[Association between weight control and recurrence of atrial fibrillation after catheter ablation in overweight and obese patients].

Objectives: This study explored the relationship between weight control and atrial fibrillation (AF) recurrence after catheter ablation in overweight and obese patients. Methods: We prospectively enrolled consecutive 333 overweight and obese patients aged 28 to 87 years old, who underwent catheter ablation for AF in Beijing Anzhen Hospital between October 2015 and February 2016. Data of patients' characteristics, laboratory examination and treatment were collected at baseline. Each patient was followed up at 3, 6 and 12 months after ablation to collect information on weight, AF recurrence, stroke, major bleeding, hospitalization for cardiovascular reasons and death, etc. Patients were divided into weight controlled group (ΔBMI<-1 kg/m(2)) and weight uncontrolled group (ΔBMI≥-1 kg/m(2)), according to the changes in the most recent exposure BMI before AF recurrence in patients with recurrence or the BMI at 12 months' follow-up in patients without recurrence and the BMI at baseline. Multivariate logistic regression was performed to adjust other known risk factors of AF recurrence and to explore the association between weight control and AF recurrence after catheter ablation. Results: There were 54 patients in weight controlled group and 279 patients in weight uncontrolled group. There were no significant differences in age, gender, education level, left atrial size and history of hypertension between the two groups (all P>0.05). The proportion of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was higher in the weight controlled group (50.0%(27/54) vs. 34.8%(97/279), P=0.034). However, there was no significant difference in the proportion of patients with obesity (33.3% (18/54) vs. 29.7% (83/279)), paroxysmal AF (59.3% (32/54) vs. 56.6% (158/279)) and AF duration less than 5 years (76.9% (40/52) vs. 65.4% (178/272)) between the weight controlled group and the uncontrolled group. During 1-year follow-up after ablation, the recurrence rate of AF was significantly lower in the weight controlled group than that in the weight uncontrolled group (14.8% (8/54) vs. 32.6%(91/279), P=0.009). Multivariable logistic regression analysis shows that weight control is independently associated with a lower postoperative AF recurrence rate (OR=0.40, 95%CI 0.18-0.90, P=0.026). Conclusion: Weight control is strongly associated with a lower AF recurrence rate after catheter ablation in overweight and obese patients.

[Schistosomiasis control in China from 2012 to 2021: progress and challenges].

Schistosomiasis has been endemic in China for more than 2 000 years, which causes huge morbidity, social and economic burdens. Guided by the national specific strategic programs and criteria for schistosomiasis, tremendous achievements have been gained for schistosomiasis elimination in China. This paper reviews the progress of schistosomiasis control and endemic status of schistosomiasis in China during the period from 2012 to 2021, analyzes the challenges to achieve the goal of schistosomiasis elimination in China by 2030, and proposes suggestions for future schistosomiasis control programs.

[Clinical effects of pedicled omental flap transplantation in repairing secondary rejection wounds after brain pacemaker implantation].

Objective: To explore the clinical effects of pedicled omental flap transplantation in repairing secondary rejection wounds after brain pacemaker implantation. Methods: A retrospective observational study was conducted. From January to August 2021, 5 patients with secondary rejection wounds after brain pacemaker implantation who met the inclusion criteria were admitted to the Wound Repair Center of Ruijin Hospital of Shanghai Jiao Tong University School of Medicine, including 3 males and 2 females, aged 56-69 years, with the wound developed at the pulse generator implantation site in the chest in 2 cases, at the connection site of the wire and electrode behind the ear in 2 cases, and at both the chest and the back of the ear in 1 case. All the wounds were repaired by pedicled omental flap transplantation. The wound area after debridement was 2-15 cm2. After operation, the wound healing and related complications (pain, infection, incisional hernia, omental flap necrosis, etc.) were observed. During follow-up, the recurrence of the wound was observed. Results: The wounds of all 5 patients healed within 2 weeks after operation, without related complications. During follow up of 12-18 months, 1 patient got a recurrence of rejection wound behind the left ear 4 months after surgery and eventually had the brain pacemaker removed; the other 4 patients had no recurrence of wounds. Conclusions: Pedicled omental flap transplantation can repair the secondary rejection wounds after brain pacemaker implantation safely and effectively, with few postoperative complications.

