Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

The Changes in Broad-spectrum Antimicrobial Consumption during the COVID-19 Pandemic in a Japanese Acute Tertiary-care Hospital: An Interrupted Time-series Analysis

Objective The novel coronavirus disease 2019 (COVID-19) pandemic has spread worldwide, and hospitals in Japan have been forced to respond to the situation. This study evaluated the broad-spectrum antimicrobial use before and during the COVID-19 pandemic in an acute tertiary-care hospital. Methods This single-center, retrospective study was conducted between January 2019 and June 2021. Patients We reviewed patients treated with three broad-spectrum antipseudomonal agents: carbapenems, tazobactam/piperacillin, and cefepime. Monthly aggregated hospital antimicrobial consumption was measured as days of therapy (DOTs) per 1,000 patient-days, and the monthly incidences of Clostridioides difficile infection (CDI), multidrug-resistant Pseudomonas aeruginosa (MRPA), and carbapenemase-producing Enterobacteriaceae (CPE) were recorded. Results The median monthly carbapenem-DOTs during the pre-pandemic and pandemic era were 8.4 and 8.2 per 1,000 patient-days, respectively. A time-series analysis showed non-significant changes in the level between periods (coefficients: 2.08; 95% confidence interval [CI]: -2.9 to 7.0; p=0.44). No change in the trend of monthly carbapenem-DOTs was observed after intervention. No post-intervention changes in the incidence of MRPA or CPE were observed; however, the trend in the incidence of CDI per 1,000 patient-days significantly differed between the two periods (coefficient: -0.04; 95% CI: -0.07, 0.00; p=0.01), and a downward trend was observed in the monthly CDI incidence during the COVID-19 period. Conclusion The consumption of broad intravenous antimicrobial agents has not changed significantly during the pandemic. We need to maintain the quality of medical care, including antimicrobial stewardship, even in specialized resource-limited facilities during a pandemic.

Challenges to Accurate Estimation of Methane Emission from Septic Tanks with Long Emptying Intervals

Septic tanks in low- and middle-income countries are often not emptied for a long time, potentially resulting in poor pollutant removal efficiency and increased greenhouse gas emissions, including methane (CH4). We examined the impact of long emptying intervals (4.0-23 years) on the biochemical oxygen demand (BOD) removal efficiency of 15 blackwater septic tanks and the CH4 emission rates of 23 blackwater septic tanks in Hanoi. The average BOD removal efficiency was 37% (-2-65%), and the average CH4 emission rate was 10.9 (2.2-26.8) g/(cap·d). The emptying intervals were strongly negatively correlated with BOD removal efficiency (R = -0.676, p = 0.006) and positively correlated with CH4 emission rates (R = 0.614, p = 0.001). CH4 emission rates were positively correlated with sludge depth (R = 0.596, p = 0.002), but against expectation, negatively correlated with BOD removal efficiency (R = -0.219, p = 0.451). These results suggest that shortening the emptying interval improves the BOD removal efficiency and reduces the CH4 emission rate. Moreover, the CH4 emission estimation of the Intergovernmental Panel on Climate Change, which is a positive conversion of BOD removal, might be inaccurate for septic tanks with long emptying intervals. Our findings suggest that emptying intervals, sludge depth, and per-capita emission factors reflecting long emptying intervals are potential parameters for accurately estimating CH4 emissions from septic tanks.

A two-color dual-comb system for time-resolved measurements of ultrafast magnetization dynamics using triggerless asynchronous optical sampling

We report on an Er-doped fiber (EDF)-laser-based dual-comb system that allows us to perform triggerless asynchronous optical sampling pump-probe measurements of ultrafast demagnetization and spin precession in magnetic materials. Because the oscillation frequencies of the two frequency-comb light sources are highly stabilized, the pulse-to-pulse timing jitter is sufficiently suppressed, and data accumulation without any trigger signals is possible. To effectively induce spin precession in ferromagnetic thin films, the spectral bandwidth of the output of one of the EDF frequency comb sources is broadened by a highly nonlinear fiber and then amplified at a wavelength of about 1030 nm by a Yb-doped fiber amplifier. The output of the other frequency comb source is converted to about 775 nm by second harmonic generation. We used this system to observe ultrafast demagnetization and spin precession dynamics on the picosecond and nanosecond time scales in a permalloy thin film. This time-domain spectroscopy system is promising for the rapid characterization of spin-wave generation and propagation dynamics in magnetic materials.

A simplified material flow analysis employing local expert judgment and its impact on uncertainty

Material flow analysis (MFA) is an effective tool for waste management, but low- and middle-income countries lack essential data for MFA. This study proposed a simplified MFA (sMFA) utilizing local expert judgment (LEJ) and examining the impact of simplification on its uncertainty. A stochastic sMFA model was developed for nitrogen and phosphorus in urban Mandalay, Myanmar. This model was compared with the intensive MFA (iMFA) model employing intensive surveys for primary data collection. For the total loadings to the environment, the medians of the sMFA were higher by 3% and 11%, respectively, for nitrogen and phosphorus than those of the iMFA. The widths of the 80% confidence intervals of these loadings in the sMFA, normalized by those in the iMFA, were - 0.05 and - 0.11, respectively. The three largest flows to the environment were the same for the two models: on-site sanitation effluent/leakage, greywater, and industrial wastewater. Large median gaps between the models were observed for industrial wastewater, fecal sludge, and human excreta, associated with informal waste management, whereby LEJ did not work well. Overall, the sMFA demonstrated a good estimation of nitrogen and phosphorus flows with limited increase of uncertainty, still requiring focused attention on informal waste streams.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10163-023-01660-5.

