Yield Of Varieties Research Articles

The synthesis of pyrrolo[2,3- c][1,2,6]thiadiazine-5-carbonitriles from (4 H-1,2,6-thiadiazin-4-ylidene)malononitriles

[3,5-Bis(dialkylamino)-4 H-1,2,6-thiadiazin-4-ylidene]propanedinitriles 6a– c, react with sodium methoxide or ethoxide to give the corresponding 6-alkoxy-4-dialkylamino substituted pyrrolo[2,3- c][1,2,6]thiadiazine-5-carbonitriles 7a– f in variable yields. These new compounds are fully characterised and two rational mechanisms are proposed for their formation.

Ecological footprint analysis of food consumption of rural residents in China in the latest 30 years

Abstract Food consumption appropriates not only arable land but grassland and other various agricultural land resources. It is of great use to analyse time series of ecological appropriation for food consumption of Chinese rural residents from the perspective of total agricultural land resources and then overall evaluation of resource basis to ensure food security with structure upgrading of food consumption. Firstly the appropriated land categories and domestic conversion factors of food consumption items were discussed. Accordingly, the ecological footprint (EF) model with refined factors was applied to macro-estimate the ecological pressure of food consumption and the changes of Chinese rural residents in the latest 30 years. The study indicated that ecological appropriation increased from 1.465 national standard acre (nsa) in 1980 to 1.782 nsa in 2006 with the changes of Chinese food consumption structure of rural residents, and especially the direct appropriated arable land has declined dramatically since 2000. The consumption category of grain was the largest category per capita in spite of decreasing percentage, so staple foods like grain products, vegetables were always laid the first place even though the consumption pattern has changed greatly. Food EF had a strong correlation with expenditure on food over the period; furthermore, it can be evidently proved by an elasticity of per capita meat and aquatic products EF 0.43. The overall ecological pressure of food EF of Chinese rural residents has increased unsteadily, as the grain-consuming animal products and aquatic product contributed to this. The comparison of dynamic analysis of food EF calculated by fixed yields and variable yields indicated that higher productivity of arable land has greatly alleviated the pressure on resources demanded by the process of structure upgrading of the food consumption of rural residents in China.

Synthesis and phytotoxic activity of new pyridones derived from 4-hydroxy-6-methylpyridin-2(1H)-one.

Commercial dehydroacetic acid was converted into 4-hydroxy-6-methylpyridin-2(1H)-one (3), which was then condensed with several aliphatic aldehydes to produce seven new title compounds in variable yields (35–92%). Reaction of 3 with α,β-unsaturated aldehydes resulted in the formation of condensed pyran derivatives 4g’ and 4h’. A mechanism is proposed to explain the formation of such compounds. The effects of all methylpyridin-2(1H)-one derivatives on the development of the dicotyledonous species Ipomoea grandifolia and Cucumis sativus and the monocotyledonous species Sorghum bicolor were evaluated. At the dose of 6.7 × 10-8 mol a.i./g substrate the compounds showed some phytotoxic selectivity, being more active against the dicotyledonous species. These compounds can be used as lead structures for the development of more active phytotoxic products.

Synthesis and Biological Evaluation of New Ozonides with Improved Plant Growth Regulatory Activity

The iron oxyallyl carbocation generated from 2,7-dibromocycloheptanone was induced to undergo [4 + 3] cycloaddition reactions with various furans, affording a series of 12-oxatricyclo-[4.4.1.1(2,5)]-dodec-3-en-11-one adducts. Similar methodology was used to prepare two additional cycloadducts using menthofuran and two homologous aliphatic dibromoketones. Dipolar cycloaddition of ozone to the adducts afforded the corresponding secondary ozonides (i.e., 1,2,4-trioxolanes) in variable yields. Ozonides were investigated by quantum mechanics at the B3LYP/6-31+G* level to study structural features including close contacts which may be responsible for enhancing ozonide stability. The effect of these ozonides and their corresponding precursor cycloadducts upon radicle growth of both Sorghum bicolor and Cucumis sativus was evaluated at 5.0 x 10(-4) mol L(-1). The most active cycloadducts and ozonides were also evaluated against the weed species Ipomoea grandifolia and Brachiaria decumbens, and the results are discussed. Compared to ozonides previously synthesized in our laboratory, the new ozonides described herein present improved plant growth regulatory activity.

