Membralin is required for maize development and defines a branch of the endoplasmic reticulum-associated degradation pathway in plants.

Endoplasmic reticulum (ER)-associated degradation (ERAD) plays key roles in controlling protein levels and quality in eukaryotes. The Ring Finger Protein 185 (RNF185)/membralin ubiquitin ligase complex was recently identified as a branch in mammals and is essential for neuronal function, but its function in plant development is unknown. Here, we report the map-based cloning and characterization of Narrow Leaf and Dwarfism 1 (NLD1), which encodes the ER membrane-localized protein membralin and specifically interacts with maize homologs of RNF185 and related components. The nld1 mutant shows defective leaf and root development due to reduced cell number. The defects of nld1 were largely restored by expressing membralin genes from Arabidopsis thaliana and mice, highlighting the conserved roles of membralin proteins in animals and plants. The excessive accumulation of ß-hydroxy ß-methylglutaryl-CoA reductase in nld1 indicates that the enzyme is a membralin-mediated ERAD target. The activation of bZIP60 mRNA splicing-related unfolded protein response signaling and marker gene expression in nld1, as well as DNA fragment and cell viability assays, indicate that membralin deficiency induces ER stress and cell death in maize, thereby affecting organogenesis. Our findings uncover the conserved, indispensable role of the membralin-mediated branch of the ERAD pathway in plants. In addition, ZmNLD1 contributes to plant architecture in a dose-dependent manner, which can serve as a potential target for genetic engineering to shape ideal plant architecture, thereby enhancing high-density maize yields.

Development of a large-field streak tube for underwater imaging lidar.

Streak tube imaging lidar (STIL) can obtain 4-D images of a target, and its performance is mainly determined by the streak tube sensor. To obtain a large field of view, we developed a streak tube with a photocathode length as large as 35.3 mm, which is larger than the commonly used ST-HDR (30 mm). At the same time, the temporal resolution and dynamic spatial resolution are 60 ps and 12 lp/mm, which are very suitable to obtain accurate target coordinates for 4-D imaging. In addition, the streak tube has a high detection sensitivity of 46 mA/W at 500 nm and, hence, prospects in remote imaging. To test the performance of the streak tube, an underwater STIL experiment was conducted. Echo signal processing was performed by means of a bandpass filter and a matched filter, and then the peak detection algorithm was used to reconstruct the image. The results indicate that a spatial resolution better than 9 mm is achieved in the limpid water with a depth of 20 m, and a range accuracy of 1 cm is achieved in the turbid water with a depth of 10 m. Such a performance suggests that the large-field streak tube is of great potential for underwater target imaging and other remote imaging applications.

ZmSKS13, a cupredoxin domain-containing protein, is required for maize kernel development via modulation of redox homeostasis.

The SKU5 similar (SKS) genes encode a family of multi-copper-oxidase-like proteins with cupredoxin domains similar to those in laccase and ascorbate oxidase. Although SKS proteins are known to function in root growth and cotyledon vascular patterning in Arabidopsis, their role in plant reproductive processes is poorly understood. Here, we identified a seed mutant of maize (Zea mays), generated by ethyl methane sulfonate (EMS) mutagenesis, that we designated defective kernel-zk1 (dek-zk1). The mutant produced small, shriveled kernels with an aberrant basal endosperm transfer layer (BETL) and placento-chalazal (PC) layer and irregular starch granules. Map-based cloning revealed that Dek-zk1 encodes an SKU5 similar 13 (GenBank: ONM36900.1), so it was named ZmSKS13. ZmSKS13 comprises a paralogous pair with Zm00001d012524, but the transcript abundance of ZmSKS13 in developing kernels is 15 times higher than that of Zm00001d012524, resulting in dek-zk1 mutation conveying a distinct kernel phenotype. ZmSKS13 loss of function led to overaccumulation of reactive oxygen species (ROS) and severe DNA damage in the nucellus and BETL and PC layer cells, and exogenous antioxidants significantly alleviated the defects of the mutant kernels. Our results thus demonstrate that ZmSKS13 is a novel regulator that plays a crucial role in kernel development in maize through the modulation of ROS homeostasis.

