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Nissen, Mark S,Kumar, G N Mohan,Youn, Buhyun,Knowles, D Benjamin,Lam, Ka Sum,Ballinger, W Jordan,Knowles, N Richard,Kang, Chulhee American Society of Plant Physiologists 2009 The Plant cell Vol.21 No.3
<P>Potato (Solanum tuberosum) multicystatin (PMC) is a crystalline Cys protease inhibitor present in the subphellogen layer of potato tubers. It consists of eight tandem domains of similar size and sequence. Our in vitro results showed that the pH/PO(4)(-)-dependent oligomeric behavior of PMC was due to its multidomain nature and was not a characteristic of the individual domains. Using a single domain of PMC, which still maintains inhibitor activity, we identified a target protein of PMC, a putative Cys protease. In addition, our crystal structure of a representative repeating unit of PMC, PMC-2, showed structural similarity to both type I and type II cystatins. The N-terminal trunk, alpha-helix, and L2 region of PMC-2 were most similar to those of type I cystatins, while the conformation of L1 more closely resembled that of type II cystatins. The structure of PMC-2 was most similar to the intensely sweet protein monellin from Dioscorephyllum cumminisii (serendipity berry), despite a low level of sequence similarity. We present a model for the possible molecular organization of the eight inhibitory domains in crystalline PMC. The unique molecular properties of the oligomeric PMC crystal are discussed in relation to its potential function in regulating the activity of proteases in potato tubers.</P>
Søren Ohrt-Nissen,Benny Dahl,Martin Gehrchen 대한척추신경외과학회 2018 Neurospine Vol.15 No.2
The surgical treatment of adolescent idiopathic scoliosis (AIS) involves 3-dimensional curve correction with multisegmental pedicle screws attached to contoured bilateral rods. The substantial corrective forces exert a high level of stress on the rods, and the ability of the rod to withstand these forces without undergoing permanent deformation relies on its biomechanical properties. These properties, in turn, are dependent on the material, diameter, and shape of the rod. The surgical treatment of AIS is characterized by the requirement for a special biomechanical profile that may differ substantially from what is needed for adult deformity surgery. This overview summarizes the current knowledge of rod biomechanics in frequently used rod constructs, with a particular focus on translational research between biomechanical studies and clinical applicability in AIS patients.
Yoon, Sukhwan,Nissen, Silke,Park, Doyoung,Sanford, Robert A.,Loffler, Frank E. American Society for Microbiology 2016 Applied and environmental microbiology Vol.82 No.13
<P>Bacteria capable of reduction of nitrous oxide (N2O) to N-2 separate into clade I and clade II organisms on the basis of nos operon structures and nosZ sequence features. To explore the possible ecological consequences of distinct nos clusters, the growth of bacterial isolates with either clade I (Pseudomonas stutzeri strain DCP-Ps1, Shewanella loihica strain PV-4) or clade II (Dechloromonas aromatica strain RCB, Anaeromyxobacter dehalogenans strain 2CP-C) nosZ with N2O was examined. Growth curves did not reveal trends distinguishing the clade I and clade II organisms tested; however, the growth yields of clade II organisms exceeded those of clade I organisms by 1.5- to 1.8-fold. Further, whole-cell half-saturation constants (K(s)s) for N2O distinguished clade I from clade II organisms. The apparent Ks values of 0.324 +/- 0.078 mu M for D. aromatica and 1.34 +/- 0.35 mu M for A. dehalogenans were significantly lower than the values measured for P. stutzeri (35.5 +/- 9.3 mu M) and S. loihica (7.07 +/- 1.13 mu M). Genome sequencing demonstrated that Dechloromonas denitrificans possessed a clade II nosZ gene, and a measured Ks of 1.01 +/- 0.18 mu M for N2O was consistent with the values determined for the other clade II organisms tested. These observations provide a plausible mechanistic basis for why the relative activity of bacteria with clade I nos operons compared to that of bacteria with clade II nos operons may control N2O emissions and determine a soil's N2O sink capacity.</P>
Sidsel Fruergaard,Søren Ohrt-Nissen,Benny Dahl,Nicolai Kaltoft,Martin Gehrchen 대한척추신경외과학회 2019 Neurospine Vol.16 No.2
Objective: Magnetic resonance imaging (MRI)-verified neural axis abnormalities (NAAs) have been described in adolescent idiopathic scoliosis (AIS), and several risk factors have been associated with the presence of NAAs in AIS patients. However, the clinical significance of these findings is unclear. The purpose of the present study was to determine the prevalence of NAAs in a large consecutive cohort of AIS patients and to evaluate the clinical significance of previously proposed risk factors. Methods: We prospectively included AIS patients referred to a tertiary facility for evaluation. Full-spine MRI scans were performed on all included patients irrespective of curve magnitude or proposed treatment modality. MRI scans were prospectively analyzed by a neuroradiologist and the pathologic findings were confirmed by a second independent radiologist. Results: NAA was observed in 34 of the 381 patients (8.9%): 32 patients had a syrinx, 1 patient had an arachnoid cyst, and 1 patient had a Chiari malformation. Four patients were referred for a neurosurgical evaluation but none received any neurosurgical treatment. No statistically significant difference was observed between the NAA and non-NAA groups in terms of sex, major curve size, thoracic kyphosis, left thoracic curve, curve convexity, curve progression, or level of pain (p>0.05). Conclusion: In this prospective study examining the risk factors for NAA in AIS patients, we found that previously proposed risk factors could not predict the MRI outcomes. The finding of an NAA had no clinical implications and we do not support MRI scans as a routine diagnostic modality in all AIS patients.
