RESUMO
Organic farming was developed to reduce agriculture's negative impacts on the environment and enhance biodiversity for sustainable productivity in agricultural ecosystems, but the long-term effectiveness of its application in Japanese rice paddies is unclear. We sought to understand how long-term organic farming affects the abundance of animals in both the rice growth and fallow seasons, and how soil properties change. We investigated the abundance of fishes, frogs, beetles, and shellfish in the floodwater in summer, and the abundance of earthworms (mainly Enchytraeidae), arthropods (spiders and springtails), and soil properties in aerobic soils in autumn. We examined fields which had been farmed organically for 10 and 18 years in Tochigi, Japan. Fields farmed with conventional management, located close to the selected organic fields, were used as a control. All selected fields were located in a valley, which is the typical landscape of a traditional Japanese farming village, called a yatsuda in Japanese. The results showed an increase in soil organic carbon, total nitrogen, and available phosphorus in plowed soils that had been converted from conventional to organic farming both 10 and 18 years earlier. However, the abundance of various animals were not affected significantly by long-term organic rice farming, other than arthropods in the aerobic soils that had been farmed organically for 18 years. The quantity of most animals in floodwater and fallow season soil was unaffected by long-term organic rice farming in the yatsuda paddy fields, probably due to the circumstances and similar irrigation systems for both conventional and organic rice farming, as well as lighter doses of agrochemical application for conventional rice cultivation.
Assuntos
Oryza , Solo , Agricultura , Animais , Carbono/análise , Ecossistema , Monitoramento Ambiental , Japão , Agricultura OrgânicaRESUMO
In the tissue characterization of plaques using magnetic resonance imaging (MRI), T1-weighted imaging is important. However, T1-weighted imaging are obtained by various imaging methods, and show different contrasts depending on parameters such as repetition time, echo time, and inversion time. To evaluate the tissue characterization of plaques using MRI, the characteristics are estimated and evaluated using the strength of the plaque-to-muscle signal intensity ratio (PMR), which is the value obtained by dividing the signal intensity of the plaque by that of the sternocleidomastoid muscle or myocardium. In the present research, we aim to obtain the PMR by phantom experiment and grasp the image characteristics for T1 and T2 values of different T1-weighted imaging methods. In addition, since the PMR of the conventional spin echo (SE) method of T1-weighted imaging (two-dimensional (2D) T1WI SE) is reported to have high discrimination ability in plaque tissue characterization, the experimental results were compared with those of 2D T1WI SE. Among the protocols examined, 3D sampling perfection with application optimized contrasts using different flip angle evolutions, T1-variable, motion-sensitized driven equilibrium (1-axis 300 ms2*mT/m) + had the same tissue characterization ability as 2D T1 WI SE, and was the most suitable imaging method. Moreover, in the gradient echo method, the effect of T2 values was smaller than that of 2D T1 WI SE, and it was suggested that the PMR of the plaque may be lowered when there is a change in the tissue properties that the T2 value and T1 value are prolonged due to liquefaction. The results of this phantom experiment are expected help in selecting the imaging method aimed at optimization and the image characteristics of different T1-weighted imaging method can be grasped.
Assuntos
Imageamento Tridimensional , Imageamento por Ressonância Magnética , Placa Aterosclerótica , Meios de Contraste , Humanos , Imagens de Fantasmas , Placa Aterosclerótica/diagnóstico por imagemRESUMO
Three new fusarielins, 3-epi-fusarielin H (1), 3-O-methyl-fusarielin H (2), and 3-O-methyl-epi-fusarielin H (3), were isolated from the fungus Fusarium sp. together with the known analogues, fusarielins F (4) and G (5). The structures of these compounds were elucidated by analysis of their ESI-HRTOFMS, 1D and 2D NMR spectroscopic data. The new compounds exhibited weak antibacterial effect against Staphylococcus aureus.
