Bio-Based Waterborne Poly(Vanillin-Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free,facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin(MV)using vanillin.The resulting MV not only imparted antibacterial properties to coatings layered on leather,but could also be employed as a green alternative to petroleum-based carcinogen styrene(St).Herein,MV was copolymerized with butyl acrylate(BA)to obtain waterborne bio-based P(MV-BA)miniemulsion via miniemulsion polymerization.Subsequently,MXene nanosheets with excellent photothermal conversion performance and antibacterial properties,were introduced into the P(MV-BA)miniemulsion by ultrasonic dispersion.During the gradual solidification of P(MV-BA)/MXene nanocomposite miniemulsion on the leather surface,MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene,which prompted its full exposure to light and bacteria,exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy.In particular,when the dosage of MXene nanosheets was 1.4 wt%,the surface temperature of P(MV-BA)/MXene nanocomposite miniemulsioncoated leather(PML)increased by about 15℃ in an outdoor environment during winter,and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100%under the simulated sunlight treatment for 30 min.Moreover,the introduction of MXene nanosheets increased the air permeability,water vapor permeability,and thermal stability of these coatings.This study provides a new insight into the preparation of novel,green,and waterborne bio-based nanocomposite coatings for leather,with desired warmth retention and antibacterial properties.It can not only realize zerocarbon heating based on sunlight in winter,reducing the use of fossil fuels and greenhouse gas emissions,but also improve ability to fight off invasion by harmful bacteria,viruses,and other microorganisms.

Establishment of predictive models and determinants of preoperative gastric retention in endoscopic retrograde cholangiopancreatography

BACKGROUND Study on influencing factors of gastric retention before endoscopic retrograde cholangiopancreatography(ERCP)background:With the wide application of ERCP,the risk of preoperative gastric retention affects the smooth progress of the operation.The study found that female,biliary and pancreatic malignant tumor,digestive tract obstruction and other factors are closely related to gastric retention,so the establishment of predictive model is very important to reduce the risk of operation.METHODS A retrospective analysis was conducted on 190 patients admitted to our hospital for ERCP preparation between January 2020 and February 2024.Patient baseline clinical data were collected using an electronic medical record system.Patients were randomly matched in a 1:4 ratio with data from 190 patients during the same period to establish a validation group(n=38)and a modeling group(n=152).Patients in the modeling group were divided into the gastric retention group(n=52)and non-gastric retention group(n=100)based on whether gastric retention occurred preoperatively.General data of patients in the validation group and identify factors influencing preoperative gastric retention in ERCP patients.A predictive model for preoperative gastric retention in ERCP patients was constructed,and calibration curves were used for validation.The receiver operating characteristic(ROC)curve was analyzed to evaluate the predictive value of the model.RESULTS We found no statistically significant difference in general data between the validation group and modeling group(P>0.05).The comparison of age,body mass index,hypertension,and diabetes between the two groups showed no statistically significant difference(P>0.05).However,we noted statistically significant differences in gender,primary disease,jaundice,opioid use,and gastrointestinal obstruction between the two groups(P<0.05).Mul-tivariate logistic regression analysis showed that gender,primary disease,jaundice,opioid use,and gastrointestinal obstruction were independent factors influencing preoperative gastric retention in ERCP patients(P<0.05).The results of logistic regression analysis revealed that gender,primary disease,jaundice,opioid use,and gastroin-testinal obstruction were included in the predictive model for preoperative gastric retention in ERCP patients.The calibration curves in the training set and validation set showed a slope close to 1,indicating good consistency between the predicted risk and actual risk.The ROC analysis results showed that the area under the curve(AUC)of the predictive model for preoperative gastric retention in ERCP patients in the training set was 0.901 with a standard error of 0.023(95%CI:0.8264-0.9567),and the optimal cutoff value was 0.71,with a sensitivity of 87.5 and specificity of 84.2.In the validation set,the AUC of the predictive model was 0.842 with a standard error of 0.013(95%CI:0.8061-0.9216),and the optimal cutoff value was 0.56,with a sensitivity of 56.2 and specificity of 100.0.CONCLUSION Gender,primary disease,jaundice,opioid use,and gastrointestinal obstruction are factors influencing preoperative gastric retention in ERCP patients.A predictive model established based on these factors has high predictive value.

