Source Control Research Articles

The microbial etiology and resistance patterns of cosmetic tourism-related infections in Ireland.

Cosmetic tourism is an increasingly common phenomenon, both in Ireland and internationally. Complications associated with procedures performed abroad may manifest after the patient has traveled back to their home country with patients often presenting to local health services. Such complications can be infectious in nature requiring either antimicrobial therapy and/or source control in the form of wound debridement or radiologically guided interventional procedures. Patients who had presented to a regional plastic surgery unit between September 2021 and December 2022 with complications related to aesthetic procedures performed outside Ireland were identified in this retrospective-prospective design. Medical records were reviewed to ascertain what procedures were performed, where the procedure had taken place, the nature of complications, and microbial culture and sensitivity results. Thirty patients were identified during the study timeframe, predominantly female (n = 28) with a mean age of 40.27years (SD 10.6). Abdominoplasty was the most common procedure (n = 17), and Turkey was the most frequently cited destination (70%). Wound dehiscence accounted for the majority of complications (n = 18). Wound cultures were obtained in 80% (n = 24) of patients and a causative organism was isolated in 85% (n = 34) of cultures. Eighteen species of bacteria were identified and antimicrobial sensitivities were obtained for 16 of these. Antimicrobial resistance to commonly prescribed empiric antibiotics was noted in several isolates. Post-operative infections related to cosmetic tourism are a growing concern in plastic surgery. The bacterial etiology is varied, and antimicrobial resistance poses significant challenges, highlighting the need for early intervention and wound cultures to guide effective management.

Transport and Accumulation of Microplastics from Biosolids to Australian Agricultural Soils: Detection of Microplastics Down to 1 μm.

The shift toward sustainable agriculture involves replacing inorganic fertilizers with organic alternatives like biosolids. However, concerns arise over emerging contaminants, such as microplastics (MPs), which remain largely unregulated. Despite their common use in Australia, the transfer of MPs from biosolids to agricultural soils remains largely unknown. Herein, we have investigated the abundance, characteristics, and transport of MPs resulting from biosolids application in two Queensland agricultural sites. MP concentrations were significantly higher in biosolid-amended soils (average of 1137 MPs/kg) than in reference sites (average of 36 MPs/kg), correlating with the volume, time since application, and frequency of biosolids application. MPs > 25 μm were predominantly polyethylene, polypropylene, and poly(methyl methacrylate) fragments (up to 85%). Fibers constitute only 15-30% of MPs and mainly in larger sizes (average 1011 μm), whereas fragments (average 188 μm) and beads (average 72 μm) had smaller size ranges. Despite analytical challenges using Raman spectroscopy, detected smaller MPs (1-25 μm) were fragments composed of polyethylene, polypropylene, and poly(vinyl alcohol). This study provides the first report of MPs down to 1 μm in Australian agricultural soils. Our findings suggest a need to assess the long-term impact of MPs in biosolids on soil health and food safety. We call on policymakers to consider the implementation of effective MP source control strategies and the development of guidelines for acceptable biosolids application rates.

EP376 - Portal Pyaemia and Fungal Septicaemia Associated with Mesenteric Venous Pneumatosis - Improving Patient Outcomes

Abstract An 82 year old female presented to A&E with a 1 week history of lower abdominal pain, fever, and nausea. She had a known history of sigmoid diverticulosis, however had not had any previous abdominal surgery, and had no other past medical history of note. At presentation she was in septic shock, requiring vasopressor support to maintain her blood pressure. Her abdominal examination revealed left iliac fossa tenderness, however no features of peritonism. Initial investigations revealed a White Cell Count (WCC) 49.3x10^9/L, a C-Reactive Protein (CRP) 191mg/L, and an ALP of 434IU/L. A CT scan of the abdomen and pelvis confirmed acute sigmoid diverticulitis, with radiological features suggesting gas tracking along the inferior mesenteric vein (IMV). An emergency Hartmann’s procedure was performed, and intra-operatively pus was evidence draining directly from the IMV. Pre-operative blood cultures and intra-operative tissue cultures grew Escherichia coli, for which the patient was treated with intravenous meropenem post-operatively. She was transferred to Intensive Care Unit and stepped down to the ward on post-operative day 5. Within the first 48 hours post-operative, the WCC had risen to 64x10^9/L, however within 72 hours of commencing anti-fungals, this dramatically decreased to 16x10^9/L. After this, her recovery was swift, and was discharged shortly after. In the context of acute diverticulitis, any radiological evidence of gas within the portal venous system is likely secondary to portal pyaemia. Urgent operative intervention for source control remains the mainstay of management, with consideration of anti-fungals imperative.

