Publications by authors named "Ka M Ng"

This article presents a numerical platform for predicting the performance of paper-based analytical devices. The capillary flow, reaction, dissolution, and other physicochemical phenomena associated with device operation are accounted for using Darcy's law, Richard's equation and other transport equations. The platform can be used for different paper substrates, biorecognition methods, detection systems (such as optical and electrochemical detection), device patterns and dimensions, and ways in which the device is operated such as the input method of the body fluid.

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A novel calcium copper titanate (CaCuTiO)-polyvinylidene fluoride composite (CCTO@PVDF) with Cu-deficiency was successfully prepared through the molten salt-assisted method. The morphology and structure of polymer composites uniformly incorporated with CCTO nanocrystals were characterized. At the same volume fraction, the CCTOs with Cu-deficiency displayed higher dielectric constants than those without post-treatment.

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Background: Elderly-onset inflammatory bowel disease [IBD], defined as age ≥60 at diagnosis, is increasing worldwide. We aimed to compare clinical characteristics and natural history of elderly-onset IBD patients with those of adult-onset IBD patients.

Methods: Patients with a confirmed diagnosis of IBD from 1981 to 2016 were identified from a territory-wide Hong Kong IBD registry involving 13 hospitals.

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Role of 5-aminosalicylic acid (5-ASA), statin and aspirin in reducing cancer risks in inflammatory bowel disease (IBD) remains controversial. We aimed to examine chemo-preventive effects of these drugs in all cancers in IBD in population-based setting. IBD patients diagnosed between 2000 and 2016 were identified from the Hong Kong IBD Registry and followed from IBD diagnosis until first cancer occurrence.

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Galectin-3 is a vital biomarker for cancer progression. An aggregation-induced emission (AIE)-active nanoparticle probe is designed and synthesized for label-free detection of galectin-3 based on carbohydrate-protein interactions. The probe employs tetraphenylethene (TPE) as the fluorescent core structure and N-acetyllactosamine (LacNAc) as galactoside residues and self-aggregates into uniform nanoparticles with multiple binding sites on the surface targeting galectin-3.

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Background: Little is known of the outcome of patients with perianal Crohn's disease after stopping anti-tumour necrosis factor (TNF) therapy.

Aim: To evaluate the rate of relapse in perianal Crohn's disease (CD) after stopping anti-TNF therapy.

Methods: Consecutive perianal CD patients treated with anti-TNF therapy with subsequent discontinuation were retrieved from prospective inflammatory bowel disease database of institutes in Hong Kong, Shanghai, Taiwan, Malaysia, Thailand and Singapore from 1997 to June 2019.

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We report the thermoelectric performance of p-type nanocrystalline SnSe obtained from the liquid phase sintering of blends of SnSe nanocrystals and Te nanorods. A cycled hot press procedure at a temperature above the Te melting point promoted the formation of crystallographically textured SnSe nanomaterials with relative densities up to 93%. After consolidation, part of this Te was found within the SnSe lattice and part remained as elemental Te between the SnSe grains.

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In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe nanoplates (NPLs) and their use to produce crystallographically textured SnSe nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism.

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Hypoxanthine is a well-known indicator of intracellular energy status that is associated with many pathological conditions. We report a fluorescent luminogen (TPE-HPro) with aggregation-induced emission (AIE) feature which, along with xanthine oxidase (XO), detects and quantifies hypoxanthine in a "turn-on" manner. The superior detection performance of this fluorometric assay indicates its great potential for biomedical diagnostics.

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In the present work, we demonstrate crystallographically textured n-type BiTeSe nanomaterials with exceptional thermoelectric figures of merit produced by consolidating disk-shaped BiTeSe colloidal nanocrystals (NCs). Crystallographic texture was achieved by hot pressing the asymmetric NCs in the presence of an excess of tellurium. During the hot press, tellurium acted both as lubricant to facilitate the rotation of NCs lying close to normal to the pressure axis and as solvent to dissolve the NCs approximately aligned with the pressing direction, which afterward recrystallize with a preferential orientation.

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Bottom-up approaches for producing bulk nanomaterials have traditionally lacked control over the crystallographic alignment of nanograins. This limitation has prevented nanocrystal-based nanomaterials from achieving optimized performances in numerous applications. Here we demonstrate the production of nanostructured Bi SbTe alloys with controlled stoichiometry and crystallographic texture through proper selection of the starting building blocks and the adjustment of the nanocrystal-to-nanomaterial consolidation process.

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Iron sulfide embedded porous carbon hollow spheres (FeS@CS) have been successfully synthesized through a facile and environment friendly in situ synthetic method. Using this method, a porous carbon matrix and uniformly dispersed iron sulfide nanoparticles were formed simultaneously and assembled into hollow spheres. The as-synthesized FeS@CS material showed high reversible capacity, outstanding cycle performance, and excellent rate capability when it was applied as an anode material for sodium ion batteries.

