The identification, adaptive evolutionary analyses and mRNA expression levels of homeobox (hox) genes in the Chinese mitten crab Eriocheir sinensis.

BACKGROUND: Arthropods are the largest group in the animal kingdom and are morphologically characterized by heterorhythmic segments. Brachyuran decapod crustaceans undergo brachyurization metamorphosis in the early developmental process, characterized by a reduced abdomen that is folded beneath the cephalothorax and inserted between the pereiopods or in a special cavity. As the main cause of major alterations in the evolution of animal body plans, Hox genes encode transcription factors and are involved in bilaterian anterior-posterior axis patterning. RESULTS: We found eight Hox genes (labial, proboscipedia, Deformed, zerknüllt, Sex combs reduced, Antennapedia, Ultrabithorax, fushi tarazu, abdominal-A and Abdominal-B) in Eriocheir sinensis. The phylogenetic topology of 13 arthropod Hox genes was closely related to traditional taxonomic groupings. Genome collinearity analysis was performed using genomic data and chromosomal location data of E. sinensis and Portunus trituratus. We found that their chromosomes were highly collinear, and there was a corresponding collinear relationship between the three Hox genes (lab, ftz and Abd-B). The mRNA expression levels of Scr and Antp fluctuated significantly in different developmental stages of E. sinensis, especially in the brachyurization stages. Evolutionary analysis indicated the presence of positively selected sites in Ubx. CONCLUSIONS: In this study, we used genome-wide analysis to identify and analyze all members of the Hox genes in E. sinensis. Our data will contribute to a better understanding of Hox genes in E. sinensis and provide useful molecular evolutionary information for further investigation on their roles in the brachyurization of crabs.

Biomechanical analysis of maxillary anterior teeth movements during different retracting methods with a lever arm miniscrew system in double-slot lingual brackets: A finite element method study.

OBJECTIVE: The objective of the study was to find the most effective retracting method for the six maxillary anterior teeth with double-slot lingual brackets using a lever arm and miniscrew system. METHODS: Six finite element models were constructed: (A) a ribbon-wise archwire with a lever arm; (B) a ribbon-wise archwire with a lever arm and a sectional edgewise archwire; (C) a ribbon-wise archwire and a sectional edgewise archwire with a lever arm; (D) an edgewise archwire with a lever arm; (E) an edgewise archwire with a lever arm and a sectional ribbon-wise archwire; and (F) an edgewise archwire and a sectional ribbon-wise archwire with a lever arm. Initial displacements of maxillary teeth driven by a 1.5 N retraction force to the lever arm were analysed. RESULTS: In models B, C, E and F, anterior torque loss and inter-canine distance increases were significantly lower than that of the models without auxiliary archwires. In models C and F, the main archwire was less likely deformed. In models A, B and C, the displacement of canines in sagittal and vertical directions were less than in models D, E and F. CONCLUSIONS: The combination of edgewise and ribbon-wise archwires in double-slot lingual brackets effectively preserves the anterior arch shape. An edgewise archwire with lever arms on the auxiliary sectional ribbon-wise archwire is recommended for better performance in anterior teeth retraction.

[Accurate tissue flap reconstruction method based on the quadratic surface developability for head and neck soft tissue defects].

Soft tissue defects resulting from head and neck tumor resection seriously impact the physical appearance and psychological well-being of patients. The complex curvature of the human head and neck poses a formidable challenge for maxillofacial surgeons to achieve precise aesthetic and functional restoration after surgery. To this end, a normal head and neck volunteer was selected as the subject of investigation. Employing Gaussian curvature analysis, combined with mechanical constraints and principal curvature analysis methods of soft tissue clinical treatment, a precise developable/non-developable area partition map of the head and neck surface was obtained, and a non-developable surface was constructed. Subsequently, a digital design method was proposed for the repair of head and neck soft tissue defects, and an in vitro simulated surgery experiment was conducted. Clinical verification was performed on a patient with tonsil tumor, and the results demonstrated that digital technology-designed flaps improved the accuracy and aesthetic outcome of head and neck soft tissue defect repair surgery. This study validates the feasibility of digital precision repair technology for soft tissue defects after head and neck tumor resection, which effectively assists surgeons in achieving precise flap transplantation reconstruction and improves patients' postoperative satisfaction.

