A Context-Aware Navigation Framework for Ground Robots in Horticultural Environments.

Environmental mapping and robot navigation are the basis for realizing robot automation in modern agricultural production. This study proposes a new autonomous mapping and navigation method for gardening scene robots. First, a new LiDAR slam-based semantic mapping algorithm is proposed to enable the robots to analyze structural information from point cloud images and generate roadmaps from them. Secondly, a general robot navigation framework is proposed to enable the robot to generate the shortest global path according to the road map, and consider the local terrain information to find the optimal local path to achieve safe and efficient trajectory tracking; this method is equipped in apple orchards. The LiDAR was evaluated on a differential drive robotic platform. Experimental results show that this method can effectively process orchard environmental information. Compared with vnf and pointnet++, the semantic information extraction efficiency and time are greatly improved. The map feature extraction time can be reduced to 0.1681 s, and its MIoU is 0.812. The resulting global path planning achieved a 100% success rate, with an average run time of 4ms. At the same time, the local path planning algorithm can effectively generate safe and smooth trajectories to execute the global path, with an average running time of 36 ms.

Plasmon-Mediated Oxidase-like Activity on Ag@ZnS Heterostructured Hollow Nanowires for Rapid Visual Detection of Nitrite.

Rational design of fast and sensitive determination of nitrite (NO2-) from a complicated actual sample overtakes a crucial role in constructing a high-efficiency sensing platform. Herein, a visual NO2- sensing platform with outstanding selectivity, sensitivity, and stability based on a surface plasmon resonance (SPR)-enhanced oxidase-like activity has been proposed. Benefiting from the intrinsic photocatalytic activity and limited light penetration of ZnS, the oxidase-like activity based on ZnS decorated on Ag nanowires (Ag@ZnS) is determined. It is demonstrated that the electrons are generated efficiently on the surface of ZnS and then transferred into the hot electrons of Ag with the help of localized SPR excitation, thus greatly oxidating the colorless 3,3',5,5'-tetramethylbenzidine (TMB) to produce dark blue oxidized TMB (oxTMB). When nitrite is added into the reaction system, the oxTMB will selectively react with NO2- to generate diazotized oxTMB, leading to a visual color change from dark blue to light green and subsequently to dark yellow. Owing to the specific recognition between nitrite and oxTMB, the recovery of catalytic activity induced an enhanced colorimetric test with a wider linear range for NO2- determination, an ultralow detection limit of 0.1 µM, excellent selectivity, and practicability for application in real samples. This plasmon-enhanced oxidase-like activity not only provides a smart approach to realize a colorimetric assay with high sensitivity and simplicity but also modulates oxidase-like activities.

[Effects of methylenetetrahydrofolate reductase gene polymorphism and long-term exposure to organophosphorus pesticides on type 2 diabetes mellitus].

OBJECTIVE: To investigate the effect of the interaction between methylenetetrahydrofolate reductase(MTHFR) genotype and allele and long-term exposure to organophosphorus pesticides on the development of type 2 diabetes mellitus(T2 DM). METHODS: A total of 209 cases of T2 DM(case group) and 216 cases without T2 DM(control group) were selected as subjects. The polymorphism of MTHFR(rs1801133) was detected by TaqMan probe technique. The relationship between genes, long-term exposure to organophosphorus pesticides and T2 DM was analyzed by Logistic regression. The interaction between gene and long-term exposure to organophosphorus pesticides was discussed by crossover analysis and generalized multifactor dimensionality reduction. RESULTS: BMI⇿4, residence in countryside, long-term exposure to organophosphorus pesticides and family history of diabetes mellitus were risk factors for T2 DM. MTHFR genotype distribution conformed to Hardy-Weinberg equilibrium(P>0. 05). There was no significant difference in genotype distribution frequency between case group and control group. The risk of T2 DM in individuals with CT and TT genotypes was 1. 667 times higher than that of CC genotypes after adjusting the covariates at rs1801133 locus in the dominant model(95%CI 1. 057-2. 627, P=0. 028). It suggested that the samples of allele T had a increased risk of T2 DM compared with those without allele T. The above models still had statistical significance(P<0. 05) after adjusting the covariates. Forth, crossover analysis showed that the gene MTHFR(rs1801133) and long-term exposure to organophosphorus pesticides had multiplication interaction. The interaction between gene MTHFR(rs1801133) and long-term exposure to organophosphorus pesticides may play a role in the pathogenesis of T2 DM. Generalized multifactor dimensionality reduction(GMDR)analysis showed that the interaction model of MTHFR(rs1801133) gene and family history of diabetes mellitus was the best model. CONCLUSION: MTHFR(rs1801133) gene CT and TT genotype may be risk factors for T2 DM. The interaction between genetic polymorphism and environmental factors increases the risk of T2 DM.

