Enhancing Conjugation Effect to Develop Nitrogen-Rich Energetic Materials with Higher Energy and Stability.

This work reports a strategy by enhancing conjugation effect and synthesizes a symmetrical and planar compound, 1,2-bis (4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazol-2-yl)diazene (NL24). The incorporation of azo and 1,2,3-triazole moieties manifests a synergistic effect, amplifying the conjugation effect of the azo bridge and thereby elevating the stability of NL24 (Td: 263 °C, IS: 7 J). Notably, NL24, possessing a structural configuration comprising four tetrazoles harboring a total of 24 nitrogen atoms, exhibits excellent detonation performances (ΔHf: 6.06 kJ g-1, VD: 9002 m s-1). This strategy achieves the balance of energy and stability of polycyclic tetrazoles and provides a direction for high-performance energetic materials.

Research on Inter-Frame Feature Mismatch Removal Method of VSLAM in Dynamic Scenes.

Visual Simultaneous Localization and Mapping (VSLAM) estimates the robot's pose in three-dimensional space by analyzing the depth variations of inter-frame feature points. Inter-frame feature point mismatches can lead to tracking failure, impacting the accuracy of the mobile robot's self-localization and mapping. This paper proposes a method for removing mismatches of image features in dynamic scenes in visual SLAM. First, the Grid-based Motion Statistics (GMS) method was introduced for fast coarse screening of mismatched image features. Second, an Adaptive Error Threshold RANSAC (ATRANSAC) method, determined by the internal matching rate, was proposed to improve the accuracy of removing mismatched image features in dynamic and static scenes. Third, the GMS-ATRANSAC method was tested for removing mismatched image features, and experimental results showed that GMS-ATRANSAC can remove mismatches of image features on moving objects. It achieved an average error reduction of 29.4% and 32.9% compared to RANSAC and GMS-RANSAC, with a corresponding reduction in error variance of 63.9% and 58.0%, respectively. The processing time was reduced by 78.3% and 38%, respectively. Finally, the effectiveness of inter-frame feature mismatch removal in the initialization thread of ORB-SLAM2 and the tracking thread of ORB-SLAM3 was verified for the proposed algorithm.

[Comparison on blood-prostate barrier permeability of tanshinone extract and corresponding major monomers].

In this study, the transmittance of tanshinone Ⅱ_A(Tan Ⅱ_A) and cryptotanshinone(CTS) through the blood-prostate barrier and their distributions in the prostate tissue were compared between tanshinone extract(Tan E) treatment group and the corresponding monomer composition group under the equivalent dose conversion in vitro and in vivo. First, the human prostate epithelial cell line RWPE-1 was cultured in vitro for 21 days for the establishment of a blood-prostate barrier model, and the transmission of Tan Ⅱ_A and CTS through the barrier model was investigated after administration of Tan E and corresponding single active components. Second, SD rats were administrated with 700 mg·kg~(-1) Tan E, 29 mg·kg~(-1) CTS, and 50 mg·kg~(-1) Tan Ⅱ_A by gavage, and plasma and prostate tissue samples were collected at the time points of 2, 4, 8, 12, and 24 h. The Tan Ⅱ_A and CTS concentrations in the samples were determined. The results showed that in the cell model, the cumulative transmission amounts of CTS and Tan Ⅱ_A in the extract at each time point were higher than those of the corresponding single active components(P<0.01). In rats, after the administration of Tan E, the concentrations of Tan Ⅱ_A and CTS in rat plasma and prostate were higher than those of the corresponding single active components. This study demonstrated that the coexisting components in Tan E promoted the penetration of its main pharmacological components Tan Ⅱ_A and CTS through the blood-prostate barrier. The findings provide a theoretical and experimental basis for the application of Tan E in the clinical treatment of prostate-related diseases.

2,2'-Azobis(1,5'-bitetrazole) with a N10 Chain and 1,5'-Bitetrazolate-2N-oxides: Construction of Highly Energetic Nitrogen-Rich Materials Based on C-N-Linked Tetrazoles.