Repetitive administration of cultured human CD34+ cells improve adenine-induced kidney injury in mice

BACKGROUND

There is no established treatment to impede the progression or restore kidney function in human chronic kidney disease (CKD).

AIM

To examine the efficacy of cultured human CD34+ cells with enhanced proliferating potential in kidney injury in mice.

METHODS

Human umbilical cord blood (UCB)-derived CD34+ cells were incubated for one week in vasculogenic conditioning medium. Vasculogenic culture significantly increased the number of CD34+ cells and their ability to form endothelial progenitor cell colony-forming units. Adenine-induced tubulointerstitial injury of the kidney was induced in immunodeficient non-obese diabetic/severe combined immunodeficiency mice, and cultured human UCB-CD34+ cells were administered at a dose of 1 × 10⁶/mouse on days 7, 14, and 21 after the start of adenine diet.

RESULTS

Repetitive administration of cultured UCB-CD34+ cells significantly improved the time-course of kidney dysfunction in the cell therapy group compared with that in the control group. Both interstitial fibrosis and tubular damage were significantly reduced in the cell therapy group compared with those in the control group (P < 0.01). Microvasculature integrity was significantly preserved (P < 0.01) and macrophage infiltration into kidney tissue was dramatically decreased in the cell therapy group compared with those in the control group (P < 0.001).

CONCLUSION

Early intervention using human cultured CD34+ cells significantly improved the progression of tubulointerstitial kidney injury. Repetitive administration of cultured human UCB-CD34+ cells significantly improved tubulointerstitial damage in adenine-induced kidney injury in mice via vasculoprotective and anti-inflammatory effects.

Seasonal effects, spatial distribution, and possible sources of microplastics in the Chao Phraya River estuary, Thailand

Microplastics (MPs) in estuaries are sources of plastic debris that enter the marine environment. However, there is limited information on the seasonal effect on the accumulation of MPs in the estuaries of Thailand. The abundance and spatial distribution of MPs in the dry and wet seasons were investigated in the Chao Phraya River estuary, and possible emission sources were traced. Dominant factors affecting the distribution patterns of MPs have also been reported. All collected water samples contained MPs, with a mean abundance of 4.0 ± 2.8 × 10⁵ particles/km² in the wet season and 5.2 ± 3.3 × 10⁵ particles/km² in the dry season. Fragments were mostly observed, with polypropylene and polyethylene being the dominant polymers. The findings also showed that accumulation of MPs was directly influenced by the river discharge rate into the estuary. Further, the spatial distribution of MPs was closely related to seasonal variations in sea surface currents. Microplastic pollution status with seasonal variations and possible emission sources could provide important information to the government and local environmental organizations for MP pollution prevention and future MP studies in estuarine environments.

Discovery of orally bioavailable inhibitors of MALT1 with in vivo activity for psoriasis

We report the design, synthesis, and biological activity of a series of compounds that exhibit potent mucosa-associated lymphoid tissue lymphoma translocation 1 (MALT1) inhibition. Structural transformation of the substructures of a starting compound gave amidomethyl derivatives and sulfonylguanidine derivatives that exhibited potent inhibition of MALT1. Compound 37 had good oral bioavailability and showed anti-psoriatic activity in an imiquimod-induced psoriasis mouse model after oral administration.

The importance of infectious disease specialists consulting on a weekly basis in a Japanese tertiary care hospital: A retrospective observational study

Limited data are available regarding part-time infectious disease consultations (IDCs) and their importance in tertiary care teaching hospitals in Japan. This is a retrospective review of IDCs from June 2016 to March 2021 and describes IDC services provided by part-time infectious disease specialists once a week for 4 hours, and their impact on the quality of medical care, including antimicrobial stewardship. Data, such as the requesting department, requesting reasons, and final diagnoses, were analyzed. In April 2018, part-time infectious disease specialists launched consultation services and attended an antimicrobial stewardship team conference. Meropenem, tazobactam/piperacillin, and cefepime monthly days of therapy (DOT) were calculated to assess the effect of each intervention; a pre-post analysis was conducted using the Kruskal-Wallis test. Additional quality improvement (QI) projects related to infectious diseases were implemented. There were 237 IDCs during the study period. Consultations were mostly requested by the General Internal Medicine, Emergency Medicine, and Cardiology departments. The most common diagnoses were bone/joint, respiratory, and genitourinary infections. Infectious disease services, even on a part-time basis, achieve good outcomes in patient management, antimicrobial stewardship, and QI projects. DOT/1000 patient-days were reduced for meropenem and cefepime, while it increased for tazobactam/piperacillin. The DOT/1000 patient-days for the 3-antipseudomonal agents significantly decreased during this period. After implementing the QI tetanus vaccination project in the Emergency Room, the number of tetanus toxoid vaccinations per month increased.