[Sharing the WHO guideline on control and elimination of human schistosomiasis to achieve the goal of schistosomiasis elimination in China].

Currently, the national schistosomiasis control program of China is moving from transmission interruption to elimination, and there are multiple challenges during the stage moving towards the progression of schistosomiasis elimination, including a high difficulty in shrinking snail-infested areas, unstable achievements for infectious source control, imperfect surveillance system and a reduction in schistosomiasis control and administration. Based on the core suggestions proposed in the 2022 WHO guideline on control and elimination of human schistosomiasis, recommendations on schistosomiasis surveillance system building, development of novel diagnostics, adjustment of the schistosomiasis control strategy and maintaining and improvements of the schistosomiasis control capability are proposed for the national schistosomiasis control program of China in the new era according to the actual status of schistosomiasis control in China. Formulation of the national schistosomiasis control strategy and goal from One Health perspective, verification of transmission interruption and elimination of schistosomiasis, precision implementation of schistosomiasis control interventions with adaptations to local circumstances, development and application of highly sensitive and specific diagnostics are recommended for elimination of schistosomiasis in China. In addition, the implementation of the 2022 WHO guideline on control and elimination of human schistosomiasis may guide the elimination of schistosomiasis in China.

[Contribution to global implementation of WHO guideline on control and elimination of human schistosomiasis by learning successful experiences from the national schistosomiasis control program in China].

Schistosomiasis is a parasitic disease that seriously hinders socioeconomic developments and threatens public health security. To achieve the global elimination of schistosomiasis as a public health problem by 2030, WHO released the guideline on control and elimination of human schistosomiasis on February, 2022, with aims to provide evidence-based recommendations for schistosomiasis morbidity control, elimination of schistosomiasis as a public health problem, and ultimate interruption of schistosomiasis transmission in disease-endemic countries. Following concerted efforts for decades, great achievements have been obtained for schistosomiasis control in China where the disease was historically highly prevalent, and the country is moving towards schistosomiasis elimination. This article reviews the successful experiences from the national schistosmiasis control program in China, and summarizes their contributions to the formulation and implementation of the WHO guideline on control and elimination of human schistosomiasis. With the progress of the "Belt and Road" initiative, the world is looking forward to more China's solutions on schistosomiasis control.

[Analysis of the new WHO guideline to accelerate the progress towards elimination of schistosomiasis in China].

On February 2022, WHO released the evidence-based guideline on control and elimination of human schistosomiasis, with aims to guide the elimination of schistosomiasis as a public health problem in disease-endemic countries by 2030 and promote the interruption of schistosomiasis transmission across the world. Based on the One Health concept, six evidence-based recommendations were proposed in this guideline. This article aims to analyze the feasibility of key aspects of this guideline in Chinese national schistosomiasis control program and illustrate the significance to guide the future actions for Chinese national schistosomiasis control program. Currently, the One Health concept has been embodied in the Chinese national schistosomiasis control program. Based on this new WHO guideline, the following recommendations are proposed for the national schistosomiasis control program of China: (1) improving the systematic framework building, facilitating the agreement of the cross-sectoral consensus, and building a high-level leadership group; (2) optimizing the current human and livestock treatments in the national schistosomiasis control program of China; (3) developing highly sensitive and specific diagnostics and the framework for verifying elimination of schistosomiasis; (4) accelerating the progress towards elimination of schistosomiasis and other parasitic diseases through integrating the national control programs for other parasitic diseases.

Beneficial response to gabapentin portraying with interval change of brain SPECT imaging in a case with failed back surgery syndrome.

WHAT IS KNOWN AND OBJECTIVE: Failed back surgery syndrome (FBSS) is a well-recognized consequence of surgery of the lumbar spine. Here, we present a case with FBSS associated neuropathic pain. CASE SUMMARY: During hospital stay, the patient was stabilized with gabapentin 200 mg twice a day and this was titrated to a dose of 1200 mg per day over the period of 1 week. The treatment produced a substantial reduction in his episodic pain. We assessed regional cerebral blood flow (rCBF) by using brain single photon emission computed tomography (SPECT) scans, which were performed before and after gabapentin treatment 1 week later. The examination of the first SPECT showed decreased uptake in left fronto-temporal-parietal region. The latter one showed much improvement of the above areas. WHAT IS NEW AND CONCLUSION: The gabapentin has beneficial effect in the FBSS associated neuropathic pain. Besides, this case suggests the association between rCBF and pain associated with FBSS, as well as the association of gabapentin and altered blood flow of brain cortex.

