23 research outputs found
Ionization Study of Isomeric Molecules in Strong-field Laser Pulses
Citation: Zigo, S., Le, A. T., Timilsina, P., & Trallero-Herrero, C. A. (2017). Ionization Study of Isomeric Molecules in Strong-field Laser Pulses. Scientific Reports, 7, 8. doi:10.1038/srep42149Through the use of the technique of time-of-flight mass spectroscopy, we obtain strong-field ionization yields for randomly oriented 1,2-dichloroethylene (1,2-DCE) (C2H2Cl2) and 2-butene (C4H8). We are interested in studying the effect of conformal structure in strong-field ionization and, in particular, the role of molecular polarity. That is, we can perform strong-field ionization studies in polar vs non-polar molecules that have the same chemical composition. We report our findings through the ionization yields and the ratio (trans/cis) of each stereoisomer pair as a function of intensity
Geminid meteor shower of 1996-2007: Global activity from forward-scatter observations
Activity and mass distribution of the Geminid meteor shower of 1996-2007 from observations by a forward-scatter radio system operating along Bologna-Modra baseline are analyzed and discussed. Global activity curve for overdense echoes of durations ≥ 1 s and ≥ 8 s depicts two distinct peaks at solar longitudes 261.7◦, 262.3◦ and 261.9◦, 262.3◦, respectively. Larger particles are concentrated more to the centre of the stream and slightly shifted towards the descending branch of the stream activity. The mean mass exponent of the Geminids is 1.73
The Lyrid meteor stream: Activity and mass distribution
Observations of the Lyrid meteor shower in 1997-2005 by a forwardscatter radio system for meteor observation operating simultaneously along two baselines, Bologna-Lecce (Italy) and Bologna-Modra (Slovakia), are analysed and
discussed. The activity curves of long-duration echoes (≥ 8 s) and their variations indicate a complex structure of the stream. The Earth crosses the stream at a half maximum rate level in about two days. The overall activity peak derived from all observed returns is at solar longitude 32.30o (eq. 2000.0). The mass distribution exponent s and its variations in the period of the shower maximum indicate a relatively stable population of meteoroids in the stream exhibiting filamentary structure
The daytime Taurid complex meteor streams: Activity and mass distribution
The activity and mass distribution of the summer daytime Taurid meteor complex streams Zeta Perseids and Beta Taurids in 1997-2004 is analysed and discussed. The results are based on radio observations obtained by the BLM
forward-scatter system (Italy-Slovakia) and by the Ondrejov backscatter meteor radar (Czech Republic). The observed positions of maxima of the streams are in a general agreement with previous analysis. The observations indicate a filamentary structure of the streams, the existence of which is supported also by the mass exponent values
The Quadrantid meteor shower 1997-2004: Activity and mass distribution
Observations of the Quadrantid meteor shower in 1997-2004 by the BLM forward-scatter radio system for meteor observation carried out along two baselines, Bologna-Lecce (Italy) and Bologna-Modra (Slovakia), are analysed from
the viewpoint of activity and mass distribution and results are discussed. The activity curves of long-duration echoes (≥8 s) and their variations indicate a filamentary
structure of the stream. The width of the stream at a
half-maximum rate level is less than half a day (5–11.5 h). The mass distribution exponent s in the period of the shower maximum shows significant changes in individual years, with a high contribution of larger particles in 1997 and small particles in 2001, 2003 and 2004
The Geminid meteor shower of 1996-2003 from forward-scatter observations: Activity and mass distribution
Observations of the Geminid meteor shower in 1996-2003 by a
forward-scatter radio system for meteor observation operating simultaneously along two baselines, Bologna-Lecce (Italy) and Bologna-Modra (Slovakia), are analysed and discussed. The activity curves of long-duration echoes (≥ 8 s) and their variations indicate a complex structure of the stream. The width of the stream at a half maximum rate level is about two days. The mass distribution exponent s and its variations in the period of the shower maximum indicate a relatively stable population of meteoroids in the stream with a population of smaller particles preceding
the activity peak composed of larger particles
Pharmacologic treatment with CPI-613 and PS48 decreases mitochondrial membrane potential and increases quantity of autolysosomes in porcine fibroblasts
A metabolic phenomenon known as the Warburg effect has been characterized in certain cancerous cells, embryonic stem cells, and other rapidly proliferative cell types. Previously, our attempts to induce a Warburg-like state pharmaceutically via CPI-613 and PS48 treatment did augment metabolite production and gene expression; however, this treatment demonstrated a Reverse Warburg effect phenotype observed in cancer-associated stroma. In the current study, we inquired whether the mitochondria were affected by the aforementioned pharmaceutical treatment as observed in cancerous stromal fibroblasts. While the pharmaceutical agents decreased mitochondrial membrane potential in porcine fetal fibroblasts, the number and size of mitochondria were similar, as was the overall cell size. Moreover, the fibroblasts that were treated with CPI-613 and PS48 for a week had increased numbers of large autolysosome vesicles. This coincided with increased intensity of LysoTracker staining in treated cells as observed by flow cytometry. Treated fibroblasts thus may utilize changes in metabolism and autophagy to mitigate the damage of treatment with pharmaceutical agents. These findings shed light on how these pharmaceutical agents interact and how treated cells augment metabolism to sustain viability. c2019, The Author(s).Includes bibliographical references
A Non-synonymous point mutation in a WD-40 domain repeat of EML5 leads to decreased bovine sperm quality and fertility.
