Anterior atlantoaxial motion preservation fixation technique for axis complex fractures (odontoid process with Hangman's fractures) and technique notes.

This study aims to investigate the feasibility and efficacy of anterior atlantoaxial motion preservation fixation (AMPF) in treating axis complex fractures involving the odontoid process fracture and Hangman's fractures with C2/3 instability. A retrospective study was conducted on eight patients who underwent AMPF for axis complex fractures at the General Hospital of Central Theater Command from February 2004 to October 2021. The types of axis injuries, reasons for injuries, surgery time, intraoperative blood loss, spinal cord injury classification (American Spinal Injury Association, ASIA), as well as complications and technical notes, were documented. This study included eight cases of type II Hangman's fracture, five cases of type II and three cases of type III odontoid process fracture. Five patients experienced traffic accidents, while three patients experienced falling injuries. All patients underwent AMPF surgery with an average intraoperative blood loss of 288.75 mL and a duration of 174.5 min. Two patients experienced dysphagia 1 month after surgery. The patients were followed up for an average of 15.63 months. One case improved from C to E in terms of neurological condition, three cases improved from D to E, and four cases remained at E. Bony fusion and Atlantoaxial Motion Preservation were successfully achieved for all eight patients. AMPF is a feasible and effective way for simultaneous odontoid process fracture and Hangman's fractures with C2/3 instability, while preserving atlantoaxial movement.

Semantic segmentation for tooth cracks using improved DeepLabv3+ model.

Objective: Accurate and prompt detection of cracked teeth plays a critical role for human oral health. The aim of this paper is to evaluate the performance of a tooth crack segmentation model (namely, FDB-DeepLabv3+) on optical microscopic images. Method: The FDB-DeepLabv3+ model proposed here improves feature learning by replacing the backbone with ResNet50. Feature pyramid network (FPN) is introduced to fuse muti-level features. Densely linked atrous spatial pyramid pooling (Dense ASPP) is applied to achieve denser pixel sampling and wider receptive field. Bottleneck attention module (BAM) is embedded to enhance local feature extraction. Results: Through testing on a self-made hidden cracked tooth dataset, the proposed method outperforms four classical networks (FCN, U-Net, SegNet, DeepLabv3+) on segmentation results in terms of mean pixel accuracy (MPA) and mean intersection over union (MIoU). The network achieves an increase of 11.41% in MPA and 12.14% in MIoU compared to DeepLabv3+. Ablation experiments shows that all the modifications are beneficial. Conclusion: An improved network is designed for segmenting tooth surface cracks with good overall performance and robustness, which may hold significant potential in computer-aided diagnosis of cracked teeth.

Plant-inspired multifunctional fluorescent cellulose nanocrystals intelligent nanocomposite hydrogel.

Intelligent hydrogel has great application potentials in flexible sensing and artificial intelligence devices due to its intrinsic characteristics. However, developing an intelligent hydrogel with favorable properties including high strength, superior toughness, excellent conductivity and ionic sensing via a facile route is still a challenge. Herein, inspired by biologically chelating interactions of phytic acid (PA) in plants, a plant-inspired versatile intelligent nanocomposite hydrogel was readily fabricated by incorporating PA into the interface of fluorescent cellulose nanocrystals (F-CNC). Under PA "molecular bridge", the hydrogel simultaneously realized superflexibility (1000 %), high strength, superb self-healing ability, remarkable fluorescence and chloride ion sensibility as well as good ionic conductivity (2.4 S/m). The hydrogel could be assembled as a flexible sensor for real-time monitoring of human motion with excellent sensitivity and stability since high sensitivity toward both strain and pressure. F-CNC acted as a functional trigger could confer the hydrogel good fluorescence and high sensitivity toward chloride ion. This design confirms the synergy of F-CNC in boosting strength, ionic sensing, and ionic conductivity, addressing a long-standing dilemma among strength, stretchability, and sensitivity for intelligent hydrogel. The one-step incorporating tactic under mild ambient conditions may open an innovative avenue for the construction of intelligent hydrogel with novel properties.