Study on Non-Point Source Pollution Prevention and Control System in Nansi Lake Basin Based on System Dynamics Approach

Agriculture, as an important activity on which human beings depend for their livelihood, brings serious environmental problems while meeting the needs of human survival, among which agricultural non-point source (NPS) pollution is one of the most urgent environmental problems. This study quantitatively assessed the loading characteristics spatial and temporal evolution patterns of two agricultural NPS pollutants, chemical oxygen demand (COD) and ammonia nitrogen (NH3-N), from 2010 to 2020 in the Nansi Lake Basin as an example, and constructed a system dynamics (SD) simulation model to simulate and analyze agricultural NPS pollution under different development and treatment scenarios, based on an investigation of the regional prevention and control strategy of agricultural NPS pollution and the technological system. The results show that the current status of agricultural NPS pollution load in the Nansi Lake Basin is poor, and the level of pollution load is high, showing obvious geographical differences. In terms of temporal changes, the pollution loads of the two pollutants showed a decreasing trend from 2010 to 2020, among which the pollution load of NH3-N showed the largest change. Spatially, the spatial distribution of each type of pollutant has some similarities, with smaller pollution loads in Jining and Zaozhuang and relatively larger pollution loads in Heze and Ningyang. The main source of COD pollution in the Nansi Lake Basin is rural life, with an emission proportion of 52.85%, and the main sources of NH3-N pollution from agricultural NPS pollution in the area are rural life and livestock and poultry farming, with emission proportions of 47.55% and 35.36%, respectively. Under the status quo continuum scenario, the pollution load values for COD are consistently higher than those for NH3-N, so the relative impact of COD is greater. In this study, the principles and methods of SD in system science are adopted to deal with the agricultural NPS pollution of Nansi Lake Basin, and the evolution of its behavioral characteristics are simulated, forecasted, and predicted, and policy experiments are conducted, with a view to providing references for the prevention and control of agricultural NPS pollution in Nansi Lake Basin and further research.

Elizabethkingia bloodstream infections in severely immunocompromised patients: persistent, relapsing and associated with high mortality.

Elizabethkingia species are uncommon causes of bloodstream infections, representing a true opportunistic and multi-drug-resistant pathogen to immunocompromised or vulnerable hosts. Despite this, data are lacking regarding optimal management strategy for infections with this organism, which is associated with significant mortality and morbidity. We describe patient characteristics, management and outcomes in this case series. All inpatients at the Royal Brisbane and Women's Hospital with a positive blood culture for Elizabethkingia spp. were identified by database query. Clinical information including medical history, source of infection, attempts at source control and outcome were collected. Laboratory data including duration of bacteraemia and antimicrobial susceptibility testing were also collected. All patients had severe defects of innate and adaptive immunity. Targeted therapy was started promptly and efforts at source identification and control were appropriately pursued. Despite this, outcomes were generally poor. A previously unrecognized presentation of relapsing infection was described in one case, requiring long-term suppressive antimicrobials to control. One case died as a result of infection and one case was cured, but died soon after due to complications of immunosuppression. Treatment of these organisms is challenging due to limited effective therapy, development of on treatment resistance and profound host immunocompromise. Up-front use of multiple, optimally dosed antimicrobials, attempting source control and attempting to restore host immune function all appear to be key to achieving good outcomes.

Risk factors for positive follow-up blood cultures in critically ill adults with Gram-negative bacteraemia.