Distribution of soil aggregates and organic carbon in deep soil under long-term conservation tillage with residual retention in dryland

To ascertain the effects of long-term conservation tillage and residue retention on soil organic carbon(SOC) content and aggregate distribution in a deep soil(>20-cm depth) in a dryland environment,this paper analyzed the SOC and aggregate distribution in soil, and the aggregate-associated organic carbon(OC) and SOC physical fractions. Conservation tillage(reduced tillage with residue incorporated(RT) and no-tillage with residue mulch(NT)) significantly increased SOC sequestration and soil aggregation in deep soil compared with conventional tillage with residue removal(CT). Compared with CT, RT significantly increased the proportion of small macroaggregates by 23%–81% in the 10–80 cm layer, and the OC content in small macroaggregates by 1%–58% in the 0–80 cm layer. RT significantly increased(by 24%–90%) the OC content in mineral-SOC within small macroaggregates in the 0–60 cm layer, while there was a 23%–80% increase in the 0–40 cm layer with NT. These results indicated that:(1) conservation tillage treatments are beneficial for soil aggregation and SOC sequestration in a deep soil in a dryland environment; and(2)the SOC in mineral-associated OC plays important roles in soil aggregation and SOC sequestration. In conclusion, RT with NT is recommended as an agricultural management tool in dryland soils because of its role in improving soil aggregation and SOC sequestration.

Assessment of Retention Ponds and Its Impacts on Health of Residents in Mogadishu, Somalia: Mixed Methods

The purpose of this study was to evaluate the effects of retention ponds on the environment and population health by analyzing water samples from various ponds in Mogadishu, to determine the prevalence of waterborne illnesses that occur during the rainy season in Mogadishu, and to find out what experts thought about the effects of retention ponds on the environment as well as population health in Mogadishu. Methods: Mixed designs were used in the study. The first design is an exploratory study where samples are taken from different retention ponds in Mogadishu. The second design involves gathering secondary data from the online FSNAU Dashboard regarding the incidence of rainfall and waterborne illnesses including malaria and cholera. Additionally, a cross-sectional survey of expert opinions using questionnaires was the third design. The 10 water samples were taken from retention ponds in Mogadishu as part of the sample size. Data on the fourth month was also gathered using the FNSAU dashboard, and seventy sample sizes were used for the expert self-administered questionnaire for the third design. Excel was used for data analysis in the initial design. While BMI SPSS versions 22 were used to analyze the data from the Self-administered Questionnaire, additional methods were utilized to compute descriptive statistics, such as mean and standard deviation, and to analyze demographic data in a frequency table. Findings: The results show that three samples had unsatisfactory scores (Grade D): Yaqshid (Warshadda Bastada) had a WQI of 80.85, Boondheer (Bondher Pond) had a WQI of 80.64, and Wartanabad (Xamar Jadiid Pond) had a WQI of 80.89. The remaining samples were all rated as fair (grade), which indicates that they ranged from 50 to 75. The months with the largest rainfall already occurred in December, November, and October, when the prevalence of diseases during the rainy season was highest for cholera cases. Although October and December saw a significant number of malaria cases, November did not. Retention ponds’ overall effects on residential environments were evaluated, and the results showed that the standard deviation was 0.802 and the cumulative average mean scores were 4.41 overall. This indicates that the respondents were in agreement that retention ponds in Mogadishu, Somalia, had an effect on residential areas. Recommendation: The study suggested that in order to identify retention pond contamination and create treatment units for its management, the Ministry of Health forms a district-level public health committee. All districts must have a sewer system installed by the local government, and retention ponds must be made easier in order to move waste outside of the city.

