Breeding and Cereal Yield Progress Fischer, R.A; Edmeades, Gregory O
Crop science,
March 2010, Letnik:
50, Številka:
2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
This paper reviews recent progress in wheat (Triticum aestivum L.), rice (Oryza sativa L.), and maize (Zea mays L.) yields resulting from substantial breeding efforts in mostly favorable environments ...and examines its physiological basis. Breeding and improved agronomy lift potential yield (PY), namely yield with the best variety and management in the absence of manageable abiotic and biotic stresses, and PY increase is a key component of progress in farm yield (FY), the other component being closure of the PY to FY gap. Changes in PY and FY are reviewed for several key production regions, namely the United Kingdom and the Yaqui Valley of Mexico for wheat, Japan and Central Luzon in the Philippines for rice, and Iowa and briefly sub-Saharan Africa for maize. The PY growth rates have fallen and are currently generally no more than 1% per annum and usually much less. The trajectory of FY with time often closely parallels PY, but, especially in developing countries, there remain large yield gaps. In at least one instance (maize in Iowa) the gap between PY and FY appears to be closing rapidly. Current genetic progress is linked to increased biomass accumulation, and this will remain the way forward in the future given the limits to increased harvest index (HI). There is evidence that recent progress is related to increased photosynthesis (e.g., greater radiation use efficiency (RUE) at the canopy level and/or maximum photosynthetic rate P(max) at saturating irradiance at the leaf level) before and around anthesis. There is no theoretical reason why this trend cannot continue, especially given the vast genetic resources already found within each crop species. However, it will not be easily or cheaply accomplished, so prospects for higher rates of potential yield growth appear to be limited, notwithstanding new molecular tools and claims to the contrary. Closing the yield gap, therefore, becomes more important. Many factors are involved, but breeding can also help farmers achieve this through, for example, improved host plant resistance.
Defective Metal‐Organic Frameworks Dissegna, Stefano; Epp, Konstantin; Heinz, Werner R. ...
Advanced materials (Weinheim),
September 13, 2018, Letnik:
30, Številka:
37
Journal Article
Recenzirano
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The targeted incorporation of defects into crystalline matter allows for the manipulation of many properties and has led to relevant discoveries for optimized and even novel technological ...applications of materials. It is therefore exciting to see that defects are now recognized to be similarly useful in tailoring properties of metal‐organic frameworks (MOFs). For instance, heterogeneous catalysis crucially depends on the number of active catalytic sites as well as on diffusion limitations. By the incorporation of missing linker and missing node defects into MOFs, both parameters can be accessed, improving the catalytic properties. Furthermore, the creation of defects allows for adding properties such as electronic conductivity, which are inherently absent in the parent MOFs. Herein, progress of the rapidly evolving field of the past two years is overviewed, putting a focus on properties that are altered by the incorporation and even tailoring of defects in MOFs. A brief account is also given on the emerging quantitative understanding of defects and heterogeneity in MOFs based on scale‐bridging computational modeling and simulations.
Defects are recognized to be useful in tailoring the properties of metal–organic frameworks (MOFs). An overview of progress in this rapidly evolving field during the past two years is provided, putting the focus on functions that are altered by the incorporation of defects in MOFs.
To assess the appropriateness of outpatient antibiotic prescribing for privately insured children and non-elderly adults in the US using a comprehensive classification scheme of diagnosis codes in ...ICD-10-CM (international classification of diseases-clinical modification, 10th revision), which replaced ICD-9-CM in the US on 1 October 2015.
Cross sectional study.
MarketScan Commercial Claims and Encounters database, 2016.
19.2 million enrollees aged 0-64 years.
A classification scheme was developed that determined whether each of the 91 738 ICD-10-CM diagnosis codes "always," "sometimes," or "never" justified antibiotics. For each antibiotic prescription fill, this scheme was used to classify all diagnosis codes in claims during a look back period that began three days before antibiotic prescription fills and ended on the day fills occurred. The main outcome was the proportion of fills in each of four mutually exclusive categories: "appropriate" (associated with at least one "always" code during the look back period, "potentially appropriate" (associated with at least one "sometimes" but no "always" codes), "inappropriate" (associated only with "never" codes), and "not associated with a recent diagnosis code" (no codes during the look back period).
