Evaluation of neurotoxicity and the role of oxidative stress of cobalt nanoparticles, titanium dioxide nanoparticles, and multiwall carbon nanotubes in Caenorhabditis elegans.

The widespread use of nanomaterials in daily life has led to increased concern about their potential neurotoxicity. Therefore, it is particularly important to establish a simple and reproducible assessment system. Representative nanomaterials, including cobalt nanoparticles (CoNPs), titanium dioxide nanoparticles (TiO2-NPs), and multiwall carbon nanotubes (MWCNTs), were compared in terms of their neurotoxicity and underlying mechanisms. In 0, 25, 50, and 75 µg/ml of these nanomaterials, the survival, locomotion behaviors, acetylcholinesterase (AchE) activity, reactive oxygen species production, and glutathione-S transferase 4 (Gst-4) activation in wildtype and transgenic Caenorhabditis elegans (C. elegans) were evaluated. All nanomaterials induced an imbalance in oxidative stress, decreased the ratio of survival, impaired locomotion behaviors, as well as reduced the activity of AchE in C. elegans. Interestingly, CoNPs and MWCNTs activated Gst-4, but not TiO2-NPs. The reactive oxygen species scavenger, N-acetyl-l-cysteine, alleviated oxidative stress and Gst-4 upregulation upon exposure to CoNPs and MWCNTs, and rescued the locomotion behaviors. MWCNTs caused the most severe damage, followed by CoNPs and TiO2-NPs. Furthermore, oxidative stress and subsequent activation of Gst-4 were involved in nanomaterials-induced neurotoxicity. Our study provides a comprehensive comparison of the neurotoxicity and mechanisms of typical nanomaterials, which could serve as a model for hazard assessment of environmental pollutants using C. elegans as an experimental model system.

Smart Vehicle Path Planning Based on Modified PRM Algorithm.

Path planning is a very important step for mobile smart vehicles in complex environments. Sampling based planners such as the Probabilistic Roadmap Method (PRM) have been widely used for smart vehicle applications. However, there exist some shortcomings, such as low efficiency, low reuse rate of the roadmap, and a lack of guidance in the selection of sampling points. To solve the above problems, we designed a pseudo-random sampling strategy with the main spatial axis as the reference axis. We optimized the generation of sampling points, removed redundant sampling points, set the distance threshold between road points, adopted a two-way incremental method for collision detections, and optimized the number of collision detection calls to improve the construction efficiency of the roadmap. The key road points of the planned path were extracted as discrete control points of the Bessel curve, and the paths were smoothed to make the generated paths more consistent with the driving conditions of vehicles. The correctness of the modified PRM was verified and analyzed using MATLAB and ROS to build a test platform. Compared with the basic PRM algorithm, the modified PRM algorithm has advantages related to speed in constructing the roadmap, path planning, and path length.

The Intrinsic Thermodynamic Difficulty and a Step-Guided Mechanism for the Epitaxial Growth of Uniform Multilayer MoS2 with Controllable Thickness.

Multilayer MoS2 shows superior performance over the monolayer MoS2 for electronic devices while the growth of multilayer MoS2 with controllable and uniform thickness is still very challenging. It is revealed by calculations that monolayer MoS2 domains are thermodynamically much more favorable than multilayer ones on epitaxial substrates due to the competition between surface interactions and edge formation, leading accordingly to a layer-by-layer growth pattern and non-continuously distributed multilayer domains with uncontrollable thickness uniformity. The thermodynamics model also suggests that multilayer MoS2 domains with aligned edges can significantly reduce their free energy and represent a local minimum with very prominent energy advantage on a potential energy surface. However, the nucleation probability of multilayer MoS2 domains with aligned edges is, if not impossible, extremely rare on flat substrates. Herein, a step-guided mechanism for the growth of uniform multilayer MoS2 on an epitaxial substrate is theoretically proposed. The steps with proper height on sapphire surface are able to guide the simultaneous nucleation of multilayer MoS2 with aligned edges and uniform thickness, and promote the continuous growth of multilayer MoS2 films. The proposed mechanism can be reasonably extended to grow multilayer 2D materials with uniform thickness on epitaxial substrates.