Assuntos
Antibacterianos/química , Antifúngicos/química , Fusarium/química , Naftalenos/química , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Compostos de Epóxi/química , Compostos de Epóxi/farmacologia , Fermentação , Humanos , Espectroscopia de Ressonância Magnética , Naftalenos/farmacologiaRESUMO
In three-dimensional (3D) T1-weighted magnetic resonance imaging used for tissue characterization of coronary plaques, the contrast for electrocardiographic synchronization may vary according to the R-R interval (RR). The coronary artery plaque image shows suppression of the fluid compartment signal for the coronary artery luminal blood as well as the fat signal in the region of interest; in addition, it is necessary to ensure that the value of the plaque-to-muscle signal intensity ratio (PMR) does not change according to the difference in RR. In the current study, the phantom review and clinical data suggested that the PMR changes that occur due to the differences in RR can be minimized by adjusting the inversion time (TI) in the range of the required black blood effect. Moreover, the signal-to-noise ratio (SNR), which varies according to the difference between the RR and the TI, was determined to identify the maximum value flip angle (FA) value that would lead to improvement in the SNR. Thus, signal suppression of the PMR, SNR, and the fluid compartment of the coronary artery luminal blood can be controlled using different RRs with the relational expressions for calculating optimal TI and FA.
Assuntos
Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Placa Aterosclerótica/diagnóstico por imagem , Idoso , Humanos , Imageamento por Ressonância Magnética/instrumentação , Masculino , Imagens de Fantasmas , Razão Sinal-Ruído , Fatores de TempoRESUMO
Additions of adamantylidene (Ad) to M3 N@Ih -C80 (M=Sc, Lu) and Sc3 N@D5h -C80 have been accomplished by photochemical reactions with 2-adamantyl-2,3'-[3H]-diazirine (1). In M3 N@Ih -C80 , the addition led to rupture of the [6,6]- or [5,6]-bonds of the Ih -C80 cage, forming the [6,6]-open fulleroid as the major isomer and the [5,6]-open fulleroid as the minor isomer. In Sc3 N@D5h -C80 , the addition also proceeded regioselectively to yield three major isomeric Ad mono-adducts, despite the fact that there are nine types of C-C bonds in the D5h -C80 cage. The molecular structures of the seven Ad mono-adducts, including the positions of the encaged trimetallic nitride clusters, have been unambiguously determined through single-crystal XRD analyses. Furthermore, results have shown that stepwise addition of Ad to Lu3 N@Ih -C80 affords several Ad bis-adducts, two of which have been isolated and characterized. The X-ray structure of one bis-adduct clearly revealed that the second Ad addition took place at a [6,6]-bond close to an endohedral metal atom. Theoretical calculations have also been performed to rationalize the regioselectivity.
RESUMO
To investigate the intrinsic reactivity of atomic nitrogen, which had previously been accomplished only by examining its decay in the gas phase using special equipment, a nitrogen atom was inserted into a series of molecule-encapsulating C60 and C70 fullerenes. Among the studied endofullerenes, H2 @C70 was able to encapsulate an additional nitrogen atom within the fullerene cage under radiofrequency plasma conditions. The product was analyzed by ESR spectroscopy and mass spectrometry in solution, which revealed that the nitrogen atom with a quartet ground state does not react but weakly interact with the H2 molecule, thus demonstrating the utility of such fullerenes as "nanoflasks".
RESUMO
We compared the chemical reactivity of D2d(23)-C84 and that of Sc2C2@D2d(23)-C84, both having the same carbon cage geometry, in the photolysis of 2-adamantane-2,3'-[3H]-diazirine, to clarify metal-atom doping effects on the chemical reactivity of the carbon cage. Experimental and computational studies have revealed that the chemical reactivity of the D2d(23)-C84 carbon cage is altered drastically by endohedral Sc2C2 doping. The reaction of empty D2d(23)-C84 with the diazirine under photoirradiation yields two adamantylidene (Ad) adducts. NMR spectroscopic studies revealed that the major Ad monoadduct (C84(Ad)-A) has a fulleroid structure and that the minor Ad monoadduct (C84(Ad)-B) has a methanofullerene structure. The latter was also characterized using X-ray crystallography. C84(Ad)-A is stable under photoirradiation, but it interconverted to C84(Ad)-B by heating at 80 °C. In contrast, the reaction of endohedral Sc2C2@D2d(23)-C84 with diazirine under photoirradiation affords four Ad monoadducts (Sc2C2@C84(Ad)-A, Sc2C2@C84(Ad)-B, Sc2C2@C84(Ad)-C, and Sc2C2@C84(Ad)-D). The structure of Sc2C2@C84(Ad)-C was characterized using X-ray crystallography. Thermal interconversion of Sc2C2@C84(Ad)-A and Sc2C2@C84(Ad)-B to Sc2C2@C84(Ad)-C was also observed. The reaction mechanisms of the Ad addition and thermal interconversion were elucidated from theoretical calculations. Calculation results suggest that C84(Ad)-B and Sc2C2@C84(Ad)-C are thermodynamically favorable products. Their different chemical reactivities derive from Sc2C2 doping, which raises the HOMO and LUMO levels of the D2d(23)-C84 carbon cage.
