1,720 research outputs found

    Ultraviolet photodepletion spectroscopy of dibenzo-18-crown-6-ether complexes with alkali metal cations

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    Ultraviolet photodepletion spectra of dibenzo-18-crown-6-ether complexes with alkali metal cations (M+-DB18C6, M = Cs, Rb, K, Na, and Li) were obtained in the gas phase using electrospray ionization quadrupole ion-trap reflectron time-of-flight mass spectrometry. The spectra exhibited a few distinct absorption bands in the wavenumber region of 35450āˆ’37800 cm^(āˆ’1). The lowest-energy band was tentatively assigned to be the origin of the S_0-S_1 transition, and the second band to a vibronic transition arising from the ā€œbenzene breathingā€ mode in conjunction with symmetric or asymmetric stretching vibration of the bonds between the metal cation and the oxygen atoms in DB18C6. The red shifts of the origin bands were observed in the spectra as the size of the metal cation in M^+-DB18C6 increased from Li^+ to Cs^+. We suggested that these red shifts arose mainly from the decrease in the binding energies of larger-sized metal cations to DB18C6 at the electronic ground state. These size effects of the metal cations on the geometric and electronic structures, and the binding properties of the complexes at the S_0 and S_1 states were further elucidated by theoretical calculations using density functional and time-dependent density functional theories

    Nitrogen Use Efficiency of Late Fall-Applied Urea and Pig Slurry for Regrowth of Perennial Ryegrass Sward

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    Pig slurry is the most important organic resource in Korea, as estimated to be more than 15% of recycled animal manure. The use of pig slurry as an alternative organic fertilizer is the most viable recycling option as it is produced in large amount on pig farms that has usually less or not surface for cultivation of forage crops in Korea. Perennial grasses in grassland system regrow successively after harvests by cutting or grazing. The regrowth yield at each harvest would be a crucial determinant for the productivity of sward. During vegetative regrowth, soil mineral N and N reserves meet the N requirements for shoot regrowth. The aims of this study are to estimate the N use efficiency of urea and pig slurry applied at late fall in relation to the N availability for restoring organic reserves and constructing ultimate regrowth biomass during successive three cycle of regrowth of perennial ryegrass sward

    S Nutrition Is Involved in Alleviation of Damage of Photosynthetic Organelles by Salt Stress in Kentucky Bluegrass (\u3cem\u3ePoa pratensis\u3c/em\u3e L.)

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    Salt-stress is considered as one of the major environmental factor limiting plant growth and productivity. It has been well reported that salt stress induce the reduction of stomatal density and number leading to poor gaseous exchange which resulted in decrease of photosynthesis is associated with inhibition of several enzymes related to the Calvin cycle such as RuBisCo. In addition, salt stress decreases photosynthetic pigments such as chlorophyll and carotenoid which has important role in photosynthesis. Sulfur (S) is one of six macronutrients needed for proper plant growth and development. In our previous work, we found that sulfur nutrition has significant role in ameliorating the damaged in photosynthetic organelles caused by Fe-deficiency in oilseed rape (Muneer et al., 2014). In addition, application of sulfur mitigated the adverse effects of heavy metals stress by enhancing plant growth, chlorophyll content and net photosynthetic rate. Despite extensive researches attempting to elucidate the interactions between external sulfur supplies and stress tolerance, to our knowledge, the responses of the photosynthetic mechanism to combined S deficiency and salt stress have not yet been fully investigated. In this study, therefore, we hypothesized that S nutrition affects photosynthetic organs to salt stress, so that may involve in alleviating negative impact of salt stress in Kentucky bluegrass. To test this hypothesis, the responses of photosynthetic parameters, thylakoid protein complexes and ion uptake were compared for 21 days of four S and salt stress combined treatments; sulfur sufficient without salt stress (+S/non-salt, control), present of sulfur with salt stress (+S/salt), sulfur deprivation without salt stress (-S/non-salt) and sulfur deprivation and salt stress (-S/salt)

    Age-related changes in cervical sagittal range of motion and alignment

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    Study Designā€ƒRetrospective cohort study. Objectiveā€ƒTo compare sagittal cervical range of motion (ROM) and alignment in young versus middle-aged adults. Methodsā€ƒOne hundred four asymptomatic adults were selected randomly out of 791 subjects who underwent lateral cervical radiographs in neutral, flexion, and extension positions. They were divided into two groups: young (age 20 to 29, 52 people) and middle-aged adults (age 50 to 59, 52 people). We determined the ROMs of upper cervical (occipitalā€“C2 angle), midcervical (C2ā€“C7 angle), and cervicothoracic spine (cervicosternal angle). We compared the alignment differences of the two groups by calculating the distances between C2 and C7 plumb lines, and C2 central-offset distance. Resultsā€ƒIn neutral position, there was no significant difference between young and middle-aged adults. However, in flexion, C2ā€“C7 angle, distance between C2ā€“C7 plumb lines, and C2 central-offset distance decreased with age. In extension, C2ā€“C7 angle and C2 central-offset distance decreased with age. During flexion and extension, midcervical ROM and the range of C2 central-offset distance decreased in the middle-aged group. However, there was no difference between the two age groups in the ROM of the upper cervical and the cervicothoracic regions during flexion and extension. Conclusionā€ƒWe found that, despite of the presence of age-related cervical alignment changes, the only difference between the two groups was in the sagittal ROM of the midcervical spine during flexion and extension. Only the ROM of the midcervical spine appears to change significantly, consistent with findings that these levels are most likely to develop both symptomatic and asymptomatic degenerative changes

    Radiographic comparison between cervical spine lateral and whole-spine lateral standing radiographs

