Low Levels Of Damage Research Articles

THE USE OF AERODYNAMIC PROPERTIES OF SEEDS TO OPERATE A UNIVERSAL SYSTEM OF SEEDING PNEUMATIC UNIT VACUUM ACTION

The device of the pneumatic sowing device of vacuum action which differs in simplicity of a design, the lowered material consumption, low level of mechanical damage of a sowing material (minimum values of percent of crushing of seeds), possibility of simultaneous sowing of seeds of two different cultures in one row (it is important for fodder crops) is developed. Structurally, the following basic changes have been made in the pneumatic sowing device:1. The scattering part of the pipe (with experimentally selected parameters, length 100 ... 120 mm and a sieving angle 80 ... 90°) allows the main zone to intercept the flow of seeds from the hopper, without passing them to the lower part of the sowing disc – in the accumulation zone; 2. The air flow from the nozzle supports the seeds (through the use of their useful aerodynamic qualities) in a suspended state near the holes of the sowing disc, which contributes to the reliable suction of the seeds to the holes of the disc. At the same time, the nozzles prevent the penetration of seeds into the accumulation zone, which allows to improve the quality of the sowing apparatus. The exclusion of the tedder from the structural part of the sowing device reduces the percentage of mechanical damage to the seeds (which affects the yield), as well as the material capacity of the structure itself.

Multibiomarker interactions to diagnose and follow-up chronic exposure of a marine crustacean to Hazardous and Noxious Substances (HNS)

Integrated compensatory responses of physiological systems towards homeostasis are generally overlooked when it comes to analysing alterations in biochemical parameters indicative of such processes. Here an hypothesis-driven multivariate analysis accounting for interactive multibiomarker responses was used to investigate effects of long-term exposure of Carcinus maenas to Hazardous and Noxious Substances (HNS). Adult male crabs were exposed to low and high post-spill levels of acrylonitrile (ACN) or aniline (ANL) for 21d. Bioaccumulation, feeding behaviour, and biomarkers related to mode-of-action (MoA) (detoxification, neurotransmission and energy production) were evaluated over time. Distinct temporal patterns of response to low and high exposure concentrations were depicted, with a main set of interactive multibiomarker predictors identified for each HNS (five for ACN and three for ANL), useful to follow coupled evolvement of biomarker responses. ACN caused peripheral neurotoxic effects coupled with enhanced biotransformation and significant oxidative damage particularly relevant in gills. ANL elicited alterations in central neurotransmission affecting ventilation coupled with very low levels of oxidative damage in gills. Results indicate chronic toxicity data are determinant to improve HNS hazard assessment if the aim is to obtain reliable risk calculations, and develop effective predictive models avoiding overestimation but sufficiently protective. Accounting for multibiomarker interactions brought otherwise overlooked information about C. maenas responses and MoA of ACN and ANL.

Quantitative 3D Trajectory Measurement for Percutaneous Endoscopic Lumbar Discectomy

