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Xueyang Fang, Kwok-Ho Lui, Shiying Li, Wai-Sum Lo, Xin Li, Yanjuan Gu, Wing-tak Wong Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, People’s Republic of ChinaCorrespondence: Yanjuan Gu; Wing-tak WongDepartment of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, People’s Republic of ChinaTel +852 3400 8858; +852 3400 8789Fax +852 2364 9932Email yanjuan.gu@polyu.edu.hk; w.t.wong@polyu.edu.hkIntroduction: Cancer theragnosis involving cancer diagnosis and targeted therapy simultaneously in one integrated system would be a promising solution of cancer treatment. Herein, a convenient and practical cancer theragnosis agent was constructed by combining gold nanocages (AuNCs) covered with selenium and a chitosan (CS) shell (AuNCs/Se) to incorporate the anti-cancer drug doxorubicin (DOX) as a multifunctional targeting nanocomposite (AuNCs/DOX@Se-iRGD) for photoacoustic imaging (PAI)-guided chemo-photothermal synergistic therapy that contributes to enhanced anti-cancer efficacy. The novel design of AuNCs/DOX@Se-iRGD gives the nanocomposite two outstanding properties: (1) AuNCs, with excellent LSPR property in the NIR region, act as a contrast agent for enhanced PAI and photothermal therapy (PTT); (2) Se acts as an anti-cancer nanoagent and drug delivery cargo.Methods: The photothermal performance of these nanocomposites was evaluated in different concentrations with laser powder densities. These nanocomposites were also incubated in pH 5.3, 6.5, 7.4 PBS and NIR laser to study their drug release ability. The cellular uptake was studied by measuring the Se and Au concentrations inside the cells using inductively coupled plasma-mass spectrometry (ICP-MS). Besides, in vitro and in vivo anti-tumor activity were carried out by cytotoxicity assay MTT and tumor model nude mice, respectively. As for imaging, the PA value and images of these nanocomposites accumulated in the tumor site were sequentially collected at specific time points for 48 h.Results and Discussion: The prepared AuNCs/DOX@Se-iRGD showed excellent biocompatibility and physiological stability in different media. In vivo results indicated that the targeting nanocomposite presented the strongest contrast-enhanced PAI signals, which could provide contour and location information of tumor, 24 h after intravenous injection. Likewise, the combined treatment of chemo- and photothermal synergistic therapy significantly inhibited tumor growth when compared with the two treatments carried out separately and showed negligible acute toxicity to the major organs.Conclusion: This study demonstrates that AuNCs/DOX@Se-iRGD has great prospect to become a multifunctional anti-tumor nanosystem for PAI-guided chemo- and photothermal synergistic therapy.Keywords: gold nanocage, nanocomposites, NIR, PA imaging, synergistic therapy

Organocatalyzed ring-opening polymerization (ROP) is a versatile technique for synthesizing biodegradable polymers, including polyesters and polycarbonates. We introduce o -phenylene bisurea (OPBU) (di)anions as a novel class of organocatalysts that are fast, easily tunable, mildly basic, and exceptionally selective. These catalysts surpass previous generations, such as thiourea, urea, and TBD, in selectivity ( k p / k tr ) by 8 to 120 times. OPBU catalysts facilitate the ROP of various monomers, achieving high conversions (>95%) in seconds to minutes, producing polymers with precise molecular weights and very low dispersities ( Đ ≈ 1.01). This performance nearly matches the ideal distribution expected from living polymerization (Poisson distribution). Density functional theory (DFT) calculations reveal that the catalysts stabilize the oxyanion transition state via a hydrogen bond pocket similar to the "oxyanion hole" in enzymatic catalysis. Both experimental and theoretical analyses highlight the critical role of the semirigid o -phenylene linker in creating a hydrogen bond pocket that is tight yet flexible enough to accommodate the oxyanion transition state effectively. These new insights have provided a new class of organic catalysts whose accessibility, moderate basicity, excellent solubility, and unparalleled selectivity and tunability open up new opportunities for controlled polymer synthesis.

