An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction.

BACKGROUND: During the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches. METHODS: A total of 63 knees' 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study. RESULTS: In AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach. CONCLUSION: Marking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

Mercury pollution risks of agricultural soils and crops in mercury mining areas in Guizhou Province, China: effects of large mercury slag piles.

The historical large mercury slag piles still contain high concentrations of mercury and their impact on the surrounding environment has rarely been reported. In this study, three different agricultural areas [the area with untreated piles (PUT), the area with treated piles (PT), and the background area with no piles (NP)] were selected to investigate mercury slag piles pollution in the Tongren mercury mining area. The mercury concentrations of agricultural soils ranged from 0.42 to 155.00 mg/kg, determined by atomic fluorescence spectrometry of 146 soil samples; and mercury concentrations in local crops (rice, maize, pepper, eggplant, tomato and bean) all exceeded the Chinese food safety limits. Soil and crop pollution trends in the three areas were consistent as PUT > PT > NP, indicating that mercury slag piles have exacerbated pollution. Mercury in the slag piles was adsorbed by multiple pathways of transport into soils with high organic matter, which made the ecological risk of agricultural soils appear extremely high. The total hazard quotients for residents from ingesting mercury in these crops were unacceptable in all areas, and children were more likely to be harmed than adults. Compared to the PT area, treatment of slag piles in the PUT area may decrease mercury concentrations in paddy fields and dry fields by 46.02% and 70.36%; further decreasing health risks for adults and children by 47.06% and 79.90%. This study provided a scientific basis for the necessity of treating large slag piles in mercury mining areas.

Incorporating soil mercury species and fractions into multi-objective risk assessment of a residue disposal site in China.

Environmental problems in soil and water caused by solid waste dumps have become a growing concern. This study proposes an integrated risk assessment model aimed at multi-objectives including human, ecology and groundwater and develops remediation target values at different tiers associated with soil mercury species and fractions in a typical residue disposal site of China. The results show that the residue disposal site was severely contaminated with mercury, with the maximum mercury content in the soil reaching 579.14 mg/kg. The average concentration of vapour mercury, bioaccessible mercury, bioavailable mercury and leachable mercury tested in laboratory was 87.65 mg/kg, 3.15 mg/kg (intestinal phase), 1.654 mg/kg and 0.045 mg/L, respectively. The hazard index calculated using total mercury, bioaccessible mercury and vapour mercury was 7.43 E + 01, 4.42 E + 01, and the remediation target values were7.79 mg/kg and 13.1 mg/kg, respectively. The ecological risk for total mercury and bioavailable mercury was calculated using measured site soil mercury background values of 6390.92 and 94.52, and the remediation target was 0.7 mg/kg and 47.33 mg/kg, respectively. Under Class IV water conditions, the measured and three-phase equilibrium model simulations of leachable mercury resulted in remediation targets of 6 mg/kg and 10 mg/kg for soil mercury. Compared to total mercury, the remediation target values calculated using mercury species and fractions were significantly larger under human health protection, ecology protection and groundwater protection. This results in a reduction in the area of soil to be remediated by 20.3-85.7%, resulting in significant savings in remediation costs. It was concluded that when conducting risk assessment and reuse of mercury-contaminated sites, it is important to consider the species and fractions of mercury in the soil in order to reasonably determine the remediation criteria and scale of remediation to avoid over-remediation and incomplete remediation. At the same time, a comprehensive protection target remediation mechanism should be established by combining different receptors.

Association of the lateral wall integrity with clinical outcomes in older patients with intertrochanteric hip fractures treated with the proximal femoral nail anti-rotation-Asia.

