Storm surge and waves associated with tropical cyclones carry significant amounts of pollutants into the marine environment. This study evaluated the effects of Typhoon Mangkhut (7–18 September 2018) ...on marine debris pollution including macro-debris (>2.5 cm) and microplastics (5 μm–5 mm) in Hong Kong. Sampling was repeated on four beaches, two each from protected and exposed coastal areas, spanning from the eastern to western waters before and after the cyclone. For macro-debris, an average density of 0.047 items m−2 and 0.54 items m−2 was obtained before and after the cyclone, respectively or an 11.4-fold increase, with plastic being the most dominant type (61.9–93.3% and 80.7–92.4% before and after the cyclone, respectively) among total beached debris in all four beaches. Likewise, higher mean microplastic abundances were found in the post-cyclone period (335 items kg−1 sediment) when compared with the pre-cyclone period (188 items kg−1 sediment). The depositional dynamics for both macro-debris and microplastic were site-specific due to factors such as wind direction and the associated storm surge, topography and orientation of the site, and proximity to urban areas. This study has demonstrated the role cyclone induced overwash plays on introducing plastic pollution to beach environments. Considering an increase in both the intensity and frequency of cyclone in the future due to global warming, and a tremendous increase in marine plastic debris, more research effort should be spent on this understudied problem.
Display omitted
•The pollution level of marine debris was compared before and after cyclone.•Abundance of macro-debris and microplastics increased tremendously after cyclone.•Pollution level was determined by site-specific factors.•Plastic was the most frequently found material among all the debris.•Chemical compositions of microplastics became more diverse after cyclone.
The visual survey is the most common method to quantify and characterize beach litter. However, it is very labor intensive and difficult to carry out on beaches which are remote or difficult to ...access. We suggest an alternative approach for assessing beach litter using an unmanned aerial vehicle (UAV), or aerial drone, with automated image requisition and processing. Litter of different sizes, colours, and materials were placed randomly on two beaches. Images of beaches with different substrates were obtained by the drone at different operating heights and light conditions and litter on the beaches was identified from the photos by untrained personnel. The quantification of beach litter using the drone was three times faster than that by visual census. This study has demonstrated the potential of using the drone as a cost-effective and an efficient sampling method in routine beach litter monitoring programs.
Research on plastics fragmentation is important for the estimation of amount of microplastics but the biological causes for fragmentation have not been acknowledged. From microplastics collected in ...the beaches of Hong Kong, we revealed an abnormal type of fragment which has not been reported before. These fragments, composing about 6% of the microplastics (pellet, foam, bead, fragment) collected, were interestingly triangular in shape with at least two of the three sides being characteristically straight and resembling a cut made by compression. Objective observations have distinguished these “trimmed triangular fragments” to those triangular fragments that were fractured randomly. By comparing with additional evidence, we proposed that these trimmed fragments were the daughter pieces of macrofaunal biting. If this was so, there would be wide implications on fragmentation modeling studies for microplastics since active biting of large plastic debris has generally not been considered as a factor of plastics fragmentation.
Display omitted
Absorption spectroscopy is commonly utilized to probe optical properties that can be related, among other things, to the conformation of single, isolated conjugated polymer chains in solution. It is ...frequently suggested that changes in peak positions of optical spectra result from variations in the stiffness of polymer chains in solution because this modifies the conjugation length. In this work we utilize ultraviolet–visible (UV–vis) spectroscopy, small angle neutron scattering (SANS), and all atom molecular dynamic (AA-MD) simulations to closely probe the relationship between the conformation of single-chains of poly(3-alkylthiophene)s (P3ATs) and their optical properties. SANS results show variations in the radius of gyration and Kuhn length as a function of alkyl chain length, and structure, as well as the solvent environment. Furthermore, both SANS and MD simulations show that dissolved P3HT chains are more rigid in solvents where self-assembly and crystallization are possible. Shifts in P3AT optical properties were also observed for different solvent environments. However, these changes were not correlated to the changes in polymer conformation. Furthermore, changes in optical properties could not be perfectly described by generalized solvent–solute interactions. AA-MD simulations provide new insights into specific polymer–solvent interactions not accounted for in generalized solvatochromic theory. This work highlights the need for experiments and molecular simulations that further inform the specific role of solvent molecules on local polymer conformation and on optical properties.
