Location of Negative Charge Associated with Continuing Current of Upward Lightning Flash in Winter

Abstract Relationships between lightning flashes and thunderstorm kinematics and microphysics are important for applications such as nowcasting of convective intensity. These relationships are influenced by cloud electrification structures and have been shown to vary in anomalously electrified thunderstorms. This study addresses transitional relationships between active charge structure and lightning flash location in the context of kinematic and microphysical updraft characteristics during the development of an anomalously electrified supercell thunderstorm in the Tennessee Valley on 10 April 2009. The initial charge structure within the updraft was characterized as an anomalous dipole in which positive charge was inferred in regions of precipitation ice (i.e., graupel and hail) and negative charge was inferred in regions of cloud ice (i.e., aggregates and ice crystals). During subsequent development of the anomalous charge structure, additional minor charge layers as well as evidence of increasing horizontal complexity were observed. Microphysical and kinematic characteristics of the charge structure also evolved to include increasing observations of negative charge in precipitation ice regions, indicating the emergence of more prominent normal charging alongside dominant anomalous charging. Simultaneously, lightning flash initiation locations were also increasingly observed in regions of faster updrafts and stronger horizontal gradients in updraft speed. It is suggested that continuous variability in charging behavior over meso-gamma spatial scales influenced the evolution of lightning flash locations with respect to the updraft structure. Further work is necessary to determine how this variability may impact lightning flash relation-ships, including lightning flash rate, with bulk microphysical and kinematic characteristics and related applications.

Download Full-text

Evolving Complex Electrical Structures of the STEPS 25 June 2000 Multicell Storm

Monthly Weather Review ◽

10.1175/2007mwr2023.1 ◽

2008 ◽

Vol 136 (2) ◽

pp. 741-756 ◽

Cited By ~ 38

Author(s):

Stephanie A. Weiss ◽

W. David Rust ◽

Donald R. MacGorman ◽

Eric C. Bruning ◽

Paul R. Krehbiel

Keyword(s):

Great Plains ◽

Negative Charge ◽

Positive Charge ◽

Three Dimensional ◽

Lightning Flash ◽

Severe Thunderstorm ◽

Electrical Structure ◽

High Reflectivity ◽

Maximum Value ◽

Mapping Array

Abstract Data from a three-dimensional lightning mapping array (LMA) and from two soundings by balloon-borne electric field meters (EFMs) were used to analyze the electrical structures of a multicell storm observed on 25 June 2000 during the Severe Thunderstorm Electrification and Precipitation Study (STEPS). This storm had a complex, multicell structure with four sections, each of whose electrical structure differed from that of the others during all or part of the analyzed period. The number of vertically stacked charge regions in any given section of the storm ranged from two to six. The most complex charge and lightning structures occurred in regions with the highest reflectivity values and the deepest reflectivity cores. Intracloud flashes tended to concentrate in areas with large radar reflectivity values, though some propagated across more than one core of high reflectivity or into the low-reflectivity anvil. Intracloud lightning flash rates decreased as the vertical extent and maximum value of reflectivity cores decreased. Cloud-to-ground flash rates increased as cores of high reflectivity descended to low altitudes. Most cloud-to-ground flashes were positive. All observed positive ground flashes initiated between the lowest-altitude negative charge region and a positive charge region just above it. The storm’s complexity makes it hard to classify the vertical polarity of its overall charge structure, but most of the storm had a different vertical polarity than what is typically observed outside the Great Plains. The electrical structure can vary considerably from storm to storm, or even within the same storm, as in the present case.

Download Full-text

Observations of lightning in relation to transitions in volcanic activity during the 3 June 2018 Fuego Eruption

Scientific Reports ◽

10.1038/s41598-020-74576-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Christopher J. Schultz ◽

Virginia P. Andrews ◽

Kimberly D. Genareau ◽

Aaron R. Naeger

Keyword(s):

