Journal articles on the topic 'Envelope'
To see the other types of publications on this topic, follow the link: Envelope.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Envelope.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Dai, Ming-Wu, and Kai-Jun Luo. "Envelope-Fusion-Syncytium Formation in Microplitis bicoloratus bracovirus Maturation." Viruses 14, no. 10 (October 2, 2022): 2183. http://dx.doi.org/10.3390/v14102183.
Full textAbstract:
The viral envelope is essential for virus maturation. Virus-mediated syncytium formations are induced by viral envelope proteins that cause membrane fusion of the infected cells. Polydnaviridae (Polydnavirus) are enveloped viruses with multiple nucleocapsids, and virions mature in symbiotic parasitoid wasp ovaries. However, the mechanism governing the envelope packaging of multiple nucleocapsids remains unclear. In this study, we used transmission electron microscopy to examine the process whereby multiple nucleocapsids of Microplitis bicoloratus bracovirus are packaged into an envelope and observed envelope-fusion-syncytium formation in symbiotic wasp calyx cells during virus maturation. The virus maturation process in calyx cells comprised four stages: pre-virogenic stroma, virogenic stroma, assembly, and fusion. Each virus contained a single envelope with one nucleocapsid in the assembly stage; multiple envelopes then fused to form a viral envelope with multiple nucleocapsids (i.e., the envelope-fusion-syncytium) around the envelope fusion core in the fusion stage. The envelope-fusion-syncytium then stabilized the virions that were released into the lumen of the ovary across the calyx epithelial layer. The phagocytic calyx epithelial cells on the border of the calyx and ovary lumen cleared the majority of non-enveloped nucleocapsids. In contrast, non-phagocytic calyx epithelial cells with microvilli and a cuticular line between the ovary wall and the lumen remained intact in the ovary lumen. These results indicate that envelope-fusion-syncytium formation is important for packaging multiple nucleocapsids in bracovirus maturation.
2
Jones, MK. "Formation of the Paruterine Capsules and Embryonic Envelopes in Cylindrotaenia-Hickmani (Jones, 1985) (Cestoda, Nematotaeniidae)." Australian Journal of Zoology 36, no. 5 (1988): 545. http://dx.doi.org/10.1071/zo9880545.
Full textAbstract:
The development of embryonic envelopes and paruterine capsules in Cylindrotaenia hickmani (Jones 1985) Jones, 1987 were studied using transmission electron microscopy. The embryonic envelopes of C. hickmani form in a similar way to those of other cyclophyllideans. The extant embryonic envelopes in fully developed eggs are: the thin, featureless outer envelope; the inner envelope, which forms an oncospheral membrane; embryophore; and an electron-dense peripheral cytoplasmic layer that lies immediately internal to the external plasma membrane of the inner envelope. Processes of uterine epithelial cells envelop the outer capsule of early embryos. Both the uterine envelope and outer capsule are lost as eggs develop. Paruterine organs are complex, paired structures that form lipid and flattened cellular processes for inclusion within paruterine capsules. Paruterine capsules are complex parenchymal structures containing eggs and the products of the paruterine organs. The possession of such complex paruterine envelopes suggests that the life cycles of nematotaeniids are terrestrial. The sequence of events in paruterine capsule formation in nematotaeniids is unlike that seen in other cyclophyllidean groups with paruterine capsules and it is unlikely that nematotaeniids are closely related to such cestodes.
3
Usui, Noriko, Atsuo Ogura, Yasuyuki Kimura, and Ryuzo Yanagimachi. "Sperm nuclear envelope: breakdown of intrinsic envelope and de novo formation in hamster oocytes or eggs." Zygote 5, no. 1 (February 1997): 35–46. http://dx.doi.org/10.1017/s0967199400003543.
Full textAbstract:
SummaryDuring fertilisation of a fully mature oocyte, the sperm intrinsic nuclear envelope (SINE) disappears soon after sperm-oocyte fusion. A new nuclear envelope appears around the decondensed sperm chromatin when the oocyte reaches telophase II. Whether the SINE persists or rapidly disappears after sperm entery into immature oocytes or fertilised eggs has been controversial. Nuclear envelopes have been demonstrated around the sperm chromatin, which cannot be decondensed within the ooplasm of these oocytes or eggs, but whether these envelopes are persisting SINEs or newly formed envelopes has been apoint of dispute. To resolve this issue, the fate of the germinal vesicle stage(GV oocytes) or fertilised eggs at the pronuclear stage(PN eggs). The SINEs disappeared quikly within these oocytes or eggs, like those within maturing or mature oocytes, suggesting that the envelops around the sperm chromatin must be newly formed after SINE breakdown. To obtain further evidence, a detergent-treated, SINE-free sperm nucleus was injected into a PN egg. A new envelope appeared around the still-condensed or partially decondensed sperm chromatin within 3h after injection. Thus, disassembly of the SINE within ooplasm, unlike that of nuclear envelopes of other cells at prophase, is independent of the cell cycle stage of the oocyte or egg, whereas the ability of the ooplasm to assemble the new envelope is restricted to certain periods of the cycle. i.e. early prophase and telophase during meiosis and interphase, periods when active M-phase Promoting factor (MPF) is absent from the ooplasm.
4
Zhang, X., C. E. Lee, and X. Shao. "Envelopes in multivariate regression models with nonlinearity and heteroscedasticity." Biometrika 107, no. 4 (June 17, 2020): 965–81. http://dx.doi.org/10.1093/biomet/asaa036.
Full textAbstract:
Summary Envelopes have been proposed in recent years as a nascent methodology for sufficient dimension reduction and efficient parameter estimation in multivariate linear models. We extend the classical definition of envelopes in Cook et al. (2010) to incorporate a nonlinear conditional mean function and a heteroscedastic error. Given any two random vectors ${X}\in\mathbb{R}^{p}$ and ${Y}\in\mathbb{R}^{r}$, we propose two new model-free envelopes, called the martingale difference divergence envelope and the central mean envelope, and study their relationships to the standard envelope in the context of response reduction in multivariate linear models. The martingale difference divergence envelope effectively captures the nonlinearity in the conditional mean without imposing any parametric structure or requiring any tuning in estimation. Heteroscedasticity, or nonconstant conditional covariance of ${Y}\mid{X}$, is further detected by the central mean envelope based on a slicing scheme for the data. We reveal the nested structure of different envelopes: (i) the central mean envelope contains the martingale difference divergence envelope, with equality when ${Y}\mid{X}$ has a constant conditional covariance; and (ii) the martingale difference divergence envelope contains the standard envelope, with equality when ${Y}\mid{X}$ has a linear conditional mean. We develop an estimation procedure that first obtains the martingale difference divergence envelope and then estimates the additional envelope components in the central mean envelope. We establish consistency in envelope estimation of the martingale difference divergence envelope and central mean envelope without stringent model assumptions. Simulations and real-data analysis demonstrate the advantages of the martingale difference divergence envelope and the central mean envelope over the standard envelope in dimension reduction.
5
Pickl, Winfried F., Felipe X. Pimentel-Muiños, and Brian Seed. "Lipid Rafts and Pseudotyping." Journal of Virology 75, no. 15 (August 1, 2001): 7175–83. http://dx.doi.org/10.1128/jvi.75.15.7175-7183.2001.
Full textAbstract:
ABSTRACT Specific interactions between envelope and core proteins govern the membrane assembly of most enveloped viruses. Despite this, mixed infections lead to pseudotyping, the association of the viral cores of one virus with the envelopes of another. How does this occur? We show here that the detergent-insoluble lipid rafts of the plasma membrane function as a natural meeting point for the transmembrane and core components of a phylogenetically diverse collection of enveloped viruses. As a result, viral particles preferentially incorporate both the envelope components of other viruses as well as the extra- and intracellular constituents of host cell lipid rafts, including gangliosides, glycosyl phosphatidylinositol-anchored surface proteins, and intracellular signal transduction molecules. Pharmacological disruption of lipid rafts interferes with virus production.
6
Sun, Xiangjie, and Gary R. Whittaker. "Role for Influenza Virus Envelope Cholesterol in Virus Entry and Infection." Journal of Virology 77, no. 23 (December 1, 2003): 12543–51. http://dx.doi.org/10.1128/jvi.77.23.12543-12551.2003.
Full textAbstract:
ABSTRACT Enveloped viruses are highly dependent on their lipid envelopes for entry into and infection of host cells. Here, we have examined the role of cholesterol in the virus envelope, using methyl-β-cyclodextrin depletion. Pretreatment of virions with methyl-β-cyclodextrin efficiently depleted envelope cholesterol from influenza virus and significantly reduced virus infectivity in a dose-dependent manner. A nonenveloped virus, simian virus 40, was not affected by methyl-β-cyclodextrin treatment. In the case of influenza virus, infectivity could be partially rescued by the addition of exogenous cholesterol. Influenza virus morphology, binding, and internalization were not affected by methyl-β-cyclodextrin depletion, whereas envelope cholesterol depletion markedly affected influenza virus fusion, as measured by a specific reduction in the infectivity of viruses induced to fuse at the cell surface and by fluorescence-dequenching assays. These data suggest that envelope cholesterol is a critical factor in the fusion process of influenza virus.