[To master the rules and characteristics of wound repair for wound healing promotion].

Wound repair has its inherent pathophysiological mechanism, presenting a complex network regulation. However, these contents are not detailed exhaustively or systematically in the medical undergraduate education system in China and even the world. Therefore, it is difficult for those clinicians who are not engaged in wound repair related research to fully understand the mechanism of wound repair and its relationship with the clinical process. To provide a reference for clinical work, this article summarizes the sequential, local, time-bounding characteristics of wound healing related to the clinical practice through the understanding of the relevant mechanisms of wound repair.

[Effectiveness and cost analysis of two chemical molluscicides in hilly schistosomiasis-endemic regions].

OBJECTIVE: To investigate the effectiveness and cost of 50% and 80% wettable powder of niclosamide ethanolamine salt (NESWP) and 26% metaldehyde and niclosamide suspension concentrate (MNSC) in hilly schistosomiasis-endemic regions, so as to provide insights into the selection of chemical molluscicides in hilly regions. METHODS: In September 2020, a wasteland in Guanshanqiao Village, Yanrui Township, Yushan County of Jiangxi Province was selected as the experimental region, which was sectioned into five blocks and defined as four experimental groups (A1, A2, B, C) and a blank control group (D). 80% NESWP were given at doses of 1 g/m2 and 1.5 g/m2 in groups A1 and A2 using the spraying method, 50% NESWP was given at a dose of 2 g/m2 in Group B using the spraying method, and 26% MNSC was at a dose of 4 g/m2 in Group C using the spraying method, while no chemical treatment was given in Group D. Snail survey was performed using a systematic sampling method before chemical treatment and 1, 3, 7 d and 15 d post-treatment to examine the molluscicidal effect, and all molluscicidal costs were estimated to calculate the cost of chemical treatment per 1 m2 and the cost of the reduction in the mean density of living snails per 1%. RESULTS: The highest mortality of snails was 78.95% and the lowest density of living snails was 0.2388 snails/0.1 m2 in the experimental groups within 7 d of chemical treatment, and the highest mortality of snails was 94.74% and the lowest density of living snails was 0.058 0 snails/0.1 m2 7 d post-treatment. There were no significant differences in the snail mortality among the A1, A2, B and C groups 1 (χ2 = 2.250, P > 0.05), 3 (χ2 = 1.779, P > 0.05) or 15 d post-treatment (χ2 = 2.286, P > 0.05), while a significant difference was detected in the snail mortality among the four groups 7 d post-treatment (χ2 = 7.990, P = 0.046). In addition, there were no significant differences in the snail mortality between A1 and A2 groups 1 (χ2 = 0.724, P > 0.05), 3 (χ2 = 0.584, P > 0.05), 7 (χ2 = 0.400, P > 0.05) or 15 d post-treatment (χ2 = 0.251, P > 0.05). The costs of chemical treatment per 1 m2 were 0.58, 0.60, 0.64 Yuan and 0.73 Yuan in groups A1, A2, B and C, and the costs of the mean density of living snail per 1% reduction were 19.29, 20.44, 21.68 Yuan and 23.53 Yuan in groups A1, A2, B and C, respectively. CONCLUSIONS: 80% NESWP shows a high molluscicidal efficacy and low cost in hilly schistosomiasis-endemic regions.

[Key points and research priorities of schistosomiasis control in China during the 14th Five-Year Plan Period].

Schistosomiasis was once endemic in 12 provinces (municipalities, autonomous regions) along and south of the Yangtze River basin, which seriously damages human health and hinders socioeconomic developments in China. Following the concerted efforts for 70 years, remarkable achievements have been gained in the national schistosomiasis control program of China. However, there are still multiple challenges for elimination of schistosomiasis in the country. This paper describes the current status of schistosomiasis and the challenges during the progress towards the elimination of schistosomiasis, and proposes the goals, key points and research priorities of schistosomiasis control in China during the 14th Five-Year Plan Period.

