Metal-Organic Framework as a New Type of Magnetothermally-Triggered On-Demand Release Carrier

The development of external stimuli-controlled payload systems has been sought after with increasing interest toward magnetothermally-triggered drug release (MTDR) carriers due to their non-invasive features. However, current MTDR carriers present several limitations, such as poor heating efficiency caused by the aggregation of iron oxide nanoparticles (IONPs) or the presence of antiferromagnetic phases which affect their efficiency. Herein, a novel MTDR carrier is developed using a controlled encapsulation method that fully fixes and confines IONPs of various sizes within the metal-organic frameworks (MOFs). This novel carrier preserves the MOF's morphology, porosity, and IONP segregation, while enhances heating efficiency through the oxidation of antiferromagnetic phases in IONPs during encapsulation. It also features a magnetothermally-responsive nanobrush that is stimulated by an alternating magnetic field to enable on-demand drug release. The novel carrier shows improved heating, which has potential applications as contrast agents and for combined chemo and magnetic hyperthermia therapy. It holds a great promise for magneto-thermally modulated drug dosing at tumor sites, making it an exciting avenue for cancer treatment.

An Efficient Transformer Model for Synthesizing Dual Energy CT from Single Energy Scanner

PURPOSE/OBJECTIVE(S)

Dual-energy CT can be used to optimize radiation treatment. Recently, deep learning has been demonstrated to synthesize high-energy CT images from low-energy ones for dose reduction and lower CT system burden. As the state-of-the-art deep learning architecture, the computation burden of Transformer increases quadratically with the feature size, making the model training resource-demanding or even infeasible. Here, we introduce an efficient transformer for the balance between CT image synthesis quality and computational burden.

MATERIALS/METHODS

The model is a U-shape deep neural network with encoders and decoders built by Transformer blocks. The model input is low-energy 100kVp CT image and the output is high-energy 140kVp one. Each block has a Self Channel Correlation Unit (SCCU) and a Self Spatial Attention Unit (SSAU). Local shortcuts are applied for both units. Under-sampling operation achieved by pixel shuffling is used to obtain multi-scale feature maps, and the transformer block is applied on each feature scale. Symmetric skip connection sending features from shallow layers to deep layers, thus an additional 1 × 1 convolution is used for feature fusion in each decoder. In a SCCU, the feature is first mapped to one Query, one Key, and one Value. Then the Query and the Key tensors perform matrix multiplication to compute cross covariance of feature channels. The channel correlation score can be obtained by normalization of the covariance, and it is used to weight the Value tensor. As a result, the model complexity only increases linearly with the feature size. Besides the channel weighting, we enhance spatial information using SSAU, where the feature is mapped to two tensors. One tensor after activation is used to point-wisely calibrate another tensor. Additional Transformer blocks are cascaded to the last decoder for feature refinement. Because of the structure similarity of low- and high-energy CT images, a global shortcut is used to ease model training. Clinical iodine contrast-enhanced dual energy CT image datasets of 19 patients are used in this study. The dual-energy scanning is performed by a SOMATOM Definition Flash DECT scanner. We split the datasets into training dataset of 15 patients, validation dataset of 1 patient, and testing dataset of 3 patients. The image size is 512 × 512 with pixel size 0.5 × 0.5 mm2.

RESULTS

The U-Net model with 1.95M parameters and 44.87G FLOPS achieved the averaged PSNR value of 44.55 dB (s.t.d. 1.34) and averaged RMSE value of 0.0060 (s.t.d. 0.001). In comparison, our efficient Transformer with 1.408M parameters and 31.375G FLOPS achieved the averaged PSNR value of 44.78 dB (s.t.d. 1.37) and RMSE value of 0.0059 (s.t.d. 0.001), demonstrating our model has better performance with small model size and less computation.

CONCLUSION

The efficient Transformer model allows high-resolution CT image synthesis with small model scale and computation burden from low-energy CT image.