A series of high-nitrogen compounds, including a unique molecule 2,2'-azobis(1,5'-bitetrazole) with a branched N10 chain and 1,5'-bitetrazolate-2N-oxides, were synthesized successfully based on C-N-linked 1,5'-bistetrazoles using azo coupling of N-amine bonds and N-oxide introduction strategies. All compounds were characterized by NMR spectroscopy, IR spectroscopy, elemental analysis, and differential scanning calorimetry, in which the structures of five compounds were further determined by single-crystal X-ray diffraction analysis (2, T-N10B, 3a, 3b, and THX). The nitrogen contents of these five compounds range from 63.62 (THX) to 83.43% (T-N10B), which are much higher than that of CL-20 (38.34%). The heat of formation for the prepared compounds was calculated by using the Gaussian 09 program, with T-N10B having the highest value of 5.13 kJ g-1, about 6 times higher than that of CL-20 (0.83 kJ g-1). The calculated detonation performances by EXPLO5 v6.05.04 show that THX has excellent detonation performance (D = 9581 m s-1, P = 35.93 GPa) and a remarkable specific impulse (Isp = 284.9 s).

A study of auxiliary screening for Alzheimer's disease based on handwriting characteristics.

Background and objectives: Alzheimer's disease (AD) has an insidious onset, the early stages are easily overlooked, and there are no reliable, rapid, and inexpensive ancillary detection methods. This study analyzes the differences in handwriting kinematic characteristics between AD patients and normal elderly people to model handwriting characteristics. The aim is to investigate whether handwriting analysis has a promising future in AD auxiliary screening or even auxiliary diagnosis and to provide a basis for developing a handwriting-based diagnostic tool. Materials and methods: Thirty-four AD patients (15 males, 77.15 ± 1.796 years) and 45 healthy controls (20 males, 74.78 ± 2.193 years) were recruited. Participants performed four writing tasks with digital dot-matrix pens which simultaneously captured their handwriting as they wrote. The writing tasks consisted of two graphics tasks and two textual tasks. The two graphics tasks are connecting fixed dots (task 1) and copying intersecting pentagons (task 2), and the two textual tasks are dictating three words (task 3) and copying a sentence (task 4). The data were analyzed by using Student's t-test and Mann-Whitney U test to obtain statistically significant handwriting characteristics. Moreover, seven classification algorithms, such as eXtreme Gradient Boosting (XGB) and Logistic Regression (LR) were used to build classification models. Finally, the Receiver Operating Characteristic (ROC) curve, accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and Area Under Curve (AUC) were used to assess whether writing scores and kinematics parameters are diagnostic. Results: Kinematic analysis showed statistically significant differences between the AD and controlled groups for most parameters (p < 0.05, p < 0.01). The results found that patients with AD showed slower writing speed, tremendous writing pressure, and poorer writing stability. We built statistically significant features into a classification model, among which the model built by XGB was the most effective with a maximum accuracy of 96.55%. The handwriting characteristics also achieved good diagnostic value in the ROC analysis. Task 2 had a better classification effect than task 1. ROC curve analysis showed that the best threshold value was 0.084, accuracy = 96.30%, sensitivity = 100%, specificity = 93.41%, PPV = 92.21%, NPV = 100%, and AUC = 0.991. Task 4 had a better classification effect than task 3. ROC curve analysis showed that the best threshold value was 0.597, accuracy = 96.55%, sensitivity = 94.20%, specificity = 98.37%, PPV = 97.81%, NPV = 95.63%, and AUC = 0.994. Conclusion: This study's results prove that handwriting characteristic analysis is promising in auxiliary AD screening or AD diagnosis.

Density functional theory studies on N4 and N8 species: Focusing on various structures and excellent energetic properties.

All-nitrogen materials, as a unique branch of energetic materials, have gained huge attentions, of which cyclo-N 5 - derivatives are the representative synthetically reported materials. However, the energetic performance of cyclo-N 5 - compounds has certain limitations and cannot go beyond that of CL-20. In order to reach the higher energy, in this work, we presented two kinds of polynitrogen species, N4 and N8. Two isomers of N4 and four isomers of N8 were fully calculated by using density functional theory (DFT). Theoretical results show that all these polynitrogen materials exhibit excellent heats of formation (7.92-16.60 kJ g-1), desirable detonation performance (D: 9766-11620 m s-1; p: 36.8-61.1 GPa), as well as the remarkable specific impulses (330.1-436.2 s), which are much superior to CL-20. Among them, N 4 -2 (tetraazahedrane) (D: 10037 m s-1; p: 40.1 GPa; Isp: 409.7 s) and cube N 8 -4 (D: 11620 m s-1; p: 61.1 GPa; Isp: 436.2 s) have the highest energetic properties, which are expected to become promising high-energy-density-materials. Moreover, electrostatic surface potentials, Frontier molecular orbitals, infrared spectra, natural bond orbital charges, and weak interactions were also investigated to further understand their relationship between structure and performance.