Experimental investigation on splashing and nonlinear fingerlike instability of large water drops
Yoon, S.S.,Jepsen, R.A.,Nissen, M.R.,O’Hern, T.J. Academic Press 2007 Journal of Fluids and Structures Vol.23 No.1
<P><B>Abstract</B></P><P>The fluid physics of the splashing and spreading of a large-scale water drop is experimentally observed and investigated. New phenomena of drop impact that differ from the conventional Rayleigh–Taylor instability theory are reported. Our experimental data shows good agreement with previous work at low Weber number but the number of fingers or instabilities begins to deviate from the R–T equation of Allen at high Weber numbers. Also observed were multiple waves (or rings) on the spreading liquid surface induced from pressure bouncing (or pulsation) within the impacting liquid. The first ring is transformed into a radially ejecting spray whose initial speed is accelerated to a velocity of 4–5 times that of the impacting drop. This first ring is said to be “splashing,” and its structure is somewhat chaotic and turbulent, similar to a columnar liquid jet surrounded by neighboring gas jets at relatively high impact speed. At lower impact speeds, splashing occurs as a crown-shaped cylindrical sheet. A second spreading ring is observed that transforms into fingers in the circumferential direction during spreading. At higher Weber number, the spreading of a third ring follows that of the second. This third ring, induced by the pressure pulsation, overruns and has fewer fingers than the second, which is still in a transitional spreading stage. Several important relationships between the drop impact speed, the spray ejection speed of the first ring, and the number of fingers of the second and third rings are presented, based on data acquired during a set of drop impact experiments. Issues related to the traditional use of the R–T instability are also addressed.</P>
Per Magnusson,Anna-Maria Alvarez Holston,Katja Ammon,Guido Ledergerber,Marcus Nilsson,David Schrire,Klaus Nissen,Jonathan Wright 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.2
A series of simulated reactivity-initiated accident (RIA) tests on irradiated fully recrystallized boilingwater reactor Zircaloy-2 cladding has been performed by means of the expansion-due-to-compression(EDC) test method. The EDC method reproduces fuel pelleteclad mechanical interaction (PCMI) conditionsfor the cladding during RIA transients with respect to temperature and loading rates by out-of-pilemechanical testing. The tested materials had a large variation in burnup and hydrogen content (up to907 wppm). The results of the EDC tests showed variation in the PCMI resistance of claddings withsimilar burnup and hydrogen content, making it difficult to clearly identify ductile-to-brittle transitiontemperatures. The EDC-tested samples of the present and previous work were investigated by lightoptical and scanning electron microscopy to study the influence of factors such as azimuthal variation ofthe Zr-hydrides and the presence of hydride rims and radially oriented hydrides. Two main characteristicswere identified in samples with low ductility with respect to hydrogen content and test temperature:hydride rims and radial hydrides at the cladding outer surface. Crack propagation and failuremodes were also studied, showing two general modes of crack propagation depending on distributionand amount of radially oriented hydrides. It was concluded that the PCMI resistance of irradiatedcladding under normal conditions with homogenously distributed circumferential hydrides is high, withgood margin to the RIA failure limits. To further improve safety, focus should be on conditions causingnonfavorable hydride distribution, such as hydride reorientation and formation of hydride blisters at thecladding outer surface.
Lukas Frase,John Peter Doerr,Bernd Feige,Maria Rechenbach,Bernd L. Fiebich,Dieter Riemann,Christoph Nissen,Ulrich Voderholzer 대한정신약물학회 2018 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.16 No.3
Objective: The primary aim of this study was to further characterize the acute effects of amitriptyline (AMI) and escitalopram (ESC) on serum levels of ghrelin, leptin, cortisol and prolactin in healthy humans. Methods: Eleven healthy male participants received a single dose of AMI 75 mg, ESC 10 mg, or placebo (PLA) at 9:00 PM in a double blind, randomized, controlled, repeated measures study separated by one week. Fasting morning serum levels (7:00 AM) of ghrelin, leptin, cortisol and prolactin were assessed. Results: A repeated measures multivariate analysis of variance revealed a significant main effect for the factor condition (AMI, ESC, PLA). Subsequent univariate analyses demonstrated significant condition effects for ghrelin and cortisol. Post-hoc analyses demonstrated a significant reduction of ghrelin levels after AMI in comparison to PLA, and a significant reduction of cortisol levels after AMI in comparison to both ESC and PLA. Other contrasts did not reach statistical significance. Conclusion: Administration of a single dose of AMI, but not of ESC, leads to a significant reduction in morning serum ghrelin and cortisol levels. No effects on leptin and prolactin levels were observed. The differential impact of AMI and ESC on hormones might contribute to different adverse effect profiles of both substances.