Self-Limiting Sub-5 nm Nanodiamonds by Geochemistry-Inspired Synthesis

Controlling diamond structures with nanometer precision is fundamentally challenging owing to their extreme and far-from-equilibrium synthetic conditions. State-of-the-art techniques, including detonation, chemical vapor deposition, mechanical grinding, and high-pressure-high-temperature synthesis, yield nanodiamond particles with a broad distribution of sizes. Despite many efforts, the direct synthesis of nanodiamonds with precisely controlled diameters remains elusive. Here the geochemistry-inspired synthesis of sub-5 nm nanodiamonds with sub-nanometer size deviation is described. High-pressure-high-temperature treatment of uniform iron carbide nanoparticles embedded in iron oxide matrices yields nanodiamonds with tunable diameters down to 2.13 and 0.22 nm standard deviation. A self-limiting, redox-driven, and diffusion-controlled solid-state reaction mechanism is proposed and supported by in situ X-ray diffraction, ex situ characterizations, and computational modeling. This work provides a unique mechanism for the precise control of nanostructured diamonds under extreme conditions and paves the road for the full realization of their potential in emerging technologies.

[Research of artificial intelligence-based clinical decision support system for primary hepatocellular carcinoma]

Objective: To apply artificial intelligence technology in clinical real-world data of patients with primary hepatocellular carcinoma, explore the precise treatment of disease and build up artificial intelligence-based clinical decision support system. Methods: A total of 5 642 patients with primary hepatocellular carcinoma admitted to West China Hospital from July 2004 to June 2016 with complete follow-up records were included in the study. A merged model composed of multiple sub-classifiers was adopted to calculate therapy recommendation coefficient, and receiver operator characteristic curve was analyzed. Survival risk and recurrence risk were predicted by DeepSurv algorithm, and Kaplan-Meier survival curves were further compared among low, middle and high risk groups. Siamese-Net was applied to find similar patients. Results: The Top-1 and Top-2 accuracy of therapy recommendation coefficient reached 82.36% and 94.13% respectively. In internal verification of West China Hospital, the above-mentioned value reached 95.10% in accordance with multi-disciplinary team results. The C-index derived from survival risk model was 0.735 (95%CI:0.70-0.77), and the difference of Kaplan-Meier in pairwise comparison was of statistical significance under log-rank test (P<0.001). Meanwhile, the C-index derived from recurrence risk model was 0.705 (95%CI:0.68-0.73), and the difference of Kaplan-Meier in pairwise comparison was of statistical significance under log-rank test (P<0.001). Conclusions: The artificial intelligence-based clinical decision support system for primary hepatocellular carcinoma has can accurately make therapy recommendation and prognosis prediction for primary hepatocellular carcinoma.

[Early diagnosis and treatment for burn complicated with severe paroxysmal sympathetic hyper-activity]

Objective: To investigate the early diagnosis and treatment for burn complicated with severe paroxysmal sympathetic hyperactivity (PSH). Methods: Medical records of patients with burn complicated with severe PSH, admitted to our department from April 2016 to March 2019 and meeting the inclusion criteria were analyzed retrospectively. There were 4 males and 1 female, aged 17 months to 39 years, with an average of (21±16) years. During occurrence of PSH, the vital signs of patients were routinely monitored and oxygen were given. Other treatment included central venous catheterization and infusion of electrolyte solution, infusion of plasma according to patients' condition, use of opioid analgesics and benzodiazepine sedatives, physical cooling and drug cooling, and establishment or maintenance of artificial airway and use of ventilator. Heart rate was controlled below 120 beats per minute in adults and 140 beats per minute in children with comprehensive treatment dominated by analgesia and sedation. Besides, single or multiple vasoactive agents, even in large doses were used to maintain normal blood pressure of patients. The occurrence characteristics, time, and treatment outcome of PSH were analyzed. Results: PSH happened rapidly, with a sharp increase in several minutes to dozens of minutes. Five patients were with symptoms such as high body temperature, shortness of breath, very fast heart rate, normal or elevated systolic blood pressure, hyperhidrosis, and dystonia at the onset. The symptoms occurred simultaneously or successively. According to the Clinical Feature Scale, the above-mentioned 6 indexes achieved the highest score of 3 points except of systolic blood pressure. Four patients showed dilated pupils and impaired consciousness. Among the patients, PSH occurred in the acute exudation stage in 3 patients, in the fluid reabsorption stage in 1 patient, and in the late repair stage in 1 patient. PSH of patients lasted for 3 hours to 12 days. The symptoms of 4 patients were effectively controlled, and 1 patient died of deterioration. No PSH occurred in the cured patients during follow-up of 3 to 14 months. Conclusions: Burn complicated with PSH can occur at any time before wound repair and in patients with different injury conditions. The causes of PSH include sudden burn, persistent pain, fright and fear, strange environment, low blood volume, and other adverse stimuli, and PSH is more likely to occur in children with underdeveloped brain function. Intravenous infusion of analgesics sedatives, physical therapy and medication to lower body temperature, stabilizing blood pressure and respiration are effective measures to treat PSH. PSH should be distinguished from the common complications of burns, such as sepsis, cerebral edema, hyperpyretic convulsion, transfusion response, stress disorder, etc.

