On-site filtration of large sample volumes improves the detection of opportunistic pathogens in drinking water distribution systems.

In this study, we compared conventional vacuum filtration of small volumes through disc membranes (effective sample volumes for potable water: 0.3-1.0 L) with filtration of high volumes using ultrafiltration (UF) modules (effective sample volumes for potable water: 10.6-84.5 L) for collecting bacterial biomass from raw, finished, and tap water at seven drinking water systems. Total bacteria, Legionella spp., Legionella pneumophila, Mycobacterium spp., and Mycobacterium avium complex in these samples were enumerated using both conventional quantitative PCR (qPCR) and viability qPCR (using propidium monoazide). In addition, PCR-amplified gene fragments were sequenced for microbial community analysis. The frequency of detection (FOD) of Legionella spp. in finished and tap water samples was much greater using UF modules (83% and 77%, respectively) than disc filters (24% and 33%, respectively). The FODs for Mycobacterium spp. in raw, finished, and tap water samples were also consistently greater using UF modules than disc filters. Furthermore, the number of observed operational taxonomic units and diversity index values for finished and tap water samples were often substantially greater when using UF modules as compared to disc filters. Conventional and viability qPCR yielded similar results, suggesting that membrane-compromised cells represented a minor fraction of total bacterial biomass. In conclusion, our research demonstrates that large-volume filtration using UF modules improved the detection of opportunistic pathogens at the low concentrations typically found in public drinking water systems and that the majority of bacteria in these systems appear to be viable in spite of disinfection with free chlorine and/or chloramine.IMPORTANCEOpportunistic pathogens, such as Legionella pneumophila, are a growing public health concern. In this study, we compared sample collection and enumeration methods on raw, finished, and tap water at seven water systems throughout the State of Minnesota, USA. The results showed that on-site filtration of large water volumes (i.e., 500-1,000 L) using ultrafiltration membrane modules improved the frequency of detection of relatively rare organisms, including opportunistic pathogens, compared to the common approach of filtering about 1 L using disc membranes. Furthermore, results from viability quantitative PCR (qPCR) with propidium monoazide were similar to conventional qPCR, suggesting that membrane-compromised cells represent an insignificant fraction of microorganisms. Results from these ultrafiltration membrane modules should lead to a better understanding of the microbial ecology of drinking water distribution systems and their potential to inoculate premise plumbing systems with opportunistic pathogens where conditions are more favorable for their growth.

Senescent tumor cells in colorectal cancer are characterized by elevated enzymatic activity of complexes 1 and 2 in oxidative phosphorylation.

BACKGROUND: Cellular senescence is defined as an irreversible cell cycle arrest caused by various internal and external insults. While the metabolic dysfunction of senescent cells in normal tissue is relatively well-established, there is a lack of information regarding the metabolic features of senescent tumor cells. METHODS: Publicly available single-cell RNA-sequencing data from the GSE166555 and GSE178341 datasets were utilized to investigate the metabolic features of senescent tumor cells. To validate the single-cell RNA-sequencing data, we performed senescence-associated ß-galactosidase (SA-ß-Gal) staining to identify senescent tumor cells in fresh frozen colorectal cancer tissue. We also evaluated nicotinamide adenine dinucleotide dehydrogenase-tetrazolium reductase (NADH-TR) and succinate dehydrogenase (SDH) activity using enzyme histochemical methods and compared the staining with SA-ß-Gal staining. MTT assay was performed to reveal the complex 1 activity of the respiratory chain in in-vitro senescence model. RESULTS: Single-cell RNA-sequencing data revealed an upregulation in the activity of complexes 1 and 2 in oxidative phosphorylation, despite overall mitochondrial dysfunction in senescent tumor cells. Both SA-ß-Gal and enzyme histochemical staining using fresh frozen colorectal cancer tissues indicated a high correlation between SA-ß-Gal positivity and NADH-TR/SDH staining positivity. MTT assay showed that senescent colorectal cancer cells exhibit higher absorbance in 600 nm wavelength. CONCLUSIONS: Senescent tumor cells exhibit distinct metabolic features, characterized by upregulation of complexes 1 and 2 in the oxidative phosphorylation pathway. NADH-TR and SDH staining represent efficient methods for detecting senescent tumor cells in colorectal cancer.