Fast Attack Detection for Cyber-Physical Systems Using Dynamic Data Encryption.

To defend the cyber-physical system (CPSs) from cyber-attacks, this work proposes an unified intrusion detection mechanism which is capable to fast hunt various types of attacks. Focusing on securing the data transmission, a novel dynamic data encryption scheme is developed and historical system data is used to dynamically update a secret key involved in the encryption. The core idea of the dynamic data encryption scheme is to establish a dynamic relationship between original data, secret key, ciphertext and its decrypted value, and in particular, this dynamic relationship will be destroyed once an attack occurs, which can be used to detect attacks. Then, based on dynamic data encryption, a unified fast attack detection method is proposed to detect different attacks, including replay, false data injection (FDI), zero-dynamics, and setpoint attacks. Extensive comparison studies are conducted by using the power system and flight control system. It is verified that the proposed method can immediately trigger the alarm as soon as attacks are launched while the conventional χ2 detection could only capture the attacks after the estimation residual goes over the predetermined threshold. Furthermore, the proposed method does not degrade the system performance. Last but not the least, the proposed dynamic encryption scheme turns to normal operation mode as the attacks stop.

Plasmon-Stimulated Colorimetry Biosensor Array for the Identification of Multiple Metabolites.

Rationally designing highly catalytic and stable nanozymes for metabolite monitoring is of great importance because of their huge potential in early disease diagnosis. Herein, a novel nanozyme based on hierarchically structured CuS/ZnS with a highly efficient peroxidase (POD)-mimic capability was developed and synthesized for multiple metabolite determination and recognition via the plasmon-stimulated biosensor array strategy. The designed nanozyme can simultaneously harvest plasmon triggered hot electron-hole pairs and generate photothermal properties, leading to a sharply boosted POD-mimic capability under 808 nm laser irradiation. Interestingly, because of the interaction diversity of the metabolite with POD-like nanomaterials, the unique inhibitory effect of metabolites on the POD-mimic activity could be the signal response as the differentiation. Thus, utilizing TMB as a typical chromogenic substrate in the addition of H2O2, the designed colorimetric biosensor array can produce diverse fingerprints for the three vital metabolisms (cysteine (Cys), ascorbic acid (AA), and glutathione (GSH)), which can be precisely identified by principal component analysis (PCA). Notably, a distinct fingerprint of a single metabolite with different levels and metabolite mixtures is also achieved with a detection limit of 1 µM. Most importantly, cell lysis could be effectively discriminated by the biosensor assay, implying its great potential in clinical diagnosis.

Heterojunction MnO2-nanosheet-decorated Ag nanowires with enhanced oxidase-like activity for the sensitive dual-mode detection of glutathione.

The biocatalytic design of nanomaterials with enzyme-like activity is considered a reliable and promising toolkit for the generation of diagnostic agents in complex biological microenvironments. However, the preparation of nanomaterials while maintaining a high catalytic activity in tumor cells (pH 6.0-6.5) poses a prominent challenge. Herein, we constructed a biomimetic enzyme-trigged dual-mode system with colorimetry at 652 nm and photothermal biosensors to detect glutathione based on hollow MnO2-nanosheet-decorated Ag nanowires (Ag@MnO2) as an oxidase-like nanozyme. As expected, Ag@MnO2 catalyzed the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the absence of H2O2, leading to a blue-colored oxidized TMB (oxTMB) that displayed oxidase-like activity in pH 6.0. Interestingly, the portable dual-mode colorimetry and photothermal method for GSH was developed based on the redox reaction between GSH and oxTMB. This detection method exhibited a wide linear range of 0.1-55 µM for GSH with a low detection limit of 0.08 µM. This work highlights a new insight into nanotechnology by taking advantage of biomimetic design in biological analysis.

