Association between DNA ploidy and micronucleus frequency in chronic smokers and impact of smoking cessation.

Tobacco use may initiate the process of oral carcinogenesis with clinically undetectable changes. Smoking cessation may prevent its progression. The objective of this study was to evaluate the association between DNA ploidy and micronucleus (MN) frequency in chronic smokers. Three groups were evaluated: Smoker Group, Former Smoker Group and Control Group. Exfoliative cytology was performed on the lateral border of the tongue and mouth floor. MN and DNA ploidy analyses were performed, as well as the correlation between the variables. The data showed a difference between the groups for the total MN (p = 0.0227), and the Smoker group had the highest mean (4.22 ± 4.12). The three groups did not differ statistically from each other on ploidy evaluation (p-value > 0.05). There was also an association between aneuploidy and increased MN frequency in the Former Smoker group (p = 0.0036). In conclusion, these results point out that there is a relationship between the frequency of MN and aneuploidy in former smokers. Moreover, smoking cessation, even for a short period of time, may promote the decrease of MN frequency caused by tobacco use.

Potential Pitfalls in the Analysis and Structural Interpretation of Seismic Data from the Mars InSight Mission.

The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.

DNA nucleotide sequence analysis of the PvuII DNA fragment L of the genome of insect iridescent virus type 6 reveals a complex cluster of multiple tandem, overlapping, and interdigitated repetitive DNA elements.

The DNA nucleotide sequence of the PvuII DNA fragment L (0.920 to 0.944 map units (m.u.)) of the genome (209 kbp) of insect iridescent virus type 6 was determined. The size of this DNA fragment was 5064 by with a base composition of 39.79% G + C and 60.21 % A + T. The DNA sequence contained many perfect direct repeats of sizes up to 145 bp. In addition to these repetitions, a cluster of four imperfect repetitive DNA elements (R1 to R4) with a complex structural arrangement was detected. R1, R2, and R3 existed in duplicate (two boxes (B)) between nucleotide positions 271 and 3466) and their size were as follows: R1-B1/B2 (567/568 bp), R2-B1/B2 (917/931 bp), and R3-B1/B2 (92/88 bp). The R4 repetitive element was found in 12 boxes (between bases 1301 and 4417), which were interrupted at nucleotide positions 1883 to 2236 and 3341 to 3587. These interruptions define three segments (S) harboring boxes B1 to B3 (S1), B4 to B8 (S2), and B9 to B12 (S3). The size of the individual boxes was found to be 239, 233, 107, 244, 222, 242, 242, 148, 240, 242, 242, and 102 by for R4-B1 to B12, respectively. Five open reading frames (ORFs of 118 to 333 amino acid (AA) residues) were detected. The analysis of the amino acid sequences of the largest ORF revealed that the deduced amino acid sequence of the putative gene product contained two repetitions TR1 (three domains of 50 AA) and TR2 (two domains of 74 AA). Sequences of 43 amino acid residues of ORF 5 (160 to 202 AA) were homologous within the majority of ORFs. A consensus sequence-MAN L(X)6 IGSSST(X)6 L(X)1 LGS(X)1 LQISG(X)2 L(X)1 VN-was found in all five ORFs. Although classical canonical and noncanonical transcriptional start signals were detectable, polyadenylation signals were not observed.