Evaluation of microvascular permeability of skeletal muscle and texture analysis based on DCE-MRI in alloxan-induced diabetic rabbits.

OBJECTIVES: To estimate the microvascular permeability and perfusion of skeletal muscle by using quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and explore the feasibility of using texture analysis (TA) to evaluate subtle structural changes of diabetic muscles. METHODS: Twenty-four rabbits were randomly divided into diabetic (n = 14) and control (n = 10) groups, and underwent axial DCE-MRI of the multifidus muscle (0, 4, 8, 12, and 16 weeks after alloxan injection). The pharmacokinetic model was used to calculate the permeability parameters; texture parameters were extracted from volume transfer constant (Ktrans) map. The two-sample t test/Mann-Whitney U test, repeated measures analysis of variance/Friedman test, and Pearson correlations were used for data analysis. RESULTS: In the diabetic group, Ktrans and rate constant (Kep) increased significantly at week 8 and then showed a decreasing trend. Extravascular extracellular space volume fraction (Ve) increased and plasma volume fraction (Vp) decreased significantly from the 8th week. Skewness began to decrease at the 4th week. Median Ktrans and entropy increased significantly, while inverse difference moment decreased from the 8th week. Energy decreased while contrast increased only at week 8. Muscle fibre cross-sectional area was negatively correlated with Ve. The capillary-to-fibre ratio was positively correlated with Vp (p < 0.05, all). CONCLUSIONS: Quantitative DCE-MRI can be used to evaluate microvascular permeability and perfusion in diabetic skeletal muscle at an early stage; TA based on Ktrans map can identify microarchitectural modifications in diabetic muscles. KEY POINTS: • Four quantitative parameters of DCE-MRI can be used to evaluate microvascular permeability and perfusion of skeletal muscle in diabetic models at early stages. • Texture analysis based on Ktrans map can identify subtle structural changes in diabetic muscles.

SH1-dependent maize seed development and starch synthesis via modulating carbohydrate flow and osmotic potential balance.

BACKGROUND: As the main form of photoassimilates transported from vegetative tissues to the reproductive organs, sucrose and its degradation products are crucial for cell fate determination and development of maize kernels. Despite the relevance of sucrose synthase SH1 (shrunken 1)-mediated release of hexoses for kernel development, the underlying physiological and molecular mechanisms are not yet well understood in maize (Zea mays). RESULTS: Here, we identified a new allelic mutant of SH1 generated by EMS mutagenesis, designated as sh1*. The mutation of SH1 caused more than 90% loss of sucrose synthase activity in sh1* endosperm, which resulted in a significant reduction in starch contents while a dramatic increase in soluble sugars. As a result, an extremely high osmolality in endosperm cells of sh1* was generated, which caused kernel swelling and affected the seed development. Quantitative measurement of phosphorylated sugars showed that Glc-1-P in endosperm of sh1* (17 µg g- 1 FW) was only 5.2% of that of wild-type (326 µg g- 1 FW). As a direct source of starch synthesis, the decrease of Glc-1-P may cause a significant reduction in carbohydrates that flow to starch synthesis, ultimately contributing to the defects in starch granule development and reduction of starch content. CONCLUSIONS: Our results demonstrated that SH1-mediated sucrose degradation is critical for maize kernel development and starch synthesis by regulating the flow of carbohydrates and maintaining the balance of osmotic potential.

Isolation and characterization of a 295-bp strong promoter of maize high-affinity phosphate transporter gene ZmPht1; 5 in transgenic Nicotiana benthamiana and Zea mays.