Incidence of and Influencing Factors for Arm Lymphedema After Salvage Treatment for an Isolated Locoregional Recurrence of Breast Cancer.

PURPOSE: Data on subsequent arm lymphedema (SAL) after salvage treatment for locoregional recurrence (LRR) of breast cancer are limited. We conducted a study to evaluate the risk of SAL in patients with LRR. METHODS: We reviewed the data of patients with breast cancer who had LRR and were initially diagnosed between January 2003 and December 2017. Among the 214 patients who received curative salvage treatment, most had local (n = 125, 57.9%), followed by regional (n = 73, 34.1%), and locoregional (n = 16, 7.9%) recurrences. A competing risk analysis considering the factors of death and a second LRR were performed to exclude potential malignant lymphedema. We used the Fine-Gray subdistribution hazards model to estimate the hazard ratio (HR) for comparing the risk of SAL. RESULTS: With a median follow-up duration of 41.4 months (interquartile range, 25.6-65.1), 51 patients (23.8%) experienced SAL with a median interval of 9.9 months after treatment. The two-year cumulative incidence of SAL was 12.7%. Among the 18 patients with initial lymphedema, nine (50.0%) developed SAL. Multivariate analysis revealed that a history of lymphedema (HR, 4.61; p < 0.001) and taxane-based salvage chemotherapy (HR, 2.38; p = 0.009) were significantly associated with SAL development. CONCLUSION: Salvage treatment for LRR-induced SAL was performed in 24% of the patients. A history of initial lymphedema and salvage taxane-based chemotherapy increases the risk of developing SAL. Therefore, close surveillance for the incidence of SAL is required in patients opting for salvage treatment for LRR.

Flushing Temporarily Improves Microbiological Water Quality for Buildings Supplied with Chloraminated Surface Water but Has Little Effect for Groundwater Supplies.

Microbial communities in premise plumbing systems were investigated after more than 2 months of long-term stagnation, during a subsequent flushing event, and during post-flush stagnation. Water samples were collected from showers in buildings supplied with chlorinated groundwater, untreated groundwater, and chloraminated surface water. The building supplied with chlorinated groundwater generally had the lowest bacterial concentrations across all sites (ranging from below quantification limit to 5.2 log copies/L). For buildings supplied with untreated groundwater, bacterial concentrations (5.0 to 7.6 log copies/L) and microbial community diversity index (ACE) values were consistent throughout sampling. Nontuberculous mycobacteria (NTM) and Legionella pneumophila were not detected in any groundwater-supplied buildings. Total bacteria, Legionella spp., and NTM were abundant in the surface water-supplied buildings following long-term stagnation (up to 7.6, 6.2, and 7.6 log copies/L, respectively). Flushing decreased these concentrations by ∼1 to >4 log units and reduced microbial community diversity, but the communities largely recovered within a week of post-flush stagnation. The results suggest that buildings supplied with disinfected surface water are more likely than buildings supplied with treated or untreated groundwater to experience deleterious changes in microbiological water quality during stagnation and that the water quality improvements from flushing with chloraminated water, while substantial, are short-lived.

Impact of COVID-19 infection on sports performance of elite university athletes.