Negative Charge ◽

Volcanic Eruptions ◽

Potential Interaction ◽

Volcanic Plume ◽

Density Current ◽

Lightning Flash ◽

Optical Energy ◽

Multiple Frequencies ◽

Flash Spectrum ◽

Total Lightning

Abstract Satellite and ground-based remote sensing are combined to characterize lightning occurrence during the 3 June 2018 Volcán de Fuego eruption in Guatemala. The combination of the space-based Geostationary Lightning Mapper (GLM) and ground-based Earth Networks Total Lightning Network observed two distinct periods of lightning during this eruption totaling 75 unique lightning flash occurrences over five hours (57 in cloud, 18 cloud-to-ground). The first period of lightning coincided with the rapid growth of the ash cloud, while the second maxima occurred near the time of a deadly pyroclastic density current (PDC) and thunderstorm. Ninety-one percent of the lightning during the event was observed by only one of the lightning sensors, thus showing the importance of combining lightning datasets across multiple frequencies to characterize electrical activity in volcanic eruptions. GLM flashes during the event had a median total optical energy and flash length of 16 fJ, and 12 km, respectively. These median GLM flash energies and lengths observed in the volcanic plume are on the lower end of the flash spectrum because flashes observed in surrounding thunderstorms on 3 June had larger median total optical energy values (130 fJ) and longer median flash lengths (20 km). All 18 cloud-to-ground flashes were negative polarity, supportive of net negative charge within the plume. Mechanisms for the generation of the secondary lightning maxima are discussed based on the presence and potential interaction between ash plume, thunderstorm, and PDC transport during this secondary period of observed lightning.

Download Full-text

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073647 ◽

1973 ◽

Vol 31 ◽

pp. 640-641

Author(s):

P. Hernández-Jáuregui ◽

A. Sosa ◽

A. González Angulo

Keyword(s):

Negative Charge ◽

Iron Hydroxide ◽

Human Spermatozoa ◽

Surface Coat ◽

Cell Surfaces ◽

Colloidal Iron ◽

Cytochemical Study ◽

Specific Permeability ◽

Extracellular Glycoprotein ◽

Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

Download Full-text

The Action of Thrombin on Modified Fibrinogen

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657364 ◽

1983 ◽

Vol 49 (03) ◽

pp. 208-213

Author(s):

A J Osbahr

Keyword(s):

Physical Properties ◽

Negative Charge ◽

Lysine Residue ◽

Fibrinopeptide A ◽

Amino Groups ◽

Lysine Residues ◽

Citraconic Anhydride

SummaryThe modification of canine fibrinogen with citraconic anhydride modified the ε-amino groups of the fibrinogen and at the same time generated additional negative charges into the protein. The addition of thrombin to the modified fibrinogen did not induce polymerization; however, the fibrinopeptide was released at a faster rate than from the unmodified fibrinogen. The physical properties of the citraconylated fibrinogen were markedly altered by the modification of 50-60 lysine residues in one hour. A modified fibrinopeptide-A was released by thrombin from the modified fibrinogen and was electrophoretically more anionic than the unmodified fibrinopeptide-A. Edman analysis confirmed the modification of the lysine residue present in the peptide. The rate of removal of citraconylated fibrinopeptide-A from modified fibrinogen by thrombin was 30 to 40 percent greater than the cleavage of unmodified fibrinopeptide-A from unmodified fibrinogen. However, the modification of 60 or more lysine residues in the fibrinogen produced a decrease in the rate of cleavage of citraconylated fibrinopeptide-A. The results suggest that additional negative charge in the vicinity of the attachment of fibrinopeptide-A to canine fibrinogen aids in the removal of the peptide by thrombin.

Download Full-text

Electron beam induced effects in Cu/GeSe2amorphous films

MRS Proceedings ◽

10.1557/proc-777-t4.7 ◽

2003 ◽

Vol 777 ◽

Author(s):

J.S. Romero ◽

A.G. Fitzgerald

Keyword(s):

Thin Films ◽

Electron Beam ◽

Simple Model ◽

Copper Concentration ◽

Negative Charge ◽

Electron Bombardment ◽

Continuous Operation ◽

Electron Radiation ◽

Crystalline Product ◽

Intense Electron

AbstractCopper migration is observed in the SEM in amorphous GeSe2/Cu thin films when an electron beam is focused in pulsed or continuous operation on the surface of these thin films. The phenomenon can be explained using a simple model in which the population of D- centers is considered to increase upon electron irradiation. The increase in the D- center population is envisaged as due to the breaking of bonds by the electron radiation and by the constant presence of negative charge in irradiated regions. Changes in copper concentration of 20%-30% have been obtained. Additionally we have observed the local crystallization of amorphous GeSe2/Cu thin films in the TEM when the samples were subjected to intense electron bombardment. The crystalline product has been identified as Berzelianite (Cu2Se).