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We report that Ce@C2v (9)-C82 forms a centrosymmetric dimer when co-crystallized with Ni(OEP) (OEP = octaethylporphyrin dianion). The crystal structure of {Ce@C2v (9)-C82 }2 â 2[Ni(OEP)]â 4 C6 H6 shows that a new C-C bond with a bond length of 1.605(5)â Å connects the two cages. The high spin density of the singly occupied molecular orbital (SOMO) on the cage and the pyramidalization of the cage are factors that favor dimerization. In contrast, the treatment of Ni(OEP) with M@C2v (9)-C82 (M = La, Sc, and Y) results in crystallization of monomeric endohedral fullerenes. A systematic comparison of the X-ray structures of M@C2v (9)-C82 (M = Sc, Y, La, Ce, Gd, Yb, and Sm) reveals that the major metal site in each case is located at an off-center position adjacent to a hexagonal ring along the C2 â axis of the C2v (9)-C82 cage. DFT calculations at the M06-2X level revealed that the positions of the metal centers in these metallofullerenes M@C2v (9)-C82 (M = Sc, Y, and Ce), as determined by single-crystal X-ray structure studies, correspond to an energy minimum for each compound.
RESUMO
The self-assembly of covalently linked dyad 1a of cyclometalated organoplatinum(II) complex and fullerene afforded alternating multilayers of electron-rich and -deficient molecular components. On the other hand, the coassembly of 1a with organoplatinum(II) complex 2 having no fullerene moiety gave an exfoliated form of the multilayers, by inhibiting the interdigitation of organoplatinum(II) complex moieties of 1a. The coassembled 1a/2 transports both of the photogenerated holes and electrons, while the self-assembled 1a allows only the transportation of electrons under the same conditions.
RESUMO
The reaction mechanism of the Diels-Alder reaction of paramagneticendohedral metallofullerene, La@C82, and 1,2,3,4,5-pentamethylcyclopentadiene was studied theoretically and experimentally. Theoretical calculations revealed that this reaction proceeds via a concerted mechanism that includes formation of a stable intermediate. The activation energy of a retro-Diels-Alder reaction was also studied experimentally, which is in good agreement with theoretical results.
RESUMO
Fullerene crystals or films have drawn much interest because they are good candidates for use in the construction of electronic devices. The results of theoretical calculations revealed that the conductivity properties of I(h)-C(80) endohedral metallofullerenes (EMFs) vary depending on the encapsulated metal species. We experimentally investigated the solid-state structures and charge-carrier mobilities of I(h)-C(80) EMFs La(2)@C(80), Sc(3)N@C(80), and Sc(3)C(2)@C(80). The thin film of Sc(3)C(2)@C(80) exhibits a high electron mobility µ = 0.13 cm(2) V(-1) s(-1) under normal temperature and atmospheric pressure, as determined using flash-photolysis time-resolved microwave conductivity measurements. This electron mobility is 2 orders of magnitude higher than the mobility of La(2)@C(80) or Sc(3)N@C(80).