Yield estimation and sowing date optimization based on seasonal climate information in the three CLARIS sites

The present article is a contribution to the CLARIS WorkPackage “Climate and Agriculture”, and aims at testing whether it is possible to predict yields and optimal sowing dates using seasonal climate information at three sites (Pergamino, Marcos Juarez and Anguil) which are representative of different climate and soil conditions in Argentina. Considering that we focus on the use of climate information only, and that official long time yield series are not always reliable and often influenced by both climate and technology changes, we decided to build a dataset with yields simulated by the DSSAT (Decision Support System for Agrotechnology Transfer) crop model, already calibrated in the selected three sites and for the two crops of interest (maize and soybean). We simulated yields for three different sowing dates for each crop in each of the three sites. Also considering that seasonal forecasts have a higher skill when using the 3-month average precipitation and temperature forecasts, and that regional climate change scenarios present less uncertainty at similar temporal scales, we decided to focus our analysis on the use of quarterly precipitation and temperature averages, measured at the three sites during the crop cycle. This type of information is used as input (predictand) for non-linear statistical methods (Multivariate Adaptive Regression Splines, MARS; and classification trees) in order to predict yields and their dependency to the chosen sowing date. MARS models show that the most valuable information to predict yield amplitude is the 3-month average precipitation around flowering. Classification trees are used to estimate whether climate information can be used to infer an optimal sowing date in order to optimize yields. In order to simplify the problem, we set a default sowing date (the most representative for the crop and the site) and compare the yield amplitudes between such a default date and possible alternative dates sometimes used by farmers. Above normal average temperatures at the beginning and the end of the crop cycle lead to respectively later and earlier optimal sowing. Using this classification, yields can be potentially improved by changing sowing date for maize but it is more limited for soybean. More generally, the sites and crops which have more variable yields are also the ones for which the proposed methodology is the most efficient. However, a full evaluation of the accuracy of seasonal forecasts should be the next step before confirming the reliability of this methodology under real conditions.

Factors influencing prenylation of an aromatic organolithium

An apparently routine metal–halogen exchange (MHE) reaction gave variable low yields under typical conditions. 13C and 7Li NMR studies suggested a diversity of organolithiums were formed in the MHE reaction leading to a plethora of products on subsequent electrophilic aromatic substitution with geranyl bromide. A reversal of reagent addition simplified the 7Li NMR spectrum and the product distribution, in addition to increasing the isolated yield of the desired product from a variable 5-40% to a consistent 65%.

Catalytic Epoxidation and Sulfoxidation Activity of a Dioxomolybdenum(VI) Complex Bearing a Chiral Tetradentate Oxazoline Ligand

A dioxomolybdenum(vi) complex bearing a tetradentate anionic N,O oxazoline ligand with four stereocenters has been studied as a catalyst in the liquid-phase epoxidation of 17 different aliphatic and aromatic olefins (including prochiral, racemate or pure enantiomers) using tert-butyl hydroperoxide as the oxidant. Epoxide selectivities of up to 100% and variable epoxide yields (3–100% within 24 h) were obtained. Although the complex generally exhibited low or no chiral induction ability, diastereoselectivity was significant in some cases (in the reaction of limonene, for example). Kinetic studies and recycling tests with the substrates cis-cyclooctene and trans-β-methylstyrene showed that the catalyst is stable and reusable, and recycling is facilitated by immobilization of the complex in a room temperature ionic liquid. Preliminary results show that the complex may have a broad substrate scope, not only for olefin epoxidation, but also for the dehydrogenation of alcohols to carbonyl compounds and the sulfoxidation of sulfides to sulfoxides.

Synthesis and in vitro anti Mycobacterium tuberculosis activity of a series of phthalimide derivatives

New phthalimide derivatives were easily prepared through condensation of phthalic anhydride and selected amines with variable yields (70–90%). All compounds ( 3a– l) were evaluated against Mycobacterium tuberculosis H 37Rv using Alamar Blue susceptibility. The compounds 3c, 3i, and 3l have the minimum inhibitory concentrations (MICs) of 3.9, 7.8, and 5.0 μg/mL, respectively, and could be considered new lead compounds in the treatment of tuberculosis and multi-drug resistant tuberculosis.