Phosphorothioated and phosphate-terminal dumbbell (PP-TD) probe-based rapid detection of polynucleotide kinase activity.

Polynucleotide kinase (PNK), a bifunctional enzyme with 5'-kinase and 3'-phosphatase activities, plays an important role in DNA repair and is associated with various diseases. Here, we developed a primer-free, sensitive, and isothermal quantitative assay to detect PNK activity. In the presence of PNK, the 3'-phosphate group of the substrate was digested with 3'-OH, initiating the amplification reaction. Elongated dsDNA binds to the dsDNA-specific fluorescent dye EvaGreen, leading to a significant enhancement in fluorescence intensity. The limit of detection (LOD) of this method was 7.7 × 10-7 U µL-1, which is comparable or even superior to that of previously reported methods. This approach also showed good quantitative ability in complex cell lysates, indicating potential for biological sample analysis. Additionally, this facile and sensitive assay can be used to screen for PNK inhibitors. The proposed method provides a promising platform for sensitive PNK activity monitoring and inhibition screening for drug discovery and clinical treatment.

Experimental validation of finite element simulation of a new custom-designed fixation plate to treat mandibular angle fracture.

BACKGROUND: The objective of the study was to validate biomechanical characteristics of a 3D-printed, novel-designated fixation plate for treating mandibular angle fracture, and compare it with two commonly used fixation plates by finite element (FE) simulations and experimental testing. METHODS: A 3D virtual mandible was created from a patient's CT images as the master model. A custom-designed plate and two commonly used fixation plates were reconstructed onto the master model for FE simulations. Modeling of angle fracture, simulation of muscles of mastication, and defining of boundary conditions were integrated into the theoretical model. Strain levels during different loading conditions were analyzed using a finite element method (FEM). For mechanical test design, samples of the virtual mandible with angle fracture and the custom-designed fixation plates were printed using selective laser sintering (SLS) and selective laser melting (SLM) printing methods. Experimental data were collected from a testing platform with attached strain gauges to the mandible and the plates at different 10 locations during mechanical tests. Simulation of muscle forces and temporomandibular joint conditions were built into the physical models to improve the accuracy of clinical conditions. The experimental vs the theoretical data collected at the 10 locations were compared, and the correlation coefficient was calculated. RESULTS: The results show that use of the novel-designated fixation plate has significant mechanical advantages compared to the two commonly used fixation plates. The results of measured strains at each location show a very high correlation between the physical model and the virtual mandible of their biomechanical behaviors under simulated occlusal loading conditions when treating angle fracture of the mandible. CONCLUSIONS: Based on the results from our study, we validate the accuracy of our computational model which allows us to use it for future clinical applications under more sophisticated biomechanical simulations and testing.

Excellent diagnostic performance of FNA-Tg in detecting lymph nodes metastases from papillary thyroid cancer.

Background: Thyroglobulin washout of fine needle aspiration (FNA-Tg) has proved to be useful in detecting lymph node metastases from papillary thyroid cancer; however, the influences of thyroid gland, Hashimoto thyroiditis, serum thyroglobulin (Tg) and anti-TG antibody on the diagnostic performance of FNA-Tg are controversial. Patients & methods: We retrospectively collected the FNA-Tg results of 176 preoperative or postoperative patients (356 lymph nodes) who finally were diagnosed with papillary thyroid cancer. The diagnostic abilities of FNA-Tg were evaluated and compared under different circumstances. Results: The diagnostic performance of FNA-Tg was uninfluenced irrespective of the status of thyroid gland or serum anti-TG antibody. However, high serum Tg was positively correlated with FNA-Tg (Exp(B) = 1.57; 95% CI: 1.209-2.309; p = 0.001). Conclusion: FNA-Tg was an excellent diagnostic tool, but it should be interpreted with caution only if serum Tg is higher than 10 ng/ml.

Meta-analysis reveals severe pollen limitation for the flowering plants growing in East Himalaya-Hengduan Mountains region.

