2,335 research outputs found
Warm molecular gas temperature distribution in six local infrared bright Seyfert galaxies
We simultaneously analyze the spectral line energy distributions (SLEDs) of
CO and H2 of six local luminous infrared (IR) Seyfert galaxies. For the CO
SLEDs, we used new Herschel/SPIRE FTS data (from J=4-3 to J=13-12) and
ground-based observations for the lower-J CO transitions. The H2 SLEDs were
constructed using archival mid-IR Spitzer/IRS and near-IR VLT/SINFONI data for
the rotational and ro-vibrational H2 transitions, respectively. In total, the
SLEDs contain 26 transitions with upper level energies between 5 and 15000 K. A
single, constant density, model (n ~ 10 cm) with a
broken power-law temperature distribution reproduces well both the CO and H2
SLEDs. The power-law indices are ~ 1-3 for warm molecular gas (20 K <
T 100 K). We show that
the steeper temperature distribution (higher ) for hot molecular gas can
be explained by shocks and photodissociation region (PDR) models, however, the
exact values are not reproduced by PDR or shock models alone and a
combination of both is needed. We find that the three major mergers among our
targets have shallower temperature distributions for warm molecular gas than
the other three spiral galaxies. This can be explained by a higher relative
contribution of shock excitation, with respect to PDR excitation, for the warm
molecular gas in these mergers. For only one of the mergers, IRASF 05189-2524,
the shallower H2 temperature distribution differs from that of the spiral
galaxies. The presence of a bright active galactic nucleus in this source might
explain the warmer molecular gas observed.Comment: A&A in press; 15 pages, 7 figures. Fixed several typo
Finite element analysis of stress extent at peri-implant bone surrounding external hexagon or Morse taper implants
The purpose of the present study was to evaluate the distribution of stresses and consequent bone volume affected surrounding external hexagon or Morse taper dental implant systems by finite element analysis.The authors acknowledge the support provided by the Dept. of Mechanical Engineering at the University of Minho (Portugal) and by Drawing 3D implicit Finite Element Code (DD3imp, Portugal). This study was supported by FCT-Portugal (EXCL/EMS-TEC/0460/2012; UID/EEA/04436/2013, NORTE-01-0145-FEDER-000018 - HAMaBICo), CNPq-Brazil (PVE/CAPES/CNPq/407035/2013-3).info:eu-repo/semantics/publishedVersio
Threading holder based on axial metal cylinder pins to reduce tap risk during reversion instant
Internal thread profiles are used widely in manufacturing processes with the aim of assembling/disassembling different components during maintenance activities from the aeronautics sector until common industrial parts. The threading process is one of the last operations carried out to obtain those components, and consequently, it is an operation of high added value. Threading is a complex operation that must carefully synchronize the rotation with the feed movements to avoid tool breakage during the instant of tapping reversion stage. In order to avoid this risk, several toolholders were developed present in the literature but deficiencies in terms of stability and productivity. Therefore, in this work, a new toolholder is proposed in which the common springs used to mitigate the lack of perfect synchronization between rotation and feed movements are replaced by elastic metal pins achieving a torsional compliance toolholder. The results show that the use of the proposed toolholder implies not only a productivity increase but also a surface integrity improvement as well as a stress reduction that the cutting tap is subjected and thus, achieving a substantial improvement in the current tapping processes. In particular, the use of the proposed toolholder implied a 75% reduction of the maximum stress achieved in the reversal instant, improving 20% tool life with an increase of 30% cutting speed. Therefore, the use of the proposed toolholder implies a substantial improvement in the current tapping processes
Effects of laser-textured on rake face in turning PCD tools for Ti6Al4V
The demand inherent to the aeronautical industry in terms of productivity and quality requirements leads to develop new cutting tools. Hence, PCD tools meet the requirements in productivity while machining low machinability aeronautical alloys such as Ti6Al4V. Tool chipbreakers play a considerable role in terms of tool life. However, due to the extreme conditions (temperature and pressure) required to manufacture PCD tools, any complex geometry on tool rake faces is not viable, so chipbreakers are not possible, except for those external to inserts.
This work proposes a groove-type laser engraved chipbreaker design and a manufacturing methodology, with experimental validation on turning a Ti6Al4V workpiece. The so-manufactured chipbreakers achieve titanium alloy chip fragmentation, making easy chip removal from the cutting zone.