Fire and retention island remnants have similar deadwood carbon stock a decade after disturbances in boreal forests of Alberta

In an attempt to reconcile wood extraction and forest biodiversity in managed boreal forests,ecosystem-based forest management(EBM)has become the de facto management approach.Retention forestry represents one prominent way that EBM is implemented in many parts of the world.Retention patches commonly left after harvesting serve as analogues of fire island remnants,which are patches of unburned forests in the burned forest matrix.Although the persistence of retention patches has been questioned,few studies have attempted to quantitatively compare forest attributes in both burned and harvested forests.As part of a larger program examining multiple aspects of ecosystem function in fire and harvest island remnants,we investigated the impact of disturbance type(fire/harvest)and forest edges on C stock in snags and coarse woody debris(CWD)found in island remnants in mixedwood boreal forests of Alberta,Canada.Total C stock(in snags and CWD)was similar between the two disturbance types and edge plots had similar total deadwood C stocks to interiors.The edges of island remnants had about two-fold more snag C stock than their interiors in both disturbance types,but C stock in CWD was unaffected by edge effects and disturbance type.Our results suggest that deadwood C dynamics in island remnants in fire and harvest disturbed boreal forests were similar,thus lending support for the continued implementation of retention forestry in Alberta.

Factors Promoting Retention of Nurses in Three Private Hospitals of Lahore: A Cross Sectional Descriptive Survey

Introduction: Pakistan has a large number of professional nurses but a higher rate of turnover contributes towards the shortage of nurses which is intensified by nurses’ immigration, lack of recruitment of new nurses and retirement of senior nurses. Aim: The study aimed at examining the factors that increase retention of nurses. Research Method: The study is descriptive cross sectional with a sample of 150 nurses including both the genders, from 3 private hospitals located in Pakistan. A convenient sampling technique was used. The data collection was done through close ended questionnaires based on 20 questions. Data collection was done quantitatively and then data was entered in SPSS. Correlation and regression tests were performed. Findings: The analysis revealed that 91.3% nurses are loyal to their hospitals but, 8.7%nurses can switch the hospital for different reasons. It was also found that the idea of leaving the job based on the intention of moving to abroad and public sector was higher than the retirement and other causes. Resultantly, enhancements in nurses’ work environments have the ability to decrease nurses’ job burnout and turnover and increase patients’ satisfaction. Recommendations: Hospital leaders should implement effective strategies to encourage nurses to continue their job by motivation, strengthening management skills within the hospital and improving a positive work environment by promoting teamwork, continuous learning, trust, respect and flexible arrangements which can lead towards achieving better results.However, further studies quantitatively and qualitatively can explore more factors related to dissatisfaction of nurses. Health systems policy makers should lead by developing related strategies for the retention of nurses.

Water retention behavior and shear strength of artificially cemented granite residual soil subjected to free drying

Artificially cemented soils have been widely used as filling materials in highway and railway construction.The shear strength evolution of filling materials upon moist variation can determine the stability of subgrade and embankments.This study conducted water retention tests,MIP tests,and multi-stage triaxial shear tests on cement-treated granite residual soil(GRS)to determine its water retention curve(WRC)upon free drying,pore structure,and peak shear strength qf,respectively.The water retention behavior and shear strength evolution upon free drying were modeled based on the dual-porosity structure of cement-treated GRS and the effective stress principle,respectively.Results show that the drying-WRC is bimodal and higher cement dosage yields a more severe decrease in the water retention capacity within a specific suction range.For a given confining pressure,the peak shear strength qf increased with increasing cement dosage or suction value s.The peak shear strength qf also solely depends on the suction value in the peak stress state.In addition,the cement-treated GRS has a bimodal pore size distribution curve,and its macro-and micro-void ratios remain almost unchanged after free drying.The bimodal drying-WRC of the cement-treated GRS can be modeled by differentiating the water retention mechanisms in macro-and micro-pores.Moreover,using the macro-pore degree of saturation as the effective stress parameterχ=S_(rM),the q_(f)–p′_(f)relationship(where p′_(f)is the effective mean pressure at failure)under various suction and stress conditions can be unified,and the q_(f)–s relationships at various net confining pressuresσ_(3),net can be well reproduced.These findings can help design subgrade and embankments constructed by artificially cemented GRS and assess their safe operation upon climate change.