BACKGROUND: Pollen limitation occurs widely and has an important effect on flowering plants. The East Himalaya-Hengduan Mountains region is a global biodiversity hotspot. However, to our knowledge, no study has synthetically assessed the degree of pollen limitation in this area. The present study aims to reveal the degree of pollen limitation for the flowering plants growing on East Himalaya-Hengduan Mountains and to test whether the reproductive features or the elevation is closely correlated with the degree of pollen limitation in this area. RESULTS: We complied data from 76 studies, which included 96 species and 108 independent data records. We found that the flowering plants in this area undergo severe pollen limitation [overall Hedges' d = 2.004, with a 95% confidence interval (1.3264, 2.6743)] that is much higher than that of the flowering plants growing in many other regions around the world. The degree of pollen limitation was tested to determine the correlation with the capacity for autonomous self-reproduction and with the pollination pattern (generalized vs. specialized pollination) of plants. In addition, we found a clear relationship between elevation and the degree of pollen limitation, which indicates that plants might undergo more severe pollen limitation in relatively high places. CONCLUSIONS: This paper is the first to address the severe pollen limitation of the flowering plants growing in East Himalaya-Hengduan Mountains region. Moreover, we reveal the positive correlation between elevation and the degree of pollen limitation.

A customized fixation plate with novel structure designed by topological optimization for mandibular angle fracture based on finite element analysis.

BACKGROUND: The purpose of this study was to design a customized fixation plate for mandibular angle fracture using topological optimization based on the biomechanical properties of the two conventional fixation systems, and compare the results of stress, strain and displacement distributions calculated by finite element analysis (FEA). METHODS: A three-dimensional (3D) virtual mandible was reconstructed from CT images with a mimic angle fracture and a 1 mm gap between two bone segments, and then a FEA model, including volume mesh with inhomogeneous bone material properties, three loading conditions and constraints (muscles and condyles), was created to design a customized plate using topological optimization method, then the shape of the plate was referenced from the stress concentrated area on an initial part created from thickened bone surface for optimal calculation, and then the plate was formulated as "V" pattern according to dimensions of standard mini-plate finally. To compare the biomechanical behavior of the "V" plate and other conventional mini-plates for angle fracture fixation, two conventional fixation systems were used: type A, one standard mini-plate, and type B, two standard mini-plates, and the stress, strain and displacement distributions within the three fixation systems were compared and discussed. RESULTS: The stress, strain and displacement distributions to the angle fractured mandible with three different fixation modalities were collected, respectively, and the maximum stress for each model emerged at the mandibular ramus or screw holes. Under the same loading conditions, the maximum stress on the customized fixation system decreased 74.3, 75.6 and 70.6% compared to type A, and 34.9, 34.1, and 39.6% compared to type B. All maximum von Mises stresses of mandible were well below the allowable stress of human bone, as well as maximum principal strain. And the displacement diagram of bony segments indicated the effect of treatment with different fixation systems. CONCLUSIONS: The customized fixation system with topological optimized structure has good biomechanical behavior for mandibular angle fracture because the stress, strain and displacement within the plate could be reduced significantly comparing to conventional "one mini-plate" or "two mini-plates" systems. The design methodology for customized fixation system could be used for other fractures in mandible or other bones to acquire better mechanical behavior of the system and improve stable environment for bone healing. And together with SLM, the customized plate with optimal structure could be designed and fabricated rapidly to satisfy the urgent time requirements for treatment.

[Simulation prediction of bone defect repair using biodegradable scaffold based on finite element method].

Aiming at the problem of scaffold degradation in bone tissue engineering, we studied the feasibility that controlls bone defect repair effect with the inhomogeneous structure of scaffold. The prediction model of bone defect repair which contains governing equations for bone formation and scaffold degradation was constructed on the basis of analyzing the process and main influence factors of bone repair in bone tissue engineering. The process of bone defect repair and bone structure after repairing can be predicted by combining the model with finite element method (FEM). Bone defect repair effects with homogenous and inhomogeneous scaffold were simulated respectively by using the above method. The simulation results illustrated that repair effect could be impacted by scaffold structure obviously and it can also be controlled via the inhomogeneous structure of scaffold with some feasibility.

Utility of Six Ultrasound-Based Risk Stratification Systems in the Diagnosis of AUS/FLUS Thyroid Nodules.

