Energy deviation study of BEMS at BEPCII Zhang, J.Y.; Cai, X.; Mo, X.H. ...
Nuclear physics. B,
February 2019, 2019-02-00, 2019-02-01, Letnik:
939, Številka:
C
Journal Article
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The beam energy measurement system (BEMS) at the upgraded Beijing Electron-Positron Collider (BEPCII) is designed to provide beam energy value with the relative error at the level of 5×10−5. The ...obvious energy deviation found during J/ψ resonance scan in 2012 leads to great amount of investigations on both BEPCII and BEMS sides. The reasons causing such an unexpected difference are figured out, which include the neutron damage to HPGe detector, the leakage of RF cavity, and the background from Linac. Based on a series of measures, the ψ(3686) line shape scan is designed and performed, the experimental result indicates that BEMS can measure the beam energy with the claimed accuracy. The afterward performance of BEMS is smooth and stable, and BEMS will play a crucial role in the following high accurate experiments.
Photosynthetic characteristics in rice (Oryza sativa L.) leaves were examined after treatment with low temperature (15 deg C) and high irradiance (1,500 mu mol quanta m(-2) s(-1)). Decreases in ...quantum efficiencies in PSII (phi PSII) and PSI (phi PSI) and in the rate of CO2 assimilation were observed with a decrease in the maximal quantum efficiency of PSII (Fv/Fm) by simultaneous measurements of Chl fluorescence, P700(+) absorbance and gas exchange. The decreases in phi PSII were most highly correlated with those in CO2 assimilation. Although the initial (the activity immediately measured upon extraction) and total (the activity following pre-incubation with CO2 and Mg(2+)) activities of ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) decreased slightly, the maximal activity (the activity following treatment with SO4(2-)) of Rubisco remained almost constant. These results indicate that the decrease in CO2 assimilation rate with the decreasing Fv/Fm was not caused by a decrease in Rubisco activity but rather by a decrease in RuBP regeneration capacity which resulted from the decrease in the rate of the linear electron transport. On the other hand, the decrease in (phi PSI was very small and the ratio of phi PSI to phi PSII increased. The de-epoxidation state of xanthophyll cycle pigments also increased. Thus, the cyclic electron transport around PSI occurred in photoinhibited leaves.
In this paper, two Persistent Scatterer Interferometry (PSI) methodologies are compared in order to further understand their potential in the detection of surface deformation. A comparison of these ...two algorithms is a comparison of the two classes of PSI techniques available: coherence estimation based on a temporal model of deformation (represented by DePSI) and coherence estimation based on spatial correlation (represented by StaMPS).
Despite the similarity between the results obtained from the application of the two independent PSI methodologies, significant differences in PS density and distribution were detected, motivating a comparative study between both techniques. We analyze which approach might be more appropriate for studying specific areas/environments, which is helpful in evaluating the benefits that could be derived from an integration of the two methodologies. Several experiments are performed to assess the sensitivity of both PSI approaches to different parameter settings and circumstances. The most significant differences in the processing chain of both procedures are then investigated. We apply both methodologies to the Granada Basin area (southern Spain) and realize that coherence does not improve significantly as function of the methodology applied. If oversampling is implemented in the StaMPS processing chain, the PS density increases so that the density in the urbanized areas is similar to the results provided by DePSI but in all the remaining covers the density is significantly higher. The general results provided by both approaches are very similar in the relative deformations estimated.
► Identification of the main differences between two PSI approaches (DePSI/StaMPS). ► Detailed comparison exploiting the main differences detected. ► PS processing part of each methodology was analyzed and evaluated. ► Evaluation of the potentialities and benefits derived from the integration.
To improve the spatial density of measurement points of persistent-scatterer interferometry, distributed scatterer (DS) should be considered and processed. An important procedure in DS interferometry ...is the phase triangulation (PT). This letter introduces two modified PT algorithms (i.e., equal-weighted PT and coherence-weighted PT) and analyzes the mathematical relations between different published PT methods (i.e., the maximum-likelihood phase estimator, least squares estimator, and eigendecomposition-based phase estimators). The analysis shows that the above five PT methods share very similar mathematical forms with different weight values in the estimation procedure.
