We describe artificial neural networks used to predict the velocity and frequency of ground vibrations caused by blasting in an open-pit mine. The aim was to predict peak particle velocity and ...frequency of ground vibrations from information on the physical and mechanical properties of the rock mass, the characteristics of the explosive and blasting design. Some the parameters that could possibly have a bearing on the prediction were considered. A distinction was drawn between two kinds of parameters: those defining the surroundings in which the wave is propagated (rock type, rock mass, distance to be covered by the wave and significant subsoil discontinuities) and those defining the energy of the wave (the kind of explosive, explosive charge and blasting geometry and sequence).
Vibrations were monitored using seismographs capable of capturing vibration data and transforming them into acceleration and frequency terms. To validate this methodology, the predictions obtained were compared with those obtained using conventional statistical methods. The correlation coefficients obtained for our methodology was 0.98 for peak particle velocity and 0.95 for frequency, compared to 0.50 and 0.15, respectively, for Multiple Linear Regression.
We studied the surface properties of Aβ(1–40) amyloid peptides mixed with 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) (liquid state) or 1,2-disteraoyl-phosphatidylcholine (DSPC) (solid state) ...phospholipids by using nanostructured lipid/peptide films (Langmuir monolayers). Pure Aβ(1–40) amyloid peptides form insoluble monolayers without forming fibril-like structures. In a lipid environment phospholipid/Aβ(1–40) peptide mixtures, we observed that both miscibility and stability of the films depend on the peptide content. At low Aβ(1–40) amyloid peptide proportion (from 2.5 to 10% of peptide area proportion), we observed the formation of a fibril-like structure when mixed only with POPC lipids. The stability acquired by these mixed films is within 20–35 mN·m–1 compatible with the equivalent surface pressure postulated for natural biomembranes. Fibrils are clearly evidenced directly from the monolayers by using Brewster angle microscopy. The so-called nanostructured fibrils are thioflavin T positive when observed by fluorescence microscopy. The amyloid fibril network at the surface was also evidenced by atomic force microscopy when the films are transferred onto a mica support. Aβ(1–40) amyloid mixed with the solid DSPC lipid showed an immiscible behavior in all peptide proportions without fibril formation. We postulated that the amyloid fibrillogenesis at the membrane can be dynamically nano-self-triggered at the surface by the quality of the interfacial environment, that is, the physical state of the water–lipid interface and the relative content of amyloid protein present at the interface.
Alzheimer’s disease (AD) is related to the fibrillation of the Aβ peptides at neuronal membranes, a process that depends on the lipid composition and may impart different physical states to the ...membrane. In the present work, we study the properties of the Aβ peptide when mixed with a zwitterionic lipid (DMPC), using the Langmuir monolayer technique as an approach to control membrane physical conditions. First, we build on previous characterizations of pure Aβ monolayers and observe that, in addition to high shear, these films present a pronounced compressional hysteresis. When Aβ is assembled with DMPC in a binary film, the resulting membranes become heterogeneous, with a peptide-enriched phase distributed in a network-like pattern, and they exhibit a lateral transition that depends on the Aβ content. At lower peptide proportions, the films segregate into two well-defined phases: one consisting of lipids and another enriched with peptides. The reflectivity of these phases differs from that obtained for pure Aβ films. Thus, the formed fibers effectively cover most of the interface area and remain stable at higher pressures (from 20 to 30 mN m–1 depending on Aβ content) compared to pure peptide films (17 mN m–1). Furthermore, such structures induce a compressional hysteresis in the film, similar to that of pure peptide films (which is nonexistent in the pure lipid monolayer), even at low peptide proportions. We claim that the mechanical properties at the interface are governed by the size of the fibril-like structures. Based on the low molar fractions and surface packing at which these phenomena were observed, we postulate that as a consequence of peptide intermolecular interactions, Aβ may have drastic effects on the molecular arrangement and mechanical properties of a lipid membrane.