MAIN CONCLUSION: The small 295-bp ZmPht1; 5 promoter is sufficient to drive high-intensity expression of target genes, especially under phosphate deprivation conditions, and is therefore useful for crop improvement via transgenic techniques. Phosphate (Pi) deficiency has become a major challenge and limiting factor in world agricultural production. Manipulating the gene expression using appropriate promoters to improve the Pi absorption and utilization efficiency of crops could reduce the requirement for Pi fertilizers. In the study, a 295-bp strong promoter (M2P-7) of maize high-affinity phosphate transporter ZmPht1; 5 was isolated and functionally validated in transgenic Nicotiana benthamiana and maize by analyzing the ZmPht1; 5 promoter (M2P-1) and its 5' truncated variants (M2P-2 ~ M2P-8) in different sizes under normal and Pi-deprivation conditions. The M2P-7 displayed the highest promoter activities among 5' truncated fragments in all tested tissues of transgenic Nicotiana benthamiana at different development stages, which was 1.5 and 3 times higher than the well-used CaMV35S promoter under normal and Pi-deprivation conditions, respectively. In maize, the M2P-7 promoter activity was comparable to the maize ubiquitin1 promoter widely used in monocots under normal condition, which was about 1.3 times that of the ubiquitin1 promoter under Pi-deprivation environments. Moreover, the M2P-7 fragment is only 295 bp in length, thus reducing the construct size, and is therefore beneficial for genetic transformation. Thus, the small promoter M2P-7 of plant origin could be of great use for monocotyledonous and dicotyledonous crop improvement via transgenic techniques based on its promoter activities, expression patterns and small size.

Intracranial peak pressure as a predictor for perioperative mortality after spontaneous intracerebral hemorrhage evacuation and decompressive craniectomy.

BACKGROUND: An optimal intracranial pressure (ICP) management target is not well defined in patients with spontaneous intracerebral hemorrhage. The aim of this study was to explore the association between perioperative ICP monitoring parameters and mortality of patients with spontaneous intracerebral hematoma undergoing emergency hematoma removal and decompressive craniectomy (DC), to provide evidence for a target-oriented ICP management. METHODS: The clinical and radiological features of 176 consecutive patients with spontaneous intracerebral hemorrhage that underwent emergent hematoma evacuation and DC were reviewed. The Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS) scores were assessed 2 weeks after surgery. Multivariate logistic regression analysis was performed to identify predictors for perioperative death. RESULTS: Forty-four cases (25.0%) were assigned to the ICP group. In patients with an ICP monitor, the median peak ICP value was 25.5 mmHg; 50% of them had a peak ICP value of more than 25 mmHg. The median duration of ICP > 25 mmHg was 2 days. Without a target-specific ICP management, the mortality at 2 weeks after surgery was similar between patients with or without an ICP monitor (27.3% versus 18.2%, p = 0.20). In multivariable analysis, the peak ICP value (OR 1.11, 95% CI 1.004-1.234, p = 0.04) was significantly associated with perioperative death in the ICP group. The area under ROC curve of peak ICP value was 0.78 (95%CI 0.62-0.94) for predicting mortality, with a cut-off value of 31 mmHg. CONCLUSION: Compared with a persistent hyperintracranial pressure, a high ICP peak value might provide a better prediction for the mortality of patients with spontaneous intracerebral hemorrhage evacuation and DC, suggesting a tailored ICP management protocol to decrease ICP peak value.

Design of multi-frequency point, high-isolation switches for micro-channel plate data acquisition.

