Sample records for length tail length
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Poly A tail length analysis of in vitro transcribed mRNA by LC-MS.
Beverly, Michael; Hagen, Caitlin; Slack, Olga
2018-02-01
The 3'-polyadenosine (poly A) tail of in vitro transcribed (IVT) mRNA was studied using liquid chromatography coupled to mass spectrometry (LC-MS). Poly A tails were cleaved from the mRNA using ribonuclease T1 followed by isolation with dT magnetic beads. Extracted tails were then analyzed by LC-MS which provided tail length information at single-nucleotide resolution. A 2100-nt mRNA with plasmid-encoded poly A tail lengths of either 27, 64, 100, or 117 nucleotides was used for these studies as enzymatically added poly A tails showed significant length heterogeneity. The number of As observed in the tails closely matched Sanger sequencing results of the DNA template, and even minor plasmid populations with sequence variations were detected. When the plasmid sequence contained a discreet number of poly As in the tail, analysis revealed a distribution that included tails longer than the encoded tail lengths. These observations were consistent with transcriptional slippage of T7 RNAP taking place within a poly A sequence. The type of RNAP did not alter the observed tail distribution, and comparison of T3, T7, and SP6 showed all three RNAPs produced equivalent tail length distributions. The addition of a sequence at the 3' end of the poly A tail did, however, produce narrower tail length distributions which supports a previously described model of slippage where the 3' end can be locked in place by having a G or C after the poly nucleotide region. Graphical abstract Determination of mRNA poly A tail length using magnetic beads and LC-MS.
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NASA Technical Reports Server (NTRS)
Queijo, M J; Wolhart, Walter D
1951-01-01
An investigation was made to determine the effects of vertical-tail size and length and of fuselage shape and length on the static lateral stability characteristics of a model with wing and vertical tails having the quarter-chord lines swept back 45 degrees. The results indicate that the directional instability of the various isolated fuselages was about two-thirds as large as that predicted by classical theory.
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Sillanpää, Saila; Salminen, Juha-Pekka; Eeva, Tapio
2010-07-15
Stress during development may cause fluctuating asymmetry (FA), i.e. non-directional and random deviations from perfect symmetry in otherwise symmetrical morphological traits. These deviations affect the phenotypic quality of an individual. We manipulated the diet of nestling great tits, Parus major, to investigate how food quality and quantity affect FA in the length and mass of the outermost tail feathers of great tit nestlings in a polluted and an unpolluted area. High carotenoid diet groups and the control group had higher FA in tail feather length compared to a mealworm-supplemented (low carotenoid) group. This suggests that high carotenoid content in the diet may either directly or indirectly induce higher FA in tail feather length. Calcium is an essential element for birds and important component of feathers. The less calcium there was in the diet, the higher was the FA in tail feather length, which suggests that calcium availability may be an important determinant of the developmental stability of tail feather length. In the control group, in which nestlings were fully dependent upon natural food resources provided by their parents, FA in feather mass was higher in polluted than in unpolluted sites. Diet quality and quantity seemed to differentially affect FA in tail feather length and mass between the polluted and the unpolluted areas. FA in tail feather length in the control group was unaltered by pollution, while FA in tail feather mass was lower in the control group in the unpolluted than in the polluted area. Our study also demonstrates for the first time that the developmental stability of tail feather length and mass are affected by different factors. Copyright 2010 Elsevier B.V. All rights reserved.
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Polyadenylation state microarray (PASTA) analysis.
Beilharz, Traude H; Preiss, Thomas
2011-01-01
Nearly all eukaryotic mRNAs terminate in a poly(A) tail that serves important roles in mRNA utilization. In the cytoplasm, the poly(A) tail promotes both mRNA stability and translation, and these functions are frequently regulated through changes in tail length. To identify the scope of poly(A) tail length control in a transcriptome, we developed the polyadenylation state microarray (PASTA) method. It involves the purification of mRNA based on poly(A) tail length using thermal elution from poly(U) sepharose, followed by microarray analysis of the resulting fractions. In this chapter we detail our PASTA approach and describe some methods for bulk and mRNA-specific poly(A) tail length measurements of use to monitor the procedure and independently verify the microarray data.
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Adsorption of finite semiflexible polymers and their loop and tail distributions
NASA Astrophysics Data System (ADS)
Kampmann, Tobias A.; Kierfeld, Jan
2017-07-01
We discuss the adsorption of semiflexible polymers to a planar attractive wall and focus on the questions of the adsorption threshold for polymers of finite length and their loop and tail distributions using both Monte Carlo simulations and analytical arguments. For the adsorption threshold, we find three regimes: (i) a flexible or Gaussian regime if the persistence length is smaller than the adsorption potential range, (ii) a semiflexible regime if the persistence length is larger than the potential range, and (iii) for finite polymers, a novel crossover to a rigid rod regime if the deflection length exceeds the contour length. In the flexible and semiflexible regimes, finite size corrections arise because the correlation length exceeds the contour length. In the rigid rod regime, however, it is essential how the global orientational or translational degrees of freedom are restricted by grafting or confinement. We discuss finite size corrections for polymers grafted to the adsorbing surface and for polymers confined by a second (parallel) hard wall. Based on these results, we obtain a method to analyze adsorption data for finite semiflexible polymers such as filamentous actin. For the loop and tail distributions, we find power laws with an exponential decay on length scales exceeding the correlation length. We derive and confirm the loop and tail power law exponents for flexible and semiflexible polymers. This allows us to explain that, close to the transition, semiflexible polymers have significantly smaller loops and both flexible and semiflexible polymers desorb by expanding their tail length. The tail distribution allows us to extract the free energy per length of adsorption for actin filaments from experimental data [D. Welch et al., Soft Matter 11, 7507 (2015)].
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Russo, Gabrielle A
2016-01-01
This study evaluated the relationship between the morphology of the sacrum-the sole bony link between the tail or coccyx and the rest of the body-and tail length (including presence/absence) and function using a comparative sample of extant mammals spanning six orders (Primates, Carnivora, Rodentia, Diprotodontia, Pilosa, Scandentia; N = 472). Phylogenetically-informed regression methods were used to assess how tail length varied with respect to 11 external and internal (i.e., trabecular) bony sacral variables with known or suspected biomechanical significance across all mammals, only primates, and only non-primates. Sacral variables were also evaluated for primates assigned to tail categories ('tailless,' 'nonprehensile short-tailed,' 'nonprehensile long-tailed,' and 'prehensile-tailed'). Compared to primates with reduced tail lengths, primates with longer tails generally exhibited sacra having larger caudal neural openings than cranial neural openings, and last sacral vertebrae with more mediolaterally-expanded caudal articular surfaces than cranial articular surfaces, more laterally-expanded transverse processes, more dorsally-projecting spinous processes, and larger caudal articular surface areas. Observations were corroborated by the comparative sample, which showed that shorter-tailed (e.g., Lynx rufus [bobcat]) and longer-tailed (e.g., Acinonyx jubatus [cheetah]) non-primate mammals morphologically converge with shorter-tailed (e.g., Macaca nemestrina) and longer-tailed (e.g., Macaca fascicularis) primates, respectively. 'Prehensile-tailed' primates exhibited last sacral vertebrae with more laterally-expanded transverse processes and greater caudal articular surface areas than 'nonprehensile long-tailed' primates. Internal sacral variables performed poorly compared to external sacral variables in analyses of extant primates, and were thus deemed less useful for making inferences concerning tail length and function in extinct primates. The tails lengths of five extinct primates were reconstructed from the external sacral variables: Archaeolemur edwardsi had a 'nonprehensile long tail,' Megaladapis grandidieri, Palaeopropithecus kelyus, and Epipliopithecus vindobonensis probably had 'nonprehensile short tails,' and Proconsul heseloni was 'tailless.' Copyright © 2015 Elsevier Ltd. All rights reserved.
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Telling tails: selective pressures acting on investment in lizard tails.
Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W
2013-01-01
Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P < 0.001; also significant for five of the six families tested separately), as do longer (all species, P < 0.001; Iguanidae, P < 0.05; Lacertidae, P < 0.001; Scindidae, P < 0.001), climbing (all species, P < 0.05), and diurnal (all species, P < 0.01; Pygopodidae, P < 0.01) species; geckos without specialized tails (P < 0.05); or active-foraging skinks (P < 0.05). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., P < 0.01; Scindidae, P < 0.05), larger skinks (P < 0.05), climbing geckos (P < 0.05), or active-foraging iguanids (P < 0.05). The selective advantage of investing in a relatively longer tail may be due to locomotor mechanics, although the patterns observed are also largely consistent with predictions based on predation pressure.
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NASA Astrophysics Data System (ADS)
Zhang, Yunlong; Wu, Qiaowan; Hu, Weihua; Wang, Fan; Shao, Weihan; Zhang, Chengming; Zhao, Zhongbo; He, Hui; Fan, Qixue; Gu, Zemao
2016-07-01
The length-weight relationship and allometric growth patterns of hatchery-reared Chinese loach, Paramisgurnus dabryanus (Dabry de Thiersant, 1872), were determined from hatching to 60 days after hatching. A best power model was estimated for the length-weight relationship during the early life stages. Positive allometric growth for the head segment, trunk length, tail length and eye diameter was also found in the early life stages, while body depth, tail depth, tail fin length, pectoral fin length and barbel length displayed a negative coefficient. During the subsequent early developmental stage, the growth coefficients showed a clear and common tendency towards isometry for all measured body ratios. The allometric growth changes in Chinese loach during the early stage are possibly the result of selective organogenesis directed towards survival priorities.
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Postsacral vertebral morphology in relation to tail length among primates and other mammals.
Russo, Gabrielle A
2015-02-01
Tail reduction/loss independently evolved in a number of mammalian lineages, including hominoid primates. One prerequisite to appropriately contextualizing its occurrence and understanding its significance is the ability to track evolutionary changes in tail length throughout the fossil record. However, to date, the bony correlates of tail length variation among living taxa have not been comprehensively examined. This study quantifies postsacral vertebral morphology among living primates and other mammals known to differ in relative tail length (RTL). Linear and angular measurements with known biomechanical significance were collected on the first, mid-, and transition proximal postsacral vertebrae, and their relationship with RTL was assessed using phylogenetic generalized least-squares regression methods. Compared to shorter-tailed primates, longer-tailed primates possess a greater number of postsacral vertebral features associated with increased proximal tail flexibility (e.g., craniocaudally longer vertebral bodies), increased intervertebral body joint range of motion (e.g., more circularly shaped cranial articular surfaces), and increased leverage of tail musculature (e.g., longer spinous processes). These observations are corroborated by the comparative mammalian sample, which shows that distantly related short-tailed (e.g., Phascolarctos, Lynx) and long-tailed (e.g., Dendrolagus, Acinonyx) nonprimate mammals morphologically converge with short-tailed (e.g., Macaca tonkeana) and long-tailed (e.g., Macaca fascicularis) primates, respectively. Multivariate models demonstrate that the variables examined account for 70% (all mammals) to 94% (only primates) of the variance in RTL. Results of this study may be used to infer the tail lengths of extinct primates and other mammals, thereby improving our understanding about the evolution of tail reduction/loss. © 2014 Wiley Periodicals, Inc.
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Karbalay-Doust, S; Noorafshan, A
2011-01-01
Metronidazole (MTZ) is used as an antiparasitic drug. Curcumin is considered as anti-oxidant and anti-inflammatory agent. The ameliorative effects of curcumin on MTZ induced toxicity on mice spermatozoon tail length, count, motility and testosterone level were investigated. MTZ was administered in 500 and 165 (high and therapeutic doses) mg/kg/day, with and without curcumin (100 mg/kg/day). After 16 days the above parameters were assessed. Spermatozoon count and motility and serum testosterone level MTZ-treated (500 and 165) mice were reduced. In the mice treated with MTZ+curcumin these parameters decreased but in a lesser extent than the MTZ-treated animals. Mid-piece and total lengths of the spermatozoon tail in control animals were 31.6 ± 9.0 μm and 100.3 ± 15.0 μm and in the mice treated with high doses (500) of MTZ were reduced. The mid-piece and total spermatozoon tail length has been decreased in a lesser extent in the mice treated with high dose MTZ+curcumin than the mice treated with high dose MTZ (p<0.01). But the length was not changed in animals treated with therapeutic dose of MTZ. It means curcumin treated animals had ~52% and ~39% average increase in mid-piece and total lengths in comparison with the MTZ-treated (500) animals. Stereological estimation of the sperm tail length, including sampling of spermatozoa and also counting of the intersections of their tails with the stereological grids was a rapid technique and took only 5-10 minutes. It can be concluded that curcumin has an ameliorative effect on the spermatozoon, testosterone level and tail length in MTZ-treated mice.
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Hafezi, Mohammad-Javad; Sharif, Farhad
2015-11-01
Study on the effect of amphiphilic copolymers structure on their self assembly is an interesting subject, with important applications in the area of drug delivery and biological system treatments. Brownian dynamics simulations were performed to study self-assembly of the linear amphiphilic block copolymers with the same hydrophilic head, but hydrophobic tails of different lengths. Critical micelle concentration (CMC), gyration radius distribution, micelle size distribution, density profiles of micelles, shape anisotropy, and dynamics of micellization were investigated as a function of tail length. Simulation results were compared with predictions from theory and simulation for mixed systems of block copolymers with long and short hydrophobic tail, reported in our previous work. Interestingly, the equilibrium structural and dynamic parameters of pure and mixed block copolymers were similarly dependant on the intrinsic/apparent hydrophobic block length. Log (CMC) was, however; proportional to the tail length and had a different behavior compared to the mixed system. The power law scaling relation of equilibrium structural parameters for amphiphilic block copolymers predicts the same dependence for similar hydrophobic tail lengths, but the power law prediction of CMC is different, which is due to its simplifying assumptions as discussed here. Copyright © 2015 Elsevier Inc. All rights reserved.
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Effect of nose shape and tail length on supersonic stability characteristics of a projectile
NASA Technical Reports Server (NTRS)
Sawyer, W. C.; Collins, I. K.
1973-01-01
The effect of nose shape and tail length on the static stability of a fin-stabilized projectile has been investigated in the Langley Unitary Plan with tunnel at angles of attack to about 12 deg for a Mach number range from 1.5 to 2.5. The tests were made at a constant Reynolds number of 6.56 x 1,000,000 per meter. The results of the investigation showed that nose shape had no effect on the static stability. Increasing the tail length resulted in a progressively stabilizing tendency. However, only the 1.5-caliber-tail-length configuration was stable over the test angle-of-attack range at Mach number 1.5. This configuration was marginally stable or unstable at the higher Mach numbers, and the shorter configurations were unstable at all Mach numbers for either part of or the entire test angle-of-attack range.
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Chronic occupational exposure to hexavalent chromium causes DNA damage in electroplating workers.
Zhang, Xu-Hui; Zhang, Xuan; Wang, Xu-Chu; Jin, Li-Fen; Yang, Zhang-Ping; Jiang, Cai-Xia; Chen, Qing; Ren, Xiao-Bin; Cao, Jian-Zhong; Wang, Qiang; Zhu, Yi-Min
2011-04-12
Occupational exposure to chromium compounds may result in adverse health effects. This study aims to investigate whether low-level hexavalent chromium (Cr(VI)) exposure can cause DNA damage in electroplating workers. 157 electroplating workers and 93 control subjects with no history of occupational exposure to chromium were recruited in Hangzhou, China. Chromium levels in erythrocytes were determined by graphite furnace atomic absorption spectrophotometer. DNA damage in peripheral lymphocytes was evaluated with the alkaline comet assay by three parameters: Olive tail moment, tail length and percent of DNA in the comet tail (tail DNA%). Urinary 8-OHdG levels were measured by ELISA. Chromium concentration in erythrocytes was about two times higher in electroplating workers (median: 4.41 μg/L) than that in control subjects (1.54 μg/L, P < 0.001). The medians (range) of Olive tail moment, tail length and tail DNA% in exposed workers were 1.13 (0.14-6.77), 11.17 (3.46-52.19) and 3.69 (0.65-16.20), and were significantly higher than those in control subjects (0.14 (0.01-0.39), 3.26 (3.00-4.00) and 0.69 (0.04-2.74), P < 0.001). Urinary 8-OHdG concentration was 13.65 (3.08-66.30) μg/g creatinine in exposed workers and 8.31 (2.94-30.83) μg/g creatinine in control subjects (P < 0.001). The differences of urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA% between these two groups remained significant (P < 0.001) even after stratification by potential confounding factors such as age, gender, and smoking status. Chromium exposure was found to be positively associated with chromium levels in erythrocytes, urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA%. Positive dose-response associations were also found between chromium levels in erythrocytes and Olive tail moment, tail length and tail DNA%. The findings in this study indicated that there was detectable chromium exposure in electroplating workers. Low-level occupational chromium exposure induced DNA damage.
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Chronic occupational exposure to hexavalent chromium causes DNA damage in electroplating workers
2011-01-01
Background Occupational exposure to chromium compounds may result in adverse health effects. This study aims to investigate whether low-level hexavalent chromium (Cr(VI)) exposure can cause DNA damage in electroplating workers. Methods 157 electroplating workers and 93 control subjects with no history of occupational exposure to chromium were recruited in Hangzhou, China. Chromium levels in erythrocytes were determined by graphite furnace atomic absorption spectrophotometer. DNA damage in peripheral lymphocytes was evaluated with the alkaline comet assay by three parameters: Olive tail moment, tail length and percent of DNA in the comet tail (tail DNA%). Urinary 8-OHdG levels were measured by ELISA. Results Chromium concentration in erythrocytes was about two times higher in electroplating workers (median: 4.41 μg/L) than that in control subjects (1.54 μg/L, P < 0.001). The medians (range) of Olive tail moment, tail length and tail DNA% in exposed workers were 1.13 (0.14-6.77), 11.17 (3.46-52.19) and 3.69 (0.65-16.20), and were significantly higher than those in control subjects (0.14 (0.01-0.39), 3.26 (3.00-4.00) and 0.69 (0.04-2.74), P < 0.001). Urinary 8-OHdG concentration was 13.65 (3.08-66.30) μg/g creatinine in exposed workers and 8.31 (2.94-30.83) μg/g creatinine in control subjects (P < 0.001). The differences of urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA% between these two groups remained significant (P < 0.001) even after stratification by potential confounding factors such as age, gender, and smoking status. Chromium exposure was found to be positively associated with chromium levels in erythrocytes, urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA%. Positive dose-response associations were also found between chromium levels in erythrocytes and Olive tail moment, tail length and tail DNA%. Conclusion The findings in this study indicated that there was detectable chromium exposure in electroplating workers. Low-level occupational chromium exposure induced DNA damage. PMID:21481275
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Zhou, Dan; Niu, Jiqiang
2017-01-01
Trains with different numbers of cars running in the open air were simulated using the delayed detached-eddy simulation (DDES). The numbers of cars included in the simulation are 3, 4, 5 and 8. The aim of this study was to investigate how train length influences the boundary layer, the wake flow, the surface pressure, the aerodynamic drag and the friction drag. To certify the accuracy of the mesh and methods, the drag coefficients from numerical simulation of trains with 3 cars were compared with those from the wind tunnel test, and agreement was obtained. The results show that the boundary layer is thicker and the wake vortices are less symmetric as the train length increases. As a result, train length greatly affects pressure. The upper surface pressure of the tail car reduced by 2.9%, the side surface pressure of the tail car reduced by 8.3% and the underneath surface pressure of the tail car reduced by 19.7% in trains that included 3 cars to those including 8 cars. In addition, train length also has a significant effect on the friction drag coefficient and the drag coefficient. The friction drag coefficient of each car in a configuration decreases along the length of the train. In a comparison between trains consisting of 3 cars to those consisting of 8 cars, the friction drag coefficient of the tail car reduced by 8.6% and the drag coefficient of the tail car reduced by 3.7%. PMID:29261758
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Large momentum part of a strongly correlated Fermi gas
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tan, Shina
2008-12-15
It is well known that the momentum distribution of the two-component Fermi gas with large scattering length has a tail proportional to 1/k{sup 4} at large k. We show that the magnitude of this tail is equal to the adiabatic derivative of the energy with respect to the reciprocal of the scattering length, multiplied by a simple constant. This result holds at any temperature (as long as the effective interaction radius is negligible) and any large scattering length; it also applies to few-body cases. We then show some more connections between the 1/k{sup 4} tail and various physical quantities, includingmore » the pressure at thermal equilibrium and the rate of change of energy in a dynamic sweep of the inverse scattering length.« less
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Katoch, Parul; Mitra, Shalini; Ray, Anuttoma; Kelsey, Linda; Roberts, Brett J.; Wahl, James K.; Johnson, Keith R.; Mehta, Parmender P.
2015-01-01
Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size. PMID:25548281
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Empirical scaling of the length of the longest increasing subsequences of random walks
NASA Astrophysics Data System (ADS)
Mendonça, J. Ricardo G.
2017-02-01
We provide Monte Carlo estimates of the scaling of the length L n of the longest increasing subsequences of n-step random walks for several different distributions of step lengths, short and heavy-tailed. Our simulations indicate that, barring possible logarithmic corrections, {{L}n}∼ {{n}θ} with the leading scaling exponent 0.60≲ θ ≲ 0.69 for the heavy-tailed distributions of step lengths examined, with values increasing as the distribution becomes more heavy-tailed, and θ ≃ 0.57 for distributions of finite variance, irrespective of the particular distribution. The results are consistent with existing rigorous bounds for θ, although in a somewhat surprising manner. For random walks with step lengths of finite variance, we conjecture that the correct asymptotic behavior of L n is given by \\sqrt{n}\\ln n , and also propose the form for the subleading asymptotics. The distribution of L n was found to follow a simple scaling form with scaling functions that vary with θ. Accordingly, when the step lengths are of finite variance they seem to be universal. The nature of this scaling remains unclear, since we lack a working model, microscopic or hydrodynamic, for the behavior of the length of the longest increasing subsequences of random walks.
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Sumi, Hajime; Itoh, Akihiro; Kawashima, Hiroki; Ohno, Eizaburo; Itoh, Yuya; Nakamura, Yosuke; Hiramatsu, Takeshi; Sugimoto, Hiroyuki; Hayashi, Daijuro; Kuwahara, Takamichi; Morishima, Tomomasa; Kawai, Manabu; Furukawa, Kazuhiro; Funasaka, Kohei; Nakamura, Masanao; Miyahara, Ryoji; Katano, Yoshiaki; Ishigami, Masatoshi; Ohmiya, Naoki; Goto, Hidemi; Hirooka, Yoshiki
2014-08-01
Transabdominal ultrasonography (US) is commonly used for the initial screening of bilio-pancreatic diseases in Asian countries due to its widespread availability, the non-invasiveness and the cost-effectiveness. However, it is considered that US has limits to observe the area, namely the blind area. The observation of the pancreatic tail is particularly difficult. The goal of this study was to examine the pancreatic tail region that cannot be visualized on transverse scanning of the upper abdomen using US with spatial positional information and factors related to visualization, and observation of the tail from the splenic hilum. Thirty-nine patients with pancreatic/biliary tract disease underwent CT and US with GPS-like technology and fusion imaging for measurement of the real pancreatic length and the predicted/real unobservable (PU and RU) length of the pancreatic tail. RU from US on transverse scanning and the real pancreatic length were used to determine the unobservable area (UA: RU/the real pancreatic length). Relationships of RU with physical and hematological variables that might influence visualization of the pancreatic tail were investigated. The real pancreatic length was 160.9 ± 16.4mm, RU was 41.0 ± 17.8mm, and UA was 25.3 ± 10.4%. RU was correlated with BMI (R=0.446, P=0.004) and waist circumferences (R=0.354, P=0.027), and strongly correlated with PU (R=0.788, P<0.001). The pancreatic tail was visible from the splenic hilum in 22 (56%) subjects and was completely identified in 13 (33%) subjects. Combined GPS-like technology with fusion imaging was useful for the objective estimation of the pancreatic blind area. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
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Aqueous Foam Stabilized by Tricationic Amphiphilic Surfactants
NASA Astrophysics Data System (ADS)
Heerschap, Seth; Marafino, John; McKenna, Kristin; Caran, Kevin; Feitosa, Klebert; Kevin Caran's Research Group Collaboration
2015-03-01
The unique surface properties of amphiphilic molecules have made them widely used in applications where foaming, emulsifying or coating processes are needed. The development of novel architectures with multi-cephalic/tailed molecules have enhanced their anti-bacterial activity in connection with tail length and the nature of the head group. Here we report on the foamability of two triple head double, tail cationic surfactants (M-1,14,14, M-P, 14,14) and a triple head single tail cationic surfactant (M-1,1,14) and compare them with commercially available single headed, single tailed anionic and cationic surfactants (SDS,CTAB and DTAB). The results show that bubble rupture rate decrease with the length of the carbon chain irrespective of head structure. The growth rate of bubbles with short tailed surfactants (SDS) and longer, single tailed tricationic surfactants (M-1,1,14) was shown to be twice as high as those with longer tailed surfactants (CTAB, M-P,14,14, M-1,14,14). This fact was related to the size variation of bubbles, where the foams made with short tail surfactants exhibited higher polydispersivity than those with short tails. This suggests that foams with tricationic amphiphilics are closed linked to their tail length and generally insensitive to their head structure.
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Kuraishi, T; Sun, Y; Aoki, F; Imakawa, K; Sakai, S
2000-01-01
The length of casein mRNA from the lactating mouse mammary gland, as assessed on Northern blots, is shorter after weaning, but is elongated following the removal of milk. In order to investigate this phenomenon, the molecular structures of beta- and gamma-casein mRNAs were analysed. The coding and non-coding regions of the two forms were the same length, but the long form of casein mRNA had a longer poly(A) tail than the short form (P<0.05). In order to examine the stability of casein mRNA under identical conditions, casein mRNAs with the long and short poly(A) tails were incubated in the rabbit reticulocyte lysate (RRL) cell-free translation system. Casein mRNA with the long poly(A) tail had a longer half-life than that with the short tail (P<0.05). The beta- and gamma-casein mRNAs were first degraded into 0.92 and 0.81 kb fragments respectively. With undegraded mRNA, the poly(A) tail shortening by exoribonuclease was not observed until the end of the incubation. Northern blot analysis showed that casein mRNA with the long poly(A) tail was protected efficiently from endoribonucleases. We conclude that the length of the poly(A) tail of casein mRNA in the lactating mammary gland changes depending upon the accumulation and removal of the gland's milk, and we show that the longer poly(A) tail potentially protects the mRNA from degradation by endoribonucleases. PMID:10749689
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Bauer, M; Breed, W G
2006-01-01
In Australia, there are around 60 species of murid rodents that occur in the subfamily Hydromyinae, most of which produce highly complex, monomorphic, spermatozoa in which the head has an apical hook together with two ventral processes containing filamentous actin and a long tail of species-specific length. One of the few exceptions to this is the spinifex hopping mouse, Notomys alexis, whose spermatozoa have previously been shown to have pleiomorphic heads. In this study, the structural organisation of the sperm head has been investigated in more detail and the variability in length of the midpiece and total length of the sperm tail has been determined for this species. The findings confirm that pleiomorphic sperm heads are invariably present in these animals and that this variability is associated with that of the nucleus, although nuclear vacuoles were not evident. The total length of the sperm tail, as well as that of the midpiece, was also highly variable both within, as well as between, individual animals. The reason(s) for this high degree of variability in sperm morphology is not known but it may relate to a relaxation of the genetic control of sperm form owing to depressed levels of inter-male sperm competition.
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Marafino, John N; Gallagher, Tara M; Barragan, Jhosdyn; Volkers, Brandi L; LaDow, Jade E; Bonifer, Kyle; Fitzgerald, Gabriel; Floyd, Jason L; McKenna, Kristin; Minahan, Nicholas T; Walsh, Brenna; Seifert, Kyle; Caran, Kevin L
2015-07-01
Two novel series of tris-cationic, tripled-headed, double-tailed amphiphiles were synthesized and the effects of tail length and head group composition on the critical aggregation concentration (CAC), thermodynamic parameters, and minimum inhibitory concentration (MIC) against six bacterial strains were investigated. Synergistic antibacterial combinations of these amphiphiles were also identified. Amphiphiles in this study are composed of a benzene core with three benzylic ammonium bromide groups, two of which have alkyl chains, each 8-16 carbons in length. The third head group is a trimethylammonium or pyridinium. Log of critical aggregation concentration (log[CAC]) and heat of aggregation (ΔHagg) were both inversely proportional to the length of the linear hydrocarbon chains. Antibacterial activity increases with tail length until an optimal tail length of 12 carbons per chain, above which, activity decreased. The derivatives with two 12 carbon chains had the best antibacterial activity, killing all tested strains at concentrations of 1-2μM for Gram-positive and 4-16μM for Gram-negative bacteria. The identity of the third head group (trimethylammonium or pyridinium) had minimal effect on colloidal and antibacterial activity. The antibacterial activity of several binary combinations of amphiphiles from this study was higher than activity of individual amphiphiles, indicating that these combinations are synergistic. These amphiphiles show promise as novel antibacterial agents that could be used in a variety of applications. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Description of Globodera ellingtonae n. sp. (Nematoda: Heteroderidae) from Oregon
Handoo, Zafar A.; Carta, Lynn K.; Skantar, Andrea M.; Chitwood, David J.
2012-01-01
A new species of cyst nematode, Globodera ellingtonae, is described from soil collected from a field in Oregon. Second-stage juveniles (J2) of the species are characterized by body length of 365-515 μm, stylet length of 19-22.5 μm, basal knobs rounded posteriorly and pointed anteriorly, tail 39-55 μm, hyaline tail terminus 20-32.5 μm, and tail tapering uniformly but abruptly narrowing and constricted near the posterior third of the hyaline portion, ending with a peg-like, finely rounded to pointed terminus. Cysts are spherical to sub-spherical, dark to light brown and circumfenestrate and cyst wall pattern is ridge-like with heavy punctations. Males have a stylet length of 21-25 μm and spicule length of 30-37 μm with a pointed thorn-like tip. Females have a stylet length of 20-22.5 μm, one head annule and labial disc, heavy punctations on the cuticle, and short vulval slit 7.5-8 μm long. Morphologically this new, round-cyst species differs from the related species G. pallida, G. rostochiensis, G. tabacum complex and G. mexicana by its distinctive J2 tail, and by one or another of the following: shorter mean stylet length in J2, females and males; number of refractive bodies in the hyaline tail terminus of J2; cyst morphology including Granek’s ratio; number of cuticular ridges between the anus and vulva; and in the shape and length of spicules in males. Its relationship to these closely related species are discussed. Based upon analysis of ribosomal internal transcribed spacer (ITS) sequences, G. ellingtonae n. sp. is distinct from G. pallida, G. rostochiensis, G. tabacum and G. mexicana. Bayesian and Maximum Parsimony analysis of cloned ITS rRNA gene sequences indicated three clades, with intraspecific variability as high as 2.8%. In silico analysis revealed ITS restriction fragment length polymorphisms for enzymes Bsh 1236I, Hinf I, and Rsa I that overlap patterns for other Globodera species. PMID:23483076
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Description of Globodera ellingtonae n. sp. (Nematoda: Heteroderidae) from Oregon.
Handoo, Zafar A; Carta, Lynn K; Skantar, Andrea M; Chitwood, David J
2012-03-01
A new species of cyst nematode, Globodera ellingtonae, is described from soil collected from a field in Oregon. Second-stage juveniles (J2) of the species are characterized by body length of 365-515 μm, stylet length of 19-22.5 μm, basal knobs rounded posteriorly and pointed anteriorly, tail 39-55 μm, hyaline tail terminus 20-32.5 μm, and tail tapering uniformly but abruptly narrowing and constricted near the posterior third of the hyaline portion, ending with a peg-like, finely rounded to pointed terminus. Cysts are spherical to sub-spherical, dark to light brown and circumfenestrate and cyst wall pattern is ridge-like with heavy punctations. Males have a stylet length of 21-25 μm and spicule length of 30-37 μm with a pointed thorn-like tip. Females have a stylet length of 20-22.5 μm, one head annule and labial disc, heavy punctations on the cuticle, and short vulval slit 7.5-8 μm long. Morphologically this new, round-cyst species differs from the related species G. pallida, G. rostochiensis, G. tabacum complex and G. mexicana by its distinctive J2 tail, and by one or another of the following: shorter mean stylet length in J2, females and males; number of refractive bodies in the hyaline tail terminus of J2; cyst morphology including Granek's ratio; number of cuticular ridges between the anus and vulva; and in the shape and length of spicules in males. Its relationship to these closely related species are discussed. Based upon analysis of ribosomal internal transcribed spacer (ITS) sequences, G. ellingtonae n. sp. is distinct from G. pallida, G. rostochiensis, G. tabacum and G. mexicana. Bayesian and Maximum Parsimony analysis of cloned ITS rRNA gene sequences indicated three clades, with intraspecific variability as high as 2.8%. In silico analysis revealed ITS restriction fragment length polymorphisms for enzymes Bsh 1236I, Hinf I, and Rsa I that overlap patterns for other Globodera species.
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Katoch, Parul; Mitra, Shalini; Ray, Anuttoma; Kelsey, Linda; Roberts, Brett J; Wahl, James K; Johnson, Keith R; Mehta, Parmender P
2015-02-20
Connexins, the constituent proteins of gap junctions, are transmembrane proteins. A connexin (Cx) traverses the membrane four times and has one intracellular and two extracellular loops with the amino and carboxyl termini facing the cytoplasm. The transmembrane and the extracellular loop domains are highly conserved among different Cxs, whereas the carboxyl termini, often called the cytoplasmic tails, are highly divergent. We have explored the role of the cytoplasmic tail of Cx32, a Cx expressed in polarized and differentiated cells, in regulating gap junction assembly. Our results demonstrate that compared with the full-length Cx32, the cytoplasmic tail-deleted Cx32 is assembled into small gap junctions in human pancreatic and prostatic cancer cells. Our results further document that the expression of the full-length Cx32 in cells, which express the tail-deleted Cx32, increases the size of gap junctions, whereas the expression of the tail-deleted Cx32 in cells, which express the full-length Cx32, has the opposite effect. Moreover, we show that the tail is required for the clustering of cell-cell channels and that in cells expressing the tail-deleted Cx32, the expression of cell surface-targeted cytoplasmic tail alone is sufficient to enhance the size of gap junctions. Our live-cell imaging data further demonstrate that gap junctions formed of the tail-deleted Cx32 are highly mobile compared with those formed of full-length Cx32. Our results suggest that the cytoplasmic tail of Cx32 is not required to initiate the assembly of gap junctions but for their subsequent growth and stability. Our findings suggest that the cytoplasmic tail of Cx32 may be involved in regulating the permeability of gap junctions by regulating their size. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
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Intermonolayer Friction and Surface Shear Viscosity of Lipid Bilayer Membranes
den Otter, W. K.; Shkulipa, S. A.
2007-01-01
The flow behavior of lipid bilayer membranes is characterized by a surface viscosity for in-plane shear deformations, and an intermonolayer friction coefficient for slip between the two leaflets of the bilayer. Both properties have been studied for a variety of coarse-grained double-tailed model lipids, using equilibrium and nonequilibrium molecular dynamics simulations. For lipids with two identical tails, the surface shear viscosity rises rapidly with tail length, while the intermonolayer friction coefficient is less sensitive to the tail length. Interdigitation of lipid tails across the bilayer midsurface, as observed for lipids with two distinct tails, strongly enhances the intermonolayer friction coefficient, but hardly affects the surface shear viscosity. The simulation results are compared against the available experimental data. PMID:17468168
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Verma, Deepak; Sankhyan, Varun; Katoch, Sanjeet; Thakur, Yash Pal
2015-12-01
In the present study, biometric traits (body length [BL], heart girth [HG], paunch girth (PG), forelimb length (FLL), hind limb length (HLL), face length, forehead width, forehead length, height at hump, hump length (HL), hook to hook distance, pin to pin distance, tail length (TL), TL up to switch, horn length, horn circumference, and ear length were studied in 218 adult hill cattle of Himachal Pradesh for phenotypic characterization. Morphological and biometrical observations were recorded on 218 hill cattle randomly selected from different districts within the breeding tract. Multivariate statistics and principal component analysis are used to account for the maximum portion of variation present in the original set of variables with a minimum number of composite variables through Statistical software, SAS 9.2. Five components were extracted which accounted for 65.9% of variance. The first component explained general body confirmation and explained 34.7% variation. It was represented by significant loading for BL, HG, PG, FLL, and HLL. Communality estimate ranged from 0.41 (HL) to 0.88 (TL). Second, third, fourth, and fifth component had a high loading for tail characteristics, horn characteristics, facial biometrics, and rear body, respectively. The result of component analysis of biometric traits suggested that indigenous hill cattle of Himachal Pradesh are small and compact size cattle with a medium hump, horizontally placed short ears, and a long tail. The study also revealed that factors extracted from the present investigation could be used in breeding programs with sufficient reduction in the number of biometric traits to be recorded to explain the body confirmation.
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Abolafia, J.; Peña-Santiago, R.
2003-01-01
A new species of the genus Nothacrobeles is described from natural areas (a salt lake) in the Southeast Iberian Peninsula. Nothacrobeles lanceolatus sp. n. is characterized by its body length, two rows of cuticular punctations per annulus, labial probolae bifurcate with divergent prongs, pharyngeal corpus 2.4 to 3.5 times isthmus length, spermatheca length, postuterine sac 0.5 to 1.1 times the corresponding body diameter ratio, female tail conical and bearing a spindle-shaped or conical mucro with acute terminus, phasmid at 8 to 17 µm posterior to the anus, male tail conical with acute mucro, spicules length, and gubernaculum length. In addition, Nothacrobeles cf. lunensis and Zeldia punctata are studied. Cervidellus capricornis is transferred to genus Nothacrobeles. A key to species of Nothacrobeles is also provided. PMID:19262756
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Vohra, V.; Niranjan, S. K.; Mishra, A. K.; Jamuna, V.; Chopra, A.; Sharma, Neelesh; Jeong, Dong Kee
2015-01-01
Phenotypic characterization and body biometric in 13 traits (height at withers, body length, chest girth, paunch girth, ear length, tail length, length of tail up to switch, face length, face width, horn length, circumference of horn at base, distances between pin bone and hip bone) were recorded in 233 adult Gojri buffaloes from Punjab and Himachal Pradesh states of India. Traits were analysed by using varimax rotated principal component analysis (PCA) with Kaiser Normalization to explain body conformation. PCA revealed four components which explained about 70.9% of the total variation. First component described the general body conformation and explained 31.5% of total variation. It was represented by significant positive high loading of height at wither, body length, heart girth, face length and face width. The communality ranged from 0.83 (hip bone distance) to 0.45 (horn length) and unique factors ranged from 0.16 to 0.55 for all these 13 different biometric traits. Present study suggests that first principal component can be used in the evaluation and comparison of body conformation in buffaloes and thus provides an opportunity to distinguish between early and late maturing to adult, based on a small group of biometric traits to explain body conformation in adult buffaloes. PMID:25656215
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Tse, C Y; Chan, K M; Wong, C K
2010-06-01
In Hong Kong, suspended solids (SS) introduced by dredging and mud disposal activities are a major cause of mass mortality in cage-cultured marine fish. We have used DNA damage in liver cells, as determined by the comet assay, to assess the impact of SS on the orange-spotted grouper Epinephelus coioides. Seabed sediments were collected from a heavily polluted site in Victoria Harbor and two less polluted sites in Port Shelter and Mirs Bay. Sediments from Victoria Harbor contained higher levels of copper (Cu) and polycyclic aromatic hydrocarbons (PAHs) than those from the other sites. In a 10-day experiment, SS from all three sites induced significant increase in comet tail length, but not in percentage (%) tail DNA. In a 20-day experiment, fish exposed to polluted SS from Victoria Harbor exhibited a significant increase in comet tail length after 5 days and % tail DNA after 10 days. After a 10-day recovery period, however, DNA damage was reduced as tail length and % tail DNA returned to control levels. These results suggest that DNA damage measured by the comet assay is a highly sensitive biomarker for assessing the genotoxic effects of SS to marine fish.
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Heepchantree, Worapa; Paratasilpin, Thipmani; Kangwanpong, Daoroong
2006-06-01
The comet assay was performed to evaluate the effect of environmental exposure between human populations residing in two areas that differ in lung cancer incidence, Saraphi (n = 91) and Chom Thong (n = 94). Three parameters, the tail length, tail intensity, and tail moment, were used to detect DNA damage in peripheral blood and stimulated lymphocytes with and without the DNA repair inhibitor, aphidicolin. Internal standards, cryopreserved isolated lymphocytes, and isolated lymphocytes irradiated with 2 Gy gamma rays, were used to correct the interexperimental variability. Results revealed a significant difference between two populations only when the tail length was used to measure DNA damage. The evaluation of various potential confounding factors, such as gender, pesticide exposure, smoking, alcohol drinking, and fermented tea leaf or betel nut chewing, indicated no significant influence in DNA damage. In conclusion, significant difference in DNA damage, detected only by tail length between the two populations residing in the areas with different incidence of lung cancer, may reflect a nonhazardous level of exposure to toxic substances.
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Survival and reproductive rate of mites in relation to resistance of their barn swallow hosts.
Møller, A P
2000-08-01
Parasite resistance may act via a number of different mechanisms that regulate or control the survival and the reproductive rate of parasites. Observations and experiments were used to test for effects of host resistance on parasite survival and rate of reproduction. Natural levels of infestation of barn swallow Hirundo rustica nests by the tropical fowl mite Ornithonyssus bursa were positively related to brood size, inversely related to the length of the outermost tail feathers of male nest owners (a secondary sexual character) and affected by time of reproduction by the host. A mite inoculation experiment, in which 50 adult mites were introduced into nests during the laying period of the host, was used to test for differential survival and reproduction of mites as a function of host resistance. The relationship between survival and reproduction of parasites, male tail length and host resistance was investigated. There was a negative relationship between mite numbers per nest after fledging of nestlings and male tail length. This relationship was mainly caused by a reduction in the number of mites in the first and second nymph stage with increasing tail length of male hosts, implying a reduction in rate of reproduction of mites. The proportion of mites that had recently fed was inversely related to tail length of male hosts. The proportion of nymph stages was positively related to the proportion of mites that had recently had a blood meal. Parasite resistance of barn swallows to the tropical fowl mite thus appeared to act through increased mortality rate of adult and nymph stages of mites, and through reduced reproductive rates of mites on resistant hosts. This is the first study demonstating a direct relationship between fitness components of a parasite and the expression of a secondary sexual character of a host.
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Correlation between length and tilt of lipid tails
NASA Astrophysics Data System (ADS)
Kopelevich, Dmitry I.; Nagle, John F.
2015-10-01
It is becoming recognized from simulations, and to a lesser extent from experiment, that the classical Helfrich-Canham membrane continuum mechanics model can be fruitfully enriched by the inclusion of molecular tilt, even in the fluid, chain disordered, biologically relevant phase of lipid bilayers. Enriched continuum theories then add a tilt modulus κθ to accompany the well recognized bending modulus κ. Different enrichment theories largely agree for many properties, but it has been noticed that there is considerable disagreement in one prediction; one theory postulates that the average length of the hydrocarbon chain tails increases strongly with increasing tilt and another predicts no increase. Our analysis of an all-atom simulation favors the latter theory, but it also shows that the overall tail length decreases slightly with increasing tilt. We show that this deviation from continuum theory can be reconciled by consideration of the average shape of the tails, which is a descriptor not obviously includable in continuum theory.
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Developmental origin of limb size variation in lizards.
Andrews, Robin M; Skewes, Sable A
2017-05-01
In many respects, reptile hatchlings are fully functional, albeit miniature, adults. This means that the adult morphology must emerge during embryonic development. This insight emphasizes the connection between the mechanisms that generate phenotypic variation during embryonic development and the action of selection on post-hatching individuals. To determine when species-specific differences in limb and tail lengths emerge during embryonic development, we compared allometric patterns of early limb growth of four distantly related species of lizards. The major questions addressed were whether early embryonic limb and tail growth is characterized by the gradual (continuous allometry) or by the abrupt emergence (transpositional allometry) of size differences among species. Our observations supported transpositional allometry of both limbs and tails. Species-specific differences in limb and tail length were exhibited when limb and tail buds first protruded from the body wall. Genes known to be associated with early limb development of tetrapods are obvious targets for studies on the genetic mechanisms that determine interspecific differences in relative limb length. Broadly comparative studies of gene regulation would facilitate understanding of the mechanisms underlying adaptive variation in limb size, including limb reduction and loss, of squamate reptiles. © 2017 Wiley Periodicals, Inc.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bhardwaj, A.; Walker-Kopp, N; Casjens, S
2009-01-01
Bacteriophages of the Podoviridae family use short noncontractile tails to inject their genetic material into Gram-negative bacteria. In phage P22, the tail contains a thin needle, encoded by the phage gene 26, which is essential both for stabilization and for ejection of the packaged viral genome. Bioinformatic analysis of the N-terminal domain of gp26 (residues 1-60) led us to identify a family of genes encoding putative homologues of the tail needle gp26. To validate this idea experimentally and to explore their diversity, we cloned the gp26-like gene from phages HK620, Sf6 and HS1, and characterized these gene products in solution.more » All gp26-like factors contain an elongated {alpha}-helical coiled-coil core consisting of repeating, adjacent trimerization heptads and form trimeric fibers with length ranging between about 240 to 300 {angstrom}. gp26 tail needles display a high level of structural stability in solution, with Tm (temperature of melting) between 85 and 95 C. To determine how the structural stability of these phage fibers correlates with the length of the {alpha}-helical core, we investigated the effect of insertions and deletions in the helical core. In the P22 tail needle, we identified an 85-residue-long helical domain, termed MiCRU (minimal coiled-coil repeat unit), that can be inserted in-frame inside the gp26 helical core, preserving the straight morphology of the fiber. Likewise, we were able to remove three quarters of the helical core of the HS1 tail needle, minimally decreasing the stability of the fiber. We conclude that in the gp26 family of tail needles, structural stability increases nonlinearly with the length of the {alpha}-helical core. Thus, the overall stability of these bacteriophage fibers is not solely dependent on the number of trimerization repeats in the {alpha}-helical core.« less
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Roy, Arundhati; Saha, Tanmoy; Gening, Marina L; Titov, Denis V; Gerbst, Alexey G; Tsvetkov, Yury E; Nifantiev, Nikolay E; Talukdar, Pinaki
2015-11-23
Cyclo-oligo-(1→6)-β-D-glucosamines functionalized with hydrophobic tails are reported as a new class of transmembrane ion-transport system. These macrocycles with hydrophilic cavities were introduced as an alternative to cyclodextrins, which are supramolecular systems with hydrophobic cavities. The transport activities of these glycoconjugates were manipulated by altering the oligomericity of the macrocycles, as well as the length and number of attached tails. Hydrophobic tails of 3 different sizes were synthesized and coupled with each glucosamine scaffold through the amide linkage to obtain 18 derivatives. The ion-transport activity increased from di- to tetrameric glucosamine macrocycles, but decreased further when flexible pentameric glucosamine was introduced. The ion-transport activity also increased with increasing length of attached linkers. For a fixed length of linkers, the transport activity decreased when the number of such tails was reduced. All glycoconjugates displayed a uniform anion-selectivity sequence: Cl(-) >Br(-) >I(-) . From theoretical studies, hydrogen bonding between the macrocycle backbone and the anion bridged through water molecules was observed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Santiago, Hildemberg Agostinho Rocha de; De Pierro, Lucas Rodolfo; Reis, Rafael Menezes; Caluz, Antônio Gabriel Ricardo Engracia; Ribeiro, Victor Barbosa; Volpon, José Batista
2015-11-01
To investigate allometric relationships among body mass (BM), muzzle-tail length (MTL), and tibia length (TL) in Wistar rats and establish their growth rate change parameters. Eighteen male and 18 female Wistar rats were studied from the 3rd to the 21st week of age. BM, MTL, and TL were measured daily, and relative growth was compared using allometry. A positive correlation between BM and MTL (p<0.05) and BM and TL (p<0.05) was observed. Males and females showed comparable curves; however, females had turning points at a younger age. The allometric relationship between BM and MTL presented a regular increase until reaching a mass of 351 g (males) and 405 g (females). BM and TL showed an initial increase until 185 g (males) and 182 g (females), and then reached a plateau that finished at 412 g (males) and 334 g (females), to display another increase. The allometric relationship of body mass with animal length and tibia length was comparable for male and female rats, with female rats maturing earlier. Animal longitudinal growth occurred in a single stage. In contrast, tibia length depicted two stages of accelerated growth with an intermediate period of deceleration.
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Molecular modeling of proteinlike inclusions in lipid bilayers: lipid-mediated interactions.
Kik, Richard A; Leermakers, Frans A M; Kleijn, J Mieke
2010-02-01
We investigated the insertion of transmembrane structures in a lipid bilayer and their interactions using self-consistent field theory. The lipids are coarse-grained on a united-atom level and consist of a phosphatidylcholinelike headgroup and two hydrophobic tails. The inclusions, acting as simple models for proteins that span biological membranes, are rigid rods (radius R ) with a hydrophobic surface and hydrophilic end caps. The insertion free energy Omega of an individual rod is strongly regulated by the affinity between its hydrophobic surface and the lipid tails. This affinity also controls the best match of the hydrophobic length of the rod with that of the bilayer. The line tension tau(=Omega/2piR) is practically independent of R . The perturbations in the bilayer as a function of distance from the inclusion, have the shape of a damped oscillation. The wavelength and decay length are related to the elastic properties of the bilayer and do not depend on R . These results are used to analyze how the lipid matrix affects the interaction between transmembrane objects, for computational reasons considering the limit of R-->infinity . Contributions on different length scales can be distinguished: (i) a long-range elastic interaction, which is an exponentially decaying oscillation; (ii) an exponentially decaying repulsion on an intermediate length scale, resulting from the loss of conformational entropy of the lipid tails; and (iii) a short-range interaction due to the finite compressibility of the lipid tails, which manifests either as a depletion attraction if there is no affinity between the tails and the inclusions' surface or, otherwise, as an oscillatory structural force.
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Pendular motion in the brachiation of captive Lagothrix and Ateles.
Turnquist, J E; Schmitt, D; Rose, M D; Cant, J G
1999-01-01
Pendular motion during brachiation of captive Lagothrix lagothricha lugens and Ateles fusciceps robustus was analyzed to demonstrate similarities, and differences, between these two closely related large bodied atelines. This is the first captive study of the kinematics of brachiation in Lagothrix. Videorecordings of one adult male of each species were made in a specially designed cage constructed at the DuMond Conservancy/Monkey Jungle, Miami, FL. Java software (Jandel Scientific Inc., San Rafael, CA) was used for frame-by-frame kinematic analysis of individual strides/steps. Results demonstrate that the sequence of hand and tail contacts differ significantly between the two species with Lagothrix using a new tail hold with every hand hold, while Ateles generally utilizes a new tail hold with only every other hand hold. Stride length and stride frequency, even after adjusting for limb length, also differ significantly between the two species. Lagothrix brachiation utilizes short, choppy strides with quick hand holds, while Ateles uses long, fluid strides with longer hand holds. During brachiation not only is Lagothrix's body significantly less horizontal than that of Ateles but also, within Ateles, there are significant differences between steps depending on tail use. Because of the unique nature of tail use in Ateles, many aspects of body positioning in Lagothrix more closely resemble Ateles steps without a simultaneous tail hold rather than those with one. Overall pendulum length in Lagothrix is shorter than in Ateles. Tail use in Ateles has a significant effect on maximum pendulum length during a step. Although neither species achieves the extreme pendulum effect and long period of free-flight of hylobatids in fast ricochetal brachiation, in captivity both consistently demonstrate effective brachiation with brief periods of free-flight and pendular motion. Morphological similarities between ateline brachiators and hylobatids are fewer and less pronounced in Lagothrix than in Ateles. This study demonstrates that Lagothrix brachiation is also less hylobatid-like than that of Ateles.
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Semler, Matthew R; Wiseman, Roger W; Karl, Julie A; Graham, Michael E; Gieger, Samantha M; O'Connor, David H
2018-06-01
Pig-tailed macaques (Macaca nemestrina, Mane) are important models for human immunodeficiency virus (HIV) studies. Their infectability with minimally modified HIV makes them a uniquely valuable animal model to mimic human infection with HIV and progression to acquired immunodeficiency syndrome (AIDS). However, variation in the pig-tailed macaque major histocompatibility complex (MHC) and the impact of individual transcripts on the pathogenesis of HIV and other infectious diseases is understudied compared to that of rhesus and cynomolgus macaques. In this study, we used Pacific Biosciences single-molecule real-time circular consensus sequencing to describe full-length MHC class I (MHC-I) transcripts for 194 pig-tailed macaques from three breeding centers. We then used the full-length sequences to infer Mane-A and Mane-B haplotypes containing groups of MHC-I transcripts that co-segregate due to physical linkage. In total, we characterized full-length open reading frames (ORFs) for 313 Mane-A, Mane-B, and Mane-I sequences that defined 86 Mane-A and 106 Mane-B MHC-I haplotypes. Pacific Biosciences technology allows us to resolve these Mane-A and Mane-B haplotypes to the level of synonymous allelic variants. The newly defined haplotypes and transcript sequences containing full-length ORFs provide an important resource for infectious disease researchers as certain MHC haplotypes have been shown to provide exceptional control of simian immunodeficiency virus (SIV) replication and prevention of AIDS-like disease in nonhuman primates. The increased allelic resolution provided by Pacific Biosciences sequencing also benefits transplant research by allowing researchers to more specifically match haplotypes between donors and recipients to the level of nonsynonymous allelic variation, thus reducing the risk of graft-versus-host disease.
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Li, Xiaofang; Zhu, Yong-Guan; Shaban, Babak; Bruxner, Timothy J. C.; Bond, Philip L.; Huang, Longbin
2015-01-01
Characterizing the genetic diversity of microbial copper (Cu) resistance at the community level remains challenging, mainly due to the polymorphism of the core functional gene copA. In this study, a local BLASTN method using a copA database built in this study was developed to recover full-length putative copA sequences from an assembled tailings metagenome; these sequences were then screened for potentially functioning CopA using conserved metal-binding motifs, inferred by evolutionary trace analysis of CopA sequences from known Cu resistant microorganisms. In total, 99 putative copA sequences were recovered from the tailings metagenome, out of which 70 were found with high potential to be functioning in Cu resistance. Phylogenetic analysis of selected copA sequences detected in the tailings metagenome showed that topology of the copA phylogeny is largely congruent with that of the 16S-based phylogeny of the tailings microbial community obtained in our previous study, indicating that the development of copA diversity in the tailings might be mainly through vertical descent with few lateral gene transfer events. The method established here can be used to explore copA (and potentially other metal resistance genes) diversity in any metagenome and has the potential to exhaust the full-length gene sequences for downstream analyses. PMID:26286020
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New evidence from China for the nature of the pterosaur evolutionary transition
NASA Astrophysics Data System (ADS)
Wang, Xiaoli; Jiang, Shunxing; Zhang, Junqiang; Cheng, Xin; Yu, Xuefeng; Li, Yameng; Wei, Guangjin; Wang, Xiaolin
2017-02-01
Pterosaurs are extinct flying reptiles, the first vertebrates to achieve powered flight. Our understanding of the evolutionary transition between basal, predominantly long-tailed forms to derived short-tailed pterodactyloids remained poor until the discovery of Wukongopterus and Darwinopterus in western Liaoning, China. In this paper we report on a new genus and species, Douzhanopterus zhengi, that has a reduced tail, 173% the length of the humerus, and a reduced fifth pedal digit, whose first phalange is ca. 20% the length of metatarsal III, both unique characters to Monofenestra. The morphological comparisons and phylogenetic analysis presented in this paper demonstrate that Douzhanopterus is the sister group to the ‘Painten pro-pterodactyloid’ and the Pterodactyloidea, reducing the evolutionary gap between long- and short-tailed pterosaurs.
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Citral degradation in micellar structures formed with polyoxyethylene-type surfactants.
Park, Sung Joon; Hong, Chi Rac; Choi, Seung Jun
2015-03-01
In a micellar solution, the chemical degradation of poorly water-soluble food flavours can be influenced by the properties of the surfactants forming the micelles in aqueous solutions. To evaluate how hydrophilic head size and hydrophobic tail length influence the chemical degradation rate of food flavour, micelles were prepared with Brij surfactants (Brij 35, 58, 78 and 700), each of which had very similar molecular structures (polyoxyethylene fatty acid ether). The chemical degradation of citral in Brij micelles was found to be highest in an acidic environment. There was no significant difference in the chemical degradation rate of citral in Brij micelles in non-acidic conditions, regardless of the hydrophilic head size or hydrophobic tail length. Brij surfactants with larger hydrophilic heads effectively retarded the chemical degradation of citral in an acidic environment. Our findings suggest that the length of the hydrophobic tail rarely influenced the micelle's ability to chemically stabilize citral. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Spermatozoon structure and motility in the anuran Lepidobatrachus laevis.
Waggener, W L; Carroll, E J
1998-02-01
Synthetic human gonadotropin releasing hormone (GnRH) injections were used for induction of spermatozoon release followed by cloacal lavage or mechanical stimulation of sperm release in Lepidobatrachus laevis. Light microscopic observations of Lepidobatrachus laevis spermatozoa indicated an acrosomal segment with a length of 4.1 microm delineated by an indentation, a nuclear region of 12.6 microm in length and a midpiece of 0.87 microm in length. The tail was 54.9 microm long by 1.35 microm wide with two lateral axial fibers and a central undulating membrane. At the electron microscopic level, the unusual tail had two complete axonemes that emanated from the distal centriole. The tail also contained two axial fibers 77 nm in diameter medial to the axonemes and was connected by an undulating membrane. An unusual accessory cell adherent to the head of the spermatozoon was noted in freshly obtained suspensions of spermatozoa. Spermatozoa with the accessory cell were motile and a subsequent loss of motility was correlated with the shedding of the accessory cell.
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Genotoxic effects of glyphosate or paraquat on earthworm coelomocytes.
Muangphra, Ptumporn; Kwankua, Wimon; Gooneratne, Ravi
2014-06-01
The potential genotoxicity (nuclear anomalies, damage to single-strand DNA) and pinocytic adherence activity of two (glyphosate-based and paraquat-based) commercial herbicides to earthworm coelomocytes (immune cells in the coelomic cavity) were assessed. Coelomocytes were extracted from earthworms (Pheretima peguana) exposed to concentrations
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Cetinkaya, Nurcan; Ercin, Demet; Özvatan, Sümer; Erel, Yakup
2016-02-01
The experiments were conducted for quantification of applied dose for quarantine control in irradiated citrus fruits. Citrus fruits exposed to doses of 0.1 to 1.5 kGy and analyzed by DNA Comet Assay. Observed comets were evaluated by image analysis. The tail length, tail moment and tail DNA% of comets were used for the interpretation of comets. Irradiated citrus fruits showed the separated tails from the head of the comet by increasing applied doses from 0.1 to 1.5 kGy. The mean tail length and mean tail moment% levels of irradiated citrus fruits at all doses are significantly different (p < 0.01) from control even for the lowest dose at 0.1 kGy. Thus, DNA Comet Assay may be a practical quarantine control method for irradiated citrus fruits since it has been possible to estimate the applied low doses as small as 0.1 kGy when it is combined with image analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Ye, Weimin; Robbins, R. T.
2004-01-01
Hierarchical cluster analysis based on female morphometric character means including body length, distance from vulva opening to anterior end, head width, odontostyle length, esophagus length, body width, tail length, and tail width were used to examine the morphometric relationships and create dendrograms for (i) 62 populations belonging to 9 Longidorus species from Arkansas, (ii) 137 published Longidorus species, and (iii) 137 published Longidorus species plus 86 populations of 16 Longidorus species from Arkansas and various other locations by using JMP 4.02 software (SAS Institute, Cary, NC). Cluster analysis dendograms visually illustrated the grouping and morphometric relationships of the species and populations. It provided a computerized statistical approach to assist by helping to identify and distinguish species, by indicating morphometric relationships among species, and by assisting with new species diagnosis. The preliminary species identification can be accomplished by running cluster analysis for unknown species together with the data matrix of known published Longidorus species. PMID:19262809
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Wotherspoon, Danny; Burgin, Shelley
2011-02-01
The functional significance of allometric change in reptiles has received limited attention and the reason for such changes has been regarded as 'obscure'. In this paper we report data on the Australian Pogona barbata, the eastern bearded dragon, from across their range and review changes in allometric growth among juveniles, and adult males and females and consider the functional relevance of these changes. There were significant differences in the population for mass, tail length, tail width, rear leg length and jaw length. These differences were consistent with differences required in locomotor performance and thus habitat use, together with access to different preferred dietary components. Crown Copyright © 2011. Published by Elsevier GmbH. All rights reserved.
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Endogenous DNA damage and testicular germ cell tumors
Cook, Michael B.; Sigurdson, Alice J.; Jones, Irene M.; Thomas, Cynthia B.; Graubard, Barry I.; Korde, Larissa; Greene, Mark H.; McGlynn, Katherine A.
2008-01-01
Testicular germ cell tumors (TGCT) are comprised of two histologic groups, seminomas and nonseminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable levels of net endogenous DNA damage. To test our hypothesis, we conducted a case-case analysis of 51 seminoma and 61 nonseminoma patients using data and specimens from the Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort. A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modeled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with nonseminoma compared to seminoma (OR50th percentile=3.31, 95%CI: 1.00, 10.98; OR75th percentile=3.71, 95%CI: 1.04, 13.20; p for trend=0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR50th percentile=2.27, 95%CI: 0.75, 6.87; OR75th percentile=2.40, 95%CI: 0.75, 7.71; p for trend=0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that net endogenous levels are higher in patients who develop nonseminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma. PMID:18657195
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Specimen dimensions influence the measurement of material properties in tendon fascicles.
Legerlotz, Kirsten; Riley, Graham P; Screen, Hazel R C
2010-08-26
Stress, strain and modulus are regularly used to characterize material properties of tissue samples. However, when comparing results from different studies it is evident the reported material properties, particularly failure strains, vary hugely. The aim of our study was to characterize how and why specimen length and cross-sectional area (CSA) appear to influence failure stress, strain and modulus in fascicles from two functionally different tendons. Fascicles were dissected from five rat tails and five bovine foot extensors, their diameters determined by a laser micrometer, and loaded to failure at a range of grip-to-grip lengths. Strain to failure significantly decreased with increasing in specimen length in both rat and bovine fascicles, while modulus increased. Specimen length did not influence failure stress in rat tail fascicles, although in bovine fascicles it was significantly lower in the longer 40 mm specimens compared to 5 and 10mm specimens. The variations in failure strain and modulus with sample length could be predominantly explained by end-effects. However, it was also evident that strain fields along the sample length were highly variable and notably larger towards the ends of the sample than the mid-section even at distances in excess of 5mm from the gripping points. Failure strain, stress and modulus correlated significantly with CSA at certain specimen lengths. Our findings have implications for the mechanical testing of tendon tissue: while it is not always possible to control for fascicle length and/or CSA, these parameters have to be taken into account when comparing samples of different dimensions. 2010 Elsevier Ltd. All rights reserved.
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Poly(A) tail length regulates PABPC1 expression to tune translation in the heart.
Chorghade, Sandip; Seimetz, Joseph; Emmons, Russell; Yang, Jing; Bresson, Stefan M; Lisio, Michael De; Parise, Gianni; Conrad, Nicholas K; Kalsotra, Auinash
2017-06-27
The rate of protein synthesis in the adult heart is one of the lowest in mammalian tissues, but it increases substantially in response to stress and hypertrophic stimuli through largely obscure mechanisms. Here, we demonstrate that regulated expression of cytosolic poly(A)-binding protein 1 (PABPC1) modulates protein synthetic capacity of the mammalian heart. We uncover a poly(A) tail-based regulatory mechanism that dynamically controls PABPC1 protein synthesis in cardiomyocytes and thereby titrates cellular translation in response to developmental and hypertrophic cues. Our findings identify PABPC1 as a direct regulator of cardiac hypertrophy and define a new paradigm of gene regulation in the heart, where controlled changes in poly(A) tail length influence mRNA translation.
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Hong, Chi Rac; Park, Sung Joon; Choi, Seung Jun
2016-07-01
Surfactant-made micelles can control the rate of chemical degradation of poorly water-soluble food flavors. To evaluate how the molecular structure of surfactant has an influence on the chemical decomposition rate of citral, micelles were prepared with polyoxyethylene alkyl ether-type surfactants that had similar molecular structures but various hydrophilic head sizes and hydrophobic tail lengths. At a critical 20× micelle concentration of surfactant, there was no significant difference in the chemical degradation rate of citral in micelles in neutral pH, regardless of the hydrophilic head size or hydrophobic tail length. In an acidic environment, the degradation rate constant of citral generally increased proportionally with increasing hydrophilic head size of surfactant (0.1563 and 0.2217 for surfactants with 23 and 100 oxyethylene units, respectively) but the length of hydrophobic tail did not affect the citral stability. Also, little difference (0.2217 and 0.2265 for surfactant having 100 oxyethylene units with and without Fe(3+) ) in degradation rate constant of citral between simple micellar solution and micellar solution containing iron suggested that iron ions could not accelerate citral degradation in micelles, regardless of the form of iron (Fe(2+) and Fe(3+) ). This work concludes that although the concentration of surfactant could be relevant, if its concentration could be controlled in the same manner as the critical micelle concentration, then a polyethylene alkyl ether-type surfactant with a small hydrophilic head could more efficiently stabilize citral at an acidic pH. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.
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50 CFR 648.93 - Monkfish minimum fish sizes.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 50 Wildlife and Fisheries 12 2012-10-01 2012-10-01 false Monkfish minimum fish sizes. 648.93... Measures for the NE Multispecies and Monkfish Fisheries § 648.93 Monkfish minimum fish sizes. (a) General... fish size requirements established in this section. Minimum Fish Sizes (Total Length/Tail Length) Total...
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50 CFR 648.93 - Monkfish minimum fish sizes.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 50 Wildlife and Fisheries 12 2013-10-01 2013-10-01 false Monkfish minimum fish sizes. 648.93... Measures for the NE Multispecies and Monkfish Fisheries § 648.93 Monkfish minimum fish sizes. (a) General... fish size requirements established in this section. Minimum Fish Sizes (Total Length/Tail Length) Total...
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50 CFR 648.93 - Monkfish minimum fish sizes.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Monkfish minimum fish sizes. 648.93... Measures for the NE Multispecies and Monkfish Fisheries § 648.93 Monkfish minimum fish sizes. (a) General... fish size requirements established in this section. Minimum Fish Sizes (Total Length/Tail Length) Total...
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50 CFR 648.93 - Monkfish minimum fish sizes.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Monkfish minimum fish sizes. 648.93... Measures for the NE Multispecies and Monkfish Fisheries § 648.93 Monkfish minimum fish sizes. (a) General... fish size requirements established in this section. Minimum Fish Sizes (Total Length/Tail Length) Total...
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Mamur, Sevcan; Unal, Fatma; Altok, Kadriye; Deger, Serpil Muge; Yuzbasioglu, Deniz
2016-04-01
The incidence of chronic kidney disease (CKD) is increasing rapidly. Diabetes mellitus (DM) is the most important cause of CKD. We studied the possible role of DM in CKD patients with respect to DNA damage, as assessed by the comet assay in 60 CKD patients (with or without DM) undergoing hemodialysis and in 26 controls. Effects of other factors, such as age, sex, hypertension, duration of hemodialysis, body mass index (BMI), and levels of hemoglobin (HB), intact parathormone (iPTH), and ferritin (FER), were also examined. Primary DNA damage measured by the comet assay was significantly higher in CKD patients than in controls. Among CKD patients, the following correlations were observed. (1) There was no difference in comet tail length or tail intensity between diabetic and non-diabetic individuals. (2) Age, sex, hemoglobin, hypertension, duration of hemodialysis, and ferritin levels affected neither tail length nor intensity. (3) BMI values above 25kg/m(2) and iPTH levels above 300pg/ml were associated with significantly greater comet tail length. Our results indicate that primary DNA damage is increased in CKD patients undergoing hemodialysis, compared to controls; however, DM had no additional effect. Copyright © 2016. Published by Elsevier B.V.
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The ultimate and proximate mechanisms driving the evolution of long tails in forest deer mice
Kingsley, Evan P.; Kozak, Krzysztof M.; Pfeifer, Susanne P.; Yang, Dou‐Shuan; Hoekstra, Hopi E.
2016-01-01
Understanding both the role of selection in driving phenotypic change and its underlying genetic basis remain major challenges in evolutionary biology. Here, we use modern tools to revisit a classic system of local adaptation in the North American deer mouse, Peromyscus maniculatus, which occupies two main habitat types: prairie and forest. Using historical collections, we find that forest‐dwelling mice have longer tails than those from nonforested habitat, even when we account for individual and population relatedness. Using genome‐wide SNP data, we show that mice from forested habitats in the eastern and western parts of their range form separate clades, suggesting that increased tail length evolved independently. We find that forest mice in the east and west have both more and longer caudal vertebrae, but not trunk vertebrae, than nearby prairie forms. By intercrossing prairie and forest mice, we show that the number and length of caudal vertebrae are not correlated in this recombinant population, indicating that variation in these traits is controlled by separate genetic loci. Together, these results demonstrate convergent evolution of the long‐tailed forest phenotype through two distinct genetic mechanisms, affecting number and length of vertebrae, and suggest that these morphological changes—either independently or together—are adaptive. PMID:27958661
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Micellization Behavior of Long-Chain Substituted Alkylguanidinium Surfactants
Bouchal, Roza; Hamel, Abdellah; Hesemann, Peter; In, Martin; Prelot, Bénédicte; Zajac, Jerzy
2016-01-01
Surface activity and micelle formation of alkylguanidinium chlorides containing 10, 12, 14 and 16 carbon atoms in the hydrophobic tail were studied by combining conductivity and surface tension measurements with isothermal titration calorimetry. The purity of the resulting surfactants, their temperatures of Cr→LC and LC→I transitions, as well as their propensity of forming birefringent phases, were assessed based on the results of 1H and 13C NMR, differential scanning calorimetry (DSC), and polarizing microscopy studies. Whenever possible, the resulting values of Krafft temperature (TK), critical micelle concentration (CMC), minimum surface tension above the CMC, chloride counter-ion binding to the micelle, and the standard enthalpy of micelle formation per mole of surfactant (ΔmicH°) were compared to those characterizing alkyltrimethylammonium chlorides or bromides with the same tail lengths. The value of TK ranged between 292 and 314 K and increased strongly with the increase in the chain length of the hydrophobic tail. Micellization was described as both entropy and enthalpy-driven. Based on the direct calorimetry measurements, the general trends in the CMC with the temperature, hydrophobic tail length, and NaCl addition were found to be similar to those of other types of cationic surfactants. The particularly exothermic character of micellization was ascribed to the hydrogen-binding capacity of the guanidinium head-group. PMID:26861309
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Lian, Hui-Yong; Robertson, E Douglas; Hiraga, Shin-ichiro; Alvino, Gina M; Collingwood, David; McCune, Heather J; Sridhar, Akila; Brewer, Bonita J; Raghuraman, M K; Donaldson, Anne D
2011-05-15
DNA replication in Saccharomyces cerevisiae proceeds according to a temporal program. We have investigated the role of the telomere-binding Ku complex in specifying late replication of telomere-proximal sequences. Genome-wide analysis shows that regions extending up to 80 kb from telomeres replicate abnormally early in a yku70 mutant. We find that Ku does not appear to regulate replication time by binding replication origins directly, nor is its effect on telomere replication timing mediated by histone tail acetylation. We show that Ku instead regulates replication timing through its effect on telomere length, because deletion of the telomerase regulator Pif1 largely reverses the short telomere defect of a yku70 mutant and simultaneously rescues its replication timing defect. Consistent with this conclusion, deleting the genome integrity component Elg1 partially rescued both length and replication timing of yku70 telomeres. Telomere length-mediated control of replication timing requires the TG(1-3) repeat-counting component Rif1, because a rif1 mutant replicates telomeric regions early, despite having extended TG(1-3) tracts. Overall, our results suggest that the effect of Ku on telomere replication timing results from its impact on TG(1-3) repeat length and support a model in which Rif1 measures telomere repeat length to ensure that telomere replication timing is correctly programmed.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Serwer, Philip, E-mail: serwer@uthscsa.edu; Wright, Elena T.; Liu, Zheng
DNA packaging of phages phi29, T3 and T7 sometimes produces incompletely packaged DNA with quantized lengths, based on gel electrophoretic band formation. We discover here a packaging ATPase-free, in vitro model for packaged DNA length quantization. We use directed evolution to isolate a five-site T3 point mutant that hyper-produces tail-free capsids with mature DNA (heads). Three tail gene mutations, but no head gene mutations, are present. A variable-length DNA segment leaks from some mutant heads, based on DNase I-protection assay and electron microscopy. The protected DNA segment has quantized lengths, based on restriction endonuclease analysis: six sharp bands of DNAmore » missing 3.7–12.3% of the last end packaged. Native gel electrophoresis confirms quantized DNA expulsion and, after removal of external DNA, provides evidence that capsid radius is the quantization-ruler. Capsid-based DNA length quantization possibly evolved via selection for stalling that provides time for feedback control during DNA packaging and injection. - Graphical abstract: Highlights: • We implement directed evolution- and DNA-sequencing-based phage assembly genetics. • We purify stable, mutant phage heads with a partially leaked mature DNA molecule. • Native gels and DNase-protection show leaked DNA segments to have quantized lengths. • Native gels after DNase I-removal of leaked DNA reveal the capsids to vary in radius. • Thus, we hypothesize leaked DNA quantization via variably quantized capsid radius.« less
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Lehmer, E.M.; Biggins, D.E.
2005-01-01
We compared over-winter body temperature (Tb) patterns for more than 6 months in adult (> 1 year) black-tailed (Cynomys ludovicianus) and Utah (C. parvidens) prairie dogs from colonies located along gradients of elevation in northern Colorado and southern Utah. In general, black-tailed prairie dogs entered torpor facultatively during winter, whereas Utah prairie dogs hibernated continuously for extended periods. Both black-tailed and Utah prairie dogs displayed significant differences in Tb patterns across elevations, with lower elevation populations entering more shallow and infrequent torpor than prairie dogs at higher elevations. Tb patterns of black-tailed prairie dogs followed 24-h cycles, as most prairie dogs entered into and aroused from torpor between 1100 and 1700 h and bout lengths were clustered around 24-h intervals and multiples thereof. Torpor in Utah prairie dogs did not display the same daily patterns; they entered into and aroused from torpor at all times of the day, and bout lengths were variable. Although black-tailed and Utah prairie dogs are closely related, mechanisms that stimulate and control torpor might differ between them.
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Dennehey, Briana K.; Noone, Seth; Liu, Wallace H.; Smith, Luke
2013-01-01
The central histone H3/H4 chaperone Asf1 comprises a highly conserved globular core and a divergent C-terminal tail. While the function and structure of the Asf1 core are well known, the function of the tail is less well understood. Here, we have explored the role of the yeast (yAsf1) and human (hAsf1a and hAsf1b) Asf1 tails in Saccharomyces cerevisiae. We show, using a photoreactive, unnatural amino acid, that Asf1 tail residue 210 cross-links to histone H3 in vivo and, further, that loss of C-terminal tail residues 211 to 279 weakens yAsf1-histone binding affinity in vitro nearly 200-fold. Via several yAsf1 C-terminal truncations and yeast-human chimeric proteins, we found that truncations at residue 210 increase transcriptional silencing and that the hAsf1a tail partially substitutes for full-length yAsf1 with respect to silencing but that full-length hAsf1b is a better overall substitute for full-length yAsf1. In addition, we show that the C-terminal tail of Asf1 is phosphorylated at T270 in yeast. Loss of this phosphorylation site does not prevent coimmunoprecipitation of yAsf1 and Rad53 from yeast extracts, whereas amino acid residue substitutions at the Asf1-histone H3/H4 interface do. Finally, we show that residue substitutions in yAsf1 near the CAF-1/HIRA interface also influence yAsf1's function in silencing. PMID:23184661
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Structure-delivery relationships of lysine-based gemini surfactants and their lipoplexes.
