389 research outputs found

    Photosynthesis of crop plants as influenced by light, carbon dioxide, temperature, and stomatal diffusion resistance

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    The effect was estimated of light intensity, leaf temperature, and C0 2 concentration on photosynthetic rate in leaves of crop plants. The potential capacities of photochemical and biochemical processes and of C0 2 transport were compared.Resistance to C0 2 transport in various parts of the pathway from external air to reaction centre in the chloroplasts was estimated in absolute units. This allowed quantitative comparison of micrometeorological and physiological effects on photosynthesis.C0 2 transport towards the leaf is affected by the sum of resistances in external air (r a ), stomata (r s ), and mesophyll cells (r m ). Since r m is usually larger than r s of open stomata, r m is probably an important yield determining factor.With adequate water-supply, transpiration depends on r s + r a , but not on r m . Therefore higher values of r s and lower values of r m favour the water balance of crops.With strong light and leaf temperature around 22°C, C0 2 saturation of photosynthesis was reached with C0 2 concentrations between 01 and 0.15 %.Techniques were described for accurate measurement of C0 2 and water vapour, leaf temperature, light intensity and diffusion resistance. The importance of different types of light bulbs for photosynthesis was evaluated, and much attention was paid to accurate assessment of effective C0 2 concentration in the air around leaves in assimilation chambers

    Влияние механической активации гидрида титана на его взаимодействие с азотом и кислородом

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    Показано, что размол гидрида титана в планетарной мельнице приводит к повышению удельной поверхности порошка, росту микроискажений кристаллической решетки, уменьшению содержания в нем водорода и повышению химической активности, что позволяет получать нитрид титана из него в среде азота уже при температуре 500 °С. За счет кислорода, адсорбирован ного механически активированным порошком при нагревании в атмосфере азота, происходят реакции окисления атомов титана, в результате чего образуется низший оксид Tі2О.Показано, що подрібнення гідриду титану в планетарному млині приводить до підвищення питомої поверхні порошку, зростанню дефектів кристалічної ґратки, зменшенню вмісту в ній водню і підвищенню хімічної активності. Це дає змогу досягти повного перетворення механічно активованого гідриду в нітрид титану вже за температури 500 °С і витримці упродовж однієї години в середовищі азоту. За рахунок кисню, адсорбованого механічно активованим порошком при нагрівання в атмосфері азоту, проходять реакції окиснення, в результаті чого утворюється нижчий оксид Ti2O.Milling of titanium hydride in planetary mill is shoun to increase the speci surface area of powder, to decrease the hydrogen content in it and to intensity chemical activity. This makesit possible to obtain titanium nitride from the titanium hydride in a nitrogen atmosphere at as low temperature as 500 °C . Thanks to the presence of oxygen adsorbed by mechanically activated powder under heating in a nitrogen atmosphere? Reaction of intramolecular oxidation -reduction, of titanium takes place, which results in forming the lower oxide Ti2O

    Haemoglobin causes neuronal damage in vivo which is preventable by haptoglobin

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    After subarachnoid haemorrhage, prolonged exposure to toxic extracellular haemoglobin occurs in the brain. Here, we investigate the role of haemoglobin neurotoxicity in vivo and its prevention. In humans after subarachnoid haemorrhage, haemoglobin in cerebrospinal fluid was associated with neurofilament light chain, a marker of neuronal damage. Most haemoglobin was not complexed with haptoglobin, an endogenous haemoglobin scavenger present at very low concentration in the brain. Exogenously added haptoglobin bound most uncomplexed haemoglobin, in the first 2 weeks after human subarachnoid haemorrhage, indicating a wide therapeutic window. In mice, the behavioural, vascular, cellular and molecular changes seen after human subarachnoid haemorrhage were recapitulated by modelling a single aspect of subarachnoid haemorrhage: prolonged intrathecal exposure to haemoglobin. Haemoglobin-induced behavioural deficits and astrocytic, microglial and synaptic changes were attenuated by haptoglobin. Haptoglobin treatment did not attenuate large-vessel vasospasm, yet improved clinical outcome by restricting diffusion of haemoglobin into the parenchyma and reducing small-vessel vasospasm. In summary, haemoglobin toxicity is of clinical importance and preventable by haptoglobin, independent of large-vessel vasospasm

    Genome-Wide Association Study of Clinical Outcome After Aneurysmal Subarachnoid Haemorrhage: Protocol