Percutaneous endoscopic lumbar discectomy (PELD) has become an increasingly popular minimally invasive spinal surgery. Due to the technical evolution of PELD, the focus of decompression has shifted from the central nucleus to the subannular-protruded disc herniation, which allows direct neural decompression. Surgical entry into the spinal canal leads to the greater possibility of bony structure obstruction, thus the location and direction of the working channel are crucial. The existing preoperative measuring methods mainly rely on 2-dimensional (2D) x-ray images or MRI cross-sections. Because the bony structure and the trajectory are 3-dimensional (3D), the relationship between the anatomical lumbar structure and the working channel cannot be precisely evaluated. To investigate a 3D method and quantitatively evaluate the trajectory for percutaneous endoscopic lumbar discectomy (PELD). Technical note. Pain medicine center of a university hospital. Twenty patients suffering from L4/5 disc herniation were enrolled in this study. After reconstructing the preoperative CT images, the virtual trajectory was placed into the intervertebral foramen through gradient-changing angulations in relation to the coronal and transverse planes. The overlapping portion of the virtual trajectory and the lumbar vertebrae was evaluated. In addition, the probability of atypical structure involvement was calculated. As cephalad angulation (CA) increased, the intersection volume of the L4 inferior articular process increased, while the total intersection volume, the intersection volume of the L5 superior articular process, the intersection volume of the facet joint, and the volume proportion of L5 superior articular process intersection in the facet joint all decreased. As coronal plane angulation (CPA) increased, the total intersection volume, the intersection volume of the L4 inferior articular process, and the intersection volume of the facet joint all increased, while the volume proportion of the L5 superior articular process intersection in the facet joint decreased. When CA increased to 15°-20°, there was a high probability of atypical structure involvement, whereas such a probability in the groups of CA 0° (CPA 15°, 20°, and 25°), CA 5° and CA 10° was low. Only patients with L4/5 herniation were evaluated in this study. In terms of the regularity, the ideal angulation for L4/L5 PELD is CPA 5°-10° and CA 5°-10°, which can lead to a relatively low level of total damage to the bony structure, minimal damage to the facet joint, and negligible involvement of atypical structures. Lumbar disc herniation, percutaneous endoscopic lumbar discectomy (PELD), transforaminal, trajectory, 3D method, quantitative measurement, angulation, bony structure obstruction.

Motivations to prepare after the 2013 Cook Strait Earthquake, N.Z.

We investigated responses to the 2013 Cook Strait earthquake sequence, New Zealand. This included two foreshocks (M5.7 and M5.8) and a mainshock doublet pair: M6.5 Cook Strait (CS) earthquake on 21st July and M6.6 Lake Grassmere (LG) earthquake on Friday 16th August. We examined relationships between preparedness, experience and beliefs during the earthquakes, as well as concern and subsequent preparedness actions. Results indicate that earthquake characteristics (e.g., time, location) influence the types of preparedness actions. While there was a reduction in new actions from the first mainshock doublet earthquake (CS) to the second (LG), there were a large number of participants who reviewed or revisited their prior actions, related to their beliefs about impacts, in a form of problem-focused targeted action. Females took more actions than did males, and had a higher rate of immediate aftershock concern. For all participants, concern was greater after the CS earthquake than after the full earthquake sequence, supporting the findings of McClure et al. (2016) that there is a limited window after an event to maximise the opportunity for effective preparedness initiatives. Findings additionally suggest that such post-earthquake preparedness initiatives should consider the impacts that elicited the highest rate of concern in an event, and should tailor messages towards them. While this earthquake sequence resulted in low levels of impact and damage, it presents interesting findings regarding how disruption (in lieu of major damage) influences earthquake preparedness actions, which is particularly important to understand in highly active regions often exposed to smaller impact events.

Recombinant FSH Improves Sperm DNA Damage in Male Infertility: A Phase II Clinical Trial.

Background and objectives: Male infertility is a global health dilemma and Follicle-Stimulating Hormone (FSH) administration has shown promising results. Several studies showed that infertile men with normal semen parameters have low levels of DNA damage while infertile men with abnormal semen parameters have more damage at the DNA level. Sperm DNA damage may affect the reproductive outcome and has been associated with failure in the achievement of competent embryos and pregnancy fulfillment. The aim of this study was to evaluate whether the administration of recombinant FSH (Gonal-f® PEN 900 IU) could improve sperm DNA fragmentation in men with infertility. The secondary endpoints of this study were to evaluate the FSH effects on sperm parameters and hormonal assets.Methods: A longitudinal, prospective, multicenter, open-label clinical trial was carried out. Infertile couples were recruited from six Italian Reproductive Medical Centers and 115 infertile men were enrolled for this study. All participants were treated with subcutaneous injections of Gonal-f® 150 IU every other day, within a 3 month-time frame. The semen samples were examined in accordance to the 2010 World Health Organization criteria. Sperm DNA Fragmentation (DFI) was determined by fluorescence microscopy using terminal deoxynucleotidyl transferase-mediated d-UTP Nick-end Labeling (TUNEL) assay. Statistical analysis was performed using both the t-test for paired samples and the Wilcoxon signed-rank test.Results: FSH administration improved DFI in 67% of patients, with an average decrease of 35.4% compared to the baseline. This improvement is more evident in men with basal DFI lower than 17% and in those with FSH basal levels between 2.16 and 4.27 IU/L. In addition, FSH enhanced the gonadal function, increasing the hormones AMH and Inhibin B and semen parameters. Limitation of these results are represented by the absence of a placebo group and of FSHR genotype stratification sub-analysis.Conclusion: Recombinant FSH 150 IU is well tolerated and effective in eliciting a significant DFI reduction as well as in improving gonadal function.Trial Registration: EUDRACT Number 2010-020196-23. Registred 14 April 2011.