Damen, Mark; Cristóbal-Lecina, Edgar; Sanmartí, Glòria Colom; van Dongen, Stijn F M; García Rodríguez, Cristina L; Dolbnya, Igor P; Nolte, Roeland J M; Feiters, Martin C
2014-08-21
The synthesis and properties of gemini surfactants of the type (R(1)(CO)-Lys(H)-NH)2(CH2)n are reported. For a spacer length of n = 6, the hydrophobic acyl tail was varied in length (R(1) = C8, C10, C12, C14, C16, and C18) and, for R(1) = C18, the degree of unsaturation. For R(1)(CO) = oleoyl (C18:1 Z) the spacer length (n = 2-8) and the stereochemistry of the lysine building block were varied; a 'half-gemini' derivative with a single oleoyl tail and head group was also prepared. The potential of the gemini surfactants to transfer polynucleotides across a cell membrane was investigated by transfection of HeLa cells with beta-galactosidase, both in the presence and absence of the helper lipid DOPE. Oleoyl was found to be by far the best hydrophobic tail for this biological activity, whereas the effect of the lysine stereochemistry was less pronounced. The effect of an optimum spacer length (n = 6) was observed only in the absence of helper lipid. The most active surfactant, i.e. the one with oleoyl chains and n = 6, formed liposomes with sizes in the range of 60-350 nm, and its lipoplex underwent a transition from a lamellar to a hexagonal morphology upon lowering the pH from 7 to 3.
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McGlothlin, Joel W; Parker, Patricia G; Nolan, Val; Ketterson, Ellen D
2005-03-01
When a trait's effect on fitness depends on its interaction with other traits, the resultant selection is correlational and may lead to the integration of functionally related traits. In relation to sexual selection, when an ornamental trait interacts with phenotypic quality to determine mating success, correlational sexual selection should generate genetic correlations between the ornament and quality, leading to the evolution of honest signals. Despite its potential importance in the evolution of signal honesty, correlational sexual selection has rarely been measured in natural populations. In the dark-eyed junco (Junco hyemalis), males with experimentally elevated values of a plumage trait (whiteness in the tail or "tail white") are more attractive to females and dominant in aggressive encounters over resources. We used restricted maximum-likelihood analysis of a long-term dataset to measure the heritability of tail white and two components of body size (wing length and tail length), as well as genetic correlations between pairs of these traits. We then used multiple regression to assess directional, quadratic, and correlational selection as they acted on tail white and body size via four components of lifetime fitness (juvenile and adult survival, mating success, and fecundity). We found a positive genetic correlation between tail white and body size (as measured by wing length), which indicates past correlational selection. Correlational selection, which was largely due to sexual selection on males, was also found to be currently acting on the same pair of traits. Larger males with whiter tails sired young with more females, most likely due to a combination of female choice, which favors males with whiter tails, and male-male competition, which favors both tail white and larger body size. To our knowledge, this is the first study to show both genetic correlations between sexually selected traits and currently acting correlational sexual selection, and we suggest that correlational sexual selection frequently may be an important mechanism for maintaining the honesty of sexual signals.
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Tail position affects the body temperature of rats during cold exposure in a low-energy state.
Uchida, Yuki; Tokizawa, Ken; Nakamura, Mayumi; Lin, Cheng-Hsien; Nagashima, Kei
2012-02-01
Rats place their tails underneath their body trunks when cold (tail-hiding behavior). The aim of the present study was to determine whether this behavior is necessary to maintain body temperature. Male Wistar rats were divided into 'fed' and '42-h fasting' groups. A one-piece tail holder (8.4 cm in length) that prevented the tail-hiding behavior or a three-piece tail holder (2.8 cm in length) that allowed for the tail-hiding behavior was attached to the tails of the rats. The rats were exposed to 27°C for 180 min or to 20°C for 90 min followed by 15°C for 90 min with continuous body temperature and oxygen consumption measurements. Body temperature decreased by -1.0 ± 0.1°C at 15°C only in the rats that prevented tail-hiding behavior of the 42-h fasting group, and oxygen consumption increased at 15°C in all animals. Oxygen consumption was not different between the rats that prevented tail-hiding behavior and the rats that allowed the behavior in the fed and 42-h fasting groups under ambient conditions. These results show that the tail-hiding behavior is involved in thermoregulation in the cold in fasting rats.
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Rrp6p controls mRNA polyA tail length and its decoration with polyA binding proteins
Schmid, Manfred; Poulsen, Mathias Bach; Olszewski, Pawel; Pelechano, Vicent; Saguez, Cyril; Gupta, Ishaan; Steinmetz, Lars M.; Moore, Claire; Jensen, Torben Heick
2012-01-01
PolyA (pA) tail binding proteins (PABPs) control mRNA polyadenylation, stability and translation. In a purified system, S. cerevisiae PABPs, Pab1p and Nab2p, are individually sufficient to provide normal pA tail length. However, it is unknown how this occurs in more complex environments. Here we find that the nuclear exosome subunit Rrp6p counteracts the in vitro and in vivo extension of mature pA tails by the non-canonical pA polymerase Trf4p. Moreover, PABP loading onto nascent pA tails is controlled by Rrp6p; while Pab1p is the major PABP, Nab2p only associates in the absence of Rrp6p. This is because Rrp6p can interact with Nab2p and displace it from pA tails, potentially leading to RNA turnover as evidenced for certain pre-mRNAs. We suggest that a nuclear mRNP surveillance step involves targeting of Rrp6p by Nab2p-bound pA-tailed RNPs and that pre-mRNA abundance is regulated at this level. PMID:22683267
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Liégeois, Florian; Butel, Christelle; Mouinga-Ondéme, Augustin; Verrier, Delphine; Motsch, Peggy; Gonzalez, Jean-Paul; Peeters, Martine; Rouet, François; Onanga, Richard
2011-11-01
Since the first characterization of SIVsun (L14 strain) from a sun-tailed monkey (Cercopithecus solatus) in Gabon in 1999, no further information exists about the evolutionary history and geographic distribution of this lentivirus. Here, we report the full-length molecular characterization of a second SIVsun virus (SIVsunK08) naturally infecting a wild-caught sun-tailed monkey. The SIVsunK08 strain was most closely related to SIVsunL14 and clustered with members of the SIVmnd-1/SIVlhoest group. SIVsunK08 shared identical functional motifs in the LTR, Gag and Env proteins with SIVsunL14. Our data indicate that C. solatus is naturally infected with a monophyletic SIVsun strain.
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NASA Technical Reports Server (NTRS)
Burk, S. M., Jr.; Bowman, J. S., Jr.; White, W. L.
1977-01-01
A spin tunnel study is reported on a scale model of a research airplane typical of low-wing, single-engine, light general aviation airplanes to determine the tail parachute diameter and canopy distance (riser length plus suspension-line length) required for energency spin recovery. Nine tail configurations were tested, resulting in a wide range of developed spin conditions, including steep spins and flat spins. The results indicate that the full-scale parachute diameter required for satisfactory recovery from the most critical conditions investigated is about 3.2 m and that the canopy distance, which was found to be critical for flat spins, should be between 4.6 and 6.1 m.
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A PERSISTENT BONE GROWTH DEFICIT IN THE X-IRRADIATED RAT
DOE Office of Scientific and Technical Information (OSTI.GOV)
Phillips, R.D.; Kimeldorf, D.J.
1964-02-10
ABS>A critical assessment of the roentgenographic technique was made for a quantitative determination of bone and tail length in the rat. The method was found to be very reliable if error sources were controlled and minimized. The early and long term effects of x irradiation on skeletal growth were investigated with respect to the age at exposure. Rats exposed at a juvenile age (37 days) to a sublethal dose (430 rad) exhibited a retardation in femur, tibia, and tail growth within 14 days after exposure. The maximum deficit was attained within 30 days after exposure and remained approximately constant formore » the next 300 days. Femur and tibia length of animals which were exposed to x rays as young adults (101 days of age) did not differ from those of controls for the first two months after exposure. However, there was a deficit in femur and tibia length in these animals at the end of life span. The magnitude of the bone length reduction at the end of life span was dose dependent. The two major differences in response between the two age groups were the time course of the radiation effect on growth and the magnitude of the deficit. The reduction in bone length occurred faster and was greater in the younger irradiated group. (auth)« less
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Higuti, Eliza; Cecchi, Cláudia R; Oliveira, Nélio A J; Lima, Eliana R; Vieira, Daniel P; Aagaard, Lars; Jensen, Thomas G; Jorge, Alexander A L; Bartolini, Paolo; Peroni, Cibele N
2016-02-01
Non-viral transfer of the growth hormone gene to different muscles of immunodeficient dwarf (lit/scid) mice is under study with the objective of improving phenotypic correction via this particular gene therapy approach. Plasmid DNA was administered into the exposed quadriceps or non-exposed tibialis cranialis muscle of lit/scid mice followed by electroporation, monitoring several growth parameters. In a 6-month bioassay, 50μg DNA were injected three times into the quadriceps muscle of 80-day old mice. A 50% weight increase, with a catch-up growth of 21%, together with a 16% increase for nose-to-tail and tail lengths (catch-up=19-21%) and a 24-28% increase for femur length (catch-up=53-60%), were obtained. mIGF1 serum levels were ~7-fold higher than the basal levels for untreated mice, but still ~2-fold lower than in non-dwarf scid mice. Since treatment age was found to be particularly important in a second bioassay utilizing 40-day old mice, these pubertal mice were compared in a third bioassay with adult (80-day old) mice, all treated twice with 50μg DNA injected into each tibialis cranialis muscle, via a less invasive approach. mIGF1 concentrations at the same level as co-aged scid mice were obtained 15days after administration in pubertal mice. Catch-up growth, based on femur length (77%), nose-to-tail (36%) and tail length (39%) increases was 40 to 95% higher than those obtained upon treating adult mice. These data pave the way for the development of more effective pre-clinical assays in pubertal dwarf mice for the treatment of GH deficiency via plasmid-DNA muscular administration. Copyright © 2015 Elsevier Ltd. All rights reserved.
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NASA Technical Reports Server (NTRS)
Riebe, John M; Naeseth, Rodger L
1952-01-01
An investigation was made in the Langley 300-mph 7- by 10-foot tunnel to determine the aerodynamic characteristics of a refined deep-step planing-tail hull with various forebody and afterbody shapes and, for comparison, a streamline body simulating the fuselage of a modern transport airplane. The results of the tests indicated that the configurations incorporating a forebody with a length-beam ratio of 7 had lower minimum drag coefficients than the configurations incorporating a forebody with length-beam ratio of 5. The lowest minimum drag coefficients, which were considerably less than that of a conventional hull and slightly less than that of a streamline body, were obtained on the length-beam-ratio-7 forebody, alone and with round center boom. Drag coefficients and longitudinal- and lateral-stability parameters presented include the interference of a 21-percent-thick support wing.
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Large-amplitude jumps and non-Gaussian dynamics in highly concentrated hard sphere fluids.
Saltzman, Erica J; Schweizer, Kenneth S
2008-05-01
Our microscopic stochastic nonlinear Langevin equation theory of activated dynamics has been employed to study the real-space van Hove function of dense hard sphere fluids and suspensions. At very short times, the van Hove function is a narrow Gaussian. At sufficiently high volume fractions, such that the entropic barrier to relaxation is greater than the thermal energy, its functional form evolves with time to include a rapidly decaying component at small displacements and a long-range exponential tail. The "jump" or decay length scale associated with the tail increases with time (or particle root-mean-square displacement) at fixed volume fraction, and with volume fraction at the mean alpha relaxation time. The jump length at the alpha relaxation time is predicted to be proportional to a measure of the decoupling of self-diffusion and structural relaxation. At long times corresponding to mean displacements of order a particle diameter, the volume fraction dependence of the decay length disappears. A good superposition of the exponential tail feature based on the jump length as a scaling variable is predicted at high volume fractions. Overall, the theoretical results are in good accord with recent simulations and experiments. The basic aspects of the theory are also compared with a classic jump model and a dynamically facilitated continuous time random-walk model. Decoupling of the time scales of different parts of the relaxation process predicted by the theory is qualitatively similar to facilitated dynamics models based on the concept of persistence and exchange times if the elementary event is assumed to be associated with transport on a length scale significantly smaller than the particle size.
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An Assessment of the Length and Variability of Mercury's Magnetotail
NASA Technical Reports Server (NTRS)
Milan, S. E.; Slavin, J. A.
2011-01-01
We employ Mariner 10 measurements of the interplanetary magnetic field in the vicinity of Mercury to estimate the rate of magnetic reconnection between the interplanetary magnetic field and the Hermean magnetosphere. We derive a time-series of the open magnetic flux in Mercury's magnetosphere. from which we can deduce the length of the magnetotail The length of the magnetotail is shown to be highly variable. with open field lines stretching between 15R(sub H) and 8S0R(sub H) downstream of the planet (median 150R(sub H)). Scaling laws allow the tail length at perihelion to be deduced from the aphelion Mariner 10 observations.
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Jadejaroen, Janya; Hamada, Yuzuru; Kawamoto, Yoshi; Malaivijitnond, Suchinda
2015-01-01
Rhesus (Macaca mulatta) and long-tailed (M. fascicularis) macaques are the most commonly used non-human primate models for biomedical research, but it is difficult to identify these two species in the hybrid zone (15-20°N). In this work, we used morphological values obtained via photogrammetry to assess hybrids of rhesus and long-tailed macaques at Khao Khieow Open Zoo (KKZ; 13°21'N, 101°06'E), eastern Thailand. Long-tailed and rhesus macaques have species-specific tail lengths and contrasts of their yellowish pelages. The accuracy and precision of the relative tail length (%RTL) and the contrast of the yellow hue (Cb*) of the pelage, as obtained from photographs, were compared with the corresponding direct measurements (morphometrics). The photogrammetric and morphometric measurements of %RTL and Cb* were highly significantly correlated (r = 0.989 and 0.980, p < 0.001), and there were no significant differences between the two datasets (t test, p = 0.13 and 0.41; n = 42 and 17 for %RTL and Cb*, respectively). The reproducibilities of the %RTL and Cb* measurements (calculated in the photogrammetric case by taking photographs of the same macaques in two different environments) were significantly correlated between the datasets (r = 0.983 and 0.914, p < 0.001 and 0.005), and there were no significant differences between the datasets (t test, p = 0.539 and 0.344; n = 30 each for %RTL and Cb*, respectively). The %RTL and Cb* data were combined with data on the crown and cheek hair patterns and sex skin reddening of the macaques, and this combined data set was then analyzed by multiple correspondence analysis and agglomerative hierarchical cluster analysis, leading to the categorization of the rhesus macaques, long-tailed macaques, and hybrids at KKZ into five groups. Thus, photogrammetry can be utilized to identify macaque species or hybrids when species identification relies mainly on tail length and pelage color.
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DNA damage in human germ cell exposed to the some food additives in vitro.
Pandir, Dilek
2016-08-01
The use of food additives has increased enormously in modern food technology but they have adverse effects in human healthy. The aim of this study was to investigate the DNA damage of some food additives such as citric acid (CA), benzoic acid (BA), brilliant blue (BB) and sunset yellow (SY) which were investigated in human male germ cells using comet assay. The sperm cells were incubated with different concentrations of these food additives (50, 100, 200 and 500 μg/mL) for 1 h at 32 °C. The results showed for CA, BA, BB and SY a dose dependent increase in tail DNA%, tail length and tail moment in human sperm when compared to control group. When control values were compared in the studied parameters in the treatment concentrations, SY was found to exhibit the highest level of DNA damage followed by BB > BA > CA. However, none of the food additives affected the tail DNA%, tail length and tail moment at 50 and 100 μg/mL. At 200 μg/mL of SY, the tail DNA% and tail length of sperm were 95.80 ± 0.28 and 42.56 ± 4.66, for BB the values were 95.06 ± 2.30 and 39.56 ± 3.78, whereas for BA the values were 89.05 ± 2.78 and 31.50 ± 0.71, for CA the values were 88.59 ± 6.45 and 13.59 ± 2.74, respectively. However, only the highest concentration of the used food additives significantly affected the studied parameters of sperm DNA. The present results indicate that SY and BB are more harmful than BA and CA to human sperm in vitro.
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29 CFR 1926.251 - Rigging equipment for material handling.
Code of Federal Regulations, 2012 CFR
2012-07-01
... splices, the U-bolt shall be applied so that the “U” section is in contact with the dead end of the rope... laid grommets and endless slings shall have a minimum circumferential length of 96 times their body... body of the rope using at least two additional tucks (which will require a tail length of approximately...
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30 CFR 56.19021 - Minimum rope strength.
Code of Federal Regulations, 2010 CFR
2010-07-01
...=Static Load×4.0 (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0-0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0 (c) Tail ropes....19021 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL...
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30 CFR 57.19021 - Minimum rope strength.
Code of Federal Regulations, 2011 CFR
2011-07-01
...=Static Load×4.0. (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0−0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0. (c) Tail....19021 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL...
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30 CFR 57.19021 - Minimum rope strength.
Code of Federal Regulations, 2010 CFR
2010-07-01
...=Static Load×4.0. (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0−0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0. (c) Tail....19021 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL...
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30 CFR 56.19021 - Minimum rope strength.
Code of Federal Regulations, 2011 CFR
2011-07-01
...=Static Load×4.0 (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0-0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0 (c) Tail ropes....19021 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL...
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Akdag, Mehmet; Dasdag, Suleyman; Canturk, Fazile; Akdag, Mehmet Zulkuf
2018-01-01
The aim of this study was to investigate effect of radiofrequency radiation (RFR) emitted from mobile phones on DNA damage in follicle cells of hair in the ear canal. The study was carried out on 56 men (age range: 30-60 years old)in four treatment groups with n = 14 in each group. The groups were defined as follows: people who did not use a mobile phone (Control), people use mobile phones for 0-30 min/day (second group), people use mobile phones for 30-60 min/day (third group) and people use mobile phones for more than 60 min/day (fourth group). Ear canal hair follicle cells taken from the subjects were analyzed by the Comet Assay to determine DNA damages. The Comet Assay parameters measured were head length, tail length, comet length, percentage of head DNA, tail DNA percentage, tail moment, and Olive tail moment. Results of the study showed that DNA damage indicators were higher in the RFR exposure groups than in the control subjects. In addition, DNA damage increased with the daily duration of exposure. In conclusion, RFR emitted from mobile phones has a potential to produce DNA damage in follicle cells of hair in the ear canal. Therefore, mobile phone users have to pay more attention when using wireless phones.
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The ultimate and proximate mechanisms driving the evolution of long tails in forest deer mice.
Kingsley, Evan P; Kozak, Krzysztof M; Pfeifer, Susanne P; Yang, Dou-Shuan; Hoekstra, Hopi E
2017-02-01
Understanding both the role of selection in driving phenotypic change and its underlying genetic basis remain major challenges in evolutionary biology. Here, we use modern tools to revisit a classic system of local adaptation in the North American deer mouse, Peromyscus maniculatus, which occupies two main habitat types: prairie and forest. Using historical collections, we find that forest-dwelling mice have longer tails than those from nonforested habitat, even when we account for individual and population relatedness. Using genome-wide SNP data, we show that mice from forested habitats in the eastern and western parts of their range form separate clades, suggesting that increased tail length evolved independently. We find that forest mice in the east and west have both more and longer caudal vertebrae, but not trunk vertebrae, than nearby prairie forms. By intercrossing prairie and forest mice, we show that the number and length of caudal vertebrae are not correlated in this recombinant population, indicating that variation in these traits is controlled by separate genetic loci. Together, these results demonstrate convergent evolution of the long-tailed forest phenotype through two distinct genetic mechanisms, affecting number and length of vertebrae, and suggest that these morphological changes-either independently or together-are adaptive. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.
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Dynamic and mechanical properties of supported lipid bilayers
NASA Astrophysics Data System (ADS)
Wu, Hsing-Lun; Tsao, Heng-Kwong; Sheng, Yu-Jane
2016-04-01
Supported lipid bilayers (SLBs) offer an excellent model system for investigating the physico-chemical properties of the cell membrane. In this work, dynamic and mechanical properties of SLBs are explored by dissipative particle dynamics simulations for lipids with different architectures (chain length, kink, and asymmetry associated with lipid tails). It is found that the lateral diffusivity (Dx) and flip-flop rate (FF) grow with increasing temperature in both gel and liquid phases and can be described by an Arrhenius-like expression. Three regimes can be clearly identified for symmetric and asymmetric saturated lipids but only two regimes are observed for kinked lipids. Both Dx and FF grow with decreasing tail length and increasing number of kinks. The stretching (KA) and apparent bending (KB) moduli exhibit concave upward curves with temperature and the minima are attained at Tm. In general, the minima of KA and KB decrease with the chain length and increase with number of kinks. The typical relation among the bending modulus, area stretching modulus, and bilayer thickness is still followed, KB = βKAh2 and β is much smaller in the gel phase. The dynamic and mechanical properties of lipids with asymmetric tails are found to situate between their symmetric counterparts.
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Fuss, Theodora; Bleckmann, Horst; Schluessel, Vera
2014-01-01
Bamboo sharks (Chiloscyllium griseum) were tested for their ability to perceive subjective and illusionary contours as well as line length illusions. Individuals were first trained to differentiate between squares, triangles, and rhomboids in a series of two alternative forced-choice experiments. Transfer tests then elucidated whether Kanizsa squares and triangles, grating gaps and phase shifted abutting gratings were also perceived and distinguished. The visual systems of most vertebrates and even invertebrates perceive illusionary contours despite the absence of physical luminance, color or textural differences. Sharks are no exception to the rule; all tasks were successfully mastered within 3–24 training sessions, with sharks discriminating between various sets of Kanizsa figures and alternative stimuli, as well as between subjective contours in >75% of all tests. However, in contrast to Kanizsa figures and subjective contours, sharks were not deceived by Müller-Lyer (ML) illusions. Here, two center lines of equal length are comparatively set between two arrowheads or –tails, in which case the line featuring the two arrow tails appears to be longer to most humans, primates and birds. In preparation for this experiment, lines of varying length, and lines of unequal length randomly featuring either two arrowheads or -tails on their ends, were presented first. Both sets of lines were successfully distinguished by most sharks. However, during presentation of the ML illusions sharks failed to succeed and succumbed either to side preferences or chose according to chance. PMID:24688458
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Fuss, Theodora; Bleckmann, Horst; Schluessel, Vera
2014-01-01
Bamboo sharks (Chiloscyllium griseum) were tested for their ability to perceive subjective and illusionary contours as well as line length illusions. Individuals were first trained to differentiate between squares, triangles, and rhomboids in a series of two alternative forced-choice experiments. Transfer tests then elucidated whether Kanizsa squares and triangles, grating gaps and phase shifted abutting gratings were also perceived and distinguished. The visual systems of most vertebrates and even invertebrates perceive illusionary contours despite the absence of physical luminance, color or textural differences. Sharks are no exception to the rule; all tasks were successfully mastered within 3-24 training sessions, with sharks discriminating between various sets of Kanizsa figures and alternative stimuli, as well as between subjective contours in >75% of all tests. However, in contrast to Kanizsa figures and subjective contours, sharks were not deceived by Müller-Lyer (ML) illusions. Here, two center lines of equal length are comparatively set between two arrowheads or -tails, in which case the line featuring the two arrow tails appears to be longer to most humans, primates and birds. In preparation for this experiment, lines of varying length, and lines of unequal length randomly featuring either two arrowheads or -tails on their ends, were presented first. Both sets of lines were successfully distinguished by most sharks. However, during presentation of the ML illusions sharks failed to succeed and succumbed either to side preferences or chose according to chance.
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Mechanics, morphology, and mobility in stratum corneum membranes
NASA Astrophysics Data System (ADS)
Olmsted, Peter; Das, Chinmay; Noro, Massimo
2012-02-01
The stratum corneum is the outermost layer of skin, and serves as a protective barrier against external agents, and to control moisture. It comprises keratin bodies (corneocytes) embedded in a matrix of lipid bilayers. Unlike the more widely studied phospholipid bilayers, the SC bilayers are typically in a gel-like state. Moreover, the SC membrane composition is radically different from more fluid counterparts: it comprises single tailed fatty acids, ceramides, and cholesterol; with many distinct ceramides possessing different lengths of tails, and always with two tails of different lengths. I will present insight from computer simulations into the morphology, mechanical properties, and diffusion (barrier) properties of these highly heterogeneous membranes. Our results provide some clue as to the design principles for the SC membrane, and is an excellent example of the use of wide polydispersity by natural systems.
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Estimated areal extent of colonies of black-tailed prairie dogs in the northern Great Plains
Sidle, John G.; Johnson, Douglas H.; Euliss, Betty R.
2001-01-01
During 1997–1998, we undertook an aerial survey, with an aerial line-intercept technique, to estimate the extent of colonies of black-tailed prairie dogs (Cynomys ludovicianus) in the northern Great Plains states of Nebraska, North Dakota, South Dakota, and Wyoming. We stratified the survey based on knowledge of colony locations, computed 2 types of estimates for each stratum, and combined ratio estimates for high-density strata with average density estimates for low-density strata. Estimates of colony areas for black-tailed prairie dogs were derived from the average percentages of lines intercepting prairie dog colonies and ratio estimators. We selected the best estimator based on the correlation between length of transect line and length of intercepted colonies. Active colonies of black-tailed prairie dogs occupied 2,377.8 km2 ± 186.4 SE, whereas inactive colonies occupied 560.4 ± 89.2 km2. These data represent the 1st quantitative assessment of black-tailed prairie dog colonies in the northern Great Plains. The survey dispels popular notions that millions of hectares of colonies of black-tailed prairie dogs exist in the northern Great Plains and can form the basis for future survey efforts.
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Sharma, Bibek; Patino, R.
2008-01-01
Xenopus laevis were exposed to 0-855 ??g cadmium (Cd)/l (measured concentrations) in FETAX medium from fertilization to 47 days postfertilization. Measurements included embryonic survival and, at 47 days, tadpole survival, snout-vent length, tail length, total length, hindlimb length, weight, Nieuwkoop-Faber (NF) stage of development, initiation of metamorphic climax (??? NF 58), and thyroid follicle cell height. Embryonic and larval survival were unaffected by Cd. Relative to control tadpoles, reduced tail and total length were observed at 0.1- 8 and at 855 ??g Cd/l; and reduced snout-vent length, hindlimb length, and weight were observed at 0.1-1 and at 855 ??g Cd/l. Mean stage of development and rate of initiation of climax were unaffected by Cd at 0-84 ??g/l; however, none of the tadpoles exposed to 855 ??g Cd/l progressed beyond mid-premetamorphosis (NF 51). Thyroid glands with fully formed follicles were observed in all tadpoles ??? NF 49 examined. Follicle cell height was unaffected by Cd at 0-84 ??g/l but it was reduced at 855 ??g/l; in the latter, cell height was reduced even when compared with NF 49-51 tadpoles pooled from the 0 to 84 ??g Cd/l groups. In conclusion, (1) Cd affected tadpole growth in a bimodal pattern with the first and second inhibitory modes at concentrations below and above 84 ??g Cd/l, respectively; (2) exposure to high Cd concentrations (855 ??g/l) reduced thyroid activity and arrested tadpole development at mid-premetamorphosis; and (3) unlike its effect on growth, Cd inhibited tadpole development and thyroid function in a seemingly monotonic pattern.
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30 CFR 77.1431 - Minimum rope strength.
Code of Federal Regulations, 2011 CFR
2011-07-01
...=Static Load×4.0 (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0−0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0 (c) Tail ropes... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH...
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30 CFR 77.1431 - Minimum rope strength.
Code of Federal Regulations, 2010 CFR
2010-07-01
...=Static Load×4.0 (b) Friction drum ropes. For rope lengths less than 4,000 feet: Minimum Value=Static Load×(7.0−0.0005L) For rope lengths 4,000 feet or greater: Minimum Value=Static Load×5.0 (c) Tail ropes... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH...
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Of Mice and Snakes: A Tail of Oct4.
Shylo, Natalia A; Weatherbee, Scott D
2016-08-08
The vertebrate axial skeleton comprises regions of specialized vertebrae, which vary in length between lineages. Aires et al. (2016) uncover a key role for Oct4 in determining trunk length in mice. Additionally, a heterochronic shift in Oct4 expression may underlie the extreme elongation of the trunk in snakes. Copyright © 2016 Elsevier Inc. All rights reserved.
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Varieties of charge distributions in coat proteins of ssRNA+ viruses
NASA Astrophysics Data System (ADS)
Lošdorfer Božič, Anže; Podgornik, Rudolf
2018-01-01
A major part of the interactions involved in the assembly and stability of icosahedral, positive-sense single-stranded RNA (ssRNA+) viruses is electrostatic in nature, as can be inferred from the strong pH- and salt-dependence of their assembly phase diagrams. Electrostatic interactions do not act only between the capsid coat proteins (CPs), but just as often provide a significant contribution to the interactions of the CPs with the genomic RNA, mediated to a large extent by positively charged, flexible N-terminal tails of the CPs. In this work, we provide two clear and complementary definitions of an N-terminal tail of a protein, and use them to extract the tail sequences of a large number of CPs of ssRNA+ viruses. We examine the pH-dependent interplay of charge on both tails and CPs alike, and show that—in contrast to the charge on the CPs—the net positive charge on the N-tails persists even to very basic pH values. In addition, we note a limit to the length of the wild-type genomes of those viruses which utilize positively charged tails, when compared to viruses without charged tails and similar capsid size. At the same time, we observe no clear connection between the charge on the N-tails and the genome lengths of the viruses included in our study.
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Sundari, J; Selvaraj, R; Rajendra Prasad, N; Elumalai, R
2013-11-01
The present study is conducted to investigate the antioxidant potential of Jatropha curcas root bark extract (RB4 fraction) and leaf extract (L1 fraction), and to study their effects on UVB-radiation-induced DNA damage in cultured human blood lymphocytes. In this study, J. curcas showed strong antioxidant property in different free radical scavenging systems. Both the fractions effectively scavenged hydroxyl (OH), superoxide anion (O₂(·-)), 1,1-diphenyl-2-picrylhydrazyl (DPPH·) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid radical cation (ABTS(·+)) in a concentration-dependent manner. The IC₅₀ (Inhibitory Concentration 50) values of J. curcas fractions were compared to standard ascorbic acid used in this study. The antioxidant potential of a compound was directly proportional to the photoprotective effect. In this study, human peripheral blood lymphocytes (HPBL) were exposed to UVB-radiation and there was an increase in comet attributes (% tail DNA, tail length, tail movement and Olive tail moment). Jatropha curcas RB4 fraction and L1 fraction treatment before UVB-irradiation significantly decreased the % tail DNA, tail length, tail moment and Olive tail moment in irradiated HPBL. These results suggested that J. curcas exhibited strong antioxidant property and RB4 and L1 fractions protected UVB-radiation-induced DNA damage in HPBL. Copyright © 2013 Elsevier B.V. All rights reserved.
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1973-12-14
S73-38390 (6 Dec. 1973) --- An Earth-based photograph of the Comet Kohoutek in the sky on Dec. 6, 1973, when the celestial phenomenon was more than 70 million miles from the sun and some 119 million miles from Earth. This picture was taken from a dark mountain top area of Haleakala (Island of Maui) Hawaii, using a 35mm Nikon camera with a 55mm lens, a 300-second exposure at f/1.2 and with Tri-X film. The photographer was Frank Giovane. The indicated visible tail of the comet appears to be about 10 million miles long. Other reports have inferred that the length of the tail is up to 13 million miles. The Skylab 4 crewmen have reported that Kohoutek's tail-length was from two to three degrees or from four to six million miles as viewed with the naked eye from the Skylab space station in Earth orbit. Photo credit: NASA/Frank Giovane
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NASA Astrophysics Data System (ADS)
Serva, A.; Migliorati, V.; Lapi, A.; D'Angelo, P.
2016-05-01
The structural properties of geminal dicationic ionic liquids ([Cn (mim)2]Br2)/water mixtures have been investigated by means of extended X-ray absorption fine structure (EXAFS) spectroscopy and Molecular Dynamics (MD) simulations. This synergic approach allowed us to assess the reliability of the MD results and to provide accurate structural information about the first coordination shell of the Br- ion. We found that the local environment around the anion changes as a function of the water concentration, while it is the same independently from the length of the bridge-alkyl chain. Moreover, as regards the long-range structural organization, no tail-tail aggregation occurs with increasing alkyl chain length.
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Arima, Hiroshi; Morishita, Yoshiaki; Hagiwara, Daisuke; Hayashi, Masayuki; Oiso, Yutaka
2014-01-01
The immunoglobulin heavy chain binding protein (BiP) is an endoplasmic reticulum (ER) chaperone, which binds to newly synthesized secretory and transmembrane proteins to facilitate protein folding. BiP mRNA is expressed in the arginine vasopressin (AVP) neurons in the supraoptic nucleus of wild-type mice even in basal conditions, and the expression levels increase in response to dehydration. These data suggest that AVP neurons are subjected to ER stress. Familial neurohypophysial diabetes insipidus (FNDI) is caused by mutations in the gene locus of AVP. The mutant proteins could accumulate in the ER and possibly increase ER stress in the AVP neurons. We bred mice possessing a mutation causing FNDI, which manifested progressive polyuria, as do the patients with FNDI. Electron microscopic analyses demonstrated that aggregates accumulated in the ER of AVP neurons in FNDI mice. Despite polyuria, which could potentially induce dehydration, AVP mRNA expression was decreased in the supraoptic nucleus, and the AVP mRNA poly(A) tail length was shortened in FNDI mice compared with wild-type mice. Incubation of hypothalamic explants of wild-type mice with ER stressors caused shortening of the poly(A) tail length of AVP mRNA, accompanied by decreases in the expression. These data revealed a mechanism by which ER stress decreases poly(A) tail length of AVP mRNA, and this reduces the load of unfolded proteins that form the aggregates in ER of the AVP neurons in FNDI mice.
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Three new Procamallanus (Spirocamallanus) species from freshwater fishes in Mexico.
Moravec, F; Salgado-Maldonado, G; Caspeta-Mandujano, J
2000-02-01
The following 3 new species of Procamallanus (Spirocamallanus) are described from the intestines of freshwater fishes in Mexico, all belonging to the morphological group characterized by the presence of wide caudal alae, 3 pairs of subventral preanal papillae, and unequal spicules in the male: Procamallanus (Spirocamallanus) jaliscensis n. sp. (type host: Agonostomus monticola) and Procamallanus (Spirocamallanus) gobiomori n. sp. (hosts: Gobiomorus maculatus [type host], Gobiomorus polylepis and Eleotris picta) from 2 rivers in Jalisco State, western Mexico, and Procamallanus (Spirocamallanus) mexicanus n. sp. (type host: Cichlasoma geddesi) from Xalapa District, Veracruz State (Gulf of Mexico region), southeastern Mexico. Procamallanus jaliscensis is characterized by the length of the spicules (606-900 microm and 282-354 microm), number (15-16) of spiral ridges in the buccal capsule, and the digit-like protrusion with 1 terminal cuticular spike on the female tail; P. mexicanus by the length of the spicules (456-480 microm and 231-233 microm), number (10-12) of spiral ridges in the capsule, and the shape of the female tail (conical with a suddenly narrowed distal part, without any terminal spikes); and P. gobiomori by the length of spicules (318-348 microm and 156-192 microm), number (8-10) of spiral ridges and by the digit-like protrusion with 2 terminal cuticular spikes on the female tail.
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West, Ana; Ma, Kevin; Chung, Jonathan L; Kindt, James T
2013-08-15
Molecular dynamics simulations of lipid bilayer ribbons have been performed to investigate the structures and line tensions associated with free bilayer edges. Simulations carried out for dioleoyl phosphatidylcholine with three different force-field parameter sets yielded edge line tensions of 45 ± 2 pN, over 50% greater than the most recently reported experimentally determined value for this lipid. Edge tensions obtained from simulations of a series of phosphatidylcholine lipid bilayer ribbons with saturated acyl tails of length 12-16 carbons and with monounsaturated acyl tails of length 14-18 carbons could be correlated with the excess area associated with forming the edge, through a two-parameter fit. Saturated-tail lipids underwent local thickening near the edge, producing denser packing that correlated with lower line tensions, while unsaturated-tail lipids showed little or no local thickening. In a dipalmitoyl phosphatidylcholine ribbon initiated in a tilted gel-phase structure, lipid headgroups tended to tilt toward the nearer edge producing a herringbone pattern, an accommodation that may account for the reported edge-induced stabilization of an ordered structure at temperatures near a lipid gel-fluid phase transition.
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NASA Technical Reports Server (NTRS)
Axelson, John A.; Crown, J. Conrad
1948-01-01
An analysis is presented of the influence of wing aspect ratio and tail location on the effects of compressibility upon static longitudinal stability. The investigation showed that the use of reduced wing aspect ratios or short tail lengths leads to serious reductions in high-speed stability and the possibility of high-speed instability.
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Morphological and molecular characterization of Globodera populations from Oregon and Idaho.
Skantar, A M; Handoo, Z A; Zasada, I A; Ingham, R E; Carta, L K; Chitwood, D J
2011-04-01
An unusual population of cyst nematode was found in soils collected from a Powell Butte, OR field with a cropping history including potato, wheat, other crops, and significant weed presence. These nematodes could not be placed with certainty into any known species and exhibited some unique morphological features in some specimens. Compared with Globodera pallida, the cyst body length was slightly longer and the second-stage juvenile stylet length was slightly shorter. In some individuals, the J2 stylet knob height was greater and the tail annules were more prominent than in G. pallida, and the tail abruptly narrowed, with a slight constriction near the posterior third of the hyaline terminus. Compared with G. rostochiensis, the hyaline tail terminus had a larger number of refractive bodies, and cysts of this population had a smaller Granek's ratio and fewer cuticular ridges between the anus and vulva. In some individuals, the tail termini of second-stage juveniles were more bluntly pointed, and the stylet knobs were more anteriorly directed with greater height. Unlike G. tabacum, the cyst wall often lacked a network-like pattern and, in some individuals, the juvenile tail terminus distinctly narrowed after a constriction. Molecularly, the population was distinct from G. pallida, G. rostochiensis, and G. tabacum. Multiplex polymerase chain reaction of the internal transcribed spacer (ITS) rDNA region gave results similar to G. tabacum; however, ITS restriction fragment length polymorphism patterns were observed to have individual bands in common with G. rostochiensis and G. pallida. Phylogenetic analysis based on ITS1 and -2 rDNA sequences showed greatest similarity to populations from Argentina and Chile; together, they form a moderately supported clade, distinct from G. rostochiensis, G. tabacum, G. "mexicana," European type G. pallida, and several G. pallida populations from South America.
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Use of optimization to predict the effect of selected parameters on commuter aircraft performance
NASA Technical Reports Server (NTRS)
Wells, V. L.; Shevell, R. S.
1982-01-01
An optimizing computer program determined the turboprop aircraft with lowest direct operating cost for various sets of cruise speed and field length constraints. External variables included wing area, wing aspect ratio and engine sea level static horsepower; tail sizes, climb speed and cruise altitude were varied within the function evaluation program. Direct operating cost was minimized for a 150 n.mi typical mission. Generally, DOC increased with increasing speed and decreasing field length but not by a large amount. Ride roughness, however, increased considerably as speed became higher and field length became shorter.
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Levsen, Arne; Berland, Bjørn
2002-01-01
In this paper, the quantitative post-embryonic development of the Asian freshwater fish nematode Camallanus cotti Fujita, 1927, is described. Larval and adult morphometrics were obtained by following the parasite's life cycle experimentally using copepods Macrocyclops albidus (Jurine) as intermediate host and guppies Poecilia reticulata (Peters), southern platyfish Xiphophorus maculatus (Günther) and paradise fish Macropodus opercularis (L.) as definitive host. Additionally, adult worms were obtained from heavily infected paradise fish imported from Singapore. It is suggested that the gradual change in proportions of the worm's somatic body parts reflects the specific ecological role of each developmental stage. The free-living infective first-stage larva seems to be adapted for transmission, as indicated by its relatively long tail, designed to generate host-attracting movements, and its non-functional intestine. The second- and third-stage larvae from the copepod intermediate host seem mainly to invest in trophic functionality, i.e., the development of the buccal capsule and the oesophagus, which are crucial structures for the worm's successful establishment in the definitive fish host. Once in the fish intestine, the larvae enter a period of considerable growth. After the fourth (i.e., last) moult, a 72% increase in average female body length occurs. This is accompanied by doubling the average vulva-tail tip distance and the average tail length. The length of the female hind body expands in an accelerating allometric fashion, and seems to be closely linked to the posterior-wards expansion of the uterus. In the males however, growth seems to cease after the final moult. We conclude that female post-maturational body size, but especially the length of the hind body and the tail, are closely related to reproductive state, i.e., the developmental stage of the offspring in the uterus, and, probably, the worms' age. Any future taxonomical studies of camallanids in general, and C. cotti in particular, should thus be aware of the reproductive state of the females used.
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Molecular simulations of lipid systems: Edge stability and structure in pure and mixed bilayers
NASA Astrophysics Data System (ADS)
Jiang, Yong
2007-12-01
Understanding the structural, mechanical and dynamical properties of lipid self-assembled systems is fundamental to understand the behavior of the cell membrane. This thesis has investigated the equilibrium properties of lipid systems with edge defects through various molecular simulation techniques. The overall goal of this study is to understand the free energy terms of the edges and to develop efficient methods to sample equilibrium distributions of mixed-lipid systems. In the first main part of my thesis, an atomistic molecular model is used to study lipid ribbon which has two edges on both sides. Details of the edge structures, such as area per lipid and tail torsional statistics are presented. Line tension, calculated from pressure tensor in MD simulation has good agreement with result from other sources. To further investigate edge properties on a longer timescale and larger length scale, we have applied a coarse-grained forcefield on mixed lipid systems and try to interpret the edge fluctuations in terms of free energy parameters such as line tension and bending modulus. We have identified two regimes with quite different edge behavior: a high line tension regime and a low line tension regime. The last part of this thesis focuses on a hybrid Molecular dynamics and Configurational-bias Monte Carlo (MCMD) simulation method in which molecules can change their type by growing and shrinking the terminal acyl united carbon atoms. A two-step extension of the MCMD method has been developed to allow for a larger difference in the components' tail lengths. Results agreed well with previous one-step mutation results for a mixture with a length difference of four carbons. The current method can efficiently sample mixtures with a length difference of eight carbons, with a small portion of lipids of intermediate tail length. Preliminary results are obtained for "bicelle"-type (DMPC/DHPC) ribbons.
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NASA Technical Reports Server (NTRS)
Dawson, John R; Mckann, Robert; Hay, Elizabeth S
1946-01-01
The second part of a series of tests made in Langley tank no. 2 to determine the effect of varying design parameters of planing-tail hulls is presented. Results are given to show the effects on resistance characteristics of varying angle of afterbody keel, depth of step, and length of afterbody chine. The effect of varying the gross load is shown for one configuration. The resistance characteristics of planing-tail hulls are compared with those of a conventional flying-boat hull. The forces on the forebody and afterbody of one configuration are compared with the forces on a conventional hull. Increasing the angle of afterbody keel had small effect on hump resistance and no effect on high-speed resistance but increased free-to-trim resistance at intermediate speeds. Increasing the depth of step increased hump resistance, had little effect on high-speed resistance, and increased free-to-trim resistance at intermediate speeds. Omitting the chines on the forward 25 percent of the afterbody had no appreciable effect on resistance. Omitting 70 percent of the chine length had almost no effect on maximum resistance but broadened the hump and increased spray around the afterbody. Load-resistance ratio at the hump decreased more rapidly with increasing load coefficient for the planing-tail hull than for the representative conventional hull, although the load-resistance ratio at the hump was greater for the planing-tail hull than for the conventional hull throughout the range of loads tested. At speeds higher than hump speed, load-resistance ratio for the planing-tail hull was a maximum at a particular gross load and was slightly less at heavier and lighter gross loads. The planing-tail hull was found to have lower resistance than the conventional hull at both the hump and at high speeds, but at intermediate speeds there was little difference. The lower hump resistance of the planing-tail hull was attributed to the ability of the afterbody to carry a greater percentage of the total load while maintaining a higher value of load-resistance ratio.
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The Comet Halley Handbook: An Observer's Guide. Second Edition.
ERIC Educational Resources Information Center
Yeomans, Donald K.
This handbook contains information on: (1) the orbit of comet Halley; (2) the expected physical behavior of comet Halley in 1985-1986, considering brightness estimates, coma diameters, and tail lengths; (3) observing conditions for comet Halley in 1985-1986; and (4) observing conditions for the dust tail of comet Halley in 1985-1986. Additional…
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Sharma, Manisha; Jamieson, Cara; Lui, Christina
β-catenin is a key mediator of Wnt signaling and its deregulated nuclear accumulation can drive cancer progression. While the central armadillo (Arm) repeats of β-catenin stimulate nuclear entry, the N- and C-terminal “tail” sequences are thought to regulate turnover and transactivation. We show here that the N- and C-tails are also potent transport sequences. The unstructured tails of β-catenin, when individually fused to a GFP-reporter, could enter and exit the nucleus rapidly in live cells. Proximity ligation assays and pull-down assays identified a weak interaction between the tail sequences and the FG-repeats of nucleoporins, consistent with a possible direct translocationmore » of β-catenin through the nuclear pore complex. Extensive alanine mutagenesis of the tail sequences revealed that nuclear translocation of β-catenin was dependent on specific uniformly distributed patches of hydrophobic residues, whereas the mutagenesis of acidic amino acids had no effect. Moreover, the mutation of hydrophobic patches within the N-tail and C-tail of full length β-catenin reduced nuclear transport rate and diminished its ability to activate transcription. We propose that the tail sequences can contribute to β-catenin transport and suggest a possible similar role for hydrophobic unstructured regions in other proteins. - Highlights: • We show that the N- and C-tails of beta-catenin possess nuclear transport activity. • Nuclear transport of the N- or C-tails requires specific hydrophobic amino acids. • Mutagenesis of the N-terminus diminished nuclear entry of full-length beta-catenin. • We propose the N-tail contributes to beta-catenin nuclear entry and transactivation.« less
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Masuda, Shuichi; Deguchi, Yuya; Masuda, Yumi; Watanabe, Tetsushi; Nukaya, Haruo; Terao, Yoshiyasu; Takamura, Takeji; Wakabayashi, Keiji; Kinae, Naohide
2004-05-09
2-[2-(Acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6) and 4-amino-3,3'-dichloro-5,4'-dinitrobiphenyl (ADDB) are two compounds, which show strong mutagenicity toward bacteria, that have been identified as major mutagens in river water in Japan. In the present study, we examined the genotoxicity of PBTA-6 and ADDB in goldfish (Carassius auratus) by the micronucleus test and single-cell gel electrophoresis (comet assay). The frequencies of micronuclei in gill cells gradually increased until 96h after i.p. injection of PBTA-6 and ADDB at doses of 50mg/kg body weight, and then decreased 144h after injection. PBTA-6 induced micronuclei in gill cells dose-dependently at a dose range of 1-100mg/kg body weight, giving significantly high frequencies at doses of 50 and 100mg/kg body weight. On the other hand, no significant increase was observed in the peripheral erythrocytes of goldfish exposed to PBTA-6 or ADDB. In the comet assay, values of DNA tail moment and tail length in peripheral erythrocytes increased significantly until 6h after the i.p. injection of PBTA-6 (50mg/kg body weight), only to decrease by 9h after injection. Both the DNA tail moment and tail length were dose-dependently increased by injections of PBTA-6 at doses ranging from 1 to 50mg/kg. Significantly high values for tail moment and tail length were found in peripheral erythrocytes 3h after an i.p. injection of ADDB and persisted for up to 6h. These results show that both PBTA-6 and ADDB have genotoxic effects in goldfish.
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A new species of smooth skink (Squamata: Scincidae: Scincella) from Cambodia.
Neang, Thy; Chan, Somaly; Poyarkov, Nikolay A
2018-05-18
Based on morphological and genetic evidence we evaluated the taxonomic status of a newly discovered forest-dwelling population of skink (genus Scincella) from the Keo Seima Wildlife Sanctuary, Mondulkiri Province, Cambodia. From phylogenetic analysis of a 668-bp fragment of the mtDNA COI and diagnostic morphological characters we allocate the newly discovered population to the Scincella reevesii-S. rufocaudata species complex and describe it as Scincella nigrofasciata sp. nov. The new skink species can be distinguished from all other Southeast Asian congeners by the following combination of morphological characters: snout-vent length (SVL) 40.0-52.6 mm; relative tail length (TaL/SVL ratio) 1.25-1.94; prefrontals in broad contact; infralabials 6; primary temporals 2; relative forelimb length (FIL/SVL ratio) 0.20-0.22; relative hindlimb length (HIL/SVL ratio) 0.30-0.33; relative forearm length (FoL/SVL ratio) 0.14-0.16; adpressed forelimbs and hind limbs either overlapping (0.4-2.2 mm) or separated (1.9-2.3 mm); midbody scale rows 32-33, paravertebral scales 69-74, vertebral scales 65-69; dorsal scales between dorsolateral stripes 8; comparatively slender fingers and toes, subdigital lamellae under fourth toe 15-17; dark discontinuous regular dorsal stripes 5-7; distinct black dorsolateral stripes, narrowing to lateral sides and extending to 52%-86% of total tail length. We provide additional information on the holotype of Scincella rufocaudata (Darevsky & Nguyen, 1983), and provide evidence for the species status of Scincella rupicola. Our discovery brings the number of Scincella species in Cambodia to five and emphasizes the incompleteness of knowledge on the herpetofaunal diversity of this country.
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Localization of soft modes at the depinning transition
NASA Astrophysics Data System (ADS)
Cao, Xiangyu; Bouzat, Sebastian; Kolton, Alejandro B.; Rosso, Alberto
2018-02-01
We characterize the soft modes of the dynamical matrix at the depinning transition, and compare the matrix with the properties of the Anderson model (and long-range generalizations). The density of states at the edge of the spectrum displays a universal linear tail, different from the Lifshitz tails. The eigenvectors are instead very similar in the two matrix ensembles. We focus on the ground state (soft mode), which represents the epicenter of avalanche instabilities. We expect it to be localized in all finite dimensions, and make a clear connection between its localization length and the Larkin length of the depinning model. In the fully connected model, we show that the weak-strong pinning transition coincides with a peculiar localization transition of the ground state.
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Li, Xueshu; Turánek, Jaroslav; Knötigová, Pavlína; Kudláčková, Hana; Mašek, Josef; Parkin, Sean; Rankin, Stephen E; Knutson, Barbara L; Lehmler, Hans-Joachim
2009-01-01
A series of hydrocarbon and fluorocarbon carbohydrate surfactants with different headgroups (i.e., gluco-, galacto- and maltopyranoside) and (fluorinated) alkyl tails (i.e., C7 and C14 to C19) was synthesized to investigate trends in their cytotoxicity and haemolytic activity, and how surfactant-lipid interactions of selected surfactants contribute to these two measures of biocompatibility. All surfactants displayed low cytotoxicity (EC50 = 25 to > 250 μM) and low haemolytic activity (EC50 = 0.2 to > 3.3 mM), with headgroup structure, tail length and degree of fluorination being important structural determinants for both endpoints. The EC50 values of hydrocarbon and fluorocarbon glucopyranoside surfactants displayed a “cut-off” effect (i.e., a maximum with respect to the chain length). According to steady-state fluorescence anisotropy studies, short chain (C7) surfactants partitioned less readily into model membranes, which explains their low cytotoxicity and haemolytic activity. Interestingly, galactopyranosides were less toxic compared to glucopyranosides with the same hydrophobic tail. Although both surfactant types only differ in the stereochemistry of the 4-OH group, hexadecyl gluco- and galactopyranoside surfactants had similar apparent membrane partition coefficients, but differed in their overall effect on the phase behaviour of DPPC model membranes, as assessed using steady-state fluorescence anisotropy studies. These observations suggest that highly selective surfactant-lipid interactions may be responsible for the differential cytotoxicity and, possible, haemolytic activity of hydrocarbon and fluorocarbon carbohydrate surfactants intended for a variety of pharmaceutical and biomedical applications. PMID:19481909
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Alternative splicing modulates Kv channel clustering through a molecular ball and chain mechanism
NASA Astrophysics Data System (ADS)
Zandany, Nitzan; Marciano, Shir; Magidovich, Elhanan; Frimerman, Teddy; Yehezkel, Rinat; Shem-Ad, Tzilhav; Lewin, Limor; Abdu, Uri; Orr, Irit; Yifrach, Ofer
2015-03-01
Ion channel clustering at the post-synaptic density serves a fundamental role in action potential generation and transmission. Here, we show that interaction between the Shaker Kv channel and the PSD-95 scaffold protein underlying channel clustering is modulated by the length of the intrinsically disordered C terminal channel tail. We further show that this tail functions as an entropic clock that times PSD-95 binding. We thus propose a ‘ball and chain’ mechanism to explain Kv channel binding to scaffold proteins, analogous to the mechanism describing channel fast inactivation. The physiological relevance of this mechanism is demonstrated in that alternative splicing of the Shaker channel gene to produce variants of distinct tail lengths resulted in differential channel cell surface expression levels and clustering metrics that correlate with differences in affinity of the variants for PSD-95. We suggest that modulating channel clustering by specific spatial-temporal spliced variant targeting serves a fundamental role in nervous system development and tuning.
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Leucocytes DNA damage in mice exposed to JS-118 by the comet assay.
Zhang, Tao; Hu, Jiye; Zhang, Yuchao; Zhao, Qianfei; Ning, Jun
2011-09-01
JS-118 is an extensively used insecticide in China. The present study investigated the genotoxic effect of JS-118 on whole blood at 24, 48, 72 and 96 h by using alkaline comet assay. Male Kunming mice were given 6.25, 12.5, 25, 50 and 100 mg/kg BW of JS-118 intraperitoneally. A statistically significant increase in all comet parameters indicating DNA damage was observed at 24 h post-treatment (p < 0.05). A clear concentration-dependent increase of DNA damage was revealed as evident by the OTM (arbitrary units), tail length (µm) and tail DNA (%). From 48 h post-treatment, a gradual decrease in mean comet parameters was noted. By 96 h of post-treatment, the mean comet tail length reached control levels indicating repair of damaged DNA. This study on mice showed different DNA damage depending on the concentration of JS-118 and the period of treatment. The present study provided further information of the potential risk of the genetic damage caused by JS-118.
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Power law tails in phylogenetic systems.
Qin, Chongli; Colwell, Lucy J
2018-01-23
Covariance analysis of protein sequence alignments uses coevolving pairs of sequence positions to predict features of protein structure and function. However, current methods ignore the phylogenetic relationships between sequences, potentially corrupting the identification of covarying positions. Here, we use random matrix theory to demonstrate the existence of a power law tail that distinguishes the spectrum of covariance caused by phylogeny from that caused by structural interactions. The power law is essentially independent of the phylogenetic tree topology, depending on just two parameters-the sequence length and the average branch length. We demonstrate that these power law tails are ubiquitous in the large protein sequence alignments used to predict contacts in 3D structure, as predicted by our theory. This suggests that to decouple phylogenetic effects from the interactions between sequence distal sites that control biological function, it is necessary to remove or down-weight the eigenvectors of the covariance matrix with largest eigenvalues. We confirm that truncating these eigenvectors improves contact prediction.
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Novel gemini cationic lipids with carbamate groups for gene delivery
Zhao, Yi-Nan; Qureshi, Farooq; Zhang, Shu-Biao; Cui, Shao-Hui; Wang, Bing; Chen, Hui-Ying; Lv, Hong-Tao; Zhang, Shu-Fen; Huang, Leaf
2014-01-01
To obtain efficient non-viral vectors, a series of Gemini cationic lipids with carbamate linkers between headgroups and hydrophobic tails were synthesized. They have the hydrocarbon chains of 12, 14, 16 and 18 carbon atoms as tails, designated as G12, G14, G16 and G18, respectively. These Gemini cationic lipids were prepared into cationic liposomes for the study of the physicochemical properties and gene delivery. The DNA-bonding ability of these Gemini cationic liposomes was much better than their mono-head counterparts (designated as M12, M14, M16 and M18, respectively). In the same series of liposomes, bonding ability declined with an increase in tail length. They were tested for their gene-transferring capabilities in Hep-2 and A549 cells. They showed higher transfection efficiency than their mono-head counterparts and were comparable or superior in transfection efficiency and cytotoxicity to the commercial liposomes, DOTAP and Lipofectamine 2000. Our results convincingly demonstrate that the gene-transferring capabilities of these cationic lipids depended on hydrocarbon chain length. Gene transfection efficiency was maximal at a chain length of 14, as G14 can silence about 80 % of luciferase in A549 cells. Cell uptake results indicate that Gemini lipid delivery systems could be internalised by cells very efficiently. Thus, the Gemini cationic lipids could be used as synthetic non-viral gene delivery carriers for further study. PMID:25045521
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Connecting Structural and Transport Properties of Ionic Liquids with Cationic Oligoether Chains
Lall-Ramnarine, Sharon I.; Zhao, Man; Rodriguez, Chanele; ...
2017-06-01
We used X-ray diffraction and molecular dynamics simulations to probe the structures of two families of ionic liquids containing oligoether tails on the cations. Imidazolium and pyrrolidinium bis(trifluoromethylsulfonyl)amide ILs with side chains ranging from 4 to 10 atoms in length, including both linear alkyl and oligo-ethylene oxide tails, were prepared. Furthermore, their physical properties, such as viscosity, conductivity and thermal profile, were measured and compared for systematic trends. Consistent with earlier literature, a single ether substituent substantially decreases the viscosity of pyrrolidinium and imidazolium ILs compared to their alkyl congeners. Remarkably, as the number of ether units in the pyrrolidiniummore » ILs increases there is hardly any increase in the viscosity, in contrast to alkylpyrrolidinium ILs where the viscosity increases steadily with chain length. Viscosities of imidazolium ether ILs increase with chain length but always remain well below their alkyl congeners. To complement the experimentally determined properties, molecular dynamics simulations were run on the two ILs with the longest ether chains. Our results point to specific aspects that could be useful for researchers designing ILs for specific applications.« less
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Are X-rays the key to integrated computational materials engineering?
Ice, Gene E.
2015-11-01
The ultimate dream of materials science is to predict materials behavior from composition and processing history. Owing to the growing power of computers, this long-time dream has recently found expression through worldwide excitement in a number of computation-based thrusts: integrated computational materials engineering, materials by design, computational materials design, three-dimensional materials physics and mesoscale physics. However, real materials have important crystallographic structures at multiple length scales, which evolve during processing and in service. Moreover, real materials properties can depend on the extreme tails in their structural and chemical distributions. This makes it critical to map structural distributions with sufficient resolutionmore » to resolve small structures and with sufficient statistics to capture the tails of distributions. For two-dimensional materials, there are high-resolution nondestructive probes of surface and near-surface structures with atomic or near-atomic resolution that can provide detailed structural, chemical and functional distributions over important length scales. Furthermore, there are no nondestructive three-dimensional probes with atomic resolution over the multiple length scales needed to understand most materials.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Lall-Ramnarine, Sharon I.; Zhao, Man; Rodriguez, Chanele
We used X-ray diffraction and molecular dynamics simulations to probe the structures of two families of ionic liquids containing oligoether tails on the cations. Imidazolium and pyrrolidinium bis(trifluoromethylsulfonyl)amide ILs with side chains ranging from 4 to 10 atoms in length, including both linear alkyl and oligo-ethylene oxide tails, were prepared. Furthermore, their physical properties, such as viscosity, conductivity and thermal profile, were measured and compared for systematic trends. Consistent with earlier literature, a single ether substituent substantially decreases the viscosity of pyrrolidinium and imidazolium ILs compared to their alkyl congeners. Remarkably, as the number of ether units in the pyrrolidiniummore » ILs increases there is hardly any increase in the viscosity, in contrast to alkylpyrrolidinium ILs where the viscosity increases steadily with chain length. Viscosities of imidazolium ether ILs increase with chain length but always remain well below their alkyl congeners. To complement the experimentally determined properties, molecular dynamics simulations were run on the two ILs with the longest ether chains. Our results point to specific aspects that could be useful for researchers designing ILs for specific applications.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Lall-Ramnarine, Sharon I.; Zhao, Man; Rodriguez, Chanele
X-ray diffraction and molecular dynamics simulations were used to probe the structures of two families of ionic liquids containing oligoether tails on the cations. Imidazolium and pyrrolidinium bis(trifluoromethylsulfonyl)amide ILs with side chains ranging from 4 to 10 atoms in length, including both linear alkyl and oligo-ethylene oxide tails, were prepared. Their physical properties, such as viscosity, conductivity and thermal profile, were measured and compared for systematic trends. Consistent with earlier literature, a single ether substituent substantially decreases the viscosity of pyrrolidinium and imidazolium ILs compared to their alkyl congeners. Remarkably, as the number of ether units in the pyrrolidinium ILsmore » increases there is hardly any increase in the viscosity, in contrast to alkylpyrrolidinium ILs where the viscosity increases steadily with chain length. Viscosities of imidazolium ether ILs increase with chain length but always remain well below their alkyl congeners. To complement the experimentally determined properties, molecular dynamics simulations were run on the two ILs with the longest ether chains. The results point to specific aspects that could be useful for researchers designing ILs for specific applications.« less
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Teplitsky, Céline; Plénet, Sandrine; Joly, Pierre
2005-09-01
Inducible defences have long been considered as a polyphenism opposing defended and undefended morphs. However, in nature, preys are exposed to various levels of predation risk and scale their investment in defence to actual predation risk. Still, among the traits that are involved in the defence, some are specific to one predator type while others act as a more generalised defence. The existence of defence costs could prevent an individual investing in all these traits simultaneously. In this study, we investigate the impact of an increasing level of predator density (stickleback, Gasterosteus aculeatus) on the expression of morphological inducible defences in tadpoles of Rana dalmatina. In this species, investment in tail length and tail muscle is a stickleback-specific response while increased tail fin depth is a more general defence. As expected, we found a relationship between investment in defence and level of risk through the responses of tail fin depth and tail length. We also found an exponential increase of defence cost, notably expressed by convex decrease of growth and developmental rates. We found a relative independence of investment in the different traits that compose the defence, revealing a high potential for fine tuning the expression of defended phenotypes with respect to local ecological conditions.
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Sterk, Maaike; Romilly, Cédric; Wagner, E Gerhart H
2018-01-01
Abstract Initiation is the rate-limiting step in translation. It is well-known that stable structure at a ribosome binding site (RBS) impedes initiation. The ribosome standby model of de Smit and van Duin, based on studies of the MS2 phage coat cistron, proposed how high translation rates can be reconciled with stable, inhibitory structures at an RBS. Here, we revisited the coat protein system and assessed the translation efficiency from its sequestered RBS by introducing standby mutations. Further experiments with gfp reporter constructs assessed the effects of 5′-tails—as standby sites—with respect to length and sequence contributions. In particular, combining in vivo and in vitro assays, we can show that tails of CA-dinucleotide repeats—and to a lesser extent, AU-repeats—dramatically increase translation rates. Tails of increasing length reach maximal rate-enhancing effects at 16–18 nucleotides. These standby tails are single-stranded and do not exert their effect by structure changes in the neighboring RBS stem–loop. In vitro translation and toeprinting assays furthermore demonstrate that standby effects are exerted at the level of translation initiation. Finally, as expected, destabilizing mutations within the coat RBS indicate an interplay with the effects of standby tails. PMID:29420821
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NASA Astrophysics Data System (ADS)
Ruslin, Farhani; Yaakop, Salmah; Zain, Badrul Munir Md.
2014-09-01
The activity budget, ranging behaviour and feeding behaviour of a multimale-multifemale group of long-tailed macaques (Macaca fascicularis) and a multimale-multifemale group of spectacled dusky leaf monkey (Trachypithecus obscurus) were studied. A total of 145 hours and 143 hours have been spent to observe the group of long-tailed macaque and spectacled dusky leaf monkey that ranged the same habitat adjacent to the campus areas. The researchers examined the activity budgets, daily travel length and feeding activity of both species and distinguished how the sympatric species used the same forested habitat. Preliminary study found that the long-tailed macaques spent longer time feeding, moving than resting and other activities. On the other hand, the dusky leaf monkey spent much time in feeding and resting than moving. The differences of daily pattern between these two groups are significant. Macaques have higher daily mean of path length compared to the dusky leaf monkey and spent much time moving compare to the leaf monkey group. The spectacled dusky leaf monkey group also has fully utilized the forested areas where else the long-tailed macaques adopted foraging to the adjacent residential colleges.
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Garaj-Vrhovac, Verica; Gajski, Goran
2009-03-01
Several studies have reported radioprotective, antimutagenic, anti-inflammatory, antinociceptive, and anticancer effects of bee venom both in the cell and the whole organism. The aim of this study was to assess the effects of a single high dose of 100 microg mL(-1) of whole bee venom in human lymphocytes in vitro over a variety of time spans (from 10 min to 24 h). After the treatment, we used the comet assay and micronucleus test to see the effect of bee venom on the cell. The comet assay confirmed that the venom damaged the DNA molecule. Tail length, tail intensity, tail moment showed a significant increase (P < 0.05). The percentage of long-tailed nuclei (LTN) with the tail length exceeding the 95th percentile also increased in a time-dependent manner. The micronucleus parameters (number of micronuclei, nucleoplasmic bridges, and nuclear buds) also showed a significant time-dependent increase (P < 0.05). This research indicates that high concentrations of bee venom can lead to cellular instability. Further research is needed to understand the mechanism of action of bee venom and its components in human cells and to see if this natural product may find application in medicine.
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Modal analysis of passive flow control for the turbulent wake of a generic planar space launcher
NASA Astrophysics Data System (ADS)
Loosen, S.; Statnikov, V.; Meinke, M.; Schröder, W.
2018-06-01
The turbulent wake of a generic planar space launcher equipped with two passive flow control devices is simulated using a zonal RANS-LES method and analyzed by dynamic mode decomposition (DMD). In the first approach, the effect of a classical boat tail on the wake is examined. In the second concept, a flow control device consisting of semi-circular lobes integrated at the base shoulder of the main body is used. The objective of the two concepts is to reduce the reattachment length and thus the lever arm of the forces as well as to stabilize the separated shear layer. Using a boat tail, the reattachment length can be reduced by 50%. Furthermore, it is shown that the semi-circular lobes enhance the turbulent mixing and the shear layer growth rate. Hence, they significantly reduce the reattachment length by about 75%. The semi-circular lobes partially reduce undesired low-frequency pressure fluctuations on the nozzle surface. However, this reduction is achieved at the expense of an increase of high-frequency pressure fluctuations due to intensified small turbulent scales. The DMD analysis of the velocity field reveals that the large-scale coherent structures featuring a wave length of two step heights observed in the reference configuration without flow control can be suppressed by the lobes. The spanwise wave length of the coherent structures seems to depend on the geometry of the lobes, since all detected spatial DMD modes show a spanwise periodicity being equal to the distance between two lobes.
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Evaluation of developmental toxicity of guaifenesin using pregnant female rats.
Shabbir, Arham; Shamsi, Sadia; Shahzad, Muhammad; Butt, Hajra Ikram; Aamir, Khurram; Iqbal, Javed
2016-01-01
Guaifenesin possesses expectorant, muscle relaxant, and anticonvulsive properties. To the best of our knowledge, the promising data regarding the developmental toxicity of guaifenesin are scarce. The current study investigates the developmental toxic effects of guaifenesin in detail using female rats. Twenty-five dams were divided into five groups. Group 1 served as a control, while Group-2, -3, -4, and -5 were administered with 250, 350, 500, and 600 (mg/kg b.w.) doses of guaifenesin, respectively, starting from gestation day 6 to day 17. Half of the total recovered fetuses was subjected to morphologic and morphometric analysis, while other half was subjected to skeletal examination. A significant reduction in maternal weight, and food/water intake, was observed, however, no mortality and morbidity were observed. About 14 dead fetuses were found in Group-3 and -4 each, while 26 in Group 5. Morphological analysis revealed 21.2%, 45.4%, 67.2%, and 86.9% of total fetuses having hemorrhagic spots in Group-2, -3, -4, and -5, respectively. Dropping wrist/ankle and kinky tail were found in Group-4 and -5 only. Morphometric analysis showed a significant decline in fetal weight, full body length, skull length, forelimb length, hindlimb length, and tail length in all guaifenesin treated groups. Skeletal examination displayed that only Group 5 fetuses had increased intercostal space between 7(th) and 8(th) rib. We also observed improper development of carpals, metacarpals, tarsals, and metatarsals of the Group 5 fetuses. Guaifenesin showed a significant developmental toxicity at selected test doses; therefore, a careful use is suggested during pregnancy.
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Evaluation of developmental toxicity of guaifenesin using pregnant female rats
Shabbir, Arham; Shamsi, Sadia; Shahzad, Muhammad; Butt, Hajra Ikram; Aamir, Khurram; Iqbal, Javed
2016-01-01
Objectives: Guaifenesin possesses expectorant, muscle relaxant, and anticonvulsive properties. To the best of our knowledge, the promising data regarding the developmental toxicity of guaifenesin are scarce. The current study investigates the developmental toxic effects of guaifenesin in detail using female rats. Materials and Methods: Twenty-five dams were divided into five groups. Group 1 served as a control, while Group-2, -3, -4, and -5 were administered with 250, 350, 500, and 600 (mg/kg b.w.) doses of guaifenesin, respectively, starting from gestation day 6 to day 17. Half of the total recovered fetuses was subjected to morphologic and morphometric analysis, while other half was subjected to skeletal examination. Results: A significant reduction in maternal weight, and food/water intake, was observed, however, no mortality and morbidity were observed. About 14 dead fetuses were found in Group-3 and -4 each, while 26 in Group 5. Morphological analysis revealed 21.2%, 45.4%, 67.2%, and 86.9% of total fetuses having hemorrhagic spots in Group-2, -3, -4, and -5, respectively. Dropping wrist/ankle and kinky tail were found in Group-4 and -5 only. Morphometric analysis showed a significant decline in fetal weight, full body length, skull length, forelimb length, hindlimb length, and tail length in all guaifenesin treated groups. Skeletal examination displayed that only Group 5 fetuses had increased intercostal space between 7th and 8th rib. We also observed improper development of carpals, metacarpals, tarsals, and metatarsals of the Group 5 fetuses. Conclusion: Guaifenesin showed a significant developmental toxicity at selected test doses; therefore, a careful use is suggested during pregnancy. PMID:27298495
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Modal analysis of passive flow control for the turbulent wake of a generic planar space launcher
NASA Astrophysics Data System (ADS)
Loosen, S.; Statnikov, V.; Meinke, M.; Schröder, W.
2017-12-01
The turbulent wake of a generic planar space launcher equipped with two passive flow control devices is simulated using a zonal RANS-LES method and analyzed by dynamic mode decomposition (DMD). In the first approach, the effect of a classical boat tail on the wake is examined. In the second concept, a flow control device consisting of semi-circular lobes integrated at the base shoulder of the main body is used. The objective of the two concepts is to reduce the reattachment length and thus the lever arm of the forces as well as to stabilize the separated shear layer. Using a boat tail, the reattachment length can be reduced by 50%. Furthermore, it is shown that the semi-circular lobes enhance the turbulent mixing and the shear layer growth rate. Hence, they significantly reduce the reattachment length by about 75%. The semi-circular lobes partially reduce undesired low-frequency pressure fluctuations on the nozzle surface. However, this reduction is achieved at the expense of an increase of high-frequency pressure fluctuations due to intensified small turbulent scales. The DMD analysis of the velocity field reveals that the large-scale coherent structures featuring a wave length of two step heights observed in the reference configuration without flow control can be suppressed by the lobes. The spanwise wave length of the coherent structures seems to depend on the geometry of the lobes, since all detected spatial DMD modes show a spanwise periodicity being equal to the distance between two lobes.
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On the error probability of general tree and trellis codes with applications to sequential decoding
NASA Technical Reports Server (NTRS)
Johannesson, R.
1973-01-01
An upper bound on the average error probability for maximum-likelihood decoding of the ensemble of random binary tree codes is derived and shown to be independent of the length of the tree. An upper bound on the average error probability for maximum-likelihood decoding of the ensemble of random L-branch binary trellis codes of rate R = 1/n is derived which separates the effects of the tail length T and the memory length M of the code. It is shown that the bound is independent of the length L of the information sequence. This implication is investigated by computer simulations of sequential decoding utilizing the stack algorithm. These simulations confirm the implication and further suggest an empirical formula for the true undetected decoding error probability with sequential decoding.
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Lauw, Y; Leermakers, F A M; Stuart, M A Cohen
2007-07-19
The persistence length of a wormlike micelle composed of ionic surfactants C(n)E(m)X(k) in an aqueous solvent is predicted by means of the self-consistent-field theory where C(n)E(m) is the conventional nonionic surfactant and X(k) is an additional sequence of k weakly charged (pH-dependent) segments. By considering a toroidal micelle at infinitesimal curvature, we evaluate the bending modulus of the wormlike micelle that corresponds to the total persistence length, consisting of an elastic/intrinsic and an electrostatic contribution. The total persistence length increases with pH and decreases with increasing background salt concentration. We estimate that the electrostatic persistence length l(p,e)(0) scales with respect to the Debye length kappa(-1) as l(p,e)(0) approximately kappa(-p) where p approximately 1.98 for wormlike micelles consisting of C(20)E(10)X(1) surfactants and p approximately 1.54 for wormlike micelles consisting of C(20)E(10)X(2) surfactants. The total persistence length l(p,t)(0) is a weak function of the head group length m but scales with the tail length n as l(p,t)(0) approximately n(x) where x approximately 2-2.6, depending on the corresponding head group length. Interestingly, l(p,t)(0) varies nonmonotonically with the number of charged groups k due to the opposing trends in the electrostatic and elastic bending rigidities upon variation of k.
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Assessment of DNA damage and repair efficiency in drug naïve schizophrenia using comet assay.
Muraleedharan, Aparna; Menon, Vikas; Rajkumar, Ravi Philip; Chand, Parkash
2015-09-01
The etiology of schizophrenia continues to be confounding and elusive. Some knowledge gaps exist in the neurodegenerative theory of schizophrenia. Oxidative DNA damage and repair deficits are relevant to the mechanisms of neurodegeneration but have not been studied in drug naïve schizophrenia. The present study used the comet assay technique to study the extent of DNA damage in circulating peripheral lymphocytes of patients with drug naïve schizophrenia (n = 40) along with an age and gender matched control group (n = 40). We also assessed the DNA repair efficiency in cases following incubation in a nutrient medium. All the assayed comet parameters demonstrated significantly greater baseline DNA damage in cases in comparison to the controls except for head diameter (p < 0.001 for all significant results, p = 0.32 for head diameter). Gender, age and duration of illness (p = 0.21, 0.69 and 0.12 respectively for tail length) did not influence any of the parameters significantly. Significant decrease was noted in the comet tail length and percentage of DNA in comet tail (p < 0.001 for both) in cases following incubation suggesting that the DNA repair machinery was preserved. No difference in DNA repair efficiency was noted between the genders (p = 0.23 for tail length). Our findings confirm the presence of significant baseline DNA damage in schizophrenia even prior to the initiation of anti-psychotic treatment. Additionally, intact genomic repair efficiency was noted in this group as a whole. These results provide some evidence for oxidative DNA damage as molecular link underpinning neurodegeneration in drug naïve schizophrenia. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Yoon, Jungju; Kwag, Jungheon; Shin, Tae Joo; Park, Joonhyuck; Lee, Yong Man; Lee, Yebin; Park, Jonghyup; Heo, Jung; Joo, Chulmin; Park, Tae Jung; Yoo, Pil J; Kim, Sungjee; Park, Juhyun
2014-07-09
Phase separation in films of phospholipids and conjugated polymers results in nanoassemblies because of a difference in the physicochemical properties between the hydrophobic polymers and the polar lipid heads, together with the comparable polymer side-chain lengths to lipid tail lengths, thus producing nanoparticles of conjugated polymers upon disassembly in aqueous media by the penetration of water into polar regions of the lipid heads. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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First report of Ancylostoma tubaeforme in Persian Leopard (Panthera pardus saxicolor)
Youssefi, MR; Hoseini, SH; Hoseini, SM; Zaheri, BA; Tabari, M Abouhosseini
2010-01-01
Ancylostoma tubaeforme was originally described as a separate species parasitizing the cat. The adults of A. tubaeforme are 7 to 12 mm long. A. tubaeforme can be differentiated from the adults of A. braziliense and A. ceylanicum by the presence of three teeth. Here we describe the first report of A. tubaeforme in a Persian young female leopard, 2–3 years old, with head and trunk length 120 centimeters, length of tail 98 centimeters and body weight 35 kilograms. PMID:22347237
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First report of Ancylostoma tubaeforme in Persian Leopard (Panthera pardus saxicolor).
Youssefi, Mr; Hoseini, Sh; Hoseini, Sm; Zaheri, Ba; Tabari, M Abouhosseini
2010-03-01
Ancylostoma tubaeforme was originally described as a separate species parasitizing the cat. The adults of A. tubaeforme are 7 to 12 mm long. A. tubaeforme can be differentiated from the adults of A. braziliense and A. ceylanicum by the presence of three teeth. Here we describe the first report of A. tubaeforme in a Persian young female leopard, 2-3 years old, with head and trunk length 120 centimeters, length of tail 98 centimeters and body weight 35 kilograms.
