Tracking and navigation of a microswarm under laser speckle contrast imaging for targeted delivery.

Micro/nanorobotic swarms consisting of numerous tiny building blocks show great potential in biomedical applications because of their collective active delivery ability, enhanced imaging contrast, and environment-adaptive capability. However, in vivo real-time imaging and tracking of micro/nanorobotic swarms remain a challenge, considering the limited imaging size and spatial-temporal resolution of current imaging modalities. Here, we propose a strategy that enables real-time tracking and navigation of a microswarm in stagnant and flowing blood environments by using laser speckle contrast imaging (LSCI), featuring full-field imaging, high temporal-spatial resolution, and noninvasiveness. The change in dynamic convection induced by the microswarm can be quantitatively investigated by analyzing the perfusion unit (PU) distribution, offering an alternative approach to investigate the swarm behavior and its interaction with various blood environments. Both the microswarm and surrounding environment were monitored and imaged by LSCI in real time, and the images were further analyzed for simultaneous swarm tracking and navigation in the complex vascular system. Moreover, our strategy realized real-time tracking and delivery of a microswarm in vivo, showing promising potential for LSCI-guided active delivery of microswarm in the vascular system.

tPA-anchored nanorobots for in vivo arterial recanalization at submillimeter-scale segments.

Micro/nanorobots provide a promising approach for intravascular therapy with high precision. However, blood vessel is a highly complex system, and performing interventional therapy in those submillimeter segments remains challenging. While micro/nanorobots can enter submillimeter segments, they may still comprise nonbiodegradable parts, posing a considerable challenge for post-use removal. Here, we developed a retrievable magnetic colloidal microswarm, composed of tPA-anchored Fe3O4@mSiO2 nanorobots (tPA-nbots), to archive tPA-mediated thrombolysis under balloon catheter-assisted magnetic actuation with x-ray fluoroscopy imaging system (CMAFIS). By deploying tPA-nbot transcatheter to the vicinity of the thrombus, the tPA-nbot microswarms were magnetically actuated to the blood clot at the submillimeter vessels with high precision. After thrombolysis, the tPA-nbots can be retrieved via the CMAFIS, as demonstrated in ex vivo organ of human placenta and in vivo carotid artery of rabbit. The proposed colloidal microswarm provides a promising robotic tool with high spatial precision for enhanced thrombolysis with low side effects.

The Hong Kong consensus statements on unresectable hepatocellular carcinoma: narrative review and update for 2021.

Background and Objective: Hong Kong, like many parts of Asia, faces a high burden of hepatocellular carcinoma (HCC) caused by high endemic rates of hepatitis B virus infection. Hong Kong clinicians have developed a high level of expertise in HCC treatment across surgical, transarterial, ablative, radiotherapeutic and systemic modalities. This publication summarizes the latest evidence-based recommendations on how these modalities should be used. Methods: In two meetings held in 2020, a multidisciplinary panel of surgeons, oncologists and interventional radiologists performed a narrative review of evidence on the management of HCC, with an emphasis on treatment of HCC not amenable to surgical resection. Close attention was paid to new evidence published since the previous version of these statements in 2018. Key Content and Findings: The expert panel has formulated 60 consensus statements to guide the staging and treatment of unresectable HCC. Since the previous version of these statements, considerable additions have been made to the recommendations on use of targeted therapies and immunotherapies because of the large volume of new evidence. Conclusions: Our consensus statements offer guidance on how to select HCC patients for surgical or non-surgical treatment and for choosing among non-surgical modalities for patients who are not candidates for resection. In particular, there is a need for more evidence to aid physicians in the selection of second-line systemic therapies, as currently most data are limited to patients with disease progression on first-line sorafenib.

Swarming self-adhesive microgels enabled aneurysm on-demand embolization in physiological blood flow.