RATIONALE AND OBJECTIVES: To estimate the diagnostic performance of the currently used ultrasound (US)-based risk stratification systems (RSSs) (American Thyroid Association, American Association of Clinical Endocrinologists, American College of Endocrinology, and Association Medici Endocrinology Medical Guidelines for Clinical Practice for the Diagnosis and Management of Thyroid Nodules, European Thyroid Association Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules in Adults [EU-TIRADS], American College of Radiology Thyroid Imaging Reporting and Data System [ACR-TIRADS], Chinese Guidelines for Ultrasound Malignancy Risk Stratification of Thyroid Nodules [C-TIRADS], and Thyroid Imaging Reporting and Data System Developed by Kwak et al [Kwak-TIRADS]) for atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) thyroid nodules. MATERIALS AND METHODS: This retrospective study included 514 consecutive AUS/FLUS nodules in 481 patients with final diagnosis. The US characteristics were reviewed and classified using the categories defined by each RSS. The diagnostic performance was evaluated and compared using a generalized estimating equation method. RESULTS: Of the 514 AUS/FLUS nodules, 148 (28.8%) were malignant and 366 (71.2%) were benign. The calculated malignancy rate increased from the low-risk to high-risk categories for all RSSs (all P < .001). Interobserver correlation for both US features and RSSs showed substantial to almost perfect agreement. The diagnostic efficacy of Kwak-TIRADS (AUC=0.808) and C-TIRADS (AUC=0.804) were similar (P = .721) and higher than those of other RSSs (all P < .05). The EU-TIRADS and Kwak-TIRADS exhibited similar sensitivity (86.5% vs 85.1%, P = .739) and were only higher than that of the C-TIRADS (all P < .05). The specificity of C-TIRADS and ACR-TIRADS were similar (78.1% vs 72.1%, P = .06) and were higher than those of other RSSs (all P < .05). CONCLUSION: Currently used RSSs can provide risk stratification for AUS/FLUS nodules. Kwak-TIRADS and C-TIRADS have the highest diagnostic efficacy in identifying malignant AUS/FLUS nodules. A detailed knowledge of the benefits and shortcomings of the various RSSs is essential.

An enzyme-free sensing platform for miRNA detection and in situ imaging in clinical samples based on DNAzyme cleavage-triggered catalytic hairpin assembly.

MicroRNA (miRNA) is demonstrated to be associated with the occurrence and development of various diseases including cancer. Currently, most miRNA detection methods are confined to in vitro detection and cannot obtain information on the temporal and spatial expression of miRNA in relevant tissues and cells. In this work, we established a novel enzyme-free method that can be applied to both in vitro detection and in situ imaging of miRNA by integrating DNAzyme and catalytic hairpin assembly (CHA) circuits. This developed CHA-Amplified DNAzyme miRNA (CHAzymi) detection system can realize the quantitively in vitro detection of miR-146b (the biomarker of papillary thyroid carcinoma, PTC) ranging from 25 fmol to 625 fmol. This strategy has also been successfully applied to in situ imaging of miR-146b both in human PTC cell TPC-1 and clinical samples, showing its capacity as an alternative diagnostic method for PTC. Furthermore, this CHAzymi system can be employed as a versatile sensing platform for various miRNAs by revising the relevant sequences. The results imply that this system may expand the modality of miRNA detection and show promise as a novel diagnostic tool in clinical settings, providing valuable insights for effective treatment and management of the disease.

Comparative analysis of chloroplast genomes of endangered heterostylous species Primula wilsonii and its closely related species.

Primula, well known for its heterostyly, is the largest genus in the family Primulaceae with more than 500 species. The considerable species number has introduced a huge challenge for taxonomy. The phylogenetic relationships among Primula still maintain unresolved due to frequent hybridization and introgression between closely related species. In this study, we sequenced and assembled the complete chloroplast genomes of Primula wilsonii Dunn, which is a PSESP (plant species with extremely small populations), using Illumina sequencing and compared its genomic sequences with those of four related Primula species. The chloroplast genomes of Primula species were similar in the basic structure, gene order, and GC content. The detected 38 SSRs (simple sequence repeats) loci and 17 hypervariable regions had many similarities in P. wilsonii, P. anisodora, P. miyabeana, and P. poissonii, but showed a significant difference compared with those in P. secundiflora. Slight variations were observed among Primula chloroplast genomes, in consideration of the relatively stable patterns of IR (inverted repeats) contraction and expansion. Phylogenetic analysis based on chloroplast genomes and protein-coding genes confirmed three major clades in Chinese Primula, but the infrageneric sections were not in accordance with morphological traits. The P. poissonii complex was confirmed here and P. anisodora was the most closely related species to P. wilsonii. Overall, the chloroplast genome sequences provided useful genetic and evolutionary information for phylogeny and population genetics on Chinese Primula species.

