Periodic chemical cleaning with urea: disintegration of biofilms and reduction of key biofilm-forming bacteria from reverse osmosis membranes.

Biofouling is one of the major factors causing decline in membrane performance in reverse osmosis (RO) plants, and perhaps the biggest hurdle of membrane technology. Chemical cleaning is periodically carried out at RO membrane installations aiming to restore membrane performance. Typical cleaning agents used in the water treatment industry include sodium hydroxide (NaOH) and hydrochloric acid (HCl) in sequence. Rapid biofilm regrowth and related membrane performance decline after conventional chemical cleaning is a routinely observed phenomenon due to the inefficient removal of biomass from membrane modules. Since extracellular polymeric substances (EPS) make up the strongest and predominant structural framework of biofilms, disintegration of the EPS matrix should be the main target for enhanced biomass removal. Previously, we demonstrated at lab-scale the use of concentrated urea as a chemical cleaning agent for RO membrane systems. The protein denaturation property of urea was exploited to solubilize the proteinaceous foulants, weakening the EPS layer, resulting in enhanced biomass solubilization and removal from RO membrane systems. In this work, we investigated the impact of repeated chemical cleaning cycles with urea/HCl as well as NaOH/HCl on biomass removal and the potential adaptation of the biofilm microbial community. Chemical cleaning with urea/HCl was consistently more effective than NaOH/HCl cleaning over 6 cleaning and regrowth cycles. At the end of the 6 cleaning cycles, the percent reduction was 35% and 41% in feed channel pressure drop, 50% and 70% in total organic carbon, 30% and 40% in EPS proteins, and 40% and 66% in the peak intensities of protein-like matter, after NaOH/HCl cleaning and Urea/HCl cleaning, respectively. 16S ribosomal RNA (rRNA) gene sequencing of the biofilm microbial community revealed that urea cleaning does not select for key biofouling families such as Sphingomonadaceae and Xanthomonadaceae that are known to survive conventional chemical cleaning and produce adhesive EPS. This study reaffirmed that urea possesses all the desirable properties of a chemical cleaning agent, i.e., it dissolves the existing fouling layer, delays fresh fouling accumulation by inhibiting the production of a more viscous EPS, does not cause damage to the membranes, is chemically stable, and environmentally friendly as it can be recycled for cleaning.

Deep Learning for Pediatric Posterior Fossa Tumor Detection and Classification: A Multi-Institutional Study.

BACKGROUND AND PURPOSE: Posterior fossa tumors are the most common pediatric brain tumors. MR imaging is key to tumor detection, diagnosis, and therapy guidance. We sought to develop an MR imaging-based deep learning model for posterior fossa tumor detection and tumor pathology classification. MATERIALS AND METHODS: The study cohort comprised 617 children (median age, 92 months; 56% males) from 5 pediatric institutions with posterior fossa tumors: diffuse midline glioma of the pons (n = 122), medulloblastoma (n = 272), pilocytic astrocytoma (n = 135), and ependymoma (n = 88). There were 199 controls. Tumor histology served as ground truth except for diffuse midline glioma of the pons, which was primarily diagnosed by MR imaging. A modified ResNeXt-50-32x4d architecture served as the backbone for a multitask classifier model, using T2-weighted MRIs as input to detect the presence of tumor and predict tumor class. Deep learning model performance was compared against that of 4 radiologists. RESULTS: Model tumor detection accuracy exceeded an AUROC of 0.99 and was similar to that of 4 radiologists. Model tumor classification accuracy was 92% with an F1 score of 0.80. The model was most accurate at predicting diffuse midline glioma of the pons, followed by pilocytic astrocytoma and medulloblastoma. Ependymoma prediction was the least accurate. Tumor type classification accuracy and F1 score were higher than those of 2 of the 4 radiologists. CONCLUSIONS: We present a multi-institutional deep learning model for pediatric posterior fossa tumor detection and classification with the potential to augment and improve the accuracy of radiologic diagnosis.

Study design of a stepped wedge cluster randomized controlled trial to evaluate the effect of a locally tailored approach for preconception care - the APROPOS-II study.

