Characterization of fractured rock in the vicinity of tunnels by the swept impact seismic technique

The diversity of the applications of high-resolution seismics requires investigations in the range of hundreds of meters to be performed in very diverse conditions. We found the swept impact seismic technique (SIST) to be a viable solution for high-resolution surveys in hard rocks. Swept impact seismic technique combines the Vibroseis swept frequency and the Mini-Sosie multi-impact ideas. Several variations of the method have been studied leading to improved resolution and efficiency. The development was partly funded by the Finnish Center for Technical Development (TEKES) and partly by the French National Agency for the Management of Radioactive Waste—ANDRA. A test programme was carried out at the Grimsel test site, operated by NAGRA—the Swiss National Cooperative for the Disposal of Radioactive Waste. Measurements were also carried out with single-pulse sources, but data of acceptable quality could not be obtained. Surface and tunnel-wall, as well as borehole SIST sources have been developed and tested. The ability of the seismic techniques to detect and characterize rock discontinuities was proven by investigating a rock block delimited by two parallel boreholes and a tunnel perpendicular to them, involving source–detector distances of 100–200 m. The characterization included the determination of the 3-D positions and orientations of rock features and the tomographic mapping of seismic velocities.     

Polycyclic aromatic hydrocarbon-DNA adducts in human placenta and modulation by CYP1A1 induction and genotype

This study investigated the relationship in human placenta between polycyclic aromatic hydrocabon (PAH)-DNA adduct levels and two biomarkers of cytochrome P4501A1 (CYP1A1): gene induction evidenced by CYP1A1 mRNA, and a genetic polymorphism, the CYP1A1 MspI RFLP. CYP1A1 codes for an inducible enzyme system that catalyzes the bioactivation of PAHs. Prior research found a high correlation in human lung tissue between CYP1A1 activity and DNA damage from PAHs. The CYP1A1 Mspi RFLP has been linked in some studies to risk of lung cancer. The relationships in human placenta between DNA damage, CYP1A1 activity and genotype have not been well characterized and may be relevant to risks from transplacental PAH exposure. The study cohort consisted of 70 newborns from Krakow, Poland, a city with elevated air pollution, and 90 newborns from nearby Limanowa, an area with lower air pollution but greater indoor coal use. Contrary to results seen previously in lung tissue, CYP1A1 mRNA was not significantly correlated with PAH-DNA adduct levels in the placenta. Smoking (self-reported maternal and infant plasma cotinine) was significantly associated with CYP1A1 mRNA levels (P < 0.01), but not with PAH-DNA adduct levels. Placental PAH-DNA adduct levels were significantly higher in infants with the CYP1A1 MspI restriction site compared with infants without the restriction site (P < 0.01), implicating a genetic factor in inter-individual variation in DNA damage in human placenta. Further studies are needed to determine the relevance of this finding to risk of transplacental carcinogenesis.     

Mutational activation of the Cpx signal transduction pathway of Escherichia coli suppresses the toxicity conferred by certain envelope-associated stresses

Anticipation and suspicion are critical aspects to any discussion of intrauterine adhesions. Curettage between the second and fourth week postpartum is more likely to cause adhesions than is any other endometrial trauma. Infertility, recurrent abortion, or menstrual aberrations after any uterine trauma should cause the physician to suspect the presence of intrauterine adhesions. Hysterosalpingography and hysteroscopy are the ideal methods to make the diagnosis of IUA, and the latter is the safest, least traumatic, and most precise method of treating adhesions. The addition of an intrauterine splint and high-dose estrogen therapy completes the therapeutic approach. Before attempting conception the cavity should be inspected to verify its normality.     

A comprehensive investigation of dye–chitosan blended films for green chemistry applications

In this paper, the ability of chitosan film to remove dyestuff from wastewater was evaluated for environmental applications, using three commercial direct azo dyes. Two chitosan films were adopted: the standard one prepared following a well‐known procedure to form it, and a novel one, with a weakly acidic character. Moreover, to improve the adsorption process, the hydrophobic character of the films was investigated. The pH of the dye solutions was also changed, showing an excellent ability in dye removal at pH 12. The films were characterized by means of spectroscopic and morphologic methods to better understand the nature of interactions between dyes and chitosan chains. Swelling ratio measurements were also performed. All analyses suggest that all dyes showed a strong affinity to chitosan polymer chains, with the presence of extended hydrogen bonds and Van der Waals forces perturbing the chitosan network. Interestingly, very good results were obtained in recycling experiments related to the dyeing capacities of chitosan blended films in the presence of textiles. An ecofriendly application is thus presented in this paper. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45945.     