Dynamic Warning Method for Structural Health Monitoring Data Based on ARIMA: Case Study of Hong Kong-Zhuhai-Macao Bridge Immersed Tunnel.

Structural health monitoring (SHM) is gradually replacing traditional manual detection and is becoming a focus of the research devoted to the operation and maintenance of tunnel structures. However, in the face of massive SHM data, the autonomous early warning method is still required to further reduce the burden of manual analysis. Thus, this study proposed a dynamic warning method for SHM data based on ARIMA and applied it to the concrete strain data of the Hong Kong-Zhuhai-Macao Bridge (HZMB) immersed tunnel. First, wavelet threshold denoising was applied to filter noise from the SHM data. Then, the feasibility and accuracy of establishing an ARIMA model were verified, and it was adopted to predict future time series of SHM data. After that, an anomaly detection scheme was proposed based on the dynamic model and dynamic threshold value, which set the confidence interval of detected anomalies based on the statistical characteristics of the historical series. Finally, a hierarchical warning system was defined to classify anomalies according to their detection threshold and enable hierarchical treatments. The illustrative example of the HZMB immersed tunnel verified that a three-level (5.5 σ, 6.5 σ, and 7.5 σ) dynamic warning schematic can give good results of anomalies detection and greatly improves the efficiency of SHM data management of the tunnel.

Progress in the design and quality control of placeboes for clinical trials of traditional Chinese medicine.

In recent years, new preparations of traditional Chinese medicines (TCMs) have been developed, increasing the need for their clinical trials. Using placeboes rather than control drugs is increasingly popular in clinical trials of TCMs, as the therapeutic effects of the tested TCMs can be more properly judged. The basic attributes of TCM placeboes include similarity, safety, applicability and controllability. In particular, it is necessary to have similarities in appearance, color, smell and taste between the tested TCMs and placeboes. This is quite difficult for some TCMs due to their distinctive smell and taste. On the other hand, according to the TCM theory on homology of medicine and food, many foods also have certain bioactivities, potentially further complicating the selection of materials for TCM placeboes. In this review, firstly, studies on the special smell and taste of TCMs were introduced. Then, the preparation quality evaluation processes for TCM placeboes were summarized and discussed, based on the relevant literature published in recent years and the research results from our own lab. This review will facilitate the further research and development of TCM placeboes.

Exosome circCMTM3 promotes angiogenesis and tumorigenesis of hepatocellular carcinoma through miR-3619-5p/SOX9.

AIM: As one of the most common and lethal carcinomas, hepatocellular carcinoma (HCC) is a global health concern and affects millions of people worldwide. Current treatments for HCC are very limited due to its unclear pathogenesis. Here, we aim to further investigate the role of circCMTM3/microRNA (miR)-3619-5p in HCC. METHODS: Human blood samples were collected from HCC patients and healthy people. Quantitative reverse transcription-polymerase chain reaction and western blot analysis were undertaken to measure levels of circCMTM3, miR-3619-5p, SOX9, and exosome markers. The MTT, colony formation, and Transwell assays were used to examine the viability, migration, and invasion of human umbilical vein endothelial cells (HUVECs), respectively. Tube formation assay was used to assess angiogenesis. Dual luciferase assay was used to validate circCMTM3/miR-3619-5p and miR-3619-5p/SOX9 interactions. A nude mouse xenograft model was used to test the role of circCMTM3 in HCC in vivo. RESULTS: Levels of circCMTM3 in exosomes from HCC patients and cells were elevated. Knockdown of circCMTM3 greatly decreased viability, migration, and invasion of HUVECs, as well as angiogenesis. CircCMTM3 acted as a miR-3619-5p sponge and miR-3619-5p inhibitor reversed the effects of si-circCMTM3 on angiogenesis. MiR-3619-5p directly targeted SOX9 and modulated angiogenesis through SOX9. Furthermore, knockdown of circCMTM3 suppressed angiogenesis and HCC tumor growth in vivo. CONCLUSION: The exosome circCMTM3/miR-3619-5p/SOX9 axis from HCC cells promotes angiogenesis and thus contributes to HCC tumorigenesis.

A new low-profile anatomic locking plate for fixation of comminuted, displaced greater tuberosity fractures of the proximal humerus.

