Publications by authors named "Clement Chan"

Background: Middle-aged adults, defined as individuals between the ages of 45 and 64, represent a significant yet under researched group of healthcare service users. This scoping review aimed to provide a comprehensive overview of the patterns of healthcare utilisation and the factors contributing to them within this demographic.

Methods: Following PRISMA-ScR guidelines and the framework proposed by Arksey and O'Malley, a systematic literature search was conducted across PubMed, EMBASE, and the Cochrane Library databases from their inception until July 2023.

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Background: Alzheimer's disease (AD), the most prevalent form of dementia, is a leading neurodegenerative disorder currently affecting approximately 55 million individuals globally, a number projected to escalate to 139 million by 2050. Despite extensive research spanning several decades, the cure for AD remains at a developing stage. The only existing therapeutic options are limited to symptom management, and are often accompanied by adverse side effects.

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Coastal cities face significant challenges from plastic pollution, with most plastics being resistant to biodegradation. Biodegradable plastics are increasingly used to address this issue, particularly for items prone to entering, and then accumulating, in waterways, through littering or leakage. Among biodegradable plastics, polyhydroxyalkanoates (PHAs) are notable as bioderived, bacterially synthesised aliphatic polyesters that are readily biodegradable in varied environments.

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The creation of complex cellular environments is critical to mimicking tissue environments that will play a critical role in next-generation tissue engineering, stem cell programming, and therapeutic screening. To address this growing need, techniques capable of manipulating cell-cell and cell-material interactions are required that span single-cell to 3D tissue architectures. DNA programmed assembly and placement of cells present a powerful technique for the bottom-up synthesis of living microtissues for probing key questions in cell-cell and cell-material-driven behaviors through its refined control over placement and architecture.

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Statistical analyses of homologous protein sequences can identify amino acid residue positions that co-evolve to generate family members with different properties. Based on the hypothesis that the coevolution of residue positions is necessary for maintaining protein structure, coevolutionary traits revealed by statistical models provide insight into residue-residue interactions that are important for understanding protein mechanisms at the molecular level. With the rapid expansion of genome sequencing databases that facilitate statistical analyses, this sequence-based approach has been used to study a broad range of protein families.

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An 85-year-old Chinese lady presented with a 5-day history of a painless left breast lump. There was no fever, nipple discharge, or history of trauma. She had a past medical history of atrial fibrillation that was managed with an oral anticoagulant.

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The persistence of conventional fossil fuel-derived plastics in marine ecosystems has raised significant environmental concerns. Biodegradable plastics are being explored as an alternative. This study investigates the biodegradation behaviour in two marine environments of melt-extruded sheets of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastic as well as blends of PHBV with a non-toxic plasticiser (triethyl citrate, TEC) and composites of PHBV with wood flour.

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Transcriptional regulators generate connections between biological signals and genetic outputs. They are used robustly for sensing input signals in building genetic circuits. However, each regulator can only generate a fixed connection, which generates constraints in linking multiple signals for more complex processes.

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The uridine diphosphate glycosyltransferase (UGT) superfamily plays a key role in the metabolism of xenobiotics and metabolic wastes, which is essential for detoxifying those species. Over the last several decades, a huge effort has been put into studying human and mammalian UGT homologs, but family members in other organisms have been explored much less. Potentially, other UGT homologs can have desirable substrate specificity and biological activities that can be harnessed for detoxification in various medical settings.

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Article Synopsis
  • UDP-glycosyltransferases (UGTs) are diverse enzymes involved in detoxifying various compounds, but many have not been fully studied for their potential uses.
  • A new fluorescent assay was developed to screen substrates of the plant UGT homolog, UGT71G1, which successfully identified 34 potential substrates among 159 tested compounds.
  • Confirmatory tests revealed that UGT71G1 can glycosylate toxic substances like bisphenol A and SN-38, highlighting the enzyme's promising role in environmental and medical applications.
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Polyhydroxyalkanoates (PHAs) are a group of natural polyesters that are synthesised by microorganisms. In general, their thermoplasticity and (in some forms) their elasticity makes them attractive alternatives to petrochemical-derived polymers. However, the high crystallinity of some PHAs - such as poly(3-hydroxybutyrate) (P3HB) - results in brittleness and a narrow processing window for applications such as packaging.

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Purpose: To report long-term results from a phase 1/2a clinical trial assessment of a scaffold-based human embryonic stem cell-derived retinal pigmented epithelium (RPE) implant in patients with advanced geographic atrophy (GA).