Reduction screening with endophytic fungi: Synthesis of homochiral secondary alcohols

Twelve strains of endophytic fungi, isolated from various plants (i.e. Eugenia hallii, Schinus molle, Crataegus monogyna, Juniperus communis and Sambucus nigra) sampled in Amazonian forest and in Italy, were screened for their reduction activity with a cocktail of ketones 1–4. The four most active strains [i.e. Phomopsis (FE86 and FE290), Pestalotia and Epicoccum] were chosen for the reduction of 5-hexen-2-one 1, acetophenone 2, cis-bicyclo[3.2.0]hept-2-en-6-one 3, 2-methylcyclohexanone 4, 6-methyl-5-hepten-2-one 5, 2-furyl methyl ketone 6, 1-indanone 7, and 2,4,4-trimethyl-2-cyclohexen-1-one 8 and in all cases the S-alcohols were obtained with variable yields and enantiomeric excesses depending on the strains.

Neurotrophism of Bone Marrow Stromal Cells to Embryonic Stem Cells: Noncontact Induction and Transplantation to a Mouse Ischemic Stroke Model

Embryonic stem (ES) cell-derived cell products may serve as a source of cells for regenerative medicine. Currently available technologies for the induction of ES cells into neural lineage cells require extended culturing in vitro and complex procedural manipulations, with variable yields of heterogeneous cells, which have hindered the prospective use of cell derivatives for treatment of ischemic stroke. We established a simple and efficient method to derive mouse ES cells into neural lineage cells using an 8-day coculture with the bone marrow stromal cells MS5, followed by a 6-day propagation culture and a 4-day selection culture. The protocol generated a relatively high yield of neural lineage cells without any mesodermal and endodermal lineage commitment. In in vivo study, these derived cells could improve the cognitive function of ischemic stroke mice. Three weeks after transplantation, migration of implanted cells to lesioned areas was noted. It was also evident of a normalization of pyramidal neuron density and morphology in hippocampal CA1 region. One (1/17) episode of teratoma development was noted. Data suggested that MS5 cells may exert a neurotrophic effect to enhance neural differentiation of ES cells and MS5-induced ES cell-derived cells appeared to be applicable to cell therapy for ischemic stroke.

Synthesis and redox behavior of new ferrocene-π-extended-dithiafulvalenes: An approach for anticipated organic conductors

A number of new ferrocene-π-extended-dithiafulvalenes were successfully synthesized as new electron donor compounds. The chemical structures and electrochemical behaviors of these compounds were investigated using several spectroscopic methods. The synthesis of these compounds was achieved using the modified Wittig–Horner cross-coupling reaction using n-BuLi/THF at temperature varies from −78 °C to 0 °C. These new classes of bis(1,3-dithiafulvalene)ferrocenes have the 1,3-dithiole ring system separated by ferrocene as conjugated spacer. The ferrocene-dithiafulvalenes derivatives 9 and 12 were prepared as side products during the synthesis of the targeted compounds as bis(1,3-dithiafulvalene)ferrocenes 8, 10 and 11 in variable yields. The redox properties of the compounds have been investigated by cyclic voltammetry at ambient temperature using tetra-n-butylammonium perchlorate (TBAP) as the supporting electrolyte compared to ferrocene and the derivative 9. In CH2Cl2 on a Pt working electrode and at ambient temperature, two oxidation waves associated with two reduction waves at scan rates 100 mV s−1 were observed for 9 and 12. In contrast the anodic peak potential of bis(1,3-dithiafulvalene)ferrocenes 8, 10 and 11 exhibited two and three oxidation waves associated with two reduction waves.

An improved amide coupling procedure for the synthesis of N-(pyridin-2-yl)amides

Dehydrative amide couplings with 2-pyridylamines suffer from variable yields. A mild and high-yielding synthesis of N-(pyridin-2-yl)amides employing 2-aminopyridine- N-oxides is presented as a solution.

Freshly isolated stromal cells from the infrapatellar fat pad are suitable for a one-step surgical procedure to regenerate cartilage tissue