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NASA Astrophysics Data System (ADS)
Phillips, R. C.; Samadi, S. Z.; Meadows, M. E.
2018-07-01
This paper examines the frequency, distribution tails, and peak-over-threshold (POT) of extreme floods through analysis that centers on the October 2015 flooding in North Carolina (NC) and South Carolina (SC), United States (US). The most striking features of the October 2015 flooding were a short time to peak (Tp) and a multi-hour continuous flood peak which caused intensive and widespread damages to human lives, properties, and infrastructure. The 2015 flooding was produced by a sequence of intense rainfall events which originated from category 4 hurricane Joaquin over a period of four days. Here, the probability distribution and distribution parameters (i.e., location, scale, and shape) of floods were investigated by comparing the upper part of empirical distributions of the annual maximum flood (AMF) and POT with light- to heavy- theoretical tails: Fréchet, Pareto, Gumbel, Weibull, Beta, and Exponential. Specifically, four sets of U.S. Geological Survey (USGS) gauging data from the central Carolinas with record lengths from approximately 65-125 years were used. Analysis suggests that heavier-tailed distributions are in better agreement with the POT and somewhat AMF data than more often used exponential (light) tailed probability distributions. Further, the threshold selection and record length affect the heaviness of the tail and fluctuations of the parent distributions. The shape parameter and its evolution in the period of record play a critical and poorly understood role in determining the scaling of flood response to intense rainfall.
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NASA Technical Reports Server (NTRS)
Riebe, John M; Naeseth, Rodger L
1953-01-01
An investigation was made in the Langley 300 mph 7-by 10-foot tunnel to determine the aerodynamic characteristics of a refined deep-step planing-tail hull with various forebody and afterbody shapes. For comparison, tests were made on a streamline body simulating the fuselage of a modern transport airplane. The results of the tests, which include the interference effects of a 21-percent-thick support wing, indicated that for corresponding configurations the hull models incorporating a forebody with a length-beam ratio of 7 had lower minimum drag coefficients than the hull models incorporating a forebody with a length-beam ratio of 5. Longitudinal and lateral stability was generally about the same for all hull models tested and about the same as that of a conventional hull.
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Hoff, G R
2009-02-01
Embryo development events were correlated with egg-case changes for the Aleutian skate Bathyraja aleutica and the Alaska skate Bathyraja parmifera. Yolk absorption underwent two phases: that of steady absorption during early development and that of rapid yolk absorption during the final development stages. Total length (L(T)) for 50% of the pre-hatching embryos egg-case jelly disappearance was 92.04 mm (range 81-102 mm) and 99.36 mm (range 81-100 mm) for B. aleutica and B. parmifera, respectively, allowing the inner chamber to open to seawater flow. The tail filament underwent three phases of growth: rapid elongation during early development (<100 mm embryo L(T)), stasis of tail filament length during the remainder of embryo development and rapid absorption soon after hatching. Complete tail filament development coincided with the disappearance of egg-case jelly. Clasper buds first developed at embryos >70 mm L(T) for both species and the sex ratio was 1:1 well before hatching. Egg cases that were devoid of an ova or developing embryo were c. 5.0 and 6.5% of the egg cases examined for B. aleutica and B. parmifera, respectively. Measurements showed that egg cases containing only egg jelly were smaller in both width and length than those possessing an ova. Embryo stages were punctuated with distinct events that correlated with egg case changes controlling the internal environment of the developing embryo.
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NASA Technical Reports Server (NTRS)
Klemin, Alexander; Warner, Edward P; Denkinger, George M
1918-01-01
Part 1 gives details of models tested and methods of testing of the Eiffel 36 wing alone and the JN2 aircraft. Characteristics and performance curves for standard JN are included. Part 2 presents a statistical analysis of the following: lift and drag contributed by body and chassis tested without wings; lift and drag contributed by tail, tested without wings; the effect on lift and drift of interference between the wings of a biplane combination; lift and drag contributed by the addition of body, chassis, and tail to a biplane combination; total parasite resistance; effect of varying size of tail, keeping angle of setting constant; effect of varying length of body and size of tail at the same time, keeping constant moment of tail surface about the center of gravity; forces on the tail and the effects of downwash; effect of size and setting of tail on statical longitudinal stability effects of length of body on stability; the effects of the various elements of an airplane on longitudinal stability and the placing of the force vectors. Part 3 presents the fundamental principals of dynamical stability; computations of resistance derivatives; solution of the stability equation; dynamical stability of the Curtiss JN2; tabulation of resistance derivatives; discussion of the resistance derivatives; formation and solution of stability equations; physical conceptions of the resistance derivatives; elements contributing to damping and an investigation of low speed conditions. Part 4 includes a summary of the results of the statistical investigation and a summary of the results for dynamic stability.
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The Effect of Lengthening Cation Ether Tails on Ionic Liquid Properties
Lall-Ramnarine, S.; Rodriguez, C.; Fernandez, R.; ...
2016-08-30
In order to explore the effect of multiple ether functionalities on ionic liquid properties, a series of ten pyrrolidinium ionic liquids and ten imidazolium ionic liquids bearing ether and alkyl side chains of varying lengths (4 to 10 atoms in length) were prepared for this study. Their physical properties, such as viscosity, conductivity and thermal profile were measured and compared. Consistent with earlier literature, a single ether substituent substantially decreases the viscosity of pyrrolidinium and imidazolium ILs compared to their alkyl congeners. Remarkably, as the number of ether units in the pyrrolidinium ILs increases there is hardly any increase inmore » the viscosity, in contrast to alkylpyrrolidinium ILs where the viscosity increases steadily with chain length. Viscosities of imidazolium ether ILs increase with chain length but always remain well below their alkyl congeners. These results provide significant insight on the choice of starting materials for researchers designing ILs for specific applications.« less
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Uldahl, Kristine B.; Jensen, Signe B.; Bhoobalan-Chitty, Yuvaraj; Martínez-Álvarez, Laura; Papathanasiou, Pavlos
2016-01-01
ABSTRACT We provide here, for the first time, insights into the initial infection stages of a large spindle-shaped archaeal virus and explore the following life cycle events. Our observations suggest that Sulfolobus monocaudavirus 1 (SMV1) exhibits a high adsorption rate and that virions adsorb to the host cells via three distinct attachment modes: nosecone association, body association, and body/tail association. In the body/tail association mode, the entire virion, including the tail(s), aligns to the host cell surface and the main body is greatly flattened, suggesting a possible fusion entry mechanism. Upon infection, the intracellular replication cycle lasts about 8 h, at which point the virions are released as spindle-shaped tailless particles. Replication of the virus retarded host growth but did not cause lysis of the host cells. Once released from the host and at temperatures resembling that of its natural habitat, SMV1 starts developing one or two tails. This exceptional property of undergoing a major morphological development outside, and independently of, the host cell has been reported only once before for the related Acidianus two-tailed virus. Here, we show that SMV1 can develop tails of more than 900 nm in length, more than quadrupling the total virion length. IMPORTANCE Very little is known about the initial life cycle stages of viruses infecting hosts of the third domain of life, Archaea. This work describes the first example of an archaeal virus employing three distinct association modes. The virus under study, Sulfolobus monocaudavirus 1, is a representative of the large spindle-shaped viruses that are frequently found in acidic hot springs. The results described here will add valuable knowledge about Archaea, the least studied domain in the virology field. PMID:27053548
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Uldahl, Kristine B; Jensen, Signe B; Bhoobalan-Chitty, Yuvaraj; Martínez-Álvarez, Laura; Papathanasiou, Pavlos; Peng, Xu
2016-06-15
We provide here, for the first time, insights into the initial infection stages of a large spindle-shaped archaeal virus and explore the following life cycle events. Our observations suggest that Sulfolobus monocaudavirus 1 (SMV1) exhibits a high adsorption rate and that virions adsorb to the host cells via three distinct attachment modes: nosecone association, body association, and body/tail association. In the body/tail association mode, the entire virion, including the tail(s), aligns to the host cell surface and the main body is greatly flattened, suggesting a possible fusion entry mechanism. Upon infection, the intracellular replication cycle lasts about 8 h, at which point the virions are released as spindle-shaped tailless particles. Replication of the virus retarded host growth but did not cause lysis of the host cells. Once released from the host and at temperatures resembling that of its natural habitat, SMV1 starts developing one or two tails. This exceptional property of undergoing a major morphological development outside, and independently of, the host cell has been reported only once before for the related Acidianus two-tailed virus. Here, we show that SMV1 can develop tails of more than 900 nm in length, more than quadrupling the total virion length. Very little is known about the initial life cycle stages of viruses infecting hosts of the third domain of life, Archaea This work describes the first example of an archaeal virus employing three distinct association modes. The virus under study, Sulfolobus monocaudavirus 1, is a representative of the large spindle-shaped viruses that are frequently found in acidic hot springs. The results described here will add valuable knowledge about Archaea, the least studied domain in the virology field. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
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NASA Technical Reports Server (NTRS)
Pitts, William C; Nielsen, Jack N; Kaattari, George E
1957-01-01
A method is presented for calculating the lift and centers of pressure of wing-body and wing-body-tail combinations at subsonic, transonic, and supersonic speeds. A set of design charts and a computing table are presented which reduce the computations to routine operations. Comparison between the estimated and experimental characteristics for a number of wing-body and wing-body-tail combinations shows correlation to within + or - 10 percent on lift and to within about + or - 0.02 of the body length on center of pressure.
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Rusek, Jakub; Thiel, Michaela; Wolinska, Justyna; Laforsch, Christian
2017-01-01
Microplastic particles are ubiquitous not only in marine but also in freshwater ecosystems. However, the impacts of microplastics, consisting of a large variety of synthetic polymers, on freshwater organisms remains poorly understood. We examined the effects of two polymer mixtures on the morphology, life history and on the molecular level of the waterflea Daphnia magna (three different clones). Microplastic particles of ~40 μm were supplied at a low concentration (1% of the food particles) leading to an average of ~30 particles in the digestive tract which reflects a high microplastic contamination but still resembles a natural situation. Neither increased mortality nor changes on the morphological (body length, width and tail spine length) or reproductive parameters were observed for adult Daphnia. The analyses of juvenile Daphnia revealed a variety of small and rather subtle responses of morphological traits (body length, width and tail spine length). For adult Daphnia, alterations in expression of genes related to stress responses (i.e. HSP60, HSP70 & GST) as well as of other genes involved in body function and body composition (i.e. SERCA) were observed already 48h after exposure. We anticipate that the adverse effects of microplastic might be influenced by many additional factors like size, shape, type and even age of the particles and that the rather weak effects, as detected in a laboratory, may lead to reduced fitness in a natural multi-stressor environment. PMID:29145427
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Dodd, C.K.
1993-01-01
The snout – vent length, tail length, weight, sex, activity, and orientation of a population of swamp snakes (Seminatrix pygaea) in north – central Florida were recorded from 1985 through 1990. A small temporary pond was monitored for 1343 days, using a drift fence – pitfall trap sampling regime. I captured 123 different snakes, plus 45 recaptures. Juveniles comprised 89% of the snakes at the pond. Females were generally longer and weighed more than males, although regression analysis showed no differences between the sexes in the relationship of length versus wet body mass. Males had longer tails than females. The sex ratio of snakes with a snout – vent length of more than 150 mm was 1:1. Activity occurred throughout the year but peaked during summer. Hydroperiod and weather conditions did not appear to influence snake activity. During the latter years of the study, a regional drought that began in the mid-1980s became quite severe. However, drought had little direct effect on overland migration or body condition but caused snakes to leave or to shorten the amount of time they spent within the pond basin. Snakes immigrated and emigrated nonrandomly; orientation was directed to and from the nearest large water body. Certain temporary ponds may comprise developmental habitat for Seminatrix pygaea. The dynamic wet – dry climatic cycles in southeastern North America may lead to the formation of metapopulations in some aquatic snakes.
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Martinez, Josue G; Bohn, Kirsten M; Carroll, Raymond J; Morris, Jeffrey S
2013-06-01
We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to capture correlation within the spectrogram in our modeling and obtain adaptive regularization of the estimates and inference for the regions-specific spectrograms. Our model includes random effect spectrograms at the bat level to account for correlation among chirps from the same bat, and to assess relative variability in chirp spectrograms within and between bats. The modeling of spectrograms using functional mixed models is a general approach for the analysis of replicated nonstationary time series, such as our acoustical signals, to relate aspects of the signals to various predictors, while accounting for between-signal structure. This can be done on raw spectrograms when all signals are of the same length, and can be done using spectrograms defined on a relative time scale for signals of variable length in settings where the idea of defining correspondence across signals based on relative position is sensible.
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Morphometry of boar sperm head and flagellum in semen backflow after insemination.
García-Vázquez, Francisco Alberto; Hernández-Caravaca, Iván; Yánez-Quintana, Wellington; Matás, Carmen; Soriano-Úbeda, Cristina; Izquierdo-Rico, María José
2015-09-01
Once deposited in the female reproductive system, sperm begin their competition and undergo a selection to reach the site of fertilization. Little is known about the special characteristics of sperm that reach the oviduct and are able to fertilize, with even less information on the role of sperm dimension and shape in transport and fertilization. Here, we examine whether sperm morphometry could be involved in their journey within the uterus. For this purpose, sperm head dimension (length, width, area, and perimeter) and shape (shape factor, ellipticity, elongation, and regularity), and flagellum length were analyzed in the backflow at different times after insemination (0-15, 16-30, and 31-60 minutes). Sperm morphometry in the backflow was also analyzed taking into account the site of semen deposition (cervical vs. intrauterine). Finally, flagellum length was measured at the uterotubal junction. Sperm analyzed in the backflow were small (head and flagellum) with different head shapes compared with sperm observed in the dose before insemination. The site of deposition influenced head morphometry and tail size both being smaller in the backflow after cervical insemination compared with intrauterine insemination. Mean tail length of sperm collected in the backflow was smaller than that in the insemination dose and at the uterotubal junction. Overall, our results suggest that sperm size may be involved in sperm transport either because of environment or through sperm selection and competence on their way to encounter the female gamete. Copyright © 2015 Elsevier Inc. All rights reserved.
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Xu, Jing; Guo, Chang-jiang; Yang, Ji-jun; Wei, Jing-yu; Li, Yun-feng; Pang, Wei; Jiang, Yu-gang; Cheng, Shuang
2005-03-01
To observe the effects of fruit juices with different antioxidant capacity on antioxidant system function of aged rats. Thirty Wistar rats were randomly divided into three groups: pomegranate juice and apple juice as two experimental groups, while distilled water as normal control group. They were administrated fruit juices or distilled water respectively by gavage daily for 4 weeks. At the end of experiment, the antioxidant system function was assessed. The aged rats in pomegranate juice group showed significantly higher serum antioxidant capacity (0.90 +/- 0.13) mmol/L than that in control group (0.79 +/- 0.10) mmol/L (P < 0.05). The concentrations of serum carbonyl and oxLDL were decreased significantly in pomegranate juice group as compared to the control group (P < 0.05). The percentage of injured blood lymphocyte DNA and the ratio of tail length/total length were declined significantly in pomegranate juice group (P < 0.05 and P < 0.01 respectively). The apple juice showed no effects except decreased ratio of tail length/total length of injured lymphocyte DNA. There were no changes in concentrations of serum vitamin C, vitamin E, urinary 8-OH-dG excretion and the activities of serum SOD, GSH-Px, CAT among three groups. The pomegranate juice should possess higher antioxidant capacity and might improve the antioxidant system function of aged rats, while the apple juice is relatively lower in antioxidant capacity and not very effective. The polyphenols in pomegranate juice might be the important functional components.
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Cutillas, Cristina; de Rojas, Manuel; Zurita, Antonio; Oliveros, Rocío; Callejón, Rocío
2014-07-01
In the present work, a morphological and biometrical study of whipworms Trichuris Roederer, 1761 (Nematoda: Trichuridae) parasitizing Colobus guereza kikuyensis has been carried out. Biometrical and statistical data showed that the mean values of individual variables between Trichuris suis and Trichuris sp. from C. g. kikuyensis differed significantly (P < 0.001) when Student's t test was performed: seven male variables (width of esophageal region of body, maximum width of posterior region of body, width in the place of junction of esophagus and the intestine, length of bacillary stripes, length of spicule, length of ejaculatory duct, and distance between posterior part of testis and tail end of body) and three female variables (width of posterior region of body, length of bacillary stripes, and distance of tail end of body and posterior fold of seminal receptacle). The combination of these characters permitted the discrimination of T. suis with respect to Trichuris sp. from C. g. kikuyensis, suggesting a new species of Trichuris. Furthermore, males of Trichuris sp. from C. g. kikuyensis showed a typical subterminal pericloacal papillae associated to a cluster of small papillae that were absent in males of T. suis, while females of Trichuris from Colobus appeared with a vulval region elevated/over-mounted showing a crater-like appearance. The everted vagina showed typical triangular sharp spines by optical microscopy and SEM. Thus, the existence of a new species of Trichuris parasitizing C. g. kikuyensis has been proposed.
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Imhof, Hannes K; Rusek, Jakub; Thiel, Michaela; Wolinska, Justyna; Laforsch, Christian
2017-01-01
Microplastic particles are ubiquitous not only in marine but also in freshwater ecosystems. However, the impacts of microplastics, consisting of a large variety of synthetic polymers, on freshwater organisms remains poorly understood. We examined the effects of two polymer mixtures on the morphology, life history and on the molecular level of the waterflea Daphnia magna (three different clones). Microplastic particles of ~40 μm were supplied at a low concentration (1% of the food particles) leading to an average of ~30 particles in the digestive tract which reflects a high microplastic contamination but still resembles a natural situation. Neither increased mortality nor changes on the morphological (body length, width and tail spine length) or reproductive parameters were observed for adult Daphnia. The analyses of juvenile Daphnia revealed a variety of small and rather subtle responses of morphological traits (body length, width and tail spine length). For adult Daphnia, alterations in expression of genes related to stress responses (i.e. HSP60, HSP70 & GST) as well as of other genes involved in body function and body composition (i.e. SERCA) were observed already 48h after exposure. We anticipate that the adverse effects of microplastic might be influenced by many additional factors like size, shape, type and even age of the particles and that the rather weak effects, as detected in a laboratory, may lead to reduced fitness in a natural multi-stressor environment.
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Boback, Scott M.; Snow, Ray W.; Hsu, Teresa; Peurach, Suzanne C.; Dove, Carla J.; Reed, Robert N.
2016-01-01
Snakes have become successful invaders in a wide variety of ecosystems worldwide. In southern Florida, USA, the Burmese python (Python molurus bivittatus) has become established across thousands of square kilometers including all of Everglades National Park (ENP). Both experimental and correlative data have supported a relationship between Burmese python predation and declines or extirpations of mid- to large-sized mammals in ENP. In June 2013 a large python (4.32 m snout-vent length, 48.3 kg) was captured and removed from the park. Subsequent necropsy revealed a massive amount of fecal matter (79 cm in length, 6.5 kg) within the snake’s large intestine. A comparative examination of bone, teeth, and hooves extracted from the fecal contents revealed that this snake consumed three white-tailed deer (Odocoileus virginianus). This is the first report of an invasive Burmese python containing the remains of multiple white-tailed deer in its gut. Because the largest snakes native to southern Florida are not capable of consuming even mid-sized mammals, pythons likely represent a novel predatory threat to white-tailed deer in these habitats. This work highlights the potential impact of this large-bodied invasive snake and supports the need for more work on invasive predator-native prey relationships.
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Paulose, Swetha; Rangdhol, Vishwanath; Ramesh, Ramasamy; Jeelani, Siccandar Ali; Brooklyin, Sivakumar
2016-08-01
To quantify the level of serum malondialdehyde and extent of DNA damage using comet assay in patients with oral submucous fibrosis (SMF) in comparison to normal individuals and to correlate the extent of DNA damage with MDA levels. Study included 30 cases of SMF (n = 30) and equal number of healthy volunteers. Serum malondialdehyde was measured using the thiobarbituric-trichloroacetitic acid (TBA-TCA) method. Comet assay was used to assess the DNA damage. Association between the extent of DNA damage and serum MDA levels was analyzed in SMF statistically. Comet assay results showed that there was an increase in tail length, percentage of tail DNA and tail moment among SMF subjects (P < 0.05). Serum MDA levels were elevated in SMF patients compared with healthy subjects. A significant positive correlation was observed between serum MDA levels and comet tail length in SMF group (r = 0.56; P < 0.05). Patients with SMF have increased DNA damage and elevated levels of lipid peroxidation compared with healthy controls. Evaluation of MDA levels as an oxidative biomarker along with comet assay analysis will serve as a diagnostic tool to identify patients with high risk of malignant potential in SMF. © 2015 Wiley Publishing Asia Pty Ltd.
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On the rules for aquatic locomotion
NASA Astrophysics Data System (ADS)
Saadat, M.; Fish, F. E.; Domel, A. G.; Di Santo, V.; Lauder, G. V.; Haj-Hariri, H.
2017-08-01
We present unifying rules governing the efficient locomotion of swimming fish and marine mammals. Using scaling and dimensional analysis, supported by new experimental data, we show that efficient locomotion occurs when the values of the Strouhal (St) number St (=f A /U ) and A*(=A /L ) , two nondimensional numbers that relate forward speed U , tail-beat amplitude A , tail-beat frequency f , and the length of the swimmer L are bound to the tight ranges of 0.2-0.4 and 0.1-0.3, respectively. The tight range of 0.2-0.4 for the St number has previously been associated with optimal thrust generation. We show that the St number alone is insufficient to achieve optimal aquatic locomotion, and an additional condition on A* is needed. More importantly, we show that when swimming at minimal power consumption, the Strouhal number of a cruising swimmer is predetermined solely by the shape and drag characteristics of the swimmer. We show that diverse species of fish and cetaceans cruise indeed with the St number and A* predicted by our theory. Our findings provide a physical explanation as to why fast aquatic swimmers cruise with a relatively constant tail-beat amplitude of approximately 20% of the body length, and their swimming speed is nearly proportional to their tail-beat frequency.
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Actin-based propulsion of a microswimmer.
Leshansky, A M
2006-07-01
A simple hydrodynamic model of actin-based propulsion of microparticles in dilute cell-free cytoplasmic extracts is presented. Under the basic assumption that actin polymerization at the particle surface acts as a force dipole, pushing apart the load and the free (nonanchored) actin tail, the propulsive velocity of the microparticle is determined as a function of the tail length, porosity, and particle shape. The anticipated velocities of the cargo displacement and the rearward motion of the tail are in good agreement with recently reported results of biomimetic experiments. A more detailed analysis of the particle-tail hydrodynamic interaction is presented and compared to the prediction of the simplified model.
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Variation in age at metamorphosis across a latitudinal gradient for the tailed frog, Ascaphus truei
Bury, R. Bruce; Adams, Michael J.
1999-01-01
Tailed frogs (Ascaphus truei) occur in permanent, cold streams in northwestern North America. Their tadpoles reportedly undergo metamorphosis after 2-4 years. Coastal populations that we examined transformed in 2 yr from the Olympic peninsula in Washington to northern Oregon, but in 1 yr from central Oregon to northern California. One inland site in northern California had a 2-yr period. Age at metamorphosis was consistent over different years. We suggest that total length and developmental stage accurately define cohorts for larval Ascaphus. Hind-leg length indicates whether metamorphs are a separate age class from tadpoles. Age at metamorphosis (1-4 yr) appears to reflect broad differences in climatic conditions. However, at a regional scale, variation is low and suggests a lack of sensitivity to local environmental conditions. This may be due to seasonal constraints on the time when metamorphosis occurs (late summer).
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Pseudorotational epitaxy of self-assembled octadecyltrichlorosilane monolayers on sapphire (0001)
Steinrück, H. -G.; Magerl, A.; Deutsch, M.; ...
2014-10-06
The structure of octadecyltrichlorosilane self-assembled monolayers (SAMs) on sapphire (0001) was studied by Å-resolution surface-specific x-ray scattering methods. The monolayer was found to consist of three sublayers where the outermost layer corresponds to vertically oriented, closely packed alkyl tails. Laterally, the monolayer is hexagonally packed and exhibits pseudorotational epitaxy to the sapphire, manifested by a broad scattering peak at zero relative azimuthal rotation, with long powderlike tails. The lattice mismatch of ~1% – 3% to the sapphire’s and the different length scale introduced by the lateral Si-O-Si bonding prohibit positional epitaxy. However, the substrate induces an intriguing increase in themore » crystalline coherence length of the SAM’s powderlike crystallites when rotationally aligned with the sapphire’s lattice. As a result, the increase correlates well with the rotational dependence of the separation of corresponding substrate-monolayer lattice sites.« less
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Quintero, Omar A.; Weck, Meredith L.; Unrath, William C.; Gallagher, James W.; Cui, Runjia; Kachar, Bechara; Tyska, Matthew J.; Yengo, Christopher M.
2016-01-01
Class III myosins (MYO3A and MYO3B) are proposed to function as transporters as well as length and ultrastructure regulators within stable actin-based protrusions such as stereocilia and calycal processes. MYO3A differs from MYO3B in that it contains an extended tail domain with an additional actin-binding motif. We examined how the properties of the motor and tail domains of human class III myosins impact their ability to enhance the formation and elongation of actin protrusions. Direct examination of the motor and enzymatic properties of human MYO3A and MYO3B revealed that MYO3A is a 2-fold faster motor with enhanced ATPase activity and actin affinity. A chimera in which the MYO3A tail was fused to the MYO3B motor demonstrated that motor activity correlates with formation and elongation of actin protrusions. We demonstrate that removal of individual exons (30–34) in the MYO3A tail does not prevent filopodia tip localization but abolishes the ability to enhance actin protrusion formation and elongation in COS7 cells. Interestingly, our results demonstrate that MYO3A slows filopodia dynamics and enhances filopodia lifetime in COS7 cells. We also demonstrate that MYO3A is more efficient than MYO3B at increasing formation and elongation of stable microvilli on the surface of cultured epithelial cells. We propose that the unique features of MYO3A, enhanced motor activity, and an extended tail with tail actin-binding motif, allow it to play an important role in stable actin protrusion length and ultrastructure maintenance. PMID:27582493
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Davies, Kerrie A; Ye, Weimin; Giblin-Davis, Robin M; Taylor, Gary S; Hodda, Mike; Thomas, W Kelley
2014-08-26
Fergusobia tumifaciens (Currie 1937) Wachek 1955, the type species for the genus Fergusobia, is re-described from specimens collected from 'leafy' leaf bud galls on Eucalyptus bridgesiana near Albury in New South Wales, Australia. It is morphologically characterized by the combination of an open C-shaped parthenogenetic female with a small broadly conoid tail, a C-shaped infective female with a bluntly rounded tail tip, and an arcuate to J-shaped male with angular spicules, not heavily sclerotised, and short to mid-length peloderan bursa. Two new species of Fergusobia, collected from 'leafy' leaf bud galls on, respectively, Eucalyptus planchoniana in Queensland, and E. viminalis in South Australia, Australia, are described. Fergusobia planchonianae Davies n. sp. is characterised by the combination of a C-shaped parthenogenetic female with a conoid tail, an arcuate infective female with an hemispherical tail tip, and an almost straight to arcuate to C-shaped male with an angular spicule, a long peloderan bursa and a narrow tail. Fergusobia viminalisae Davies n. sp. is characterised by the combination of an open C-shaped parthenogenetic female with a broadly conoid tail, a C-shaped infective female with a bluntly rounded tail tip, and an arcuate to J-shaped male with an angular (not heavily sclerotised) spicule and short to mid-length peloderan bursa. The shield morphologies of the fly larvae associated with the 'leafy' leaf bud galls and their possible relationships are outlined. Possible evolutionary relationships of the Fergusobia nematodes from these galls are discussed, considering their morphology, DNA sequences, and the relationships of the associated Fergusonina flies and host plants.
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The tail sheath structure of bacteriophage T4: a molecular machine for infecting bacteria
DOE Office of Scientific and Technical Information (OSTI.GOV)
Aksyuk, Anastasia A.; Leiman, Petr G.; Kurochkina, Lidia P.
2009-07-22
The contractile tail of bacteriophage T4 is a molecular machine that facilitates very high viral infection efficiency. Its major component is a tail sheath, which contracts during infection to less than half of its initial length. The sheath consists of 138 copies of the tail sheath protein, gene product (gp) 18, which surrounds the central non-contractile tail tube. The contraction of the sheath drives the tail tube through the outer membrane, creating a channel for the viral genome delivery. A crystal structure of about three quarters of gp18 has been determined and was fitted into cryo-electron microscopy reconstructions of themore » tail sheath before and after contraction. It was shown that during contraction, gp18 subunits slide over each other with no apparent change in their structure.« less
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Cranio-dirachischisis totalis in cephalothoracopagus twins.
Ferm, V H
1978-04-01
A set of conjoined 13-day-old male hamster twins is described. The twins were joined at the head and thorax. The brain was exencephalic and the neural plate was completely open throughout its length. The notochord was duplicated throughout its entire length. Partial twinning of the neural plate as indicated by histologic reconstruction is suggested with fusion or non-separation of the neural plates in the medial alar wing area. There was complete separation of the neural plates together with duplication of the lower extremities and tails in the caudal region of this specimen.
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Animal-Based Measures to Assess the Welfare of Extensively Managed Ewes
Hemsworth, Paul; Doyle, Rebecca
2017-01-01
Simple Summary The aim of this study was to assess the reliability and practicality of 10 animal-based welfare measures for extensively managed ewes, which were derived from the scientific literature, previous welfare protocols and through consultation with veterinarians and animal welfare scientists. Measures were examined on 100 Merino ewes, which were individually identified and repeatedly examined at mid-pregnancy, mid-lactation and weaning. Body condition score, fleece condition, skin lesions, tail length, dag score and lameness are proposed for on-farm use in welfare assessments of extensive sheep production systems. These six welfare measures, which address the main welfare concerns for extensively managed ewes, can be reliably and feasibly measured in the field. Abstract The reliability and feasibility of 10 animal-based measures of ewe welfare were examined for use in extensive sheep production systems. Measures were: Body condition score (BCS), rumen fill, fleece cleanliness, fleece condition, skin lesions, tail length, dag score, foot-wall integrity, hoof overgrowth and lameness, and all were examined on 100 Merino ewes (aged 2–4 years) during mid-pregnancy, mid-lactation and weaning by a pool of nine trained observers. The measures of BCS, fleece condition, skin lesions, tail length, dag score and lameness were deemed to be reliable and feasible. All had good observer agreement, as determined by the percentage of agreement, Kendall’s coefficient of concordance (W) and Kappa (k) values. When combined, these nutritional and health measures provide a snapshot of the current welfare status of ewes, as well as evidencing previous or potential welfare issues. PMID:29295551
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González, R; Dinghi, P; Corio, C; Medina, A; Maggioni, M; Storero, L; Gosztonyi, A
2014-02-01
A genetic study to support morphometric analyses was used to improve the description and validate the Patagonian seahorse Hippocampus patagonicus (Syngnathidae) on the basis of a large number of specimens collected in the type locality (San Antonio Bay, Patagonia, Argentina). DNA sequence data (from the cytochrome b region of the mitochondrial genome) were used to differentiate this species from its relatives cited for the west Atlantic Ocean. Both phylogenetic and genetic distance analyses supported the hypothesis that H. patagonicus is a species clearly differentiated from others, in agreement with morphometric studies. Hippocampus patagonicus can be distinguished from Hippocampus erectus by the combination of the following morphometric characteristics: (1) in both sexes and all sizes of H. patagonicus, the snout length is always less than the postorbital length, whereas the snout length of H. erectus is not shorter than the postorbital length in the largest specimens; (2) in both sexes of H. patagonicus, the trunk length:total length (LTr :LT ) is lower than in H. erectus (in female H. patagonicus: 0·27-0·39, H. erectus: 0·36-0·40 and in male H. patagonicus: 0·24-0·34, H. erectus: 0·33-0·43) and (3) in both sexes, tail length:total length (LTa :LT ) in H. patagonicus is larger than in H. erectus (0·61-0·78 v. 0·54-0·64). © 2014 The Fisheries Society of the British Isles.
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The calculation of lateral stability with free controls
NASA Technical Reports Server (NTRS)
Mathias, Gotthold
1934-01-01
The discussion of the structural methods for obtaining lateral stability discloses the remarkable influence of the constant fuselage and wing proportions to the yawing moments. For the effectiveness of modifications in vertical tail surfaces and tail length, these quotas - little observed heretofore, in this connection - are decisive. This also applies to the amount of dihedral of the wing with regard to the roll stability of the complete wing already existing without angle of the dihedral.
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Association of Body Length with Ocular Parameters in Mice
Chakraborty, Ranjay; Park, Han na; Tan, Christopher C.; Weiss, Paul; Prunt, Megan C.; Pardue, Machelle T.
2017-01-01
Purpose To determine the association between changes in body length with ocular refraction, corneal radii, axial length, and lens thickness in two different mouse strains. Methods Body length, ocular refraction, corneal radii, axial length, and lens thickness were measured for two inbred mouse strains: 129S1/SvJ (n=7) and C57BL/6J (n=10) from 4 to 12 weeks of age. Body length, from tip of nose to base of tail was obtained using a digital camera. Biometric parameters, corneal radii and refractions were measured using spectral-domain optical coherence tomography, automated keratometry and infrared photorefraction, respectively. A mixed model ANOVA was performed to examine the changes in ocular parameters as a function of body length and strain in mice controlling for age, gender and weight over time. Results C57BL/6J mice had significantly longer body length (average body length at 10 weeks, 8.60 ± 0.06 cm) compared 129S1/SvJ mice (8.31 ± 0.05 cm) during development (p<0.001). C57BL/6J mice had significantly hyperopic refractions compared to 129S1/SvJ mice across age (mean refraction at 10 weeks, 129S1/SvJ: +0.99 ± 0.44 D versus C57BL/6J: +6.24 ± 0.38 D, p<0.001). Corneal radius of curvature, axial length and lens thickness (except 10 weeks lens thickness) were similar between the two strains throughout the measurement. In the mixed model ANOVA, changes in body length showed an independent and significant association with the changes in refraction (p=0.002) and corneal radii (p=0.016) for each mouse strain. No significant association was found between the changes in axial length (p=0.925) or lens thickness (p=0.973) as a function of body length and strain. Conclusions Changes in body length are significantly associated with the changes in ocular refraction and corneal radii in different mouse strains. Future studies are needed to determine if the association between body length and ocular refraction are related to changes in corneal curvature in mice. PMID:28005683
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Tikhonova, Irina G.; Ivetic, Aleksandar; Schu, Peter
2017-01-01
L-selectin regulates leukocyte adhesion and rolling along the endothelium. Proteins binding to the cytoplasmic tail of L-selectin regulate L-selectin functions. We used L-selectin cytoplasmic tail peptide pulldown assays combined with high sensitivity liquid chromatography/mass spectrometry to identify novel L-selectin tail-binding proteins. Incubation of the L-selectin tail with cell extracts from phorbol 12-myristate 13-acetate-stimulated Raw 264.7 macrophages resulted in the binding of μ1A of the clathrin-coated vesicle AP-1 complex. Furthermore, full-length GST-μ1A and the GST-μ1A C-terminal domain, but not the GST-μ1A N-terminal domain, bind to L-selectin tail peptide, and the intracellular pool of L-selectin colocalizes with AP-1 at the trans-Golgi network. We identified a novel basic protein motif consisting of a cluster of three dibasic residues (356RR357, 359KK360, and 362KK363) in the membrane-proximal domain of the L-selectin tail as well as a doublet of aspartic acid residues (369DD370) in the membrane-distal end of the L-selectin tail involved in μ1A binding. Stimulation of Raw 264.7 macrophages with PMA augmented the amount of μ1A associated with anti-L-selectin immunoprecipitates. However, full-length GST-μ1A did not bind to the phospho-L-selectin tail or phospho-mimetic S364D L-selectin tail. Accordingly, we propose that phosphorylation of μ1A is required for interaction with the L-selectin tail and that L-selectin tail phosphorylation may regulate this interaction in vivo. Molecular docking of the L-selectin tail to μ1A was used to identify the μ1A surface domain binding the L-selectin tail and to explain how phosphorylation of the L-selectin tail abrogates μ1A interaction. Our findings indicate that L-selectin is transported constitutively by the AP-1 complex, leading to the formation of a trans-Golgi network reserve pool and that phosphorylation of the L-selectin tail blocks AP-1-dependent retrograde transport of L-selectin. PMID:28235798
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Dib, Karim; Tikhonova, Irina G; Ivetic, Aleksandar; Schu, Peter
2017-04-21
L-selectin regulates leukocyte adhesion and rolling along the endothelium. Proteins binding to the cytoplasmic tail of L-selectin regulate L-selectin functions. We used L-selectin cytoplasmic tail peptide pulldown assays combined with high sensitivity liquid chromatography/mass spectrometry to identify novel L-selectin tail-binding proteins. Incubation of the L-selectin tail with cell extracts from phorbol 12-myristate 13-acetate-stimulated Raw 264.7 macrophages resulted in the binding of μ1A of the clathrin-coated vesicle AP-1 complex. Furthermore, full-length GST-μ1A and the GST-μ1A C-terminal domain, but not the GST-μ1A N-terminal domain, bind to L-selectin tail peptide, and the intracellular pool of L-selectin colocalizes with AP-1 at the trans -Golgi network. We identified a novel basic protein motif consisting of a cluster of three dibasic residues ( 356 RR 357 , 359 KK 360 , and 362 KK 363 ) in the membrane-proximal domain of the L-selectin tail as well as a doublet of aspartic acid residues ( 369 DD 370 ) in the membrane-distal end of the L-selectin tail involved in μ1A binding. Stimulation of Raw 264.7 macrophages with PMA augmented the amount of μ1A associated with anti-L-selectin immunoprecipitates. However, full-length GST-μ1A did not bind to the phospho-L-selectin tail or phospho-mimetic S364D L-selectin tail. Accordingly, we propose that phosphorylation of μ1A is required for interaction with the L-selectin tail and that L-selectin tail phosphorylation may regulate this interaction in vivo Molecular docking of the L-selectin tail to μ1A was used to identify the μ1A surface domain binding the L-selectin tail and to explain how phosphorylation of the L-selectin tail abrogates μ1A interaction. Our findings indicate that L-selectin is transported constitutively by the AP-1 complex, leading to the formation of a trans -Golgi network reserve pool and that phosphorylation of the L-selectin tail blocks AP-1-dependent retrograde transport of L-selectin. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
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Chang, Chia-Hao; Lin, Han-Yang; Jang-Liaw, Nian-Hong; Shao, Kwang-Tsao; Lin, Yeong-Shin; Ho, Hsuan-Ching
2013-06-01
The complete mitochondrial genome of the tiger tail seahorse was sequenced using a polymerase chain reaction-based method. The total length of mitochondrial DNA is 16,525 bp and includes 13 protein-coding genes, 2 ribosomal RNA, 22 transfer RNA genes, and a control region. The mitochondrial gene arrangement of the tiger tail seahorse is also matching the one observed in the most vertebrate creatures. Base composition of the genome is A (32.8%), T (29.8%), C (23.0%), and G (14.4%) with an A+T-rich hallmark as that of other vertebrate mitochondrial genomes.
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MARTINEZ, Josue G.; BOHN, Kirsten M.; CARROLL, Raymond J.
2013-01-01
We describe a new approach to analyze chirp syllables of free-tailed bats from two regions of Texas in which they are predominant: Austin and College Station. Our goal is to characterize any systematic regional differences in the mating chirps and assess whether individual bats have signature chirps. The data are analyzed by modeling spectrograms of the chirps as responses in a Bayesian functional mixed model. Given the variable chirp lengths, we compute the spectrograms on a relative time scale interpretable as the relative chirp position, using a variable window overlap based on chirp length. We use 2D wavelet transforms to capture correlation within the spectrogram in our modeling and obtain adaptive regularization of the estimates and inference for the regions-specific spectrograms. Our model includes random effect spectrograms at the bat level to account for correlation among chirps from the same bat, and to assess relative variability in chirp spectrograms within and between bats. The modeling of spectrograms using functional mixed models is a general approach for the analysis of replicated nonstationary time series, such as our acoustical signals, to relate aspects of the signals to various predictors, while accounting for between-signal structure. This can be done on raw spectrograms when all signals are of the same length, and can be done using spectrograms defined on a relative time scale for signals of variable length in settings where the idea of defining correspondence across signals based on relative position is sensible. PMID:23997376
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Comparative description of PFAA developmental toxicity: An update
The perfluoroalkyl acids (PFAAs) are a family of fluorocarbons consisting of a perfluorinated carbon tail (typically 4-12 carbons in length) and an acidic functional moiety, usually carboxylate or sulfonate. These compounds have excellent surface tension reducing properties and h...
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Interactions regulating the head-to-tail directed assembly of biological Janus rods
DOE Office of Scientific and Technical Information (OSTI.GOV)
Greene, A. C.; Bachand, M.; Gomez, A.
We can generalize the directed, head-to-tail self-assembly of microtubule filaments in the context of Janus colloidal rods. Specifically, their assembly at the tens of micron-length scale involves a careful balance between long-range electrostatic repulsion and short-range attractive forces. We show that the addition of counterion salts increases the rate of directed assembly by screening the electrostatic forces and enhancing the effectiveness of short-range interactions at the microtubule ends.
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Interactions regulating the head-to-tail directed assembly of biological Janus rods
Greene, A. C.; Bachand, M.; Gomez, A.; ...
2017-03-31
We can generalize the directed, head-to-tail self-assembly of microtubule filaments in the context of Janus colloidal rods. Specifically, their assembly at the tens of micron-length scale involves a careful balance between long-range electrostatic repulsion and short-range attractive forces. We show that the addition of counterion salts increases the rate of directed assembly by screening the electrostatic forces and enhancing the effectiveness of short-range interactions at the microtubule ends.
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NASA Astrophysics Data System (ADS)
McGovern, Scott; Alici, Gursel; Truong, Van-Tan; Spinks, Geoffrey
2009-09-01
This paper presents the development of an autonomously powered and controlled robotic fish that incorporates an active flexural joint tail fin, activated through conducting polymer actuators based on polypyrrole (PPy). The novel electromaterial muscle oscillator (NEMO) tail fin assembly on the fish could be controlled wirelessly in real time by varying the frequency and duty cycle of the voltage signal supplied to the PPy bending-type actuators. Directional control was achieved by altering the duty cycle of the voltage input to the NEMO tail fin, which shifted the axis of oscillation and enabled turning of the robotic fish. At low speeds, the robotic fish had a turning circle as small as 15 cm (or 1.1 body lengths) in radius. The highest speed of the fish robot was estimated to be approximately 33 mm s-1 (or 0.25 body lengths s-1) and was achieved with a flapping frequency of 0.6-0.8 Hz which also corresponded with the most hydrodynamically efficient mode for tail fin operation. This speed is approximately ten times faster than those for any previously reported artificial muscle based device that also offers real-time speed and directional control. This study contributes to previously published studies on bio-inspired functional devices, demonstrating that electroactive polymer actuators can be real alternatives to conventional means of actuation such as electric motors.
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Handoo, Zafar A.; Huettel, Robin N.; Golden, A. Morgan
1993-01-01
Meloidogyne sasseri n. sp. is described and illustrated from American beachgrass (Ammophila breviliffulata) originally collected from Henlopen State Park and Fenwick Island near the Maryland state line in Delaware, United States (6). Its relationship to M. graminis, M. spartinae, and M. californiensis is discussed. Primary distinctive characters of the female perineal pattern were a high to rounded arch with shoulders, widely spaced lateral lines interrupting transverse striations, a sunken vulva and anus, and coarse broken striae around the anal area. Second-stage juvenile body length was 554 μm (470-550), stylet length 14 μm (13-14.5), tail length 93 μm (83-115), tapering to a finely rounded terminus. Male stylet length 20 μm (19-21.5), spicule length 33 μm (30-36). Scanning electron microscope observations provided additional details of perineal patterns and face views of the female, male, and J2 head. Wheat, rice, oat, Ammophila sp., Panicum sp., bermudagrass, zoysiagrass and St. Augustinegrass were tested as hosts. Distribution of the species was the coasts of Delaware and Maryland. The common name "beachgrass root-knot" is proposed for M. sasseri n. sp. PMID:19279820
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Standardization of methods of expressing lengths and weights of fish
Hile, Ralph
1948-01-01
Fishery workers in the United States and Canada are unable to think readily in terms of the metric system of weights and measurements. Even long experience does not make it possible to form a clear idea as to the actual size of fish for which lengths and weights are given in metric units, without first converting to the English system. A more general adoption of the English system of weights and measurements in fishery work is recommended. The use of English units exclusively is suggested for articles of a popular or semi-popular nature, but in more formal publications the key information, at least, should be recorded in both systems. In highly technical papers metric units alone may prove satisfactory. Agreement is also lacking as to which length measurement of fish is suited best for uniform adoption. The total length is recommended here for the reason that it is the only measurement that includes all of the fish. This length is defined as the distance from the tip of the head (jaws closed) to the tip of the tail with the lobes compressed so as to give the maximum possible measurement.
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The effect of flash-freezing temperature on stallion sperm DNA structure.
Serafini, R; Varner, D D; Bissett, W; Blanchard, T L; Teague, S R; Love, C C
2017-06-01
The effect of flash-freezing storage temperature on stallion sperm DNA has not been evaluated. Commonly, sperm are flash-frozen at various temperatures to preserve sperm DNA prior to analysis. It is unclear whether the temperature at which sperm are frozen and stored may affect the results of DNA assays. In this study, the neutral comet assay was used to evaluate the effect of flash-freezing storage temperature (freezer [-60 °C], dry ice [-78.5 °C], liquid nitrogen [-196 °C]) compared to fresh sperm DNA structure. In addition, intra- and inter-assay and intra- and inter-stallion variabilities were determined. All comet tail measures were higher following any flash-freezing method, as compared to fresh sperm DNA (P < 0.05), with no difference among flash-frozen treatments (P > 0.05). For most comet variables, intra- and inter-assay variabilities were <10%. Intra- and inter-stallion variabilities revealed that comet head length (HL) and width (CW) were less variable as compared to comet tail values, i.e., % comet tail DNA (T-DNA), tail length (TL), tail moment (OTM), and tail migration (TM). Certain comet tail values in fresh (% T-DNA, and OTM) and flash-frozen sperm (OTM, % T-DNA, TL, and TM) were correlated to the Sperm Chromatin Structure Assay (SCSA) variable, COMP-α t . The comet tail measures were negatively correlated to % morphologically normal sperm (P < 0.05) and positively correlated to % abnormal heads and premature germ cells (P < 0.05). Variables COMP-α t and % total sperm motility were not correlated to any morphologic sperm feature in this group of stallions (P > 0.05). While significant differences in the structure of the sperm DNA were identified in the flash-frozen as compared to the fresh sperm DNA with the neutral comet assay, it cannot be assumed that these changes are fertility limiting. Copyright © 2017. Published by Elsevier Inc.
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Al-Dulaymi, Mays A; Chitanda, Jackson M; Mohammed-Saeid, Waleed; Araghi, Hessamaddin Younesi; Verrall, Ronald E; Grochulski, Pawel; Badea, Ildiko
2016-09-01
The aim of this work was to elucidate the structure-activity relationship of new peptide-modified gemini surfactant-based carriers. Glycyl-lysine modified gemini surfactants that differ in the length and degree of unsaturation of their alkyl tail were used to engineer DNA nano-assemblies. To probe the optimal nitrogen to phosphate (N/P) ratio in the presence of helper lipid, in vitro gene expression and cell toxicity measurements were carried out. Characterization of the nano-assemblies was accomplished by measuring the particle size and surface charge. Morphological characteristics and lipid organization were studied by small angle X-ray scattering technique. Lipid monolayers were studied using a Langmuir-Blodgett trough. The highest activity of glycyl-lysine modified gemini surfactants was observed with the 16-carbon tail compound at 2.5 N/P ratio, showing a 5- to 10-fold increase in the level of reporter protein compared to the 12 and 18:1 carbon tail compounds. This ratio is significantly lower compared to the previously studied gemini surfactants with alkyl or amino- spacers. In addition, the 16-carbon tail compound exhibited the highest cell viability (85%). This high efficiency is attributed to the lowest critical micelle concentration of the 16-tail gemini surfactant and a balanced packing of the nanoparticles by mixing a saturated and unsaturated lipid together. At the optimal N/P ratio, all nanoparticles exhibited an inverted hexagonal lipid assembly. The results show that the length and nature of the tail of the gemini surfactants play an important role in determining the transgene efficiency of the delivery system. We demonstrated here that the interplay between the headgroup and the nature of tail is specific to each series, thus in the process of rational design, the contribution of the latter should be assessed in the appropriate context.
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Internal vs Fishhook Hairpin DNA: Unzipping Locations and Mechanisms in the α-Hemolysin Nanopore
2015-01-01
Studies on the interaction of hairpin DNA with the α-hemolysin (α-HL) nanopore have determined hairpin unzipping kinetics, thermodynamics, and sequence-dependent DNA/protein interactions. Missing from these results is a systematic study comparing the unzipping process for fishhook (one-tail) vs internal (two-tail) hairpins when they are electrophoretically driven from the cis to the trans side of α-HL via a 30-mer single-stranded tail. In the current studies, fishhook hairpins showed long unzipping times with one deep blockage current level. In contrast, the internal hairpins demonstrated relatively fast unzipping and a characteristic pulse-like current pattern. These differences were further explored with respect to stem length and sequence context. Further, a series of internal hairpins with asymmetric tails were studied, for which it was determined that a second tail longer than 12 nucleotides results in internal hairpin unzipping behavior, while tail lengths of 6 nucleotides behaved like fishhook hairpins. Interestingly, these studies were able to resolve a current difference of ∼6% between hairpin DNA immobilized in the nanopore waiting to unzip vs the translocating unzipped DNA, with the latter showing a deeper current blockage level. This demonstration of different currents for immobilized and translocating DNA has not been described previously. These results were interpreted as fishhook hairpins unzipping inside the vestibule, while the internal hairpins unzip outside the vestibule of α-HL. Lastly, we used this knowledge to study the unzipping of a long double-stranded DNA (>50 base pairs) outside the vestibule of α-HL. The conclusions drawn from these studies are anticipated to be beneficial in future application of nanopore analysis of nucleic acids. PMID:25333648
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Simulation study of entropy production in the one-dimensional Vlasov system
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dai, Zongliang, E-mail: liangliang1223@gmail.com; Wang, Shaojie
2016-07-15
The coarse-grain averaged distribution function of the one-dimensional Vlasov system is obtained by numerical simulation. The entropy productions in cases of the random field, the linear Landau damping, and the bump-on-tail instability are computed with the coarse-grain averaged distribution function. The computed entropy production is converged with increasing length of coarse-grain average. When the distribution function differs slightly from a Maxwellian distribution, the converged value agrees with the result computed by using the definition of thermodynamic entropy. The length of the coarse-grain average to compute the coarse-grain averaged distribution function is discussed.
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Zograf, Julia; Trebukhova, Yulia; Pavlyuk, Olga
2015-01-16
In deep-sea sediments from the Sea of Japan, two new species, Halichoanolaimus brandtae sp. n. and Siphonolaimus japonicus sp. n., were found and described. Siphonolaimus japonicus sp. n. is characterized by having short anterior sensillae, body length of 3670-4500 μm, buccal cavity with axial spear, and length of the spicules. Halichoanolaimus brandtae sp.n is characterized by the number of amphideal rings, long spicules, five precloacal supplements and by having a long cylindrical part of the tail. Keys to species level are provided.
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Variation among Populations of Belonolaimus longicaudatus.
Robbins, R T; Hirschmann, H
1974-04-01
Three North Carolina populations of Belonolairnus longicaudatus differed significantly from three Georgia populations in stylet measurements, the c ratio, the distance of the excretory pore from the anterior end for both sexes; the a ratio for females only; and the total body length, tail length, and spicule length for males only. The Georgia nematodes were stouter, and the females possessed sclerotized vaginal pieces. The distal portion of the spicules of North Carolina males had an indentation and hump lacking in those of the Georgia males. The haploid number of chromosomes was eight for males from all populations of B. longicaudatus and a North Carolina population of B. maritimus. Interpopulation matings of the Tarboro, N.C. and Tifton, Ga. populations indicated that the offspring produced were infertile. Morphological differences and reproductive isolation suggest that the North Carolina and the Georgia populations belong to different species.
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Unifying Rules for Aquatic Locomotion
NASA Astrophysics Data System (ADS)
Saadat, Mehdi; Domel, August; di Santo, Valentina; Lauder, George; Haj-Hariri, Hossein
2016-11-01
Strouhal number, St (=fA/U) , a scaling parameter that relates speed, U, to the tail-beat frequency, f, and tail-beat amplitude, A, has been used many times to describe animal locomotion. It has been observed that swimming animals cruise at 0.2 <=St <=0.4. Using simple dimensional and scaling analyses supported by new experimental evidence of a self-propelled fish-like swimmer, we show that when cruising at minimum hydrodynamic input power, St is predetermined, and is only a function of the shape, i.e. drag coefficient and area. The narrow range for St, 0.2-0.4, has been previously associated with optimal propulsive efficiency. However, St alone is insufficient for deciding optimal motion. We show that hydrodynamic input power (energy usage to propel over a unit distance) in fish locomotion is minimized at all cruising speeds when A* (= A/L), a scaling parameter that relates tail-beat amplitude, A, to the length of the swimmer, L, is constrained to a narrow range of 0.15-0.25. Our analysis proposes a constraint on A*, in addition to the previously found constraint on St, to fully describe the optimal swimming gait for fast swimmers. A survey of kinematics for dolphin, as well as new data for trout, show that the range of St and A* for fast swimmers indeed are constrained to 0.2-0.4 and 0.15-0.25, respectively. Our findings provide physical explanation as to why fast aquatic swimmers cruise with relatively constant tail-beat amplitude at approximately 20 percent of body length, while their swimming speed is linearly correlated with their tail-beat frequency.
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Li, Xinlei; Liu, Yongqing; Haas, Thomas A
2014-12-01
We previously found that peptides derived from the full length of integrin αIIb and αV cytoplasmic tails inhibited their parent integrin activation, respectively. Here we showed that the cell-permeable peptides corresponding to the conserved central turn motif within αIIb and αV cytoplasmic tails, myr-KRNRPPLEED (αIIb peptide) and myr-KRVRPPQEEQ (αV peptide), similarly inhibited both αIIb and αV integrin activation. Pre-treatment with αIIb or αV peptides inhibited Mn(2+)-activated αIIbβ3 binding to soluble fibrinogen as well as the binding of αIIbβ3-expressing Chinese Hamster Ovary cells to immobilized fibrinogen. Our turn peptides also inhibited adhesion of two breast cancer cell lines (MDA-MB-435 and MCF7) to αV ligand vitronectin. These results suggest that αIIb and αV peptides share a same mechanism in regulating integrin function. Using αIIb peptide as a model, we found that replacement of RPP with AAA significantly attenuated the inhibitory activity of αIIb peptide. Furthermore, we found that αIIb peptide specifically bound to β-tubulin in cells. Our work suggests that the central motif of α tails is an anchoring point for cytoskeletons during integrin activation and integrin-mediated cell adhesion, and its function depends on the turn structure at RPP. However, post-treatment of peptides derived from the full-length tail or from the turn motif did not reverse αIIb and αV integrin activation. Copyright © 2014 Elsevier Inc. All rights reserved.
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Tool for Crimping Flexible Circuit Leads
NASA Technical Reports Server (NTRS)
Hulse, Aaron; Diftler, Myron A.
2009-01-01
A hand tool has been developed for crimping leads in flexible tails that are parts of some electronic circuits -- especially some sensor circuits. The tool is used to cut the tails to desired lengths and attach solder tabs to the leads. For tailoring small numbers of circuits for special applications, this hand tool is a less expensive alternative to a commercially available automated crimping tool. The crimping tool consists of an off-the-shelf hand crimping tool plus a specialized crimping insert designed specifically for the intended application.
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Magnetically Driven Swimming of Nanoscale Colloidal Assemblies
NASA Astrophysics Data System (ADS)
Breidenich, Jennifer; Benkoski, Jason; Baird, Lance; Deacon, Ryan; Land, H. Bruce; Hayes, Allen; Keng, Pei; Pyun, Jeffrey
2009-03-01
At microscopic length scales, locomotion can only be generated through asymmetric conformation changes, such as the undulating flagellum employed by protozoa. This simple yet elegant design is optimized according to the dueling needs of miniaturization and the fluid dynamics of the low Reynolds number environment. In this study, we fabricate nanoscale colloidal assemblies that mimic the head + tail structure of flagellates. The assemblies consist of two types of magnetic colloids: 25 nm polystyrene-coated Co nanoparticles, and 250 nm polyethylene glycol coated magnetite nanoparticles. When mixed together in N-dimethylformamide, the Co nanoparticles assemble into flexible, segmented chains ranging in length from 1 - 5 μm. These chains then attach at one end to the larger magnetic beads due to magnetic attraction. This head + tail structure aligns with an external uniform magnetic field and is actuated by an oscillating transverse field. We examine the effects of Co nanoparticle concentration, magnetite bead concentration, magnetic field strength, and oscillation frequency on the formation of swimmers and the speed of locomotion.
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Evolutionary dynamics of selfish DNA explains the abundance distribution of genomic subsequences
Sheinman, Michael; Ramisch, Anna; Massip, Florian; Arndt, Peter F.
2016-01-01
Since the sequencing of large genomes, many statistical features of their sequences have been found. One intriguing feature is that certain subsequences are much more abundant than others. In fact, abundances of subsequences of a given length are distributed with a scale-free power-law tail, resembling properties of human texts, such as Zipf’s law. Despite recent efforts, the understanding of this phenomenon is still lacking. Here we find that selfish DNA elements, such as those belonging to the Alu family of repeats, dominate the power-law tail. Interestingly, for the Alu elements the power-law exponent increases with the length of the considered subsequences. Motivated by these observations, we develop a model of selfish DNA expansion. The predictions of this model qualitatively and quantitatively agree with the empirical observations. This allows us to estimate parameters for the process of selfish DNA spreading in a genome during its evolution. The obtained results shed light on how evolution of selfish DNA elements shapes non-trivial statistical properties of genomes. PMID:27488939
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NASA Astrophysics Data System (ADS)
Beheshtipour, Saleheh; Safari, Ebrahim; Majdabadi, Abbas; Silakhori, Kaveh
2018-02-01
Transversely Excited Atmospheric (TEA) CO2 laser pulses were used in order to generate an optical breakdown in a variety of mono- and polyatomic molecules using different focusing powers. The dependence of the spark kernel geometry and the transmitted pulse shapes on the focusing power as well as the pressure, molecular weight, and ionization energy of the gases was investigated in detail. Partial removal of the transmitted pulse tail in the 0.05-2.6 μs range together with shortened spikes in the 10-60 ns range has been observed by applying a 2.5 cm focal length lens for all the gases. At higher focal lengths, this effect is only incompletely observed for He gas. Spatial-temporal analyses of the laser beams and the relevant plasma plumes indicate that this behavior is due to the drop in the plasma density below the critical level, before the laser pulse tail is completed.
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Shen, Xuefeng; Mao, Wenting; Ma, Yanhang; Peng, Honggen; Xu, Dongdong; Wu, Peng; Han, Lu; Che, Shunai
2018-06-18
Mesoporous MFI zeolites (MMZs) have been constructed by using the surfactant-containing azobenzene segment in the hydrophobic tail. The cylindrical π-π stacking of azeobenzene groups is considered to be the key factor to form the ordered mesostructure through cooperative structural matching and the rearrangement of MFI frameworks. The mesostructure has been tuned from a disordered hierarchical arrangement into an ordered 2D square p4mm structure by changing the length of the alkyl chain between the diquaternary ammonium head group and azobenzene group. The geometric matching between the MFI zeolitic framework and the alkyl chain length plays an important role in the construction of the crystallographically correlated mesostructure with 2D square ordering. A combination of X-ray diffraction patterns and electron microscopy studies provides visible evidence for the mesostructural transformation from a short-range hexagonal or lamellar ordering to 2D square mesostructure. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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NASA Technical Reports Server (NTRS)
Barnhart, B.
1982-01-01
The influence of horizontal tail location on the rotational flow aerodynamics is discussed for a 1/6-scale general aviation airplane model. The model was tested using various horizontal tail positions, with both a high and a low-wing location and for each of two body lengths. Data were measured, using a rotary balance, over an angle-of-attack range of 8 to 90 deg, and for clockwise and counter-clockwise rotations covering an Omega b/2V range of 0 to 0.9.
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The fine structure of spermatozoa of Hydrolagus colliei (Chondrichthyes, Holocephali).
Stanley, H P
1983-05-01
The ultrastructure of spermatozoa in Hydrolagus colliei is described. Basic similarities of structure to the sperm of the related elasmobranch fish are noted. The most significant features of sperm structure in Hydrolagus that differ from those of elasmobranch fish occur in the tail. The axoneme is eccentrically located and forms a double helix with a single longitudinal column. A second longitudinal column is reduced to a short remnant at the base of the tail. Microtubules within the axoneme are also helically disposed, a feature that is consistent with the rotating motion of the sperm. Abundant glycogen reserves are stored along the length of the tail.
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Chawanji, A S; Hodgson, A N; Villet, M H
2005-08-01
Mature spermatozoa from four species of platypleurine cicadas (Albanycada albigera, Azanicada zuluensis, Platypleura capensis and P. hirtipennis) were examined by light and electron microscopy. The filiform sperm have a similar ultrastructure in all species but notable variations were found in sperm dimensions. All species produce more than one discrete length of nucleated, motile sperm, a form of polymorphism termed polymegaly. Polymegaly is expressed in two ways: sperm have bi- or trimodal head and tail lengths. The anterior parts of sperm heads are embedded in an elongate homogenous matrix forming a spermatodesm. The conical acrosome is deeply invaginated posteriorly, and sits on top of the nucleus. The acrosomal contents are differentiated internally with an electron-lucent central medulla and a denser cortex. The homogenously electron-dense nucleus is pointed anteriorly and is generally cylindrical, although posteriorly there is a lateral invagination that extends part-way along the nucleus. This invagination houses fine granular material of the centriolar adjunct. Vesicle-like elements that are associated with both the posterior nucleus and the centriolar adjunct are also found within the invagination. Immediately posterior of and adjoining the centriolar adjunct is a pair of mitochondrial derivatives that are elongated and extend for almost the entire length of the tail. The absence of accessory bodies in cicada sperm suggests that within the Cicadomorpha, the families Cicadidae and Cercopidae are closely affiliated.
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Kim, Jin Hee; Chung, Jae Seung; Lee, Ki-Young
2013-06-01
Ultrastructural characteristics of the germ cells and accessory cells in testis during spermatogenesis and taxonomic values of mature sperm morphology of Ruditapes philippinarum were investigated by the transmission electron microscope and scanning electron microscope observations. The testis is the diffuse organ that consists of branching acini containing developing germ cells and accessory cells associated with spermatogenesis. The morphology of the spermatozoon is of the primitive type and is somewhat different to those of other bivalves. The morphologies of the sperm nucleus type and the acrosome shape of this species have a cylinderical type and a modified cone shape, respectively. As some ultrastructural characteristics of the acrosomal vesicle, the peripheral parts of two basal rings show electron opaque part, while the apex part of the acrosome shows electron lucent part. These characteristics of sperm belong to the family Veneridae in the subclass Heterodonta, unlike a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part. In particular, a cylinder-like nucleus of the sperm is curved. The spermatozoon is approximately 48-51 μm in length, including a long acrosome (about 2.40 μm in length), a curved sperm nucleus (about 3.40 μm in length), and a tail flagellum. The axoneme of the sperm tail shows a 9+2 structure.
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A retrotransposable element from the mosquito Anopheles gambiae .
Besansky, N J
1990-01-01
A family of middle repetitive elements from the African malaria vector Anopheles gambiae is described. Approximately 100 copies of the element, designated T1Ag, are dispersed in the genome. Full-length elements are 4.6 kilobase pairs in length, but truncation of the 5' end is common. Nucleotide sequences of one full-length, two 5'-truncated, and two 5' ends of T1Ag elements were determined and aligned to define a consensus sequence. Sequence analysis revealed two long, overlapping open reading frames followed by a polyadenylation signal, AATAAA, and a tail consisting of tandem repetitions of the motif TGAAA. No direct or inverted long terminal repeats (LTRs) were detected. The first open reading frame, 442 amino acids in length, includes a domain resembling that of nucleic acid-binding proteins. The second open reading frame, 975 amino acids long, resembles the reverse transcriptases of a category of retrotransposable elements without LTRs, variously termed class II retrotransposons, class III elements or non-LTR retrotransposons. Similarity at the sequence and structural levels places T1Ag in this category. Images PMID:1689457
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Turbulence Hazard Metric Based on Peak Accelerations for Jetliner Passengers
NASA Technical Reports Server (NTRS)
Stewart, Eric C.
2005-01-01
Calculations are made of the approximate hazard due to peak normal accelerations of an airplane flying through a simulated vertical wind field associated with a convective frontal system. The calculations are based on a hazard metric developed from a systematic application of a generic math model to 1-cosine discrete gusts of various amplitudes and gust lengths. The math model simulates the three degree-of- freedom longitudinal rigid body motion to vertical gusts and includes (1) fuselage flexibility, (2) the lag in the downwash from the wing to the tail, (3) gradual lift effects, (4) a simplified autopilot, and (5) motion of an unrestrained passenger in the rear cabin. Airplane and passenger response contours are calculated for a matrix of gust amplitudes and gust lengths. The airplane response contours are used to develop an approximate hazard metric of peak normal accelerations as a function of gust amplitude and gust length. The hazard metric is then applied to a two-dimensional simulated vertical wind field of a convective frontal system. The variations of the hazard metric with gust length and airplane heading are demonstrated.
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Dependence of exponents on text length versus finite-size scaling for word-frequency distributions
NASA Astrophysics Data System (ADS)
Corral, Álvaro; Font-Clos, Francesc
2017-08-01
Some authors have recently argued that a finite-size scaling law for the text-length dependence of word-frequency distributions cannot be conceptually valid. Here we give solid quantitative evidence for the validity of this scaling law, using both careful statistical tests and analytical arguments based on the generalized central-limit theorem applied to the moments of the distribution (and obtaining a novel derivation of Heaps' law as a by-product). We also find that the picture of word-frequency distributions with power-law exponents that decrease with text length [X. Yan and P. Minnhagen, Physica A 444, 828 (2016), 10.1016/j.physa.2015.10.082] does not stand with rigorous statistical analysis. Instead, we show that the distributions are perfectly described by power-law tails with stable exponents, whose values are close to 2, in agreement with the classical Zipf's law. Some misconceptions about scaling are also clarified.
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NASA Technical Reports Server (NTRS)
Whitlow, J. B., Jr.
1976-01-01
Sideline noise and takeoff field length were varied for two types of Mach 2.32 cruise airplane to determine their effect on engine cycle selection. One of these airplanes was the NASA/Langley-LTV arrow wing while the other was a Boeing modified delta-plus-tail derived from the earlier 2707-300 concept. Advanced variable cycle engines were considered. A more conventional advanced low bypass turbofan engine was used as a baseline for comparison. Appropriate exhaust nozzle modifications were assumed, where needed, to allow all engines to receive either an inherent co-annular or annular jet noise suppression benefit. All the VCE's out-performed the baseline engine by substantial margins in a design range comparison, regardless of airplane choice or takeoff restrictions. The choice among the three VCE's considered, however, depends on the field length, noise level, and airplane selected.
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Mori, Tsukasa; Yanagisawa, Yukio; Kitani, Yoichiro; Yamamoto, Goshi; Goto-Inoue, Naoko; Kimura, Tadashi; Kashiwagi, Keiko; Kashiwagi, Akihiko
2017-11-15
Predator-induced phenotypic plasticity is the ability of prey to adapt to their native predator. However, owing to environmental changes, encounters with unknown predators are inevitable. Therefore, study of prey and non-native predator interaction will reveal the primary stages of adaptive strategies in prey-predator interactions in the context of evolutionary processes. Here, Xenopus tadpoles exposed to a non-native predator, a larval salamander, showed a significant increase in body weight and tail length to body length ratio. The T max 2 test indicated a significant enhancement of the tail muscle and decrease in the relative ventral fin height in tadpoles exposed to predation risk, leading to significantly higher average swimming speeds. The analysis of muscle-related metabolites revealed that sarcosine increased significantly in tadpoles exposed to non-native predators. Multiple linear regression analysis of the fast-start swimming pattern showed that the fast-start swimming speed was determined by the time required for a tadpole to bend its body away from the threat (C-start) and the angle at which it was bent. In conclusion, morphological changes in tadpoles were functionally adaptive and induced by survival behaviors of Xenopus tadpoles against non-native predators. © 2017. Published by The Company of Biologists Ltd.
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Multivariate analysis of sexual size dimorphism in local turkeys (Meleagris gallopavo) in Nigeria.
Ajayi, Oyeyemi O; Yakubu, Abdulmojeed; Jayeola, Oluwaseun O; Imumorin, Ikhide G; Takeet, Michael I; Ozoje, Michael O; Ikeobi, Christian O N; Peters, Sunday O
2012-06-01
Sexual size dimorphism is a key evolutionary feature that can lead to important biological insights. To improve methods of sexing live birds in the field, we assessed sexual size dimorphism in Nigerian local turkeys (Meleagris gallopavo) using multivariate techniques. Measurements were taken on 125 twenty-week-old birds reared under the intensive management system. The body parameters measured were body weight, body length, breast girth, thigh length, shank length, keel length, wing length and wing span. Univariate analysis revealed that toms (males) had significantly (P < 0.05) higher mean values than hens (females) in all the measured traits. Positive phenotypic correlations between body weight and body measurements ranged from 0.445 to 0.821 in toms and 0.053-0.660 in hens, respectively. Three principal components (PC1, PC2 and PC3) were extracted in toms, each accounting for 63.70%, 19.42% and 5.72% of the total variance, respectively. However, four principal components (PC1, PC2, PC3 and PC4) were extracted in hens, which explained 54.03%, 15.29%, 11.68% and 6.95%, respectively of the generalised variance. A stepwise discriminant function analysis of the eight morphological traits indicated that body weight, body length, tail length and wing span were the most discriminating variables in separating the sexes. The single discriminant function obtained was able to correctly classify 100% of the birds into their source population. The results obtained from the present study could aid future management decisions, ecological studies and conservation of local turkeys in a developing economy.
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Scaling in Free-Swimming Fish and Implications for Measuring Size-at-Time in the Wild
Broell, Franziska; Taggart, Christopher T.
2015-01-01
This study was motivated by the need to measure size-at-age, and thus growth rate, in fish in the wild. We postulated that this could be achieved using accelerometer tags based first on early isometric scaling models that hypothesize that similar animals should move at the same speed with a stroke frequency that scales with length-1, and second on observations that the speed of primarily air-breathing free-swimming animals, presumably swimming ‘efficiently’, is independent of size, confirming that stroke frequency scales as length-1. However, such scaling relations between size and swimming parameters for fish remain mostly theoretical. Based on free-swimming saithe and sturgeon tagged with accelerometers, we introduce a species-specific scaling relationship between dominant tail beat frequency (TBF) and fork length. Dominant TBF was proportional to length-1 (r2 = 0.73, n = 40), and estimated swimming speed within species was independent of length. Similar scaling relations accrued in relation to body mass-0.29. We demonstrate that the dominant TBF can be used to estimate size-at-time and that accelerometer tags with onboard processing may be able to provide size-at-time estimates among free-swimming fish and thus the estimation of growth rate (change in size-at-time) in the wild. PMID:26673777
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A new species of seahorse (Teleostei: Syngnathidae) from the South China Sea.
Zhang, Yan-Hong; Qin, Geng; Wang, Xin; Lin, Qiang
2016-09-23
A new species of seahorse, Hippocampus casscsio sp. nov. was collected over shallow seagrass beds in Beibu Bay, China. This species is diagnosed from all other seahorse species by morphological characters, including the lower number of tail rings (35); 15 pectoral-fin rays; 16 dorsal-fin rays; a rounded nuchal plate without a raised coronet; a snout length 30% head length; two cheek spines and a dark brown coloration. In addition, molecular analysis showed all individuals of the new species clustering together suggesting a monophyletic lineage. This combined analysis supports the distinctness of H. casscsio sp. nov. as a new species, which is described herein.
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Convex hulls of random walks in higher dimensions: A large-deviation study
NASA Astrophysics Data System (ADS)
Schawe, Hendrik; Hartmann, Alexander K.; Majumdar, Satya N.
2017-12-01
The distribution of the hypervolume V and surface ∂ V of convex hulls of (multiple) random walks in higher dimensions are determined numerically, especially containing probabilities far smaller than P =10-1000 to estimate large deviation properties. For arbitrary dimensions and large walk lengths T , we suggest a scaling behavior of the distribution with the length of the walk T similar to the two-dimensional case and behavior of the distributions in the tails. We underpin both with numerical data in d =3 and d =4 dimensions. Further, we confirm the analytically known means of those distributions and calculate their variances for large T .
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Zapata, Lina M; Bock, Brian C; Orozco, Luz Yaneth; Palacio, Jaime A
2016-05-01
Trachemys callirostris is a turtle species endemic to northern South America. In northern Colombia it occurs in the middle and lower Magdalena River drainage and its principal tributaries (lower Cauca and San Jorge rivers) and in other minor drainages such as the lower Sinú River. In recent years, industrial, agricultural, and mining activities have altered natural habitats in Colombia where this species occurs, and many of the pollutants released there are known to induce genetic alterations in wildlife species. The micronucleus test and comet assay are two of the most widely used methods to characterize DNA damage induced by physical and chemical agents in wildlife species, but have not been employed previously for genotoxic evaluations in T. callirostris. The goal of this study was to optimize these genotoxic biomarkers for T. callirostris erythrocytes in order to establish levels of DNA damage in this species and thereby evaluate its potential as a sentinel species for monitoring genotoxic effects in freshwater environments in northern Colombia. Both genotoxic techniques were applied on peripheral blood erythrocytes from 20 captive-reared T. callirostris individuals as a negative control, as well as from samples obtained from 49 individuals collected in Magangué (Magdalena River drainage) and 24 individuals collected in Lorica (Sinú River drainage) in northern Colombia. Negative control individuals exhibited a baseline frequency of micronuclei of 0.78±0.58 and baseline values for comet tail length and tail moment of 3.34±0.24µm and 10.70±5.5, respectively. In contrast, samples from both field sites exhibited significantly greater evidence of genotoxic effects for both tests. The mean MN frequencies in the samples from Magangué and Lorica were 8.04±7.08 and 12.19±12.94, respectively. The mean tail length for samples from Magangué and Lorica were 5.78±3.18 and 15.46±7.39, respectively. Finally, the mean tail moment for samples from Magangué and Lorica were 23.59±18.22 and 297.94±242.18, respectively. The frequency of micronuclei in the samples was positively related to comet tail length and tail moment. Thus, this study showed that both genotoxicity biomarkers may be applied to T. callirostris erythrocytes as a sentinel organism for assessing the effects of environmental pollutants in freshwater ecosystems in northern South America. Copyright © 2016 Elsevier Inc. All rights reserved.
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Chen, Gang; Qiu, Hong; Ke, Shan-Dong; Hu, Shao-Ming; Yu, Shi-Ying; Zou, Sheng-Quan
2013-01-01
AIM: To investigate the molecular mechanisms underlying the reversal effect of emodin on platinum resistance in hepatocellular carcinoma. METHODS: After the addition of 10 μmol/L emodin to HepG2/oxaliplatin (OXA) cells, the inhibition rate (IR), 50% inhibitory concentration (IC50) and reversal index (IC50 in experimental group/IC50 in control group) were calculated. For HepG2, HepG2/OXA, HepG2/OXA/T, each cell line was divided into a control group, OXA group, OXA + fibroblast growth factor 7 (FGF7) group and OXA + emodin group, and the final concentrations of FGF7, emodin and OXA in each group were 5 ng/mL, 10 μg/mL and 10 μmol/L, respectively. Single-cell gel electrophoresis was conducted to detect DNA damage, and the fibroblast growth factor receptor 2 (FGFR2), phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2) and excision repair cross-complementing gene 1 (ERCC1) protein expression levels in each group were examined by Western blotting. RESULTS: Compared with the IC50 of 120.78 μmol/L in HepG2/OXA cells, the IC50 decreased to 39.65 μmol/L after treatment with 10 μmol/L emodin; thus, the reversal index was 3.05. Compared with the control group, the tail length and Olive tail length in the OXA group, OXA + FGF7 group and OXA + emodin group were significantly increased, and the differences were statistically significant (P < 0.01). The tail length and Olive tail length were lower in the OXA + FGF7 group than in the OXA group, and this difference was also statistically significant. Compared with the OXA + FGF7 group, the tail extent, the Olive tail moment and the percentage of tail DNA were significantly increased in the OXA + emodin group, and these differences were statistically significant (P < 0.01). In comparison with its parental cell line HepG2, the HepG2/OXA cells demonstrated significantly increased FGFR2, p-ERK1/2 and ERCC1 expression levels, whereas the expression of all three molecules was significantly inhibited in HepG2/OXA/T cells, in which FGFR2 was silenced by FGFR2 shRNA. In the examined HepG2 cells, the FGFR2, p-ERK1/2 and ERCC1 expression levels demonstrated increasing trends in the OXA group and OXA + FGF7 group. Compared with the OXA group and OXA + FGF7 group, the FGFR2, p-ERK1/2, and ERCC1 expression levels were significantly lower in the OXA + emodin group, and these differences were statistically significant. In the HepG2/OXA/T cell line that was transfected with FGFR2 shRNA, the FGFR2, p-ERK1/2 and ERCC1 expression levels were significantly inhibited, but there were no significant differences in these expression levels among the OXA, OXA + FGF7 and OXA + emodin groups. CONCLUSION: Emodin markedly reversed OXA resistance by enhancing OXA DNA damage in HepG2/OXA cells, and the molecular mechanism was related to the inhibitory effect on ERCC1 expression being mediated by the FGFR2/ERK1/2 signaling pathway. PMID:23674849
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In vitro models of tail contraction and cytoplasmic streaming in amoeboid cells.