BACKGROUND: In a previous feasibility study (APROPOS) in a single municipality of the Netherlands, we showed that a locally tailored preconception care (PCC) approach has the potential to positively affect preconceptional lifestyle behaviours. Therefore, we designed a second study (APROPOS-II) to obtain a more robust body of evidence: a larger group of respondents, more municipalities, randomization, and a more comprehensive set of (clinical) outcomes. The aim of this study is to assess the effectiveness and the implementation process of a local PCC-approach on preconceptional lifestyle behaviours, health outcomes and the reach of PCC among prospective parents and healthcare providers. METHODS: This study is an effectiveness-implementation hybrid type 2 trial. This involves a stepped-wedge cluster randomized controlled trial design aiming to include over 2000 future parents from six municipalities in the Netherlands. The intervention has a dual-track approach, focusing on both the uptake of PCC among future parents and the provision of PCC by healthcare providers. The PCC-approach consists of 1) a social marketing strategy directed towards prospective parent(s) and 2) a local care pathway to improve interdisciplinary collaboration. Data will be collected before and after the introduction of the intervention through questionnaires and medical records in each of the participating municipalities. The primary outcome of this study is change in lifestyle behaviours (e.g. folic acid use, smoking and alcohol use). Secondary outcomes are pregnancy outcomes (e.g. miscarriage, preterm birth, gestational diabetes) and the uptake of PCC. Moreover, a process evaluation will be performed, providing information on the efficacy, feasibility, barriers and facilitators regarding the implementation of the intervention. DISCUSSION: The APROPOS-II study introduces a locally tailored PCC-approach in six municipalities in the Netherlands that will contribute to the body of evidence regarding the effectiveness of PCC and its implementation. If this intervention has a positive effect on lifestyle behaviour changes, leading to improved pregnancy outcomes and the future health of prospective parents and their offspring, it could subsequently be upscaled to (inter)national implementation. TRIAL REGISTRATION: Dutch Trial register: NL7784 (Registered June 6th, 2019).

Nutrient concentration in sediments accumulated in pre-treatment basins of urban LID technologies.

In this study, the contribution of pre-treatment basins of low impact development (LID) technologies to nutrient reduction performance was evaluated by understanding the distribution of nutrient in sediments accumulated in each system. The captured sediments were mostly silt to medium sand ranging from 9% to 92% of the sediments collected. Greater average N and P concentrations were found in silt particles amounting to 345 mg/kg and 696 mg/kg, respectively compared to sand and gravel. Although, N concentrations in accumulated sediments were found to be highly variable at different particle sizes (CV: 0.24 to 0.77) compared to P concentration (CV: 0.08 to 0.36) attributed to effective P treatment mechanism through deposition compared to complex nitrogen removal mechanisms. In addition, the difference between N and P concentrations of sediments collected in the pre-treatment basins of LID technologies and in-situ soil was attributed to the continuous pollutant input to the LID technologies during storm events. The study proved that pre-treatment basins of stormwater LID technologies reinforced the nutrient removal performances through sediment retention. The findings of this research may be used to design pre-treatment basins of LID technologies considering nutrients as a limiting factor.

Implications of CaCl2 application to plants in LID facilities.

Low impact development (LID) technologies mimic the natural water cycle through the physico-chemical and biological interactions of plants, filter media and soil, and microorganisms, thereby reducing the release of pollutants. In LID facilities, plants carry out photosynthesis, facilitate microbial growth, and uptake pollutants contained in stormwater runoff. However, de-icers (CaCl2) used to melt snow during winter slow the growth of plants and even increase plant mortality. In addition, de-icers change the soil structure, causing changes in soil content and affecting the growth of plants and microorganisms. Therefore, this study examined the effects of CaCl2 on the resistance of plants, the removal efficiency of non-point source pollutants, and water circulation. The mortality rate of the tree and shrubs caused by CaCl2 was found to be in the order of Rhododendron indicum > Spiraea prunifolia var. simpliciflora > Metasequoia glyptostroboides. For herbaceous plants, mortality rate was in the order of Pratia pedunculata > Aquilegia japonica > Tagetes erecta > Sedum makinoi aurea > Hosta longipes > Dianthus chinensis > Acorus gramineus > Liriope platyphylla. In addition, it was found that the amount of chlorophyll decreases with high concentrations of CaCl2. The findings of this research will be useful for plant selection considering CaCl2 concentrations applied to paved areas during the winter.