Rapid and efficient removal of organic matter from sewage sludge for extraction of microplastics

Microplastic pollution is recognized as an emerging global issue; however, no standardized method for the extraction of these pollutants from the environment currently exists and existing methods are ineffective for specific environmental matrices. An appropriate organic matter removal method is essential for the extraction of microplastics from organic-rich sludge to minimize interference during their identification and enhance compatibility of the identification steps. The present study aimed to establish an effective technique for the digestion of organic matter-rich sludge using hydrogen peroxide and Fenton's reagent at varying temperatures, times, and concentrations of an iron catalyst. The organic matter removal efficiency of the five protocols utilized varied from 81.5 % to 87.1 %. Polymers such as polyvinyl chloride (PVC), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and polystyrene (PS) retained most of their physical and chemical properties after the treatments, with minor changes in the surface area, weight, and FTIR spectra properties. Polyethylene terephthalate (PET), PET fiber, polyamide (PA) fiber, and polymethyl methacrylate (PMMA) fiber were significantly degraded via treating with H₂O₂ at 50 °C for 24 h. Protocol 4, treating with Fenton's reagent (H₂O₂ (30 %) + (0.05 M) FeSO₄.7H₂O) at 50 °C for 1 h is proposed as a rapid and effective method for the removal of organic matter from sludge. In addition to its rapidity, this method minimally impacts most polymers, and its high organic matter removal efficiency is associated with a significant reduction of suspended solids in sludge. The present study provides a validated approach that facilitates as an effective organic removal step during the extraction of MPs in sludge.

Exposure, risk and predictors of hexabromocyclododecane and Tetrabromobisphenol-A in house dust from urban, rural and E-waste dismantling sites in Thailand

In this study, for the first time, we determined concentrations of hexabromocyclododecane (HBCDD) and tetrabromobisphenol-A (TBBPA) in house dust and estimated human exposure to these substances in houses located in an e-waste dismantling site and in urban and rural residential areas of Thailand. The median HBCDD concentration in urban residential houses (2.10 ng g^-1) was similar to that in houses in an e-waste dismantling site (2.05 ng g^-1, p > 0.05) and slightly higher than that in rural residential houses (1.11 ng g^-1, p > 0.05). In contrast, significantly higher TBBPA concentrations were present in house dust from an e-waste dismantling site (median = 720 ng g^-1; range = 44-2300 ng g^-1) compared to those in urban (68.6 ng g^-1; 3.5-300 ng g^-1, p < 0.001) and rural residential areas (17 ng g^-1; 2.0-201 ng g^-1, p < 0.001). TBBPA concentrations increased with the increasing presence of electronic devices and a decreasing distance to the e-waste dismantling site. These results suggest that e-waste dismantling activities may contribute to TBBPA contamination of house dust. The median estimated daily intake (EDI) of HBCDD and TBBPA through dust ingestion for toddlers exceeded that for children and adults. However, EDI values for HBCDD and TBBPA from all age groups were below the oral reference dose guideline value suggested by the US National Research Council and National Toxicology Program (NTP).

Assessment of microplastic contamination in the urban lower Chao Phraya River of Bangkok city, Thailand

Rivers are one of the major pathways for the transportation of microplastics (MPs) from land-based sources to the ocean. However, there are only a few studies on MPs in freshwater environments, particularly in Asian countries. In this study, MP contamination in the Chao Phraya River in selected locations distributed throughout Bangkok, Thailand was investigated. MPs were collected using a Manta net with a mesh size of 335 μm. After digestion and distinction based on density, MPs were observed using a stereomicroscope, and polymer types were identified using Fourier Transform Infrared Spectroscopy. MP concentrations detected in the five sampling locations of the river water from upstream to downstream were 11, 35, 40, 15, and 4 particles/m³, with an average concentration of 21±16 particles/m³. Most MPs were identified as either fragments or sheets/films. Polypropylene was the dominant polymer type. The number of MPs increases as their size decreases. Potential sources of MPs may include the degradation of single-use plastic products, especially containers and plastic packaging. MP concentrations and characteristics varied for different locations, indicating different sources and pathways of MPs in urban contexts. Further investigation on the different pathways of the transportation of MPs to river water from land-based sources is required.

Gli1+-PDL Cells Contribute to Alveolar Bone Homeostasis and Regeneration

The periodontal ligament (PDL) contains mesenchymal stem cells (MSCs) that can differentiate into osteoblasts, cementoblasts, and fibroblasts. Nevertheless, the distribution and characteristics of these cells remain uncertain. Gli1, an essential hedgehog signaling transcription factor, functions in undifferentiated cells during embryogenesis. Therefore, in the present study, the differentiation ability of Gli1⁺ cells was examined using Gli1-CreERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. In 4-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were only slightly detected in the PDL, around endomucin-expressing blood vessels. These cells had proliferated over time, localizing in the PDL as well as on the bone and cementum surfaces at day 28. However, in 8-wk-old iGli1/Tomato mice, Gli1/Tomato⁺ cells were quiescent, as most cells were not immunoreactive for Ki-67. These cells in 8-wk-old mice exhibited high colony-forming unit fibroblast activity and were capable of osteogenic, chondrogenic, and adipogenic differentiation in vitro. In addition, after transplantation of teeth of iGli1/Tomato mice into the hypodermis of wild-type mice, Tomato fluorescence indicating the progeny of Gli1⁺ cells was detected in the osteoblasts and osteocytes of the regenerated bone. These results demonstrate that Gli1⁺ cells in the PDL were MSCs and could contribute to the alveolar bone regeneration.