PURPOSE: The purpose of this study is to assess the role of the lateral wall in post-operative clinical outcomes in patients with intertrochanteric fractures treated with the proximal femoral nail anti-rotation-Asia (PFNA-II). METHODS: A cohort of 466 patients (OTA type 31A1 or A2) was divided into two groups: one was intact lateral wall group, and the other was fractured lateral wall group. Radiographic outcomes were measured by using the loss of neck-shaft angle (NSA), femoral neck shortening (FNS), and offset shortening (OS). Functional outcomes were assessed by using the Harris score and SF-36 Physical Component Summary (SF-36 PCS). Post-operative complications were recorded. RESULTS: The fractured lateral wall group had a greater loss of NSA (mean [SD], fractured group (8.7°) [2.7°] vs intact group (4.8°) [2.8°]; mean difference, 3.3° [95% CI 2.9 to 3.8]; P < 0.001) compared with the intact lateral wall group. Similar results were found for FNS and OS. The fractured lateral wall group had a worse Harris scores at the three month follow-up (mean [SD] score, fractured group (66.6) [5.2] points vs intact group (71.3) [5.8] points; mean difference, - 3.3 points [95% CI - 3.9 to - 2.7]; P < 0.001) compared with the intact lateral wall group. Similar results were observed for Harris scores at the three and 12-month follow-ups and SF-36 PCS at the three, six and 12-month follow-ups. The fractured lateral wall group had a higher risk of post-operative complications compared with the intact lateral wall group. CONCLUSION: Among older patients with intertrochanteric fractures, the fractured lateral wall was associated with worse clinical outcomes compared with the intact lateral wall. Clinicians should pay attention to the lateral wall integrity in patients with intertrochanteric fractures treated with the PFNA-II.

Computer-assisted preoperative planning improves the learning curve of PFNA-II in the treatment of intertrochanteric femoral fractures.

BACKGROUND: Intertrochanteric femoral fractures are prevalent among the elderly, and usually demands surgical treatments. Proximal femoral nail antirotation Asian version (PFNA-II) is widely used for intertrochanteric fracture treatment. The computer-assisted preoperative planning (CAPP) system has the potential to reduce the difficulty of PFNA-II in the treatment of intertrochanteric fractures. The aim of the study was to investigate and compare the learning curves of PFNA-II treatment with CAPP and conventional preoperational planning methods for intertrochanteric femoral fractures. METHODS: A total of 125 patients with intertrochanteric fracture who were treated with PFNA-II between March 2012 and June 2015 were retrospectively analyzed. Patients who underwent surgery with CAPP procedure by a junior surgeon were regarded as group A (n = 53); patients who underwent the conventional surgery by another junior surgeon were regarded as group B (n = 72). Each group was divided into three subgroups (case 1-20, case 21-40, case 41-53 or case 41-72). RESULTS: The average operation time of group A was 45.00(42.00, 50.00) minutes, and in group B was 55.00 (50.00, 60.00) minutes (P < 0.01). Average radiation frequency and blood loss were 13.02 ± 2.32, 160.00 (140.00, 170.00) ml and 20.92 ± 3.27, 250.00 (195.00, 279.50) ml, respectively, with significant differences (P < 0.01). The learning curve of the surgical procedure in group A was steeper than that in group B. There were no significant differences in patient reported outcomes, hospital stay and complication rate between the two groups. Significant differences were observed between group A and B in Harris score at last follow-up in the AO/OTA type 31-A2 intertrochanteric fracture (P < 0.05). CONCLUSION: Compared with conventional preoperative planning methods, CAPP system significantly reduced operation time, radiation frequency and blood loss, thus reshaped the learning curve of PFNA-II treatment with lower learning difficulty. TRIAL REGISTRATION: researchregistry4770. Registered 25 March 2019.

The accuracy of intra-operative fluoroscopy in evaluating the reduction quality of intertrochanteric hip fractures.

PURPOSE: To investigate the capability of intra-operative fluoroscopy to determine the reduction quality of intertrochanteric fractures and to determine which view (anteroposterior [AP] or lateral) can better predict the reduction quality. METHODS: A retrospective analysis of 128 patients with intertrochanteric fractures. Two observers were asked to independently evaluate the quality of reduction (positive or non-positive support) based on intra-operative fluoroscopy (AP and lateral view). Results based on CT scans were considered as the gold standard. Sensitivity, specificity, percentage of correct interpretations, and agreement were calculated. RESULTS: At the first reading, sensitivity, false-negative rate, specificity, false-positive rate, and percentage of correct interpretations were 86.1%, 13.9%, 69.4%, 30.6%, and 79.7% for junior resident and 81.0%, 19.0%, 67.3%, 32.7%, and 75.8% for senior resident (all p > 0.05). It was highly predictive of a reliable cortical support when cortical position in AP view was consistent with that in lateral view (85/85, 100% for junior, and 86/86, 100% for senior). Lateral view was generally predictive of a final cortical support when the position between AP and lateral view was inconsistent (90.7% [39/43] vs 9.3% [4/43] for junior, p < 0.001; 92.9% [39/42] vs 7.1% [3/42] for senior). Comparable results were reported at the second reading. The average inter-observer and intra-observer agreement was 0.670 and 0.654, respectively. CONCLUSIONS: We should ensure the cortical support for both AP and lateral view are positive intra-operatively as far as possible. Even if this is not possible, we need to make sure the lateral position is positive support.