Download Full-text

Investigation of Zero Crossing Detection for First Return Stroke in Negative Cloud-to-Ground Lightning Flash

International Journal of Integrated Engineering ◽

10.30880/ijie.2019.11.03.031 ◽

2019 ◽

Vol 11 (3) ◽

Author(s):

Ahmad Idil Abd Rahman ◽

◽

Muhammad Akmal Bahari ◽

Zikri Abadi Baharudin ◽

◽

...

Keyword(s):

Lightning Flash ◽

Return Stroke ◽

Zero Crossing ◽

Cloud To Ground Lightning

Download Full-text

Interaction of 4-hydroxynonenal-modified low-density lipoproteins with the fibroblast apolipoprotein B/E receptor

Biochemical Journal ◽

10.1042/bj2340245 ◽

1986 ◽

Vol 234 (1) ◽

pp. 245-248 ◽

Cited By ~ 31

Author(s):

W Jessup ◽

G Jurgens ◽

J Lang ◽

H Esterbauer ◽

R T Dean

Keyword(s):

Apolipoprotein B ◽

Negative Charge ◽

Low Density Lipoprotein ◽

Ldl Receptor ◽

Density Lipoprotein ◽

Low Density ◽

Lipid Peroxidation Product ◽

Modified Low Density Lipoproteins ◽

Peroxidation Product

The incorporation of the lipid peroxidation product 4-hydroxynonenal into low-density lipoprotein (LDL) increases the negative charge of the particle, and decreases its affinity for the fibroblast LDL receptor. It is suggested that this modification may occur in vivo, and might promote atherogenesis.

Download Full-text

Critical Technical Issues in High Voltage SiC Power Devices

Materials Science Forum ◽

10.4028/www.scientific.net/msf.600-603.895 ◽

2008 ◽

Vol 600-603 ◽

pp. 895-900 ◽

Cited By ~ 14

Author(s):

Anant K. Agarwal ◽

Albert A. Burk ◽

Robert Callanan ◽

Craig Capell ◽

Mrinal K. Das ◽

...

Keyword(s):

Threshold Voltage ◽

Carrier Mobility ◽

Negative Charge ◽

State Of The Art ◽

Power Devices ◽

Power Mosfets ◽

Large Numbers ◽

Technical Issues ◽

The Difference ◽

Difficult Issue

In this paper, we review the state of the art of SiC switches and the technical issues which remain. Specifically, we will review the progress and remaining challenges associated with SiC power MOSFETs and BJTs. The most difficult issue when fabricating MOSFETs has been an excessive variation in threshold voltage from batch to batch. This difficulty arises due to the fact that the threshold voltage is determined by the difference between two large numbers, namely, a large fixed oxide charge and a large negative charge in the interface traps. There may also be some significant charge captured in the bulk traps in SiC and SiO2. The effect of recombination-induced stacking faults (SFs) on majority carrier mobility has been confirmed with 10 kV Merged PN Schottky (MPS) diodes and MOSFETs. The same SFs have been found to be responsible for degradation of BJTs.

Download Full-text

HPF1 remodels the active site of PARP1 to enable the serine ADP-ribosylation of histones

Nature Communications ◽

10.1038/s41467-021-21302-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Fa-Hui Sun ◽

Peng Zhao ◽

Nan Zhang ◽

Lu-Lu Kong ◽

Catherine C. L. Wong ◽

...

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Active Site ◽

Negative Charge ◽

Structural Data ◽

Dna Breaks ◽

Adp Ribosylation ◽

Local Conformation ◽

Key Residues ◽

Structural Insights

AbstractUpon binding to DNA breaks, poly(ADP-ribose) polymerase 1 (PARP1) ADP-ribosylates itself and other factors to initiate DNA repair. Serine is the major residue for ADP-ribosylation upon DNA damage, which strictly depends on HPF1. Here, we report the crystal structures of human HPF1/PARP1-CAT ΔHD complex at 1.98 Å resolution, and mouse and human HPF1 at 1.71 Å and 1.57 Å resolution, respectively. Our structures and mutagenesis data confirm that the structural insights obtained in a recent HPF1/PARP2 study by Suskiewicz et al. apply to PARP1. Moreover, we quantitatively characterize the key residues necessary for HPF1/PARP1 binding. Our data show that through salt-bridging to Glu284/Asp286, Arg239 positions Glu284 to catalyze serine ADP-ribosylation, maintains the local conformation of HPF1 to limit PARP1 automodification, and facilitates HPF1/PARP1 binding by neutralizing the negative charge of Glu284. These findings, along with the high-resolution structural data, may facilitate drug discovery targeting PARP1.

Download Full-text