RESUMO
Metal positions in endohedral metallofullerenes (EMFs) are of special importance because their molecular symmetry and intrinsic properties are strongly influenced by the location and motion of the encapsulated metals. X-ray analyses of the cocrystals of Gd@C(2v)(9)-C(82) with nickel(II) octaethylporphyrin [Ni(II)(OEP)] reveal that the Gd(3+) cation is off-center, being located under a hexagonal ring along the 2-fold axis of the C(2v)(9)-C(82) cage. This result is in sharp contrast to that of a previous study, showing that Gd@C(2v)(9)-C(82) has an anomalous endohedral structure, with the metal being positioned over a [6,6] bond, which is opposite to the hexagonal ring along the C(2) axis (Phys. Rev. B 2004, 69, 113412). In agreement with theoretical calculations and related studies, it is conclusive that the single rare-earth metal in M@C(2v)(9)-C(82) always tends to coordinate with the hexagonal ring along the 2-fold axis, instead of interacting with the [6,6] bond on the other end, regardless of the type of metal atom.
RESUMO
We prepared an organic conductor crystal having extremely high electron mobility, in which the adamantylidene (Ad) derivative of La@C(82) (an endohedral metallofullerene known as a n-type semiconductor) is aligned in an orderly fashion. The single-component crystal exhibits high electron mobility of µ > 10 cm(2) V(-1) s(-1) along the c axis under normal temperatures and pressures in the atmosphere, as shown by flash-photolysis time-resolved microwave conductivity (TRMC) measurements, which are the highest of reported organic conductors measured by TRMC. According to density functional calculations, the single crystal of La@C(82)Ad is semi-metallic, with a small band gap of 0.005 eV.
Assuntos
Elétrons , Fulerenos/química , Lantânio/química , Adamantano/química , Cristalografia por Raios X , Modelos MolecularesRESUMO
We describe the regioselective cycloaddition of La(2)@I(h)-C(80) with tetracyanoethylene oxide (TCNEO), which enabled the formation of the corresponding adduct having a tetracyanotetrahydrofuran moiety. X-ray crystallographic analysis revealed that the cycloaddition took place as a [5,6] addition. Along with dynamic swing motion of the metal atoms, the results of this electrochemical study demonstrate that TCNEO addition enhanced the electron-accepting character of La(2)@I(h)-C(80) and that the first reduction potential of the adduct reached -0.21 V versus the ferrocene/ferrocenium couple, which is the lowest value reported for endohedral metallofullerenes and their derivatives to date.
RESUMO
Bis-functionalization of endohedral metallofullerene La(2)@C(80) by carbene addition is reported herein. Adducts were characterized using spectroscopic and single-crystal X-ray structure analyses. Crystallographic data for bisadduct La(2)@C(80)(CClPh)Ad (3, Ad = adamantylidene) revealed that both carbene additions occur at the 6,6-bond junction on the C(80) cage with ring cleavages and that La atoms are positioned collinearly with spiro carbons. It is noteworthy that the La-La distance in 3 is highly elongated by carbene bis-functionalization compared to the distance in pristine La(2)@C(80) and reported functionalized derivatives. The metal positions were confirmed through density functional calculations.
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We defined a spiritual pain as feelings of failure and regret at end-of-life, followed by hopelessness and worthlessness in patient's own life. In Japanese, spiritual pain should be assessed in patient's dignity, psycho-social factor, and prognostic stage, not only in religious context. And patient's spirituality should be supported with providing pain and symptom relief based on human relationships. "Sterbebegleitung" is a German proverb, introduced by Alfons Deeken, and seemed to be a suggestive word for such hope-recovering relationships.
Assuntos
Neoplasias/psicologia , Humanos , Espiritualidade , Revelação da VerdadeRESUMO
Thermal carbosilylation of endohedral dimetallofullerene La(2)@I(h)-C(80) with silirane (silacyclopropane) is reported herein for the first time. Two diastereomers of the carbosilylated La(2)@I(h)-C(80) have been isolated and characterized. The fascinating molecular structure of one diastereomer of the carbosilylated derivatives has been determined unambiguously using X-ray crystallographic analysis. Detailed characteristics of the molecular structures including their metal atom movements have also been revealed using NMR spectroscopic studies and computational calculations. Results revealed that two La atoms move dynamically inside the carbon sphere. Furthermore, electrochemical study has demonstrated that carbosilylation is effective to fine-tune the La(2)@I(h)-C(80) electronic properties.