Experimental validation of a new model for mandibular motions.

Long-term excessive forces loading from muscles of mastication during mandibular motions may result in disorders of temporomandibular joint (TMJ), myofascial pain, and restriction of jaw opening and closing. Current analysis of mandibular movements is generally conducted with a single opening, protrusive and lateral movements rather than composite motions that the three can be combined arbitrarily. The objective of this study was to construct theoretical equations reflecting the correlation between composite motions and muscle forces, and consequently to analyze the mandibular composite motions and the tensions of muscles of mastication in multiple dimensions. The muscle performances such as strength, power, and endurance of mandibular motions were analyzed and the effective motion range of each muscle was derived. The mandibular composite motion model was simplified by calculating muscle forces. An orthogonal rotation matrix based on muscle forces was established. A 3D printed mandible was used for in vitro simulation of mandibular motions on a robot and measurements of force were conducted. The theoretical model and forces were verified through a trajectory tracing experiment of mandibular motions driven by a 6-axis robot with force/torque sensors. Through the analysis of the mandibular composite motion model, the motion form was obtained and transferred to guide the motions of the robot. The error between the experimental data obtained by the 6-axis force/torque sensors and the theoretical data was within 0.6 N. Our system provides excellent visualization for analyzing the changes of muscle forces and locations during various mandibular movements. It is useful for clinicians to diagnose and formulate treatment for patients who suffer from (temporomandibular joint disorders) TMDs and restrict jaw movements. The system can potentially offer the comparison before and after treatment of TMDs or jaw surgery.

3D printed PEKK bone analogs with internal porosity and surface modification for mandibular reconstruction: An in vivo rabbit model study.

Polyetheretherketone (PEEK) and its derivative polyetherketoneketone (PEKK) have been used as implant materials for spinal fusing and enjoyed their success for many years because of their mechanical properties similar to bone and their chemical inertness. The osseointegration of PEEKs is datable. Our strategy was to use custom-designed and 3D printed bone analogs with an optimized structure design and a modified PEKK surface to augment bone regeneration for mandibular reconstruction. Those bone analogs had internal porosities and a bioactive titanium oxide surface coating to promote osseointegration between native bone and PEKK analogs. Our workflow was 3D modeling, bone analog designing, structural optimization, mechanical analysis via finite element modeling, 3D printing of bone analogs and subsequently, an in vivo rabbit model study on mandibular reconstruction and histology evaluation. Our results showed the finite element analysis validated that the porous PEKK analogs provided a mechanical-sound structure for functional loadings. The bone analogs offered a perfect replacement for segmented bones in the terms of shape, form and volume for surgical reconstruction. The in vivo results showed that bioactive titanium oxide coating enhanced new bone in-growth into the porous PEKK analogs. We have validated our new approach in surgical mandibular reconstruction and we believe our strategy has a significant potential to improve mechanical and biological outcomes for patients who require mandibular reconstruction procedures.

Gasless submental-transoral combined approach endoscopic thyroidectomy: a new surgical technique.