BACKGROUND: Cardiopulmonary functions of athletes can be affected by the Coronavirus disease 2019 (COVID-19). This study aimed to investigate athletes' pattern of returning to sports after COVID-19, their experience of COVID-19-associated symptoms, and the disturbance in sports performance caused by the symptoms. METHODS: Elite university athletes who were infected with COVID-19 in 2022 were recruited for the survey and the data for 226 respondents were analyzed. Information about COVID-19 infection and the degree of disturbance in ordinary training and competition was collected. Their returning pattern to sports, the prevalence of COVID-19 symptoms, the degree of disturbance in sports by related symptoms, and factors associated with disturbance in sports and fatigue were analyzed. RESULTS: Results showed that 53.5% of the analyzed athletes returned to ordinary training immediately after quarantine, while 61.5% experienced disturbance in ordinary training, and 30.9% experienced that in competition. Most prevalent COVID-19 symptoms were lack of energy, easy fatiguability and cough. Disturbance in ordinary training and competition were mainly related to generalized, cardiologic, and respiratory symptoms. Women and those with severe and generalized symptoms had significantly higher odds of experiencing disturbance in training. Those with cognitive symptoms had higher odds of being "fatigue case." CONCLUSIONS: More than half of the athletes returned immediately to sports after the legal quarantine period of COVID-19 infection and experienced disturbance in ordinary training by related symptoms. Prevalent COVID-19 symptoms and the associated factors causing disturbance in sports and fatigue case were also revealed. This study will be helpful to establish the safe return guidelines essential for athletes after COVID-19.

Multi-scale Investigation of Ammonia-Oxidizing Microorganisms in Biofilters Used for Drinking Water Treatment.

Ammonia-oxidizing microorganisms (AOMs) include ammonia-oxidizing bacteria (AOB), archaea (AOA), and Nitrospira spp. sublineage II capable of complete ammonia oxidation (comammox). These organisms can affect water quality not only by oxidizing ammonia to nitrite (or nitrate) but also by cometabolically degrading trace organic contaminants. In this study, the abundance and composition of AOM communities were investigated in full-scale biofilters at 14 facilities across North America and in pilot-scale biofilters operated for 18 months at a full-scale water treatment plant. In general, the relative abundance of AOM in most full-scale biofilters and in the pilot-scale biofilters was as follows: AOB > comammox Nitrospira > AOA. The abundance of AOB in the pilot-scale biofilters increased with increasing influent ammonia concentration and decreasing temperature, whereas AOA and comammox Nitrospira exhibited no correlations with these parameters. The biofilters affected AOM abundance in the water passing through the filters via collecting and shedding but exhibited a minor influence on the composition of AOB and Nitrospira sublineage II communities in the filtrate. Overall, this study highlights the relative importance of AOB and comammox Nitrospira compared to AOA in biofilters and the influence of filter influent water quality on AOM in biofilters and their release into the filtrate.

Comparison of scapular position in elite tennis players with and without shoulder impingement: A case-control study.

BACKGROUND: To maximize the ball velocity in the tennis sever, the shoulder plays a key role in the kinetic chain. But shoulder inefficiency leads to shoulder injuries such as shoulder impingement syndrome (SIS). Thus, to verify the scapular movements during the tennis serve could help prevent shoulder injury in tennis players. OBJECTIVE: This case-control study aimed to verify the scapular movements during flat first serve for elite tennis players with shoulder impingement syndrome compared to those without it. METHODS: Eight elite tennis players (4 males and 4 females) with SIS and 8 elite healthy players (4 males and 4 females) performed flat first serves, and the three-dimensional scapular kinematic data was recorded using the Qualisys motion capture system through spherical reflective markers including the acromion marker cluster. RESULTS: The scapula was more internally rotated (median difference: 10.40∘) in the male players with SIS than in those without it at the maximally externally rotated humerothoracic joint during flat first serve, and female players with SIS (median difference: 7.16∘ and 11.28∘, respectively) had more internally rotated scapula at the maximally externally rotated humerothoracic joint and ball impact. CONCLUSION: Increased scapular internal rotation may be something that affects shoulder injuries in the overhead sports, and it may help to prevent and rehabilitate overhead injuries including SIS.

Lactoferrin-derived chimeric peptide (LFch) strongly boosts TGFß1-mediated inducible Treg differentiation possibly through downregulating TCR/CD28 signalling.