To evaluate the utility of follow-up blood cultures (FUBCs) for Gram-negative bloodstream infection (BSI) in ICU patients and identify risk factors for repeat positive cultures. This was a single-centre, retrospective cohort study of critically ill adults with Gram-negative BSI between 1 January 2015 and 1 January 2020. Critically ill patients with one or more blood cultures positive for a Gram-negative organism were included. Descriptive and inferential statistics were performed with an alpha of 0.05. A total of 148 critically ill patients with Gram-negative BSI were included, with 42 patients (28.4%) having one or more positive FUBCs. The majority (66.2%) were admitted to a medical ICU. The most common organisms isolated were Escherichia coli (n = 56, 37.8%) and Klebsiella pneumoniae (n = 26, 17.6%). Significant patient risk factors associated with a positive FUBC on univariate regression included: MDR organisms, immunocompromised status, fever, vasopressor use at time of FUBC, lack of source control attainment, and higher quick Pitt bacteraemia score. Multivariable penalized logistic regression indicated that lack of source control containment and less time from index to FUBC remained significantly associated with repeat positive FUBC. This is the first study to investigate the use of FUBC for Gram-negative BSI in exclusively ICU patients. Risk factors for repeat positive FUBC in this population include lack of source control and less time between index and FUBC. Prospective studies are needed to fully elucidate the role of FUBCs in critically ill patients with Gram-negative BSI.

The response of daytime nitrate formation to source emissions reduction based on chemical kinetic and thermodynamic model

Particulate nitrate is an important component of particulate matter and poses a significant threat to the ecosystem and human health. The gas-phase formation pathway of nitrate is extremely important, which mainly comprises the NO2 oxidation process triggered by OH radicals and the nitrate partitioning process. The response of nitrate to source emission reduction during different pollution periods remains unclear. Here, we applied the chemical kinetic and thermodynamics model to explore the importance oxidation process and partitioning process during different pollution periods based on high-time resolution observation data. The result indicated that with the aggravation of pollution, the partitioning process gradually ceases to be a limiting step in the formation of nitrates. The results of the influencing factor analysis indicate that NO2 concentration and aerosol pH values play a more significant role in the formation of nitrates. Specifically, during the clean period, nitrate formation is sensitive to both NO2 concentration and pH values, but during the pollution period, it becomes sensitive only to NO2 concentration. By combining source apportionment, we explored the response of nitrate formation to source emission reduction, and the results showed that the control of vehicle exhaust emissions and coal combustion sources is more effective in mitigating nitrate pollution. Additionally, this study also emphasized the importance of early prevention and control of pollution sources. This research provides scientific evidence for the precise management and control of nitrates.

Effectiveness of short treatment duration for carbapenemase-producing Enterobacterales in bloodstream-infections: A retrospective cohort study

ObjectiveWe analyse the effectiveness of short courses of adequate treatment in patients with episodes of carbapenemase-producing Enterobacterales bloodstream-infections (CPE-BSI). MethodsPatients with first monomicrobial CPE-BSI episodes who received ≥72 h of appropriate treatment from 2014–2022 were selected. Detection of CPE was established on the basis of phenotypic antibiogram and confirmation by PCR and/or immunochromatographic methods. Patients were classified in short treatment group (STG) those who received 3–10 days of appropriate treatment, and long treatment (LTG) those receiving >10 days. Unfavourable outcome consisted in a composite of global 30-day mortality and/or persistent bacteremia and/or recurrent bacteremia. Inverse probability of treatment weighting (IPTW) analysis was performed to compare the outcome between the two study groups. ResultsWe included 105 CPE-BSI episodes: 99 were caused by OXA-48-like, 4 VIM and 2 KPC carbapenemases. Thirty-nine patients (37.1%) were included in the STG and 66 (62.9%) in LTG. The STG group presented frequent treatment with ceftazidime-avibactam (43.6% vs. 24.2%, P = 0.03) and lower in-hospital stay (21 days vs. 32 days, P = 0.02). Overall, 28 patients (26.7%) presented unfavourable outcome: IPTW analysis showed no differences in the outcome between STG to LTG groups (24.2% vs. 30.8%, weighted-risk difference 6.6%, P = 0.44). Patients with unfavourable outcome presented more frequently source other than urinary-biliary (46.4% vs. 23.4%, P = 0.02), received less frequently ceftazidime-avibactam (14.3% vs. 37.7%, P = 0.02) and presented frequently with absence of source control when indicated (28.6% vs. 13.0%, P = 0.06). ConclusionsShort treatment durations for CPE-BSI episodes may be effective, as long as they are appropriate and source control is performed.

Flexible and Ecological Cotton-Based Dosimeter for 2D UV Surface Dose Distribution Measurements.

