Modeling and Experimental Testing of an Unmanned Surface Vehicle with Rudderless Double Thrusters.

Motion control of unmanned surface vehicles (USVs) is a crucial issue in sailing performance and navigation costs. The actuators of USVs currently available are mostly a combination of thrusters and rudders. The modeling for USVs with rudderless double thrusters is rarely studied. In this paper, the three degrees of freedom (DOFs) dynamic model and propeller thrust model of this kind of USV were derived and combined. The unknown parameters of the propeller thrust model were reduced from six to two. In the three-DOF model, the propulsion of the USV was completely provided by the resultant force generated by double thrusters and the rotational moment was related to the differential thrust. It combined the propeller thrust model to represent the thrust in more detail. We performed a series of tests for a 1.5 m long, 50 kg USV, in order to obtain the model parameters through system identification. Then, the accuracy of the modeling and identification results was verified by experimental testing. Finally, based on the established model and the proportional derivative+line of sight (PD+LOS) control algorithm, the path-following control of the USV was achieved through simulations and experiments. All these demonstrated the validity and practical value of the established model.

Self-Contained High-SNR Underwater Acoustic Signal Acquisition Node and Synchronization Sampling Method for Multiple Distributed Nodes.

Aiming at the application demand in underwater noise monitoring, observation of marine animal, antisubmarine and underwater target localization, a high-SNR underwater acoustic signal acquisition (UASA) node that combines a self-contained acquisition system and floating platform is designed to improve the acquisition performance of a single UASA node, and a high-accuracy synchronization sampling method among multiple distributed UASA nodes based on master-slave dual phase-locked loops (MSDPLL) is proposed to improve the synchronization sampling accuracy. According to the equivalent model of hydrophone and application requirements, low noise signal conditioning circuit and large-capacity data storage modules are designed. Based on the long-term monitoring requirements for underwater acoustic signal and distributed positioning requirements for underwater targets, the structure of a single UASA node is designed and MSDPLL is developed for high-accuracy synchronization sampling among multiple UASA nodes. Related experimental results verified the performance of the UASA node and the synchronization sampling method.

Bio-Inspired Covert Active Sonar Strategy.

The covertness of the active sonar is a very important issue and the sonar signal waveform design problem was studied to improve covertness of the system. Many marine mammals produce call pulses for communication and echolocation, and existing interception systems normally classify these biological signals as ocean noise and filter them out. Based on this, a bio-inspired covert active sonar strategy was proposed. The true, rather than man-made sperm whale, call pulses were used to serve as sonar waveforms so as to ensure the camouflage ability of sonar waveforms. A range and velocity measurement combination (RVMC) was designed by using two true sperm whale call pulses which had excellent range resolution (RR) and large Doppler tolerance (DT). The range and velocity estimation methods were developed based on the RVMC. In the sonar receiver, the correlation technology was used to confirm the start and end time of sonar signals and their echoes, and then based on the developed range and velocity estimation method, the range and velocity of the underwater target were obtained. Then, the RVMC was embedded into the true sperm whale call-train to improve the camouflage ability of the sonar signal-train. Finally, experiment results were provided to verify the performance of the proposed method.

Rapid measurement of spatial light distribution of a short-arc xenon flash lamp.

Small short-arc xenon flash lamps, yielding high energy and ultraviolet radiation without cooling structures, provide ideal analytic-instrument light. Improving instrument designs requires accurately determining spatial optical-flux distribution. Thus, this paper presents rapid scanning of a xenon lamp's central light intensity using a high-sensitivity photodiode to capture short light pulses. Results show two-dimensional optical illumination patterns. In the horizontal mode, the anode and cathode lie in the target plane. In the vertical mode, the two electrodes are centered in a circle. Thus, because the xenon lamp's spatial light flux varies by orientation and main driving voltage, we recommend sampling light horizontally in front of the lamp across small angles.

[Research on Water Quality Analysis Model with PCA Method and UV Absorption Spectra].