We recently reported that lactoferrin (LF) induces Foxp3+ Treg differentiation through binding to TGFß receptor III (TßRIII), and this activity was further enhanced by TGFß1. Generally, a low T-cell receptor (TCR) signal strength is favourable for Foxp3+ Treg differentiation. In the present study, we explored the effect of lactoferrin chimera (LFch, containing lactoferricin [aa 17-30] and lactoferrampin [aa 265-284]), along with TGFß1 on Foxp3+ Treg differentiation. LFch alone did not induce Foxp3 expression, yet LFch dramatically enhanced TGFß1-induced Foxp3 expression. LFch had little effect on the phosphorylation of Smad3, a canonical transcriptional factor of TGFß1. Instead, LFch attenuated the phosphorylation of S6 (a target of mTOR), IκB and PI3K. These activities of LFch were completely abrogated by pretreatment of LFch with soluble TGFß1 receptor III (sTßRIII). Consistent with this, the activity of LFch on TGFß1-induced Foxp3 expression was also abrogated by treatment with sTßRIII. Finally, the TGFß1/LFch-induced T cell population substantially suppressed the proliferation of responder CD4+ T cells. These results indicate that LFch robustly enhances TGFß1-induced Foxp3+ Treg differentiation by diminishing TCR/CD28 signal intensity.

Selection of Safe Donors for Living Donor Liver Transplant Using Extended Right Lobe Graft.

Extended right lobectomy (ERL) for living donor liver transplant (LDLT) is selectively performed in many transplant centers and has shown excellent recipient outcomes as reported in previous studies. Yet, there is no universally accepted indication for ERL in respect to donor safety. Current study was designed to stratify risk factors of adverse donor outcome after ERL. A total of 79 living donors who underwent ERL for LDLT were included in analysis. Donors were classified as safety and hazard donor groups according to postoperative findings relevant to posthepatectomy liver failure classification by the International Study Group for Liver Surgery. On multivariable analysis, left lateral section volume <20% of total liver volume and nonpreservation of segment 4a venous drainage were the independent risk factors impairing postoperative outcomes. Despite the short-term impairment of liver function in hazard donor groups, all donors recovered and showed satisfactory remnant liver regeneration. However, these findings have implications in establishing selection criteria of donors eligible for ERL donation. In conclusion, LDLT using ERL graft can be safely performed provided so that left lateral section volume/total donor liver is ≥20% besides conventional donor selection criteria. Also, efforts to preserve segment 4a vein must be made in performing ERL graft procurement in LDLT donors.

Usefulness of hand grip strength to estimate other physical fitness parameters in older adults.

This study aimed to reveal the status of physical fitness (PF) levels and determine whether hand grip strength (HGS) could be used to estimate other PF parameters in older adults from large population data. A total of 46,269 participants aged ≥ 65 years who participated in the 2019 National Fitness Award Project in South Korea were included in the analysis. Of the participants, 6.8% had the highest level of overall physical fitness, while 48.9% had the lowest level. The proportion of overall PF levels differed significantly according to age groups. Significant associations between HGS and other PF parameters (30-s chair stand test, 2-min or 6-min walk test, sit-and-reach test, 3-m backwards walk test, and Figure-of-8 walk test) were noted and the group with low HGS (< 28 kg for men and < 18 kg for women) had significantly higher odds of having the lowest level of overall PF (odds ratio: 5.232 in men and 6.351 in women), after adjusting for age and body mass index. HGS could estimate muscular strength and endurance, aerobic fitness, flexibility, balance skills, and coordination skills, as well as overall PF level in older adults, and could be used as a substitute test for their PF level in limited situations.

The short-term effectiveness of scapular focused taping on scapular movement in tennis players with shoulder pain: A within-subject comparison.