In order to replace the phosphor screen of a proximity-gated x-ray framing camera with a readout circuit using a time-interleaved structure, this paper carries out the design of a high-isolation RF switch. In this paper, a Metal-Oxide-Semiconductor Field Effect Tube (MOSFET) switching circuit is designed to achieve high isolation and low insertion loss at 0.5-3 GHz. This solves the problem that the switching circuit cannot be turned off properly due to the parasitic capacitance of MOSFETs in the process of RF signal transmission, resulting in signal feedthrough. It also ensures that the input signal can be transmitted to the output intact when the switching circuit is turned on. High isolation is achieved by using parallel resonance to increase the voltage division and series resonance to leak the current. The switch achieves 76 dB isolation and 0.07 dB insertion loss at 1 GHz frequency. Isolation is increased by adding parallel branches near the 2 and 3 GHz frequency points, achieving greater than 33 dB isolation from 0.5 to 3 GHz.

Three-dimensional reconstruction of laser-imploded targets from simulated pinhole images.

This paper proposes an integral method to achieve a more accurate weighting matrix that makes very positive contributions to the image reconstruction in inertial confinement fusion research. Standard algebraic reconstruction techniques with a positivity constraint included are utilized. The final normalized mean-square error between the simulated and reconstructed projection images is 0.000365%, which is a nearly perfect result, indicating that the weighting matrix is very important. Compared with the error between the simulated and reconstructed phantoms, which is 2.35%, it seems that the improvement of the accuracy of the projection image does not mean the improvement of the phantom. The proposed method can reconstruct a simulated laser-imploded target consisting of 100×100×100 voxels.

[Research on the method of transient spectrum detection based on array CCD].

Based on the characteristic of high speed line scanning for CCD in transient spectrum detection, a method of transient spectrum detection with array CCD is presented. The high speed line scanning with array CCD was realized by changing the mode of charge transfer. In order to explore the feasibility of this method, a fast detection system of single point based on linear CCD was designed and fabricated. Seven different LED pulses were measured when the system worked at fast detection mode of single point and normal mode respectively. The results demonstrate that the method of fast detection of single point based on linear CCD is feasible, and the rate of single point detection reaches up to 20 MHz. Thus, in theory, it was proved that transient spectrum detection with array CCD by changing the mode of charge transfer is also feasible.

Phototransformation of tetrabromobisphenol A in saline water under simulated sunlight irradiation.

The widespread use of halogenated flame retardants in recent years has led to the accumulation of TBBPA in water, which may cause potential harm to living organisms. The phototransformation of the flame retardant TBBPA in alkaline saline water under simulated sunlight irradiation was investigated. The effects of abiotic factors such as the initial concentration of TBBPA, chloride ion concentration, solution pH, inorganic anions and cations, dissolved organic matter (DOM) were studied. The results showed that the phototransformation rate of TBBPA accelerated with the decrease of the initial concentration of TBBPA, the increase of chloride ion concentration and solution pH. The scavenging experiments showed that •OH, 1O2, O2•- and 3TBBPA* all participated in the phototransformation of TBBPA. The presence of NO3-, CO32-, SO42-, Mg2+, Ca2+, Fe3+ and fulvic acid (FA) all inhibited the phototransformation of TBBPA in the present study. The phototransformation products of TBBPA were detected by liquid chromatography-mass spectrometry (LC-MS), and the phototransformation pathways were proposed. This is the first report on the photo-induced generation of halogen exchange products from TBBPA in saline solutions, which will contribute to a better understanding of the environmental behavior and risks of BFRs in water.

A large-format streak tube for compressed ultrafast photography.

Streak cameras are powerful imaging instruments for studying ultrafast dynamics with the temporal resolution ranging from picosecond to attosecond. However, the confined detection area limits the information capacity of streak cameras, preventing them from fulfilling their potential in lidar, compressed ultrafast photography, etc. Here, we designed and manufactured a large-format streak tube with a large-size round-aperture gate, a spherical cathode, and a spherical screen, leading to an expanded detection area and a high spatial resolution. The simulation results show that the physical temporal resolution of the streak tube is better than 45 ps and the spatial resolutions are higher than 14 lp/mm in the whole area of 24 × 28 mm2 on the cathode. The experiments demonstrate the streak tube's application potential in weak light imaging benefiting from the imaging magnification of 0.79, a photocathode radiance sensitivity of 37 mA/W, a radiant emitting gain of 11.6 at the wavelength of 500 nm, and a dynamic range higher than 512:1. Most importantly, in the photocathode area of Φ35 mm, the static spatial resolutions at the center and the edge along the slit (R = 16 mm) reach 32 and 28 lp/mm, respectively, and are higher than 10 lp/mm in the whole area of 24 × 28 mm2 on the cathode, allowing for a considerable capacity for spatial information.