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    Aneurysmal subarachnoid haemorrhage (aSAH) results in persistent clinical deficits which prevent survivors from returning to normal daily functioning. Only a small fraction of the variation in clinical outcome following aSAH is explained by known clinical, demographic and imaging variables; meaning additional unknown factors must play a key role in clinical outcome. There is a growing body of evidence that genetic variation is important in determining outcome following aSAH. Understanding genetic determinants of outcome will help to improve prognostic modelling, stratify patients in clinical trials and target novel strategies to treat this devastating disease. This protocol details a two-stage genome-wide association study to identify susceptibility loci for clinical outcome after aSAH using individual patient-level data from multiple international cohorts. Clinical outcome will be assessed using the modified Rankin Scale or Glasgow Outcome Scale at 1-24 months. The stage 1 discovery will involve meta-analysis of individual-level genotypes from different cohorts, controlling for key covariates. Based on statistical significance, supplemented by biological relevance, top single nucleotide polymorphisms will be selected for replication at stage 2. The study has national and local ethical approval. The results of this study will be rapidly communicated to clinicians, researchers and patients through open-access publication(s), presentation(s) at international conferences and via our patient and public network

    Real-Time PCR-Based Mismatch Amplification Mutation Assay for Specific Detection of CS6-Expressing Allelic Variants of Enterotoxigenic Escherichia coli and Its Application in Assessing Diarrheal Cases and Asymptomatic Controls

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    Enterotoxigenic Escherichia coli (ETEC) expressing the colonization factor CS6 is widespread in many developing countries, including India. The different allelic variants of CS6, caused by point mutations in its structural genes, cssA and cssB, are designated AIBI, AIIBII, AIIIBI, AIBII, and AIIIBII. A simple, reliable, and specific mismatch amplification mutation assay based on real-time quantitative PCR (MAMA-qPCR) was developed for the first time for the detection of CS6-expressing ETEC, along with the identification of allelic variations. The assay was based on mismatched nucleotide incorporation at the penultimate base at the 3' ends of the reverse primers specific for cssA and cssB and was validated using 38 CS6-expressing ETEC isolates. This strategy was effective in detecting all the alleles containing single-nucleotide polymorphisms. Using MAMA-qPCR, we also tested CS6 allelic variants in 145 ETEC isolates from children with acute diarrhea and asymptomatic infections, with the latter serving as controls. We observed that the AIBI and AIIIBI allelic variants were mostly associated with cases rather than controls, whereas the AIIBII variants were detected mostly in controls. In addition, the AIBI and AIIIBI alleles were frequently associated with ETEC harboring the heat-stable toxin gene (est) alone or with the heat-labile toxin gene (elt), whereas the AIIBII allele was predominant in ETEC isolates harboring the elt gene. This study may help in understanding the association of allelic variants in CS6-expressing ETEC with the clinical features of diarrhea, as well as in ETEC vaccine studies

    Private trade and monopoly structures : the East India Companies and the commodity trade to Europe in the eighteenth century

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    Our research is about the trade in material goods from Asia to Europe over this period, and its impact on Europe’s consumer and industrial cultures. It entails a comparative study of Europe’s East India Companies and the private trade from Asia over the period. The commodities trade was heavily dependent on private trade. The historiography to date has left a blind spot in this area, concentrating instead on corruption and malfeasance. Taking a global history approach we investigate the trade in specific consumer goods in many qualities and varieties that linked merchant communities and stimulated information flows. We set out how private trade functioned alongside and in connection with the various European East India companies; we investigate how this changed over time, how it drew on the Company infrastructure, and how it took the risks and developed new and niche markets for specific Asian commodities that the Companies could not sustain

    Groen proceswater: zuivering brouwerijprocesafvalwater met microalgen : Resultaten onderzoek 2013

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    Afgelopen jaar is de pilot met het kweken van algen met afvalwater van de brouwerijlocatie Zoeterwoude geslaagd. Dit is gedaan in een samenwerkingsverband van Heineken Nederland BV, Algae Food & Fuel en WUR-Acrres. Dit is de eerste inline pilot in de wereld waarbij met LED verlichting op 1000 L schaal algen zijn gekweekt met brouwerijafvalwater als nutriëntenbron. De algenreactoren blijven groen, verbeteren de waterkwaliteit en verwijderen 99% van de opgeloste minerale stikstof (NH4). Hiermee is het eerste doel bereikt, namelijk een aantal weken de algenreactoren on site en inline met de afvalwaterzuivering mee te laten draaien, met een (vooral voor stikstof) goed verwijderingsrendement

    Analysis of stomatal and convective resistances to transpirational flow

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47839/1/484_2005_Article_BF01554062.pd
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