This study aimed to investigate the short-term effectiveness of scapular focused taping (SFT) on scapular position and kinematics during the tennis serve among professional players with and without shoulder pain. The cohort included 7 players who had no history of non-shoulder pain (NSP) and 6 players with shoulder pain (SP). All participants performed tennis flat serves while the Qualisys motion capture system recorded three-dimensional scapular kinematic data according to the International Society of Biomechanics recommendations. SFT was applied to the participants' torso aligned with the lower trapezius, and the same movements were repeated. In the SP group, the scapula was tilted more posteriorly after the application of SFT as compared to before at ball release and maximally externally rotated humerothoracic joint during tennis serve (t = -5.081, P = .004 and t = -2.623, P = .047, respectively). In the NSP group, the scapula was tilted more posteriorly with SFT as compared to without at first 75% timing of the cocking phase and maximally externally rotated humerothoracic joint (t = -3.733, P = .010 and t = -2.510, P = .046, respectively). And the SP group exhibited a more rotated scapula externally after the application of SFT as compared to before at Ball impact (t = 5.283, P = .003). SFT had a positive immediate effect on the scapular posterior tilting and external rotation during certain phases of the tennis serve among tennis athletes with and without shoulder pain. These findings may help clinicians and sports practitioners to prevent and rehabilitate shoulder injuries for overhead athletes. Level of evidence: Level III; Case-Control Design; Comparative Study.

Photo-Regeneration of Zeolite-Based Volatile Organic Compound Filters Enabled by TiO2 Photocatalyst.

Indoor air filtration received significant attention owing to the growing threat to the environment and human health caused by air pollutants such as volatile organic compound (VOC) gases. However, owing to the limited adsorption capacity of VOC adsorbents, such as activated carbon, a rapid breakthrough can occur, reducing the service life of the filter. Therefore, TiO2-coated zeolite (TiO2/zeolite) was utilized as a photo-regenerative VOC adsorbent to increase the service life of VOC filters. In particular, with photoactive TiO2 forms on zeolite, efficient and repetitive photo-regeneration is attainable through the dissociation of VOC molecules by the photocatalytic reaction. We optimized the TiO2 coating amount to obtain TiO2/zeolite particles with a high surface area (BET surface area > 500 m2/g) and high adsorption capacity. A VOC filter with an adsorption efficiency of 72.1% for formaldehyde was realized using TiO2/zeolite as the adsorbent. Furthermore, the TiO2/zeolite filter exhibits a photo-regeneration efficiency of >90% for the initial two regeneration cycles using ultraviolet illumination, and >60% up to five cycles. Based on these observations, we consider that TiO2/zeolite is a potential adsorbent candidate for photo-regenerative VOC filters.

Incidence, mortality, and survival of liver cancer using Korea central cancer registry database: 1999-2019.

Backgrounds/Aims: Historically, incidence and survival analysis and annual traits for primary liver cancer (LC) has not been investigated in a population-based study in Korea. The purpose of the current study is to determine incidence, survival rate of patients with primary LC in Korea. Methods: We conducted a retrospective cohort study using Korea Central Cancer Registry based on the Korea National Cancer Incidence Database. Statistical analysis including crude rate and age-standadized rate (ASR) of incidence and mortality was performed for LC patients registered with C22 code in International Classification of Diseases, tenth revision from 1999 to 2019. Subgroup analysis was performed for hepatocellular carcinoma (HCC, C22.0) and intrahepatic cholangiocarcinoma (IHCC, C22.1). Results: The crude incidence rate of HCC (21.0 to 22.8 per 100,000) and IHCC (2.3 to 5.6 per 100,000) increased in the observed period from 1999 to 2019. The ASR decreased in HCC (20.7 to 11.9 per 100,000) but remained unchanged in IHCC (2.4 to 2.7 per 100,000). The proportion of HCC patients diagnosed in early stages (localized or regional Surveillance, Epidemiology, and End Results or SEER stage) increased significantly over time. As expected, 5-yeat survival rate of HCC was greatly improved, reaching 42.4% in the period between 2013 and 2019. This trait was more prominent in localized SEER stage. On the other hand, the proportion of IHCC patients diagnosed in localized stage remained unchanged (22.9% between 2013 and 2019), although ASR and 5-year survival rate showed minor improvements. Conclusions: A great improvement in survival rate was observed in patients with newly diagnosed HCCs. It was estimated to be due to an increase in early detection rate. On the contrary, detection rate of an early IHCC was stagnant with a minor improvement in prognosis.