Microplastic in riverine fish is connected to species traits.

Microplastic is a contaminant of concern worldwide. Rivers are implicated as major pathways of microplastic transport to marine and lake ecosystems, and microplastic ingestion by freshwater biota is a risk associated with microplastic contamination, but there is little research on microplastic ecology within freshwater ecosystems. Microplastic uptake by fish is likely affected by environmental microplastic abundance and aspects of fish ecology, but these relationships have rarely been addressed. We measured the abundance and composition of microplastic in fish and surface waters from 3 major tributaries of Lake Michigan, USA. Microplastic was detected in fish and surface waters from all 3 sites, but there was no correlation between microplastic concentrations in fish and surface waters. Rather, there was a significant effect of functional feeding group on microplastic concentration in fish. Neogobius melanostomus (round goby, a zoobenthivore) had the highest concentration of gut microplastic (19 particles fish-1) compared to 10 other fish taxa measured, and had a positive linear relationship between body size and number of microplastic particles. Surface water microplastic concentrations were lowest in the most northern, forested watershed, and highest in the most southern, agriculturally dominated watershed. Results suggest microplastic pollution is common in river food webs and is connected to species feeding characteristics. Future research should focus on understanding the movement of microplastic from point-source and diffuse sources and into aquatic ecosystems, which will support pollution management efforts on inland waters.

A new psychometric questionnaire for reporting of somatosensory percepts.

OBJECTIVE: There have been remarkable advances over the past decade in neural prostheses to restore lost motor function. However, restoration of somatosensory feedback, which is essential for fine motor control and user acceptance, has lagged behind. With an increasing interest in using electrical stimulation to restore somatosensory sensations within the peripheral (PNS) and central nervous systems (CNS), it is critical to characterize the percepts evoked by electrical stimulation in a standardized manner with a validated psychometric questionnaire. This will allow comparison of results from applications at various nervous system levels in multiple settings. APPROACH: We compiled a summary of published reports of somatosensory percepts that were elicited by electrical stimulation in humans and used these to develop a new psychometric questionnaire. RESULTS: This new questionnaire was able to characterize subjective evoked sensations with good test-retest reliability (Spearman's correlation coefficients ranging 0.716 ⩽ ρ ⩽ 1.000, p ⩽ 0.005) in 13 subjects receiving stimulation through neural implants in both the CNS and PNS. Furthermore, the new questionnaire captured more descriptors (M = 2.65, SD = 0.91) that would have been missed by being categorized as 'other sensations', using a previous questionnaire (M = 1.40, SD = 0.77, t(12) = -10.24, p < 0.001). Lastly, the new questionnaire was able to capture different descriptors within subjects using different patterns of electrical stimulation (Wilk's Lambda = 0.42, F(3, 10) = 4.58, p = 0.029). SIGNIFICANCE: This new somatosensory psychometric questionnaire will aid in establishing consistency and standardization of reporting in future studies of somatosensory neural prostheses.

Oxygen therapy for acutely ill medical patients: a clinical practice guideline

What is the best way to use oxygen therapy for patients with an acute medical illness? A systematic review published in the Lancet in April 2018 found that supplemental oxygen in inpatients with normal oxygen saturation increases mortality.1 Its authors concluded that oxygen should be administered conservatively, but they did not make specific recommendations on how to do it. An international expert panel used that review to inform this guideline. It aims to promptly and transparently translate potentially practice-changing evidence to usable recommendations for clinicians and patients.2 The panel used the GRADE framework and following standards for trustworthy guidelines.3

Anatomical Retzius-space preservation is associated with lower incidence of postoperative inguinal hernia development after robot-assisted radical prostatectomy.