[Endemic status of schistosomiasis in People's Republic of China in 2020].

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2020, and analyzed the data collected from the national schistosomiasis prevention and control system and national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, Shanghai Municipality, Zhejiang Province, Fujian Province, Guangdong Province and Guangxi Zhuang Autonomous Region continued to consolidate the achievements of schistosomiasis elimination, and Sichuan and Jiangsu provinces maintained the criteria of transmission interruption, while Yunnan, Hubei, Anhui, Jiangxi and Hunan provinces maintained the criteria of transmission control by the end of 2020. A total of 450 counties (cites, districts) were found to be endemic for schistosomiasis in China, with 28 376 endemic villages covering 71 370 400 people at risk of infections. Among the 450 endemic counties (cities, districts), 74.89% (337/450), 21.87% (98/450) and 3.33% (15/450) achieved the criteria of elimination, transmission interruption and transmission control of schistosomiasis, respectively. By the end of 2020, 29 517 cases with advanced schistosomiasis were documented in China. In 2020, 11 117 655 individuals received inquiry examinations and 1 798 580 were positive; 5 263 082 individuals received serological tests and 83 179 were sero-positive. A total of 273 712 individuals received stool examinations and 3 were positive, including one case of acute schistosomiasis. In 2020, snail survey was performed in 19 733 endemic villages in China and Oncomelania snails were found in 7 309 villages, accounting for 37.04% of all surveyed villages, with 15 villages identified with emerging snail habitats. Snail survey covered an area of 736 984.13 hm2 and 206 125.22 hm2 snail habitats were found, including 1 174.67 hm2 emerging snail habitats and 1.96 hm2 habitats with infected snails. In 2020, 544 424 bovines were raised in the schistosomiasis-endemic areas of China, and 147 887 received serological examinations, with 326 positives detected, while 130 673 bovines received stool examinations, with no positives identified. In 2020, there were 19 214 patients with schistosomiasis receiving praziquantel chemotherapy, and 964 103 person-time individuals and 266 280 herd-time bovines were given expanded chemotherapy. In 2020, molluscicide treatment was performed in 136 141.92 hm2 snail habitats, and the actual area of chemical treatment was 71 980.22 hm2, while environmental improvements were performed in snail habitats covering an area of 1 464.03 hm2. Data from the national schistosomiasis surveillance sites of China showed that the mean prevalence of Schistosoma japonicum infections were both zero in humans and bovines in 2020, and no S. japonicum infection was detected in snails. The results demonstrate that the overall endemic status of schistosomiasis remains at a low level in China and the goal of the National Thirteenth Five-Year Plan for Schistosomiasis Control was achieved as scheduled; however, the endemic situation of schistosomiasis rebounded in local areas. Precision schistosomiasis control and intensified monitoring of the endemic situation and transmission risk of schistosomiasis are required to be performed to facilitate the progress towards elimination of schistosomiasis steadily.

[Pay attention to the exposure risk of patients with chronic wounds on the way to hospital during coronavirus disease 2019 epidemic prevention and control].

Statistics show that 76.74% (4 688) of 6 109 patients with chronic wounds are over 50 years of age; the proportion of patients with underlying diseases in all age groups above 50 years ranges from 78.25% to 100.00%. Among the underlying diseases of chronic wound patients, the top four diseases are diabetes mellitus, cardiovascular and cerebrovascular diseases, hypertension, and respiratory diseases. The above underlying diseases and ages of patients are the susceptibility factors of coronavirus disease 2019 released by National Health Commission of China. It is an unavoidable fact that the patients with chronic wounds have to go to the hospital for treatment prescribed by the physician. At the same time, we found that quite a few patients preferred going far afield in choosing hospital for treatment due to various reasons. During the prevention and control of coronavirus epidemic, this " go far afield" style of seeking medical treatment may increase the exposure risk during travelling. Accordingly, we convened 36 wound care clinics in different regions in Shanghai to implement the " Five Measures" encouraging the patients with chronic wounds to seek medical treatment nearby. The principle of this operation is that when seeking medical treatment, patients with chronic wounds should try their best to reduce the travel distance as much as possible to minimize the exposure risk during the epidemic period, which will in turn support the campaign of epidemic prevention and control.

[Implications, spiritual characteristics and practical significance of Chinese schistosomiasis control culture].