The cohort (n=19 203 264) comprised 14 571 944 (75.9%) adult and 9 935 791 (51.7%) female enrollees. Among 15 455 834 outpatient antibiotic prescription fills by the cohort, the most common antibiotics were azithromycin (2 931 242, 19.0%), amoxicillin (2 818 939, 18.2%), and amoxicillin-clavulanate (1 784 921, 11.6%). Among these 15 455 834 fills, 1 973 873 (12.8%) were appropriate, 5 487 003 (35.5%) were potentially appropriate, 3 592 183 (23.2%) were inappropriate, and 4 402 775 (28.5%) were not associated with a recent diagnosis code. Among the 3 592 183 inappropriate fills, 2 541 125 (70.7%) were written in office based settings, 222 804 (6.2%) in urgent care centers, and 168 396 (4.7%) in emergency departments. In 2016, 2 697 918 (14.1%) of the 19 203 264 enrollees filled at least one inappropriate antibiotic prescription, including 490 475 out of 4 631 320 children (10.6%) and 2 207 173 out of 14 571 944 adults (15.2%).
Among all outpatient antibiotic prescription fills by 19 203 264 privately insured US children and non-elderly adults in 2016, 23.2% were inappropriate, 35.5% were potentially appropriate, and 28.5% were not associated with a recent diagnosis code. Approximately 1 in 7 enrollees filled at least one inappropriate antibiotic prescription in 2016. The classification scheme could facilitate future efforts to comprehensively measure outpatient antibiotic appropriateness in the US, and it could be adapted for use in other countries that use ICD-10 codes.
In this work, the covalent attachment of an amine functionalized metal‐organic framework (UiO‐66‐NH2 = Zr6O4(OH)4(bdc‐NH2)6; bdc‐NH2 = 2‐amino‐1,4‐benzenedicarboxylate) (UiO‐Universitetet i Oslo) to ...the basal‐plane of carboxylate functionalized graphene (graphene acid = GA) via amide bonds is reported. The resultant GA@UiO‐66‐NH2 hybrid displayed a large specific surface area, hierarchical pores and an interconnected conductive network. The electrochemical characterizations demonstrated that the hybrid GA@UiO‐66‐NH2 acts as an effective charge storing material with a capacitance of up to 651 F g−1, significantly higher than traditional graphene‐based materials. The results suggest that the amide linkage plays a key role in the formation of a π‐conjugated structure, which facilitates charge transfer and consequently offers good capacitance and cycling stability. Furthermore, to realize the practical feasibility, an asymmetric supercapacitor using a GA@UiO‐66‐NH2 positive electrode with Ti3C2TX MXene as the opposing electrode has been constructed. The cell is able to deliver a power density of up to 16 kW kg−1 and an energy density of up to 73 Wh kg−1, which are comparable to several commercial devices such as Pb‐acid and Ni/MH batteries. Under an intermediate level of loading, the device retained 88% of its initial capacitance after 10 000 cycles.
A facile method for the preparation of graphene/metal–organic framework (MOF) hybrids with an amine‐functionalized MOF and carboxylate‐functionalized graphene via amide bonds for capacitance applications is demonstrated.
Defect-Engineered Metal-Organic Frameworks Fang, Zhenlan; Bueken, Bart; De Vos, Dirk E. ...
Angewandte Chemie (International ed.),
June 15, 2015, Letnik:
54, Številka:
25
Journal Article
Recenzirano
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Defect engineering in metal–organic frameworks (MOFs) is an exciting concept for tailoring material properties, which opens up novel opportunities not only in sorption and catalysis, but also in ...controlling more challenging physical characteristics such as band gap as well as magnetic and electrical/conductive properties. It is challenging to structurally characterize the inherent or intentionally created defects of various types, and there have so far been few efforts to comprehensively discuss these issues. Based on selected reports spanning the last decades, this Review closes that gap by providing both a concise overview of defects in MOFs, or more broadly coordination network compounds (CNCs), including their classification and characterization, together with the (potential) applications of defective CNCs/MOFs. Moreover, we will highlight important aspects of “defect‐engineering” concepts applied for CNCs, also in comparison with relevant solid materials such as zeolites or COFs. Finally, we discuss the future potential of defect‐engineered CNCs.
Designer defects: Defects in coordination network compounds (CNCs) are defined as “sites that locally break the regular periodic arrangement of atoms or ions of the static crystalline parent framework due to missing or incorrectly dislocated atoms or ions”. This Review provides both a concise overview of defects in CNCs (including their classification and characterizations) and applications of defective CNCs/MOFs.
