Therapeutic applications of germline testing for cancer predisposition genes in Asia in the real world.

BACKGROUND: Germline genetic testing is traditionally carried out in patients suspected with hereditary cancer syndrome for enhanced cancer surveillance and/or preventive strategies, but is increasingly carried out for therapeutic indications. MATERIALS AND METHODS: We conducted a retrospective review of patients who underwent germline genetic testing at our centre to determine the prevalence of actionable pathogenic germline variants (PGV) and their clinical utility. RESULTS: From 2000 to 2022, 1154 cancer patients underwent germline testing, with the majority (945/1154) tested with multi-gene panels. Four hundred and eleven (35.6%) patients harboured a PGV and 334 (81%) were clinically actionable. BRCA1/2 accounted for 62.3% of actionable mutations, followed by mismatch repair (18%), and other homologous recombination repair (HRR) genes (19.7%). One hundred and fifty-two germline-positive patients have advanced cancers, and 79 received germline-directed therapies (poly ADP ribose polymerase inhibitors = 75; immunotherapy = 4). Median duration of immunotherapy and poly ADP ribose polymerase were 20.5 months (range 5-40 months) and 8 months (range 1-76 months), respectively. Among BRCA/HRR mutation carriers who received platinum-based chemotherapy, pathological complete response rate in the neoadjuvant setting was 53% (n = 17 breast cancers) and objective response rate was >80% in the advanced setting (n = 71). CONCLUSIONS: One-third of cancer patients tested carried a PGV and ∼80% were clinically actionable. Three-quarters of germline-positive advanced cancer patients received germline-directed therapies in the real world, underscoring the practical utility of germline testing to guide cancer therapeutics.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with early breast cancer.

The European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with early breast cancer were updated and published online in 2023, and adapted, according to previously established standard methodology, to produce the Pan-Asian adapted (PAGA) ESMO consensus guidelines for the management of Asian patients with early breast cancer. The adapted guidelines presented in this manuscript represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with breast cancer representing the oncological societies of China (CSCO), Indonesia (ISHMO), India (ISMPO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO), co-ordinated by ESMO and KSMO. The voting was based on scientific evidence and was independent of the current treatment practices, drug access restrictions and reimbursement decisions in the different Asian regions represented by the 10 oncological societies. The latter are discussed separately in the manuscript. The aim is to provide guidance for the optimisation and harmonisation of the management of patients with early breast cancer across the different regions of Asia, drawing on the evidence provided by both Western and Asian trials, whilst respecting the differences in screening practices, molecular profiling, as well as the age and stage at presentation. Attention is drawn to the disparity in the drug approvals and reimbursement strategies, between the different regions of Asia.

Propagation of surface plasma waves in metal films perforated with n × n lattices of holes (n = 2 to 72).

The propagation of surface plasma waves (SPWs) in 90 nm-thick Au films perforated with n × n square lattices of circular holes, referred to as n-metal photonic crystals (n-MPCs), is investigated. The hole period was set to 3 µm with n = 2, 4, 6, 8, 12, 18, 24, 36, and 72. For each n-MPC, the total number of holes was conserved to 5184 (= 72 × 72), which were grouped to form an Mn × Mn (Mn = 72/n) array of lattices, evenly spaced on 384 × 384 µm2. The n-MPCs were individually integrated on semi-insulating GaAs substrates. In the transmission through them, the primary peak by the SPW excited at the n-MPC/GaAs interface exhibits clear variation with n in its wavelength and intensity. It begins to appear for n ∼ 4 and its intensity is increased with n but saturated for n∼ x> 36 with Fano lineshape. These imply the SPW excitation is significantly affected by the boundary and number of holes in each lattice. Such lattice size-dependent transmission is compared with the absorption of the quantum dot infrared photodetectors identically coupled to the n-MPCs. In the absorption, the saturation of the peak intensity is observed for n∼ x> 24, lower than the ∼36 in the transmission. Their difference is characterized with the SPW propagation and decay that critically depend on the dielectric properties of devices as well as the number of holes and boundaries of each lattice in plasmonic excitation.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer.

The most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, staging and treatment of patients with metastatic breast cancer (MBC) was published in 2021. A special, hybrid guidelines meeting was convened by ESMO and the Korean Society of Medical Oncology (KSMO) in collaboration with nine other Asian national oncology societies in May 2022 in order to adapt the ESMO 2021 guidelines to take into account the differences associated with the treatment of MBC in Asia. These guidelines represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with MBC representing the oncological societies of China (CSCO), India (ISMPO), Indonesia (ISHMO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO). The voting was based on the best available scientific evidence and was independent of drug access or practice restrictions in the different Asian countries. The latter were discussed when appropriate. The aim of these guidelines is to provide guidance for the harmonisation of the management of patients with MBC across the different regions of Asia, drawing from data provided by global and Asian trials whilst at the same time integrating the differences in genetics, demographics and scientific evidence, together with restricted access to certain therapeutic strategies.