Staphylococcus pettenkoferi bacteremia in a tertiary care hospital in Japan: Report of three cases

Staphylococcus pettenkoferi is a coagulase-negative staphylococci (CoNS) species first isolated in 2002. Human infections caused by S. pettenkoferi are rare. We herein report three cases of S. pettenkoferi bacteremia in a tertiary care hospital in Japan. Staphylococcus pettenkoferi can be a causative pathogen of catheter related blood stream infection including complicated infection, and unknown source of bacteremia. All of the patients presented with fever and shaking chills, and good clinical outcome. Further research is needed to determine the role of this organism as a pathogen and frequency.

Human source identification by using a human-associated Escherichia coli genetic marker in the Mae Klong River, Thailand

Contamination caused by microbial fecal pollution in water bodies is a serious problem in many countries, especially in low- and middle-income countries. Therefore, fecal source tracking is an important method used to understand the source of fecal contamination and to decrease the hazard of waterborne diseases that occurs in the environment. In this study, a human-associated genetic marker for Escherichia coli (H8) was used to investigate the source of fecal contamination in the Mae Klong River, Thailand. Real-time PCR was performed with this marker for 500 E. coli isolates collected from 10 sampling sites along the river, including MK10 (upstream) to MK1 (downstream). The results showed that the proportions of H8-positive isolates were 46, 14, 10, 18, 14, 38, 12, 26, 32, and 14% at MK10-MK1, respectively. All positive proportions were significantly different between the locations (p < 0.001). The higher occurrence of E. coli with H8 marker detection indicated that domestic wastewater was largely discharged without proper treatment, which is attributable to the high population and the absence of proper sewage treatment in those areas.

Horizontal variation of microplastics with tidal fluctuation in the Chao Phraya River Estuary, Thailand

Microplastic (MP) pollution in estuarine environments is poorly characterized globally, although they are extensive buffer regions between terrestrial, freshwater and seawater environments. This research aims to investigate MP pollution levels and variations of MPs abundance with tidal fluctuation. Fourteen samples were collected from the surface water of the Chao Phraya River Estuary, Thailand using the Manta net at flood and ebb tides. The average abundance of microplastics at flood tide was 5.16 × 10⁵ particles/km² and at ebb tide was 3.11 × 10⁵ particles/km². The abundance of microplastics in the estuary was directly related to the tidal fluctuation, creating an accumulation of microplastics in the study area. Polypropylene, polyethylene, and polystyrene were the most common polymers. The findings provide important information on the pollution status of microplastics in the Chao Phraya River Estuary and the variation of suspended microplastics with tidal fluctuation should be considered in future estuarine microplastic studies.

Seasonal and gender impacts on fecal exposure trends in an urban slum

Seasonal and gender impacts have not been well considered in fecal exposure assessment, especially in low- and middle-income countries. This study examined the seasonal and gender impacts on fecal exposure trends in children through daily living activities in an urban slum in Bangladesh. We determined Escherichia coli concentrations in seven types of environmental samples (n = 232) and the activity data of children via diary recording, questionnaires, and interview surveys. Daily and monthly exposures were stochastically estimated for drinking, eating, pond bathing, well bathing, and hand-to-mouth contact. Of the five pathways, pond bathing and drinking contributed a large part of the daily and monthly exposure. Significant seasonal differences were observed in daily exposures for bathing, which were higher in the rainy season (2.59 × 10² CFU/day for boys and 6.19 × 10^-1 CFU/day for girls) than in the dry season (1.69 × 10²; 4.30 × 10^-2), because of longer pond bathing time and more contaminated bathing water in the rainy season. In contrast, eating had significantly higher exposure in the dry season (3.71 × 10; 3.22 × 10) than the rainy season (1.50 × 10; 1.24 × 10) due to the higher dish contamination. Significantly higher daily exposure was observed in the bathing for boys than girls, as boys spent longer time for bathing at a heavily contaminated pond.

Exfiltration and infiltration effect on sewage flow and quality: a case study of Hue, Vietnam

Sewage generated in Southeast Asia is typically characterized by small per-capita flow and low concentration. This study investigated the impacts of exfiltration (leaking-out) and infiltration (leaking-in) on sewage flow and quality in Hue, Vietnam. Sewage flow and quality were continuously monitored at the sewer outlet of a residential drainage area for 68 and 82 days during dry and rainy seasons, respectively. Infiltration was estimated based on the least sewage flow before morning. Lithium tracer tests were conducted to estimate the exfiltration ratio. The results indicated that sewage of the target sewer was weaker than the typical weak-strength sewage even on no-rain days of the dry season. Monitoring of electrical conductivity indicated that rainfall persistently decreased the sewage concentration for a maximum duration of 228 h. The estimated infiltration accounted for 11% and 62% of the total sewage inflow to the sewer during dry and rainy seasons, respectively. The tracer test indicated that exfiltration ratios during the dry and rainy seasons were 65.6% and 24.0%, respectively. As a result of developing the water balance, only 23% of the water supplied to the area reached the sewer outlet in the dry season, while 123% flowed in the rainy season. These results demonstrate that exfiltration decreased the sewage flow in the dry season, while infiltration significantly increased the sewage flow and decreased the sewage concentration in the rainy season. To the best of our knowledge, this is the first study to quantify the impacts of infiltration and exfiltration on sewage in Southeast Asia.

