3D printing of customized bioceramics for promoting bone tissue regeneration by regulating sympathetic nerve behavior.

Numerous studies have shown that there are multiple neural activities involved in the process of bone resorption and bone regeneration, and promoting osteogenesis by promoting neural network reconstruction is an effective strategy for repairing critical size bone defects. However, traumatic bone defects often cause activation of the sympathetic nervous system (SNS) in the damaged area, releasing excess catecholamines (CAs), resulting in a decrease in the rate of bone formation. Herein, a 3D-printed scaffold loaded with propranolol (PRN) is proposed to reduce CA concentrations in bone defect areas and promote bone regeneration through drug release. For this purpose, PRN-loaded methacrylated gelatin (GelMA) microspheres were mixed with low-concentration GelMA and perfused into a 3D-printed porous hydroxyapatite (HAp) scaffold. By releasing PRN, which can block ß-adrenergic receptors, it hinders the activation of sympathetic nerves and inhibits the release of excess CA by the SNS. At the same time, the composite scaffold recruits bone marrow mesenchymal stem cells (BMSCs) and promotes the differentiation of BMSCs in the direction of osteoblasts, which effectively promotes bone regeneration in the rabbit femoral condyle defect model. The results of the study showed that the release of PRN from the composite scaffold could effectively hinder the activation of sympathetic nerves and promote bone regeneration, providing a new strategy for the treatment of bone defects.

Characters of the MOCA family in wheat and TaMOCA1 function in salt stress tolerance.

MOCA1 encodes the last key glucuronosyltransferase for ionic stress sensor glycosyl inositol phosphoryl-ceramide (GIPCs) biosynthesis in Arabidopsis, which indicates that the MOCA gene family play important role in plant tolerance to salt stress. However, the isolation and function of MOCAs in staple crops have not been reported and the downstream targets of MOCAs in salt stress tolerance signalling pathway are not clear. In this study, we identified 110 MOCA genes in wheat which were classified into five clades and they differed in gene structure, protein length, conserved motifs and expression profiles in different tissues and under salt stress. TaMOCA1 was selected for further functional study in response to salt stress. TaMOCA1 was rapidly induced by NaCl treatment. The 35S::TaMOCA1-GFP construction showed the cell nucleus and cytoplasm location in wheat protoplast. TaMOCA1 over-expressing Arabidopsis seedlings formed longer primary roots and more lateral roots than the wild type ones under 50 mM NaCl treatment. The over-expressing Arabidopsis had higher expression levels of HKT1, but lower expression levels of NHX1 and SOS genes than the wild type. Also, the transgenic plants had higher SOD activity and lower MDA content than the wild Arabidopsis seedling under salt stress. These results may indicate that TaMOCA1 increases salt stress tolerance through decreasing Na+ loading from the xylem parenchyma cells to the xylem via SOS1 and HKT1, hence lowering root-to-shoot delivery of Na? and superior antioxidant ability. All these results lay a foundation for further functional study of MOCAs in wheat.

Characterization of SEC14 family in wheat and the function of TaSEC14-7B in salt stress tolerance.

Phospholipids are important components of plant biofilms and signal transduction. They are divided into glycerophospholipids and sphingolipids. Phosphatidylinositol (PI) is an intracellular glycerophospholipid. SEC14s are PI transporter proteins that are widely presented in eukaryotic. They take part in membrane transportation, inositol phosphate metabolism and adversity stress response. To date, systematic analysis of the SEC14 gene family in wheat, especially the function of SEC14 in salt stress tolerance has not been reported. In this study, 106 SEC14 family members have been identified in wheat. Then, a salt inducible Sec14 family member TaSEC14-7B was selected for further functional study in response to salt stress. Expression analysis demonstrated TaSEC14-7B was induced by NaCl, PEG treatment and localized both in the cell membrane and nucleus. TaSEC14-7B over-expressing Arabidopsis increased salt stress tolerance. Under salt stress, the transgenic plants displayed higher germination rate, longer primary root length, more soluble sugar accumulation, higher antioxidant enzyme activity and lower oxidative damage than the wild type plants. Also, at the presence of NaCl stress, the expression level of ABF4, P5CS, PLC4 and AtPLC7 genes was higher in TaSEC14 transgenic Arabidopsis than in the wild type ones. All these results lay a foundation for further study of Sec14 in wheat.