MicroRNA-142 regulates osteoblast differentiation and apoptosis of mouse pre-osteoblast cells by targeting bone morphogenetic protein 2.

Osteoporosis is a common disease that can seriously impair the physical and mental health of the elderly. However, current treatment is unsatisfactory due to the lack of effective therapeutic targets. Abnormal expression and involvement of microRNA-142 (miR-142) have been identified in many diseases, including bone-related diseases. Herein, we explored the effect of miR-142 on the viability, differentiation and apoptosis of the mouse preosteoblast cell line MC3T3-E1. We observed that the viability of MC3T3-E1 cells was significantly inhibited or promoted after transfection of miR-142 mimic or inhibitor, respectively. The apoptotic rate was dramatically increased by miR-142 mimic and decreased by inhibitor compared with the negative control group. Bcl-2 expression was down-regulated in the miR-142 mimic group and up-regulated in the miR-142 inhibitor group, whereas levels of cleaved caspase-3 and Bax were increased in the miR-142 mimic group and reduced in the miR-142 inhibitor group. Expression changes of Runx2 and Osteocalcin suggest that miR-142 inhibits the differentiation of osteoblast cells. Moreover, the luciferase reporter assay was used to verify that bone morphogenetic protein 2 (BMP2) is a target of miR-142. Overexpression of BMP2 repressed the proapoptotic effect of miR-142 mimic, whereas knockdown of BMP2 abolished the inhibitory effect of miR-142 inhibitor on the apoptosis of MC3T3-E1 cells. Furthermore, up-regulation or down-regulation of miR-142 dramatically decreased or increased the ratio of p-Smad1/5/Smad1 and p-Smad1/5/Smad5, respectively. Collectively, our results imply that miR-142 might influence the viability and differentiation of osteoblast cells by regulating BMP2 and BMP/Smad signaling.

Clinical outcomes of revision with retrograde intermedullary nailing for failed plating of distal femoral fractures: a retrospective study.

PURPOSE: To assess the feasibility and effectiveness of retrograde intramedullary nail (RIN) revision surgeries for locking compression plate (LCP) failure in distal femoral fractures. METHODS: This retrospective study included 13 patients who suffered from metalwork failures after they initially underwent open reduction and LCP fixation. In patients who eventually underwent RIN revision from January 2014 to December 2016, range of motion (ROM) and Hospital for Special Surgery (HSS) scores obtained before surgery and at the final follow-up time were analysed. RESULTS: The average operative time was 155 minutes (range, 120-210 minutes), and the average blood loss volume was 650 ml (range, 200-1350 ml). There were two cases of complications (15.38%): one was calf muscle vein thrombosis, and the other was a superficial infection. No deep tissue infection or deep vein thrombosis was observed post-operatively. The average follow-up time was 16 months (range, 12-24 months). All fractures healed in a mean of 6.5 months (range, 4-12 months), and one patient underwent an additional bone graft surgery that did not involve a bone graft during the RIN revision operation (this eventually healed at 12 months post-operatively). The mean ROM before the operation was 86.92 ± 12.34°. At the final follow-up, the mean ROM was 112.69 ± 9.27°. There was a significant difference between pre-operative and post-operative ROM (P < 0.01). The mean HSS score improved significantly from 38.85 ± 9.62 points pre-operatively to 79.62 ± 5.42 points post-operatively. There was a significant difference between pre-operative and post-operative HSS scores (P < 0.01). CONCLUSIONS: RIN revision surgery achieved excellent clinical results in patients with LCP failure.

[Treatment of Day type â ¡ pelvic crescent fracture by using percutaneous cannulated screw fixation technique].