The heavy metals and bioreactivity properties of endotoxin in personal exposure to fine particulate matter (PM 2.5 ) were characterized in the analysis. The average personal exposure concentrations to PM 2.5 were ranged from 6.8 to 96.6 μg/m 3 . The mean personal PM 2.5 concentrations in spring, summer, autumn, and winter were 32.1±15.8, 22.4±11.8, 35.3±11.9, and 50.2±19.9 μg/m 3 , respectively. There were 85 % of study targets exceeded the World Health Organization (WHO) PM 2.5 threshold (24 hours). The mean endotoxin concentrations ranged from 1.086 ± 0.384-1.912 ± 0.419 EU/m 3 , with a geometric mean (GM) varied from 1.034 to 1.869. The concentration of iron (Fe) (0.008-1.16 μg/m 3 ) was one of the most abundant transition metals in the samples that could affect endotoxin toxicity under Toll-Like Receptor 4 (TLR4) stimulation. In summer, the interleukin 6 (IL-6) levels showed statistically significant differences compared to other seasons. Spearman correlation analysis showed endotoxin concentrations were positively correlated with chromium (Cr) and nickel (Ni), implying possible roles as nutrients and further transport via adhering to the surface of fine inorganic particles. Mixed-effects model analysis demonstrated that Tumor necrosis factor-α (TNF-α) production was positively associated with endotoxin concentration and Cr as a combined exposure factor. The Cr contained the highest combined effect (0.205-0.262), suggesting that Cr can potentially exacerbate the effect of endotoxin on inflammation and oxidative stress. The findings will be useful for practical policies for mitigating air pollution to protect the public health of the citizens., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Prof. Kin Fai HO reports financial support was provided by The Chinese University of Hong Kong. Prof. Kin Fai HO reports a relationship with The Chinese University of Hong Kong that includes: employment and funding grants. Not available. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This study investigated the determinants of personal exposures (PE) to coarse (PM 2.5-10 ) and fine particulate matter (PM 2.5 ) for elderly communities in Hong Kong. The mean PE PM 2.5 and PM 2.5-10 were 23.6 ± 10.8 and 13.5 ± 22.1 μg/m 3 , respectively during the sampling period. Approximately 76% of study subjects presented statistically significant differences between PE and ambient origin for PM 2.5 compared to approximately 56% for PM 2.5-10 , possibly due to the coarse-size particles being more influenced by similar sources (road dust and construction dust emissions) compared to the PM 2.5 particles. Individual PE to ambient (P/A) ratios for PM 2.5 all exceeded unity (≥1), suggesting the dominant influences of non-ambient particles contributed towards total PE values. There were about 80% individual P/A ratios (≤1) for PM 2.5-10 , implying possible effective infiltration prevention of larger size particulate matter particles leading to dominant influences from the outdoor sources. The higher concentration of NO 3 - and SO 4 2- in PM 2.5-10 compared to PM 2.5 suggests possible heterogeneous reactions of alkaline minerals leading to the formation of NO 3 - and SO 4 2- in PM 2.5-10 particles. The PE and ambient OC/EC ratios in PM 2.5 (8.8 ± 3.3 and 10.4 ± 22.4, respectively) and in PM 2.5-10 (6.0 ± 1.9 and 3.0 ± 1.1, respectively) suggest possible secondary formed OC from surrounding rural areas. Heterogeneous distributions (COD >0.2) between the PE and ambient concentrations were found for both the PM 2.5 and PM 2.5-10 samples. The calibration coefficient as the association between personal and surrogate exposure measure of PE to PM 2.5 (0.84) was higher than PM 2.5-10 (0.52). The findings further confirm that local sources were the dominant contributor to the coarse particles and these coefficients can potentially be used to estimate different PE to PM 2.5 and PM 2.5-10 conditions. A comprehensive understanding of the PE to determinants in coarse particles is essential to further reduce potential exposure misclassification., Competing Interests: Declaration of competing interest We have declared no financial interests/personal relationships which may be considered as potential competing interests Prof. Kin Fai HO reports financial support was provided by The Chinese University of Hong Kong. Prof. Kin Fai HO reports a relationship with The Chinese University of Hong Kong that includes: employment and funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Organocatalyzed ring-opening polymerization is a powerful tool for the synthesis of a variety of functional, readily degradable polyesters and polycarbonates. We report the use of (thio)ureas in combination with cyclopropenimine bases as a unique catalyst for the polymerization of cyclic esters and carbonates with a large span of reactivities. Methodologies of exceptionally effective and selective cocatalyst combinations were devised to produce polyesters and polycarbonates with narrow dispersities ( Đ = 1.01-1.10). Correlations of the p K a of the various ureas and cyclopropenimine bases revealed the critical importance of matching the p K a of the two cocatalysts to achieve the most efficient polymerization conditions. It was found that promoting strong H-bonding interactions with a noncompetitive organic solvent, such as CH 2 Cl 2 , enabled greatly increased polymerization rates. The stereoselective polymerization of rac -lactide afforded stereoblock poly(lactides) that crystallize as stereocomplexes, as confirmed by wide-angle X-ray scattering.

The chemical properties of fresh and aged aerosol emitted during controlled vehicular exhaust emissions were characterized in the analysis. Pyrene (10417.1 ± 534.9 ng kg -1 ) is the most abundant of all analyzed compounds in total fresh emission and succinic acid (57359.8 ± 4000.3 ng kg -1 ) is for the total aged emission. The fresh emission factors (EF fresh ) of all compounds in the n-alkanes group demonstrate higher average emissions for the two vehicles with EURO 3 standard compared to the other vehicles. The EF fresh for benzo [a]pyrene is in descending order: G1 (183.1 ± 144.7 ng kg -1 ) > G3 (103.4 ± 60.1 ng kg -1 ) > G4 (91.2 ± 80.1 ng kg -1 ) > G2 (88.6 ± 93.9 ng kg -1 ). Aged/fresh (A/F) emission ratios (>20) confirmed that these diacid compounds are generated by the photooxidation of primary pollutants that emitted from gasoline combustions. High A/F ratios (>200) in phthalic acid, isophthalic acid and terephthalic acid under idling mode imply relatively more intense photochemical reactions for their productions compared with other chemical groups. Strong positive correlations (r > 0.6) were observed between the degradation of toluene and formations of pinonic acid, succinic acid, adipic acid, terephthalic acid, glutaric acid and citramalic acid after the aging process, suggesting possible photooxidation of toluene that can lead to secondary organic aerosol (SOA) formation in the urban atmosphere. The findings demonstrate that vehicle emission standards for pollution in relation to the change of particulate matter chemical compositions and SOA formations. The results warrant a need for regulated reformulation for such vehicles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The 3' ends of eukaryotic mRNAs are generated by cleavage of nascent transcripts followed by polyadenylation, which occurs at numerous sites within 3' untranslated regions (3' UTRs) but rarely within coding regions. An individual gene can yield many 3'-mRNA isoforms with distinct half-lives. We dissect the relative contributions of protein-coding sequences (open reading frames [ORFs]) and 3' UTRs to polyadenylation profiles in yeast. ORF-deleted derivatives often display strongly decreased mRNA levels, indicating that ORFs contribute to overall mRNA stability. Poly(A) profiles, and hence relative isoform half-lives, of most (9 of 10) ORF-deleted derivatives are very similar to their wild-type counterparts. Similarly, in-frame insertion of a large protein-coding fragment between the ORF and 3' UTR has minimal effect on the poly(A) profile in all 15 cases tested. Last, reciprocal ORF/3'-UTR chimeric genes indicate that the poly(A) profile is determined by the 3' UTR. Thus, 3' UTRs are self-contained modular entities sufficient to determine poly(A) profiles and relative 3'-isoform half-lives. In the one atypical instance, ORF deletion causes an upstream shift of poly(A) sites, likely because juxtaposition of an unusually high AT-rich stretch directs polyadenylation closely downstream. This suggests that long AT-rich stretches, which are not encountered until after coding regions, are important for restricting polyadenylation to 3' UTRs.