BACKGROUND: Postoperative inguinal hernia (IH) is a non-negligible sequelae with a wide array of rates after robot-assisted laparoscopic radical prostatectomy (RALP). Our aim was to evaluate the incidence and risk factors of postoperative IH development in men undergoing RALP. METHODS: A retrospective analysis of 839 patients "541 of conventional-RALP (C-RALP), and 298 of Retzius sparing-RALP (RS-RALP)" received treatment of prostate cancer between 2005 and 2016 and met with our inclusion criteria was performed. Primary endpoint was incidence of IH after RALP, while secondary endpoint was to assess risk factors of IH occurrence. RESULTS: Overall incidence of postoperative IH was 6.3% (53 out of 839). Mean follow-up period and median time of IH development were 24.1 and 14.0 months, respectively. Among patients who developed IH, there was a higher incidence in C-RALP compared to RS-RALP, (79.2 vs 20.8%, respectively, P = 0.02). Multivariate analysis showed that BMI group (HR 0.471, P = 0.023) and C-RALP (HR 2.834, P = 0.002) were significant predictors of IH development. Kaplan-Meier curve showed that 3-year IH-disease progression free rate was significantly higher after RS-RALP compared to C-RALP (94.2 vs 71.6%, respectively, P < 0.001), likewise in obese versus non-obese patients (87.7 vs 76.6%, respectively, P < 0.003). CONCLUSION: Our study showed that overall incidence of IH was 6.3% after RALP. Nevertheless, RS-RALP carries a lower incidence of IH after surgery, while C-RALP and low BMI are predictors of IH development.

Comparison of the treatment performance of hybrid constructed wetlands treating stormwater runoff.

This study was conducted to compare the treatment performance of two hybrid constructed wetlands (CWs) in treating stormwater runoff. The hybrid CWs were composed of a combination of free water surface (FWS) and horizontal subsurface flow (HSSF) CWs. Based on the results, strong correlation exists between potential runoff impacts and stormwater characteristics; however, the low correlations also suggest that not only the monitored parameters contribute to stormwater event mean concentrations (EMC) of pollutants, but other factors should also be considered as well. In the hydraulic and treatment performance of the hybrid CWs, a small surface area to catchment area (SA/CA) ratio, receiving a high concentration of influent EMC, will find it hard to achieve great removal efficiency; also a large SA/CA ratio, receiving low concentration of influent EMC, will find it hard to achieve great removal efficiency. With this, SA/CA ratio and influent characteristics such as EMC or load should be considered among the design factors of CWs. The performance data of the two CWs were used to consider the most cost-effective design of a hybrid CW. The optimum facility capacity (ratio of total runoff volume to storage volume) that is applicable for a target volume reduction and removal efficiency was provided in this study.

Physical design optimization of an urban runoff treatment system using Stormwater Management Model (SWMM).

The study presented the application of Stormwater Management Model (SWMM) in determining the optimal physical design properties of an established low impact development (LID) system treating road runoff. The calibration of the model was based on monitored storm events occurring from May 2010 to July 2013. It was found that the total suspended solids was highly correlated with stormwater runoff volume and dominant heavy metal constituents in stormwater runoff, such lead, zinc and copper, with a Pearson correlation coefficient ranging from 0.88 to 0.95 (P<0.05). Reducing the original ratio of the storage volume to surface area (SV/SA) of the facility and depth by 25% could match the satisfactory performance efficiency achieved in the original design. The smaller SV/SA and depth would mean a less costly system, signifying the importance of optimization in designing LID systems.

Genetic variants of IL-11 associated with risk of Hirschsprung disease.

BACKGROUND: Hirschsprung disease (HSCR) is a congenital and heterogeneous disorder characterized by the absence of enteric ganglia during enteric nervous system (ENS) development. Our recent genome-wide association study has identified a variant (rs6509940) of interleukin-11 (IL-11) as a potential susceptible locus for HSCR. As interleukins play important roles in the ENS, we further studied associations with HSCR of nine common single nucleotide polymorphisms (SNPs) on IL-11. METHODS: Biopsy specimens or surgical materials from all patients that were tested for histological examination based on the absence of the enteric ganglia were collected. A total of nine SNPs on IL-11 were genotyped in 187 HSCR patients and 283 unaffected controls using TaqMan genotyping assay. KEY RESULTS: Combined analysis revealed that several SNPs (minimum p = 1.57 × 10(-7) ) showed statistically significant associations with HSCR, even after Bonferroni correction (pcorr  = 1.73 × 10(-6) for the SNP). Moreover, the most common haplotype was strongly associated with HSCR (pcorr  = 2.20 × 10(-6) ). In further analysis among three HSCR subtypes (short segment, S-HSCR; long segment, L-HSCR; total colonic aganglionosis, TCA) based on the extent of aganglionic segment, the result showed a different association pattern depending on the subtypes (minimum pcorr  = 6.12 × 10(-5) for rs6509940 in S-HSCR; but no significant SNP in L-HSCR and TCA). CONCLUSIONS & INFERENCES: Although further replication in a larger cohort and functional evaluations are needed, our findings suggest that genetic variations of IL-11 may be associated with the risk of HSCR and/or the mechanisms related to ENS development.