A systematic review of the efficacy of traditional Chinese medicine retention enema in the treatment of ulcerative colitis

The objective of this study is to summarize the efficacy and safety of traditional Chinese medicine(TCM)enema in the treatment of ulcerative colitis(UC).The randomized controlled trials on TCM enema intervention in the treatment of UC were searched in seven databases:PubMed,Embase,Web of Science,CBM,CNKI,Wanfang Database,and VIP Database from January 1,2013 to June 6,2022,and the data were analyzed using RevMan 5.3 software.A total of 18 studies involving 1514 UC patients were included.Meta analysis results showed that compared with conventional Western medicine,Chinese medicine enema had a significant effect on UC,and the clinical effective rate of the experimental group using Chinese medicine enema was 4.45 times that of the control group using conventional Western medicine(odds ratio=4.45,95%confidence interval[3.27,6.06]).Therefore,Chinese medicine enema is effective in the treatment of UC,and can significantly reduce related symptoms.

High Urine Retention: Experience in a Series of Patients with Renal Failure Patients

Purpose: High urinary retention (HUR) can negatively impact renal function. Our study aimed to present the epidemiological, diagnostic, and therapeutic aspects of HUR in a Senegalese academic hospital. Patients and Methods: We conducted a retrospective study of 70 patients with HUR associated with renal failure from January 2017 to December 2020. Parameters examined included: age, sex, coexisting conditions affecting renal function, clinical symptoms, diagnostic tests, causes of HUR, urinary diversion, and patient outcomes. Results: The average age was 66, with a majority of male patients (87%). Twenty-three patients had pre-existing medical conditions. Oligo-anuria was the most common reason for detecting HUR (70%). Half of the patients had an ECOG score ≥ 2. The mean creatinine level was 50.7 mg/l. Nineteen patients exhibited hydroelectrolytic disorders. Bacterial colonization was observed in 25 patients. Ultrasound and computed tomography were the most frequently performed imaging tests (100% and 62.8%, respectively). Sixty-seven patients had ureterohydronephrosis (UHN), with bilateral UHN in 88.6% of cases. Pelvic cancers (47.1%) were the primary cause of HUR, primarily bladder cancers (27.1%). Nephrostomy was the most common urinary drainage method (50%), particularly for obstructions due to pelvic cancer (88.6%). The majority of patients (52.8%) regained normal renal function after drainage. Nineteen deaths occurred among elderly patients with compromised general health. Conclusion: Urinary drainage significantly improved renal function for most patients. Pelvic cancer emerged as the leading cause of HUR. Nephrostomy was the predominant drainage method.

Removal of biofilm is essential for long-term ventilation tuberetention

BACKGROUND Although long-term retention of a ventilation tube is required in many ear diseases,spontaneous removal of conventional ventilation tube is observed in patients within 3 to 12 mo.To address this issue,we aimed to determine a new method for long-term retention of the ventilation tube.AIM To explore the value of removing the biofilm for long-term retention of tympanostomy ventilation tubes.METHODS A case-control study design was used to evaluate the safety and effectiveness of long-term tube retention by directly removing the biofilm(via surgical exfoliation)in patients who underwent myringotomy with ventilation tube placement.The patients were randomly divided into two groups:Control group and treatment group.Patients in the treatment group underwent regular biofilm exfoliation surgery in the clinic,whereas those in the control group did not have their biofilm removed.Only conventional ventilation tubes were placed in this study.Outcome measures were tube position and patency.Tube retention time and any complications were documented.RESULTS Eight patients with biofilm removal and eight patients without biofilm removal as a control group were enrolled in the study.The tympanostomy tube retention time was significantly longer in the treatment group(43.5±26.4 mo)than in the control group(9.5±6.9 mo)(P=0.003).More tympanostomy tubes were found to be patent and in correct position in the treatment group during the follow-up intervals than in the control group(P=0.01).CONCLUSION Despite the use of short-term ventilation tubes,direct biofilm removal can be a well-tolerated and effective treatment for long-term tube retention of tympanostomy ventilation tubes in patients who underwent myringotomy.