BACKGROUND: Although various implants exist for the fixation of isolated greater tuberosity fractures, few implants are specifically designed for such fractures. The purpose of this study was to investigate the clinical and radiologic outcomes of open reduction-internal fixation with a low-profile anatomic locking plate for comminuted greater tuberosity fractures of the proximal humerus. METHODS: From November 2012 to February 2018, 24 patients with displaced and comminuted isolated greater tuberosity fractures were treated with the new low-profile anatomic locking plate. To determine clinical outcomes, we evaluated active range of motion; the visual analog scale pain score; the Constant-Murley score; the Disabilities of the Arm, Shoulder and Hand score; radiographs; and complications. RESULTS: In all cases, a mean follow-up period of 29.3 months (range, 18-48 months) was completed. All patients achieved bone union with a mean healing time of 11.3 weeks (range, 8-16 weeks). The mean Constant-Murley score was 91.1 points (range, 69-100 points), with a rate of good to excellent results of 95.8%. The average Disabilities of the Arm, Shoulder and Hand score was 9.9 points (range, 2-25 points), and the mean visual analog scale pain score was 1.1 points (range, 0-4 points). Mean active forward flexion, abduction, external rotation, and internal rotation (level) were 157°, 152°, and 40°, and T11, respectively. Postoperatively, 1 patient had persistent shoulder stiffness, and 1 patient had recurrence of shoulder dislocation because of a falling injury during badminton. No serious complications such as subacromial impingement, malunion, nonunion, loss of reduction, or implant failure occurred. CONCLUSIONS: The new low-profile anatomic locking plate was useful for the treatment of comminuted isolated greater tuberosity fractures as it provided reliable stability and satisfactory radiographic and functional results. The described technique is a simple and effective method and provides a new reliable option for the treatment of isolated greater tuberosity fractures.

Blood exosomal micro ribonucleic acid profiling reveals the complexity of hepatocellular carcinoma and identifies potential biomarkers for differential diagnosis.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide, but there is a shortage of effective biomarkers for its diagnosis. AIM: To explore blood exosomal micro ribonucleic acids (miRNAs) as potential biomarkers for HCC diagnosis. RESULTS: The principal component analysis suggested that daily alcohol consumption could alter the blood exosomal miRNA profiles of hepatitis B virus positive non-HCC patients through miR-3168 and miR-223-3p. The miRNA profiles also revealed the tumor stages of HCC patients. High expression of miR-455-5p and miR-30c-5p, which significantly correlated with better overall survival in tumor tissues, could also be detected in blood exosomes. Two pairs of miRNAs (miR-584-5p/miR-106-3p and miR-628-3p/miR-941) showed a 94.1% sensitivity and 68.4% specificity to differentiate HCC patients from non-HCC patients. The specificity of the combination was substantially influenced by alcohol consumption habits. CONCLUSION: This study suggested that blood exosomal miRNAs can be used as new non-invasive diagnostic tools for HCC. However, their accuracy could be affected by tumor stage and alcohol consumption habits.

[Ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures].

OBJECTIVE: To explore clinical effects of ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures. METHODS: From January 2015 to March 2017, 20 patients with acute closed Achilles tendon rupture were treated by minimal traverse-cross technique repair with ultrasound guided. Among them, including 13 males and 7 females, aged from 28 to 49 years old with an average of(31.3 ±4.5) years old. All patients were single side injury. Fifteen patients on the left side and 5 patients were on the right side. The time from injury to operation ranged from 1 to 5 days with an average of (2.5±0.7) days. Operative time, postoperative complications were observed, and AOFAS score before and after operation at 12 months were compared. RESULTS: All patients were followed up for 12 to 27 months with an average of(15.2±4.9) months. Operative time ranged from 33 to 65 min with an average of(43.7±5.6) min. Incision of one patient were continued oozing and improved after changing dressings, other patients were healed at stage I. No sural nerve irritation symptoms and palindromic rapture of heel tendon occurred. AOFAS score was improved from 65.2±7.4 before operation to 97.7±4.7 after operation at 12 months (t=22.5, P<0.01); 18 patients got excellent results and 2 good. CONCLUSIONS: Ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures, which promise minimal incision, protect sural nerve, ensure quality of tendon anastomosis and fixation, and is a ideal method for repairing acute closed Achilles tendon ruptures.

Association of the oral microbiome with the progression of impaired fasting glucose in a Chinese elderly population.