Greenhouse Gas Emissions from Blackwater Septic Systems

Septic systems are potentially a significant source of greenhouse gases (GHGs). The present study investigated GHGs from the blackwater septic systems that are widely used especially in low- and middle-income countries. Ten blackwater septic tanks in Hanoi, Vietnam, were investigated using the floating chamber method. The average methane and carbon dioxide emission rates measured at the first compartment (65% of total capacity) of the septic tanks were 11.92 and 20.24 g/cap/day, respectively, whereas nitrous oxide emission was negligible. Methane emission rate was significantly correlated with septage oxidation-reduction potential (ORP) (R = -0.67, p = 0.034), chemical oxygen demand mass (R = 0.78, p = 0.007), and biochemical oxygen demand mass (R = 0.78, p = 0.008), whereas it was not significantly correlated with water temperature (R = 0.26, p = 0.47) and dissolved oxygen (R = -0.59, p = 0.075) within the limited range: 30.6-31.7 °C and 0.03-0.34 mg-O₂/L. The methane emission rates from septic tanks accumulating septage for >5 years were significantly higher than those at 0-5 years (p = 0.016). These results suggest that lower ORP and higher biodegradable carbon mass, in association with longer septage storage periods are key conditions for methane emissions. To the best of our knowledge, this is the first study to characterize GHG emissions from septic systems.

Data-independent acquisition with ion mobility mass spectrometry for suspect screening of per- and polyfluoroalkyl substances in environmental water samples

Per- and polyfluoroalkyl substances (PFASs) have environmentally persistent, and the various types of PFASs have been detected in water environments. Many previous studies have performed data-dependent acquisition (DDA) of mass spectra from an environmental sample by high-resolution mass spectrometry to identify PFAS suspects individually. In comparison, the data-independent acquisition (DIA) of comprehensive mass spectra of the sample is a technology which enables to know the occurrences of suspects and non-targets simultaneously. However, it is difficult to associate the fragment ions of targeted precursor ions by retention time only, because of the existence of co-eluting ions derived from environmental samples. Since the separation of ions is not enough with only the conventional DIA method, here, we attempted to support it using ion mobility mass spectrometry (IMS) to distinguish the relevant ions from co-eluting ions by drift time. Firstly, suspect screening of PFASs with eternal database resulted in determining 32-96 PFAS suspects in firefighting foam impacted groundwater samples (n = 8) by suspect screening. Among all the pairs of respective precursor ions and fragment ions of the PFAS suspects, 5%-19% (4-9 PFASs) of them were associated without considering the drift time of IMS, while 37%-49% (15-43 PFASs) of them were associated with considering the drift time. The consideration of the drift time increased the association ratios in all samples. In a sample, most precursor ions could be associated with their fragment ions (41 of 43 PFASs) because at least one probable fragment ion was observed among three of maximum intensity fragment ions. Thus, the method improved the identification by excluding the unrelated co-eluting ions by IMS. Moreover, the method can acquire a certain reliable MS/MS spectra of suspects in environmental samples in one analysis. It is not essential to conduct instrumental analyses again for samples stored for a long time even when the data sets and/or methodologies of data analyses are modified (e.g., the original database, screening list, or statistical filtering/data cleaning approach). It will be particularly useful for studies that must analyze a large number of environmental samples.

Evaluation of a human-associated genetic marker for Escherichia coli (H8) for fecal source tracking in Thailand

High levels of microbial fecal pollution are a major concern in many countries. A human-associated genetic marker for Escherichia coli (H8) has recently been developed for fecal source tracking. The assessment of the H8 marker performance is crucial before it can be applied as a suitable method for fecal source tracking in each country. The performance (specificity and sensitivity) of the H8 marker was evaluated by using non-target host groups (cattle, buffalo, chicken, duck, and pig feces) and target host groups (influent and effluent from a wastewater treatment plant and septages). SYBR based real-time PCR (polymerase chain reaction) was done on 400 E. coli isolates from non-target and target host groups after E. coli isolation. It was found that the specificity from animal feces samples collected in Thailand was 96%. Moreover, influent, effluent, and septage samples showed the values of the sensitivity at 18, 12, and 36%, respectively. All of the non-target host groups were found to be significantly different with positive proportions from the target host group (septage samples) (p ≤ 0.01). Based on the results, this marker is recommended for use as a human-associated E. coli marker for identifying sources of fecal pollution in Thailand.

The impact of an empiric superior vena cava isolation added to pulmonary vein isolation for non-paroxysmal atrial fibrillation associated with left atrial low voltage areas

Introduction

Left atrial low-voltage areas (LVAs) are associated with recurrence after radiofrequency catheter ablation of atrial fibrillation (AF). However, the impact of LVAs on recurrence after an empiric pulmonary vein isolation (PVI) plus superior vena cava isolation (SVCI) strategy for non-Paroxysmal AF (PAF) patients remains unclear.

Purpose

We evaluated the impact of LVAs on the recurrence of atrial tachyarrhythmias (ATs)/AF in patients who underwent an empiric SVCI added to the PVI for non-PAF.

Methods

We enrolled 153 consecutive patients with non-PAF who underwent a PVI alone (PVI group; n=51) or empiric PVI plus SVCI (PVI+SVCI group; n=102). Left atrial voltage maps were constructed during sinus rhythm to identify the LVAs (&lt;0.5 mV). No patients underwent a substrate modification of the LVAs. We divided the patients into two groups based on the LVAs (with or without an LVA &gt;5% of the left atrial surface area) and investigated the ATs/AF free survival rate after the initial and multiple procedures.

