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Background: The nitrate regulates soybean nodulation and nitrogen fixation systemically, mainly in inhibiting nodule growth and reducing nodule nitrogenase activity, but the reason for its inhibition is still inconclusive. Methods: The systemic effect of nitrate on nodule structure, function, and carbon distribution in soybean (Glycine max (L.) Merr.) was studied in a dual-root growth system, with both sides inoculated with rhizobia and only one side subjected to nitrate treatment for four days. The non-nodulating side was genetically devoid of the ability to form nodules. Nutrient solutions with nitrogen concentrations of 0, 100, and 200 mg L-1 were applied as KNO3 to the non-nodulating side, while the nodulating side received a nitrogen-free nutrient solution. Carbon partitioning in roots and nodules was monitored using 13C-labelled CO2. Other nodule responses were measured via the estimation of the nitrogenase activity and the microscopic observation of nodule ultrastructure. Results: Elevated concentrations of nitrate applied on the non-nodulating side caused a decrease in the number of bacteroids, fusion of symbiosomes, enlargement of the peribacteroid spaces, and onset of degradation of poly-β-hydroxybutyrate granules, which is a form of carbon storage in bacteroids. These microscopic observations were associated with a strong decrease in the nitrogenase activity of nodules. Furthermore, our data demonstrate that the assimilated carbon is more likely to be allocated to the non-nodulating roots, as follows from the competition for carbon between the symbiotic and non-symbiotic sides of the dual-root system. Conclusion: We propose that there is no carbon competition between roots and nodules when they are indirectly supplied with nitrate, and that the reduction of carbon fluxes to nodules and roots on the nodulating side is the mechanism by which the plant systemically suppresses nodulation under nitrogen-replete conditions. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are known to improve plant stress tolerance by regulating proline accumulation, and nitric oxide (NO) plays an important signaling role in proline metabolism. Environmental nitrogen (N) affects AMF colonization and its contribution to host plants resistance to stress conditions. However, the relationship between proline metabolism and NO in mycorrhizal rice and the effect of N application on symbiont proline metabolism under low temperature have not been established. Pot culture experiments with different temperature, N and exogenous NO donor treatments were conducted with non-mycorrhizal and mycorrhizal rice. The results showed that AMF enhanced rice proline accumulation under lowtemperature stress and decreased glutamate (Glu) and ornithine (Orn) concentrations significantly. In comparison with non-mycorrhizal rice, AMF colonization significantly decreased the Glu concentration, but had little effect on the Orn concentration under low-temperature stress, accompanied by increasing expression of OsP5CS2, OsOAT and OsProDH1. Exogenous application of NO increased proline concentration both under normal and low temperature, which exhibited a higher increase in mycorrhizal rice. NO also triggered the expression of key genes in the Glu and Orn pathways of proline synthesis as well as proline degradation. Higher N application decreased the AMF colonization, and AMF showed greater promotion of proline metabolism at low N levels under low temperature stress by regulating the Glu synthetic pathway. Meanwhile, AMF increased rice nitrate reductase (NR) and nitric oxide synthase (NOS) activities and then enhanced NO accumulation under low N levels. Consequently, it could be hypothesized that one of the mechanisms by which AMF improves plant resistance to low-temperature stress is the accumulation of proline via enhancement of the Glu and Orn synthetic pathways, with the involvement of the signaling molecule NO. However, the contribution of AMF to rice proline accumulation under low-temperature stress was attenuated by high N application. [ABSTRACT FROM AUTHOR]