Systemic Immune-Inflammatory Marker of High Meld Patients Is Associated With Early Mortality After Liver Transplantation.

The scarcity of deceased donor livers has led to allocation of grafts to only the most seriously ill patients with a high Model for End-Stage Liver Disease (MELD) score, which has resulted in a high mortality rate after deceased donor liver transplantation (DDLT). The aim of this study is to identify risk factors for posttransplant mortality and thereby reduce futile outcomes in DDLT. Between 2013 and 2019, 57 recipients with MELD scores ≥30 underwent DDLT in our center. We retrieved data and identified the risk factors for 90-day posttransplant mortality. The perioperative clinical and laboratory parameters of patients who did or did not survive for 90 days were subjected to logistic regression analysis. Twelve patients died within 90 days. Results of univariate analysis indicated that the differences in patient survival were determined by the amount of intraoperative platelets transfused, the presence of posttransplant septicemia, and systemic immune-inflammation index (SII) at the time of listing with MELD scores ≥30. Multivariate analysis revealed that an SII ≥870 (× 109/L) and posttransplant septicemia were independent risk factors for 90-day mortality. Twenty-two patients had SIIs ≥870, and 13 of these patients had posttransplant septicemia. Of the 13 patients, 90-day mortality occurred in 10 cases. However, in 35 patients with SIIs <870, 90-day mortality due to posttransplant septicemia was recorded only in 1 patient. In conclusion, a preoperative SII ≥870 in a patient with a high MELD score may be a significant risk factor for early posttransplant mortality. Because posttransplant septicemia in patients with high SIIs can lead to fatality, a more intensive effort to prevent infection is needed for patients undergoing DDLT carrying such risk factors to avoid futile liver transplantation.

Lactoferrin Potentiates Inducible Regulatory T Cell Differentiation through TGF-ß Receptor III Binding and Activation of Membrane-Bound TGF-ß.

Lactoferrin (LF) is known to possess anti-inflammatory activity, although its mechanisms of action are not well-understood. The present study asked whether LF affects the commitment of inducible regulatory T cells (Tregs). LF substantially promoted Foxp3 expression by mouse activated CD4+T cells, and this activity was further enhanced by TGF-ß1. Interestingly, blocking TGF-ß with anti-TGF-ß Ab completely abolished LF-induced Foxp3 expression. However, no significant amount of soluble TGF-ß was released by LF-stimulated T cells, suggesting that membrane TGF-ß (mTGF-ß) is associated. Subsequently, it was found that LF binds to TGF-ß receptor III, which induces reactive oxygen species production and diminishes the expression of mTGF-ß-bound latency-associated peptide, leading to the activation of mTGF-ß. It was followed by phosphorylation of Smad3 and enhanced Foxp3 expression. These results suggest that LF induces Foxp3+ Tregs through TGF-ß receptor III/reactive oxygen species-mediated mTGF-ß activation, triggering canonical Smad3-dependent signaling. Finally, we found that the suppressive activity of LF-induced Tregs is facilitated mainly by CD39/CD73-induced adenosine generation and that this suppressor activity alleviates inflammatory bowel disease.

Optimal relative workload for managing low-injury risk in lower extremities of female field hockey players: A retrospective observational study.

ABSTRACT: Our study aimed to investigate the relative workload that is related to the injury in lower extremities of female field hockey players and to identify the optimal ratio of acute to chronic workloads (ACWR) depending on the playing position to manage low risk of sports-related injuries.Data were collected using a global positioning systems unit on a full-time basis and during competition among 52 players who were enrolled in Korea National Team. The ACWR was calculated by dividing the most recent 1 week workload by the prior 4 weeks workload. Injury risk was calculated for each category from very low to very high based on a z-score.In striker and midfielder, the injury risk was the lowest in the moderate-low category of total distance covered, meters per minute (MpM), repeated high-intensity effort bouts, and acceleration bouts, and the moderate-high category of high-intensity running distance (HID). The injury risk of a defender was the lowest in the moderate-low category of HID and MpM.The ACWR in total distance covered, MpM, repeated high-intensity effort bouts, and acceleration bouts should stay within the moderate-low category in striker and midfielder positions and HID and MpM in defender positions in order to manage low-risk of non-contact and soft tissue injuries in female field hockey players.