Janson, L W; Taylor, D L
1993-10-01
We have developed a reconstituted gel-sol and contractile model system that mimics the structure and dynamics found at the ectoplasm/endoplasm interface in the tails of many amoeboid cells. We tested the role of gel-sol transformations of the actin-based cytoskeleton in the regulation of contraction and in the generation of endoplasm from ectoplasm. In a model system with fully phosphorylated myosin II, we demonstrated that either decreasing the actin filament length distribution or decreasing the extent of actin filament cross-linking initiated both a weakening of the gel strength and contraction. However, streaming of the solated gel components occurred only under conditions where the length distribution of actin was decreased, causing a self-destruct process of continued solation and contraction of the gel. These results offer significant support that gel strength plays an important role in the regulation of actin/myosin II-based contractions of the tail cortex in many amoeboid cells as defined by the solation-contraction coupling hypothesis (Taylor, D. L., and M. Fechheimer. 1982. Phil. Trans. Soc. Lond. B. 299:185-197). The competing processes of solation and contraction of the gel would appear to be mutually exclusive. However, it is the temporal-spatial balance of the rate and extent of two stages of solation, coupled to contraction, that can explain the conversion of gelled ectoplasm in the tail to a solated endoplasm within the same small volume, generation of a force for the retraction of tails, maintenance of cell polarity, and creation of a positive hydrostatic pressure to push against the newly formed endoplasm. The mechanism of solation-contraction of cortical cytoplasm may be a general component of the normal movement of a variety of amoeboid cells and may also be a component of other contractile events such as cytokinesis.
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NASA Technical Reports Server (NTRS)
Cannon, Michael D.
1956-01-01
This paper contains tail and hull loads data obtained in an investigation of a l/15-scale model of the Goodyear XZP5K airship. Data are presented in the form of tabulated pressure coefficients over a pitch and yaw range of +/-20 deg and 0 deg to 30 deg respectively, with various rudder and elevator deflections. Two tail configurations of different plan forms were tested on the model. The investigation was conducted in the Langley full-scale tunnel at a Reynolds number of approximately 16.5 x 10(exp 6) based on hull length, which corresponds to a Mach number of about 0.12.
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Imaging the Sources and Full Extent of the Sodium Tail of the Planet Mercury
NASA Technical Reports Server (NTRS)
Baumgardner, Jeffrey; Wilson, Jody; Mendillo, Michael
2008-01-01
Observations of sodium emission from Mercury can be used to describe the spatial and temporal patterns of sources and sinks in the planet s surface-boundary-exosphere. We report on new data sets that provide the highest spatial resolution of source regions at polar latitudes, as well as the extraordinary length of a tail of escaping Na atoms. The tail s extent of approx.1.5 degrees (nearly 1400 Mercury radii) is driven by radiation pressure effects upon Na atoms sputtered from the surface in the previous approx.5 hours. Wide-angle filtered-imaging instruments are thus capable of studying the time history of sputtering processes of sodium and other species at Mercury from ground-based observatories in concert with upcoming satellite missions to the planet. Plasma tails produced by photo-ionization of Na and other gases in Mercury s neutral tails may be observable by in-situ instruments.
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Parolini, Marco; Romano, Andrea; Khoriauli, Lela; Nergadze, Solomon G.; Caprioli, Manuela; Rubolini, Diego; Santagostino, Marco; Saino, Nicola; Giulotto, Elena
2015-01-01
Telomeres are conserved DNA-protein structures at the termini of eukaryotic chromosomes which contribute to maintenance of genome integrity, and their shortening leads to cell senescence, with negative consequences for organismal functions. Because telomere erosion is influenced by extrinsic and endogenous factors, telomere dynamics may provide a mechanistic basis for evolutionary and physiological trade-offs. Yet, knowledge of fundamental aspects of telomere biology under natural selection regimes, including sex- and context-dependent variation in early-life, and the covariation between telomere dynamics and growth, is scant. In this study of barn swallows (Hirundo rustica) we investigated the sex-dependent telomere erosion during nestling period, and the covariation between relative telomere length and body and plumage growth. Finally, we tested whether any covariation between growth traits and relative telomere length depends on the social environment, as influenced by sibling sex ratio. Relative telomere length declined on average over the period of nestling maximal growth rate (between 7 and 16 days of age) and differently covaried with initial relative telomere length in either sex. The frequency distribution of changes in relative telomere length was bimodal, with most nestlings decreasing and some increasing relative telomere length, but none of the offspring traits predicted the a posteriori identified group to which individual nestlings belonged. Tail and wing length increased with relative telomere length, but more steeply in males than females, and this relationship held both at the within- and among-broods levels. Moreover, the increase in plumage phenotypic values was steeper when the sex ratio of an individual’s siblings was female-biased. Our study provides evidence for telomere shortening during early life according to subtly different dynamics in either sex. Furthermore, it shows that the positive covariation between growth and relative telomere length depends on sex as well as social environment, in terms of sibling sex ratio. PMID:26565632
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Ogawa, Takuya; Emi, Koh-Ichi; Koga, Kazushi; Yoshimura, Tohru; Hemmi, Hisashi
2016-06-01
Cis-prenyltransferase usually consecutively catalyzes the head-to-tail condensation reactions of isopentenyl diphosphate to allylic prenyl diphosphate in the production of (E,Z-mixed) polyprenyl diphosphate, which is the precursor of glycosyl carrier lipids. Some recently discovered homologs of the enzyme, however, catalyze the nonhead-to-tail condensation reactions between allylic prenyl diphosphates. In this study, we characterize a cis-prenyltransferase homolog from a methanogenic archaeon, Methanosarcina acetivorans, to obtain information on the biosynthesis of the glycosyl carrier lipids within it. This enzyme catalyzes both head-to-tail and nonhead-to-tail condensation reactions. The kinetic analysis shows that the main reaction of the enzyme is consecutive head-to-tail prenyl condensation reactions yielding polyprenyl diphosphates, while the chain lengths of the major products seem shorter than expected for the precursor of glycosyl carrier lipids. On the other hand, a subsidiary reaction of the enzyme, i.e., nonhead-to-tail condensation between dimethylallyl diphosphate and farnesyl diphosphate, gives a novel diterpenoid compound, geranyllavandulyl diphosphate. © 2016 Federation of European Biochemical Societies.
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Seasonal variations of arsenic in mussels Mytilus galloprovincialis
NASA Astrophysics Data System (ADS)
Klarić, Sanja; Pavičić-Hamer, Dijana; Lucu, Čedomil
2004-10-01
Total arsenic concentration in the edible part of mussels Mytilus galloprovincialis was evaluated seasonally in the coastal area of Rijeka Bay (North Adriatic Sea, Croatia). Sampling stations were located close to the City of Bakar with no industrial facilities (site 1), in the vicinity of the oil refinery and oil thermoelectric power plant (Urinj, site 2), and 4 miles away from the Plomin coal thermoelectric power plant (Brseč village, site 3). Additionally, the concentration of arsenic in the tail muscle of the lobster Nephrops norvegicus, collected in Rijeka Bay, was studied. During winter at sites 2 and 3, the total arsenic in the edible part of the mussels was 16.4 mg As/kg FW (FW=fresh weight) and 4.38 mg As/kg FW, respectively, and increased during springtime at site 2 (6.5 mg As/kg FW) compared to the rest of the year, when individual total arsenic concentration at all sites ranged from 1.7 to 3.7 mg As/kg FW. In the winter (sites 2 and 3) and springtime (site 2) there was no correlation between the length of the mussel shell and the arsenic concentration in the edible part of the mussels. In the other seasons, at sites 1, 2 and 3, there was a correlation between arsenic in the edible part of mussels and shell length in most cases (correlation coefficients r varied from 0.64 to 0.85; P <0.05 to P <0.01). Correlation between shell length (in the narrow range of shell lengths from 3.4 to 5.0 cm) and arsenic in the edible part of the mussels shows linearity with a high regression coefficient (r =0.914; P <0.001). The increase of arsenic in the mussels during winter and spring was suggested at least partially as a result of a low nutritional status, i.e. reduced weight of the mussels' edible part during winter. In addition, a linear relationship was found between body length and arsenic concentration in the tail muscle (mean 17.11±4.48 mg As/kg FW) of the Norway lobster.
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A 70 Kiloparsec X-Ray Tail in the Cluster A3627
NASA Technical Reports Server (NTRS)
Sun, M.; Jones, C.; Forman, W.; Nulsen, P. E. J.; Donahue, M.; Voit, G. M.
2006-01-01
We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of approx. 10. It is luminous (L(0.5-2keV) approx 1041 ergs/s), with a temperature of approx. 0.7 keV and an X-ray gas mass of approx 10(exp 9) solar masses (approx 10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, with this blue galaxy being converted into a gas-poor galaxy. Three X-ray point sources are detected in the axis of the tail, which may imply active star formation there. The straightness and narrowness of the tail also imply that the turbulence in the intracluster medium is not strong on scales of 20-70 kpc.
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Liu, Z Q; Jiao, D; Meyers, M A; Zhang, Z F
2015-04-01
Feather shaft, which is primarily featured by a cylinder filled with foam, possesses a unique combination of mechanical robustness and flexibility with a low density through natural evolution and selection. Here the hierarchical structures of peacock's tail coverts shaft and its components are systematically characterized from millimeter to nanometer length scales. The variations in constituent and geometry along the length are examined. The mechanical properties under both dry and wet conditions are investigated. The deformation and failure behaviors and involved strengthening, stiffening and toughening mechanisms are analyzed qualitatively and quantitatively and correlated to the structures. It is revealed that the properties of feather shaft and its components have been optimized through various structural adaptations. Synergetic strengthening and stiffening effects can be achieved in overall rachis owing to increased failure resistance. This study is expected to aid in deeper understandings on the ingenious structure-property design strategies developed by nature, and accordingly, provide useful inspiration for the development of high-performance synthetic foams and foam-filled materials. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Directional Stability of Towed Airplanes
NASA Technical Reports Server (NTRS)
Soehne, W.
1956-01-01
So far, very careful investigations have been made regarding the flight properties, in particular the static and dynamic stability, of engine-propelled aircraft and of untowed gliders. In contrast, almost no investigations exist regarding the stability of airplanes towed by a towline. Thus, the following report will aim at investigating the directional stability of the towed airplane and, particularly, at determining what parameters of the flight attitude and what configuration properties affect the stability. The most important parameters of the flight attitude are the dynamic pressure, the aerodynamic coefficients of the flight attitude, and the climbing angle. Among the configuration properties, the following exert the greatest influence on the stability: the tow-cable length, the tow-cable attachment point, the ratio of the wing loadings of the towing and the towed airplanes, the moments of inertia, and the wing dihedral of the towed airplane. In addition, the size and shape of the towed airplane vertical tail, the vertical tail length, and the fuselage configuration are decisive factors in determining the yawing moment and side force due to sideslip, respectively.
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NASA Astrophysics Data System (ADS)
Jin, L.; Meeks, J. L.; Hubbard, K. A.; Kurian, L. M.; Siegel, D. I.; Lautz, L. K.; Otz, M. H.
2007-12-01
Temporary storage of surface water at channel sides and pools significantly affects water and solute transport downstream in watersheds. Beavers, natural "stream channel engineers", build dams which obstruct stream flow and temporarily store water in small to large ponds within stream channels. These ponds substantially delay water movement and increase the water residence time in the system. To study how water and solutes move through these obstructed stream channels, we did multiple dye tracing tests at Cherry Creek, a main tributary to Red Canyon Creek (Wind River Range, Wyoming). First we surveyed beaver dam distributions in detail within the study reaches. We then introduced dyes four times from July 2nd to 6th, 2007 using a scale-up approach. The observation site was fixed at the mouth of Cherry Creek, and 1.5 grams of Rhodamine WT (RWT) dye was injected sequentially at upstream sites with increasing test reach length. The reach lengths scaled up from 500m to 2.5 km. A field fluorometer recorded RWT concentrations every 15 seconds. The results show non-linear decreases of the peak concentration of the dye tracing cloud as the reach scaled up. Also, the times to 1.) the arrivals of the leading edges (Tl), 2.) the peak concentrations (Tp) and 3.) the tailing edges (Tt) and 4) the durations of the tracer cloud (Td) behaved non-linearly as function of length scale. For example, plots of arrivals of leading edges and tailing edges with scale distance appear to define curves of the form; Tl=27.665e1.07× Distance (r2=0.99) and Tt=162.62e0.8551× Distance (r2=0.99), respectively. The greatest non-linearity occurred for the time of tailing and the least for the time of leading edge. These observations are consistent with what would be expected with greater density of dams and/or storage volumes as the reach length increased upgradient. To come to a first approximation, we are currently modeling the breakthrough curves with the solute transport code OTIS to address the relative differences in average travel velocity, longitudinal dispersion, and storage parameters from the mouth to the headwaters of the creek.
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Kopitz, Jürgen; Vértesy, Sabine; André, Sabine; Fiedler, Sabine; Schnölzer, Martina; Gabius, Hans-Joachim
2014-09-01
Many human proteins have a modular design with receptor and structural domains. Using adhesion/growth-regulatory galectin-3 as model, we describe an interdisciplinary strategy to define the functional significance of its tail established by nine non-triple helical collagen-like repeats (I-IX) and the N-terminal peptide. Genetic engineering with sophisticated mass spectrometric product analysis provided the tools for biotesting, i.e. eight protein variants with different degrees of tail truncation. Evidently,various aspects of galectin-3 activity (cis binding and cell bridging) are affected by tail shortening in a different manner. Thus, this combined approach reveals an unsuspected complexity of structure-function relationship, encouraging further application beyond this chimera-type galectin. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
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Kamiya, Seitaro; Hagimori, Masayori; Ogasawara, Masayoshi; Arakawa, Masayuki
2010-01-01
Thrombosis is characterized by congenital and acquired procatarxis. Nattokinase inhibits thrombus formation in vitro. However, in vivo evaluation of the therapeutic efficacy of nattokinase against thrombosis remains to be conducted. Subcutaneous nattokinase injections of 1 or 2 mg/ml were administered to the tails of rats. Subsequently, κ-carrageenan was intravenously administered to the tails at 12 h after nattokinase injections. The mean length of the infarcted regions in the tails of rats was significantly shorter in rats administered 2 mg/ml of nattokinase than those in control rats. Nattokinase exhibited significant prophylactic antithrombotic effects. Previously, the in vitro efficacy of nattokinase against thrombosis had been reported; now our study has revealed the in vivo efficacy of nattokinase against thrombosis. Copyright © 2010 S. Karger AG, Basel.
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Non-Gaussian Nature of Fracture and the Survival of Fat-Tail Exponents
NASA Astrophysics Data System (ADS)
Tallakstad, Ken Tore; Toussaint, Renaud; Santucci, Stephane; Måløy, Knut Jørgen
2013-04-01
We study the fluctuations of the global velocity Vl(t), computed at various length scales l, during the intermittent mode-I propagation of a crack front. The statistics converge to a non-Gaussian distribution, with an asymmetric shape and a fat tail. This breakdown of the central limit theorem (CLT) is due to the diverging variance of the underlying local crack front velocity distribution, displaying a power law tail. Indeed, by the application of a generalized CLT, the full shape of our experimental velocity distribution at large scale is shown to follow the stable Levy distribution, which preserves the power law tail exponent under upscaling. This study aims to demonstrate in general for crackling noise systems how one can infer the complete scale dependence of the activity—and extreme event distributions—by measuring only at a global scale.
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van Wyk, Jan A; Mayhew, Estelle
2013-03-13
In 2004, a new concept was introduced for simplifying identification of larvae of the common nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L3) of each genus and/or species to that of Trichostrongylus spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean length of the sheath tail extension (the extension of the sheath caudad, beyond the caudal tip of the larva) of Trichostrongylus colubriformis and Trichostrongylus axei is assumed to be 'X', then that of Haemonchus contortus is 2.0-2.7 'X' - a difference that is not difficult to estimate. An additional new approach suggested now, particularly for L3 of species and/or genera difficult to differentiate (such as Chabertia ovina and Oesophagostomum columbianum), is to estimate the proportion of the larval sheath tail extension comprising a terminal thin, whip-like filament. For the experienced person, it is seldom necessary to measure more than one or two sheath tail extensions of L3 in a mixed culture, because the identity of most of the remaining L3 can thereafter be estimated in relation to those measured, without having to take further measurements. The aim of this article was to present the novel approach in the form of a working guide for routine use in the laboratory. To facilitate identification, figures and a separate organogram for each of small ruminants and cattle have been added to illustrate the distinguishing features of the common L3.
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Asl, Ebrahim Zahedi; Niknam, Gholamreza; Jabbari, Habibeh; Pena-Santiago, Reyes
2016-08-10
Two new Nygolaimoides species are described and illustrated from soil and stumps of an old nursery of Populus alba, Miandoab County, West Azarbaijan province, Iran. Nygolaimoides zarrinensis sp. n. is characterized by its 0.73-0.94 mm long body, lip region 9.5-10.5 µm broad, odontostyle 9.5-11.0 µm long, neck length 162-194 µm long, pharyngeal expansion 78-83 µm long, V = 46-50, female tail short and rounded conoid (11-15 µm, c = 63-84, c' = 0.7-0.9), male tail rounded conoid (14-18 µm, c = 43-55, c' = 0.9-1.1), spicules 21-25 µm long and with irregular head, and two ventromedian supplements bearing hiatus. Nygolaimoides albus sp. n. is distinguished by its 0.64-0.95 mm long body, lip region 8-10 µm broad, odontostyle 9.5-11.0 µm long, neck length 164-200 µm long, pharyngeal expansion 66-72 µm long, V = 43-51, female tail hemispheroid (4.0-5.5 µm, c = 120-233, c' = 0.4-0.7), male tail conoid (9.0-12.0 µm, c = 58-78, c' = 0.7-1.0), spicules 13-17 µm long, and two ventromedian supplements bearing hiatus. SEM observations have been made for the first time for representatives of this genus. The taxonomy of the genus is updated with a list of its species, a key to their identification and a table-compendium of relevant morphometrics.
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Observations at venus encounter by the plasma science experiment on mariner 10.
Bridge, H S; Lazarus, A J; Scudder, J D; Ogilvie, K W; Hartle, R E; Asbridge, J R; Bame, S J; Feldman, W C; Siscoe, G L
1974-03-29
Preliminary results from the rearward-looking electrostatic analyzer of the plasma science experiment during the Mariner 10 encounter with Venus are described. They show that the solar-wind interaction with the planet probably involves a bow shock rather than an extended exosphere, but that this is not a thin boundary at the point where it was crossed by Mariner 10. An observed reduction in the flux of electrons with energies greater than 100 electron volts is interpreted as evidence for somne direct interaction with the exosphere. Unusual intermittent features observed downstream of the planet indicate the presence of a comet-like tail hundreds of scale lengths in length.
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Observations at Venus encounter by the plasma science experiment on Mariner 10
NASA Technical Reports Server (NTRS)
Bridge, H. S.; Lazarus, A. J.; Scudder, J. D.; Ogilvie, K. W.; Hartle, R. E.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Siscoe, G. L.
1974-01-01
Preliminary results from the rearward-looking electrostatic analyzer of the plasma science experiment during the Mariner 10 encounter with Venus are described. They show that the solar-wind interaction with the planet probably involves a bow shock rather than an extended exosphere, but that this is not a thin boundary at the point where it was crossed by Mariner 10. An observed reduction in the flux of electrons with energies greater than 100 electron volts is interpreted as evidence for some direct interaction with the exosphere. Unusual intermittent features observed downstream of the planet indicate the presence of a comet-like tail hundreds of scale lengths in length.
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Optimization of power generating thermoelectric modules utilizing LNG cold energy
NASA Astrophysics Data System (ADS)
Jeong, Eun Soo
2017-12-01
A theoretical investigation to optimize thermoelectric modules, which convert LNG cold energy into electrical power, is performed using a novel one-dimensional analytic model. In the model the optimum thermoelement length and external load resistance, which maximize the energy conversion ratio, are determined by the heat supplied to the cold heat reservoir, the hot and cold side temperatures, the thermal and electrical contact resistances and the properties of thermoelectric materials. The effects of the thermal and electrical contact resistances and the heat supplied to the cold heat reservoir on the maximum energy conversion ratio, the optimum thermoelement length and the optimum external load resistance are shown.
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New Cyst Nematode, Heterodera sojae n. sp. (Nematoda: Heteroderidae) from Soybean in Korea.
Kang, Heonil; Eun, Geun; Ha, Jihye; Kim, Yongchul; Park, Namsook; Kim, Donggeun; Choi, Insoo
2016-12-01
A new soybean cyst nematode Heterodera sojae n. sp. was found from the roots of soybean plants in Korea. Cysts of H. sojae n. sp. appeared more round, shining, and darker than that of H. glycines . Morphologically, H. sojae n. sp. differed from H. glycines by fenestra length (23.5-54.2 µm vs. 30-70 µm), vulval silt length (9.0-24.4 µm vs. 43-60 µm), tail length of J2 (54.3-74.8 µm vs. 40-61 µm), and hyaline part of J2 (32.6-46.3 µm vs. 20-30 µm). It is distinguished from H. elachista by larger cyst (513.4-778.3 µm × 343.4-567.1 µm vs. 350-560 µm × 250-450 µm) and longer stylet length of J2 (23.8-25.3 µm vs. 17-19 µm). Molecular analysis of rRNA large subunit (LSU) D2-D3 segments and ITS gene sequence shows that H. sojae n. sp. is more close to rice cyst nematode H. elachista than H. glycines . Heterodera sojae n. sp. was widely distributed in Korea. It was found from soybean fields of all three provinces sampled.
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Fayyaz, Shahina; Khanum, Tabassum Ara; Ali, Shaukat; Solangi, Ghulam Sarwar; Gulsher, Mehreen; Javed, Salma
2015-01-07
A new species of entomopathogenic nematode (EPN) named Steinernema balochiense n. sp. belonging to the family Steinernematidae was isolated from Psidium guajava L., rhizophere soil samples of Balochistan, Pakistan. This new species belongs to the carpocapsae group. The new species can be separated from other described species by morphological and morphometrics characteristics as well as DNA sequence polymorphisms. This new nematode species is morphologically characterized by features of infective juveniles (IJ) and males. For the IJ average body length was (455; 415-528) µm, distance from anterior end to excretory pore (35; 32-38) µm, pharynx length (90; 85-98) µm, tail length (44.3; 40-51) µm, D% and E% values (39; 36-44) and (80; 70-92), respectively. For male specimens, the diagnostic characters included total body length (1330; 1135-1632) µm, gubernaculum length (44.4; 40-47) µm, D% (43.8; 40-51) and ratio of GS (63.8; 53-75). Morphological diagnostic traits for new species include the presence of a funnel shaped gubernaculum at the proximal end. S. balochiense n. sp. differs from infective stage juveniles of closest species S. nepalense by having 6 ridges vs 7 ridges in the lateral field. Molecular phylogenetic trees based on sequence of ITS-rDNA, D2D3 regions and the mitochondrial 12S rRNA gene supports the description of this nematode isolate as a new species.
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Calmodulin overexpression does not alter Cav1.2 function or oligomerization state.
Findeisen, Felix; Tolia, Alexandra; Arant, Ryan; Kim, Eun Young; Isacoff, Ehud; Minor, Daniel L
2011-01-01
Interactions between calmodulin (CaM) and voltage-gated calcium channels (Ca(v)s) are crucial for Ca(v) activity-dependent feedback modulation. We recently reported an X-ray structure that shows two Ca(2+)/CaM molecules bound to the Ca(v)1.2 C terminal tail, one at the PreIQ region and one at the IQ domain. Surprisingly, the asymmetric unit of the crystal showed a dimer in which Ca(2+)/CaM bridged two PreIQ helixes to form a 4:2 Ca(2+)/CaM:Ca(v) C-terminal tail assembly. Contrary to previous proposals based on a similar crystallographic dimer, extensive biochemical analysis together with subunit counting experiments of full-length channels in live cell membranes failed to find evidence for multimers that would be compatible with the 4:2 crossbridged complex. Here, we examine this possibility further. We find that CaM over-expression has no functional effect on Ca(v)1.2 inactivation or on the stoichiometry of full-length Ca(v)1.2. These data provide further support for the monomeric Ca(v)1.2 stoichiometry. Analysis of the electrostatic surfaces of the 2:1 Ca(2+)/CaM:Ca(V) C-terminal tail assembly reveals notable patches of electronegativity. These could influence various forms of channel modulation by interacting with positively charged elements from other intracellular channel domains.
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Human Myo19 is a novel myosin that associates with mitochondria
Quintero, Omar A.; DiVito, Melinda M.; Adikes, Rebecca C.; Kortan, Melisa B.; Case, Lindsay B.; Lier, Audun J.; Panaretos, Niki S.; Slater, Stephanie Q.; Rengarajan, Michelle; Feliu, Marianela; Cheney, Richard E.
2009-01-01
Summary Mitochondria are pleomorphic organelles [1, 2] that have central roles in cell physiology. Defects in their localization and dynamics lead to human disease [3-5]. Myosins are actin-based motors that power processes such as muscle contraction, cytokinesis, and organelle transport [6]. Here we report the initial characterization of myosin-XIX (Myo19), the founding member of a novel class of myosin that associates with mitochondria. The 970aa heavy chain consists of a motor domain, three IQ motifs, and a short tail. Myo19 mRNA is expressed in multiple tissues and antibodies to human Myo19 detect a ∼109kD band in multiple cell lines. Both endogenous Myo19 and GFP-Myo19 exhibit striking localization to mitochondria. Deletion analysis reveals that the Myo19 tail is necessary and sufficient for mitochondrial localization. Expressing full-length GFP-Myo19 in A549 cells reveals a remarkable gain-of-function where the majority of the mitochondria move continuously. Moving mitochondria travel for many microns with an obvious leading end and distorted shape. The motility and shape-change are sensitive to latrunculin B, indicating that both are actin-dependent. Expressing the GFP-Myo19 tail in CAD cells resulted in decreased mitochondrial run lengths in neurites. These results suggest that this novel myosin functions as an actin-based motor for mitochondrial movement in vertebrate cells. PMID:19932026
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Carbajal-López, Yolanda; Gómez-Arroyo, Sandra; Villalobos-Pietrini, Rafael; Calderón-Segura, María Elena; Martínez-Arroyo, Amparo
2016-02-01
The aim of this study was to evaluate the genotoxic effect of pesticides in exfoliated buccal cells of workers occupationally exposed in Guerrero, Mexico, using the comet assay and the micronucleus test. The study compared 111 agricultural workers in three rural communities (Arcelia 62, Ajuchitlan 13, and Tlapehuala 36), with 60 non-exposed individuals. All the participants were males. The presence of DNA damage was investigated in the exfoliated buccal cells of study participants with the comet assay and the micronucleus (MN) test; comet tail length was evaluated in 100 nuclei and 3000 epithelial cells of each individual, respectively; other nuclear anomalies such as nuclear buds, karyolysis, karyorrhexis, and binucleate cells were also evaluated. Study results revealed that the tail migration of DNA and the frequency of MN increased significantly in the exposed group, which also showed nuclear anomalies associated with cytotoxic or genotoxic effect. No positive correlation was noted between exposure time and tail length and micronuclei frequencies. No significant effect on genetic damage was observed as a result of age, smoking, and alcohol consumption. The MN and comet assay in exfoliated buccal cells are useful and minimally invasive methods for monitoring genetic damage in individuals exposed to pesticides. This study provided valuable data for establishing the possible risk to human health associated with pesticide exposure.
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Ditchkoff, S.S.; Lochmiller, R.L.; Masters, R.E.; Starry, W.R.; Leslie, David M.
2001-01-01
Secondary sexual characters have been hypothesized to signal male quality and should demonstrate a negative relationship between the size of the trait and degree of fluctuating asymmetry because they are costly to produce. We collected morphometric and antler data from 439 white-tailed deer (Odocoileus virginianus) in Oklahoma, USA, in order to determine whether measures of antler asymmetry follow the patterns predicted for sexually selected characters. Relative fluctuating asymmetry was negatively related to antler size for all deer and within age groups up to five and a half years of age. We did not detect an association between asymmetry and antler size among deer that were six and a half years or older. When categorizing deer by antler size, we found that deer with small antlers (???33rd percentile) had greater levels of relative asymmetry than deer with large antlers (???67th percentile). The relative asymmetry of antlers was negatively related to age and was greatest in deer that were one and a half years old. Relative asymmetry was also negatively related to carcass mass, inside spread, skull length and body length. These data suggest that asymmetry in the antlers of white-tailed deer may be a reliable signal of quality and, as such, may be important in maintaining honesty in intrasexual advertisements during the breeding season.
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The comet moment as a measure of DNA damage in the comet assay.
Kent, C R; Eady, J J; Ross, G M; Steel, G G
1995-06-01
The development of rapid assays of radiation-induced DNA damage requires the definition of reliable parameters for the evaluation of dose-response relationships to compare with cellular endpoints. We have used the single-cell gel electrophoresis (SCGE) or 'comet' assay to measure DNA damage in individual cells after irradiation. Both the alkaline and neutral protocols were used. In both cases, DNA was stained with ethidium bromide and viewed using a fluorescence microscope at 516-560 nm. Images of comets were stored as 512 x 512 pixel images using OPTIMAS, an image analysis software package. Using this software we tested various parameters for measuring DNA damage. We have developed a method of analysis that rigorously conforms to the mathematical definition of the moment of inertia of a plane figure. This parameter does not require the identification of separate head and tail regions, but rather calculates a moment of the whole comet image. We have termed this parameter 'comet moment'. This method is simple to calculate and can be performed using most image analysis software packages that support macro facilities. In experiments on CHO-K1 cells, tail length was found to increase linearly with dose, but plateaued at higher doses. Comet moment also increased linearly with dose, but over a larger dose range than tail length and had no tendency to plateau.
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The tails of the satellite auroral footprints at Jupiter
NASA Astrophysics Data System (ADS)
Bonfond, B.; Saur, J.; Grodent, D.; Badman, S. V.; Bisikalo, D.; Shematovich, V.; Gérard, J.-C.; Radioti, A.
2017-08-01
The electromagnetic interaction between Io, Europa, and Ganymede and the rotating plasma that surrounds Jupiter has a signature in the aurora of the planet. This signature, called the satellite footprint, takes the form of a series of spots located slightly downstream of the feet of the field lines passing through the moon under consideration. In the case of Io, these spots are also followed by an extended tail in the downstream direction relative to the plasma flow encountering the moon. A few examples of a tail for the Europa footprint have also been reported in the northern hemisphere. Here we present a simplified Alfvénic model for footprint tails and simulations of vertical brightness profiles for various electron distributions, which favor such a model over quasi-static models. We also report here additional cases of Europa footprint tails, in both hemispheres, even though such detections are rare and difficult. Furthermore, we show that the Ganymede footprint can also be followed by a similar tail. Finally, we present a case of a 320° long Io footprint tail, while other cases in similar configurations do not display such a length.
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Effect of fuel volatility on performance of tail-pipe burner
NASA Technical Reports Server (NTRS)
Barson, Zelmar; Sargent, Arthur F , Jr
1951-01-01
Fuels having Reid vapor pressures of 6.3 and 1.0 pounds per square inch were investigated in a tail-pipe burner on an axial-flow-type turbojet engine at a simulated flight Mach number of 0.6 and altitudes from 20,000 to 45,000 feet. With the burner configuration used in this investigation, having a mixing length of only 8 inches between the fuel manifold and the flame holder, the low-vapor-pressure fuel gave lower combustion efficiency at a given tail-pipe fuel-air ratio. Because the exhaust-nozzle area was fixed, the lower efficiency resulted in lower thrust and higher specific fuel consumption. The maximum altitude at which the burner would operate was practically unaffected by the change in fuel volatility.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Dong, C. F.; Zhao, T. Z.; Behm, K.
Here, bright and ultrashort duration x-ray pulses can be produced by through betatron oscillations of electrons during laser wakefield acceleration (LWFA). Our experimental measurements using the Hercules laser system demonstrate a dramatic increase in x-ray flux for interaction distances beyond the depletion/dephasing lengths, where the initial electron bunch injected into the first wake bucket catches up with the laser pulse front and the laser pulse depletes. A transition from an LWFA regime to a beam-driven plasma wakefield acceleration regime consequently occurs. The drive electron bunch is susceptible to the electron-hose instability and rapidly develops large amplitude oscillations in its tail,more » which leads to greatly enhanced x-ray radiation emission. We measure the x-ray flux as a function of acceleration length using a variable length gas cell. 3D particle-in-cell simulations using a Monte Carlo synchrotron x-ray emission algorithm elucidate the time-dependent variations in the radiation emission processes.« less
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Martins, M L; Yoshitoshi, E R; Umekita, H
2001-05-01
The present work studied helminth parasites of "pacu-manteiga", Myleus tiete (Osteichthyes: Characidae) from Volta Grande Reservoir, MG, Brazil. Fishes with 142.6 +/- 24.7 g weight and 17.3 +/- 1.0 cm total length were collected. Five out six analysed fish (prevalence 83.3%) were parasitized in the intestine with an average of 535.6 +/- 334.6 oxyurid nematodes per fish. The helminth was identified as Ichthyouris voltagrandensis n.sp. (Nematoda: Pharyngodonidae). It differs from I. brasiliensis (Moravec et al., 1992a) by the absence of lateral alae, higher measures of tail and caudal alae of males, esophageal isthmus length, distance of excretory pore from anterior end and spicule length. In addition, eggs were provided by two long filaments in just one pole and by the first time the authors observed flagellate spermatozoa from dissected males. The authors exposes comparative table of measures of the five described species of the genus Ichthyouris.
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NASA Astrophysics Data System (ADS)
Dong, C. F.; Zhao, T. Z.; Behm, K.; Cummings, P. G.; Nees, J.; Maksimchuk, A.; Yanovsky, V.; Krushelnick, K.; Thomas, A. G. R.
2018-04-01
Bright and ultrashort duration x-ray pulses can be produced by through betatron oscillations of electrons during laser wakefield acceleration (LWFA). Our experimental measurements using the Hercules laser system demonstrate a dramatic increase in x-ray flux for interaction distances beyond the depletion/dephasing lengths, where the initial electron bunch injected into the first wake bucket catches up with the laser pulse front and the laser pulse depletes. A transition from an LWFA regime to a beam-driven plasma wakefield acceleration regime consequently occurs. The drive electron bunch is susceptible to the electron-hose instability and rapidly develops large amplitude oscillations in its tail, which leads to greatly enhanced x-ray radiation emission. We measure the x-ray flux as a function of acceleration length using a variable length gas cell. 3D particle-in-cell simulations using a Monte Carlo synchrotron x-ray emission algorithm elucidate the time-dependent variations in the radiation emission processes.
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Dong, C. F.; Zhao, T. Z.; Behm, K.; ...
2018-04-24
Here, bright and ultrashort duration x-ray pulses can be produced by through betatron oscillations of electrons during laser wakefield acceleration (LWFA). Our experimental measurements using the Hercules laser system demonstrate a dramatic increase in x-ray flux for interaction distances beyond the depletion/dephasing lengths, where the initial electron bunch injected into the first wake bucket catches up with the laser pulse front and the laser pulse depletes. A transition from an LWFA regime to a beam-driven plasma wakefield acceleration regime consequently occurs. The drive electron bunch is susceptible to the electron-hose instability and rapidly develops large amplitude oscillations in its tail,more » which leads to greatly enhanced x-ray radiation emission. We measure the x-ray flux as a function of acceleration length using a variable length gas cell. 3D particle-in-cell simulations using a Monte Carlo synchrotron x-ray emission algorithm elucidate the time-dependent variations in the radiation emission processes.« less
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NASA Astrophysics Data System (ADS)
Katiyatiya, C. L. F.; Muchenje, V.; Mushunje, A.
2015-06-01
Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals ( P < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms ( P < 0.05). High tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale ( P < 0.05). White and brown-white patched cows had significantly longer ( P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower ( P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different ( P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.
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1944-07-12
of tall area tlaes tall length are nearly the same. The airplane eas stable, « tick fixed, In all condi- tions except vave-off *lth the center of...in all conditions •icept aeve.off. A table of neutral points, both stick free end « tick flaed. for the XSBA-1 airplane «1th tall -it.figuration...I follostai Condition Ct Keutral point, Neutral point. • tick fixed •tlek free illding Cruising Cllablnc Landing approach •eve.off C.« 1.0
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77 FR 52265 - Airworthiness Directives; Eurocopter Deutschland GmbH Helicopters
Federal Register 2010, 2011, 2012, 2013, 2014
2012-08-29
... total area of corrosion or thread damage, or both, covers less than 25 percent of the length of the... paragraph (d)(3) of this AD. (B) If the total area of corrosion or thread damage, or both, covers 25 percent... to require inspections for corrosion or thread damage to each tail rotor balance weight (weight) and...
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Large Fluctuations for Spatial Diffusion of Cold Atoms
NASA Astrophysics Data System (ADS)
Aghion, Erez; Kessler, David A.; Barkai, Eli
2017-06-01
We use a new approach to study the large fluctuations of a heavy-tailed system, where the standard large-deviations principle does not apply. Large-deviations theory deals with tails of probability distributions and the rare events of random processes, for example, spreading packets of particles. Mathematically, it concerns the exponential falloff of the density of thin-tailed systems. Here we investigate the spatial density Pt(x ) of laser-cooled atoms, where at intermediate length scales the shape is fat tailed. We focus on the rare events beyond this range, which dominate important statistical properties of the system. Through a novel friction mechanism induced by the laser fields, the density is explored with the recently proposed non-normalized infinite-covariant density approach. The small and large fluctuations give rise to a bifractal nature of the spreading packet. We derive general relations which extend our theory to a class of systems with multifractal moments.
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NASA Astrophysics Data System (ADS)
Tucker, G. E.; Bradley, D. N.
2008-12-01
Many geomorphic transport laws assume that the transport process is local, meaning that the space and time scales of particle displacement are short relative to those of the system as a whole. This assumption allows one to express sediment flux in terms of at-a-point properties such as the local surface gradient. However, while this assumption is quite reasonable for some processes (for example, grain displacement by raindrop impact), it is questionable for others (such as landsliding). Moreover, particle displacement distance may also depend on slope angle, becoming longer as gradient increases. For example, the average motion distance during sediment ravel events on very steep slopes may approach the length of the entire hillslope. In such cases, the mass flux through a given point may depend not only on the local topography but also on topography some distance upslope, thus violating the locality assumption. Here we use a stochastic, particle- based model of hillslope evolution to gain insight into the potential for, and consequences of, nonlocality in sediment transport. The model is designed as a simple analogy for a host of different processes that displace sediment grains on hillslopes. The hillslope is represented as a two-dimensional pile of particles. These particles undergo quasi-random motion according to the following rules: (1) during each iteration, a particle and a direction are selected at random; (2) the particle hops in the direction of motion with a probability that depends on the its height relative to that of its immediate neighbor; (3) the particle continues making hops in the same direction and with the same probability dependence, until coming to rest or exiting the base of the slope. The topography and motion statistics that emerge from these rules show a range of behavior that depends on a dimensionless relief parameter. At low relief, hillslope shape is parabolic, mean displacement length is on the order of two particle widths, and the probability distribution of displacement length is thin- tailed (approximately exponential). At high relief, hillslopes become planar, average displacement length increases by an order of magnitude, and the displacement-length distribution becomes heavy-tailed (albeit truncated at the slope length). Across the spectrum of relief values, the relationship between mean flux and gradient resembles the family of nonlinear flux-gradient curves that has been used to model hillslope evolution. We compare the emergent morphology and transport statistics with linear, nonlinear, and fractional diffusion models of hillslope transport.
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NASA Technical Reports Server (NTRS)
Allen, Jerry M.
2005-01-01
An experimental study has been performed to develop a large force and moment aerodynamic data set on a slender axisymmetric missile configuration having cruciform strakes and in-line control tail fins. The data include six-component balance measurements of the configuration aerodynamics and three-component measurements on all four tail fins. The test variables include angle of attack, roll angle, Mach number, model buildup, strake length, nose size, and tail fin deflection angles to provide pitch, yaw, and roll control. Test Mach numbers ranged from 0.60 to 4.63. The entire data set is presented on a CD-ROM that is attached to this paper. The CD-ROM also includes extensive plots of both the six-component configuration data and the three-component tail fin data. Selected samples of these plots are presented in this paper to illustrate the features of the data and to investigate the effects of the test variables.
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NASA Technical Reports Server (NTRS)
Allen, Jerry M.
2005-01-01
An experimental study has been performed to develop a large force and moment aerodynamic data set on a slender axisymmetric missile configuration having cruciform strakes and in-line control tail fins. The data include six-component balance measurements of the configuration aerodynamics and three-component measurements on all four tail fins. The test variables include angle of attack, roll angle, Mach number, model buildup, strake length, nose size, and tail fin deflection angles to provide pitch, yaw, and roll control. Test Mach numbers ranged from 0.60 to 4.63. The entire data set is presented on a CD-ROM that is attached to this paper. The CD-ROM also includes extensive plots of both the six-component configuration data and the three-component tail fin data. Selected samples of these plots are presented in this paper to illustrate the features of the data and to investigate the effects of the test variables.
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Nucleotide sequence of Hungarian grapevine chrome mosaic nepovirus RNA1.
Le Gall, O; Candresse, T; Brault, V; Dunez, J
1989-01-01
The nucleotide sequence of the RNA1 of hungarian grapevine chrome mosaic virus, a nepovirus very closely related to tomato black ring virus, has been determined from cDNA clones. It is 7212 nucleotides in length excluding the 3' terminal poly(A) tail and contains a large open reading frame extending from nucleotides 216 to 6971. The presumably encoded polyprotein is 2252 amino acids in length with a molecular weight of 250 kDa. The primary structure of the polyprotein was compared with that of other viral polyproteins, revealing the same general genetic organization as that of other picorna-like viruses (comoviruses, potyviruses and picornaviruses), except that an additional protein is suspected to occupy the N-terminus of the polyprotein. PMID:2798128
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NASA Technical Reports Server (NTRS)
Ralston, J.
1983-01-01
The influence of airplane components, as well as wing location and tail length, on the rotational flow aerodynamics is discussed for a 1/6 scale general aviation airplane model. The airplane was tested in a built-up fashion (i.e., body, body-wing, body-wing-vertical, etc.) in the presence of two wing locations and two body lengths. Data were measured, using a rotary balance, over an angle-of-attack range of 8 deg to 90 deg, and for clockwise and counter-clockwise rotations covering an omega b/2V range of 0 to 0.9.
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Initial stages of aggregation in aqueous solutions of ionic liquids: molecular dynamics studies.
Bhargava, B L; Klein, Michael L
2009-07-16
Structures formed by 1-alkyl-3-methylimidazolium bromide aqueous solutions with decyl, dodecyl, tetradecyl, and hexadecyl chains have been studied using molecular dynamics (MD) simulations. Spontaneous self-assembly of the amphiphilic cations to form quasi-spherical polydisperse aggregates has been observed in all of the systems, with the size and nature of the aggregates varying with chain length. In all systems, the cation alkyl tails are buried deep inside the aggregates with the polar imidazolium group exposed to exploit the favorable interactions with water. Aggregation numbers steadily increase with the chain length. The hexadecyl aggregates have the most ordered internal structure of the systems studied, and the alkyl chains in these cations show the least number of gauche defects.
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Clausius, Ella; McMahon, Clive R; Hindell, Mark A
2017-01-01
The population of Southern elephant seals (Mirounga leonina) at Macquarie Island has declined since the 1960s, and is thought to be due to changing oceanic conditions leading to reductions in the foraging success of Macquarie Island breeding females. To test this hypothesis, we used a 55-year-old data set on weaning size of southern elephant seals to quantify a decrease in weaning size from a period of population stability in 1950s to its present state of on-going decline. Being capital breeders, the size of elephant seal pups at weaning is a direct consequence of maternal foraging success in the preceding year. During the 1940-1950s, the mean of female pups at weaning was similar between the Heard and Macquarie Island populations, while the snout-tail-length length of male weaners from Heard Island were longer than their conspecifics at Macquarie Island. Additionally, the snout-tail-length of pups at weaning decreased by 3cm between the 1950s and 1990s in the Macquarie Island population, concurrent with the observed population decline. Given the importance of weaning size in determining first-year survival and recruitment rates, the decline in the size at weaning suggests that the decline in the Macquarie Island population has, to some extent, been driven by reduced maternal foraging success, consequent declines in the size of pups at weaning, leading to reduced first-year survival rates and recruitment of breeding females into the population 3 to 4 years later.
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Miranda, L A; Affanni, J M; Paz, D A
2000-04-01
The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000. Copyright 2000 Wiley-Liss, Inc.
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Nematode cysts and larvae found in Achatina fulica Bowdich, 1822.
Franco-Acuña, D O; Pinheiro, J; Torres, E J L; Lanfredi, R M; Brandolini, S V P B
2009-02-01
This study describes the morphology of the nematode cysts and larvae found in Achatina fulica (giant African snail) in Brazil. Sixty snails were collected in Mesquita, Rio de Janeiro State. Fourteen of the snails were naturally infected. The cysts were spherical, pink colored and measured 0.97 to 1.57 mm in diameter. In the majority of cases they had a single larvae involved in amorphous material. A total of 222 encysted larvae were recovered. Of these, 30 were utilized in the morphological study. The length of the larvae varied from 2.57 to 5.8 mm and they were classified as small--up to 3.5 mm; medium--from 3.53 to 4.5 mm; and large--greater than 4.52 mm. The average length of the larvae in the three groups was 2.85, 3.87 and 5.23 mm, respectively. The larval cuticle was white, shiny and transversally striated until the posterior end of the body. At the anterior end there is a mouth with three lips, with amphids and papillae, followed by a muscular esophagus with average length of 0.61 mm, terminating in an esophageal bulb and having a nerve ring in the middle third of the esophagus, and an intestine with an opening near the posterior end. The tail begins from this opening and has two types of ends: short and abrupt or long and gradually tapering. The difference in the tail end can suggest sexual dimorphism, although no primordial reproductive structures were observed. These characteristics were not sufficient to identify the larvae, so there is a need for further study.
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Kim, Ji Young; Park, Ju Yeon; Kang, Hee Jung; Kim, Oh Yoen; Lee, Jong Ho
2012-07-17
The reported health benefits of Korean red ginseng (KRG) include antioxidant, antitumor, antimutagenic, and immunomodulatory activities; however, the effects on oxidative stress have not yet been evaluated. Therefore, we assessed the effect of KRG on antioxidant enzymes and oxidative stress markers in humans. We conducted a randomized, double-blind, placebo-controlled study with three groups, including placebo, low-dose (3 g/day), and high-dose (6 g/day), which were randomly assigned to healthy subjects aged 20-65 years. Lymphocyte DNA damage, antioxidative enzyme activity, and lipid peroxidation were assessed before and after the 8-week supplementation. Fifty-seven subjects completed the protocol. Plasma superoxide dismutase (SOD) activity after the 8-week KRG supplementation was significantly higher in the low-and high-dose groups compared to baseline. Plasma glutathione peroxidase (GPx) and catalase activities were also increased after the high-dose supplementation. Furthermore, the DNA tail length and tail moment were significantly reduced after the supplementation (low-dose and high-dose), and plasma oxidized low-density lipoprotein (LDL) levels were reduced in low-dose and high-dose groups, but increased in the placebo group. The net changes in oxidized LDL after the supplementation differed significantly between both KRG supplementation groups and the placebo group. Net changes in GPx, SOD and catalase activities, and DNA tail length and tail moment were significantly different between the high-dose group and the placebo group. Additionally, the net changes in urinary 8-epi-PGF(2α) were significantly different between the KRG supplementation groups and the placebo group. KRG supplementation may attenuate lymphocyte DNA damage and LDL oxidation by upregulating antioxidant enzyme activity.
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2012-01-01
Background The reported health benefits of Korean red ginseng (KRG) include antioxidant, antitumor, antimutagenic, and immunomodulatory activities; however, the effects on oxidative stress have not yet been evaluated. Therefore, we assessed the effect of KRG on antioxidant enzymes and oxidative stress markers in humans. Methods We conducted a randomized, double-blind, placebo-controlled study with three groups, including placebo, low-dose (3 g/day), and high-dose (6 g/day), which were randomly assigned to healthy subjects aged 20–65 years. Lymphocyte DNA damage, antioxidative enzyme activity, and lipid peroxidation were assessed before and after the 8-week supplementation. Results Fifty-seven subjects completed the protocol. Plasma superoxide dismutase (SOD) activity after the 8-week KRG supplementation was significantly higher in the low-and high-dose groups compared to baseline. Plasma glutathione peroxidase (GPx) and catalase activities were also increased after the high-dose supplementation. Furthermore, the DNA tail length and tail moment were significantly reduced after the supplementation (low-dose and high-dose), and plasma oxidized low-density lipoprotein (LDL) levels were reduced in low-dose and high-dose groups, but increased in the placebo group. The net changes in oxidized LDL after the supplementation differed significantly between both KRG supplementation groups and the placebo group. Net changes in GPx, SOD and catalase activities, and DNA tail length and tail moment were significantly different between the high-dose group and the placebo group. Additionally, the net changes in urinary 8-epi-PGF2α were significantly different between the KRG supplementation groups and the placebo group. Conclusions KRG supplementation may attenuate lymphocyte DNA damage and LDL oxidation by upregulating antioxidant enzyme activity. PMID:22805313
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Molecular mechanisms responsible for hydrate anti-agglomerant performance.
Phan, Anh; Bui, Tai; Acosta, Erick; Krishnamurthy, Pushkala; Striolo, Alberto
2016-09-28
Steered and equilibrium molecular dynamics simulations were employed to study the coalescence of a sI hydrate particle and a water droplet within a hydrocarbon mixture. The size of both the hydrate particle and the water droplet is comparable to that of the aqueous core in reverse micelles. The simulations were repeated in the presence of various quaternary ammonium chloride surfactants. We investigated the effects due to different groups on the quaternary head group (e.g. methyl vs. butyl groups), as well as different hydrophobic tail lengths (e.g. n-hexadecyl vs. n-dodecyl tails) on the surfactants' ability to prevent coalescence. Visual inspection of sequences of simulation snapshots indicates that when the water droplet is not covered by surfactants it is more likely to approach the hydrate particle, penetrate the protective surfactant film, reach the hydrate surface, and coalesce with the hydrate than when surfactants are present on both surfaces. Force-distance profiles obtained from steered molecular dynamics simulations and free energy profiles obtained from umbrella sampling suggest that surfactants with butyl tripods on the quaternary head group and hydrophobic tails with size similar to the solvent molecules can act as effective anti-agglomerants. These results qualitatively agree with macroscopic experimental observations. The simulation results provide additional insights, which could be useful in flow assurance applications: the butyl tripod provides adhesion between surfactants and hydrates; when the length of the surfactant tail is compatible with that of the hydrocarbon in the liquid phase a protective film can form on the hydrate; however, once a molecularly thin chain of water molecules forms through the anti-agglomerant film, connecting the water droplet and the hydrate, water flows to the hydrate and coalescence is inevitable.
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Swimming Back and Forth Using Planar Flagellar Propulsion at Low Reynolds Numbers.
Khalil, Islam S M; Tabak, Ahmet Fatih; Hamed, Youssef; Mitwally, Mohamed E; Tawakol, Mohamed; Klingner, Anke; Sitti, Metin
2018-02-01
Peritrichously flagellated Escherichia coli swim back and forth by wrapping their flagella together in a helical bundle. However, other monotrichous bacteria cannot swim back and forth with a single flagellum and planar wave propagation. Quantifying this observation, a magnetically driven soft two-tailed microrobot capable of reversing its swimming direction without making a U-turn trajectory or actively modifying the direction of wave propagation is designed and developed. The microrobot contains magnetic microparticles within the polymer matrix of its head and consists of two collinear, unequal, and opposite ultrathin tails. It is driven and steered using a uniform magnetic field along the direction of motion with a sinusoidally varying orthogonal component. Distinct reversal frequencies that enable selective and independent excitation of the first or the second tail of the microrobot based on their tail length ratio are found. While the first tail provides a propulsive force below one of the reversal frequencies, the second is almost passive, and the net propulsive force achieves flagellated motion along one direction. On the other hand, the second tail achieves flagellated propulsion along the opposite direction above the reversal frequency.
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Hafner, Anne-Sophie; Penn, Andrew C; Grillo-Bosch, Dolors; Retailleau, Natacha; Poujol, Christel; Philippat, Amandine; Coussen, Françoise; Sainlos, Matthieu; Opazo, Patricio; Choquet, Daniel
2015-04-22
PSD-95 is a prominent organizer of the postsynaptic density (PSD) that can present a filamentous orientation perpendicular to the plasma membrane. Interactions between PSD-95 and transmembrane proteins might be particularly sensitive to this orientation, as "long" cytoplasmic tails might be required to reach deeper PSD-95 domains. Extension/retraction of transmembrane protein C-tails offer a new way of regulating binding to PSD-95. Using stargazin as a model, we found that enhancing the apparent length of stargazin C-tail through phosphorylation or by an artificial linker was sufficient to potentiate binding to PSD-95, AMPAR anchoring, and synaptic transmission. A linear extension of stargazin C-tail facilitates binding to PSD-95 by preferentially engaging interaction with the farthest located PDZ domains regarding to the plasma membrane, which present a greater affinity for the stargazin PDZ-domain-binding motif. Our study reveals that the concerted orientation of the stargazin C-tail and PSD-95 is a major determinant of synaptic strength. Copyright © 2015 Elsevier Inc. All rights reserved.
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Comparative analysis of genetic architectures for nine developmental traits of rye.
Masojć, Piotr; Milczarski, P; Kruszona, P
2017-08-01
Genetic architectures of plant height, stem thickness, spike length, awn length, heading date, thousand-kernel weight, kernel length, leaf area and chlorophyll content were aligned on the DArT-based high-density map of the 541 × Ot1-3 RILs population of rye using the genes interaction assorting by divergent selection (GIABDS) method. Complex sets of QTL for particular traits contained 1-5 loci of the epistatic D class and 10-28 loci of the hypostatic, mostly R and E classes controlling traits variation through D-E or D-R types of two-loci interactions. QTL were distributed on each of the seven rye chromosomes in unique positions or as a coinciding loci for 2-8 traits. Detection of considerable numbers of the reversed (D', E' and R') classes of QTL might be attributed to the transgression effects observed for most of the studied traits. First examples of E* and F QTL classes, defined in the model, are reported for awn length, leaf area, thousand-kernel weight and kernel length. The results of this study extend experimental data to 11 quantitative traits (together with pre-harvest sprouting and alpha-amylase activity) for which genetic architectures fit the model of mechanism underlying alleles distribution within tails of bi-parental populations. They are also a valuable starting point for map-based search of genes underlying detected QTL and for planning advanced marker-assisted multi-trait breeding strategies.
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Energetic particles in the jovian magnetotail.
McNutt, R L; Haggerty, D K; Hill, M E; Krimigis, S M; Livi, S; Ho, G C; Gurnee, R S; Mauk, B H; Mitchell, D G; Roelof, E C; McComas, D J; Bagenal, F; Elliott, H A; Brown, L E; Kusterer, M; Vandegriff, J; Stern, S A; Weaver, H A; Spencer, J R; Moore, J M
2007-10-12
When the solar wind hits Jupiter's magnetic field, it creates a long magnetotail trailing behind the planet that channels material out of the Jupiter system. The New Horizons spacecraft traversed the length of the jovian magnetotail to >2500 jovian radii (RJ; 1 RJ identical with 71,400 kilometers), observing a high-temperature, multispecies population of energetic particles. Velocity dispersions, anisotropies, and compositional variation seen in the deep-tail (greater, similar 500 RJ) with a approximately 3-day periodicity are similar to variations seen closer to Jupiter in Galileo data. The signatures suggest plasma streaming away from the planet and injection sites in the near-tail region (approximately 200 to 400 RJ) that could be related to magnetic reconnection events. The tail structure remains coherent at least until it reaches the magnetosheath at 1655 RJ.
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Morphology of the caudal spinal cord in Rana (Ranidae) and Xenopus (Pipidae) tadpoles.
Nishikawa, K; Wassersug, R
1988-03-08
Using a variety of neuroanatomical and histological techniques, we compare the spinal cord and peripheral nerve distribution in the tails of larvae from Xenopus laevis and three species of Rana. The relatively large, postsacral spinal cord of Xenopus contains abundant motoneurons and their axons. Spinal nerves exit from the spinal cord in a regular array, one nerve per myotome, from the cervical region to near the end of the tail. Somata of motoneurons innervating caudal myotomes are found along the entire length of the tail. In contrast, the caudal cord of Rana is reduced to a filum terminale consisting of little more than an ependymal tube; spinal nerves to all caudal myotomes leave the cord in the sacral region and reach their motor targets via a cauda equina and caudal plexus. Motoneuron cell bodies innervating caudal myotomes are found only in the sacral region. The Rana larval pattern is similar to that of adult frogs and mammals, whereas the Xenopus larval pattern is more like that of salamanders and reptiles. These gross neuroanatomical differences are not due to differences in the size or developmental stage of the tadpoles, but instead are associated with differences in the swimming behavior of the larvae. The presence of motoneurons in the caudal spinal cord of Xenopus may provide local intermyotomal control within the tail; the elongated topography of the cord appears to permit finer, rostral-to-caudal regulation of neuromuscular activity. The Rana spinal cord, on the other hand--with motoneurons clustered anteriorly--may produce concurrent firing of adjacent ipsilateral myotomes, but at the expense of fine intermyotomal regulation. The fact that nerves in the tail of Xenopus enter and exit from the spinal cord locally, as opposed to far anteriorly as in Rana, means that for tadpoles of the same size, reflex arc lengths are many times shorter in Xenopus.
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Does cortical bone thickness in the last sacral vertebra differ among tail types in primates?
Nishimura, Abigail C; Russo, Gabrielle A
2017-04-01
The external morphology of the sacrum is demonstrably informative regarding tail type (i.e., tail presence/absence, length, and prehensility) in living and extinct primates. However, little research has focused on the relationship between tail type and internal sacral morphology, a potentially important source of functional information when fossil sacra are incomplete. Here, we determine if cortical bone cross-sectional thickness of the last sacral vertebral body differs among tail types in extant primates and can be used to reconstruct tail types in extinct primates. Cortical bone cross-sectional thickness in the last sacral vertebral body was measured from high-resolution CT scans belonging to 20 extant primate species (N = 72) assigned to tail type categories ("tailless," "nonprehensile short-tailed," "nonprehensile long-tailed," and "prehensile-tailed"). The extant dataset was then used to reconstruct the tail types for four extinct primate species. Tailless primates had significantly thinner cortical bone than tail-bearing primates. Nonprehensile short-tailed primates had significantly thinner cortical bone than nonprehensile long-tailed primates. Cortical bone cross-sectional thickness did not distinguish between prehensile-tailed and nonprehensile long-tailed taxa. Results are strongly influenced by phylogeny. Corroborating previous studies, Epipliopithecus vindobonensis was reconstructed as tailless, Archaeolemur edwardsi as long-tailed, Megaladapis grandidieri as nonprehensile short-tailed, and Palaeopropithecus kelyus as nonprehensile short-tailed or tailless. Results indicate that, in the context of phylogenetic clade, measures of cortical bone cross-sectional thickness can be used to allocate extinct primate species to tail type categories. © 2017 Wiley Periodicals, Inc.
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New Cyst Nematode, Heterodera sojae n. sp. (Nematoda: Heteroderidae) from Soybean in Korea
Kang, Heonil; Eun, Geun; Ha, Jihye; Kim, Yongchul; Park, Namsook; Kim, Donggeun; Choi, Insoo
2016-01-01
A new soybean cyst nematode Heterodera sojae n. sp. was found from the roots of soybean plants in Korea. Cysts of H. sojae n. sp. appeared more round, shining, and darker than that of H. glycines. Morphologically, H. sojae n. sp. differed from H. glycines by fenestra length (23.5–54.2 µm vs. 30–70 µm), vulval silt length (9.0–24.4 µm vs. 43–60 µm), tail length of J2 (54.3–74.8 µm vs. 40–61 µm), and hyaline part of J2 (32.6–46.3 µm vs. 20–30 µm). It is distinguished from H. elachista by larger cyst (513.4–778.3 µm × 343.4–567.1 µm vs. 350–560 µm × 250–450 µm) and longer stylet length of J2 (23.8–25.3 µm vs. 17–19 µm). Molecular analysis of rRNA large subunit (LSU) D2–D3 segments and ITS gene sequence shows that H. sojae n. sp. is more close to rice cyst nematode H. elachista than H. glycines. Heterodera sojae n. sp. was widely distributed in Korea. It was found from soybean fields of all three provinces sampled. PMID:28154434
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Mizutani, Yuichi; Niizuma, Yasuaki; Yoda, Ken
2016-01-01
Telomeres are nucleotide sequences located at the ends of chromosomes that promote genome stability. Changes in telomere length (dynamics) are related to fitness or life expectancy, and telomere dynamics during the development phase are likely to be affected by growth and stress factors. Here, we examined telomere dynamics of black-tailed gull chicks (Larus crassirostris) in nests with and without siblings. We found that the initial telomere lengths of singletons at hatching were longer than those of siblings, indicating that singletons are higher-quality chicks than siblings in terms of telomere length. Other factors likely affecting individual quality (i.e., sex, laying date, laying order of eggs, and clutch size) were not related to telomere lengths. Within broods, initial telomere lengths were longer in older chicks than in younger chicks, suggesting that maternal effects, which vary with laying sequence, influence the initial lengths. Additionally, telomeres of chicks with a sibling showed more attrition between hatching and fledging than those of singleton chicks, suggesting that being raised with siblings can cause a sustained competitive environment that leads to telomere loss. High growth rates were associated with a low degree of telomere shortening observed in older siblings, perhaps because slower growth reflects higher food stress and/or higher aerobic metabolism from increased begging effort. Our results show that developmental telomere attrition was an inevitable consequence in two-chick nests in the pre- and post-hatching microenvironments due to the combination of social stress within the nest and maternal effects. The results of our study shed light on telomere dynamics in early life, which may represent an important physiological undercurrent of life-history traits. PMID:27902754
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Effect of boattail geometry on the acoustics of parallel baffles in ducts
NASA Technical Reports Server (NTRS)
Soderman, P. T.; Unnever, G.; Dudley, M. R.
1984-01-01
Sound attenuation and total pressure drop of parallel duct baffles incorporating certain boattail geometries were measured in the NASA Ames Research Center 7- by 10-Foot Wind Tunnel. The baseline baffles were 1.56 m long and 20 cm thick, on 45-cm center-to-center spacings, and spanned the test section from floor to ceiling. Four different boattails were evaluated: a short, smooth (nonacoustic) boattail; a longer, smooth boattail; and two boattails with perforated surfaces and sound-absorbent filler. Acoustic measurements showed the acoustic boattails improved the sound attenuation of the baffles at approximately half the rate to be expected from constant-thickness sections of the same length; that is, 1.5 dB/n, where n is the ratio of acoustic treatment length to duct passage width between baffles. The aerodynamic total pressure loss was somewhat sensitive to tail geometry. Lengthening the tails to reduce the diffusion half-angle from 11 to 5 degrees reduced the total pressure loss approximately 9%. Perforating the boattails, which increased the surface roughness, did not have a large effect on the total pressure loss. Aerodynamic results are compared with a published empirical method for predicting baffle total pressure drop.
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Does weather shape rodents? Climate related changes in morphology of two heteromyid species
NASA Astrophysics Data System (ADS)
Wolf, Mosheh; Friggens, Michael; Salazar-Bravo, Jorge
2009-01-01
Geographical variation in morphometric characters in heteromyid rodents has often correlated with climate gradients. Here, we used the long-term database of rodents trapped in the Sevilleta National Wildlife Refuge in New Mexico, USA to test whether significant annual changes in external morphometric characters are observed in a region with large variations in temperature and precipitation. We looked at the relationships between multiple temperature and precipitation variables and a number of morphological traits (body mass, body, tail, hind leg, and ear length) for two heteromyid rodents, Dipodomys merriami and Perognathus flavescens. Because these rodents can live multiple years in the wild, the climate variables for the year of the capture and the previous 2 years were included in the analyses. Using multiple linear regressions, we found that all of our morphometric traits, with the exception of tail length in D. merriami, had a significant relationship with one or more of the climate variables used. Our results demonstrate that effects of climate change on morphological traits occur over short periods, even in noninsular mammal populations. It is unclear, though, whether these changes are the result of morphological plasticity or natural selection.
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NASA Astrophysics Data System (ADS)
White, Nicole A. S.; Ellis, Henry A.
2008-10-01
The molecular structures of a homologous series of lithium n-alkanoates have been determined at room temperature using infrared spectroscopy, polarizing light microscopy and X-ray powder diffraction in conjunction with density and melting point measurements. For all the compounds investigated, asymmetric ionic metal-carboxylate coordination is proposed, with the molecules located within a triclinic crystal system with P1¯ space group. The molecules are nearly all of similar structure and are arranged within lamellar layers with four molecules per unit cell. The hydrocarbon chains, in nearly all trans conformation, are arranged tail-to-tail and tilted at an average angle of 55 ο to the planes containing lithium ions. The unit cell parameters such as sides: b and c increase linearly with increasing chain length whilst side a shows a linear decrease. Furthermore, the measured densities and melting points show odd-even behaviour, suggesting differences in molecular packing between odd and even chain length homologues. Geometric models are proposed to explain molecular orientation within a lamella and odd-even behaviour, involving the influence of terminal groups on the packing geometry of hydrocarbon chains within the lattice.
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Wu, W J; Yan, L; Xu, C L; Yu, L; Wang, K; Jin, S Y; Xie, H
2016-07-01
One new species of the family Nordiidae Jairajpuri & Siddiqi, 1964 from the enclosure grassland of Qinghai Province, China, Heterodorus qinghaiensis n. sp., is described and illustrated. The new species is characterized by the slender body, 1.29-1.46 mm in length; the granular lateral chord with numerous large depression plaques throughout its entirety; the lip region offset by a distinct depression; amphid goblet-shaped with aperture about half to two-thirds of corresponding body diameter; odontostyle 11-13 μm long; rod-like odontophore without basal flanges; pharyngeal basal expansion about one-third of the total neck length; didelphic genital system containing sperm; ovaries generally not reaching the sphincter level; vulva transversed and sclerotized; female tail conoid with round terminus; 3-5 spaced ventromedial supplements and spicule 32-41 μm long. It is close to H. liangi (Ahmad, Wu & Shaheen, 2002) Andrássy, 2009, H. brevidentatus (Thorne, 1939) Andrássy, 2009, H. monticola Andrássy, 2011, H. morgensis (Loof, 1988) Andrássy, 2009 and H. meghalayensis (Mushtaq, Baniyamuddin & Ahmad, 2007) Andrássy, 2009 in having inconspicuous or no lateral body pores, smaller odontostyle and ventrally curved tail.
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Cimen, Harun; Půža, Vladimír; NermuŤ, JiŘí; Hatting, Justin; Ramakuwela, Tshima; Hazir, Selcuk
2016-01-01
A new species of entomopathogenic nematode (EPN), Steinernema biddulphi n. sp., was isolated from a maize field in Senekal, Free State Province of South Africa. Morphological and molecular studies indicated the distinctness of S. biddulphi n. sp. from other Steinernema species. Steinernema biddulphi n. sp. is characterized IJs with average body length of 663 μm (606–778 μm), lateral fields with six ridges in mid-body region forming the formula 2,6,2. Excretory pore located anterior to mid-pharynx (D% = 46). Hyaline layer occupies approximately half of tail length. Male spicules slightly to moderately curved, with a sharp tip and golden brown in color. The first generation of males lacking a mucron on the tail tip while the second generation males with a short filamentous mucron. Genital papillae with 11 pairs and one unpaired preanal papilla. The new species is further characterized by sequences of the internal transcribed spacer (ITS) and partial 28S regions (D2-D3) of the ribosomal DNA (rDNA). Phylogenetic data show that S. biddulphi n. sp. belongs to the “bicornutum” clade within the Steinernematidae family. PMID:27765988
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Garaj-Vrhovac, Vera; Orescanin, Visnja; Ruk, Damir; Gajski, Goran
2009-02-15
In vitro genotoxic effects of leachates of electric arc furnace dust (EAFD) on human peripheral lymphocytes, assessed prior and following the treatment with a strong alkaline solution were investigated using the alkaline comet assay. Prior and following the treatment, lymphocytes were incubated with leachate of EAFD for 6 and 24 hours at 37 degrees C. Negative controls were also included. Mean values of the tail lengths established in the samples treated with the leachate stemming from the original dust for 6 and 24 hours, were 15.70 microm and 16.78 microm, respectively, as compared to 12.33 microm found in the control sample. Slight, but significant increase in the tail length was also found with the dust treated with a strong alkaline solution (13.37 microm and 13.60 microm). In case of high heavy metal concentrations (the extract of the original furnace dust), the incubation period was revealed to be of significance as well. The obtained results lead to the conclusion that alkaline comet assay could be used as a rapid, sensitive and low-cost tool when assessing genotoxicity of various waste materials, such as leachates of the electric arc furnace dust.
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Márquez-Miranda, Valeria; Araya-Durán, Ingrid; Camarada, María Belén; Comer, Jeffrey; Valencia-Gallegos, Jesús A.; González-Nilo, Fernando Danilo
2016-01-01
An ideal nucleic-acid transfection system should combine the physical and chemical characteristics of cationic lipids and linear polymers to decrease cytotoxicity and uptake limitations. Previous research described new types of carriers termed amphiphilic dendrimers (ADs), which are based on polyamidoamine dendrimers (PAMAM). These ADs display the cell membrane affinity advantage of lipids and preserve the high affinity for DNA possessed by cationic dendrimers. These lipid/dendrimer hybrids consist of a low-generation, hydrophilic dendron (G2, G1, or G0) bonded to a hydrophobic tail. The G2-18C AD was reported to be an efficient siRNA vector with significant gene silencing. However, shorter tail ADs (G2-15C and G2-13C) and lower generation (G0 and G1) dendrimers failed as transfection carriers. To date, the self-assembly phenomenon of this class of amphiphilic dendrimers has not been molecularly explored using molecular simulation methods. To gain insight into these systems, the present study used coarse-grained molecular dynamics simulations to describe how ADs are able to self-assemble into an aggregate, and, specifically, how tail length and generation play a key role in this event. Finally, explanations are given for the better efficiency of G2/18-C as gene carrier in terms of binding of siRNA. This knowledge could be relevant for the design of novel, safer ADs with well-optimized affinity for siRNA. PMID:27377641
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Yabsley, Michael J.; Clay, Sarah E.; Gibbs, Samantha E. J.; Cunningham, Mark W.; Austel, Michaela G.
2013-01-01
Demodex mites, although usually nonpathogenic, can cause a wide range of dermatological lesions ranging from mild skin irritation and alopecia to severe furunculosis. Recently, a case of demodicosis from a white-tailed deer (Odocoileus virginianus) revealed a Demodex species morphologically distinct from Demodex odocoilei. All life cycle stages were considerably larger than D. odocoilei and although similar in size to D. kutzeri and D. acutipes from European cervids, numerous morphometrics distinguished the four species. Adult males and females were 209.1 ± 13.1 and 225.5 ± 13.4 μm in length, respectively. Ova, larva, and nymphs measured 65.1 ± 4.1, 124.9 ± 11.6, and 205.1 ± 19.4 μm in length, respectively. For phylogenetic analyses, a portion of the 18S rRNA gene was amplified and sequenced from samples of the WTD Demodex sp., two Demodex samples from domestic dogs, and Demodex ursi from a black bear. Phylogenetic analyses indicated that the WTD Demodex was most similar to D. musculi from laboratory mice. A partial sequence from D. ursi was identical to the WTD Demodex sequence; however, these two species can be differentiated morphologically. This paper describes a second Demodex species from white-tailed deer and indicates that 18S rRNA is useful for phylogenetic analysis of most Demodex species, but two morphologically distinct species had identical partial sequences. Additional gene targets should be investigated for phylogenetic and parasite-host association studies. PMID:27335854
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Pedram, Majid; Pourjam, Ebrahim; Atighi, Mohammad Reza; Panahandeh, Yousef
2015-06-01
Heterodorus youbertghostai n. sp. is described and illustrated based on morphological, morphometric, and molecular data. The new species was found in two geographically distant points in northwestern Iran and is characterized by having angular lip region, separated from the rest body by a constriction, body length of 1,432.5 to 1,751.3 µm, odontostyle length of 24 to 28 µm, rod-like odontophore, 37.0 to 42.5 µm long, lacking flanges at base, double guiding ring at 14 to 16 µm distance from anterior end, pharyngeal bulb comprising 40% to 48% of pharynx, intestine usually containing green material, female reproductive system amphidelphic with less divided short uterus, specific structure of pars distalis vaginae, bluntly conical tail, dorsally convex and ventrally flat, with rounded tip and saccate bodies in ventral side. The new species comes more close to H. conicaudatus and H. irregularis by its morphology and morphometric characters. Compared to former, it has remarkable difference in vulva position and tail characters, and compared to the latter, it could be separated by shorter body, posteriorly located vulva, wider lip region, and longer tail. In phylogenetic analyses using partial sequences of 28S rDNA D2-D3, the new species formed a fully supported clade with several isolates of H. brevidentatus, prevalent in Iran. The other nordiid taxon, Enchodorus dolichurus, already reported from Iran, was also sequenced for the same genomic region and included in phylogenetic analyses.
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Longidorus iranicus n.sp. (Nematoda: Dorylaimida).
Sturhan, D; Barooti, S
1983-03-01
Longidorus iranicus n.sp. is described from the north-western part of Iran, where it was found in the rhizosphere of grape and other cultivated plants. Its main features are a 5-7 mm long and rather slender body, a narrow, rounded lip region which is almost continuous with neck contour, an odontostyle length around 110 μm, a short, bluntly conoid tail, the shape of the amphids, the position of the gland nuclei in the oesophageal bulb, the cuticle layering at the tail end and the absence of males. L. iranicus resembles L. goodeyi, L. caespiticola, L. taniwha, L. poessneckensis and, most closely, L. crassus. ac]19820617.
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NASA Astrophysics Data System (ADS)
Massip, Florian; Arndt, Peter F.
2013-04-01
Recently, an enrichment of identical matching sequences has been found in many eukaryotic genomes. Their length distribution exhibits a power law tail raising the question of what evolutionary mechanism or functional constraints would be able to shape this distribution. Here we introduce a simple and evolutionarily neutral model, which involves only point mutations and segmental duplications, and produces the same statistical features as observed for genomic data. Further, we extend a mathematical model for random stick breaking to analytically show that the exponent of the power law tail is -3 and universal as it does not depend on the microscopic details of the model.
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Meeuwig, M.H.; Bayer, J.M.; Reiche, R.A.