Treatment of suspended solids and heavy metals from urban stormwater runoff by a tree box filter.

Particulates, inorganic and toxic constituents are the most common pollutants associated with urban stormwater runoff. Heavy metals such as chromium, nickel, copper, zinc, cadmium and lead are found to be in high concentration on paved roads or parking lots due to vehicle emissions. In order to control the rapid increase of pollutant loads in stormwater runoff, the Korean Ministry of Environment proposed the utilization of low impact developments. One of these was the application of tree box filters that act as a bioretention treatment system which executes filtration and sorption processes. In this study, a tree box filter located adjacent to an impervious parking lot was developed to treat suspended solids and heavy metal concentrations from urban stormwater runoff. In total, 11 storm events were monitored from July 2010 to August 2012. The results showed that the tree box filter was highly effective in removing particulates (up to 95%) and heavy metals (at least 70%) from the urban stormwater runoff. Furthermore, the tree box filter was capable of reducing the volume runoff by 40% at a hydraulic loading rate of 1 m/day and below.

No association between CCL2 gene polymorphisms and risk of inflammatory demyelinating diseases in a Korean population.

Inflammatory demyelinating disease (IDD), which includes multiple sclerosis (MS) and neuromyelitis optica (NMO), affects the central nervous system. Chemokine ligand 2 (CCL2/MCP-1) is considered an important contributor to the development or progression of IDD. However, genetic association studies of Asian populations are lacking. In this study, we investigated a possible association between CCL2 polymorphisms (rs1024611, rs28730833, and rs2857657) and a Korean population (178 IDD patients and 237 healthy controls) using multiple logistic regression models. However, we did not find any association, which was consistent with other studies in Caucasian populations. In conclusion, our results suggest that CCL2 variants may not contribute to the pathogenesis of IDD.

Development of discrimination SNP markers for Hanwoo (Korean native cattle).

In the Korean meat market, the native cattle, Hanwoo beef, are preferred over imported beef and domestic Holstein beef despite its relatively high price. In order to hold the beef industry accountable and support consumers' right to know, correct beef-origin labeling is required. For this purpose, we developed 90 single-nucleotide polymorphism markers to discriminate between Hanwoo and other breeds including Holstein using 1602 cattle DNAs. The probability of discrimination was found to be 100% in a subsequent validation set consisting of 632 DNAs. Our study suggests that improved beef-origin discrimination can be achieved by using a combined genetic model that takes into account small genetic differences among a large number of markers. These markers could be useful for discriminating between Hanwoo and imported breeds including domestic Holsteins, and would contribute to the prevention of falsified beef origin.

Seasonal nutrient uptake of plant biomass in a constructed wetland treating piggery wastewater effluent.

The surface-flow constructed wetland (CW) located in Nonsan City, South Korea, and constructed as the final stage of a piggery wastewater treatment plant that aims to treat high nutrient content effluent during dry days and stormwater runoff during wet days was monitored from October 2008 to November 2011. This research investigated the seasonal nutrient uptake of plant biomass in the CW and nutrient concentration changes in each treatment region under monsoon and temperate climate conditions. Results showed that the mean total nitrogen removal during summer (June to August) was higher by 13% than in spring (March to May), while total phosphorus removal was higher by 22% in fall (September to November) than in winter (December to February). All plants in the CW reached their maximum biomass coverage and weight in summer and minimum growth in winter. The highest N and P content in plants occurred in September with 583.2 g/m(2) and August with 62.0 g/m(2), respectively. Based on the results, it is recommended that the harvesting of plants should be conducted during the time of the peak nutrient uptake and before the plants release the nutrient content back to the CW. The dependence of nutrient removal efficiency on plants is not so significant. In order to increase the nutrient removal rate by plant uptake, it is suggested that the treatment regions in the CW be covered by plants.