This work presents a 2D radiochromic dosimeter for ultraviolet (UV) radiation measurements, based on cotton fabric volume-modified with nitroblue tetrazolium chloride (NBT) as a radiation-sensitive compound. The developed dosimeter is flexible, which allows it to adapt to various shapes and show a color change from yellowish to purple-brown during irradiation. The intensity of the color change depends on the type of UV radiation and is the highest for UVC (253.7 nm). It has been shown that the developed dosimeters (i) can be used for UVC radiation dose measurements in the range of up to 10 J/cm2; (ii) can be measured in 2D using a flatbed scanner; and (iii) can have the obtained images after scanning be filtered with a medium filter to improve their quality by reducing noise from the fabric structure. The developed cotton-NBT dosimeters can measure UVC-absorbed radiation doses on objects of various shapes, and when combined with a dedicated computer software package and a data processing method, they form a comprehensive system for measuring dose distributions for objects with complex shapes. The developed system can also serve as a comprehensive method for assessing the quality and control of UV radiation sources used in various industrial processes.

306. TREATMENT OF ANASTOMOTIC LEAKS AFTER ESOPHAGECTOMY AND GASTRECTOMY FOR CANCER BY MEANS OF ENDOSCOPIC VACUUM THERAPY

Abstract Background Esophagectomy and gastrectomy are the cornerstones of the curative treatment of oesophageal and gastric cancer. In both techniques the risk of anastomotic leak (AL) is high, with rates of up to 21% after esophagectomy and up to 12% after gastrectomy. Mortality and morbidity are high after an AL occurs. Several treatment strategies have been developed for treatment of AL, including surgery, endoscopic stent and endoscopic vacuum therapy (EVT). The aim of this study is to analyse the treatment patterns of the patients with AL treated with EVT. Methods All patients diagnosed of gastric or oesophageal cancer with AL from January 2021 to January 2024 were included in a retrospective study. Baseline data, localization of the tumour, type of resection, type of anastomosis, total time with EVT, number of EVTs used per patient, hospital stay, Clavien-Dindo score and CCI were recorded. A descriptive analysis of the data is performed. Results All 18 patients with AL during the study period were treated with EVT. The tumour was located on the distal third of the oesophagus in 7 patients (38.9%), and stomach (27.8%). The median duration from surgery to the identification of AL was 5 days (IQR 4 – 9). The median duration of the EVT treatment was 18 days (IQR 13 – 23) with a median EVT replacement of 5.5 (IQR 4 – 7). 8 patients (44.4%) did not require ICU stay. Median time to resumption of oral intake was 34 days (IQR 26 –54). Success rate of the EVT therapy was 88.9%. Conclusions EVT is a useful tool for the treatment of AL in esophagogastric surgery. Even though the treatment may be long, it’s success rate in this series is 88.9% and it may avoid ICU stay in some cases. A close monitoring of this patients and the prompt use of additional techniques to assure source control is mandatory.

Maternal sepsis: Clinical pearls for diagnosis and management

Sepsis is a leading cause of maternal morbidity and mortality worldwide. Early recognition and treatment improve outcomes. Multiple sepsis diagnostic screening tools are available and may be used in clinical practice; however, early thorough bedside evaluation of the patient is fundamental. Obstetricians should be able to recognize sepsis and promptly initiate potentially life-saving treatments, such as fluid resuscitation, vasopressors, broad-spectrum antibiotics, and early source control. It is recommended that obstetrical care, including delivery timing, not be altered solely due to the diagnosis of sepsis.

Total outward leakage of face-worn products used by the general public for source control

During Coronavirus disease 2019 pandemic, the general public used any face-worn products they could get to overcome the shortage of N95 respirators and surgical masks. These products, often not meeting any standards, raised concerns about their effectiveness in reducing the spread of respiratory viruses. This study quantified total outward leakage (TOL) of units from 9 face-worn product categories used by members of the general public. A benchtop system was devised to test 2 units from each category on 2 different-sized headforms with silicone elastomer skin. Each unit was donned 5 times per headform. Both face-worn product category and headform size significantly affected TOL (Pvalue < .05). The TOL of tested face-worn products varied from 10% to 58% depending on both model and headform size. Face-worn products donned on the medium headform had a higher mean TOL compared to those donned on the larger headform. Overall, single-layer cloth masks are the least effective measure for source control due to their highest TOL among the tested face-worn products. Three-layer disposable face masks may be a favorable option for source control among the public. A standard should be developed for face-worn product design and manufacturing to accommodate different facial sizes.

Clinical outcomes of lung transplant recipients with pre-transplant Mycobacterium avium complex infection.