Objective: To evaluate the feasibility and effectiveness of percutaneous cannulated screw fixation for the treatment of Day type Ⅱ pelvic crescent fracture. Methods: The clinical data of 14 patients with Day type Ⅱ pelvic crescent fractures underwent closed reduction and percutaneous cannulated screw fixation between January 2009 and July 2016 were retrospectively analysed. There were 9 males and 5 females, aged 17-65 years (mean, 38 years). The causes of injury included traffic accident in 8 cases, falling from height in 3 cases, bruise injury in 3 cases; all were closed fractures. According to Tile classification, there were 8 cases of type B, 6 cases of type C. There were 13 cases combined with fracture of the anterior pelvic ring, including 8 cases of superior and inferior ramus of pubis fracture, 1 case of superior ramus of pubis fracture with symphysis separation, and 4 cases of symphysis separation. The interval of injury and admission was 1- 72 hours (mean, 16 hours), and the interval of injury and operation was 3-8 days (mean, 5 days). After operation, the reduction of fracture was evaluated by the Matta evaluation criteria, the clinical function was assessed by Majeed function assessment. Results: The operation time was 35-95 minutes (mean, 55 minutes), cumulative C-arm fluoroscopy time was 3-8 minutes (mean, 5 minutes), no iatrogenic vascular injury and pelvic organ damage occurred. Postoperative X-ray films at 2 days indicated that 2 cases of vertical shift and 2 cases of mild rotation were not completely corrected. Postoperative CT examination at 3 days indicated that 2 pubic joint screws broke through the obturator bone cortex. None of the pubic ramus screws entered into the acetabulum, but a screw of superior pubic branch broke through the posterior cortical of superior pubic branch, a screw of posterior ilium column broke through the medial bone cortex of the ilium, and no clinical symptom was observed. One patient suffered from wound infection in the pubic symphysis, then healed after 2 weeks of wound drainage, the other wounds healed by first intention. According to Matta criterion for fracture reduction, the results were excellent in 9 cases, good in 4 cases, and fair in 1 case with an excellent and good rate of 92.9%. All patients were followed up 8-24 months (mean, 14 months). All fractures healed at 4 months and restored to the normal walking at 6 months after operation, 3 patients suffered from slight pain in the sacroiliac joints and slight claudication when they were tired or walked for a long time and unnecessary for special treatment. One patient felt pain in the back of the iliac spine when he was lying down. During the follow-up, no screw loosening or other internal fixation failure occurred. At last follow-up, according to Majeed functional evaluation criteria, the results were excellent in 7 cases, good in 5 cases, and fair in 2 cases with an excellent and good rate of 85.7%. Conclusion: The percutaneous cannulated screw fixation is a safe treatment for Day type Ⅱ pelvic crescent fracture, which has a reliable fixation and good effectiveness.

[Clinical analysis of thyroid associated ophthalmopathy with myasthenia Graves in 12 patients].

OBJECTIVE: To summarized the clinical features of thyroid associated ophthalmopathy patients with myasthenia gravis. METHODS: This is a retrospective case series study. The clinical data of 12 thyroid associated ophthalmopathy patients with myasthenia gravis were collected in the 416 Hospital of Nuclear Industry from Oct. 2012 to Feb. 2014. All patients had a detailed medical history including symptoms of onset, the best corrected visual acuity, anterior and posterior segment examination, the exophthalmos, eyelid position, eye movement, diplopia, strabismus, systemic symptoms, concurrent fatigue test, neostigmine test, thyroid function and orbital CT scan. One patient underwent CT examination of thymus. RESULTS: In all 12 patients, there were 8 females and 4 males with age from 13.0 to 44.0 years (the median age of 26.5 years), 11 cases had difficulties to open their eyes which was least severe in the morning and worsened in the evening. All of cases did not have general symptoms. Ptosis was observed in 9 cases, 3 cases were bilateral, and 6 cases were unilateral. Abnormal extra ocular muscle function was observed in 8 cases, all of them were bilateral. In these 16 eyes, the limitation of downward gaze were observed in 15 eyes, the limitation of upward, outward and inward gaze were observed in 14 eyes, eye fixation occurred in 4 eyes. Four cases had diplopia, 3 cases had strabismus, and 2 of them were exotropia. Orbital CT demonstrated extraocular muscle thickening in 6 cases. Thickening of inferior rectus were observed in all 12 eyes, superior rectus and medial rectus were found thickened in 6 eyes, and thickening of lateral rectus muscle was found in 3 eyes. CONCLUSIONS: The clinical features of thyroid associated ophthalmopathy patients with myasthenia gravis were complex. When ptosis and eye movement disorders were not consistent with TAO severity, associating with exotropia and systemic muscle paralysis, myasthenia gravis should be considered.