Abstract SY22-02: Metabolic vulnerability of PTEN mutant cancer

Abstract Signaling pathways that act as drivers of cancer cell growth and proliferation activate metabolic pathways required to generate the building blocks required for cell doubling. Loss of PTEN activates PI3K, AKT and mTOR to stimulate glucose and glutamine flux to allow DNA replication. One of the metabolic pathways that is activated after deletion of both alleles of PTEN is the de novo pyrimidine synthesis pathway. PTEN null cells show evidence of increased DNA replication and low levels of damage at replication forks that can be rescued by providing supplementary uridine. Interruption of de novo pyrimidine synthesis with an inhibitor of dihydroorotate dehydrogenase (DHODH) increased DNA damage at replication forks of PTEN null cells that ultimately led to chromosome breaks detected in mitosis and cell death. This cellular vulnerability to inhibition of DHODH was rescued with uridine, demonstrating the specificity of the effect. Exploration of the mechanism that led to vulnerability of PTEN null cells demonstrated that it was due to defective ATR signaling at replication forks that was a consequence of activated AKT, which phosphorylate and attenuate TOPBP1 and CHK1. Complementation of PTEN null cells with mutants of TOPBP1 and CHK1 that cannot be phosphorylated by AKT rescued the cells from DNA damage and cell death due to inhibition of DHODH. Tumor cell lines lacking PTEN tended to be more sensitive to DHODH inhibition than PTEN wild type cells were. In conclusion, the attenuated ATR signaling and increased flux of nucleotides to newly synthesized DNA at replication forks makes PTEN mutant cells vulnerable to disruption of de novo pyrimidine synthesis. Citation Format: Ramon E. Parsons. Metabolic vulnerability of PTEN mutant cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr SY22-02.

PO-129 In vitro radiosensitivity and repair kinetics of PBMCs from prostate cancer patients and healthy donors evaluated by comet assay

IntroductionA high cellular radiosensitivity is connected with a risk for development of severe side effects after radiotherapy. In this study we have attempted to find a correlation between the initial radiosensitivity of in vitro irradiated peripheral blood mononuclear cells (PBMC) of prostate cancer patients and the adverse side effects of radiotherapy.Material and methodsPBMCs isolated from 7 prostate cancer patients, before the onset of radiotherapy and 3 healthy men were exposed in vitro to 2 Gy of x-ray radiation (Varian, 6 MeV). Following irradiation cell death was measured using the Annexin V/PI assay. DNA repair kinetics (0 and 24 hour after irradiation) was performed using the comet assay, and the results were expressed as% of tail DNA. Acute toxicity were graded according to the EORTC radiation morbidity scoring scale.Results and discussionsOur data show that the in vitro irradiation of PBMCs in prostate cancer patients initially caused a significantly higher DNA damage than in the control group of healthy donors. After a repair time of 24 hour, samples from all healthy donors showed no residual DNA damage (average 2.6%) in PBMCs. If all patients are observed for 0 hour and 24 hour after in vitro PBMCs irradiation then there is a significant reduction in the degree of DNA damage, from 35.5 to 30.4 tail% DNA. What is also important is that 4 patients had a very low level of DNA damage, which can be considered as normal cellular reaction to irradiation, while 3 patients had a very high level of damage. Also, in 5 out of 7 examined prostate cancer patients, there was an increase in the percentage of PBMCs in the early and late stages of apoptosis 24 hour after in vitro irradiation of their PBMCs. Most patients had mild side reactions to radiotherapy and were graded as grade 1 (per EORTC scale). Only in 1 of 7 patients observed side effects are classified as grade 2 and this is in correlation with a very high level of DNA damage (82.25% initial, versus 64.77% 24 hour after in vitro irradiation).ConclusionOur study was insufficient to reveal the relationship between the risk of developing side effects to radiotherapy and the sensitivity of PBMCs irradiated in vitro, measured by comet assay. A larger number of patients and further studies are necessary to confirm the potential application of the comet assay.