Results

LVAs were identified in 65% and 73% of the PVI and PVI + SVCI groups, respectively (P=0.319). In the PVI group, the 18-month ATs/AF-free survival was 61% of the patients without LVAs and 27% of patients with LVAs after the initial session (P=0.018) (Figure 1-A). Seventy-two percent of the patients without LVAs and 46% of those with LVAs were free from ATs/AF after multiple sessions (P=0.083) (Figure 1-B). In the PVI+SVCI group, 50% of the patients with LVAs and 61% of those without LVAs had no recurrence after the initial session (P=0.374) (Figure 2-A). Moreover, there was no significant difference in the 18-month ATs/AF-free survival between the patients with and without LVAs after multiple sessions (73% vs. 79%; P=0.520) (Figure 2-B).

Conclusion

A PVI alone strategy for non-PAF patients with LVAs had limited efficacy for the outcomes, even with multiple procedures. However, an SVCI may have the potential to compensate for an impaired outcome in patients with LVAs.

Funding Acknowledgement

Type of funding source: None

Arterial stiffness could reflect increased cardiac load and reduced pulmonary function in the general population

Background

Pulmonary function is known to decrease with age and reduced pulmonary function has been reported to be associated with all-cause mortality and cardiovascular death. The association between pulmonary impairment and atherosclerosis was reported previously but has not been investigated sufficiently in the general population.

Purpose

We hypothesized that arterial stiffness could reflect increase of cardiac load and reduced pulmonary function. The present study aimed to investigate whether increased cardiac load and reduced pulmonary function could affect arterial stiffness in the general population.

Methods

Subjects undergoing their health check-up were enrolled. Plasma B-type natriuretic peptide (BNP) levels and serum high-sensitivity cardiac troponin I (hs-cTnI) levels were measured to evaluate cardiac load and myocardial damage. Radial augmentation index (rAI) was measured to investigate arterial stiffness using HEM-9000AI device. Subjects with an ST-T segment abnormality on the electrocardiogram, renal insufficiency, cancer, active inflammatory disease, or a history of cardiovascular events and pulmonary disease were excluded. Pulmonary function was assessed using spirometry by calculating forced vital capacity (FVC) as a percentage of predicted value (FVC%-predicted), forced expiratory volume in 1 second (FEV1) as a percentage of predicted value (FEV1%-predicted), and the ratio of FEV1 to FVC (FEV1/FVC).

Results

A total of 1100 subjects aged 57 years were enrolled and their median values of BNP and hs-cTnI were 15.5 and 2.3 pg/ml. The levels of rAI were significantly associated with the levels of BNP after adjustment for possible confounders in multivariate regression analysis, but were not with the levels of hs-TnI. While the parameters of pulmonary function were inversely associated with the levels of rAI and hs-cTnI after adjustment for possible confounders in the multivariate regression analysis, but not with the levels of BNP. The other multivariate regression analyses where BNP, hs-cTnI, parameters of pulmonary function, and the other possible factors were simultaneously included as independent variables revealed that the BNP levels and the FVC%-predicted or FEV1%-predicted, besides age, gender, smoking status, body mass index, blood pressure, heart rate, creatinine, fasting plasma glucose, and triglyceride, were significantly associated with the levels of rAI.

Conclusions

The significant associations of rAI with BNP and pulmonary function were revealed in the general population. These findings support that arterial stiffness could reflect increased cardiac load and reduced pulmonary function, in apparently healthy individuals.

Funding Acknowledgement

Type of funding source: None

A profile analysis with suspect screening of per- and polyfluoroalkyl substances (PFASs) in firefighting foam impacted waters in Okinawa, Japan

Per- and polyfluoroalkyl substances (PFASs) are a group of persistent contaminants detected in firefighting foam impacted waters. Previous studies have performed suspect and non-target screening by high-resolution mass spectrometry (HRMS) to determine the composition of PFAS contamination and to discover unknown PFASs. Here, we performed a profile analysis with suspect screening against two lists in the NORMAN Suspect List Exchange in firefighting foam impacted environmental and drinking water (n = 18) collected in Okinawa, Japan, in April 2019. Samples were analyzed by liquid chromatography (LC) quadrupole time-of-flight (QTOF) MS in electron spray ionization mode. Suspect screening returned 116 candidate PFASs with their molecular weights, functional groups, and perfluoroalkyl chain lengths. Long-chain perfluoroalkyl acids (PFAAs) and some of their precursors were specifically found around the firefighting training area. Short-chain PFAAs were assumed to be formed from precursors by environmental processes. Perfluoroalkyl sulfonamide precursors were found to be transformed to perfluoroalkyl sulfonic acids (PFSAs) in the drinking water treatment process. In contrast, biological activated carbon filtration formed perfluoroalkyl carboxylic acids (PFCAs). The PFAS profile showed that a large number of different substances needs to be considered.