Using the UV absorption spectrum to detect Organic pollutants content in water has become one of the most important methods for real-time online monitoring in the field of water quality inspection, however, the water complex and unstable components often bring much uncertain offset to the standard test. In this paper, water samples were classified firstly by analyzing UV absorption spectrum ranging from 200 nm to 400 µm including the organic substances, through the way of combining principal component analysis (PCA) with Euclidean distance. In this paper, we compared the Principal component analysis combined with partial least squares regression (PCA-PLSR) and the direct multi-wavelength absorption models combined with partial least squares regression (MWA-PLSR), not only for the real water sample but also for the analysis of different concentrations of COD standard solution. The result indicates that the measurement errors of the PCA is less than 5%, it is the smallest by using the first and second principal components as regression parameters for PLSR. Using the methods above can simultaneously achieve to classify of water samples and to measure the concentration of water quality parameters more accurately.

Deciphering the pathogenic role of rare RAF1 heterozygous missense mutation in the late-presenting DDH.

Background: Developmental Dysplasia of the Hip (DDH) is a skeletal disorder where late-presenting forms often escape early diagnosis, leading to limb and pain in adults. The genetic basis of DDH is not fully understood despite known genetic predispositions. Methods: We employed Whole Genome Sequencing (WGS) to explore the genetic factors in late-presenting DDH in two unrelated families, supported by phenotypic analyses and in vitro validation. Results: In both cases, a novel de novo heterozygous missense mutation in RAF1 (c.193A>G [p.Lys65Glu]) was identified. This mutation impacted RAF1 protein structure and function, altering downstream signaling in the Ras/ERK pathway, as demonstrated by bioinformatics, molecular dynamics simulations, and in vitro validations. Conclusion: This study contributes to our understanding of the genetic factors involved in DDH by identifying a novel mutation in RAF1. The identification of the RAF1 mutation suggests a possible involvement of the Ras/ERK pathway in the pathogenesis of late-presenting DDH, indicating its potential role in skeletal development.

A Quantitative Anatomic Study of Plate-Screw Fixation of the Acetabular Posterior Column through a Posterior Approach.

OBJECTIVE: The aim of this study was to determine safe paths for screw placement on the posterior column of the acetabulum. METHODS: A total of 25 male hemipelvises were utilized in this study. These hemipelvises were sectioned, and formed cross-sections A, B, C, D, and E. The length of the screw and screw posterior column angle of the entry points at cross-sections B, C, and D were measured. RESULTS: On the margin of the acetabulum, lateral middle 1/4 point, midpoint, medial middle 1/4 point, and medial margin of the posterior column of each cross-section, the safe entry angle of inclination is 39, 57, 74, 90, and 106°, respectively, and the length of the screw is 35.5 mm, 33 mm, 32 mm, 31 mm, and 74 mm, respectively. CONCLUSION: On the lateral 1/4 region, lateral middle 1/4 region, medial middle 1/4 region, and medial 1/4 region of the posterior column, the screw posterior column angle is 40 ~ 60°, 60 ~ 75°, 75 ~ 90°, and 90°~parallel to the quadrilateral plate, respectively, and the length of the screw is 30 mm.

Relationships between stroke, depression, generalized anxiety disorder and physical disability: some evidence from the Canadian Community Health Survey-Mental Health.

The objective of this study is to evaluate associations between stroke, depression, anxiety and physical disability. The sample of 19,159 participants aged ≥30 was obtained from the 2012 Canadian Community Health Survey-Mental Health. Depression or anxiety was defined as major depressive disorder (MDD) or generalized anxiety disorder (GAD) within the past 12 months. The history of anxiety was defined as GAD at any time point during the respondent's lifetime. Physical disability was assessed by the past 14-day disability in daily-living activities. For statistical analysis, two logistic regression models (crude and adjusted models) were presented. The results showed that subjects with stroke had greater likelihoods of MDD-GAD comorbidity and GAD only compared those without stroke. People with GAD only had higher likelihood of physical disability than those with neither of the two conditions. Among participants with stroke, lifetime GAD was associated with a greater likelihood of MDD. In conclusion, individuals with stroke may be vulnerable to comorbid depression-anxiety as well as anxiety only. Additionally, subjects with anxiety were more likely to have physical disability. The history of anxiety increased the risk for developing post-stroke depression.