The influence of helium on cavity evolution in ion-irradiated T91

The effect of helium pre-implanted in concentrations spanning 0 to 1000 appm on the swelling evolution in ferritic-martensitic alloy T91 was explored. Irradiation with 5.0 and 4.4 MeV Fe2+ ions at 460 °C up to damage levels of 350 dpa were performed with pre-implanted helium levels of 0, 1, 10 and 1000 appm. Low concentrations of helium were found to enhance nucleation at low damage levels. However, at high damage levels, differences in nucleation became insignificant, and nearly identical cavity distributions were created. At low helium levels, the cavity evolution was facilitated by similar cavity sink strengths. High helium concentrations reduced the critical cavity radius and resulted in the formation of a high-density bubble population. The bubbles were <4 nm and remained stable even up to high damage levels, while the growth of larger cavities was suppressed. The suppression of swelling was found to be a result of helium trapping or alteration of cavity and dislocation bias. Dislocation and precipitate evolution was also studied and exhibited relative insensitivity to helium concentration, and did not significantly influence the cavity evolution.

Designing Thinning Operations in 2nd Age Class Pine Stands—Economic and Environmental Implications

The application of a harvester for thinning operations in young stands can pose several dilemmas. Firstly, the value of the timber obtained should be higher than the cost of the thinning operation—this is especially difficult with young stands, where the timber is of a small size and productivity is low. In addition, small harvesters used for thinning usually have short cranes, less than 10 m in length, which is rather impractical in stands where the distance between strip roads is a standard 20 m. The aim of this research was to select the best mechanised thinning operation, taking into account economic suitability and some environmental aspects (damage to the remaining stand and density of strip roads). The research was carried out in a 31-year-old pine stand (11.27 ha) in which three different harvester thinning (T) operations were designed: TM1) with midfield and one harvester pass, TM2) with midfield and two harvester passes and TWM) without midfield and one harvester pass. In all the proposed operations, a Vimek 404 T5 harvester (with a 4.6 m-long crane) and a Vimek 606 TT forwarder were used. The most economic operation was TWM, with a total cost of €13.73 m−3, while TM1 was 13% more expensive at €15.51 m−3. The lowest level of damage, 1.5%, was recorded in TWM, while in TM1 the level was 2.1%. The TWM operation required a net of strip roads twice as dense as in TM1. Taking into account all the analysed aspects, a thinning operation with midfield and one harvester pass is recommended when using the Vimek 404 T5 harvester and the Vimek 606 TT forwarder in the first thinning of a pine stand.