The accuracy of orthognathic surgery has improved with three-dimensional virtual planning. The translation of the planning to the surgical result is reported to vary by >2mm. The aim of this ...randomized controlled multi-centre trial was to determine whether the use of splintless patient-specific osteosynthesis can improve the accuracy of maxillary translation. Patients requiring a Le Fort I osteotomy were included in the trial. The intervention group was treated using patient-specific osteosynthesis and the control group with conventional osteosynthesis and splint-based positioning. Fifty-eight patients completed the study protocol, 27 in the patient-specific osteosynthesis group and 31 in the control group. The per protocol median anteroposterior deviation was found to be 1.05mm (interquartile range (IQR) 0.45–2.72mm) in the patient-specific osteosynthesis group and 1.74mm (IQR 1.02–3.02mm) in the control group. The cranial–caudal deviation was 0.87mm (IQR 0.49–1.44mm) and 0.98mm (IQR 0.28–2.10mm), respectively, whereas the left–right translation deviation was 0.46mm (IQR 0.19–0.96mm) in the patient-specific osteosynthesis group and 1.07mm (IQR 0.62–1.55mm) in the control group. The splintless patient-specific osteosynthesis method improves the accuracy of maxillary translations in orthognathic surgery and is clinically relevant for planned anteroposterior translations of more than 3.70mm.
The yeast prion PSI+ is a self-propagating amyloid of the translation termination factor, Sup35p. For known pathogenic prions, such as PSI+, a single protein can form an array of different amyloid ...structures (prion variants) each stably inherited and with differing biological properties. The ribosome-associated chaperones, Ssb1/2p (Hsp70s), and RAC (Zuo1p (Hsp40) and Ssz1p (Hsp70)), enhance de novo protein folding by protecting nascent polypeptide chains from misfolding and maintain translational fidelity by involvement in translation termination. Ssb1/2p and RAC chaperones were previously found to inhibit PSI+ prion generation. We find that most PSI+ variants arising in the absence of each chaperone were cured by restoring normal levels of that protein. PSI+ variants hypersensitive to Ssb1/2p have distinguishable biological properties from those hypersensitive to Zuo1p or Ssz1p. The elevated PSI+ generation frequency in each deletion strain is not due to an altered PIN+, another prion that primes PSI+ generation. PSI+ prion generation/propagation may be inhibited by Ssb1/2/RAC chaperones by ensuring proper folding of nascent Sup35p, thus preventing its joining amyloid fibers. Alternatively, the effect of RAC/Ssb mutations on translation termination and the absence of an effect on the URE3 prion suggest an effect on the mature Sup35p such that it does not readily join amyloid filaments. Ssz1p is degraded in zuo1Δ psi- cells, but not if the cells carry any of several PSI+ variants. Our results imply that prions arise more frequently than had been thought but the cell has evolved exquisite antiprion systems that rapidly eliminate most variants.
Background
Coronal alignment of the tibial component determines functional outcome and survival in total knee arthroplasty (TKA). Innovative techniques for tibial instrumentation have been developed ...to improve accuracy and reduce the rate of outliers.
Methods
In a prospective study, 300 patients were allocated to four different groups using a randomization process (two innovative and two conventional) techniques of tibial instrumentation (conventional: extramedullary, intramedullary; innovative: navigation and patient-specific instrumentation (PSI);
n
= 75 for each group). The aims were to reconstruct the medial proximal tibial angle (MPTA) to 90° and the mechanical tibio-femoral axis (mTFA) to 0°. Both angles were evaluated and compared between all groups three months after the surgery. Patients who presented with a postoperative mTFA > 3° were classified as outliers.