Purposes: Preimplant diagnostic magnetic resonance imaging is the gold standard for image‐guided tandem‐and‐ovoids (T&O) brachytherapy for cervical cancer. However, high dose rate brachytherapy planning is typically done on postimplant CT‐based high‐risk clinical target volume (HR‐CTVCT) because the transfer of preimplant Magnetic resonance (MR)‐based HR‐CTV (HR‐CTVMR) to the postimplant planning CT is difficult due to anatomical changes caused by applicator insertion, vaginal packing, and the filling status of the bladder and rectum. This study aims to train a dual‐path convolutional neural network (CNN) for automatic segmentation of HR‐CTVCT on postimplant planning CT with guidance from preimplant diagnostic MR. Methods: Preimplant T2‐weighted MR and postimplant CT images for 65 (48 for training, eight for validation, and nine for testing) patients were retrospectively solicited from our institutional database. MR was aligned to the corresponding CT using rigid registration. HR‐CTVCT and HR‐CTVMR were manually contoured on CT and MR by an experienced radiation oncologist. All images were then resampled to a spatial resolution of 0.5 × 0.5 × 1.25 mm. A dual‐path 3D asymmetric CNN architecture with two encoding paths was built to extract CT and MR image features. The MR was masked by HR‐CTVMR contour while the entire CT volume was included. The network put an asymmetric weighting of 18:6 for CT: MR. Voxel‐based dice similarity coefficient (DSCV), sensitivity, precision, and 95% Hausdorff distance (95‐HD) were used to evaluate model performance. Cross‐validation was performed to assess model stability. The study cohort was divided into a small tumor group (<20 cc), medium tumor group (20–40 cc), and large tumor group (>40 cc) based on the HR‐CTVCT for model evaluation. Single‐path CNN models were trained with the same parameters as those in dual‐path models. Results: For this patient cohort, the dual‐path CNN model improved each of our objective findings, including DSCV, sensitivity, and precision, with an average improvement of 8%, 7%, and 12%, respectively. The 95‐HD was improved by an average of 1.65 mm compared to the single‐path model with only CT images as input. In addition, the area under the curve for different networks was 0.86 (dual‐path with CT and MR) and 0.80 (single‐path with CT), respectively. The dual‐path CNN model with asymmetric weighting achieved the best performance with DSCV of 0.65 ± 0.03 (0.61–0.70), 0.79 ± 0.02 (0.74–0.85), and 0.75 ± 0.04 (0.68–0.79) for small, medium, and large group. 95‐HD were 7.34 (5.35–10.45) mm, 5.48 (3.21–8.43) mm, and 6.21 (5.34–9.32) mm for the three size groups, respectively. Conclusions: An asymmetric CNN model with two encoding paths from preimplant MR (masked by HR‐CTVMR) and postimplant CT images was successfully developed for automatic segmentation of HR‐CTVCT for T&O brachytherapy patients. [ABSTRACT FROM AUTHOR]

Although Fraxinellone (Frax) isolated from Dictamnus albus L. possessed excellent anti-hepatic fibrosis activity, oral administration of Frax suffered from the inefficient therapeutic outcome in vivo due to negligible oral absorption. At present, the oral formulation of Frax is rarely exploited. For rational formulation design, we evaluated preabsorption risks of Frax and found that Frax was rather stable while poorly dissolved in the gastrointestinal tract (78.88 lg/mL), which predominantly limited its oral absorption. Further solubility test revealed the outstanding capacity of cyclodextrin derivatives (CDs) to solubilize Frax (6.8-12.8mg/mL). This led us to study the inclusion complexes of Frax with a series of CDs and holistically explore their drug delivery performance. Characterization techniques involving ¹H-NMR, FT-IR, DSC, PXRD, and molecular docking confirmed the most stable binding interactions when Frax complexed with 6-O-α-D-maltosyl-β-cyclodextrin (G2-β-CD-Frax). Notably, G2-β-CD-Frax exhibited the highest solubilizing capacity, fast dissolution rate, and superior Caco-2 cell internalization with no obvious toxicity. Pharmacokinetic studies demonstrated markedly higher oral bioavailability of G2-β-CD-Frax (5.8-fold that of free drug) than other Frax-CDs. Further, long-term administration of G2- β-CD-Frax (5 mg/kg) efficiently inhibited CCl4-induced hepatic fibrosis in the mouse without inducing any toxicity. Our results will inspire the continued advancement of optimal oral Frax formulations for anti-fibrotic therapy. [ABSTRACT FROM AUTHOR]