Study the HVAC system photodegradation caused by the low level UVC light irradiance used for coil maintenance and air stream disinfection

This paper studied the detrimental effects of low (50–750 µW/cm2) level ultraviolet C (UVC) irradiation used for coil maintenance and air stream disinfection on the surfaces of different HVAC materials and components. Photoreactors were initially used to study low level UVC photodegradation of materials with the highest UVC susceptibilities and demonstrated that the rates/mechanisms of surface damage are highly dependent on the material processing history as well as polymer structure. Due to the low levels of damage after months of exposure (UVC damage equal in magnitude to surface roughness of polished surfaces), the low level UVC photoreactor results described herein were unable to establish a mathematical relationship between UVC irradiation level and photodegradation rate, especially for the less susceptible materials. However, the results did indicate that the UVC susceptibility rankings were unaffected by UVC irradiation levels, which indicated that high UVC irradiation levels are suitable for shortening the test times required to obtain sufficient surface photodegradation to rank the UVC susceptibilities of polymers/materials used in HVAC systems. To make the UVC susceptibility testing suitable for nonlaboratory settings, a test cell fixture designed to house a single sample, a variable power UVC LED, and an optical photodegradation measuring device was constructed and evaluated. The ability to run each test cell at a different UVC level by simply adjusting the LED input power level allowed multiple samples to be run simultaneously under a wide range of UVC levels/environmental conditions.

Susceptibility of eucalyptus species and hybrids to the gall wasp Leptocybe invasa (Hymenoptera: Eulophidae) in northern Misiones, Argentina

Aim of study: To analyze the susceptibility of Eucalyptus and hybrids species to Leptocybe invasa through field assays.Area of study: The north of the Argentine province of Misiones (Colonia Delicia). Material and methods: A total of 11 Eucalyptus species and 2 hybrids were surveyed for damage and severity of L. invasa infestation. Six evaluations were made during an annual period.Main results: The susceptibility ranking to L. invasa from highest to lowest was E. tereticornis &gt; E. propinqua &gt; E. dunni &gt; E. camaldulensis &gt; E. grandis &gt; E. major &gt; E. longistrata &gt;E. grandis × E. camaldulensis. However, E. moluccana, E. urophylla × E. grandis and E. urophylla were tolerant to L. invasa.Research highlights: This study suggests that in Misiones, E. tereticornis is the most sensible eucalyptus species to gall wasp attack, whereas other species and hybrids presented low damage levels or tolerance to L. invasa region.

Resolving the phylogenetic position of Darwin's extinct ground sloth (Mylodon darwinii) using mitogenomic and nuclear exon data.

Mylodon darwinii is the extinct giant ground sloth named after Charles Darwin, who first collected its remains in South America. We have successfully obtained a high-quality mitochondrial genome at 99-fold coverage using an Illumina shotgun sequencing of a 12 880-year-old bone fragment from Mylodon Cave in Chile. Low level of DNA damage showed that this sample was exceptionally well preserved for an ancient subfossil, probably the result of the dry and cold conditions prevailing within the cave. Accordingly, taxonomic assessment of our shotgun metagenomic data showed a very high percentage of endogenous DNA with 22% of the assembled metagenomic contigs assigned to Xenarthra. Additionally, we enriched over 15 kb of sequence data from seven nuclear exons, using target sequence capture designed against a wide xenarthran dataset. Phylogenetic and dating analyses of the mitogenomic dataset including all extant species of xenarthrans and the assembled nuclear supermatrix unambiguously place Mylodon darwinii as the sister-group of modern two-fingered sloths, from which it diverged around 22 million years ago. These congruent results from both the mitochondrial and nuclear data support the diphyly of the two modern sloth lineages, implying the convergent evolution of their unique suspensory behaviour as an adaption to arboreality. Our results offer promising perspectives for whole-genome sequencing of this emblematic extinct taxon.

A Novel G-Protein-Coupled Receptors Gene from Upland Cotton Enhances Salt Stress Tolerance in Transgenic Arabidopsis.

