Huanglongbing (HLB) presumably caused by Candidatus Liberibacter asiaticus (C Las) threatens the commercial U.S. citrus crop of an annual value of $3 billion. The earliest shift in metabolite ...profiles of leaves from greenhouse-grown sweet orange trees infected with C las, and of healthy leaves, was characterized by HPLC-MS concurrently with PCR testing for the presence of C las bacteria and observation of disease symptoms. Twenty, 8-month-old ‘Valencia’ and ‘Hamlin’ trees were grafted with budwood from PCR-positive HLB source trees. Five graft-inoculated trees of each variety and three control trees were sampled biweekly and analyzed by HPLC-MS and PCR. Thirteen weeks after inoculation, C las was detected in newly growing flushes in 33% and 55% of the inoculated ‘Hamlin’ and ‘Valencia’ trees, respectively. Inoculated trees remained asymptomatic in the first 20 weeks, but developed symptoms 30 weeks after grafting. No significant differences in the leaf metabolite profiles were detected in C las-infected trees 23 weeks after inoculation. However, 27 weeks after inoculation, differences in metabolite profiles between control leaves and those of C las-infected trees were evident. Affected compounds were identified with authentic standards or structurally classified by their UV and mass spectra. Included among these compounds are flavonoid glycosides, polymethoxylated flavones, and hydroxycinnamates. Four structurally related hydroxycinnamate compounds increased more than 10-fold in leaves from ‘Hamlin’ and ‘Valencia’ sweet orange trees in response to C las infection. Possible roles of these hydroxycinnamates as plant defense compounds against the C las infection are discussed.
A rotor design of a Ram Air Turbine (RAT) for a commercial aircraft was created taking three sections with different airfoils along the blade; those sections were assessed to evaluate their ...performance at different critical velocities (41, 81 and 251 m/s) and choose the best profile configuration generating a new proposal to increase the glide ratio by reducing the drag, which is helpful in emergency cases. The Blade Element Momentum (BEM) theory and Computational Fluid Dynamics (CFD) were used to analyze an initial design, then validating these results with the open software QBlade. For the BEM theory a program was created for the design and performance of the RAT adding the Viterna methodology for airfoil analysis. 16 designs were proposed by strategically interchanging wing profiles in different blade sections. These designs were analyzed by CFD, using the complete rotor and the SSTk−ω turbulence model. An optimal geometry was found, presenting a significant drag reduction of 25% generating an increase in the glide ratio and improving aircraft control in addition to maintaining the power generation above the desired values; therefore, it recommends using different airfoils for each section of a RAT's rotor blade.
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The Pd loading of Pd/MnO2 electrocatalysts was studied to evaluate the performance and the mechanism for the oxygen reduction reaction (ORR) and the hydrogen oxidation reaction (HOR) ...in aqueous electrolyte, as a model of cathodic and the anodic reactions that take place in anionic exchange membrane fuel cells (AEMFC). Regarding the ORR, it was stated that the pure MnO2 nanorods showed catalytic activity towards it. However, the increase in Pd loading enhanced the catalytic kinetic parameter such as Eonset, E1/2, Jlim, and k. Moreover, the Koutecky-Levich analysis exhibited that the ORR process takes place via 4 electrons transferred. Conversely, pure MnO2 nanorods do not show catalytic activity towards HOR; Pd/MnO2 from to 1%Pd loading exhibited catalytic activity, the kinetic parameters were enhanced as Pd loading increases. In both cases, the rate-determining step (RDS) of the ORR and HOR evolved according to the Pd loading. Based on the findings of this research we can establish that Pd/MnO2 catalysts are an excellent option in the catalysis of the ORR and HOR, exhibiting potential application in AEMFC.