An outbreak of lethal toxoplasmosis in pigs in the Gansu province of China.

In October 2004, a swine farm in Jinchang, Gansu Province, China, experienced an outbreak of toxoplasmosis. Most of the affected pigs had a rectal temperature greater than 40 degrees C and gradually lost their appetite. Morbidity reached 57%, and mortality was approximately 2%. Analysis of blood samples from affected pigs using hemagglutination inhibition (HI) assay, immunoglobulin G-enzyme-linked immunosorbent assay (IgG-ELISA), and IgM-ELISA tests showed high titers of anti-Toxoplasma gondii antibody. Tachyzoites of T. gondii were found in body fluids of mice inoculated intraperitoneally with ground samples from the heart, liver, spleen, and brain of 2 sick pigs. In addition, the inoculation of 5 pigs with T. gondii tachyzoites caused death in 2 of the pigs. The origin of this outbreak was concluded to be food-borne T. gondii infection.

Screening, identification, and low-energy ion modified breeding of a yeast strain producing high level of 3-hydroxypropionic acid.

3-Hydroxypropionic acid (3HP) is an important platform chemical with a wide range of applications. The biological preparation of this compound is safe and low cost. In this study, orchard soil and human waste were used as raw materials to screen microbial strains that could produce 3HP in selective medium containing varying amounts of propionic acid. A yeast strain that can use propionic acid as substrate and produce 48.96 g/L 3HP was screened. Morphological observation, physiological and biochemical identification, and 26s rDNA sequencing identified the IS451 strain as Debaryomyces hansenii. The low-energy ion N+ , with the energy of 10 keV and a dose of 70 × 2.6 × 1013  ions/cm2 , was implanted into the IS451 strain. The mutant strain WT39, whose 3HP titer reached 62.42 g/L, was obtained. The strain exhibited genetic stability and tolerance to high concentrations of propionic acid and was considered to have broad application prospects.

Intramedullary cervical spinal cord teratoma.

BACKGROUND: Intramedullary cervical spinal cord teratomas (ICTs) are extremely rare, and diagnosis and treatment are challenging. We conducted a systematic review of the literature on the diagnosis and treatment of ICT. METHOD: The presentation, imaging manifestations, diagnosis, management, surgery findings, prognosis and histology were reviewed following Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines. English-language studies and case reports published from inception to 2018 were retrieved. Data on presentation, imaging characteristics, diagnosis, management, surgery findings, outcomes, and histopathology were extracted. RESULTS: Ten articles involving 10 patients were selected. The lesions were located in the upper cervical vertebrae in 4 cases, whereas in the lower cervical vertebrae in the remaining 6 cases. In 5 cases, the lesions were located on the dorsal side of the spinal cord, and in the center of the spinal cord in the remaining 5 cases. Quadriparesis (60%), paraplegia (30%), monoplegia (10%), and neck pain (50%) were the main presentations. The lesion appeared as a intramedullary heterogeneous signal during an MRI scan, and the lesion signal would be partially enhanced after the contrast medium was applied. All patients underwent surgical intervention through a posterior approach. Neurological function improved postoperatively in all patients. Two patients with pathology confirmed to be immature teratomas experienced recurrence. CONCLUSION: ICTs are extremely rare entities that are mainly located in the center or dorsal part of the spinal cord which mainly manifest as quadriplegia and neck pain. MRI is a useful modality that provides diagnostic clues. Surgery from a posterior approach is the primary treatment, and the effect of adjuvant therapy remains uncertain. The prognosis is mainly related to the pathological nature of the tumor and not the method of resection.

A new combination of RNA-mediated DNA ligation and on-chip elongation for detecting viral RNA.

