 distinctly longer, F 1 3.36 × as long as wide, slightly longer than (1.06 × as long as) F 2, F 2 3.28 × as long as wide, 1.14 × as long as F 3, F 3 2.42 × as long as wide, F 1 –F 3 with 3 or 4 longitudinal sensilla respectively; clava distinctly shorter than funicle, C 1 1.63 × as long as wide, C 2 2.81 × as long as wide, distinctly longer than C 1, each claval segment with 6 or 7 longitudinal sensilla. Mesosoma. Mid-lobe of mesoscutum with irregular hexagonal cells or reticulation, except faint medially, with 43 setae; distance between axillae about 2.27 × the length of an axilla; mesoscutellum 0.74 × as long as mid-lobe of mesoscutum, with longitudinal reticulation medially and irregular reticulation laterally, with 3 pairs of setae but with an additional seta on right side, placoid sensilla closer to hind pair of setae than to mid pair; mesopostphragma, measured from apex of mesoscutellum, 1.25 × as long as mesoscutellum. Fore wing 2.48 × as long as maximum width of wing disc; marginal fringe short, 0.08 × as long as maximum width of wing disc; submarginal vein shorter than marginal vein, with 11 setae; marginal vein with about 15 setae along anterior margin; postmarginal vein present but short, 0.29 × as long as stigmal vein; wing disc densely setose with relatively broad asetose area posterobasally. Metasoma. Metasoma about 1.18 × as long as mesosoma; tergites 1–7 with setae as follows: T1, 2+ 3; T2, 4+ 4; T3, 5+ 5; T4, 6+ 5; T5, 5+ 5; T6, 6 between cercal plates; T7, 16 in three rows; ovipositor basally located at base of T 3, slightly projecting beyond apex of metasoma, 1.69 × as long as mid tibia, third valvula 1.93 × as long as mid basitarsus. Male. Unknown. Host. An unidentified Diaspididae (Hemiptera) scale in the leaf sheath of bamboo (Figs 57–58). Distribution. China (Guangxi). Etymology. The new species name is derived from the Latin, leptocerus = slender horn. Diagnosis. Coccobius leptocerus is close to C. odonaspidis (Tachikawa 1964), which was collected from the white bamboo scale Odonaspis secreta Cockerell on bamboo in Japan, but can be distinguished from the latter by the following: body colour yellow to brownish yellow, except metasoma with T 1 –T 4 laterally and T 5 mostly brown to dark brown; antennal radicle and base of F 1 dark brown; scape, pedicel, remainder of F 1, F 2 pale yellow; F 3 and clava pale yellow to brownish yellow; mandible with three distinct, pointed teeth; and F 1 subequal in length to (1.06 × as long as) F 2, and F 2 longer than F 3. In C. odonaspidis the head and mesosoma are shining black, the metasoma is pale yellow with sharply defined black bands on either side from the base to the spiracles; the antennal radicle, scape and clava are black (lighter towards the tips), F 1 is black, and the remainder of the antennae is pale yellowish white; the mandible has two teeth and a truncation; and F 1 is distinctly longer than F 2 and F 2 is subequal in length to F 3. In the key to Chinese species given by Wang et al. (2014), C. leptocerus keys to couplet 5, but can be readily distinguished from all other Chinese species by the following: the mandible with three distinct, pointed teeth; antennal funicle segments being distinctly longer and slender, especially F 1 and F 2, as well as the different body colour and different antennal colour pattern.Published as part of Wang, Zhu-Hong, Huang, Jian & Polaszek, Andrew, 2014, Three new species of Coccobius Ratzeburg (Hymenoptera, Aphelinidae) and redescription of C. abdominis Huang and C. furviflagellatus Huang from China, pp. 460-472 in Zootaxa 3774 (5) on pages 469-471, DOI: 10.11646/zootaxa.3774.5.4, http://zenodo.org/record/22456
Microwave-aided transport measurements on high-density two-dimensional electron systems confined at AlGaN/GaN heterointerfaces
No full textFluorescence-based methods to study rapid dynamics and conformational flexibility in peptides
Get PDFIntramolecular collision of polypeptides is the primary step in protein folding, the
dynamics of which is of importance for understanding this fascinating topic. In this thesis
the rapid dynamics and flexibility of several sets of peptides were experimentally
investigated with a fluorescence-based method, where the long-lived, hydrophilic
fluorophore, 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO), was employed, which can be
selectively and efficiently quenched by tryptophan (Trp) through contact. An asparagine
derivative, Fmoc-DBO, was synthesized and applied to standard solid-phase peptide
synthesis to obtain DBO/Trp-labeled peptides. The end-to-end collision rates can then be
directly related to the intramolecular quenching of DBO by Trp. [Hudgins, R. R.; Huang,
F.; Gramlich, G.; Nau, W. M. J. Am. Chem. Soc. 2002, 124, 556-564 (Appendix I); Nau,
W. M.; Huang, F.; Wang, X.; Bakirci, H.; Gramlich, G.; Marquez, C. Chimia 2003, 57,
161-167 (Appendix III); Marquez, C.; Huang, F.; Nau, W. M. IEEE Trans. Nanobiosci.