Results
The navigation and intramedullary technique both demonstrated that they were significantly more precise in reconstructing a neutral mTFA and MPTA compared to the other two techniques. The odd’s ratio (OR) for producing outliers was highest for the PSI method (PSI OR = 5.5,
p
< 0.05; extramedullary positioning OR = 3.7,
p
> 0.05; intramedullary positioning OR = 1.7,
p
> 0.05; navigation OR = 0.04,
p
< 0.05). We could only observe significant differences between pre- and postoperative MPTA in the navigation and intramedullary group. The MPTA showed a significant negative correlation with the mTFA in all groups preoperatively and in the extramedullary, intramedullary and PSI postoperatively.
Conclusion
The navigation and intramedullary instrumentation provided the precise positioning of the tibial component. Outliers were most common within the PSI and extramedullary technique. Optimal alignment is dependent on the technique of tibial instrumentation and tibial component positioning determines the accuracy in TKA since mTFA correlated with MPTA pre- and postoperatively.
Drought is one of the most important abiotic stress factors limiting maize production worldwide. The objective of this study was to investigate whether photoprotection of PSII was associated with the ...degree of drought tolerance and yield in three maize hybrids (30Y87, 31R88, P3939). To do this, three maize hybrids were subjected to three cycles of drought, and we measured the activities of photosystem II (PSII) and photosystem I (PSI). In a second field experiment, three maize hybrids were subjected to drought by withholding irrigation, and plant water status, yield and yield attributes were measured. Drought stress decreased leaf water potential (Ψ
) in three maize hybrids, and this reduction was more pronounced in hybrid P3939 (-40%) compared to that of 30Y87 (-30%). Yield and yield attributes of three maize hybrids were adversely affected by drought. The number of kernels and 100-kernel weight was the highest in maize hybrid 30Y87 (-56%, -6%), whereas these were lowest in hybrid P3939 (-88%, -23%). Drought stress reduced the quantum yield of PSII Y(II), photochemical quenching (qP), electron transport rate through PSII ETR(II) and NPQ, except in P3939. Among the components of NPQ, drought increased the Y(NPQ) with concomitant decrease in Y(NO) only in P3939, whereas Y(NO) increased in drought-stressed plants of hybrid 30Y87 and 31R88. However, an increase in cyclic electron flow (CEF) around PSI and Y(NPQ) in P3939 might have protected the photosynthetic machinery but it did not translate in yield. However, drought-stressed plants of 30Y87 might have sufficiently downregulated PSII to match the energy consumption in downstream biochemical processes. Thus, changes in PSII and PSI activity and development of NPQ through CEF are physiological mechanisms to protect the photosynthetic apparatus, but an appropriate balance between these physiological processes is required, without which plant productivity may decline.
To fill the “green absorption gap”, a green absorbing proteorhodopsin was expressed in a PSI-deletion strain (ΔPSI) of Synechocystis sp. PCC6803. Growth-rate measurements, competition experiments and ...physiological characterization of the proteorhodopsin-expressing strains, relative to the ΔPSI control strain, allow us to conclude that proteorhodopsin can enhance the rate of photoheterotrophic growth of ΔPSI Synechocystis strain. The physiological characterization included measurement of the amount of residual glucose in the spent medium and analysis of oxygen uptake- and production rates. To explore the use of solar radiation beyond the PAR region, a red-shifted variant Proteorhodopsin-D212N/F234S was expressed in a retinal-deficient PSI-deletion strain (ΔPSI/ΔSynACO). Via exogenous addition of retinal analogue an infrared absorbing pigment (maximally at 740 nm) was reconstituted in vivo. However, upon illumination with 746 nm light, it did not significantly stimulate the growth (rate) of this mutant. The inability of the proteorhodopsin-expressing ΔPSI strain to grow photoautotrophically is most likely due to a kinetic rather than a thermodynamic limitation of its NADPH-dehydrogenase in NADP+-reduction.
•Proteorhodopsin expression increases growth rate of a ∆PSI Synechocystis strain with at least 16 %.•Proteorhodopsin contributes to proton motive force generation in vivo in Synechocystis.•A transgenic Synechocystis strain has been generated that can absorb infrared light.•‘Reversed electron transfer’ through NDH-1 could not be demonstrated in Synechocystis.
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