Changes in Polychlorinated Biphenyl Residues in Milk during Lactation: Levels of Contamination, Influencing Factors, and Infant Risk Assessment.

Given the importance of breastfeeding infants, the contamination of human milk is a significant public concern. The aim of this study was to assess the contamination of human milk with dioxin-like PCBs (dl-PCBs) and non-dioxin-like PCBs (ndl-PCBs) in relation to the duration of lactation and other influencing factors, especially the frequency of the consumption of selected foods during pregnancy. Based on this, the health risk to infants was assessed and compared to the tolerable daily intake (TDI). PCB determinations were performed using gas chromatography/mass spectrometry. The ∑ndl-PCB content ranged from 0.008 to 0.897 ng/g w.w., at an average of 0.552 ng/g wet weight, which was 55% of the maximum level according to the EU guidelines for foods for infants and young children. The toxic equivalent (TEQ) was in the range of 0.033-5.67 pg-TEQ/g w.w. The content of non-ortho, mono-ortho, and ndl-PCBs in human milk decreased the longer lactation continued. Moreover, when pregnant women smoked tobacco, this correlated significantly with increases in the concentrations of PCB congeners 156, 118, and 189 in human milk. The human milk contents of PCB congeners 77, 81, 186, 118, and 189 were strongly positively correlated with the amount of fish consumed. The content of stable congeners PCB 135 and PCB 153 increased with age.

Short and Atom-Economic Enantioselective Synthesis of the σ1-Receptor Ligands (S)- and (R)-Fluspidine-Important Tools for Positron Emission Tomography Studies.

Aryl bromides 2a and 2b bearing an alkynyl substituent in the o-position reacted with n-butyllithium and 1-benzylpiperidin-4-one in a one-pot Domino reaction to form ester 3 and aldehyde 5, respectively. Enantiomeric alcohols (R)-8 and (S)-8 were obtained by conjugate NaBH4 reduction of α,ß-unsaturated ester 3 in the presence of chiral cocomplexes (R,R)-10 and (S,S)-10. Starting from orthoester 2a, the precursors (R)-8 and (S)-8 for the synthesis of fluspidine enantiomers (R)-1/[18F](R)-1 and (S)-1/[18F](S)-1 were obtained in only two reaction steps without additional steps for N-protection in an atom-economic manner in 95.6% ee and 97.2% ee, respectively.

Molecular dynamics simulation and binding free energy studies of novel leads belonging to the benzofuran class inhibitors of Mycobacterium tuberculosis Polyketide Synthase 13.

In this work, the binding mechanism of new Polyketide Synthase 13 (Pks13) inhibitors has been studied through molecular dynamics simulation and free energy calculations. The drug Tam1 and its analogs, belonging to the benzofuran class, were submitted to 100 ns simulations, and according to the results obtained for root mean square deviation, all the simulations converged from approximately 30 ns. For the analysis of backbone flotation, the root mean square fluctuations were plotted for the Cα atoms; analysis revealed that the greatest fluctuation occurred in the residues that are part of the protein lid domain. The binding free energy value (ΔGbind) obtained for the Tam16 lead molecule was of -51.43 kcal/mol. When comparing this result with the ΔGbind values for the remaining analogs, the drug Tam16 was found to be the highest ranked: this result is in agreement with the experimental results obtained by Aggarwal and collaborators, where it was verified that the IC50 for Tam16 is the smallest necessary to inhibit the Pks13 (IC50 = 0.19 µM). The energy decomposition analysis suggested that the residues which most interact with inhibitors are: Ser1636, Tyr1637, Asn1640, Ala1667, Phe1670, and Tyr1674, from which the greatest energy contribution to Phe1670 was particularly notable. For the lead molecule Tam16, a hydrogen bond with the hydroxyl of the phenol not observed in the other analogs induced a more stable molecular structure. Aggarwal and colleagues reported this hydrogen bonding as being responsible for the stability of the molecule, optimizing its physic-chemical, toxicological, and pharmacokinetic properties.

Angelica Stem: A Potential Low-Cost Source of Bioactive Phthalides and Phytosterols.