One-pot synthesis of aminated cellulose nanofibers by "biological grinding" for enhanced thermal conductivity nanocomposites.

Aminated cellulose nanofibers (A-CNF) with high thermostability (>350 ℃), high crystallinity (81.25 %), and high dispersion stability were extracted from "biological grinding" biomass through one-pot microwave-hydrothermal synthesis. Worm-eaten wood powder (WWP) as the product of "biological grinding" by borers is a desirable lignocellulose for fabricating A-CNF in a green and cost-effective way since it is a well-milled fine powder with dimension of dozens of microns, which can be used directly, saving energy and labor. Generated A-CNF proved to be an excellent reinforcing and curing agent for constructing high performance epoxy nanocomposites. The nanocomposites exhibited a thermal conductivity enhancement of about 120 %, coefficient of thermal expansion reduction of 78 %, and Young's modulus increase of 108 % at a low A-CNF loading of 1 wt.%, demonstrating their remarkable reinforcing potential and effective stress transfer behavior. The process proposed herein might help to bridge a closed-loop carbon cycle in the whole production-utilization of biomass.

Report of four cases of crowned dens syndrome: Clinical presentation, CT findings and treatment.

The clinical manifestations of crowned dens syndrome (CDS) include acute neck pain and neck stiffness accompanied by restricted cervical range of motion. CDS is frequently misdiagnosed as meningitis, epidural abscess, rheumatoid arthritis, rheumatoid polymyalgia, giant cell arteritis, cervical spondylosis or metastatic bone tumor, and the incidence of CDS appears to be underestimated. The present study reported on four cases of CDS diagnosed by CT. They included one male and three females, aged from 67 to 78 years, and their major symptoms were acute neck pain and restricted cervical range of motion. Serum C-reactive protein levels and erythrocyte sedimentation rate were significantly increased in all cases. Cervical CT scan revealed calcified deposits surrounding the odontoid process in all cases. Non-steroidal anti-inflammatory drugs (NSAIDs) markedly reduced the levels of inflammatory indicators and rapidly relieved the symptoms. CT scan is considered the gold standard for CDS diagnosis, which may demonstrate calcification around the odontoid process. The patients' symptoms may be improved by treatment with NSAIDs.

Ultrasonication-assisted manufacture of cellulose nanocrystals esterified with acetic acid.

Esterified cellulose nanocrystals (E-CNCs) are cellulose derivatives that could be applied in biomedical and chemical industries. E-CNCs were prepared with cellulose pulp using a mixture of 17.5M acetic and 18.4M sulfuric acid with the aid of ultrasonication. The effects of esterification time (3-7h), ultrasonication time (with a frequency of 40 kHz, 0 to 6h) and temperature (68-75 °C) on the yield and degree of substitution (DS) of E-CNCs were evaluated. The sample obtained without ultrasonication had the lowest yield and DS value of 48.16% and 0.22, respectively, whereas ultrasonication for 5h at 70 °C resulted in a yield of 85.38% and a DS value of 0.46. Characterization indicated the successful esterification of hydroxyl groups of cellulose, and the width of rod-shaped E-CNCs was from 10 to 100 nm. The study provides a simple and convenient method to manufacture E-CNCs.

Preparation, characterization and optimization of nanocellulose whiskers by simultaneously ultrasonic wave and microwave assisted.

Simultaneously ultrasonic wave and microwave assisted technique (SUMAT), as a method of process intensification, was first applied to the preparation of nanocellulose whiskers (NCWs) from filter paper by sulfuric acid hydrolysis. The effects of temperature, sulfuric acid concentration, and mass of raw material and time on the yield of NCWs were investigated by single-factor experiments, and the preparation conditions were optimized with response surface methodology. The obtained NCWs were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermal gravimetry. The results showed NCWs were facilely prepared by using SUMAT. However, some harsh reaction conditions such as high temperature, strong acidity and long time treatment easily induced the reduction of the yield of NCWs. Under the optimal conditions, the yield and the crystallinity of NCWs with the crystal form of cellulose Iα is 85.75% and 80%, respectively.