A set of experiments involving various laser parameters to characterize the PCD depth and surface integrity and experimental validation for those chipbreakers designs were carried out in finishing cutting conditions. The optimum parameters for the engraving of PCD were found, obtaining satisfactory breakage of titanium chips. Chip length was always below 17.29 mm.Authors are grateful to Basque government group IT IT1337- 19, the Ministry of Mineco REF DPI2016-74845-R and PID2019- 109340RB-I00, and the UPV/EHU itself for the financial aid for the pre-doctoral grants PIF 19/96
Reconstitution of respiratory complex I on a biomimetic membrane supported on gold electrodes
For the first time, respiratory complex I has been reconstituted on an electrode preserving its structure and activity. Respiratory complex I is a membrane-bound enzyme that has an essential function in cellular energy production. It couples NADH:quinone oxidoreduction to translocation of ions across the cellular (in prokaryotes) or mitochondrial membranes. Therefore, complex I contributes to the establishment and maintenance of the transmembrane difference of electrochemical potential required for adenosine triphosphate synthesis, transport, and motility. Our new strategy has been applied for reconstituting the bacterial complex I from Rhodothermus marinus onto a biomimetic membrane supported on gold electrodes modified with a thiol self-assembled monolayer (SAM). Atomic force microscopy and faradaic impedance measurements give evidence of the biomimetic construction, whereas electrochemical measurements show its functionality. Both electron transfer and proton translocation by respiratory complex I were monitored, simulating in vivo conditions. © 2014 American Chemical Society.This work was funded by the Spanish MINECO (project CTQ2012-32448) and by Fundação para a Ciência e a Tecnologia (PTDC/BBB-BQB/2294/2012 to M.M.P.). The work was also supported by Fundação para a Ciência e a Tecnologia through grant # PEst-OE/EQB/LA0004/2011. M.P. and O.G.-S. acknowledge the Ramon y Cajal and the FPI programs respectively from the Spanish MINECO. A.P.B. is recipient of a grant from Fundação para a Ciência e a Tecnologia (SFRH/BPD/80741/2011).Peer Reviewe
A brain-sparing diphtheria toxin for chemical genetic ablation of peripheral cell lineages.
Conditional expression of diphtheria toxin receptor (DTR) is widely used for tissue-specific ablation of cells. However, diphtheria toxin (DT) crosses the blood-brain barrier, which limits its utility for ablating peripheral cells using Cre drivers that are also expressed in the central nervous system (CNS). Here we report the development of a brain-sparing DT, termed BRAINSPAReDT, for tissue-specific genetic ablation of cells outside the CNS. We prevent blood-brain barrier passage of DT through PEGylation, which polarizes the molecule and increases its size. We validate BRAINSPAReDT with regional genetic sympathectomy: BRAINSPAReDT ablates peripheral but not central catecholaminergic neurons, thus avoiding the Parkinson-like phenotype associated with full dopaminergic depletion. Regional sympathectomy compromises adipose tissue thermogenesis, and renders mice susceptible to obesity. We provide a proof of principle that BRAINSPAReDT can be used for Cre/DTR tissue-specific ablation outside the brain using CNS drivers, while consolidating the link between adiposity and the sympathetic nervous system
Prediction of crop coefficients from fraction of ground cover and height. Background and validation using ground and remote sensing data
ReviewThe current study aims at reviewing and providing advances on methods for estimating and applying crop coefficients
from observations of ground cover and vegetation height. The review first focuses on the relationships between single
Kc and basal Kcb and various parameters including the fraction of ground covered by the canopy (fc), the leaf area index
(LAI), the fraction of ground shaded by the canopy (fshad), the fraction of intercepted light (flight) and intercepted
photosynthetic active radiation (fIPAR). These relationships were first studied in the 1970’s, for annual crops, and later,
in the last decennia, for tree and vine perennials. Research has now provided a variety of methods to observe and
measure fc and height (h) using both ground and remote sensing tools, which has favored the further development of Kc
related functions. In the past, these relationships were not used predictively but to support the understanding of
dynamics of Kc and Kcb in relation to the processes of evapotranspiration or transpiration, inclusive of the role of soil
evaporation. Later, the approach proposed by Allen and Pereira (2009), the A&P approach, used fc and height (h) or LAI
data to define a crop density coefficient that was used to directly estimate Kc and Kcb values for a variety of annual and
perennial crops in both research and practice. It is opportune to review the A&P method in the context of a variety of
studies that have derived Kc and Kcb values from field measured data with simultaneously observed ground cover fc and
height. Applications used to test the approach include various tree and vine crops (olive, pear, and lemon orchards and
vineyards), vegetable crops (pea, onion and tomato crops), field crops (barley, wheat, maize, sunflower, canola, cotton
and soybean crops), as well as a grassland and a Bermudagrass pasture. Comparisons of Kcb values computed with the A
&P method produced regression coefficients close to 1.0 and coefficients of determination≥0.90, except for orchards.
Results indicate that the A&P approach can produce estimates of potential Kcb, using vegetation characteristics alone,
within reasonable or acceptable error, and are useful for refining Kcb for conditions of plant spacing, size and density
that differ from standard values. The comparisons provide parameters appropriate to applications for the tested crops.
In addition, the A&P approach was applied with remotely sensed fc data for a variety of crops in California using the
Satellite Irrigation Management Support (SIMS) framework. Daily SIMS crop ET (ETc-SIMS) produced Kcb values using
the FAO56 and A&P approaches. Combination of satellite derived fc and Kcb values with ETo data from Spatial CIMIS
(California Irrigation Management Information System) produced ET estimates that were compared with daily actual
crop ET derived from energy balance calculations from micrometeorological instrumentation (ETc EB).Results produced
coefficients of regression of 1.05 for field crops and 1.08 for woody crops, and R2 values of 0.81 and 0.91, respectively.
