Spanish Melon Landraces: Revealing Useful Diversity by Genomic,Morphological, and Metabolomic Analysis

Spain is a secondary centre of the diversification of the melon (Cucumis melo L.), with high diversity represented in highly appreciated landraces belonging to the Flexuosus and Ibericus groups. A collection of 47 accessions of Flexuosus, Chate, Piel de Sapo, Tendral, Amarillo, Blanco, and Rochet was analysed using a genotyping-by-sequencing (GBS) approach. A total of 66,971 quality SNPs were identified. Genetic analysis differentiated Ibericus accessions and exotic materials (Ameri, Momordica, Kachri, and Agrestis), while Flexuous accessions shared ancestry between them. Within the Ibericus group, no clear genomic distinction could be identified for the different landraces evaluated, with accessions of different landraces showing high genetic similarity. The morphological characterization confirmed that the external colour and fruit shape had been used as recognition patterns for Spanish melon landraces, but variability within a landrace exists. Differences were found in the sugars and acid and volatile profiles of the materials. Flexuosus and Chate melons at the immature commercial stage accumulated malic acid and low levels of hexoses, while Ibericus melons accumulated high contents of sucrose and citric acid. Specific trends could be identified in the Ibericus landraces. Tendral accumulated low levels of sugars and citric acid and high of malic acid, maintaining higher firmness, Rochet reached higher levels of sugars, and Amarillo tended to lower malic acid contents. Interestingly, high variability was found within landraces for the acidic profile, offering possibilities to alter taste tinges. The main volatile organic compounds (VOCs) in Flexuosus and Chate were aldehydes and alcohols, with clear differences between both groups. In the Ibericus landraces, general trends for VOC accumulation could be identified, but, again, a high level of variation exists. This situation highlights the necessity to develop depuration programs to promote on-farm in situ conservation and, at the same time, offers opportunities to establish new breeding program targets and to take advantage of these sources of variation.     

矿井移动机器人运动控制系统研究

介绍了一种可在矿井等未知环境下自主工作的移动机器人运动控制系统设计.该控制系统采用32位单片机S3C2410ARM作为处理器,利用直流电机作为驱动装置.当机器人遇到周围障碍物的情况下能快速、自主地调节行驶速度和行驶方向,该系统具有动态性能好、启动速度快、运行稳定性强等特点.     

Combination of Sanguisorbigenin and Conventional Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus: Inhibition of Biofilm Formation and Alteration of Cell Membrane Permeability

Methicillin-resistant Staphylococcus aureus (MRSA) infection is challenging to eradicate because of antibiotic resistance and biofilm formation. Novel antimicrobial agents and alternative therapies are urgently needed. This study aimed to evaluate the synergy of sanguisorbigenin (SGB) isolated from Sanguisorba officinalis L. with six conventional antibiotics to achieve broad-spectrum antibacterial action and prevent the development of resistance. A checkerboard dilution test and time-to-kill curve assay were used to determine the synergistic effect of SGB combined with antibiotics against MRSA. SGB showed significant synergy with antibiotics and reduced the minimum inhibitory concentration of antibiotics by 2–16-fold. Biofilm inhibition assay, quantitative RT-PCR, crystal violet absorption, and transmission electron microscopy were performed to evaluate the synergy mechanism. The results indicated that SGB could inhibit biofilm formation and alter cell membrane permeability in MRSA. In addition, SGB was found to exhibit quite low cytotoxicity and hemolysis. The discovery of the superiority of SGB suggests that SGB may be an antibiotic adjuvant for use in combination therapy and as a plant-derived antibacterial agent targeting biofilms.     

Integrated Analysis of Microarray,Small RNA,and Degradome Datasets Uncovers the Role of MicroRNAs in Temperature-Sensitive Genic Male Sterility in Wheat

Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.     

基于特征断面的复杂巷道段三维建模

为解决巷道断面随工程需要及岩层变化不断改变,导致巷道三维建模程序复杂的问题,提出基于特征断面的巷道三维建模思想,通过建立巷道特征断面模型库,实现变化巷道段的三维建模,以期提高复杂巷道段的建模效率。首先阐述建模数据的采集方法,并对巷道断面进行了细化坐标分析;同时提出拐角处断面变化巷道段的平滑处理算法（通过圆弧来圆滑拐角处巷道中心线）,对普通巷道段采用三角剖分形成三角网完成巷道段的建模;而巷道断面发生变化的复杂巷道段存在简单曲面四边形,采用Bézier曲面及曲面的拼接完成巷道段的建模,并在实验中进行了验证     

Enantioselective extraction of terbutaline enantiomers by lipophilic tartaric acid

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Accurate closed-form expressions for the electromagnetic parameters of the shielded split ring line

Based on rigorous analysis of finite element method (FEM), moment method (MoM), and curves fitting techniques, a set of closed-form formulas for the characteristic impedance and the primary (L and C) parameters of the shielded split ring line, are presented. The general expressions give a good accuracy for a wide-range of discontinuity angles and are suitable for all shielded split ring lines which have an outer–inner conductors radius ratio between 2 and 10. These expressions can be easily implemented in CAD simulation tools, to design many components as RF resonators, filters, transmission lines, for wireless communication and probes for material characterization. The results of the design of an RF resonator using the shielded split ring line are presented.     

Fatigue of materials used in microscopic components

This paper discusses the fatigue behaviour of materials used in microscopic components, which are defined as components in which the section size is between one and ten grain diameters. Experimental data were obtained on microscopic and conventional (macroscopic) notched specimens of 316L stainless steel, which is used in many biomedical components including the cardiovascular stent. Microscopic specimens showed unusual behaviour: low threshold values and very flat stress‐life(S‐N) curves. The low threshold values were attributed to the extremely small thickness, which may be preventing closure; a secondary contribution may be coming from a change in the length of non‐propagating cracks. Good predictions could be achieved using the Smith–Miller approach and the theory of critical distances (TCD) if this reduced threshold was taken into account or if, alternatively, the critical distance was made equal to the grain size.     

Morphological and Microstructural Aspects of Metal Dusting on 304L Stainless Steel with Different Surface Treatments

The effect of surface treatment on the susceptibility to metal dusting of 304L stainless steel (SS) exposed in a mixed gas of CO/CO₂ = 100/1 in the temperature ranging from 500–700 °C was investigated. Thermogravimetric analyses (TGA) and long-term exposure tests in the above environments, followed by surface-morphological examination and cross-section chemical composition and microstructure analyses were conducted. The results showed that the decomposition of CO gas to form graphite and nano-sized carbon filaments was affected by the surface pre-treatment applied on the 304L SS. Enhanced carbon deposition but with a significant resistance to metal dusting was found on the sand-blasted 304L SS. The existence of an initial non-protective oxide on the pre-oxidized 304L SS surface, however, gave rise to the highest susceptibility to metal-dusting-associated-localized attack. The roles of different surface treatments on the reactions between 304L SS and the exposing gas environment are discussed.