Lung transplant recipients (LTRs) are at risk for Mycobacterium avium complex (MAC) infections, in part due to the presence of structural lung disease pre-transplant and relatively higher levels of immunosuppression post-transplant. There is a lack of data regarding outcomes of LTR with MAC infections pre-transplant. This is a single-center retrospective analysis of patients who received lung transplants (LTs) from 2013 to 2020 with 1) evidence of MAC on culture or polymerase chain reaction before or at the time of transplant or 2) granulomas on explant pathology and positive acid-fast bacillus stains with no other mycobacteria identified. Patients were deemed to have MAC pulmonary disease (MAC-PD) if they met the American Thoracic Society/Infectious Disease Society of America criteria. Fourteen patients (14/882, 2%) met inclusion criteria. Seven patients (7/14, 50%) had pre-transplant MAC-PD, four of whom had cavitary disease. None of the 14 patients had smear-positive cultures at the time of transplant. Two patients in our cohort received treatment for MAC before transplant. Thirteen patients were bilateral LTR (13/14, 93%). One single LTR was the sole patient to receive MAC treatment post-transplant. No patients developed MAC-PD after transplant. The bilateral LTR in our cohort did not develop MAC-PD despite not receiving MAC treatment post-transplant. It is possible source control was achieved with native lung explantation. Our observations suggest patients may not uniformly require pre- or post-transplant MAC treatment if they are smear-negative and undergo bilateral LT.

Groundwater quality in high-sulfur coal mining region of India: Spatial distribution, source control, and health risk assessment

The groundwater quality in the vicinity of the Makum coalfield, renowned for its high-sulfur coal deposits, was investigated. The oxidation of sulfur in the coal generates acid mine drainage (AMD), a global environmental challenge that contaminates natural resources. The region's high sulfur coal content intensifies AMD formation, necessitating a comprehensive assessment of its impact on human health and the environment. This study analyzes the water quality parameters such as pH, EC, TDS, Na+, Ca+2, Mg+2, K+, HCO3‐, SO4−2, F−, Cl -, and NO3− in groundwater, findings concerning low pH levels (5.8) and fluoride concentration (0.15 mg/L) compared to standards. Groundwater chemistry was analyzed to identify the sources controlling water composition through Gibbs diagrams, Piper diagrams, and saturation indices. The Gibbs diagram shows that rock weathering is the crucial factor controlling groundwater chemistry, while the Piper diagram indicates Ca-Cl as the Principal water type. Additionally, an in-depth analysis of groundwater chemistry reveals that carbonate dissolution primarily occurs due to minerals like calcite, dolomite, and gypsum, findings supported by saturation indices. The present study yielded an average water quality index of 40.19, indicating excellent to good water quality in 51 out of 52 samples analyzed. The average hazard index values for adults and children were 0.60 and 0.58, respectively, indicating that 49 of 52 samples pose negative non-carcinogenic risks associated with nitrate and fluoride contamination. The irrigation indices, graphical representations such as the Wilcox and Doneen classification, and the USSL diagram elucidate the suitability for irrigation purposes. Moreover, the Principal Component Analysis identified the sources of ions as originating from geogenic processes and mining activities. The study stresses environmental assessments, health risk management, and sustainable practices for groundwater in high-sulfur coal mining areas.

Characterisation of Aqueous Ultra-high Homeopathic Potencies: Nanoparticle Tracking Analysis.

Over the past decade, research using various methods has claimed the material nature, including nanoparticles (NPs), of high homeopathic potencies. The current study aims to verify these findings using NP tracking analysis (NTA). Six independent serial dilutions of commonly used homeopathic medicines-either soluble (Gelsemium, Pyrogenium, Kalium mur) or insoluble (Cuprum, Argentum, Silicea)-were prepared according to European Pharmacopoeia standards. We compared the homeopathic dynamisations (DYNs) in pure water with their potentised controls and with simple dilutions (DIL) up to 30cH/10-60. We also tested the influence of the container (glass or PET) on the solvent controls. We observed the presence of particles from 20 to 300-400 nm in all DYNs, DILs and controls, except in pure unstirred water. The sizes and size distributions of NPs in high homeopathic potencies were smaller than those in controls for soluble sources and larger for insoluble sources, even above 11cH. The opposite behaviour was observed in the number of NPs. When comparing DYN and DIL, the number, size, presence of aggregates or chains and brightness of NPs increased with DYNs, which was also observed above 11cH. Many NPs scattered light of low intensity, indicating the presence of material particles. The container had a significant effect on the number and size of NPs, indicating the involvement of the atmosphere and leaching processes. Homeopathic medicines contain NPs with specific properties, even when diluted beyond Avogadro's number. Homeopathic potentisation is not a simple dilution. The starting material, the solvent used, the type of container and the manufacturing method influence the characteristics of these NPs. The nature of these NPs is not known, but most likely they are a mixture of nanobubbles and elements from the atmosphere and container, including insoluble ones.