KLHL40-related nemaline myopathy is a severe autosomal recessive muscle disorder. The current study describes 4 cases of KLHL40-related nemaline myopathy in Hong Kong ethnic Chinese presenting within ...3 years, which are confirmed with clinicopathologic features and genetic studies. The incidence is estimated to be at least 1 in 45 226 livebirths (at least 1 in 41 608 among ethnic Chinese livebirths) in Hong Kong. Hyponatremia appears to be another common feature in these patients. Salient histological features include nemaline bodies ranging from 200 to 500 nm in diameters on ultrastructural examination as well as negative KLHL40 immunohistochemistry; type II fiber predominance is obvious in 2 cases. We demonstrate the founder effect associated with genetic variant c.1516A>C (p.Thr506Pro) by polymorphic marker analysis, which revealed a 0.56-0.75-Mb or 0.41-0.78-cM shared haplotype encompassing the disease allele. The mutation is believed to have occurred around 412 generations ago or 6220 BCE, as estimated using DMLE+ and a formula described by Boehnke. We believe the founder variant might possibly underlie a sizable portion of nemaline myopathy in ethnic Chinese. Analysis of the KLHL40 gene may be considered as the first-tier testing of congenital myopathy in this ethnic group.
Long COVID has been reported among patients with COVID‐19, but little is known about the prevalence and risk factors associated with long COVID 6–12 months after infection with the Omicron variant. ...This is a large‐scale retrospective study. A total of 6242 out of 12 950 nonhospitalized subjects of all ages with SARS‐CoV‐2 infection (confirmed by polymerase chain reaction/rapid antigen test) during the Omicron dominant outbreak (December 31, 2021–May 6, 2022) in Hong Kong were included. Prevalence of long COVID, frequencies of symptoms, and risk factors were analyzed. Three thousand four hundred and thirty (55.0%) subjects reported at least one long COVID symptom. The most reported symptom was fatigue (1241, 36.2%). Female gender, middle age, obesity, comorbidities, vaccination after infection, having more symptoms, and presenting fatigue/chest tightness/headache/diarrhea in the acute stage of illness were identified as associated risk factors for long COVID. Patients who had received three or more doses of vaccine were not associated with a lower risk of long COVID (adjusted odds ratio 1.105, 95% confidence interval 0.985–1.239, p = 0.088). Among patients with at least three doses of vaccine, there was no significant difference in the risk of long COVID between the CoronaVac vaccine and BNT162b2 vaccine (p > 0.05). Omicron infection can lead to long COVID in a significant proportion of nonhospitalized patients 6–12 months after infection. Further investigation is needed to uncover the mechanisms underlying the development of long COVID and determine the impact of various risk factors such as vaccines.
Abstract An injectable tissue-engineered adipose substitute that could be used to deliver adipose-derived stem cells (ASCs), filling irregular defects and stimulating natural soft tissue ...regeneration, would have significant value in plastic and reconstructive surgery. With this focus, the primary aim of the current study was to characterize the response of human ASCs encapsulated within three-dimensional bioscaffolds incorporating decellularized adipose tissue (DAT) as a bioactive matrix within photo-cross-linkable methacrylated glycol chitosan (MGC) or methacrylated chondroitin sulphate (MCS) delivery vehicles. Stable MGC- and MCS-based composite scaffolds were fabricated containing up to 5 wt% cryomilled DAT through initiation with long-wavelength ultraviolet light. The encapsulation strategy allows for tuning of the 3-D microenvironment and provides an effective method of cell delivery with high seeding efficiency and uniformity, which could be adapted as a minimally-invasive in situ approach. Through in vitro cell culture studies, human ASCs were assessed over 14 days in terms of viability, glycerol-3-phosphate dehydrogenase (GPDH) enzyme activity, adipogenic gene expression and intracellular lipid accumulation. In all of the composites, the DAT functioned as a cell-supportive matrix that enhanced ASC viability, retention and adipogenesis within the gels. The choice of hydrogel also influenced the cell response, with significantly higher viability and adipogenic differentiation observed in the MCS composites containing 5 wt% DAT. In vivo analysis in a subcutaneous Wistar rat model at 1, 4 and 12 weeks showed superior implant integration and adipogenesis in the MCS-based composites, with allogenic ASCs promoting cell infiltration, angiogenesis and ultimately, fat formation.