Stem cell therapies are being evaluated as promising alternatives for cartilage regeneration. We investigated whether stromal vascular fraction cells (SVF) from the infrapatellar (Hoffa) fat pad are suitable for a one-step surgical procedure to treat focal cartilage defects. SVF was harvested from patients undergoing knee arthroplasty (n = 53). Colony-forming unit (CFU) assays, growth kinetics and surface marker profiles were determined, and the chondrogenic differentiation capacity of freshly isolated SVF was assessed after seeding in three-dimensional poly (L-lactic-co-epsilon-caprolactone) scaffolds. SVF yield per fat pad varied between 0.55 and 16 x 10(6) cells. CFU frequency and population doubling time were 2.6 +/- 0.6% and +/-2 days, respectively. Surface marker profiles matched those of subcutaneous-derived adipose-derived stem cells (ASC). CFU from Hoffa SVF showed differentiation toward osteogenic and adipogenic lineages. Cartilage differentiation was confirmed by up-regulation of the cartilage genes sox9, aggrecan, collagen type II and cartilage oligomeric matrix protein (COMP), collagen II immunostaining, Alcian Blue staining and glycosaminoglycan production. Compared with passaged cells, SVF showed at least similar chondrogenic potential. This study demonstrates that SVF cells from the infrapatellar fat pad are suitable for future application in a one-step surgical procedure to regenerate cartilage tissue. SVF shows similar favorable characteristics as cultured ASC, and chondrogenic differentiation even appears to be slightly better. However, because of variable harvesting volumes and yields, SVF from the infrapatellar fat pad might only be applicable for treatment of small focal cartilage defects, whereas for larger osteoarthritic defects subcutaneous adipose tissue depot would be preferable.

Amount and Distribution of Collagen in the Pancreas Have No Effect on Porcine Islet Isolation Outcome

Xenotransplantation of porcine islets of Langerhans is considered to be a possible alternative for clinical islet transplantation. However, porcine islet isolation procedures have been shown to produce highly variable yields between pigs with similar backgrounds. One of the variables that could account for this is the collagen substrate within the pancreas. We determined the amount and distribution of collagen within porcine pancreata as they determined islet isolation outcomes. This study involved the histological examination of 140 porcine pancreata (64 juvenile and 76 adult) and islet isolation from 58 adult organs. To quantify the amount of collagen, tissue samples were stained with Sirius Red. Collagen distribution was determined by assessing the presence of collagen in the endocrine-exocrine interface (the “islet capsule”), in tissue samples double-stained with Sirius Red and anti-insulin. Strong variation in total collagen was observed in both adult and juvenile pigs. The mean collagen content in the juvenile group was significantly lower than that in the adult group. Apparently, the pancreas undergoes a process of fibrosis as pigs age. The vast majority of islets from both adult and juvenile pancreata had no or only a limited collagen capsule. However, islet encapsulation was highly variable between pancreata. We observed no significant correlation between total collagen content or the percentage islet encapsulation and islet yield. Although total collagen content and islet encapsulation show great variability between pancreata, neither the amount nor the distribution of collagen affected porcine islet isolation outcome.

Synthetic analogs for evaluating the influence of N–H⋯S hydrogen bonds on the formation of thioester in acetyl coenzyme a synthase

A series of square planar methylnickel(II) complexes, (dppe)Ni(Me)(SAr) (dppe = 1,2-bis(diphenylphosphino)ethane); 2. Ar = phenyl; 3. Ar = pentafluorophenyl; 4. Ar = o-pivaloylaminophenyl; 5. Ar = p-pivaloylaminophenyl; (depe)Ni(Me)(SAr), (depe = 1,2-bis(diethylphosphino)ethane); 7. Ar = phenyl; 8. Ar = pentafluorophenyl; 9. Ar = o-pivaloylaminophenyl; 10. Ar = p-pivaloylaminophenyl), were synthesized via the reaction of (dppe)NiMe(2) (1) and (depe)NiMe(2) (6) with either the corresponding thiol or disulfide. These complexes were characterized by various spectroscopic methods including (31)P NMR, (1)H NMR, (13)C NMR and infrared spectroscopies and in most cases by X-ray diffraction analyses. Solid state and solution measurements establish that 4 and 9 contain intramolecular N-H...S bonds. Carbonylation of the complexes 2-4, 7-10 leads to (dRpe)Ni(CO)(2) and MeC(O)SAr via the intermediacy of the acylnickel adducts, (dRpe)Ni(C(O)Me)(SAr), detected at low temperature by (31)P NMR spectroscopy. Consistent with experimental observations, density functional theory results reveal that the intramolecular hydrogen bond in 9 stabilizes the acylnickel adduct compared with its non-hydrogen-bonded adduct, 10. Oxidative addition of MeC(O)SC(6)F(5) to (dRpe)Ni(COD) followed by spontaneous decarbonylation proceeds in variable yields generating 3 and 8.