Plants have developed a number of survival strategies which are significant for enhancing their adaptation to various biotic and abiotic stress factors. At the transcriptome level, G-protein-coupled receptors (GPCRs) are of great significance, enabling the plants to detect a wide range of endogenous and exogenous signals which are employed by the plants in regulating various responses in development and adaptation. In this research work, we carried out genome-wide analysis of target of Myb1 (TOM1), a member of the GPCR gene family. The functional role of TOM1 in salt stress tolerance was studied using a transgenic Arabidopsis plants over-expressing the gene. By the use of the functional domain PF06454, we obtained 16 TOM genes members in Gossypium hirsutum, 9 in Gossypium arboreum, and 11 in Gossypium raimondii. The genes had varying physiochemical properties, and it is significant to note that all the grand average of hydropathy (GRAVY) values were less than one, indicating that all are hydrophobic in nature. In all the genes analysed here, both the exonic and intronic regions were found. The expression level of Gh_A07G0747 (GhTOM) was significantly high in the transgenic lines as compared to the wild type; a similar trend in expression was observed in all the salt-related genes tested in this study. The study in epidermal cells confirmed the localization of the protein coded by the gene TOM1 in the plasma membrane. Analysis of anti-oxidant enzymes showed higher concentrations of antioxidants in transgenic lines and relatively lower levels of oxidant substances such as H2O2. The low malondialdehyde (MDA) level in transgenic lines indicated that the transgenic lines had relatively low level of oxidative damage compared to the wild types. The results obtained indicate that Gh_A07G0747 (GhTOM) can be a putative target gene for enhancing salt stress tolerance in plants and could be exploited in the future for the development of salt stress-tolerant cotton cultivars.

Protective role of nimbolide against chemotherapeutic drug hydroxyurea induced genetic and oxidative damage in an animal model

Nimbolide is known to be an antioxidant found in neem plant. Hydroxyurea is a medication frequently used in sickle-cell disease, different cancers and HIV infection. The present study aimed to evaluate the adverse effect of HU and possible amelioration by nimbolide in Wistar rats. To test our hypothesis, we performed genotoxicity tests, biochemical assays, and histopathological studies. We observed that HU caused higher levels of genotoxicity in the treated animals. The observed genetic and oxidative damage might be due to the presence of reactive species as HU increased the level of the malondialdehyde-a biomarker of oxidative damage. Interestingly, co-treatment of animals with HU and nimbolide showed a lower level of damage. We conclude that nimbolide significantly protects the cells from the adverse effect of HU and could be considered as a potential adjuvant for the patients under HU therapy.

Morphological defects, sperm DNA integrity, and protamination of bovine spermatozoa.

The association between sperm morphology characteristics and DNA conformation and integrity is still controversial. In bulls, major morphological sperm abnormalities have been associated with reduced fertility, and morphological assessment is used to provide an indication of potential fertility of the individual. Sperm DNA fragmentation and damage has a negative effect on embryo development and subsequently fertility, with bull spermatozoa generally displaying low levels of DNA damage and tight chromatin. However, sensitive methods for detecting chromatin damage may reveal associations with morphological defects. The objective was to determine whether morphological sperm abnormalities and variables expressing sperm DNA integrity and protamination are correlated in bulls, using the sperm chromatin structure assay (SCSA) and the sperm protamine deficiency assay (SPDA). Electroejaculated samples (n=1009) from two-year-old tropically adapted bulls were split and fixed and submitted to microscopic sperm morphology assessment, and snap-frozen for sperm nuclear integrity assessments by SPDA and SCSA. For SPDA, the variables were defective (MCB) and deprotaminated (HCB), and for SCSA, the variables were DNA fragmentation index (DFI) and high DNA stainability (HDS). HCB correlated with DFI; τKen2 =0.317 and HDS; 0.098, and MCB correlated with DFI; 0.183 (p<0.001). The percentage of morphological normal spermatozoa was correlated negatively to DFI; τKen2 =-0.168, MCB; -0.116 and HCB; -0.137 (p<0.001). HCB and DFI were both positively correlated to head defects, proximal droplets, and spermatogenic immaturity, but not to distal droplets, vacuoles, or diadems. Sperm DNA integrity and protamination, using the SCSA and SPDA, respectively, in bulls show associations with morphological parameters, particularly with head shape abnormalities and indicators of spermatogenic immaturity, including proximal droplets. The vacuoles and diadem defects were not correlated with sperm nuclear integrity, and hence, these are likely physiological features that may not directly affect sperm chromatin configuration.