Most of information regarding the construction of continuous cooling transformation (CCT) diagrams considers the decomposition of austenite above the critical transformation temperature Ac3. The ...development of new grades of multiphase advanced high-strength steels (AHSS) usually involves an intercritical annealing stage, making it necessary the construction of CCT diagrams from the intercritical range. The availability of CCT diagrams constructed from the intercritical austenite is practically non-existent in the open literature. The present research reports an approach for the design of AHSS based on the behavior of CCT diagrams calculated from the intercritical temperature range as a function of chemical composition. Changes in chemical composition were conducted to promote the fabrication of multiphase AHSS steels under conditions that simulate continuous annealing and galvanizing lines (CAGL). To validate the results obtained from computer simulations, the steel was then fabricated, processed at laboratory scale and subjected to thermal cycles that simulate CAGL. Although there is a good approximation between theoretical and experimental results, it was observed that the software presents some limitations regarding the effects of plastic deformation and carbon partitioning during the isothermal bainitic treatment (IBT) on the final microstructures.
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Wet chemical synthesis of hydroxyapatite (HAp) nanostructures was carried out with different solution pH values (9, 10 and 11) and sintering temperatures (300°C, 500°C, 700°C and 900°C). The effects ...of pH and sintering temperature on the structural and morphological properties of nanocrystalline HAp powders were presented. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to obtain the crystalline structure, chemical composition, morphology and particle size of the HAp powders. The TEM analysis is used in order to observe the rod- and flake-like HAp structures. XRD confirms the presence of both HAp hexagonal and monetite phases, although the monetite phase was less abundant in the resultant powders. Increase in pH reduced the monetite phase and enhanced Ca/P ratio from 1.7 to 1.83. Additionally, an increment in sintering temperature increased the crystallite size from 20 to 56 nm. The SEM analysis revealed the formation of semi-spherical and flake-like HAp structures with preferential flake morphology. An increase in pH and sintering temperature resulted in the growth and coalescence of crystals resulting in a porous capsular morphology. The FTIR analysis confirmed the reduction of carbonate stretching modes with an increase in pH and H–O–H antisymmetric stretching mode is eliminated for powders sintered at 900°C confirming the formation of stable and porous HAp powders.
The variation in seagrass morphology and the magnitude of leaf self-shading within the canopy of Thalassia testudinum, were compared among nine sites in a fringing reef lagoon. We found a significant ...variation in the growth-form of T. testudinum reflected in a 5.4-fold variation in the attenuation coefficient ($K_{\text{d}}$) within the canopy. The largest morphological variation was observed in shoot density. Leaf biomass, leaf area index (LAI), and shoot density were positively associated with canopy-$K_{\text{d}}$and with the percentage of surface irradiance received by the top of the seagrass canopy (% Es). These results provide an explanation for the consistent pattern of depth reduction in seagrass leaf biomass and shoot density reported in the literature. Shoot density and shoot size are two descriptors of the growth-form of T. testudinum related to its clonal life-form. Shoot size was not significantly correlated with canopy-$K_{\text{d}}$, nevertheless, it showed a significant effect on the slope of the relationship between shoot density and canopy-$K_{\text{d}}$. According to this model, shoot size also contributes to light attenuation within the seagrass canopy by increasing the effect of shoot density. This form-function analysis suggests that light may have a relevant role in the regulation of the optimal plant balance between horizontal (variation in shoot density) and vertical (variation in shoot size) growth of seagrasses. Other environmental factors and interactions also need to be examined to fully understand the mechanistic bases of the morphological responses of seagrasses to the environment.
The crystallographic, optical, and electrical properties of manganese sulfide thin films depend on the control of the temperature precursors in the synthesis process, as shown by the results of this ...work. MnS thin films were deposited on glass substrates using the SILAR method and over an additional layer of CdS synthesized by chemical bath deposition (CBD) to acquire a p-n heterojunction. SILAR is an inexpensive method performed with a homemade robot in this case. Temperature in the solution precursors varied from 20 to 80 °C in four experiments. The morphology and structure of MnS and FTO/CdS/MnS thin films were studied through scanning electron microscopy (SEM) and grazing-incidence X-ray diffraction (GIXRD); the results indicate that materials showed a polycrystalline behavior, a diffraction peak of α- MnS cubic phase was observed with lattice constants values, ranging from 4.74 to 4.75 Å.