7
Cross, N. L., T. C. Slezynger, and L. Z. Holland. "Isolation and partial characterization of Urechis caupo egg envelopes." Journal of Cell Science 74, no. 1 (March 1, 1985): 193–205. http://dx.doi.org/10.1242/jcs.74.1.193.
Full textAbstract:
Eggs of Urechis caupo are surrounded by a congruent to 0.9 micrometer thick egg envelope and, attached to that, a peripheral jelly layer about 3 micrometers thick. Before fertilization, the sperm undergoes the acrosome reaction and binds to the egg envelope. As part of a study of the induction of the acrosome reaction and sperm binding in Urechis, we have developed a method to prepare an egg envelope fraction by differential centrifugation. The isolation procedure removes much of the jelly layer, but does not alter the fine structure of the envelope. When a sperm contacts an isolated envelope, it undergoes a normal acrosome reaction and binds to the envelope's outer face. Electrophoresis of the envelope fraction on sodium dodecyl sulphate (SDS)/polyacrylamide gels revealed six major components stained by Coomassie Blue, of which four are stained by the periodic acid-Schiff reagents (PAS). To measure the degree of enrichment of the envelope fraction, envelopes were isolated from eggs that had been externally radio-iodinated; the specific activity of the envelope fraction was 17 +/− 3 times greater than that of intact eggs. The amino acid composition of the envelope fraction is dominated by Gly (19 mole %), Asx (11%), Thr (11%), Ser (8%), Ala (8%) and Glx (8%). The sugars fucose, xylose, mannose, galactose, glucose, N-acetylglucosamine and N-acetylgalactosamine were detected by gas-liquid chromatography. We also investigated whether the egg envelope changes at fertilization. No change was detected in the electrophoretic 125I pattern of externally radio-iodinated eggs, and the envelope fractions prepared from unfertilized and fertilized eggs produced the same Coomassie Blue pattern on SDS/polyacrylamide gels.
8
Meng, Xi, Xinyu Shi, Yanna Gao, and Tao Luo. "Composition of cooling load formed by non-transparent envelopes of a common office building under air-conditioning intermittent operation." Journal of Building Physics 43, no. 6 (July 1, 2019): 528–44. http://dx.doi.org/10.1177/1744259119857756.
Full textAbstract:
Under air-conditioning intermittent operation, interior envelopes become the quasi-exterior ones of a partial room and thereby may cause the specified heat loss. However, it is unknown for the heat transfer capacity rate of interior envelopes in the room heat loss, which is of vital significance on the optimization direction of envelopes. To analyze the cooling load composition formed by non-transparent envelopes, an office building was chosen and inner surface heat flows in the studied room were measured under the different intermittent groups of air-conditioning in the adjacent rooms, and combined with the envelop area and heat flow values, the heat transfer capacity through the different envelops could be gained. The results showed that the air-conditioning operation in the adjacent rooms had a large effect on the heat transfer capacities, and the higher the room area, the more remarkable the air-conditioning operation in the adjacent rooms. The average heat transfer capacity rate of the exterior envelope was 21%–35% for room with two exterior walls and only 7%–10% for room with one exterior wall, which were much lower than those of the interior envelopes. It showed that thermal performance of the interior envelopes should be paid more attention to under air-conditioning intermittent operation.
9
Ahmed, S., K. Waterhouse, and A. Vitali. "P.084 Single-centre follow-up of TYRX Antibiotic Envelope for neuromodulation unit implantation." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 44, S2 (June 2017): S34—S35. http://dx.doi.org/10.1017/cjn.2017.168.
Full textAbstract:
Background: Studies have placed the rate of infection associated with neuromodulation units to be up to 20%. We present our experience with the TYRX absorbable antibiotic envelope. Our length of follow-up adds to the body of evidence around the use of antibiotic envelops. Methods: We conducted a retrospective chart review of patients referred to our center for either new implantation or revision of neuromodulation units between July 2014 and September 2016. Consecutive cases were included for analysis. We included a control group of consecutive patients with neuromodulation units placed immediately prior to our experience with the TYRX envelopes for comparison Results: Between July 2014 and September 2016, 76 patients had 81 instances of neuromodulation unit insertion. All patients received the TYRX antibiotic envelope. There were no incidences of infection involving antibiotic envelope-containing implants over an average follow-up period of 11 months. In 77 consecutive cases of neuromodulation unit implantation prior to usage of the antibiotic pouch, there were 4 instances of infection (5.2%). Conclusions: Our single center experience demonstrates a significant drop in the rate of infections with the use of an antibiotic envelope for neuromodulation unit implantation. We consider the routine use of the envelope to be a cost-effective method of infection avoidance.
10
Buchmann, Jan P., and Edward C. Holmes. "Cell Walls and the Convergent Evolution of the Viral Envelope." Microbiology and Molecular Biology Reviews 79, no. 4 (September 16, 2015): 403–18. http://dx.doi.org/10.1128/mmbr.00017-15.
Full textAbstract:
SUMMARYWhy some viruses are enveloped while others lack an outer lipid bilayer is a major question in viral evolution but one that has received relatively little attention. The viral envelope serves several functions, including protecting the RNA or DNA molecule(s), evading recognition by the immune system, and facilitating virus entry. Despite these commonalities, viral envelopes come in a wide variety of shapes and configurations. The evolution of the viral envelope is made more puzzling by the fact that nonenveloped viruses are able to infect a diverse range of hosts across the tree of life. We reviewed the entry, transmission, and exit pathways of all (101) viral families on the 2013 International Committee on Taxonomy of Viruses (ICTV) list. By doing this, we revealed a strong association between the lack of a viral envelope and the presence of a cell wall in the hosts these viruses infect. We were able to propose a new hypothesis for the existence of enveloped and nonenveloped viruses, in which the latter represent an adaptation to cells surrounded by a cell wall, while the former are an adaptation to animal cells where cell walls are absent. In particular, cell walls inhibit viral entry and exit, as well as viral transport within an organism, all of which are critical waypoints for successful infection and spread. Finally, we discuss how this new model for the origin of the viral envelope impacts our overall understanding of virus evolution.
11
Greenberg, David, Jessica J. M. Monaghan, Mathias Dietz, Torsten Marquardt, and David McAlpine. "Influence of envelope waveform on ITD sensitivity of neurons in the auditory midbrain." Journal of Neurophysiology 118, no. 4 (October 1, 2017): 2358–70. http://dx.doi.org/10.1152/jn.01048.2015.
Full textAbstract:
Interaural time differences (ITDs) conveyed by the modulated envelopes of high-frequency sounds can serve as a cue for localizing a sound source. Klein-Hennig et al. ( J Acoust Soc Am 129: 3856, 2011) demonstrated the envelope attack (the rate at which stimulus energy in the envelope increases) and the duration of the pause (the interval between successive envelope pulses) as important factors affecting sensitivity to envelope ITDs in human listeners. Modulated sounds with rapid attacks and long pauses produce the lowest ITD discrimination thresholds. The duration of the envelope’s sustained component (sustain) and the rate at which stimulus energy falls at the offset of the envelope (decay) are only minor factors. We assessed the responses of 71 single neurons, recorded from the midbrains of 15 urethane-anesthetized tri-colored guinea pigs, to envelope shapes in which the four envelope components, i.e., attack, sustain, decay, and pause, were systematically varied. We confirmed the importance of the attack and pause components in generating ITD-sensitive responses. Analysis of neural firing rates demonstrated more neurons (49/71) show ITD sensitivity in response to “damped” stimuli (fast attack and slow decay) compared with “ramped” stimuli (slow attack and fast decay) (14/71). Furthermore, the lowest threshold for the damped stimulus (91 μs) was lower by a factor of 4 than that for the temporally reversed ramped envelope shape (407 μs). The data confirm the importance of fast attacks and optimal pause durations in generating sensitivity to ITDs conveyed in the modulated envelopes of high-frequency sounds and are incompatible with models of ITD processing based on the integration of sound energy over time. NEW & NOTEWORTHY Using single-neuron electrophysiology, we show that the precise shape of a sound’s “energy envelope” is a critical factor in determining how well midbrain neurons are able to convey information about auditory spatial cues. Consistent with human behavioral performance, sounds with rapidly rising energy and relatively long intervals between energy bursts are best at conveying spatial information. The data suggest specific sound energy patterns that might best be applied to hearing devices to aid spatial listening.
12
Biersteker, John B., and Hilke E. Schlichting. "Atmospheric mass-loss due to giant impacts: the importance of the thermal component for hydrogen–helium envelopes." Monthly Notices of the Royal Astronomical Society 485, no. 3 (March 16, 2019): 4454–63. http://dx.doi.org/10.1093/mnras/stz738.