Down-regulated microRNA-141 facilitates osteoblast activity and inhibits osteoclast activity to ameliorate osteonecrosis of the femoral head via up-regulating TGF-ß2.

Osteonecrosis of the femoral head (ONFH) is a pathological process that initially occurs in the weight-bearing field of the femoral head. Due to the unknown pathogenesis, this study was for the investigation of the effect of microRNA-141 (miR-141) targeting transforming growth factor-ß2 (TGF-ß2) on regulating osteoblast activity and osteoclast activity in steroid-induced ONFH.Tissues of ONFH and normal femoral head were collected for detecting the expression of miR-141 and TGF-ß2. A rat model of ONFH was constructed by injection of hormones, and transfected with miR-141 inhibitors and overexpressed TGF-ß2. The apoptosis of bone cells was detected by TUNEL staining. The expression of osteoprotegerin (OPG), osteoprotegerin ligand (OPGL), Bcl-2, Bax, Runx2, BMP2 and RANK were detected.Highly expressed miR-141 and lowly expressed TGF-ß2 existed in femoral head tissues in ONFH. Inhibited miR-141 resulted in elevated TGF-ß2 in femoral head tissues in ONFH of rats. Depressed miR-141 or overexpressed TGF-ß2 inhibited the apoptosis of bone cells of rats with ONFH and induced elevated OPG, Bcl-2, BMP2, Runx2 and declined OPGL, Bax and RANK expression in the femoral head tissues of rats with ONFH.Altogether, we find that down-regulated miR-141 promotes osteoblast activity and inhibits osteoclast activity to ameliorate ONFH via up-regulated TGF-ß2 expression.

S-Allylmercaptocysteine Targets Nrf2 in Osteoarthritis Treatment Through NOX4/NF-κB Pathway.

PURPOSE: This study aimed to explore the potential role and mechanism of garlic-derived S-allylmercaptocysteine (SAMC), the major water-soluble fraction of garlic, in osteoarthritis (OA) both in vivo and in vitro. METHODS: The effect of SAMC in a surgical-induced OA model was examined by X-ray, staining, ELISA, and immunoblotting. Then the key role of Nrf2 by SAMC treatment in IL-1ß stimulated chondrocytes in vitro was determined by gene-knockdown technique. RESULTS: SAMC could stabilize the extracellular matrix (ECM) by decreasing metalloproteinase (MMPs) expression to suppress type II collagen degradation in OA rats. The inflammatory cytokines, such as IL-1ß, TNF-α, and IL-6, were elevated in OA, which could be down-regulated by SAMC treatment. This effect was parallel with NF-κB signaling inhibition by SAMC. As oxidative stress has been shown to participate in the inflammatory pathways in OA conditions, the key regulator Nrf2 in redox-homeostasis was evaluated in SAMC-treated OA rats. Nrf2 and its down-stream gene NQO-1 were activated in the SAMC-treated group, accompanied by NAD(P)H oxidases 4 (NOX4) expression down-regulated. As a result, the toxic lipid peroxidation byproduct 4-hydroxynonenal (4HNE) was reduced in articular cartilage. In IL-1ß-stimulated primary rat chondrocytes, which could mimic OA in vitro, SAMC could ameliorate collagen destruction, inhibit inflammation, and maintain redox-homeostasis. Interestingly, after Nrf2 gene knockdown by adenovirus, the protective effect of SAMC in IL-1ß-stimulated chondrocytes disappeared. CONCLUSION: Overall, our study demonstrated that SAMC targeted Nrf2 to protect OA both in vivo and in vitro, which would be a new pharmaceutical way for OA therapy.

Quantitative anatomic basis of antegrade lag screw placement in posterior column of acetabulum.