Omicron BA.2.2 is the dominant variant in the Hong Kong outbreak since December 31, 2021. There is no study reporting the weekly symptom profile after infection. In this retrospective study, ...participants who tested positive for SARS‐CoV‐2 after December 31, 2021, and registered in the telemedicine system between March 14 and May 6, 2022, were analyzed. Among registered 12 950 self‐quarantined COVID‐19‐positive patients, 11 776 symptomatic patients were included for weekly symptom profile analysis. A total of 4718 (40.1%) patients reported symptoms in the first week after a positive test, 2501 (21.2%) in the second week, 1498 (12.7%) in the third week, 1048 (8.9%) in the fourth week, and 2011 (17.1%) in over 4 weeks. Cough was the most common symptom in all participants. Patients in the first week had higher odds of reporting fever (0.206, 95% confidence interval CI: 0.161–0.263, p < 0.001) and sore throat (0.228, 95% CI: 0.208–0.252, p < 0.001). Patients in over 4 weeks had higher odds of reporting fatigue (1.263, 95% CI: 1.139–1.402, p < 0.001). Further, having at least two vaccine doses linked to lower odds of having fever (0.675, 95% CI: 0.562–0.811, p < 0.001), but not associated with the presence of cough and fatigue. Diabetic patients had higher odds of reporting diarrhea (1.637, 95% CI: 1.351–1.982, p < 0.001). Symptoms from Omicron infection may last for more than 4 weeks and symptom profiles vary from week to week. Vaccination and comorbidity affect the symptom profiles.
The occurrence and spatial distribution of bisphenol A (BPA) and analogues bisphenol B (BPB), bisphenol F (BPF) and bisphenol S (BPS) were investigated in microplastic on 11 beaches in Hong Kong. At ...10 sites, BPA was the only detected chemical with concentrations ranged from 82.4–989 ng g−1 microplastic. BPA, BPB and BPS co-occurred at only one site, where it is located close proximity to the outfall of a sewage treatment plant. There was no significant spatial difference of BPA concentrations in microplastic when all the sites were considered, indicating that some remote and presumably cleaner beaches have been contaminated. PE, PP and PS (represented >90% of total polymers) were the most dominated polymers, but there was no correlation between polymer types and BPA concentrations. No evidence was found that the BPA and its analogues accumulate on microplastic since the concentrations were comparable to those found in the sediment.
•BPA was present in all microplastic samples collected on 11 Hong Kong beaches.•BPB and BPS were only present at one site near a sewage treatment plant.•No spatial difference was found, indicating potential impact at remote sites.•No correlation was found between polymer types and BPA concentrations.
A composite bioscaffold was constructed by encapsulating human decellularized adipose tissue (DAT) within a photopolymerized polysaccharide hydrogel towards the goal of forming an injectable scaffold ...for adipose tissue engineering. Methacrylated glycol chitosan (MGC) and methacrylated chondroitin sulphate (MCS) were investigated as the hydrogel base materials with varying DAT concentrations. Glycol chitosan and chondroitin sulphate were converted to photopolymerizable prepolymers through graft methacrylation using glycidyl methacrylate and methacrylate anhydride respectively to achieve a degree of substitution (DOS) of 15% and 16%, respectively. MGC and MCS gels containing 0, 3 and 5 w/v% cryo-milled DAT were fabricated and characterized by measuring sol content, equilibrium water content and compressive mechanical properties (n=4, n=3). An increase in stiffness and a decrease in sol and water contents were observed in the gels with higher DAT concentration, suggesting that the DAT was acting as a filler material that contributed to the crosslinking reaction. In vitro studies were conducted with primary human adipose-derived stem cells (ASCs) encapsulated in the DAT-polymer constructs to assess cellular viability (n=3, N=3) as well as adipogenic differentiation, quantitatively via glycerol-3-phosphate dehydrogenase (GPDH) enzyme activity (n=3, N=3) and qualitatively through end-point RT-PCR analysis of key adipogenic genes (LPL, PPARγ, and CEPBα) (n=2, N=3) and intracellular lipid staining (n=3, N=3). Incorporating the DAT with MGC or MCS hydrogels enhanced cell viability as compared to the MGC and MCS scaffolds alone, with the MCS + 5 w/v% DAT scaffold having the highest overall cell viability and total cell number. The addition of the DAT in the MGC and MCS scaffold groups enhanced ASC adipogenesis as measured by an increase in GPDH levels, adipogenic gene expression and intracellular lipid accumulation characteristic of adipocytes. The highest GPDH levels were observed in the induced MCS with 5 w/v% DAT scaffolds, as compared to all other scaffold groups and tissue culture controls. The GPDH activity in this group increased by almost three times between 3 and 14 days, consistent with the progression of differentiation. The results indicated that the MCS-based scaffolds incorporating the DAT promoted cell viability and adipogenesis, demonstrating great promise as composite scaffolds for soft tissue regeneration.
PDF