Detection of brain metastases is a paramount task in cancer management due both to the number of high-risk patients and the difficulty of achieving consistent detection. In this study, we aim to improve the accuracy of automated brain metastasis (BM) detection methods using a novel asymmetric UNet (asym-UNet) architecture. An end-to-end asymmetric 3D-UNet architecture, with two down-sampling arms and one up-sampling arm, was constructed to capture the imaging features. The two down-sampling arms were trained using two different kernels (3 × 3 × 3 and 1 × 1 × 3, respectively) with the kernel (1 × 1 × 3) dominating the learning. As a comparison, vanilla single 3D UNets were trained with different kernels and evaluated using the same datasets. Voxel-based Dice similarity coefficient (DSCv), sensitivity (Sv), precision (Pv), BM-based sensitivity (SBM), and false detection rate (FBM) were used to evaluate model performance. Contrast-enhanced T1 MR images from 195 patients with a total of 1034 BMs were solicited from our institutional stereotactic radiosurgery database. The patient cohort was split into training (160 patients, 809 lesions), validation (20 patients, 136 lesions), and testing (15 patients, 89 lesions) datasets. The lesions in the testing dataset were further divided into two subgroups based on the diameters (small S = 1–10 mm, large L = 11–26 mm). In the testing dataset, there were 72 and 17 BMs in the S and L sub-groups, respectively. Among all trained networks, asym-UNet achieved the highest DSCv of 0.84 and lowest FBM of 0.24. Although vanilla 3D-UNet with a single 1 × 1 × 3 kernel achieved the highest sensitivities for the S group, it resulted in the lowest precision and highest false detection rate. Asym-UNet was shown to balance sensitivity and false detection rate as well as keep the segmentation accuracy high. The novel asym-UNet segmentation network showed overall competitive segmentation performance and more pronounced improvement in hard-to-detect small BMs comparing to the vanilla single 3D UNet. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to investigate x‐ray beam profiles at various water depths to characterize the two‐dimensional x‐ray dose distribution, allowing for off‐axis and out‐of‐field radiation dose estimation for a wide range of x‐ray beam spectra commonly encountered in fluoroscopically guided interventional procedures. Methods: A Siemens Artis interventional fluoroscope was operated in a service mode to generate a continuous x‐ray beam at fixed x‐ray beam spectra, defined by their kVp and the thickness of additional copper filtration. A PTW scanning water tank with a diode detector was used to measure the x‐ray beam profiles at several depths in water at various fields of view and x‐ray beam spectra, both parallel and perpendicular to the anode‐cathode axis direction. Results: X‐ray beam profiles, including out‐of‐field tails, were characterized for a wide range of beam qualities. The anode heel effect was pronounced even at depth, resulting in large dose variations across the x‐ray field; this effect was even more definite at large fields of view, at higher kVps, and in the absence of additional copper filtration. Conclusions: This study investigated and characterized 2D radiation dose deposition in water from x‐ray beam spectra commonly used by modern fluoroscopes in interventional procedures. This knowledge can be applied to manual dosimetry calculations or can be used to refine the accuracy of automated dose mapping tools or Monte Carlo simulations of the radiation dose to soft tissue within the x‐ray field and to tissue adjacent to the primary beam. Additionally, this study illustrates a substantial reduction of the anode heel effect by using moderate amounts of additional copper filtration to harden the x‐ray beam spectrum. [ABSTRACT FROM AUTHOR]