Objective: The oral microbiota is associated with the risk of type 2 diabetes (T2D), but the relationship between the oral microbiota and disease progression in the elderly population remains to be determined. Design: In our study, we recruited 150 elderly Chinese residents and divided them into three groups according to their fasting glucose (FG) level: normal (N), high (H), and very high (VH). Their biochemical indexes were analyzed using blood samples. Saliva samples were collected and the oral microbiome was profiled by high-throughput sequencing of the V3-V4 area of the 16S rRNA gene. Result: Our results revealed that the VH group showed deterioration of the metabolic phenotype and dysbiosis of the oral microbiota simultaneously when compared to the other two groups. Furthermore, potential disease-associated bacterial genera including Leptotrichia, Staphylococcus, Catonella, and Bulleidia were significantly enriched in the VH group. Conclusions: These results suggest that dysbiosis of the oral microbiota may be a typical feature of hyperglycemia and might also contribute to disease aggravation in the progression of hyperglycemias.

Ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures / 中国骨伤

OBJECTIVE@#To explore clinical effects of ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures.@*METHODS@#From January 2015 to March 2017, 20 patients with acute closed Achilles tendon rupture were treated by minimal traverse-cross technique repair with ultrasound guided. Among them, including 13 males and 7 females, aged from 28 to 49 years old with an average of(31.3 ±4.5) years old. All patients were single side injury. Fifteen patients on the left side and 5 patients were on the right side. The time from injury to operation ranged from 1 to 5 days with an average of (2.5±0.7) days. Operative time, postoperative complications were observed, and AOFAS score before and after operation at 12 months were compared.@*RESULTS@#All patients were followed up for 12 to 27 months with an average of(15.2±4.9) months. Operative time ranged from 33 to 65 min with an average of(43.7±5.6) min. Incision of one patient were continued oozing and improved after changing dressings, other patients were healed at stage I. No sural nerve irritation symptoms and palindromic rapture of heel tendon occurred. AOFAS score was improved from 65.2±7.4 before operation to 97.7±4.7 after operation at 12 months (t=22.5, <0.01); 18 patients got excellent results and 2 good.@*CONCLUSIONS@#Ultrasound-guided minimal traverse-cross technique repair for acute closed Achilles tendon ruptures, which promise minimal incision, protect sural nerve, ensure quality of tendon anastomosis and fixation, and is a ideal method for repairing acute closed Achilles tendon ruptures.

Influence of Medial Support Screws on the Maintenance of Fracture Reduction after Locked Plating of Proximal Humerus Fractures.

