Free radical degradation of hydroxyethyl cellulose

The degradation of hydroxyethyl cellulose (HEC) using sodium persulfate (NaPS) as free radical generator was studied at 60, 70 and 80 °C with different NaPS/HEC ratios. During the degradation reaction samples were withdrawn at regular intervals. The amount of persulfate remaining was analyzed by titration and the evolution of the HEC molecular weight distribution and viscosity was followed using size exclusion chromatography (SEC) and rheology, respectively. The results show how the molecular weight of HEC is decreased by varying the NaPS/HEC ratio, reaction time and temperature. It was found that the NaPS/HEC ratio must be kept low in order to maintain the control of the degradation process, since when the NaPS/HEC ratio was too high the degradation rate of HEC was too fast, and the molecular weight distribution became bimodal. Additionally, the decomposition rate of NaPS was found to be independent of pH in the range between pH 2 and 7.     

The body size of wild boar during the Mesolithic in southern Scandinavia

In order to study the body size of wild boarSus scrofa Linnaeus, 1758 during the Boreal and Atlantic Chronozones in southern Scandinavia, 12 measurements of teeth and bones from 32 Mesolithic sites from Scania (Sweden) and Zealand and Jutland (Denmark) were analysed. The osteometric analysis revealed that the body size of wild boar from Scania did not change during the period. The results indicate that the changes of ecological conditions during the transition from the Boreal to the Atlantic chronozones did not affect wild boar in the same way as red deer and roe deer, which decreased in body size during the period. The tooth size of wild boar from Zealand is smaller than in wild boar from Jutland and Scania during the Late Atlantic Chronozones, which probably is the result of the isolation of the population when Zealand became an island. Calculations of withers height show that wild boar in southern Scandinavia during the Atlantic Chronozones were of similar body size as recent wild boar from eastern Europe.     

Protein content and amino acid spectrum of finger millet [Eleusine coracana (L.) Gaertn.] as influenced by nitrogen and sulphur fertilizers

Summary The effect of N and S fertilizers on yield, protein content and amino acid composition of the tropical cereal finger millet was studied in field and sand culture experiments. In the field the grain yield measured from 2400 to 4100 kg/ha, and the seed crude protein from 7 to 13% with rates of N up to 150 kg/ha. Seed crude protein was high in methionine and cystine, but contained less sulphur amino acids when the seed was high in protein.Supplies in excess failed to increase the lower methionine and cystine contents of the crude protein.Sulphur deficiency drastically reduced the synthesis of sulphur amino acids, concomitantly raising the aspartic acid/asparagine content of the leaves up to 45 per cent of their total N content. An S:N weight ratio of 1:10 in the seeds and 1:15 in the leaves indicates adequate supply of sulphur. The importance of finger millet for human nutrition is considered in relation to increasing substitution with other crops, use of nitrogen fertilizers, and the actual sulphur status of soils in East Africa.Sponsored by the Norwegian Agency for International Development.Sponsored by the Norwegian Agency for International Development.     

Developmental strategies of Koenigia islandica, a high-arctic annual plant

Seed germination, growth and flowering of the arctic-alpine annual Koenigia islandica were studied in controlled environment. Intact (unabraded) seeds germinated poorely at temperatures up to 18°C, with an optimum at 24°C (89% in 10 d). Scarified seeds germinated rapidly, and reached 100% germination in 3 d at 21°C, but no >40% germination occurred at 9 and 12°C, The seeds had no light requirement for germination, nor did fluctuating temperatures improve germination
Dry matter production was optimal at 12°C in both short day (SD) and long day (LD) conditions, but was markedly higher in LD than in SD at identical fluences at all temperatures except 21°C where the plants showed symptoms of severe heat stress. The temperature compensation point for net productivity was estimated to 24°C, and negative carbon balance at higher temperatures might be an important physiological mechanism limiting the distribution of K. islandica in Scandinavia.
Flowering was extremely rapid and independent of daylength, even in a high-arctic population from 79°N, In full summer daylight anthesis was reached 24 d after germination and seeds ripened after 36 d at 15°C, Days to anthesis varied little across the temperature range from 6 to 21°C, giving a linear decrease in the heat-sum requirement for the attainment of flowering with decreasing temperature.
It is concluded that conservative seed germination strategy, tininess and rapid development, low temperature optima for growth and reproduction, and daylength indifference of flowering are important adaptations for success of an annual plant in high-arctic and high-alpine environments, Daylength neutrality has facilitated the wide-latitudinal distribution of K. islandica. including the penetration of the species to the southern hemisphere.     

Application of the fourth universal definition of myocardial infarction in clinical practice

Abstract

Purpose: The Fourth Universal Definition of Myocardial Infarction (MI) has highlighted the different pathophysiological mechanisms that may lead to ischaemic and non-ischaemic myocardial injury and has emphasised that the diagnosis of myocardial infarction requires the presence of acute myocardial ischaemia in the setting of acute myocardial injury. This case based review intends to illustrate basic principles on how to apply this new, revised definition in clinical practice.

Methods and Results: The distinction between different types of MIs (type 1 or type 2) and the delineation of MI from acute non-ischaemic myocardial injury may be challenging in individual patients, which is illustrated by presenting and discussing real-life routine cases.

Conclusions: Type 1?MI is a consequence of coronary plaque rupture or erosion with intracoronary thrombus formation that is usually apparent on coronary angiography. Plausible triggering mechanisms causing myocardial oxygen supply/demand mismatch must be identified for the diagnosis of type 2?MI and its treatment should focus initially on management of the underlying disease attributable to acute myocardial ischaemia.     

Age-specific residual reproductive value and reproductive effort in the Iceland scallop,Chlamys islandica (O.F. Müller)

Summary The possibility for a trade-off between age-specific residual reproductive value (RRV) and reproductive effort (RE) was investigated. Different ways of estimating RE did not affect conclusions which were: a) there is no clear trade-off between RRV and RE until the scallop has reached an age of about 13 years, i.e. after a reproductive life of about eight years; b) the larva of C. islandica is more important as a means of dispersal than as a means of maintaining the parent population.     

Quantitation of gibberellins and indoleacetic acid in Begonia leaves: Relationship with environment, regeneration and flowering

Indole-3-acetic acid (IAA) was purified by high performance liquid chromatography (HPLC) and identified by gas chromatography - mass spectrometry (GC-MS) in leaf extracts of Begonia × cheimantha Everett cv. Nova. The content of IAA and of gibberellins A4, A9, A19 and A20 (GAs) previously identified in this material, were quantified by GC-MS in leaves of Begonia plants grown under different temperature and daylength conditions, using deuterated compounds as internal standards. GA1, which was also identified, was present in too low quantities for reliable quantitation. Rapid and significant decreases (within 2–4 days) occurred in the content of both IAA and GAs when the plants were transferred from conditions which are non-inductive for adventitious bud formation and flowering (24°C/long day) to inductive conditions (24°C/short day, 15°C/long day or 15°C/short day). GA4 and GA9 were affected by photoperiod only, whereas IAA, GA19 and GA20 were affected by both photoperiod and temperature. The data suggest that biosynthesis of GA9 and GA4 are blocked in short days at a step located before GA9. Conversion of GA19 to GA20 seemed to be blocked by both short days and low temperature, while an additional block located before GA19 seemed to be imposed in 15°C/short day. The results confirm earlier results and support the hypothesis that photoperiod and temperature effects in Begonia are mediated by endogenous hormones.