•Mechanisms, effects of variables, and prediction of agglomeration were reviewed.•Two principal mechanisms of agglomeration: coating-induced and melt-induced.•Temperature, fuel, bed material, and ...additives are key for agglomeration control.•An overview of predicative methods is given, with signposting to recent reviews.
A key issue associated with fluidized bed combustion of biomass is agglomeration. The presence of high quantities of alkali metal species in biomass ash leads to the formation of sticky alkali silicate liquid phases during combustion, and consequently the adhesion and agglomeration of bed material. This review examines probable mechanisms of agglomeration and the effects of operational variables in reducing its severity. Additionally, an overview of monitoring and prediction of agglomerate formation is given. Two key mechanisms of agglomeration are apparent in literature, and both may occur concurrently dependending on fuel composition. Coating-induced agglomeration is defined by the interaction of alkali metals in fuel ash with silica in the bed material to form an alkali silicate melt. Melt-induced agglomeration is defined by the presence of sufficient amounts of alkali metals and silica in the fuel ash which together form a eutectic melt. Physical mechanisms, such as tumble agglomeration and sintering, may further enhance either of the coating-induced or melt-induced mechanisms. Of the operational variables examined in this review, temperature, fluidizing gas velocity, fuel, bed material and additives have been shown to have the greatest effect on agglomeration severity. Prediction of agglomeration propensity may be attempted with mathematical correlations or lab-scale fuel testing before use in the boiler, or with in-situ methods, which are typically focused on temperature or pressure analysis. The review of the literature has highlighted the need for further research in several areas, including: mechanisms when using alternate bed materials, use of dual-fuel biomass blends, technical and economic optimisation of the use of alternative bed materials and additives, and further modelling of coating growth behaviours.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Species' functional traits are an important part of the ecological complexity that determines the provisioning of ecosystem services. In biological pest control, predator response to pest density ...variation is a dynamic trait that impacts the provision of this service in agroecosystems. When pest populations fluctuate, farmers relying on biocontrol services need to know how natural enemies respond to these changes. Here we test the effect of variation in coffee berry borer (CBB) density on the biocontrol efficiency of a keystone ant species (Azteca sericeasur) in a coffee agroecosystem. We performed exclosure experiments to measure the infestation rate of CBB released on coffee branches in the presence and absence of ants at four different CBB density levels. We measured infestation rate as the number of CBB bored into fruits after 24 hours, quantified biocontrol efficiency (BCE) as the proportion of infesting CBB removed by ants, and estimated functional response from ant attack rates, measured as the difference in CBB infestation between branches. Infestation rates of CBB on branches with ants were significantly lower (71%-82%) than on those without ants across all density levels. Additionally, biocontrol efficiency was generally high and did not significantly vary across pest density treatments. Furthermore, ant attack rates increased linearly with increasing CBB density, suggesting a Type I functional response. These results demonstrate that ants can provide robust biological control of CBB, despite variation in pest density, and that the response of predators to pest density variation is an important factor in the provision of biocontrol services. Considering how natural enemies respond to changes in pest densities will allow for more accurate biocontrol predictions and better-informed management of this ecosystem service in agroecosystems.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Natural pest control is an alternative to pesticide use in agriculture, and may help to curb insect declines and promote crop production. Nonconsumptive interactions in natural pest control that ...historically have received far less attention than consumptive interactions, may have distinct impacts on pest damage suppression and may also mediate positive multipredator interactions. Additionally, when nonconsumptive effects are driven by natural enemy aggression, variation in alternative resources for enemies may impact the strength of pest control. Here we study control of the coffee berry borer (CBB), Hypothenemus hampei, by a keystone arboreal ant species, Azteca sericeasur, which exhibits a nonconsumptive effect on CBB by throwing them off coffee plants. We conducted two experiments to investigate: (1) if the strength of this behavior is driven by spatial or temporal variability in scale insect density (an alternative resource that Azteca tends for honeydew), (2) if this behavior mediates positive interactions between Azteca and other ground‐foraging ants, and (3) the effect this behavior has on the overall suppression of