BACKGROUND: Technical aspects of the correct placement of medial support locking screws in the locking plate for proximal humerus fractures remain incompletely understood. This study was to evaluate the clinical relationship between the number of medial support screws and the maintenance of fracture reduction after locked plating of proximal humerus fractures. METHODS: We retrospectively evaluated 181 patients who had been surgically treated for proximal humeral fractures (PHFs) with a locking plate between September 2007 and June 2013. All cases were then subdivided into one of four groups as follows: 75 patients in the medial cortical support (MCS) group, 26 patients in the medial multiscrew support (MMSS) group, 29 patients in the medial single screw support (MSSS) group, and 51 patients in the no medial support (NMS) group. Clinical and radiographic evaluations included the Constant-Murley score (CM), visual analogue scale (VAS), complications, and revision surgeries. The neck-shaft angle (NSA) was measured in a true anteroposterior radiograph immediately postoperation and at final follow-up. One-way analysis of variance or Kruskal-Wallis test was used for statistical analysis of measurement data, and Chi-square test or Fisher's exact test was used for categorical data. RESULTS: The mean postoperative NSAs were 133.46° ± 6.01°, 132.39° ± 7.77°, 135.17° ± 10.15°, and 132.41° ± 7.16° in the MCS, MMSS, MSSS, and NMS groups, respectively, and no significant differences were found (F = 1.02, P = 0.387). In the final follow-up, the NSAs were 132.79° ± 6.02°, 130.19° ± 9.25°, 131.28° ± 12.85°, and 127.35° ± 8.50° in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 4.40, P = 0.008). There were marked differences in the NSA at the final follow-up between the MCS and NMS groups (P = 0.004). The median (interquartile range [IQR]) NSA losses were 0.0° (0.0-1.0)°, 1.3° (0.0-3.1)°, 1.5° (1.0-5.2)°, and 4.0° (1.2-7.1)° in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 60.66, P < 0.001). There were marked differences in NSA loss between the MCS and the other three groups (MCS vs. MMSS, Z = 3.16, P = 0.002; MCS vs. MSSS, Z = 4.78, P < 0.001; and MCS vs. NMS, Z = 7.34, P < 0.001). There was also significantly less NSA loss observed in the MMSS group compared to the NMS group (Z = -3.16, P = 0.002). However, there were no significant differences between the MMSS and MSSS groups (Z = -1.65, P = 0.225) or the MSSS and NMS groups (Z = -1.21, P = 0.099). The average CM scores were 81.35 ± 9.79, 78.04 ± 8.97, 72.76 ± 10.98, and 67.33 ± 12.31 points in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 18.68, P < 0.001). The rates of excellent and good CM scores were 86.67%, 80.77%, 65.52%, and 43.14% in the MCS, MMSS, MSSS, and NMS groups, respectively (χ2 = 29.25, P < 0.001). The median (IQR) VAS scores were 1 (0-2), 1 (0-2), 2 (1-3), and 3 (1-5) points in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 27.80, P < 0.001). Functional recovery was markedly better and VAS values were lower in the MCS and MMSS groups (for CM scores: MCS vs. MSSS, P < 0.001; MCS vs. NMS, P < 0.001; MMSS vs. MSSS, P = 0.031; and MMSS vs. NMS, P < 0.001 and for VAS values: MCS vs. MSSS, Z = 3.31, P = 0.001; MCS vs. NMS, Z = 4.64, P < 0.001; MMSS vs. MSSS, Z = -2.09, P = 0.037; and MMSS vs. NMS, Z = -3.16, P = 0.003). CONCLUSIONS: Medial support screws might help enhance mechanical stability and maintain fracture reduction when used to treat PHFs with medial metaphyseal comminution or malreduction.

Influence of Medial Support Screws on the Maintenance of Fracture Reduction after Locked Plating of Proximal Humerus Fractures / 中华医学杂志(英文版)

Background@#Technical aspects of the correct placement of medial support locking screws in the locking plate for proximal humerus fractures remain incompletely understood. This study was to evaluate the clinical relationship between the number of medial support screws and the maintenance of fracture reduction after locked plating of proximal humerus fractures.@*Methods@#We retrospectively evaluated 181 patients who had been surgically treated for proximal humeral fractures (PHFs) with a locking plate between September 2007 and June 2013. All cases were then subdivided into one of four groups as follows: 75 patients in the medial cortical support (MCS) group, 26 patients in the medial multiscrew support (MMSS) group, 29 patients in the medial single screw support (MSSS) group, and 51 patients in the no medial support (NMS) group. Clinical and radiographic evaluations included the Constant-Murley score (CM), visual analogue scale (VAS), complications, and revision surgeries. The neck-shaft angle (NSA) was measured in a true anteroposterior radiograph immediately postoperation and at final follow-up. One-way analysis of variance or Kruskal-Wallis test was used for statistical analysis of measurement data, and Chi-square test or Fisher's exact test was used for categorical data.@*Results@#The mean postoperative NSAs were 133.46° ± 6.01°, 132.39° ± 7.77°, 135.17° ± 10.15°, and 132.41° ± 7.16° in the MCS, MMSS, MSSS, and NMS groups, respectively, and no significant differences were found (F = 1.02, P = 0.387). In the final follow-up, the NSAs were 132.79° ± 6.02°, 130.19° ± 9.25°, 131.28° ± 12.85°, and 127.35° ± 8.50° in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 4.40, P = 0.008). There were marked differences in the NSA at the final follow-up between the MCS and NMS groups (P = 0.004). The median (interquartile range [IQR]) NSA losses were 0.0° (0.0-1.0)°, 1.3° (0.0-3.1)°, 1.5° (1.0-5.2)°, and 4.0° (1.2-7.1)° in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 60.66, P < 0.001). There were marked differences in NSA loss between the MCS and the other three groups (MCS vs. MMSS, Z = 3.16, P = 0.002; MCS vs. MSSS, Z = 4.78, P < 0.001; and MCS vs. NMS, Z = 7.34, P < 0.001). There was also significantly less NSA loss observed in the MMSS group compared to the NMS group (Z = -3.16, P = 0.002). However, there were no significant differences between the MMSS and MSSS groups (Z = -1.65, P = 0.225) or the MSSS and NMS groups (Z = -1.21, P = 0.099). The average CM scores were 81.35 ± 9.79, 78.04 ± 8.97, 72.76 ± 10.98, and 67.33 ± 12.31 points in the MCS, MMSS, MSSS, and NMS groups, respectively (F = 18.68, P < 0.001). The rates of excellent and good CM scores were 86.67%, 80.77%, 65.52%, and 43.14% in the MCS, MMSS, MSSS, and NMS groups, respectively (χ = 29.25, P < 0.001). The median (IQR) VAS scores were 1 (0-2), 1 (0-2), 2 (1-3), and 3 (1-5) points in the MCS, MMSS, MSSS, and NMS groups, respectively (H = 27.80, P < 0.001). Functional recovery was markedly better and VAS values were lower in the MCS and MMSS groups (for CM scores: MCS vs. MSSS, P < 0.001; MCS vs. NMS, P < 0.001; MMSS vs. MSSS, P = 0.031; and MMSS vs. NMS, P < 0.001 and for VAS values: MCS vs. MSSS, Z = 3.31, P = 0.001; MCS vs. NMS, Z = 4.64, P < 0.001; MMSS vs. MSSS, Z = -2.09, P = 0.037; and MMSS vs. NMS, Z = -3.16, P = 0.003).@*Conclusions@#Medial support screws might help enhance mechanical stability and maintain fracture reduction when used to treat PHFs with medial metaphyseal comminution or malreduction.