Abstract: Purposes: The aim of this study was to evaluate a dual marker‐based and soft‐tissue based image guidance for inter‐fractional corrections in stereotactic body radiotherapy (SBRT) of prostate cancer. Methods/Materials: We reviewed 18 patients treated with SBRT for prostate cancer. An endorectal balloon was inserted at simulation and each treatment. Planning margins were 3 mm/0 mm posteriorly. Prior to each treatment, a dual image guidance protocol was applied to align three makers using stereoscopic x ray images and then to the soft tissue using kilo‐voltage cone beam CT (kV‐CBCT). After treatment, prostate (CTV), rectal wall, and bladder were delineated on each kV‐CBCT, and delivered dose was recalculated. Dosimetric endpoints were analyzed, including V36.25 Gy for prostate, and D0.03 cc for bladder and rectal wall. Results: Following initial marker alignment, additional translational shifts were applied to 22 of 84 fractions after kV‐CBCT. Among the 22 fractions, ten fractions exceeded 3 mm shifts in any direction, including one in the left‐right direction, four in the superior‐inferior direction, and five in the anterior‐posterior direction. With and without the additional kV‐CBCT shifts, the average V36.25 Gy of the prostate for the 22 fractions was 97.6 ± 2.6% with the kV x ray image alone, and was 98.1 ± 2.4% after applying the additional kV‐CBCT shifts. The improvement was borderline statistical significance using Wilcoxon signed‐rank test (P = 0.007). D0.03 cc was 45.8 ± 6.3 Gy vs. 45.1 ± 4.9 Gy for the rectal wall; and 49.5 ± 8.6 Gy vs. 49.3 ± 7.9 Gy for the bladder before and after applying kV‐CBCT shifts. Conclusions: Marker‐based alignment alone is not sufficient. Additional adjustments are needed for some patients based kV‐CBCT. [ABSTRACT FROM AUTHOR]

Purpose In this investigation, we sought to characterize X-ray beam qualities and quantitate percent depth dose (PDD) curves for fluoroscopic X-ray beams incorporating added copper (Cu) filtration, such as those commonly used in fluoroscopically guided interventions (FGI). The intended application of this research is for dosimetry in soft tissue from FGI procedures using these data. Methods All measurements in this study were acquired on a Siemens (Erlangen, Germany) Artis zeego fluoroscope. X-ray beam characteristics of first half-value layer (HVL), second HVL, homogeneity coefficients (HCs), backscatter factors (BSFs) and kVp accuracy and precision were determined to characterize the X-ray beams used for the PDD measurements. A scanning water tank was used to measure PDD curves for 60, 80, 100, and 120 kVp X-ray beams with Cu filtration thicknesses of 0.0, 0.1, 0.3, 0.6, and 0.9 mm at 11 cm, 22 cm, and 42 cm nominal fields of view, in water depths of 0 to 150 mm. Results X-ray beam characteristics of first HVLs and HCs differed from previous published research of fluoroscopic X-ray beam qualities without Cu filtration. PDDs for 60, 80, 100, and 120 kVp with 0 mm of Cu filtration were comparable to previous published research, accounting for differences in fluoroscopes, geometric orientation, type of ionization chamber, X-ray beam quality, and the water tank used for data collection. PDDs and X-ray beam characteristics for beam qualities with Cu filtration are presented, which have not been previously reported. Conclusions The data sets of X-ray beam characteristics and PDDs presented in this study can be used to estimate organ or soft tissue doses at depth involving similar beam qualities or to compare with mathematical models. [ABSTRACT FROM AUTHOR]

Poor management is the main reason for high N losses and reduced yield in rice production. Improved crop management in northeastern China is becoming increasingly important due to economic pressures in southern and central China along with rising temperatures in the Northeast, which have led to a major shift in rice (Oryza sativa L.) production to this region. Here, we examine the opportunities for improving the yield and nitrogen use efficiency (NUE) of irrigated rice in northeastern China by optimizing nutrients and increasing the transplanting density. In 2009 to 2011, field experiments were conducted to compare optimized nutrient management (ONM) and optimized crop management treatments (OCM) with the farmers' crop management (FCM) and no N treatment (control). Compared with the FCM, the ONM and OCM treatments significantly increased average grain yield by respective averages of 9 and 17%. These yield gains resulted from a combination of increases in grains per panicle and panicles per unit area. Compared with the FCM treatment, agronomic efficiency (AEN), recovery efficiency of applied nitrogen (REN) and partial factor productivity of applied nitrogen (PFPN) were enhanced by an average of 120, 116, and 67% across the ONM and OCM treatments in the 3-yr study period, respectively. It is clear that high yields combined with high N use efficiency are possible in northeastern China by appropriately increasing rice transplanting density and optimizing nutrient management. [ABSTRACT FROM AUTHOR]