2006-01-01
The effectiveness of morphometric and meristic characteristics for taxonomic discrimination of Lampetra tridentata and L. richardsoni (Petromyzonidae) during embryological, prolarval, and early larval stages (i.e., age class 1) were examined. Mean chorion diameter increased with time from fertilization to hatch and was significantly greater for L. tridentata than for L. richardsoni at 1, 8, and 15 days postfertilization. Lampetra tridentata larvae had significantly more trunk myomeres than L. richardsoni; however, trunk myomere numbers were highly variable within species and deviated from previously published data. Multivariate examinations of prolarval and larval L. tridentata (7.2-11.0 mm; standard length) and L. richardsoni (6.6-10.8 mm) were conducted based on standard length and truss element lengths established from eight homologous landmarks. Principal components analysis indicated allometric relationships among the morphometric characteristics examined. Changes in body shape were indicated by groupings of morphometric characteristics associated with body regions (e.g., oral hood, branchial region, trunk region, and tail region). Discriminant function analysis using morphometric characteristics was successful in classifying a large proportion (>94.7%) of the lampreys sampled.
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Newcombe, Estella A; Ruff, Kiersten M; Sethi, Ashish; Ormsby, Angelique R; Ramdzan, Yasmin M; Fox, Archa; Purcell, Anthony W; Gooley, Paul R; Pappu, Rohit V; Hatters, Danny M
2018-05-11
Soluble huntingtin exon 1 (Httex1) with expanded polyglutamine (polyQ) engenders neurotoxicity in Huntington's disease. To uncover the physical basis of this toxicity, we performed structural studies of soluble Httex1 for wild-type and mutant polyQ lengths. Nuclear magnetic resonance experiments show evidence for conformational rigidity across the polyQ region. In contrast, hydrogen-deuterium exchange shows absence of backbone amide protection, suggesting negligible persistence of hydrogen bonds. The seemingly conflicting results are explained by all-atom simulations, which show that Httex1 adopts tadpole-like structures with a globular head encompassing the N-terminal amphipathic and polyQ regions and the tail encompassing the C-terminal proline-rich region. The surface area of the globular domain increases monotonically with polyQ length. This stimulates sharp increases in gain-of-function interactions in cells for expanded polyQ, and one of these interactions is with the stress-granule protein Fus. Our results highlight plausible connections between Httex1 structure and routes to neurotoxicity. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Borreguero, Jose M.; Pincus, Philip A.; Sumpter, Bobby G.
Structure–property relationships of ionic block copolymer (BCP) surfactant complexes are critical toward the progress of favorable engineering design of efficient charge-transport materials. In this paper, molecular dynamics simulations are used to understand the dynamics of charged-neutral BCP and surfactant complexes. The dynamics are examined for two different systems: charged-neutral double-hydrophilic and hydrophobic–hydrophilic block copolymers with oppositely charged surfactant moieties. The dynamics of the surfactant head, tails, and charges are studied for five different BCP volume fractions. We observe that the dynamics of the different species solely depend on the balance between electrostatic and entropic interactions between the charged species andmore » the neutral monomers. The favorable hydrophobic–hydrophobic interactions and the unfavorable hydrophobic–hydrophilic interactions determine the mobilities of the monomers. The dynamical properties of the charge species influence complex formation. Structural relaxations exhibit length-scale dependent behavior, with slower relaxation at the radius of gyration length-scale and faster relaxation at the segmental length-scale, consistent with previous results. The dynamical analysis correlates ion-exchange kinetics to the self-assembly behavior of the complexes.« less
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Surfactant mediated polyelectrolyte self-assembly
Goswami, Monojoy; Borreguero Calvo, Jose M.; Pincus, Phillip A.; ...
2015-11-25
Self-assembly and dynamics of polyelectrolyte (PE) surfactant complex (PES) is investigated using molecular dynamics simulations. The complexation is systematically studied for five different PE backbone charge densities. At a fixed surfactant concentration the PES complexation exhibits pearl-necklace to agglomerated double spherical structures with a PE chain decorating the surfactant micelles. The counterions do not condense on the complex, but are released in the medium with a random distribution. The relaxation dynamics for three different length scales, polymer chain, segmental and monomer, show distinct features of the charge and neutral species; the counterions are fastest followed by the PE chain andmore » surfactants. The surfactant heads and tails have the slowest relaxation due to their restricted movement inside the agglomerated structure. At the shortest length scale, all the charge and neutral species show similar relaxation dynamics confirming Rouse behavior at monomer length scales. Overall, the present study highlights the structure-property relationship for polymer-surfactant complexation. These results will help improve the understanding of PES complex and should aid in the design of better materials for future applications.« less
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Tan, Wanyu; Li, Yongmei; Tan, Kaixuan; Duan, Xianzhe; Liu, Dong; Liu, Zehua
2016-12-01
Radon diffusion and transport through different media is a complex process affected by many factors. In this study, the fractal theories and field covering experiments were used to study the fractal characteristics of particle size distribution (PSD) of six kinds of geotechnical materials (e.g., waste rock, sand, laterite, kaolin, mixture of sand and laterite, and mixture of waste rock and laterite) and their effects on radon diffusion. In addition, the radon diffusion coefficient and diffusion length were calculated. Moreover, new formulas for estimating diffusion coefficient and diffusion length functional of fractal dimension d of PSD were proposed. These results demonstrate the following points: (1) the fractal dimension d of the PSD can be used to characterize the property of soils and rocks in the studies of radon diffusion behavior; (2) the diffusion coefficient and diffusion length decrease with increasing fractal dimension of PSD; and (3) the effectiveness of final covers in reducing radon exhalation of uranium tailings impoundments can be evaluated on the basis of the fractal dimension of PSD of materials.
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Age and sex identification of Akohekohe
Simon, John C.; Pratt, T.K.; Berlin, Kim E.; Kowalsky, James R.
1998-01-01
We present methods to determine the age and sex of Akohekohe (Palmeria dolei), an endangered Hawaiian honeycreeper, developed on the basis of 45 museum specimens and 91 live birds captured on the island of Maui. Akohekohe retained all Juvenal primaries, some Juvenal secondaries, and some body feathers after the first prebasic molt; they attained full adult plumage after the second prebasic molt. Retention of brown Juvenal body feathers, especially on the head, distinguished most birds in the first basic plumage from adults, which have a full complement of distinctive, black lanceolate body feathers with white, gray, or orange tips. Male Akohekohe were heavier than females and had longer wing, tail, and tarsometatarsus lengths. We present a linear discriminant function to sex both adults and juveniles using lengths of their wing and tarsometatarsus.
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Polymeric assemblies for sensitive colorimetric assays
Charych, Deborah
2000-01-01
The presently claimed invention relates to polymeric assemblies which visibly change color in the presence of analyte. In particular, the presently claimed invention relates to liposomes comprising a plurality of lipid monomers, which comprises a polymerizable group, a hydrophilic head group and a hydrophobic tail group, and one or more ligands. Overall carbon chain length, and polymerizable group positioning on the monomer influence color change sensitivity to analyte concentrations.
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Dronen, Norman O; Al-Kassar, Nothiala R; Ali, Atheer H; Abdulhameed, Mohanad F; Abdullah, Basim H; Al-Mayah, Sabeeh H
2017-03-09
A total of 19 white-tailed lapwing, Vanellus leucurus, were collected from Huwazah Marsh, north-eastern Basrah Province, Iraq from February to March and in October, 2011 (collection site #1) and 60 V. leucurus were collected from Al-Hammar Marshes, Thi-Qar Province, southern Iraq from July to November, 2012 (collection site #2), and examined for cyclocoelids. Nineteen Uvitellina iraquensis Dronen, Ali & Al-Amura, 2013 from site #1 and 17 specimens from site #2 were fixed with minimal compression for comparisons of morphological characteristics, measurements, morphometric percentages and morphometric ratios commonly used to distinguish species of cyclocoelids. An additional five adult specimens from site #1 were fixed without compression for comparisons. Specimens from site # 1 (n=24) represented only fully-developed, non-senescing adults, while those from site #2 (n=17) could be divided into fully-developed (non-senescing) adults (n=8); younger (smaller, less developed) adults (n=5) and senescing adults (n=4). The following characteristics were relatively consistent, and appeared to be valuable in identifying groups of similar species and distinguishing species in Uvitellina: the presence or absence of the oral sucker; the oral sucker/pharynx width ratio; the posterior extent of the cirrus sac relative to the intestinal bifurcation; the position of the genital pore relative to the pharynx; the position of the testes in the body; the length of the intertesticular space; the length of the posttesticular space; the lateral disposition of the uterine loops; the presence of a posteriorly-directed, tail-like extension off the posterior confluence of the vitelline fields; the posterior extent of the uterine loops relative to the gonads; and the size of fully-developed eggs. It may be beneficial to calculate the percentage that measurements represent relative to the body length to provide insight into the relationship of the size of a structure to increased size of the specimens (growth). Specimens fixed without compression appeared to be less uniform, less symmetrical, shorter, more distorted and the internal details were more difficult to see.
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Triply Periodic Multiply Continuous Lyotropic Liquid Crystals Derived from Gemini Surfactants
NASA Astrophysics Data System (ADS)
Sorenson, Gregory P.
A subtle balance of non-covalent interactions directs the self-assembly of small molecule amphiphiles in aqueous media into supramolecular assemblies known as aqueous lyotropic liquid crystals (LLCs). Aqueous LLCs form many intricate, ordered nanoscale morphologies comprising distinct and structurally periodic hydrophobic and hydrophilic domains. Triply periodic multiply continuous (TPMC) LLC morphologies, which exhibit continuous hydrophobic and aqueous domains that percolate in three-dimensions, are of particular interest by virtue of their potentially wide ranging technological applications including advanced membranes for electrical energy storage and utilization, therapeutic delivery, and templates for new organic and inorganic mesoporous materials. However, robust molecular design criteria for amphiphiles that readily form TMPC morphologies are notably lacking in the literature. Recent reports have described the increased propensity for quaternary ammonium and phosphonium gemini surfactants, derived from dimerization of traditional single-tail surfactants at or near the hydrophilic headgroups through a hydrophobic linker, to stabilize TMPC mesophases. The generality of this surfactant design strategy remains untested in other amphiphiles classes bearing different headgroup chemistries. In this thesis, we describe the unusual aqueous LLC phase behavior of series of gemini dicarboxylate amphiphiles as a function of the alkyl tail length, hydrophobic linker length, and the charge-compensating counterion. These dicarboxylate surfactants unexpectedly exhibit a strong propensity to form TPMC LLCs over amphiphile concentration windows as wide as 20 wt% over a temperature range T = 25--100 °C. Through systematic modifications of the length of the hydrophobic linker and alkyl tails, we use small-angle X-ray scattering to demonstrate that these surfactants adopt new LLC mesophases including the first report of a single-gyroid phase (I4132 symmetry) and a new, tetracontinuous hexagonal network phase ( P63/mcm symmetry). Additionally, we probe the role of the linker position in the surfactant architecture. These data taken together indicate the sensitive dependence of the LLC phase behavior on counterion-headgroup correlations. Based on these molecular design criteria, we demonstrate the synthesis of a polymerizable gemini surfactant that may be self-assembled into a TPMC LLC phase and covalently fixed by a crosslinking photopolymerization. Comprised of aqueous nanochannels lined with metal carboxylates, the resulting LLC membranes exhibit high ionic conductivities.
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Ahad, Sumaya; Ahmad, Wasim
2016-11-09
This paper deals with the description of three new and one known species of the genus Proleptonchus Lordello, 1955. Proleptonchus kazirangus n. sp. from Kaziranga National Park, India is characterized by having 1.08-1.45 mm long body; cap-like, offset, lip region; 7-8 µm long odontostyle and 10-12 µm long odontophore; short, pear-shaped pharyngeal bulb offset by a constriction, occupying about 18-21% of total neck length; female genital system mono-prodelphic; pars dilatata uteri with distinctly sclerotized central lumen containing refringent apophyses; posterior uterine sac 78-112 µm long, with sac-like structure representing a rudimentary oviduct; transverse vulva, short, rounded-conoid tail and males with 31-33 µm long spicules, lateral guiding pieces and seven, regularly spaced ventromedian supplements. P. prerectus n. sp. from Japan is characterized by having 1.18-1.43 mm long body; lip region cap-like, offset by a slight constriction; odontostyle 8 µm, odontophore 9-10 µm; short cylindroid basal bulb offset by a constriction, occupying about 16-20% of total neck length; female genital system mono-prodelphic; pars dilatata uteri with sclerotized refringent apophyses; posterior uterine sac small, 27-36 µm; transverse vulva; a prerectal chamber and short, rounded-hemispheroid tail. P. japonicus n. sp. also from Japan is characterized by having 0.91-1.04 mm long body; lip region cap-like, set off by a slight constriction; odontostyle 5 µm and odontophore 10-11 µm long; pharynx consists of a very slender, non-muscular anterior part, separated from pyriform basal bulb by a constriction, with thickened lumen in posterior region, occupying about 18-20% of total neck length; female genital system mono-prodelphic; posterior uterine sac small, 20-24 µm long; transverse vulva and short, rounded-conoid tail. P. shamimi Bajaj & Bhatti, 1980 is redescribed and its relationship with closely related species is discussed. A diagnostic compendium of all the valid species of Proleptonchus is also provided.
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Baier, Fabian; Gruber, Edith; Hein, Thomas; Bondar-Kunze, Elisabeth; Ivanković, Marina; Mentler, Axel; Brühl, Carsten A; Spangl, Bernhard; Zaller, Johann G
2016-01-01
Glyphosate-based herbicides are the most widely used pesticides in agriculture, horticulture, municipalities and private gardens that can potentially contaminate nearby water bodies inhabited by amphibians and algae. Moreover, the development and diversity of these aquatic organisms could also be affected by human-induced climate change that might lead to more periods with extreme temperatures. However, to what extent non-target effects of these herbicides on amphibians or algae are altered by varying temperature is not well known. We studied effects of five concentrations of the glyphosate-based herbicide formulation Roundup PowerFlex (0, 1.5, 3, 4 mg acid equivalent glyphosate L -1 as a one time addition and a pulse treatment of totally 4 mg a.e. glyphosate L -1 ) on larval development of Common toads ( Bufo bufo , L.; Amphibia: Anura) and associated algae communities under two temperature regimes (15 vs. 20 °C). Herbicide contamination reduced tail growth (-8%), induced the occurrence of tail deformations (i.e. lacerated or crooked tails) and reduced algae diversity (-6%). Higher water temperature increased tadpole growth (tail and body length (tl/bl) +66%, length-to-width ratio +4%) and decreased algae diversity (-21%). No clear relation between herbicide concentrations and tadpole growth or algae density or diversity was observed. Interactive effects of herbicides and temperature affected growth parameters, tail deformation and tadpole mortality indicating that the herbicide effects are temperature-dependent. Remarkably, herbicide-temperature interactions resulted in deformed tails in 34% of all herbicide treated tadpoles at 15 °C whereas no tail deformations were observed for the herbicide-free control at 15 °C or any tadpole at 20 °C; herbicide-induced mortality was higher at 15 °C but lower at 20 °C. These herbicide- and temperature-induced changes may have decided effects on ecological interactions in freshwater ecosystems. Although no clear dose-response effect was seen, the presence of glyphosate was decisive for an effect, suggesting that the lowest observed effect concentration (LOEC) in our study was 1.5 mg a.e. glyphosate L -1 water. Overall, our findings also question the relevance of pesticide risk assessments conducted at standard temperatures.
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Baier, Fabian; Gruber, Edith; Bondar-Kunze, Elisabeth; Ivanković, Marina; Mentler, Axel; Brühl, Carsten A.; Spangl, Bernhard
2016-01-01
Background Glyphosate-based herbicides are the most widely used pesticides in agriculture, horticulture, municipalities and private gardens that can potentially contaminate nearby water bodies inhabited by amphibians and algae. Moreover, the development and diversity of these aquatic organisms could also be affected by human-induced climate change that might lead to more periods with extreme temperatures. However, to what extent non-target effects of these herbicides on amphibians or algae are altered by varying temperature is not well known. Methods We studied effects of five concentrations of the glyphosate-based herbicide formulation Roundup PowerFlex (0, 1.5, 3, 4 mg acid equivalent glyphosate L−1 as a one time addition and a pulse treatment of totally 4 mg a.e. glyphosate L−1) on larval development of Common toads (Bufo bufo, L.; Amphibia: Anura) and associated algae communities under two temperature regimes (15 vs. 20 °C). Results Herbicide contamination reduced tail growth (−8%), induced the occurrence of tail deformations (i.e. lacerated or crooked tails) and reduced algae diversity (−6%). Higher water temperature increased tadpole growth (tail and body length (tl/bl) +66%, length-to-width ratio +4%) and decreased algae diversity (−21%). No clear relation between herbicide concentrations and tadpole growth or algae density or diversity was observed. Interactive effects of herbicides and temperature affected growth parameters, tail deformation and tadpole mortality indicating that the herbicide effects are temperature-dependent. Remarkably, herbicide-temperature interactions resulted in deformed tails in 34% of all herbicide treated tadpoles at 15 °C whereas no tail deformations were observed for the herbicide-free control at 15 °C or any tadpole at 20 °C; herbicide-induced mortality was higher at 15 °C but lower at 20 °C. Discussion These herbicide- and temperature-induced changes may have decided effects on ecological interactions in freshwater ecosystems. Although no clear dose-response effect was seen, the presence of glyphosate was decisive for an effect, suggesting that the lowest observed effect concentration (LOEC) in our study was 1.5 mg a.e. glyphosate L−1 water. Overall, our findings also question the relevance of pesticide risk assessments conducted at standard temperatures. PMID:27833808
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Passerine morphology: external measurements of approximately one-quarter of passerine bird species.
Ricklefs, Robert E
2017-05-01
Studies of community organization and clade diversification that include functional traits have become an important component of the analysis of ecological and evolved systems. Such studies frequently are limited by availability of consistently collected data. Here, I present a data set including eight measurements of the external morphology of 1642 species, roughly one-quarter of all passerine birds (Aves: Order Passeriformes), from all parts of the world, characterizing the relative proportions of the wing, tail, legs, and beak. Specimens were measured opportunistically over the past 40 years in museums in the United States and Europe. Numbers of individuals measured per species vary from one to dozens in some cases. Measurements for males and females of sexually size-dimorphic species are presented separately. The measurements include total length, the lengths of the wing, tail, tarsus, and middle toe, and the length, breadth, and depth of the beak. Particular attention was paid to obtaining a broad representation of passerine higher taxa, with special interest in small families and subfamilies of passerines, as well as species produced by evolutionary radiations of birds in archipelagoes, including the Galapagos, Hawaii, and the Lesser Antilles. Taxonomy follows the Taxonomy in Flux (TIF) checklist as well as the World Bird List of the International Ornithological Council. Geographic distributions are summarized from Edwards's Coded List of Birds of the World. Coverage of taxa and geographic regions varies and reflects the changing interests of the author over the past four decades. North American and South American species are particularly well represented in the sample, as well as species belonging to the families Tyrannidae, Furnariidae, Thamnophilidae, Mimidae, Sturnidae, Fringillidae, Parulidae, Icteridae, Cardinalidae, and Thraupidae. © 2017 by the Ecological Society of America.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Stillman, A.E.; Wilke, N.; Li, D.
Our goal was to determine the feasibility of using an intravascular MR contrast agent to improve 3D MRA. Three-dimensional TOF MRA was performed in nine patients both prior to and following the administration of an ultrasmall particle superparamagnetic iron oxide contrast agent (AMI 227). The lengths of both renal arteries were measured from the maximum intensity projection (MIP) images as well as the individual partitions. Seven of these patients also were studied by a 3D coronary artery MRA sequence. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements of the right coronary artery were determined both prior to and following themore » administration of AMI 227. Statistical analysis of both renal artery lengths and right coronary SNR and CNR was performed using a one tailed paired t test comparing pre- and postcontrast images. The renal artery lengths significantly increased (right renal artery: 30%, p = 0.001; left renal artery: 25%, p < 0.008) when measured from the individual axial slice partitions. No significant increase in length was observed on the MIP images following contrast. In the right coronary artery, the SNR increased by an average of 80% (p = 0.008) and CNR increased by an average of 109% (p = 0.007). Increased background signal and superimposed venous structures reduced the measurable lengths of the renal arteries from the MIP images. These studies support the hypothesis that 3D MRA in the body will benefit from the use of intravascular contrast agents. Nevertheless, conventional MIP processing is unable to reveal the full advantage of the contrast improvement. 14 refs., 6 figs., 2 tabs.« less
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Qu, Yan-Fu; Lu, Hong-Liang; Li, Hong; Ji, Xiang
2014-12-01
Studies examining the effects of incubation temperature fluctuation on the phenotype of hatchling reptiles have shown species variation. To examine whether incubation temperature fluctuation has a key role in influencing the phenotype of hatchling Chinese skinks (Plestiodon chinensis), we incubated eggs produced by 20 females under five thermal regimes (treatments). Eggs in three treatments were incubated in three incubators, one set constant at 27°C and two ramp-programmed at 27 ± 3°C and 27 ± 5°C on a cycle of 12h (+) and 12h (-). The remaining eggs were incubated in two chambers: one inside a room where temperatures varied from 23.0 to 31.1°C, with a mean of 27.0°C; the other outside the room where temperatures varied from 20.2 to 35.3°C, with a mean of 26.1°C. We found that: (1) for eggs at a given embryonic stage at ovipositon, the mean rather than the variance of incubation temperatures determined the length of incubation; (2) most (egg mass, embryonic stage at oviposition, incubation length and all examined hatchling traits except tail length and locomotor performance) of the examined variables were affected by clutch; and (3) body mass was the only hatchling trait that differed among the five treatments, but the differences were tiny. These findings suggest that incubation temperature fluctuation has no direct role in influencing incubation length and hatchling phenotype in P. chinensis. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Junker, Kerstin; Mariaux, Jean; Measey, G John; Mutafchiev, Yasen
2015-10-01
Meteterakis saotomensis n. sp. is described from Schistometopum thomense (Bocage), a gymnophionan endemic to the oceanic island of São Tomé in the Gulf of Guinea. The specimens were assigned to Meteterakis Karve, 1930, based on the possession of a head with three rounded lips, not set-off from the body, the absence of interlabia and cordons, females with a long vagina and males with a preanal sucker, surrounded by a cuticularised rim and caudal alae that are supported by fleshy papillae. The new species is characterised by: body length 4.2-4.5 mm (males) and 5.1-6.4 mm (females); total length of oesophagus, including pharyngeal portion and oesophageal bulb, 820-856 µm (males) and 898-1,070 µm (females); length of pharynx 57-58 µm (males) and 65-68 µm (females); spicules equal, 410-521 µm long, with tessellated ornamentation throughout their length and alae, and with bevelled tip; gubernaculum or 'gubernacular mass' absent; tail length 164-176 µm (males) and 214-239 µm (females), with elongated tip; vulva at 2.3-2.8 mm from anterior end, with anterior lip forming small flap. This is the second species of Meteterakis reported from gymnophionan hosts and the first from the Afrotropical region. Selected comparative morphological data for Meteterakis spp. are presented, and data on host range and geographic distribution are updated. The name M. striaturus Oshmarin & Demshin, 1972 is corrected to M. striatura to reflect the female gender of the genus name.
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Trouble with diffusion: Reassessing hillslope erosion laws with a particle-based model
NASA Astrophysics Data System (ADS)
Tucker, Gregory E.; Bradley, D. Nathan
2010-03-01
Many geomorphic systems involve a broad distribution of grain motion length scales, ranging from a few particle diameters to the length of an entire hillslope or stream. Studies of analogous physical systems have revealed that such broad motion distributions can have a significant impact on macroscale dynamics and can violate the assumptions behind standard, local gradient flux laws. Here, a simple particle-based model of sediment transport on a hillslope is used to study the relationship between grain motion statistics and macroscopic landform evolution. Surface grains are dislodged by random disturbance events with probabilities and distances that depend on local microtopography. Despite its simplicity, the particle model reproduces a surprisingly broad range of slope forms, including asymmetric degrading scarps and cinder cone profiles. At low slope angles the dynamics are diffusion like, with a short-range, thin-tailed hop length distribution, a parabolic, convex upward equilibrium slope form, and a linear relationship between transport rate and gradient. As slope angle steepens, the characteristic grain motion length scale begins to approach the length of the slope, leading to planar equilibrium forms that show a strongly nonlinear correlation between transport rate and gradient. These high-probability, long-distance motions violate the locality assumption embedded in many common gradient-based geomorphic transport laws. The example of a degrading scarp illustrates the potential for grain motion dynamics to vary in space and time as topography evolves. This characteristic renders models based on independent, stationary statistics inapplicable. An accompanying analytical framework based on treating grain motion as a survival process is briefly outlined.
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Fiedler, Wolfgang
2005-06-01
An analysis of the external flight apparatus of 700 blackcaps from eight different populations (sedentary to long-distance migrators) is presented. With increasing migration distances of populations, (1) wing length, aspect ratio, and wing pointedness increase; (2) wing load decreases; (3) slots on the wing tips become relatively shorter; (4) the alula tends to be shorter in relation to wing length; and (5) the tail is shorter in relation to wing length. Although body mass increases from southern to northern populations, changes in wing length and wing area are two to three times larger than expected for simple isometric relationships. Regarding the aerodynamic background of these changes, it can be stated that traits for energy-effective flight are more strongly developed and traits for maneuverability are less developed in birds traveling longer distances, presumably as a consequence of trade-offs. Nonmigratory blackcaps from Madeira and the Cape Verde islands do not always show the traits we would expect in view of their sedentary behavior. This can be seen as a result of recent colonization of these islands by migrants or of selection by factors other than migration behavior. In migratory populations, changes between the first and the second set of primaries during first complete molt show almost the same pattern as the changes from nonmigratory to migratory populations. During molt of the primaries, blackcaps of nonmigratory populations do not show these changes. Hybrids between migrating and nonmigrating blackcap populations (Moscow and Madeira) showed intermediate values between parent populations in wing length, wing shape, and wing area; in the other variables they resembled either parent population.
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Hypersonic shock tunnel heat transfer tests of the Space Shuttle SILTS pod configuration
NASA Technical Reports Server (NTRS)
Wittliff, C. E.
1983-01-01
Heat transfer measurements have been made on a 0.0175-scale NASA Space Shuttle orbiter model having a simulated SILTS (Shuttle Infrared Leeside Temperature Sensor) pod on top of the vertical tail. Heat transfer distributions were measured both on the pod and on the vertical tail. The test program covered Mach numbers of 8, 11 and 16 in air, at Reynolds numbers from 100,000 to 18 million, based on model length. The angle of attack ranged from 30 deg to 40 deg at sideslip angles from -2 to +2 deg. Data were obtained with 92 thin film assistance thermometers located on the SILTS pod and on the upper 30 percent of the vertical tail. Heat transfer rates measured on the vertical tail show good agreement with flight data obtained from missions STS-1, -2 and -3. The variation of heat transfer to the pod with Reynolds number, Mach number and angle of attack is discussed.
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Milkovic, Durdica; Garaj-Vrhovac, Vera; Ranogajec-Komor, Mária; Miljanic, Saveta; Gajski, Goran; Knezevic, Zeljka; Beck, Natko
2009-01-01
The aim of this work is to assess DNA damage in peripheral blood lymphocytes of children prior to and following airway X-ray examinations of the chest using the alkaline comet assay and to compare data with the measured absorbed dose. Twenty children with pulmonary diseases, between the ages of 5 and 14 years, are assessed. Absorbed dose measurements are conducted for posterior-anterior projection on the forehead, thyroid gland, gonads, chest, and back. Doses are measured using thermoluminescent and radiophotoluminescent dosimetry systems. Differences between tail lengths, tail intensity, and tail moments as well as for the long-tailed nuclei before and after exposures are statistically significant and are dependent on the individual. The results demonstrate the usefulness of the comet assay as a measure of X-ray damage to lymphocytes in a clinical setting. Doses measured with both dosimeters show satisfactory agreement (0.01 mSv) and are suitable for dosimetric measurements in X-ray diagnostics.
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Ionic Liquids with Symmetric Diether Tails: Bulk and Vacuum-Liquid Interfacial Structures.
Hettige, Jeevapani J; Amith, Weththasinghage D; Castner, Edward W; Margulis, Claudio J
2017-01-12
The behavior in the bulk and at interfaces of biphilic ionic liquids in which either the cation or anion possesses moderately long alkyl tails is to a significant degree well understood. Less clear is what happens when both the cation and anion possess tails that are not apolar, such as in the case of ether functionalities. The current article discusses the structural characteristics of C2OC2OC2-mim + /C2OC2OC2-OSO 3 - in the bulk and at the vacuum interface. We find that the vacuum interface affects only the nanometer length scale. This is in contrast to what we have recently found in ( J. Phys. Chem. Lett. , 2016 , 7 ( 19 ), 3785 - -3790 ) for isoelectronic C[8]-mim + /C[8]-OSO 3 - , where the interface effect is long ranged. Interestingly, ions with the diether tail functionality still favor the tail-outward orientation at the vacuum interface and the bulk phase preserves the alternation between charged networks and tails that is commonly observed for biphilic ionic liquids. However, such alternation is less well-defined and results in a significantly diminished first sharp diffraction peak in the bulk liquid structure function.
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Disproportionate entrance length in superfluid flows and the puzzle of counterflow instabilities
NASA Astrophysics Data System (ADS)
Bertolaccini, J.; Lévêque, E.; Roche, P.-E.
2017-12-01
Systematic simulations of the two-fluid model of superfluid helium (He-II) encompassing the Hall-Vinen-Bekharevich-Khalatnikov (HVBK) mutual coupling have been performed in two-dimensional pipe counterflows between 1.3 and 1.96 K. The numerical scheme relies on the lattice Boltzmann method. A Boussinesq-like hypothesis is introduced to omit temperature variations along the pipe. In return, the thermomechanical forcings of the normal and superfuid components are fueled by a pressure term related to their mass-density variations under an approximation of weak compressibility. This modeling framework reproduces the essential features of a thermally driven counterflow. A generalized definition of the entrance length is introduced to suitably compare entry effects (of different nature) at opposite ends of the pipe. This definition is related to the excess of pressure loss with respect to the developed Poiseuille-flow solution. At the heated end of the pipe, it is found that the entrance length for the normal fluid follows a classical law and increases linearly with the Reynolds number. At the cooled end, the entrance length for the superfluid is enhanced as compared to the normal fluid by up to one order of magnitude. At this end, the normal fluid flows into the cooling bath of He-II and produces large-scale superfluid vortical motions in the bath that partly re-enter the pipe along its sidewalls before being damped by mutual friction. In the superfluid entry region, the resulting frictional coupling in the superfluid boundary layer distorts the velocity profiles toward tail flattening for the normal fluid and tail raising for the superfluid. Eventually, a simple analytical model of entry effects allows us to re-examine the long-debated thresholds of T 1 and T 2 instabilities in superfluid counterflows. Inconsistencies in the T 1 thresholds reported since the 1960s disappear if an aspect-ratio criterion based on our modeling is used to discard data sets with the strongest entry effects. Furthermore, it is observed that entry effects can spuriously reproduce the signature of a T 2 transition with a normal flow remaining laminar.
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Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard
NASA Astrophysics Data System (ADS)
Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros
2017-02-01
Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.
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Tail autotomy affects bipedalism but not sprint performance in a cursorial Mediterranean lizard.
Savvides, Pantelis; Stavrou, Maria; Pafilis, Panayiotis; Sfenthourakis, Spyros
2017-02-01
Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.
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A morphological database for 606 colombian bird species.
Montoya, Paola; Gonzalez, Mailyn A; Tenorio, Elkin A; López-Ordóñez, Juan Pablo; Pinto Gómez, Alejandro; Cueva, Diego; Acevedo Rincón, Aldemar A; Angarita Yanes, Camilo; Arango Martínez, Héctor Manuel; Armesto, Orlando; Betancur, Jefry S; Caguazango Castro, Angela; Calderon Leyton, Jhon Jairo; Calpa-Anaguano, Edna Viviana; Cárdenas-Posada, Ghislaine; Castaño Díaz, Michael; Chaparro-Herrera, Sergio; Diago-Muñoz, Nicolás; Franco Espinosa, Laura; Gómez Bernal, Luis Germán; Gonzalez-Zapata, Fanny L; Gutiérrez Zamora, Eduardo Aquiles; Gutiérrez-Zuluaga, Ana M; Lizcano Jiménez, Robinson Stivel; Lopera-Salazar, Andrea; Martínez Alvarado, Dariel; Maya Girón, Ana María; Medina, Wilderson; Montealegre-Talero, Carolina; Parra, Juan L; Pérez-Peña, Sebastián; Ramírez Ramírez, Francis; Reyes, Julián; Rivera-Gutiérrez, Héctor Fabio; Rosero Mora, Yuri; Trujillo-Torres, Carlos M; Vidal-Maldonado, Cristian Camilo; Salgado-Negret, Beatriz
2018-04-27
Colombia is the country with the highest bird diversity in the world. Despite active research in ornithology, compelling morphological information of most bird species is still sparse. However, morphological information is the baseline to understand how species respond to environmental variation and how ecosystems respond to species loss. As part of a national initiative, the Instituto Alexander von Humboldt in collaboration with twelve Colombian institutions and seven biological collections, measured up to 15 morphological traits of 9892 individuals corresponding to 606 species: 3492 from individuals captured in field and 6400 from museum specimens. Species measured are mainly distributed in high Andean forest, páramo, and wetland ecosystems. Overall, seven ornithological collections in Colombia and 18 páramo complexes throughout Colombia were visited from 2013 to 2015. The morphological traits involved measurements from bill (total and exposed culmen, bill width and depth), wing (length, area, wingspan and the distance between longest primary and longest secondary), tail (length and shape), tarsus (length), hallux (length and claw hallux) and weight. The number of measured specimens per species was variable, ranging from 1 to 321 individuals with a median of 4 individuals per species. Overall, this database gathered morphological information for more than 30% of Colombian bird diversity. No copyright, proprietary, or cost restrictions apply; the data should be cited appropriately when used. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
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Effect of central corneal thickness, corneal curvature, and axial length on applanation tonometry.
Kohlhaas, Markus; Boehm, Andreas G; Spoerl, Eberhard; Pürsten, Antje; Grein, Hans J; Pillunat, Lutz E
2006-04-01
To evaluate the effect of central corneal thickness (CCT), corneal curvature, and axial length on applanation tonometry in an in vivo study. In a masked, prospective clinical trial, we examined 125 eyes of 125 patients scheduled for cataract surgery. Corneal curvature was measured by means of keratometry and axial length by A-scan ultrasonography. By cannulating the anterior chamber before surgery, intraocular pressure (IOP) was set to 20, 35, and 50 mm Hg in a closed system by means of a water column. After measuring thickness, the IOP was measured with an applanation tonometer. Pearson product moment correlations and multiple linear regression analyses were performed, and significance levels were evaluated by the paired, 2-tailed t test. The difference between measured and real IOP was significantly dependent (P < .001) on CCT. The associations between IOP and corneal curvature or IOP and axial length were not statistically significant (P = .31). The association between IOP reading and CCT is shown in the "Dresdner correction table," which illustrates an approximately 1-mm Hg correction for every 25-microm deviation from a CCT of 550 microm. The correction values were positive as thickness decreased and negative as thickness increased. Central corneal thickness significantly affects IOP readings obtained by applanation tonometry according to the Goldmann principle. A correction of IOP readings by considering CCT according to the Dresdner correction table might be helpful for determining an accurate IOP value.
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Adult females and pubic bone growth.
Fuller, K
1998-07-01
Previous research (Tague [1994] Am. J. Phys. Anthropol. 95:27-40) has shown an age effect in pubic bone length among adult women. Tague found that in three prehistoric Native American skeletal samples, women aged 18-24 had a significantly shorter linea terminalis than did women aged 25 and older. The purpose of this research is to determine whether such a difference can be discerned in other female skeletal samples. Three female skeletal samples were used in this analysis: 75 African-American and 42 European-American females aged 18-39 from the Hamann-Todd Collection (collected between 1893 and 1938; Iscan, 1990) and 99 African-American females aged 18-39 from the Terry Collection (collected between 1914 and 1965; Cobb, 1933; Iscan, 1990). Several chord measurements of pubic bone length along the linea terminalis were analyzed by one-tailed t-tests of the separate samples subdivided into two age groups: 18-24 and 25-39 years. Of 15 comparisons between age groups, none differed significantly by age group within each sample. It is concluded that the observed significant difference in pubic bone length in the Native American female skeletal samples cannot be replicated in other samples and that there is no age effect on pubic bone length in the samples tested in this analysis. Tague's findings reflect either the occurrence of late menarche in prehistoric populations or differential survivorship.
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Bashiri, Ghader; Rehan, Aisyah M.; Sreebhavan, Sreevalsan; Baker, Heather M.; Baker, Edward N.; Squire, Christopher J.
2016-01-01
Cofactor F420 is an electron carrier with a major role in the oxidoreductive reactions of Mycobacterium tuberculosis, the causative agent of tuberculosis. A γ-glutamyl ligase catalyzes the final steps of the F420 biosynthesis pathway by successive additions of l-glutamate residues to F420-0, producing a poly-γ-glutamate tail. The enzyme responsible for this reaction in archaea (CofE) comprises a single domain and produces F420-2 as the major species. The homologous M. tuberculosis enzyme, FbiB, is a two-domain protein and produces F420 with predominantly 5–7 l-glutamate residues in the poly-γ-glutamate tail. The N-terminal domain of FbiB is homologous to CofE with an annotated γ-glutamyl ligase activity, whereas the C-terminal domain has sequence similarity to an FMN-dependent family of nitroreductase enzymes. Here we demonstrate that full-length FbiB adds multiple l-glutamate residues to F420-0 in vitro to produce F420-5 after 24 h; communication between the two domains is critical for full γ-glutamyl ligase activity. We also present crystal structures of the C-terminal domain of FbiB in apo-, F420-0-, and FMN-bound states, displaying distinct sites for F420-0 and FMN ligands that partially overlap. Finally, we discuss the features of a full-length structural model produced by small angle x-ray scattering and its implications for the role of N- and C-terminal domains in catalysis. PMID:26861878
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NASA Astrophysics Data System (ADS)
Schmidt, Carl
2016-02-01
Neutral and ion species in cometary comae exhibit significant differences in their spatial distributions. These distributions reflect the combined effects of sublimation, ion pickup, collisions, solar radiation pressure, photolysis scale lengths of any parent molecules, and photolysis of the species of interest. An image-slicer spectrograph (R ∼ 20,000) is used here to measure C2, NH2, Na, and H2O+ emission lines in Comet C/2012 S1 ISON's coma within a narrow spectral window spanning 5868-5926 Å. These species are mapped over a 1.6 × 2.7 arcmin field made up of 240 individual spectra. While prior cometary observations have found that peak column densities of these species appear either sunward or anti-sunward, ISON's coma was elongated several thousand kilometers along an axis perpendicular to its motion and the sunward vector. The peak brightness of each species was located within 5000 km of the dusty continuum concentration. ISON's water ion tail appeared distinctly broader than the neutral Na tail and no evidence is seen for an extended source of Na by dissociative recombination of a molecular ion. The Na D2/D1 ratio in the head is 1.49 ± 0.06 despite being optically thin, increasing to 1.93 ± 0.07 in the tail. The dust distribution falls off less steeply than the canonical inverse with distance from the nucleus and C2 and NH2 scale lengths indicate an extended source, possibly due to nucleus fragmentation.
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Geminga's tails: a pulsar bow shock probing the interstellar medium.
Caraveo, P A; Bignami, G F; DeLuca, A; Mereghetti, S; Pellizzoni, A; Mignani, R; Tur, A; Becker, W
2003-09-05
We report the X-ray Multimirror Mission-Newton European Photon Imaging Camera observation of two elongated parallel x-ray tails trailing the pulsar Geminga. They are aligned with the object's supersonic motion, extend for approximately 2', and have a nonthermal spectrum produced by electron-synchrotron emission in the bow shock between the pulsar wind and the surrounding medium. Electron lifetime against synchrotron cooling matches the source transit time over the x-ray features' length. Such an x-ray detection of a pulsar bow shock (with no Halpha emission) allows us to gauge the pulsar electron injection energy and the shock magnetic field while constraining the angle of Geminga's motion and the local matter density.
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Reactions and Transport: Diffusion, Inertia, and Subdiffusion
NASA Astrophysics Data System (ADS)
Méndez, Vicenç; Fedotov, Sergei; Horsthemke, Werner
Particles, such as molecules, atoms, or ions, and individuals, such as cells or animals, move in space driven by various forces or cues. In particular, particles or individuals can move randomly, undergo velocity jump processes or spatial jump processes [333]. The steps of the random walk can be independent or correlated, unbiased or biased. The probability density function (PDF) for the jump length can decay rapidly or exhibit a heavy tail. Similarly, the PDF for the waiting time between successive jumps can decay rapidly or exhibit a heavy tail. We will discuss these various possibilities in detail in Chap. 3. Below we provide an introduction to three transport processes: standard diffusion, transport with inertia, and anomalous diffusion.
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Casal, Graça; Costa, Graça; Azevedo, Carlos
2007-09-01
The first ultrastructural description of Ceratomyxa tenuispora Kabata, 1960 (Myxozoa, Bivalvulida) from Madeira Island (Portugal), a parasite found in the gall bladder of the commercially important black-scabbard fish, Aphanopus carbo Lowe is presented. This parasite possesses spherical to ellipsoidal disporous trophozoites. Spores have a central crescent-shaped body averaging 11.0 microm in length, 28.5 microm in thickness and 12.1 microm in width. The valves have two long opposite lateral processes (ribbon-like structures or tails), each averaging 173 microm in length. The total thickness of the spore averages 375 microm. The spore has two sub-spherical polar capsules (approximately 5.2 x 4.1 microm), each with a polar filament with 7 to 8 coils. Some ultrastructural aspects of the sporogonic stages are described. The trophozoites develop without contact with epithelial cells. The cytoplasmic membrane has numerous evenly distributed external slender projections about 0.3 to 0.7 microm long. The sporogenesis produces two spores without pansporoblast formation. In the matrix of the capsular primordium, microtubules with an unusual organisation were observed. A binucleate sporoplasm that contains several sporoplasmosomes and dense bodies fills the spore cavity and extends to the tails without penetrating them.
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Langmuir-Gibbs Surface Phases and Transitions
NASA Astrophysics Data System (ADS)
Ocko, Benjamin; Sloutskin, Eli; Sapir, Zvi; Tamam, Lilach; Deutsch, Moshe; Bain, Colin
2007-03-01
Recent synchrotron x-ray measurements reveal surface ordering transitions in films of medium-length linear hydrocarbons (alkanes), spread on the water surface. Alkanes longer than hexane do not spread on the free surface of water. However, sub-mM concentrations of some anionic surfactants (e.g. CTAB) induce formation of thermodynamically stable alkane monolayers, through a ``pseudo-partial wetting'' phenomenon[1]. The monolayers, incorporating both water-insoluble alkanes (Langmuir) and water-soluble CTAB molecules (Gibbs) are called Langmuir-Gibbs (LG) films. The films formed by alkanes with n <=17 exhibit ordering transition upon cooling [2], below which the molecules are normal to the water surface and hexagonally packed, with CTAB molecules randomly mixed inside the quasi-2D crystal. Alkanes with n>17 can not form ordered LG monolayers, due to the repulsion from the n=16 tails of CTAB. This repulsion arises from the two chains' length mismatch. A demixing transition occurs upon ordering, with a pure alkane quasi-2D crystal forming on top of disordered alkyl tails of CTAB molecules. [1] K.M. Wilkinson et al., Chem. Phys. Phys. Chem. 6, 547 (2005). [2] E. Sloutskin, Z. Sapir, L. Tamam, B.M. Ocko, C.D. Bain, and M. Deutsch, Thin Solid Films, in press; K.M. Wilkinson, L. Qunfang, and C.D. Bain, Soft Matter 2, 66 (2006).
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Hydrophobic tail length plays a pivotal role in amyloid beta (25-35) fibril-surfactant interactions.
Bag, Sudipta; Chaudhury, Susmitnarayan; Pramanik, Dibyendu; DasGupta, Sunando; Dasgupta, Swagata
2016-09-01
The amyloid β-peptide fragment comprising residues 25-35 (Aβ25-35 ) is known to be the most toxic fragment of the full length Aβ peptide which undergoes fibrillation very rapidly. In the present work, we have investigated the effects of the micellar environment (cationic, anionic, and nonionic) on preformed Aβ25-35 fibrils. The amyloid fibrils have been prepared and characterized by several biophysical and microscopic techniques. Effects of cationic dodecyl trimethyl ammonium bromide (DTAB), cetyl trimethylammonium bromide (CTAB), anionic sodium dodecyl sulfate (SDS), and nonionic polyoxyethyleneoctyl phenyl ether (Triton X-100 or TX) on fibrils have been studied by Thioflavin T fluorescence, UV-vis spectroscopy based turbidity assay and microscopic analyses. Interestingly, DTAB and SDS micelles were observed to disintegrate prepared fibrils to some extent irrespective of their charges. CTAB micelles were found to break down the fibrillar assembly to a greater extent. On the other hand, the nonionic surfactant TX was found to trigger the fibrillation process. The presence of a longer hydrophobic tail in case of CTAB is assumed to be a reason for its higher fibril disaggregating efficacy, the premise of their formation being largely attributed to hydrophobic interactions. Proteins 2016; 84:1213-1223. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
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Fluorinated diglucose detergents for membrane-protein extraction.
Boussambe, Gildas Nyame Mendendy; Guillet, Pierre; Mahler, Florian; Marconnet, Anaïs; Vargas, Carolyn; Cornut, Damien; Soulié, Marine; Ebel, Christine; Le Roy, Aline; Jawhari, Anass; Bonneté, Françoise; Keller, Sandro; Durand, Grégory
2018-05-29
Fluorinated surfactants have scarcely been explored for the direct extraction of proteins from membranes because fluorination is believed to abrogate detergency. However, we have recently shown that a commercially available fluorinated surfactant readily solubilizes lipid membranes, thereby suggesting that fluorination per se does not interfere with detergent activity. In this work, we developed new fluorinated surfactants that exhibit detergency in terms of both lipid-vesicle solubilization and membrane-protein extraction. The compounds made and tested contain two glucose moieties as polar headgroup, a hydrogenated thioether linker, and a perfluorinated alkyl tail with either 4, 6, or 8 carbon atoms. The physicochemical properties of the micelles formed by the three fluorinated surfactants were evaluated by NMR spectroscopy, surface tensiometry, isothermal titration calorimetry, dynamic light scattering, small-angle X-ray scattering, and analytical ultracentrifugation. At 25°C, micellization was mainly entropy-driven, and the CMC values were found to decrease with chain length of the fluorinated tail, whereas the aggregation number increased with chain length. Remarkably, all three surfactants were found to solubilize lipid vesicles and extract a broad range of proteins from Escherichiacoli membranes. These findings demonstrate, for the first time, that nonionic fluorinated surfactants could be further exploited for the direct extraction and solubilization of membrane proteins. Copyright © 2018. Published by Elsevier Inc.
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El Didamony, Gamal; Askora, Ahmed; Shehata, Aya A
2015-06-01
In this study, two lytic phages designated as ϕPSZ1 and ϕPSZ2 infecting multidrug resistant Pseudomonas aeruginosa were isolated from sewage samples collected in Zagazig, Egypt. Morphological analysis by transmission electron microscopy revealed that both phages belong to the podoviridae family and resembles typical T7-like phages. ϕPSZ1 has a head of about 60 ± 5 nm in diameter with a short tail of 19 ± 2 nm in length, while ϕPSZ2 has a head of about 57 ± 5 nm in diameter with a short tail of 14 ± 2 nm in length. Both phages were shown to be able to infect 13 different P. aeruginosa strains and has no effect on other tested bacteria. In spite of morphological similarity, these phages showed diverged genomic sequences revealed by restriction enzyme digestion analysis. One-step growth curves of bacteriophages revealed eclipse and latent periods of 12 min for ϕPSZ1 and 15 min for ϕPSZ2, respectively, with burst sizes of about 100 per infected cell. Phage treatment prevented the growth of P. aeruginosa for up to 18 h with multiplicity of infection ratios of 1. These results suggest that both phages have a high potential for phage application to control P. aeruginosa.
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KAMIYA, Seitaro; OGASAWARA, Masayoshi; ARAKAWA, Masayuki; HAGIMORI, Masayori
2013-01-01
Thrombosis is characterized by congenital and acquired procatarxis. Lactic acid bacteria-fermented soybean milk products (FS-LAB) inhibit hepatic lipid accumulation and prevent atherosclerotic plaque formation. However, the therapeutic efficacy of FS-LAB against thrombosis has yet to be investigated. In this study, FS-LAB were administered subcutaneously into the tails of rats, with the subsequent intravenous administration of κ-carrageenan 12 hr after the initial injection. In general, administration of κ-carrageenan induces thrombosis. The length of the infarcted tail regions was significantly shorter in the rats administered a single-fold or double-fold concentration of the FS-LAB solution compared with the region in control rats. Therefore, FS-LAB exhibited significant antithrombotic effects. Our study is the first to characterize the properties of FS-LAB and, by testing their efficacy on an in vivo rat model of thrombosis, demonstrate the potency of their antithrombotic effect. PMID:24936368
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Wake structures behind a swimming robotic lamprey with a passively flexible tail
Leftwich, Megan C.; Tytell, Eric D.; Cohen, Avis H.; Smits, Alexander J.
2012-01-01
SUMMARY A robotic lamprey, based on the silver lamprey, Ichthyomyzon unicuspis, was used to investigate the influence of passive tail flexibility on the wake structure and thrust production during anguilliform swimming. A programmable microcomputer actuated 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform was based on kinematic studies of living lamprey, and the shape of the tail was taken from a computer tomography scan of the silver lamprey. The tail was constructed of flexible PVC gel, and nylon inserts were used to change its degree of flexibility. Particle image velocimetry measurements using three different levels of passive flexibility show that the large-scale structure of the wake is dominated by the formation of two pairs of vortices per shedding cycle, as seen in the case of a tail that flexed actively according to a pre-defined kinematic pattern, and did not bend in response to fluid forces. When the tail is passively flexible, however, the large structures are composed of a number of smaller vortices, and the wake loses coherence as the degree of flexibility increases. Momentum balance calculations indicate that, at a given tailbeat frequency, increasing the tail flexibility yields less net force, but changing the cycle frequency to match the resonant frequency of the tail increases the force production. PMID:22246250
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Nakajima, Keisuke; Tazawa, Ichiro; Yaoita, Yoshio
2018-02-01
Thyroid hormone (TH) binds TH receptor α (TRα) and β (TRβ) to induce amphibian metamorphosis. Whereas TH signaling has been well studied, functional differences between TRα and TRβ during this process have not been characterized. To understand how each TR contributes to metamorphosis, we generated TRα- and TRβ-knockout tadpoles of Xenopus tropicalis and examined developmental abnormalities, histology of the tail and intestine, and messenger RNA expression of genes encoding extracellular matrix-degrading enzymes. In TRβ-knockout tadpoles, tail regression was delayed significantly and a healthy notochord was observed even 5 days after the initiation of tail shortening (stage 62), whereas in the tails of wild-type and TRα-knockout tadpoles, the notochord disappeared after ∼1 day. The messenger RNA expression levels of genes encoding extracellular matrix-degrading enzymes (MMP2, MMP9TH, MMP13, MMP14, and FAPα) were obviously reduced in the tail tip of TRβ-knockout tadpoles, with the shortening tail. The reduction in olfactory nerve length and head narrowing by gill absorption were also affected. Hind limb growth and intestinal shortening were not compromised in TRβ-knockout tadpoles, whereas tail regression and olfactory nerve shortening appeared to proceed normally in TRα-knockout tadpoles, except for the precocious development of hind limbs. Our results demonstrated the distinct roles of TRα and TRβ in hind limb growth and tail regression, respectively. Copyright © 2018 Endocrine Society.
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Faragher, S G; Dalgarno, L
1986-07-20
The 3' untranslated (UT) sequences of the genomic RNAs of five geographic variants of the alphavirus Ross River virus (RRV) were determined and compared with the 3' UT sequence of RRV T48, the prototype strain. Part of the 3' UT region of Getah virus, a close serological relative of RRV, was also sequenced. The RRV 3' UT region varies markedly in length between variants. Large deletions or insertions, sequence rearrangements and single nucleotide substitutions are observed. A sequence tract of 49 to 58 nucleotides, which is repeated as four blocks in the RRV T48 3' UT region, occurs only once in the 3' UT region of one RRV strain (NB5092), indicating that the existence of repeat sequence blocks is not essential for RRV replication. However, the precise sequence of the 3' proximal copy of the repeat block and its position relative to the poly(A) tail were identical in all RRV isolates examined, suggesting that it has an important role in RRV replication. Nucleotide substitutions between RRV variants are distributed non-randomly along the length of the 3' UT region. The sequence of 120 to 130 nucleotides adjacent to the poly(A) tail is strongly conserved. Getah virus RNA contains three repeat sequence blocks in the 3' UT region. These are similar in sequence to those in RRV RNA but differ in their arrangement. Homology between the RRV and Getah 3' UT sequences is greatest in the 3' proximal repeat sequence block that shows three differences in 49 nucleotides. The 3' proximal repeat in Getah RNA occurs at the same position, relative to the poly(A) tail, as in all RRV variants. The RRV and Getah virus 3' UT sequences show extensive homology in the region between the 3' proximal repeat and the poly(A) tail but, apart from the repeat blocks themselves, they show no significant homology elsewhere.
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McAllister, Chris T.; Seville, R. Scott; Hartdegen, Ruston
2016-01-01
During May and June 2015, four common leaf-tailed geckos, Uroplatus fimbriatus (Schneider), five satanic leaf-tailed geckos, Uroplatus phantasticus (Boulenger), and four mossy leaf-tailed geckos, Uroplatus sikorae Boettger originally collected from Madagascar and housed at the Dallas Zoo, USA, had their faeces examined for coccidian parasites. Eight (62%) geckos were found to be passing oöcysts, including a new eimerian, a new isosporan and a previously described eimerian. Three of four (75%) U. fimbratus (type host) and one of five (20%) U. phantasticus were infected with Eimeria schneideri n. sp.; oöcysts were subspheroidal to ellipsoidal with a bi-layered wall and measured (length × width, L × W) 15.1 × 13.5 µm, with a length/width (L/W) ratio of 1.1. A micropyle and oöcyst residuum were absent but 1–many polar granules were present. Sporocysts were ovoidal, 6.9 × 5.3 µm, L/W 1.3. Stieda, sub-Stieda and para-Stieda bodies were absent. A globular sporocyst residuum was present as dispersed granules. Four of five (80%) U. phantasticus harbored Isospora boulengeri n. sp.; oöcysts were subpheroidal to ellipsoidal with a bi-layered wall and measured 17.3 × 16.0 µm, L/W 1.1. A micropyle and oöcyst residuum were absent but a polar granule was present. Sporocysts were ellipsoidal, 9.5 × 6.9 µm, L/W 1.4. Stieda and sub-Stieda bodies were present but a para-Stieda body was absent. A globular sporocyst residuum was present with dispersed granules. In addition, one of four (25%) U. sikorae was infected with an eimerian indistinguishable from Eimeria brygooi Upton and Barnard, 1987, previously reported from Madagascar day gecko, Phelsuma grandis Gray and golddust day gecko, Phelsuma laticauda (Boettger) from Madagascar. These are the first coccidians described from Uroplatus spp. PMID:27638735
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Gajski, Goran; Gerić, Marko; Oreščanin, Višnja; Garaj-Vrhovac, Vera
2013-01-20
In the present study the alkaline comet assay and the cytokinesis-block micronucleus cytome (CBMN Cyt) assay were used to evaluate the baseline frequency of cytogenetic damage in peripheral blood lymphocytes (PBLs) of 50 healthy children from the general population in Croatia (age, 11.62±1.81 years). Mean values of tail length, tail intensity and tail moment, as comet assay parameters, were 12.92±0.10, 0.73±0.06 and 0.08±0.01, respectively. The mean frequency of micronuclei (MN) for all subjects was 2.32±0.28 per 1000 bi-nucleated cells, while the mean frequency of nucleoplasmic bridges (NPBs) was 1.72±0.24 and of nuclear buds (NBUDs) 1.44±0.19. The mean nuclear division index (NDI) was 1.70±0.05. When comet-assay parameters were considered, higher mean values for all three were found for the female population. According to the Mann-Whitney U test applied on the results of the comet assay, the only statistically significant difference between the male and female populations was found for tail length. Similar to the results obtained by the comet assay, girls showed higher mean values of all three measured parameters of the CBMN Cyt assay. This difference was statistically significant for total number of NPBs only. In the case of the NDI, a higher mean value was also obtained in girls, but this difference was not statistically significant. The results obtained present background data that could be considered as normal values for healthy children living in urban areas, and can later on serve as baseline values for further toxicological monitoring. Additionally, the usefulness of both techniques in measuring cytogenetic damage during bio-monitoring of children is confirmed. Copyright © 2012 Elsevier B.V. All rights reserved.
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Handoo, Zafar A.; Carta, Lynn K.; Skantar, Andrea M.; Subbotin, Sergei A.; Fraedrich, Stephen W.
2016-01-01
A population of Xiphinema chambersi from the root zone around live oak (Quercus virginiana Mill.) trees on Jekyll Island, GA, is described using both morphological and molecular tools and compared with descriptions of type specimens. Initially, because of a few morphological differences, this nematode was thought to represent an undescribed species. However, on further examination, the morphometrics of the nematodes from live oak tend to agree with most of the morphometrics in the original description and redescription of X. chambersi except for few minor differences in V% relative to body length, slightly shorter stylet length, different c value, and the number of caudal pores. We consider these differences to be part of the normal variation within this species and accordingly image this new population of X. chambersi and redescribe the species. The new population is characterized by having females with a body length of 2.1 to 2.5 mm; lip region slightly rounded and set off from head; total stylet length 170 to 193 µm; vulva at 20.4% to 21.8% of body length; a monodelphic, posterior reproductive system; elongate, conoid tail with a blunt terminus and four pairs of caudal pores, of which two pairs are subdorsal and two subventral. Sequence data from the D2–D3 region of the 28S rRNA molecule subjected to GenBank sequence comparison using BLAST showed that the sequence had 96% and 99% similarity with X. chambersi from Alabama and Florida, respectively. Phylogenetic relationships of X. chambersi with other xiphinematids based on analysis of this DNA fragment are presented. This finding represents a new location of X. chambersi in Georgia on live oak for this species. PMID:27168649
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Fundamental Characterization of the Micellar Self-Assembly of Sophorolipid Esters.
Koh, Amanda; Todd, Katherine; Sherbourne, Ezekiel; Gross, Richard A
2017-06-13
Surfactants are ubiquitous constituents of commercial and biological systems that function based on complex structure-dependent interactions. Sophorolipid (SL) n-alkyl esters (SL-esters) comprise a group of modified naturally derived glycolipids from Candida bombicola. Herein, micellar self-assembly behavior as a function of SL-ester chain length was studied. Surface tensions as low as 31.2 mN/m and critical micelle concentrations (CMCs) as low as 1.1 μM were attained for diacetylated SL-decyl ester (dASL-DE) and SL-octyl ester, respectively. For deacetylated SL-esters, CMC values reach a lower limit at SL-ester chains above n-butyl (SL-BE, 1-3 μM). This behavior of SL-esters with increasing hydrophobic tail length is unlike other known surfactants. Diffusion-ordered spectroscopy (DOSY) and T 1 relaxation NMR experiments indicate this behavior is due to a change in intramolecular interactions, which impedes the self-assembly of SL-esters with chain lengths above SL-BE. This hypothesis is supported by micellar thermodynamics where a disruption in trends occurs at n-alkyl ester chain lengths above those of SL-BE and SL-hexyl ester (SL-HE). Diacetylated (dA) SL-esters exhibit an even more unusual trend in that CMC increases from 1.75 to 815 μM for SL-ester chain lengths of dASL-BE and dASL-DE, respectively. Foaming studies, performed to reveal the macroscopic implications of SL-ester micellar behavior, show that the observed instability in foams formed using SL-esters are due to coalescence, which highlights the importance of understanding intermicellar interactions. This work reveals that SL-esters are an important new family of green high-performing surfactants with unique structure-property relationships that can be tuned to optimize micellar characteristics.
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Sharma, Bibek; Patino, R.
2009-01-01
Xenopus laevis larvae were exposed to cadmium (Cd) at 0, 1, 8, 85 or 860 ??g L-1 in FETAX medium from 0 to 86 d postfertilization. Premetamorphic tadpoles were sampled on day 31; pre and prometamorphic tadpoles on day 49; and frogs (NF stage 66) between days 50 and 86. Survival, snout-vent length (SVL), tail length, total length, hindlimb length (HLL), initiation of metamorphic climax, size at and completion of metamorphosis, and gonadal condition and sex ratio (assessed histologically) were determined. Survival was unaffected by Cd until day 49, but increased mortality was observed after day 49 at 860 ??g Cd L-1. On day 31, when tadpoles were in early premetamorphosis, inhibitory effects on tadpole growth were observed only at 860 ??g Cd L-1. On day 49, when most tadpoles where in late premetamorphosis/early prometamorphosis, reductions in SVL, HLL and total length were observed at 8 and 860 but not 85 ??g L-1, thus creating a U-shaped size distribution at 0-85 ??g Cd L-1. However, this U-shaped size pattern was not evident in postmetamorphic individuals. In fact, frog size at completion of metamorphosis was slightly smaller at 85 ??g Cd L-1relative to control animals. These observations confirmed a recent report of a Cd concentration-dependent bimodal growth pattern in late-premetamorphic Xenopus tadpoles, but also showed that growth responses to varying Cd concentrations change with development. The fraction of animals initiating or completing metamorphosis during days 50-86 was reduced in a Cd concentration-dependent manner. Testicular histology and population sex ratios were unaffected by Cd suggesting that, unlike mammals, Cd is not strongly estrogenic in Xenopus tadpoles. ?? 2009 Elsevier Ltd.
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Sharma, Bibek; Patino, Reynaldo
2009-01-01
Xenopus laevis larvae were exposed to cadmium (Cd) at 0, 1, 8. 85 or 860 mu g L(-1) in FETAX medium from 0 to 86 d postfertilization. Premetamorphic tadpoles were sampled on day 3 1; pre and prometamorphic tadpoles on day 49; and frogs (NF stage 66) between days 50 and 86. Survival, snout-vent length (SVL), tail length, total length, hindlimb length (HLL), initiation of metamorphic climax, size at and completion of metamorphosis, and gonadal condition and sex ratio (assessed histologically) were determined. Survival was unaffected by Cd until day 49, but increased mortality was observed after day 49 at 860 mu g Cd L(-1). On day 31, when tadpoles were in early premetamorphosis, inhibitory effects on tadpole growth were observed only at 860 mu g Cd L(-1). On day 49, when most tadpoles where in late premetamorphosis/early prometamorphosis, reductions in SVL, HLL and total length were observed at 8 and 860 but not 85 mu g L(-1), thus creating a U-shaped size distribution at 0-85 mu g Cd L(-1). However, this U-shaped size pattern was not evident in postmetamorphic individuals. In fact, frog size at completion of metamorphosis was slightly smaller at 85 mu g Cd L(-1) relative to control animals. These observations confirmed a recent report of a Cd concentration-dependent bimodal growth pattern in late-premetamorphic Xenopus tadpoles, but also showed that growth responses to varying Cd concentrations change with development. The fraction of animals initiating or completing metamorphosis during days 50-86 was reduced in a Cd concentration-dependent manner. Testicular histology and population sex ratios were unaffected by Cd suggesting that, unlike mammals, Cd is not strongly estrogenic in Xenopus tadpoles.
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Within-Event and Between-Events Ground Motion Variability from Earthquake Rupture Scenarios
NASA Astrophysics Data System (ADS)
Crempien, Jorge G. F.; Archuleta, Ralph J.
2017-09-01
Measurement of ground motion variability is essential to estimate seismic hazard. Over-estimation of variability can lead to extremely high annual hazard estimates of ground motion exceedance. We explore different parameters that affect the variability of ground motion such as the spatial correlations of kinematic rupture parameters on a finite fault and the corner frequency of the moment-rate spectra. To quantify the variability of ground motion, we simulate kinematic rupture scenarios on several vertical strike-slip faults and compute ground motion using the representation theorem. In particular, for the entire suite of rupture scenarios, we quantify the within-event and the between-events ground motion variability of peak ground acceleration (PGA) and response spectra at several periods, at 40 stations—all approximately at an equal distance of 20 and 50 km from the fault. Both within-event and between-events ground motion variability increase when the slip correlation length on the fault increases. The probability density functions of ground motion tend to truncate at a finite value when the correlation length of slip decreases on the fault, therefore, we do not observe any long-tail distribution of peak ground acceleration when performing several rupture simulations for small correlation lengths. Finally, for a correlation length of 6 km, the within-event and between-events PGA log-normal standard deviations are 0.58 and 0.19, respectively, values slightly smaller than those reported by Boore et al. (Earthq Spectra, 30(3):1057-1085, 2014). The between-events standard deviation is consistently smaller than the within-event for all correlations lengths, a feature that agrees with recent ground motion prediction equations.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Borreguero, Jose M.; Pincus, Philip A.; Sumpter, Bobby G.
Structure–property relationships of ionic block copolymer (BCP) surfactant complexes are critical toward the progress of favorable engineering design of efficient charge-transport materials. In this paper, molecular dynamics simulations are used to understand the dynamics of charged-neutral BCP and surfactant complexes. The dynamics are examined for two different systems: charged-neutral double-hydrophilic and hydrophobic–hydrophilic block copolymers with oppositely charged surfactant moieties. The dynamics of the surfactant head, tails, and charges are studied for five different BCP volume fractions. We observe that the dynamics of the different species solely depend on the balance between electrostatic and entropic interactions between the charged species andmore » the neutral monomers. The favorable hydrophobic–hydrophobic interactions and the unfavorable hydrophobic–hydrophilic interactions determine the mobilities of the monomers. The dynamical properties of the charge species influence complex formation. Structural relaxations exhibit length-scale dependent behavior, with slower relaxation at the radius of gyration length-scale and faster relaxation at the segmental length-scale, consistent with previous results. The dynamical analysis correlates ion-exchange kinetics to the self-assembly behavior of the complexes.« less
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Graphene nanoribbons on gold: understanding superlubricity and edge effects
NASA Astrophysics Data System (ADS)
Gigli, L.; Manini, N.; Benassi, A.; Tosatti, E.; Vanossi, A.; Guerra, R.
2017-12-01
We address the atomistic nature of the longitudinal static friction against sliding of graphene nanoribbons (GNRs) deposited on gold, a system whose structural and mechanical properties have been recently the subject of intense experimental investigation. By means of numerical simulations and modeling we show that the GNR interior is structurally lubric (‘superlubric’) so that the static friction is dominated by the front/tail regions of the GNR, where the residual uncompensated lateral forces arising from the interaction with the underneath gold surface opposes the free sliding. As a result of this edge pinning the static friction does not grow with the GNR length, but oscillates around a fairly constant mean value. These friction oscillations are explained in terms of the GNR-Au(111) lattice mismatch: at certain GNR lengths close to an integer number of the beat (or moiré) length there is good force compensation and superlubric sliding; whereas close to half odd-integer periods there is significant pinning of the edge with larger friction. These results make qualitative contact with recent state-of-the-art atomic force microscopy experiment, as well as with the sliding of other different incommensurate systems.
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The bald and the beautiful: hairlessness in domestic dog breeds.
Parker, Heidi G; Harris, Alexander; Dreger, Dayna L; Davis, Brian W; Ostrander, Elaine A
2017-02-05
An extraordinary amount of genomic variation is contained within the chromosomes of domestic dogs, manifesting as dramatic differences in morphology, behaviour and disease susceptibility. Morphology, in particular, has been a topic of enormous interest as biologists struggle to understand the small window of dog domestication from wolves, and the division of dogs into pure breeding, closed populations termed breeds. Many traits related to morphology, including body size, leg length and skull shape, have been under selection as part of the standard descriptions for the nearly 400 breeds recognized worldwide. Just as important, however, are the minor traits that have undergone selection by fanciers and breeders to define dogs of a particular appearance, such as tail length, ear position, back arch and variation in fur (pelage) growth patterns. In this paper, we both review and present new data for traits associated with pelage including fur length, curl, growth, shedding and even the presence or absence of fur. Finally, we report the discovery of a new gene associated with the absence of coat in the American Hairless Terrier breed.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'. © 2016 The Authors.
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Morphology and sexual dimorphism of the many-lined skink in north central New Mexico
Hathcock, Charles D.; Wright, Marjorie Alys; Gonzales, Gilbert J.; ...
2015-08-01
In 2001 and 2002, a study of many-lined skinks ( Plestiodon multivirgatus) was conducted by Los Alamos National Laboratory biologists in north-central New Mexico to determine means and ranges for several morphological characters and to test for sexual dimorphism. Over both years, there were 539 new captures of many-lined skinks, which included 131 hatchlings. The earliest hatchling capture was on 19 June and the latest capture was on 31 August. Hatchling captures peaked on 1 August in 2001 and 6 August in 2002. The age class, sex, snout–vent length (SVL), tail length (TL), mass, head length (HL), and head widthmore » (HW) were recorded and individuals were released at the point of capture. Our results indicate that the SVL, mass, HL, and HW did not exhibit sexual dimorphism. The sex ratio was skewed toward females in this study. It is not known whether the many-lined skink has sexual determination based on environmental factors, but the data here suggest that more research is needed. From these observations, we supplement the limited existing knowledge on the morphology of this species.« less
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Morphology and sexual dimorphism of the many-lined skink in north central New Mexico
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hathcock, Charles D.; Wright, Marjorie Alys; Gonzales, Gilbert J.
In 2001 and 2002, a study of many-lined skinks ( Plestiodon multivirgatus) was conducted by Los Alamos National Laboratory biologists in north-central New Mexico to determine means and ranges for several morphological characters and to test for sexual dimorphism. Over both years, there were 539 new captures of many-lined skinks, which included 131 hatchlings. The earliest hatchling capture was on 19 June and the latest capture was on 31 August. Hatchling captures peaked on 1 August in 2001 and 6 August in 2002. The age class, sex, snout–vent length (SVL), tail length (TL), mass, head length (HL), and head widthmore » (HW) were recorded and individuals were released at the point of capture. Our results indicate that the SVL, mass, HL, and HW did not exhibit sexual dimorphism. The sex ratio was skewed toward females in this study. It is not known whether the many-lined skink has sexual determination based on environmental factors, but the data here suggest that more research is needed. From these observations, we supplement the limited existing knowledge on the morphology of this species.« less
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Protein requirements for Blue-fronted Amazon (Amazona aestiva) growth.
Carciofi, A C; Sanfilippo, L F; de-Oliveira, L D; do Amaral, P P; Prada, F
2008-06-01
The objective of this study was to evaluate the protein requirements for hand-rearing Blue-fronted Amazon parrots (Amazona aestiva). Forty hatchlings were fed semi-purified diets containing one of four (as-fed basis) protein levels: 13%, 18%, 23% and 28%. The experiment was carried out in a randomized block design with the initial weight of the nestling as the blocking factor and 10 parrots per protein level. Regression analysis was used to determine relationships between protein level and biometric measurements. The data indicated that 13% crude protein supported nestling growth with 18% being the minimum tested level required for maximum development. The optimal protein concentration for maximum weight gain was 24.4% (p = 0.08; r(2) = 0.25), tail length 23.7% (p = 0.09; r(2) = 0.19), wing length 23.0% (p = 0.07; r(2) = 0.17), tarsus length 21.3% (p = 0.06; r(2) = 0.10) and tarsus width 21.4% (p = 0.07; r(2) = 0.09). Tarsus measurements were larger in males (p < 0.05), indicating that sex must be considered when studying developing psittacines. These results were obtained using a highly digestible protein and a diet with moderate metabolizable energy levels.
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Tracking of plus-ends reveals microtubule functional diversity in different cell types
NASA Astrophysics Data System (ADS)
Shaebani, M. Reza; Pasula, Aravind; Ott, Albrecht; Santen, Ludger
2016-07-01
Many cellular processes are tightly connected to the dynamics of microtubules (MTs). While in neuronal axons MTs mainly regulate intracellular trafficking, they participate in cytoskeleton reorganization in many other eukaryotic cells, enabling the cell to efficiently adapt to changes in the environment. We show that the functional differences of MTs in different cell types and regions is reflected in the dynamic properties of MT tips. Using plus-end tracking proteins EB1 to monitor growing MT plus-ends, we show that MT dynamics and life cycle in axons of human neurons significantly differ from that of fibroblast cells. The density of plus-ends, as well as the rescue and catastrophe frequencies increase while the growth rate decreases toward the fibroblast cell margin. This results in a rather stable filamentous network structure and maintains the connection between nucleus and membrane. In contrast, plus-ends are uniformly distributed along the axons and exhibit diverse polymerization run times and spatially homogeneous rescue and catastrophe frequencies, leading to MT segments of various lengths. The probability distributions of the excursion length of polymerization and the MT length both follow nearly exponential tails, in agreement with the analytical predictions of a two-state model of MT dynamics.
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Borreguero, Jose M.; Pincus, Philip A.; Sumpter, Bobby G.; ...
2017-06-21
Structure–property relationships of ionic block copolymer (BCP) surfactant complexes are critical toward the progress of favorable engineering design of efficient charge-transport materials. In this paper, molecular dynamics simulations are used to understand the dynamics of charged-neutral BCP and surfactant complexes. The dynamics are examined for two different systems: charged-neutral double-hydrophilic and hydrophobic–hydrophilic block copolymers with oppositely charged surfactant moieties. The dynamics of the surfactant head, tails, and charges are studied for five different BCP volume fractions. We observe that the dynamics of the different species solely depend on the balance between electrostatic and entropic interactions between the charged species andmore » the neutral monomers. The favorable hydrophobic–hydrophobic interactions and the unfavorable hydrophobic–hydrophilic interactions determine the mobilities of the monomers. The dynamical properties of the charge species influence complex formation. Structural relaxations exhibit length-scale dependent behavior, with slower relaxation at the radius of gyration length-scale and faster relaxation at the segmental length-scale, consistent with previous results. The dynamical analysis correlates ion-exchange kinetics to the self-assembly behavior of the complexes.« less
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Analytical Solution for Optimum Design of Furrow Irrigation Systems
NASA Astrophysics Data System (ADS)
Kiwan, M. E.
1996-05-01
An analytical solution for the optimum design of furrow irrigation systems is derived. The non-linear calculus optimization method is used to formulate a general form for designing the optimum system elements under circumstances of maximizing the water application efficiency of the system during irrigation. Different system bases and constraints are considered in the solution. A full irrigation water depth is considered to be achieved at the tail of the furrow line. The solution is based on neglecting the recession and depletion times after off-irrigation. This assumption is valid in the case of open-end (free gradient) furrow systems rather than closed-end (closed dike) systems. Illustrative examples for different systems are presented and the results are compared with the output obtained using an iterative numerical solution method. The final derived solution is expressed as a function of the furrow length ratio (the furrow length to the water travelling distance). The function of water travelling developed by Reddy et al. is considered for reaching the optimum solution. As practical results from the study, the optimum furrow elements for free gradient systems can be estimated to achieve the maximum application efficiency, i.e. furrow length, water inflow rate and cutoff irrigation time.
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Scott, Jamieson; Tong, Katie; William, Hamilton; ...