Study on the Application Effect of Flexible Nursing Care in Patients with Postpartum Urinary Retention and its Effect on Lactation

Objective: To study the application effect of flexible nursing in patients with postpartum urinary retention and its effect on lactation. Methods: A total of 200 cases of postpartum urinary retention patients admitted between January 2021 and January 2022 were selected and randomly grouped into two groups, a control group (conventional nursing) and an observation group (flexible nursing), of 100 cases each. The time of onset of lactation, the lactation volume score, urinary indicators, the amount of post-partum hemorrhage, and the quality of life score of the two groups were compared. Results: The observation group’s lactation initiation time (21.41 ± 1.52) h and lactation volume score (2.11 ± 0.52) were better than that of the control group (P < 0.05). The observation group’s first urination time (2.11 ± 0.51) min was lower than the control group, while the urinary retention completely relieved time (33.12 ± 8.61) h, and first urinary volume (262.17 ± 52.41) mL was higher than that of the control group (P < 0.05). The amount of postpartum hemorrhage in the observation group (151.21 ± 22.12) mL was less than that in the control group (P < 0.05). The scores of somatic functioning (86.25 ± 2.20), psychological functioning (91.56 ± 1.45), social functioning (89.25 ± 2.45), and material life (89.75 ± 1.45) of the observation group were higher than those of the control group after nursing (P < 0.05). Conclusion: Flexible nursing care in patients with postpartum urinary retention exhibited significant nursing effects and lactation function was effectively improved.

Imperative for long-term management and surveillance in Kawasaki disease

Kawasaki disease(KD)is a significant pediatric vasculitis known for its potential to cause severe coronary artery complications.Despite the effectiveness of initial treatments,such as intravenous immunoglobulin,KD patients can experience long-term cardiovascular issues,as evidenced by a recent case report of an adult who suffered a ST-segment elevation myocardial infarction due to previous KD in the World Journal of Clinical Cases.This editorial emphasizes the critical need for long-term management and regular surveillance to prevent such complications.By drawing on recent research and case studies,we advocate for a structured approach to follow-up care that includes routine cardiac evaluations and preventive measures.

Long-Term Effects of Alternative Residue Management Practices on Soil Water Retention in a Wheat-Soybean, Double-Crop System in Eastern Arkansas

Soil water retention is a critical aspect of agricultural management, especially in areas such as the Lower Mississippi River Alluvial Valley that face potential water shortages in the near future. Previous studies have linked changes in soil water retention characteristics to agricultural management practices, especially as they affect the accumulation of soil organic matter (SOM). Therefore, the objective of this study was to determine the relationship between soil water potential and gravimetric soil water content in the top 7.5 cm as affected by nitrogen (N) fertilization/residue level (high and low), residue burning (burning and non-burning), tillage (conventional and no-tillage), and irrigation (irrigated and non-irrigated) after 12 complete cropping cycles in a wheat (Triticum aestivum L.)-soybean [Glycine max (L.) Merr.], double-crop production system in the Delta region of eastern Arkansas using soil wetting curves. The soil investigated was a Calloway silt loam (fine silty, mixed, active, thermic Glossaquic Fraglossudalf). The slope characterizing the relationship between the natural logarithm of the soil water potential and the gravimetric soil water content was only affected (P < 0.05) by the N-fertilization/residue-level treatment, while the intercept was unaffected by any field treatment. Averaged across tillage, burning, and irrigation, soil water contents under the high-exceeded those under low-N-fertilization/residue-level treatment at the same water potential, with the greatest differences observed at water contents > 0.12 g·g-1. Understanding the ways in which alternative residue management practices affect soil water retention characteristics is an important component of conserving irrigation water resources.