2004, 3, 39-45 (Appendix V)]
This method has been further improved by establishing a dual quencher system, i.e.,
tyrosine (Tyr) was employed as an additional quencher, which can react with DBO upon
contact but with a lower efficiency than Trp. The combination of two probe/quencher
pairs with different quenching efficiency as well as the theoretical results for
intermolecular diffusion allows the extrapolation of the microscopic rate constants for
formation and dissociation of the end-to-end encounter complex even in the absence of
diffusion-controlled quenching. [Nau, W. M.; Huang, F.; Wang, X.; Bakirci, H.;
Gramlich, G.; Marquez, C. Chimia 2003, 57, 161-167 (Appendix III); Huang, F.; Hudgins,
R. R.; Nau, W. M. 2004, Submitted for publication (Appendix VI)]
We first applied this fluorescence-based method to measure the end-to-end collision
rate constants in flexible Gly-Ser peptides with varying length. The results suggest that the
behavior of real peptides deviates significantly from that of the ideal chain model and the
speed limit for protein folding should be faster than that reported previously. [Hudgins, R.
R.; Huang, F.; Gramlich, G.; Nau, W. M. J. Am. Chem. Soc. 2002, 124, 556-564
(Appendix I)]
We also investigated the end-to-end collision rates of another series of peptides
composed of different types of amino acids in the backbone but with identical length. The
experimental results have led to a conformational flexibility scale for amino acids in peptides and suggested that the flexibility of peptides is mainly determined by the atoms
and groups in close proximity to the backbone, while the more remote atoms and groups
have a smaller effect on the peptide dynamics due to their larger conformational space.
[Huang, F.; Nau, W. M. Angew. Chem. Int. Ed. 2003, 42, 2269-2272 (Appendix II);
Huang, F.; Nau, W. M. Res. Chem. Intermed. 2004, submitted for publication (Appendix
VII)]
Further investigations on peptides derived from the N-terminal b-hairpin of
ubiquitin were also carried out. The end-to-end collision rates in these peptides showed
significant dependence on the secondary structure, i.e., the turn segment is much more
flexible than the strand segments, which supports a previous proposal that the b-turn is the
initiator for the formation of the whole b-hairpin. Activation energies for end-to-end
collision of these peptides showed a good agreement with the collision rate constants,
which indicates that the activation energy may also be a measure of the flexibility of
peptides although it is not as sensitive as the collision rate. [Huang, F.; Hudgins, R. R.;
Nau, W. M. 2004, Submitted for publication (Appendix VI)]
Additionally, to get more detailed structural information of our peptides and to
reveal the underlying reasons for the deviation of the experimental length dependence of
end-to-end collision rates from the theoretical prediction, intramolecular fluorescence
resonance energy transfer (FRET) was applied as an independent approach to investigate
the dynamics in peptide chains. Two energy donor/acceptor pairs with small Förster
critical radius, where either naphthalene or Trp serves as energy donor and DBO as energy
acceptor, were employed. Energy transfer between naphthalene and DBO was first
investigated at a very short distance, where DBO and naphthalene were separated by
dimethylsiloxy. It was found that the Dexter mechanism might dominate in this system
due to the close proximity of donor and acceptor, the high flexibility of the tether, and the
nonviscous solvent employed. [Pischel, U.; Huang, F.; Nau, W. M. Photochem. Photobiol.
Sci. 2004, 3, 305-310 (Appendix IV)] However, when naphthalene and DBO were
covalently attached to the opposite ends of peptides and studied in water, control
experiments in the presence of cucurbit[7]uril as an encapsulating host suggested that
FRET was the dominant mechanism, which allowed us to apply the FRET technique to
recover the intramolecular end-to-end distance distribution and diffusion coefficient by
means of global analysis. In the investigation with naphthalene/DBO energy donor/acceptor pair, slower diffusion coefficients in shorter chains were found for the
series of flexible Gly-Ser peptides, suggesting that shorter chains may exhibit a larger
internal friction limiting the conformational change. Additionally, the intramolecular
energy transfer efficiency have been measured with the Trp/DBO pair and the effective
average end-to-end distances were calculated, which provided a lower limit for the mean
end-to-end distance of peptides for the global data analysis and offered a complementary
approach to interpret the end-to-end collision rates determined with the same pair but
based on a collision-induced quenching mechanism. [Huang, F.; Wang, X.; Haas, E.; Nau,
W. M. 2004, In preparation (Appendix VIII)]
The fluorescence-based method based on contact quenching mechanism has some
other potential applications. It has potential to be applied for high-throughput screening of
protease activity and to investigate the helix-coil transition in peptides
Effective expression of the Lee-Huang-Yang energy functional for heteronuclear mixtures
Get PDFWe consider a homogeneous heteronuclear Bose mixture with contact interactions at the mean-field collapse, i.e., with interspecies attraction equal to the mean geometrical intraspecies repulsion. We show that the Lee-Huang-Yang (LHY) energy functional is accurately approximated by an expression that has the same functional form as in the homonuclear case. The approximated energy functional is characterized by two exponents, which can be treated as fitting parameters. We demonstrate that the values of these parameters which preserve the invariance under permutation of the two atomic species are exactly those of the homonuclear case. Deviations from the exact expression of the LHY energy functional are discussed quantitatively and a specific application is described
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