A low-power and flexible bioinspired artificial sensory neuron capable of tactile perceptual and associative learning.

Biomimetic haptic neuron systems have received a lot of attention from the booming artificial intelligence industry for their wide applications in personal health monitoring, electronic skin, and human-machine interfaces. In this work, inspired by the human tactile afferent nerve, we developed a flexible and low energy consumption artificial tactile neuron, which was constructed by combining a dual network (DN) hydrogel-based sensor and a low power memristor. The tactile sensor (ITO/PAM:CS-Fe3+ hydrogel/ITO) serves as E-skin, with mechanical properties including pressure and stretching. The memristor (Ti:ITO/BiFeO3/ITO) serving as an artificial synapse has low power (∼3.96 × 10-7 W), remarkable uniformity, a large memory window of 500 and excellent plasticity. Remarkably, the pattern recognition simulation based on a neuromorphic network is conducted with a high recognition accuracy of ∼89.81%. In the constructed system, the artificial synapse could be activated by the electrical information from the E-skin induced by an external pressure, to generate excitatory postsynaptic currents. The system shows functions of perception and memory functions, and it also enables tactile associative learning. The present work is important for the development of empowering robots and prostheses with the capability of perceptual learning, and it provides a paradigm for next-generation artificial sensory systems with low-power, wearable and low-cost features.

Tuning reactivity of Bi2MoO6 nanosheets sensors toward NH3 via Ag doping and nanoparticle modification.

Noble metal-doping and modification are proved effective in improving the gas-response performance of semiconductor sensors. In this study, we developed a promising Bi2MoO6 (BMO)-based gas sensor capable of sensing ppb-level NH3 at room temperature via introducing silver (Ag). The BMO samples with different Ag doping and modification ratios were successfully formed via one-step solvothermal and glucose reduction techniques, respectively, which could be confirmed by the results of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) techniques. Compared to bare BMO, the gas-sensing properties of both Ag-doped and Ag surface-modified BMO samples were improved to various extents, respectively. In particular, the 5% Ag-modified BMO sensor with the highest response (Gg/Ga = 37.6 to 200 ppb NH3), long-term stability, and low threshold concentration (50 ppb) at 20% RH. Based on the spillover effect and metal-semiconductor junctions of Ag nanoparticles, the enhanced sensing response towards NH3 can be thoroughly illustrated. Combined with the first-principles calculations, the adsorption energy, density of states, and charge transfer of Ag-modified BMO were further performed to demonstrate the high sensing response and ultra-low detection limit.

A bio-inspired tactile nociceptor constructed by integrating wearable sensing paper and a VO2 threshold switching memristor.

The sensations of touch and pain are fundamental components of our daily life, which can transport vital information about the surroundings and provide protection to our bodies. In this study, the transmission process of sensing pressure stimuli to dorsal root neurons (nociceptors) was simulated using electronic devices. In this regard, we proposed and experimentally demonstrated a biomimetic nociceptor system with tactile perception. In this system, the sensing paper as E-skin simulates the biological skin to sense external pressure stimulation and generate electrical signals, while the threshold switching memristor simulates the biological nociceptor to receive and process the receptor signals. The W/VO2/Pt memristor exhibits all key features of nociceptors including threshold, relaxation, "no adaptation" and sensitization phenomena of allodynia and hyperalgesia. The E-skin shows high sensitivity and a broad sensing range and is capable of monitoring different human movements and physiological signals. With the bio-inspired artificial tactile nociceptive system, the threshold and sensitization properties under pressure stimuli are obtained successfully. Notably, this system could be used as an artificial tactile alarm system to demonstrate the potential applicability of humanoid robots. Thus, the present work is of great significance to the development of hardware architecture in artificial intelligence systems and replacement neuroprosthetics.

Flexible silicon nanowires sensor for acetone detection on plastic substrates.