2014-10-31
The kinetics of aggregation of two pyromellitamide gelators; tetrabutyl- (C4) and tetrahexylpyromellitamide (C6), in deuterated cyclohexane has been investigated by small angle neutron scattering (SANS) for up to six days. The purpose of this study was to improve our understanding of how self-assembled gels are formed. Short-term (< 3 hour) time scales revealed multiple phases with the data for the tetrabutylpyromellitamide C4 indicating one dimensional stacking and aggregation corresponding to a multi-fiber braided cluster arrangement that is about 35 Å in diameter. The corresponding tetrahexylpyromellitamide C6 data suggests that the C6 also forms one-dimensional stacks but that these aggregate tomore » a thicker multi-fiber braided cluster that have a diameter of 61.8 Å. Over a longer period of time, the radius, persistence length and contour length all continue to increase in 6 days after cooling. This data suggests that structural changes in self-assembled gels occur over a period exceeding several days and that fairly subtle changes in the structure (e.g. tail-length) can influence the packing of molecules in self-assembled gels on the single-to-few fiber bundle stage.« less
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Jamieson, Scott A; Tong, Katie W K; Hamilton, William A; He, Lilin; James, Michael; Thordarson, Pall
2014-11-25
The kinetics of aggregation of two pyromellitamide gelators, tetrabutyl- (C4) and tetrahexyl-pyromellitamide (C6), in deuterated cyclohexane has been investigated by small angle neutron scattering (SANS) for up to 6 days. The purpose of this study was to improve our understanding of how self-assembled gels are formed. Short-term (< 3 h) time scales revealed multiple phases with the data for the tetrabutylpyromellitamide C4, indicating one-dimensional stacking and aggregation corresponding to a multifiber braided cluster arrangement that is about 35 Å in diameter. The corresponding tetrahexylpyromellitamide C6 data suggest that the C6 also forms one-dimensional stacks but that these aggregate to a thicker multifiber braided cluster that has a diameter of about 62 Å. Over a longer period of time, the radius, persistence length, and contour length all continue to increase in 6 days after cooling. These data suggest that structural changes in self-assembled gels occur over a period exceeding several days and that fairly subtle changes in the structure (e.g., tail-length) can influence the packing of molecules in self-assembled gels on the single-to-few fiber bundle stage.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Scott, Jamieson; Tong, Katie; William, Hamilton
The kinetics of aggregation of two pyromellitamide gelators; tetrabutyl- (C4) and tetrahexylpyromellitamide (C6), in deuterated cyclohexane has been investigated by small angle neutron scattering (SANS) for up to six days. The purpose of this study was to improve our understanding of how self-assembled gels are formed. Short-term (< 3 hour) time scales revealed multiple phases with the data for the tetrabutylpyromellitamide C4 indicating one dimensional stacking and aggregation corresponding to a multi-fiber braided cluster arrangement that is about 35 Å in diameter. The corresponding tetrahexylpyromellitamide C6 data suggests that the C6 also forms one-dimensional stacks but that these aggregate tomore » a thicker multi-fiber braided cluster that have a diameter of 61.8 Å. Over a longer period of time, the radius, persistence length and contour length all continue to increase in 6 days after cooling. This data suggests that structural changes in self-assembled gels occur over a period exceeding several days and that fairly subtle changes in the structure (e.g. tail-length) can influence the packing of molecules in self-assembled gels on the single-to-few fiber bundle stage.« less
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Lazinski, David W; Camilli, Andrew
2013-01-01
The amplification of DNA fragments, cloned between user-defined 5' and 3' end sequences, is a prerequisite step in the use of many current applications including massively parallel sequencing (MPS). Here we describe an improved method, called homopolymer tail-mediated ligation PCR (HTML-PCR), that requires very little starting template, minimal hands-on effort, is cost-effective, and is suited for use in high-throughput and robotic methodologies. HTML-PCR starts with the addition of homopolymer tails of controlled lengths to the 3' termini of a double-stranded genomic template. The homopolymer tails enable the annealing-assisted ligation of a hybrid oligonucleotide to the template's recessed 5' ends. The hybrid oligonucleotide has a user-defined sequence at its 5' end. This primer, together with a second primer composed of a longer region complementary to the homopolymer tail and fused to a second 5' user-defined sequence, are used in a PCR reaction to generate the final product. The user-defined sequences can be varied to enable compatibility with a wide variety of downstream applications. We demonstrate our new method by constructing MPS libraries starting from nanogram and sub-nanogram quantities of Vibrio cholerae and Streptococcus pneumoniae genomic DNA.
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Mondragón-Ceballos, R; García-Granados, M D; Matamoros-Trejo, G; Hernández-López, L E
2018-03-01
Although the breeding seasonality in Macaca arctoides have been studied over a long period of time, it is still controversial whether reproduction in this primate tend to increase during certain months of the year as it happens in most of the macaque species. Many authors have classified Macaca arctoides as not being seasonal species. Nonetheless, there were no reports, about seasonal variations of female sexual hormones to demonstrate that asseveration. Therefore, in the present study we collect 1611 fecal samples from June 2009 to November 2010 from 10 female stump-tailed macaques to measure 17β-estradiol and progesterone concentrations. Also, we included the birth frequency per year, in order to identify if sexual hormones peaked at a certain period of the year, thus, births would be occurring six months later according to the gestation length of stump-tailed macaques. Our results indicate two mating seasons per year in stump-tailed macaques: one in July-August and a second one in November. The distribution of the birth frequency, throughout the year support these results. We conclude that stump-tail macaques have a discrete seasonality no different than most of macaques' species. Copyright © 2017 Elsevier Inc. All rights reserved.
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Effect of Tail Surfaces on the Base Drag of a Body of Revolution at Mach Numbers of 1.5 and 2.0
NASA Technical Reports Server (NTRS)
Spahr, J Richard; Dickey, Robert R
1951-01-01
Wind-tunnel tests were performed at Mach numbers of 1.5 and 2.0 to investigate the influence of tail surfaces on the base drag of a body of revolution without boattailing and having a turbulent boundary layer. The tail surfaces were of rectangular plan form of aspect ratio 2.33 and has symmetrical, circular-arc airfoil section. The results of the investigation showed that the addition of these tail surfaces with the trailing edges at or near the body base incurred a large increase in the base-drag coefficient. For a cruciform tail having a 10-percent-thick airfoil section, this increase was about 70 percent at a Mach number of 1.5 and 35 percent at a Mach number of 2.0. As the trailing edge of the tail was moved forward or rearward of the base by about one tail-chord length, the base-drag increment was reduced to nearly zero. The increments in base-drag coefficient due to the presence of 10-percent-thick tail surfaces were generally twice those for 5-percent-thick surfaces. The base-drag increments due to the presence of a cruciform tail were less than twice those for a plane tail. An estimate of the change in base pressure due to the tail surfaces was made, based on a simple superposition of the airfoil-pressure field onto the base-pressure field behind the body. A comparison of the results with the experimental values indicated that in most cases the trend in the variation of the base-drag increment with changes in tail position could be predicted by this approximate method but that the quantitative agreement at most tail locations was poor.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pell, L.; Liu, A; Edmonds, L
The tail terminator protein (TrP) plays an essential role in phage tail assembly by capping the rapidly polymerizing tail once it has reached its requisite length and serving as the interaction surface for phage heads. Here, we present the 2.7-A crystal structure of a hexameric ring of gpU, the TrP of phage ?. Using sequence alignment analysis and site-directed mutagenesis, we have shown that this multimeric structure is biologically relevant and we have delineated its functional surfaces. Comparison of the hexameric crystal structure with the solution structure of gpU that we previously solved using NMR spectroscopy shows large structural changesmore » occurring upon multimerization and suggests a mechanism that allows gpU to remain monomeric at high concentrations on its own, yet polymerize readily upon contact with an assembled tail tube. The gpU hexamer displays several flexible loops that play key roles in head and tail binding, implying a role for disorder-to-order transitions in controlling assembly as has been observed with other ? morphogenetic proteins. Finally, we have found that the hexameric structure of gpU is very similar to the structure of a putative TrP from a contractile phage tail even though it displays no detectable sequence similarity. This finding coupled with further bioinformatic investigations has led us to conclude that the TrPs of non-contractile-tailed phages, such as ?, are evolutionarily related to those of contractile-tailed phages, such as P2 and Mu, and that all long-tailed phages may utilize a conserved mechanism for tail termination.« less
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In vivo analysis of polyadenylation in prokaryotes.
Mohanty, Bijoy K; Kushner, Sidney R
2014-01-01
Polyadenylation at the 3' ends of mRNAs, tRNAs, rRNAs, and sRNAs plays important roles in RNA metabolism in both prokaryotes and eukaryotes. However, the nature of poly(A) tails in prokaryotes is distinct compared to their eukaryotic counterparts. Specifically, depending on the organism, eukaryotic poly(A) tails average between 50 and >200 nt and can easily be isolated by several techniques involving oligo(dT)-dependent cDNA amplification. In contrast, the bulk of the poly(A) tails present on prokaryotic transcripts is relatively short (<10 nt) and is difficult to characterize using similar techniques. This chapter describes methods that can circumvent these problems. For example, we discuss how to isolate total RNA and characterize its overall polyadenylation status employing a poly(A) sizing assay. Furthermore, we describe a technique involving RNase H treatment of total RNA followed by northern analysis in order to distinguish length of poly(A) tails on various types of transcripts. Finally, we outline a useful procedure to clone the poly(A) tails of specific transcripts using 5'-3' end-ligated RNA, which is independent of oligo(dT)-dependent cDNA amplification. These approaches are particularly helpful in analyzing transcripts with either short or long poly(A) tails both in prokaryotes and eukaryotes.
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Norouzi, Davood; Katebi, Ataur; Cui, Feng; Zhurkin, Victor B.
2016-01-01
The spatial organization of nucleosomes in 30-nm fibers remains unknown in detail. To tackle this problem, we analyzed all stereochemically possible configurations of two-start chromatin fibers with DNA linkers L = 10–70 bp (nucleosome repeat length NRL = 157–217 bp). In our model, the energy of a fiber is a sum of the elastic energy of the linker DNA, steric repulsion, electrostatics, and the H4 tail-acidic patch interaction between two stacked nucleosomes. We found two families of energetically feasible conformations of the fibers—one observed earlier, and the other novel. The fibers from the two families are characterized by different DNA linking numbers—that is, they are topologically different. Remarkably, the optimal geometry of a fiber and its topology depend on the linker length: the fibers with linkers L = 10n and 10n + 5 bp have DNA linking numbers per nucleosome ΔLk ≈ −1.5 and −1.0, respectively. In other words, the level of DNA supercoiling is directly related to the length of the inter-nucleosome linker in the chromatin fiber (and therefore, to NRL). We hypothesize that this topological polymorphism of chromatin fibers may play a role in the process of transcription, which is known to generate different levels of DNA supercoiling upstream and downstream from RNA polymerase. A genome-wide analysis of the NRL distribution in active and silent yeast genes yielded results consistent with this assumption. PMID:28133628
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Heart position in snakes: response to "phylogeny, ecology, and heart position in snakes".
Lillywhite, Harvey B; Seymour, Roger S
2011-01-01
Here we comment on a recent article (Gartner et al. 2010 ) that addresses previous adaptive interpretations of heart position in the context of gravity effects on blood circulation of snakes. The authors used phylogenetically based statistical methods and concluded that both habitat and phylogeny influence heart position, which they contend is relatively more posterior in arboreal compared to terrestrial species. Their result is based on measurements of heart position relative to snout-vent length, rather than total body length as in previous studies. However, gravity acts on the total length of the arterial-venous vasculature, and caudal segments of continuous blood columns cannot be ignored. Arboreal snakes have relatively long tails; therefore anterior hearts appear to be more "posterior" when the position is described relative to a shorter trunk. There is no physiologically valid explanation for the alleged posterior heart position in arboreal snakes, and multiple lines of published evidence to the contrary are ignored. The authors secondarily evaluated their data set with estimates for total body length based on measurements from other taxa. They found no statistical difference between heart position in arboreal versus terrestrial species, yet their article implied otherwise. Gartner et al. ( 2010 ) contrasted "aquatic" and terrestrial species throughout their paper, and they claimed there is no correlation between heart position and habitat among "aquatic and terrestrial species." But they did not include any aquatic species in their data set. Therefore, the article confuses rather than promotes understanding of cardiovascular adaptation to gravity.
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Fadeeva, Natalia; Mordukhovich, Vladimir; Zograf, Julia
2016-05-02
Four new Campylaimus species are described from the deep-sea sediments of the Sea of Japan at depths of about 500‒3400 m. Campylaimus orientalis sp. nov. is characterized by having a body of moderate length, clearly annulated cuticle, a small rhomboid mouth opening which is displaced on the dorsal side of body, a gap between the unequal limbs of the amphid, prominent narrow longitudinal alae and cephalated spicules. Campylaimus minutus sp. nov. is characterized by having a cylindrical body, very weak annulations, amphids with a short dorsal limb (25-44% of pharynx length) and a ventral limb completely fused with lateral alae of equal width; and lateral alae extending from the base of the amphid to the tail tip. Campylaimus amphidialis sp. nov. is characterized by having the combination of a very long amphidial fovea occupying nearly the entire length of the pharynx; and a well defined boundary between the ventral amphid limb and lateral alae. The distinctive feature of Campylaimus pulcher sp. nov. is the elongated loop-shaped amphid with nearly equal parallel limbs and prominent narrow longitudinal alae; and cephalated spicules without a gubernaculum. The diagnosis of the genus Campylaimus is emended and an identification key to species, based mainly on form and length of amphidial fovea, width of lateral alae, and copulatory apparatus is given. The genus Campylaimus now includes nineteen valid species. Two species are considered as species inquirendae, mainly because of incomplete descriptions.
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Bolette, David P
2007-02-01
Oligacanthorhynchus nickoli n. sp. (Acanthocephala: Oligacanthorhynchidae) is described from the great-horned owl, Bubo virginianus (Gmelin, 1788) (type host), and red-tailed hawk, Buteojamaicensis (Gmelin, 1788), collected in central Arizona. The new species is most similar to Oligacanthorhynchus iheringi and Oligacanthorhynchus minor, but it differs from all congeners primarily by trunk length, proboscis size and armature, egg size, geographical range, and host species. It is distinguished from the 9 Oligacanthorhynchus species occurring in avian hosts from both the Western and Eastern Hemispheres. Descriptions of juvenile forms of O. nickoli from the intestine of B. jamaicensis are provided from recently ingested cystacanths with everted proboscides.
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NASA Astrophysics Data System (ADS)
Yamamoto, Masashi; Otsuka, Takahiro; Orimo, Yoshinori; Maeda, Tomoki; Hotta, Atsushi
Peptide amphiphiles (PA) possess nanoscale micelle structures and excellent biocompatibility. In aqueous PA solution, PA molecules can self-assemble through various configurations into spherical and wormlike micelles, which can occasionally form hydrogels. C16-W3K is one of the unique PA, whose micelle configurations can transfer from spherical to wormlike structures in its aqueous solution over time, while the wormlike micelles could also lead to gelation. In our recent research, the effects of the length of the hydrophobic alkyl tail and other external factors of C16-W3K on the gelation behavior of the C16-W3K solution have been discussed. It has been revealed that longer alkyl-tails could facilitate the gelation of the C16-W3K solution, and that the external stimuli, such as mechanical shear and heat, could promote faster gelation of the C16-W3K solution. It was also found that salt could adjust the pH of the C16-W3K solution, having profound influence on the gelation behavior of the C16-W3K solution. In fact, the gelation of the C16-W3K with a higher storage modulus could be obtained from relatively acidic solutions, while the gelation of the C16-W3K solution was firmly suppressed in highly basic solutions. This work was supported by a Grant-in-Aid for Scientific Research (A) (No. 15H02298 to A.H.) and a Grant-in-Aid for Research Activity Start-up (No.15H06586 to T.M.) from JSPS: KAKENHI.
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NASA Astrophysics Data System (ADS)
Leung, Cheuk Yui Curtis
Charged amphiphilic molecules can self-assemble into a large variety of objects including membranes, vesicles and fibers. These micro to nano-scale structures have been drawing increasing attention due to their broad applications, especially in biotechnology and biomedicine. In this dissertation, three self-assembled systems were investigated: +3/-1 self-assembled catanionic membranes, +2/-1 self-assembled catanionic membranes and +1 self-assembled nanofibers. Transmission electron microscopy (TEM) combined with synchrotron small and wide angle x-ray scattering (SAXS and WAXS) were used to characterize the coassembled structures from the mesoscopic to nanometer scale. We designed a system of +3 and -1 ionic amphiphiles that coassemble into crystalline ionic bilayer vesicles with large variety of geometries that resemble polyhedral cellular crystalline shells and archaea wall envelopes. The degree of ionization of the amphiphiles and their intermolecular electrostatic interactions can be controlled by varying pH. The molecular packing of these membranes showed a hexagonal to rectangular-C to hexagonal phase transition with increasing pH, resulting in significant changes to the membrane morphology. A similar mixture of +2 and -1 ionic amphiphiles was also investigated. In addition to varying pH, which controls the headgroup attractions, we also adjust the tail length of the amphiphiles to control the van der Waals interactions between the tails. A 2D phase diagram was developed to show how pH and tail length can be used to control the intermolecular packing within the membranes. Another system of self-assembled nanofiber network formed by positively charged amphiphiles was also studied. These highly charged fibers repel each other and are packed in hexagonal lattice with lattice constant at least eight times of the fiber diameter. The d-spacing and the crystal structure can be controlled by varying the solution concentration and temperature.
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Granular controls on the dispersion of bed load tracers
NASA Astrophysics Data System (ADS)
Jerolmack, D. J.; Martin, R. L.; Phillips, C. B.
2014-12-01
Coarse particles are transported in a river as bed load, i.e., they move in frequent contact with and are supported by the granular bed. This movement is typically intermittent and may be described by a series of steps are rests, the distributions of which determine particle dispersion. Laboratory and field studies of bed load tracer dispersion have reported sub- and super-diffusive behavior, both of which have been successfully reproduced with stochastic transport models. Although researchers have invoked heavy-tailed step lengths as the cause of anomalous dispersion, most observations report thin-tailed distributions. Little attention has been paid to rest periods, and stochastic transport models have not been connected to the underlying mechanics of particle motion. Based on theoretical and experimental evidence, we argue that step lengths are thin-tailed and do not control the longterm dispersion of bed load tracers; they are determined by momentum balance between the fluid and solid. Using laboratory experiments with both marbles and natural sediments, we demonstrate that the rest time distribution is power law, and argue that this distribution controls asymptotic dispersion. Observed rest times far exceed any hydrodynamic timescale. Experiments reveal that rest times of deposited particles are governed by fluctuations in river bed elevation; in particular, the return time for the bed to scour to the base of a deposited particle. Stochastic fluctuations in bed elevation are describable by an Ornstein-Uhlenbeck (mean-reverting random walk) model that contains two parameters, which we show are directly related to the granular shear rate and range of bed elevation fluctuations, respectively. Combining these results with the theory of asymmetric random walks (particles only move downstream), we predict superdiffusive behavior that is in quantitative agreement with our observations of tracer dispersion in a natural river.
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Liu, Zhongle; Myers, Lawrence C
2017-11-01
The human fungal pathogen Candida albicans develops drug resistance after long-term exposure to azole drugs in the treatment of chronic candidiasis. Gain-of-function (GOF) mutations in the transcription factor Tac1 and the consequent expression of its targets, drug efflux pumps Cdr1 and Cdr2, are a common mechanism by which C. albicans acquires fluconazole resistance. The mechanism by which GOF mutations hyperactivate Tac1 is currently unknown. Here, we define a transcriptional activation domain (TAD) at the C terminus of Tac1. GOF mutations within the Tac1 TAD, outside the context of full-length Tac1, generally do not enhance its absolute potential as a transcriptional activator. Negative regulation of the Tac1 TAD by the Tac1 middle region is necessary for the activating effect of GOF mutations or fluphenazine to be realized. We have found that full-length Tac1, when hyperactivated by xenobiotics or GOF mutations, facilitates the recruitment of the Mediator coactivator complex to the CDR1 promoter. Azole resistance and the activation of Tac1 target genes, such as CDR1 , are dependent on the Tac1 TAD and subunits of the Mediator tail module. The dependence of different Tac1 target promoters on the Mediator tail module, however, varies widely. Lastly, we show that hyperactivation of Tac1 is correlated with its Mediator-dependent phosphorylation, a potentially useful biomarker for Tac1 hyperactivation. The role of Mediator in events downstream of Tac1 hyperactivation in fluconazole-resistant clinical isolates is complex and provides opportunities and challenges for therapeutic intervention. Copyright © 2017 American Society for Microbiology.
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Azizi, Emanuel; Landberg, Tobias
2002-03-01
Although numerous studies have described the escape kinematics of fishes, little is known about the aquatic escape responses of salamanders. We compare the escape kinematics of larval and adult Eurycea bislineata, the two-lined salamander, to examine the effects of metamorphosis on aquatic escape performance. We hypothesize that shape changes associated with resorption of the larval tail fin at metamorphosis will affect aquatic locomotor performance. Escape responses were recorded using high-speed video, and the effects of life stage and total length on escape kinematics were analyzed statistically using analysis of covariance. Our results show that both larval and adult E. bislineata use a two-stage escape response (similar to the C-starts of fishes) that consists of a preparatory (stage 1) and a propulsive (stage 2) stroke. The duration of both kinematic stages and the distance traveled during stage 2 increased with total length. Both larval and adult E. bislineata had final escape trajectories that were directed away from the stimulus. The main kinematic difference between larvae and adults is that adults exhibit significantly greater maximum curvature during stage 1. Total escape duration and the distance traveled during stage 2 did not differ significantly between larvae and adults. Despite the significantly lower tail aspect ratio of adults, we found no significant decrease in the overall escape performance of adult E. bislineata. Our results suggest that adults may compensate for the decrease in tail aspect ratio by increasing their maximum curvature. These findings do not support the hypothesis that larvae exhibit better locomotor performance than adults as a result of stronger selective pressures on early life stages.
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Suliman Al-Gebaly, Asma
2017-01-01
Cadmium (Cd) is a non-essential metal whose dispersion in the environment has increased recently, Cd may enhance cell oxidative stress that leads to DNA damage and apoptotic cell death. The study aimed to evaluate the antioxidative capability of Burdock root 'Arctium lappa' on cadmium-induced oxidative stress and histopathology of the kidney of Wistar rats. Cadmium was applied in a form of cadmium chloride to three groups (15 mg Cd kg-1) for five weeks with two groups pre-treated with 'Arctium lappa' administration, 100 and 200 mg kg-1 b.wt. Data were analyzed using one way analysis of variance (ANOVA) followed by Least Significant Difference (LSD) test to determine the difference among means using the JMP version 12. Results revealed that cadmium induced a significant disorganization (p<0.05) of renal structure with collapsed tubular lamina and 76 μm tail length of the cells was observed, while histological sections of kidney pre-treated with 100 mg Arctium lappa kg-1 b.wt., showed a slightly less hypercellularity of glomerulus and reduction in the cell tail (59 μm). Furthermore, histological sections of kidney of rats pre-treated with 200 mg Arctium lappa kg-1 b.wt., showed high improvement of renal tubules and glomerulus with a prominent urinary space beside tail length of cells was recorded as 39 μm which was lower in comparison to other groups. Moreover, cadmium induced cellular destruction of the kidney was resumed with the pre-treatment of the secondary metabolites as an antioxidant compounds that produced from plant extracts. Arctium lappa leaf extract was efficient at both applied doses while 200 mg Arctium lappa kg-1 b.wt., had the most ameliorative effect.
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Modular structure of the full-length DNA gyrase B subunit revealed by small-angle X-ray scattering.
Costenaro, Lionel; Grossmann, J Günter; Ebel, Christine; Maxwell, Anthony
2007-03-01
DNA gyrase, the only topoisomerase able to introduce negative supercoils into DNA, is essential for bacterial transcription and replication; absent from humans, it is a successful target for antibacterials. From biophysical experiments in solution, we report a structural model at approximately 12-15 A resolution of the full-length B subunit (GyrB). Analytical ultracentrifugation shows that GyrB is mainly a nonglobular monomer. Ab initio modeling of small-angle X-ray scattering data for GyrB consistently yields a "tadpole"-like envelope. It allows us to propose an organization of GyrB into three domains-ATPase, Toprim, and Tail-based on their crystallographic and modeled structures. Our study reveals the modular organization of GyrB and points out its potential flexibility, needed during the gyrase catalytic cycle. It provides important insights into the supercoiling mechanism by gyrase and suggests new lines of research.
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PABP is not essential for microRNA-mediated translational repression and deadenylation in vitro
Fukaya, Takashi; Tomari, Yukihide
2011-01-01
MicroRNAs silence their complementary target genes via formation of the RNA-induced silencing complex (RISC) that contains an Argonaute (Ago) protein at its core. It was previously proposed that GW182, an Ago-associating protein, directly binds to poly(A)-binding protein (PABP) and interferes with its function, leading to silencing of the target mRNAs. Here we show that Drosophila Ago1-RISC induces silencing via two independent pathways: shortening of the poly(A) tail and pure repression of translation. Our data suggest that although PABP generally modulates poly(A) length and translation efficiency, neither PABP function nor GW182–PABP interaction is a prerequisite for these two silencing pathways. Instead, we propose that each of the multiple functional domains within GW182 has a potential for silencing, and yet they need to act together in the context of full-length GW182 to exert maximal silencing. PMID:22117217
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Identifying sex and age of akiapolaau
Pratt, T.K.; Fancy, S.G.; Harada, C.K.; Lindsey, G.D.; Jacobi, J.D.
1994-01-01
Methods for identifying the sex and age of the Akiapolaau (Hemignathus munroi), an endangered honeycreeper found only on the island of Hawaii, were developed by examination and measurement of 73 museum specimens and 24 live birds captured in mist nests. Akiapolaau probably undergo a single annual molt, with most birds molting between February and July. The mottled juvenal plumage is replaced by a first basic plumage characterized by yellowish-gray or yellowish-green underparts and often by retained wingbars. Male Akiapolaau may not attain adult plumage until their third molt. In adult females, only the throat and upper breast become yellow, whereas in adult males the superciliaries, cheeks, and entire underparts are yellow. Adult males have greater exposed culmen, gonys, wing chord, tail, and tarsus lengths than do females. Akiapolaau in first prebasic molt or older can be identified as to sex by culmen length, that of males being >23.4 mm.
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Two Universality Properties Associated with the Monkey Model of Zipf's Law
NASA Astrophysics Data System (ADS)
Perline, Richard; Perline, Ron
2016-03-01
The distribution of word probabilities in the monkey model of Zipf's law is associated with two universality properties: (1) the power law exponent converges strongly to $-1$ as the alphabet size increases and the letter probabilities are specified as the spacings from a random division of the unit interval for any distribution with a bounded density function on $[0,1]$; and (2), on a logarithmic scale the version of the model with a finite word length cutoff and unequal letter probabilities is approximately normally distributed in the part of the distribution away from the tails. The first property is proved using a remarkably general limit theorem for the logarithm of sample spacings from Shao and Hahn, and the second property follows from Anscombe's central limit theorem for a random number of i.i.d. random variables. The finite word length model leads to a hybrid Zipf-lognormal mixture distribution closely related to work in other areas.
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Scudder, R M; Burghardt, G M
1985-05-01
The effect of different feeding regimens on the growth pattern of Nerodia fasciata confluens was tested using a litter of 18 captive-born neonates. The snakes were divided among three feeding groups: one group fed once per week, another fed twice per week, and the third fed on alternate days. The once per week and the twice per week groups were offered the same weight of food each week, while the alternate-day group was offered food in excess of ingestion levels during each feeding session. The results indicate that there is a shift in the allocation of energy for growth in weight, snout-vent length, and tail length with a change in the feeding regimen. Females were affected more than the males. The results are discussed in relation to their possible effect on reproduction.
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A new species of Letheobia (Serpentes: Typhlopidae) from central Kenya.
Malonza, Patrick K; Bauer, Aaron M; Ngwava, Jacob M
2016-03-20
A new species of blind snake in the genus Letheobia (L. mbeerensis sp. nov.) is described from the Mbeere area on the extreme lower slopes of southeastern Mt. Kenya. It is an attenuate blind snake, superficially similar to Letheobia lumbriciformis but with 20 midbody scale rows and 670 middorsal scales. It has a total length of 280 mm with the proportionally longest tail in the genus (2.9% of total length), a broad rostral, eyes barely visible and in life it is pink in color. The new species is known from only a single specimen collected at Siakago, in Mbeere-Embu, which lies at an elevation of about 1200m. It is a burrowing species and like many other blind snakes it is likely to be nocturnal and rarely encountered on the soil surface. The new species is incorporated into a key to the scolecophidian snakes of Kenya.
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Interaction of cationic surfactants with DNA: a single-molecule study
Husale, Sudhir; Grange, Wilfried; Karle, Marc; Bürgi, Stephan; Hegner, Martin
2008-01-01
The interaction of cationic surfactants with single dsDNA molecules has been studied using force-measuring optical tweezers. For hydrophobic chains of length 12 and greater, pulling experiments show characteristic features (e.g. hysteresis between the pulling and relaxation curves, force-plateau along the force curves), typical of a condensed phase (compaction of a long DNA into a micron-sized particle). Depending on the length of the hydrophobic chain of the surfactant, we observe different mechanical behaviours of the complex (DNA-surfactants), which provide evidence for different binding modes. Taken together, our measurements suggest that short-chain surfactants, which do not induce any condensation, could lie down on the DNA surface and directly interact with the DNA grooves through hydrophobic–hydrophobic interactions. In contrast, long-chain surfactants could have their aliphatic tails pointing away from the DNA surface, which could promote inter-molecular interactions between hydrophobic chains and subsequently favour DNA condensation. PMID:18203749
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Tang, Xueming; Zou, Weizhong; Koenig, Peter H; McConaughy, Shawn D; Weaver, Mike R; Eike, David M; Schmidt, Michael J; Larson, Ronald G
2017-03-23
We link micellar structures to their rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling, as well as traditional surfactant packing arguments. The two body washes, namely, BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), cocamidopropyl betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body wash, whereas BW-1EO is an SLE1S-based body wash. Additional PRMs are also added into the body washes. The effects of temperature, salt, and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of the rheological data to predictions of the "Pointer Algorithm" [ Zou , W. ; Larson , R.G. J. Rheol. 2014 , 58 , 1 - 41 ], which is a simulation method based on the Cates model of micellar dynamics. Changes in these micellar properties are interpreted using the Israelachvili surfactant packing argument. From coarse-grained molecular simulations, we infer how salt modifies the micellar properties by changing the packing between the surfactant head groups, with the micellar radius remaining nearly constant. PRMs do so by partitioning to different locations within the micelles according to their octanol/water partition coefficient P OW and chemical structures, adjusting the packing of the head and/or tail groups, and by changing the micelle radius, in the case of a large hydrophobic PRM. We find that relatively hydrophilic PRMs with log P OW < 2 partition primarily to the head group region and shrink micellar length, decreasing viscosity substantially, whereas more hydrophobic PRMs, with log P OW between 2 and 4, mix with the hydrophobic surfactant tails within the micellar core and slightly enhance the viscosity and micelle length, which is consistent with the packing argument. Large and very hydrophobic PRMs, with log P OW > 4, are isolated deep inside the micelle, separating from the tails and swelling the radius of the micelle, leading to shorter micelles and much lower viscosities, leading eventually to swollen-droplet micelles.
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A Numerical Study of Vortex Dynamics of Flexible Wing Propulsors
2009-11-23
of validation. Figure 2 shows the streamline plot of the cylinder for Reynolds number of 40. The coefficient of drag and blob length is calculated to...Large amplitude lunate tail theory of fish locomotion. Journal of Fluid Mechanics 74, 161–182. Clough, R. W. & Penzein, J. 1993 Dynamics of...the swimming of slender fish . Journal of Fluid Mechanics 9, 305–317. Lighthill, M. J. 1970 Aquatic animal propulsion of high hydrodynamical efficiency
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NASA Technical Reports Server (NTRS)
1956-01-01
Convair JF-102A (54-1374) on the ramp at NACA High-Speed Flight Station , Edwards, California in 1956. The most prominent new feature distinguishing the JF-102A from the YF-102 was a longer fuselage with a pinched or 'coke-bottle' waist. Note wing-fences on both wings. The JF-102A Characteristics are: Wing Span, ft. 38.1 Fuselage length, ft. 63.4 Vertical Tail height, ft. 21.2 Power Plant: Pratt & Whitney J57-P-23 turbojet
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An integrated aerodynamic/propulsion study for generic aero-space planes based on waverider concepts
NASA Technical Reports Server (NTRS)
Rasmussen, M. L.; Emanuel, George
1989-01-01
The design of a unified aero-space plane based on waverider technology is analyzed. The overall aerodynamic design and performance of an aero-space plane are discussed in terms of the forebody, scramjet, and afterbody. Other subjects considered in the study are combustion/nozzle optimization, the idealized tip-to-tail waverider model, and the two-dimensional minimum length nozzle. Charts and graphs are provided to show the results of the preliminary investigations.
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Testosterone, Plumage Colouration and Extra-Pair Paternity in Male North-American Barn Swallows
Eikenaar, Cas; Whitham, Megan; Komdeur, Jan; van der Velde, Marco; Moore, Ignacio T.
2011-01-01
In most monogamous bird species, circulating testosterone concentration in males is elevated around the social female's fertile period. Variation in elevated testosterone concentrations among males may have a considerable impact on fitness. For example, testosterone implants enhance behaviours important for social and extra-pair mate choice. However, little is known about the relationship between natural male testosterone concentration and sexual selection. To investigate this relationship we measured testosterone concentration and sexual signals (ventral plumage colour and tail length), and determined within and extra-pair fertilization success in male North American barn swallows (Hirundo rustica erythrogaster). Dark rusty coloured males had higher testosterone concentrations than drab males. Extra-pair paternity was common (42% and 31% of young in 2009 and 2010, respectively), but neither within- nor extra-pair fertilization success was related to male testosterone concentration. Dark rusty males were less often cuckolded, but did not have higher extra-pair or total fertilization success than drab males. Tail length did not affect within- or extra-pair fertilization success. Our findings suggest that, in North American barn swallows, male testosterone concentration does not play a significant direct role in female mate choice and sexual selection. Possibly plumage colour co-varies with a male behavioural trait, such as aggressiveness, that reduces the chance of cuckoldry. This could also explain why dark males have higher testosterone concentrations than drab males. PMID:21853105
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A Long-Lived Oscillatory Space-Time Correlation Function of Two Dimensional Colloids
NASA Astrophysics Data System (ADS)
Kim, Jeongmin; Sung, Bong June
2014-03-01
Diffusion of a colloid in solution has drawn significant attention for a century. A well-known behavior of the colloid is called Brownian motion : the particle displacement probability distribution (PDPD) is Gaussian and the mean-square displacement (MSD) is linear with time. However, recent simulation and experimental studies revealed the heterogeneous dynamics of colloids near glass transitions or in complex environments such as entangled actin, PDPD exhibited the exponential tail at a large length instead of being Gaussian at all length scales. More interestingly, PDPD is still exponential even when MSD was still linear with time. It requires a refreshing insight on the colloidal diffusion in the complex environments. In this work, we study heterogeneous dynamics of two dimensional (2D) colloids using molecular dynamics simulations. Unlike in three dimensions, 2D solids do not follow the Lindemann melting criterion. The Kosterlitz-Thouless-Halperin-Nelson-Young theory predicts two-step phase transitions with an intermediate phase, the hexatic phase between isotropic liquids and solids. Near solid-hexatic transition, PDPD shows interesting oscillatory behavior between a central Gaussian part and an exponential tail. Until 12 times longer than translational relaxation time, the oscillatory behavior still persists even after entering the Fickian regime. We also show that multi-layered kinetic clusters account for heterogeneous dynamics of 2D colloids with the long-lived anomalous oscillatory PDPD.
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[Effect of electromagnetic pulse irradiation on mice reproduction].
Wang, Shui-ming; Wang, De-wen; Peng, Rui-yun; Chen, Hao-yu; Gao, Ya-bing; Cao, Xiao-zhe; Cui, Xue-mei; Zhao, Mei-lan
2003-10-01
To evaluate the effect of electromagnetic pulse (EMP) irradiation on mice reproduction. Female/male Kunming mice, 6 - 8 weeks old, prior to mating, or female after pregnancy were treated with whole body irradiation by 6 x 10(4) V/m electromagnetic pulse (EMP) for five times. The pregnant mice were killed on the 18th days, and teratological markers were analysed. EMP irradiation caused no significant changes in most of female organ weight and organ/body weight ratio. But it caused significant shortening in tail length of live foetus in the female mice before conception (prior to mating) or after pregnancy (P < 0.05), and obvious decrease in male offspring ratio (0.85 +/- 0.09 vs 1.09 +/- 0.17, P < 0.05). The male offspring ratio also significantly decreased (0.76 +/- 0.18 vs 1.09 +/- 0.17, P < 0.01) after male mice irradiated by EMP. The tail length of live foetus was shortened and male offspring sex ratio was increased after both male and female mice were irradiated by EMP. EMP irradiation also caused a significantly higher fetal death rate than normal control (P < 0.05). The embryo absorption rate was increased after irradiation except that was decreased in male mice. EMP irradiation has effect on pregnancy and offspring development in both male and female mice before mating and in female mice after pregnancy.
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The impact of medium architecture of alluvial settings on non-Fickian transport
Zhang, Yong; Green, Christopher T.; Fogg, Graham E.
2013-01-01
The influence of heterogeneous architecture of alluvial aquifers on non-Fickian transport is explored using the Monte Carlo approach. More than two thousand high-resolution hydrofacies models representing seven groups of alluvial settings are built to test the effects of varying facies proportions, mean length and its anisotropy ratio, juxtapositional tendencies, and sub-facies heterogeneity. Results show that the volumetric fraction (P(Z)) of floodplain layers classified by their thicknesses Z controls the non-Fickian tailing of tracer transport at late times. A simple quantitative relationship SBTC≈SP(Z)/2-1 is built based on a multi-rate mass transfer analysis, where SBTC is the slope of the power-law portion of tracer breakthrough curve, and SP(Z) denotes the slope of the power-law portion of the distribution of P(Z) which can be measured, e.g., in core logs. At early times, the mean length of hydrofacies affects the non-Fickian tailing by controlling the channeling of flow in high-permeability non-floodplain materials and the sequestration in surrounding low-permeability floodplain layers. The competition between channeling and sequestration generates complex pre-asymptotic features, including sublinear growth of plume mean displacement, superlinear growth of plume variance, and skewed mass distribution. Those observations of the influence of medium heterogeneity on tracer transport at early and late times may lead to development of nonlocal transport models that can be parameterized using measurable aquifer characteristics.
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Katarkar, Atul; Mukherjee, Sanjit; Khan, Masood H; Ray, Jay G; Chaudhuri, Keya
2014-09-01
Early detection and quantification of DNA damage in oral premalignancy or malignancy may help in management of the disease and improve survival rates. The comet assay has been successfully utilised to detect DNA damage in oral premalignant or malignancy. However, due to the invasive nature of collecting blood, it may be painful for many unwilling patients. This study compares the micronucleus (MN) assay in oral buccal mucosa cells with the comet assay in peripheral blood cells in a subset of oral habit-induced precancer and cancer patients. For this, MN assay of exfoliated epithelial cells was compared with comet assay of peripheral blood leucocytes among 260 participants, including those with oral lichen planus (OLP; n = 52), leukoplakia (LPK; n = 51), oral submucous fibrosis (OSF; n = 51), oral squamous cell carcinoma (OSCC; n = 54) and normal volunteers (n = 52). Among the precancer groups, LPK patients showed significantly higher levels of DNA damage as reflected by both comet tail length (P < 0.0001) and micronuclei (MNi) frequency (P = 0.0009). The DNA damage pattern in precancer and cancer patients was OLP < OSF < LPK < OSCC, and with respective oral habits, it was multiple habits > cigarette + khaini > cigarette smokers > areca + khaini > areca. There was no significant difference in the comet length and MNi frequency between males and females who had oral chewing habits. An overall significant correlation was observed between MNi frequency and comet tail length with r = 0.844 and P < 0.0001. Thus, the extent of DNA damage evaluation by the comet assay in peripheral blood cells is perfectly reflected by the MN assay on oral exfoliated epithelial cells, and MNi frequency can be used with the same effectiveness and greater efficiency in early detection of oral premalignant conditions. © The Author 2014. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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NASA Astrophysics Data System (ADS)
Crenshaw, Jasmine Davenport
2011-12-01
This dissertation examines two organic material systems, biotinylated microtubule filaments and thiophene. Biotinylated microtubule filaments partially coated with streptavidin and gliding on surface-adhered kinesin motor proteins converge to form linear "nanowire" and circular "nanospool" structures. We present a cellular automaton simulation tool that models the dynamics of microtubule gliding and interactions. In this method, each microtubule is composed of a head, body, and tail segments. The microtubule surface density, lengths, persistence length, and modes of interaction are dictated by the user. The microtubules are randomly arranged and move across a hexagonal lattice surface with the direction of motion of the head segment being determined probabilistically: the body and tail segments follow the path of the head. The analysis of the motion and interactions allow statistically meaningful data to be obtained regarding the number of generated spools, radial distribution in the distance between spools, and the average spool circumference lengths which can be compared to experimental results. This technique will aid in predictions of the formation process of nanowires and nanospools. Information regarding the kinetics and microstructure of any system can be extracted through this tool by the manipulation in the time and space dimensions. Chemical reactions of thiophene with organic molecules are of interest to chemically modify thermally deposited coatings or thin films of conductive polymers. Energy barriers are identified for reactive systems involving thiophene and small hydrocarbon radicals. The transition states for these reactive systems occurred through hydrogen abstraction. The results provide quantum mechanical level insights into the chemical processes that occur in the chemical modification processes described above, such as Surface Polymerization by Ion-Assisted Deposition (SPIAD), electropolymerization, and ion beam deposition. Enthalpies of formation are calculated for organic molecules using B3LYP, BMK, and B98 hybrid functionals. G3 and CBS-QB3 are used as standards in conjunction, due to their accurate thermochemistry parameters, with experimental values. The BMK functional proves to perform best with the selected organic molecules.
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Lambertz, Andreas; Schröder, Kai Michael; Schöb, Dominik Stefan; Binnebösel, Marcel; Anurov, Michael; Klinge, Uwe; Neumann, Ulf Peter; Klink, Christian Daniel
2015-01-01
Biocompatibility and tissue integration of a surgical suture are decisive factors for wound healing and therefore for the success of sutures. The optimal suture material is still under discussion. Polyvinylidene fluoride (PVDF) is described to have superior properties of biocompatibility and is therefore frequently used as a mesh component. Only little information is available about its use as a suture material. The aim of this study was to evaluate the biocompatibility of PVDF as a suture material in comparison to 5 different established sutures in a rat model. In 30 male rats, a monofilamental PVDF suture (Resopren®) and 5 established control suture materials [polyester (Miralene®), polytetrafluoroethylene (Gore®), poliglecaprone (Monocryl®), polydioxanone (Monoplus®), polyglactin 910 (Vicryl®), USP size 3-0] were placed in the subcutaneous layer of the abdominal wall without knot or tension. After 3, 7 or 21 days, the abdominal walls were explanted for histopathological and immunohistochemical investigation with special regard to the size and quality of foreign body granuloma and the length of the comet tail-like infiltrate (CTI). The PVDF sutures showed the smallest size of foreign body granuloma (60 ± 14 µm) and the smallest CTI length (343 ± 60 µm) of all polymers after 21 days. Only PVDF (Resopren) and polydioxanone (Monoplus) showed a significant collagen I/III ratio increase between days 3 and 21 (p = 0.009 and p = 0.016). The quality of foreign body reaction regarding inflammation, proliferation and fibrotic remodeling was similar between all suture materials. Our data indicate that monofilamental PVDF sutures show a favorable foreign body reaction with small granuloma sizes and CTI length in comparison to established sutures. Its use as a suture material in general surgery could therefore be extended in the future. To reinforce these findings, further clinical studies need to be conducted. 2015 S. Karger AG, Basel.
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Hannah, Stuart; Cardona, Javier; Lamprou, Dimitrios A; Šutta, Pavol; Baran, Peter; Al Ruzaiqi, Afra; Johnston, Karen; Gleskova, Helena
2016-09-28
Monolayers of six alkylphosphonic acids ranging from C8 to C18 were prepared by vacuum evaporation and incorporated into low-voltage organic field-effect transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). Similar to solution-assembled monolayers, the molecular order for vacuum-deposited monolayers improved with increasing length of the aliphatic tail. At the same time, Fourier transform infrared (FTIR) measurements suggested lower molecular coverage for longer phosphonic acids. The comparison of FTIR and vibration frequencies calculated by density functional theory indicated that monodentate bonding does not occur for any phosphonic acid. All monolayers exhibited low surface energy of ∼17.5 mJ/m(2) with a dominating Lifshitz-van der Waals component. Their surface roughness was comparable, while the nanomechanical properties were varied but not correlated to the length of the molecule. However, large improvement in transistor performance was observed with increasing length of the aliphatic tail. Upon going from C8 to C18, the mean threshold voltage decreased from -1.37 to -1.24 V, the field-effect mobility increased from 0.03 to 0.33 cm(2)/(V·s), the off-current decreased from ∼8 × 10(-13) to ∼3 × 10(-13) A, and for transistors with L = 30 μm the on-current increased from ∼3 × 10(-8) to ∼2 × 10(-6) A, and the on/off-current ratio increased from ∼3 × 10(4) to ∼4 × 10(6). Similarly, transistors with longer phosphonic acids exhibited much better air and bias-stress stability. The achieved transistor performance opens up a completely "dry" fabrication route for ultrathin dielectrics and low-voltage organic transistors.
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Sasaki, Daisuke; Fujihashi, Masahiro; Okuyama, Naomi; Kobayashi, Yukiko; Noike, Motoyoshi; Koyama, Tanetoshi; Miki, Kunio
2011-02-04
Hexaprenyl diphosphate synthase from Micrococcus luteus B-P 26 (Ml-HexPPs) is a heterooligomeric type trans-prenyltransferase catalyzing consecutive head-to-tail condensations of three molecules of isopentenyl diphosphates (C(5)) on a farnesyl diphosphate (FPP; C(15)) to form an (all-E) hexaprenyl diphosphate (HexPP; C(30)). Ml-HexPPs is known to function as a heterodimer of two different subunits, small and large subunits called HexA and HexB, respectively. Compared with homooligomeric trans-prenyltransferases, the molecular mechanism of heterooligomeric trans-prenyltransferases is not yet clearly understood, particularly with respect to the role of the small subunits lacking the catalytic motifs conserved in most known trans-prenyltransferases. We have determined the crystal structure of Ml-HexPPs both in the substrate-free form and in complex with 7,11-dimethyl-2,6,10-dodecatrien-1-yl diphosphate ammonium salt (3-DesMe-FPP), an analog of FPP. The structure of HexB is composed of mostly antiparallel α-helices joined by connecting loops. Two aspartate-rich motifs (designated the first and second aspartate-rich motifs) and the other characteristic motifs in HexB are located around the diphosphate part of 3-DesMe-FPP. Despite the very low amino acid sequence identity and the distinct polypeptide chain lengths between HexA and HexB, the structure of HexA is quite similar to that of HexB. The aliphatic tail of 3-DesMe-FPP is accommodated in a large hydrophobic cleft starting from HexB and penetrating to the inside of HexA. These structural features suggest that HexB catalyzes the condensation reactions and that HexA is directly involved in the product chain length control in cooperation with HexB.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Kenney, Jeffrey D. P.; Geha, Marla; Jáchym, Pavel
We present optical imaging and spectroscopy and H I imaging of the Virgo Cluster galaxy IC 3418, which is likely a 'smoking gun' example of the transformation of a dwarf irregular into a dwarf elliptical galaxy by ram pressure stripping. IC 3418 has a spectacular 17 kpc length UV-bright tail comprised of knots, head-tail, and linear stellar features. The only Hα emission arises from a few H II regions in the tail, the brightest of which are at the heads of head-tail UV sources whose tails point toward the galaxy ('fireballs'). Several of the elongated tail sources have Hα peaksmore » outwardly offset by ∼80-150 pc from the UV peaks, suggesting that gas clumps continue to accelerate through ram pressure, leaving behind streams of newly formed stars which have decoupled from the gas. Absorption line strengths, measured from Keck DEIMOS spectra, together with UV colors, show star formation stopped 300 ± 100 Myr ago in the main body, and a strong starburst occurred prior to quenching. While neither Hα nor H I emission are detected in the main body of the galaxy, we have detected 4 × 10{sup 7} M {sub ☉} of H I from the tail with the Very Large Array. The velocities of tail H II regions, measured from Keck LRIS spectra, extend only a small fraction of the way to the cluster velocity, suggesting that star formation does not happen in more distant parts of the tail. Stars in the outer tail have velocities exceeding the escape speed, but some in the inner tail should fall back into the galaxy, forming halo streams.« less
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Heavy Tail Behavior of Rainfall Extremes across Germany
NASA Astrophysics Data System (ADS)
Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.
2017-12-01
Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.
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Characterization of tail sheath protein of giant bacteriophage phiKZ Pseudomonas aeruginosa
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kurochkina, Lidia P., E-mail: lpk@ibch.r; Aksyuk, Anastasia A.; Sachkova, Maria Yu.
2009-12-20
The tail sheath protein of giant bacteriophage phiKZ Pseudomonas aeruginosa encoded by gene 29 was identified and its expression system was developed. Localization of the protein on the virion was confirmed by immunoelectron microscopy. Properties of gene product (gp) 29 were studied by electron microscopy, immunoblotting and limited trypsinolysis. Recombinant gp29 assembles into the regular tubular structures (polysheaths) of variable length. Trypsin digestion of gp29 within polysheaths or extended sheath of virion results in specific cleavage of the peptide bond between Arg135 and Asp136. However, this cleavage does not affect polymeric structure of polysheaths, sheaths and viral infectivity. Digestion bymore » trypsin of the C-truncated gp29 mutant, lacking the ability to self-assemble, results in formation of a stable protease-resistant fragment. Although there is no sequence homology of phiKZ proteins to proteins of other bacteriophages, some characteristic biochemical properties of gp29 revealed similarities to the tail sheath protein of bacteriophage T4.« less
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Xin, Lili; Wang, Jianshu; Guo, Sifan; Wu, Yanhu; Li, Xiaohai; Deng, Huaxin; Kuang, Dan; Xiao, Wei; Wu, Tangchun; Guo, Huan
2014-05-01
Coke oven emissions (COEs) containing various carcinogenic polycyclic aromatic hydrocarbons (PAHs) represent the coal-burning pollution in the air. Organic pollutants in the aerosol and particulate matter of COEs were collected from the bottom, side, and top of a coke oven. The Comet assay and cytokinesis-block micronucleus cytome assay were conducted to analyze the genetic damage of extractable organic matter (EOM) of COEs on HepG2 cells. All the three EOMs could induce significant dose-dependent increases in Olive tail moment, tail DNA, and tail length, micronuclei, nucleoplasmic bridges, and nuclear buds frequencies, which were mostly positively correlated with the total PAHs concentration in each EOM. In conclusion, EOMs of COEs in the three typical working places of coke oven can induce DNA strand breaks and genomic instability in the metabolically competent HepG2 cells. The PAHs in EOMs may be important causative agents for the genotoxic effects of COEs. Copyright © 2014 Elsevier B.V. All rights reserved.
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Zn(II)-dipicolylamine-based metallo-lipids as novel non-viral gene vectors.
Su, Rong-Chuan; Liu, Qiang; Yi, Wen-Jing; Zhao, Zhi-Gang
2017-08-01
In this study, a series of Zn(II)-dipicolylamine (Zn-DPA) based cationic lipids bearing different hydrophobic tails (long chains, α-tocopherol, cholesterol or diosgenin) were synthesized. Structure-activity relationship (SAR) of these lipids was studied in detail by investigating the effects of several structural aspects including the type of hydrophobic tails, the chain length and saturation degree. In addition, several assays were used to study their interactions with plasmid DNA, and results reveal that these lipids could condense DNA into nanosized particles with appropriate size and zeta-potentials. MTT-based cell viability assays showed that lipoplexes 5 had low cytotoxicity. The in vitro gene transfection studies showed the hydrophobic tails clearly affected the TE, and hexadecanol-containing lipid 5b gives the best TE, which was 2.2 times higher than bPEI 25k in the presence of 10% serum. The results not only demonstrate that these lipids might be promising non-viral gene vectors, but also afford us clues for further optimization of lipidic gene delivery materials.
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Congdon, Molly D; Childress, Elizabeth S; Patwardhan, Neeraj N; Gumkowski, James; Morris, Emily A; Kharel, Yugesh; Lynch, Kevin R; Santos, Webster L
2015-11-01
Sphingosine-1-phosphate (S1P) is a ubiquitous, endogenous small molecule that is synthesized by two isoforms of sphingosine kinase (SphK1 and 2). Intervention of the S1P signaling pathway has attracted significant attention because alteration of S1P levels is linked to several disease states including cancer, fibrosis, and sickle cell disease. While intense investigations have focused on developing SphK1 inhibitors, only a limited number of SphK2-selective agents have been reported. Herein, we report our investigations on the structure-activity relationship studies of the lipophilic tail region of SLR080811, a SphK2-selective inhibitor. Our studies demonstrate that the internal phenyl ring is a key structural feature that is essential in the SLR080811 scaffold. Further, we show the dependence of SphK2 activity and selectivity on alkyl tail length, suggesting a larger lipid binding pocket in SphK2 compared to SphK1. Copyright © 2015 Elsevier Ltd. All rights reserved.
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The search for new amphiphiles: synthesis of a modular, high-throughput library
Feast, George C; Lepitre, Thomas; Mulet, Xavier; Conn, Charlotte E; Hutt, Oliver E
2014-01-01
Summary Amphiphilic compounds are used in a variety of applications due to their lyotropic liquid-crystalline phase formation, however only a limited number of compounds, in a potentially limitless field, are currently in use. A library of organic amphiphilic compounds was synthesised consisting of glucose, galactose, lactose, xylose and mannose head groups and double and triple-chain hydrophobic tails. A modular, high-throughput approach was developed, whereby head and tail components were conjugated using the copper-catalysed azide–alkyne cycloaddition (CuAAC) reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and anomeric linkages. A library of 80 amphiphiles was subsequently produced, using a 24-vial array, with the majority formed in very good to excellent yields. A preliminary assessment of the liquid-crystalline phase behaviour is also presented. PMID:25161714
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The search for new amphiphiles: synthesis of a modular, high-throughput library.
Feast, George C; Lepitre, Thomas; Mulet, Xavier; Conn, Charlotte E; Hutt, Oliver E; Savage, G Paul; Drummond, Calum J
2014-01-01
Amphiphilic compounds are used in a variety of applications due to their lyotropic liquid-crystalline phase formation, however only a limited number of compounds, in a potentially limitless field, are currently in use. A library of organic amphiphilic compounds was synthesised consisting of glucose, galactose, lactose, xylose and mannose head groups and double and triple-chain hydrophobic tails. A modular, high-throughput approach was developed, whereby head and tail components were conjugated using the copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and anomeric linkages. A library of 80 amphiphiles was subsequently produced, using a 24-vial array, with the majority formed in very good to excellent yields. A preliminary assessment of the liquid-crystalline phase behaviour is also presented.
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Han, Gang; Chiappe, Luis M; Ji, Shu-An; Habib, Michael; Turner, Alan H; Chinsamy, Anusuya; Liu, Xueling; Han, Lizhuo
2014-07-15
Microraptorines are a group of predatory dromaeosaurid theropod dinosaurs with aerodynamic capacity. These close relatives of birds are essential for testing hypotheses explaining the origin and early evolution of avian flight. Here we describe a new 'four-winged' microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol Biota of China. With tail feathers that are nearly 30 cm long, roughly 30% the length of the skeleton, the new fossil possesses the longest known feathers for any non-avian dinosaur. Furthermore, it is the largest theropod with long, pennaceous feathers attached to the lower hind limbs (that is, 'hindwings'). The lengthy feathered tail of the new fossil provides insight into the flight performance of microraptorines and how they may have maintained aerial competency at larger body sizes. We demonstrate how the low-aspect-ratio tail of the new fossil would have acted as a pitch control structure reducing descent speed and thus playing a key role in landing.
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Lyu, Xiaolin; Xiao, Anqi; Zhang, Wei; Hou, Pingping; Gu, Kehua; Tang, Zhehao; Pan, Hongbing; Wu, Fan; Shen, Zhihao; Fan, Xinghe
2018-06-08
In this report, Im-3m and Pn-3m polymer cubosomes and p6mm polymer hexasomes are obtained through the self-assembly of a rod-coil amphiphilic block copolymer (ABCP). This is the first time that these structures are observed in a rod-coil system. By varying the hydrophobic chain length, the initial concentration of the polymer solution, or the solubility parameter of the mixed solvent, head-tail asymmetry is adjusted to control the formation of polymer cubosomes or hexasomes. The formation mechanism of the polymer cubosomes was also studied. This research opens up a new way for further study of the bicontinuous and inverse phases in different ABCP systems. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Ezquiaga, María C; Navone, Graciela T
2014-08-01
Moennigia celinae n. sp. collected from the small intestine of Chaetophractus vellerosus and Chaetophractus villosus (Xenarthra, Dasypodidae) from Argentina is herein described. This new species belongs to the genus Moennigia because it possesses a short uterus with few eggs, atrophied distal branch of the ovejector, vulva near the anus, and a conical tail. The new species has a synlophe with 17 symmetrical ridges and slight ventro-dorsal orientation. The spicule length:body length ratio is similar to that of the other species parasitic of Dasypodidae; however, Moennigia celinae n. sp. differs from Moennigia pintoi and Moennigia lutzi because the latter lack a gubernaculum, and from Moennigia complexus, Moennigia moennigi, Moennigia filamentosus, Moennigia intrusa, Moennigia littlei, Moennigia pulchra and Moennigia dessetae by the latter having very complex spicules with 2 or 3 points at the distal extremity. Moreover, Moennigia celinae n. sp. differs from Moennigia virilis by the length and shape of its spicules. Moennigia celinae n. sp. can be distinguished from Moennigia travassosi by the shape of the dorsal ray of the caudal bursa. Moennigia celinae n. sp. resembles Moennigia pseudopulchra but the gubernaculum of the latter is V-shaped. This is the second report of a species of Moennigia in Argentina and the first for the genus Chaetophractus.
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Savoian, Matthew S; Glover, David M
2010-03-01
The kinesin-8 proteins are a family of microtubule-depolymerising motor molecules, which, despite their highly conserved roles in chromosome alignment and spindle dynamics, remain poorly characterised. Here, we report that the Drosophila kinesin-8 protein, Klp67A, exists in two spatially and functionally separable metaphase pools: at kinetochores and along the spindle. Fixed and live-cell analyses of different Klp67A recombinant variants indicate that this kinesin-8 first collects at kinetochores during prophase and, by metaphase, localises to the kinetochore outerplate. Although the catalytic motor activity of Klp67A is required for efficient kinetochore recruitment at all times, microtubules are entirely dispensable for this process. The tail of Klp67A does not play a role in kinetochore accumulation, but is both necessary and sufficient for spindle association. Using functional assays, we reveal that chromosome position and spindle length are determined by the microtubule-depolymerising motor activity of Klp67A exclusively when located at kinetochores, but not along the spindle. These data reveal that, unlike other metazoan kinesin-8 proteins, Klp67A binds the nascent prophase and mature metaphase kinetochore. From this location, Klp67A uses its motor activity to ensure chromosome alignment and proper spindle length.
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Kutyavin, Igor V.
2013-01-01
Described in the article is a new approach for the sequence-specific detection of nucleic acids in real-time polymerase chain reaction (PCR) using fluorescently labeled oligonucleotide probes. The method is based on the production of PCR amplicons, which fold into dumbbell-like secondary structures carrying a specially designed ‘probe-luring’ sequence at their 5′ ends. Hybridization of this sequence to a complementary ‘anchoring’ tail introduced at the 3′ end of a fluorescent probe enables the probe to bind to its target during PCR, and the subsequent probe cleavage results in the florescence signal. As it has been shown in the study, this amplicon-endorsed and guided formation of the probe-target duplex allows the use of extremely short oligonucleotide probes, up to tetranucleotides in length. In particular, the short length of the fluorescent probes makes possible the development of a ‘universal’ probe inventory that is relatively small in size but represents all possible sequence variations. The unparalleled cost-effectiveness of the inventory approach is discussed. Despite the short length of the probes, this new method, named Angler real-time PCR, remains highly sequence specific, and the results of the study indicate that it can be effectively used for quantitative PCR and the detection of polymorphic variations. PMID:24013564
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RRE-dependent HIV-1 Env RNA effects on Gag protein expression, assembly and release
DOE Office of Scientific and Technical Information (OSTI.GOV)
López, Claudia S., E-mail: lopezcl@ohsu.edu; Sloan, Rachel; Cylinder, Isabel
The HIV-1 Gag proteins are translated from the full-length HIV-1 viral RNA (vRNA), whereas the envelope (Env) protein is translated from incompletely spliced Env mRNAs. Nuclear export of vRNAs and Env mRNAs is mediated by the Rev accessory protein which binds to the rev-responsive element (RRE) present on these RNAs. Evidence has shown there is a direct or indirect interaction between the Gag protein, and the cytoplasmic tail (CT) of the Env protein. Our current work shows that env gene expression impacts HIV-1 Gag expression and function in two ways. At the protein level, full-length Env expression altered Gag proteinmore » expression, while Env CT-deletion proteins did not. At the RNA level, RRE-containing Env mRNA expression reduced Gag expression, processing, and virus particle release from cells. Our results support models in which Gag is influenced by the Env CT, and Env mRNAs compete with vRNAs for nuclear export. - Highlights: • At the protein level, full-length HIV-1 Env alters Gag protein expression. • HIV-1 Env RNA expression reduces Gag levels and virus release. • Env RNA effects on Gag are dependent on the RRE. • RRE-containing Env RNAs compete with vRNAs for nuclear export.« less
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Hurrelbrink, R J; Nestorowicz, A; McMinn, P C
1999-12-01
An infectious cDNA clone of Murray Valley encephalitis virus prototype strain 1-51 (MVE-1-51) was constructed by stably inserting genome-length cDNA into the low-copy-number plasmid vector pMC18. Designated pMVE-1-51, the clone consisted of genome-length cDNA of MVE-1-51 under the control of a T7 RNA polymerase promoter. The clone was constructed by using existing components of a cDNA library, in addition to cDNA of the 3' terminus derived by RT-PCR of poly(A)-tailed viral RNA. Upon comparison with other flavivirus sequences, the previously undetermined sequence of the 3' UTR was found to contain elements conserved throughout the genus FLAVIVIRUS: RNA transcribed from pMVE-1-51 and subsequently transfected into BHK-21 cells generated infectious virus. The plaque morphology, replication kinetics and antigenic profile of clone-derived virus (CDV-1-51) was similar to the parental virus in vitro. Furthermore, the virulence properties of CDV-1-51 and MVE-1-51 (LD(50) values and mortality profiles) were found to be identical in vivo in the mouse model. Through site-directed mutagenesis, the infectious clone should serve as a valuable tool for investigating the molecular determinants of virulence in MVE virus.
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Gil-Duran, S; Arola, D; Ossa, E A
2016-03-01
This paper presents an experimental study of the composition, microstructure and mechanical behavior of scales from the Megalops Atlanticus (Atlantic tarpon). The microstructure and composition were evaluated by Scanning Electron Microscopy (SEM) and RAMAN spectroscopy, respectively. The mechanical properties were evaluated in uniaxial tension as a function of position along the length of the fish (head, mid-length and tail). Results showed that the scales are composed of collagen and hydroxyapatite, and these constituents are distributed within three well-defined layers from the bottom to the top of the scale. The proportion of these layers with respect to the total scale thickness varies radially. The collagen fibers are arranged in plies with different orientations and with preferred orientation in the longitudinal direction of the fish. Results from the tensile tests showed that scales from Megalops Atlanticus exhibit variations in the elastic modulus as a function of body position. Additional testing performed with and without the highly mineralized top layers of the scale revealed that the mechanical behavior is anisotropic and that the highest strength was exhibited along the fish length. Furthermore, removing the top mineralized layers resulted in an increase in the tensile strength of the scale. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Wu, W J; Yan, L; Xie, H; Xu, C L; Wang, K; Jin, S Y
2017-01-01
One new species from Qinghai Province, China, Labronemella major n. sp., is described. The new species is characterized by a body length of 3.03-3.34 mm; lip region wide, offset by a distinct depression, disc-like with six separated inner liplets; amphid fovea funnel-shaped, distinctly bulged on body surface in scanning electron micrographs; odontostyle long (35-39 μm) with distinct lumen, aperture about 39-47% of its length; odontophore rod-like and long; guiding ring double; pharyngeal basal expansion about half of the total neck length; uterus relatively long and tripartite; vulva transverse and sclerotized; spicules 81-90 μm long; ventromedial supplements 19-23; tail short, rounded to conoid. It can be differentiated from all other species of the genus by its relatively longer body, odontostyle and spicules, and wider lip region. Due to the lip region being offset by a deep constriction, and the long (three or more times the body diameter at mid-body) tripartite uterus, the new species is close to Labronemella czernowitzensis (Micoletzky, 1922) Andrássy, 2002 and Labronemella labiata Andrássy, 1985. An improved key to the genus including the new species is provided.
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Comparative morphology among northern populations of breeding Cooper's Hawks
Rosenfield, Robert N.; Rosenfield, Laura J.; Bielefeldt, John; Murphy, Robert K.; Stewart, Andrew C.; Stout, William E.; Driscoll, Timothy G.; Bozek, Michael A.
2010-01-01
Few studies at a broad geographical scale have characterized intraspecific variation in morphology of woodland hawks in the genus Accipiter. From 1999 to 2007 we investigated morphological variation in large samples of live Cooper's Hawks (A. cooperii) nesting in four study areas: coniferous woodland around Victoria, British Columbia, Canada, isolated deciduous woodlands in short-grass prairies of northwestern North Dakota, towns and rural deciduous woodlands along the border of North Dakota and Minnesota, and urban and rural mixed deciduous and coniferous landscapes of Wisconsin. These sites span 2660 km across the northern part of the species' breeding range. We measured body mass (i.e., size), wing chord, tail length, tarsus diameter, hallux length, and culmen length of breeding adults, finding significant and clinal variation in body mass (or size). The smallest and most similar-sized birds occurred in British Columbia and western North Dakota, larger birds along the border between North Dakota and Minnesota, and the largest birds in Wisconsin. Several other characters varied significantly when mass was used as a covariate. Variation by study site in mean indices of sexual size dimorphism was negligible and not significant. We speculate that the morphological differences we found, in part, are the result of geographic isolation, where diets, migratory behavior, and structural characteristics of nesting habitats vary across landscape types.
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Saeng-Chuto, Kepalee; Stott, Christopher James; Wegner, Matthew; Kaewprommal, Pavita; Piriyapongsa, Jittima; Nilubol, Dachrit
2018-06-08
Senecavirus A (SVA) is a novel picornavirus that causes porcine idiopathic vesicular disease characterized by lameness, coronary band hyperemia, and vesicles on the snout and coronary bands. An increase in the detection rate of SVA in several countries suggests that the disease has become a widespread problem. Herein, we report the detection of SVA in Thailand and the characterization of full-length genomic sequences of six Thai SVA isolates. Phylogenetic, genetic, recombination, and evolutionary analyses were performed. The full-length genome, excluding the poly (A) tail of the Thai SVA isolates, was 7282 nucleotides long, with the genomic organization resembling other previously reported SVA isolates. Phylogenetic and genetic analyses based on full-length genome demonstrated that the Thai SVA isolates were grouped in a novel cluster, separated from SVA isolates from other countries. Although the Thai SVA isolates were closely related to 11-55910-3, the first SVA isolate from Canada, with 97.9-98.2%, but they are different. Evolutionary and recombinant analyses suggested that the Thai SVA isolates shared a common ancestor with the 11-55910-3 isolate. The positive selection in the VP4 and 3D genes suggests that the virus was not externally introduced, but rather continuously evolved in the population prior to the first detection. Addition, the presence of SVA could have been ignored due to the presence of other pathogens causing similar clinical diseases. This study warrants further investigations into molecular epidemiology and genetic evolution of the SVA in Thailand. Copyright © 2017. Published by Elsevier B.V.
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Lavagnino, Michael; Bedi, Asheesh; Walsh, Christopher P; Sibilsky Enselman, Elizabeth R; Sheibani-Rad, Shahin; Arnoczky, Steven P
2014-06-01
Tendons are viscoelastic tissues that deform (elongate) in response to cyclic loading. However, the ability of a tendon to recover this elongation is unknown. Tendon length significantly increases after in vivo or in vitro cyclic loading, and the ability to return to its original length through a cell-mediated contraction mechanism is an age-dependent phenomenon. Controlled laboratory study. In vitro, rat tail tendon fascicles (RTTfs) from Sprague-Dawley rats of 3 age groups (1, 3, and 12 months) underwent 2% cyclic strain at 0.17 Hz for 2 hours, and the percentages of elongation were determined. After loading, the RTTfs were suspended for 3 days under tissue culture conditions and photographed daily to determine the amount of length contraction. In vivo, healthy male participants (n = 29; age, 19-49 years) had lateral, single-legged weightbearing radiographs taken of the knee at 60° of flexion immediately before, immediately after, and 24 hours after completing eccentric quadriceps loading exercises on the dominant leg to fatigue. Measurements of patellar tendon length were taken from the radiographs, and the percentages of tendon elongation and subsequent contraction were calculated. In vitro, cyclic loading increased the length of all RTTfs, with specimens from younger (1 and 3 months) rats demonstrating significantly greater elongation than those from older (12 months) rats (P = .009). The RTTfs contracted to their original length significantly faster (P < .001) and in an age-dependent fashion, with younger animals contracting faster. In vivo, repetitive eccentric loading exercises significantly increased patellar tendon length (P < .001). Patellar tendon length decreased 24 hours after exercises (P < .001) but did not recover completely (P < .001). There was a weak but significant (R (2) = 0.203, P = .014) linear correlation between the amount of tendon contraction and age, with younger participants (<30 years) demonstrating significantly more contraction (P = .014) at 24 hours than older participants (>30 years). Cyclic tendon loading results in a significant increase in tendon elongation under both in vitro and in vivo conditions. Tendons in both conditions demonstrated an incomplete return to their original length after 24 hours, and the extent of this return was age dependent. The age- and time-dependent contraction of tendons, elongated after repetitive loading, could result in transient alterations in the mechanobiological environment of tendon cells. This, in turn, could induce the onset of catabolic changes associated with the pathogenesis of tendinopathy. These results suggest the importance of allowing time for contraction between bouts of repetitive exercise and may explain why age is a predisposing factor in tendinopathy. © 2014 The Author(s).
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Effect of Fluorocarbon and Hydrocarbon Chain Lengths in Hybrid Surfactants for Supercritical CO2.
Sagisaka, Masanobu; Ono, Shinji; James, Craig; Yoshizawa, Atsushi; Mohamed, Azmi; Guittard, Frédéric; Rogers, Sarah E; Heenan, Richard K; Yan, Ci; Eastoe, Julian
2015-07-14
Hybrid surfactants containing both fluorocarbon (FC) and hydrocarbon (HC) chains have recently been shown to solubilize water and form elongated reversed micelles in supercritical CO2. To clarify the most effective FC and HC chain lengths, the aggregation behavior and interfacial properties of hybrid surfactants FCm-HCn (FC length m/HC length n = 4/2, 4/4, 6/2, 6/4, 6/5, 6/6, and 6/8) were examined in W/CO2 mixtures as functions of pressure, temperature, and water-to-surfactant molar ratio (W0). The solubilizing power of hybrid surfactants for W/CO2 microemulsions was strongly affected by not only the FC length but also by that of the HC. Although the surfactants having short FC and/or HC tails (namely, m/n = 4/2, 4/4, and 6/2) did not dissolve in supercritical CO2 (even at ∼17 mM, ≤400 bar, temperature ≤ 75 °C, and W0 = 0-40), the other hybrid surfactants were able to yield transparent single-phase W/CO2 mixtures identified as microemulsions. The solubilizing power of FC6-HCm surfactants reached a maximum (W0 ∼ 80 at 45 °C and 350 bar) with a hydrocarbon length, m, of 4. The W0 value of 80 is the highest for a HC-FC hybrid surfactant, matching the highest value reported for a FC surfactant which contained more FC groups. High-pressure small-angle neutron scattering measurements from FCm-HCn/D2O/CO2 microemulsions were consistent with growth of the microemulsion droplets with increasing W0. In addition, not only spherical reversed micelles but also nonspherical assemblies (rodlike or ellipsoidal) were found for the systems with FC6-HCn (n = 4-6). At fixed surfactant concentration and W0 (17 mM and W0 = 20), the longest reversed micelles were obtained for FC6-HC6 where a mean aspect ratio of 6.3 was calculated for the aqueous cores.
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Carbonate deposition on tail feathers of ruddy ducks using evaporation ponds
Euliss, N.H.; Jarvis, R.L.; Gilmer, D.S.
1989-01-01
Substantial carbonate deposits were observed on rectrices of Ruddy Ducks (Oxyura jamaicensis) collected during 1982-1984 on evaporation ponds in the San Joaquin Valley, California. Carbonate deposits were composed of about 75% aragonite and 25% calcite, both polymorphous forms of CaCO3. Significantly more carbonate deposits were observed on Ruddy Ducks as length of exposure to agricultural drain water increased, during the 1983-1984 field season when salt concentrations in the ponds were higher, and in certain evaporation-pond systems.
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Huang, Lige; Li, Yuanyuan; Zhao, Man; Chao, Yuanqing; Qiu, Rongliang; Yang, Yanhua; Wang, Shizhong
2018-03-12
To explore the effect of different biochars on Cassia alata L. growth and heavy metal immobilization in multi-metal mine tailings, a 100-day pot experiment was conducted. Three biochars derived from Hibiscus cannabinus core (HB), sewage sludge (SB) and chicken manure (MB), were added to mine tailings at rates of 0.4%, 1% and 3% ( w / w ). The results showed that the root biomass, shoot biomass, plant height and root length were 1.2-2.8, 1.7-3.2, 1-1.5 and 1.6-3.3 times of those in the control group, respectively. Pb, Zn, Cu, Cd and As contents in the shoot decreased by 63.9-89.5%, 46.9-66.0%, 32.7-62.4%, 40.4-76.4% and 54.9-77.5%, respectively. The biochar significantly increased the pH and decreased the mild acid-soluble Pb and Cu concentrations in the mine tailings. Specifically, SB immobilized Pb and Cu better than MB and HB did, although it did not immobilize As, Zn or Cd. Meanwhile, more attention should be paid to the potential As release as the biochar application rate increases. In conclusion, Cassia alata L. coupled with 3% of SB could be an effective measure for restoring multi-metal mine tailings. This study herein provided a promising ecological restoration technique for future practice of heavy metal stabilization in mine tailings.
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NASA Astrophysics Data System (ADS)
Bud, I.; Duma, S.; Gusat, D.; Pasca, I.; Bud, A.
2017-05-01
In northern Romania, there are numerous tailing ponds, resulting from mining activities that present significant environmental risks. Some of them, including Vrănicioara tailing pond, were the subject of technical projects for ecological rehabilitation. Vrănicioara pond is located on the right side of Cavnic Valley, downstream Cavnic town, about 4 kilometers far. It has about 500 m length and is located parallel to the road linking Baia Sprie and Cavnic localities. Chemical and physical stability of the tailing pond before rehabilitation interest the research, analysis and conclusions were published in several scientific meetings. In addition, close to the pond at less than 100 m, an open pit has developed, exploiting andesite by mining blast, increasing the risk of physical stability by continuous exposure to vibration. This activity currently continues, advancing towards the tailing pond body. The critical study addresses the current state of Vrănicioara Tailing Pond, analysis of some rehabilitation works done incorrectly, analysis of chemical stability that was not a priority during rehabilitation. Research intention is heading to water analysis confirming the existence of acid drainage that was not stopped or at least reduced. The scientific approach is based on the Technical Standards for Waste Deposits, in force in Romania, providing the rules to ensure physical and chemical stability.
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Waning, David L.; Schmitt, Anthony P.; Leser, George P.; Lamb, Robert A.
2002-01-01
The efficient release of many enveloped viruses from cells involves the coalescence of viral components at sites of budding on the plasma membrane of infected cells. This coalescence is believed to require interactions between the cytoplasmic tails of surface glycoproteins and the matrix (M) protein. For the paramyxovirus simian virus 5 (SV5), the cytoplasmic tail of the hemagglutinin-neuraminidase (HN) protein has been shown previously to be important for normal virus budding. To investigate a role for the cytoplasmic tail of the fusion (F) protein in virus assembly and budding, we generated a series of F cytoplasmic tail-truncated recombinant viruses. Analysis of these viruses in tissue culture indicated that the cytoplasmic tail of the F protein was dispensable for normal virus replication and budding. To investigate further the requirements for assembly and budding of SV5, we generated two double-mutant recombinant viruses that lack 8 amino acids of the predicted 17-amino-acid HN protein cytoplasmic tail in combination with truncation of either 10 or 18 amino acids from the predicted 20-amino-acid F protein cytoplasmic tail. Both of the double mutant recombinant viruses displayed a replication defect in tissue culture and a budding defect, the extent of which was dependant on the length of the remaining F cytoplasmic tail. Taken together, this work and our earlier data on virus-like particle formation (A. P. Schmitt, G. P. Leser, D. L. Waning, and R. A. Lamb, J. Virol. 76:3953-3964, 2002) suggest a redundant role for the cytoplasmic tails of the HN and F proteins in virus assembly and budding. PMID:12186912
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Lazinski, David W.; Camilli, Andrew
2013-01-01
The amplification of DNA fragments, cloned between user-defined 5′ and 3′ end sequences, is a prerequisite step in the use of many current applications including massively parallel sequencing (MPS). Here we describe an improved method, called homopolymer tail-mediated ligation PCR (HTML-PCR), that requires very little starting template, minimal hands-on effort, is cost-effective, and is suited for use in high-throughput and robotic methodologies. HTML-PCR starts with the addition of homopolymer tails of controlled lengths to the 3′ termini of a double-stranded genomic template. The homopolymer tails enable the annealing-assisted ligation of a hybrid oligonucleotide to the template's recessed 5′ ends. The hybrid oligonucleotide has a user-defined sequence at its 5′ end. This primer, together with a second primer composed of a longer region complementary to the homopolymer tail and fused to a second 5′ user-defined sequence, are used in a PCR reaction to generate the final product. The user-defined sequences can be varied to enable compatibility with a wide variety of downstream applications. We demonstrate our new method by constructing MPS libraries starting from nanogram and sub-nanogram quantities of Vibrio cholerae and Streptococcus pneumoniae genomic DNA. PMID:23311318
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Mosaic CCD method: A new technique for observing dynamics of cometary magnetospheres
NASA Technical Reports Server (NTRS)
Saito, T.; Takeuchi, H.; Kozuba, Y.; Okamura, S.; Konno, I.; Hamabe, M.; Aoki, T.; Minami, S.; Isobe, S.