CBB damage in multipredator scenarios. Our behavioral experiment showed that nearly all interactions between Azteca and CBB are nonconsumptive and that this behavior occurs more frequently in the dry season and with higher densities of scale insects on coffee branches. Our multipredator experiment revealed that borers thrown off coffee plants by Azteca can survive and potentially damage other nearby plants but may be suppressed by ground‐foraging ants. Although we found no non‐additive effects between Azteca and ground‐foraging ants on overall CBB damage, together, both species resulted in the lowest level of plant damage with the subsequent reduction in “spillover” damage caused by thrown CBB, indicating spatial complementarity between predators. These results present a unique case of natural pest control, in which damage suppression is driven almost exclusively by nonconsumptive natural enemy aggression, as opposed to consumption or prey behavioral changes. Furthermore, our results demonstrate the variability that may occur in nonconsumptive pest control interactions when natural enemy aggressive behavior is impacted by alternative resources, and also show how these nonconsumptive effects can mediate positive interactions between natural enemies to enhance overall crop damage reduction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
It is well known that cross-linguistic interactions can exist between the two languages in a bilingual speaker’s repertoire. At the level of phonetics and phonology, this interaction may result in ...the transfer of a feature from one language to the other or the ‘merging’ of phonetic properties between languages. Although there are numerous studies of bilingual speakers which show such interactions, relatively little is known about the nature of transfer in communities of long-term bilingualism. The current study investigates phonological transfer of /r/ in Welsh-English bilinguals’ speech in north Wales. Specifically, it compares the influence of speaker gender, home language, and speech context on the production of /r/ in both English and Welsh in two communities which differ in the extent to which Welsh is spoken as a community language. It is commonly assumed that the alveolar trill r and alveolar tap ɾ are the variants of /r/ in Welsh. In English, the alveolar approximant ɹ is typical across Wales, but the trill and tap are reported in areas where a high proportion of the population speaks Welsh. Data in both languages were collected from 32 Welsh-English bilinguals (aged 16–18) via sociolinguistic interview and wordlist tasks. The sample was stratified equally by speaker gender, home language, and area (predominantly Welsh-speaking vs. predominantly English-speaking). The results show areal differences in the production of /r/ in both languages, which, I argue, could be attributed partly to differing social structures in the communities under investigation. Consequently, the results showed evidence of bi-directional phonological transfer, which is community-specific and influenced by a number of social factors.
Thousand-and-one amino acid kinases (TAOK) 1 and 2 are activated catalytically during mitosis and can contribute to mitotic cell rounding and spindle positioning. Here, we characterize a compound ...that inhibits TAOK1 and TAOK2 activity with IC
values of 11 to 15 nmol/L, is ATP-competitive, and targets these kinases selectively. TAOK inhibition or depletion in centrosome-amplified SKBR3 or BT549 breast cancer cell models increases the mitotic population, the percentages of mitotic cells displaying amplified centrosomes and multipolar spindles, induces cell death, and inhibits cell growth. In contrast, nontumorigenic and dividing bipolar MCF-10A breast cells appear less dependent on TAOK activity and can complete mitosis and proliferate in the presence of the TAOK inhibitor. We demonstrate that TAOK1 and TAOK2 localize to the cytoplasm and centrosomes respectively during mitosis. Live cell imaging shows that the TAOK inhibitor prolongs the duration of mitosis in SKBR3 cells, increases mitotic cell death, and reduces the percentages of cells exiting mitosis, whereas MCF-10A cells continue to divide and proliferate. Over 80% of breast cancer tissues display supernumerary centrosomes, and tumor cells frequently cluster extra centrosomes to avoid multipolar mitoses and associated cell death. Consequently, drugs that stimulate centrosome declustering and induce multipolarity are likely to target dividing centrosome-amplified cancer cells preferentially, while sparing normal bipolar cells. Our results demonstrate that TAOK inhibition can enhance centrosome declustering and mitotic catastrophe in cancer cells, and these proteins may therefore offer novel therapeutic targets suitable for drug inhibition and the potential treatment of breast cancers, where supernumerary centrosomes occur.
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•Laboratory experiments were performed with two ant species that forage on coffee.•Both ant species consumed immature coffee berry borer (CBB) removed from fruits.•Only one ant species readily ...entered CBB galleries in infested coffee fruits.•Smaller ants that predate immature CBB on coffee may help control this major pest.