Acetone commonly exists in daily life and is harmful to human health, therefore the convenient and sensitive monitoring of acetone is highly desired. In addition, flexible sensors have the advantages of light-weight, conformal attachable to irregular shapes, etc. In this study, we fabricated high performance flexible silicon nanowires (SiNWs) sensor for acetone detection by transferring the monocrystalline Si film and metal-assisted chemical etching method on polyethylene terephthalate (PET). The SiNWs sensor enabled detection of gaseous acetone with a concentration as low as 0.1 parts per million (ppm) at flat and bending states. The flexible SiNWs sensor was compatible with the CMOS process and exhibited good sensitivity, selectivity and repeatability for acetone detection at room temperature. The flexible sensor showed performance improvement under mechanical bending condition and the underlying mechanism was discussed. The results demonstrated the good potential of the flexible SiNWs sensor for the applications of wearable devices in environmental safety, food quality, and healthcare.

TaFLZ2D enhances salinity stress tolerance via superior ability for ionic stress tolerance and ROS detoxification.

Salinity stress severely affects plant growth and crop productivity. FCS-like zinc finger family genes (FLZ) play important roles in plant growth and stress responses. But most information of this family obtained was involved in sucrose signaling, limited function has been known in response to salinity stress. In this study, a novel FLZ gene TaFLZ2D has been isolated and characterized in response to salinity stress in wheat. TaFLZ2D was induced by both salinity stress and exogenous abscisic acid (ABA). Its transcript level was substantially higher in the salt resistant wheat cultivar SR3 than in its closely related but salt sensitive cultivar JN177. Transient expression in Nicotiana benthamiana leaf epidermal cells demonstrated TaFLZ2D was localized both in the cytoplasm membrane and nucleus. Constitutive expression of TaFLZ2D in Arabidopsis thaliana improved salinity stress tolerance and ABA sensitivity. Phenotype analysis under KCl and mannitol treatment demonstrated TaFLZ2D increased salinity stress tolerance mainly due to the superior ability to cope with ionic stress. TaFLZ2D over-expressing lines increased abscisic acid synthesis, peroxidase activity and reduced rate of water loss. Transcriptomic analysis demonstrated over-expression of TaFLZ2D regulated ABA-dependent and independent signaling pathway related genes expression and activated antioxidant related genes expression under normal condition and Ca2+ signaling related genes expression under NaCl treatmemt. Taken together, TaFLZ2D is a positive regulator of salinity stress tolerance, which contributes to salinity stress mainly through superior ability for ionic stress tolerance and ROS detoxification.

First-principles prediction of strain-induced gas-sensing tuning in tin sulfide.

A challenge in the application of two-dimensional (2D) SnS in gas-sensing field is that the SnS monolayer is highly sensitive to oxidizing gases, whereas it is naturally deactivated towards reducing gases. The non-sensitivity of SnS to reducing gases is a problem that needs to be solved urgently in an economic and effective manner. Hence, in this work, we propose a strategy of applying strain modulation on the SnS monolayer to optimize its sensitivity and selectivity for reducing gases fundamentally. Generally, the strain modulation applied on a semiconductor gives rise to a change in its band gap (BG). Based on the first-principles calculations, the strain on SnS was found to induce strong degeneracy and energy-level splitting. Unusually, the tensile strain (≥3%) applied could transform the SnS monolayer from indirect-gap semiconductors to direct-gap semiconductors, manifesting a promising optical application prospect but not appropriate for the gas-sensing filed. Comparatively, the compressive strain (≥3%) on SnS could generate new electronic states at the edge of the conduction band of the SnS monolayer, which increases the conductivity and the weak interaction. Thus, the adsorption of reducing gases on the SnS monolayer is enhanced from physisorption to chemisorption, resulting in a considerable increase in the sensitivity performance to the three reducing gas molecules (NH3, H2S, and CO). The induced symmetry breaking of the SnS monolayer under compressive strain leads to much higher surface activation towards reducing gases, which improves its adsorption capability and the ability of screening oxidizing gas molecules. The present work provides key information for novel designs of strain-sensitive dual-function sensors based on SnS.

