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Monitoring interannual dynamics of desertification in Minqin County,China,using dense Landsat time series

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International Journal of Digital Earth 2020年第8期13卷 886-898页

作者： Xiaolin Zhu Kwok Huen leung Wing sze Li Lek Kin cheung The Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China The Hong Kong Polytechnic University Shenzhen Research Institute ShenzhenPeople’s Republic of China

Minqin County in northwestern China is highly affected by *** have been initiated in recent decades to combat desertification in *** assess the effectiveness of these campaigns,this study used a dense Landsat time series from 1987 to 2017 to investigate the interannual dynamics of vegetation coverage and greenness over the past 31 ***,this study applied an advanced technology to reconstruct a high-quality Landsat annual time ***,one image in the vegetation-peak season was selected as the base image in each year,and then problematic pixels were interpolated by the neighborhood similar pixel interpolator using ancillary images in the same ***,the land cover map and the enhanced vegetation index(EVI)were derived from all reconstructed ***,the change of vegetation coverage and EVI values over the 31 years were *** results show that the total vegetation coverage and greenness increased during the 31 *** this change trend to other factors suggests that vegetation in Minqin County is highly affected by agriculture and groundwater supply rather than by *** mitigate desertification in a sustainable way,agriculture should be well managed to avoid overconsumption of natural resources such as underground water.

关键词： Minqin County desertification agriculture Landsat time series vegetation cover

A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn J.W.So Konstantin Feinberg Marina Manoraj Jenny cheung Jennifer Zhang Kaveh Mirmoeini JPaul Santerre Tessa Gordon Gregory HBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

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Gastrointestinal bleeding in patients on novel oral anticoagulants:Risk,prevention and management

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World Journal of Gastroenterology 2017年第11期23卷 1954-1963页

作者： Ka-Shing cheung Wai K leung Department of Medicine The University of Hong KongQueen Mary HospitalHong KongChina

Novel oral anticoagulants(NOACs), which include direct thrombin inhibitor(dabigatran) and direct factor Xa inhibitors(rivaroxaban, apixaban and edoxaban), are gaining popularity in the prevention of embolic stroke in non-valvular atrial fibrillation as well as in the prevention and treatment of venous thromboembolism. However, similar to traditional anticoagulants, NOACs have the side effects of bleeding, including gastrointestinal bleeding(GIB). Results from both randomized clinical trials and observations studies suggest that high-dose dabigatran(150 mg b.i.d), rivaroxaban and high-dose edoxaban(60 mg daily) are associated with a higher risk of GIB compared with warfarin. Other risk factors of NOAC-related GIB include concomitant use of ulcerogenic agents, older age, renal impairment, Helicobacter pylori infection and a past history of GIB. Prevention of NOAC-related GIB includes proper patient selection, using a lower dose of certain NOACs and in patients with renal impairment, correction of modifiable risk factors, and prescription of gastroprotective agents. Overt GIB can be managed by withholding NOACs followed by delayed endoscopic treatment. In severe bleeding, additional measures include administration of activated charcoal, use of specific reversal agents such as idarucizumab for dabigatran and andexanent alfa for factor Xa inhibitors, and urgent endoscopic management.

关键词： Warfarin Endoscopy Apixaban Edoxaban Gastrointestinal bleeding Dabigatran Rivaroxaban Novel anticoagulants

X-reality for phantom limb management for amputees:A systematic review and meta-analysis

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Engineered Regeneration 2023年第2期4卷 134-151页

作者： James Chung-Wai cheung Daphne sze Ki cheung Ming Ni Kam-Wai Chen Ye-Jiao Mao Lin Feng Wing-Kai Lam Duo Wai-Chi Wong Aaron Kam-Lun leung Department of Biomedical Engineering Faculty of EngineeringThe Hong Kong Polytechnic UniversityHong KongChina School of Nursing The Hong Kong Polytechnic UniversityHong KongChina Department of Orthopaedics Ruijin HospitalShanghai Jiao Tong UniversityShanghaiChina Department of Prosthetics and Orthotics Queen Mary HospitalHong KongChina Sports Information and External Affairs Centre Hong Kong Sports InstituteHong KongChina Research Institute for Sports Science and Technology The Hong Kong Polytechnic UniversityHong KongChina Department of Rehabilitation Science The Hong Kong Polytechnic UniversityHong KongChina