Design: A single-arm, open-label phase 1/2a clinical trial approved by the United States Food and Drug Administration.

Participants: Patients were 69-85 years of age at the time of enrollment and were legally blind in the treated eye (best-corrected visual acuity [BCVA], ≤ 20/200) as a result of GA involving the fovea.

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Purpose: The purpose of this study was to determine the impact of prophylactic ranibizumab (PR) injections given every 3 months in eyes with intermediate nonexudative age-related macular degeneration (AMD) on drusen volume, macular layer thicknesses, and progression of geographic atrophy (GA) area over 24 months in the PREVENT trial.

Methods: This post hoc analysis of the prospective PREVENT trial compared eyes with intermediate AMD randomized to PR versus sham injections to determine rates of conversion to neovascular AMD over 24 months. Drusen area and volume, macular thickness and volume, and retinal layer thicknesses were measured on spectral-domain optical coherence tomography images and analyzed.

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Bacterially derived polyhydroxyalkanoates (PHAs) are attractive alternatives to commodity petroleum-derived plastics. The most common forms of the short chain length (scl-) PHAs, including poly(3-hydroxybutyrate) (P3HB) and poly(3-hydroxybutyrate--3-hydroxyvalerate) (PHBV), are currently limited in application because they are relatively stiff and brittle. The synthesis of PHA--PHA block copolymers could enhance the physical properties of PHAs.

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While new biodegradable materials are being rapidly introduced to address plastic pollution, their end-of-life impacts remain unclear. Biodegradable plastics typically comprise a biopolymer matrix with functional additives and/or solid fillers, which may be toxic. Here, using an established method for continuous biodegradation monitoring, we investigated the impact of a commonly used plasticizer, dibutyl phthalate (DBP), on the biodegradation of poly(3-hydroxybutyrate--3-hydroxyvalerate) (PHBV) in soil.

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Iron is an essential element for various lifeforms but is largely insoluble due to the oxygenation of Earth's atmosphere and oceans during the Proterozoic era. Metazoans evolved iron transport glycoproteins, like transferrin (Tf) and lactoferrin (Lf), to keep iron in a non-toxic, usable form, while maintaining a low free iron concentration in the body that is unable to sustain bacterial growth. To survive on the mucosal surfaces of the human respiratory tract where it exclusively resides, the Gram-negative bacterial pathogen Moraxella catarrhalis utilizes surface receptors for acquiring iron directly from human Tf and Lf.

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Paunch is a fibrous solid residue consisting of partially digested feed from the stomachs of processed cattle. It is the largest untapped solid waste stream from animals at meat processing plants, and potentially a valuable source of fibres for the production of sustainable and potentially higher-value natural biocomposite materials. Paunch was obtained from the waste effluent of a red meat processing plant, and the fibre characteristics of the as-obtained material were studied and benchmarked against wood flour and ground buffel grass, with a view to evaluating the potential of paunch as a fibre for polymer composites.

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Bioplastics are materials that are biobased and/or biodegradable, but not necessarily both. Concerns about environmental plastic pollution are constantly growing with increasing demand for substituting fossil-based plastics with those made using renewable resource feedstocks. For many conventional bioplastics to completely decompose/degrade, they require specific environmental conditions that are rarely met in natural ecosystems, leading to rapid formation of micro-bioplastics.

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Gut microbial β-glucuronidase (gmGUS) is involved in the disposition of many endogenous and exogenous compounds. Preclinical studies have shown that inhibiting gmGUS activity affects drug disposition, resulting in reduced toxicity in the gastrointestinal tract (GIT) and enhanced systemic efficacy. Additionally, manipulating gmGUS activity is expected to be effective in preventing/treating local or systemic diseases.

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Purpose: To determine whether prophylactic ranibizumab prevents the development of neovascular age-related macular degeneration (nAMD) in eyes with intermediate age-related macular degeneration (AMD) for patients with preexisting nAMD in their contralateral eye.

Design: Multicenter randomized clinical trial.

Participants: Adults aged 50 years and older with intermediate AMD (multiple intermediate drusen [≥63 μm and <125 μm] or ≥1 large drusen [≥125 μm] and pigmentary changes) in the study eye and nAMD in the contralateral eye.

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Article Synopsis
  • * Postmortem analysis of one patient shows that the implanted donor RPE cells survived for two years and demonstrated functional characteristics, indicating they can integrate successfully into the host tissue.
  • * Despite the significant immune system mismatch between the donor and the host, no adverse immune reactions or inflammation were observed in any patients, suggesting the potential for successful cell-based therapies without the need for long-term immune suppression.
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