Genome-Wide Association Study Uncover the Genetic Architecture of Salt Tolerance-Related Traits in Common Wheat (Triticum aestivum L.).

Soil salinity is a serious threat to wheat yield affecting sustainable agriculture. Although salt tolerance is important for plant establishment at seedling stage, its genetic architecture remains unclear. In the present study, we have evaluated eight salt tolerance-related traits at seedling stage and identified the loci for salt tolerance by genome-wide association study (GWAS). This GWAS panel comprised 317 accessions and was genotyped with the wheat 90 K single-nucleotide polymorphism (SNP) chip. In total, 37 SNPs located at 16 unique loci were identified, and each explained 6.3 to 18.6% of the phenotypic variations. Among these, six loci were overlapped with previously reported genes or quantitative trait loci, whereas the other 10 were novel. Besides, nine loci were detected for two or more traits, indicating that the salt-tolerance genetic architecture is complex. Furthermore, five candidate genes were identified for salt tolerance-related traits, including kinase family protein, E3 ubiquitin-protein ligase-like protein, and transmembrane protein. SNPs identified in this study and the accessions with more favorable alleles could further enhance salt tolerance in wheat breeding. Our results are useful for uncovering the genetic mechanism of salt tolerance in wheat at seeding stage.

Layered Double Oxides for Sensing Reducing Volatile Organic Compounds: The Effect of Local Charge Region Modulation.

Multi-metal oxides with uniform distribution of various metal elements have potential for an enhanced gas-sensing response due to the strong heterogeneous and synergistic effects involved. In this study, three layered double oxides, labeled as CuCr-, ZnCr-, and ZnTi-LDOs, respectively, were prepared with corresponding LDHs (layered double hydroxides) as precursors and self-sacrificial templates. The elemental mapping confirms the uniform distribution of hetero-metal elements in whole LDOs. The CuCr-LDOs exhibits a much larger sensing response towards reducing VOCs at room temperature, which is 3.5 or 13.3 times that of ZnCr- or ZnTi-LDOs, respectively. The response differences are analyzed in terms of the local charge region modulation associated with heterojunction formation, and it is further demonstrated based on first-principles calculations and valence electron theory. The present work suggests a possible strategy for developing highly sensitive oxide-based gas sensors for VOCs detection.

Using Deep Neural Network to Diagnose Thyroid Nodules on Ultrasound in Patients With Hashimoto's Thyroiditis.

OBJECTIVE: The aim of this study is to develop a model using Deep Neural Network (DNN) to diagnose thyroid nodules in patients with Hashimoto's Thyroiditis. METHODS: In this retrospective study, we included 2,932 patients with thyroid nodules who underwent thyroid ultrasonogram in our hospital from January 2017 to August 2019. 80% of them were included as training set and 20% as test set. Nodules suspected for malignancy underwent FNA or surgery for pathological results. Two DNN models were trained to diagnose thyroid nodules, and we chose the one with better performance. The features of nodules as well as parenchyma around nodules will be learned by the model to achieve better performance under diffused parenchyma. 10-fold cross-validation and an independent test set were used to evaluate the performance of the algorithm. The performance of the model was compared with that of the three groups of radiologists with clinical experience of <5 years, 5-10 years, >10 years respectively. RESULTS: In total, 9,127 images were collected from 2,932 patients with 7,301 images for the training set and 1,806 for the test set. 56% of the patients enrolled had Hashimoto's Thyroiditis. The model achieved an AUC of 0.924 for distinguishing malignant and benign nodules in the test set. It showed similar performance under diffused thyroid parenchyma and normal parenchyma with sensitivity of 0.881 versus 0.871 (p = 0.938) and specificity of 0.846 versus 0.822 (p = 0.178). In patients with HT, the model achieved an AUC of 0.924 to differentiate malignant and benign nodules which was significantly higher than that of the three groups of radiologists (AUC = 0.824, 0.857, 0.863 respectively, p < 0.05). CONCLUSION: The model showed high performance in diagnosing thyroid nodules under both normal and diffused parenchyma. In patients with Hashimoto's Thyroiditis, the model showed a better performance compared to radiologists with various years of experience.