Full textAbstract:
ABSTRACT Systems of super-Earths and mini-Neptunes display striking variety in planetary bulk density and composition. Giant impacts are expected to play a role in the formation of many of these worlds. Previous works, focused on the mechanical shock caused by a giant impact, showed that these impacts can eject large fractions of the planetary envelope, offering a partial explanation for the observed compositional diversity. Here, we examine the thermal consequences of giant impacts, and show that the atmospheric loss caused by these effects can significantly exceed that caused by mechanical shocks for hydrogen–helium (H/He) envelopes. During a giant impact, part of the impact energy is converted into thermal energy, heating the rocky core and envelope. We find that the ensuing thermal expansion of the envelope can lead to a period of sustained, rapid mass-loss through a Parker wind, partly or completely eroding the H/He envelope. The degree of atmospheric loss depends on the planet’s orbital distance from its host star and its initial thermal state, and hence age. Close-in planets and younger planets are more susceptible to impact-triggered atmospheric loss. For planets where the heat capacity of the core is much greater than the envelope’s heat capacity (envelope mass fractions ≲4 per cent), the impactor mass required for significant atmospheric removal is Mimp/Mp ∼ μ/μc ∼ 0.1, approximately the ratio of the heat capacities of the envelope and core. Conversely, when the envelope dominates the planet’s heat capacity, complete loss occurs when the impactor mass is comparable to the envelope mass.
13
Zhuang, Zhe, Jianming Ding, Andy C. Tan, Ying Shi, and Jianhui Lin. "Fault Detection of High-Speed Train Wheelset Bearing Based on Impulse-Envelope Manifold." Shock and Vibration 2017 (2017): 1–17. http://dx.doi.org/10.1155/2017/2104720.
Full textAbstract:
A novel fault detection method employing the impulse-envelope manifold is proposed in this paper which is based on the combination of convolution sparse representation (CSR) and Hilbert transform manifold learning. The impulses with different sparse characteristics are extracted by the CSR with different penalty parameters. The impulse-envelope space is constructed through Hilbert transform on the extracted impulses. The manifold based on impulse-envelope space (impulse-envelope manifold) is executed to learn the low-dimensionality intrinsic envelope of vibration signals for fault detection. The analyzed results based on simulations, experimental tests, and practical applications show that (1) the impulse-envelope manifold with both isometric mapping (Isomap) and locally linear coordination (LLC) can be successfully used to extract the intrinsic envelope of the impulses where local tangent space analysis (LTSA) fails to perform and (2) the impulse-envelope manifold with Isomap outperforms those with LLC in terms of strengthening envelopes and the number of extracted harmonics. The proposed impulse-envelope manifold with Isomap is superior in extracting the intrinsic envelope, strengthening the amplitude of intrinsic envelope spectra, and enlarging the harmonic number of fault-characteristic frequency. The proposed technique is highly suitable for extracting intrinsic envelopes for bearing fault detection.
14
Kalmokoff, M. L., J. W. Austin, M. F. Whitford, and R. M. Teather. "Characterization of a major envelope protein from the rumen anaerobeSelenomonas ruminantiumOB268." Canadian Journal of Microbiology 46, no. 4 (April 1, 2000): 295–303. http://dx.doi.org/10.1139/w99-149.
Full textAbstract:
Cell envelopes from the Gram-negative staining but phylogenetically Gram-positive rumen anaerobe Selenomonas ruminantium OB268 contained a major 42 kDa heat modifiable protein. A similarly sized protein was present in the envelopes of Selenomonas ruminantium D1 and Selenomonas infelix. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of Triton X-100 extracted cell envelopes from S. ruminantium OB268 showed that they consisted primarily of the 42 kDa protein. Polyclonal antisera produced against these envelopes cross-reacted only with the 42 kDa major envelope proteins in both S. ruminantium D1 and S. infelix, indicating a conservation of antigenic structure among each of the major envelope proteins. The N-terminus of the 42 kDa S. ruminantium OB268 envelope protein shared significant homology with the S-layer (surface) protein from Thermus thermophilus, as well as additional envelope proteins containing the cell surface binding region known as a surface layer-like homologous (SLH) domain. Thin section analysis of Triton X-100 extracted envelopes demonstrated the presence of an outer bilayer overlaying the cell wall, and a regularly ordered array was visible following freeze-fracture etching through this bilayer. These findings suggest that the regularly ordered array may be composed of the 42 kDa major envelope protein. The 42 kDa protein has similarities with regularly ordered outer membrane proteins (rOMP) reported in certain Gram-negative and ancient eubacteria.Key words: Selenomonas envelope surface SLH domain.
15
Misener, William, and Hilke E. Schlichting. "To cool is to keep: residual H/He atmospheres of super-Earths and sub-Neptunes." Monthly Notices of the Royal Astronomical Society 503, no. 4 (March 27, 2021): 5658–74. http://dx.doi.org/10.1093/mnras/stab895.
Full textAbstract:
ABSTRACT Super-Earths and sub-Neptunes are commonly thought to have accreted hydrogen/helium envelopes, consisting of a few to ten percent of their total mass, from the primordial gas disc. Subsequently, hydrodynamic escape driven by core-powered mass-loss and/or photoevaporation likely stripped much of these primordial envelopes from the lower mass and closer-in planets to form the super-Earth population. In this work, we show that after undergoing core-powered mass-loss, some super-Earths can retain small residual H/He envelopes. This retention is possible because, for significantly depleted atmospheres, the density at the radiative–convective boundary drops sufficiently such that the cooling time-scale becomes shorter than the mass-loss time-scale. The residual envelope is therefore able to contract, terminating further mass-loss. Using analytic calculations and numerical simulations, we show that the mass of primordial H/He envelope retained as a fraction of the planet’s total mass, fret, increases with increasing planet mass, Mc, and decreases with increasing equilibrium temperature, Teq, scaling as $f_\mathrm{ret} \propto M_\mathrm{c}^{3/2} T_\mathrm{eq}^{-1/2} \exp {[M_\mathrm{c}^{3/4} T_\mathrm{eq}^{-1}]}$. fret varies from <10−8 to about 10−3 for typical super-Earth parameters. To first order, the exact amount of left-over H/He depends on the initial envelope mass, the planet mass, its equilibrium temperature, and the envelope’s opacity. These residual hydrogen envelopes reduce the atmosphere’s mean molecular weight compared to a purely secondary atmosphere, a signature observable by current and future facilities. These remnant atmospheres may, however, in many cases be vulnerable to long-term erosion by photoevaporation. Any residual hydrogen envelope likely plays an important role in the long-term physical evolution of super-Earths, including their geology and geochemistry.
16
Persad, A., S. Ahmed, R. Mercure-Cyr, K. Waterhouse, and A. Vitali. "P.150 Use of Antibacterial Envelopes for Prevention of Infection in Neuromodulation." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 48, s3 (November 2021): S63. http://dx.doi.org/10.1017/cjn.2021.426.
Full textAbstract:
Background: Neuromodulation unit placement carries a historic infection rate as high as 12%. TYRX antibacterial envelopes (Medtronic Inc., Minneapolis, MN), which are absorbable mesh envelopes that elute minocycline and rifampin, have been used in implantable cardiac devices with substantial risk reduction for infection. Methods: We conducted a retrospective cohort study of consecutive implantable pulse generator (IPG) and intrathecal pump unit implantation with a TYRX antibacterial envelope©. This cohort was then compared to a historical cohort of consecutive patients undergoing IPG or pump placement or revision prior to the use of the envelopes. Results: In the pre-envelope cohort of 151 IPGs in 116 patients, the infection rate was 18/151 (11.9%). In the antibacterial envelope cohort of 233 IPGs in 185 patients, the infection rate was (2.1%). The absolute risk reduction was 4.6% (95% CI, 0.045-0.048), The pre-envelope cohort of 41 pumps in 39 patients, the infection rate was 6/41 (14.6%). In the antibacterial envelope cohort of 59 pumps in 54 patients, the infection rate was (1.7%). The absolute risk reduction was 12.9% (95% CI 1.6-24.3). Conclusions: Usage of an antibacterial envelope for neuromodulation has resulted in a lower infection rate at our center. Based on these results, we recommend the use of antimicrobial envelopes.
17
Sathyadev, D. P., and A. H. Soni. "Instantaneous Kinematics of a Tangent-Plane in Two-Parameter Space Motion." Journal of Mechanical Design 116, no. 1 (March 1, 1994): 210–14. http://dx.doi.org/10.1115/1.2919349.
Full textAbstract:
A tangent-plane undergoing two-parameter motion envelopes a surface called the tangent-plane envelope. Such surfaces can be considered as the envelope of a two-parameter family of planes or ∞2 family of planes. The properties of the tangent-plane motion are characterized through the properties of the spherical image of the normal to the surface it envelopes. This paper presents a methodology to locate a family of planes that envelope surfaces with similar characteristics.
18
McDonnell, Mark D., Alex J. Grant, Ingmar Land, Badri N. Vellambi, Derek Abbott, and Ken Lever. "Gain from the two-envelope problem via information asymmetry: on the suboptimality of randomized switching." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2134 (May 11, 2011): 2825–51. http://dx.doi.org/10.1098/rspa.2010.0541.