The culture of schistosomiasis control is specific in the history of Chinese culture. Broadly speaking, the culture of schistosomiasis control is a summary of specific social mood, social consciousness and material culture created by Chinese populations during the progress of schistosomiasis control since the founding of the People's Republic of China. Narrowly speaking, the culture of schistosomiasis control is the spiritual culture that is jointly created and nurtured by schistosomiasis control workers since the founding of the People's Republic of China. The spiritual features of Chinese schistosomiasis control culture are characterized by the patriotism and care about the people, the matter-to-fact attitude, the pioneering and enterprising spirit, and the spirit of sacrifice and dedication. The ultimate goal of the research on the culture of schistosomiasis control is to facilitate the achievement of the strategic goal of Healthy China 2030 as scheduled, accelerate the progress towards elimination of schistosomiasis, and to promote the sustainable development of schistosomiasis control in China.

[Challenges and countermeasures of schistosomiasis control in Hunan Province in the new era].

This paper describes the current epidemic characteristics and endemic status of schistosomiasis, analyzes the main challenges of schistosomiasis control and proposes the emphasis and interventions for future schistosomiasis control activities in Hunan Province, so as to provide insights into the elimination of schistosomiasis in Hunan Province.

[Thinking on schistosomiasis control under the strategy of China's Yangtze River Economic Belt].

The construction of Yangtze River Economic Belt has been included in the national strategy of China, aiming to improve the economic level of the whole population, and to build a green ecological corridor with the joint development of economy, balance, ecology and equity. Yangtze River Economic Belt is the main area where schistosomiasis is endemic. During the economic construction, the prevention and control of schistosomiasis should be strictly carried out to facilitate the progress towards schistosomiasis elimination in China. In this paper, the endemic situation of schistosomiasis in Yangtze River Economic Belt areas and the possible impact on the schistosomiasis control were analyzed. In addition, a few suggestions were proposed for schistosomiasis control in Yangtze River Economic Belt areas.

[Endemic status of schistosomiasis in People's Republic of China in 2018].

This report presented the endemic status of schistosomiasis in the People's Republic of China at a national level in 2018, and analyzed the data collected from the national schistosomiasis prevention and control system and 453 national schistosomiasis surveillance sites. Among the 12 provinces (municipality and autonomous region) endemic for schistosomiasis in China, 5 provinces (municipality and autonomous region), including Shanghai, Zhejiang, Fujian, Guangdong and Guangxi, continued to consolidate the achievements of schistosomiasis elimination, Sichuan Province achieved transmission interruption and 6 provinces of Yunnan, Jiangsu, Hubei, Anhui, Jiangxi and Hunan achieved transmission control by the end of 2018. There were 450 endemic counties (cities, districts) covering 260 million people, specifically including 28 456 endemic villages covering 70.059 7 million people at risk of infection. Among the 450 endemic counties (cities, districts), 58.44% (263/450), 27.56% (124/450) and 14.00% (63/450) reached the criteria of elimination, transmission interruption and transmission control, respectively. By the end of 2018, a total of 29 214 advanced schistosomiasis cases were documented in China. In 2018, a total of 11.127 6 million individuals received inquiry examinations and 2.062 9 million were positive; 7.191 4 million individuals received serological tests and 138.5 thousand of them were positive, 532.2 thousand individuals received stool examinations and 8 were positive in China. In 2018, snail survey was performed in 19 821 endemic villages and Oncomehania snails were found in 7 321 villages, accounting for 36.94% of all surveyed villages, with 3 newly detected villages with snails in China. Snail survey covered an area of 590 241.01 hm2 and 168 319.41 hm2 snail habitats were found, including emerging snail habitats of 61.28 hm2; however, no infected snails were identified. In 2018, a total of 646 823 bovines were raised in the schistosomiasis endemic areas of China, and 225 258 received serological examinations, with 2 638 positives detected, while 164 803 bovines received stool examinations, with 2 positives identified. In 2018, there were 90 388 patients with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 1 490 594 person-times; there were two bovines with schistosomiasis receiving praziquantel chemotherapy, and expanded chemotherapy was given to 352 577 bovine-times; chemical treatment was conducted in an area of 141 660.87 hm2, including an actual mollusciciding area of 75 308.26 hm2, and environmental improvements were performed in an area of 4 738.37 hm2 in China. Data from the 453 national schistosomiasis surveillance sites of China showed that the mean Schistosoma japonicum infection rates were 0.001 5% and zero in humans and bovines in 2018, respectively, and no infected snails were found. The results demonstrate that the endemic situation of schistosomiasis appears a tendency towards a continuous decline in China; however, there is still a risk of schistosomiasis transmission, and challenges remain in achieving the target set in the Thirteenth Five-Year National Plan for Schistosomiasis Control in 2020 in some regions.