Borehole Drying: A Review of the Situation in the Voltaian Hydrogeological System in Ghana

Groundwater development for potable water supply for rural people in Africa especially in Ghana has in-creased significantly over the past decades. The area underlain by the Paleozoic sedimentary formation (Voltaian System) of the country in particular, has experienced this tremendous change. Groundwater in the study area is normally exploited through boreholes fitted mostly with hand pumps. Though the boreholes exhibit variable yields, most of them have yields greater than 13.5 l/min. Research carried out in the area suggests that there is modern and enough recharge, yet borehole drying is a problem especially those with low or marginal yields. A thorough review of the groundwater exploitation in the area, aimed at explaining the circumstances that might lead to these phenomena on the field, has been conducted. The review shows that boreholes with drill yields of usually <20 l/min, especially those drilled in the wet season, constitute the highest percentage of the dried boreholes. Other construction material such as the filter media may also in-fluence the drying process.

Coalification in Carboniferous sediments from the Lötschberg base tunnel

Vitrinite reflectance (Rr), proximate analysis and carbon isotope composition (δ13C) have been used to characterise coal samples from two zones of Late Carboniferous sediments (Gastern and Ferden) in the Aar massif where they are penetrated by the Lotschberg base tunnel (constructed between 1999 and 2005). Samples are characterised by variable ash yields (21.7–93.9%; dry basis); those with ash yields of less than ~50% and with volatile matter content (V;dry ash-free basis) within the limits 2 < V% ≤ 8 are anthracite. Values of Rr range from 3.89% to 5.17% and indicate coalification to the rank of anthracite and meta-anthracite in both Gastern and Ferden Carboniferous zones. Samples of anthracite and shale from the Gastern Carboniferous exhibit a relatively small range in δ13C values (–24.52‰ to –23.38‰; mean: –23.86‰) and are lighter than anthracite samples from the Ferden Carboniferous (mean: –22.20‰).

BIOPSY INSTRUMENT AND YIELD IN ELECTROMAGNETIC NAVIGATION BRONCHOSCOPY

PURPOSE: Electromagnetic Navigation Bronchoscopy (ENB) increases yield for pulmonary nodules. Variable yields in the literature maybe due differences in technique unrelated to ENB. Most report transbronchial biopsies (TBBx) but others have used multiple sampling techniques. This study assesses Cytology brush (CB) and TBBx on the yield of electromagnetic navigation bronchoscopy.

Synthesis and Phytotoxic Activity of Ozonides

The [4 + 3] cycloaddition of the proper furans with the oxyallyl cation, generated in situ from 2,4-dibromopentan-3-one, produced a series of 8-oxabicyclo [3.2.1]oct-6-en-3-ones. Exposure of the oxabicycles to ozone afforded the corresponding 8,9,10,11-tetraoxatricyclo[5.2.1.1 (2,6)]undecan-4-ones in variable yields (7-100%). The phytotoxic properties of these ozonides (or 1,2,4-trioxolanes) and their oxabicycle precursors were evaluated as the ability to interfere with the growth of Sorghum bicolor and Cucumis sativus seedlings. Among oxabicycles, the highest inhibitory activity was shown by compounds possessing a alpha,beta-unsaturated carbonyl moiety. A differential sensitivity of the two crops was evident with ozonides. The most active compounds were also tested against the weed species Ipomoea grandifolia and Brachiaria decumbens. To the best of our knowledge, this is the first article describing ozonides as potential herbicides.

MALTHUSIAN OVERFISHING AND EFFORTS TO OVERCOME IT ON KENYAN CORAL REEFS

This study examined trends along a gradient of fishing intensity in an artisanal coral reef fishery over a 10-year period along 75 km of Kenya's most populated coastline. As predicted by Malthusian scenarios, catch per unit effort (CPUE), mean trophic level, the functional diversity of fished taxa, and the diversity of gear declined, while total annual catch and catch variability increased along the fishing pressure gradient. The fishery was able to sustain high (approximately 16 Mg x km(-2) x yr(-1)) but variable yields at high fishing pressure due to the dominance of a few productive herbivorous fish species in the catch. The effect of two separate management strategies to overcome this Malthusian pattern was investigated: fisheries area closure and elimination of the dominant and most "competitive" gear. We found that sites within 5 km of the enforced closure showed significantly lower total catch and CPUE, but increased yield stability and trophic level of catch than predicted by regression models normalized for fishing effort. Sites that had excluded illegal beach seine use through active gear management exhibited increased total catch and CPUE. There was a strong interaction between closure and gear management, which indicates that, for closures to be effective at increasing catch, there must be simultaneous efforts at gear management around the periphery of the closures. We propose that Malthusian effects are responsible for the variation in gear and catch and that active management through reduced effort and reductions in the most competitive gear have the greatest potential to increase the functional and trophic diversity and per-person productivity.