25 research outputs found

    Variation in baobab (Adansonia digitata L.) root tuber development and leaf number among different growth conditions for five provenances in Malawi

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    The baobab tree is an underutilised indigenous fruit tree in sub-Saharan Africa which, at the same time is vulnerable to overexploitation in areas close to centres of demand, as currently baobab use is limited to wild, baobab trees. Baobab seedlings are known to form root tubers, but little is known about their growth characteristics and its yield potential. This study aims to investigate the root tuber and leaf development of baobab seedlings grown from seeds of five provenances, sown at three different planting distances in two nursery trials at climatically distinct locations in Malawi, namely Mzuzu and Mangochi. The observed yield data was fed into preliminary farm-gate profitability analyses for three different scenarios that differed by planting distance. Results indicate increased growth rates for root dry mass and number of developed leaves with increasing planting distance. However, we did not find a significant effect of seedling provenance on any of the measured plant growth parameters. Seedlings invested mainly into root development during the growth period, with root tubers reaching an average fresh weight of 41 ± 39 g and an average length of 24 ± 11.9 cm at 138 days after sowing. Profitability analyses showed a potential total net benefit of 12.78 USD per harvest cycle of 16 weeks and per 100 m² of land cultivated with baobab root tubers, which was better than an alternative scenario of maize cropping on the same area that showed a negative total net benefit when cost of family labour was included. However, the heterogeneity of root tuber development as affected by abiotic and biotic factors like soil fertility and water availability, as well as genetic origin warrant further investigation

    The MASCOT Magnetometer

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    The Mobile Asteroid Scout (MASCOT) is a small lander on board the Hayabusa2 mission of the Japan Aerospace Exploration Agency to the asteroid 162173 Ryugu. Among the instruments on MASCOT is a fluxgate magnetometer, the MASCOT Magnetometer (MasMag). The magnetometer is a lightweight ( ∼280 g∼280 g ) and low power ( ∼0.5 W∼0.5 W ) triaxial fluxgate magnetometer. Magnetic field measurements during the landing period and during the surface operational phase shall provide information about any intrinsic magnetic field of the asteroid and its remanent magnetization. This could provide important constraints on planet formation and the thermal and aqueous evolution of primitive asteroids.Thomas F. PetersonUnited States. National Aeronautics and Space Administration. Emerging Worlds Progra

    Criteria for solid recovered fuels as a substitute for fossil fuels – a review

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    The waste treatment, particularly the thermal treatment of waste has changed fundamentally in the last 20 years, i.e. from facilities solely dedicated to the thermal treatment of waste to facilities, which in addition to that ensure the safe plant operation and fulfill very ambitious criteria regarding emission reduction, resource recovery and energy efficiency as well. Therefore this contributes to the economic use of raw materials and due to the energy recovered from waste also to the energy provision. The development described had the consequence that waste and solid recovered fuels (SRF) has to be evaluated based on fuel criteria as well. Fossil fuels – coal, crude oil, natural gas etc. have been extensively investigated due to their application in plants for energy conversion and also due to their use in the primary industry. Thereby depending on the respective processes, criteria on fuel technical properties can be derived. The methods for engineering analysis of regular fuels (fossil fuels) can be transferred only partially to SRF. For this reason methods are being developed or adapted to current analytical methods for the characterization of SRF. In this paper the possibilities of the energetic utilization of SRF and the characterization of SRF before and during the energetic utilization will be discussed

    Synthesis of carboxyl cellulose sulfates with regioselective sulfation and regiospecific oxidation using cellulose trifluoroacetate as intermediates

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    Synthesis of cellulose sulfates (CSs) and carboxyl cellulose sulfates (COCSs) with regioselectively or regiospecifically distributed functional groups within anhydroglucose units was reported. CS with regioselectively distributed sulfate groups at 2,3-O- or 2,6-O-position were homogeneously synthesized and cellulose trifluoroacetate (CTFA) was used as intermediates. The trifluoroacetyl groups were detected primarily at 6-O-position and their distributions could be altered by changing the amount of trifluoroacetyl anhydride (TFAA). Various sulfating agents were used for further homogeneous sulfation of CTFA. The total degree of sulfation (DSS) and the distribution of sulfate groups within the repeating units were affected by the amount of TFAA, the type and amount of sulfating agents. Subsequent homogenous 4-acetamide-TEMPO or TEMPO-mediated oxidation of CS led to COCS with carboxyl groups regiospecifically distributed at C6 position, which may be interesting structural mimics for natural occurring heparin

    Synthesis and characterization of low sulfoethylated cellulose

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    The synthesis and characterization of sulfoethyl cellulose (SEC) exhibiting low degrees of substitution ascribed to sulfoethyl groups (DSSE) were reported. The effects of reaction temperature, duration, reaction mediums as well as sulfoethylating agents on DSSE were investigated. The total DSSE was determined via elemental analysis and the structure of SEC was elucidated by FT Raman, one- (1D-) and two-dimensional (2D-) NMR spectroscopy. Based on the characterization, SEC with diverse total DSSE up to 0.65 were obtained and the primary hydroxyl groups were found to be preferably substituted. Finally, the feasibility of using FT Raman spectroscopy with the band at 1044, 811 or 747 cm−1 as marker band to determine total DSSE of SEC was presented