Epidemi Penyakit Busuk Buah yang Disebabkan oleh Phytopthora palmivora Butl. Pada Perkebunan Rakyat di Distrik Kosiwo, Yapen Selatan dan Angakaisera, Kabupaten Yapen

The objective of this research is to know the pod rot disease�s epidemic in Kosiwo, South Yapen and Angkaisera Distric in Yapen regency. The result shown that the disease intensity in Kosiwo, South Yapen, and Angkaisera is ranged between 54.2 percent to 82.4 percent with average 66 percent. The high level of damage is 82.4 percent found in Ariepi village Kosiwo district and the low level of damage is 54.2 percent in Kontiunai village. The high level of disease intensity is influence by the plant�s susceptibility, the virulence of pathogen, compatibility of environment, and disease management of farmer.

Dynamic Characteristics of Green Sandstone Subjected to Repetitive Impact Loading: Phenomena and Mechanisms

A split Hopkinson pressure bar apparatus driven by a pendulum hammer was used to perform uniaxial compression tests to examine the degradation process of green sandstone subjected to repetitive impact loading. The acoustic characteristics, dissipated energy, deformation characteristics, and microstructure evolution were investigated. The representative stress–strain curve can be broken into five stages that were characterized by changes in the axial strain response during impact loading. Both the ultrasonic wave velocity and cumulative dissipated energy exhibited obvious three-stage behavior with respect to the impact number. As the impact number increased, more than one peak was observed in the frequency spectra, and the relative weight of the peak frequency increased in the low-frequency range. According to the evolution of the ultrasonic wave velocity, the degradation process was divided into three stages. By comparing the intact stage I and early stage II microcrack development patterns, the initiation of new cracks and elongation of existing cracks were identified as the main degradation mechanisms. Furthermore, a slight increase in the number of cracks was observed, and microcrack lengths steadily increased. Moreover, due to the low level of microcrack damage, the deformation mechanism was mainly characterized by volume compression during impact loading. In late stage II, the main degradation mechanism was the elongation of existing cracks. Additionally, as microcracks accumulated in the rock samples, cracks were arranged parallel to the loading direction, which led to volume dilation. In stage III, microcracks continued to elongate nearly parallel to the loading direction and then linked to each other, which led to intense degradation in the rock samples. In this stage, rock sample deformation was mainly characterized by volume dilation during impact loading. Finally, rock samples were split into blocks with fractures oriented subparallel to the loading direction. These results can improve the understanding of the stability evaluations of rock structures subjected to repetitive impact loading.

Co-exposure to environmental carcinogens in vivo induces neoplasia-related hallmarks in low-genotoxicity events, even after removal of insult

Addressing the risk of mixed carcinogens in vivo under environmentally-realistic scenarios is still a challenge. Searching for adequate biomarkers of exposure requires understanding molecular pathways and their connection with neoplasia-related benchmark pathologies. Subjecting the zebrafish model to realistic concentrations of two genotoxicants and carcinogens, cadmium and benzo[a]pyrene, isolated and combined, yielded low levels of DNA damage. Altogether, the organisms’ mechanisms of DNA repair, oxidative stress and phases I and II were not overwhelmed after two weeks of treatment. Still, transcriptional responses related to detoxification (epoxide hydrolase and UDP-glucuronosyltransferase) were higher in animals subjected to the combination treatment, inclusively following depuration. Nonetheless, inflammation and formation of hyperplasic foci in fish epithelia were more severe in animals exposed to the combined substances, showing slower recovery during depuration. Additionally, the combination treatment yielded unexpected increased expression of a ras-family oncogene homologue after depuration, with evidence for increased tp53 counter-response in the same period. The findings indicate that oncogene expression, cell proliferation and inflammation, may not require noticeable DNA damage to occur. Furthermore, albeit absent proof for neoplasic growth, the removal of chemical insult may promote tissue recovery but does not entirely clear molecular and histopathological endpoints that are commonly associated to neoplasia.