[Progress of research on influencing factors of condom use among female sex workers].

Heterosexual transmission has become the main route of HIV transmission in China. As the main body of commercial heterosexual transmission, female sex workers (FSW) have a high-risk behavior of inconsistent condom use that increase the risk of HIV infection and spread. This review summarizes associated factors of condom use among FSW such as demographic characteristics, condom negotiation, sexual partner type, sexual intercourse, violence and HIV testing, which can provide reference for the future prevention and research among the FSWs.

Sustained virological response to interferon reduces cirrhosis in chronic hepatitis C: a 1,386-patient study from Taiwan.

BACKGROUND: The long-term benefits of interferon-based therapy on preventing cirrhosis at non-cirrhotic stage in chronic hepatitis C patients are not fully clarified. AIM: To evaluate the effectiveness of interferon-based therapy regarding to cirrhosis prevention in non-cirrhotic chronic hepatitis C patients. METHODS: A total of 1386 biopsy-proven, non-cirrhotic chronic hepatitis C patients (892 received interferon-based therapy and 494 untreated) were enrolled. RESULTS: Fifty-six untreated and 51 treated (24 sustained virologic responders and 27 non-responders) patients developed cirrhosis during a mean follow-up period of 5.0 (1-16) and 5.1 (1-15.3) years, respectively. The annual incidences of cirrhosis in untreated and treated groups were 2.26 and 1.11% (non-responders: 1.99%, sustained responders: 0.74%), respectively. The 15-year cumulative incidence of cirrhosis was significantly lower in treated (9.9%) than untreated patients (39.8%, P = 0.0008, log-rank test). The 14.5-year cumulative incidence of cirrhosis was significantly lower in sustained responders (4.8%) compared with non-responders (21.6%, P = 0.0007) and untreated patients (36.6%, P < 0.0001). The difference was not significant between non-responders and untreated controls. Cox proportional hazards regression showed sustained virologic responders and younger age were independent negative factors for cirrhosis development. CONCLUSION: A sustained virologic response secondary to IFN-based therapy could reduce cirrhosis development in chronic hepatitis C patients.

Effects of calcium-based sorbents on PCDD/F formation from pentachlorophenol combustion process.

Calcium-based sorbents are widely employed to reduce the acidic gases emission from combustion processes, and also have effects on trace organic pollutants formation and emission. Batch experiments were conducted to investigate the effects of calcium-based sorbents on pentachlorophenol (PCP) forming PCDDs/Fs during high temperature combustion processes. The results indicated that highly chlorinated PCDD/F homologues were the predominant dioxin products from PCP thermo decomposition, and only minor increasing of PCDDs happened when Ca/Cl ratio was lower than 1, while a major jump occurred when Ca/Cl ratio increased from 1 to 2. The CaO addition clearly promoted the production of all chlorinated dibenzo-p-dioxins homologue and 4-7DFs homologue. Comparison of total PCDD/F emission and its I-TEQ for three different calcium-based sorbents addition (CaO, CaCO3, basic fly ash) indicated that CaO and fly ash containing CaO had almost the same promotion effects on PCDDs/Fs originated from PCP, while CaCO3 inhibit PCDD/F formation greatly with inhibition efficiency up to 70%. Such effects may be partly proved by the observed clearly different micro-surface structures of their reaction residues. The mechanism of CaO on condensation and dechlorination reactions for PCP forming PCDDs and acid-base interaction were proposed to speculate the promotion effects of CaO, and the reaction precedence was used to speculate the inhibition effects of CaCO3 on PCDDs/Fs originated from PCP. The results of the present paper might be useful for the industrial application of calcium-based sorbents to control PCDD/F emission.