Full textAbstract:
The two-envelope problem (or exchange problem) is one of maximizing the payoff in choosing between two values, given an observation of only one. This paradigm is of interest in a range of fields from engineering to mathematical finance, as it is now known that the payoff can be increased by exploiting a form of information asymmetry. Here, we consider a version of the ‘two-envelope game’ where the envelopes’ contents are governed by a continuous positive random variable. While the optimal switching strategy is known and deterministic once an envelope has been opened, it is not necessarily optimal when the content's distribution is unknown. A useful alternative in this case may be to use a switching strategy that depends randomly on the observed value in the opened envelope. This approach can lead to a gain when compared with never switching. Here, we quantify the gain owing to such conditional randomized switching when the random variable has a generalized negative exponential distribution, and compare this to the optimal switching strategy. We also show that a randomized strategy may be advantageous when the distribution of the envelope's contents is unknown, since it can always lead to a gain.
19
Pandey, S., and V. K. Parnaik. "Identification of specific polypeptides of the nuclear envelope by iodination of mouse liver nuclei." Biochemical Journal 261, no. 3 (August 1, 1989): 733–38. http://dx.doi.org/10.1042/bj2610733.
Full textAbstract:
A sensitive technique is described for the rapid identification of nuclear-envelope proteins. Mouse liver nuclei (purified on sucrose gradients) were iodinated with Na125I by the immobilized water-insoluble reagent Iodogen. Iodinated nuclei were digested with RNAase A and DNAase I and then salt-extracted to obtain labelled nuclear envelopes. Nuclear envelopes were characterized by morphological and biochemical criteria and by SDS/polyacrylamide-gel electrophoresis. In all, 13 polypeptides of molecular masses 145, 115, 98, 85, 75, 70, 65, 54, 50, 45, 40, 38 and 36 kDa were identified in the labelled nuclear envelopes. The labelled polypeptides were localized to the nuclear envelope by extraction of the envelope with Triton X-100 and different concentrations of salt. Iodination of intact nuclei was shown to be specific for the nuclear envelope by the absence of labelling of histones and cytoplasmic contaminants.
20
Blaise, Sandra, Alessia Ruggieri, Marie Dewannieux, François-Loic Cosset, and Thierry Heidmann. "Identification of an Envelope Protein from the FRD Family of Human Endogenous Retroviruses (HERV-FRD) Conferring Infectivity and Functional Conservation among Simians." Journal of Virology 78, no. 2 (January 15, 2004): 1050–54. http://dx.doi.org/10.1128/jvi.78.2.1050-1054.2004.
Full textAbstract:
ABSTRACT A member of the HERV-W family of human endogenous retroviruses (HERV) had previously been demonstrated to encode a functional envelope which can form pseudotypes with human immunodeficiency virus type 1 virions and confer infectivity on the resulting retrovirus particles. Here we show that a second envelope protein sorted out by a systematic search for fusogenic proteins that we made among all the HERV coding envelope genes and belonging to the HERV-FRD family can also make pseudotypes and confer infectivity. We further show that the orthologous envelope genes that were isolated from simians—from New World monkeys to humans—are also functional in the infectivity assay, with one singular exception for the gibbon HERV-FRD gene, which is found to be fusogenic in a cell-cell fusion assay, as observed for the other simian envelopes, but which is not infectious. Sequence comparison of the FRD envelopes revealed a limited number of mutations among simians, and one point mutation—located in the TM subunit—was shown to be responsible for the loss of infectivity of the gibbon envelope. The functional characterization of the identified envelopes is strongly indicative of an ancestral retrovirus infection and endogenization, with some of the envelope functions subsequently retained in evolution.
21
Clark, Laura, Alexandra Dean, Alex Mitchell, and David J. Torgerson. "Envelope use and reporting in randomised controlled trials: A guide for researchers." Research Methods in Medicine & Health Sciences 2, no. 1 (October 13, 2020): 2–11. http://dx.doi.org/10.1177/2632084320957204.
Full textAbstract:
Introduction To produce robust evidence RCTs need to be rigorously conducted as poorly performed studies introduce bias and can mislead clinicians and policy makers. Poor allocation concealment has the largest single impact on bias in RCTs than other methodological aspects. Envelopes are frequently used as a method of allocation concealment and can be associated with increased risk of bias. This paper aims to review envelope use in RCTs published in 2017–2018 and create a guide as a reference for researchers when planning and publishing RCTs when using envelopes as an allocation concealment method. Methods RCTs that used envelopes as a form of allocation concealment that were published in BMJ, JAMA, NEJM and The Lancet in 2017 and 2018 were identified and methodological data on their envelope use extracted and authors were contacted to ascertain reasons for using envelopes in their research. Results 338 RCTs were identified that were published in 2017 and 2018. 8% (n = 29) of the RCTs published used envelopes as an allocation concealment method. 24.1% (n = 7) of studies reported envelope studies robustly with all required methodological information stated to enable an assessment of quality. Budget was the most frequent reason given for envelope use (41.7%). Discussion Only 24% of published RCTs, that used envelopes, contained robust methodological information to enable the reader to judge whether the randomisation and allocation concealment method was adequate. Conclusion RCTs are not reporting envelope use well. RCTs using envelopes should be designed and reported clearly ensuring all necessary methodological information is included.
22
Cocco, Massimo, and John Boatwright. "The envelopes of acceleration time histories." Bulletin of the Seismological Society of America 83, no. 4 (August 1, 1993): 1095–114. http://dx.doi.org/10.1785/bssa0830041095.
Full textAbstract:
Abstract We derive an analytical model for the envelope of the time history of the acceleration radiated by a dynamic rupture process. The critical element of the model is the stochastic assumption that the acceleration pulses radiated by different fault areas or by different sections of the rupture front arrive incoherently at any observer. The model for the resulting acceleration envelope depends on the square root of the line integral, evaluated over the isochrone, of the square of the product of the dynamic stress drop and a high-frequency radiation pattern that incorporates both directivity and diffraction. By evaluating the maximum of this envelope for simple rupture geometries, we predict the variation of peak acceleration with source size and recording bandwidth for earthquakes from ML ≈ −1 to 6. We also test the analytic model for the envelope using numerical sources that exhibit both smooth and rough rupture growth, fitting the acceleration envelopes of the rough rupture models slightly better than the envelopes of the smooth rupture models. Finally, we propose and test a deconvolutional technique that fits the squared acceleration envelope from a large earthquake as the sum of squared acceleration envelopes recorded from a small earthquake.
23
Bhattacharya, Jayanta, Paul J. Peters, and Paul R. Clapham. "Human Immunodeficiency Virus Type 1 Envelope Glycoproteins That Lack Cytoplasmic Domain Cysteines: Impact on Association with Membrane Lipid Rafts and Incorporation onto Budding Virus Particles." Journal of Virology 78, no. 10 (May 15, 2004): 5500–5506. http://dx.doi.org/10.1128/jvi.78.10.5500-5506.2004.
Full textAbstract:
ABSTRACT The human immunodeficiency virus type 1 (HIV-1) envelope comprises a surface gp120 and a transmembrane gp41. The cytoplasmic domain of gp41 contains cysteine residues (C764 and C837) which are targets for palmitoylation and were reported to be required for envelope association with lipid rafts and assembly on budding virions (I. Rousso, M. B. Mixon, B. K. Chen, and P. S. Kim, Proc. Natl. Acad. Sci. USA 97:13523-13525, 2000). Several infectious HIV-1 clones contain envelopes that have no gp41 cytoplasmic cysteines. Since no other gp41 amino acid is a target for palmitoylation, these clones imply that palmitoylation is not essential for envelope trafficking and assembly. Here, we show that HIV-1 envelope mutants that lack gp41 cytoplasmic cysteines are excluded from light lipid rafts. Envelopes that contained residues with bulky hydrophobic side chains instead of cysteines retained their association with heavy rafts and were nearly fully functional for incorporation into virions and infectivity. Substitution of cysteines with alanines or serines eliminated raft association and more severely reduced envelope incorporation onto virions and their infectivity. Nevertheless, the A764/A837 mutant envelope retained nearly 40% infectivity compared to the wild type, even though this envelope was excluded from lipid rafts. Our results demonstrate that gp41 cytoplasmic cysteines that are targets for palmitoylation and are required for envelope trafficking to classical lipid rafts are not essential for HIV-1 replication.
24
Ren, Zu Hua, and Bo Lin Wang. "Detection of Flicker Caused by Interharmonics Based on the Voltage Envelope Mean FFT." Applied Mechanics and Materials 325-326 (June 2013): 879–82. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.879.
Full textAbstract:
This paper introduces a detection algorithm of flicker caused by interharmonics based on the voltage envelope extraction and analysis. Whether the interharmonic frequency is near the odd or the even harmonics, the envelopes show different characteristics. The envelope mean is calculated accordingly and the relationship between the envelope mean and the flicker signal is analyzed in detail. It concludes that the flicker frequency and amplitude can be obtained accurately through FFT of the envelope mean and amplitude correction. Simulation results verify the algorithm.
25
Ge, Guang Tao. "Over-Sifting Components Analysis in Bidimensional Empirical Mode Decomposition." Advanced Materials Research 159 (December 2010): 377–82. http://dx.doi.org/10.4028/www.scientific.net/amr.159.377.
Full textAbstract:
Define the course of getting mean envelope as an operation (mean envelope operation) in Empirical mode decomposition (EMD), so as to express the Intrinsic Mode Function (IMF) with mean envelopes. Summarize several rules of the mean envelope operation. On this fundamental, the abnormal components exist in the over-sifting IMFs are extracted out, and the conclusion is testified with the infinite sifting experiment.