    Synthesis of carboxyl cellulose sulfate with various contents of regioselectively introduced sulfate and carboxyl groups

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    Both sulfate and carboxyl groups are found in many glycosaminoglycans exhibiting diverse biological activities, such as heparin. Present study reports on the preparation of cellulose derivatives containing both sulfate and carboxyl groups that were regioselectively introduced into anhydroglucose units (AGU) of cellulose. The products – carboxyl cellulose sulfates (COCS) – with various contents of both functional groups were obtained by two synthesis routes. One way started with sulfation of cellulose yielding cellulose sulfate (CS) and was followed by TEMPO-mediated oxidation of CS. In another way, cellulose at first underwent TEMPO-mediated oxidation yielding carboxyl cellulose (COC). Subsequently, acetosulfation of the COC was carried out. The products were characterized by diverse analysis methods, and the amounts of both functional groups in CS, COC and COCS were determined. Finally, the biological activity of COCS was examined

    N-type Inactivation Features of Kv4.2 Channel Gating

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    We examined whether the N-terminus of Kv4.2 A-type channels (4.2NT) possesses an autoinhibitory N-terminal peptide domain, which, similar to the one of Shaker, mediates inactivation of the open state. We found that chimeric Kv2.1(4.2NT) channels, where the cytoplasmic Kv2.1 N-terminus had been replaced by corresponding Kv4.2 domains, inactivated relatively fast, with a mean time constant of 120 ms as compared to 3.4 s in Kv2.1 wild-type. Notably, Kv2.1(4.2NT) showed features typically observed for Shaker N-type inactivation: fast inactivation of Kv2.1(4.2NT) channels was slowed by intracellular tetraethylammonium and removed by N-terminal truncation (Δ40). Kv2.1(4.2NT) channels reopened during recovery from inactivation, and recovery was accelerated in high external K(+). Moreover, the application of synthetic N-terminal Kv4.2 and ShB peptides to inside-out patches containing slowly inactivating Kv2.1 channels mimicked N-type inactivation. Kv4.2 channels, after fractional inactivation, mediated tail currents with biphasic decay, indicative of passage through the open state during recovery from inactivation. Biphasic tail current kinetics were less prominent in Kv4.2/KChIP2.1 channel complexes and virtually absent in Kv4.2Δ40 channels. N-type inactivation features of Kv4.2 open-state inactivation, which may be suppressed by KChIP association, were also revealed by the finding that application of Kv4.2 N-terminal peptide accelerated the decay kinetics of both Kv4.2Δ40 and Kv4.2/KChIP2.1 patch currents. However, double mutant cycle analysis of N-terminal inactivating and pore domains indicated differences in the energetics and structural determinants between Kv4.2 and Shaker N-type inactivation

    Synergy of Mg<sup>2+</sup> and poly(aspartic acid) in additive-controlled calcium carbonate precipitation

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    © The Royal Society of Chemistry.Additive-controlled precipitation of calcium carbonate is central to various fields of research. Technically, scale formation is an important problem, where polycarboxylates are most commonly employed as inhibitors. Herein, we show that the combination of poly(aspartic acid) with magnesium ions leads to synergistic effects that bring about a dramatic increase in the efficiency towards inhibition of nucleation and growth of nanoscopic CaCO3 precursors. These effects can also be crucial in biomineralization processes, where polycarboxylates and magnesium ions are thought to play important roles

    Prognostic impact of perineural, blood and lymph vessel invasion for esophageal cancer

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    Background: With a median survival of <22 months esophageal cancer is one of the most aggressive tumors, up to 20% of node negative patients develop systemic relapse. Studies investigating the prognostic impact of tumor-micro-invasion in blood (AI) and lymphatic vessels (LVI) as well as perineural invasion (PNI) have shown inconsistent results. The aim of the present study was to investigate the prognostic value of the aforementioned factors in a large homogenously treated cohort of patients with esophageal cancer. Methods: Data from 695 patients with surgically treated esophageal cancer were analyzed. AI, LVI and PNI were determined and data were statistically correlated with clinico-pathological parameters and survival of the patients. Results: Thirteen percent of all specimens showed an AI, 35% a LVI and 5% a PNI. The invasion factors were mostly significantly correlated with the established prognostic parameter, including bone marrow micrometastases. Kaplan-Meier analysis revealed a prognostic impact for LVI in both cancer subtypes, while AI and PNI were significant factors in adenocarcinoma only. In multivariate analysis, none showed statistical significance. However, sub-analysis of completely resected, node negative and non-metastasized patients showed a significant prognostic impact of LVI. Conclusion: The prognostic significance of AI, LVI and PNI seems to be limited compared to the established prognostic parameters of the UICC staging system. In completely resected, node negative and nonmetastasized patients, LVI is an independent prognostic parameter for a worse outcome. Those patients might benfit from additional treatment or more intensive follow up
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