Design and biomechanical study of a novel double-leaf proximal humeral locking plate / 医用生物力学

Objective To design a novel double-leaf proximal humeral locking plate for fixing greater and lesser tuberosities in complex proximal humeral fractures, and evaluate its fixing stability by biomechanical tests. Methods Twelve fresh-frozen humerus specimens with intact rotator cuff were randomly divided into two groups (Group A and Group B) to establish the same greater and lesser tuberosities fracture models. Specimens in Group A were fixed with the double-leaf proximal humeral locking plate, while specimens in Group B were fixed with the proximal humeral internal locking system (PHILOS) and tension band suture, and a 3.5-mm cannulated screw was added to stabilize the lesser tuberosity. The tensile test on subscapularis, infraspinatus and teres, supraspinatus as well as the load-to-failure test on greater and lesser tuberosities were performed on specimens in two groups. Results For subscapularis tensile tests, displacements under 150 N tensile stretch and after fatigue test in Group A were both significantly smaller than those in Group B (P0.05). For supraspinatus tensile tests, there were no statistical differences between Group A and B in displacements under 90 N tensile stretch and after fatigue test (P>0.05). For load-to-failure tests on lesser tuberosity, the failure load in Group A was significantly greater than that in Group B (P0.05). Conclusions Compared with the ordinary tension band suture plus cannulated screw for fixing lesser tuberosity, the novel double-leaf proximal humeral locking plate shows more obvious biomechanical stability, with the advantage of simultaneously fixing greater and lesser tuberosities. The research findings provide a new choice for the clinical treatment of complex proximal humeral fractures.

Design and biomechanical study of a novel double-leaf proximal humeral locking plate / 医用生物力学

Objective To design a novel double-leaf proximal humeral locking plate for fixing greater and lesser tuberosities in complex proximal humeral fractures,and evaluate its fixing stability by biomechanical tests.Methods Twelve fresh-frozen humerus specimens with intact rotator cuff were randomly divided into two groups (Group A and Group B) to establish the same greater and lesser tuberosities fracture models.Specimens in Group A were fixed with the double-leaf proximal humeral locking plate,while specimens in Group B were fixed with the proximal humeral internal locking system (PHILOS) and tension band suture,and a 3.5-mm cannulated screw was added to stabilize the lesser tuberosity.The tensile test on subscapularis,infraspinatus and teres,supraspi natus as well as the load-to-failure test on greater and lesser tuberosities were performed on specimens in two groups.Results For subscapularis tensile tests,displacements under 150 N tensile stretch and after fatigue test in Group A were both significantly smaller than those in Group B (P ＜ 0.05).For infraspinatus and teres tensile tests,there were no statistical differences between Group A and B in displacements under 150 N tensile stretch and after fatigue test (P ＞ 0.05).For supraspinatus tensile tests,there were no statistical differences between Group A and B in displacements under 90 N tensile stretch and after fatigue test (P ＞ 0.05).For load-to-failure tests on lesser tuberosity,the failure load in Group A was significantly greater than that in Group B (P ＜ 0.05),and the failure displacement in Group A was significantly smaller than that in Group B (P ＜ 0.05).For load-to-failure tests on greater tuberosity,there were no statistical differences between Group A and B in both the failure load and failure displacement (P ＞ 0.05).Conclusions Compared with the ordinary tension band suture plus cannulated screw for fixing lesser tuberosity,the novel double-leaf proximal humeral locking plate shows more obvious biomechanical stability,with the advantage of simultaneously fixing greater and lesser tuberosities.The research findings provide a new choice for the clinical treatment of complex proximal humeral fractures.