[Experimental study on three repairing methods for femoral nerve injury after ligation in rats].

OBJECTIVE: To investigate the effects of 3 methods (suture removal, suture removal with epineurium neurolysis, and ligated femoral nerve resection with end-end suture) in repairing femoral nerve injury after ligation in different periods so as to provide a reference for clinical use of repairing iatrogenic ligation injury of the peripheral nerve. METHODS: A total of 120 adult female Sprague Dawley rats, weighing (200 +/- 20) g, were used to prepare the animal models of left femoral nerve ligation, and were divided into groups A (n=40), B (n=40), and C (n=40) according different repairing methods. At immediate, 1, 3, and 5 months (10 rats each time point) after ligation, suture removal was performed in group A, suture removal with epineurium neurolysis in group B, and ligated femoral nerve resection with end-end suture in group C. At 3 months after operation, the foot-base angle (FBA) and the heels-tail angle (HTA), action potential and conduction velocity of femoral nerve, and wet weight of quadriceps femoris muscle (QFM) were measured; the samples of quadriceps femoris and femoral nerve were harvested for histological observation, muscle fiber count, and nerve fiber passing rate measuring. RESULTS: The FBA in group A was significant smaller than that in group C at immediate, 1, 3, and 5 months (P < 0.05), but there was no significant difference between groups A and B (P > 0.05). The HTA in group A was significantly smaller than that in group C at immediate, 1, 3, and 5 months (P < 0.05), and the THA in group B was significantly smaller than that in group C at 1, 3, and 5 months (P < 0.05). The wet weight of QFM in group B was significantly higher than that in group C at immediate, 3, and 5 months (P < 0.05), and the wet weight of QFM in group A was significantly higher than that in group C at immediate and 3 months (P < 0.05), but no significant difference was found between groups A and B at immediate, 1, and 3 months (P > 0.05). There was significant difference in the action potential of femoral nerve between group A and groups B and C at immediate and 1 month (P < 0.05), but there was no significant difference between other groups at 3 and 5 months (P > 0.05) except between groups A and C at 5 months (P < 0.05). The conduction velocity of femoral nerve in group A was significantly faster than that in group C at immediate, 1, and 5 months (P < 0.05), and it was significantly faster in group A than in group B at immediate and 1 month (P < 0.05), but no significant difference was found between groups A and B at 3 and 5 months (P > 0.05), between groups B and C at other time points (P > 0.05) except at immediate (P < 0.05). The count of muscle fibre of the quadriceps femoris was significantly more in groups A and B than in group C at immediate (P < 0.05); it was significantly more in group A than in group B at 5 months (P < 0.05). The passing rate of the femoral nerve fiber was significantly higher in group A than in groups B and C at 3 months (P < 0.05), but no significant difference was found between the other groups (P > 0.05). CONCLUSION: After femoral nerve ligation, suture removal method has the best effect at early term, the next is epineurium neurolysis method, and the worst is the ligation femoral nerve resection with end-end suture repair.