Poly (vinyl alcohol) supported thermally reduced graphene oxide (TRGO) nanosheets exhibit enhanced electrical and mechanical behavior

In the present work thermally reduced graphene oxide was reinforced into polyvinyl alcohol (PVA) film by the solution cast method. The structural and morphological characterization of prepared nanocomposite materials was done using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Raman spectroscopy, scanning electron microscopy(SEM), field emission gun-transmission electron microscopy (FEG-TEM) and atomic force microscopy (AFM) techniques. The microscopic observations revealed by the SEM and TEM suggested for complete dispersion of thermally reduced graphene oxide (TRGO) into the PVA film. The XRD studies of nanocomposite revealed an enhanced crystallinity in comparison to the native PVA film. The thermal reduction process enabled homogenous dispersion of reduced graphene oxide sheets and improved the electrical conductivity of nanocomposites due to their low damage level of conjugate-structures. As a result, the percolation threshold of PVA-TRGO nanocomposites was ∼0.189 wt% which is lower than the presently reported one (2 to 10 wt%). At the TRGO content of 2 wt%, the electrical conductivity of PVA-TRGO nanocomposite reached from 0.2491 to 0.2631Scm−1. The enhancement mechanism of the composite was explained by the existence of multi-hydrogen bonds between the hydroxyl (-OH) groups of PVA and oxygen-containing functional groups of graphene oxide (GO). The AC electrical conductivity and mechanical studies results indicated that the performance of nanocomposites was significantly improved as compared to the native PVA and offered the possibilities to use the prepared nanocompsoite films to be used in electronic devices.

Abstract P2-07-06: Multi-omics characterization of claudin-low breast tumors

Abstract Breast tumors display highly heterogeneous characteristics both at transcriptional level and in term of genomic landscape. We recently reported that the differentiation status of the cell-of-origin influences the genetic route toward tumorigenesis1. Indeed, mammary stem cells exhibit the intrinsic property to tolerate the oxidative stress inherent to the oncogenic transformation through the expression of a preemptive program driven by ZEB1, an epithelial-to-mesenchymal transition (EMT)-related transcription factor, and MSRB3, a methionine sulfoxide reductase. Thereby, ZEB1-expressing tumors exhibit low level of DNA damage associated with few genomic alterations and low level of TP53 mutations. Importantly, these tumors share several transcriptional characteristics and features with normal stem cells, and with Claudin-Low (CL) molecular subtype of breast cancers. In the present work, we attempt to decipher molecular traits of CL breast tumors through multi-omics analyses of publicly available databases. This global approach allows us to highlight various CL breast tumors features as clinical attributes, gene expression, copy number alterations (CNA), somatic mutations or drug responses by differential analyses of breast tumors and cancer cell lines. Preliminary results indicate that, independently of tumor purity, CL breast tumors are mostly diploids, present a paucity of genomic rearrangements and a lower mutation rate compared to other breast tumors. They mainly, but not exclusively, show basal features and belong to the integrative cluster 4 (CNA-devoid) described by Christina Curtis and colleagues2. Concerning gene expression, CL breast tumors exhibit a frequent activation of RAS signaling pathway, an observation consistent with their sensitivity to MAPK inhibitors. Other analyses are currently ongoing and aim to better understand the biology of CL breast tumors in order to improve both the diagnosis and the therapeutic strategy used. 1. Morel A-P et al. A stemness-related ZEB1-MSRB3 axis governs cellular pliancy and breast cancer genome stability. Nature Medicine. 2017 Apr 10. 2. Curtis C et al. The genomic and transcriptomic architecture of 2,000 breast tumours reveals novel subgroups. Nature. 2012 Apr 18. Citation Format: Pommier RM, Morel A-P, Tissier A, Thomas E, Kielbassa J, Tonon L, Sohier E, Viari A, Saintigny P, Puisieux A. Multi-omics characterization of claudin-low breast tumors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-07-06.