BACKGROUND: Lag screw fixation has been recommended for treatment of acetabular and pelvic fracture for several years. The aim of the present study was to determine the projection of the axis of the posterior column on the inner table of the iliac wing in the supra-acetabular region. METHODS: Thirty adult dried bony hemipelves specimens and other five intact adult dried pelvic specimens were included in this study. The projection point of the axis of the posterior column of the acetabulum was determined on the inner table of the iliac wing of the hemipelves specimens. The perpendicular distance from the optimal entry point to the linea terminalis of pelvis was measured and recorded as the lateral distance. The same measurement along the linea terminalis from the optimal entry point to the junction between the anterior border of iliosacral articulation and the linea terminalis of pelvis was made and recorded as the posterior distance. The depth of the anchor path and the corresponding average retroversion angulation and extraversion angulation were also measured. According to the results acquired from this study, a series of 6.5 mm lag screws were inserted into the posterior column of each side of the other five intact specimens, respectively, to evaluate the position of the screws. The data were expressed as mean +/- SD and analyzed by using the descriptive methods with SPSS 10.0. RESULTS: The average length of lag screw was 104.8 +/- 4.2 mm. The average lateral distance was 16.8 +/- 2.1 mm. The average posterior distance was 23.5 +/- 3.4 mm. The corresponding average retroversion angulation and extraversion angulation were 57 degrees 36' +/- 4 degrees 28' and 119 degrees 18' +/- 2 degrees 32', respectively. The insertion of the single 6.5 mm lag screw of adequate length was possible in the posterior column along its anchor path and no accidental extraosseous or intraarticular screw placement had occurred. CONCLUSIONS: The present study describes a safe anchor path of antegrade lag screw fixation in the posterior column. Insertion of the lag screws of adequate length is possible in the posterior column along its functional axis.

[Clinical anatomic study of internal fixation of acetabular posterior column plate technique].

OBJECTIVES: To study the best entry points, direction and length of screw in acetabular posterior column plate technique, and to prevent the serious complications of screw penetrating the joint surface. METHODS: February to July 2008 20 male cadaveric adult semi-pelvic specimen were taken.Serial cross-sections of the acetabular posterior column were determined and made. The safe angle of screw entry and the length on all entry points of each cross-section were measured. And put all data into software SPSS 10.0 for statistics process. RESULTS: On margin of acetabulum, lateral-middle 1/4 point, midpoint, medial-middle 1/4 point and medial margin of posterior column of each cross-section, safe entry angle of inclination was 39 degrees , 57 degrees , 74 degrees , 90 degrees and 106 degrees respectively, the length of the screw was 39, 57, 74, 90 and 106 mm respectively. CONCLUSION: On lateral 1/4 region, lateral-middle 1/4 region, medial-middle 1/4 region and medial 1/4 region, screw posterior column angle is 40 degrees to 60 degrees , 60 degrees to 75 degrees , 75 degrees to 90 degrees , 90 degrees to parallel to the quadrilateral plate, and the length of the screw is 30 mm.

The relationship between genetic polymorphisms in apolipoprotein E (ApoE) gene and osteonecrosis of the femoral head induced by steroid in Chinese Han population.

Previous studies suggested that apolipoprotein E (ApoE) genetic polymorphisms (SNPs) may result in abnormal lipid metabolism. Therefore, genetic polymorphisms in ApoE may be associated with the occurrence of osteonecrosis of the femoral head (ONFH). A case control study was designed to include 580 patients with steroid-induced ONFH and 560 age- and sex-matched non steroid-induced ONFH control subjects to analyze the association between ApoE polymorphisms and susceptibility of steroid-induced ONFH. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was utilized to differentiate two genotypes SNPs (rs7412 C/T and rs429358 T/C) in ApoE gene. Both rs7412 C/T and rs429358 T/C were found to be associated with the risk of steroid-induced ONFH. However, no significant association was observed between the haplotypes T-T, T-C and C-C in ONFH. Furthermore, T allele of rs7412 and C allele of rs429358 carriers were associated with higher levels of TG in steroid-induced ONFH patients (P < 0.05). The study suggested that ApoE genetic polymorphisms conferred susceptibility to steroid-induced ONFH in Chinese Han population. However, the results need further investigation with large sample size and various populations.

Inhibitory effect of quercetin on titanium particle-induced endoplasmic reticulum stress (ERS)-related apoptosis and in vivoosteolysis.