We describe a novel method that combines RNA-mediated DNA ligation and on-chip elongation for detecting viral RNA. These virus species-specific detection probes (DPs) were designed to match sequences of the "target" virus and then chemically synthesized into 2 parts. If the target virus exists, 2 parts of the DP can be ligated by T4 DNA ligase. The ligated DP was hybridized to its corresponding capture probe (CP) on a DNA array. Then, an on-chip DNA polymerization (including Cy3-dUTP) was performed using the ligated DP as a template and the CP as a primer, which resulted in a reporting fluorescent signal. If the target virus does not exist in a sample, no fluorescence signal is produced. Four common tobacco viruses, tobacco mosaic virus, cucumber mosaic virus, potato virus Y, and potato virus X in single and mixed infections were successfully detected by this method. The sensitivity of the detection limit of this assay is 10 times higher than that of ELISA. The minimum dilution detection limit of this assay was 10(-4) (infected sap/healthy sap). The method has the potential to detect any viral RNA from animal, germs, or fungi where the sequence is known.

MiR-3188 Inhibits Non-small Cell Lung Cancer Cell Proliferation Through FOXO1-Mediated mTOR-p-PI3K/AKT-c-JUN Signaling Pathway.

This study investigated the role of miR-3188 on the proliferation of non-small cell lung cancer cells and its relationship to FOXO1-modulated feedback loop. Two non-small cell lung cancer (NSCLC) cell lines A549 and H1299 were used. RNA silencing was achieved by lentiviral transfection. Cell proliferation was assessed by immunohistochemical staining of Ki67 and PCNA, Edu incorporation, and colony formation assay. Western blotting was used to examine expression of FOXO1, mTOR, p-mTOR, CCND1, p21, c-JUN, AKT, pAKT, PI3K, p-PI3K, and p27 proteins. It was found that miR-3188 reduced cell proliferation in NSCLC cells. Molecular analyses indicated that the effect of mammalian target of rapamycin (mTOR) was directly mediated by miR-3188, leading to p-PI3K/p-AKT/c-JUN inactivation. The inhibition of this signaling pathway further caused cell-cycle suppression. Moreover, FOXO1 was found to be involved in regulating the interaction of miR-3188 and mTOR through p-PI3K/p-AKT/c-JUN signaling pathway. Taken together, our study demonstrated that miR-3188 interacts with mTOR and FOXO1 to inhibit NSCLC cell proliferation through a mTOR-p-PI3K/AKT-c-JUN signaling pathway. Therefore, miR-3188 might be a potential target for the treatment of NSCLC.

Exonuclease III protection assay with FRET probe for detecting DNA-binding proteins.

We describe a new method for the assay of sequence-specific DNA-binding proteins in this paper. In this method, the sensitive fluorescence resonance energy transfer (FRET) technology is combined with the common DNA footprinting assay in order to develop a simple, rapid and high-throughput approach for quantitatively detecting the sequence-specific DNA-binding proteins. We named this method as exonuclease III (ExoIII) protection assay with FRET probe. The FRET probe used in this assay was a duplex DNA which was designed to contain one FRET pair in the center and two flanking protein-binding sites. During protein detection, if a target protein exists, it will bind to the two protein-binding sites of the FRET probe and thus protect the FRET pair from ExoIII digestion, resulting in high FRET. However, if the target protein does not exist, the FRET pair on the naked FRET probe will be degraded by ExoIII, resulting in low FRET. Three kinds of recombinant transcription factors including NF-kappaB, SP1 and p50, and the target protein of NF-kappaB in HeLa cell nuclear extracts, were successfully detected by the assay. This assay can be extensively used in biomedical research targeted at DNA-binding proteins.

Evaluating the binding affinities of NF-kappaB protein to the single-nucleotide mismatch DNA binding sites by using double-stranded DNA microarray.

Protein-DNA sequence-specific interaction plays an essential role in many biological processes. Here we immobilized a series of double-stranded DNA probes on an agarose coated slide to investigate the binding affinity of NF-kappaB p50 homodimer to the single-nucleotide mismatches (G<-->A or T<-->C) of the 10 base pair (bp) protein binding sites. The results demonstrated that the nucleotides at different positions contribute differently to the p50p50/DNA binding interaction. Within the 10 bp binding sites, the 5tG or 6cA mismatch has less effect on the protein-DNA binding affinity. Even the 5tG mismatch may have the ability to enhance the protein-DNA interaction (5t/w = 1.07). On the other hand, the 7cA or 10tG mismatch blocked the protein-DNA interaction more significantly than other six single-nucleotide mismatches. (7c/W = 0.37, 10t/W = 0.35). It also indicated that the duplex DNA probes immobilized on the agarose-coated surface were apt to be recognized by DNA-binding proteins, and this method would provide a reliable method for exploring the binding affinities of DNA-binding proteins with a larger number of DNA targets.