Phantom limb is a disabling neuropsychiatric condition among amputees resulting in pain and disturbance that impact their functions,quality of life,and *** pharmacological approaches appeared to be ineffec-tive,the emergence and integration of X-reality,including virtual reality,augmented reality,and mixed reality,might elevate the effectiveness of mirror therapy in managing phantom *** objective of this study is to review X-reality for managing phantom pain.A systematic search was conducted on PubMed,Scopus,Web of Science,PsycINFO,Embase,and ***(n=16)studies containing 66 lower-limb and 53 upper-limb amputees were included for the review over the thematic framework of amputee characteristics and intervention designs,while thirteen(n=13)studies were further proceeded for the *** found eleven studies on virtual reality(n=11),four studies on marker-based augmented reality(n=4)and one study on mixed reality(n=1)with a total of 40 game/task themes involving,motor skills,motor control,and ***,all these interventions adopted the movement representation strategies with different ***,the X-reality interventions reduced the pain level of the amputees(mean difference:-2.30,95%CI,-3.38 to-1.22),especially the virtual reality subgroup(mean difference:-2.83,95%CI,-4.43 to-1.22).However,there were substantial heterogeneity and partially explained by the subgroup analysis on publication *** strength of evidence was limited by case reports and case series in this review.

关键词： Extended reality Limb telescoping Phantom pain Phantom sensation

Risk of gastric cancer development after eradication of Helicobacter pylori

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World Journal of Gastrointestinal Oncology 2018年第5期10卷 115-123页

作者： Ka-Shing cheung Wai K leung Department of Medicine The University of Hong Kong Queen Mary Hospital

Helicobacter pylori(H. pylori) infection is the most important risk factor for gastric cancer(gc) development through the correa's gastric carcinogenesis cascade. However, H. pylori eradication alone does not eliminate gc, as pre-neoplastic lesions(atrophic gastritis, intestinal metaplasia and dysplasia) may have already developed in some patients. It is therefore necessary to identify patients at high-risk for gastric cancer after H. pylori eradication to streamline the management plan. If the patients have not undergone endoscopy with histologic assessment, the identification of certain clinical risk factors and non-invasive testing(serum pepsinogen) can predict the risk of atrophic gastritis. For those with suspected atrophic gastritis, further risk stratification by endoscopy with histologic assessment according to validated histologic staging systems would be advisable. Patients with higher stages may require long-term endoscopic surveillance. Apart from secondary prevention to reduce deaths by diagnosing gc at an early stage, identifying medications that could potentially modify the gc risk would be desirable. The potential roles of a number of medications have been suggested by various studies, including proton pump inhibitors(PPIs), aspirin, statins and metformin. However, there are currently no randomized clinical trials to address the impact of these medications on gc risk after H. pylori eradication. In addition, most of these studies failed to adjust for the effect of concurrent medications on gc risk. Recently, large population-based retrospective cohort studies have shown that PPIs were associated with an increased gc risk after H. pylori eradication, while aspirin was associated with a lower risk. The roles of other agents in reducing gc risk after H. pylori eradication remain to be determined.

关键词： Gastric adenocarcinoma Stomach cancer Helicobacter pylori Chemoprevention Intestinal metaplasia

Application of Big Data analysis in gastrointestinal research

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World Journal of Gastroenterology 2019年第24期25卷 2990-3008页

作者： Ka-Shing cheung Wai K leung Wai-Kay Seto Department of Medicine The University of Hong KongQueen Mary HospitalHong KongChina Department of Medicine The University of Hong Kong- Shenzhen HospitalShenzhen 518053Guangdong ProvinceChina

Big Data,which are characterized by certain unique traits like volume,velocity and value,have revolutionized the research of multiple fields including *** Data in health care are defined as large datasets that are collected routinely or automatically,and stored *** the rapidly expanding volume of health data collection,it is envisioned that the Big Data approach can improve not only individual health,but also the performance of health care *** application of Big Data analysis in the field of gastroenterology and hepatology research has also opened new research *** it retains most of the advantages and avoids some of the disadvantages of traditional observational studies(case-control and prospective cohort studies),it allows for phenomapping of disease heterogeneity,enhancement of drug safety,as well as development of precision medicine,prediction models and personalized *** randomized controlled trials,it reflects the real-world situation and studies patients who are often under-represented in randomized controlled ***,residual and/or unmeasured confounding remains a major concern,which requires meticulous study design and various statistical adjustment *** potential drawbacks include data validity,missing data,incomplete data capture due to the unavailability of diagnosis codes for certain clinical situations,and individual *** continuous technological advances,some of the current limitations with Big Data may be further *** review will illustrate the use of Big Data research on gastrointestinal and liver diseases using recently published examples.