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    Study Designā€ƒRetrospective radiologic study. Objectiveā€ƒThe sagittal alignment of the cervical spine can be evaluated using either a lateral cervical radiograph or a whole-spine lateral view on which the cervical spine is included. To our knowledge, however, no report has compared the two. The purpose of this work is to identify the difference in radiographic parameters between the cervical spine lateral view and the whole-spine lateral view. Methodsā€ƒWe retrospectively analyzed 59 adult patients suffering from neck pain with cervical spine lateral radiographs and whole-spine lateral radiographs from November 2007 to December 2011. The radiographs were measured using standard techniques to obtain the following parameters from the two different radiographs: occipitalā€“C2 angle, C2ā€“C7 angle, C7ā€“sternal angle, sternal slope, T1 slope, C2 central offset distance, the distance between C2 and C7 plumb lines, C4 anteroposterior (AP) diameter, the ratio of C2 central off distance to C4 AP diameter, the ratio of plumb lines' distance to C4 AP diameter. Resultsā€ƒWe found that the occipitalā€“C2 angle, sternal slope, and C4 AP diameter were similar, but the C2ā€“C7 angle, C7ā€“sternal angle, T1 slope, C2 central offset distance, distance between C2 and C7 plumb lines, ratio of C2 central off distance to C4 AP diameter, and ratio of plumb lines' distance to C4 AP diameter were different. However, the error of measurement was greater than the small angular and linear differences between the two views. Conclusionsā€ƒMost numerical values of the measured radiographic parameters appear to be different between the two views. However, the two views are comparable because the numerical differences were smaller than the errors of measurement

    Delayed surgical intervention in central cord syndrome with cervical stenosis

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    Study Designā€ƒReview of the literature. Objectiveā€ƒIt is generally accepted that surgical treatment is necessary for central cord syndrome (CCS) with an underlying cervical stenosis. However, the surgical timing for decompression is controversial in spondylotic cervical CCS. The purpose of this study is to review the results of early and delayed surgery in patients with spondylotic cervical CCS. Methodsā€ƒMEDLINE was searched for English-language articles on CCS. There were 1,653 articles from 1940 to 2012 regarding CCS, 5 of which dealt with the timing of surgery for spondylotic cervical CCS. Resultsā€ƒAll five reports regarding the surgical timing of spondylotic cervical CCS were retrospective. Motor improvement, functional independence measures, and walking ability showed similar improvement in early and late surgery groups in the studies with follow-up longer than 1 year. However, greater improvement was seen in the early surgery group in the studies with follow-up shorter than 1 year. The complication rates did not show a difference between the early and late surgery groups. However, there are controversies regarding the length of intensive care unit stay or hospital stay for the two groups. Conclusionsā€ƒThere was no difference in motor improvement, functional independence, walking ability, and complication rates between early and late surgery for spondylotic cervical CCS

    Isolation and characterization of NgRLK1, a receptor-like kinase of Nicotiana glutinosa that interacts with the elicitin of Phytophthora capsici

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    Elicitins, extracellular proteins from Phytophthora fungi, elicit a hypersensitivity response (HR), including systemic acquired resistance, in some plants. The elicitin capsicein (~10Ā kDa) was purified by FPLC from culture filtrates of P. capsici. Purified native and recombinant capsicein induced a hypersensitive response in leaves of the non-host plants Nicotiana glutinosa and Brassica rapa subsp. pekinensis. To search for candidate capsicein-interacting proteins from N. glutinosa, a yeast two-hybrid assay was used. We identified a protein interactor that is homologous to a serine/threonine kinase of the plant receptor-like kinase (RLK) group and designated it NgRLK1. The ORF of NgRLK1 encodes a polypeptide of 832 amino acids (93,490Ā Da). A conserved domain analysis revealed that NgRLK1 has structural features typical of a plant RLK. NgRLK1 was autophosphorylated, with higher activity in the presence of Mn2+ than Mg2+

    Asymptomatic stenosis in the cervical and thoracic spines of patients with symptomatic lumbar stenosis

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    Study Designā€ƒRetrospective study. Objectiveā€ƒStudies on age-related degenerative changes causing concurrent stenoses in the cervical, thoracic, and lumbar spines (triple stenosis) are rare in the literature. Our objectives were to determine: (1) the incidence of asymptomatic radiologic cervical and thoracic stenosis in elderly patients with symptomatic lumbar stenosis, (2) the incidence of concurrent radiologic spinal stenosis in the cervical and thoracic spines, and (3) the radiologic features of cervical stenosis that might predict concurrent thoracic stenosis. Methodsā€ƒWhole-spine T2 sagittal magnetic resonance images of patients older than 80 and diagnosed with lumbar spinal stenosis between January 2003 and January 2012 were evaluated retrospectively. We included patients with asymptomatic spondylotic cervical and thoracic stenosis. We measured the anteroposterior diameters of the vertebral body, bony spinal canal, and spinal cord, along with the Pavlov ratio and anterior or posterior epidural stenosis at the level of the disk for each cervical and thoracic level. We compared the radiologic parameters between the subgroups of cervical stenosis with and without thoracic stenosis. Resultsā€ƒAmong the 460 patients with lumbar stenosis, 110 (23.9%) had concurrent radiologic cervical stenosis and 112 (24.3%) had concurrent radiologic thoracic stenosis. Fifty-six patients (12.1%) had combined radiologic cervical and thoracic stenosis in addition to their symptomatic lumbar stenosis (triple stenosis). Anterior epidural stenosis at C7ā€“T1 was associated with a high prevalence of thoracic stenosis. Conclusionsā€ƒIt appears that asymptomatic radiologic cervical and thoracic stenosis is common in elderly patients with symptomatic lumbar stenosis
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