The development of nanotheranostics for precision imaging-guided regulated cell death-mediated synergistic tumor therapy is still challenging. Herein, a novel multifunctional nanotheranostic agent, iRGD-coated maleimide-poly(ethylene glycol)-poly(lactic acid/glycolic acid)-encapsulated hydrophobic gold nanocages (AuNCs) and hydrophilic epigallocatechin gallate (EGCG) (PAuE) is developed for multispectral optoacoustic tomography (MSOT)-guided photothermal therapy (PTT) and chemotherapy. The portions of necroptotic and apoptotic tumor cells were 52.9 and 5.4%, respectively, at 6 h post-incubation after the AuNC-induced mild PTT treatment, whereas they became 14.0 and 46.1% after 24 h, suggesting that the switch of the cell death pathway is a time-dependent process. Mild PTT facilitated the release of EGCG which induces the downregulation of hypoxia-inducible factor-1 (HIF-1α) expression to enhance apoptosis at a later stage, realizing a remarkable tumor growth inhibition in vivo. Moreover, RNA sequence analyses provided insights into the significant changes in genes related to the cross-talk between necroptosis and apoptosis pathways via PAuE upon laser irradiation. In addition, the biodistribution and metabolic pathways of PAuE have been successfully revealed by 3D MSOT. Taken together, this strategy of first combination of EGCG and AuNC-based photothermal agent via triggering necroptosis/apoptosis to downregulate HIF-1α expression in a tumor environment provides a new insight into anti-cancer therapy.

Hypoxia is an important phenomenon due to insufficient oxygen supply in tumor tissue, and nitroreductase (NTR) is a characteristic enzyme used for evaluating hypoxia level in tumors. In this work, we designed a smart gold nanoparticle (AuNPs), modified by 16-mercaptoundecanoic acid (MHDA) and hypoxia-responsive 11-(2-nitro-1H-imidazol-1-yl)undecane-1-thiol (NI) ligand, that responds to the hypoxic environment in tumor sites. With proper surface ligand composition, the responsive nanoprobe exhibited aggregation through the bioreduction of the nitro group on NI ligands under hypoxic conditions and the UV-vis absorption peak maximum would shift to 630 nm from 530 nm, which acts as an "off-on" contrast agent for tumor hypoxic photoacoustic (PA) imaging. In vitro and in vivo experiments revealed that AuNPs@MHDA/NO₂ exhibited an enhanced PA signal in hypoxic conditions. This study demonstrates the potential of hypoxia-responsive AuNPs as novel and sensitive diagnostic agents, which lays a firm foundation for precise cancer treatment in the future.

The mass, chemical composition and toxicological properties of fine particulates (PM 2.5 ) emitted from cooking activities in three Hong Kong based restaurants and two simulated cooking experiments were characterized. Extracts from the PM 2.5 samples elicited significant biological activities [cell viability, generation of reactive oxygen species (ROS), DNA damage and inflammation effect (TNF-α)] in a dose-dependent manner. The composition of PAHs, oxygenated PAHs (OPAHs) and azaarenes (AZAs) mixtures differed between samples. The concentration ranges of the Σ30PAHs, Σ17OPAHs and Σ4AZAs and Σ7Carbonyls in the samples were 9627-23,452 pg m -3 , 503-3700 pg m -3 , 33-263 pg m -3 and 158 - 5328 ng m -3 , respectively. Cell viability caused by extracts from the samples was positively correlated to the concentration of benzo[a]anthracene, indeno[1,2,3-cd]pyrene and 1,4-naphthoquinone in the PM 2.5 extracts. Cellular ROS production (upon exposure to extracts) was positively correlated with the concentrations of PM 2.5 , decaldehyde, acridine, Σ17OPAHs and 7 individual OPAHs. TNF-α showed significant positive correlations with the concentrations of most chemical species (elemental carbon, 16 individual PAHs including benzo[a]pyrene, Σ30PAHs, SO 4 2- , Ca 2+ , Ca, Na, K, Ti, Cr, Mn, Fe, Cu and Zn). The concentrations of Al, Ti, Mn, Σ30PAHs and 8 individual PAHs including benzo[a]pyrene in the samples were positively correlated with DNA damage caused by extracts from the samples. This study demonstrates that inhalation of PM 2.5 emitted from cooking could result in adverse human health effects., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Corneal neovascularization (CNV) compromises corneal avascularity and visual acuity. Current clinical visualization approaches are subjective and unable to provide molecular information. Photoacoustic (PA) imaging offers an objective and non-invasive way for angiogenesis investigation through hemodynamic and oxygen saturation level (sO 2 ) quantification. Here, we demonstrate the utility of PA and slit lamp microscope for in vivo rat CNV model. PA images revealed untreated corneas exhibited higher sO 2 level than treatment groups. The PA results complement with the color image obtained with slit lamp. These data suggest PA could offer an objective and non-invasive method for monitoring CNV progression and treatment outcome through the sO 2 quantification., Competing Interests: The authors declare no conflicts of interest., (© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.)