Wear particle-induced periprosthetic osteolysis is the main cause of aseptic loosening of orthopaedic implants. The aim of this study is to determine the protective effect of quercetin (QUE) against titanium (Ti) particle-induced ERS-related apoptosis and osteolysis. In this study, RAW264.7 cells were pretreated with different concentrations (40, 80, and 160 µmol/l) of QUE for 30 min and then treated with Ti particle (5 mg/ml) for 24 h. Cell viability and apoptosis were determined using MTT assay and Annexin V-FITC apoptosis detection kit, respectively. Protein and mRNA expressions of ERS-related genes were examined by western blot and real-time PCR, respectively. The release of inflammatory cytokines was detected by ELISA. Then a mouse calvarial osteolysis model was established. Histological sections of calvaria were stained with H&E or TRAP. The results showed that Ti particle reduced cell viability and induced apoptosis in RAW264.7 macrophages. The cytotoxic effects of Ti particle were dramatically inhibited by QUE pretreatment. Interestingly, we found that QUE also significantly reduced Ti particle-induced up-regulation of the expression levels of PERK, IRE1, GRP78, CHOP, caspase-12 and caspase-3 and enhanced the down-regulation of Bcl-2. In addition, QUE decreased Ti particle-induced inflammatory cytokines release from RAW264.7 cells. Moreover, treatment with QUE markedly decreased osteoclast number. In a mouse calvarial osteolysis model, QUE inhibited Ti particle-induced osteolysis in vivo by inhibiting osteoclast formation and expressions of ERS-related genes. In conclusion, QUE can protect RAW264.7 cells from Ti particle-induced ERS-related apoptosis and suppress calvarial osteolysis in vivo.

Calcitonin protects chondrocytes from lipopolysaccharide-induced apoptosis and inflammatory response through MAPK/Wnt/NF-κB pathways.

Calcitonin (CT) is an anti-absorbent, which has long been used for treatment of osteoporosis. However, little information is available about the effects of CT on osteoarthritis (OA). This study was mainly aimed to explore the effects of CT on the treatment of OA, as well as the underlying mechanisms. Chondrocytes were isolated from immature mice and then were incubated with lipopolysaccharide (LPS), CT, small interfering (si) RNA against bone morphogenetic protein (BMP)-2, and/or the inhibitors of MAPK/Wnt/NF-κB pathway. Thereafter, cell viability, apoptosis, nitric oxide (NO) and inflammatory factors productions, and expression levels of cartilage synthesis protein key factors, cartilage-derived morphogenetic protein (CDMP) 1, SRY (sex-determining region Y)-box 9 protein (SOX9), and MAPK/Wnt/NF-κB pathways key factors were determined. CT significantly reversed LPS-induced cell viability decrease, apoptosis increase, the inflammatory factors and NO secretion, the abnormally expression of cartilage synthesis proteins and the activation of MAPK/Wnt/NF-κB pathways (P<0.05). In addition, we observed that administration of the inhibitors of MAPK/Wnt/NF-κB pathways statistically further increased the levels of CDMP1 and SOX9 (P<0.05). Suppression of BMP-2 decreased the levels of CDMP1 and SOX9 and activated MAPK/Wnt/NF-κB pathways, and could partially abolish CT-modulated the expression changes in CDMP1 and SOX9, and MAPK/Wnt/NF-κB pathways key factors (P<0.05). The results showed that CT protects chondrocytes from LPS-induced apoptosis and inflammatory response by regulating BMP-2 and thus blocking MAPK/Wnt/NF-κB pathways.

Effect of Scutellarin inhibits collagen­induced arthritis through TLR4/NF­κB­mediated inflammation.