Computer-assisted virtual surgical technology in pre-operative design for the reconstruction of calcaneal fracture malunion.

PURPOSE: No computer-assisted pre-operative design for calcaneal fracture malunions has been presented. The aim of the study is to evaluate the intra-operative realization of computer-assisted pre-operative planning (CAPP) and the clinical outcomes based on computer-assisted virtual surgical technology for calcaneal malunions. METHODS: Between 2010 and 2016, 20 patients with 21 calcaneal fracture malunions were retrospectively reviewed with the average follow-up time of 22.3 months (range, 12 to 43 months), which were operatively treated with the help of CAPP. The CAPP steps included the image segmentation, exostectomy of lateral wall, simulated reconstruction of calcaneal thalamus, morphological evaluation, and the implantation of internal fixation devices. Post-operative outcomes were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, SF-36 physical component summary (PCS), VAS for pain, range of motion of ankle, and the morphological parameters of the calcaneus including the axial length of the calcaneus, the height of the posterior facet, the talocalcaneal angle, Böhler's angle, and Gissane's angle. RESULTS: The mean time required for CAPP was 41.8 minutes. All the surgical processes were carried out according to CAPP. Six patients (6 feet) were treated with the joint-preserving osteotomy. Fourteen patients (15 feet) underwent the subtalar distraction bone block arthrodesis, among which the medial displacement calcaneal osteotomy was additionally performed in six patients (6 feet). At the final follow-up, the average AOFAS, SF-36 PCS, and VAS scores were significantly improved to 77.4, 64.3, and 1.4, respectively (P < 0.001). The postoperative calcaneal morphological parameters and the range of motion of ankle were significantly restored (P < 0.05). CONCLUSION: CAPP can assist surgeons in understanding calcaneal malunions, thereby improving intraoperative correction and reconstruction. The satisfying clinical and radiographic outcomes could be provided after treating calcaneal malunions aided by the computer-assisted virtual surgical technology.

Assessment of Screw Length of Proximal Humerus Internal Locking System (PHILOS) Plate for Proximal Humeral Fractures Using Three-Dimensional Computed Tomography Scan.

BACKGROUND Screw perforation and varus collapse are common complications of treatment with a PHILOS (proximal humerus internal locking system) plate for proximal humerus fractures, which are associated with improper screw length selection and lack of medial column support. The purposes of this study were: (1) to measure the proper length of periarticular screws of the PHILOS plate in the humeral head, and (2) to determine what factors influence the screw length and implantation of the inferomedial support screw. MATERIAL AND METHODS Computed tomography (CT) images of the normal proximal humerus in 134 cases were retrospectively reviewed. The length of periarticular screws was measured using three-dimensional (3D) techniques. Intraobserver and interobserver reliability of measurement were evaluated using intraclass correlation coefficients (ICCs). Sex and body height influences on screw length and implantation of the inferomedial screw were analyzed. RESULTS All measurements had excellent agreement (ICC>0.75). The screw length and implantation rate of the inferomedial screw were greater in males than in females. Positive correlations were observed between body height and screw length and implantation of the inferomedial screw (all P<0.001). CONCLUSIONS The screws were longer and the implantation rate was higher for inferomedial screws in males than in females, and were positively correlated with body height. Our data can be used as a reference for surgeons to reduce the number of times screws are changed intraoperatively and to reduce operation duration and minimize use of intraoperative fluoroscopy for proximal humerus fractures treated with the PHILOS plate.

Morphometry of the Tibial Plateau at the Surface and Resected Levels.

