Does dose reduction of afatinib affect treatment outcomes of patients with EGFR-mutant metastatic non-small cell lung cancer in real-world clinical practice?

Background

Afatinib can be started at a dose lower than the recommended starting dose of 40 mg/day for the treatment of epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC), however treatment outcomes in real-world clinical practice remains unclear.

Methods

This retrospective study of patients with NSCLC from 18 major hospitals (public, private or university teaching hospitals) enrolled in Malaysia's National Cardiovascular and Thoracic Surgical Database (NCTSD) assessed the efficacy of lower doses of afatinib on treatment outcomes in a real-world clinical practice. Data on clinical characteristics, afatinib dosing, and treatment outcomes for patients included in NCTSD from 1st January 2015 to 31st December 2020 were analyzed.

Results

Of the 133 patients studied, 94.7% had adenocarcinoma. Majority of the patients (60.9%) had EGFR exon 19 deletion and 23.3% had EGFR exon 21 L858R point mutation. The mean age of patients was 64.1 years and majority (83.5%) had Eastern Cooperative Oncology Group performance status of 2-4 at diagnosis. The most common afatinib starting doses were 40 mg (37.6%), 30 mg (29.3%), and 20 mg (26.3%) once daily (OD), respectively. A quarter of patients had dose reduction (23.3%) due to side effects or cost constraints. Majority of the patients had partial response to afatinib (63.2%) whilst 2.3% had complete response. Interestingly, the objective response rate was significantly higher (72.3%) with afatinib OD doses of less than 40 mg compared to 40 mg (54.0%) (P=0.032). Patients on lower doses of afatinib were two times more likely to achieve an objective response [odds ratio =2.64; 95% confidence interval (CI): 1.20-5.83; P=0.016]. These patients had a numerically but not statistically longer median time to treatment failure (TTF). Median TTF (95% CI) for the overall cohort was 12.4 (10.02-14.78) months. Median overall survival (95% CI) was 21.30 (15.86-26.75) months.

Conclusions

Lower afatinib doses (<40 mg OD) could be equally effective as standard dose in patients with EGFR-mutant advanced NSCLC and may be more suited to Asian patients, minimizing side effects that may occur at higher dosages of afatinib leading to dose interruptions and affecting treatment outcomes.

Characterization of chemical components of fresh and aged aerosol from vehicle exhaust emissions in Hong Kong

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, and glutaric 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.

Real-World Treatment and Outcomes of ALK-Positive Metastatic Non-Small Cell Lung Cancer in a Southeast Asian Country

Purpose

Anaplastic lymphoma kinase (ALK) inhibitors are associated with good overall survival (OS) for ALK-positive metastatic non-small cell lung cancer (NSCLC). However, these treatments can be unavailable or limited by financial constraints in developing countries. Using data from a nationwide lung cancer registry, the present study aimed to identify treatment patterns and clinical outcomes of ALK-positive NSCLC in Malaysia.

Methods

This retrospective study examined data of patients with ALK-positive NSCLC from 18 major hospitals (public, private, or university teaching hospitals) throughout Malaysia between January 1, 2015 and December 31, 2020 from the National Cardiovascular and Thoracic Surgical Database (NCTSD). Data on baseline characteristics, treatments, radiological findings, and pathological findings were collected. Overall survival (OS) and time on treatment (TOT) were calculated using the Kaplan-Meier method.

Results

There were 1581 NSCLC patients in the NCTSD. Based on ALK gene-rearrangement test results, only 65 patients (4.1%) had ALK-positive advanced NSCLC. Of these 65 patients, 59 received standard-of-care treatment and were included in the analysis. Crizotinib was the most commonly prescribed ALK inhibitor, followed by alectinib and ceritinib. Patients on ALK inhibitors had better median OS (62 months for first-generation inhibitors, not reached at time of analysis for second-generation inhibitors) compared to chemotherapy (27 months), but this was not statistically significant (P=0.835) due to sample-size limitations. Patients who received ALK inhibitors as first-line therapy had significantly longer TOT (median of 11 months for first-generation inhibitors, not reached for second-generation inhibitors at the time of analysis) compared to chemotherapy (median of 2 months; P<0.01).

Conclusion

Patients on ALK inhibitors had longer median OS and significantly longer TOT compared to chemotherapy, suggesting long-term benefit.

Outcomes of Patients with EGFR-Mutant Advanced NSCLC in a Developing Country in Southeast Asia

Background

Although first- and second-generation EGFR TKIs are considered first-line treatment in EGFRm+ NSCLC, most patients develop resistance and progress, commonly, EGFR T790M mutation. The third-generation EGFR-TKI has demonstrated efficacy in patients with progressive disease harboring the T790M mutation and in the first-line setting, bypassing this mode of resistance. The primary objectives of this study are to describe the proportion of EGFRm+ NSCLC patients treated with first-, second- and third-generation EGFR TKIs, and cytotoxic chemotherapy in the first-line setting, and the time on treatment for each category. Secondary objectives are to determine the dropout rate, the rates for T790M mutation testing at disease progression and the type of subsequent treatment.

Methods

This multicenter retrospective study utilized data from the Malaysian Lung Cancer Registry that actively registers all lung cancer patients ≥18 years, with primary lung cancer confirmed histologically or cytologically. All patients diagnosed with advanced stages (ie stages IIIB, IIIC and IV) EGFRm+ NSCLC from 1st of January 2015 to 31st December 2019 were included.

Results

Of 406 patients with EGFRm+ NCSLC, 351 were treated. Types of first-line treatment were as follows: EGFR-TKIs (first generation - 54.1%, second generation - 25.6% and third-generation - 12.5%) and chemotherapy (7.7%). The median time of treatment for each generation of EGFR-TKI was 12 months, 12 months and 24 months, and 2 months for chemotherapy. The dropout rate was 28.7% (n = 101). Nearly half (49.4%) of patients who were on first- or second-generation EGFR-TKI had further genetic testing via liquid or tissue biopsies upon disease progression. About 24.9% of those who developed disease progression after first- or second-generation EGFR TKI were started on a third-generation EGFR TKI.

Conclusion

In the real-world, the management of EGFRm+ advanced NSCLC patients in an Asian cost-restrictive setting may adversely affect the choice of first-line therapy, time on each line of treatment and subsequently the overall survival of patients.

Programmed death-ligand 1 expression and use of immune checkpoint inhibitors among patients with advanced non-small-cell lung cancer in a resource-limited country

Introduction

Immune checkpoint inhibitor (ICI) therapy is an established treatment for advanced non‐small‐cell lung cancer (NSCLC) and programmed death ligand‐1 (PD‐L1) expression is a recognized biomarker to determine response to therapy. We retrospectively analyzed NSCLC patients in the Malaysia Lung Cancer Registry (MLCR) and report on the clinical characteristics associated with PD‐L1 expression and ICI use in Malaysia, a low‐ to middle‐income country.

Methods

All 901 NSCLC patients in the MLCR who were diagnosed from January 1, 2017 to December 31, 2020 from 14 hospitals across the country were analyzed.

Results

Out of 901 patients, 505 had PDL‐1 testing done with complete data available only in 489 patients. The most common histology was adenocarcinoma (84.7%) followed by squamous cell carcinoma (10.2%). The majority (95%) presented with stage 3 or 4. The number and percentage of patients with PDL‐1 tumor proportion scores of ≥50%, 1–49%, and <1% were 138 (28.2%), 158 (32.3%), and 193 (39.5%), respectively. In multivariate analysis, the presence of genomic mutation is the only independent characteristic associated with negative PD‐L1 expression (crude odds ratio 0.579, 95% confidence interval 0.399–0.840, p = 0.004). Of 292 patients eligible for ICI therapy, only 100 patients (34.2%) received ICIs. Seventy‐eight patients received ICI therapy as first‐line treatment, 15 patients as second‐line treatment, and 7 patients as third‐line treatment.