Accurate identification of closely related Dendrobium species with multiple species-specific gDNA probes.

About 63 species of Dendrobium are identified in China, making the identification of the origin of a particular Dendrobium species on the consumer market very difficult. We report evaluation of multiple species-specific probes screened from genomic DNA for closely related Dendrobium species identification, based on DNA array hybridization. Fourteen species-specific probes were screened from five closely related Dendrobium species, D. aurantiacum Kerr, D. officinale Kimura et Migo, D. nobile Lindl., D. chrysotoxum Lindl. and D. fimbriatum Hook., based on the SSH-Array technology we developed. Various commercial Dendrobium samples and unrelated samples were definitely identified. The specificity and accuracy of the multiple species-specific probes for species identification was assessed by identifying various commercial Dendrobium samples (Herba Dendrobii). Hybridization patterns of these multiple probes on digested genomic DNAs of Dendrobium species indicated that there are distinct polymorphic sequence fragment in the higher eukaryotes. This is the first report on detection and utilization of multiple species-specific probes of Dendrobium in whole genomic DNA, and this could be useful tools not only for a new technical platform for the closely related species identification but also for epidemiological studies on higher eukaryotes.

A free-labeled method for DNA-binding protein detection using a double-stranded DNA microarray.

We have developed a new type of double-stranded DNA microarray to perform detection of sequence-specific DNA-binding proteins. The DNA-binding site of a DNA-binding protein is divided into two fragments. One fragment was immobilized on an aldehyde-coated glass microscope slide surface via chemical bonds. The other fragment was labeled with a fluorescent molecule. When using this kind of double-stranded DNA microarray, the labeled DNA fragment was pre-incubated with detection sample for 5 to 10 minutes and then hybridized with the microarray. In our experiment, six different concentrations of Nuclear Factor kappa-B P50 homodimer in detection samples were tested. The microarray fluorescence intensity was obtained and the relationship between the intensity and the protein concentration was calculated. The detection results suggested that this free-labeled detection system could have the ability to be used in research and medical diagnosis and for high-throughput screening of drugs targeted to DNA-binding proteins.

Optimization of on-chip elongation for fabricating double-stranded DNA microarrays.

The sequence-specific recognitions between DNA and proteins are playing important roles in many biological functions. The double-stranded DNA microarrays (dsDNA microarrays) can be used to study the sequence-specific recognitions between DNAs and proteins in highly parallel way. In this paper, two different elongation processes in forming dsDNA from the immobilized oligonucleotides have been compared in order to optimize the fabrication of dsDNA microarrays: (1) elongation from the hairpins formed by the self-hybridized oligonucleatides spotted on a glass; (2) elongation from the complementary primers hybridized on the spotted oligonucleatides. The results suggested that the dsDNA probes density produced by the hybridized-primer extension was about four times lower than those by the self-hybridized hairpins. Meanwhile, in order to reduce the cost of dsDNA microarrays, we have replaced the Klenow DNA polymerase with Taq DNA polymerase, and optimized the reaction conditions of on-chip elongation. Our experiments showed that the elongation temperature of 50 degrees C and the Mg(2+) concentration of 2.5 mM are the optimized conditions in elongation with Taq DNA polymerase. A dsDNA microarray has been successfully constructed with the above method to detect NF-kB protein.

Investigation of DNA-protein sequence-specific interactions with a ds-DNA array.

The sequence specific recognitions between DNAs and proteins play important roles in many biological functions. The use of double-stranded DNA arrays (ds-DNA arrays) for studying sequence specific recognition between DNAs and proteins is a promising method. Here we report the use of a ds-DNA probe with multi operation sites of restriction proteins in the middle sequence to investigate DNA-protein sequence-specific interactions including methylation. We arranged EcoR I site and Rsa I site on the same duplex DNA probe to fabricate ds-DNA arrays. We used the ds-DNA arrays to study DNA-restriction enzyme reactions before and after duplex DNA methylation under different probe concentration and reaction time conditions. Our results indicated that the ds-DNA arrays can be further biochemically modified and made accessible for interactions between DNAs and proteins in complex multi-step gene-regulation processes.