Chinese Angelica is a significant medical plant due to the various therapeutic constituents in its root; whereas the aerial part is considered worthless and often discarded as agricultural waste. In this work, phytochemicals from the stem were first systematically analyzed by means of GC⁻MS after derivatization and HPLC⁻MS/MS in multiple reaction monitoring (MRM) mode. Phthalides, ferulic acid, and coniferyl ferulate were detected in the stem; although their content is relatively low in comparison with the root. Some specific compounds, such as p-hydroxybenzoic acid, vanillic acid, protocatechuic acid, caffeic acid, 4-hydroxyphenyl-1, 2-ethanediol, thymol-ß-d-glucopyranoside, etc. and a significant amount of phytosterols (1.36 mg/g stem, mainly ß-sitosterol) were detected in the stem. The extracted oil from the stem contained a considerable amount of phthalides (48.5 mg/g), ß-sitosterol (56.21 mg/g), and stigmasterol (14.03 mg/g); no other bioactive compounds were found that could be potentially used as pharmaceuticals or additives to healthcare food.

Minor compounds of the high purity salvianolic acid B freeze-dried powder from Salvia miltiorrhiza and antibacterial activity assessment.

The study explored the isolation and characterisation of three compounds of high purity salvianolic acid B freeze-dried powder extracted from Salvia miltiorrhiza Bunge. A new salvianolic acid, salvianolic acid V (2) together with two known compounds (3-4) was identified. The antibacterial activity tests showed that compound 2 combined with clinical antibiotics such as Levofloxacin or Colistin sulphate together exhibited potent effects against MRSA or Acinetobacter baumanii. This report has considerably extended our knowledge about the diversity and bioactivity of caffeic acid derivatives from S. miltiorrhiza.

Purity, adulteration and price of drugs bought on-line versus off-line in the Netherlands.

BACKGROUND AND AIMS: On-line drug markets flourish and consumers have high expectations of on-line quality and drug value. The aim of this study was to (i) describe on-line drug purchases and (ii) compare on-line with off-line purchased drugs regarding purity, adulteration and price. DESIGN: Comparison of laboratory analyses of 32 663 drug consumer samples (stimulants and hallucinogens) purchased between January 2013 and January 2016, 928 of which were bought on-line. SETTING: The Netherlands. MEASUREMENTS: Primary outcome measures were (i) the percentage of samples purchased on-line and (ii) the chemical purity of powders (or dosage per tablet); adulteration; and the price per gram, blotter or tablet of drugs bought on-line compared with drugs bought off-line. FINDINGS: The proportion of drug samples purchased on-line increased from 1.4% in 2013 to 4.1% in 2015. The frequency varied widely, from a maximum of 6% for controlled, traditional substances [ecstasy tablets, 3,4-methylenedioxy-methamphetamine (MDMA) powder, amphetamine powder, cocaine powder, 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and lysergic acid diethylamide (LSD)] to more than a third for new psychoactive substances (NPS) [4-fluoroamphetamine (4-FA), 5/6-(2-aminopropyl)benzofuran (5/6-APB) and methoxetamine (MXE)]. There were no large differences in drug purity, yet small but statistically significant differences were found for 4-FA (on-line 59% versus off-line 52% purity for 4-FA on average, P = 0.001), MDMA powders (45 versus 61% purity for MDMA, P = 0.02), 2C-B tablets (21 versus 10 mg 2C-B/tablet dosage, P = 0.49) and ecstasy tablets (131 versus 121 mg MDMA/tablet dosage, P = 0.05). The proportion of adulterated samples purchased on-line and off-line did not differ, except for 4-FA powder, being less adulterated on-line (χ2  = 8.3; P < 0.02). Drug prices were mainly higher on-line, ranging for various drugs from 10 to 23% higher than that of drugs purchased off-line (six of 10 substances: P < 0.05). CONCLUSIONS: Dutch drug users increasingly purchase drugs on-line: new psychoactive substances in particular. Purity and adulteration do not vary considerably between drugs purchased on-line and off-line for most substances, while on-line prices are mostly higher than off-line prices.

