55 research outputs found
Effect of 2-(4-fluorophenylamino)-5-(2,4-dihydroxyphenyl)-1,3,4-thiadiazole on the molecular organisation and structural properties of the DPPC lipid multibilayers
AbstractInteractions and complex formation between lipids and biologically active compounds are crucial for better understanding of molecular mechanisms occurring in living cells. In this paper a molecular organisation and complex formation of 2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole (FABT) in DPPC multibilayers are reported. The simplified pseudo binary phase diagram of this system was created based on the X-ray diffraction study and fourier transform infrared spectroscopic data. The detailed analysis of the refraction effect indicates a much higher concentration of FABT in the polar zones during phase transition. Both the lipid and the complex ripple after cooling. It was found that FABT occupied not only the hydrophilic zones of the lipid membranes but also partly occupied the central part of the non polar zone. The infrared spectroscopy study reveals that FABT strongly interact with hydrophilic (especially PO2−) and hydrophobic (especially “kink” vibrations of CH2 group). The interactions of FABT molecules with these groups are responsible for changes of lipid multibilayers observed in X-ray diffraction study
Heterogeneous coupling of the Sumatran megathrust constrained by geodetic and paleogeodetic measurements
Geodetic and paleogeodetic measurements of interseismic strain above the Sumatran portion of the Sunda subduction zone reveal a heterogeneous pattern of coupling. Annual banding in corals provides vertical rates of deformation spanning the last half of the 20th century, and repeated GPS surveys between 1991 and 2001 and continuous measurements at GPS stations operated since 2002 provide horizontal velocities. Near the equator, the megathrust is locked over a narrow width of only a few tens of kilometers. In contrast, the locked fault zone is up to about 175 km wide in areas where great interplate earthquakes have occurred in the past. Formal inversion of the data reveals that these strongly coupled patches are roughly coincident with asperities that ruptured during these events. The correlation is most spectacular for rupture of the M_w 8.7 Nias-Simeulue earthquake of 2005, which released half of the moment deficit that had accumulated since its previous rupture in 1861, suggesting that this earthquake was overdue. Beneath the Mentawai islands, strong coupling is observed within the overlapping rupture areas of the great earthquakes of 1797 and 1833. The accumulated slip deficit since these events is slowly reaching the amount of slip that occurred during the 1833 earthquake but already exceeds the slip that occurred during the 1797 earthquake. Thus, rerupture of part of the Mentawai patch in September 2007 was not a surprise. In contrast, coupling is low below the Batu islands near the equator and around Enggano island at about 5°S, where only moderate earthquakes (M_w < 8.0) have occurred in the past two centuries. The correlation of large seismic asperities with patches that are locked during the interseismic period suggests that they are persistent features. This interpretation is reinforced by the fact that the large locked patches and great ruptures occur beneath persistent geomorphologic features, the largest outer arc islands. Depth- and convergence-rate-dependent temperature might influence the pattern of coupling, through its effect on the rheology of the plate interface, but other influences are required to account for the observed along-strike heterogeneity of coupling. In particular, subduction of the Investigator Fracture Zone could be the cause for the low coupling near the equator
The 2009 Samoa–Tonga great earthquake triggered doublet
Great earthquakes (having seismic magnitudes of at least 8) usually involve abrupt sliding of rock masses at a boundary between tectonic plates. Such interplate ruptures produce dynamic and static stress changes that can activate nearby intraplate aftershocks, as is commonly observed in the trench-slope region seaward of a great subduction zone thrust event1. The earthquake sequence addressed here involves a rare instance in which a great trench-slope intraplate earthquake triggered extensive interplate faulting, reversing the typical pattern and broadly expanding the seismic and tsunami hazard. On 29 September 2009, within two minutes of the initiation of a normal faulting event with moment magnitude 8.1 in the outer trench-slope at the northern end of the Tonga subduction zone, two major interplate underthrusting subevents (both with moment magnitude 7.8), with total moment equal to a second great earthquake of moment magnitude 8.0, ruptured the nearby subduction zone megathrust. The collective faulting produced tsunami waves with localized regions of about 12 metres run-up that claimed 192 lives in Samoa, American Samoa and Tonga. Overlap of the seismic signals obscured the fact that distinct faults separated by more than 50 km had ruptured with different geometries, with the triggered thrust faulting only being revealed by detailed seismic wave analyses. Extensive interplate and intraplate aftershock activity was activated over a large region of the northern Tonga subduction zone
A systematic review and meta-analysis of haematological malignancies in residents living near petrochemical facilities
Background
The petrochemical industry is a major source of hazardous and toxic air pollutants that are recognised to have mutagenic and carcinogenic properties. A wealth of occupational epidemiology literature exists around the petrochemical industry, with adverse haematological effects identified in employees exposed to ‘low’ concentrations of aromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylene). Releases from the petrochemical industry are also thought to increase the risk of cancer incidence in fenceline communities. However, this emerging and at times inconclusive evidence base remains fragmented. The present study’s aim was to conduct a systematic review and meta-analysis of epidemiological studies investigating the association between incidences of haematological malignancy and residential exposure to the petrochemical industry.
