Despite early promises, Furfural failed to become a major chemical intermediate as it could not compete with cheap and abundant petrochemicals. But recent societal pressures to replace fossil ...resources with renewable ones, combined with recent technology developments may give it a second chance today. This paper presents recent developments in furfural manufacture and valorization that I have been personally involved in. Specifically, it will first discuss advanced furfural manufacture that integrate biomass fractionation with xylose dehydration. Attention will then be devoted to furfural upgrading to aviation fuels and to chemical intermediates such as BDO/THF and FDCA.
Furfural, a bio-based intermediate that has been sleeping for 50 years, may awaken thanks to recent progress made in its manufacture and its valorization to fuels and chemicals. Display omitted
•Integrate Furfural production with fractionation to improve biomass utilization.•Produce Furfural at high yield with biphasic dehydration or extraction/dehydration processes.•Upgrade Furfural to kerosene and diesel for aviation and heavy-duty transport.•Upgrade Furfural to a variety of chemical intermediates.
Karst regions represent 7–12% of the Earth's continental area, and about one quarter of the global population is completely or partially dependent on drinking water from karst aquifers. Climate ...simulations project a strong increase in temperature and a decrease of precipitation in many karst regions in the world over the next decades. Despite this potentially bleak future, few studies specifically quantify the impact of climate change on karst water resources. This review provides an introduction to karst, its evolution, and its particular hydrological processes. We explore different conceptual models of karst systems and how they can be translated into numerical models of varying complexity and therefore varying data requirements and depths of process representation. We discuss limitations of current karst models and show that at the present state, we face a challenge in terms of data availability and information content of the available data. We conclude by providing new research directions to develop and evaluate better prediction models to address the most challenging problems of karst water resources management, including opportunities for data collection and for karst model applications at so far unprecedented scales.
Key Points
We elaborate the importance of karst water resourcesWe provide a detailed overview of karst modeling approachWe present new methods and directions for their improvement
Nerve management during open hernia repair Wijsmuller, A. R.; van Veen, R. N.; Bosch, J. L. ...
British journal of surgery,
01/2007, Letnik:
94, Številka:
1
Journal Article
Abstract
How massive early-type galaxies (ETGs) assembled their mass, on which timescales the star formation quenched, and when their supersolar metallicity has been established are still open and ...debated issues. Thanks to very deep spectroscopic observations carried out at the Large Binocular Telescope, we simultaneously measured stellar age, metallicity, and velocity dispersion for C1-23152, an ETG at redshift
z
= 3.352, corresponding to an epoch when the universe was ∼1.8 Gyr old. The analysis of its spectrum shows that this galaxy, hosting an active galactic nucleus (AGN), formed and assembled ∼2 × 10
11
M
⊙
, shaping its morphology within the ∼600 Myr preceding the observations, since
z
∼ 4.6. The stellar population has a mean mass-weighted age of
Myr, and it is formed between ∼600 and ∼150 Myr before the observed epoch, the latter being the time since quenching. Its high stellar velocity dispersion,
σ
e
= 409 ± 60 km s
−1
, confirms the high mass (
M
dyn
= 2.2 (±0.4) × 10
11
M
⊙
) and the high mass density (
= Σ
1kpc
= 3.2 (±0.7) × 10
10
M
⊙
kpc
−2
), suggesting a fast dissipative process at its origin. The analysis points toward a supersolar metallicity, Z/H = 0.25
, in agreement with the above picture, suggesting a star formation efficiency much higher than the replenishment time. However, subsolar-metallicity values cannot be firmly ruled out by our analysis. Quenching must have been extremely efficient to reduce the star formation to SFR < 6.5
M
⊙
yr
−1
in less than 150 Myr. This could be explained by the presence of the AGN, even if a causal relation cannot be established from the data. C1-23152 has the same stellar and physical properties of the densest ETGs in the local universe of comparable mass, suggesting that they are C1-23152-like galaxies that evolved to
z
= 0 unperturbed.