Biomechanical advantages of medial support screws in locking plate for treating proximal humerus fractures / 医用生物力学

Objective To evaluate the biomechanical advantages of medial support screws (MSSs) in locking proximal humeral plate for treating proximal humerus fractures. Methods Thirty synthetic left humeri were randomly divided into 3 groups to establish the fracture models. Group A was fixed with a locking proximal humerus plate with medial cortical support, but without MSSs; group B was fixed with 3 MSSs, but without medial cortical support; group C was fixed with neither medial cortical support nor MSSs. Axial compression, torsion, shear stiffness and failure tests were applied on the specimens of the three groups. Results For axial compression tests, the maximum load of group A, B, C was (240.88±19.13), (169.04±19.26), (128.58±17.53) N, respectively; the axial stiffness of group A, B, C was (424.4±101.2), (230.7±40.54), (147.0±29.2) N/mm, respectively, showing significant differences (P0.05). For shear stiffness tests, the maximum load of group A, B, C was (444.71±20.87), (228.79±28.95), (188.73±26.15) N, respectively; the shear stiffness of group A, B, C was (70.0± 54.4), (183.89±29.64), (140.2±32.1) N/mm, respectively, showing significant differences (P0.05). Conclusions Using three MSSs in locking plate for proximal humerus fractures shows optimal biomechanical properties, as compared to the situation without restoration of the medial column support. The reconstruction of the medial cortical support or MSSs for proximal humerus fractures helps to enhance the mechanical stability of the humeral head and prevent failure after internal fixation.

Finite element analysis on titanium elastic nail and reconstruction plate fixation for midshaft clavicular fractures / 医用生物力学

Objective To analyze the stress distribution and peak stress on midshaft clavicular fractures fixed by titanium elastic nail (TEN) or reconstruction plate, respectively. Methods CT data of the clavicle was adopted to reconstruct the intact clavicle model and the midshaft clavicular fracture models with the TEN and reconstruction plate fixation by using Mimics software. All the three dimensional finite element models were analyzed using Abaqus 6.9 software. The distal displacement, the peak stress and stress distribution on the distal clavicle under the axial load (250 N) and vertical load (250 N) were calculated for the three models. Results The axial displacement of the distal clavicle under the axial load showed TEN (0.23 mm)>intact clavicle (0.14 mm)>reconstruction plate (0.11 mm), respectively. While the vertical displacement of the distal clavicle under the vertical load was 5.12 mm for TEN, 3.71 mm for intact clavicle and 2.25 mm for reconstruction plate, respectively. But the peak stress of the clavicle under the axial load was 33.1 MPa for TEN, 18.7 MPa for reconstruction plate, and 15.5 MPa for intact clavicle model, respectively. And the peak stress under the vertical load was 146.3, 64.1, 56.1 MPa in the TEN, intact clavicle model, and reconstruction plate model, respectively. The stress distribution in TEN model under both kinds of loads was similar to that in intact clavicle model, while under the vertical load, the stress distribution in reconstruction plate model was clearly different with that in intact clavicle model. For the implants under the axial load, the peak stresses were 191.5, 52.3 MPa in the TEN model and reconstruction plate model, respectively, and the peak stress on implants under the vertical load was 1 248.0, 421.7 MPa in the TEN model and reconstruction plate model, respectively. Conclusions The TEN for treating midshaft clavicular fractures showed a stress distribution similar to the intact clavicle, with a higher peak stress and a higher peak implant stress at the fracture site. The reconstruction plate fixation for midshaft clavicular fractures was shown to be more stable, but with obvious stress shielding. Therefore, TEN is generally preferable for treating the simple displaced fractures of midshaft clavicle. However, the ipsilateral shoulder should avoid excessive exercise and weight bearing in the early postoperative period.