Methods
Epidemiological studies reporting the risk of haematological malignancies (Leukaemia, Hodgkin’s lymphoma, Non-Hodgkin’s lymphoma, and Multiple myeloma) were included where the following criteria were met: (i) Cancer incidence is diagnosed by a medical professional and coded in accordance to the International Classification of Diseases; (ii) A clear definition of fenceline communities is provided, indicating the proximity between exposed residents and petrochemical activities; and (iii) Exposure is representative of normal operating conditions, not emergency events. Two investigators independently extracted information on study characteristics and outcomes in accordance with PRISMA and MOOSE guidelines. Relative risks and their 95% confidence intervals were pooled across studies for the four categories of haematological malignancy, using a random effects meta-analysis.
Results
The systematic review identified 16 unique studies, which collectively record the incidence of haematological malignancies across 187,585 residents living close to a petrochemical operation. Residents from fenceline communities, less than 5 km from a petrochemical facility (refinery or manufacturer of commercial chemicals), had a 30% higher risk of developing Leukaemia than residents from communities with no petrochemical activity. Meanwhile, the association between exposure and rarer forms of haematological malignancy remains uncertain, with further research required.
Conclusions
The risk of developing Leukaemia appears higher in individuals living near a petrochemical facility. This highlights the need for further policy to regulate the release of carcinogens by industry
Rupture process of large earthquakes in the northern Mexico subduction zone
The Cocos plate subducts beneath North America at the Mexico trench. The northernmost segment of this trench, between the Orozco and Rivera fracture zones, has ruptured in a sequence of five large earthquakes from 1973 to 1985; the Jan. 30, 1973 Colima event ( M s 7.5) at the northern end of the segment near Rivera fracture zone; the Mar. 14, 1979 Petatlan event ( M s 7.6) at the southern end of the segment on the Orozco fracture zone; the Oct. 25, 1981 Playa Azul event ( M s 7.3) in the middle of the Michoacan “gap”; the Sept. 19, 1985 Michoacan mainshock ( M s 8.1); and the Sept. 21, 1985 Michoacan aftershock ( M s 7.6) that reruptured part of the Petatlan zone. Body wave inversion for the rupture process of these earthquakes finds the best: earthquake depth; focal mechanism; overall source time function; and seismic moment, for each earthquake. In addition, we have determined spatial concentrations of seismic moment release for the Colima earthquake, and the Michoacan mainshock and aftershock. These spatial concentrations of slip are interpreted as asperities; and the resultant asperity distribution for Mexico is compared to other subduction zones. The body wave inversion technique also determines the Moment Tensor Rate Functions ; but there is no evidence for statistically significant changes in the moment tensor during rupture for any of the five earthquakes. An appendix describes the Moment Tensor Rate Functions methodology in detail.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43169/1/24_2004_Article_BF00875970.pd
Three-dimensional viscoelastic interseismic deformation model for the Cascadia subduction zone
Designing of compressed elements made of aluminium with the use of Eurocodes and calculation software