Conclusions

This is the first analysis on PD‐L1 expression and ICI use in Malaysia. Despite the proven efficacy of ICI therapy, only 56% of our patients had PD‐L1 tests performed and only 34.2% of eligible patients received ICIs.

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 (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, SO₄^2-, 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 PM_2.5 emitted from cooking could result in adverse human health effects.

Oncologist-led BRCA counselling improves access to cancer genetic testing in middle-income Asian country, with no significant impact on psychosocial outcomes

BACKGROUND

Identifying patients with BRCA mutations is clinically important to inform on the potential response to treatment and for risk management of patients and their relatives. However, traditional referral routes may not meet clinical needs, and therefore, mainstreaming cancer genetics has been shown to be effective in some high-income and high health-literacy settings. To date, no study has reported on the feasibility of mainstreaming in low-income and middle-income settings, where the service considerations and health literacy could detrimentally affect the feasibility of mainstreaming.

METHODS

The Mainstreaming Genetic Counselling for Ovarian Cancer Patients (MaGiC) study is a prospective, two-arm observational study comparing oncologist-led and genetics-led counselling. This study included 790 multiethnic patients with ovarian cancer from 23 sites in Malaysia. We compared the impact of different method of delivery of genetic counselling on the uptake of genetic testing and assessed the feasibility, knowledge and satisfaction of patients with ovarian cancer.

RESULTS

Oncologists were satisfied with the mainstreaming experience, with 95% indicating a desire to incorporate testing into their clinical practice. The uptake of genetic testing was similar in the mainstreaming and genetics arm (80% and 79%, respectively). Patient satisfaction was high, whereas decision conflict and psychological impact were low in both arms of the study. Notably, decisional conflict, although lower than threshold, was higher for the mainstreaming group compared with the genetics arm. Overall, 13.5% of patients had a pathogenic variant in BRCA1 or BRCA2, and there was no difference between psychosocial measures for carriers in both arms.

CONCLUSION

The MaGiC study demonstrates that mainstreaming cancer genetics is feasible in low-resource and middle-resource Asian setting and increased coverage for genetic testing.

Metallic elements and Pb isotopes in PM2.5 in three Chinese typical megacities: spatial distribution and source apportionment

Heavy metal pollution in fine particulate matter (PM_2.5) is a serious environmental and health concern in China, particularly during winter. Here, we detected 40 elements in 24 h integrated daily PM_2.5 samples collected in January 2014 from three typical Chinese metropolises (Beijing, Changchun, and Chengdu) to reflect elemental spatial variations, local sources, and regional transport. The measured elemental concentrations in Changchun were 11.1% and 48.4% higher than those in Beijing and Chengdu, respectively. Thus, PM_2.5 from Changchun exhibited high levels and diversity in the elemental profile (characterized by high concentrations of industrial emission elemental markers). The results of elemental ratios and Pb isotopes proved that, except for a coal combustion source, vehicular emissions contributed more to PM_2.5 heavy metals in Beijing than in the other two cities; Changchun PM_2.5 elements received large contributions from industrial sources, including iron and steel manufacturing, and automobile industry. Moreover, crustal dust from long-range transport of regional air masses from the northwest regions of China played a crucial role in determining elemental levels in Beijing and Changchun, accounting for more than 50% of source intensity. However, a specific dominant source was not determined in Chengdu; the contribution of anthropogenic dust, mainly from construction activities, needs to be paid attention in Chengdu eastern area. This study contributed to enhancing our understanding of elemental spatial distribution characteristics and sources and to setting more judicious standards and strategies for PM_2.5 bound heavy metals in China.

Prediction model for air particulate matter levels in the households of elderly individuals in Hong Kong

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 R² = 0.67 (or R² = 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.

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 (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 (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 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.

Source contributions of surface ozone in China using an adjoint sensitivity analysis

Air pollution has become an adverse environmental problem in China, resulting in serious public health impacts. This study advanced and applied the CMAQ adjoint model to quantitatively assess the source-receptor relationships between surface ozone (O₃) changes over different receptor regions and precursor emissions across all locations in China. Five receptor regions were defined based on the administrative division, including northern China (NC), southern China (SC), Pearl River Delta region (PRD), Yangtz River Delta region (YRD), and Beijing-Tianjin-Hebei region (BTH). Our results identified the different influential pathways of atmospheric processes and emissions to O₃ pollution. We found that the atmospheric processes such as horizontal and vertical advection could offset the O₃ removal through chemical reactions in VOC-limited areas inside the receptor regions. In addition, O₃ pollution can be induced by transport of O₃ directly or its precursors. Our results of relative source contributions to O₃ show that transboundary O₃ pollution was significant in SC, NC and YRD, while the O₃ pollution in PRD and BTH were more contributed by local sources. Anhui, Hubei and Jiangsu provinces were the three largest source areas of NO_x and VOC emissions to O₃ in SC (>52%) and YRD (>69%). NO_x and VOC emissions from Tianjin and Beijing were the largest contributors to O₃ in NC (>34%) and BTH (>51%). PRD was the dominant source areas of NO_x (>89%) and VOC emissions (~98%) to its own regional O₃.

Relationship between patient-reported outcomes and clinical outcomes in metastatic castration-resistant prostate cancer: post hoc analysis of COU-AA-301 and COU-AA-302

Background

Patient-reported outcomes (PROs) are used to assess benefit-risk in drug development. The relationship between PROs and clinical outcomes is not well understood. We aim to elucidate the relationships between changes in PRO measures and clinical outcomes in metastatic castration-resistant prostate cancer (mCRPC).

Patients and methods

We investigated relationships between changes in self-reported fatigue, pain, functional well-being (FWB), physical well-being (PWB) and prostate cancer-specific symptoms with overall survival (OS) and radiographic progression-free survival (rPFS) after 6 and 12 months of treatment in COU-AA-301 (N = 1195) or COU-AA-302 (N = 1088). Eligible COU-AA-301 patients had progressed after docetaxel and had Eastern Cooperative Oncology Group performance status (ECOG PS) ≤ 2. Eligible COU-AA-302 patients had no prior chemotherapy and ECOG PS 0 or 1. Patients were treated with abiraterone acetate (1000 mg/day) plus prednisone (10 mg/day) or prednisone alone daily. Association between self-reported fatigue, pain and functional status, and OS and/or rPFS, using pooled data regardless of treatment, was assessed. Cox proportional hazard regression modeled time to death or radiographic progression.

Results

In COU-AA-301 patients, PRO improvements were associated with longer OS and longer time to radiographic progression versus worsening or stable PROs (P < 0.0001). In multivariate models, all except pain intensity remained associated with OS. Pain intensity, PWB and FWB improvements remained associated with rPFS. In COU-AA-302 patients, worsening PROs were associated with higher likelihood of radiographic progression (P ≤ 0.025) compared with improved or stable PROs. In multivariate models, worsening PWB remained associated with worse rPFS. The 12-month analysis confirmed the 6-month results.

Conclusions

PROs are significantly associated with clinically relevant time-to-event efficacy outcomes in clinical trials and may complement and help predict traditional clinical practice methods for monitoring patients for disease progression.