RESUMO
This study focuses on the function of the gene praR that encodes a putative transcription factor in Azorhizobium caulinodans ORS571, a microsymbiont of Sesbania rostrata. The praR gene is a homolog of the phrR gene of Sinorhizobium medicae WSM419, and the praR and phrR homologs are distributed throughout the class Alphaproteobacteria. The growth and nitrogen fixation activity of an A. caulinodans praR deletion mutant in the free-living state were not significantly different from those of the wild-type strain. However, the stem nodules formed by the praR mutant showed lower nitrogen fixation activity than the wild-type stem nodules. Microscopy revealed that infected host cells with an oval or elongated shape were observed at early stages in the nodules formed by the praR mutant, but these infected cells gradually fell into two types. One maintained an oval or elongated shape, but the vacuoles in these cells gradually enlarged and the bacteria gradually disappeared. The other cells were shrunken with bacteria remaining inside. Microarrays revealed that genes homologous to the reb genes of Caedibacter taeniospiralis were highly expressed in the praR mutant. Furthermore, the stem nodules formed by an A. caulinodans mutant with a deletion of praR and reb-homologous genes showed high nitrogen fixation activity, comparable to that of the wild-type stem nodules, and were filled with oval or elongated host cells. These results suggest that PraR controls the expression of the reb-homologous genes and that high expression of reb-homologous genes causes aberrance in A. caulinodans-S. rostrata symbiosis.
Assuntos
Azorhizobium caulinodans/fisiologia , Proteínas de Bactérias/fisiologia , Regulação Bacteriana da Expressão Gênica , Sesbania/microbiologia , Simbiose , Fatores de Transcrição/fisiologia , Azorhizobium caulinodans/genética , Proteínas de Bactérias/genética , Deleção de Genes , Perfilação da Expressão Gênica , Microscopia , Fixação de Nitrogênio , Raízes de Plantas/citologia , Raízes de Plantas/microbiologia , Homologia de Sequência de Aminoácidos , Sesbania/citologia , Fatores de Transcrição/genéticaRESUMO
The first regioselective functionalization of La@C(82) by two different groups has been performed. Bis-adducts of La@C(82) with Cp* and adamantylidene were synthesized by using two different routes and characterized. Spectroscopic analysis and theoretical calculations reveal that the addition position is controlled by the charge density and p-orbital axis vector value of the fullerene cage.
RESUMO
The two regioisomers of endohedral pyrrolidinodimetallofullerenes M(2)@I(h)-C(80)(CH(2))(2)NTrt (M = La, Ce; Trt = trityl) were synthesized, isolated, and characterized. X-ray crystallographic analyses of [6,6]-La(2)@I(h)-C(80)(CH(2))(2)NTrt and [6,6]-Ce(2)@I(h)-C(80)(CH(2))(2)NTrt revealed that the encapsulated metal atoms are located at the slantwise positions on the mirror plane that parallels the pyrrolidine ring. Paramagnetic NMR analyses of [6,6]- and [5,6]-Ce(2)@I(h)-C(80)(CH(2))(2)NTrt were also carried out to clarify the metal positions. As for the [6,6]-adduct, the metal positions obtained by paramagnetic NMR analysis agree well with the X-ray structure. In contrast, paramagnetic NMR analysis of the [5,6]-adduct showed that the two Ce atoms are collinear with the pyrrolidine ring. We also compared the observed paramagnetic effects of the pyrrolidinodimetallofullerenes with those of other cerium-encapsulating fullerene derivatives such as bis-silylated Ce(2)@I(h)-C(80) and a carbene adduct of Ce(2)@I(h)-C(80). We found that the metal positions can be explained by the electrostatic potential maps of the corresponding [6,6]- and [5,6]-adducts of [I(h)-C(80)(CH(2))(2)NTrt](6-). These findings clearly show that metal positions inside fullerene cages can be controlled by means of the addition positions of the addends. In addition, the radical anions of the pyrrolidinodimetallofullerenes were prepared by bulk controlled-potential electrolysis and characterized by X-band EPR spectral study.