26
Millman, Rebecca E., Sam R. Johnson, and Garreth Prendergast. "The Role of Phase-locking to the Temporal Envelope of Speech in Auditory Perception and Speech Intelligibility." Journal of Cognitive Neuroscience 27, no. 3 (March 2015): 533–45. http://dx.doi.org/10.1162/jocn_a_00719.
Full textAbstract:
The temporal envelope of speech is important for speech intelligibility. Entrainment of cortical oscillations to the speech temporal envelope is a putative mechanism underlying speech intelligibility. Here we used magnetoencephalography (MEG) to test the hypothesis that phase-locking to the speech temporal envelope is enhanced for intelligible compared with unintelligible speech sentences. Perceptual “pop-out” was used to change the percept of physically identical tone-vocoded speech sentences from unintelligible to intelligible. The use of pop-out dissociates changes in phase-locking to the speech temporal envelope arising from acoustical differences between un/intelligible speech from changes in speech intelligibility itself. Novel and bespoke whole-head beamforming analyses, based on significant cross-correlation between the temporal envelopes of the speech stimuli and phase-locked neural activity, were used to localize neural sources that track the speech temporal envelope of both intelligible and unintelligible speech. Location-of-interest analyses were carried out in a priori defined locations to measure the representation of the speech temporal envelope for both un/intelligible speech in both the time domain (cross-correlation) and frequency domain (coherence). Whole-brain beamforming analyses identified neural sources phase-locked to the temporal envelopes of both unintelligible and intelligible speech sentences. Crucially there was no difference in phase-locking to the temporal envelope of speech in the pop-out condition in either the whole-brain or location-of-interest analyses, demonstrating that phase-locking to the speech temporal envelope is not enhanced by linguistic information.
27
Perekhozhentsev, Anatoliy Georgievich. "Perekhozhentsev A.G. Control of thermal resistance of building envelopes according to heat comfort in a premise." Vestnik MGSU, no. 2 (February 2016): 173–85. http://dx.doi.org/10.22227/1997-0935.2016.2.173-185.
Full textAbstract:
Setting standards of thermal resistance of building envelopes is a current task related with energy saving and energy efficiency of building envelopes. The problem of choosing the factor determining the standard thermal resistance also stays current even after updating of the Construction Norms. The author consider the concept of norming the thermal resistance of building envelope, in which the temperature of the inner surface of a building envelope providing comfortable temperature conditions in premises. The main task of an architect, who is designing an energy efficient building envelope is providing comfortable conditions in premises both in cold and warm periods of the year. The temperature of the inner surface of building envelopes should be included into the construction norms as the main criterion providing comfortable air temperature in premises.
28
Arthos, James, Andrea Rubbert, Ronald L. Rabin, Claudia Cicala, Elizabeth Machado, Kathryne Wildt, Meredith Hanbach, et al. "CCR5 Signal Transduction in Macrophages by Human Immunodeficiency Virus and Simian Immunodeficiency Virus Envelopes." Journal of Virology 74, no. 14 (July 15, 2000): 6418–24. http://dx.doi.org/10.1128/jvi.74.14.6418-6424.2000.
Full textAbstract:
ABSTRACT The capacity of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) envelopes to transduce signals through chemokine coreceptors on macrophages was examined by measuring the ability of recombinant envelope proteins to mobilize intracellular calcium stores. Both HIV and SIV envelopes mobilized calcium via interactions with CCR5. The kinetics of these responses were similar to those observed when macrophages were treated with MIP-1β. Distinct differences in the capacity of envelopes to mediate calcium mobilization were observed. Envelopes derived from viruses capable of replicating in macrophages mobilized relatively high levels of calcium, while envelopes derived from viruses incapable of replicating in macrophages mobilized relatively low levels of calcium. The failure to efficiently mobilize calcium was not restricted to envelopes derived from CXCR4-utilizing isolates but also included envelopes derived from CCR5-utilizing isolates that fail to replicate in macrophages. We characterized one CCR5-utilizing isolate, 92MW959, which entered macrophages but failed to replicate. A recombinant envelope derived from this virus mobilized low levels of calcium. When macrophages were inoculated with 92MW959 in the presence of MIP-1α, viral replication was observed, indicating that a CC chemokine-mediated signal provided the necessary stimulus to allow the virus to complete its replication cycle. Although the role that envelope-CCR5 signal transduction plays in viral replication is not yet understood, it has been suggested that envelope-mediated signals facilitate early postfusion events in viral replication. The data presented here are consistent with this hypothesis and suggest that the differential capacity of viral envelopes to signal through CCR5 may influence their ability to replicate in macrophages.
29
Nierzwicki-Bauer, S. A., H. Aulfinger, and E. B. Braun-Howland. "Ultrastructural characterization of an inner envelope that confines Azolla endosymbionts to the leaf cavity periphery." Canadian Journal of Botany 67, no. 9 (September 1, 1989): 2711–19. http://dx.doi.org/10.1139/b89-349.
Full textAbstract:
Ultrastructural characteristics of Azolla leaf cavities were examined using transmission electron microscopy. An extracellular inner envelope, which forms a boundary between the central cavity region and the peripheral region containing cyanobacteria and (or) bacteria, was found in all closed leaf cavities of symbiotic and Anabaena-free Azolla species. In the youngest leaf, which is in the process of developing a cavity, a continuous inner envelope was never observed. However, in young leaves that contained closed cavities, and in older leaves, continuous inner envelopes were always observed. The inner envelope may serve to restrict the symbionts to the cavity periphery. The inner envelope was similar in appearance to the outer envelope, which encloses the symbionts and hair cells within leaf cavities. Examination of the inner envelope using three different fixation procedures revealed that it was most distinct in fronds fixed in potassium permanganate, suggesting that it is membranelike in structure. The envelope was occasionally seen folded back upon itself or curled, which is also characteristic of a membranelike structure. Nevertheless, the envelope did not exhibit typical tripartite membrane ultrastructure. The occurrence of the inner envelope in Anabaena-free Azolla indicates that this envelope is of eubacterial or plant origin.
30
Huang, Bingyao, Ruyi Lian, Dimitris Samaras, and Haibin Ling. "Modeling Deep Learning Based Privacy Attacks on Physical Mail." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 2 (May 18, 2021): 1593–601. http://dx.doi.org/10.1609/aaai.v35i2.16251.
Full textAbstract:
Mail privacy protection aims to prevent unauthorized access to hidden content within an envelope since normal paper envelopes are not as safe as we think. In this paper, for the first time, we show that with a well designed deep learning model, the hidden content may be largely recovered without opening the envelope. We start by modeling deep learning-based privacy attacks on physical mail content as learning the mapping from the camera-captured envelope front face image to the hidden content, then we explicitly model the mapping as a combination of perspective transformation, image dehazing and denoising using a deep convolutional neural network, named Neural-STE (See-Through-Envelope). We show experimentally that hidden content details, such as texture and image structure, can be clearly recovered. Finally, our formulation and model allow us to design envelopes that can counter deep learning-based privacy attacks on physical mail.
31
Husebye, Eystein S., Bent O. Ruud, and Anton M. Dainty. "Robust and reliable epicenter determinations: Envelope processing of local network data." Bulletin of the Seismological Society of America 88, no. 1 (February 1, 1998): 284–90. http://dx.doi.org/10.1785/bssa0880010284.
Full textAbstract:
Abstract Local event recordings are complex in the sense that relevant P and S phases vary in an unpredictable manner even between closely spaced stations; thus, manual analysis of such records is still commonplace. Our approach to solving this long-standing problem of observational seismology is to bandpass filter (3 to 6 Hz) to ensure good signal-to-noise ratio SNR and then form envelopes to ensure simple signals across a seismograph network. The physical basis is that Pg and Lg are crustal wave-guide phases reflecting P- and S-energy propagation. Extensive tests on envelope analysis of local records from different areas found that arrival times of the maxima of Pg and Lg envelopes increase very consistently with distance even in different tectonic regimes, typical velocities being 6.1 and 3.5 km/sec, respectively. These arrival-time parameters are easy to extract in a semi-automatic manner and are highly suitable for local epicenter determinations. Extensive tests on locating mining explosions were conducted, and on average, the “envelope” location errors relative to “true” locations were similar to those in bulletins that are based on conventional phase pickings. Occasionally, the Pg/Pn envelope may be very weak but can be replaced by the easily pickable (non-envelope) Pn phase. Additional advantages with envelope locations are transportability (not overly sensitive to details of crustal structure), and that envelope amplitudes can be directly converted to ground motion and magnitudes. For modern stations, envelopes can be formed in situ with low sampling rates of 1 to 2 Hz, thus greatly reducing transmission costs.
32
Chiradeja, Pathomthat, and Atthapol Ngaopitakkul. "Energy and Economic Analysis of Tropical Building Envelope Material in Compliance with Thailand’s Building Energy Code." Sustainability 11, no. 23 (December 3, 2019): 6872. http://dx.doi.org/10.3390/su11236872.