ABSTRACT We present a catalog of uniformly determined stellar properties and abundances for 1,617 F, G, and K stars using an automated spectral synthesis modeling procedure. All stars were observed ...using the HIRES spectrograph at Keck Observatory. Our procedure used a single line list to fit model spectra to observations of all stars to determine effective temperature, surface gravity, metallicity, projected rotational velocity, and the abundances of 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, and Y). Sixty percent of the sample had Hipparcos parallaxes and V-band photometry, which we combined with the spectroscopic results to obtain mass, radius, and luminosity. Additionally, we used the luminosity, effective temperature, metallicity and -element enhancement to interpolate in the Yonsei-Yale isochrones to derive mass, radius, gravity, and age ranges for those stars. Finally, we determined new relations between effective temperature and macroturbulence for dwarfs and subgiants. Our analysis achieved precisions of 25 K in , 0.01 dex in M/H, 0.028 dex for , and 0.5 km s−1 in based on multiple observations of the same stars. The abundance results were similarly precise, between ∼0.01 and ∼0.04 dex, though trends with respect to remained for which we derived empirical corrections. The trends, though small, were much larger than our uncertainties and are shared with published abundances. We show that changing our model atmosphere grid accounts for most of the trend in M/H between 5000 and 5500 K, indicating a possible problem with the atmosphere models or opacities.
Severe influenza infection represents a leading cause of global morbidity and mortality. Although influenza is primarily considered a viral infection that results in pathology limited to the ...respiratory system, clinical reports suggest that influenza infection is frequently associated with a number of clinical syndromes that involve organ systems outside the respiratory tract. A comprehensive MEDLINE literature review of articles pertaining to extra‐pulmonary complications of influenza infection, using organ‐specific search terms, yielded 218 articles including case reports, epidemiologic investigations, and autopsy studies that were reviewed to determine the clinical involvement of other organs. The most frequently described clinical entities were viral myocarditis and viral encephalitis. Recognition of these extra‐pulmonary complications is critical to determining the true burden of influenza infection and initiating organ‐specific supportive care.
Metal–organic frameworks (MOFs) have diverse potential applications in catalysis, gas storage, separation, and drug delivery because of their nanoscale periodicity, permanent porosity, channel ...functionalization, and structural diversity. Despite these promising properties, the inherent structural features of even some of the best‐performing MOFs make them moisture‐sensitive and unstable in aqueous media, limiting their practical usefulness. This problem could be overcome by developing stable hydrophobic MOFs whose chemical composition is tuned to ensure that their metal–ligand bonds persist even in the presence of moisture and water. However, the design and fabrication of such hydrophobic MOFs pose a significant challenge. Reported syntheses of hydrophobic MOFs are critically summarized, highlighting issues relating to their design, characterization, and practical use. First, wetting of hydrophobic materials is introduced and the four main strategies for synthesizing hydrophobic MOFs are discussed. Afterward, critical challenges in quantifying the wettability of these hydrophobic porous surfaces and solutions to these challenges are discussed. Finally, the reported uses of hydrophobic MOFs in practical applications such as hydrocarbon storage/separation and their use in separating oil spills from water are summarized. Finally, the state of the art is summarized and promising future developments of hydrophobic MOFs are highlighted.
Metal–organic frameworks (MOFs) have diverse potential applications in catalysis, gas storage, separation, and drug delivery. Recent progress in synthetic routes, properties, critical challenges of characterization, and applications of hydrophobic metal–organic frameworks are critically summarized.
Superhydrophobic/superoleophilic composites HFGO@ZIF‐8 have been prepared from highly fluorinated graphene oxide (HFGO) and the nanocrystalline zeolite imidazole framework ZIF‐8. The ...structure‐directing and coordination‐modulating properties of HFGO allow for the selective nucleation of ZIF‐8 nanoparticles at the graphene surface oxygen functionalities. This results in localized nucleation and size‐controlled ZIF‐8 nanocrystals intercalated in between HFGO layers. The composite microstructure features fluoride groups bonded at the graphene. Self‐assembly of a unique micro‐mesoporous architecture is achieved, where the micropores originate from ZIF‐8 nanocrystals, while the functionalized mesopores arise from randomly organized HFGO layers separated by ZIF‐8 nanopillars. The hybrid material displays an exceptional high water contact angle of 162° and low oil contact angle of 0° and thus reveals very high sorption selectivity, fast kinetics, and good absorbencies for nonpolar/polar organic solvents and oils from water. Accordingly, Sponge@HFGO@ZIF‐8 composites are successfully utilized for oil–water separation.
Pores for effect: The superhydrophobic and simultaneously superoleophilic HFGO@ZIF‐8 composites were utilized for oil–water separation. In this material zeolitic imidazolate (ZIF) nanocrystals serve as pillars between nanosheets of highly fluorinated graphene oxide.
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