Epidemiology of lung cancer: A joinpoint analysis of temporal incidence and mortality trends in 38 countries

e13091

Background: Lung cancer is the leading cause of cancer death worldwide. We examined the correlation between lung cancer incidence/mortality and country-specific socioeconomic development, and evaluated the most recent global patterns and trends of this cancer in 38 countries. Methods: We retrieved age-standardized incidence rates of lung cancer in 2012 from the GLOBOCAN database. Temporal patterns were assessed for all countries obtained from the Cancer Incidence in Five Continents volumes I-X and the WHO mortality database. Simple linear regression analysis was used to evaluate their correlations with Human Development Index (HDI) and Gross Domestic Product (GDP) per capita. The average annual percent change (AAPC) of the incidence and mortality trends in the most recent 10 years were evaluated from join-point regression analysis according to country and gender. The statistical significance of AAPC was ascertained comparing with zero, and all insignificant AAPCs were regarded as having “stable trends”. Results: The global incidence and mortality of lung cancer varied by 31-fold. Country-specific HDI was strongly correlated with age-standardized incidence (r = 0.70) and mortality (r = 0.67), and so was GDP per capita to a lesser extent (r = 0.24 to 0.55) (all p < 0.001). Among men, 22 and 30 (out of 38 and 36) countries showed declining incidence and mortality trends, respectively; whilst among women, 19 and 16 countries showed increasing incidence and mortality trends, respectively. The AAPCs ranged from -2.8 to -0.6 (incidence) and -3.6 to -1.1 (mortality) among countries with declining trend in men, whereas the AAPC range was 0.4 to 8.9 (incidence) and 1 to 4.4 (mortality) among countries with increasing trends in women. Among women, Brazil, Spain and Cyprus had the greatest incidence increase, and all countries in Western, Southern and Eastern Europe had increasing mortality. Conclusions: Countries with higher socioeconomic development had higher lung cancer incidence and mortality. The incidence and mortality rates of lung cancer were increasing in many countries among women but declining in most countries among men, highlighting the need for regular surveillance and global preventive measures.

Cancer risk from polycyclic aromatic compounds in fine particulate matter generated from household coal combustion in Xuanwei, China

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.

Characterization of chemical components and bioreactivity of fine particulate matter (PM2.5) during incense burning

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.

Spatiotemporal distribution of carbonyl compounds in China

A sampling campaign was carried out at nine Chinese cities in 2010/2011. Fifteen monocarbonyls (C# = 1-9) were quantified. Temperature is the rate-determining factor of the summertime carbonyl levels. The carbonyl emissions in winter are mainly driven by the primary anthropogenic sources like automobile. A molar ratio of propionaldehyde to nonaldehyde is a barometer of the impact of atmospheric vegetation emission which suggesting that strong vegetation emissions exist in summer and high propionaldehyde abundance is caused by fossil fuel combustion in winter. Potential health risk assessment of formaldehyde and acetaldehyde was conducted and the highest cumulative risks were observed at Chengdu in summer and Wuhan in winter. Because of the strong photochemical reaction and large amount of anthropogenic emissions, high concentrations of carbonyl compounds were observed in Chengdu. The use of ethanol-blended gasoline in Wuhan is the key reason of acetaldehyde emission and action should be taken to avoid potential health risks.

Chemical and biological characterization of air particulate matter 2.5, collected from five cities in China

Fifteen polycyclic aromatic hydrocarbons (PAHs) in PM2.5 samples collected in five different cities (Hong Kong (HK), Guangzhou (GZ), Xiamen (XM), Xi'an (XA) and Beijing (BJ)) in China in the winter 2012-13 [corrected] were analyzed by gas chromatography-mass spectrometry. The biological effects of organic extracts were assayed using the human bronchial epithelial cells BEAS-2B. All sixteen priority PAHs can be found in the PM2.5 samples of XA and BJ, but not in HK, GZ and XM, demonstrating the differential spatial source and distribution of PAHs. Our results showed that the total PAHs ranged from 3.35 to 80.45 ng/m(3) air, leading by BJ, followed by XA, XM, GZ and HK. In the cell culture study, transcript levels of pro-inflammatory cytokine interleukin-6 (IL-6), CYP1A1 and CYP1B1 were found to be induced in the treatment. The cells exposed to extracts from XA and BJ demonstrated significant migratory activities, indicating a sign of increase of tumorigenicity.

Carotid dosimetry for T1 glottic cancer radiotherapy

OBJECTIVE

Radiotherapy for T1 glottic cancer is commonly delivered using a lateral parallel opposed pair of megavoltage photon fields. There is increasing reported evidence of cerebrovascular events due to radiation-induced carotid stenosis. An alternative field arrangement is to use an anterior oblique technique. This study compares the carotid dosimetry between the two techniques and reviews the evidence for the risk of radiation-induced vascular events.

METHODS

The radiotherapy plans of 10 patients with T1 glottic cancer treated with an anterior oblique technique were examined for carotid dose. Alternative plans were then created using a parallel opposed pair of fields and the dose to the carotids compared. All patients received 50 Gy in 16 fractions treating once daily, for 5 days in a week.

RESULTS

The average of the mean dose to the carotids with the anterior oblique technique was 21 Gy compared with 37 Gy using the lateral parallel opposed pair arrangement (p < 0.0001).

CONCLUSION

An anterior oblique field arrangement for the treatment of T1 glottic cancer results in a significantly lower radiation dose to the carotid arteries, which may be clinically important in terms of reducing the risk of cerebrovascular events in long-term survivors.

ADVANCES IN KNOWLEDGE

Although the anterior oblique technique for treating early glottic cancers is well described, and it is predictable that the dose received by the carotid arteries should be lower with this technique, to our knowledge this is the first study to quantify that reduction in dose with a series of patients.

Seasonal variations of monocarbonyl and dicarbonyl in urban and sub-urban sites of Xi'an, China

Seventeen airborne carbonyls including monocarbonyls and dicarbonyls were determined in urban and sub-urban sites of Xi'an, China in three seasons in 2010. In winter, acetone was the most abundant carbonyl in the urban site due to usage of organic solvents in constructions and laboratories and its slower atmospheric removal mechanisms by photolysis and reaction with hydroxyl radical than those of formaldehyde and acetaldehyde. In the sub-urban site, acetaldehyde was the most abundant carbonyl, followed by formaldehyde and acetone. During summer, however, formaldehyde was the most dominant carbonyl in both sites. The photooxidations of a wide range of volatile organic compounds (VOCs) yielded much more formaldehyde than other carbonyls under high solar radiation and temperature. In the urban site, the average concentrations of dicarbonyls (i.e., glyoxal and methyglyoxal) in spring and summer were higher than that in winter. Transformation of aromatic VOCs emitted from fuel evaporation leads to the formation of 1,2-dicarbonyls. A reverse trend was observed in sub-urban sites, as explained by the relatively low abundances and accumulations of VOC precursors in the rural atmosphere during warm seasons. Moreover, cumulative cancer risk based on measured outdoor carbonyls (formaldehyde and acetaldehyde) in Xi'an Jiaotong University and Heihe was estimated (8.82 × 10(-5) and 4.96 × 10(-5), respectively). This study provides a clear map on the abundances of carbonyls and their source interpretation in the largest and the most economic city in Northwestern China.