Identification and Characterization of Wheat Germplasm for Salt Tolerance.

Salinity is one of the limiting factors of wheat production worldwide. A total of 334 internationally derived wheat genotypes were employed to identify new germplasm resources for salt tolerance breeding. Salt stress caused 39, 49, 58, 55, 21 and 39% reductions in shoot dry weight (SDW), root dry weight (RDW), shoot fresh weight (SFW), root fresh weight (RFW), shoot height (SH) and root length (RL) of wheat, respectively, compared with the control condition at the seedling stage. The wheat genotypes showed a wide genetic and tissue diversity for the determined characteristics in response to salt stress. Finally, 12 wheat genotypes were identified as salt-tolerant through a combination of one-factor (more emphasis on the biomass yield) and multifactor analysis. In general, greater accumulation of osmotic substances, efficient use of soluble sugars, lower Na+/K+ and a higher-efficiency antioxidative system contribute to better growth in the tolerant genotypes under salt stress. In other words, the tolerant genotypes are capable of maintaining stable osmotic potential and ion and redox homeostasis and providing more energy and materials for root growth. The identified genotypes with higher salt tolerance could be useful for developing new salt-tolerant wheat cultivars as well as in further studies to underline the genetic mechanisms of salt tolerance in wheat.

First-principles calculations combined with experiments to study the gas-sensing performance of Zn-substituted SnS.

Two-dimensional group-IV monochalcogenides MX (M = Ge, and Sn; X = S, and Se) are explored for their potential in gas-sensing applications. In this work, a combined theoretical and experimental study on pure SnS and Zn-substituted SnS for promising methanol sensors is performed. The adsorption characteristics of methanol on pure and Zn-substituted SnS were first calculated using first-principles based on density functional theory (DFT). It is clarified theoretically that the incorporation of Zn dopant could enhance the adsorption capability of the SnS surface to methanol molecules, thus achieving obvious response enhancement and selectivity improvement. Further experimental investigation is carried out based on the successful synthesis of pure and Zn-substituted SnS with hierarchical architecture via a one-step solvothermal process. Gas-sensing measurement indicates that the Zn-substituted SnS sensor is promising for selective detection of rarefied methanol. At room temperature, the as-synthesized hierarchical SnS with an appropriate amount of Zn-doping can sense methanol vapor of as low as 100 ppb. In particular, Zn-doping can enhance the sensing response of methanol significantly, with a 32.8-fold increase in response value achieved in comparison to that of the pure SnS. The underlying mechanism for the response enhancement of Zn-substituted SnS is also analyzed and demonstrated in detail. The present work demonstrates that Zn-doping is highly effective for improving the response and selectivity of SnS towards methanol vapor, and the Zn-substituted SnS is promising for highly sensitive methanol sensors with low consumption.

A genome-wide analysis of pentatricopeptide repeat (PPR) protein-encoding genes in four Gossypium species with an emphasis on their expression in floral buds, ovules, and fibers in upland cotton.