These values suggest that daily ETc-SIMS -based ET can be accurately estimated within reasonable error and that the A&P
approach is appropriate to support that estimation. It is likely that accuracy can be improved via progress in remote
sensing determination of fc. Tabulated Kcb results and calculation parameters are presented in a companion paper in this
Special Issueinfo:eu-repo/semantics/publishedVersio
Estimación de las necessidades hídricas de la papaya utilizando la aproximación de los coeficientes culturales duales
The use of irrigation in the cultivation of papaya is increasing in recent years. Thus, there is the need for
improved knowledge of the most appropriate irrigation scheduling practices to be adopted as well as the more
adequate estimation of crop water requirements. With this objective, the simulation model SIMDualKc was
adopted and calibrated. The model performs the calculation of crop evapotranspiration (ETc) with the
methodology of the dual crop coefficient (Kc = Kcb + Ke), i.e., using a basal crop coefficient to estimate crop
transpiration and an evaporation coefficient to estimation soil water evaporation. The research was conducted at
the Experimental Station of Irrigation and Drainage, located in Alquízar, Havana, Cuba. The experiments were
carried out between March and November 1997 with the papaya var. "Maradol red". The calibration consisted in
searching the crop factors relative to the different stages of crop development that minimize the differences
between the simulated and observed soil moisture content. Various goodness of fit indicators were used to
evaluate the model predictions. It can be concluded that the model was properly calibrated and can be used to
generate alternative irrigation schedules that improve water use and productivity of papaya in the considered soil
and climate condition
Physicochemical characterization and antimicrobial activity of mucus of Achatina fulica
Introducción: El caracol gigante africano Achatina fulica es reconocido como una plaga que afectala biodiversidad, la Salud Pública y la productividad. Sin embargo, se ha demostrado que su secreción mucosa tiene propiedades cosméticas, cicatrizantes y antimicrobianas. Objetivo: Determinar las características físico-químicas y evaluar la actividad antimicrobiana de la secreción mucosa de Achatina fulica. Metodología: Se hicieron pruebas bioquímicas para la determinación cualitativa y cuantitativa de glúcidos, proteínas y lípidos. Se determinó el contenido de Calcio, Potasio, cloruros, Sodio y Magnesio. Se midieron los parámetros de conductividad eléctrica, potencial óxido-reducción, saturación de oxígeno, oxígeno total disuelto, pH, sólidos disueltos totales. Se realizó un ensayo de actividad antibacteriana por la técnica de microdilución en caldo. Resultados: Se encontraron glúcidos en concentraciones de 582 μg/mL en la fracción soluble y de 62.1 μg/mL en la fracción de mucinas, y proteínas en concentraciones de 836 μg/mL en la fracción soluble y de 1413 μg/mL en la fracción de mucinas. Se observó actividad antimicrobiana frente a las tres cepas ensayadas. Streptococcus agalactiae alcanzó un MIC90 a una concentración de 3,6 mg/mL con la fracción de mucinas; Staphylococcus aureus resistente a meticilina tuvo un MIC50 de 3,3 mg/mL y Escherichia coli un MIC 70 de 3.8 mg/mL. Conclusiones: Se reportan por primera vez las características físicas y los oligoelementos presente en la secreción de Achatina fulica. La actividad antibacteriana obtenida frente a cepas Gram positivas y Gram negativas plantea la necesidad de realizar estudios para purificar las moléculas con dicha actividad, conocer los mecanismos de acción y establecer la inocuidad, entre otros.Introduction: The giant African snail Achatina fulica is recognized as a scourge affecting biodiversity,public health and productivity. However, it has been shown that the mucus has cosmetic, healing and antimicrobial properties. Objective: Determine physico-chemical characteristics and evaluate the antimicrobial activity of the mucus. Methodology: Qualitative and quantitative determinations of carbohydrates, proteins and lipids were made by biochemical tests. Using multiparameter meter parameters of electrical conductivity, redox potential, oxygen saturation, the total dissolved oxygen, pH, total dissolved solids were measured. Content of Calcium, Potassium, chloride, Sodium and Magnesium was determined. Antibacterial activity assay was performed by broth microdilution method against Gram positive and Gram negative bacteria. Results: Carbohydrates were found in concentrations of 582 μg/mL in soluble fraction and 62.1 μg/mL in mucin fraction, and protein concentration of 836 μg/mL in the soluble fraction and 1413 μg/mL in mucin fraction. Antimicrobial activity was demonstrated against the three strains tested. Streptococcus agalactiae reached MIC90 at a concentration of 3.6 μg/mL with mucin fraction; Methicillin-Resistant Staphylococcus aureus had a MIC50 of 3.3 mg / mL and Escherichia coli had a MIC70 of 3.8 mg / mL. Conclusions: This is the first report of the physical and trace elements in the secretion of Achatina fulica. The antibacterial activity obtained against Gram positive and Gram negative strains raises the need for studies to purify the molecules with such activity, understanding the mechanisms of action and establish the safety, among others
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