Spatiotemporal characteristics of ozone and the formation sensitivity over the Fenwei Plain.

High surface ozone (O3) levels affect human and environmental health. The Fenwei Plain (FWP), one of the critical regions for China's "Blue Sky Protection Campaign", has reported severe O3 pollution. This study investigates the spatiotemporal properties and the causes of O3 pollution over the FWP using high-resolution data from the TROPOspheric Monitoring Instrument (TROPOMI) from 2019 to 2021. This study characterizes spatial and temporal variations in O3 concentration by linking O3 columns and surface monitoring using a trained deep forest machine learning model. O3 concentrations in summer were 2-3 times higher than those found in winter due to higher temperatures and greater solar irradiation. The spatial distributions of O3 correlate with the solar radiation showing decreased trends from the northeastern to the southwestern FWP, with the highest O3 values in Shanxi Province and the lowest in Shaanxi Province. For urban areas, croplands and grasslands, the O3 photochemistry in summer is NOx-limited or in the transitional regime, while it is VOC-limited in winter and other seasons. Reducing NOx emissions would be effective for decreasing O3 levels in summer, while VOC reductions are necessary for winter. The annual cycle in vegetated areas included both NOx-limited and transitional regimes, indicating the importance of NOx controls to protect ecosystems. The O3 response to limiting precursors shown here is of importance for optimizing control strategies and is illustrated by emission changes during the 2020 COVID-19 outbreak.

Healthcare contacts with self-harm during COVID-19: An e-cohort whole-population-based study using individual-level linked routine electronic health records in Wales, UK, 2016-March 2021.

INTRODUCTION: Reduced rates of help seeking by those who self-harmed during the COVID-19 pandemic have been reported. OBJECTIVES: To understand changes in healthcare service contacts for self-harm during the COVID-19 pandemic across primary, emergency and secondary care. METHODS: This retrospective cohort study used routine electronic healthcare data for Wales, United Kingdom, from 2016 to March 14, 2021. Population-based data from primary care, emergency departments and hospital admissions were linked at individual-level. All Welsh residents aged ≥10 years over the study period were included in the study. Primary, emergency and secondary care contacts with self-harm at any time between 2016 and March 14, 2021 were identified. Outcomes were counts, incidence, prevalence and proportion of self-harm contacts relative to all contacts in each and all settings, as well as the proportion of people contacting one or more settings with self-harm. Weekly trends were modelled using generalised estimated equations, with differences between 2020 (to March 2021) and comparison years 2016-2018 (to March 2017-2019) quantified using difference in differences, from which mean rate of odds ratios (µROR) across years was reported. RESULTS: The study included 3,552,210 individuals over the study period. Self-harm contacts reduced across services in March and December 2020 compared to previous years. Primary care contacts with self-harm reduced disproportionately compared to non-self-harm contacts (µROR = 0.7, p<0.05), while their proportion increased in emergency departments during April 2020 (µROR = 1.3, p<0.05 in 2/3 comparison years) and hospital admissions during April-May 2020 (µROR = 1.2, p<0.05 in 2/3 comparison years). Despite this, those who self-harmed in April 2020 were more likely to be seen in primary care than other settings compared to previous years (µROR = 1.2, p<0.05). A lower proportion of those with self-harm contacts in emergency departments were subsequently admitted to hospital in December 2020 compared to previous years (µROR = 0.5, p<0.05). CONCLUSIONS: These findings suggest that those who self-harmed during the COVID-19 pandemic may have been less likely to seek help, and those who did so faced more stringent criteria for admission. Communications encouraging those who self-harm to seek help during pandemics may be beneficial. However, this needs to be supported by maintained provision of mental health services.

Analysis of Fano lineshape in extraordinary optical transmission.