Cotton is the most important natural fiber used in textiles. Breeding for "three-lines", i.e., cytoplasmic male sterility (CMS)-based sterile (A), maintainer (B), and restorer (R) line, is a promising approach to harness hybrid vigor in cotton. Pentatricopeptide repeat (PPR) protein-encoding genes play an important role in plant growth and development including restoration of CMS plants to male fertility. However, PPRs, especially those contributing to CMS and fiber development, remain largely unknown in cotton. In this study, a genome-wide identification and characterization of PPR gene family in four Gossypium species with genome sequences (G. arboreum, G. raimondii, G. hirsutum, and G. barbadense) were performed, and expressed PPR genes in developing floral buds, ovules, and fibers were compared to identify possible PPRs related to CMS restoration and fiber development. A total of 539, 558, 1032, and 1055 PPRs were predicted in the above four species, respectively, which were further mapped to chromosomes for a synteny analysis. Through an RNA-seq analysis, 86% (882) PPRs were expressed in flowering buds of upland cotton (G. hirsutum); however, only 11 and 6 were differentially expressed (DE) between restorer R and its near-isogenic (NI) B and between R and its NI A line, respectively. Another RNA-seq analysis identified the expression of only 54% (556) PPRs in 0 and 3 day(s) post-anthesis (DPA) ovules and 24% (247) PPRs in 10 DPA fibers; however, only 59, 6, and 27 PPRs were DE in 0 and 3 DPA ovules, and 10 DPA fibers between two backcross inbred lines (BILs) with differing fiber length, respectively. Only 2 PPRs were DE between Xuzhou 142 and its fiberless and fuzzless mutant. Quantitative RT-PCR analysis confirmed the validity of the RNA-seq results for the gene expression pattern. Therefore, only a very small number of PPRs may be associated with fertility restoration of CMS and genetic differences in fiber initiation and elongation. These results lay a foundation for understanding the roles of PPR genes in cotton, and will be useful in the prioritization of candidate PPR gene functional validation for cotton CMS restoration and fiber development.

Effect of the Functionalization of Porous Silicon/WO3 Nanorods with Pd Nanoparticles and Their Enhanced NO2-Sensing Performance at Room Temperature.

The decoration of noble metal nanoparticles (NPs) on the surface of metal oxide semiconductors to enhance material characteristics and gas-sensing performance has recently attracted increasing attention from researchers worldwide. Here, we have synthesized porous silicon (PS)/WO3 nanorods (NRs) functionalized with Pd NPs to enhance NO2 gas-sensing performance. PS was first prepared using electrochemical methods and worked as a substrate. WO3 NRs were synthesized by thermally oxidizing W film on the PS substrate. Pd NPs were decorated on the surface of WO3 NRs via in-situ reduction of the Pd complex solution by using Pluronic P123 as the reducing agent. The gas-sensing characteristics were tested at different gas concentrations and different temperatures ranging from room temperature to 200 °C. Results revealed that, compared with bare PS/WO3 NRs and Si/WO3 NRs functionalized with Pd NPs, the Pd-decorated PS/WO3 NRs exhibited higher and quicker responses to NO2, with a detection concentration as low as 0.25 ppm and a maximum response at room temperature. The gas-sensing mechanism was also investigated and is discussed in detail. The high surface area to volume ratio of PS and the reaction-absorption mechanism can be explained the enhanced sensing performance.

Hierarchical layered double hydroxides with Ag nanoparticle modification for ethanol sensing.

Layered double hydroxides (LDHs) have recently been revealed to be promising in gas sensor applications due to their compositional flexibility and unique 2D-interlayer channel for gas diffusion and adsorption. This work demonstrates highly porous hierarchical LDHs containing Mg2+ and Al3+ (MgAl-LDHs) for ethanol sensing at room temperature. These MgAl-LDHs, with unique flower-like hierarchical structure and mesoporous interlayer, were synthesized hydrothermally using sodium dodecyl sulfate as soft template as well as intercalating agent. Further modification by discrete Ag nanoparticles (NPs) was achieved via an environmentally friendly glucose-reduction method to improve the gas-sensing response of the LDH-based sensor. It is found that the hierarchical MgAl-LDHs show potential in sensing ethanol gas with rapid dynamic characteristics at room temperature; their response magnitude towards ethanol can be enhanced significantly by Ag NP modification. The gas-response value of the Ag-modified MgAl-LDH sensor is about twice that of pristine MgAl-LDH sensors, towards 5-200 ppm ethanol at room temperature. Meanwhile, rapid response-recovery characteristics are achieved, with response and recovery times shorter than 10 and 50 s, respectively. The satisfactory sensing performance and remarkable response enhancement by Ag NP modification are demonstrated in terms of the unique microstructure of the hierarchical MgAl-LDHs and a constructed conductive effect model of Ag functionalized LDHs.

Ultrasensitive Silicon Nanowire Sensor Developed by a Special Ag Modification Process for Rapid NH3 Detection.