Assessment of the Blood-Brain Barrier Permeability of Potential Neuroprotective Aurones in Parallel Artificial Membrane Permeability Assay and Porcine Brain Endothelial Cell Models.

Previously, several aurone derivatives were identified with promising neuroprotective activities. In developing these compounds to target the central nervous system (CNS), an assessment of their blood-brain barrier (BBB) permeability was performed using in vitro BBB models: parallel artificial membrane permeability assay-BBB which measures passive permeability and primary porcine brain endothelial cell model which enables determination of the involvement of active transport mechanism. Parallel artificial membrane permeability assay-BBB identified most compounds with high passive permeability, with 3 aurones having exceptional Pe values highlighting the importance of basic amine moieties and optimal lipophilicity for good passive permeability. Bidirectional permeability assays with porcine brain endothelial cell showed a significant net influx permeation of the aurones indicating a facilitated uptake mechanism in contrast to donepezil, a CNS drug included in the evaluation which only displayed passive permeation. From pH-dependent permeability assay coupled with data analysis using pCEL-X software, intrinsic transcellular permeability (Po) of a representative aurone 4-3 was determined, considering factors such as the aqueous boundary layer that may hinder accurate in vitro to in vivo correlation. The Po value determined supported the in vivo feasibility of the aurone as a CNS-active compound.

Assessment of Angelica sinensis (Oliv.) Diels as a repellent for personal protection against mosquitoes under laboratory and field conditions in northern Thailand.

BACKGROUND: Angelica sinensis (Oliv.) hexane extract (AHE) has been reported as a proven and impressive repellent against laboratory-reared female Aedes aegypti mosquitoes. With the aim of promoting products of plant origin as a viable alternative to conventional synthetic substances, this study was designed to transform AHE-based repellents for exploitable commercial production by enhancing their efficacy and assessing their physical and biological stability as well as repellency against mosquitoes under laboratory and field conditions. METHODS: The chemical profile of AHE was analyzed by qualitative gas chromatography-mass spectrometry (GC-MS) technique. AHE was supplemented with vanillin, as a fixative, and then investigated for repellency and comparison to the standard synthetic repellent, DEET, under both laboratory and field conditions. Determination of physical and biological stability as a repellent was carried out after keeping AHE samples under varying temperatures and for different storage times. RESULTS: GC-MS analysis revealed that AHE contained at least 21 phytochemical compounds, constituting 95.74 % of the total content, with the major constituent of 3-N-butylphthalide (66.67 %). Ethanolic formulations of AHE and DEET showed improvement of repellency in a dose-dependent manner when vanillin was added in laboratory assessment. While 5-25 % AHE alone provided median complete-protection times of 2.0-6.5 h against Ae. aegypti, these times were increased to 4.0-8.5 h with a combination of AHE and 5 % vanillin (AHEv). Protection times against Ae. aegypti were extended from 2.25 to 7.25 h to 4.25-8.25 h when 5-25 % DEET was combined with 5 % vanillin (DEETv). In determining stability, all stored AHE samples exhibited similar characteristics such as liquid phases with aromatic odor comparable to those of fresh preparations. Furthermore, repellent activity of stored AHE samples lasted for at least six months, with varied efficacy (4.5-10.0 h) against Ae. aegypti. Field trials revealed strong repellency from both 25 % AHEv and 25 % DEETv, with complete protection (100 %) against a wide range of local mosquito populations. A total of 5,718 adult female mosquitoes, with the most predominant being Culex quinquefasciatus (41.47 %), Armigeres subalbatus (41.13 %), and Culex vishnui (10.53 %), was collected during field applications. No local skin reaction or other allergic responses was observed during both laboratory and field study periods. CONCLUSIONS: Angelica sinensis proved to have not only impressive repellency against both laboratory Ae. aegypti and a wide range of natural mosquito populations, but also relative stability in physical and biological performance.

[Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans in airborne fine particulate matter and inhalation risk assessment for local residents of Shenzhen].