Pancreatic ductal adenocarcinoma (PDAC) is one of the most intractable and devastating malignant tumors. Epigenetic modifications such as DNA methylation and histone modification regulate tumor ...initiation and progression. However, the contribution of histone variants in PDAC is unknown. Here, we demonstrated that the histone variant H2A.Z is highly expressed in PDAC cell lines and PDAC patients and that its overexpression correlates with poor prognosis. Moreover, all three H2A.Z isoforms (H2A.Z.1, H2A.Z.2.1, and H2A.Z.2.2) are highly expressed in PDAC cell lines and PDAC patients. Knockdown of these H2A.Z isoforms in PDAC cell lines induces a senescent phenotype, cell cycle arrest in phase G2/M, increased expression of cyclin-dependent kinase inhibitor CDKN2A/p16, SA-β-galactosidase activity and interleukin 8 production. Transcriptome analysis of H2A.Z-depleted PDAC cells showed altered gene expression in fatty acid biosynthesis pathways and those that regulate cell cycle and DNA damage repair. Importantly, depletion of H2A.Z isoforms reduces the tumor size in a mouse xenograft model in vivo and sensitizes PDAC cells to gemcitabine. Overexpression of H2A.Z.1 and H2A.Z.2.1 more than H2A.Z.2.2 partially restores the oncogenic phenotype. Therefore, our data suggest that overexpression of H2A.Z isoforms enables cells to overcome the oncoprotective barrier associated with senescence, favoring PDAC tumor grow and chemoresistance. These results make H2A.Z a potential candidate as a diagnostic biomarker and therapeutic target for PDAC.
The hydrosilylation of CO2 with different silanes such as HSiEt3, HSiMe2Ph, HSiMePh2, HSiMe(OSiMe3)2, and HSi(OSiMe3)3 in the presence of catalytic ammounts of the iridium(III) complex ...Ir(H)(CF3CO2)(NSiN*)(coe) (1; NSiN*=fac‐bis‐(4‐methylpyridine‐2‐yloxy); coe=cis‐cyclooctene) has been comparatively studied. The activity of the hydrosilylation catalytic system based on 1 depends on the nature of the reducing agent, where HSiMe(OSiMe3)2 has proven to be the most active. The aforementioned reactions were found to be highly selective toward the formation of the corresponding silylformate. It has been found that using 1 as catalyst precursor above 328 K decreases the activity through a thermally competitive mechanistic pathway. Indeed, the reduction of the ancillary trifluoroacetate ligand to give the corresponding silylether CF3CH2OSiR3 has been observed. Moreover, mechanistic studies for the 1‐catalyzed CO2‐hydrosilylation reaction based on experimental and theoretical studies suggest that 1 prefers an inner‐sphere mechanism for the CO2 reduction, whereas the closely related Ir(H)(CF3SO3)(NSiN)(coe) catalyst, bearing a triflate instead of trifluoroacetate ligand, follows an outer‐sphere mechanism.
Too hot to go outside: A mechanism explaining the iridium‐catalyzed hydrosilylation of CO2 is proposed. It was found that the 1‐catalyzed CO2‐hydrosilylation depends on the nature of the silane. Moreover, the phenomenon of decreasing activity and selectivity of the catalytic system with increasing reaction temperature has been clarified using computational methods.
The aim of this work was to (i) determine the chemical composition of the essential oils (EOs) of five spices widely cultivated in Egypt as: Fennel (
Foeniculum vulgare), parsley (
Petroselinum ...crispum), lavender (
Lavandula officinalis), black cumin (
Nigella sativa) and thyme (
Thymus vulgaris); (ii) determine the total phenolic compound (TPC) content (iii) determine the antioxidant activity of the Egyptian essentials oils by means of three different antioxidant test and (iv) determine the effectiveness of the Egyptian essentials oils on the inhibition of the growth of some indicators of spoilage bacteria strains. There is a great variability in the chemical composition of EOs obtained from the five Egyptian aromatic plants. Thyme EO had the highest content of total phenols (913.17 mg GAE/L). Black cumin (highest % of inhibition of DPPH radical: 95.89% and highest FRAC values 3.33 mmol/L Trolox) and thyme (highest % of inhibition of TBARS: 80.76) essential oils presented the best antioxidant profile. Only the essential oil of thyme showed inhibitory effects on the three tested bacteria at all added doses.
Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2 , CO, and planetary boundary layer height ...(PBLH) measurements recorded during the CalNex-LA (CARB et al., 2008) ground campaign of 15 May-15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA). This affordable and simple technique, validated by carbon isotope observations and WRF-STILT (Weather Research and Forecasting model - Stochastic Time-Inverted Lagrangian Transport model) predictions, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin over the entire diurnal cycle. During CalNex-LA, local fossil fuel combustion contributed up to ~50% of the observed CO2 enhancement overnight, and ~100% of the enhancement near midday. This suggests that sufficiently accurate total column CO2 observations recorded near midday, such as those from the GOSAT or OCO-2 satellites, can potentially be used to track anthropogenic emissions from the LA megacity.
A field tracer test and two-dimensional numerical modeling were used to analyze the scalars transport in an 8.0-km reach of the Salado River (Santa Fe) where urban and industrial pollutants are ...released. Rhodamine WT was injected as tracer, and its concentration was recorded in three sections located at 1000, 3000, and 4500 m. SisBaHiA numerical model was used to represent the hydrodynamics and the scalar transport. The transverse and longitudinal dispersion coefficients obtained from fitting the observed concentration curves were in the range of 0.0078–0.037 m
2
/s and 0.25–1.46 m
2
/s, respectively. The best fit was achieved with the classical ratios:
K
L
/
u
∗
H
=
5.93
and
K
T
/
u
∗
H
=
0.15
. Both measurements and simulation showed the presence of the tracer in the banks at 1000 m from the injection point, but the particle transport model revealed the heterogeneous distribution of the tracer at the section width in the whole study reach. The maximum concentration curves were located near of the banks, which could be due to the fact that the concentration was maximized when the particle cloud reaches these shallower zones. The complex flow pattern caused by bathymetric irregularities and sharps bends largely explains the deformation of the concentration curves. The large spatial variations of the line of maximum velocity caused the particles to evolve with increasing relative displacements to each other. While that in S1 zone, the particles and concentration curves showed typical pattern with relatively concentric concentration isolines towards the middle of the section, the S2 and S3 zones showed a large particles dispersion with long tails, mainly on the left bank.
To describe the incidence and progression of radiographic and symptomatic hand osteoarthritis (rHOA and sxHOA) in a large community-based cohort.
Data were from the Johnston County OA Project ...(1999–2015, 12 ± 1.2 years follow-up, age 45+). Participants had bilateral hand radiographs each visit, read for Kellgren–Lawrence grade (KLG) at 30 joints. We defined rHOA as KLG ≥2 in ≥1 joint. SxHOA was defined in a hand/joint with rHOA and self-reported symptoms or tenderness on exam. Incidence was assessed in those without, while progression was assessed in those with, baseline rHOA. Proportions or medians are reported; differences by sex and race were assessed using models appropriate for dichotomous or continuous definitions, additionally adjusted for age, education, body mass index (BMI), and weight change.
Of 800 participants (68% women, 32% African American, mean age 60 years), 327 had baseline rHOA and were older, more often white and female, than those without rHOA (n = 473). The incidence of HOA was high, for rHOA (60%) and for sxHOA (13%). Women were more likely than men to have incident HOA, particularly for distal interphalangeal joint radiographic osteoarthritis (DIP rOA) (adjusted odds ratios (aOR) 1.60 95% confidence intervals (95% CI) 1.03, 2.49) and sxHOA (aOR 2.98 1.50, 5.91). Progressive HOA was more similar by sex, although thumb base rOA progressed more frequently in women than in men (aOR 2.56 1.44, 4.55). Particularly HOA incidence, but also progression, was more frequent among whites compared with African Americans.
This study provides much needed information about the natural history of HOA, a common and frequently debilitating condition, in the general population.
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