The most advantageous and attractive property of photoacoustic imaging is its capability to visualize and differentiate multiple species according to their unique absorbance profiles simultaneously in a single mixture. We here report the pH-sensitive near-infrared (NIR) croconaine (Croc) dyes-loaded copolymeric PEG-PLGA nanoparticles (NPs) for in vivo multiplexed PA imaging and pH-responsive photothermal therapy (PTT) in an orthotopic xenograft model. PEG chains on the polymeric NPs shell were conjugated with iRGD in another set of NPs to realize efficient tumor targeting. The distribution and the intensity of two sets of iRGD-targeted and nontargeted NPs inside tumors are simultaneously imaged and monitored in vivo . Meanwhile, the utilization of iRGD-targeted PPC 815 NPs as a pH-active photothermal agent with promising tumor-inhibition efficacy was demonstrated. As a result, this nanoplatform is capable of assisting multiwavelength unmixing of PA imaging as well as providing remarkable photothermal ablation for anticancer treatment.

Palladium 2-di-cyclo-hexyl-phosphanyl-2',6'-diisopropoxybiphenyl (Pd-RuPhos) catalysts demonstrate high catalytic activity for Negishi cross-couplings of sterically hindered aryl halides, for Suzuki-Miyaura cross-couplings of tosyl-ated olefins, and for Buchwald-Hartwig amination of sterically hindered amines. The solid-state structure of the free RuPhos ligand, C 30 H 43 O 2 P, is reported herein for the first time. RuPhos crystallizes in a triclinic cell containing two independent mol-ecules of the phosphine without any lattice solvent. Pertinent bond metrics and comparisons to other phosphine ligands are presented. The structure of RuPhos will be of assistance in the use of this ligand in the design of cross-coupling catalysts., (© Carsch et al. 2021.)

Hydrogels are soft materials consisting of a three-dimensional network of polymer chains. Over the years, hydrogels with different compositions have been developed as drug carriers for diverse biomedical applications, ranging from cancer therapy and wound care to the treatment of neurodegenerative and inflammatory diseases. Most of these carriers, however, are designed only to deliver single agents. Carriers based on hydrogels for co-delivery of multiple agents, with the release rate of each of the co-delivered agents tunable, are lacking. This study reports a one-pot method of fabricating alginate-based complex fibers with the Janus morphology, with carboxymethyl cellulose sodium functioning as a polymeric modifier of the properties of each of the fiber compartments. By using malachite green and minocycline hydrochloride as model drugs, the generated fibers demonstrate the capacity of enabling the release profile of each of the co-delivered drugs to be precisely controlled. Along with their negligible toxicity and the retention of the activity of the loaded drugs, the complex fibers reported in this study warrant further development and optimization for applications that involve co-delivery of multiple agents., Competing Interests: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article., (© 2020 Shenyang Pharmaceutical University. Published by Elsevier B.V.)

Background: Palliative care aims to improve the quality of life for patients and their families, by helping them to cope with problems associated with illness. It targets four aspects of health: physical, psychological, social, and spiritual. Most of the current literature on palliative care is limited to the perspectives of health professionals. This study aims to investigate the views of outpatients receiving palliative care at the Hong Kong Queen Mary Hospital Hospice Centre (HKQMHHC), which offers palliative care services to cancer patients., Methods: This observational cross-sectional study was performed with the completion of a single paper- based original questionnaire over 18 afternoon clinic sessions on Thursdays and Fridays from December 2017 to February 2018 at the HKQMHHC. The questionnaire was designed to examine patients' perspectives; in particular, the Edmonton Symptom Assessment Scale (ESAS) was used to assess their symptoms. Descriptive and univariate analyses were performed., Results: One hundred patients attending HKQMHHC were included in the study. The study revealed that all the mean scores for aspects of care offered at the centre were above 8, on a scale of 0-10 with 0 being extremely inadequate and 10 being extremely adequate. Each respondent was able to identify an average of 1.82 of the 4 aspects of palliative care. Eighty-seven percent of respondents perceived the physical aspect of this care to be of the highest priority. A negative correlation (P<0.05) was found between the extent of symptoms experienced by the patient and their satisfaction towards the services offered., Conclusions: Patients generally held very positive attitudes, reflecting that the services sufficiently met their needs. However, owing to their rather limited knowledge, this may have restricted their perspectives to a largely superficial level, as many discerned palliative care to be simply targeting physical health with medical consultations. Considering the implications of the results, the addition of accessibility and education components to Hong Kong's current system of palliative care is crucial in the betterment of such services for patients. There should also be increased local coverage of palliative care services to facilitate convenience of access. With reference to the World Health Organisation (WHO) palliative care model, the inclusion of a continued spectrum of services, such as physical and mental health activities and psychosocial counselling, should be reinforced throughout the progression of disease so as to better help patients to cope with illness. The discovery of the relationship between extent of symptoms experienced and patients' satisfaction towards services provided is a new direction for further study.