Estimation of exhaust emission from ocean-going vessels in Hong Kong

As one of the busiest port in the world, ship emissions have become of great concern in Hong Kong. In this study, a detailed maritime emission inventory for ocean-going vessels (OGVs) in Hong Kong with the base year of 2007 was developed. The high-resolution vessel speed profiles determined using the Automatic Identification System (AIS) during 2009 were adopted for the speed data in the estimation. It was obtained that the total ship emissions from 37,150 voyages of OGVs in 2007 were 17,097, 8190, and 1035 tonnes accounting for 17%, 11%, and 16% of the total emissions of NO(x), SO(2), and PM(10), respectively. The contribution of ship emissions during transiting was 60-68% for three pollutants while the emissions during hotelling were responsible for the remaining portions. From the emission spatial allocation, the shipping route along the East Lamma Channel and the berthing location of the Kwai Chung and Tsing Yi Container Port comprised the regions with the highest emissions. The OGV emissions in Hong Kong contributed 0.07% NO(x), 0.05% SO(2), and 0.06% PM(10) out of the global total shipping emissions in 2007.

Characteristics and source apportionment of PM1 emissions at a roadside station

The mass concentrations of PM(1) (particles less than 1.0 μm in aerodynamic diameter), organic carbon (OC), elemental carbon (EC), water-soluble ions, and up to 25 elements were reported for 24h aerosol samples collected every sixth day at a roadside sampling station in Hong Kong from October 2004 to September 2005. Annual average PM(1) mass concentration was 44.5 ± 19.5 μg m(-3). EC, OM (organic matter, OC × 1.2), and SO(4)(=) were the dominant components, accounting for ∼ 36%, ∼ 26%, and ∼ 24% of PM(1), respectively. Other components, i.e., NO(3)(-), NH(4)(+), geological material, trace elements and unidentified material, comprised the remaining ∼ 14%. Annual average OC/EC ratio (0.6 ± 0.3) was low, indicating that primary vehicle exhaust was the major source of carbonaceous aerosols. The seasonal variations of pollutants were due to gas-particle partitioning processes or a change in air mass rather than secondary aerosol produced locally. Vehicle exhaust, secondary aerosols, and waste incinerator/biomass burning were dominant air pollution sources, accounting for ∼ 38%, ∼ 22% and ∼ 16% of PM(1), respectively. Pollution episodes during summer (May-August) which were frequently accompanied by tropical storms or typhoons were dominated by vehicle emissions. During winter (November-February) pollution episodes coincided with northeasterly monsoons were characterized by secondary aerosols and incinerator/biomass burning emissions.

Comparison of patient-reported late treatment toxicity (LENT-SOMA) with quality of life (EORTC QLQ-C30 and QLQ-H&N35) assessment after head and neck radiotherapy

PURPOSE

The patient's role in toxicity reporting is increasingly acknowledged but requires the adaptation and validation of toxicity reporting instruments for patient use as most toxicity scales are designed for physician use. Recording of radiotherapy related late toxicity is important and needs to be improved. A patient-scored symptom questionnaire of late treatment effects using LENT-SOMA was compared with a recognised quality of life tool (EORTC QLQ-C30/H&N35).

MATERIALS/METHODS

LENT-SOMA and EORTC QLQ-C30 patient questionnaires were prospectively completed by 220 head and neck cancer patients over 3 years and 72 completed EORTC QLQ-H&N35 questionnaires at 2 years post-radiotherapy.

RESULTS

Endpoints common to both questionnaires (pain, swallowing, dental pain, dry mouth, opening mouth, analgesics) were matched. Spearman rank correlation coefficients with ρ>0.6 (P<0.001) were obtained for all "matched" scales except for analgesics scale, ρ=0.267 (P<0.05). There was good agreement between LENT-SOMA and EORTC QLQ-H&N35 except for analgesic endpoints. Global quality of life scores correlated negatively with average LENT-SOMA scores (P<0.001). Significant differences in average LENT-SOMA scores between treatment modalities were found. The LENT-SOMA questionnaire has demonstrated a high Cronbach's α value (0.786) indicating good reliability.

CONCLUSIONS

LENT-SOMA patient questionnaire results agreed well with those from the EORTC QLQ-H&N35 questionnaire for toxicity items where they could be compared explicitly, particularly for subjective endpoints. Patient-reported late toxicity had a negative impact on quality of life. The LENT-SOMA patient questionnaire is both reliable and sensitive to differences between patients treated with different modalities. A patient-based questionnaire is an important contributor to capturing late radiotherapy effects.

On the relationship between ozone and its precursors in the Pearl River Delta: application of an observation-based model (OBM)

BACKGROUND, AIM, AND SCOPE

Photochemical smog, characterized by high concentrations of O(3) and fine particles, is of great concern in the urban areas, in particular megacities and city clusters like the Pearl River Delta.

MATERIALS, METHODS, AND RESULTS

Ambient ozone (O(3)) and its precursors were simultaneously measured at two sites in the Pearl River Delta, namely, Wan Qing Sha (WQS) in Guangzhou and Tung Chung (TC) in Hong Kong, from 23 October to 01 December 2007 in order to explore their potential relationship. Eight high O(3) episode days were identified at WQS and two at TC during the sampling campaign, indicating a more serious O(3) pollution in Guangzhou than in Hong Kong. An observation-based model was employed to determine the ozone-precursor relationship. At both sites, O(3) production was found to be volatile organic compound (VOC)-limited, which is consistent with previous observations. Anthropogenic hydrocarbons played a key role in O(3) production, while reducing nitric oxide emissions aided the buildup of O(3) concentrations. Among VOC species, the summed relative incremental reactivity (RIR) of the top 12 compounds accounted for 89% and 85% of the total RIR at WQS and TC, respectively, indicating that local photochemical O(3) formation can be mainly attributed to a small number of VOC species.

DISCUSSION AND CONCLUSIONS

A large increment in both simulated HO(2) and O(3) concentrations was achieved with additional input of hourly carbonyl data. This suggested that apart from hydrocarbons, carbonyls might significantly contribute to the O(3) production in the Pearl River Delta.

Chemically-speciated on-road PM(2.5) motor vehicle emission factors in Hong Kong

PM(2.5) (particle with an aerodynamic diameter less than 2.5microm) was measured in different microenvironments of Hong Kong (including one urban tunnel, one Hong Kong/Mainland boundary roadside site, two urban roadside sites, and one urban ambient site) in 2003. The concentrations of organic carbon (OC), elemental carbon (EC), water-soluble ions, and up to 40 elements (Na to U) were determined. The average PM(2.5) mass concentrations were 229+/-90, 129+/-95, 69+/-12, 49+/-18microg m(-3) in the urban tunnel, cross boundary roadside, urban roadside, and urban ambient environments, respectively. Carbonaceous particles (sum of organic material [OM] and EC) were the dominant constituents, on average, accounting for approximately 82% of PM(2.5) emissions in the tunnel, approximately 70% at the three roadside sites, and approximately 48% at the ambient site, respectively. The OC/EC ratios were 0.6+/-0.2 and 0.8+/-0.1 at the tunnel and roadside sites, respectively, suggesting carbonaceous aerosols were mainly from vehicle exhausts. Higher OC/EC ratio (1.9+/-0.7) occurred at the ambient site, indicating contributions from secondary organic aerosols. The PM(2.5) emission factor for on-road diesel-fueled vehicles in the urban area of Hong Kong was 257+/-31mg veh(-1) km(-1), with a composition of approximately 51% EC, approximately 26% OC, and approximately 9% SO(4)(=). The other inorganic ions and elements made up approximately 11% of the total PM(2.5) emissions. OC composed the largest fraction (approximately 51%) in gasoline and liquid petroleum gas (LPG) emissions, followed by EC (approximately 19%). Diesel engines showed higher emission rates than did gasoline and LPG engines for most pollutants, except for V, Br, Sb, and Ba.