OBJECTIVE: To explore the levels and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in airborne fine particulate matter (PM25) in Shenzhen and roughly discuss its correlations between PM25 concentration and meteorological factors. METHODS: The high volume air samplers were used to collect the samples in six sampling sites in respective winter and spring phase and summer and autumn phase. Referring to the US EPA TO-9A for dioxins detection methods, the concentrations of the 17 polychlorinated dibenzo-p-dioxins and dibenzofurans in airborne fine particulate matter were determined by HRGC/HRMS. RESULTS: The total concentrations of PCDD/Fs ranged from 0.32 to 9.35 pg/m3, with average of 2.45 pg/ m3. The TEQ concentrations ranged from 0.006 to 0.388 pg I-TEQ/m3, with average of 0.095 pg I-TEQ/m3. The four abundant congeners were found to be OCDD (36.49%), 1, 2, 3, 4, 6, 7, 8-HpCDF (14.89%), OCDF (13.34%) and 1, 2, 3, 4, 6, 7, 8-HpCDD (10.92%). 2, 3, 4, 7, 8-PeCDF was the dominant contributor to toxicity equivalent (TEQ), accounting for 34.65%. Positive relationship was found between the levels of fine particle-bound PCDD/Fs and PM2.5 concentration (r(s) = 0.794, P = 0.006), whereas no correlation was observed for temperature, humidity and atmospheric pressure. Inhalation exposure to PCDD/Fs were 0. 023 pg I-TEQ/(kg · d) for adult and 0.035 pg I-TEQ/(kg · d) for children during winter and spring and relatively higher than those during summer and autumn (0.014 pg I-TEQ/(kg · d). for adult and 0.021 pg I-TEQ/(kg · d) for children respectively). CONCLUSION: The levels of PCDD/Fs in airborne fine particle-bound samples collected in Shenzhen were lower than those in Hangzhou and Beijing.

Assessment of PCDD/Fs formation in the Fenton oxidation of 2-chlorophenol: Influence of the iron dose applied.

Toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may be formed during remediation of chlorinated phenols via Fenton oxidation. To highlight the need for monitoring the production of toxic byproducts in these reactions, this work assessed the influence of iron dose (0.09-0.36 mM) on the Fenton oxidation of 2-chlorophenol (2-CP, 15.56 mM), a potential precursor of PCDD/Fs, by quantifying 2-CP removal and mineralization rates as well as byproducts yields, including PCDD/Fs. Although the increase in the iron dose showed positive contribution to 2-CP oxidation, under the operating conditions of the current study (H2O2 at 20% of the stoichiometric dose and 20 °C), there was no effect on the mineralization rate, and TOC and chlorine balances were far to be closed, depicting the presence of chlorinated organic byproducts in the reaction medium. After 4 h of treatment, the total PCDD/Fs concentrations increased by 14.5-39 times related to the untreated sample when the iron doses tested decreased from 0.36 to 0.09 mM, with preferential formation of PCDFs over PCDDs and dominance of lower chlorinated congeners such as tetra and penta-PCDD/Fs. The treatment with the highest iron dose (0.36 mM) exhibited the lowest PCDD/Fs yields and was thus most successful at mitigating toxic byproducts of the Fenton oxidation, leading to lower sample toxic equivalence (TEQ) value.

In vitro and in vivo assessment of the effect of antiprotozoal compounds isolated from Psoralea corylifolia against Ichthyophthirius multifiliis in fish.

Ichthyophthirius multifiliis, an external fish parasite, often causes significant economic damage to the aquaculture industry. Since the use of malachite green was banned, the search of alternative substance to control I. multifiliis infections becomes stringent. In present study, in vitro and in vivo anti-ich efficacies of isopsoralen and psoralidin, two active compounds isolated from methanol extract of Psoralea corylifolia by bioassay-guided fractionation based on the efficacy of anti-ich encysted tomonts, were evaluated. In vitro antiprotozoal efficacy of psoralidin is much better than that of isopsoralen. Psoralidin can kill all theronts at concentrations of 0.8 mg/L or more during 4 h exposure; and terminate reproduction of I. multifiliis post 6 h exposure of protomonts to 0.9 mg/L and encysted tomonts to 1.2 mg/L. In vivo trials showed that 5 h exposure of infected fish to 2.5 mg/L of psoralidin significantly reduced the number of theronts released from tomonts. Furthermore, we observed that a part of protomonts, collected from infected fish post treatment, presented characteristic morphological changes of apoptosis after staining with Annexin V-EGFP/propidium iodide, indicating the possible mechanism of psoralidin against I. multifiliis trophont in situ. On the basis of these results, psoralidin can be used as a potential lead compound for the development of commercial drug against I. multifiliis.