The recent rise of swarming microrobotics offers great promise in the revolution of minimally invasive embolization procedure for treating aneurysm. However, targeted embolization treatment of aneurysm using microrobots has significant challenges in the delivery capability and filling controllability. Here, we develop an interventional catheterization-integrated swarming microrobotic platform for aneurysm on-demand embolization in physiological blood flow. A pH-responsive self-healing hydrogel doped with magnetic and imaging agents is developed as the embolic microgels, which enables long-term self-adhesion under biological condition in a controllable manner. The embolization strategy is initiated by catheter-assisted deployment of swarming microgels, followed by the application of external magnetic field for targeted aggregation of microrobots into aneurysm sac under the real-time guidance of ultrasound and fluoroscopy imaging. Mild acidic stimulus is applied to trigger the welding of microgels with satisfactory bio-/hemocompatibility and physical stability and realize complete embolization. Our work presents a promising connection between the design and control of microrobotic swarms toward practical applications in dynamic environments.

Assessing the ecological loss of mining areas in Taiwan.

Mines are mostly located in the mountains and national forestlands in Taiwan. The development and use of mines have severely damaged the environment. Despite the long history of mining, the value of forest ecological services lost during mining operations have not yet been incorporated into the expenses borne by miners, and miners are not liable for compensation for ecological damage. This study evaluated the forest ecosystem service benefits lost since mining began, with the aim of providing future reference for calculating ecological damage related to mining. We investigated Mount Taibai mines in Yilan (northeast Taiwan) and Mount Yongshi mines in Hualian (east Taiwan), which are richly forested areas. According to Article 13 of the Mining Act in Taiwan, mining rights have a limitation of 20 years, and the two mines in this study have been in operation for 20 years. By using four ecological services-forest production, carbon sequestration, water resource replenishment, and forest recreation-we estimated the loss of ecological values in both mining regions. The result indicated that the loss of total forest production benefits over 20 years was 7,498.6 k New Taiwanese dollars (NTD) in Mount Taibai mines and 6,543.1 k NTD for Mount Yongshi mines, while the loss for the total carbon sequestration benefits over 20 years was 19,950 k NTD in Mount Taibai mines and 17,400 k NTD in Mount Yongshi mines. The loss of value for the total water conservation benefits over 20 years was 11,160 k NTD in Mount Taibai mines and 5,070 k NTD in Mount Yongshi mines. The loss value of forest recreation over 20 years was 1,443,855 k NTD for the two mines.

Detecting Early-Stage Liver Fibrosis Using Macromolecular Proton Fraction Mapping Based on Spin-Lock MRI: Preliminary Observations.

BACKGROUND: Liver fibrosis is characterized by macromolecule depositions. Recently, a novel technology termed macromolecular proton fraction quantification based on spin-lock magnetic resonance imaging (MPF-SL) is reported to measure macromolecule levels. HYPOTHESIS: MPF-SL can detect early-stage liver fibrosis by measuring macromolecule levels in the liver. STUDY TYPE: Retrospective. SUBJECTS: Fifty-five participants, including 22 with no fibrosis (F0) and 33 with early-stage fibrosis (F1-2), were recruited. FIELD STRENGTH/SEQUENCE: 3 T; two-dimensional (2D) MPF-SL turbo spin-echo sequence, 2D spin-lock T1rho turbo spin-echo sequence, and multi-slice 2D gradient echo sequence. ASSESSMENT: Macromolecular proton fraction (MPF), T1rho, liver iron concentration (LIC), and fat fraction (FF) biomarkers were quantified within regions of interest. STATISTICAL TESTS: Group comparison of the biomarkers using Mann-Whitney U tests; correlation between the biomarkers assessed using Spearman's rank correlation coefficient and linear regression with goodness-of-fit; fibrosis stage differentiation using receiver operating characteristic curve (ROC) analysis. P-value < 0.05 was considered statistically significant. RESULTS: Average T1rho was 41.76 ± 2.94 msec for F0 and 41.15 ± 3.73 msec for F1-2 (P = 0.60). T1rho showed nonsignificant correlation with either liver fibrosis (ρ = -0.07; P = 0.61) or FF (ρ = -0.14; P = 0.35) but indicated a negative correlation with LIC (ρ = -0.66). MPF was 4.73 ± 0.45% and 5.65 ± 0.81% for F0 and F1-2 participants, respectively. MPF showed a positive correlation with liver fibrosis (ρ = 0.59), and no significant correlations with LIC (ρ = 0.02; P = 0.89) or FF (ρ = 0.05; P = 0.72). The area under the ROC curve was 0.85 (95% confidence interval [CI] 0.75-0.95) and 0.55 (95% CI 0.39-0.71; P = 0.55) for MPF and T1rho to discriminate between F0 and F1-2 fibrosis, respectively. DATA CONCLUSION: MPF-SL has the potential to diagnose early-stage liver fibrosis and does not appear to be confounded by either LIC or FF. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.