Continuous Decline in Direct Incomes for Farmers Threatens the Sustainability of the Grain for Green Project

Understanding the impacts of ecological projects on household livelihoods is important in ensuring their sustainability. However, existing studies typically cover only a limited, discrete temporal point. Insufficient study duration makes it difficult to determine the full impact and dynamics of a project, affecting the veracity of the results. Representing one of the world’s largest investments in an ecosystem service programs, the Grain for Green Project (GGP) has an objective of increasing household incomes. Using data from 7112 questionnaires collected through 12 consecutive years (2007–2018) of field survey monitoring, this study examined the long-term impacts of the GGP on household livelihoods in the Beijing–Tianjin Sandstorm Source Control Project area through comparisons between participant households (PHs) and non-participant households (NPHs). The results show that GGP subsidies significantly increased household incomes only during the period 2007–2015, and their share of total household income decreased from 9.21% in 2007 to 1.62% in 2018. Subsidies for GGP cannot compensate farmers for losses due to the reduction in farmland. The above findings suggest that the effect of subsidies diminishes over time. Increased investment in jobs and skills training is needed to consolidate the GGP results. This provides new perspectives and empirical support for the study of international ecological compensation policies and sustainable development.

Source Control and Antibiotics in Intra-Abdominal Infections.

Intra-abdominal infections (IAIs) account for a major cause of morbidity and mortality, representing the second most common sepsis-related death with a hospital mortality of 23-38%. Prompt identification of sepsis source, appropriate resuscitation, and early treatment with the shortest delay possible are the cornerstones of management of IAIs and are associated with a more favorable clinical outcome. The aim of source control is to reduce microbial load by removing the infection source and it is achievable by using a wide range of procedures, such as definitive surgical removal of anatomic infectious foci, percutaneous drainage and toilette of infected collections, decompression, and debridement of infected and necrotic tissue or device removal, providing for the restoration of anatomy and function. Damage control surgery may be an option in selected septic patients. Intra-abdominal infections can be classified as uncomplicated or complicated causing localized or diffuse peritonitis. Early clinical evaluation is mandatory in order to optimize diagnostic testing and establish a therapeutic plan. Prognostic scores could serve as helpful tools in medical settings for evaluating both the seriousness and future outlook of a condition. The patient's conditions and the potential progression of the disease determine when to initiate source control. Patients can be classified into three groups based on disease severity, the origin of infection, and the patient's overall physical health, as well as any existing comorbidities. In recent decades, antibiotic resistance has become a global health threat caused by inappropriate antibiotic regimens, inadequate control measures, and infection prevention. The sepsis prevention and infection control protocols combined with optimizing antibiotic administration are crucial to improve outcome and should be encouraged in surgical departments. Antibiotic and antifungal regimens in patients with IAIs should be based on the resistance epidemiology, clinical conditions, and risk for multidrug resistance (MDR) and Candida spp. infections. Several challenges still exist regarding the effectiveness, timing, and patient stratification, as well as the procedures for source control. Antibiotic choice, optimal dosing, and duration of therapy are essential to achieve the best treatment. Promoting standard of care in the management of IAIs improves clinical outcomes worldwide. Further trials and stronger evidence are required to achieve optimal management with the least morbidity in the clinical care of critically ill patients with intra-abdominal sepsis.