Background: The development of transoral endoscopic vestibular approach thyroidectomy (TOETVA) has been limited by inherent defects, such as mental nerve injury and carbon dioxide (CO2)-related complications. Herein, we proposed a new technique without CO2 called gasless submental-transoral combined approach endoscopic thyroidectomy (STET) to solve the problems in TOETVA. Methods: We reviewed 75 patients who successfully underwent gasless STET using novel instruments at our institution from November 2020 to November 2021. A main incision of approximately 2 cm was made in the natural submental crease line and then combined with two vestibule incisions to complete the procedure. Demographic data, surgical technique and perioperative outcomes were retrospectively recorded. Results: Thirteen male and sixty-two female patients with a mean age of 34.0 ± 8.1 years were enrolled in this study. Sixty-eight patients had papillary thyroid carcinomas and seven had benign nodules. We successfully performed all gasless STET without conversion to open surgery. The average postoperative hospital stay was 4.2 ± 1.8 days. One transient recurrent laryngeal nerve injury and two transient hypoparathyroidisms were observed. Three patients complained of slight lower lip numbness on the first postoperative day. One case of lymphatic fistula, subcutaneous effusion, and incision swelling occurred each, all of which were conservatively cured. One patient developed a recurrence six months after surgery. Conclusions: Gasless STET using our own designed suspension system is technically safe and feasible with reasonable operative and oncologic results.

Lever arm on bracket vs. lever arm on archwire: A 3D finite element method study of mechanics of miniscrew-supported lingual en-masse retraction of maxillary anterior teeth.

OBJECTIVE: To compare the deformation of the main archwire and 3D movements of maxillary anterior teeth during miniscrew-supported en-masse retraction with the lever arm on the archwire and on the brackets in lingual orthodontic treatment in finite element analysis (FEM) simulation. MATERIAL AND METHODS: A 3D dental-alveolar model with bonded 0.018×0.025-inch slot lingual brackets and a 0.017×0.025-inch dimension stainless-steel archwire was created. Four FEM models were created based on a 3D dental-alveolar model: in Models A and C, the lever arms were attached to the lingual bracket, while in Models B and D, the lever arms were attached to the archwire. Meanwhile, in Models A and B, the miniscrews were placed in between the molars, while in Models C and D, the miniscrews were positioned on the palatal roof. After a 1.5N retraction force was applied from the miniscrew to the end of the lever arm, the initial movements in the sagittal, transversal, and vertical planes were recorded and analysed for maxillary anterior teeth. RESULTS: In Models B and D, smaller deformation of the main archwire and less prominent bowing effect were noticed in both sagittal and vertical directions compared to their counter groups. In Models C and D, the central incisors showed less torque loss in the sagittal direction and more canine intrusion vertically. CONCLUSIONS: For the same lever arm-miniscrew retraction configuration, the lever arm on the bracket showed less deformation of the main archwire and more body movement of the teeth than the lever arm on the archwire group. With the same level arm height, the transverse and vertical bowing effect is reduced when the lever arm was placed distal to the central incisor and the miniscrews placed next to the palatal suture.

Interpeduncular cistern intrathecal targeted drug delivery for intractable postherpetic neuralgia: A case report.

BACKGROUND: Intractable postherpetic neuralgia (PHN) can be difficult to manage even with aggressive multimodal therapies. Patients who experience uncontrolled refractory cranial PHN despite conservative treatment may benefit from an intrathecal drug delivery system (IDDS). For craniofacial neuropathic pain, the traditional approach has been to place the intrathecal catheter tip below the level of the cranial nerve root entry zones, which may lead to insufficient analgesia. CASE SUMMARY: We describe a 69-year-old man with a 1-year history of PHN after developing a vesicular rash in the ophthalmic division of cranial nerve V (trigeminal nerve) distribution. The pain was rated 7-8 at rest and 9-10 at breakthrough pain (BTP) on a numeric rating scale. Despite receiving aggressive multimodal therapies including large doses of oral analgesics (gabapentin 150 mg q12 h, oxycodone 5 mg/acetaminophen 325 mg q6 h, and lidocaine 5% patch 700 mg q12 h) and sphenopalatine ganglion block, there was no relief of pain. Subsequently, the patient elected to have an implantable IDDS with the catheter tip placed at the interpeduncular cistern. The frequency of BTP episodes decreased. The patient's continuous daily dose was adjusted to 0.032 mg/d after 3 mo of follow-up and stopped 5 mo later. He did not report pain or other discomfort at outpatient follow-up 6 mo and 1 year after stopping intracisternal hydromorphone. CONCLUSION: The use of interpeduncular cistern intrathecal infusion with low-dose hydromorphone by IDDS may be effective for severe craniofacial PHN.