Air pollution has shown to cause adverse health effects on mankind. Aging causes functional decline and leaves elderly people more susceptible to health threats associated with air pollution exposure. Elderly spend approximately 80% of their lifetime at home every day. To understand air pollution exposure, indoor air pollutants are the targets for consideration especially for the elderly population. However, indoor air monitoring for epidemiological studies requires a large population, is labor intensive and time consuming. As a result, a prediction model is necessary. For 3 consecutive days in summer and winter, 24-h average of mass concentrations of fine particulate matter (aerodynamic diameter <2.5 μm: PM 2.5 ) were measured in indoors for 116 households. A PM 2.5 prediction model for elderly households in Hong Kong has been developed by combining ambient PM 2.5 concentrations obtained from land use regression model and questionnaire-elicited information related to the indoor PM 2.5 sources. The fitted linear mixed-effects model is moderately predictive for the observed indoor PM 2.5 , with R 2  = 0.67 (or R 2  = 0.61 by cross-validation). The model shows indoor PM 2.5 was positively influenced by outdoor PM 2.5 levels. Meteorological factors (e.g. temperature and relative humidity) were related to the indoor PM 2.5 in a relatively complex manner. Congested living areas, opening windows for extended periods for ventilation and use of liquefied petroleum gas for cooking were the factors determining the ultimate indoor air quality. This study aims to provide information about controlling household air quality and can be used for future epidemiological studies associated with indoor air pollution in large population., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The chemical and cytotoxicity properties of fine particulate matter (PM 2.5 ) at indoor and outdoor environment were characterized in Xi'an, China. The mass concentrations of PM 2.5 in urban areas (93.29~96.13 μg m -3 for indoor and 124.37~154.52 μg m -3 for outdoor) were higher than suburban (68.40 μg m -3 for indoor and 96.18 μg m -3 for outdoor). The PM 2.5 concentrations from outdoor environment due to fossil fuel combustion were higher than indoor environment. An indoor environment without central heating demonstrated higher organic carbon-to-elemental carbon (OC / EC) ratios and n-alkanes values that potentially attributed to residential coal combustion activities. The cell viability of human epithelial lung cells showed dose-dependent decrease, while nitric oxide (NO) and oxidative potential showed dose-dependent increase under exposure to PM 2.5 . The variations of bioreactivities could be possibly related to different chemical components from different sources. Moderate (0.4 < R < 0.6) to strong (R > 0.6) correlations were observed between bioreactivities and elemental carbon (EC)/secondary aerosols (NO 3 - , SO 4 2- , and NH 4 + )/heavy metals (Ni, Cu, and Pb). The findings suggest PM 2.5 is associated with particle induced oxidative potential, which are further responsible for respiratory diseases under chronic exposure.

The physical, chemical and bioreactivity characteristics of fine particulate matter (PM 2.5 ) collected near (<1 km) two landfill sites and downwind urban sites were investigated. The PM 2.5 concentrations were significantly higher in winter than summer. Diurnal variations of PM 2.5 were recorded at both landfill sites. Soot aggregate particles were identified near the landfill sites, which indicated that combustion pollution due to landfill activities was a significant source. High correlation coefficients (r) implied several inorganic elements and water-soluble inorganic ions (vanadium (V), copper (Cu), chloride (Cl - ), nitrate (NO 3 - ), sodium (Na) and potassium (K)) were positively associated with wind flow from the landfill sites. Nevertheless, no significant correlations were also identified between these components against DNA damage. Significant associations were observed between DNA damage and some heavy metals such as cadmium (Cd) and lead (Pb), and total Polycyclic Aromatic Hydrocarbons (PAHs) during the summer. The insignificant associations of DNA damage under increased wind frequency from landfills suggested that the PM 2.5 loading from sources such as regional sources was possibly an important contributing factor for DNA damage. This outcome warrants the further development of effective and source-specific landfill management regulations for particulate matter production control to the city., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Chitosan (CS) is a biodegradable and biocompatible polysaccharide which displays immune-stimulatory effects and anti-bacterial properties to facilitate wound closure. Over the years, different CS-based dressings have been developed; however, most of them are not fully biodegradable due to the involvement of synthetic polymers during dressing fabrication. In addition, preparation of many of these dressings is laborious, and may impose damaging effects on fragile therapeutic molecules. The objective of this study is to address these problems by developing a tunable, biocompatible, and biodegradable CS-based dressing for wound treatment. The dressing is fabricated via electrostatic interactions between CS and carmellose (CM). Its swelling properties, erosion behavior, loading efficiency and drug release sustainability can be tuned by simply changing the CS/CM mass-to-mass ratio. Upon loaded with minocycline hydrochloride, the dressing effectively protects the wound in mice from infection and enhances wound closure. Regarding its high tunability and promising in vivo performance, our dressing warrants further development as a user-friendly dressing for use in wound care., (Copyright © 2019 Elsevier B.V. All rights reserved.)