The coffee berry borer (CBB) is a devastating pest of coffee around the world. One potential control strategy is to conserve habitat for natural enemies of CBB in coffee agroecosystems so they can better suppress populations of this pest. Ants predate adult CBB and reduce infestation levels on coffee plants, but few experiments have tested their ability to consume immature CBB inside of fruits. This could prove an important part of controlling CBB populations since berries house many immature individuals on coffee plants during and between growing seasons. Here we experiment with Wasmannia auropunctata and Solenopsis picea, two species of ants that are commonly found nesting and foraging on coffee plants in southern Mexico. We performed a predation experiment in the laboratory, where ant nests of each species were exposed to CBB larvae and pupae extracted from fruits and removal rate was recorded over time. We also tested the ants’ ability to enter CBB galleries in infested coffee fruit. We found that both ant species removed CBB immature individuals in the laboratory, but that W. auropunctata removed them significantly faster than S. picea. While both species showed increased activity after exposure to infested fruits, only W. auropunctata maintained activity around fruits and readily entered CBB galleries in fruits, despite documenting this behavior with S. picea outside of experimental trials. These results suggest that some ant species, which forage on coffee and are small enough to enter CBB galleries, have potential to contribute to biocontrol by consuming immature CBB inside infested fruits. However, further experiments in the field under realistic conditions will be needed to fully estimate this effect.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Radiologists play a key role in brain tumor diagnosis and management and must stay abreast of developments in the field to advance patient care and communicate with other health care providers. In ...2016, the World Health Organization (WHO) released an update to its brain tumor classification system that included numerous significant changes. Several previously recognized brain tumor diagnoses, such as oligoastrocytoma, primitive neuroectodermal tumor, and gliomatosis cerebri, were redefined or eliminated altogether. Conversely, multiple new entities were recognized, including diffuse leptomeningeal glioneuronal tumor and multinodular and vacuolating tumor of the cerebrum. The glioma category has been significantly reorganized, with several infiltrating gliomas in children and adults now defined by genetic features for the first time. These changes were driven by increased understanding of important genetic factors that directly impact tumorigenesis and influence patient care. The increased emphasis on genetic factors in brain tumor diagnosis has important implications for radiology, as we now have tools that allow us to evaluate some of these alterations directly, such as the identification of 2-hydroxyglutarate within infiltrating gliomas harboring mutations in the genes for the isocitrate dehydrogenases. For other tumors, such as medulloblastoma, imaging can demonstrate characteristic patterns that correlate with particular disease subtypes. The purpose of this article is to review the changes to the WHO brain tumor classification system that are most pertinent to radiologists.
RSNA, 2017.
Specific forms of the lipid ceramide, synthesized by the ceramide synthase enzyme family, are believed to regulate metabolic physiology. Genetic mouse models have established C16 ceramide as a driver ...of insulin resistance in liver and adipose tissue. C18 ceramide, synthesized by ceramide synthase 1 (CerS1), is abundant in skeletal muscle and suggested to promote insulin resistance in humans. We herein describe the first isoform-specific ceramide synthase inhibitor, P053, which inhibits CerS1 with nanomolar potency. Lipidomic profiling shows that P053 is highly selective for CerS1. Daily P053 administration to mice fed a high-fat diet (HFD) increases fatty acid oxidation in skeletal muscle and impedes increases in muscle triglycerides and adiposity, but does not protect against HFD-induced insulin resistance. Our inhibitor therefore allowed us to define a role for CerS1 as an endogenous inhibitor of mitochondrial fatty acid oxidation in muscle and regulator of whole-body adiposity.
More than 95% of genes in the human genome are alternatively spliced to form multiple transcripts, often encoding proteins with differing or opposing function. The control of alternative splicing is ...now being elucidated, and with this comes the opportunity to develop modulators of alternative splicing that can control cellular function. A number of approaches have been taken to develop compounds that can experimentally, and sometimes clinically, affect splicing control, resulting in potential novel therapeutics. Here we develop the concepts that targeting alternative splicing can result in relatively specific pathway inhibitors/activators that result in dampening down of physiologic or pathologic processes, from changes in muscle physiology to altering angiogenesis or pain. The targets and pharmacology of some of the current inhibitors/activators of alternative splicing are demonstrated and future directions discussed.
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