Predictions of gas-particle partitioning coefficients (K(P)) of polycyclic aromatic hydrocarbons at various occupational environments of Songkhla Province, Thailand

Ambient air samples were collected over periods of 24 hours and 3 hours using a Graseby-Anderson high volume air sampler with PM10 TE-6001 at 15 sampling sites, including an urban residential zone, rural area, industrial factories, waste incinerator, traffic areas and agricultural burning areas in Songkhla Province, Thailand. An analysis of organic carbon and elemental carbon was conducted to estimate the gas-particle partitioning of PAHs using a model proposed by Dachs-Eisenreich. The estimated LogK(P) of PAHs emphasized the risk for lung cancer among outdoor workers in waste incinerators, traffic intersections and bus terminals, suggesting the role of the carbonaceous fraction over the gas-particle partitioning of PAHs. Analysis of f(SC)K(SA)delta(OCT)/F(OM)K(OA) ratios revealed a significant role of adsorption and absorption in unusually high elemental carbon fractions (ie low OC/EC ratio) in fine particles collected at waste incinerators and the abnormally high organic carbon fractions (ie high OC/EC ratio) observed in those fine particles of an urban residential zone, respectively. The dual mode of ab/adsorption tended to dominate the gas-particle partitioning of LMW PAHs collected at the traffic intersections and bus terminal.

Developing a CTCAEs patient questionnaire for late toxicity after head and neck radiotherapy

PURPOSE

Patient-based reporting of symptoms is increasingly important in providing treatment toxicity information. However, observer-based scoring systems such as the CTCAEs which incorporate the LENT-SOMA scales are not adapted for patient-based reporting. We aim to (1) report the late toxicity in patients following head and neck radiotherapy using a LENT-SOMA patient-based questionnaire, (2) describe how the responses help to improve the questionnaire and (3) adapt the questionnaire for patient reporting using CTCAEs.

METHODS

A 31-item LENT-SOMA patient questionnaire was administered prospectively to 220 patients pre-treatment and at eight time periods post-radical head and neck radiotherapy over 3 years. Exploratory factor analysis was carried out and questionnaire reliability was evaluated using Cronbach's alpha coefficient.

RESULTS

At 3-years follow-up, grade 3/4 toxicity was recorded for xerostomia (44%), hoarseness (14.3%), altered taste (6.1%) and oropharyngeal pain (1.9%). Factor analysis indicated that questionnaire division according to anatomical sub-site was reasonable. Cronbach's alpha was 0.851 (95% CI: 0.820-0.883) indicating high reliability. Good compliance was obtained with all questions except for the 'weight loss' item. A satisfaction survey showed that the questionnaire was clear and concise. Teeth and mandible sections have been removed. Dietary change due to xerostomia has been incorporated in line with CTCAEs. LENT-SOMA scoring of analgesic needs and dysphagia not described in CTCAEs were found useful and have been retained.

CONCLUSIONS

The questionnaire has enabled reporting of late toxicity and the responses have enabled refinement of the questionnaire. It is reliable, feasible and has been validated for patient-based collection of CTCAEs late toxicity data.

Characteristics of emissions of air pollutants from burning of incense in temples, Hong Kong

Field investigations of target air pollutants at two of the most famous temples in Hong Kong were conducted. The air pollution problems in these two temples during peak and non-peak periods were characterized. The target air pollutants included particulate matters (PM(10), PM(2.5)), volatile organic compounds (VOCs), carbonyl compounds, carbon monoxide (CO), nitrogen oxides (NO(x)), methane (CH(4)), non-methane hydrocarbons (NMHC), organic carbon (OC), elemental carbon (EC), and inorganic ions (Cl(-), NO(3)(-), SO(4)(2-), Na(+), NH(4)(+), and K(+)). The pollutant levels of the two temples during peak period were shown to be significantly higher than those during non-peak period. The highest average CO level was obtained at Temple 1 during peak period, which exceeded IAQO 8-h Good Class criteria. In general, the average PM(2.5)/PM(10) ratios were approximately 82%. The results revealed that the fine particulates (PM(2.5)) constituted the majority of suspended particulates at both temples. It was noted that formaldehyde was the most abundant carbonyl compounds, followed by acetaldehyde. At Temple 1 during peak period, the average benzene concentration exceeded almost 8 times more than Indoor Air Quality Objectives for Office Buildings and Public Places (IAQO) [HKEPD, 2003. Guidance notes for the management of indoor air quality in offices and public places. Indoor air quality management group, The Government of the Hong Kong Special Administrative Region.] Good Class criteria. The average OC/EC ratios ranged from 2.6 to 17 in PM(10) and from 4.2 to 18 in PM(2.5) at two temples, which suggested that OC measured in these two temple areas may be due to both direct emission from incense burning and secondary formation by chemical reactions. The total mass of inorganic ions, organic carbon, and elemental carbon accounted for about 71% in PM(2.5) and 72% in PM(10).

Source apportionment of PM2.5 in urban area of Hong Kong

A monitoring program for PM(2.5) had been performed at two urban monitoring stations in Hong Kong from November 2000 to February 2001 and June 2001 to August 2001. PM(2.5) samples were collected once every 6 days at PolyU and KT stations with the sampling duration of 24-h. A sum of 25 chemical species in PM(2.5) were determined and selected for receptor models. Enrichment factors relative to earth crust abundances were evaluated and it was noted that most crustal elements including Al, Ti, Mg, Ca and K have small enrichment factors. Correlation and multivariate analysis technique, such as principal components analysis (PCA)/absolute principal components analysis (APCA) and cluster analysis (CA) are used for source apportionment to identify the possible sources of PM(2.5) and to determine their contribution. Six factors at each site were isolated by using PCA/APCA and cluster analysis. Similar sources (crustal matter, automobile emission, diesel emission, secondary aerosols, tire wear, and non-ferrous smelter) are identified by the PCA/APCA and cluster analysis.

Low molecular weight dicarboxylic acids, ketoacids, and dicarbonyls in the fine particles from a roadway tunnel: possible secondary production from the precursors

Low molecular weight dicarboxylic acids (DCAs), ketoacids, and alpha-dicarbonyls have been determined for the PM2.5 samples in a Hong Kong roadway tunnel, using a water extraction followed by a butyl ester and/or dibutyl acetal derivatization technique. For the most wintertime sampling runs, outlet and inlet concentrations of the quantified compounds were found to be quite similar (ca. 10% differences), leading to the conclusion that direct emissions of the organic compounds are insignificant from vehicles in hot-stabilized operations although vehicular emissions can provide important precursors to them. In contrast, a significant concentration increase of most compounds was observed at the outlet station compared to the inlet station in the summertime runs, which might be explained by the secondary production of aerosols in the tunnel. The organic compounds studied comprised a small fraction (<1%) of aerosol organic carbon (OC). In winter, their abundances relative to that of OC in outlet samples were found to be significantly less than those in inlet samples. On the basis of the summer data, apparent secondary production factors of the compounds were calculated, which indicate that adipic and m-phthalic acids can be favorably formed in the tunnel. However, like other DCAs, direct emissions of adipic, m-phthalic, and p-phthalic acids from automobiles are suggested to be insignificant.