Full textAbstract:
The building envelope has a direct impact on the overall energy consumption of a building. Thus, an improvement in the building envelope using energy-efficient material can yield the desired energy performance. This study is based on the materials and compositions used in building envelopes in compliance with the building energy code of Thailand. The building under study is an educational building located in Bangkok, Thailand. Both the energy and the economic aspects of retrofitted building envelopes are discussed in this study. The energy performance was evaluated by calculating the thermal transfer value and whole building energy consumption using the building energy code (BEC) software. The simulation was done under the assumption that the building envelope in the case study building was retrofitted with different materials and compositions. The study determines the feasibility of retrofitting buildings using energy-efficient material by utilizing the discounted payback period and internal rate of return (IRR) as indicators. The results show that retrofitted building envelopes in every case can reduce the whole building energy consumption. In the best envelope configuration, energy consumption can decrease by 65%. In addition, the economic potential is also high, with an IRR value of approximately 15% and a payback period of 23 less than nine years. These finding indicate that a building envelope made with energy-efficient material can achieve good results for both energy performance and economic feasibility.
33
Galametz, Maud, Anaëlle Maury, Josep M. Girart, Ramprasad Rao, Qizhou Zhang, Mathilde Gaudel, Valeska Valdivia, et al. "An observational correlation between magnetic field, angular momentum and fragmentation in the envelopes of Class 0 protostars?" Astronomy & Astrophysics 644 (December 2020): A47. http://dx.doi.org/10.1051/0004-6361/202038854.
Full textAbstract:
Aims. The main goal of the following analysis is to assess the potential role of magnetic fields in regulating the envelope rotation, the formation of disks and the fragmentation of Class 0 protostars in multiple systems. Methods. We use the Submillimeter Array to carry out observations of the dust polarized emission at 0.87 mm, in the envelopes of a large sample of 20 Class 0 protostars. We estimate the mean magnetic field orientation over the central 1000 au envelope scales to characterize the orientation of the main component of the organized magnetic field at the envelope scales in these embedded protostars. This direction is compared to that of the protostellar outflow in order to study the relation between their misalignment and the kinematics of the circumstellar gas. The latter is traced via velocity gradient observed in the molecular line emission (mainly N2H+) of the gas at intermediate envelope scales. Results. We discover a strong relationship between the misalignment of the magnetic field orientation with the outflow and the amount of angular momentum observed at similar scales in the protostellar envelope, revealing a potential link between the kinetic and the magnetic energy at envelope scales. The relation could be driven by favored B-misalignments in more dynamical envelopes or a dependence of the envelope dynamics with the large-scale B initial configuration. Comparing the trend with the presence of fragmentation, we observe that single sources are mostly associated with conditions of low angular momentum in the inner envelope and good alignment of the magnetic field with protostellar outflows, at intermediate scales. Our results suggest that the properties of the magnetic field in protostellar envelopes bear a tight relationship with the rotating-infalling gas directly involved in the star and disk formation: we find that it may not only influence the fragmentation of protostellar cores into multiple stellar systems, but also set the conditions establishing the pristine properties of planet-forming disks.
34
Uheda, Eiji, and Shunji Kitoh. "Electron microscopic observations of the envelopes of isolated algal packets of Azolla." Canadian Journal of Botany 69, no. 7 (July 1, 1991): 1418–19. http://dx.doi.org/10.1139/b91-183.
Full textAbstract:
The envelopes of isolated algal packets from cyanobiont-containing and cyanobiont-free Azolla were examined with the electron microscope. Both types of envelope were 10–20 nm thick and composed of three layers. The three-layer structure was also observed when algal packets were treated with cellulase, pectinase, lipase, protease, sodium hydroxide, nitric acid, or sodium dodecylsulfate. Thus, the envelopes do not appear to be membrane-like in nature and the presence and ultrastructure of the envelopes are not affected by cyanobiont filaments. Key words: algal packet, cyanobiont-free Azolla, Azolla, electron microscopic studies, envelope.
35
Wang, Li Jun, Xiao Ping Miao, Rui Hai Wang, and Bo Wang. "Numerical Simulation on Heat Transfer from Envelope of the Underground Engineering." Advanced Materials Research 320 (August 2011): 657–62. http://dx.doi.org/10.4028/www.scientific.net/amr.320.657.
Full textAbstract:
Whether the results of the dynamic heat flux from the underground engineering envelope are accurate, may influence the accuracy of calculating the transient heat load and could affect the initial cost and actual operation of the air conditioning system in the underground engineering. Based on the mathematical modeling of heat transfer in the underground engineering envelope, the influence of the model dimension, boundary condition on the soil surface, initial temperature of the soil, the adiabatic distances far from the envelope and the heat transfer coefficient between the envelope surface and the indoor air, the heat transfer mechanism of the underground engineering envelope was studied in terms of the building structure, style of the envelopes and the difference of the locations. For providing the analysis basis to simplified calculation of heat transfer in the underground engineering envelope.
36
Oterino, J., G. Sánchez Toranzo, L. Zelarayán, M. T. Ajmat, F. Bonilla, and M. I. Bühler. "Behaviour of the vitelline envelope in Bufo arenarum oocytes matured in vitro in blockade to polyspermy." Zygote 14, no. 2 (May 2006): 97–106. http://dx.doi.org/10.1017/s0967199406003662.
Full textAbstract:
SummaryDuring activation of amphibian eggs, cortical granule exocytosis causes elaborate ultrastructural changes in the vitelline envelope. These changes involve modifications in the structure of the vitelline envelope and formation of a fertilization envelope (FE) that can no longer be penetrated by sperm. In Bufo arenarum, as the egg traverses the oviduct, the vitelline envelope is altered by a trypsin-like protease secreted by the oviduct, which induces an increased susceptibility of the vitelline envelope to sperm lysins. Full-grown oocytes of B. arenarum, matured in vitro by progesterone, are polyspermic, although cortical granule exocytosis seems to occur within a normal chronological sequence. These oocytes can be fertilized with or without trypsin treatment, suggesting that the vitelline envelope is totally sperm-permeable. Vitelline envelopes without trypsin treatment cannot retain either gp90 or gp96. This suggests that these glycoproteins are involved in the block to polyspermy and that trypsin treatment of matured in vitro oocytes before insemination is necessary to enable vitelline envelopes to block polyspermy. The loss of the binding capacity in vitelline envelopes isolated from B. arenarum oocytes matured in vitro with trypsin treatment and activated by electric shock suggests that previous trypsin treatment is a necessary step for sperm block to occur. When in vitro matured oocytes were incubated with the product of cortical granules obtained from in vitro matured oocytes (vCGP), vitelline envelopes with trypsin treatment were able to block sperm entry. These oocytes exhibited the characteristic signs of activation. These results support the idea that B. arenarum oocytes can be activated by external stimuli and suggest the presence of unknown oocyte surface receptors linked to the activation machinery in response to fertilization. Electrophoretic profiles obtained by SDS-PAGE of solubilized vitelline envelopes from oocytes matured in vitro revealed the conversion of gp40 (in vitro matured oocytes, without trypsin treatment) to gp38 (ascribable to trypsin activity or cortical granule product activity, CGP) and the conversion of gp70 to gp68 (ascribable to trypsin activity plus CGP activity). Taking into account that only the vitelline envelopes of in vitro matured oocytes with trypsin treatment and activated can block sperm entry, we may suggest that the conversion of gp70 to gp68 is related to the changes associated with sperm binding.
37
Volkov, Victor, and Carole C. Perry. "Modeling of Infrared–Visible Sum Frequency Generation Microscopy Images of a Giant Liposome." Microscopy and Microanalysis 22, no. 6 (October 27, 2016): 1128–45. http://dx.doi.org/10.1017/s1431927616011752.
Full textAbstract:
AbstractThe article explores the theory of infrared–visible sum frequency generation microscopy of phospholipid envelopes with dimensions larger than the wavelength of the nonlinear emission. The main part of the study concerns derivation and accounting for the contributions of effective nonlinear responses specific to sites on the surfaces of a bilayer envelope and their dependence on polarization condition and experimental geometry. The nonlinear responses of sites are mapped onto the image plane according to their emission directions and the numerical aperture of a sampling microscope objective. According to the simulation results, we discuss possible approaches to characterize the shape of the envelope, to extract molecular hyperpolarizabilities, and to anticipate possible heterogeneity in envelope composition and anisotropy of the environment proximal to the envelope. The modeling approach offers a promising analytic facility to assist connecting microscopy observations in engineered liposomes, cellular envelopes, and subcellular organelles of relatively large dimensions to molecular properties, and hence to chemistry and structure down to available spatial resolution.
38
Baikie, L. D. "Casagrande resistance envelopes for rock and rockfill slopes having circular slip surfaces." Canadian Geotechnical Journal 25, no. 1 (February 1, 1988): 42–49. http://dx.doi.org/10.1139/t88-005.
Full textAbstract:
A series of Casagrande resistance envelopes are presented for use in the preliminary design and evaluation of uniform rock and rockfill slopes. The influence of tension cracks on the safety factors for such slopes is examined. A comparison is also made between the safety factors obtained using the resistance envelope method and those obtained using published stability charts for rockfill slopes having nonlinear shear strength envelopes. Key words: rock, rockfill, slope, stability, Casagrande resistance envelope, safety factor.