Development of a horizontal subsurface flow modular constructed wetland for urban runoff treatment.

Constructed wetlands (CWs) are well recognized as having low construction and maintenance cost and low energy requirement. However, CW design has been mainly based on rule-of-thumb approaches. In this study, the efficiency of a modular horizontal subsurface flow (HSSF) CW using four different design schemes was investigated. Based on the results, the four systems have attained more than 90% removal of total suspended solids and more than 50% removal efficiency for total phosphorus, PO(4)-P and Zn. The planted system achieved higher pollutant removal rates than the unplanted system. In terms of media, bottom ash was more effective than woodchip in reducing the pollutants. Considering the flow length, optimum removal efficiency was achieved after passing the sedimentation tank and vertical media layer; with respect to depth, more pollutants were removed in the upper sand layer than in the lower gravel layer. This study recommended a surface area of 0.25 to 0.8% of catchment area for planted CW and 0.26 to 0.9% for unplanted CW using the 7.5 to 10 mm design rainfall.

Phosphorus mass balance in a surface flow constructed wetland receiving piggery wastewater effluent.

This research was conducted to investigate the phosphorus forms present in water, soil and sediment and to estimate the phosphorus mass balance in a surface flow constructed wetland (CW). Water quality and sediment samples were collected from each cell along the hydrologic path in the CW from October 2008 to December 2010. At the same time, three dominant plant species (e.g. common reed and cattails) were observed through the measurement of the weight, height and phosphorus content. Based on the results, the orthophosphate constituted 24-34% of total phosphorus in water for each cell. The overall average phosphorus removal efficiency of the CW was approximately 38%. The average inflow and outflow phosphorus loads during the monitoring period were 1,167 kg/yr and 408 kg/yr, respectively. The average phosphorus retention rate was 65%, was mainly contributed by the settling of TP into the bottom sediments (30%). The phosphorus uptake of plants was less than 1%. The estimated phosphorus mass balance was effective in predicting the phosphorus retention and release in the CW treating wastewater. Continuous monitoring is underway to support further assessment of the CW system and design.

System design and treatment efficiency of a surface flow constructed wetland receiving runoff impacted stream water.

This study reported the efficiency of a free water surface flow constructed wetland (CW) system that receives runoff impacted stream water from a forested and agricultural watershed. Investigations were conducted to examine the potential effect of hydraulic fluctuations on the CW as a result of storm events and the changes in water quality along the flow path of the CW. Based on the results, the incoming pollutant concentrations were increased during storm events and greater at the near end of the storm than at the initial time of storm. A similar trend was observed to the concentrations exiting the CW due to the wetland being a relatively small percentage of the watershed (<0.1%) that allowed delays in runoff time during storm events. The concentrations of most pollutants were significantly reduced (p < 0.05) except for nitrate (p = 0.5). Overall, this study suggests that the design of the system could feasibly function for the retention of most pollutants during storm events as the actual water quality of the outflow was significantly better by 21-71% than the inflow and the levels of pollutants were reduced to appreciable levels.

Treatment performance of a constructed wetland during storm and non-storm events in Korea.

The efficiency of a free water surface flow constructed wetland (CW) in treating agricultural discharges from stream was investigated during storm and non-storm events between April and December, 2009. Physico-chemical and water quality constituents were monitored at five sampling locations along the flow path of the CW. The greatest reduction in pollutant concentration was observed after passing the sedimentation zone at approximately 4% fractional distance from the inflow. The inflow hydraulic loading, flow rates and pollutant concentrations were significantly higher and variable during storm events than non-storm (baseflow) condition (p <0.001) that resulted to an increase in the average pollutant removal efficiencies by 10 to 35%. The highest removal percentages were attained for phosphate (51 ± 22%), ammonium (44 ± 21%) and phosphorus (38 ± 19%) while nitrate was least effectively retained by the system with only 25 ± 17% removal during non-storm events. The efficiency of the system was most favorable when the temperature was above 15 °C (i.e., almost year-round except the winter months) and during storm events. Overall, the outflow water quality was better than the inflow water quality signifying the potential of the constructed wetland as a treatment system and capability of improving the stream water quality.