A previously unknown abiotic humification pathway which is highly accelerated in frozen solution containing phenolic compounds and nitrite was investigated and proposed. The production of humic-like acids (HLA) and fulvic-like acids (FLA) was observed in the frozen solution (-20 °C) whereas it was negligible in aqueous solution (20 °C). Inorganic nitrogen was transformed into organic nitrogen during the humification process. Mass spectrometry (MS) and elemental analyses, including pyrolysis-GC/MS and FT-ion cyclotron resonance/MS, showed that humification products (HLA and FLA) have chemical structures and compositions similar to nature humic substances. The enhanced humification reaction could be attributed to the freeze-concentration effect, whereby nitrite ions in the unfrozen grain boundary region are transformed into nitrosonium ions which oxidize phenols to phenolic radicals. Confocal Raman microscopy confirmed that catechol and nitrite ions are preferentially concentrated at the ice grain boundary and electron paramagnetic resonance spectroscopic analysis of catechol/nitrite solution detected the phenolic radicals only in frozen solution, not in aqueous solution. The freezing-induced generation of phenolic radicals should lead to the formation of humic-like substances through polymerization. This study identifies and proposes a new humic formation pathway that might work as a model abiotic "bottom-up" mechanism in frozen environmental conditions.

Five types of crop residue (rice, wheat, corn, sorghum, and sugarcane) collected from different provinces in China were used to characterize the chemical components and bioreactivity properties of fine particulate matter (PM 2.5 ) emissions during open-burning scenarios. Organic carbon (OC) and elemental carbon (EC) were the most abundant components, contributing 41.7%-54.9% of PM 2.5 emissions. The OC/EC ratio ranged from 8.8 to 31.2, indicating that organic matter was the dominant component of emissions. Potassium and chloride were the most abundant components in the portion of PM 2.5 composed of water-soluble ions. The coefficient of divergence ranged from 0.27 to 0.51 among various emissions profiles. All samples exposed to a high PM 2.5 concentration (150 μg/mL) exhibited a significant reduction in cell viability (A549 lung alveolar epithelial cells) and increase in lactic dehydrogenase (LDH) and interleukin 6 levels compared with those exposed to 20 or 0 μg/mL. Higher bioreactivity (determined according to LDH and interleukin 6 level) was observed for the rice, wheat, and corn samples than for the sorghum straw samples. Pearson's correlation analysis suggested that OC, heavy metals (chromium, manganese, iron, nickel, copper, zinc, tin, and barium), and water-soluble ions (fluoride, calcium, and sulfate) are the components potentially associated with LDH production., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Aim: To establish a rabbit model of chronic ocular hypertension (OHT) by limbal buckling., Methods: Eighteen New Zealand White rabbits were involved and divided into three groups. A latex encircling band of 20, 25 or 35 mm was implanted behind the limbus in the right eye of each animal. The intraocular pressure (IOP) was monitored for 8 weeks, after which optic nerve damage was evaluated by fundus photography, optical coherence tomography (OCT) retrograde labelling and histology. Meanwhile, the anterior chamber angle (ACA) was examined by OCT and gonioscopy., Results: OHT was induced in all animals after surgery. The IOP peaked at 38.0±3.7, 32.0±3.9 and 24.1±6.5 mm Hg in groups 1, 2 and 3, respectively, and remained elevated for 22, 25 and 39 days on average, respectively. The elevated IOPs showed good consistency within 2 weeks, although the durations of high IOP varied moderately. The area ratio between the optic cup and disc (cup to disc area) was increased in 73% of the treated eyes, and the average changes were 0.10±0.13, 0.11±0.08 and 0.09±0.02 in groups 1, 2 and 3, respectively. The depth of the optic cup was also increased in the treated eyes, and the density of the retinal ganglion cells was reduced. Additionally, the ACA showed a dynamic change with IOP after the latter was reduced by paracentesis., Conclusion: Limbal buckling provides an effective method of producing chronic OHT and glaucomatous optic neuropathy in rabbits., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