A Novel Helper qPCR Assay for the Detection of miRNA Using Target/Helper Template for Primer Formation.

A novel, simple, and sensitive quantitative polymerase chain reaction (qPCR) technology, which is termed as helper qPCR, was established to detect miRNA. In this assay, the target miRNA sequence was introduced as helper template for a reaction switch preforming two-step real-time qPCR strategy. Firstly, the reverse primer was reverse transcribed to form "mediator primer" after binding to the target miRNA. Then, the mediator primer was further extended to form "active template" with annealing to the mediator template. In the end, the active template was amplified and detected by the qPCR reaction system with the help of reverse and forward primers. The SYBR Green dye was used for fluorescence quantification, which is quicker and cheaper than the fluorescent probes, as the detection limit of this assay was 1 pM. This helper qPCR system can be used for different miRNAs detection by redesigning reverse primer for target, indicating this strategy could afford good performance in detecting multiple miRNAs and has a promising application prospect.

Evaluation of a custom-designed human-robot collaboration control system for dental implant robot.

BACKGROUND: The purpose of this study is to develop a methodology to better control a human-robot collaboration for robotic dental implant placement. We have designed a human-robot collaborative implant system (HRCDIS) which is based on a zero-force hand-guiding concept and a operational task management workflow that can achieve highly accurate and stable osteotomy drilling based on a surgeon's decision and robotic arm movements during implant surgery. METHOD: The HRCDIS brings forth the robot arm positions, exact drilling location, direction and performs automatic drilling. The HRCDIS can also avoid complex programing in the robot. The purpose of the study is to evaluate the accuracy of drilling resulting from our developed operational task management method (OTMM). The OTMM can enable the robot to switch, pause, and resume drilling tasks. The force required for hand-guiding in a zero-force control mode of the robot was detected by a 6D force sensor. We compared our force data to those provided by the manufacturer's manual. The study was conducted on a phantom head with a 3D-printed jaw bone to verify the validity of our HRCDIS. We appraised the discrepancies between free-hand drillings and the HRCDIS controlled drillings at apical centre and head centre of the implant and implant angulation to the baseline data from a virtual surgical planning model. RESULTS: The average required force used by hand-guiding to operate the robot with HRCDIS was near 7 Newton which is much less than the manufacturer's specification (30 Newton). The results from our study showed that the average error at implant head was 1.04 ± 0.37 mm, 1.56 ± 0.52 mm at the implant apex, and deviation of implant angle was 3.74 ± 0.67°. CONCLUSIONS: The results from this study validate the merit of the human-robot collaboration control by the HRCDIS. Based on the improved navigation system using HRCDIS, a robotic implant placement can provide seamless drilling with ease, efficiency and accuracy.

Biomechanical behavior of mandible with posterior marginal resection using finite element analysis.

This study aims to characterize biomechanical behavior of various designs of posterior mandibular marginal resection under functional loadings using finite element method. The ultimate goal of this work is to provide clinically relevant information to prevent postoperative fracture and to stipulate prophylactic internal fixation for planning of marginal mandibulectomy. A 3D mandibular master model was reconstructed from cone beam computed tomography images. Different marginal resection models were created based on three design parameters, namely, defect curvilinear radius, anterior-posterior defect width and residual height of the mandibular body. Functional loadings from incisors (60 N) and contralateral first molar area (200 N) were applied to designed models and stress patterns were compared of five groups with curvilinear radius from 0 (conventional rectangular shape), 2.5, 3.5, 5, and 6 mm. Models with 25, 35 and 45 mm defect width mimic defects varied from canine to 3rd molar were tested. Residual height range from 10 to 4 mm was assessed. The results show high stresses predominated in the occlusal area and the posterior inferior border near the resection corner. The average maximum stress decreased by 29.8% (r = 2.5 mm), 51.9% (r = 3.5 mm), 54.4% (r = 5 mm), and 59.3% (r = 6 mm) compared to the baseline of r = 0 mm. The results from the combined defect width/residual height models demonstrate the increase of defect width and the decrease in residual height resulted in the increase of maximum stress. Our data also confirm that the factor of residual height supersedes defect width in terms of prevention of postoperative fracture when considering resection design.