Scutellarin is the major effective constituent of the commonly used Chinese medicine Erigeron breviscapus. It has been applied in the clinic to treat various diseases, and is characterized by high content, a stable source, controllable quality, high efficiency and low toxicity. In addition, its potential pharmacological effects have been increasingly identified and elucidated. The present study was performed to examine the role of scutellarin on collagen­induced arthritis (CIA). Mice were injected subcutaneously with bovine collagen type II and administered scutellarin for 2 weeks by gavage 20 mg/kg/day. ELISA kits were used to measure the levels of interleukin (IL)­1ß, IL­6, tumor necrosis factor­α (TNF­α), oxidative stress markers [superoxide dismutase (SOD) and malondialdehyde (MDA)] and caspase­3/-9 activity. Bax, Bcl­2, toll like receptor 4 (TLR4) and nuclear factor (NF)­κB protein expression was analyzed using western immunoblot analyses. The present study demonstrated that scutellarin prevented CIA, and inhibited the expression of inflammation factors, IL­1ß, IL­6 and TNF­α. In addition, scutellarin reduced the levels of oxidative stress markers, SOD and MDA, as well as intercellular adhesion molecule­1 and monocyte chemoattractant protein 1 in CIA mice. Caspase­3/-9, Bax/Bcl­2, TLR4 and NF­κB protein expression were reduced in CIA mice following scutellarin treatment. The results of the current study suggest a novel effect of scutellarin involving the inhibition of TLR4/NF­κB­mediated inflammation.

[Anatomic study of internal fixation of acetabular anterior column plate technique].

OBJECTIVE: To study the best entry points, direction and length of screw in acetabular anterior column plate technique, and to prevent the serious complications of screw penetrating the joint surface. METHODS: Twenty male cadaveric adult semi-pelvic specimen were taken, and the distance from anterior acetabular margin, posterior acetabular margin to anterior inferior iliac spine, iliopubic eminence and pubic tubercle were measured respectively. Determine and make serial cross-sections of the acetabular anterior column, measure the safe angle of screw entry on all entry points of each cross-section, and put all data into software SPSS 10.0 for statistics process. RESULTS: The distance from anterior acetabular margin to anterior inferior iliac spine, iliopubic eminence and pubic tubercle was (25.4 +/- 1.4) mm, (11.8 +/- 0.7) mm and (37.4 +/- 1.5) mm respectively, the distance from posterior acetabular margin to anterior inferior iliac spine, iliopubic eminence was (15.5 +/- 0.9) mm and (29.1 +/- 1.6) mm respectively. On each cross-section, the maximum of the safe entry angle of inclination in 0.5 cm, 1.0 cm and 1.5 cm entry point lateral to the linea terminalis of pelvis was (8.2 +/- 2.2) degrees , (14.9 +/- 3.4) degrees and (26.1 +/- 4.5) degrees respectively. CONCLUSIONS: When plate for internal fixation on acetabular region of anterior column is used, there are three ways to avoid screw penetrating the joint surface. The first way is using short screw in any direction; the second way is using long screw close to the linea terminalis of pelvis, the direction of the screw is parallel to the quadrilateral plate; the third way is using different entry angle and length according to different entry point.

Tobacco smoke induces production of chemokine CCL20 to promote lung cancer.

Tobacco kills nearly 6 million people each year, and 90% of the annual 1.59 million lung cancer deaths worldwide are caused by cigarette smoke. Clinically, a long latency is required for individuals to develop lung cancer since they were first exposed to smoking. In this study, we aimed to identify clinical relevant inflammatory factors that are critical for carcinogenesis by treating normal human lung epithelial cells with tobacco carcinogen nicotine-derived nitrosaminoketone (NNK) for a long period (60 days) and systematic screening in 84 cytokines/chemokines. We found that a chemokine CCL20 was significantly up-regulated by NNK, and in 78/173 (45.1%) patients the expression of CCL20 was higher in tumor samples than their adjacent normal lung tissues. Interestingly, CCL20 was up-regulated in 48/92 (52.2%) smoker and 29/78 (37.2%) nonsmoker patients (p = 0.05), and high CCL20 was associated with poor prognosis. NNK induced the production of CCL20, which promoted lung cancer cell proliferation and migration. In addition, an anti-inflammation drug, dexamethasone, inhibited NNK-induced CCL20 production and suppressed lung cancer in vitro and in vivo. These results indicate that CCL20 is crucial for tobacco smoke-caused lung cancer, and anti-CCL20 could be a rational approach to fight against this deadly disease.