Carbonyl compounds in the roadside environment of Hong Kong

The levels of carbonyl compounds were determined at the roadside urban station at the Hong Kong Polytechnic University (HKPU) campus during January 2002 to February 2002. Nine carbonyl compounds were quantified in this study. Temperature and solar radiation were found to affect the photochemical reactions of the carbonyls. Formaldehyde/acetaldehyde ratio ranged from 1.27 to 1.35. Strong correlations between formaldehyde and acetaldehyde were found, in the time period 1800-2100, which indicated that they were originated from the same sources during this time period. Roadside carbonyl samples were also collected at four other roadside environments during 2001. Kwai Chung (KC) station showed the highest average formaldehyde and acetaldehyde concentrations due to its highest traffic flow, especially for diesel vehicles. High concentration of toluene emitted from gasoline-fueled vehicles was believed to be the cause of high benzaldehyde level at the Central (CT) station through the photochemical oxidation of toluene. The average concentrations of formaldehyde and acetaldehyde in Hong Kong are well within the ranges reported in roadside environments of other urban cities. However, Mexico City in Mexico and Cairo in Egypt had much higher concentration levels of formaldehyde and acetaldehyde than in Hong Kong roadside environment due to the incomplete combustion of different fuel compositions.

Seasonal variations and mass closure analysis of particulate matter in Hong Kong

The chemical characteristics of ambient particulate matters in urban and rural areas of Hong Kong were determined in this study. A monitoring program starting from November 2000 to February 2001 (winter) and June 2001 to August 2001 (summer) for PM10 and PM2.5 was performed at three monitoring stations in Hong Kong. Twenty-four-hour PM10 and PM2.5 samples were collected once every 6 days at two urban sites, PolyU and KT, and every 12 days at a background site, HT, with Hi-Vol samplers. High concentrations of OC, EC (except in PolyU), water-soluble ions and elements were observed in winter among the three sampling sites for PM10 and PM2.5 fractions. Seasonal variations were significant in background HT. Dilution effect due to the increase in mixing depth and precipitation in summer reduced the concentrations of particulate matters. Long-range transport could contribute to the higher concentrations of particulate matter in the winter. Chemical mass closure calculations were performed for PM10 and PM2.5 observed. Mass closure improved when separate factors (1.4 and 1.9 respectively) were used to convert water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WINSOC) into corresponding organic masses. The urban sites showed high percentages of water-soluble ions in winter and high percentages of carbonaceous species in summer. Better results were obtained for the chemical mass closure analysis in winter than in summer. High temperature and solar radiation in summer increased the rate of the complex photochemical reaction in the atmosphere. Therefore the chemical mass closure analysis would underestimate the volatized species and secondary aerosols during summer.

Pathological complete response following pre-operative chemoradiotherapy in rectal cancer: analysis of phase II/III trials

Pathological complete response (pCR) has been used as a marker for the efficacy of pre-operative chemoradiotherapy (CRT) schedules in rectal cancer. To date there have been no randomized trials comparing CRT regimens in rectal cancer. Prospective phase II and CRT arms of randomized trials reported up to January 2004 were included, providing they defined the following minimum variables: drugs employed during CRT, radiotherapy dose and pCR rate. Multivariate analysis was used to examine the relationship of these variables on the pCR rate. In addition, the use of neoadjuvant chemotherapy, the type of publication (peer reviewed vs meeting abstract) and whether the tumours were stated to be unresectable/clinically fixed or to have threatened circumferential margins were investigated. The method of analysis was weighted linear modelling of the pCR rate which was normalized by the arcsine transformation. Phase II and phase III trials were identified including a total of 3157 patients. On multivariate analysis only the use of continuous infusion 5FU (p = 0.01), the use of a second drug (p = 0.001) and radiation dose (p = 0.02) were associated with higher rates of pCR. The use of a two drug regimen, the mode of delivery of 5FU and the radiation dose appear to be related to the incidence of pCR following CRT for rectal cancer. These results may generate hypotheses for future randomized trials. Important factors not considered in this analysis include the variability in pathological examination and in the time interval between CRT and surgery. In addition, the toxicity of the CRT regimens requires further investigation.

Indoor/outdoor relationships for PM2.5 and associated carbonaceous pollutants at residential homes in Hong Kong - case study

Six residences were selected (two roadside, two urban, and two rural) to evaluate the indoor-outdoor characteristics of PM(2.5) (aerodynamic diameter <2.5 microm) carbonaceous species in Hong Kong during March and April 2004. Twenty-minute-averaged indoor and outdoor PM(2.5) concentrations were recorded by DustTrak samplers simultaneously at each site for 3 days to examine diurnal variability of PM(2.5) mass concentrations and their indoor-to-outdoor (I/O) ratios. Daily (24-h average) indoor/outdoor PM(2.5) samples were collected on pre-fired quartz-fiber filters with battery-powered portable mini-volume samplers and analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance (TOR) following the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. The average indoor and outdoor concentrations of 24 h PM(2.5) were 56.7 and 43.8 microg/m(3), respectively. The short-term PM(2.5) profiles indicated that the penetration of outdoor particles was an important contributor to indoor PM(2.5), and a household survey indicated that daily activities were also sources of episodic peaks in indoor PM(2.5). The average indoor OC and EC concentrations of 17.1 and 2.8 microg/m(3), respectively, accounted for an average of 29.5 and 5.2%, respectively, of indoor PM(2.5) mass. The average indoor OC/EC ratios were 5.8, 9.1, and 5.0 in roadside, urban, and rural areas, respectively; while average outdoor OC/EC ratios were 4.0, 4.3, and 4.0, respectively. The average I/O ratios of 24 h PM(2.5), OC, and EC were 1.4, 1.8, and 1.2, respectively. High indoor-outdoor correlations (r(2)) were found for PM(2.5) EC (0.96) and mass (0.81), and low correlations were found for OC (0.55), indicative of different organic carbon sources indoors. A simple model implied that about two-thirds of carbonaceous particles in indoor air are originated from outdoor sources.

PRACTICAL IMPLICATIONS

Indoor particulate pollution has received more attentions in Asia. This study presents a case study regarding the fine particulate matter and its carbonaceous compositions at six residential homes in Hong Kong. The characteristics and relationship of atmospheric organic and elemental carbon were discussed indoors and outdoors. The distribution of eight carbon fractions was first reported in indoor samples to interpret potential sources of indoor carbonaceous particles. The data set can provide significant scientific basis for indoor air quality and epidemiology study in Hong Kong and China.

Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong

Ambient air quality measurements of 156 species including 39 alkanes, 32 alkenes, 2 alkynes, 24 aromatic hydrocarbons, 43 halocarbons and 16 carbonyls, were carried out for 120 air samples collected at two sampling stations (CW and TW) in 2001 throughout Hong Kong. Spatial variations of volatile organic compounds (VOCs) in the atmosphere were investigated. Levels of most alkanes and alkenes at TW site were higher than that at the CW site, while the BTEX concentrations at the two sites were close. The BTEX ratios at CW and TW were 1.6:10.1:1.0:1.6 and 2.1:10.8:1.0:2.0, respectively. For major halogenated hydrocarbons, the mean concentrations of chloromethane, CFCs 12 and 22 did not show spatial variations at the two sites. However, site-specific differences were observed for trichloroethene and tetrachloroethene. Furthermore, there were no significant differences for carbonyls such as formaldehyde, acetaldehyde and acetone between the two sites. The levels of selected hydrocarbons in winter were 1-5 times that in summer. There were no common seasonal trends for carbonyls in Hong Kong. The ambient level of formaldehyde, the most abundant carbonyl, was higher in summer. However, levels of acetaldehyde, acetone and benzaldehyde in winter were 1.6-3.8 times that in summer. The levels of CFCs 11 and 12, and chloromethane in summer were higher than that in winter. Strong correlation of most hydrocarbons with propene and n-butane suggested that the primary contributors of hydrocarbons were vehicular emissions in Hong Kong. In addition, gasoline evaporation, use of solvents, leakage of liquefied petroleum gas (LPG), natural gas leakage and other industrial emissions, and even biogenic emissions affected the ambient levels of hydrocarbons. The sources of halocarbons were mainly materials used in industrial processes and as solvents. Correlation analysis suggested that photochemical reactions made significant contributions to the ambient levels of carbonyls in summer whereas in winter motor vehicle emissions would be the major sources of the carbonyls. The photochemical reactivity of selected VOCs was estimated in this study. The largest contributors to ozone formation were formaldehyde, toluene, propene, m,p-xylene, acetaldehyde, 1-butene/i-butene, isoprene and n-butane, suggesting that motor vehicles, gasoline evaporation, use of solvents, leakage of LPG, photochemical processes and biogenic emission are sources in the production of ozone. On the other hand, VOCs from vehicles and gasoline evaporation were predominant with respect to reactions with OH radical.

Seasonal and diurnal variations of volatile organic compounds (VOCs) in the atmosphere of Hong Kong

Ambient VOCs samples were collected at three locations (PolyU campus (PU), Kwun Tong (KT), Hok Tsui (HT)) in Hong Kong during the periods of November 2000-February 2001 and June 2001-August 2001. Also the concentrations of VOCs in Cross Harbor tunnel in Hong Kong were obtained in order to determine the vehicular sources of VOCs. Toluene was the most abundant VOC detected in Hong Kong. At the PU station, which is close to a main road, the concentrations of most VOCs were higher in summer than in winter. However, at the background location HT, the concentrations of all VOCs except tetrachloroethene were higher in winter than in summer. Regional physical dispersion/transportation and mixing depth may be the reasons for higher VOC concentrations in winter at HT. The BTEX (benzene:toluene:ethylbenzene:xylene) ratios of PU and KT during winter period were (1.9:10.1:1.0:1.8) and (1.9:10.4:1.0:1.5), and (0.9:8.3:1.0:2.2) and (0.8:29.6:1.0:1.8) for summer season, respectively. The xylene/ethylbenzene (X/E) ratio was used to assess the relative age of the air parcels in this study. The concentrations of VOCs in the atmosphere in Hong Kong were mainly affected by direct emissions from vehicles, evaporation of fuels, photochemical reactions and few industrial emissions. The BTEX ratio in the tunnel was 2:10.4:1:3.2. The BTEX ratios at PU and KT during the winter period were similar to that in tunnel (except for xylenes). The X/E ratio in the tunnel was higher than that in the ambient air. This indicated that the freshly emitted xylenes in the tunnel decayed at different rates from OH-oxidation in the atmosphere. Good BTEX correlations (r>0.8) were found at PU and KT in winter (**P<0.01). Vehicular exhaust was the dominant source at PU and KT stations, and less evaporation of fuel or additive occurred at low temperature in winter. Diurnal variations of mean BTEX concentrations at the roadside monitoring station (PU) showed two peaks associated with traffic density and vehicle type.

Characterization of ambient volatile organic compounds at a landfill site in Guangzhou, South China

Ambient air monitoring was conducted at Datianshan landfill, Guangzhou, South China in 1998 to investigate the seasonal and horizontal variations of trace volatile organic compounds (VOCs). Twelve sampling points over the Datianshan landfill were selected and samples were collected simultaneously using Carbontrap(TM) adsorption tubes. Thirty eight VOCs were detected in the winter, whereas 60 were detected in the summer. The VOC levels measured in summer were alkanes, 0.5-6.5 microg/m(3); aromatics, 2.3-1667 microg/m(3); chlorinated species, 0.2-31 microg/m(3); terpines, 0.1-34 microg/m(3); carbonyl species, 0.3-5.6 microg/m(3) and naphthalene and its derivatives, 0.4-27 microg/m(3). Compared to the summer samples the VOC levels in winter were much lower (mostly 1-2 orders of magnitude lower). The aromatics are dominant VOCs in landfill air both in winter and summer. High levels of alkylbenzene and terpines such as methyl-isopropylbenzene (max 1667 microg/m(3)) and limonene (max 162 microg/m(3)) cause undesirable odor. The similar correlation coefficients of BTEX in summer and winter suggest VOCs emissions were from landfill site sources. The variation of BTEX ratio at landfill site is different from that in the urban area of Guangzhou. It shows that the ambient VOCs at landfill site were different from the urban areas.

Carbonaceous characteristics of atmospheric particulate matter in Hong Kong

To determine the characteristic of carbonaceous species in atmospheric particles in Hong Kong, PM10 and PM2.5 samples were collected using high volume (hi-vol.) air samplers from November 2000 to February 2001. The organic carbon (OC) and elemental carbon (EC) were analyzed by the selective thermal manganese dioxide oxidation (TMO) method. The ratios of PM2.5/PM10 mass ratios were 0.61, 0.78 and 0.53 for particulate matter collected at PolyU station (PolyU, near a major traffic corridor), Kwun Tong station (KT, mixed residential/commercial/industrial) and the Hok Tsui background station (HT), respectively. These results indicate that the PM2.5 concentrations constitute the majority of the PM10) concentrations, especially in urban and industrial areas of Hong Kong. The average concentrations at the three sites ranged from 73.11 to 83.52 microg/m3 for PM10 and from 42.37 to 57.38 microg/m3 for PM2.5. The highest daily mass concentrations of PM10 and PM2.5 were 125.89 microg/m3 and 116.89 microg/m3 at KT, respectively. The correlation between PM10 and PM2.5 was high at KT and HT (r > 0.9, P < 0.01). This means that the sources of PM10 and PM2.5 may be the same at both sites. The highest mean concentration of OC (12.02 microg/m3) and EC (6.86 microg/m3) in PM10 was found at the PolyU among the three sites. For PM2.5, the highest mean concentration of OC (10.16 microg/m3) was at KT while the highest mean concentration of EC (7.95 microg/m3) was at PolyU. However, the background concentrations at HT were higher than another background area, Kosan, Korea. Transportation of pollutants from the Asian continent may be responsible for the elevations of EC+ OC at the remote site. More than 74% of the EC and more than 79% of the OC were found in the PM2.5 fraction at the three sampling locations. At PolyU station, PM2.5 consisted of 18.18% OC and 11.16% EC while 17.70% OC and 8.81% EC were found in KT station. Thus OC and EC are major constituents of aerosols in Hong Kong. OC/EC ratios for PM10 and PM2.5 were less than 2 at PolyU and KT stations while the ratio exceeded 3 at HT background station. This indicates that OC measured in the urban area may be emitted directly as a primary aerosol.