[Real-time measurement of detonation transient temperature].

Based on the spectral characteristic of the detonation temperature, the present paper presents a measurement system of transient multi-wavelength pyrometry with the theory of multi-wavelength thermometry. The FPGA was applied as the hardware developing platform and the high-speed linear CCD was utilized. Each module was controlled by FPGA to achieve the process of real-time data acquisition, storage and transmission. Using the multiple regression analysis method, the dynamic spectral waveforms were calculated. The two laser spectral lines, 630 and 532 nm, were used to calibrate the corresponding pixel sequence numbers and the No. 175 and No. 270 were confirmed. In this paper, the halide tungsten light was measured. The results show that the system can sample continuous spectrum signal at several different times; the CCD can stably work with 40 MHz clock and the frame scanning frequency can achieve 73 kHz.

Evaluation of Bone Marrow Texture and Trabecular Changes With Quantitative DCE-MRI and QCT in Alloxan-Induced Diabetic Rabbit Models.

Purpose: To investigate whether the microvascular permeability of lumbar marrow and bone trabecular changes in early-stage diabetic rabbits can be quantitatively evaluated using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), quantitative computed tomography, and texture-analyzed permeability parameter Ktrans map of DCE-MRI. Materials and Methods: This prospective study included 24 rabbits that were randomly assigned to diabetic (n = 14) and control (n = 10) groups. All rabbits underwent sagittal MRI of the lumbar region at 0, 4, 8, 12, and 16 weeks after alloxan injection. Pearson correlation coefficient was performed to determine the correlation between permeability parameter and bone mineral density (BMD). Repeated-measures ANOVA was used to analyze the changes in lumbar BMD over time in each group and the texture parameters of diabetic rabbit lumbar marrow at different time points. Mann-Whitney U rank sum test was used to compare the differences of each index between the two groups and calculate the area under the curve (AUC). Results: BMD was correlated with Ktrans , Kep , and Ve but not with Vp . At weeks 0-16, the BMD of the rabbits in the diabetic and normal groups was not statistically significant, but the change in BMD showed an overall downward trend. For texture analysis, entropy, energy, and Uniformized positive pixel (UPP) parameters extracted from the Ktrans map showed significant differences from week 0 to 16 between the two groups. The identification ability at 8-12 weeks was higher than that at 12-16 weeks, and the AUCs were 0.734, 0.766, and 0.734, respectively (P < 0.05 for all). Conclusions: The changes in BMD measured using quantitative computed tomography occurred later than those measured using bone trabecular morphometry. Texture analysis parameters based on DCE-MRI quantitative parameter Ktrans map are feasible to identify early changes in lumbar marrow structure in diabetic rabbits.

High-Sensitivity and Long-Life Microchannel Plate Processed by Atomic Layer Deposition.

As a key component of electron multiplier device, a microchannel plate (MCP) can be applied in many scientific fields. Pure aluminum oxide (Al2O3) as secondary electron emission (SEE) layer were deposited in the pores of MCP via atomic layer deposition (ALD) to overcome problems such as high dark current and low lifetime which often occur on traditional MCP. In this paper, we systematically investigate the morphology, element distribution, and structure of samples by scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS), respectively. Output current of different thickness of Al2O3 was studied and an optimal thickness was found. Experimental tests show that the average gain of ALD-MCP was nearly five times better than that of traditional MCP, and the ALD-MCP showed better sensitivity and longer lifetime.