1992-01-01
On April 29, 1990, the plasma tail of Comet Austin was observed with a CCD camera on the 105-cm Schmidt telescope at the Kiso Observatory of the University of Tokyo. The area of the CCD used in this observation is only about 1 sq cm. When this CCD is used on the 105-cm Schmidt telescope at the Kiso Observatory, the area corresponds to a narrow square view of 12 ft x 12 ft. By comparison with the photograph of Comet Austin taken by Numazawa (personal communication) on the same night, we see that only a small part of the plasma tail can be photographed at one time with the CCD. However, by shifting the view on the CCD after each exposure, we succeeded in imaging the entire length of the cometary magnetosphere of 1.6 x 10(exp 6) km. This new technique is called 'the mosaic CCD method'. In order to study the dynamics of cometary plasma tails, seven frames of the comet from the head to the tail region were twice imaged with the mosaic CCD method and two sets of images were obtained. Six microstructures, including arcade structures, were identified in both the images. Sketches of the plasma tail including microstructures are included.
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Body molt of male long-tailed ducks in the nearshore waters of the north slope, Alaska
Howell, M.D.; Grand, J.B.; Flint, Paul L.
2003-01-01
We examined the timing and intensity of body molt in relation to stage of remige growth for postbreeding adult male Long-tailed Ducks (Clangula hyemalis) off the coast of northern Alaska. During this period, remige and rectrix feathers are molted simultaneously with body feathers during the prebasic molt, which results in a period of increased energetic and nutritional demands. We collected birds from late July through mid-August and recorded intensity of molt in eight regions: head and neck, back and rump, greater coverts, lesser coverts, flank and sides, breast, belly, and tail. Using nonlinear regression, we estimated the peak intensity and variation for each region in relation to ninth primary length. We found little evidence of molt in the head and neck region. The greater and lesser coverts, and back and rump reached peak molt intensities earliest and were followed by tail, breast, and belly. Molt intensity in the flank and side region was highly variable and indicated a more prolonged molting pattern in relation to other regions. While body molt occurs simultaneously with wing molt, we found that molt among regions occurred in a staggered pattern. Long-tailed Ducks may employ this staggered molting pattern to minimize the energetic and nutritional requirements of molt.
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Gely, Stéphane; Lowry, David F; Bernard, Cédric; Jensen, Malene R; Blackledge, Martin; Costanzo, Stéphanie; Bourhis, Jean-Marie; Darbon, Hervé; Daughdrill, Gary; Longhi, Sonia
2010-01-01
In this report, the solution structure of the nucleocapsid-binding domain of the measles virus phosphoprotein (XD, aa 459-507) is described. A dynamic description of the interaction between XD and the disordered C-terminal domain of the nucleocapsid protein, (N(TAIL), aa 401-525), is also presented. XD is an all alpha protein consisting of a three-helix bundle with an up-down-up arrangement of the helices. The solution structure of XD is very similar to the crystal structures of both the free and bound form of XD. One exception is the presence of a highly dynamic loop encompassing XD residues 489-491, which is involved in the embedding of the alpha-helical XD-binding region of N(TAIL). Secondary chemical shift values for full-length N(TAIL) were used to define the precise boundaries of a transient helical segment that coincides with the XD-binding domain, thus shedding light on the pre-recognition state of N(TAIL). Titration experiments with unlabeled XD showed that the transient alpha-helical conformation of N(TAIL) is stabilized upon binding. Lineshape analysis of NMR resonances revealed that residues 483-506 of N(TAIL) are in intermediate exchange with XD, while the 475-482 and 507-525 regions are in fast exchange. The N(TAIL) resonance behavior in the titration experiments is consistent with a complex binding model with more than two states.
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Eto, Ko; Iwama, Tomoyuki; Tajima, Tatsuya; Abe, Shin-ichi
2012-10-01
Frog metamorphosis induced by thyroid hormone (TH) involves not only cell proliferation and differentiation in reconstituted organs such as limbs, but also apoptotic cell death in degenerated organs such as tails. However, the molecular mechanisms directing the TH-dependent cell fate determination remain unclear. We have previously identified from newts an RNA-binding protein (nRBP) acting as the regulator governing survival and death in germ cells during spermatogenesis. To investigate the molecular events leading the tail resorption during metamorphosis, we analyzed the expression, the functional role in apoptosis, and the regulation of xCIRP2, a frog homolog of nRBP, in tails of Xenopus laevis tadpoles. At the prometamorphic stage, xCIRP2 protein is expressed in fibroblast, epidermal, nerve, and muscular cells and localized in their cytoplasm. When spontaneous metamorphosis progressed, the level of xCIRP2 mRNA remained unchanged but the amount of the protein decreased. In organ cultures of tails at the prometamorphic stage, xCIRP2 protein decreased before their lengths shortened during TH-dependent metamorphosis. The inhibition of calpain or proteasome attenuated the TH-induced decrease of xCIRP2 protein in tails, impairing their regression. These results suggest that xCIRP2 protein is downregulated through calpain- and proteasome-mediated proteolysis in response to TH at the onset of metamorphosis, inducing apoptosis in tails and thereby degenerating them. Copyright © 2012 Elsevier Inc. All rights reserved.
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Effect of chain length on binding of fatty acids to Pluronics in microemulsions.
James-Smith, Monica A; Shekhawat, Dushyant; Cheung, Sally; Moudgil, Brij M; Shah, Dinesh O
2008-03-15
We investigated the effect of fatty acid chain length on the binding capacity of drug and fatty acid to Pluronic F127-based microemulsions. This was accomplished by using turbidity experiments. Pluronic-based oil-in-water microemulsions of various compositions were synthesized and titrated to turbidity with concentrated Amitriptyline, an antidepressant drug. Sodium salts of C(8), C(10), or C(12) fatty acid were used in preparation of the microemulsion and the corresponding binding capacities were observed. It has been previously determined that, for microemulsions prepared with sodium caprylate (C(8) fatty acid soap), a maximum of 11 fatty acid molecules bind to the microemulsion per 1 molecule of Pluronic F127 and a maximum of 12 molecules of Amitriptyline bind per molecule of F127. We have found that with increasing the chain length of the fatty acid salt component of the microemulsion, the binding capacity of both the fatty acid and the Amitriptyline to the microemulsion decreases. For sodium salts of C(8), C(10) and C(12) fatty acids, respectively, a maximum of approximately 11, 8.4 and 8.3 molecules of fatty acid molecules bind to 1 Pluronic F127 molecule. We propose that this is due to the decreasing number of free monomers with increasing chain length. As chain length increases, the critical micelle concentration (cmc) decreases, thus leading to fewer monomers. Pluronics are symmetric tri-block copolymers consisting of propylene oxide (PO) and ethylene oxide (EO). The polypropylene oxide block, PPO is sandwiched between two polyethylene oxide (PEO) blocks. The PEO blocks are hydrophilic while PPO is hydrophobic portion in the Pluronic molecule. Due to this structure, we propose that the fatty acid molecules that are in monomeric form most effectively diffuse between the PEO "tails" and bind to the hydrophobic PPO groups.
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Changes in myosin S1 orientation and force induced by a temperature increase.
Griffiths, Peter J; Bagni, Maria A; Colombini, Barbara; Amenitsch, Heinz; Bernstorff, Sigrid; Ashley, Christopher C; Cecchi, Giovanni; Ameritsch, Heinz
2002-04-16
Force generation in myosin-based motile systems is thought to result from an angular displacement of the myosin subfragment 1 (S1) tail domain with respect to the actin filament axis. In muscle, raised temperature increases the force generated by S1, implying a greater change in tail domain angular displacement. We used time-resolved x-ray diffraction to investigate the structural corollary of this force increase by measuring M3 meridional reflection intensity during sinusoidal length oscillations. This technique allows definition of S1 orientation with respect to the myofilament axis. M3 intensity changes were approximately sinusoid at low temperatures but became increasingly distorted as temperature was elevated, with the formation of a double intensity peak at maximum shortening. This increased distortion could be accounted for by assuming a shift in orientation of the tail domain of actin-bound S1 toward the orientation at which M3 intensity is maximal, which is consistent with a tail domain rotation model of force generation in which the tail approaches a more perpendicular projection from the thin filament axis at higher temperatures. In power stroke simulations, the angle between S1 tail mean position during oscillations and the position at maximum intensity decreased by 4.7 degrees, corresponding to a mean tail displacement toward the perpendicular of 0.73 nm for a temperature-induced force increase of 0.28 P(0) from 4 to 22 degrees C. Our findings suggest that at least 62% of crossbridge compliance is associated with the tail domain.
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The effect of colloid osmotic pressure in human spermatozoa exposed to hypoosmotic conditions.
Correa-Pérez, J R; Fernández-Pelegrina, R; Zarmakoupis-Zavos, P N; Zavos, P M
2003-04-01
The use of a protein source such as serum and albumin had been extensively employed as supplements of culture media for handling and culture of gametes and embryos. Protein molecules behave as colloids in solution and contribute to the osmotic pressure of fluids. The interaction of proteins in solution and spermatozoa needs to be assessed in order to determine their possible role in osmoregulation. The aim of this study was to assess possible osmoregulatory mechanisms of protein supplementation against exposure to hypoosmotic conditions by assessing the sperm's response to those environments. A stock hypoosmotic solution (HOS) was prepared by using a mixture of fructose and sodium citrate and adjusted to an osmotic pressure of 150 mOsm l-1. Another stock solution was prepared by diluting a preparation of synthetic serum supplement [SSS; 6% (v/v) total protein] with distilled water to obtain an osmotic pressure of 150 mOsm l-1 (hypoosmotic SSS or H-SSS). Three additional solutions were prepared by mixing the stock HOS and H-SSS solutions in the following proportions (v/v): (i) 75% H-SSS/25% HOS, (ii) 50% H-SSS/50% HOS and (iii) 25% H-SSS/75% HOS. Aliquots of washed spermatozoa from 18 men were diluted 1 : 10 (v/v) with each of the testing solutions and incubated for 60 min. Specimens were assessed on wet mounts for total and specific swelling patterns. Swelling patterns were classified as maximal (>50% tail length swollen) and minimal (<50% tail length swollen) swelling with or without associated sperm motility. The major finding of this study was that increasing the concentration of protein supplementation resulted in a decrease in the proportion of maximal sperm tail swelling patterns and an increase in the proportion of minimal tail swelling patterns. A proportion of spermatozoa which exhibited minimal swelling patterns were still motile in all solutions tested, and the percentage of those spermatozoa increased as the protein supplementation was also increased in the testing solutions. Incorporation of protein supplementation as described in this study delays the effect of sperm swelling in hypoosmotic conditions.
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de-Bashan, Luz E.; Hernandez, Juan-Pablo; Bashan, Yoav; Maier, Raina
2014-01-01
Three plant growth-promoting bacteria (PGPB; Bacillus pumilus ES4, B. pumilus RIZO1, and Azospirillum brasilense Cd) were tested for their ability to enhance plant growth and development of the native Sonoran Desert shrub quailbush (Atriplex lentiformis) and for their effect on the native bacterial community in moderately acidic, high-metal content (AHMT) and in neutral, low metal content natural tailings (NLMT) in controlled greenhouse experiments. Inoculation of quailbush with all three PGPB significantly enhanced plant growth parameters, such as germination, root length, dry weight of shoots and roots, and root/shoot ratio in both types of tailings. The effect of inoculation on the indigenous bacterial community by the most successful PGPB Bacillus pumilus ES4 was evaluated by denaturating gradient gel electrophoresis (PCR-DGGE) fingerprinting and root colonization was followed by specific fluorescent in situ hybridization (FISH). Inoculation with this strain significantly changed the bacterial community over a period of 60 days. FISH analysis showed that the preferred site of colonization was the root tips and root elongation area. This study shows that inoculation of native perennial plants with PGPB can be used for developing technologies for phytostabilizing mine tailings. PMID:25009362
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Acoustic and aerodynamic study of a pusher-propeller aircraft model
NASA Astrophysics Data System (ADS)
Soderman, Paul T.; Horne, W. Clifton
1990-09-01
An aerodynamic and acoustic study was made of a pusher-propeller aircraft model in the NASA-Ames 7 x 10 ft Wind Tunnel. The test section was changed to operate as an open jet. The 591 mm diameter unswept propeller was operated alone and in the wake of three empennages: an I tail, Y tail, and a V tail. The radiated noise and detailed wake properties were measured. Results indicate that the unsteady blade loading caused by the blade interactions with the wake mean velocity distribution had a strong effect on the harmonics of blade passage noise. The blade passage harmonics above the first were substantially increased in all horizontal directions by the empennage/propeller interaction. Directivity in the plane of the propeller was maximum perpendicular to the blade surface. Increasing the tail loading caused the propeller harmonics to increase 3 to 5 dB for an empennage/propeller spacing of 0.38 mean empennage chords. The interaction noise became weak as empennage propeller spacing was increased beyond 1.0 mean empennage chord lengths. Unlike the mean wake deficit, the wake turbulence had only a small effect on the propeller noise, that effect being a small increase in the broadband noise.
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Acoustic and aerodynamic study of a pusher-propeller aircraft model
NASA Technical Reports Server (NTRS)
Soderman, Paul T.; Horne, W. Clifton
1990-01-01
An aerodynamic and acoustic study was made of a pusher-propeller aircraft model in the NASA-Ames 7 x 10 ft Wind Tunnel. The test section was changed to operate as an open jet. The 591 mm diameter unswept propeller was operated alone and in the wake of three empennages: an I tail, Y tail, and a V tail. The radiated noise and detailed wake properties were measured. Results indicate that the unsteady blade loading caused by the blade interactions with the wake mean velocity distribution had a strong effect on the harmonics of blade passage noise. The blade passage harmonics above the first were substantially increased in all horizontal directions by the empennage/propeller interaction. Directivity in the plane of the propeller was maximum perpendicular to the blade surface. Increasing the tail loading caused the propeller harmonics to increase 3 to 5 dB for an empennage/propeller spacing of 0.38 mean empennage chords. The interaction noise became weak as empennage propeller spacing was increased beyond 1.0 mean empennage chord lengths. Unlike the mean wake deficit, the wake turbulence had only a small effect on the propeller noise, that effect being a small increase in the broadband noise.
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Jin, Yiguang; Chen, Shufeng; Xin, Rui; Zhou, Yisheng
2008-07-15
Isoniazid (INH, isonicotinic acid hydrazide) is one of the most commonly used anti-tubercular drugs. However, resistance of Mycobacterium tuberculosis strains to anti-mycobacterial agents including INH is an increasing problem worldwide. Development of new anti-mycobacterial agents thus has attracted attention. Five lipid derivatives of INH were prepared in this study. They formed monolayers at the air/water interface, and some nanostructures with different morphologies were obtained through molecular self-assembly in water. The derivatives included one fatty acyl derivative containing a 12-C hydrocarbon-long chain (1), three fatty alcohol derivatives with a succinyl as spacer and an 8, 12 or 16-C hydrocarbon-long chain (2, 3 and 4), and one tetrahydro-2H-1,3,5-thiadiazine-2-thione (THTT) derivative containing a 12-C hydrocarbon-long chain (5). The surface pressure-area isotherms depended on the volume and configuration of heads and the length of tails of derivatives. Compound 2 had a relatively large head and a short tail, easily standing uprightly at the interface. Under a certain surface pressure, the linear polar head groups of 3 could be partly squeezed out and insert into subphase because the length of heads were comparable to the one of tails. The very long tails of 4 always maintained above the interface and led to a high collapse pressure. Compound 5 possessed an extended and large head consisting of the THTT and INH groups so that the relatively short tails tilted at the interface and difficultly contact with each other. The THTT rings might be partly squeezed out and enter into air under a certain surface pressure. The self-assembly behaviours of derivatives in water depended on the molecular configuration and agreed with the corresponding monolayer behaviours. The flexible and medium-long tails (1 and 3) led to the derivatives to form nanoscale vesicles, though the short or very long tails did not (2 and 4). Interestingly, intermolecular hydrogen bonding could occur between the molecules of 5, and improve the derivative forming helical nanofibres other than vesicles. The molecular self-assembly of INH's lipid derivatives was explored in details in this study. The formation mechanisms of self-assembled nanostructures were analyzed. Various types of self-assembled nanostructures were obtained and the formation mechanisms were analyzed. The relationship between the self-assembly and the molecular configuration of amphiphilic derivatives was also revealed. The lipid derivatives of INH show promising anti-Mycobacterium action because the amphiphilic prodrugs allow for better penetration of the bacterial cells. The self-assembled nanostructures may likely be the potential self-assembled drug delivery systems for tuberculosis therapy.
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Sun, Fengcheng; Henry, Neil; Yu, Qing
2017-06-01
Although fig trees are a popular ornamental fruit tree in subtropical regions, some hardy species, such as Ficus carica , have been grown in the west coast of British Columbia and southern Ontario in Canada. The fig cyst nematode, Heterodera fici Kirjanova, is a pest on fig plants, and the heavy infestation can cause retarded growth and yellowing of leaves (Maqbool et al., 1987). In the spring of 2016, a sample of rhizosphere from a potted fig ( F. carica ) seedling was submitted to the Nematology Laboratory, Canadian Food Inspection Agency. The sample was collected from a nursery in Niagara-on-the-Lake, Ontario, Canada, during an inspection to support export certification. The fig trees in the nursery had been grown in the outside fields during the growing seasons and potted and moved to indoor during the winters for last 3 years. The sample was subjected to a nematode extraction process, including decanting and sieving and misting, and lemon-shaped cysts and second-stage juveniles of Heterodera sp. were recovered from the sample examined. The morphological and molecular analyses of the cysts, vulval cone, and second-stage juveniles from both the roots and the crushed cysts identified the species as Heterodera fici Kirjanova. The cysts were characterized by their dark brown color and lemon shape, as well as distinct necks and vulval cones. The vulval cones were observed having an ambifenestrate fenestra (Fig. 1AFig. 1Photomicrographs of Heterodera fici on fig tree from Ontario, Canada. A, B. Cyst vulval cones with the ambifenestrate fenestra in A) and well-developed underbridge and bullae in B). C-E. The second-stage juveniles from a crushed cyst with the whole body in C), the anterior region in D) and the posterior region in E).), dome-shaped bullae scattered around the underbridge plane (Fig. 1B), well-developed underbridge (Fig. 1B), and coarse zig-zag ridges surrounding the fenestra on the surface. The cyst measurements ( n = 3) were length 608.7 ± 91.6 (506-682) µm, width = 395.3 ± 40.9 (366-442) µm, and length/width ratio = 1.3 ± 0.2 (1.3-1.7) µm. The morphometric characters of the vulval cone were fenestral length = 57.3 ± 2.9 (54-59) µm, fenestral width = 35.3 ± 4 (33-40) µm, and vulval slit = 50.7 ± 1.2 (50-52) µm. Second-stage juveniles tapering posteriorly (Fig. 1C). Stylet well developed, basal knobs rounded, directed slightly anteriorly (Fig. 1D). Tail tapering, with hyaline terminal about half of tail length (Fig. 1E). Second-stage juveniles ( n = 16) showed the following morphometric characters: body length = 440.9 ± 20 (408-470) µm, a = 20.3 ± 2.3 (16.9-24), b = 2.7 ± 0.3 (2.3-3.3), c = 8.1 ± 0.6 (7.3-9.3), c' = 3.8 ± 0.3 (3.1-4.3), stylet length = 23.2 ± 0.4 (23-24) µm, anterior end to median bulb = 71.8 ± 4.5 (65-79) µm; maximum body width = 21.9 ± 2 (17-25) µm; body width at anus = 14.4 ± 1.5 (12-17) µm, tail length = 54.6 ± 2.9 (50-60) µm, and hyaline part of tail = 23.7 ± 2.9 (19-28) µm. These observations conform to the published descriptions of Heterodera fici Kirjanova (Kirjanova, 1954; Golden et al., 1988). The slides of the cyst vulval cone and juveniles were deposited in the Canadian National collection of Insects, Arachnids, and Nematodes (Accession no. 14851 to 14853 for the second stage juveniles and 14854-14855 for the cyst cones). For molecular analysis, DNA was extracted from individual juvenile ( n = 4) from different cysts. A 1,151-bp fragment of ribosomal DNA containing ITS1-5.8S-ITS2 region was amplified and sequenced using primers 18S (5'-TTGATTACGTCCCTGCCCTTT-3') and 26S (5'- TTTCACTCGCCGTTACTAAGG-3') (Vrain et al., 1992). The sequence was deposited into the GenBank database (Accession no. KY635986 and KY635987) and was compared with published sequences by means of BLAST search in the database (November 2016). The comparison revealed 99.0% to 100% similarity to the sequences of the same genomic region of H. fici from Iran (AF498385) and Georgia (AF274409). Subbotin et al. (2010) summarized the known occurrence of the fig cyst nematode from Belarus, Belgium, Estonia, France, Germany, Greece, Hungary, Italy, The Netherlands, Norway, Poland, Portugal, Russia, Spain, Yugoslavia, China, Georgia, Iran, Turkey, Uzbekistan, Australia, New Zealand, United States (California, Florida, Louisiana, Maryland, and Virginia), Brazil, Algeria, and South Africa. It is an exotic pest to Canada. To our knowledge, this is the first evidence of the occurrence of H. fici in Canada.
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Habchi, Johnny; Blangy, Stéphanie; Mamelli, Laurent; Jensen, Malene Ringkjøbing; Blackledge, Martin; Darbon, Hervé; Oglesbee, Michael; Shu, Yaoling; Longhi, Sonia
2011-04-15
The Henipavirus genome is encapsidated by the nucleoprotein (N) within a helical nucleocapsid that recruits the polymerase complex via the phosphoprotein (P). In a previous study, we reported that in henipaviruses, the N-terminal domain of the phosphoprotein and the C-terminal domain of the nucleoprotein (N(TAIL)) are both intrinsically disordered. Here we show that Henipavirus N(TAIL) domains are also disordered in the context of full-length nucleoproteins. We also report the cloning, purification, and characterization of the C-terminal X domains (P(XD)) of Henipavirus phosphoproteins. Using isothermal titration calorimetry, we show that N(TAIL) and P(XD) form a 1:1 stoichiometric complex that is stable under NaCl concentrations as high as 1 M and has a K(D) in the μM range. Using far-UV circular dichroism and nuclear magnetic resonance, we show that P(XD) triggers an increase in the α-helical content of N(TAIL). Using fluorescence spectroscopy, we show that P(XD) has no impact on the chemical environment of a Trp residue introduced at position 527 of the Henipavirus N(TAIL) domain, thus arguing for the lack of stable contacts between the C termini of N(TAIL) and P(XD). Finally, we present a tentative structural model of the N(TAIL)-P(XD) interaction in which a short, order-prone region of N(TAIL) (α-MoRE; amino acids 473-493) adopts an α-helical conformation and is embedded between helices α2 and α3 of P(XD), leading to a relatively small interface dominated by hydrophobic contacts. The present results provide the first detailed experimental characterization of the N-P interaction in henipaviruses and designate the N(TAIL)-P(XD) interaction as a valuable target for rational antiviral approaches.
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Konani, Ehsan; Panahandeh, Yousef; Pourjam, Ebrahim; Álvarez-Ortega, Sergio; Pedram, Majid
2018-04-23
Two rare species of the family Tylenchidae are described and illustrated based on morphological and morphometric characters. Scanning electron microscope (SEM) studies provided details of anterior end structures, helpful in generic identification of the studied populations. Discotylenchus biannulatus n. sp. is characterized by its dorso-ventrally flattened smooth cephalic region having two proximal annuli and a rectangular perioral disc, short longitudinal amphidial slits, lateral field with four incisures, stylet 9-10 μm long, with the conus shorter than half the total stylet length and with posteriorly directed knobs, well-developed median bulb, mono-prodelphic reproductive system with rounded empty spermatheca and short postvulval uterine sac (PUS), and filiform tail with pointed end. It is compared with other species of Discotylenchus having four lines in the lateral field. The Iranian population of Labrys chinensis is characterized by its long and slender (a = 45.2-57.2) body, smooth rounded cephalic region and an offset disc-like apical labial plate, short longitudinal lateral amphidial slits, lateral field with two incisures, moderately developed stylet with the conus less than half the total length and posteriorly directed knobs, median bulb fusiform with distinct but weak valve, gradually joining the isthmus, vulva at 57.2-59.1% with small flaps, elongate conoid tail, uniformly and slightly narrowing toward end with broadly rounded terminus and rare males. The minor morphological differences of the recovered population with the type population are discussed.
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DNA Damage Analysis in Children with Non-syndromic Developmental Delay by Comet Assay.
Susai, Surraj; Chand, Parkash; Ballambattu, Vishnu Bhat; Hanumanthappa, Nandeesha; Veeramani, Raveendranath
2016-05-01
Majority of the developmental delays in children are non-syndromic and they are believed to have an underlying DNA damage, though not well substantiated. Hence the present study was carried out to find out if there is any increased DNA damage in children with non-syndromic developmental delay by using the comet assay. The present case-control study was undertaken to assess the level of DNA damage in children with non syndromic developmental delay and compare the same with that of age and sex matched controls using submarine gel electrophoresis (Comet Assay). The blood from clinically diagnosed children with non syndromic developmental delay and controls were subjected for alkaline version of comet assay - Single cell gel electrophoresis using lymphocytes isolated from the peripheral blood. The comets were observed under a bright field microscope; photocaptured and scored using the Image J image quantification software. Comet parameters were compared between the cases and controls and statistical analysis and interpretation of results was done using the statistical software SPSS version 20. The mean comet tail length in cases and control was 20.77+7.659μm and 08.97+4.398μm respectively which was statistically significant (p<0.001). Other comet parameters like total comet length and % DNA in tail also showed a statistically significant difference (p < 0.001) between cases and controls. The current investigation unraveled increased levels of DNA damage in children with non syndromic developmental delay when compared to the controls.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Li, Yang; National Institute of Biological Sciences, Beijing 102206; Xiong, Wei
Although a deficiency in CRY1 or CRY2 correlates with a shorter or longer circadian period, the regulation of CRY proteins in the circadian period has not been well studied. In this study, we found that both CRY1 and CRY2 were able to rescue oscillation in CRY null cells and that they displayed different periods. Furthermore, we demonstrated that protein nuclear import rates, not protein stability, regulate the period-length at the cellular level. Co-transfection of CRY1 and CRY2 in various ratios in the same cells gives rise to the predicted period length in a dose-dependent manner. Given the distinct characteristics ofmore » the C-terminal tails of the CRY1 and CRY2 proteins, our study addresses a long-standing hypothesis that the ratio of these two CRY molecules affects the clock period. - Highlights: • Rhythmic CRY2, like CRY1, in the correct CRY1 phase is sufficient to rescue clock oscillation in CRY null cells. • The short-period mammalian CRY2 protein is more stable than the CRY1 protein. • The N-terminal polypeptide of CRY2 contributes to its stability and Per2 repression, but it does not affect the period. • The C-terminal tails of CRYs regulate their protein stability and nuclear import, but the import rate governs the period. • The ratio, rather than the absolute amounts of CRY1 and CRY2 proteins, determines the period in mammalian cells.« less
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Moravec, František; Justine, Jean-Lou
2015-11-01
Based on light and scanning electron microscopical studies, two new species of Hysterothylacium Ward & Magath, 1917 (Nematoda: Anisakidae) are described from the digestive tract of perciform fishes off New Caledonia: H. alatum n. sp. from Plectropomus laevis (Lacépède) (Serranidae) and H. sphyraenae n. sp. from Sphyraena qenie Klunzinger (Sphyraenidae). The former species (H. alatum) is mainly characterised by its large body (male 42.05 mm, gravid females 51.18-87.38 mm long), the shape of the dorsal lip, conspicuously broad cervical alae, a short caecum and a long ventricular appendix, the length of the spicules (925 µm), the number (25 pairs) and distribution of the genital papillae and the tail tip bearing numerous minute cuticular protuberances. The other species (H. sphyraenae) is mainly characterised by the presence of narrow lateral alae, a short caecum and a long ventricular appendix, the length (762-830 µm) and shape of the spicules, the number (37-38 pairs) and arrangement of the genital papillae, and by the tail tip which lacks any distinct cuticular projections visible under the light microscope. In addition, and unidentifiable at the species level, conspicuously large (45.71-66.10 mm long) larvae of Contracaecum Railliet & Henry, 1912, were found in the body cavity of P. laevis, which serves as a paratenic host for this parasite.
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Mantha, Sriteja; McDaniel, Jesse G; Perroni, Dominic V; Mahanthappa, Mahesh K; Yethiraj, Arun
2017-01-26
Gemini surfactants comprise two single-tailed surfactants connected by a linker at or near the hydrophilic headgroup. They display a variety of water-concentration-dependent lyotropic liquid crystal morphologies that are sensitive to surfactant molecular structure and the nature of the headgroups and counterions. Recently, an interesting dependence of the aqueous-phase behavior on the length of the linker has been discovered; odd-numbered linker length surfactants exhibit characteristically different phase diagrams than even-numbered linker surfactants. In this work, we investigate this "odd/even effect" using computer simulations, focusing on experimentally studied gemini dicarboxylates with Na + counterions, seven nonterminal carbon atoms in the tails, and either three, four, five, or six carbon atoms in the linker (denoted Na-73, Na-74, Na-75, and Na-76, respectively). We find that the relative electrostatic repulsion between headgroups in the different morphologies is correlated with the qualitative features of the experimental phase diagrams, predicting destabilization of hexagonal phases as the cylinders pack close together at low water content. Significant differences in the relative headgroup orientations of Na-74 and Na-76 compared to those of Na-73 and Na-75 surfactants lead to differences in linker-linker packing and long-range headgroup-headgroup electrostatic repulsion, which affects the delicate electrostatic balance between the hexagonal and gyroid phases. Much of the fundamental insight presented in this work is enabled by the ability to computationally construct and analyze metastable phases that are not observable in experiments.
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Building a flagellum in biological outer space.
Evans, Lewis D B; Hughes, Colin; Fraser, Gillian M
2014-02-01
Flagella, the rotary propellers on the surface of bacteria, present a paradigm for how cells build and operate complex molecular 'nanomachines'. Flagella grow at a constant rate to extend several times the length of the cell, and this is achieved by thousands of secreted structural subunits transiting through a central channel in the lengthening flagellum to incorporate into the nascent structure at the distant extending tip. A great mystery has been how flagella can assemble far outside the cell where there is no conventional energy supply to fuel their growth. Recent work published by Evans et al. [ Nature (2013) 504: 287-290], has gone some way towards solving this puzzle, presenting a simple and elegant transit mechanism in which growth is powered by the subunits them selves as they link head-to-tail in a chain that is pulled through the length of the growing structure to the tip. This new mechanism answers an old question and may have resonance in other assembly processes.
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Teixeira, R D; Scheltinga, D M; Trauth, S E; Colli, G R; Báo, S N
2002-06-01
The ultrastructure of the spermatozoa of Cnemidophorus gularis gularis, Cnemidophorus ocellifer, and Kentropyx altamazonica is described for the first time. Mature spermatozoa of Cnemidophorus spp. and K. altamazonica differ in the occurrence of a perforatorial base plate, the enlargement of axonemal fibers 3 and 8, and shape of mitochondria. The comparisons of the ultrastructure sperm of Cnemidophorus spp. and K. altamazonica with Ameiva ameiva [J. Morphol. (2002) in press] suggest that Ameiva and Cnemidophorus are more similar to each other than either is to Kentropyx. Statistical analyses reveal that sperm of all three species studied are significantly different in the following dimensions: head, acrosome, distal centriole length, and nuclear shoulders width. There was no variable statistically different between the Cnemidophorus spp. only. The length of the tail, midpiece, entire sperm, and nuclear rostrum are significantly different between K. altamazonica and Cnemidophorus spp. Our results indicate that sperm ultrastructure presents intra and intergeneric variability.
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Identifying sex and age of apapane and iiwi on Hawaii
Fancy, S.G.; Pratt, T.K.; Lindsey, G.D.; Harada, C.K.; Parent, A.H.; Jacobi, J.D.
1993-01-01
Methods to determine the sex and age of Apapane (Himatione sanguinea) and Iiwi (Vestiaria coccinea) were developed on the basis of 189 museum specimens and 91 live birds captured in mist nets on the Island of Hawaii (USA). Both species retain all juvenal primaries and some juvenal secondaries and body feathers after the first prebasic molt and attain full adult plumage after the second prebasic molt. Apapane in their first basic plumage retain some buff-edged juvenal secondaries (particularly secondaries five and six) and sometimes retain a few gray-brown feathers on the head. The first basic plumage of Iiwi is characterized by secondaries 6-9 being longer and darker than secondaries 1-4 and the presence of a few yellowish juvenal body feathers with black spots at the tips. Adult male Apapane and Iiwi have longer wing, tail, exposed culmen, culmen and tarso-metatarsus lengths than females. Linear discriminant functions are presented to sex adult Apapane and Iiwi from lengths of their wing chord and exposed culmen.
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MagnetoSperm: A microrobot that navigates using weak magnetic fields
NASA Astrophysics Data System (ADS)
Khalil, Islam S. M.; Dijkslag, Herman C.; Abelmann, Leon; Misra, Sarthak
2014-06-01
In this work, a propulsion system similar in motion to a sperm-cell is investigated. This system consists of a structure resembling a sperm-cell with a magnetic head and a flexible tail of 42 μm and 280 μm in length, respectively. The thickness, length, and width of this structure are 5.2 μm, 322 μm, and 42 μm, respectively. The magnetic head includes a 200 nm-thick cobalt-nickel layer. The cobalt-nickel layer provides a dipole moment and allows the flexible structure to align along oscillating weak (less than 5 mT) magnetic field lines, and hence generates a propulsion thrust force that overcomes the drag force. The frequency response of this system shows that the propulsion mechanism allows for swimming at an average speed of 158 ± 32 μm/s at alternating weak magnetic field of 45 Hz. In addition, we experimentally demonstrate controlled steering of the flexible structure towards reference positions.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Williams, J.J.; Wofford, H.W.
1996-10-01
The increase in ultraviolet light intensity levels due to ozone depletion recently has been linked to the decline in amphibian population. In this experiment, eggs and larvae of Rana pipiens were subjected to differing amounts of ultraviolet radiation to determine the effects of ultraviolet light on the development of amphibian tadpoles. The total length, length of body without tail, and maximum width of each specimen was recorded for a month of the tadpoles` development, including several measurements after the ultraviolet exposures were concluded. It was found that ultraviolet exposure significantly reduced the size of the organisms in comparison with themore » control group in all three measured areas. Ultraviolet radiation altered the health and appearance of the exposed organisms and was lethal at large amounts. This experiment showed that ultraviolet radiation could cause many problems in developing amphibians. By slowing their development and physically weakening predation, thus contributing to a decline in overall population levels.« less
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The high-throughput synthesis and phase characterisation of amphiphiles: a sweet case study.
Feast, George C; Hutt, Oliver E; Mulet, Xavier; Conn, Charlotte E; Drummond, Calum J; Savage, G Paul
2014-03-03
A new method for the discovery of amphiphiles by using high-throughput (HT) methods to synthesise and characterise a library of galactose- and glucose-containing amphiphilic compounds is presented. The copper-catalysed azide–alkyne cycloaddition (CuAAC) “click” reaction between azide-tethered simple sugars and alkyne-substituted hydrophobic tails was employed to synthesise a library of compounds with systematic variations in chain length and unsaturation in a 24-vial array format. The liquid–crystalline phase behaviour was characterised in a HT manner by using synchrotron small-angle X-ray scattering (SSAXS). The observed structural variation with respect to chain parameters, including chain length and degree of unsaturation, is discussed, as well as hydration effects and degree of hydrogen bonding between head groups. The validity of our HT screening approach was verified by resynthesising a short-chain glucose amphiphile. A separate phase analysis of this compound confirmed the presence of numerous lyotropic liquid–crystalline phases.
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2005-01-01
Abstract The study objectives were to provide a province-wide description of stall dimensions and the aspects of cattle welfare linked to stall design in the tie-stall industry. Data on stall design; stall dimensions; and the prevalence of lameness, injury, and hind limb and udder cleanliness in lactating dairy cattle were collected from a sample of 317 tie-stall farms across Ontario. The majority of the study farms (90%) had stalls with dimensions (length, width, tie-chain length, and tie rail height) that were less than the current recommendations. This may explain, in part, the prevalence of lameness measured as the prevalence of back arch (3.2%) and severe hind claw rotation (23%), hock lesions (44%), neck lesions (3.8%), broken tails (3%), dirty hind limbs (23%), and dirty udders (4.6%). Veterinarians and producers may use this information to compare farms with the industry averages and target areas in need of improvement. PMID:16454382
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Goto, Ryosuke; Kumakura, Hiroo
2013-05-01
In this study we compared the power arm lengths and mechanical advantages attributed to 12 lower leg muscles across three prosimian species. The origins and insertions of the lower leg muscles in Garnett's galago, the ring-tailed lemur, and the slow loris were quantified and correlated with positional behaviour. The ankle joint of the galago has a speed-oriented mechanical system, in contrast to that of the slow loris, which exhibits more power-oriented mechanics. The lemur ankle joint exhibited intermediate power arm lengths and an intermediate mechanical advantage relative to the other primates. This result suggests that the mechanical differences in the ankle between the galago and the lemur, taxa that exhibit similar locomotory repertoires, reflect a difference in the kinematics and kinetics of leaping (i.e. generalised vs. specialised leapers). In contrast to leaping primates, lorises have developed a more power-oriented mechanical system as a foot adaptation for positional behaviours such as bridging or cantilevering in their arboreal habitat. © 2013 Anatomical Society.
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Jørgensen, Astrid S; Adogamhe, Pontian E; Laufer, Julia M; Legler, Daniel F; Veldkamp, Christopher T; Rosenkilde, Mette M; Hjortø, Gertrud M
2018-05-16
CCL19 is more potent than CCL21 in inducing chemotaxis of human dendritic cells (DC). This difference is attributed to 1) a stronger interaction of the basic C-terminal tail of CCL21 with acidic glycosaminoglycans (GAGs) in the environment and 2) an autoinhibitory function of this C-terminal tail. Moreover, different receptor docking modes and tissue expression patterns of CCL19 and CCL21 contribute to fine-tuned control of CCR7 signaling. Here, we investigate the effect of the tail of CCL21 on chemokine binding to GAGs and on CCR7 activation. We show that transfer of CCL21-tail to CCL19 (CCL19 CCL21-tail ) markedly increases binding of CCL19 to human dendritic cell surfaces, without impairing CCL19-induced intracellular calcium release or DC chemotaxis, although it causes reduced CCR7 internalization. The more potent chemotaxis induced by CCL19 and CCL19 CCL21-tail compared to CCL21 is not transferred to CCL21 by replacing its N-terminus with that of CCL19 (CCL21 CCL19-N-term ). Measurements of cAMP production in CHO cells uncover that CCL21-tail transfer (CCL19 CCL21-tail ) negatively affects CCL19 potency, whereas removal of CCL21-tail (CCL21 tailless ) increases signaling compared to full-length CCL21, indicating that the tail negatively affects signaling via cAMP. Similar to chemokine-driven calcium mobilization and chemotaxis, the potency of CCL21 in cAMP is not improved by transfer of the CCL19 N-terminus to CCL21 (CCL21 CCL19-N-term ). Together these results indicate that ligands containing CCL21 core and C-terminal tail (CCL21 and CCL21 CCL19-N-term ) are most restricted in their cAMP signaling; a phenotype attributed to a stronger GAG binding of CCL21 and defined structural differences between CCL19 and CCL21. ©2018 Society for Leukocyte Biology.
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Generation of Parametric Equivalent-Area Targets for Design of Low-Boom Supersonic Concepts
NASA Technical Reports Server (NTRS)
Li, Wu; Shields, Elwood
2011-01-01
A tool with an Excel visual interface is developed to generate equivalent-area (A(sub e)) targets that satisfy the volume constraints for a low-boom supersonic configuration. The new parametric Ae target explorer allows users to interactively study the tradeoffs between the aircraft volume constraints and the low-boom characteristics (e.g., loudness) of the ground signature. Moreover, numerical optimization can be used to generate the optimal A(sub e) target for given A(sub e) volume constraints. A case study is used to demonstrate how a generated low-boom Ae target can be matched by a supersonic configuration that includes a fuselage, wing, nacelle, pylon, aft pod, horizontal tail, and vertical tail. The low-boom configuration is verified by sonic-boom analysis with an off-body pressure distribution at three body lengths below the configuration
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Tales told by tails: watching DNA driven through a random medium
NASA Astrophysics Data System (ADS)
Guan, Juan; Wang, Bo; Bae, Sung Chul; Granick, Steve
2013-03-01
DNA ligation is used to label separately the ends and centers of monodisperse DNA 16 μm in contour length, and 2-color fluorescence microscopy is used to follow with nm resolution how chains migrate through agarose networks driven by electric fields, at both whole chain and segment level. We observe that the leading segment is always a physical chain end which stretches and pulls out slack in the still-quiescent remainder of the chain until the other end is taken up. Heads and tails behave strikingly differently: the leading end of migrating chains migrates more smoothly, whereas motion of the trailing end shows intermittent pauses and jerky recoil. None of the mechanisms imagined classically for this situation - chain reptation, hooking or entropic trapping, appears to fully describe these data obtained from single-molecule visualization.
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Vortex systems on slender rotating bodies and their effect on the aerodynamic coefficients
NASA Technical Reports Server (NTRS)
Fiechter, M.
1986-01-01
The turbulent flow of rotational bodies up to a length of 20 diameters with various head shapes and cylindrical tails was examined in the subsonic wind tunnel with the Mach number of M = 0.1. At angles of incidence lower than 30 degrees, a pair of symmetrical eddies rests stationary from head to tail on the trailing side, very close to the body. At angles between 30 and 60 degrees, the stationary eddies are asymmetrically pushed off. Between 60 and 90 degrees, the eddies detach themselves in an instationary manner. This includes, for example, the turbulent flow at the start-up of flying bodies in the presence of lateral winds. The results of measurments obtained by Mello at M = 2, an impulse method, and the cross flow theory according to Allen are used for comparison.
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A new species of Rock Gecko genus Cnemaspis (Squamata: Gekkonidae) from Western Sarawak, Malaysia.
Kurita, Takaki; Nishikawa, Kanto; Matsui, Masafumi; Hikida, Tsutomu
2017-05-03
A new species of Asian rock gecko, genus Cnemaspis, is described from Padawan, western Sarawak, Malaysian Borneo. The new species forms a clade with C. paripari and C. nigridia of the C. nigridia group in a mitochondrial DNA phylogeny and is similar to them morphologically in some characters such as caudal scalation. It differs from the other Asian Cnemaspis species in its unique combination of snout-vent length (up to 62.7 mm), 4-9 precloacal pores in males, keeled subcaudals with an enlarged, smooth, median row, presence of ventrolateral caudal tubercles, and coloration (head and upper flanks dark-yellow; anterior portion of tail black; posterior portion of tail white with black, paravertebral blob). Phylogenetic relationships within the C. nigridia group and the distributional ranges of species within the group suggest allopatric speciation by geographic isolation.
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Dorazio, Robert M.; Connor, Edward F.
2014-01-01
We developed a statistical model to estimate the abundances of potentially interacting species encountered while conducting point-count surveys at a set of ecologically relevant locations - as in a metacommunity of species. In the model we assume that abundances of species with similar traits (e.g., body size) are potentially correlated and that these correlations, when present, may exist among all species or only among functionally related species (such as members of the same foraging guild). We also assume that species-specific abundances vary among locations owing to systematic and stochastic sources of heterogeneity. For example, if abundances differ among locations due to differences in habitat, then measures of habitat may be included in the model as covariates. Naturally, the quantitative effects of these covariates are assumed to differ among species. Our model also accounts for the effects of detectability on the observed counts of each species. This aspect of the model is especially important for rare or uncommon species that may be difficult to detect in community-level surveys. Estimating the detectability of each species requires sampling locations to be surveyed repeatedly using different observers or different visits of a single observer. As an illustration, we fitted models to species-specific counts of birds obtained while sampling an avian community during the breeding season. In the analysis we examined whether species abundances appeared to be correlated due to similarities in morphological measures (body mass, beak length, tarsus length, wing length, tail length) and whether these correlations existed among all species or only among species of the same foraging guild. We also used the model to estimate the effects of forested area on species abundances and the effects of sound power output (as measured by body size) on species detection probabilities.
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García-Navas, Vicente; Rodríguez-Rey, Marta; Marki, Petter Z; Christidis, Les
2018-04-01
Interspecific competition is thought to play a key role in determining the coexistence of closely related species within adaptive radiations. Competition for ecological resources can lead to different outcomes from character displacement to, ultimately, competitive exclusion. Accordingly, divergent natural selection should disfavor those species that are the most similar to their competitor in resource use, thereby increasing morphological disparity. Here, we examined ecomorphological variability within an Australo-Papuan bird radiation, the Acanthizidae, which include both allopatric and sympatric complexes. In addition, we investigated whether morphological similarities between species are related to environmental factors at fine scale (foraging niche) and/or large scale (climate). Contrary to that predicted by the competition hypothesis, we did not find a significant correlation between the morphological similarities found between species and their degree of range overlap. Comparative modeling based on both a priori and data-driven identification of selective regimes suggested that foraging niche is a poor predictor of morphological variability in acanthizids. By contrast, our results indicate that climatic conditions were an important factor in the formation of morphological variation. We found a significant negative correlation between species scores for PC1 (positively associated to tarsus length and tail length) and both temperature and precipitation, whereas PC2 (positively associated to bill length and wing length) correlated positively with precipitation. In addition, we found that species inhabiting the same region are closer to each other in morphospace than to species outside that region regardless of genus to which they belong or its foraging strategy. Our results indicate that the conservative body form of acanthizids is one that can work under a wide variety of environments (an all-purpose morphology), and the observed interspecific similarity is probably driven by the common response to environment.
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Huang, Lige; Li, Yuanyuan; Zhao, Man; Chao, Yuanqing; Qiu, Rongliang; Yang, Yanhua
2018-01-01
To explore the effect of different biochars on Cassia alata L. growth and heavy metal immobilization in multi-metal mine tailings, a 100-day pot experiment was conducted. Three biochars derived from Hibiscus cannabinus core (HB), sewage sludge (SB) and chicken manure (MB), were added to mine tailings at rates of 0.4%, 1% and 3% (w/w). The results showed that the root biomass, shoot biomass, plant height and root length were 1.2–2.8, 1.7–3.2, 1–1.5 and 1.6–3.3 times of those in the control group, respectively. Pb, Zn, Cu, Cd and As contents in the shoot decreased by 63.9–89.5%, 46.9–66.0%, 32.7–62.4%, 40.4–76.4% and 54.9–77.5%, respectively. The biochar significantly increased the pH and decreased the mild acid-soluble Pb and Cu concentrations in the mine tailings. Specifically, SB immobilized Pb and Cu better than MB and HB did, although it did not immobilize As, Zn or Cd. Meanwhile, more attention should be paid to the potential As release as the biochar application rate increases. In conclusion, Cassia alata L. coupled with 3% of SB could be an effective measure for restoring multi-metal mine tailings. This study herein provided a promising ecological restoration technique for future practice of heavy metal stabilization in mine tailings. PMID:29534505
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Fernández-Fueyo, Elena; Acebes, Sandra; Ruiz-Dueñas, Francisco J.; ...
2014-11-22
The genome ofCeriporiopsis subvermisporaincludes 13 manganese peroxidase (MnP) genes representative of the three subfamilies described in ligninolytic fungi, which share an Mn 2+-oxidation site and have varying lengths of the C-terminal tail. We expressed short, long and extralong MnPs heterologously and biochemically characterized, and the first structure of an extralong MnP was solved. Its C-terminal tail surrounds the haem-propionate access channel, contributing to Mn 2+oxidation by the internal propionate, but prevents the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), which is only oxidized by short MnPs and by shortened-tail variants from site-directed mutagenesis. Furthermore, the tail, which is anchored by numerous contacts, notmore » only affects the catalytic properties of long/extralong MnPs but is also associated with their high acidic stability. Cd 2+binds at the Mn 2+-oxidation site and competitively inhibits oxidation of both Mn 2+and ABTS. Moreover, mutations blocking the haem-propionate channel prevent substrate oxidation. This agrees with molecular simulations that position ABTS at an electron-transfer distance from the haem propionates of anin silicoshortened-tail form, while it cannot reach this position in the extralong MnP crystal structure. Small differences exist between the long and the extralong MnPs, which do not justify their classification as two different subfamilies, but they significantly differ from the short MnPs, with the presence/absence of the C-terminal tail extension being implicated in these differences.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Berbís, M. Álvaro; André, Sabine; Cañada, F. Javier
2014-01-03
Highlights: •Galectin-3 is composed of a carbohydrate recognition domain and an N-terminal tail. •Synthetic peptides derived from the tail are shown to interact with the CRD. •This interaction is modulated by Ser- and Tyr-phosphorylation of the peptides. -- Abstract: Galectin-3 (Gal-3) is a multi-functional effector protein that functions in the cytoplasm and the nucleus, as well as extracellularly following non-classical secretion. Structurally, Gal-3 is unique among galectins with its carbohydrate recognition domain (CRD) attached to a rather long N-terminal tail composed mostly of collagen-like repeats (nine in the human protein) and terminating in a short non-collagenous terminal peptide sequence uniquemore » in this lectin family and not yet fully explored. Although several Ser and Tyr sites within the N-terminal tail can be phosphorylated, the physiological significance of this post-translational modification remains unclear. Here, we used a series of synthetic (phospho)peptides derived from the tail to assess phosphorylation-mediated interactions with {sup 15}N-labeled Gal-3 CRD. HSQC-derived chemical shift perturbations revealed selective interactions at the backface of the CRD that were attenuated by phosphorylation of Tyr 107 and Tyr 118, while phosphorylation of Ser 6 and Ser 12 was essential. Controls with sequence scrambling underscored inherent specificity. Our studies shed light on how phosphorylation of the N-terminal tail may impact on Gal-3 function and prompt further studies using phosphorylated full-length protein.« less
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Fishnet statistics for probabilistic strength and scaling of nacreous imbricated lamellar materials
NASA Astrophysics Data System (ADS)
Luo, Wen; Bažant, Zdeněk P.
2017-12-01
Similar to nacre (or brick masonry), imbricated (or staggered) lamellar structures are widely found in nature and man-made materials, and are of interest for biomimetics. They can achieve high defect insensitivity and fracture toughness, as demonstrated in previous studies. But the probability distribution with a realistic far-left tail is apparently unknown. Here, strictly for statistical purposes, the microstructure of nacre is approximated by a diagonally pulled fishnet with quasibrittle links representing the shear bonds between parallel lamellae (or platelets). The probability distribution of fishnet strength is calculated as a sum of a rapidly convergent series of the failure probabilities after the rupture of one, two, three, etc., links. Each of them represents a combination of joint probabilities and of additive probabilities of disjoint events, modified near the zone of failed links by the stress redistributions caused by previously failed links. Based on previous nano- and multi-scale studies at Northwestern, the strength distribution of each link, characterizing the interlamellar shear bond, is assumed to be a Gauss-Weibull graft, but with a deeper Weibull tail than in Type 1 failure of non-imbricated quasibrittle materials. The autocorrelation length is considered equal to the link length. The size of the zone of failed links at maximum load increases with the coefficient of variation (CoV) of link strength, and also with fishnet size. With an increasing width-to-length aspect ratio, a rectangular fishnet gradually transits from the weakest-link chain to the fiber bundle, as the limit cases. The fishnet strength at failure probability 10-6 grows with the width-to-length ratio. For a square fishnet boundary, the strength at 10-6 failure probability is about 11% higher, while at fixed load the failure probability is about 25-times higher than it is for the non-imbricated case. This is a major safety advantage of the fishnet architecture over particulate or fiber reinforced materials. There is also a strong size effect, partly similar to that of Type 1 while the curves of log-strength versus log-size for different sizes could cross each other. The predicted behavior is verified by about a million Monte Carlo simulations for each of many fishnet geometries, sizes and CoVs of link strength. In addition to the weakest-link or fiber bundle, the fishnet becomes the third analytically tractable statistical model of structural strength, and has the former two as limit cases.
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Winkfein, R J; Nishikawa, S; Connor, W; Dixon, G H
1993-07-01
A synthetic oligonucleotide primer, designed from marsupial protamine protein-sequence data [Balhorn, R., Corzett, M., Matrimas, J. A., Cummins, J. & Faden, B. (1989) Analysis of protamines isolated from two marsupials, the ring-tailed wallaby and gray short-tailed opossum, J. Cell. Biol. 107] was used to amplify, via the polymerase chain reaction, protamine sequences from a North American opossum (Didelphis marsupialis) cDNA. Using the amplified sequences as probes, several protamine cDNA clones were isolated. The protein sequence, predicted from the cDNA sequences, consisted of 57 amino acids, contained a large number of arginine residues and exhibited the sequence ARYR at its amino terminus, which is conserved in avian and most eutherian mammal protamines. Like the true protamines of trout and chicken, the opossum protamine lacked cysteine residues, distinguishing it from placental mammalian protamine 1 (P1 or stable) protamines. Examination of the protamine gene, isolated by polymerase-chain-reaction amplification of genomic DNA, revealed the presence of an intron dividing the protamine-coding region, a common characteristic of all mammalian P1 genes. In addition, extensive sequence identity in the 5' and 3' flanking regions between mouse and opossum sequences classify the marsupial protamine as being closely related to placental mammal P1. Protamine transcripts, in both birds and mammals, are present in two size classes, differing by the length of their poly(A) tails (either short or long). Examination of opossum protamine transcripts by Northern hybridization revealed four distinct mRNA species in the total RNA fraction, two of which were enriched in the poly(A)-rich fraction. Northern-blot analysis, using an intron-specific probe, revealed the presence of intron sequences in two of the four protamine transcripts. If expressed, the corresponding protein from intron-containing transcripts would differ from spliced transcripts by length (49 versus 57 amino acids) and would contain a cysteine residue.
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Yomantas, Yurgis A V; Abalakina, Elena G; Lobanova, Juliya S; Mamontov, Victor A; Stoynova, Nataliya V; Mashko, Sergey V
2018-05-15
The genomes of two new lytic phages of Corynebacterium glutamicum ATCC 13032, φ673 and φ674, were sequenced and annotated (GenBank: MG324353, MG324354). Electron microscopy studies of both virions revealed that taxonomically they belong to the Siphoviridae family and have a polyhedral head with a width of 50 nm and a non-contractile tail with a length of 250 nm. The genomes of φ673 and φ674 consist of linear double-stranded DNA molecules with lengths of 44,530 bp (G+C = 51.1%) and 43,193 bp (G+C = 50.7%) and identical, protruding, cohesive 3' ends 13 nt in length. The level of identity between the φ673 and φ674 genomes is 85.2%. Two major structural proteins of each virion were separated via SDS-PAGE and identified using peptide mass fingerprinting. Based on bioinformatic analysis, 56 and 54 ORFs were predicted for φ673 and φ674, respectively. Only 20 of the putative gene products of φ673 and 20 of φ674 could be assigned to known functions. Both genomes were divided into functional modules. Nine putative promoters in the φ673 genome and eight in the φ674 genome were predicted. One bidirectional Rho-independent transcription terminator was identified and experimentally confirmed in each phage genome.
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Inoue, Masako; Shimura, Ryoji; Uebayashi, Akiko; Ikoma, Shinobu; Iima, Hiroko; Sumiyoshi, Takashi; Teraoka, Hiroki; Makita, Kohei; Hiraga, Takeo; Momose, Kunikazu; Masatomi, Hiroyuki
2013-01-01
Red-crowned (or Japanese) cranes Grus japonensis are native to eastern Hokkaido, Japan--the island population, and mainland Asia--the continental population that migrates from breeding grounds along the Amur River Basin to winter in east China and the Korean Peninsula. The island population was reduced to about 50-60 birds in early part of the 20th century. Since 1950s, the population has increased to more than 1,300 as a consequence of human-provided food in winter, resulted in change of their habitats and food resource. From the carcasses of 284 wild cranes from the island population, collected in Hokkaido since 1976 until 2010, we measured six physical parameters (body weight and lengths of body, wing, tarsus, tail and exposed culmen) and divided into groups by sex and three developmental stages (juvenile, yearling and adult). All parameters of males were larger than those of females at the same stage. Total body length of females tends to grow up earlier than males, in contrast to body weight. Obvious time trends were not observed in these all parameters during 34 years for these six categories measured, except total length of male juveniles, which showed a significant increasing trend. These results provide the first extensive data on body size and mass in the wild red-crowned cranes.
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Elshishka, Milka; Lazarova, Stela; Peneva, Vlada K.
2012-01-01
Abstract Two nematode species of the genus Enchodelus Thorne, 1939, one new and one known from Arctic polar deserts were studied. Enchodelus makarovae sp. n. is an amphimictic species, characterised by females with body length of 1.57–2.00 mm, lip region 15–17.5 µm wide, amphid duplex, odontostyle 38–43 µm long or 2.3–2.8 times lip region diam. Odontophore with flanges, 1.2–1.4 times as long as odontostyle; pharynx length 320–377 µm, pharyngeal expansion 113–130 µm long or 32–37% of total pharynx length; female genital system amphidelphic, uterus tripartite, pars refringens vaginae with two trapezoid sclerotisations, vulva a transverse slit (V=45–51%); tail bluntly conoid (25–35 µm, c=45.8–70.3, c’=0.6–0.9 in females, and 29–33 µm, c=46.4–58.9, c’=0.7–0.8 in males). Males with 65–74 µm long spicules and 10–12 spaced ventromedian supplements. Additional information for Enchodelus groenlandicus is provided, this being a new geographic record for the Putorana Plateau, Russian Arctic. PMID:22933846
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Mathews, Patrick D; Maia, Antônio A M; Adriano, Edson A
2016-09-01
A new species of myxozoan, Henneguya melini sp. n. (Myxosporea: Myxobolidae), was described based on morphologic and ultrastructural features. This is a parasite of the ornamental freshwater fish C. melini from the Rio Negro, and it was found in five of 30 (16.7 %) C. melini examined. The parasite was found in the gill filaments, and the plasmodia had form of round to ellipsoid, with mature and immature spores inside them. The average spore body was 15.5 ± 0.2 μm in length, 4.7 ± 0.1 μm in width, and the tail measured 25.3 ± 0.1 μm in length. The spores showed typical features of the genus Henneguya, with two valves of equal size and two symmetrical polar capsules of 4.8 ± 0.7 μm in length and 1.7 ± 0.3 μm in width. Each polar capsule had a polar filament with five to six turns. Based on morphology (morphologic and ultrastructural data) of the plasmodia and spores and the fact that this is the first report of a Henneguya species in a fish species of the genus Corydoras, it was considered a new myxozoan species.
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Apparent power-law distributions in animal movements can arise from intraspecific interactions
Breed, Greg A.; Severns, Paul M.; Edwards, Andrew M.
2015-01-01
Lévy flights have gained prominence for analysis of animal movement. In a Lévy flight, step-lengths are drawn from a heavy-tailed distribution such as a power law (PL), and a large number of empirical demonstrations have been published. Others, however, have suggested that animal movement is ill fit by PL distributions or contend a state-switching process better explains apparent Lévy flight movement patterns. We used a mix of direct behavioural observations and GPS tracking to understand step-length patterns in females of two related butterflies. We initially found movement in one species (Euphydryas editha taylori) was best fit by a bounded PL, evidence of a Lévy flight, while the other (Euphydryas phaeton) was best fit by an exponential distribution. Subsequent analyses introduced additional candidate models and used behavioural observations to sort steps based on intraspecific interactions (interactions were rare in E. phaeton but common in E. e. taylori). These analyses showed a mixed-exponential is favoured over the bounded PL for E. e. taylori and that when step-lengths were sorted into states based on the influence of harassing conspecific males, both states were best fit by simple exponential distributions. The direct behavioural observations allowed us to infer the underlying behavioural mechanism is a state-switching process driven by intraspecific interactions rather than a Lévy flight. PMID:25519992
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Score distributions of gapped multiple sequence alignments down to the low-probability tail
NASA Astrophysics Data System (ADS)
Fieth, Pascal; Hartmann, Alexander K.
2016-08-01
Assessing the significance of alignment scores of optimally aligned DNA or amino acid sequences can be achieved via the knowledge of the score distribution of random sequences. But this requires obtaining the distribution in the biologically relevant high-scoring region, where the probabilities are exponentially small. For gapless local alignments of infinitely long sequences this distribution is known analytically to follow a Gumbel distribution. Distributions for gapped local alignments and global alignments of finite lengths can only be obtained numerically. To obtain result for the small-probability region, specific statistical mechanics-based rare-event algorithms can be applied. In previous studies, this was achieved for pairwise alignments. They showed that, contrary to results from previous simple sampling studies, strong deviations from the Gumbel distribution occur in case of finite sequence lengths. Here we extend the studies to multiple sequence alignments with gaps, which are much more relevant for practical applications in molecular biology. We study the distributions of scores over a large range of the support, reaching probabilities as small as 10-160, for global and local (sum-of-pair scores) multiple alignments. We find that even after suitable rescaling, eliminating the sequence-length dependence, the distributions for multiple alignment differ from the pairwise alignment case. Furthermore, we also show that the previously discussed Gaussian correction to the Gumbel distribution needs to be refined, also for the case of pairwise alignments.
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NASA Astrophysics Data System (ADS)
Katija, Kakani; Sherman, Alana; Robison, Bruce
2016-11-01
The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet remains one of the least explored. Little-known marine organisms that inhabit midwater have developed life strategies that contribute to their evolutionary success, and may inspire engineering solutions for societally relevant challenges. A group of midwater organisms, known as giant larvaceans (genus Bathochordaeus), beat their tails to drive food and particle-laden water through complex, mucus filtering structures to feed. Giant larvaceans, whose motion and kinematics resemble flapping flexible foils, range in size from 1 to 10 cm in length, and can be found between the surface and 400 m. Using remotely-operated vehicles and DeepPIV, an instrument that enables in situ particle image velocimetry (PIV) measurements, the filtration rates and kinematics of giant larvaceans were investigated. These measurements yielded filtration rates for giant larvaceans as high as 80 L/hr, which exceeds expected filtration rates by a factor of 2 when compared with other larvacean groups. Comparing tail kinematics between Bathochordeaus and smaller larvaceans reveals differences in tail bending modes, where a hinge is present throughout the tail beat in giant larvaceans. Using laboratory PIV measurements with swimming animals and soft-bodied mechanical mimics, we reveal how these differences in tail kinematics can lead to enhanced fluid transport. This work has been supported by the Packard Foundation.
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Coupling between the Dynamics of Water and Surfactants in Lyotropic Liquid Crystals.
McDaniel, Jesse G; Yethiraj, Arun
2017-05-18
Bilayers composed of lipid or surfactant molecules are central to biological membranes and lamellar lyotropic liquid crystalline (LLC) phases. Common to these systems are phases that exhibit either ordered or disordered packing of the hydrophobic tails. In this work, we study the impact of surfactant ordering, i.e., disordered L α and ordered L β LLC phases, on the dynamics of water and sodium ions in the lamellar phases of dicarboxylate gemini surfactants. We study the different phases at identical hydration levels by changing the length of the hydrophobic tails; surfactants with shorter tails form L α phases and those with longer tails form L β phases. We find that the L α phases exhibit lower density and greater compressibility than the L β phases, with a hydration-dependent headgroup surface area. These structural differences significantly affect the relative dynamic properties of the phases, primarily the mobility of the surfactant molecules tangential to the bilayer surface, as well as the rates of water and ion diffusion. We find ∼20-50% faster water diffusion in the L α phases compared to the L β phases, with the differences most pronounced at low hydration. This coupling between water dynamics and surfactant mobility is verified using additional simulations in which the surfactant tails are frozen. Our study indicates that gemini surfactant LLCs provide an important prototypical system for characterizing properties shared with more complex biological lipid membranes.
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Novel dicistrovirus from bat guano.
Reuter, Gábor; Pankovics, Péter; Gyöngyi, Zoltán; Delwart, Eric; Boros, Akos
2014-12-01
A novel dicistrovirus (strain NB-1/2011/HUN, KJ802403) genome was detected from guano collected from an insectivorous bat (species Pipistrellus pipistrellus) in Hungary, using viral metagenomics. The complete genome of NB-1 is 9136 nt in length, excluding the poly(A) tail. NB-1 has a genome organization typical of a dicistrovirus with multiple 3B(VPg) and a cripavirus-like intergenic region (IGR)-IRES. NB-1 shares only 41 % average amino acid sequence identity with capsid proteins of Himetobi P virus, indicating a potential novel species in the genus Cripavirus, family Dicistroviridae.
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Darrow, D S; Cecil, F E; Kiptily, V; Fullard, K; Horton, A; Murari, A
2010-10-01
The loss of MeV alpha particles from JET plasmas has been measured with a set of thin foil Faraday cup detectors during third harmonic heating of helium neutral beam ions. Tail temperatures of ∼ 2 MeV have been observed, with radial scrape off lengths of a few centimeters. Operational experience from this system indicates that such detectors are potentially feasible for future large tokamaks, but careful attention to screening rf and MHD induced noise is essential.
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Diaby, Nouhou; Dold, Bernhard; Pfeifer, Hans-Rudolf; Holliger, Christof; Johnson, D Barrie; Hallberg, Kevin B
2007-02-01
The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) 'oxidation zone' characterized by low-pH (2.5-4), a 'neutralization zone' (70-80 to 300-400 cm) and an unaltered 'primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (10(9) g(-1) dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium-like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment.
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NASA Technical Reports Server (NTRS)
Lin, N.; Walker, R. J.; Mcpherron, R. L.; Kivelson, M. G.
1990-01-01
During the 1054 UT CDAW 6 substorm event, two ISEE spacecraft observed dynamic changes in the magnetic field and in the flux of energetic particles in the near-earth plasma sheet. In the substorm growth phase, the magnetic field at both ISEE spacecraft became tail-like. Following expansion phase onset, two small scale magnetic islands were observed moving tailward at a velocity of about 580 km/s. The passage of these two magnetic islands was coincident with bursts of tailward streaming energetic particles. The length of the magnetic loops was estimated to have been about 2 to 3 earth radii while the height of the loops was less than 0.5 earth radii. The magnetic islands were produced by multipoint reconnection processes in the near tail plasma sheet which may have been associated with the formation of the near-earth neutral line and the subsequent formation of a large scale plasmoid. The near-earth neutral line retreated tailward later in the expansion phase, as suggested by the reversal of the streaming of energetic particles.
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Baş, Hatice; Kalender, Yusuf; Pandir, Dilek; Kalender, Suna
2015-05-01
The adverse effects of lead nitrate (LN) and the preventive role of sodium selenite were investigated in diabetic and non-diabetic rat blood by measuring trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) also by evaluating DNA damage with comet assay. LN increased the levels of MDA, tail DNA%, mean tail length and tail moment, decreased the enzymes activities, FRAP and TEAC values. In sodium selenite+LN group, we observed the protective effect of sodium selenite on examining parameters. Diabetes caused alterations on these parameters, too. We found that sodium selenite did not protect against diabetes caused damages. As a result, LN caused toxic effects on blood cells and sodium selenite alleviated this toxicity but it did not show preventive effect against diabetes. Also, LN caused more harmfull effects in diabetic groups than non-diabetic groups. Copyright © 2015 Elsevier B.V. All rights reserved.
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Reliability of fish size estimates obtained from multibeam imaging sonar
Hightower, Joseph E.; Magowan, Kevin J.; Brown, Lori M.; Fox, Dewayne A.
2013-01-01
Multibeam imaging sonars have considerable potential for use in fisheries surveys because the video-like images are easy to interpret, and they contain information about fish size, shape, and swimming behavior, as well as characteristics of occupied habitats. We examined images obtained using a dual-frequency identification sonar (DIDSON) multibeam sonar for Atlantic sturgeon Acipenser oxyrinchus oxyrinchus, striped bass Morone saxatilis, white perch M. americana, and channel catfish Ictalurus punctatus of known size (20–141 cm) to determine the reliability of length estimates. For ranges up to 11 m, percent measurement error (sonar estimate – total length)/total length × 100 varied by species but was not related to the fish's range or aspect angle (orientation relative to the sonar beam). Least-square mean percent error was significantly different from 0.0 for Atlantic sturgeon (x̄ = −8.34, SE = 2.39) and white perch (x̄ = 14.48, SE = 3.99) but not striped bass (x̄ = 3.71, SE = 2.58) or channel catfish (x̄ = 3.97, SE = 5.16). Underestimating lengths of Atlantic sturgeon may be due to difficulty in detecting the snout or the longer dorsal lobe of the heterocercal tail. White perch was the smallest species tested, and it had the largest percent measurement errors (both positive and negative) and the lowest percentage of images classified as good or acceptable. Automated length estimates for the four species using Echoview software varied with position in the view-field. Estimates tended to be low at more extreme azimuthal angles (fish's angle off-axis within the view-field), but mean and maximum estimates were highly correlated with total length. Software estimates also were biased by fish images partially outside the view-field and when acoustic crosstalk occurred (when a fish perpendicular to the sonar and at relatively close range is detected in the side lobes of adjacent beams). These sources of bias are apparent when files are processed manually and can be filtered out when producing automated software estimates. Multibeam sonar estimates of fish size should be useful for research and management if these potential sources of bias and imprecision are addressed.
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Nasira, K; Shahina, F; Firoza, K
2013-06-01
Deladenus cocophilus n. sp. was isolated from infested coconut fruits in Winder, Balochistan, Pakistan. Descriptions are given of the entomophagous (insect-parasitic females) and mycetophagous (fungus-feeding) free-living females, males, and juveniles. The new species D. cocophilus resembles those species in which the excretory pore is situated anterior to the hemizonid, namely, D. apopkaetusChitambar, 1991; D. leptosomaGagarin, 2001; D. ipiniMassey, 1974; D. laricis (Blinova and Korentchenko, 1986) Ebsarry, 1991; D. (siricidicola) caniiBedding, 1974; D. (s) imperialisBedding, 1974; D. nevexiiBedding, 1974; D. (wilsoni) proximusBedding, 1974; D. (s) rudyiBedding, 1974; D. (s) siricidicolaBedding, 1968; D. (wilsoni) wilsoniBedding, 1968 and D. minimus Chizhov and Sturhan, 1998. The new species differs from D. ipini in the absence of a post uterine sac vs. present; a = 17 to 30 vs. 35 to 40; stylet = 8 to 10 vs. 11 to 12 μm and vulva-anus = 21 to 28 vs. 35 to 48 μm. From D. apopkaetus it differs in tail length in female 22 to 28 vs. 31 to 43 μm and in the male it is 24 to 32 vs. 30 to 46 μm. It differs from D. leptosoma in the c ratio in females, c = 21 to 37 vs. 16 to 22, presence of 6 lines in lateral field vs. 10 lines and slightly longer spicules 16 to 18 vs. 15 to 16 μm. From D. laricis it differs in a shorter stylet length 8 to 10 vs. 11 to 12 μm; in the c ratio in males 16 to 22 vs. 22 to 35 and hemizonid from anterior end 76 to 90 vs. 90 to 119 μm. It also differs from the following species: D. (siricidicola) canii; D. (s) imperialis; D. nevexii; D. (wilsoni) proximus; D. (s) rudyi; D. (s) siricidicola; D. (wilsoni) wilsoni and D. minimus in having shorter tail length, lower values of a,b,c ratios and a slightly anteriorly located vulva in females.
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Nasira, K.; Shahina, F.; Firoza, K.
2013-01-01
Deladenus cocophilus n. sp. was isolated from infested coconut fruits in Winder, Balochistan, Pakistan. Descriptions are given of the entomophagous (insect-parasitic females) and mycetophagous (fungus-feeding) free-living females, males, and juveniles. The new species D. cocophilus resembles those species in which the excretory pore is situated anterior to the hemizonid, namely, D. apopkaetus Chitambar, 1991; D. leptosoma Gagarin, 2001; D. ipini Massey, 1974; D. laricis (Blinova and Korentchenko, 1986) Ebsarry, 1991; D. (siricidicola) canii Bedding, 1974; D. (s) imperialis Bedding, 1974; D. nevexii Bedding, 1974; D. (wilsoni) proximus Bedding, 1974; D. (s) rudyi Bedding, 1974; D. (s) siricidicola Bedding, 1968; D. (wilsoni) wilsoni Bedding, 1968 and D. minimus Chizhov and Sturhan, 1998. The new species differs from D. ipini in the absence of a post uterine sac vs. present; a = 17 to 30 vs. 35 to 40; stylet = 8 to 10 vs. 11 to 12 μm and vulva-anus = 21 to 28 vs. 35 to 48 μm. From D. apopkaetus it differs in tail length in female 22 to 28 vs. 31 to 43 μm and in the male it is 24 to 32 vs. 30 to 46 μm. It differs from D. leptosoma in the c ratio in females, c = 21 to 37 vs. 16 to 22, presence of 6 lines in lateral field vs. 10 lines and slightly longer spicules 16 to 18 vs. 15 to 16 μm. From D. laricis it differs in a shorter stylet length 8 to 10 vs. 11 to 12 μm; in the c ratio in males 16 to 22 vs. 22 to 35 and hemizonid from anterior end 76 to 90 vs. 90 to 119 μm. It also differs from the following species: D. (siricidicola) canii; D. (s) imperialis; D. nevexii; D. (wilsoni) proximus; D. (s) rudyi; D. (s) siricidicola; D. (wilsoni) wilsoni and D. minimus in having shorter tail length, lower values of a,b,c ratios and a slightly anteriorly located vulva in females. PMID:23833325
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Genetic and environmental effects on morphology and asexual reproduction in the moss, Bryum bicolor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Shaw, A.J.
A distinctive form of Bryum bicolor, characterized by stoutly excurrent costae and abundant asexual gemmae, occurs on heavy metal-contaminated tailings of the Conrad Hill Mine in the Piedmont of North Carolina. Plants from two mine site populations, plus two other populations from Richmond, Virginia, were grown on three types of soil in order to determine the degree to which morphological traits, including the number of gemmae per plant, can be modified by substrate. All populations grew equally well in the mine soil, and there was no evidence that plants from the mine site populations were physiologically adapted for growth onmore » the contaminated tailings. Leaf dimensions, costa length, and number of gemmae per stem were strongly influenced by substrate, although some differences between populations were maintained under experimental conditions. Populations also differed in the efficacy with which plants regenerated from gametophytic fragments.« less
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BVR photometric investigation of galaxy pair KPG 562
NASA Astrophysics Data System (ADS)
Hendy, Y. H. M.
2018-06-01
This work presents BVR photometric observations and analyses for galaxy pair KPG 562 selected from the Karachentsev Catalog of Isolated Pairs of Galaxies. The observations were obtained using the 1.88-m Telescope of the Kottamia Astronomical Observatory (KAO), Egypt. There is no interaction signs assigned for this pair as reported by Karachentsev Catalog. We used the surface photometry technique to obtain photometric parameters for each galaxy of the pair. The isophotal contours, the luminosity profiles, color profiles (B-V, V-R), ellipticity profiles, position angle (PA) profiles and isophotal center-shift (xc, yc) profiles have been presented. The total and absolute magnitude, ellipticity and position angle (PA) were also obtained from the studied galaxy pair. The studied galaxy pair is clearly showing signs of interaction opposed to that found by Karachentsev. We found that the galaxy KPG 562b contains one tidal tail. The length and thickness of tidal tail were obtained and presented in this study.
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NASA Technical Reports Server (NTRS)
Fusi Pecci, F.; Ferraro, F. R.; Bellazzini, M.; Djorgovski, S.; Piotto, G.; Buonanno, R.