Surface functionalization is very effective in enhancing sensing properties of a chemiresistive gas sensor. In this work, we develop a novel and cost-effective process to prepare Ag-modified silicon nanowire (SiNW) sensors and further suggest a resistance effect model to clarify the enhanced sensing mechanism of Ag-modified SiNWs. The SiNWs were formed via metal-assisted chemical etching (MACE), and the Ag nanoparticle (NP) modification was achieved in situ based on the MACE-produced Ag dendrites by involving a crucial anisotropic postetching of TMAH. The TMAH etching induces a loose array of needle-like, rough SiNWs (RNWs) with firm attachment of tiny Ag NPs. Comparative investigations for NH3-sensing properties indicate that the RNWs modified by discrete Ag NPs (Ag@RNWs) display an ∼3-fold enhancement in gas response at room temperature compared with pristine SiNWs. Meanwhile, transient response and ultrafast recovery are observed for the Ag@RNW sensor (tres ≤ 2 s and trec ≤ 9 s to 0.33-10 ppm of NH3). The study demonstrates the considerable effect and potential of the Ag modification process developed in this work. A resistance effect model was further suggested to clarify the underlying mechanism of the enhanced response and the response saturation characteristic of the Ag@RNWs. The promotion of TMAH etching-induced microstructure modulation to sensing properties was also demonstrated.

Expression profiles of a cytoplasmic male sterile line of Gossypium harknessii and its fertility restorer and maintainer lines revealed by RNA-Seq.

The Gossypium harknessii background cytoplasmic male sterility (CMS) system has been used in cotton hybrid breeding in China. However, the mechanism underlying pollen abortion and fertility restoration in CMS remains to be determined. In this study, we used RNA-seq to identify critical genes and pathways associated with CMS in G. harknessii based CMS lines (588A), the near isogenic restorer lines (588R), and maintainer lines (588B). We performed an assembly of 80,811,676 raw reads into 89,939 high-quality unigenes with an average length of 698 bp. Among these, 72.62% unigenes were annotated in public protein databases and were classified into functional clusters. In addition, we investigated the changes in expression of genes between 588A and 588B (588R); the RNA-seq data showed 742 differentially expressed genes (DEGs) between 588A and 588B and 748 DEGs between 588A and 588R. They were mainly down-regulated in 588A and most of them distributed in metabolic and biosynthesis of secondary metabolites pathways. Further analysis revealed 23 pollen development related genes were differentially expressed between 588A and 588B. Numerous genes associated with tapetum development were down-regulated in 588A, implicating tapetum dysplasia may be a key reason for pollen abortion in CMS lines. Also, among DEGs between 588A and 588R, we identified two PPR genes which were highly up-regulated in restorer line. This study may provide assistance for detailed molecular analysis and a better understanding of harknessii based CMS in cotton.

KOH post-etching-induced rough silicon nanowire array for H2 gas sensing application.

The limited surface area and compacted configuration of silicon nanowires (SiNWs), which are made by one-step metal-assisted chemical etching (MACE) go against target gas diffusion and adsorbtion for gas sensing application. To harvest suitable gas sensitivity and fast response-recovery characteristics, an aligned, rough SiNW array with loose configuration and high surface area was fabricated by a two-step etching process. The MACE technique was first employed to fabricate a smooth SiNW array, and then a KOH post-etching method was developed to roughen the NW surface further. The influence of the KOH post-etching time on the array density and surface roughness of the SiNWs was investigated, and the H2-sensing properties of the sensor based on the as-fabricated rough SiNW array were evaluated systematically at room temperature. It was revealed that the post-etching of KOH roughens the NW surface effectively, and also decreases the wire diameter and array density considerably. The resulting configuration of the SiNW array with high active surface and loose geometry is favorable for gas sensing. Consequently, the rough SiNW array-based sensor exhibited a linear response to H2 with a wide range of concentrations (50-10 000 ppm) at room temperature. Good stability and selectivity, satisfying response-recovery characteristics were also achieved. However, over-etching of SiNWs by KOH solution results in a considerable decrease in surface roughness and then in the H2-sensing response of the NWs.