The acidic microenvironment of tumor tissues has been proven to be a major characteristic for differentiation from normal tissues, thereby providing a desirable target for both disease diagnosis and functional imaging. We herein introduce a way to endow gold nanoparticles with aggregation behaviour induced by pH tuning. The nanoparticle surface was modified with two thiol conjugate molecules, which could smartly stabilize it at the pH of blood and normal tissues but induce aggregation in response to the acidic extracellular pH in tumor. The surface conjugate molecule composition effect was studied systematically, and at the optimal surface conjugate molecule composition, a pH-responsive active tumor-targeting c(RGDyk)-MHDA/LSC@AuNP nanoprobe was successfully obtained and showed a significantly enhanced contrast effect for both in vitro and in vivo photoacoustic (PA) imaging. Intravenous administration of our nanoprobe to U87MG tumor-bearing nude mice showed PA imaging contrasts almost 3-fold higher than those for the blocking group. Quantitative biodistribution data revealed that 9.7 μg g -1 of nanoprobe accumulated in the U87MG tumor 4 h post-injection. These findings might provide an effective strategy for developing new classes of intelligent and biocompatible contrast agents with a high efficiency for PA imaging and PA imaging-guided cancer therapy., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Nitrous acid (HONO) is an important precursor of OH radicals in the atmosphere. In urban areas, emissions from vehicles are the main source of air pollutants, including reactive nitrogen. Previously reported emission ratios of HONO (HONO/NO x ) from vehicles were measured in the late 1990s and need to be updated due to the significant changes in emission control technologies. We measured the emission ratio of a fleet of vehicles (38% diesel on average) from March 11 to 21, 2015, in a road tunnel in Hong Kong. The emission ratio of 1.24% (±0.35%) obtained is greater than the commonly adopted 0.8% or 0.3%. The elevated emission ratio is found to be related to the presence of vehicles equipped with diesel particle filters (DPFs). Positive correlation between HONO and black carbon (BC) shows that HONO and BC were emitted together, while the lack of correlation or even anticorrelation between HONO/NO x and BC indicates that the BC-mediated conversion of NO 2 to HONO in the dark was insignificant in the immediate vicinity of the emission sources., Implications: Vehicular emission is a key source for HONO in the urban atmosphere. However, the most commonly used emission ratio HONO/NO x in modeling studies was measured more than 15 years ago. Our tunnel study suggests that a mixed fleet nowadays has a higher emission ratio, possibly because of the diesel particle filter (DPF) retrofit program and the growing share of Euro IV or more advanced diesel vehicles. Our study also provides new insight into the role of black carbon in HONO formation from vehicles.

Airborne carbonyls were characterized from emitted indoor coal combustion. Samples were collected in Xuanwei (Yunnan Province), a region in China with a high rate of lung cancer. Eleven of 19 types of samples (58%) demonstrated formaldehyde concentrations higher than the World Health Organization exposure limit (a 30-min average of 100 μg m -3 ). Different positive significant correlations between glyoxal/methylglyoxal and formaldehyde/acetaldehyde concentrations were observed, suggesting possible different characteristics in emissions between two pairs of carbonyl compounds. A sample in the highest inhalation risk shows 29.2 times higher risk than the lowest sample, suggesting different coal sampling locations could contribute to the variation of inhalation risk. Inhabitants in Xuanwei also tend to spend more time cooking and more days per year indoors than the national average. The calculated cancer risk ranged from 2.2-63 × 10 -5 , which shows 13 types of samples at high-risk level. Cumulative effect in combination with different carbonyls could have contributed to the additive actual inhalation cancer risk. There is a need to explicitly address the health effects of environmentally relevant doses, considering life-long exposure in indoor dwellings.

Polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives (oxygenated PAHs: OPAHs and azaarenes: AZAs) were characterized in fine particulates (PM 2.5 ) emitted from indoor coal combustion. Samples were collected in Xuanwei (Yunnan Province), a region in China with a high rate of lung cancer. A sample from the community with the highest mortality contained the highest total concentration of PAHs, OPAHs and AZAs and posed the highest excess cancer risk from a lifetime of inhaling fine particulates. Positive correlations between total carbonyl-OPAHs, total AZAs and total PAHs implied that the emissions were dependent on similar factors, regardless of sample location and type. The calculated cancer risk ranged from 5.23-10.7 × 10 -3 , which is higher than the national average. The risk in each sample was ∼1-2 orders of magnitude higher than that deemed high risk, suggesting that the safety of these households is in jeopardy. The lack of potency equivalency factors for the PAH derivatives could possibly have underestimated the overall cancer risk., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Induction of PM 2.5 -associated lung cancer in response to EGFR-tyrosine kinase inhibitors (EGFR-TKI) remains unclear. Polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives (oxygenated PAHs: OPAHs and azaarenes: AZAs) were characterized in fine particulates (PM 2.5 ) emitted from indoor coal combustion. Samples were collected in Xuanwei (Yunnan Province), a region in China with a high rate of lung cancer. Human lung adenocarcinoma cells A549 (with wild-type EGFR) and HCC827 (with EGFR mutation) were exposed to the PM 2.5 , followed by treatment with EGFR-TKI. Two samples showed significant and dose-dependent reduction in the cell viability in A549. EGFR-TKI further demonstrated significantly decreased in cell viability in A549 after exposure to the coal emissions. Chrysene and triphenylene, dibenzo[a,h]anthracene, benzo[ghi]perylene, azaarenes and oxygenated polycyclic aromatic hydrocarbons (carbonyl-OPAHs) were all associated with EGFR-TKI-dependent reduced cell viability after 72-h exposure to the PM 2.5 . The findings suggest the coal emissions could influence the response of EGFR-TKI in lung cancer cells in Xuanwei., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The chemical and bioreactivity properties of fine particulate matter (PM2.5) emitted during controlled burning of different brands of incense were characterized. Incenses marketed as being environmentally friendly emitted lower mass of PM2.5 particulates than did traditional incenses. However, the environmentally friendly incenses produced higher total concentrations of non-volatile polycyclic aromatic hydrocarbons (PAHs) and some oxygenated polycyclic aromatic hydrocarbons (OPAHs). Human alveolar epithelial A549 cells were exposed to the collected PM2.5, followed by determining oxidative stress and inflammation. There was moderate to strong positive correlation (R > 0.60, p < 0.05) between selected PAHs and OPAHs against oxidative-inflammatory responses. Strong positive correlation was observed between interleukin 6 (IL-6) and summation of total Group B2 PAHs/OPAHs (∑7PAHs/ΣOPAHs). The experimental data indicate that emissions from the environmentally friendly incenses contained higher concentrations of several PAH and OPAH compounds than did traditional incense. Moreover, these PAHs and OPAHs were strongly correlated with inflammatory responses. The findings suggest a need to revise existing regulation of such products., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Agricultural liming materials are used to correct soil acidity and to improve plant growth and microbial functionality. A relatively low-grade agricultural lime was found to contain up to 125 mg kg(-1) arsenic (As), which is above any fertilizing materials code threshold. The color of the milled material is brown due to ample oxide dendrites. Microprobe elemental maps confirmed that these accessory oxide mineral phases are responsible for the elevated As concentrations in the limestone. The black Mn-bearing dendrites contain minor amounts of As, whereas the brown Fe-bearing dendrites contain the major part of the As inventory, with an Fe/As molar ratio around 100. Because the elemental maps represent only a few sample regions of interest (ROI), the results are corroborated by a bulk five-step sequential extraction of the lime, which suggests that a majority of the As is bound to acid-reducible phases. Because repartitioning of the As oxyanion during extraction cannot be ruled out, X-ray absorption spectroscopy with micrometer resolution (micro-XAS) was used as a solid-state speciation analysis approach. The micro-XAS results at the Fe K-edge for the selected ROIs revealed the brown dendrites to consist of ferrihydrite and goethite, whereas those at the As K-edge revealed that the pentavalent As species arsenate predominates, with As-Fe distance and coordination indicating binding as a mononuclear inner-spheric adsorbate complex. Batch experiments with soil exposed to submerged conditions of up to 41 d revealed a negligible As release rate from the lime (approximately 40 ng kg(-1) d(-1)). The results of this study corroborate regulatory codes that set the permissible As content in agricultural lime relative to the respective Fe content.