Clinical assessment of drug-drug interactions of tasimelteon, a novel dual melatonin receptor agonist.

Tasimelteon ([1R-trans]-N-[(2-[2,3-dihydro-4-benzofuranyl] cyclopropyl) methyl] propanamide), a novel dual melatonin receptor agonist that demonstrates specificity and high affinity for melatonin receptor types 1 and 2 (MT1 and MT2 receptors), is the first treatment approved by the US Food and Drug Administration for Non-24-Hour Sleep-Wake Disorder. Tasimelteon is rapidly absorbed, with a mean absolute bioavailability of approximately 38%, and is extensively metabolized primarily by oxidation at multiple sites, mainly by cytochrome P450 (CYP) 1A2 and CYP3A4/5, as initially demonstrated by in vitro studies and confirmed by the results of clinical drug-drug interactions presented here. The effects of strong inhibitors and moderate or strong inducers of CYP1A2 and CYP3A4/5 on the pharmacokinetics of tasimelteon were evaluated in humans. Coadministration with fluvoxamine resulted in an approximately 6.5-fold increase in tasimelteon's area under the curve (AUC), whereas cigarette smoking decreased tasimelteon's exposure by approximately 40%. Coadministration with ketoconazole resulted in an approximately 54% increase in tasimelteon's AUC, whereas rifampin pretreatment resulted in a decrease in tasimelteon's exposure of approximately 89%.

Experimental benznidazole treatment of Trypanosoma cruzi II strains isolated from children of the Jequitinhonha Valley, Minas Gerais, Brazil, with Chagas disease

Trypanosoma cruzi strains from distinct geographic areas show differences in drug resistance and association between parasites genetic and treatment response has been observed. Considering that benznidazole (BZ) can reduce the parasite burden and tissues damage, even in not cured animals and individuals, the goal is to assess the drug response to BZ of T. cruzi II strains isolated from children of the Jequitinhonha Valley, state of Minas Gerais, Brazil, before treatment. Mice infected and treated with BZ in both phases of infection were compared with the untreated and evaluated by fresh blood examination, haemoculture, polymerase chain reaction, conventional (ELISA) and non-conventional (FC-ALTA) serologies. In mice treated in the acute phase, a significant decrease in parasitaemia was observed for all strains. Positive parasitological and/or serological tests in animals treated during the acute and chronic (95.1-100%) phases showed that most of the strains were BZ resistant. However, beneficial effect was demonstrated because significant reduction (p < 0.05%) and/or suppression of parasitaemia was observed in mice infected with all strains (acute phase), associated to reduction/elimination of inflammation and fibrosis for two/eight strains. BZ offered some benefit, even in not cured animals, what suggest that BZ use may be recommended at least for recent chronic infection of the studied region.

The critical role of the operating conditions on the Fenton oxidation of 2-chlorophenol: assessment of PCDD/Fs formation.

This work assesses the influence of the operating conditions H2O2 dose (20 or 100% of the stoichiometric amount), temperature (20 or 70°C), and the presence of chloride in the oxidation medium in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during Fenton treatment of aqueous samples of 2-chlorophenol, 2-CP, one of the strongest precursor of PCDD/Fs. After 4h of oxidation in the experiments carried out with 20% H2O2 chlorinated phenoxyphenols and biphenyls, which are intermediates in PCDD/Fs formation, as well as PCDD/Fs were observed, resulting in concentrations 11 times higher than in the untreated sample. Additionally, when NaCl was also present in the reaction medium, PCDD/Fs were formed at higher extent, with a total concentration 74.4 times higher than in the untreated 2-CP solution. Results depicted a preferential formation of PCDFs over PCDDs, with dominance of lower chlorinated PCDD/Fs (tetra and penta-PCDD/Fs). Besides, the formation of the most toxic PCDD/Fs congeners (2,3,7,8-PCDD/Fs) was not favored under the operating conditions used in this work.