DNA microarrays with unimolecular hairpin double-stranded DNA probes: fabrication and exploration of sequence-specific DNA/protein interactions.

We have fabricated double-stranded DNA (dsDNA) microarrays containing unimolecular hairpin dsDNA probes immobilized on glass slides. The unimolecular hairpin dsDNA microarrays were manufactured by four steps: Firstly, synthesizing single-stranded DNA (ssDNA) oligonucleotides with two reverse-complementary sequences at 3' hydroxyl end and an overhang sequence at 5' amino end. Secondly, microspotting ssDNA on glutaraldehyde-derived glass slide to form ssDNA microarrays. Thirdly, annealing two reverse-complementary sequences to form hairpin primer at 3' end of immobilized ssDNA and thus to create partial-dsDNA microarray. Fourthly, enzymatically extending hairpin primer to convert partial-dsDNA microarrays into complete-dsDNA microarray. The excellent efficiency and high accuracy of the enzymatic synthesis were demonstrated by incorporation of fluorescently labeled dUTPs in Klenow extension and digestion of dsDNA microarrays with restriction endonuclease. The accessibility and specificity of the DNA-binding proteins binding to dsDNA microarrays were verified by binding Cy3-labeled NF-kappaB to dsDNA microarrays. The dsDNA microarrays have great potential to provide a high-throughput platform for investigation of sequence-specific DNA/protein interactions involved in gene expression regulation, restriction and so on.

[Improved method of treating thoracolumbar burst fracture by posterior pedicle fixation and grafting through injured vertebrae].

OBJECTIVE: To discuss the improved method and effectiveness of posterior pedicle-screw fixation combined with restoring and grafting through the injured vertebrae for treating thoracolumbar burst fracture. METHODS: Between March 2008 and September 2010, 21 patients with thoracolumbar burst fracture were treated by posterior pedicle-screw fixation combined with restoring and grafting through the injured vertebrae. Of 21 cases, 15 were male and 6 were female with an age range of 20-61 years (mean, 38.4 years). Affected segments included T12 in 5 cases, L1 in 7 cases, L2 in 5 cases, and T12-L1 in 4 cases. According to Frankel classification for neurological function, 2 cases were rated as grade A, 4 cases as grade B, 6 cases as grade C, 5 cases as grade D, and 4 cases as grade E; based on Denis classification, all 21 cases were burst fractures, including 7 cases of type A, 11 cases of type B, and 3 cases of type C. The X-ray film was taken to measure the relative height of fractured vertebrae and Cobb's angle, and the function of the spinal cord was evaluated at preoperation, postoperation, and last follow-up. RESULTS: All the incisions healed primarily. The 21 patients were followed up 12-30 months (mean, 26 months). No loosening or breakage of screws and rods occurred. X-ray films showed good bone healing with the healing time from 12 to 23 months (mean, 16 months). The Cobb's angles at 1 week and 1 year postoperatively were (3.4 +/- 2.4) degrees and (5.2 +/- 3.2) degrees respectively, showing significant differences when compared with preoperative angle (22.1 +/- 1.2) degrees (P < 0.05), while no significant difference between 1 week and 1 year after operation (P > 0.05). The anterior height of injured vertebrae recovered from (14.6 +/- 2.1) mm (40.2% +/- 1.5% of the normal) at preoperation to (36.0 +/- 2.0) mm (95.3% +/- 1.3% of the normal) at 1 week, and to (35.0 +/- 2.4) mm (94.4% +/- 2.5% of the normal) at 1 year; significant differences were found between preoperation and postoperation (P < 0.05), while no significant difference between 1 week and 1 year after operation (P > 0.05). At 1 year after operation, the Frankel neurological function grade was improved in varying degrees, showing significant difference when compared with preoperative grade (chi2 = 11.140, P = 0.025). CONCLUSION: Improved method of posterior pedicle-screw fixation combined with restoring and grafting through the injured vertebrae in treatment of thoracolumbar burst fracture can reconstruct the anterior and middle column stability and prevent loss of Cobb's angle and height of vertebrae.