Uncertainty-aware self-supervised neural network for liverT1ρmapping with relaxation constraint.

Objective.T1ρmapping is a promising quantitative MRI technique for the non-invasive assessment of tissue properties. Learning-based approaches can mapT1ρfrom a reduced number ofT1ρweighted images but requires significant amounts of high-quality training data. Moreover, existing methods do not provide the confidence level of theT1ρestimation. We aim to develop a learning-based liverT1ρmapping approach that can mapT1ρwith a reduced number of images and provide uncertainty estimation.Approach. We proposed a self-supervised neural network that learns aT1ρmapping using the relaxation constraint in the learning process. Epistemic uncertainty and aleatoric uncertainty are modelled for theT1ρquantification network to provide a Bayesian confidence estimation of theT1ρmapping. The uncertainty estimation can also regularize the model to prevent it from learning imperfect data. Main results. We conducted experiments onT1ρdata collected from 52 patients with non-alcoholic fatty liver disease. The results showed that when only collecting twoT1ρ-weighted images, our method outperformed the existing methods forT1ρquantification of the liver. Our uncertainty estimation can further regularize the model to improve the performance of the model and it is consistent with the confidence level of liverT1ρvalues.Significance. Our method demonstrates the potential for accelerating theT1ρmapping of the liver by using a reduced number of images. It simultaneously provides uncertainty ofT1ρquantification which is desirable in clinical applications.

Midterm clinical outcome of a case of aortic arch aneurysm treated with a novel arch stentgraft system.

INTRODUCTION: Open surgery is the gold standard treatment for aortic arch disease. However, due to its complexity, open arch replacement is associated with considerable risk of mortality and morbidity. METHOD: We report a case of a 71-year-old gentleman with multiple comorbidities and symptomatic 7 cm aortic arch aneurysm who was treated with a single-stage carotid-carotid and left carotid-axillary bypass followed by zone 0 aortic arch stenting with bimodular Nexus™ stent graft. RESULTS: Post-operatively, the patient suffered from a minor stroke with full neurological recovery. Follow-up computed tomography of the aorta 3 years post-stenting showed excellent stent position with no endoleak and complete resolution of the saccular aneurysm. DISCUSSION: The midterm result of our patient who was successfully treated with an off-the-shelf single branch, bimodular stent graft system is excellent with complete resolution of the arch saccular aneurysm at 3-year after the operation.

Sustaining aviation workforce after the pandemic: Evidence from Hong Kong aviation students toward skills, specialised training, and career prospects through a mixed-method approach.

The aviation industry is in a recession with the rapid and immense outbreak of COVID-19 under globalisation. The future young aviation professionals might suffer from a 'career shock'. This study analysed the post-pandemic career prospects for Hong Kong aviation students using mixed-method research considering specialised and licensed training. We conducted a survey (N = 101) and focus group interviews (N = 6) to investigate students' perceived impediments and potential support from the institutions. Matt-Whitney U test is used to compare the perceptual difference in the impediments, career prospects, skills required, and institutional supports between (non-)specialised training students, (non-)engineering-related students, and (non-)final-year students. The results demonstrated no significant difference between students with and without specialised training. While final-year students perceive themselves as lacking more in terms of non-technical skills than non-final-year students, students are interested in broadening their career options to include airline operations, aircraft engineering and maintenance via acquiring a variety of emerging knowledge and technical skills. Given most studies focus on the recovery pattern of the aviation industry, this study is original in considering Hong Kong aviation students' career impediments and prospects using a mixed-method approach to provide policy insights.