Informal Emptying Business in Mandalay: Its Reasons and Financial Impacts

Globally, 2.8 billion people use on-site sanitation facilities, which need regular emptying of accumulated fecal sludge. Illegal dumping from informal emptying businesses, one of the major challenges in environmental management, is widely observed. Considering Mandalay, Myanmar, this study aimed to determine why informal emptying businesses are selected and estimate the lost revenue for a formal emptying service provider (FP) due to the informal businesses. We interviewed 400 households on their recognition and experiences regarding emptying services and willingness-to-pay for improved service. Revenue loss was estimated by comparing the present and theoretical maximum revenues. Results showed that 91.0% of households recognized FP only. Among 134 emptying-experienced households, 32.8%, 59.7%, and 4.5% chose FP with legal contact, FP with illegal contact, and informal service providers, respectively. The service fees from FP with illegal contact did not become revenue for FP; this was a major informal emptying business in the city. Differently from previous studies, the major illegal dumping was done by FP in this area. A great financial loss was estimated that FP lost 76.5% of the theoretical maximum revenue due to informal business. Logistic regression analysis indicated people's intention to shorten the waiting time through illegal contact, even by paying a higher fee. As emptying services are typically required immediately after fecal sludge is over-accumulated, shorter waiting times and faster contact methods were the reasons why the informal business was selected. Less bureaucratic and more customer friendly system could reduce revenue loss, charge more, and increase profits.

A new method to search for per- and polyfluoroalkyl substances (PFASs) by linking fragmentation flags with their molecular ions by drift time using ion mobility spectrometry

Per- and polyfluoroalkyl substances (PFASs) are a group of anthropogenic organic fluorinated compounds that have been detected widely. To discover unknown PFASs, previous researchers have applied high-resolution mass spectrometer using fragmentation flagging approach with common fragment ion at the same retention time as the flags. However, it was difficult to search for their molecular ion from co-eluting peaks in the full-scan spectrum at a specific retention time. Here, we attempted to utilize drift time acquired by ion mobility spectrometry for making linkages between fragment ions and their molecular ions. For validating the process, standard solution spiked with PFASs were analyzed by liquid chromatography/ion mobility - quadrupole time-of-flight mass spectrometry (LC/IM-QTOF-MS). Fluorinated fragment ions (fragmentation flags) were categorized into three classes: Class 1 (120 types of [C_xF_y]^-), Class 2 (123 types of [C_xF_yO]^-), Class 3 (131 types of [C_xF_yO₃S]^-) and all overlapping fragmentation flags detected at an identical retention time were bundled together as a "flag set". Injecting standard mixed solution of 20 types of PFASs resulted in picking up 20 flag sets by fragmentation flagging. All the fragmentation flags were detected within a designated range of drift time, and their molecular ion was confirmed as a PFAS spiked in the standard solution even when co-eluting compounds were found at almost same retention time. This method was applied to a household fire extinguisher liquid, resulting in finding out nine molecular ions. Therefore, the new linking method achieved rapid searching for the prospective molecular ions using LC/IM-QTOF-MS.

Occurrence and characteristics of microplastics in surface road dust in Kusatsu (Japan), Da Nang (Vietnam), and Kathmandu (Nepal)

Microplastics (MPs, plastics < 5 mm) are a growing concern in ecosystems, being found in the soil and water environment. One of the primary sources of MPs has been suspected to be road dust in urban areas as it can flow into waters with runoff. To understand the occurrence of MPs (100 μm-5 mm) in surface road dust of three cities (Kusatsu, Shiga, Japan; Da Nang, Vietnam; and Kathmandu, Nepal), we collected surface road dust samples. The samples were pretreated (organic matter decomposition and gravity separation), and all MP candidates were individually observed by microscope for color, shape, and size; and analyzed their polymer types using fourier transform infrared spectrometry. The abundances of MPs 100 μm to 5 mm in size were 2.0 ± 1.6 pieces/m² (13 polymer types) in Kusatsu, 19.7 ± 13.7 pieces/m² in Da Nang (14 types), and 12.5 ± 10.1 pieces/m² in Kathmandu (15 types). We classified the MPs into two groups; containers/packaging-MPs and rubber-MPs. Among all MPs, the containers/packaging-MPs accounted for 55 ± 5% of the polymer types composition. In contrast, the rubber-MPs accounted for 16 ± 6% of all MPs which were higher than those previously published for environmental water and sediment samples. The containers/packaging-MPs were fragments of various colors while most of the rubber-MPs were fragments or granules in black. The number-size distributions of MPs showed that the mode of formation explains the differences between their polymer types (tearing for containers/packaging-MPs and abrasion for rubber-MPs). In Da Nang and Kathmandu, the abundance of containers/packaging-MPs and rubber-MPs were correlated so that those MPs might be micronized from the originated materials in the sources with the similar composition (e.g. dump points). It was indicated that the characteristics of MPs pollution in surface road dust might be different depending on waste management practices.

Investigation of Ag and Cu Filament Formation Inside the Metal Sulfide Layer of an Atomic Switch Based on Point-Contact Spectroscopy

The atomic switches have attracted wide attention owing to their applications in nonvolatile electric devices. The atomic switch is operated by the formation and dissipation of a metallic filament inside a metal sulfide film, which is controlled by a solid electrochemical reaction. Although the metallic filament is considered to consist of metal atoms, the chemical species of the metallic filament are difficult to be identified due to challenges in observing the metallic filament inside the solid. In this study, we report the investigation on the metallic filament in the atomic switch with metal sulfide based on point-contact spectroscopy (PCS). By cooling the atomic switch, the switch voltage increased to 1 V, which allowed for the PCS measurement. The PCS revealed that the metallic filament was composed of Ag atoms in the case of the Pt/Ag₂S/Ag atomic switch. We applied this technique to the Pt/Cu₂S/Ag and Pt/Ag₂S/Cu atomic switches to uncover the formation process of the metallic filament. In both atomic switches, the chemical species of the metallic filament were Ag. The metal atoms were supplied from both the metal electrode and the sulfide layer.