We analyze the lineshape of the extraordinary optical transmission (EOT) associated with surface plasma waves (SPWs) excited with a metal photonic crystal (MPC), an Au film perforated with a 2.6 µm period, two-dimensional array of holes, integrated atop a GaAs substrate. From its asymmetry by Fano interference between transmission mediated by SPWs and direct transmission through individual holes, the resonance energy of the fundamental SPW propagating along the MPC/GaAs interface is extracted as 138.8 meV. This energy, the reference of the analysis, is slightly higher than the energy of the apparent peak of the EOT but lower than that of the Rayleigh anomaly closely related to the direct transmission. Its accuracy is verified with an identical MPC integrated on a quantum dot infrared photodetector coupled to the same SPW. Additional lineshape parameters, including relative strength of the two pathways to the transmission and SPW broadening, are determined from experiments. A condition of the Fano interference for EOT, critical to the intensity of its peak transmission, is established with their relations.

Anesthesia providers' perspectives on abortion provision: deductive findings from a qualitative study.

INTRODUCTION: A clinician's willingness to provide abortion care is complex. Anesthesia providers' experiences in providing anesthesia for abortion are not well studied. We aimed to explore anesthesia providers' perspectives on abortion provision. METHODS: We conducted semi-structured, qualitative interviews with currently practising anesthesia providers in the southeastern United States. Participants were recruited from scientific meetings of two regional anesthesiology organizations and via snowball sampling. A semi-structured interview guide included domains of standardized second trimester abortion cases and personal abortion attitudes. Data were coded and analyzed iteratively using both inductive and deductive approaches with MAXQDA software. Deductive results are presented. RESULTS: Fifteen participants completed interviews from February 2018 to February 2019, at which point thematic saturation occurred. Participants represented a range of provider type, years of experience, workplace setting, and prior abortion experience. Participants demonstrated varied personal abortion attitudes, with greater acceptability of maternal or fetal health indications than social or financial indications for abortion. Most participants were willing to provide anesthesia for abortion in specific clinical scenarios. CONCLUSIONS: Southeastern United States anesthesia providers hold a spectrum of personal views on abortion and are willing to provide anesthesia for second trimester abortion in specific clinical scenarios. Findings may inform future research or professional development activities, which are important efforts toward improving multidisciplinary abortion care.

Reproductive factors and breast arterial calcification: a systematic review and meta-analysis.

BACKGROUND: Breast arterial calcification (BAC) is a common incidental finding on screening mammography. Recent evidence suggests that BAC is associated with cardiovascular disease (CVD). We systematically reviewed the associations between BAC and reproductive factors (menopausal status, hormone replacement therapy [HRT] use, oral contraceptive [OC] use and parity). METHODS: MEDLINE and EMBASE databases, references of relevant papers and Web of Science were searched up to February 2020 for English-language studies that evaluated these associations. Study quality were determined and a random effects model was used to assess these associations. RESULTS: Nineteen observational studies (n = 47,249; three cohort studies, seven case-control studies, nine cross-sectional studies) were included. BAC was associated with menopause (nine studies; n = 15,870; odds ratio [OR] 2.67; 95% confidence interval [CI] 1.50-4.77) and parity (seven studies; n = 27,728; OR 2.50; 95% CI 1.68-3.71) and inversely with HRT use (10 studies; n = 33,156; OR 0.57; 95% CI 0.40-0.80). No association was found with OC use. Eleven studies were considered good in quality. Marked heterogeneity existed across all analyses. CONCLUSIONS: BAC is associated with HRT use, menopause and parity. However, careful interpretation is required as marked heterogeneity existed across all analyses. Traditional cardiovascular risk factors may need to be taken into account in future investigations of associations between BAC and reproductive factors. PROSPERO: CRD42020141644.

Use of local anesthesia for inguinal hernia repair has decreased over time in the VA system.

PURPOSE: In 2003, randomized trials demonstrated potentially improved outcomes when local instead of general anesthesia is used for inguinal hernia repair. Our study aimed to evaluate how the use of local anesthesia for this procedure changed over time following the publication of the trials' level 1 evidence. METHODS: We used the 1998-2018 Veterans Affairs Surgical Quality Improvement Program database to identify adults who underwent open, unilateral inguinal hernia repair under local or general anesthesia. Our primary outcome was the percentage of cases performed under local anesthesia. We used a time-series design to examine the trend and rate of change of the use of local anesthesia. RESULTS: We included 97,437 veterans, of which 22,333 (22.9%) had hernia surgery under local anesthesia. The median age of veterans receiving local anesthesia remained stable at 64-67 years over time. The use of local anesthesia decreased steadily, from 38.2% at the beginning year to 15.1% in the final year (P < 0.0001). The publication of results from randomized trials (in 2003) did not appear to increase the overall use or change the rate of decline in the use of local anesthesia. Overall, we found that the use of local anesthesia decreased by about 1.5% per year. CONCLUSION: The utilization of local anesthesia for inguinal hernia repair in the VA has steadily declined over the last 20 + years, despite data showing equivalence or superiority to general anesthesia. Future studies should explore barriers to the use of local anesthesia for hernia repair.