Selective Internal Radiation Therapy with Yttrium-90 Resin Microspheres Followed by Gemcitabine plus Cisplatin for Unresectable Intrahepatic Cholangiocarcinoma: A Phase 2 Single-Arm Multicenter Clinical Trial.

Introduction: This investigator-initiated clinical trial aims to study the efficacy and safety of administering selective internal radiation therapy with resin yttrium-90 microspheres (SIRT) followed by standard chemotherapy in unresectable intrahepatic cholangiocarcinoma (ICC). Methods: A phase 2 single-arm multicenter study was conducted in patients with unresectable ICC (NCT02167711). SIRT was administered at dose of 120 Gy targeted at tumor followed by commencement of gemcitabine 1,000 mg/m2 and cisplatin 25 mg/m2 on days one and eight of a 21-day cycle. The primary endpoint was overall survival (OS), and the secondary endpoints include progression-free survival (PFS), response rate according to Response Evaluation Criteria in solid tumors 1.1, toxicity, and time from SIRT to commencement of chemotherapy. Results: Total 31 patients were screened and twenty-four were recruited. All patients completed SIRT and 16 of them underwent subsequent chemotherapy. The median cycle of chemotherapy was 5 (range: 1-8). The median OS was 13.6 months (95% CI: 5.4-21.6) for the intent-to-treat population. Among 16 patients undergoing chemotherapy, the median OS was 21.6 months (95% CI: 7.3-25.2) and the median PFS was 9 months (95% CI: 3.2-13.1). The response rate was 25% (95% CI: 3.8-46.2%), and the disease control rate was 75% (95% CI: 53.8-96.2%). No new safety signal was observed, with fewer than 10% of patients suffering from grade 3 or higher treatment-related adverse events. The median time from SIRT to chemotherapy was 29 (range: 7-42) days. Eight patients could not receive chemotherapy due to rapid progressive disease (n = 4), underlying treatment unrelated comorbidities (n = 2), and withdrawal of consent due to personal reasons (n = 2). Conclusions: Treatment of SIRT followed by standard gemcitabine and cisplatin chemotherapy is feasible and effective for unresectable ICC. Further studies are required to study the optimal sequence of SIRT and chemotherapy.

PHIL and Squid Embolization of Cerebral Arteriovenous Malformation: A Retrospective Case Series of 23 Patients.

Precipitating hydrophobic injectable liquid (PHIL; MicroVention, Aliso Viejo, CA, USA) and Squid (Balt, Irvine, CA, USA) are 2 newer liquid embolic agents used in endovascular embolization of cerebral arteriovenous malformation (AVM). This study aims to investigate and compare the effectiveness and safety profile of the 2 newer liquid embolic agents in the embolization of cerebral AVM. This is a retrospective study on all patients diagnosed with cerebral AVM undergoing endovascular embolization with liquid embolic agents PHIL and Squid admitted to the Division of Neurosurgery, Department of Surgery in Prince of Wales Hospital from January 2014 to June 2021. Twenty-three patients with cerebral AVM were treated with 34 sessions of endovascular embolization with either PHIL or Squid (17 sessions each) liquid embolic agents with a male to female ratio of 2.3:1 (male 16; female 7) and mean age of 44.6 (range, 12 to 67). The mean total nidus obliteration rate per session was 57% (range, 5% to 100%). Twenty-one patients (91.3%) received further embolization, stereotactic radiosurgery, or surgical excision after initial endovascular embolization. There were 2 morbidities (1 neurological and 1 non-neurological, 6%) and no mortalities (0%). All patients had static or improvement in modified Rankin Scale at 3 to 6 months at discharge. PHIL and Squid are effective and safe liquid embolic agents for endovascular embolization of cerebral AVM, achieving satisfactory nidal obliteration rates and patient functional outcomes.