Volatile organic compounds (VOCs) in urban atmosphere of Hong Kong

The assessment of volatile organic compounds (VOCs) has become a major issue of air quality network monitoring in Hong Kong. This study is aimed to identify, quantify and characterize volatile organic compounds (VOCs) in different urban areas in Hong Kong. The spatial distribution, temporal variation as well as correlations of VOCs at five roadside sampling sites were discussed. Twelve VOCs were routinely detected in urban areas (Mong Kok, Kwai Chung, Yuen Long and Causeway Bay). The concentrations of VOCs ranged from undetectable to 1396 microg/m3. Among all of the VOC species, toluene has the highest concentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) were the major constituents (more than 60% in composition of total VOC detected), mainly contributed from mobile sources. Similar to other Asian cities, the VOC levels measured in urban areas in Hong Kong were affected both by automobile exhaust and industrial emissions. High toluene to benzene ratios (average T/B ratio = 5) was also found in Hong Kong as in other Asian cities. In general, VOC concentrations in the winter were higher than those measured in the summer (winter to summer ratio > 1). As toluene and benzene were the major pollutants from vehicle exhausts, there is a necessity to tighten automobile emission standards in Hong Kong.

Identification of atmospheric volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds in Hong Kong

Volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and carbonyl compounds are the major organic pollutants in the atmosphere. Emissions from motor vehicles have been one of the primary pollution sources in the metropolitan area of Hong Kong. A 12-month monitoring program for VOCs, PAHs and carbonyl compounds was performed at a roadside urban station at Hong Kong Polytechnic University (HKPU) in order to determine the correlations of each selected pollutant. The monitoring program ran from 16 April 1999 to 10 April 2000 for a period of 1 year, and a 2-week winter intensive sampling was carried out during January 2000. Traditionally, emission sources are identified from organic compounds in air particulates. Since many of the gaseous and particulate phases of organic compounds are from the same sources, correlations between the major exhausts are to be expected. Therefore, it would be more effective to apportion the sources using the combined gaseous and particulate phases of organic compounds. Correlations of selected pollutants within two other toxic air pollutants (TAPs) monitoring stations in Tsuen Wan (TW) and Central/Western (CW) were analyzed. Good correlations were found between pollutants that came from vehicle exhaust, especially in intensive sampling periods at HKPU roadside station. This was because the washing out effect for particulates during rainy days and photochemical degradation during high solar radiation were minimized in wintertime.

Determination of lead in fine particulates by slurry sampling electrothermal atomic absorption spectrometry

A simple method for determining lead in fine particulates (PM2.5) by using electrothermal atomic absorption spectrometry (ETAAS) has been developed. Particulates collected on Nuclepore filter by using a dichotomous sampler were suspended in diluted nitric acid after ultrasonic agitation. The dislodging efficiency is nearly 100% after agitation for 5 min. In order to study the suspension behavior of PM2.5 in solvents, a Brookhaven ZetaPlus Particle Size Analyzer was used to determine the particle size distribution and suspension behavior of air particulates in the solvent. The pre-digestion and modification effect of nitric acid would be discussed. Palladium was added as a chemical modifier and the temperature program of ETAAS was changed in order to improve the recovery. The slurry was introduced directly into a graphite tube for atomization. The metal content in the sample was determined by the standard addition method. In addition, a conventional acid digestion procedure was applied to verify the efficiency of the slurry sampling method. It offers a quick and efficient alternative method for heavy metal characterization in fine particulates.

Direct ultrasonic agitation for rapid extraction of organic matter from airborne particulate

Direct ultrasonic extraction (DUE) is proposed as simple and rapid sample pretreatment method. This new approach is applied to the extraction of particulate organic matter (POM) from airborne particulate by using dichloromethane (DCM) or DCM/methanol (90/10, v/v) as extractant. The analytical determination was carried out by weighing the extractable POM on an electrobalance. Total recovery for POM could be obtained when the sample was extracted three times with 25-50 mL extractant each for about 5 min at 50 W ultrasonic power. In comparison with conventional Soxhlet extraction, less extraction time (total 15 min only) and solvent consumption (100 mL) were required by DUE. The efficiency of the DUE was similar or even higher than the routine Soxhlet method. Additionally, the new extractor is very simple and easy to use and can accelerate the extraction procedures of organic components from various solid samples.

Phylogenetic analysis of DNA length mutations in a repetitive region of the Hawaiian Drosophila yolk protein gene Yp2

Nucleotide sequence analysis has demonstrated that interspecific size variation in the YP2 yolk protein among Hawaiian Drosophila is due to in-frame insertions and deletions in two repetitive segments of the coding region of the Yp2 gene. Sequence comparisons of the complex repetitive region close to the 5' end of this gene across 34 endemic Hawaiian taxa revealed five length morphs, spanning a length difference of 21 nucleotides (nt). A phylogenetic character reconstruction of the length mutations on an independently derived molecular phylogeny showed clade-specific length variants arising from six ancient events: two identical insertions of 6 nt, and four deletions, one of 6 nt, one of 12 nt, and two identical but independent deletions of 15 nt. These mutations can be attributed to replication slippage with nontandem trinucleotide repeats playing a major role in the slipped-strand mispairing. Geographic analysis suggests that the 15 nt deletion which distinguishes the planitibia subgroup from the cyrtoloma subgroup occurred on Oahu about 3 million years ago. The homoplasies observed caution against relying too heavily on nucleotide insertions/deletions for phylogenetic inference. In contrast to the extensive repeat polymorphisms within other Drosophila and the human species, the more complex 5' Yp2 repetitive region analyzed here appears to lack polymorphism among Hawaiian Drosophila, perhaps due to founder effects, low population sizes, and hitchhiking effects of selection on the immediately adjacent 5' region.

Pattern of ecological shifts in the diversification of Hawaiian Drosophila inferred from a molecular phylogeny

BACKGROUND

The endemic Hawaiian drosophilids, a unique group that are remarkable for their diversity and rapid proliferation, provide a model for analysis of the process of insular speciation. Founder events and accompanying random drift, together with shifts in sexual selection, appear to explain the dramatic divergence in male morphology and mating behaviour among these flies, but these forces do not account for their spectacular ecological diversification into a wide array of breeding niches. Although recognized as contributing to the success of this group, the precise role of adaptive shifts has not been well defined.

RESULTS

To delineate the pattern of ecological diversification in the evolution of Hawaiian Drosophila, we generated a molecular phylogeny, using nucleotide sequences from the yolk protein gene Yp1, of 42 endemic Hawaiian and 5 continental species. By mapping ecological characters onto this phylogeny, we demonstrate that monophagy is the primitive condition, and that decaying leaves were the initial substrate for oviposition and larval development. Shifts to decaying stems, bark and tree fluxes followed in more derived species. By plotting female reproductive strategies, as reflected in ovarian developmental type, on the molecular tree, we also demonstrate a phylogenetic trend toward increasing fecundity. We find some statistical support for correlations between ecological shifts and shifts in female reproductive strategies.

CONCLUSIONS

Because of the short branches at the base of the phylogram, which lead to ecologically diverse lineages, we conclude that much of the adaptive radiation into alternate breeding substrates occurred rapidly, early in the group's evolution in Hawaii. Furthermore, we conclude that this ecological divergence and the correlated changes in ovarian patterns that adapt species to their ecological habitats were contributing factors in the major phyletic branching within the Hawaiian drosophilid fauna.

Sodium hyaluronate use during lens expression in extracapsular cataract surgery in rabbits

Albino rabbits were used to compare the effects of filling the anterior chamber with balanced salt solution or sodium hyaluronate prior to lens expression in an extracapsular surgical technique. No significant differences were found between the two utilizing periodic slit lamp examinations, measurements of intraocular pressure, corneal thickness or corneal endothelial cell density. Sodium hyaluronate maintained a deeper anterior chamber and simplified lens expression.