Additionally, Raman spectroscopy showed a signal corresponding to the transversal optical phonons of MnS at a wavenumber near 300 cm−1. UV–vis spectroscopy showed optical bandgap values of 3.94, 4.0, 4.09, and 4.26 eV for thin films obtained at 20°, 40°, 60°, and 80 °C.
respectively. Results indicated 80 °C as an optimal cationic precursor process temperature, achieving optical transmittance T% and good film quality according to SEM and GIXRD for the synthetization of MnS. The current–voltage (I–V) characterization in the heterojunction showed a characteristic diode curve with an open circuit voltage (VOC) of 300 mV under illumination, which indicated that the manganese sulfide behaves as p-type material contributing with positive charge carriers, while CdS behaves as n-type material.
Gastrointestinal cancers represent one of the most prevalent diseases worldwide. Strikingly, the incidence of Early Onset Gastrointestinal Cancer (EOGIC) has been rising during the last decades and ...changes in lifestyle and environmental exposure seem to play a role. EOGIC has been defined as a different entity compared to on-average gastrointestinal cancer, with distinct clinical and molecular characteristics. Inherent to the particularities of younger age, there is an unmet need for a tailored approach for the management of these patients. The TEOGIC proposes a comprehensive study to characterize EOGIC patients in the northern of Spain.
Patients with histologically confirmed new diagnosis of colorectal, gastroesophageal and pancreatic adenocarcinoma will be considered for two cohorts: EOGIC (≤ 50 years old) and non-EOGIC (60-75 years old), with a ratio of 1:2. Two hundred and forty patients will be recruited in 4 Public Hospitals from northern Spain. After receiving unified informed consent, demographic and clinical data of the patients will be collected in a REDCap database. Lifestyle related data will be obtained in questionnaires assessing diet, physical activity and the general quality of life of the patients before diagnosis. Biological samples prior to any onco-specific treatment will be obtained for the analyses of circulating inflammatory proteins, gut microbiota, and the proteome of the tumor microenvironment. Histologic characteristics and routine biomarkers will be also collected. Thereafter, data will be integrated and analyzed to assess tumor specific, pan-tumor and sex-associated differential characteristics of EOGIC.
The underlying risk factors and differential characteristics of EOGIC remain poorly studied, particularly in our geographical area. Although limited by the exploratory nature and the small sample size estimated to be recruited, TEOGIC represents the first attempt to comprehensively characterize these young patients, and thus attend to their special needs. Findings derived from this study could contribute to raise awareness and preventive behaviors in the population. In parallel, molecular studies could lead to the identification of potential novel non-invasive biomarkers and therapeutic targets that would help in the development of the tailored clinical management of these patients, focusing on screening programs for early diagnosis and precision medicine.
The abandoned “Monte-Fresco” rock phosphate mine in Táchira, Venezuela, was sampled to study the biodiversity of phosphate-solubilizing microorganisms (PSM). Rhizosphere and bulk soils were sampled ...from colonizer plant species growing at a mined site where pH and soluble P were higher than the values found at a near by unmined and shrubby soil. Counting and isolating of PSM choosing strains showing high solubilization halos in a solid minimal medium with hydroxyapatite as phosphate source were evaluated using ammonia or nitrate as nitrogen sources and dextrose, sucrose, and mannitol as carbohydrate sources. A larger number of PSM were found in the rhizospheric than in the bulk soil. Six fungal strains belonging to the genus Penicillium and with high hydroxyapatite dissolution capacities were isolated from bulk soil of colonizer plants. Five of these strains had similar phenotypes to Penicillium rugulosum IR-94MF1 but they solubilized hydroxyapatite at different degrees with both nitrogen sources. From 15 strains of Gram-negative bacteria isolated from the rhizosphere of colonizer plants, 5 were identified as diazotrophic free-living encapsulated Azotobacter species able to use ammonium and/or nitrate to dissolve hydroxyapatite with glucose, sucrose and/or mannitol. Different nitrogen and carbohydrate sources are parameters to be considered to further characterize the diversity of PSM.
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