Enhancing the MEP Coordination Process with BIM Technology and Management Strategies.

Building Information Modeling (BIM) has been increasingly used in coordinating the different mechanical, electrical, and plumbing (MEP) services in the construction industries. As the construction industries are slowly adapting to BIM, the use of 2D software may become obsolete in the future as MEP services are technically more complicated to coordinate, due to respective services' codes of practice to follow and limit ceiling height. The 3D MEP designs are easy to visualize before installing the respective MEP services on the construction site to prevent delay in the construction process. The aid of current advanced technology has brought BIM to the next level to reduce manual work through automation. Combining both innovative technology and suitable management methods not only improves the workflow in design coordination, but also decreases conflict on the construction site and lowers labor costs. Therefore, this paper tries to explore possible advance technology in BIM and management strategies that could help MEP services to increase productivity, accuracy, and efficiency with a lower cost of finalizing the design of the building. This will assist the contractors to complete construction works before the targeted schedule and meet the client's expectations.

Enhanced jet stream waviness induced by suppressed tropical Pacific convection during boreal summer.

Consensus on the cause of recent midlatitude circulation changes toward a wavier manner in the Northern Hemisphere has not been reached, albeit a number of studies collectively suggest that this phenomenon is driven by global warming and associated Arctic amplification. Here, through a fingerprint analysis of various global simulations and a tropical heating-imposed experiment, we suggest that the suppression of tropical convection along the Inter Tropical Convergence Zone induced by sea surface temperature (SST) cooling trends over the tropical Eastern Pacific contributed to the increased summertime midlatitude waviness in the past 40 years through the generation of a Rossby-wave-train propagating within the jet waveguide and the reduced north-south temperature gradient. This perspective indicates less of an influence from the Arctic amplification on the observed mid-latitude wave amplification than what was previously estimated. This study also emphasizes the need to better predict the tropical Pacific SST variability in order to project the summer jet waviness and consequent weather extremes.

Evolving ischemic stroke subtypes in 15 years: A hospital-based observational study.

BACKGROUND: Depicting the time trends of ischemic stroke subtypes may inform healthcare resource allocation on etiology-based stroke prevention and treatment. AIM: To reveal the evolving ischemic stroke subtypes from 2004 to 2018. METHODS: We determined the stroke etiologies of consecutive first-ever transient ischemic attack or ischemic stroke patients admitted to a regional hospital in Hong Kong from 2004 to 2018. We analyzed the age-standardized incidences and the two-year recurrence rate of major ischemic stroke subtypes. RESULTS: Among 6940 patients admitted from 2004 to 2018, age-standardized incidence of ischemic stroke declined from 187.0 to 127.4 per 100,000 population (p < 0.001), driven by the decrease in large artery disease (43.0-9.67 per 100,000 population (p < 0.001)), and small vessel disease (71.9-45.7 per 100,000 population (p < 0.001)). Age-standardized incidence of cardioembolic stroke did not change significantly (p = 0.2). Proportion of cardioembolic stroke increased from 20.4% in 2004-2006 to 29.3% in 2016-2018 (p < 0.001). Two-year recurrence rate of intracranial atherothrombotic stroke reduced from 19.3% to 5.1% (p < 0.001) with increased prescriptions of statin (p < 0.001) and dual antiplatelet therapy (p < 0.001). In parallel with increased anticoagulation use across the study period (p < 0.001), the two-year recurrence of AF-related stroke reduced from 18.9% to 6% (p < 0.001). CONCLUSION: Etiology-based risk factor control might have led to the diminishing stroke incidences related to atherosclerosis. To tackle the surge of AF-related strokes, arrhythmia screening, anticoagulation usage, and mechanical thrombectomy service should be reinforced. Comparable preventive strategies might alleviate the enormous stroke burden in mainland China.