Microbial Community Composition in Municipal Wastewater Treatment Bioreactors Follows a Distance Decay Pattern Primarily Controlled by Environmental Heterogeneity.

Understanding spatiotemporal patterns in microbial community composition is a central goal of microbial ecology. The objective of this study was to better understand the biogeography of activated sludge microbial communities, which are important for the protection of surface water quality. Monthly samples were collected from 20 facilities (25 bioreactors) within 442 km of each other for 1 year. Microbial community composition was characterized by sequencing of PCR-amplified 16S rRNA gene fragments. Statistically significant distance decay of community similarity was observed in these bioreactors independent of clustering method (operational taxonomic units [OTUs] at 97% similarity, genus-level phylotypes) and community dissimilarity metric (Sørensen, Bray-Curtis, and weighted Unifrac). Universal colonizers (i.e., detected in all samples) and ubiquitous genus-level phylotypes (i.e., detected in every facility at least once) also exhibited a significant distance decay relationship. Variation partitioning analysis of community composition showed that environmental characteristics (temperature, influent characteristics, etc.) explained more of the variance in community composition than geographic distance did, suggesting that environmental heterogeneity is more important than dispersal limitation as a mechanism for determining microbial community composition. Distance decay relationships also became stronger with increasing distance between facilities. Seasonal variation in community composition was also observed from selected bioreactors, but there was no clear seasonal pattern in the distance decay relationships. IMPORTANCE Understanding the spatiotemporal patterns of biodiversity is a central goal of ecology. The distance decay of community similarity is one of the spatial scaling patterns observed in many forms of life, including plants, animals, and microbial communities. Municipal wastewater treatment relies on microorganisms to prevent the release of excessive quantities of nutrients and other pollutants, but relatively few studies have explored distance decay relationships in wastewater treatment bioreactors. Our results demonstrate a strong distance decay pattern in wastewater treatment bioreactors, regardless of the sequence clustering method or the community dissimilarity metric. Our results suggest that microbial communities in wastewater treatment bioreactors are not randomly assembled but rather exhibit a statistically significant spatial pattern.

Quantifying and predicting antimicrobials and antimicrobial resistance genes in waterbodies through a holistic approach: a study in Minnesota, United States.

The environment plays a key role in the spread and persistence of antimicrobial resistance (AMR). Antimicrobials and antimicrobial resistance genes (ARG) are released into the environment from sources such as wastewater treatment plants, and animal farms. This study describes an approach guided by spatial mapping to quantify and predict antimicrobials and ARG in Minnesota's waterbodies in water and sediment at two spatial scales: macro, throughout the state, and micro, in specific waterbodies. At the macroscale, the highest concentrations across all antimicrobial classes were found near populated areas. Kernel interpolation provided an approximation of antimicrobial concentrations and ARG abundance at unsampled locations. However, there was high uncertainty in these predictions, due in part to low study power and large distances between sites. At the microscale, wastewater treatment plants had an effect on ARG abundance (sul1 and sul2 in water; blaSHV, intl1, mexB, and sul2 in sediment), but not on antimicrobial concentrations. Results from sediment reflected a long-term history, while water reflected a more transient record of antimicrobials and ARG. This study highlights the value of using spatial analyses, different spatial scales, and sampling matrices, to design an environmental monitoring approach to advance our understanding of AMR persistence and dissemination.

Strategy for Selective Middle Hepatic Vein Reconstruction in Living Donor Liver Transplantation Using Right Lobe Graft: A Retrospective Observational Study.