This study is part of a concerted effort to identify and phenotype rare, deleterious mutations that adversely affect sperm quality, or convey high developmental and fertility potential to embryos and ensuing progeny. A rare, homozygous mutation in EML5 (EML5R1654W), which encodes a microtubule-associated protein with high expression in testis and brain was identified in an Angus bull used extensively in artificial insemination (AI) for its outstanding progeny production traits. The bull?s fertility was low in cross-breeding timed AI (TAI) (Pregnancy/TAI = 25.2%; n = 222) and, in general, AI breeding to Nellore cows (41%; n = 822). A search of the 1,000 Bull Genomes Run9 database revealed an additional 74 heterozygous animals and 8 homozygous animals harboring this exact mutation across several different breeds (0.7% frequency within the 6,191 sequenced animals). Phenotypically, spermatozoa from the homozygous Angus bull displayed prominent piriform and tapered heads, and outwardly protruding knobbed acrosomes. Additionally, an increased retention of EML5 was also observed in the sperm head of both homozygous and heterozygous Angus bulls compared to wild-type animals. This non-synonymous point mutation is located within a WD40 signaling domain repeat of EML5 and is predicted to be detrimental to overall protein function by genomic single nucleotide polymorphism (SNP) analysis and protein modeling. Future work will examine how this rare mutation affects field AI fertility and will characterize the role of EML5 in spermatogenesis
Attitude determination of cylindrical rocket bodies by using simultaneous bistatic photometric measurements.
The rocket bodies, as a part of the space debris population, poses a significant threat and are one of the prime targets for active debris removal (ADR) missions due to their large size and orbital regimes. Accurate monitoring of their dynamic properties like rotation period and tumbling axis is crucial for predicting their orientation and assisting potential applicable ADR missions.
We determine the tumbling axis direction using the low-resolution Williams model [1] based on our own photometric measurements. This model is ideal for cylindrical objects, assuming rotation around an axis perpendicular to the central axis in body-fixed reference frame. From the brightness ratio, which represents the difference between maximum and minimum brightness values during one rotation, it can estimated the possible tumbling axis orientation. The brightness ratio depends on the object’s position, tumbling axis orientation, and observer’s location. Typically, when both the observer’s location and object’s position are known, we can derive the brightness ratio from the series photometric measurements.
This method requires at least two observations from different perspectives over a relatively short period, as large changes in the tumbling axis are not expected by the model. Collecting data simultaneously from two different locations helps meet these challenges in the most effective way.
We present tumbling axis estimations for CZ-3B, H-2A and FALCON 9 rocket bodies, selected as calibration test objects. They are expected to rotate about an axis perpendicular to their central axis due to their moments of inertia. These objects mainly reflect light from their mantle, aligning well with the Williams model [1]. Our results are based on photometric measurements from two telescopes, AGO70 located in Slovakia and ZIMLAT located in Switzerland, focusing on CZ-3B, H-2A and FALCON 9 upper stages with eccentric orbits and low perigee distances, simulating near-future re-entries and close-range observations of LEO objects. This approach aims to establish a methodology applicable to LEO objects, as potential targets for future ADR missions