39
Whytock, S., R. D. Moir, and M. Stewart. "Selective digestion of nuclear envelopes from Xenopus oocyte germinal vesicles: possible structural role for the nuclear lamina." Journal of Cell Science 97, no. 3 (November 1, 1990): 571–80. http://dx.doi.org/10.1242/jcs.97.3.571.
Full textAbstract:
We have used enzymic digestion as a structural probe to investigate components of the nuclear envelope of germinal vesicles from Xenopus oocytes. Previous studies have shown that these envelopes are composed of a double membrane in which nuclear pore complexes are embedded. The nuclear pore complexes are linked to a fibrous lamina that underlies the nucleoplasmic face of the envelope. The pores are also linked by pore-connecting fibrils that attach near their cytoplasmic face. Xenopus oocyte nuclear envelopes were remarkably resistant to extraction with salt solutions and, even after treatment with 1 M NaCl or 3 M MgCl2, pores, lamina and pore-connecting fibrils remained intact. However, mild proteolysis with trypsin selectively removed the lamina fibres from Triton-extracted nuclear envelopes to leave only the pore complexes and connecting fibrils. This observation confirmed that the pore-connecting fibrils were different from the lamina fibres and were probably constructed from different proteins. Trypsin digestion followed by Triton treatment resulted in the complete disintegration of the nuclear envelope, providing direct evidence for a structural role for the lamina in maintaining envelope integrity. Digestion with ribonuclease did not produce any marked change in the structure of Triton-extracted nuclear envelopes, indicating that probably neither the pore-connecting fibrils nor the cytoplasmic granules on the pore complexes contained a substantial proportion of RNA that was vital for their structural integrity.
40
Pastore, Cristina, Rebecca Nedellec, Alejandra Ramos, Oliver Hartley, John L. Miamidian, Jacqueline D. Reeves, and Donald E. Mosier. "Conserved Changes in Envelope Function during Human Immunodeficiency Virus Type 1 Coreceptor Switching." Journal of Virology 81, no. 15 (May 16, 2007): 8165–79. http://dx.doi.org/10.1128/jvi.02792-06.
Full textAbstract:
ABSTRACT We studied the evolution of human immunodeficiency virus type 1 (HIV-1) envelope function during the process of coreceptor switching from CCR5 to CXCR4. Site-directed mutagenesis was used to introduce most of the possible intermediate mutations in the envelope for four distinct coreceptor switch mutants, each with a unique pattern of CCR5 and CXCR4 utilization that extended from highly efficient use of both coreceptors to sole use of CXCR4. Mutated envelopes with some preservation of entry function on either CCR5- or CXCR4-expressing target cells were further characterized for their sensitivity to CCR5 or CXCR4 inhibitors, soluble CD4, and the neutralizing antibodies b12-IgG and 4E10. A subset of mutated envelopes was also studied in direct CD4 or CCR5 binding assays and in envelope-mediated fusion reactions. Coreceptor switch intermediates displayed increased sensitivity to CCR5 inhibitors (except for a few envelopes with mutations in V2 or C2) that correlated with a loss in CCR5 binding. As use of CXCR4 improved, infection mediated by the mutated envelopes became more resistant to soluble CD4 inhibition and direct binding to CD4 increased. These changes were accompanied by increasing resistance to the CXCR4 inhibitor AMD3100. Sensitivity to neutralizing antibody was more variable, although infection of CXCR4-expressing targets was generally more sensitive to neutralization by both b12-IgG and 4E10 than infection of CCR5-expressing target cells. These changes in envelope function were uniform in all four series of envelope mutations and thus were independent of the final use of CCR5 and CXCR4. Decreased CCR5 and increased CD4 binding appear to be common features of coreceptor switch intermediates.
41
KRSTIĆ, DRAGANA, SUAD SULJOVIĆ, MIHAJLO STEFANOVIĆ, MUNEER MASADEH BANI YASSEIN, and DANIJELA ALEKSIĆ. "New Results and Applications about the Level Crossing Rate of SC Receiver output Signal in the Presence of Gamma Shadowing and k-μ or Rician Multipath Fading." WSEAS TRANSACTIONS ON CIRCUITS AND SYSTEMS 20 (June 28, 2021): 118–27. http://dx.doi.org/10.37394/23201.2021.20.15.
Full textAbstract:
In this paper,the wireless communication system with dual SC receiver operating over shadowed multipath fading channel is considered. The multipath fadingis k-μor Rician.The received signal experiences the short term fading which is resulting in SC receiver envelope variation and Gamma long term fading resulting in SC receiver envelope power variation. The closed form expressions for joint probability density functions of SC receiver output signal envelope and their first derivative of SC receiver output signal envelope are calculated for both, k-μand Rician fading. These expressions are used for evaluation of average level crossing rate of SC receiver output signal envelopes. The numerical expressions are plotted to show the effect of Rician fading severity parameter and Gamma shadowing severity parameter on the average level crossing rate of SC receiver output signal envelope.
42
Luo, Taiming, and Alexei Yu Chirkov. "PHASE ENVELOPE CONSTRUCTION FOR MIXTURES USING HIGHLY ACCURATE HELMHOLTZ ENERGY EQUATION OF STATE." Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy 6, no. 4 (2020): 8–27. http://dx.doi.org/10.21684/2411-7978-2020-6-4-8-27.
Full textAbstract:
Phase envelope construction for mixtures is very important in the oil and gas industry. The most widely used model for phase envelope construction is Peng — Robinson equation of state (PR-EOS) due to its simplicity. In order to construct phase envelopes of natural gas, a highly accurate Helmholtz energy equation of state GERG-2008 was proposed. In this work, the accuracy of phase envelopes calculated by a highly accurate equation of state GERG-2008, simplified GERG-2008 and traditional cubic PR-EOS was analyzed. The pressure-based algorithm is used to calculate phase envelopes. Phase envelopes of the methane—ethane mixtures were constructed and compared with reference data. The results show that phase envelopes can be constructed with GERG-2008 in high accuracy. PR-EOS has good accuracy in phase envelope construction under low pressure. The simplified GERG-2008 also works well under low pressure; however, as pressure increases, it performs worse than the simpler PR-EOS, especially in the vicinity of critical point. Besides, a modified density solver for the complicated GERG-EOS was proposed. Calculations show that the proposed density solver can provide reliable results.
43
Hyllner, S. J., and C. Haux. "Immunochemical detection of the major vitelline envelope proteins in the plasma and oocytes of the maturing female rainbow trout, Oncorhynchus mykiss." Journal of Endocrinology 135, no. 2 (November 1992): 303—NP. http://dx.doi.org/10.1677/joe.0.1350303.
Full textAbstract:
ABSTRACT The major vitelline envelope proteins were detected in the plasma of female rainbow trout maturing under natural conditions by using the Western blot technique. Females were sampled every month from July until ovulation in January. The amount of vitelline envelope proteins in plasma increased markedly as the gonads increased in size from 0·4 to about 15% of the total body weight. The plasma level of oestradiol-17β largely followed the alterations in the amount of vitelline envelope proteins, indicating the endocrine control of vitelline envelope protein synthesis. In addition, plasma vitellogenin changed in a manner that resembled the changes in the amount of plasma vitelline envelope proteins. The appearance and growth of the vitelline envelope during oocyte development was demonstrated using immunohistochemical methods. The vitelline envelopes from oocytes at different stages of development were immunoreactive with the antibodies directed against the major vitelline envelope proteins. No immunoreactivity could be observed in the ooplasm or in the surrounding follicular cells, which indicated that the major vitelline envelope proteins were of extraovarian origin. The present study further supports the hypothesis that the major protein constituents of the vitelline envelope in teleosts are under the endocrine control of oestradiol17β and that the site of synthesis is outside the ovary. Journal of Endocrinology (1992) 135, 303–309
44
Kelly, Amélie A., Barbara Kalisch, Georg Hölzl, Sandra Schulze, Juliane Thiele, Michael Melzer, Rebecca L. Roston, Christoph Benning, and Peter Dörmann. "Synthesis and transfer of galactolipids in the chloroplast envelope membranes of Arabidopsis thaliana." Proceedings of the National Academy of Sciences 113, no. 38 (September 6, 2016): 10714–19. http://dx.doi.org/10.1073/pnas.1609184113.
Full textAbstract:
Galactolipids [monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG)] are the hallmark lipids of photosynthetic membranes. The galactolipid synthases MGD1 and DGD1 catalyze consecutive galactosyltransfer reactions but localize to the inner and outer chloroplast envelopes, respectively, necessitating intermembrane lipid transfer. Here we show that the N-terminal sequence of DGD1 (NDGD1) is required for galactolipid transfer between the envelopes. Different diglycosyllipid synthases (DGD1, DGD2, and Chloroflexus glucosyltransferase) were introduced into the dgd1-1 mutant of Arabidopsis in fusion with N-terminal extensions (NDGD1 and NDGD2) targeting to the outer envelope. Reconstruction of DGDG synthesis in the outer envelope membrane was observed only with diglycosyllipid synthase fusion proteins carrying NDGD1, indicating that NDGD1 enables galactolipid translocation between envelopes. NDGD1 binds to phosphatidic acid (PA) in membranes and mediates PA-dependent membrane fusion in vitro. These findings provide a mechanism for the sorting and selective channeling of lipid precursors between the galactolipid pools of the two envelope membranes.