[The downbeat nystagmus in 2 cases with unilateral Meniere's disease]

We retrospectively analyzed 2 patients of unilateral Meniere's disease with downbeat nystagmus. Audiometric test, the Dix-Hallpike maneuver and the supine roll test were performed. Both patients presented with spontaneous nystagmus with downbeat components, and downbeat components were exaggerated by Dix-Hallpike maneuver. Spontaneous and positional nystagmus with downbeat component can occur in Meniere's disease, which may be resulted from excitation of three semicircular canals.

[One case of severely burned patient complicated by acute hemorrhagic necrotizing enteritis and fungal infection]

One severely burned patient, caused by heat lead slag and combined with shock, was hospitalized in our burn unit on 2nd June, 2016. The patient received treatments including anti-shock, intensive care, anti-infection, and organ protection. On post injury day 16, the patient suffered outbreak of acute hemorrhagic necrotizing enteritis after eating dumplings. Plasma and albumin were given, octreotide was intravenously infused to inhibit the secretion of intestinal fluid, the broad-spectrum antibiotics were used for anti-infection, abdominal puncture and drainage were performed, sodium tanshinone ⅡA sulfonate was applied to improve the intestinal microcirculation, ulinastatin was applied to alleviate inflammatory reaction, somatostatin was given to reduce intestinal bleeding, and voriconazole was given for antifungal treatment. The patient gradually recovered and was finally cured and discharged. Among critically ill patients, gastrointestinal tract is not only the initiating organ of sepsis, but also one of the target organs which can be easily damaged during sepsis. This case reminds us the importance of gastrointestinal management in severely burned patients.

[Validation of the Chinese version of the uterine fibroid symptom and health-related quality of life]

Objective: To evaluate the reliability and validity of the Chinese version of the uterine fibroid symptom and health-related quality of life (UFS-QOL) in patients with uterine fibroid. Methods: The original English UFS-QOL was translated into Chinese and linguistically validated following the cross-cultural adaptation of health-related quality of life measures. Patients recruited randomly from Peking Union Medical College Hospital from June 2013 to December 2016 were scheduled for two visits with 2 weeks apart, and they were surveyed through the Chinese version of UFS-QOL and short-form 12-item health survey (SF-12). The reliability and validity of the Chinese version of UFS-QOL were evaluated. Results: A total of 190 uterine fibroid patients who met the criteria participated this study. The Chinese version of UFS-QOL had a high internal consistency (Cronbach's α, uterine fibroid symptom severity scale:0.912, health-related quality of life scale: 0.976) and high test-retest reliability (intraclass correlation coefficient, 0.572-0.951, P<0.01). The symptom severity scores and SF-12 scores were negatively correlated (r=-0.813, P<0.01); the health-related quality of life scores and SF-12 scores were positively correlated (r=0.620, P<0.01). The factor analysis showed good construct validity. Conclusion: Psychometric testing supports the reliability and validity of the Chinese version of UFS-QOL as an disease-specific measure of health-related quality of life.