Survivors of childhood cancer frequently experience cancer-related cognitive dysfunction, commonly months to years after treatment for pediatric brain tumors, acute lymphoblastic leukemia (ALL), or ...tumors involving the head and neck. Risk factors for cancer-related cognitive dysfunction include young age at diagnosis, treatment with cranial irradiation, use of parenteral or intrathecal methotrexate, female sex, and pre-existing comorbidities. Limiting use and reducing doses and volume of cranial irradiation while intensifying chemotherapy have improved survival and reduced the severity of cognitive dysfunction, especially in leukemia. Nonetheless, problems in core functional domains of attention, processing speed, working memory and visual-motor integration continue to compromise quality of life and performance. We review the epidemiology, pathophysiology and assessment of cancer-related cognitive dysfunction, the impact of treatment changes for prevention, and the broad strategies for educational and pharmacological interventions to remediate established cognitive dysfunction following childhood cancer. The increased years of life saved after childhood cancer warrants continued study toward the prevention and remediation of cancer-related cognitive dysfunction, using uniform assessments anchored in functional outcomes.
The EvtGen particle decay simulation package Lange, David J.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2001, Letnik:
462, Številka:
1
Journal Article
Recenzirano
With several new B-physics experiments now taking data, the physics of B-meson decays will be studied in greater detail than previously possible. It is important to have a simulation of the ...underlying physics processes that is able to accurately describe this data. The EvtGen package provides a framework for the implementation of physics processes relevant to decays of B mesons and other resonances. Models of time dependent CP asymmetries in neutral B meson decays, semileptonic form-factor models, and a full decay table for B decays are a few of the implemented features.
We present high‐resolution records for oxygen isotopes of the planktic foraminifer Globigerinoides ruber (δ18Oruber) and bulk sediment inorganic geochemistry for Holocene‐age sediments from the ...southeast Mediterranean. Our δ18Oruber record appears to be dominated by Nile discharge rather than basin‐scale salinity/temperature changes. Nile discharge was enhanced in the early to middle Holocene relative to today. The timing of the long‐term maximum in Nile discharge during the early Holocene corresponds to the timing of maximum intensity of the Indian Ocean‐influenced Southwest Indian summer monsoon (SIM). This coincidence suggests a major influence of an Indian Ocean moisture source on Nile discharge in the early to middle Holocene, while, presently, the Atlantic Ocean is the main moisture source. Nile discharge was highly variable on multicentennial time scale during the early to middle Holocene, being strongly influenced by variable solar activity. This solar‐driven variability is also recorded in contemporaneous SIM records, however, not observed in an Atlantic Ocean‐derived West African summer monsoon record from the Holocene. This supports the hypothesis that the Indian Ocean moisture source predominantly controlled Nile discharge at that time. Solar‐driven variability in Nile discharge also influenced paleoenvironmental conditions in the eastern Mediterranean. Bulk sediment Ba/Al and V/Al, used as indicators for (export) productivity and redox conditions, respectively, varied both in response to solar forcing on multicentennial time scales. We suggest that changes in Nile discharge on these time scales have been concordant with nutrient inputs to, and shallow ventilation of, the eastern Mediterranean.
Key Points
High‐resolution record of Nile discharge from foraminiferal oxygen isotopes
Early‐Holocene Nile dominated by Indian Ocean moisture
Solar cycles in Mediterranean sapropel S1 intensity linked to Nile discharge
Transcription of ribosomal RNA (rRNA) by RNA Polymerase (Pol) I in the nucleolus is necessary for ribosome biogenesis, which is intimately tied to cell growth and proliferation. Perturbation of ...ribosome biogenesis results in tissue specific disorders termed ribosomopathies in association with alterations in nucleolar structure. However, how rRNA transcription and ribosome biogenesis regulate nucleolar structure during normal development and in the pathogenesis of disease remains poorly understood. Here we show that homozygous null mutations in Pol I subunits required for rRNA transcription and ribosome biogenesis lead to preimplantation lethality. Moreover, we discovered that Polr1a.sup.-/-, Polr1b.sup.-/-, Polr1c.sup.-/- and Polr1d.sup.-/- mutants exhibit defects in the structure of their nucleoli, as evidenced by a decrease in number of nucleolar precursor bodies and a concomitant increase in nucleolar volume, which results in a single condensed nucleolus. Pharmacological inhibition of Pol I in preimplantation and midgestation embryos, as well as in hiPSCs, similarly results in a single condensed nucleolus or fragmented nucleoli. We find that when Pol I function and rRNA transcription is inhibited, the viscosity of the granular compartment of the nucleolus increases, which disrupts its phase separation properties, leading to a single condensed nucleolus. However, if a cell progresses through mitosis, the absence of rRNA transcription prevents reassembly of the nucleolus and manifests as fragmented nucleoli. Taken together, our data suggests that Pol I function and rRNA transcription are required for maintaining nucleolar structure and integrity during development and in the pathogenesis of disease.
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