Involvement Load Hypothesis and Senior Middle School Students' Vocabulary Retention

The purpose of the paper is to study retention of vocabulary acquired incidentally on task-induced involvement by senior middle school students. Grade two of senior middle students participated in the experiments, testing whether retention of vocabulary acquired incidentally is contingent on amount of task-induced involvement.Using short-and long term, namely immediate posttest and delayed posttest, retention of twelve unfamiliar words was investigated in three learning tasks (reading, reading plus fill-in and writing) with varying degrees of “involvement load”- various combinations of need, search and evaluation. The results of the experiment partially support the Involvement Load Hypothesis: retention in the writing group was higher than that in the reading plus fill-in group; retention in the reading plus fill-in group was higher than that in the reading group. The results are discussed in light of the construct of task-induced involvement.

Soil Carbon Pool Management Index under Different Straw Retention Regimes

[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon （CToc）, active carbon （CA） and mineralized carbon （CM） were analyzed, and carbon pool active （A）, carbon pool active index （A/）, carbon pool index （CPI） and carbon pool management index （CPMi） for each treat- ment were calculated. [Result] Compared with the unfertilized treatment （CK）, CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.

INDIGESTION OF FOOD RETENTION IN CHILDREN TREATED BY ACUPUNCTURE AND MASSAGE

Objective By acupuncture plus massage to treat poor appetite induced by indigestion of food retention in children to restore their normal appetite. Methods 476 cases of indigestion of food retention in children were treated by acupuncture plus massage. Results 385 of the 476 cases were cured, and 91 cases were improved by one treatment with a total effective rate of 100%. Conclusion Acupuncture plus massage provided remarkable therapeutic effects on indigestion of food retention in children.

Effects of Different Decolorants on Retention Rate of Total Triterpenes in Fruit and Rattan Stems of Schisandra chinensis(Turcz.) Baill

This study was to investigate the decoloration effects of activated clay, activated carbon, diatomite, Ca group bentonite, kaolin, activated aluminum oxide, magnesium oxide and attapulgite. Ultraviolet-visible spectroscopywas adopted to de- tect the absorbanees of the extracts of Schisandra chinensis fruit and rattan stems, the contents of total triterpenoids in S. chinensis fruit and rattan stems were deter- mined, and the decoloration rate and the retention rate of total triterpenoids of S. chi- nensis fruit and rattan stems were calculated. The results indicated that, attapulgite exhibited the best decoloration effect on the extract of S. chinensis fruit, with a de- coloration rate up to 60.47%, activated carbon exhibited a better decoloration effect on the extract of S. chinensis rattan stems, with a decoloration rate up to 69.24%, and they had relatively higher retention rates of total triterpenoids. In the eight de- colorants, attapulgite showed the best decoloration effect on the extract of S. chi- nensis fruit, and activated carbon exhibited the best decoloration effect on the ex- tract of S. chinensisrattan stems.

Spatial-temporal Patterns and Driving Forces of Water Retention Service in China

Overwhelming water-deficiency conditions and an unbalanced water supply and demand have been major concerns of both the Chinese government and the general public during recent decades. Studying the spatial-temporal patterns and impact factors that influence water retention in China is important to enhance the management of water resources in China and other similar countries. We employed a revised Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model and regression analyses to investigate the water retention service in China. The results showed that the southeastern China generally performed much better than Northwest China in terms of the spatial distribution of water retention. In general, the efficacy of the water retention service in China increased from 2000 to 2014; although some areas still had a downward trend. Water retention service increased significantly(P < 0.05) in aggregate in the Qinghai-Tibet Plateau, and the Da Hinggan Mountains and Xiao Hinggan Mountains. However, the service in southwestern China showed a decreasing trend(P < 0.05), which would have significant negative impact on the downstream population. This study also showed that in China the changes in water retention service were primarily due to climate change(which could explain 83.49% of the total variance), with anthropogenic impact as a secondary influence(likewise the ecological programs and socioeconomic development could explain 9.47% and 1.06%, respectively). Moreover, the identification of water retention importance indicated that important areas conservation and selection based on downstream beneficiaries is vital for optimization protection of ecosystem services, and has practical significance for natural resources and ecosystem management.