BACKGROUND: We aim to make an anthropometric analysis of tibial plateau at the surface level and the resected level and analyze the correlation in lengths between 2 levels. We hypothesized that lengths at the surface level were longer than those at the resected level, which brought soft tissue tolerance for tibial component to overhang. METHODS: Anthropometric data were measured using three-dimensional structures reconstructed from tibial plateaus of 100 knees in 100 Chinese subjects (50 men and 50 women). Mediolateral, medial anteroposterior, and lateral anteroposterior lengths at the surface level and the resected level were measured, and the Pearson's correlation coefficients of these data were calculated. RESULTS: Mediolateral and medial anteroposterior lengths at the surface level were longer than those at the resected level by a mean 2.38 ± 1.29 and 1.99 ± 1.76 mm, respectively. Lateral anteroposterior length at the surface level was shorter than that at the resected level by a mean 1.54 ± 2.49 mm. All these differences between 2 levels had no gender difference. CONCLUSION: Our findings suggest that tibial overhang could be better tolerated in the medial compared to the lateral compartment but this hypothesis has to be further investigated in a clinical study.

Post-operative radiological predictors of satisfying outcomes occurring after intra-articular calcaneal fractures: a three dimensional CT quantitative evaluation.

PURPOSE: No functional outcome related to 3-D CT evaluations for calcaneal fractures has been presented. The aims of this study are to analyze the post-operative morphological parameters of calcaneal fractures in 3-D space and to correlate the 3-D morphological parameters with functional outcomes. METHODS: Between 2009 and 2015, 156 patients operatively treated for displaced calcaneal fractures were retrospectively reviewed with an average follow-up time of 32.4 months. Böhler's angle, Gissane's angle, the length of calcaneal axis, the height of posterior facet, the length of posterior facet, and the subtalar joint congruity were evaluated post-operatively in accordance with 3-D CT. Each parameter was quantified, and then its association with the clinical outcomes assessed by the AOFAS score and Short Form-36 questionnaire was evaluated. RESULTS: The restoration of the length of calcaneal axis, the height of posterior facet, and the length of posterior facet had no significant correlation with the clinical outcomes (P > 0.05). The restoration of Böhler's angle and Gissane's angle had significant correlation with the better AOFAS score (P < 0.001), while no correlation was found with the SF-36 physical component summary score (P > 0.05). No significant association emerged between the clinical outcomes and reconstruction of the posterior facet congruity (P > 0.05). CONCLUSION: The predictable functional outcome is related to the reconstruction of post-operative morphological characteristics of the calcaneus as evaluated on 3-D CT, especially the Böhler's angle and Gissane's angle. Despite post-operative step-off of the posterior facet exiting, the clinical outcomes appear to be not related to the posterior facet congruity.

A quantitative transcriptomic analysis of the physiological significance of mTOR signaling in goat fetal fibroblasts.

BACKGROUND: Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that is a central regulator of cell growth and metabolism. CCI-779 is a specific inhibitor of the mTORC1 signaling pathway. RESULTS: We performed comparative transcriptome profiling on Inner Mongolia Cashmere goat fetal fibroblasts (GFbs) that were treated with CCI-779 and untreated cells. A total of 365 differentially expressed genes (DEGs) appeared between untreated and CCI-779-treated GFbs, with an FDR ≤0.001 and fold-change ≥2. These 365 DEGs were associated with mTOR signaling; 144 were upregulated in CCI-779-treated cells, and 221 were downregulated. Additionally, 300 genes were annotated with 43 Gene Ontology (GO) terms, and 293 genes were annotated with 194 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Three RNA polymerase II and polymerase III subunits, 3 transcription factors, and 5 kinases in mTOR signaling were differentially expressed in CCI-779-treated GFbs. Further 6 DEGs were related to amino acid metabolism, 11 mediated lipid metabolism, 11 participated in carbohydrate metabolism, and 5 were involved in single-nucleotide metabolism. Based on our quantitative transcriptomic analysis, 40 significant DEGs with important function related to metabolism, RNA polymerase, transcription factors and mTOR signaling were selected for qPCR analysis, and the quantitative results between the two analysis methods were concordant. The qPCR data confirmed the differential expression in the RNA-Seq experiments. To validate the translational significance of the findings in certain differentially expressed genes, S6K1 and VEGF were detected by western blot, and these two proteins showed a differential expression between non-treated and treated with CCI-779 groups, which were consistent with mRNA abundance. The data showed a preliminary significance of the findings in the protein levels. CONCLUSIONS: CCI-779 induces transcriptomic changes, and mTOR signaling might have significant function in the activation of RNA polymerase and certain transcription factors and in the metabolism of amino acids, lipids, carbohydrates, and single nucleotides in GFbs. These data filled the vacancy in the systematical profiling of mTOR signaling on Cashmere goat fetal fibroblasts.

mTORC1 mediates peptidoglycan induced inflammatory cytokines expression and NF-κB activation in macrophages.

