Application of chemical fertilizers, especially nitrogen (N), to crops has increased dramatically in the last half century and therefore developing crop varieties with improved N use efficiency (NUE) is urgent for sustainable agriculture. N utilization procedures generally can be divided into uptake, transport, and assimilation. Transporters for nitrate or ammonium acquisition and enzymes for assimilation are among the essential components determining NUE, and many transcription factors also play a pivotal role in regulating N use-associated genes, thereby contributing to NUE. Although some efforts in improving NUE have been made in various plants, the regulatory mechanisms underlying NUE are still elusive, and NUE improvement in crop breeding is very limited. In this review, the crucial components involved in N utilization and the candidates with the potential for NUE improvement in dicot Arabidopsis and monocot rice are summarized. In addition, strategies based on new techniques which can be used for dissecting regulatory mechanisms of NUE and also the possible ways in which NUE can be improved in crops are discussed.

In this paper, we propose an innovative approach to the segmentation of tubular structures. This approach combines all of the benefits of minimal path techniques such as global minimizers, fast computation, and powerful incorporation of user input, while also having the capability to represent and detect vessel surfaces directly which so far has been a feature restricted to active contour and surface techniques. The key is to represent the trajectory of a tubular structure not as a 3-D curve but to go up a dimension and represent the entire structure as a 4-D curve. Then we are able to fully exploit minimal path techniques to obtain global minimizing trajectories between two user supplied endpoints in order to reconstruct tubular structures from noisy or low contrast 3-D data without the sensitivity to local minima inherent in most active surface techniques. In contrast to standard purely spatial 3-D minimal path techniques, however, we are able to represent a full tubular surface rather than just a curve which runs through its interior. Our representation also yields a natural notion of a tube's "central curve." We demonstrate and validate the utility of this approach on magnetic resonance (MR) angiography and computed tomography (CT) images of coronary arteries.

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Objective: Interstitial fluid flow through vascular adventitia has been disclosed recently. However, its kinetic pattern was unclear. Methods and Results:We used histological and topographical identifications to observe ISF flow along venous vessels in rabbits. By MRI in alive subjects, the inherent ISF flow pathways in legs, abdomen and thorax were enhanced by paramagnetic contrast from ankle dermis. By fluorescence stereomicroscopy and layer-by-layer dissection after the rabbits were sacrificed, the perivascular and adventitial connective tissues (PACT) along the saphenous veins and inferior vena cava were found to be stained by sodium fluorescein from ankle dermis, which coincided with the findings by MRI.By confocal microscopy and histological analysis, the stained PACT pathways were verified to be the fibrous connective tissues and consisted of longitudinally assembled fibers. By usages of nanoparticles and surfactants, a PACT pathway was found to be accessible for a nanoparticle under 100nm and contain two parts: a tunica channel part and an absorptive part. In real-time observations, the calculated velocity of a continuous ISF flow along fibers of a PACT pathway was 3.6-15.6 mm/sec. Conclusion:These data further revealed more kinetic features of a continuous ISF flow along vascular vessel. A multiscale, multilayer, and multiform "interstitial/interfacial fluid flow" throughout perivascular and adventitial connective tissues was suggested as one of kinetic and dynamic mechanisms for ISF flow, which might be another principal fluid dynamic pattern besides convective/vascular and diffusive transport in biological system.

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Objective: Interstitial fluid in extracellular matrices may not be totally fixed but partially flow through long-distance oriented fibrous connective tissues via physical mechanisms. We hypothesized there is a long-distance interstitial fluid transport network beyond vascular circulations. Materials and methods:We first used 20 volunteers to determine hypodermic entrant points to visualize long-distance extravascular pathway by MRI. We then investigated the extravascular pathways initiating from the point of thumb in cadavers by chest compressor. The distributions and structures of long-distance pathways from extremity ending to associated visceral structures were identified.Results: Using fluorescent tracer, the pathways from right thumb to right atrium wall near chest were visualized in seven of 10 subjects. The cutaneous pathways were found in dermic, hypodermic and fascial tissues of hand and forearm. The perivascular pathways were along the veins of arm, axillary sheath, superior vena cava and into the superficial tissues on right atrium. Histological and micro-CT data showed these pathways were neither blood nor lymphatic vessels but long-distance oriented fibrous matrices, which contained the longitudinally assembled micro-scale fibres consistently from thumb to superficial tissues on right atrium.

B cells that express the isotype-switched IgG-B cell receptor (IgG-BCR) are one of the driving forces for antibody memory. To allow for a rapid memory IgG antibody response, IgG-BCR evolved into a highly effective signalling machine. Here, we report that the positively charged cytoplasmic domain of mIgG (mIgG-tail) specifically interacts with negatively charged acidic phospholipids. The key immunoglobulin tail tyrosine (ITT) in mIgG-tail is thus sequestered in the membrane hydrophobic core in quiescent B cells. Pre-disruption of such interaction leads to excessive recruitment of BCRs and inflated BCR signalling upon antigen stimulation, resulting in hyperproliferation of primary B cells. Physiologically, membrane-sequestered mIgG-tail can be released by antigen engagement or Ca2+ mobilization in the initiation of B cell activation. Our studies suggest a novel regulatory mechanism for how dynamic association of mIgG-tail with acidic phospholipids governs the enhanced activation of IgG-BCR.

Information recording and encryption/decryption functions are essential due to the prevalence of counterfeiting activities and information leakage in the current age. However, the development of high-resolution information recording and multistage information protection systems to achieve high data security levels, such as self-erasing encrypted data and time-controlled data handling, remains limited. Herein, inspired by the information-recording structure of paper, a multiresponsive nanofiber-reinforced poly(N-isopropylacrylamide) (PNIPAM) hydrogel (NCPN hydrogel) with improved mechanical properties, solvent-induced high-resolution reversible information recording, self-encryption, and multi-decryption capabilities, is proposed. Due to the unique hydrophilic and hydrophobic structures of the hydrogel matrix, ethanol and other polar analogs can be applied as special inks to record information by changing the lower critical solution temperature to achieve the repeatable transmittance variation. The recorded information can be erased via water wiping or ethanol volatilization. Additionally, self-encryption can be achieved and adjusted based on the ethanol volatilization time and concentration difference, and confidential information can be further decrypted in a water environment or under a thermal stimulus. Furthermore, several stable, repeatable, and fast-response hydrogel-based information-recognition systems are designed and investigated. Therefore, the designed hydrogel-based informational platform provides a universal information-handling system allowing for the reversible recording of information, with self-encryption and multidecryption capabilities.