This study was to investigate the motor functional recovery process in chronic stroke during robot-assisted wrist training. Fifteen subjects with chronic upper extremity paresis after stroke attended a 20-session wrist tracking training using an interactive rehabilitation robot. Electromyographic (EMG) parameters, i.e., EMG activation levels of four muscles: biceps brachii (BIC), triceps brachii (TRI, lateral head), flexor carpiradialis (FCR), and extensor carpiradialis (ECR) and their co-contraction indexes (CI) were used to monitor the neuromuscular changes during the training course. The EMG activation levels of the FCR (11.1% of decrease from the initial), BIC (17.1% of decrease from the initial), and ECR (29.4% of decrease from the initial) muscles decreased significantly during the training (P<0.05). Such decrease was associated with decreased Modified Ashworth Scores for both the wrist and elbow joints (P<0.05). Significant decrease (P<0.05) was also found in CIs of muscle pairs, BIC&TRI (21% of decrease from the initial), FCR&BIC (11.3% of decrease from the initial), ECR&BIC (49.3% of decrease from the initial). The decreased CIs related to the BIC muscle were mainly caused by the reduction in the BIC EMG activation level, suggesting a better isolation of the wrist movements from the elbow motions. The decreased CI of ECR& FCR in the later training sessions (P<0.05) was due to the reduced co-contraction phase of the antagonist muscle pair in the tracking tasks. Significant improvements (P<0.05) were also found in motor outcomes related to the shoulder/elbow and wrist/hand scores assessed by the Fugl-Meyer assessment before and after the training. According to the evolution of the EMG parameters along the training course, further motor improvements could be obtained by providing more training sessions, since the decreases of the EMG parameters did not reach a steady state before the end of the training. The results in this study provided an objective and quantitative EMG measure to describe the motor recovery process during poststroke robot-assisted wrist for the further understanding on the neuromuscular mechanism associated with the recovery.

The latency estimation of cortico-muscular coherence (CMCoh) could provide valuable information, especially for the pathological study. However, the conduction time from the central cortical rhythm to peripheral oscillations has not been explored for stroke patients. In this study one recently proposed method, maximizing coherence, was applied into the coherence analysis to estimate the latency by which the extensor carpi radialis electromyographic signals lagged behind the electroencephalographic time series with seven subcortical stroke subjects. Significantly prolonged conduction time was found in affected sides compared with the unaffected sides. The interhemispheric spatial displacement was also calculated using electrodes projection optimization and spherical surface laplacian. The results showed that the CMCoh could help investigate the cerebral reorganization after stroke.

Whether afferent feedback contributes to the generation of cortico-muscular coherence (CMCoh) remains an open question. In the present study, a multivariate autoregressive (MVAR) model and partial directed coherence (PDC) were applied to investigate the causal influences between the central rhythm and electromyographic (EMG) signals in the process of CMCoh. The system modeling included activities from the contralateral and ipsilateral primary sensorimotor cortex (M1/S1), supplementary motor area (SMA) and the time series from extensor carpi radialis (ECR) muscles. The results showed that afferent sensory feedback could also play an important role for the generation of CMCoh. Meanwhile, significant coherence between the EMG signals and the activities in the SMA was found in two subjects out of five. Connectivity analysis revealed a significant descending information flow which possibly reflected direct recruitment on the motoneurons from the SMA to facilitate motor control.