Peptidoglycan (PGN) is the major structural component of the bacterial cell wall, especially gram positive bacteria, which induces inflammatory responses. Mammalian target of rapamycin (mTOR) regulates the production of inflammatory cytokines induced by antigens, while the function of mTORC1 in peptidoglycan induced inflammatory response is unknown. This study aims to examine the role and the regulatory mechanism of mTOR signaling pathway in peptidoglycan induced cytokine expression in mouse macrophages. We observed that peptidoglycan upregulated the secretion of proinflammatory cytokines IL-6, TNF-α and anti-inflammatory cytokine IL-10 in a dose- and time-dependent manner. mTORC1 positively regulates IL-6 and TNF-α, but negatively regulates IL-10 secretion. mTORC1 regulates NF-κB p65 activation by degrading IκB-α in response to peptidoglycan. mTOR, NF-κB and STAT3 signaling pathways are involved in peptidoglycan induced inflammatory cytokines expression via a TLR1/TLR2-dependent mechanism in macrophages. Thus, mTORC1 pathway regulates the innate immune response to bacterial peptidoglycan.

Pioglitazone Antagonized the Effects of Advanced Glycation End Products on Achilles Tendon Healing and Improved the Recovery of Tendon Biomechanical Properties.

Purpose: Advanced glycation end products (AGEs) often accumulate in the Achilles tendon during the course of diabetes. This study aims to determine the impact of AGEs on tendon repair and explore the role of pioglitazone in mitigating this impact. Methods: Forty-eight male 8 week-old Sprague Dawley rats were selected in this study. After transection of Achilles tendon, the rats were randomly divided into four groups. The Achilles tendons of rats were injected with 1000 mmol/L D-ribose to elevate the content of AGEs within the tendons in two groups, the remaining two groups received injections of phosphate buffered saline (PBS) solution. Subsequently, the first two groups were respectively received oral administration of pioglitazone (20 mg/kg/day) and PBS. The remaining two groups were given the same treatment. The expression of the collagen-I, TNF-α, IL-6 of the repaired tendon were detected. The macroscopic, pathologic and biomechanical aspects of tendon healing were also evaluated. Results: AGEs accumulation in tendon during the healing process increases the expression of inflammatory factors such as TNF-α and IL-6, leading to insufficient synthesis of collagen-I and delayed recovery of the tendon's tensile strength. Pioglitazone significantly attenuated the damage caused by AGEs to the tendon healing process, effectively improving the recovery of tendon tensile strength. Pioglitazone could not inhibit the generation of AGEs in the tissue and also had no impact on the normal healing process of the tendon. Conclusions: Pioglitazone could prevent the deleterious impact of AGEs on the Achilles tendon healing and improve the biomechanical properties of the tendon.

Utilization of Water-Insoluble Carbon Nitride-Phosphotungstic Acid Hybrids in Composite Proton Exchange Membranes.

Phosphotungstic acid (HPW) can retain water in proton exchange membranes to increase proton conductivity; however, its water-soluble nature limits further application. In this work, we combined HPW and graphitic carbon nitride (g-C3N4) via sintering to prepare water-insoluble hybrids (HWN), where HPW was chemically linked to g-C3N4 to fix HPW. Then, HWN fillers were added to a sulfonated polyether ether ketone (SPEEK) matrix to prepare composite membranes. The conductivity of the composite membrane with 10 wt% HWN is up to 0.066 S cm-1 at room temperature, which is 53% higher than that of the SPEEK control membrane (0.043 S cm-1). The composite membrane also showed stable proton conductivity after being immersed in water for 2000 h. Therefore, our study demonstrates that preparing water-insoluble nanofillers containing HPW components through sintering is a promising approach.

Accuracy of detecting burst of the lateral wall in intertrochanteric hip fractures with plain radiographs: Is postoperative CT necessary?