Scanning electrochemical microscopy of the photosynthetic reaction center of Rhodobacter sphaeroides in different environmental systems

The present work uses a scanning electrochemical microscopy technique to study systems containing the membrane-bound reaction center protein (RC) from the purple photosynthetic bacteria Rhodobacter spheroides to chromatophores (spherical reorganization of cell membrane following its mechanical rupture) and liposomes (reconstituted membrane systems at lower degree of complexity). Scanning electrochemical microscopy is a useful tool to investigate redox processes involving a RC, because the effective heterogeneous rate constants for the redox reaction with different mediators can be measured. The technique is also able to provide information on the role of the outer cell membrane permeation on the kinetics of the electron-transfer processes and to obtain more insight into the nature of the species involved.     

Seismic characterization of fracturing at the Äspö Hard Rock Laboratory, Sweden, from the kilometer scale to the meter scale

In 1986, the Swedish Nuclear Fuel and Waste Management Co. (SKB) decided to build an underground research laboratory, the Äspö Hard Rock Laboratory (HRL). The Äspö HRL offers the possibility to test and demonstrate a full site investigation sequence. As part of this work, various seismic techniques were tested and demonstrated, from the kilometer to the meter scale. The preliminary investigation stage comprised surface reflection profiling and VSP. The VSP measurements, though limited to one borehole, played an important role in defining the site model. Shallow reflection surveys in crystalline rock have been judged as basically feasible, but further development is required to reduce costs. During the construction of the laboratory, the objective of the seismic investigations was to check and refine the site model. Within the zone of excavation disturbance experiment project, seismic tomographic analyses were made for P- and S- wave velocity and attenuation, at 5–15 m scale. Crosshole reflection imaging was also performed. The tracer retention understanding experiments project also included transmission and reflection tomography but on a 100–300 m scale. For the experiments where both transmission and reflection measurements were processed, the seismic surveys also produced information regarding the intrinsic mechanical properties of the rock besides inferring a geometrical model of the rock structures.     

Scavenging of reactive oxygen species by melatonin

Monocytes adherent to implanted biomaterials differentiate into macrophages while synthesizing large amounts of degradative enzymes, including cholesterol esterase (CE), which previously has been shown to degrade poly(urethane)s. Human peripheral blood monocytes were cultured on tissue culture grade polystyrene (PS), and two model poly(urethane)s were synthesized from (1) polycaprolactone (PCL) and (2) polytetramethylene oxide (PTMO), both with 2,4-toluene diisocyanate (TDI) and ethylene diamine (ED). The increase in CE and total protein per cell were measured on days 8 and 28 in culture and normalized to the DNA content per cell. At day 8 there consistently were fewer cells remaining on the PTMO-based polymer than on the PCL-based polymer or the PS (p < 0.05). When comparing day 28 to day 8, there was more CE activity and protein per cell on all materials. However, there was a disproportionate synthesis of CE per mg of total protein on PS and TDI/PCL/ED whereas on PTMO there was not. Significantly, there was more protein and CE per cell on PTMO than on PS or TDI/PCL/ED (p < 0.05). This in vitro model system of the chronic phase of inflammation has shown that it is possible to culture monocytes for a month and assess the material surface itself as a potent activator of the differentiation into macrophages without secondary stimulation. Since CE has been shown to degrade poly(ether and ester)-based poly(urethane)s, the differential production of this enzyme relative to the total protein on different surfaces may impact on the potential long-term biostability of an implanted material.     

Determination of rockmass quality by the crosshole seismic method

Bulletin of Engineering Geology and the Environment - The purpose of the method is to map velocities of P- and S-waves, elastic moduli and attenuation coefficients in the region between two...