1993-01-01
Possible relationships between horizontal branch (HB) morphology in Galactic globular clusters and the cluster structure and dynamical evolution are investigated. New HB observables are defined and determined using a theoretical framework deduced from HB models. Data for 53 Galactic globular clusters are used to obtain correlations between the observables. It is found that the net length of the HB and the presence and extent of blue tails in particular are correlated with the cluster density and concentrations, in the sense of more concentrated or denser clusters having bluer and longer HB morphologies. This effect is especially strong for the intermediate metallicity clusters. Thus, the cluster environment can affect the stellar evolution leading to the HB and therefore the HB morphology. This result is interpreted in terms of an enhanced mass removal from the HB progenitors.
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Xu, Yu Mei; Zhao, Zeng Qi; Davies, Kerrie A; Wang, Jian Ming
2017-04-03
This paper describes a new species of Tripylella and gives a new record of Tripyla (family Tripylidae) in Australia, and provides a key to species in the genus Tripylella. Tripylella australis sp. nov. is characterized by having females with a long body (1804-1832 μm), a=41-42, b= 4.4-4.5, c=10.3-11.3, c'=5.4-6.4 and V=51-54%, outer labial setae 13-14 μm long and cephalic setae 3.7-4.5 μm long in one whorl, dorsal tooth posterior to two subventral teeth, tail tapering uniformly, and four single caudal setae on the dorsal part of the tail. Males are similar to females, and have a long body (1870-2014 μm), a=50-55, b= 4.7-4.9, c=11.3-11.4, c'=5.8-6.0 and T=53-56%, horn-shaped spicules, 36-38 μm long, a straight gubernaculum 14-16 μm in length, tail tapering almost uniformly, and four caudal setae on the dorsal part of the tail. A key for identification of Tripylella species is presented. Tripyla setifera Bütschli 1873 is recorded for the first time in Australia, and is re-described.
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The effect of oil sands tailings pond sediments on embryo-larval walleye (Sander vitreus).
Raine, J C; Turcotte, D; Tumber, V; Peru, K M; Wang, Z; Yang, C; Headley, J V; Parrott, J L
2017-10-01
Walleye (Sander vitreus) are a commercially important North American fish species that inhabit the Athabasca River. This river flows through the Athabasca oil sands where natural sources of bitumen erode from the McMurray formation. Little information is available on responses of walleye embryos to oil sands tailings pond sediments in a laboratory setting. The current study describes the design and implementation of a daily-renewal bioassay to assess the potential effects of tailings pond sediments from the Athabasca oil sands area on walleye development. Developing walleye embryos were exposed to increasing concentrations of two tailings pond sediments (collected in the Athabasca oil sands area) until the completion of yolk absorption in control fish. Sediments from the tailings pond represent a mixture of polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs. During the 31 day exposure, the walleye were examined for mortalities, weight, length and developmental abnormalities to provide an initial evaluation of the effects of the oil sands tailings pond sediments. Walleye embryo survival differed between the tailings pond sediments, and survival decreased with increasing sediment concentration. Alkylated PAH content differed between the two tailings pond sediments and lower embryo survival corresponded to higher total and alkylated PAH content. Tailings pond sediment-exposed walleye exhibited a delay in development, as well as increased percentages of larvae with heart and yolk sac edema, and cranial and spinal malformations. These abnormalities in development are often associated with PAH and alkylated PAH exposure. This study provides an exposure design that can be used to assess sediment toxicity to early developmental stages of a fish species not commonly tested in the lab, and lays the groundwork for future studies with this and other difficult-to-culture species. These results offer information on the potential effects of tailings pond sediments containing PAH/alkylated PAH mixtures on walleye development and survival. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.
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Bronstein, Lyudmila M.; Shtykova, Eleonora V.; Malyutin, Andrey; Dyke, Jason C.; Gunn, Emily; Gao, Xinfeng; Stein, Barry; Konarev, Peter V.; Dragnea, Bogdan; Svergun, Dmitri I.
2010-01-01
Iron oxide nanoparticles (NPs) with a diameter 21.6 nm were coated with poly(maleic acid-alt-1-octadecene) (PMAcOD) modified with grafted 5,000 Da poly(ethyelene glycol) (PEG) or short ethylene glycol (EG) tails. The coating procedure utilizes hydrophobic interactions of octadecene and oleic acid tails, while the hydrolysis of maleic anhydride moieties as well as the presence of hydrophilic PEG (EG) tails allows the NP hydrophilicity. The success of the NP coating was found to be independent of the degree of grafting which was varied between 20 and 80% of the –MacOD-units, but depended on the length of the grafted tail. The NP coating and hydrophilization did not occur when the modified copolymer contained 750 Da PEG tails independently of the grafting degree. To explain this phenomenon the micellization of the modified PMAcOD copolymers in water was analyzed by small angle x-ray scattering (SAXS). The PMAcOD molecules with the grafted 750 Da PEG tails form compact non-interacting disk-like micelles, whose stability apparently allows for no interactions with the NP hydrophobic shells. The PMAcOD containing the 5,000 Da PEG and EG tails form much larger aggregates capable of an efficient coating of the NPs. The coated NPs were characterized using transmission electron microscopy, dynamic light scattering, ζ-potential measurements, and thermal gravimetry analysis. The latter method demonstrated that the presence of long PEG tails in modified PMAcOD allows the attachment of fewer macromolecules (by a factor of ~20) compared to the case of non-modified or EG modified PMAcOD, emphasizing the importance of PEG tails in NP hydrophilization. The NPs coated with PMAcOD modified with 60% (towards all –MAcOD- units) of the 5,000 PEG tails bear a significant negative charge and display good stability in buffers. Such NPs can be useful as magnetic cores for virus-like particle formation. PMID:21221425
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Shrivastava, Preeti; Naoghare, Pravin K; Gandhi, Deepa; Devi, S Saravana; Krishnamurthi, Kannan; Bafana, Amit; Kashyap, Sanjay M; Chakrabarti, Tapan
2017-08-01
Exposure to pre-concentrated inlet or outlet STP wastewater extracts at different concentrations (0.001% to 1%) induced dose-dependent toxicity in MCF-7 cells, whereas drinking water extracts did not induce cytotoxicity in cells treated. GC-MS analysis revealed the occurrence of xenobiotic compounds (Benzene, Phthalate, etc.) in inlet/outlet wastewater extracts. Cells exposed to inlet/outlet extract showed elevated levels of reactive oxygen species (ROS: inlet: 186.58%, p<0.05, outlet, 147.8%, p<0.01) and loss of mitochondrial membrane potential (Δψm: inlet, 74.91%, p<0.01; outlet, 86.70%, p<0.05) compared to the control. These concentrations induced DNA damage (Tail length: inlet: 34.4%, p<0.05, outlet, 26.7%, p<0.05) in treated cells compared to the control (Tail length: 7.5%). Cell cycle analysis displayed drastic reduction in the G1 phase in treated cells (inlet, G1:45.0%; outlet, G1:58.3%) compared to the control (G1:67.3%). Treated cells showed 45.18% and 28.0% apoptosis compared to the control (1.2%). Drinking water extracts did not show any significant alterations with respect to ROS, Δψm, DNA damage, cell cycle and apoptosis compared to the control. Genes involved in cell cycle and apoptosis were found to be differentially expressed in cells exposed to inlet/outlet extracts. Herein, we propose cell-based toxicity assays to evaluate the efficacies of wastewater treatment and recycling processes. Copyright © 2017 Elsevier Inc. All rights reserved.
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Multi-functional foot use during running in the zebra-tailed lizard (Callisaurus draconoides).
Li, Chen; Hsieh, S Tonia; Goldman, Daniel I
2012-09-15
A diversity of animals that run on solid, level, flat, non-slip surfaces appear to bounce on their legs; elastic elements in the limbs can store and return energy during each step. The mechanics and energetics of running in natural terrain, particularly on surfaces that can yield and flow under stress, is less understood. The zebra-tailed lizard (Callisaurus draconoides), a small desert generalist with a large, elongate, tendinous hind foot, runs rapidly across a variety of natural substrates. We use high-speed video to obtain detailed three-dimensional running kinematics on solid and granular surfaces to reveal how leg, foot and substrate mechanics contribute to its high locomotor performance. Running at ~10 body lengths s(-1) (~1 m s(-1)), the center of mass oscillates like a spring-mass system on both substrates, with only 15% reduction in stride length on the granular surface. On the solid surface, a strut-spring model of the hind limb reveals that the hind foot saves ~40% of the mechanical work needed per step, significant for the lizard's small size. On the granular surface, a penetration force model and hypothesized subsurface foot rotation indicates that the hind foot paddles through fluidized granular medium, and that the energy lost per step during irreversible deformation of the substrate does not differ from the reduction in the mechanical energy of the center of mass. The upper hind leg muscles must perform three times as much mechanical work on the granular surface as on the solid surface to compensate for the greater energy lost within the foot and to the substrate.
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Gaur, Nisha; Kukreja, Aayush; Yadav, Mahavir; Tiwari, Archana
2017-07-01
A study was conducted to access the phytoremediation potential of Coriandrum sativum for lead (Pb) and Arsenic (As). Metal tolerance index and pot experiment were conducted. Viable seeds were spread on filter paper and planted in soil placed in pots. The amount of Pb and As in control and in tailing soil was 0.27, 0.141, 1.77, and 0.35 ppm. The study was carried out in triplicates for a period of 4 weeks under natural conditions. The physico-chemical properties of soil were determined using the standard methods. Germination of seeds of Coriander sativum was inhibited more rigorously in filter paper as compared to soil medium. Shoot height and root length were significantly reduced in filter paper medium under Pb and As stress. These were inhibited by 33 and 40%, respectively, from the first to fourth weeks. Seedling growth was less affected in soil medium while greatly reduced in filter paper medium. Soil sustained almost equal stress in the fourth week as compared to the third week in filter paper medium. Shoot height was enormously affected by Pb and As compared to root length in filter paper medium, whereas slight inhibition of growth was observed in soil medium. Coriander sativum grown in pots was effective in removing Pb and As from control and tailing soils in comparison with seeds grown on filter paper. On this basis, it could be used in restoring soil polluted with Pb and As.
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Intermittent Granular Dynamics at a Seismogenic Plate Boundary.
Meroz, Yasmine; Meade, Brendan J
2017-09-29
Earthquakes at seismogenic plate boundaries are a response to the differential motions of tectonic blocks embedded within a geometrically complex network of branching and coalescing faults. Elastic strain is accumulated at a slow strain rate on the order of 10^{-15} s^{-1}, and released intermittently at intervals >100 yr, in the form of rapid (seconds to minutes) coseismic ruptures. The development of macroscopic models of quasistatic planar tectonic dynamics at these plate boundaries has remained challenging due to uncertainty with regard to the spatial and kinematic complexity of fault system behaviors. The characteristic length scale of kinematically distinct tectonic structures is particularly poorly constrained. Here, we analyze fluctuations in Global Positioning System observations of interseismic motion from the southern California plate boundary, identifying heavy-tailed scaling behavior. Namely, we show that, consistent with findings for slowly sheared granular media, the distribution of velocity fluctuations deviates from a Gaussian, exhibiting broad tails, and the correlation function decays as a stretched exponential. This suggests that the plate boundary can be understood as a densely packed granular medium, predicting a characteristic tectonic length scale of 91±20 km, here representing the characteristic size of tectonic blocks in the southern California fault network, and relating the characteristic duration and recurrence interval of earthquakes, with the observed sheared strain rate, and the nanosecond value for the crack tip evolution time scale. Within a granular description, fault and blocks systems may rapidly rearrange the distribution of forces within them, driving a mixture of transient and intermittent fault slip behaviors over tectonic time scales.
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Mantha, Sriteja; McDaniel, Jesse G.; Perroni, Dominic V.; ...
2016-12-27
Gemini surfactants comprise two single-tailed surfactants connected by a linker at or near the hydrophilic headgroup. They display a variety of water concentration-dependent lyotropic liquid crystal (LLC) morphologies that are sensitive to surfactant molecular structure, and na- ture of the headgroups and counterions. Recently, an interesting dependence of the aqueous phase behavior on the length of the linker has been discovered; odd-numbered linker length surfactants exhibit characteristically different phase diagrams than even-numbered linker sur- factants. In this work, we investigate this “odd/even effect” using computer simulations, focusing on experimentally studied gemini dicarboxylates with Na + counterions, 7 non-terminal carbon atomsmore » in the tails, and either 3, 4, 5, or 6 carbon atoms in the linker (denoted Na-73, Na-74, Na-75, and Na-76 respectively). We find that the relative electrostatic repulsion be- tween headgroups in the different morphologies is correlated with qualitative features of the experimental phase diagrams, predicting destabilization of hexagonal phases as the cylinders pack close together at low water content. Significant differences in the relative headgroup ori- entations of Na-74 and Na-76 compared to Na-73 and Na-75 surfactants lead to differences in linker-linker packing, and long-range headgroup/headgroup electrostatic repulsion, which affects the delicate electrostatic balance between hexagonal and gyroid phases. Finally, much of the fundamental insight presented in this work is enabled by the ability to computationally construct and analyze metastable phases that are not observable in experiments.« less
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1,2,4-oxadiazole-based bent-core liquid crystals with cybotactic nematic phases.
Shanker, Govindaswamy; Prehm, Marko; Nagaraj, Mamatha; Vij, Jagdish K; Weyland, Marvin; Eremin, Alexey; Tschierske, Carsten
2014-05-19
Several series of bent-core mesogens derived from 3,5-diphenyl-1,2,4-oxadiazole with or without lateral groups and with different length terminal chains at both ends, and polycatenar molecules with three to six alkoxy chains are synthesized and their mesomorphic behaviour is investigated by polarizing microscopy, differential scanning calorimetry, X-ray diffraction (XRD), dielectric, electro-optical and second-harmonic generation (SHG) experiments. Most compounds exhibit broad regions of skewed cybotactic nematic (NcybC ) and tilted smectic (SmC) phases with a strong tilt of the aromatic cores (up to 63°), but non-tilted SmA and NcybA phases are also observed for a compound that has only one terminal chain. The XRD patterns of the nematic phases of most of the compounds investigated indicate a 2D periodicity with short correlation length in the magnetically aligned samples. This is of importance for the general interpretation of the small-angle XRD splitting patterns typically observed for aligned samples of bent-core nematic phases. In most nematic phases one current peak is observed in the half period of an applied electric field, though no coherent signal is found in the SHG experiments. Based on additional electro-optical and dielectric results, the nematic phases are considered to be cybotactic nematic phases with local polar order, and show a dielectric reorientation of the polar domains. Only chiral nematic phases (NcybC *), but not blue phases, are obtained for compounds with one or two chiral (3S)-3,7-dimethyloctyloxy tail(s). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Intermittent Granular Dynamics at a Seismogenic Plate Boundary
NASA Astrophysics Data System (ADS)
Meroz, Yasmine; Meade, Brendan J.
2017-09-01
Earthquakes at seismogenic plate boundaries are a response to the differential motions of tectonic blocks embedded within a geometrically complex network of branching and coalescing faults. Elastic strain is accumulated at a slow strain rate on the order of 10-15 s-1 , and released intermittently at intervals >100 yr , in the form of rapid (seconds to minutes) coseismic ruptures. The development of macroscopic models of quasistatic planar tectonic dynamics at these plate boundaries has remained challenging due to uncertainty with regard to the spatial and kinematic complexity of fault system behaviors. The characteristic length scale of kinematically distinct tectonic structures is particularly poorly constrained. Here, we analyze fluctuations in Global Positioning System observations of interseismic motion from the southern California plate boundary, identifying heavy-tailed scaling behavior. Namely, we show that, consistent with findings for slowly sheared granular media, the distribution of velocity fluctuations deviates from a Gaussian, exhibiting broad tails, and the correlation function decays as a stretched exponential. This suggests that the plate boundary can be understood as a densely packed granular medium, predicting a characteristic tectonic length scale of 91 ±20 km , here representing the characteristic size of tectonic blocks in the southern California fault network, and relating the characteristic duration and recurrence interval of earthquakes, with the observed sheared strain rate, and the nanosecond value for the crack tip evolution time scale. Within a granular description, fault and blocks systems may rapidly rearrange the distribution of forces within them, driving a mixture of transient and intermittent fault slip behaviors over tectonic time scales.
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de la Barre, Anne-Elisabeth; Angelov, Dimitri; Molla, Annie; Dimitrov, Stefan
2001-01-01
We have studied the role of individual histone N-termini and the phosphorylation of histone H3 in chromosome condensation. Nucleosomes, reconstituted with histone octamers containing different combinations of recombinant full-length and tailless histones, were used as competitors for chromosome assembly in Xenopus egg extracts. Nucleosomes reconstituted with intact octamers inhibited chromosome condensation as efficiently as the native ones, while tailless nucleosomes were unable to affect this process. Importantly, the addition to the extract of particles containing only intact histone H2B strongly interfered with chromosome formation while such an effect was not observed with particles lacking the N-terminal tail of H2B. This demonstrates that the inhibition effect observed in the presence of competitor nucleosomes is mainly due to the N-terminus of this histone, which, therefore, is essential for chromosome condensation. Nucleosomes in which all histones but H3 were tailless did not impede chromosome formation. In addition, when competitor nucleosome particles were reconstituted with full-length H2A, H2B and H4 and histone H3 mutated at the phosphorylable serine 10 or serine 28, their inhibiting efficiency was identical to that of the native particles. Hence, the tail of H3, whether intact or phosphorylated, is not important for chromosome condensation. A novel hypothesis, termed ‘the ready production label’ was suggested to explain the role of histone H3 phosphorylation during cell division. PMID:11707409
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Biomonitoring of Toxic Effects of Pesticides in Occupationally Exposed Individuals.
Arshad, Muhammad; Siddiqa, Maryam; Rashid, Saddaf; Hashmi, Imran; Awan, Muhammad Ali; Ali, Muhammad Arif
2016-06-01
Workers in pesticide manufacturing industries are constantly exposed to pesticides. Genetic biomonitoring provides an early identification of potential cancer and genetic diseases in exposed populations. The objectives of this biomonitoring study were to assess DNA damage through comet assay in blood samples collected from industry workers and compare these results with those of classical analytical techniques used for complete blood count analysis. Samples from controls (n = 20) and exposed workers (n = 38) from an industrial area in Multan, Pakistan, were subjected to various tests. Malathion residues in blood samples were measured by gas chromatography. The exposed workers who were employed in the pesticide manufacturing industry for a longer period (i.e., 13-25 years) had significantly higher DNA tail length (7.04 μm) than the controls (0.94 μm). Workers in the exposed group also had higher white blood cell and red blood cell counts, and lower levels of mean corpuscular hemoglobin (MCH), MCH concentration, and mean corpuscular volume in comparison with normal levels for these parameters. Malathion was not detected in the control group. However, in the exposed group, 72% of whole blood samples had malathion with a mean value of 0.14 mg/L (range 0.01-0.31 mg/L). We found a strong correlation (R (2) = 0.91) between DNA damage in terms of tail length and malathion concentration in blood. Intensive efforts and trainings are thus required to build awareness about safety practices and to change industrial workers' attitude to prevent harmful environmental and anthropogenic effects.
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Locus-specific oligonucleotide probes increase the usefulness of inter-Alu polymorphisms
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jarnik, M.; Tang, J.Q.; Korab-Laskowska, M.
1994-09-01
Most of the mapping approaches are based on single-locus codominant markers of known location. Their multiplex ratio, defined as the number of loci that can be simultaneously tested, is typically one. An increased multiplex ratio was obtained by typing anonymous polymorphisms using PCR primers anchored in ubiquitous Alu-repeats. These so called alumorphs are revealed by inter-Alu-PCR and seen as the presence or absence of an amplified band of a given length. We decided to map alumorphs and to develop locus-specific oligonucleotide (LSO) probes to facilitate their use and transfer among different laboratories. We studied the segregation of alumorphs in eightmore » CEPH families, using two distinct Alu-primers, both directing PCR between the repeats in a tail-to-tail orientation. The segregating bands were assigned to chromosomal locations by two-point linkage analysis with CEPH markers (V6.0). They were excised from dried gels, reamplified, cloned and sequenced. The resulting LSOs were used as hybridization probes (i) to confirm chromosomal assignments in a human/hamster somatic cell hybrid panel, and (ii) to group certain allelic length variants, originally coded as separate dominant markres, into more informative codominant loci. These codominants were then placed by multipoint analysis on a microsatellite Genethon map. Finally, the LSO probes were used as polymorphic STSs, to identify by hybridization the corresponding markers among products of inter-Alu-PCR. The use of LSOs converts alumorphs into a system of non-anonymous, often multiallelic codominant markes which can be simultaneously typed, thus achieving the goal of high multiplex ratio.« less
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Pichorim, M; Monteiro-Filho, E L A
2008-11-01
Many Apodidae, including Streptoprocne biscutata (Sclater, 1866), drop eggs from their nests during incubation. This is interpreted as nest site competition or accident. We provide evidence that egg ejection is deliberate and that this behaviour controls the brood size. Brood sizes were manipulated and nestling growth was measured to test the hypothesis that pairs can regulate brood size during incubation based on current ability to rear nestlings. Natural (control) broods with one, two and three nestlings, and manipulated (experimental) broods reduced to one and increased to two and three young were monitored. Growth rates were measured based on weight, and wing, tail and tarsus lengths of natural and manipulated broods. We compared the slopes of each measure's regression lines of the nestlings of each brood size by t-test. Nestling growth of control nests was similar and relatively little associated with brood size. In broods reduced to one nestling, weight, wing and tail had greater growth rates, and in broods increased to three nestlings growth rates were lower. Weight was most, and tarsus length least influenced by brood size. In general, nestling growth of manipulated nests was inversely proportional to brood size. The results suggest that pairs with larger clutches are in better physical conditions than others. Thus, in experimental broods, pairs are over or under-loaded because feeding activities increase or decrease and these changes affect the growth rate of the nestlings. The present study suggests that egg ejection can control brood size. This behaviour is probably stimulated by physical changes in the adult birds during incubation.
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DNA damage in outdoor workers occupationally exposed to environmental air pollutants
Tovalin, H; Valverde, M; Morandi, M T; Blanco, S; Whitehead, L; Rojas, E
2006-01-01
Background Health concerns about the exposure to genotoxic and carcinogenic agents in the air are particularly significant for outdoor workers in less developed countries. Aims To investigate the association between personal exposure to a group of air pollutants and severity of DNA damage in outdoor workers from two Mexican cities. Methods DNA damage (Comet assay) and personal exposure to volatile organic compounds, PM2.5, and ozone were investigated in 55 outdoor and indoor workers from México City and Puebla. Results In México City, outdoor workers had greater DNA damage, reflected by a longer tail length, than indoor workers (median 46.8 v 30.1 μm), and a greater percentage of highly damaged cells (cells with tail length ⩾41 μm); in Puebla, outdoor and indoor workers had similar DNA damage. There were more alkali labile sites in outdoor than indoor workers. The DNA damage magnitude was positively correlated with PM2.5 and ozone exposure. Outdoor and indoor workers with ⩾60% of highly damaged cells (highly damaged workers) had significantly higher exposures to PM2.5, ozone, and some volatile organic compounds. The main factors associated with the highly damaged workers were ozone, PM2.5, and 1‐ethyl‐2‐methyl benzene exposure. Conclusions With this approach, the effects of some air pollutants could be correlated with biological endpoints from the Comet assay. It is suggested that the use of personal exposure assessment and biological endpoints evaluation could be an important tool to generate a more precise assessment of the associated potential health risks. PMID:16556741
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Gajski, Goran; Garaj-Vrhovac, Vera
2008-01-01
This study investigated the genotoxic potential of atorvastatin on human lymphocytes using comet assay, structural chromosome aberrations (CA) and sister-chromatid exchange (SCE) analysis. Lymphocyte cultures were treated with a single drug at a concentration of 30.21 ng/mL. For comet assay, cells exposed to atorvastatin for 24 h, 48 h and 72 h were embedded in agarose slides, lysed with alkaline lysis solution and exposed to an electric field. DNA migrated within the agarose and formed comets whose length depends on the amount of DNA damage. For analysis of structural CA, cells were grown on medium for 48 h and for SCE analysis for 72 h. Structural CA did not induce significant damage to the genome, although a higher CA frequency was observed in cells treated with atorvastatin for 3 h, 20 h and 48 h than in control samples. Results of the SCE analysis did show statistically significant differences in the mean SCE number between atorvastatin-exposed and control human lymphocytes and between different exposure times. Comet assay also showed increased DNA damage caused in atorvastatin-exposed human lymphocytes than in corresponding control cells for exposure times of 24 h, 48 h and 72 h for the tail length and for 72 h for the tail moment. Results obtained in this study point to the significance of biological indicators providing information on the primary genome damage after long-term exposure, which can help to establish drug therapeutic concentrations that do not put patients with high blood cholesterol to a greater treatment-related risk.
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Wei, Chang-Na; Zhou, Qing-He; Wang, Li-Zhong
2017-01-01
Abstract Currently, there is no consensus on how to determine the optimal dose of intrathecal bupivacaine for an individual undergoing an elective cesarean section. In this study, we developed a regression equation between intrathecal 0.5% hyperbaric bupivacaine volume and abdominal girth and vertebral column length, to determine a suitable block level (T5) for elective cesarean section patients. In phase I, we analyzed 374 parturients undergoing an elective cesarean section that received a suitable dose of intrathecal 0.5% hyperbaric bupivacaine after a combined spinal-epidural (CSE) was performed at the L3/4 interspace. Parturients with T5 blockade to pinprick were selected for establishing the regression equation between 0.5% hyperbaric bupivacaine volume and vertebral column length and abdominal girth. Six parturient and neonatal variables, intrathecal 0.5% hyperbaric bupivacaine volume, and spinal anesthesia spread were recorded. Bivariate line correlation analyses, multiple line regression analyses, and 2-tailed t tests or chi-square test were performed, as appropriate. In phase II, another 200 parturients with CSE for elective cesarean section were enrolled to verify the accuracy of the regression equation. In phase I, a total of 143 parturients were selected to establish the following regression equation: YT5 = 0.074X1 − 0.022X2 − 0.017 (YT5 = 0.5% hyperbaric bupivacaine volume for T5 block level; X1 = vertebral column length; and X2 = abdominal girth). In phase II, a total of 189 participants were enrolled in the study to verify the accuracy of the regression equation, and 155 parturients with T5 blockade were deemed eligible, which accounted for 82.01% of all participants. This study evaluated parturients with T5 blockade to pinprick after a CSE for elective cesarean section to establish a regression equation between parturient vertebral column length and abdominal girth and 0.5% hyperbaric intrathecal bupivacaine volume. This equation can accurately predict the suitable intrathecal hyperbaric bupivacaine dose for elective cesarean section. PMID:28834913
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Wei, Chang-Na; Zhou, Qing-He; Wang, Li-Zhong
2017-08-01
Currently, there is no consensus on how to determine the optimal dose of intrathecal bupivacaine for an individual undergoing an elective cesarean section. In this study, we developed a regression equation between intrathecal 0.5% hyperbaric bupivacaine volume and abdominal girth and vertebral column length, to determine a suitable block level (T5) for elective cesarean section patients.In phase I, we analyzed 374 parturients undergoing an elective cesarean section that received a suitable dose of intrathecal 0.5% hyperbaric bupivacaine after a combined spinal-epidural (CSE) was performed at the L3/4 interspace. Parturients with T5 blockade to pinprick were selected for establishing the regression equation between 0.5% hyperbaric bupivacaine volume and vertebral column length and abdominal girth. Six parturient and neonatal variables, intrathecal 0.5% hyperbaric bupivacaine volume, and spinal anesthesia spread were recorded. Bivariate line correlation analyses, multiple line regression analyses, and 2-tailed t tests or chi-square test were performed, as appropriate. In phase II, another 200 parturients with CSE for elective cesarean section were enrolled to verify the accuracy of the regression equation.In phase I, a total of 143 parturients were selected to establish the following regression equation: YT5 = 0.074X1 - 0.022X2 - 0.017 (YT5 = 0.5% hyperbaric bupivacaine volume for T5 block level; X1 = vertebral column length; and X2 = abdominal girth). In phase II, a total of 189 participants were enrolled in the study to verify the accuracy of the regression equation, and 155 parturients with T5 blockade were deemed eligible, which accounted for 82.01% of all participants.This study evaluated parturients with T5 blockade to pinprick after a CSE for elective cesarean section to establish a regression equation between parturient vertebral column length and abdominal girth and 0.5% hyperbaric intrathecal bupivacaine volume. This equation can accurately predict the suitable intrathecal hyperbaric bupivacaine dose for elective cesarean section.
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Tail thrust of bluefish Pomatomus saltatrix at different buoyancies, speeds, and swimming angles.
Ogilvy, C S; DuBois, A B
1982-06-01
1. The tail thrust of bluefish Pomatomus saltatrix was measured using a body accelerometer at different water speeds, buoyancies, and angles of water flow to determine the contribution of tail thrust in overcoming parasitic drag, induced drag, and weight directed along the track. The lengths and weights of the fish averaged 0.52 m and 1.50 kg respectively. 2. The tail thrust overcoming parasitic drag in Newtons, as measured during neutral buoyancy, was: 0.51 x speed + 0.15, with a standard error of estimate of 0.09 N. 3. When buoyancy was altered by the introduction or removal of air from a balloon implanted in the swim bladder, the tail thrust was altered by an amount of the same order as the value calculated for the induced drag of the pectoral fins. 4. The component of weight directed backward along the track was the weight in water multiplied by the sine of the angle of the swimming tunnel relative to horizontal. When this force was added to the calculated induced drag and tail thrust measured at neutral buoyancy, the rearward force equal to the tail thrust, at 45 ml negative buoyancy, 0.5 m s-1, and 15 degrees head up, was 0.12 N due to weight + 0.05 N due to induced drag + 0.40 N due to parasitic drag = 0.57 N total rearward force. 5. The conditions required for gliding were not achieved in our bluefish because the drag exceeded the component of the weight in water directed forward along the track at speeds above the stalling speed of the pectoral fins.
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[Effect of severe burn on growth and development and the level of growth hormone in mice].
Wang, Fei; Qiu, Lin; Liu, Cuiping; Tian, Xiaofei; Xiao, Jun
2014-02-01
To analyze the changes in body growth, learning and memory capabilities, exercise capacity, and the level of growth hormone (GH) in mice suffering from severe burn. One hundred and four healthy BALB/c mice aged from 3 to 4 weeks were divided into normal control group (NC, without treatment) , 7 s burn group (inflicted with 20%TBSA deep partial-thickness burn on the back), 10 s burn group (inflicted with 20%TBSA full-thickness burn on the back), and negative control group (simulating the treatment of two burn groups without injury) according to the random number table, with 26 mice in each group. The body weight, body length, and tail length of 8 mice in each group were measured before burn. Respectively 6 mice of two burn groups were sacrificed on post burn day (PBD) 1, 3, and 7 for determination of serum level of GH with enzyme-linked immunosorbent assay kit. The remaining 8 mice in each of the two burn groups were raised to adulthood. The body weight, body length, and tail length were measured on PBD 62, and the increased percentages of body weight, body length, and tail length were calculated. Morris water maze tests, including escape latency on PBD 66, 67, and 68, frequency of stepping over the platform location and proportion of staying time in the target quadrant on PBD 69, were used to examine the learning and memory capabilities. The time of loaded swimming and the time of pole-climbing on PBD 70 were used to assess the exercise capacity. Above-mentioned indexes were also determined in the two control groups at the same time points. Data were processed with one-way analysis of variance; Welch test was applied when equal variance was not assumed; independent samples t test was applied for paired comparison. (1) The level of GH of mice in 7 s burn group on PBD 1 [(3 021 ± 506) pg/mL] was lower than that of group NC [(3 728 ± 412) pg/mL, t = 2.656, P < 0.05], while on PBD 3 and 7 [(3 098 ± 503) , (3 199 ± 275) pg/mL] they were close to those of group NC [(3 872 ± 785), (3 301 ± 600) pg/mL, with t values respectively 2.033 and 0.379, P values all above 0.05]. The levels of GH of mice in 10 s burn group on PBD 1, 3, and 7 were respectively (2 859 ± 447), (2 707 ± 151) , and (2 666 ± 222) pg/mL, which were lower than those of group NC (with t values respectively 3.504, 3.571, 2.429, P < 0.05 or P < 0.01). (2) The increased percentage of body weight, body length, and tail length of mice in group NC, 7 s burn group, and 10 s burn group were respectively (155 ± 22) %, (46 ± 6) %, (63 ± 10)%; (112 ± 57) %, (32 ± 12) %, (40 ± 15) %; (106 ± 36) %, (30 ± 8) %, (32 ± 7) %. The increased percentage of body weight of mice in 7 s burn group was close to that in group NC (t = 1.997, P > 0.05), while the increased percentages of other indexes of mice in the two burn groups were lower than those in group NC (with t values from 3.092 to 6.910, P values all below 0.01). (3) The escape latency values of mice in 10 s burn group on PBD 67 and 68 were respectively (33 ± 12), (33 ± 11) s, which were longer than those of group NC [(20 ± 8), (20 ± 7) s, with t values respectively 2.421 and 2.692, P values all below 0.05]. The frequency of stepping over the platform location of mice in 10 s burn group [(1.6 ± 1.8) times] was close to that of group NC [(3.2 ± 1.5) times, t = 1.989, P > 0.05]. The proportion of retention time in the target quadrant of mice in 10 s burn group [ (28 ± 7) %] was shorter than that of group NC[(48 ± 16)%, t = 3.076, P < 0.01]. The escape latency of mice in 7 s burn group on PBD 67 [(30 ± 7) s] was longer than that of group NC (t = 2.659, P < 0.05). The frequency of stepping over the platform location and the proportion of retention time in the target quadrant of mice in 7 s burn group [(2.0 ± 1.1) times, (36 ± 11) %, respectively] were close to those of group NC (with t values respectively 1.930, 1.670, P values all above 0.05). (4) The time of pole-climbing [(30 ± 11) s] and the time of loaded swimming [(38 ± 39) min] of mice in 10 s burn group were shorter than those of group NC [(47 ± 11) s, (122 ± 74) min, with t values respectively 3.108, 2.868, P < 0.05 or P < 0.01]. The time of loaded swimming of mice in 7 s burn group [(47 ± 12) min] was shorter than that of group NC (t = 2.855, P < 0.05), while the time of pole-climbing [(33 ± 14) s] was close to that of group NC (t = 2.044, P > 0.05). For mice, severe burn can delay body growth, decrease the learning and memory capabilities, decrease exercise capacities, and reduce the serum level of GH.
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Park, Chan Jin; Song, Sang Ha; Kim, Dae Han; Gye, Myung Chan
2017-01-01
The developmental toxicity of nickel was examined in the embryos of Bombina orientalis, a common amphibian in Korea. Based on a standard frog embryo teratogenesis assay, the LC 50 and EC 50 for malformation of nickel after 168h of treatment were 33.8μM and 5.4μM, respectively. At a lethal concentration (100μM), nickel treatment decreased the space between gill filaments and caused epithelial swelling and abnormal fusion of gill filaments. These findings suggest that nickel affects the functional development of gills, leading to embryonic death. At sublethal concentrations (1-10μM), nickel produced multiple embryonic abnormalities, including bent tail and tail dysplasia. At 10μM, nickel significantly decreased tail length and tail muscle fiber density in tadpoles, indicating inhibition of myogenic differentiation. Before hatching, the pre-muscular response to muscular response stages (stages 26-31) were the most sensitive period to nickel with respect to tail muscle development. During these stages, MyoD mRNA was upregulated, whereas myogenic regulatory factor 4 mRNA was downregulated by 0.1μM nickel. Calcium-dependent kinase activities in muscular response stage embryos were significantly decreased by nickel, whereas these activities were restored by exogenous calcium. In tadpoles, 10μM nickel significantly decreased the expression of the myosin heavy chain and the 12/101 muscle marker protein in the tail. Expression was restored by exogenous calcium. Our results indicate that nickel affects muscle development by disrupting calcium-dependent myogenesis in developing B. orientalis embryos. Copyright © 2016 Elsevier B.V. All rights reserved.
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Prehensile and non-prehensile tails among syngnathid fishes: what's the difference?
Neutens, Céline; de Dobbelaer, Bart; Claes, Peter; Adriaens, Dominique
2017-02-01
All syngnathid fishes are characterized by a tail with a vertebral column that is surrounded by dermal Plates - four per vertebra. Seahorses and pipehorses have prehensile tails, a unique characteristic among teleosts that allows them to grasp and hold onto substrates. Pipefishes, in contrast, possess a more rigid tail. Previous research (Neutens et al., 2014) showed a wide range of variation within the skeletal morphology of different members in the syngnathid family. The goal of this study is to explore whether the diversity in the three-dimensional (3D) shape of different tail types reflects grasping performance, and to what degree grasping tails occupy a different and more constrained diversity. For this, a 3D morphometrical analysis based on surfaces was performed. Four different analyses were performed on the tail skeleton of nine species exhibiting different levels of tail grasping capacities (four pipehorse, three seahorse, one pipefish and one seadragon species) to examine the intra-individual variation across the anteroposterior and dorso-ventral axis. In the two interspecific analyses, all vertebrae and all dermal plates were mutually compared. Overall, intra-individual variation was larger in species with a prehensile tail. The analysis on the vertebrae showed differences in the length and orientation of the hemal spine as well as the inclination angle between the anterior and posterior surface of the vertebral body. This was observed at an intra-individual level across the anteroposterior axis in prehensile species and at an inter-individual level between prehensile and non-prehensile species. Across the anteroposterior axis in prehensile tails, the overall shape of the plates changes from rectangular at the anterior end to square at the posterior end. Across the dorso-ventral axis, the ventral dermal plates carry a significantly longer caudal spine than the dorsal ones in all prehensile-tailed species. It can therefore be concluded that prehensile tails exhibit a larger anteroposterior and dorso-ventral shape variation than non-prehensile ones. However, the hypothesis that there is a more constrained shape variation among prehensile species compared to non-prehensile ones had to be rejected. Copyright © 2016 Elsevier GmbH. All rights reserved.
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Zhang, Weisheng; Lin, Jiang; Wang, Shaowu; Lv, Peng; Wang, Lili; Liu, Hao; Chen, Caizhong; Zeng, Mengsu
2014-01-01
This study was aimed to evaluate the accuracy of "True Fast Imaging with Steady-State Precession" (TrueFISP) MR angiography (MRA) for diagnosis of renal arterial stenosis (RAS) in hypertensive patients. Twenty-two patients underwent both TrueFISP MRA and contrast-enhanced MRA (CE-MRA) on a 1.5-T MR imager. Volume of main renal arteries, length of maximal visible renal arteries, number of visualized branches, stenotic grade, and subjective quality were compared. Paired 2-tailed Student t test and Wilcoxon signed rank test were applied to evaluate the significance of these variables. Volume of main renal arteries, length of maximal visible renal arteries, and number of branches indicated no significant difference between the 2 techniques (P > 0.05). Stenotic degree of 10 RAS was greater on CE-MRA than on TrueFISP MRA. Qualitative scores from TrueFISP MRA were higher than those from CE-MRA (P < 0.05). TrueFISP MRA is a reliable and accurate method for evaluating RAS.
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Pfeiffer, Tanya; Ruppert, Thomas; Schaal, Heiner; Bosch, Valerie
2013-06-20
Employing antibodies against the cytoplasmic tail of the HIV-1 glycoprotein (Env-CT), in addition to gp160/gp41, we have identified several novel small Env proteins (<25kD) in HIV-1 transfected and infected cells. Mass spectrometric and mutational analyses show that two mechanisms contribute to their generation. Thus the protein, designated Tr-Env-CT (for truncated Env-CT), consists of the C-terminal 139 amino acids (aa) of Env (aa 718-856) with the N-terminal Q718 modified to pyroglutamic acid. It is likely derived from full-length Env protein by proteolytic processing. A further heterogeneous set of slightly larger proteins, termed Env-CT* species, are rather derived from spliced mRNAs containing only those Env C-terminal residues (aa 719-856) which overlap with the second tat and rev coding exons. They are N-terminally extended in the same reading frame. It is conceivable that essential Env-CT functions may be fulfilled by these novel species rather than by the full-length glycoprotein itself. Copyright © 2013 Elsevier Inc. All rights reserved.
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Li, Liang; Guo, Yan-Ning; Li, Jian; Zhang, Lu-Ping
2014-12-01
Ophidascaris wangi sp. n. collected from the king rat snake Elaphe carinata (Günther) (Serpentes: Colubridae) in China is described using both light and scanning electron microscopy. The new species differs from its congeners in the presence of narrow lateral alae originating a short distance posterior to the base of the ventrolateral lips, its relatively long oesophagus (3.57-4.54 mm long, representing 6.6-7.6% of body length), its short spicules (1.89-2.14 mm long, representing 3.9-4.3% of body length), the number and arrangement of caudal papillae (49-57 pairs in total, arranged as follows: 43-51 pairs precloacal, 2 pairs joined paracloacal and 4 pairs postcloacal), the presence of a particular papilliform medioventral, postcloacal ornamentation and the morphology of the eggs and tip of the female tail. In addition, Ophidascaris najae (Gedoelst, 1916), collected from the king cobra Ophiophagus hannah Cantor (Serpentes: Elapidae) in China, is also redescribed. The morphology of the cervical papillae, labial denticles and phasmids of the female is described for the first time.
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Kumar, Vikash; Chatterjee, Amrita; Kumar, Nupur; Ganguly, Anasuya; Chakraborty, Indranil; Banerjee, Mainak
2014-10-09
Four new D-glucose derived m-s-m type gemini surfactants with variable spacer and tail length have been synthesized by a simple and efficient synthetic methodology utilizing the free C-3 hydroxy group of diisopropylidene glucose. The synthetic route to these gemini surfactants with a quaternary ammonium group as polar head group involves a sequence of simple reactions including alkylation, imine formation, quaternization of amine etc. The surface properties of the new geminis were evaluated by surface tension and conductivity measurements. These gemini surfactants showed low cytotoxicity by MTT assay on HeLa cell line. The DNA binding capabilities of these surfactants were determined by agarose gel electrophoresis, fluorescence titration, and DLS experiments. The preliminary studies by agarose gel electrophoresis indicated chain length dependent DNA binding abilities, further supported by ethidium bromide exclusion experiments. Two of the D-glucose derived gemini surfactants showed effective binding with pET-28a plasmid DNA (pDNA) at relatively low N/P ratio (i.e., cationic nitrogen/DNA phosphate molar ratio). Copyright © 2014 Elsevier Ltd. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Jiang, Deen; Dass, Amala; Tschumper, Gregory
2011-01-01
A systematic study of cross-linking chemistry of the Au{sub 25}(SR){sub 18} nanomolecule by dithiols of varying chain length, HS-(CH2)n-SH where n = 2, 3, 4, 5, and 6, is presented here. Monothiolated Au{sub 25} has six [RSAuSRAuSR] staple motifs on its surface, and MALDI mass spectrometry data of the ligand exchanged clusters show that propane (C3) and butane (C4) dithiols have ideal chain lengths for interstaple cross-linking and that up to six C3 or C4 dithiols can be facilely exchanged onto the cluster surface. Propanedithiol predominately exchanges with two monothiols at a time, making cross-linking bridges, while butanedithiol can exchangemore » with either one or two monothiols at a time. The extent of cross-linking can be controlled by the Au{sub 25}(SR){sub 18} to dithiol ratio, the reaction time of ligand exchange, or the addition of a hydrophobic tail to the dithiol. MALDI MS suggests that during ethane (C2) dithiol exchange, two ethanedithiols become connected by a disulfide bond; this result is supported by density functional theory (DFT) prediction of the optimal chain length for the intrastaple coupling. Both optical absorption spectroscopy and DFT computations show that the electronic structure of the Au{sub 25} nanomolecule retains its main features after exchange of up to eight monothiol ligands.« less
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Radio tag retention and tag-related mortality among adult sockeye salmon
Ramstad, Kristina M.; Woody, Carol Ann
2003-01-01
Tag retention and tag-related mortality are concerns for any tagging study but are rarely estimated. We assessed retention and mortality rates for esophageal radio tag implants in adult sockeye salmon Oncorhynchus nerka. Migrating sockeye salmon captured at the outlet of Lake Clark, Alaska, were implanted with one of four different radio tags (14.5 × 43 mm (diameter × length), 14.5 × 49 mm, 16 × 46 mm, and 19 × 51 mm). Fish were observed for 15 to 35 d after tagging to determine retention and mortality rates. The overall tag retention rate was high (0.98; 95% confidence interval (CI), 0.92-1.00; minimum, 33 d), with one loss of a 19-mm × 51- mm tag. Mortality of tagged sockeye salmon (0.02; 95% CI, 0-0.08) was similar to that of untagged controls (0.03 (0-0.15)). Sockeye salmon with body lengths (mid-eye to tail fork) of 585-649 mm retained tags as large as 19 × 51 mm and those with body lengths of 499-628 mm retained tags as small as 14.5 × 43 mm for a minimum of 33 d with no increase in mortality. The tags used in this study represent a suite of radio tags that vary in size, operational life, and cost but that are effective in tracking adult anadromous salmon with little tag loss or increase in fish mortality.
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Glowska, Eliza
2015-12-01
A new quill mite species Stibarokris mariasi sp. nov. (Acariformes: Syringophilidae) is described from the Wedge-tailed Shearwater Puffinus pacificus (Gmelin) (Procellariiformes: Procellariidae) from Johnston Atoll. Females of S. mariasi sp. nov. differ from most similar species S. phoeniconaias Skoracki and OConnor, 2010 by the longitudinal branch of the peritremes consisting of 11-14 chambers (vs 15-17 chambers in S. phoeniconaias), the movable cheliceral digit 145 long (vs 170), setal bases c1 situated distinctly anterior to the level of setae se (vs setal bases c1 and se situated at the same transverse level), the propodonotal shield punctate on the whole surface (vs propodonotal shield punctate at the lateral margins), the small, balloonlike hysteronotal shield, bearing bases of setae d1 and densely punctate on the whole surface (vs hysteronotal shield bearing setal bases d1 and e2 and punctate at the anterior part), the pseudanal setae ps1 1.8 times longer than setae ps2 (vs setae ps1 and ps2 subequal in length), subequal lengths of setae h1 and f1 (vs setae h1 twice longer than f1) and the lengths of setae ag1, ag2, and ag3 145-170, 105-125, 120-165, respectively (vs ag1, ag2 and ag3 245-285, 245-270, 330-340, respectively). A key to all known species of the genus Stibarokris Kethley, 1970 is proposed.
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Altered cellular kinetics in growth plate according to alterations in weight bearing.
Park, Hoon; Kong, Sun Young; Kim, Hyun Woo; Yang, Ick Hwan
2012-05-01
To examine the effects of change in weight bearing on the growth plate metabolism, a simulated animal model of weightlessness was introduced and the chondrocytes' cellular kinetics was evaluated. Unloading condition on the hind-limb of Sprague-Dawley rats was created by fixing a tail and lifting the hind-limb. Six rats aged 6 weeks old were assigned to each group of unloading, reloading, and control groups of unloading or reloading. Unloading was maintained for three weeks, and then reloading was applied for another one week thereafter. Histomorphometry for the assessment of vertical length of the growth plate, 5-bromo-2'-deoxyuridin immunohistochemistry for cellular kinetics, and biotin nick end labeling transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay for chondrocytes apoptosis in the growth plate were performed. The vertical length of the growth plate and the proliferative potential of chondrocytes were decreased in the unloading group compared to those of control groups. Inter-group differences were more significant in the proliferative and hypertrophic zones. Reloading increased the length of growth plate and proliferative potential of chondrocytes. However, apoptotic changes in the growth plate were not affected by the alterations of weight bearing. Alterations in the weight bearing induced changes in the chondrocytic proliferative potential of the growth plate, however, had no effects on the apoptosis. This may explain why non-weight bearing in various clinical situations hampers normal longitudinal bone growth. Further studies on the factors for reversibility of chondrocytic proliferation upon variable mechanical stresses are needed.
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Andrewartha, Sarah J; Mitchell, Nicola J; Frappell, Peter B
2010-01-01
Many lineages of parthenogenetic organisms have persisted through significant environmental change despite the constraints imposed by their fixed genotype and limited evolutionary potential. The ability of parthenogens to occur sympatrically with sexual relatives may in part be due to phenotypic plasticity in their responses to their environment, especially with respect to incubation temperature--a maternally selected trait. Here we measured the incubation temperatures selected by two lineages of triploid parthenogenic geckos in the Heteronotia binoei complex by allowing them to deposit clutches along a thermal gradient. The average nest temperature selected was 28.4 degrees C, with no significant differences between parthenogenic races or individual clones. To investigate the effect of nest-temperature variability on physiological and morphological traits, we incubated eggs from different races at one of four incubation regimes (32 degrees +/- 0 degrees, +/- 3 degrees , +/- 5 degrees , or +/- 9 degrees C). Embryos incubated at constant 32 degrees C developed faster than embryos reared under increasing extremes of diel temperature fluctuation (+/- 3 degrees , +/- 5 degrees C), and incubation at 32 degrees +/- 9 degrees C was unsuccessful. Incubation regime had no effect on the body size, preferred substrate temperature, or mass-specific .V(O2) of hatchlings. However, parthenogenic race had a significant effect on egg mass, tail length, snout-to-vent length, total length, and .V(O2) . We conclude that developmental traits are strongly influenced by clonal genotypes in this parthenogenic complex but are well buffered against fluctuations in incubation temperature.
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Deep Sequence Analysis of AgoshRNA Processing Reveals 3' A Addition and Trimming.
Harwig, Alex; Herrera-Carrillo, Elena; Jongejan, Aldo; van Kampen, Antonius Hubertus; Berkhout, Ben
2015-07-14
The RNA interference (RNAi) pathway, in which microprocessor and Dicer collaborate to process microRNAs (miRNA), was recently expanded by the description of alternative processing routes. In one of these noncanonical pathways, Dicer action is replaced by the Argonaute2 (Ago2) slicer function. It was recently shown that the stem-length of precursor-miRNA or short hairpin RNA (shRNA) molecules is a major determinant for Dicer versus Ago2 processing. Here we present the results of a deep sequence study on the processing of shRNAs with different stem length and a top G·U wobble base pair (bp). This analysis revealed some unexpected properties of these so-called AgoshRNA molecules that are processed by Ago2 instead of Dicer. First, we confirmed the gradual shift from Dicer to Ago2 processing upon shortening of the hairpin length. Second, hairpins with a stem larger than 19 base pair are inefficiently cleaved by Ago2 and we noticed a shift in the cleavage site. Third, the introduction of a top G·U bp in a regular shRNA can promote Ago2-cleavage, which coincides with a loss of Ago2-loading of the Dicer-cleaved 3' strand. Fourth, the Ago2-processed AgoshRNAs acquire a short 3' tail of 1-3 A-nucleotides (nt) and we present evidence that this product is subsequently trimmed by the poly(A)-specific ribonuclease (PARN).
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Deep Sequence Analysis of AgoshRNA Processing Reveals 3' A Addition and Trimming
Harwig, Alex; Herrera-Carrillo, Elena; Jongejan, Aldo; van Kampen, Antonius Hubertus; Berkhout, Ben
2015-01-01
The RNA interference (RNAi) pathway, in which microprocessor and Dicer collaborate to process microRNAs (miRNA), was recently expanded by the description of alternative processing routes. In one of these noncanonical pathways, Dicer action is replaced by the Argonaute2 (Ago2) slicer function. It was recently shown that the stem-length of precursor-miRNA or short hairpin RNA (shRNA) molecules is a major determinant for Dicer versus Ago2 processing. Here we present the results of a deep sequence study on the processing of shRNAs with different stem length and a top G·U wobble base pair (bp). This analysis revealed some unexpected properties of these so-called AgoshRNA molecules that are processed by Ago2 instead of Dicer. First, we confirmed the gradual shift from Dicer to Ago2 processing upon shortening of the hairpin length. Second, hairpins with a stem larger than 19 base pair are inefficiently cleaved by Ago2 and we noticed a shift in the cleavage site. Third, the introduction of a top G·U bp in a regular shRNA can promote Ago2-cleavage, which coincides with a loss of Ago2-loading of the Dicer-cleaved 3' strand. Fourth, the Ago2-processed AgoshRNAs acquire a short 3' tail of 1–3 A-nucleotides (nt) and we present evidence that this product is subsequently trimmed by the poly(A)-specific ribonuclease (PARN). PMID:26172504
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Coupling between the Dynamics of Water and Surfactants in Lyotropic Liquid Crystals
McDaniel, Jesse G.; Yethiraj, Arun
2017-04-26
Bilayers composed of lipid or surfactant molecules are central to biological membranes and lamellar lyotropic liquid crystalline (LLC) phases. Common to these systems are phases that exhibit either ordered or disordered packing of the hydrophobic tails. In this work, we study the impact of surfactant ordering, i.e., disordered L α and ordered L β LLC phases, on the dynamics of water and sodium ions in the lamellar phases of dicarboxylate gemini surfactants. We study the different phases at identical hydration levels by changing the length of the hydrophobic tails; surfactants with shorter tails form L α phases and those withmore » longer tails form L β phases. We find that the L α phases exhibit lower density and greater compressibility than the L β phases, with a hydration-dependent headgroup surface area. These structural differences significantly affect the relative dynamic properties of the phases, primarily the mobility of the surfactant molecules tangential to the bilayer surface, as well as the rates of water and ion diffusion. We find ~20–50% faster water diffusion in the L α phases compared to the L β phases, with the differences most pronounced at low hydration. This coupling between water dynamics and surfactant mobility is verified using additional simulations in which the surfactant tails are frozen. Our study indicates that gemini surfactant LLCs provide an important prototypical system for characterizing properties shared with more complex biological lipid membranes.« less
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Orbital Effects on Mercury's Escaping Sodium Exosphere
NASA Technical Reports Server (NTRS)
Schmidt, Carl A.; Wilson, Jody K.; Baumgardner, Jeffrey; Mendillo, Michael
2009-01-01
We present results from coronagraphic imaging of Mercury's sodium tail over a 7 deg field of view. Several sets of observations made at the McDonald Observatory since May 2007 show a tail of neutral sodium atoms stretching more than 1000 Mercury radii (R(sub m)) in length, or a full degree of sky. However, no tail was observed extending beyond 120 R(sub m) during the January 2008 MESSENGER Fly-by period, or during a similar orbital phase of Mercury in July 2008. Large changes in Mercury's heliocentric radial velocity cause Doppler shifts about the Fraunhofer absorption features; the resultant change in solar flux and radiation pressure is the primary cause of the observed variation in tail brightness. Smaller fluctuations in brightness may exist due to changing source rates at the surface, but we have no explicit evidence for such changes in this data set. The effects of radiation pressure on Mercury's escaping atmosphere are investigated using seven observations spanning different orbital phases. Total escape rates of atmospheric sodium are estimated to be between 5 and 13 x 10(exp 23) atoms/s and show a correlation to radiation pressure. Candidate sources of Mercury's sodium exosphere include desorption by UV sunlight, thermal desorption, solar wind channeled along Mercury's magnetic field lines, and micro-meteor impacts. Wide-angle observations of the full extent of Mercury's sodium tail offer opportunities to enhance our understanding of the time histories of these source rates.
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Brum, Jennifer R; Schenck, Ryan O; Sullivan, Matthew B
2013-09-01
Viruses influence oceanic ecosystems by causing mortality of microorganisms, altering nutrient and organic matter flux via lysis and auxiliary metabolic gene expression and changing the trajectory of microbial evolution through horizontal gene transfer. Limited host range and differing genetic potential of individual virus types mean that investigations into the types of viruses that exist in the ocean and their spatial distribution throughout the world's oceans are critical to understanding the global impacts of marine viruses. Here we evaluate viral morphological characteristics (morphotype, capsid diameter and tail length) using a quantitative transmission electron microscopy (qTEM) method across six of the world's oceans and seas sampled through the Tara Oceans Expedition. Extensive experimental validation of the qTEM method shows that neither sample preservation nor preparation significantly alters natural viral morphological characteristics. The global sampling analysis demonstrated that morphological characteristics did not vary consistently with depth (surface versus deep chlorophyll maximum waters) or oceanic region. Instead, temperature, salinity and oxygen concentration, but not chlorophyll a concentration, were more explanatory in evaluating differences in viral assemblage morphological characteristics. Surprisingly, given that the majority of cultivated bacterial viruses are tailed, non-tailed viruses appear to numerically dominate the upper oceans as they comprised 51-92% of the viral particles observed. Together, these results document global marine viral morphological characteristics, show that their minimal variability is more explained by environmental conditions than geography and suggest that non-tailed viruses might represent the most ecologically important targets for future research.
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Sex determination of the Acadian Flycatcher using discriminant analysis
Wilson, R.R.
1999-01-01
I used five morphometric variables from 114 individuals captured in Arkansas to develop a discriminant model to predict the sex of Acadian Flycatchers (Empidonax virescens). Stepwise discriminant function analyses selected wing chord and tail length as the most parsimonious subset of variables for discriminating sex. This two-variable model correctly classified 80% of females and 97% of males used to develop the model. Validation of the model using 19 individuals from Louisiana and Virginia resulted in 100% correct classification of males and females. This model provides criteria for sexing monomorphic Acadian Flycatchers during the breeding season and possibly during the winter.
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Supersonic aerodynamic characteristics of the North American Rockwell ATP shuttle orbiter
NASA Technical Reports Server (NTRS)
Ware, G. M.; Pencer, B., Jr.; Founier, R. H.
1973-01-01
A wind tunnel study to determine the supersonic aerodynamic characteristics of a 0.01925-scale model of the space shuttle orbiter configuration is reported. The model consisted of a low-finess-ratio body with a blended 50 swept delta wing forming an ogee planform and a center-line-mounted vertical tail. Tests were made at Mach numbers from 1.90 to 4.63, at angles of attack from -6 to 30, at angles of sideslip of 0 and 3, and at a Reynolds number, based on body length, of 5.3x 1 million.
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Camino, Nora B; Maiztegui, Bárbara
2002-07-01
Gryllophila cephalobulata n. sp. (Nematoda, Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera, Gryllotalpidae) isolated in Buenos Aires Province, is described and illustrated. It is characterized by cuticle annulated all along the length of the body; the first ring has 4 lobules, the second one has 14 lobules, the others rings are simple, the stoma is short and has 4 small teeth, the genital papillae are arranged in 5 pairs, of which 3 pairs are preanal and 2 pairs are postanal. The tail appendage of the male is long and filiform.
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Avendaño, Jorge Enrique; Donegan, Thomas M.
2015-01-01
Abstract We describe a new subspecies of Pale-bellied Tapaculo Scytalopus griseicollis from the northern Eastern Cordillera of Colombia and Venezuela. This form differs diagnosably in plumage from described subspecies Scytalopus griseicollis griseicollis and Scytalopus griseicollis gilesi and from the latter in tail length. It is also differentiated non-diagnosably in voice from both these populations. Ecological niche modelling analysis suggests that the new subspecies is restricted to the Andean montane forest and páramo north of both the arid Chicamocha valley and the Sierra Nevada del Cocuy. PMID:26085800
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Repins, Ingrid; Mansfield, Lorelle; Kanevce, Ana
Band-edge effects - including grading, electrostatic fluctuations, bandgap fluctuations, and band tails - affect chalcogenide device efficiency. These effects now require more careful consideration as efficiencies increase beyond 20%. Several aspects of the relationships between band-edge phenomena and device performance for NREL absorbers are examined. For Cu(In, Ga)Se2 devices, recent increases in diffusion length imply changes to the optimum bandgap profile. The origin, impact, and modification of electrostatic and bandgap fluctuations are also discussed. The application of the same principles to devices based on CdTe, kesterites, and emerging absorbers (Cu2SnS3, CuSbS2), considering differences in materials properties, is examined.
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Curcumin affects development of zebrafish embryo.
Wu, Jheng-Yu; Lin, Chin-Yi; Lin, Tien-Wei; Ken, Chuian-Fu; Wen, Yu-Der
2007-07-01
Embryotoxic and teratogenic effects of curcumin on the development of zebrafish embryo were investi-gated in this study. The LD(50) values of curcumin (24-h incubation) were estimated at 7.5 microM and 5 microM for embryos and larvae, respectively. The developmental defects caused by curcumin treatments include bent or hook-like tails, spinal column curving, edema in pericardial sac, retarded yolk sac resorption, and shorter body length. In curcumin-treated larvae, fluorescence signals of curcumin were found in edamae sac and some skin cells. Together, these results indicate that zebrafish are suitable model organisms to study the toxic effects of curcumin.
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Bragg scattering of electromagnetic waves by microwave-produced plasma layers
NASA Technical Reports Server (NTRS)
Kuo, S. P.; Zhang, Y. S.
1990-01-01
A set of parallel plasma layers is generated by two intersecting microwave pulses in a chamber containing dry air at a pressure comparable to the upper atmosphere. The dependencies of breakdown conditions on the pressure and pulse length are examined. The results are shown to be consistent with the appearance of tail erosion of the microwave pulse caused by air breakdown. A Bragg scattering experiment, using the plasma layers as a Bragg reflector, is then performed. Both time domain and frequency domain measurements of wave scattering are conducted. The experimental results are found to agree very well with the theory.
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Diffendorfer, James E.
2017-01-01
The familiar domestic cat is not native to southern California and is considered an invasive spe-cies by biologists and conservation organizations. When owners abandon their cats, wild or feral populations may arise, as they have in San Diego County. Cats’ pelage color, tail length, and hair thickness vary widely, given human fascination with breeding diverse phenotypes, but all have a typical felid body with upright ears, forward-looking eyes adapted for nocturnal foraging, protractible claws, and a sinuous, flexible body. Cats allowed outdoors and feral cats kill and eat a wide variety of vertebrates such as small mammals, birds, and reptiles
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Aerodynamic Characteristics of Three Deep-Stepped Planing-Tail Flying-Boat Hulls
NASA Technical Reports Server (NTRS)
Riebe, John M.; Naeseth, Rodger L.
1947-01-01
An investigation was made in the Langley 300 MPH 7- by 10-foot tunnel to determine the aerodynamic characteristics of three deep-stepped planing-tail flying-boat hulls differing only in the amount of step fairing. The hulls were derived by increasing the unfaired step depth of a planing-tail hull of a previous aerodynamic investigation to a depth about 92 percent of the hull beam. Tests were also made on a transverse-stepped hull with an extended afterbody for the purpose of comparison and in order to extend and verify the results of a previous investigation. The investigation indicated that the extended afterbody hull had a minimum drag coefficient about the same as a conventional hull, 0.0066, and an angle-of-attack range for minimum drag coefficient of 0.0057 which was 14 percent less than the transverse stepped hull with extended afterbody; the hulls with step fairing had up to 44 percent less minimum drag coefficient than the transverse-stepped hull, or slightly more drag than a streamlined body having approximately the same length and volume. Longitudinal and lateral instability varied little with step fairing and was about the same as a conventional hull.
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Maternal exposure to predator scents: offspring phenotypic adjustment and dispersal
Bestion, Elvire; Teyssier, Aimeric; Aubret, Fabien; Clobert, Jean; Cote, Julien
2014-01-01
Predation is a strong selective pressure generating morphological, physiological and behavioural responses in organisms. As predation risk is often higher during juvenile stages, antipredator defences expressed early in life are paramount to survival. Maternal effects are an efficient pathway to produce such defences. We investigated whether maternal exposure to predator cues during gestation affected juvenile morphology, behaviour and dispersal in common lizards (Zootoca vivipara). We exposed 21 gravid females to saurophagous snake cues for one month while 21 females remained unexposed (i.e. control). We measured body size, preferred temperature and activity level for each neonate, and released them into semi-natural enclosures connected to corridors in order to measure dispersal. Offspring from exposed mothers grew longer tails, selected lower temperatures and dispersed thrice more than offspring from unexposed mothers. Because both tail autotomy and altered thermoregulatory behaviour are common antipredator tactics in lizards, these results suggest that mothers adjusted offspring phenotype to risky natal environments (tail length) or increased risk avoidance (dispersal). Although maternal effects can be passive consequences of maternal stress, our results strongly militate for them to be an adaptive antipredator response that may increase offspring survival prospects. PMID:25122225
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Spiral swimming of an artificial micro-swimmer
NASA Astrophysics Data System (ADS)
Keaveny, Eric E.; Maxey, Martin R.
A device constructed from a filament of paramagnetic beads connected to a human red blood cell will swim when subject to an oscillating magnetic field. Bending waves propagate from the tip of the tail toward the red blood cell in a fashion analogous to flagellum beating, making the artificial swimmer a candidate for studying what has been referred to as micro-swimming. In this study, we demonstrate that under the influence of a rotating field the artificial swimmer will perform -type swimming. We conduct numerical simulations of the swimmer where the paramagnetic tail is represented as a series of rigid spheres connected by flexible but inextensible links. An optimal range of parameters governing the relative strength of viscous, elastic and magnetic forces is identified for swimming speed. A parameterization of the motion is extracted and examined as a function of the driving frequency. With a continuous elastica/resistive force model, we obtain an expression for the swimming speed in the low-frequency limit. Using this expression we explore further the effects of the applied field, the ratio of the transverse field to the constant field, and the ratio of the radius of the sphere to the length of the filament tail on the resulting dynamics.
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NASA Astrophysics Data System (ADS)
Seuront, Laurent; Duponchel, Anne-Charlotte; Chapperon, Coraline
2007-11-01
The two-dimensional motion behaviour of the common intertidal gastropod Littorina littorea is investigated as a function of the immersion time from three sampling sites on an exposed rocky shore. A total of 90 individuals have been individually marked and tracked over 14 consecutive daylight low tide. Successive displacements show very intermittent behaviour, with a few localised large displacements over a wide range of small displacements. We show that successive displacements are described by flight length l d heavy-tailed distributions with P(ld)∼ld-μ. The very low values of the exponent μ ( μ≈2.22, 2.43 and 2.67) indicate that L. littorea flights fall into the category of super-diffusive processes. These exponents were significantly higher than the special value μ≈2 analytically and theoretically predicted to be the most advantageous in optimising long-term encounter statistics, especially for low-prey-density scenario. As natural selection should favour flexible behaviour, leading to different optimum searching statistics, under different conditions, our results support the idea that the differences in food concentration and distribution encountered at the different sites by L. littorea led to different heavy-tailed distributions observed for the most extreme displacements.
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First record of laughing gull (Larus atricilla) in French Polynesia
Vanderwerf, Eric A.; Pierce, Ray J.; Tibbitts, T.L.; Salducci, J.-M.; Gill, V.A.; Wragg, Graham
2004-01-01
On 6 March 2003 at 0800 h and again at 1300 h, while preparing for biological surveys in the Tuamotu and Gambier archipelagos of French Polynesia, we observed an immature gull flying in Rikitea harbor on Mangareva in the Gambier Islands. On both occasions we observed the gull for several minutes at distances as close as 20 m while it flew around the waterfront. It was a medium-sized gull, with long, pointed wings. The head was white with dark streaks and smudging on the nape. The bill was dark and of moderate length and thickness. The back and inner secondaries were dark grey, and the outer secondaries and primaries were a mottled dusky grey-brown. There was a complete, broad, dark band across the tip of the tail. These characters, particularly the long, pointed wings and broad tail band, led us to conclude that the bird was a laughing gull (Larus atricilla) in first winter plumage. Franklin’s gull (L. pipixcan) is similar in appearance and has been reported previously in several Pacific island groups (King 1967; Pratt et al. 1987), but can be distinguished from L. atricilla by its slightly smaller size, smaller bill, and narrower, incomplete tail band (Sibley 2000).
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Optimizing an undulating magnetic microswimmer for cargo towing
NASA Astrophysics Data System (ADS)
Or, Yizhar; Gutman, Emiliya
2015-11-01
One of the promising applications of robotic microswimmers is towing a cargo for controlled drug delivery, micro-surgery or tumor detection. This capability has been demonstrated by the magnetically-actuated microswimmer of Dreyfus et al. [Nature 2005] in which a red blood cell was attached to a chain of magnetic beads connected by flexible DNA links. A key question is what should be the optimal size of the magnetic tail for towing a given cargo. This question is addressed here for the simplest theoretical model of a magnetic microswimmer under planar undulations - a spherical load connected by a torsion spring to a magnetized rigid slender link. The swimmer's dynamics is formulated assuming negligible hydrodynamic interaction and leading-order expressions for the resulting motion are obtained explicitly under small amplitude approximation. Optimal combinations of magnetic actuation frequency, torsion stiffness, and tail length for maximizing displacement or average speed are obtained. The theoretical results are compared with several reported magnetic microswimmers, and also agree qualitatively with recent results on cargo towing by screw rotation of magnetic helical tails [Walker et al., ACS Nano Letters 2015]. This work is supported by the Israeli Science Foundation (ISF) under Grant No. 567/14.
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NASA Astrophysics Data System (ADS)
Mishin, V. M.; Russell, C. T.; Saifudinova, T. I.; Bazarzhapov, A. D.
2000-10-01
We define an expansion onset (synonymous with the main breakup) to be one with sufficient signatures of open tail reconnection. Earlier onsets, which we term initial onsets, occur before the expansion onset, without the signatures of open tail reconnection but with other signs of a clear substorm onset. These two types of substorm onsets and their timing are discussed herein in a study of selected substorm-like events. During the 10-hour interval studied, five impulses of the Perreault-Akasofu index ɛ were observed with comparable peak values. However, the observed magnetospheric responses were very different in terms of equatorward motion and poleward expansion of the auroral oval. We conclude that the occurrence either of an initial onset or of a full onset (under similar boundary conditions) depends on the amount of stored free energy, proportional to the tail length, which is controlled by the input power. The earlier or initial onset marks a sudden change in the convection pattern in the nightside. This onset could mark the initiation of reconnection on closed field lines while the expansion onset could mark the initiation of reconnection on open field lines.
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Wang, Muhan; Fang, Timing; Wang, Pan; Tang, Xinpeng; Sun, Baojiang; Zhang, Jun; Liu, Bing
2016-10-04
Hybrid surfactants containing both fluorocarbon (FC) and hydrocarbon (HC) chains, as effective CO 2 -philic surfactants, could improve the solubility of polar substances in supercritical CO 2 . Varying the length of the HC of hybrid surfactants is an effective way to improve the CO 2 -philicity. In this paper, we have investigated the effects of the HC length on the self-assembly process and the CO 2 -philicity of hybrid surfactants (F7Hn, n = 1, 4, 7 and 10) in water/CO 2 mixtures using molecular dynamics simulations. It is found that the self-assembly time of F7Hn exhibits a maximum when the length of the HC is equal to that of the FC (F7H7). In this case, the investigation of H-bonds between the water core and CO 2 phase shows that F7H7 has the strongest CO 2 -philicity because it has the best ability to separate water and CO 2 . To explain the origin of the differences in separation ability, the analysis of the structures of the reverse micelles shows that there are two competing mechanisms with a shortening HC. Firstly, the volume of F7Hn is reduced, which thus decreases the separation ability. Moreover, this also leads to the curved conformation of the FC. As a result, the separation ability is enhanced. These two mechanisms are balanced in F7H7, which has the best ability to separate water and CO 2 . Our simulation results demonstrate that the increased volume and the curved conformation of the hybrid surfactant tail could enhance the CO 2 -philicity in F7Hn surfactants. It is expected that this work will provide valuable information for the design of CO 2 -philic surfactants.
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Nonequilibrium steady state of a weakly-driven Kardar–Parisi–Zhang equation
NASA Astrophysics Data System (ADS)
Meerson, Baruch; Sasorov, Pavel V.; Vilenkin, Arkady
2018-05-01
We consider an infinite interface of d > 2 dimensions, governed by the Kardar–Parisi–Zhang (KPZ) equation with a weak Gaussian noise which is delta-correlated in time and has short-range spatial correlations. We study the probability distribution of the interface height H at a point of the substrate, when the interface is initially flat. We show that, in stark contrast with the KPZ equation in d < 2, this distribution approaches a non-equilibrium steady state. The time of relaxation toward this state scales as the diffusion time over the correlation length of the noise. We study the steady-state distribution using the optimal-fluctuation method. The typical, small fluctuations of height are Gaussian. For these fluctuations the activation path of the system coincides with the time-reversed relaxation path, and the variance of can be found from a minimization of the (nonlocal) equilibrium free energy of the interface. In contrast, the tails of are nonequilibrium, non-Gaussian and strongly asymmetric. To determine them we calculate, analytically and numerically, the activation paths of the system, which are different from the time-reversed relaxation paths. We show that the slower-decaying tail of scales as , while the faster-decaying tail scales as . The slower-decaying tail has important implications for the statistics of directed polymers in random potential.
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Statical longitudinal stability of airplanes
NASA Technical Reports Server (NTRS)
Warner, Edward P
1921-01-01
This report, which is a continuation of the "Preliminary report on free flight testing" (report no. NACA-TR-70), presents a detailed theoretical analysis of statical stability with free and locked controls and also the results of many free flight test on several types of airplanes. In developing the theory of stability with locked controls an expression for pitching moment is derived in simple terms by considering the total moment as the sum of the moments due to wings and tail surface. This expression, when differentiated with respect to angle of incidence, enables an analysis to be made of the factors contributing to the pitching moment. The effects of slipstream and down wash are also considered and it is concluded that the C. G. Location has but slight effect or stability, and that stability is much improved by increasing the efficiency of the tail surfaces, which may be done by using an "inverted" tail plane. The results of free flight tests with locked controls are discussed at length and it is shown that the agreement between the experimental results and theory is very satisfactory. The theory of stability with free controls is not amendable to the simple mathematical treatment used in the case of locked controls, but a clear statement of the conditions enables several conclusions to be drawn, one of which is that the fixed tail surfaces should be much larger than the movable surfaces.
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Global simulation of formation and evolution of plasmoid and flux-rope in the Earth's Magnetotail
NASA Astrophysics Data System (ADS)
Ge, Y.; Raeder, J.; Du, A.
2014-12-01
The observation of plasmoids and flux-ropes in the Earth's magnetotail was crucial to establish the simultaneous presence of multiple x-lines in the tail, and has become the basis for the Near Earth Neutral Line (NENL) model of substorms. While the "classical" NENL model envisions x-lines that extend across the entire tail, recent observations have shown that neither do the x-lines and resulting plasmoids encompass the entire tail, nor do the x-lines have to lie along the y-axis. The fragmentation of the tail by spatially and temporally limited x-lines has important consequences for the mass and energy budget of the tail. Recent ARTEMIS observations have shown that the plasmoids in the distant tail are limited in the Y direction and some flux ropes are tilted during their tailward propagation. Understanding their formation and evolution during their propagation through the magnetotail shall shred more light on the general energy and flux transport of the Earth's magnetosphere. In this study we simulate plasmoids and flux-ropes in the Earth's magnetotail using the Open Global Geospace Circulation Model (OpenGGCM). We investigate the generation mechanisms for tail plasmoids and flux-ropes and their evolution as they propagate in the magnetotail. The simulation results show that the limited extend of NENL controls the length or the Y scale of tail plasmoid and flux rope. In addition, by studying their 3D magnetic topology we find that the tilted flux rope forms due to a progressive spreading of reconnection line along the east-west direction, which produces and releases two ends of the flux rope at different times and in different speeds. By constructing a catalogue of observational signatures of plasmoid and flux rope we compare the differences of their signatures and find that large-scale plasmoids have much weaker core fields than that inside the small-scale flux ropes.
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Skinner, Heather M; Durso, Andrew M; Neuman-Lee, Lorin A; Durham, Susan L; Mueller, Sarah D; French, Susannah S
2016-11-01
Organisms must balance energy invested into self-maintenance, reproduction, and somatic growth over their lifetime. In this study, the effects of diet restriction and diet complexity on side-blotched lizards (Uta stansburiana) were analyzed. Thirty male lizards, housed in the laboratory, were fed either an ad libitum or a restricted diet for 18 days (phase 1). Individuals from both treatments were then assigned to a diet of the same quantity of food that was either simple (only crickets) or complex (crickets, cockroaches, waxworms, and mealworms) for 35 days (phase 2). We evaluated (1) how diet restriction affected life history strategies and (2) how diet complexity affected recovery from diet restriction as measured at the end of phase 2 by body mass, snout-vent length, calculated body condition score, wound healing, tail regrowth, bacterial killing ability, oxidative stress, and plasma testosterone and corticosterone concentrations. Lizards without diet restriction allocated more energy to self-maintenance (i.e., maintaining higher body condition scores, healing wounds more quickly) than lizards with diet restriction. Lizards with diet restriction had higher plasma testosterone concentrations and larger increases in snout-vent lengths than those fed ad libitum, which may reflect allocations toward reproduction and somatic growth. A complex diet resulted in better body condition and faster tail regrowth than a simple diet, suggesting that a complex diet enhanced recovery from diet restriction, although long-term life history choices remained unaltered. Finally, lizards on a complex diet consumed substantially less food while maintaining higher body condition, suggesting that key nutrients may be lacking from a simple diet. © 2017 Wiley Periodicals, Inc.