45
Howe, Laryssa, Caroline Leroux, Charles J. Issel, and Ronald C. Montelaro. "Equine Infectious Anemia Virus Envelope Evolution In Vivo during Persistent Infection Progressively Increases Resistance to In Vitro Serum Antibody Neutralization as a Dominant Phenotype." Journal of Virology 76, no. 21 (November 1, 2002): 10588–97. http://dx.doi.org/10.1128/jvi.76.21.10588-10597.2002.
Full textAbstract:
ABSTRACT Equine infectious anemia virus (EIAV) infection of horses is characterized by well-defined waves of viremia associated with the sequential evolution of distinct viral populations displaying extensive envelope gp90 variation; however, a correlation of in vivo envelope evolution with in vitro serum neutralization phenotype remains undefined. Therefore, the goal of the present study was to utilize a previously defined panel of natural variant EIAV envelope isolates from sequential febrile episodes to characterize the effects of envelope variation during persistent infection on viral neutralization phenotypes and to define the determinants of EIAV envelope neutralization specificity. To assess the neutralization phenotypes of the sequential EIAV envelope variants, we determined the sensitivity of five variant envelopes to neutralization by a longitudinal panel of immune serum from the source infected pony. The results indicated that the evolution of the EIAV envelope sequences observed during sequential febrile episodes produced an increasingly neutralization-resistant phenotype. To further define the envelope determinants of EIAV neutralization specificity, we examined the neutralization properties of a panel of chimeric envelope constructs derived from reciprocal envelope domain exchanges between selected neutralization-sensitive and neutralization-resistant envelope variants. These results indicated that the EIAV gp90 V3 and V4 domains individually conferred serum neutralization resistance while other envelope segments in addition to V3 and V4 were evidently required for conferring total serum neutralization sensitivity. These data clearly demonstrate for the first time the influence of sequential gp90 variation during persistent infection in increasing envelope neutralization resistance, identify the gp90 V3 and V4 domains as the principal determinants of antibody neutralization resistance, and indicate distinct complex cooperative envelope domain interactions in defining sensitivity to serum antibody neutralization.
46
Lavillette, Dimitri, Alessia Ruggieri, Stephen J. Russell, and François-Loïc Cosset. "Activation of a Cell Entry Pathway Common to Type C Mammalian Retroviruses by Soluble Envelope Fragments." Journal of Virology 74, no. 1 (January 1, 2000): 295–304. http://dx.doi.org/10.1128/jvi.74.1.295-304.2000.
Full textAbstract:
ABSTRACT Mutations that negatively or positively affect the fusion properties of murine leukemia viruses (MLVs) have been found within all subdomains of their SU (surface) and TM (transmembrane) envelope units. Yet, the interrelations between these different regions of the envelope complex during the cell entry process are still elusive. Deletion of the histidine residue of the conserved PHQV motif at the amino terminus of the amphotropic or the ecotropic MLV SU resulted in the AdelH or the MOdelH fusion-defective mutant envelope, respectively. These delH mutant envelopes are incorporated on retroviral particles at normal densities and normally mediate virion binding to cells expressing the retroviral receptors. However, both their cell-cell and virus-cell fusogenicities were fully prevented at an early postbinding stage. We show here that the fusion defect of AdelH or MOdelH envelopes was also almost completely reverted by providing either soluble SU or a polypeptide encompassing the receptor-binding domain (RBD) to the target cells, provided that the integrity of the amino-terminal end of either polypeptide was preserved. Restoration of delH envelope fusogenicity was caused by activation of the target cells via specific interaction of the latter polypeptides with the retrovirus receptor rather than by their association with the delH envelope complexes. Moreover crossactivation of the target cells, leading to fusion activation of AdelH or MOdelH envelopes, was achieved by polypeptides containing various type C mammalian retrovirus RBDs, irrespective of the type of entry-defective glycoprotein that was used for infection. Our results indicate that although they recognize different receptors for binding to the cell surface, type C mammalian retroviruses use a common entry pathway which is activated by a conserved feature of their envelope glycoproteins.
47
Dharmasaroja, A., C. G. Armstrong, A. Murphy, T. T. Robinson, N. L. Iorga, and J. R. Barron. "Structural performance envelopes in load space." Aeronautical Journal 125, no. 1283 (November 17, 2020): 127–50. http://dx.doi.org/10.1017/aer.2020.94.
Full textAbstract:
ABSTRACTVisualising the loads that a structure can tolerate provides a key insight into the structural design process, especially for materials and structures that are governed by complex failure criteria. This paper proposes a general method for efficient construction of performance envelopes in load space, and demonstrates the approach with two examples. The performance envelope identifies all possible failure modes, all the redundant and non-redundant structural constraints, and the limiting failure mode in a particular direction in load space. Once the envelope has been constructed, the structural reserve factors can be calculated extremely quickly. In design such envelopes are most useful for structural analysis processes which involve a very large number of load cases, and where the cost of constructing an envelope for a given feature is relatively modest.
48
Federman, Samuel, S. Thomas Megeath, John J. Tobin, Patrick D. Sheehan, Riwaj Pokhrel, Nolan Habel, Amelia M. Stutz, et al. "300: An ACA 870 μm Continuum Survey of Orion Protostars and Their Evolution." Astrophysical Journal 944, no. 1 (February 1, 2023): 49. http://dx.doi.org/10.3847/1538-4357/ac9f4b.
Full textAbstract:
Abstract We present an 870 μm continuum survey of 300 protostars from the Herschel Orion Protostar Survey using the Atacama Compact Array (ACA). These data measure protostellar flux densities on envelope scales ≤8000 au (20″) and resolve the structure of envelopes with 1600 au (4″) resolution, a factor of 3–5 improvement in angular resolution over existing single-dish 870 μm observations. We compare the ACA observations to Atacama Large Millimeter/submillimeter Array 12 m array observations at 870 μm with ∼0.″1 (40 au) resolution. Using the 12 m data to measure the fluxes from disks and the ACA data within 2500 au to measure the combined disk plus envelope fluxes, we calculate the 12 m/ACA 870 μm flux ratios. Our sample shows a clear evolution in this ratio. Class 0 protostars are mostly envelope-dominated with ratios <0.5. In contrast, Flat Spectrum protostars are primarily disk-dominated with ratios near 1, although with a number of face-on protostars dominated by their envelopes. Class I protostars span the range from envelope to disk-dominated. The increase in ratio is accompanied by a decrease in the envelope fluxes and estimated mass infall rates. We estimate that 80% of the mass is accreted during the envelope-dominated phase. We find that the 12 m/ACA flux ratio is an evolutionary indicator that largely avoids the inclination and foreground extinction dependence of spectral energy distribution-based indicators.
49
Petrova, T. E., V. Y. Lunin, and A. D. Podjarny. "A likelihood-based search for the macromolecular position in the crystalline unit cell." Acta Crystallographica Section A Foundations of Crystallography 55, no. 4 (July 1, 1999): 739–45. http://dx.doi.org/10.1107/s0108767399001890.
Full textAbstract:
The goal of this work is to analyse whether the generalized likelihood criterion can be used to find the best spherical envelope of a macromolecule in a unit cell. A family of spherical envelopes is ranged in accordance with their likelihood values calculated by means of a Monte Carlo-type computer procedure. Two kinds of envelope families were tested. The first one was composed of spherical envelopes of fixed radius but different positions in the unit cell. In the second case, the sphere radii were linked to their centre position so that the total volume occupied by all symmetry-related spheres was roughly equal to the total volume occupied by the real molecule. The experiments showed that when using the first type of envelope the level of the signal for the right solution is higher than the one obtained with the straightforward R-factor-based single-Gaussian-atom search, but spurious maxima (usually placed on the symmetry axes) may still exist. The use of the second type of envelope family reduces the level of the spurious maxima.
50
Kemp, S. N., Víctor Hugo Ramírez-Siordia, and Ernesto Pérez-Hernández. "The intriguing life of cD galaxies." Proceedings of the International Astronomical Union 8, S295 (August 2012): 313. http://dx.doi.org/10.1017/s1743921313005152.
Full textAbstract:
cD galaxies are supergiant elliptical galaxies found generally in the central parts of rich clusters, which have an extended halo-like component (envelope) in addition to the underlying de Vaucouleurs-Sérsic elliptical galaxy-like component. This envelope can extend to radial distances of > 500 kpc (Oemler 1976, Schombert 1988). There have been many theories to explain the formation of these envelopes. These include tidal stripping, where material is stripped from neighbouring galaxies; mergers and fusions, where the envelope is built up hierarchically by successive mergers with large and small galaxies; primordial origin, where the envelope is formed at the same time as the rest of the elliptical galaxy (which appears to be related to theories of early formation of the largest galaxies); and cooling flows: in clusters with X-ray emission there is often a minimum temperature in the centre interpreted as a flow of cooling gas towards the centre of the cluster, where the gas can cool sufficiently, forming stars. The colours of the stars in the envelopes will be affected by their process of formation and subsequent evolution.