Bioactive stilbenes from Vitis vinifera grapevine shoots extracts.

BACKGROUND: Viticultural residues from commercial viticultural activities represent a potentially important source of bioactive stilbenes such as resveratrol. The main aim of the present study was therefore to isolate, identify and perform biological assays against amyloid-ß peptide aggregation of original stilbenes from Vitis vinifera shoots. RESULTS: A new resveratrol oligomer, (Z)-cis-miyabenol C (3), was isolated from Vitis vinifera grapevine shoots together with two newly reported oligostilbenes from Vitis vinifera shoots, vitisinol C (1) and (E)-cis-miyabenol C (2), and six known compounds: piceatannol, resveratrol, (E)-ε-viniferin (trans-ε-viniferin), ω-viniferin, vitisinol C and (E)-miyabenol C. The structures of these resveratrol derivatives were established on the basis of detailed spectroscopic analysis including nuclear magnetic resonance experiments. All the newly reported compounds were tested for their anti-aggregative activity against amyloid-ß fibril formation. Vitisinol C was found to exert a significant activity against amyloid-ß aggregation. CONCLUSION: Vitis vinifera grapevine shoots are potentially interesting as a source of new bioactive stilbenes, such as vitisinol C.

Quantitative assessment of the formation of polychlorinated derivatives, PCDD/Fs, in the electrochemical oxidation of 2-chlorophenol as function of the electrolyte type.

The electrochemical degradation of 2-chlorophenol (2-CP) on boron-doped diamond (BDD) anodes was carried out using two electrolytes, NaCl and Na2SO4. Both electrolytes supported complete mineralization of 2-CP, but faster rates of degradation were observed in NaCl. After 4 h of oxidation, the total organic carbon (TOC) balance neared 100% with Na2SO4 for identifiable compounds, whereas 4 mM of TOC remained unidentified with NaCl. Since chlorophenols are known to be precursors of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), a rigorous assessment of intermediate products was carried out. When near complete mineralization was achieved, the use of NaCl resulted in the concentration of total PCDD/Fs increasing 2.68 × 10(4) times compared to the untreated sample, and to toxicity values several times higher than the maximum level established by U.S. Environmental Protection Agency for water ingestion. When Na2SO4 was used, the increase in total PCDD/Fs concentration was 134 times lower than with NaCl and there was no significant 2,3,7,8-PCDD/Fs formation. Thus, we emphasize the importance of electrolyte selection in electro-oxidation processes, especially when PCDD/Fs precursors are initially present or may be formed in the treated water samples.

Removal of PCDD/Fs from contaminated sediment and released effluent gas by charcoal in a proposed cost-effective thermal treatment process.

A novel cost-effective thermal treatment technology has been proposed for the removal of PCDD/Fs from contaminated sediment and released effluent gas using charcoal as both an adsorbent and a thermal source. When a reactor was used for thermal treatment, the PCDD/Fs removal efficiency exceeded 98% from the sediment at the three different air superficial velocities employed in this study. The total PCDD/F international toxic equivalent (I-TEQ) contents, both in the treated sediments and effluent gas, were below the Japanese emission standard limit. Analysis of the PCDD/F contents in different fractions showed that large quantities of PCDDs but not PCDFs were evaporated from the sediment and adsorbed in the moist sediment column. This difference was attributed to the formation of PCDDs from pentachlorophenol (PCP) during the cooling process following the thermal treatment process in the reactor. This proposed thermal process provides a promising alternative to the conventional methods.

Assessment of emissions and removal of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) at start-up periods in a hazardous waste incinerator.

UNLABELLED: A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter. IMPLICATIONS: This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.