Właściwa ocena stateczności ogólnej elementu oraz prawidłowe wyznaczenie siły krytycznej i nośności z uwagi na wyboczenie prętów poddanych działaniu osiowej siły ściskającej decydują o poprawnym zaprojektowaniu ustroju prętowego. Opisane zagadnienia związane są z projektowaniem prętów ściskanych osiowo według Eurokodu 9, wykonanych z kształtowników aluminiowych. Prezentowany artykuł zwraca uwagę na różnice wynikające z niewłaściwego stosowania programów do wymiarowania konstrukcji aluminiowych w wypadkach, gdy programy nie zawierają procedur Eurokodu 9, a jedynie bazę danych materiałowych wyrobów aluminiowych.Adequate assessment of general stability of the element as well as appropriate determination of a critical force and load-bearing capacity due to buckling of bars subject to the impact of axial compressing force determine the appropriate designing of the bar system. The issues described in the article are connected with designing of axially compressed bars according to eurocode 9, made using aluminium shape sections. The article pays attention to the differences resulting from improper use of software for sizing aluminium constructions in cases where programmes do not include eurocode 9 procedures, and only a material database of aluminium products
Crosslinking process and properties of unconventional blends of chloroprene rubber and partially hydrogenated acrylonitrile-butadiene rubber
Zbadano właściwości niekonwencjonalnych mieszanin podatnego na krystalizację i termosieciowanie kauczuku chloroprenowego (CR) z częściowo uwodornionym (> 95 % mol) kauczukiem butadienowo-akrylonitrylowym (THNBR). Mieszaniny sporządzano stosując metodę reaktywnego przetwórstwa, połączonego z dynamicznym, selektywnym termosieciowaniem CR, a następnie sieciowania w temperaturze 433 K disiarczkiem tetrametylotiuramu (TMTD), w obecności ZnO. Zbadano kinetykę sieciowania oraz właściwości mechaniczne przy rozciąganiu oraz metodą mikroskopii sił atomowych (AFM) określono morfologię mieszanin, a na podstawie pęcznienia równowagowego w rozpuszczalnikach stopień ich usieciowania. Stwierdzono, że mieszaniny CR/THNBR, zawierające 25—45 phr uprzednio termousieciowanego CR, a następnie usieciowane za pomocą TMTD/ZnO, charakteryzują się wyższym stopniem usieciowania oraz większą wytrzymałością na rozciąganie niż mieszaniny zawierające tylko termousieciowany CR.The properties of unconventional elastomer blends of crystallizable and thermally crosslinkable chloroprene rubber (CR) with partially hydrogenated (> 95 mol %) acrylonitrile-butadiene rubber (THNBR) were investigated. The blends were prepared by reactive processing combined with dynamic, selective thermal curing of CR and subsequent crosslinking with tetramethylthiuram disulfide (TMTD) and zinc oxide at 433 K. The crosslinking kinetics and tensile mechanical properties of the produced blends were studied. The morphology of blends was investigated using atomic force microscopy (AFM) method and the degree of crosslinking was determined by equilibrium swelling in selected solvents. It has been found that CR/THNBR blends containing 25—45 phr thermally cured CR, subsequently crosslinked with TMTD/ZnO system are characterized by higher crosslinking degree and higher tensile strength than CR/THNBR blends with only thermally cured CR
Faults of designing and using metal-glass structures
The aim of the article is taking a closer look at the problems concerning technical condition assessment with regard to correctness of project goals of structures metal-glass facade. Made is reference to the manner of their execution and proper functioning. The issue of accordance to good engineering practice of adapting changes in the system and adjusting the fitted solutions as reccomended by the producers. Above mentioned issues were dealt with given an example of high-rise building with applied curtain wall and a residential building where a filling structure is mounted
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