Blood Flow Diversion Within Hepatocellular Carcinoma (HCC) after Selective Occlusion of Feeding Arteries (SOFA) and Feasibility of Utilizing the SOFA Technique in Transarterial Chemoembolization (SOFA-TACE).

PURPOSE: Arterial feeders supplying a hepatocellular carcinoma are known to be interconnected through the sinusoid-like tumor vasculature. It was observed angiographically that when one of the feeders is selectively catheterized for drug delivery in transarterial chemoembolization (TACE), the whole tumor vasculature will be filled up, if the arterial inflow from all the other feeders is temporarily arrested with selective occlusion of feeding arteries (SOFA) using an additional catheter (balloon catheter). The feasibility of using the SOFA technique in TACE (SOFA-TACE) is discussed. MATERIALS AND METHODS: In this prospective, monocentric feasibility study, with informed consent obtained, 8 consecutive patients of median age 64.5 years (60-68.8) and tumor dimension 4.7 cm (3.2-6.1), having specific tumor features (solitary, hypervascularity, well-defined, ≤ 7 cm, multiple tumor feeders), received SOFA-TACE using ethiodized oil-cisplatin suspension. Tumor response was assessed with 3-monthly CT using modified RECIST. RESULTS: A single tumor feeder was catheterized for drug delivery (8 cases). All other tumor feeders were successfully occluded with a balloon at one site (8 cases). Complete filling of the vasculature of the whole tumor was achieved in 7 of 8 cases with the SOFA technique as shown on arteriogram and CT, except in a case with an intratumoral septum. There was no complication. Surveillance CT (median 25 months, range 22-28) showed complete response in all cases. CONCLUSION: SOFA-TACE is feasible with reasonable safety and favorable treatment outcome; it may be a valuable technical option that may facilitate the procedures of selective TACE in technically challenging cases.

Comparison of Chemoembolization, Radioembolization, and Transarterial Ethanol Ablation for Huge Hepatocellular Carcinoma (≥ 10 cm) in Tumour Response and Long-Term Survival Outcome.

PURPOSE: To compare transarterial chemoembolization (TACE), transarterial radioembolization using Yttrium-90 (TARE), and transarterial ethanol ablation (TEA) for huge hepatocellular carcinoma (HCC) in treatment responses and long-term survival outcomes. MATERIALS AND METHODS: In this retrospective study approved by institutional committee, inclusion criteria were tumour ≥ 10 cm, newly diagnosed, treatment naïve, Child A, Performance Score 0 or 1, no venous invasion or extrahepatic disease on contrast-enhanced CT or MRI. There were 107 patients (Supportive Care [SC] 17, TACE 54, TARE 17, TEA 19). Survival outcomes of SC and TACE were compared (TACE selected as benchmark for transarterial treatments). Tumour response and overall survival (OS) of the three groups were compared. RESULTS: OS of TACE (vs. SC) was significantly longer (9.9 [5.9, 24.1] months versus 2.8 [1.5, 10.2], p = 0.001). Complete response of TEA was significantly better (TEA 10/19 [52.6%] versus TARE 2/17 [12.5%], p = 0.013, versus TACE 9/54 [16.7%], p = 0.002). OS of TEA (vs. TACE) was significantly longer (21.6 [12, 41] months versus 9.9 [5.9, 24.1], p = 0.014, hazard ratio 0.6 (0.3, 1). OS of TEA (vs. TARE) was longer (21.6 [12, 41] months versus 11.9 [7, 28.7], p = 0.082, hazard ratio 0.6 (0.3, 1.3) in favour of TEA). CONCLUSION: In patients with huge HCC, transarterial treatment as represented by TACE had a survival benefit over supportive care. In this retrospective analysis, TEA was associated with better tumour response and survival outcome as compared to TACE or TARE; therefore, transarterial treatment could be useful for prolonging patient survival, and TEA could be a preferred option.