关键词： Healthcare dataset Epidemiology Gastric cancer Inflammatory bowel disease Colorectal cancer Hepatocellular carcinoma Gastrointestinal bleeding

Dual ultra-wideband(UWB)radar-based sleep posture recognition system:Towards ubiquitous sleep monitoring

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Engineered Regeneration 2023年第1期4卷 36-43页

作者： Derek Ka-Hei Lai Li-Wen Zha Tommy Yau-Nam leung Andy Yiu-Chau Tam Bryan Pak-Hei So Hyo-Jung Lim Daphne sze Ki cheung Duo Wai-Chi Wong James Chung-Wai cheung Department of Biomedical Engineering Faculty of EngineeringThe Hong Kong Polytechnic UniversityHong Kong 999077China Department of Bioengineering Imperial CollegeLondon SW72AZUnited Kingdom Research Institute of Smart Ageing The Hong Kong Polytechnic UniversityHong KongChina School of Nursing The Hong Kong Polytechnic UniversityHong KongChina

Sleep posture monitoring is an essential assessment for obstructive sleep apnea(OSA)*** objective of this study is to develop a machine learning-based sleep posture recognition system using a dual ultra-wideband radar *** collected radiofrequency data from two radars positioned over and at the side of the bed for 16 patients performing four sleep postures(supine,left and right lateral,and prone).We proposed and evaluated deep learning approaches that streamlined feature extraction and classification,and the traditional machine learning approaches that involved different combinations of feature extractors and *** results showed that the dual radar system performed better than either single *** statistical features with random forest classifier yielded the best accuracy(0.887),which could be further improved via an ablation study(0.938).Deep learning approach using transformer yielded accuracy of 0.713.

关键词： Obstructive sleep apnea Deep learning Sleep monitoring Feature extraction Ablation study

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Advances in Atmospheric Sciences 2022年第1期39卷 67-79页

作者： Paxson K.Y.cheung Wen ZHOU Dongxiao WANG Marco Y.T.leung Guy-Carpenter Asia-Pacific Climate Impact Centre School of Energy and EnvironmentCity University of Hong KongHong KongChina Department of Atmospheric and Oceanic Sciences&Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China School of Marine Sciences Sun Yat-sen UniversityGuangdong 510275China

This study focuses on the temporal variation of dissimilarity in heat content(HC)anomalies in the upper 300 m of ocean(HC300A)in the equatorial Pacific(±10°N)and its response to the El Ni?o-Southern Oscillation(ENSO).The HC300A anomalies are derived from four ocean reanalyses that are commonly used in ENSO studies and are compared using a simple differencing *** dissimilarity in HC300A is found to vary closely with the magnitude of ENSO(regardless of phase),meaning that it tends to be greater during strong ENSO ***,the dissimilarity among ocean reanalyses persists after the event *** effect is more pronounced after strong *** persistence of the dissimilarity after ENSO events is a result of a late maturation of the ENSO signal,its persistence,and the interruption of the signal decay due to follow-up ENSO *** combined effect of these three factors slows down the decay of HC300A in the region and hence results in the slow decay of *** is also found that areas with a significant spread in vertical temperature profiles collocate with the ENSO signal during warm ENSO ***,differences in subsurface process reconstruction are a significant factor in the dissimilarity among ocean reanalyses during warm ENSO events.

关键词： ocean reanalysis ocean heat content intercomparison ENSO equatorial Pacific

维普期刊数据库

LOCALLY NONLINEAR STOCHASTIC ANALYSIS OF OFFSHORE STRUCTURES

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China Ocean Engineering 1988年第3期2卷 1-10页

作者： Y.T.leung Y.K.cheung Department of Civil Engineering University of Hong Kong Hong Kong Professor Hong Kong Senior Lecturer

This paper’ presents a simple method for the stochastic dynamic analysis of some offshore platforms with localized nonlinearity. The transfer function of the platform with initial linear stiffness is first determined, and the nonlinear iteration is performed on the condensed stiffness matrix only. Computational efforts are reduced. This method can be used to analyze a fixed platform on nonlinear foundation and a guyed tower platform having nonlinear guylines.

关键词： LOCALLY NONLINEAR STOCHASTIC ANALYSIS OF OFFSHORE STRUCTURES