The chemical composition and toxicological effects of fine particulate matter (PM2.5) emitted from different cooking styles.

The mass, chemical composition and toxicological properties of fine particulates (PM2.5) emitted from cooking activities in three Hong Kong based restaurants and two simulated cooking experiments were characterized. Extracts from the PM2.5 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 PM2.5 extracts. Cellular ROS production (upon exposure to extracts) was positively correlated with the concentrations of PM2.5, 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, SO42-, Ca2+, 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 PM2.5 emitted from cooking could result in adverse human health effects.

Plasmonic-coupled quantum dot photodetectors for mid-infrared photonics.

A plasmonic-coupled, InAs-based quantum dot photodetector fabricated for mid-wave infrared photonics is reported. The detector is designed to provide a broadband absorption [full width at half maximum (FWHM) ≳ 2 µm] peaked at ∼5.5 µm, corresponding to transitions from the ground state of the quantum dot to the quasi-continuum resonance state above the quantum well. From the coupling of this transition to the surface plasma wave (SPW) excited by an Au film atop the detector, fabricated with a 1.5 µm-period, 2-dimensional array of square holes, a narrowband SPW enhancement peaked at 4.8 µm with an FWHM less than 0.5 µm is achieved. At ∼90 K, a peak responsivity enhanced ∼5× by the plasmonic coupling is observed. Simulation reveals that this enhancement corresponds to collecting ∼6% of the incident light; ∼40% of the total absorption by the SPW excitation at the peak wavelength.

A Mechanized Pediatric Elbow Joint Powered by a De-Based Artificial Skeletal Muscle.

To increase the acceptability of exoskeletons, there is growing attention toward finding an alternative soft actuator that can safely perform at close vicinity of the human body. In this study, we investigated the capability of the dielectric elastomer actuators (DEAs), for muscle-like actuation of rehabilitation robots. First, an artificial skeletal muscle was configured using commercially available stacked DEAs arranged in a 3x4 array of three parallel fibers consisting of four DEAs connected in series. The shortening and force generation capabilities of this artificial muscle were then measured. An alternate 3x5 version of this muscle was mounted on the forearm of an upper extremity phantom model to actuate its elbow joint. The actuation capability of this muscle was then tested under various tensile loads, 1 N to 4 N, placed at the center of mass of the forearm+hand of the phantom model. The active range of motion and angular velocity of the phantom model's tip of the hand were measured using a motion capture system. The 3×4 artificial muscle produced 30.47 N of force and 5.3 mm of maximum shortening. The 3x5 artificial muscle was capable of actuating the elbow flexion 19.5º with 16.2 º/s angular velocity in the sagittal plane, under a 1 N tensile load. The active range of motion was substantially reduced as the tensile loads increased, which limits the capability of these muscles in the current upper extremity exoskeleton design.

Vision loss in an immunocompetent child post varicella infection: A case report.

Chickenpox may lead to several neurological complications. Optic neuritis is one of the complications which has rarely been described, especially in immunocompetent individuals. We report a case of an 11-year-old immunocompetent girl who presented with sudden onset bilateral vision loss three weeks after varicella eruption. Ophthalmic examination revealed bilateral optic disc edema. Diagnosis of bilateral optic neuritis secondary to varicella was established based upon the preceding medical history, supported with clinical and radiological findings.

Quantum efficiency of plasmonic-coupled quantum dot infrared photodetectors for single- color detection: the upper limit of plasmonic enhancement.

We report a measurement of the quantum efficiency for a surface plasma wave (SPW)-coupled InAs/In0.15Ga0.85As/GaAs dots-in-a-well (Dwell) quantum dot infrared photodetector (QDIP) having a single-color response at ∼10 µm. A gold film perforated with a square array of complex, non-circular apertures is employed to manipulate the near-fields of the fundamental SPW. The quantum efficiency is quantitatively divided into absorption efficiency strongly enhanced by the SPW, and collection efficiency mostly independent of it. In the absorption efficiency, the evanescent near-fields of the fundamental SPW critically enhances QDIP performance but undergoes the attenuation by the absorption in the Dwell that ultimately limits the quantum efficiency. For the highest quantum efficiency available with plasmonic coupling, an optimal overlap between Dwell and SPW near-fields is required. Based on experiment and simulation, the upper limit of the plasmonic enhancement in quantum efficiency for the present device is addressed.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the management of patients with early breast cancer: a KSMO-ESMO initiative endorsed by CSCO, ISMPO, JSMO, MOS, SSO and TOS.