BACKGROUND: The aim of this study was to verify the safety and feasibility of our selection criteria for middle hepatic vein (MHV) reconstruction in living donor liver transplantation (LDLT) using right lobe grafts. METHODS: A total of 153 LDLTs were performed using right lobe grafts in a tertiary hospital from 2006 to 2016. Among them, 52 cases without MHV reconstruction were compared with 101 recipients who underwent LDLT using right lobe graft with MHV reconstruction. Both groups were compared regarding indications for reconstruction, short-term and long-term complications, operative details, and outcomes. RESULTS: The two groups differed only in cold ischemic time (108.19 ± 49.81 minutes vs 146.37 ± 58.74 minutes) preoperatively. Short-term posttransplant outcomes, long-term overall survival, and long-term disease-free survival showed no significant differences between the 2 groups. After propensity score matching for both groups with and without MHV reconstruction to eliminate selection bias, the 2 groups were comparable. CONCLUSIONS: We found that our selection criteria for performing MHV reconstruction in LDLT using right lobe graft were feasible and safe. A routine MHV reconstruction is not necessary if the right lobe graft graft-to-recipient weight ratio is ≥1.0, right hepatic vein draining territory volume is ≥0.8, and recipient Model for End-Stage Liver Disease score is <20.

Direct Evidence for Deterministic Assembly of Bacterial Communities in Full-Scale Municipal Wastewater Treatment Facilities.

In this study, we investigated whether bacterial community composition in full-scale wastewater treatment bioreactors can be better explained by niche- or neutral-based theory (deterministic or stochastic) and whether bioreactor design (continuous flow versus fill and draw) affected community assembly. Four wastewater treatment facilities (one with quadruplicated continuous-flow bioreactors, two with one continuous-flow bioreactor each, and one with triplicate fill-and-draw bioreactors) were investigated. Bioreactor community composition was characterized by sequencing of PCR-amplified 16S rRNA gene fragments. Replicate bioreactors at the same wastewater treatment facility had largely reproducible (i.e., deterministic) bacterial community composition, although bacterial community composition in continuous-flow bioreactors was significantly more reproducible (P < 0.001) than in fill-and-draw bioreactors (Bray-Curtis dissimilarity, µ = 0.48 ± 0.06 versus 0.58 ± 0.08). Next, we compared our results to previously used indirect methods for distinguishing between deterministic and stochastic community assembly mechanisms. Synchronicity was observed in the bacterial community composition among bioreactors within the same metropolitan region, consistent with deterministic community assembly. Similarly, a null model-based analysis also indicated that all wastewater bioreactor communities were controlled by deterministic factors and that continuous-flow bioreactors were significantly more deterministic (P < 0.001) than fill-and-draw bioreactors (nearest-taxon index, µ = 3.8 ± 0.6 versus 2.7 ± 0.8). Our results indicate that bacterial community composition in wastewater treatment bioreactors is better explained by deterministic community assembly theory; simultaneously, our results validate previously used but indirect methods to quantify whether microbial communities were assembled via deterministic or stochastic mechanisms. IMPORTANCE Understanding the mechanisms of bacterial community assembly is one of the grand challenges of microbial ecology. In environmental systems, this challenge is exacerbated because replicate experiments are typically impossible; that is, microbial ecologists cannot fabricate multiple field-scale experiments of identical, natural ecosystems. Our results directly demonstrate that deterministic mechanisms are more prominent than stochastic mechanisms in the assembly of wastewater treatment bioreactor communities. Our results also suggest that wastewater treatment bioreactor design is pertinent, such that the imposition of feast-famine conditions (i.e., fill-and-draw bioreactors) nudge bacterial community assembly more toward stochastic mechanisms than the imposition of stringent nutrient limitation (i.e., continuous-flow bioreactors). Our research also validates the previously used indirect methods (synchronous community dynamics and an application of a null model) for characterizing the relative importance of deterministic versus stochastic mechanisms of community assembly.