Treatment of acute periprosthetic infections with prosthesis retention: Review of current concepts

Periprosthetic joint infection(PJI) is a devastating complication after total joint arthroplasty, occurring in approximately 1%-2% of all cases. With growing populations and increasing age, PJI will have a growing effect on health care costs. Many risk factors have been identified that increase the risk of developing PJI, including obesity, immune system deficiencies, malignancy, previous surgery of the same joint and longer operating time. Acute PJI occurs either postoperatively(4 wk to 3 mo after initial arthroplasty, depending on the classification system), or via hematogenous spreading after a period in which the prosthesis had functioned properly. Diagnosis and the choice of treatment are the cornerstones to success. Although different definitions for PJI have been used in the past, most are more or less similar and include the presence of a sinus tract, blood infection values, synovial white blood cell count, signs of infection on histopathological analysis and one ormore positive culture results. Debridement, antibiotics and implant retention(DAIR) is the primary treatment for acute PJI, and should be performed as soon as possible after the development of symptoms. Success rates differ, but most studies report success rates of around 60%-80%. Whether single or multiple debridement procedures are more successful remains unclear. The use of local antibiotics in addition to the administration of systemic antibiotic agents is also subject to debate, and its pro's and con's should be carefully considered. Systemic treatment, based on culture results, is of importance for all PJI treatments. Additionally, rifampin should be given in Staphylococcal PJIs, unless all foreign material is removed. The most important factors contributing to treatment failure are longer duration of symptoms, a longer time after initial arthroplasty, the need for more debridement procedures, the retention of exchangeable components, and PJI caused by Staphylococcus(aureus or coagulase negative). If DAIR treatment is unsuccessful, the following treatment option should be based on the patient health status and his or her expectations. For the best functional outcome, one- or two-stage revision should be performed after DAIR failure. In conclusion, DAIR is the obvious choice for treatment of acute PJI, with good success rates in selected patients.

Effect of sludge retention time on sludge characteristics and membrane fouling of membrane bioreactor

Three identical membrane bioreactors （MBRs） were operated over 2 years at different sludge retention time （SRT） of 10 d, 40 d and no sludge withdrawal （NS）, to elucidate and quantify the effect of SRT on the sludge characteristics and membrane fouling. The hydraulic retention times of these MBRs were controlled at 12 h. With increasing SRT, the sludge concentrations in the MBRs increased, whereas the ratio of volatile suspended solid to the total solid decreased, and the size of sludge granule diminished in the meantime. A higher sludge concentration at long SRT could maintain a better organic removal efficiency, and a longer SRT was propitious to the growth of nitrifiers. The performance of these MBRs for the removal of COD and NH4^＋-N did not change much with different SRTs. However, the bioactivity decreased as SRT increase. The measurement of specific oxygen uptake rates （SOUR） and fluorescence in situ hybridization （FISH） with rRNA-targeted oligonucleotide probes testified that SOUR and the proportion of the bacteria-specific probe EUB338 in all DAPI-stainable bacteria decreased with increasing SRT. The concentrations of total organic carbon, protein, polysaccharides and soluble extracellular polymeric substance （EPS） in the mixed liquor supernatant also decreased with increasing SRT. The membrane fouling rate was higher at shorter SRT, and the highest fouling rate appeared at a SRT of 10 d. Both the sludge cake layer and gel layer had contribution to the fouling resistance, but the relative contribution of the gel layer decreased as SRT increase.