In view of the planned new edition of the most recent version of the European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of primary breast cancer published in 2015, it was decided at the ESMO Asia Meeting in November 2018, by both the ESMO and the Korean Society of Medical Oncology (KSMO), to convene a special face-to-face guidelines meeting in 2019 in Seoul. The aim was to adapt the latest ESMO 2019 guidelines to take into account the ethnic and geographical differences associated with the treatment of early breast cancer in Asian patients. These guidelines represent the consensus opinions reached by experts in the treatment of patients with early breast cancer representing the oncology societies of Korea (KSMO), China (CSCO), India (ISMPO) Japan (JSMO), Malaysia (MOS), Singapore (SSO) and Taiwan (TOS). The voting was based on scientific evidence, and was independent of both the current treatment practices, and the drug availability and reimbursement situations, in the individual participating Asian countries.

Natural clinical course of progressive supranuclear palsy in Chinese patients in Hong Kong.

INTRODUCTION: Progressive supranuclear palsy (PSP) is a common type of atypical parkinsonism. To the best of our knowledge, there has been no study of its natural clinical course among Chinese patients. METHODS: This retrospective study included 21 patients with PSP who had radiological evidence of midbrain atrophy (confirmed by magnetic resonance imaging) from the geriatrics clinics of Queen Mary Hospital and Tuen Mun Hospital. Clinical information was retrieved from clinical records, including age at onset, age at presentation, age at death, duration of symptoms, level of education, sex, presenting scores on Cantonese version of Mini-Mental State Examination, clinical symptoms, and history of levodopa or dopamine agonist intake and response. Clinical symptoms were clustered into the following categories and the dates of development of these symptoms were determined: motor symptoms, bulbar symptoms, cognitive symptoms, and others. RESULTS: Motor symptoms developed early in the clinical course of disease. Cox proportional hazards modelling showed that the number of episodes of pneumonia, time to vertical gaze palsy, and presence of pneumonia were predictive of mortality. Apathy, dysphagia, pneumonia, caregiver stress, and pressure injuries were predictive of mortality when analysed as time-dependent covariates. There was a significant negative correlation between the age at presentation and time to mortality from presentation (Pearson correlation=-0.54, P=0.04). Approximately 40% of caregivers complained of stress during the clinical course of disease. CONCLUSION: Important clinical milestones, including the development of dysphagia, vertical gaze palsy, significant caregiver stress, pressure injuries, and pneumonia, may guide advanced care planning for patients with PSP.

Benchmarking of a Commercially Available Stacked Dielectric Elastomer as an Alternative Actuator for Rehabilitation Robotic Exoskeletons.

Recent commercial availability of a stacked dielectric elastomer actuator (SDEA) has opened up possibilities of their use as "artificial muscles" for rehabilitation robots and powered exoskeleton devices. Made by CTsystems, this actuator (CT_SDEA) is made from soft materials, and offers a lightweight and acoustically noiseless alternative to DC motor actuators used in conventional rehabilitation robotic systems. The purpose of the present work was to benchmark the electromechanical properties of CT-SDEAs to assess its capabilities and limitations for mechanizing rehabilitation robots. The CT-SDEAs tested in this study showed 21 ms electrometrical delay, and their calculated strain-rate was 660 %/s. They could generate 21.74 N of force and have a 426 W/kg power-to-mass ratio. Their longitudinal strain was measured at 3.3%. Additionally, their steady state current consumption was measured 39 $\mu$ A. CT-SDEAs' fast response, short electromechanical delay and high strain-rate, make them highly suitable for closed-loop control. Additionally, their force generation capability, fast response, high power-to-mass ratio, and low steady state power consumption make them a strong candidates for exoskeleton applications. It's longitudinal strain (3.3%) however, was less than that of skeletal muscle (20%). Depending on the application, their use may require the addition of mechanical linkages, for force to displacement conversion.

Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production.

MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0 fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

The effects of particle-induced oxidative damage from exposure to airborne fine particulate matter components in the vicinity of landfill sites on Hong Kong.

The physical, chemical and bioreactivity characteristics of fine particulate matter (PM2.5) collected near (<1 km) two landfill sites and downwind urban sites were investigated. The PM2.5 concentrations were significantly higher in winter than summer. Diurnal variations of PM2.5 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 (NO3-), 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 PM2.5 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.