Investigation on the formation process of metal atomic filament for metal sulfide atomic switches by electrical measurement

We have studied the formation process of the metal atomic filament for metal sulfide atomic switches by electrical measurement. The switching between ON and OFF states of the atomic switch is controlled by the application of the bias voltage for the atomic switches. The SET (OFF → ON) and RESET (ON → OFF) voltages were investigated for the atomic switch where the Ag₂S or Cu₂S layer were sandwiched between the Pt and Ag or Cu electrodes. The SET and RESET voltages of the Ag/Cu₂S/Pt and Cu/Ag₂S/Pt were close to those of the Ag/Ag₂S/Pt atomic switch, and different from those of the Cu/Cu₂S/Pt atomic switch. These results indicated that the dominant chemical species of the making and breaking part of the metal filament was Ag, and that the source of the metal filament was both the sulfide layer and the metal electrode.

In situ Raman monitoring of dielectric-heating-enhanced freeze-drying under different electromagnetic wave frequencies

We studied the effect of dielectric heating on the enhancement of freeze-drying by electromagnetic waves (EMWs) under different frequencies: 2.45 GHz microwaves (MWs), and 27 and 200 MHz radio frequencies (RFs). The irradiation with RFs, particularly at 27 MHz, reduced the duration of freeze-drying by 67%. We further analysed the water structure by in situ Raman spectroscopy during freeze-drying under EMWs. The phase transition from ice to water occurred soon after starting irradiation by MWs at 2.45 GHz, while the ice phase was almost maintained at an RF of 27 MHz.

We studied the effect of dielectric heating on the enhancement of freeze-drying by electromagnetic waves (EMWs) under different frequencies: 2.45 GHz microwaves (MWs), and 27 and 200 MHz radio frequencies (RFs).

Stretch dependent electronic structure and vibrational energy of the bipyridine single molecule junction

Change in the molecular orbital energy and vibrational energy of the bipyridine single molecule junction as a function of stretch distance.

Cross-country analysis of faecal sludge dewatering

Dewatering of faecal sludge (FS) is indispensable for adequate FS management. However, comprehensive knowledge is lacking on FS dewatering performance. This study compared the dewatering performance of FS from different countries and onsite sanitation technologies, to assess influential characteristics on dewatering, and to compare dewatering performance of FS with wastewater sludge. We collected 73 FS samples from septic tanks, lined pit latrines, unlined pit latrines and johkasou tanks in Uganda, Vietnam and Japan, and 18 samples of wastewater sludge in Switzerland. Capillary suction time (CST) and total solids (TS) of centrifuged sludge (%TS_final) were determined as metrics of dewatering rate and dewaterability, respectively, together with relevant sludge characteristics. Data were analysed by bootstrapping comparison of median results of each sample category and by bootstrapping multiple regression analysis to quantify the relative importance of sludge characteristics on dewatering performance. Results showed that the dewatering rate was significantly different between FS from different technologies, whereas dewaterability was significantly different within the same technology. FS had a significantly lower dewatering rate than wastewater sludge. In contrast, FS dewaterability was greater than wastewater sludge. However, this could be attributed to higher concentrations of sand in FS. Electrochemical properties such as NH₄-N and surface charge had the strongest correlation to dewatering rate, and solid properties such as sand content and total volatile solids to dewaterability. The results identify potential characteristics that could explain and predict the high variability of FS dewatering performance that is observed in the field.

High time-resolution simulation of E. coli on hands reveals large variation in microbial exposures amongst Vietnamese farmers using human excreta for agriculture

Infectious disease transmission is frequently mediated by the environment, where people's movements through and interactions with the environment dictate risks of infection and/or illness. Capturing these interactions, and quantifying their importance, offers important insights into effective interventions. In this study, we capture high time-resolution activity data for twenty-five Vietnamese farmers during collection and land application of human excreta for agriculture. Although human excreta use improves productivity, the use increases risks of enteric infections for both farmers and end users. In our study, the activity data are integrated with environmental microbial sampling data into a stochastic-mechanistic simulation of E. coli contamination on hands and E. coli ingested. Results from the study include frequent and variable contact rates for farmers' hands (from 34 to 1344 objects contacted per hour per hand), including highly variable hand-to-mouth contact rates (from 0 to 9 contacts per hour per hand). The frequency of hand-to-mouth contacts was substantially lower than the widely-used frequency previously reported for U.S. Office Workers. Environmental microbial contamination data highlighted ubiquitous E. coli contamination in the environment, including excreta, hands, toilet pit, handheld tools, soils, surfaces, and water. Results from the simulation suggest dynamic changes in E. coli contamination on hands, and wide variation in hand contamination and E. coli ingested amongst the farmers studied. Sensitivity analysis suggests that E. coli contamination on hands and ingested doses are most influenced by contamination of handheld tools, excreta, and the toilet pit as well as by frequency of hand-to-mouth contacts. The study findings are especially relevant given the context: no farmers reported adequate storage time of human excreta, and personal protective mask availability did not prevent hand-to-mouth contacts. Integrating high time-resolution activity data into exposure assessments highlights variation in exposures amongst farmers, and offers greater insight into effective interventions and their potential impacts.