A time-domain study on the effects of noise source incidence on plenum window with active noise control

Active noise control (ANC) applied to the built environment on windows presents itself as a potential solution to reduce noise exposure for residents living near major noise sources since windows are typically the primary path for noise intrusion on a building's facade. The plenum window design seeks to address the dual dichotomy of ventilation and acoustic dilemma that plagues hot-humid and highly noise-polluted cities. In the present study, a time-domain approach is developed to investigate the effect of varying impinging angles of noise sources on the acoustic performance of a plenum window which can represent different storeys of the receiving end of noise exposure. Furthermore, the ANC performance of a control system affected by the varying noise sources is explored in this study. While most ANC studies have limited their scope of study to frequency domain investigations, the present study takes a time-domain approach to account for the causality of the ANC system concerning the primary noise source and secondary control source, which is thus more accurate to the behaviour of a real-time ANC controller. A total of 121 simulation studies were performed, and the findings show that the plenum window's PNC (passive noise control) is affected by the incident angle of a noise source based on its tonal frequency, which is pronounced near the aperture's cut-off frequency, faperture. However, the ANC performance due to varying incident angles of primary noise remains unaffected even at high frequencies with a standard deviation, σANC < 1 dB except for the 630 Hz tonal frequency, which coincides with faperture.

Insight into the inhibition mechanisms of Ca-, N-, S-containing compounds on persistent organic pollutant formation from the thermal reaction of anthracene on copper chloride

Four inhibitors (CaO, CaS, CH4N2S, and (NH4)2SO4) were employed to inhibit the formation of multiple unintentional persistent organic pollutants (POPs) and environmentally persistent free radicals (EPFRs) using anthracene as a precursor, with CuCl2 serving as both a transition metal catalyst and chlorine source. The inhibition mechanisms were elucidated in terms of chlorine immobilization, catalyst deactivation, and free radical regulation. The inhibition efficiency of the four inhibitors on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) ranged from 64.7 % to 98.4 %, with the corresponding inhibition rates on toxic equivalency quantity ranging from 86.3 % to 99.7 %. The distribution of homologs shifted towards less chlorinated species, indicating effective suppression of chlorination. Calcium- and nitrogen-containing compounds consumed chlorine sources by forming CaCl2, CaClOH, and NH4Cl, while sulfur-containing compounds deactivated catalysts by forming CuSO4. EPFRs derived from anthracene were identified as carbon-centered anthracene-type and anthraquinone-type radicals. Positive correlations were observed between POPs and EPFRs concentrations, suggesting the pivotal role of organic free radicals as intermediates in POPs formation. Anthraquinones derived from anthracene underwent decomposition, recombination and chlorination, leading to the formation of PCDD/Fs and PCBs. The addition of inhibitors reduced EPFRs concentrations by 74.2–95.1 %. Sulfur- and nitrogen-containing inhibitors generated radicals that attacked POPs precursors and intermediates, forming heteroatomic compounds and inhibiting POPs formation. These findings enhanced the understanding of the source control mechanisms of POPs and provided theoretical and technical support for the synergistic inhibition of POPs and EPFRs in industrial thermal processes.

A macro-level life cycle environmental-economic impact and benefit assessment of sponge cities in China

Urban runoff source control facilities (URSCFs) are integral components of Sponge City (SC), playing a pivotal role in providing ecosystem services and managing water quality and quantity. To accurately assess the performance of URSCFs, it is crucial to quantify their environmental and economic impacts. However, previous studies have predominantly focused on location-specific case studies, lacking a macro-level perspective necessary for informing public policy development pertaining to SC initiatives. This study aims to bridge this gap by conducting a macro-level life cycle assessment across China's 16 initial pilot SCs, categorized into three zones based on their annual rainfall volume control rate α (i.e., Zone II (80 % to 85 % for α), Zone III (75 % to 85 % for α), and Zone IV (70 % to 85 % for α)). By simulating five rainfall drainage scenarios, we delve into the environmental benefits of SC construction. The results indicate that Zone III incurs the highest environmental and economic costs during the construction phase, followed by Zones II and IV. In Zone III, bioretention contribute significantly to the environmental impact and economic cost, while constructed wetland and detention cells are the key contributors for Zone II. During the operation phase, Zone III demonstrates the largest environmental and economic benefits, with Zone IV and II trailing behind. The investment payback period for SCs in all zones is less than eight years, with Zone IV recovering costs the fastest (3.9 years) and Zone II the slowest (7.5 years). Facilities like detention cells, green roofs, and permeable pavements tend to have longer payback periods. Based on our findings, we recommend that Zone II exercise caution in constructing detention cells, permeable pavements, and wetlands, while Zone III should carefully consider green roofs and bioretention to optimize SC investments. Due to the fewer URSCFs constructed in Zone IV, it exhibits the lowest environmental impact compared to Zones II and III. Our research provides valuable insights to support policymaking with regards to future SC planning and development.