Background: Postoperative burst of the lateral femoral wall is thought to be the main predictor of reoperation for intertrochanteric fractures, which is routinely evaluated using plain radiographs. We retrospectively compared computed tomography (CT) scans and radiographs regarding the ability to detect burst of the lateral wall. We also investigated whether intramedullary nails may cause iatrogenic burst of the lateral wall. Methods: From January 2010 to December 2021, patients aged 65 years and older who undergone intertrochanteric fractures treated with the proximal femoral nail antirotation 2 (PFNA-Ⅱ) were included. The incidence of burst of the lateral wall was evaluated with two different imaging modalities by two observers. Two rounds of evaluation were performed: (1) with plain radiographs alone; and (2) with CT scans combined with radiographs. Interobserver and intraobserver agreement (κ value) for evaluation of the lateral wall burst was assessed. Results: A total of 1507 patients were included (362 males and 1145 females). Compared with radiographs alone (12.0 %, 181/1507 patients), a higher rate of lateral wall burst was found by CT scans combined with radiographs (72.9 %, 1098/1507 patients) for observer 1 at first reading (P < 0.001). Similar results were seen in other evaluations. Interobserver and intraobserver agreement was substantial for radiographs alone (κ, 0.659-0.727) and almost perfect for CT scans combined with radiographs (κ, 0.847-0.926). Conclusions: Computed tomography combined with radiographs is superior to radiographs alone for detecting burst of the lateral wall after intertrochanteric fracture fixation. Additionally, PFNA-Ⅱ could cause iatrogenic burst of the lateral wall for intertrochanteric fractures in the elderly.

Design of well-matched end-structure of anatomical proximal femoral locking plate based on computer-assisted imaging combined with 3D printing technology: a quality improvement study.

BACKGROUND: The extramedullary locking plate system was the common internal fixation method for hip fractures. However, common plates were poorly matched to femur, which was because they were designed based on anatomical parameters of the Western populations. Therefore, the aim was to design an end-structure of the anatomical proximal femoral locking plate that closely matched the anatomy of the Chinese population. MATERIALS AND METHODS: From January 2010 to December 2021, consecutive patients aged 18 years and older who underwent a full-length computed tomography scan of the femur were included. The end-structure (male and female model) of the anatomical proximal femoral locking plate was designed based on anatomical parameters of femurs that were measured in three-dimensional space using computer-assisted virtual technology. The match degree between the end-structure and femur were evaluated. Inter-observer and intra-observer agreement for the evaluation of match degree was assessed. The matching evaluation based on a three-dimensional printing model was regarded as the gold standard to assess the reliability. RESULTS: A total of 1672 patients were included, with 701 men and 971 women. Significant differences were seen between male and female for all parameters of the proximal femur (all P <0.001). All match degree of end-structure was over 90%. Inter-observer and intra-observer agreement was almost perfect (all kappa value, >0.81). The sensitivity, specificity, and percentage of correct interpretation of matching evaluation in the computer-assisted virtual model was all greater than 95%. From femur reconstruction to completion of internal fixation matching, the process takes about 3 min. Moreover, reconstruction, measurement, and matching were all completed in one system. CONCLUSIONS: The results showed that based on the larger sample of femoral anatomical parameters, a highly matching end-structure of anatomical proximal femoral locking plate for Chinese population could be designed with use of computer-assisted imaging technology.

Characteristics, sources and risk assessments of heavy metal pollution in soils of typical chlor-alkali residue storage sites in northeastern China.

In this study, thirty-four soil samples from a typical chlor-alkali slag residue storage site near the city of Qiqihar in northeastern China were collected and their arsenic, cadmium, chromium, copper, mercury, nickel, lead and zinc concentrations were determined. Sources of these heavy metals were analyzed with a positive matrix factorization model, and the health risks associated with different pollution sources were calculated. The results showed that mercury was the main heavy metal pollutant at the site (maximum concentration of 112.19 mg.kg-1) and the soil was also contaminated with arsenic, copper and lead. The sources of eight heavy metals were: mixed oil refinery wastewater and parent material (arsenic, chromium, copper and lead), vinyl chloride waste source (mercury), parent material (cadmium, nickel and zinc). The average potential ecological risk of the soil was 22344.39, with vinyl chloride waste source contributing 99.85% of this risk. The average carcinogenic risk of a mixture of oil refinery wastewater and parent material for children and adults was 9.06×10-6 and 6.36×10-6, respectively, accounting for 99.9% (children) and 99.48% (adults) of the total average carcinogenic risk. The average hazard index of vinyl chloride waste source for children and adults was 0.6 and 0.38, respectively, which accounted for 64.13% (children) and 52.34% (adults) of the total hazard index. These results provide a reference for soil pollution risk assessments at this type of site.