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Silicon doped tin oxide embedded porous carbon microspheres (Si Sn O @C) are synthesized. It is found that the doped Si not only improves the reversibility of lithiation/delithiation reactions, but also prevents Sn from aggregation. In addition, the doped Si introduces extra defects into the carbon matrix and produces Li conductive Li SiO , which accelerates Li diffusion.

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Introduction: Appendectomy has long been the mainstay of intervention for acute appendicitis, aiming at preventing perforation, peritonitis, abscess formation and recurrence. With better understanding of the disease process, non-operative management (NOM) with antibiotics alone has been proved a feasible treatment for uncomplicated appendicitis. This article aimed at systematically reviewing the available literatures and discussing the question whether NOM should replace appendectomy as the standard first-line treatment for uncomplicated appendicitis.

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l-Lactate is a vital biomarker for many diseases and physiological fatigue. An AIE-active fluorophore (TPE-HPro) is combined with l-lactate oxidase (LOx) to determine l-lactate in aqueous fluid. The assay shows excellent sensitivity and anti-interference performance with a limit of detection (LOD) of 5.

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In this study, the capability of using aerobic granules to undergo simultaneous anaerobic decolorization and aerobic aromatic amines degradation was demonstrated for azo dye wastewater treatment. An integrated acclimation-granulation process was devised, with Mordant Orange 1 as the model pollutant. Performance tests were carried out in a batch column reactor to evaluate the effect of various operating parameters.

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1-[4-(Bromomethyl)phenyl]-1,2,2-triphenylethene (2) was synthesized and evaluated for specific fluorescent prestaining of proteins containing cysteine (Cys) in SDS-PAGE. The molecule showed classic aggregation-induced emission (AIE) property in protein labeling and its quantum efficiency was further enhanced upon reacting with Cys. The parameters of reaction such as labeling time and concentration of dye and reducing reagent-tris(2-carboxyethyl)phosphine (TCEP) were examined to obtain the optimal labeling condition.

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Background: Both gastric and colorectal cancers (CRC) are the most frequently occurring malignancies worldwide with the overall survival of these patients remains unsatisfied. Identification of tumor suppressor genes (TSG) silenced by promoter CpG methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic biomarkers for early cancer detection and prognosis assessment. Cystathionine-beta-synthase (CBS) functions in the folate metabolism pathway, which is intricately linked to methylation of genomic DNA.

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A new aggregation-induced emission (AIE) compound 1,2-bis[4-(isothiocyanatomethyl)phenyl]-1,2-diphenylethene (2) was synthesized for use in SDS-PAGE. The molecule is practically nonemissive in solution but becomes highly emissive after reacting with the amine groups of the proteins by either the prestaining or poststaining method. The sensitivity of 2 achieved in the prestaining method is the same as that of Coomassie brilliant blue (CBB), while that observed in the poststaining method is higher than that of CBB.

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Epigenetic disruption of tumor suppressor genes is frequently involved in tumorigenesis. We identified a novel 19q13 KRAB domain-containing zinc finger protein, ZNF545/ZFP82, broadly expressed in normal tissues but downregulated in multiple tumor cell lines. The ZNF545 promoter contains a CpG island, which is frequently methylated in cell lines.

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A new aggregation-induced emission (AIE) compound 1,1-dimethyl-2,5-bis[4-(isothiocyanatemethyl)phenyl]-3,4-diphenylsilole (SITC) was synthesized and used to conjugate with aminoallyl-dUTP. The SITC-dUTP can be incorporated enzymatically into DNA strands with the degree of labeling (DOL) up to the theoretic limit.

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The malignant Hodgkin/Reed-Sternberg (HRS) cells of Hodgkin lymphoma (HL) are believed to derive from germinal center (GC) B cells, but lack expression of a functional B cell receptor. As apoptosis is the normal fate of B-cell receptor-negative GC B cells, mechanisms that abrogate apoptosis are thus critical in HL development, such as epigenetic disruption of certain pro-apoptotic cancer genes including tumor suppressor genes. Identifying methylated genes elucidates oncogenic mechanisms and provides valuable biomarkers; therefore, we performed a chemical epigenetic screening for methylated genes in HL through pharmacological demethylation and expression profiling.

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Purpose: Identifying tumor suppressor genes silenced by promoter CpG methylation uncovers mechanisms of tumorigenesis and identifies new epigenetic biomarkers for early cancer detection. DLEC1 is located at 3p22.3, a critical tumor suppressor gene locus for renal cell carcinoma.

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