We investigated morphological changes of a released carpal tunnel in response to variations of carpal tunnel pressure. Pressure within the carpal tunnel is known to be elevated in patients with carpal tunnel syndrome and dependent on wrist posture. Previously, increased carpal tunnel pressure was shown to affect the morphology of the carpal tunnel with an intact transverse carpal ligament (TCL). However, the pressure-morphology relationship of the carpal tunnel after release of the TCL has not been investigated. Carpal tunnel release (CTR) was performed endoscopically on cadaveric hands and the carpal tunnel pressure was dynamically increased from 10 to 120 mmHg. Simultaneously, carpal tunnel cross-sectional images were captured by an ultrasound system, and pressure measurements were recorded by a pressure transducer. Carpal tunnel pressure significantly affected carpal arch area ( p < 0.001), with an increase of >62 mm2 at 120 mmHg. Carpal arch height, length, and width also significantly changed with carpal tunnel pressure ( p < 0.05). As carpal tunnel pressure increased, carpal arch height and length increased, but the carpal arch width decreased. Analyses of the pressure-morphology relationship for a released carpal tunnel revealed a nine times greater compliance than that previously reported for a carpal tunnel with an intact TCL. This change of structural properties as a result of transecting the TCL helps explain the reduction of carpal tunnel pressure and relief of symptoms for patients after CTR surgery. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 616-620, 2013 [ABSTRACT FROM AUTHOR]

We report here that the efficiency of the click chemistry between the terminal azide and alkyne groups of different polymer chains could be drastically increased with the addition of an optimum amount of water into a reaction system. That is, the efficiency was only slightly promoted by the addition of a small amount of water into the reaction mixture. However, the reaction efficiency was increased dramatically near the water volume fraction to lead the reaction mixture into nano-sized phase separation. Further increasing in water content caused the polymer(s) to undergo macroscopic phase separation and the click reaction efficiency was decreased once again. The enhanced efficiency of click coupling reaction including conversion and rate was also demonstrated via in-situ 1H-NMR. The reaction kinetics as well as reaction rate constant for these reaction system with typical water content were also evaluated. This finding on enhanced click reaction is of practical value, because click reactions in polymer synthesis are generally more difficult to be carried out and proceed relative slowly at low yield in most case because of the strong steric hindrance effect from "large and long" polymer chains, as compared to "click" reactions which are employed for preparation of the low molecular weight organic compounds. [ABSTRACT FROM AUTHOR]

The transverse carpal ligament (TCL) forms the volar boundary of the carpal tunnel and may provide mechanical constraint to the median nerve, leading to carpal tunnel syndrome. Therefore, the mechanical properties of the TCL are essential to better understand the etiology of carpal tunnel syndrome. The purpose of this study was to investigate the in vivo TCL stiffness using acoustic radiation force impulse (ARFI) imaging. The shear wave velocity (SWV) of the TCL was measured using Virtual Touch IQTM software in 15 healthy, male subjects. The skin and the thenar muscles were also examined as reference tissues. In addition, the effects of measurement location and ultrasound transducer compression on the SWV were studied. The SWV of the TCL was dependent on the tissue location, with greater SWV values within the muscle-attached region than those outside of the muscle-attached region. The SWV of the TCL was significantly smaller without compression (5.21 ± 1.08 m/s) than with compression (6.62 ± 1.18 m/s). The SWV measurements of the skin and the thenar muscles were also affected by transducer compression, but to different extents than the SWV of the TCL. Therefore to standardize the ARFI imaging procedure, it is recommended that a layer of ultrasound gel be maintained to minimize the effects of tissue compression. This study demonstrated the feasibility of ARFI imaging for assessing the stiffness characteristics of the TCL in vivo, which has the potential to identify pathomechanical changes of the tissue. [ABSTRACT FROM AUTHOR]