Source Apportionment of Heavy Metals Based on Multiple Approaches for a Proposed Subway Line in the Southeast Industrial District of Beijing, China.

Apportioning the sources of heavy metals (HMs) in soil is of great importance for pollution control. A total of 64 soil samples from 13 sample points at depths of 0-21 m were collected along a proposed subway line in the southeast industrial district of Beijing. The concentrations, distribution characteristics, and sources of eight HMs were investigated. The results showed that the concentrations of Hg, Cd, Cu, Pb, As, and Zn in the topsoil (0-2 m) exceeded the Beijing soil background values. Three sources were identified and their respective contribution rates calculated for each of the HMs using multiple approaches, including correlation analysis (CA), top enrichment factor (TEF), principal component analysis (PCA), and positive matrix factor (PMF) methods. As (63.11%), Cr (61.67%), and Ni (70.80%) mainly originated from natural sources; Hg (97.0%) was dominated by fossil fuel combustion and atmospheric deposition sources; and Zn (72.80%), Pb (69.75%), Cu (65.36%) and Cd (53.08%) were related to traffic sources. Multiple approaches were demonstrated to be effective for HM source apportionment in soil, whilst the results using PMF were clearer and more complete. This work could provide evidence for the selection of reasonable methods to deal with soils excavated during subway construction, avoiding the over-remediation of the soils with heavy metals coming from natural sources.

Anchoring Water Soluble Phosphotungstic Acid by Hybrid Fillers to Construct Three-Dimensional Proton Transport Networks.

Phosphotungstic acid (HPW)-filled composite proton exchange membranes possess high proton conductivity under low relative humidity (RH). However, the leaching of HPW limits their wide application. Herein, we propose a novel approach for anchoring water soluble phosphotungstic acid (HPW) by polydopamine (PDA) coated graphene oxide and halloysite nanotubes (DGO and DHNTs) in order to construct hybrid three-dimensional proton transport networks in a sulfonated poly(ether ether ketone) (SPEEK) membrane. The introduction of PDA on the surfaces of the hybrid fillers could provide hydroxyl groups and secondary amine groups to anchor HPW, resulting in the uniform dispersion of HPW in the SPEEK matrix. The SPEEK/DGO/DHNTs/HPW (90/5/5/60) composite membrane exhibited higher water uptake and much better conductivity than the SPEEK membrane at low relative humidity. The best conductivity reached wass 0.062 S cm-1 for the composite membrane, which is quite stable during the water immersion test.

Influence of Timing of Postoperative Weight-Bearing on Implant Failure Rate Among Older Patients With Intertrochanteric Hip Fractures: A Propensity Score Matching Cohort Study.

Introduction: The purpose of this study was to determine whether immediate weight-bearing as tolerated increased the risk of implant failure and decreased functional outcomes compared with restricted weight-bearing. Methods: From January 2010 to December 2018, 1,125 consecutive patients (≥65 years) with intertrochanteric fractures were identified. Of them, 130 patients were excluded, resulting in 995 patients in final cohort (563 receiving immediate weight-bearing and 432 receiving restricted weight-bearing). Propensity score (PS) matching yielded 403 patient pairs. Primary outcome was implant failure at 12 months. Secondary outcomes were implant failure at 3 months, functional outcomes at 12 months, and time to full weight-bearing. Results: Among 806 patients who were matched by PS, the mean age was 77.8 years (SD, 7.6), and 603 patients (74.8%) were women. After matching, there was no significant difference between immediate (10.0% [39/389]) and restricted (9.1%, [35/385]) weight-bearing for implant failure at 12 months (absolute risk difference, 0.93% [95% CI, -3.26 to 5.13%]; RR, 1.11 [95% CI, 0.69 to 1.80]; p = 0.66). Additionally, no significant difference was seen for implant failure at 3 months and functional outcomes at 12 months. Patients with immediate weight-bearing had shorter time to full weight-bearing (mean [SD], 87.6 days [7.5] vs. 121.3 days [11.0]; mean difference, -33.7 [95% CI, -35.0 to -32.3]; p < 0.001). Conclusions: Among older patients with intertrochanteric fractures, receipt of immediate weight-bearing as tolerated did not increase risks of implant failure or worsen functional outcomes compared with receipt of restricted weight-bearing. However, patients receiving immediate weight-bearing had a shorter time to full weight-bearing.