Recent advances in quantifying the inactive lithium and failure mechanism of Li anodes in rechargeable lithium metal batteries

Lithium metal is considered as the ultimate anode material for the next generation of high-energy density batteries.However,non-uniform lithium dendrite growth,serious electrolyte consumption,and significant volume changes during lithium deposition/stripping processes lead to sustained accumulation of inactive lithium and poor cycling reversibility.Quantifying the formation and evolution of inactive lithium under different conditions and fully evaluating the complex failure modes are the key issues in this challenging field.This article comprehensively reviews recent research progress on the quantification of formation and evolution of inactive lithium detected by different quantitative techniques in rechargeable lithium metal batteries.The key research challenges such as failure mechanism,modification strategies and operando characterization of lithium metal anodes are systematically summarized and prospected.This review provides a new angle of view to understand failure mechanism of lithium metal anodes and inspiration and guidance for the future development of rechargeable lithium metal batteries.

Serum Immunoglobulin Concentrations in Juvenile Idiopathic Arthritis Cases during Active and Inactive Disease States

Background: Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in children. Both the humoral and cell mediated immunities are involved in the pathogenesis of JIA. It is reported that overall immunoglobulin levels in JIA patients are significantly higher than their control during the active state of disease. Methodology: This prospective observational study was conducted over a period of 18 months All the newly diagnosed oligo-articular and poly-articular JIA patients having active disease were included by purposive sampling. Data were collected by a semi-structured predesigned questionnaire. Result: Most of the study subjects (57.6%) belonged to age group > 3 - 9 years. Oligo JIA was diagnosed in 66.7% and poly JIA in 33.3% of JIA children. The difference in mean (±SD) ESR (33.52 ± 21.29 and 15.09 ± 7.71 mm in 1st hour) at active and inactive states was highly significant. Mean (±SD) difference of IgG, IgM and IgA in active and inactive states of disease were highly significant. Conclusion: Higher and abnormal levels of immunoglobulin (IgG, IgM, and IgA) were present among JIA patients in active disease state which became normal during inactive disease state after treatment.

MEC辅助的Inactive状态用户动态位置管理方案

移动边缘计算(mobile edge computing,MEC)作为5G网络架构演进的关键技术,能够满足系统对于吞吐量、时延及智能化要求。同时,5G引入用户(user equipment,UE)无线资源控制(radio resource control,RRC) Inactive状态作为用户的主要状态。在分析MEC的特点、网络架构、装置结构的基础上,基于Inactive状态特点,对当前Inactive状态的寻呼和位置跟踪方案进行分析和对比,提出一种基于MEC的UE数据包缓存和动态位置管理方案,该方案由部署在靠近无线接入网(radio access network,RAN)基站侧的MEC缓存Inactive UE数据包,并更新UE的RAN通知区域(RAN notification area,RNA)。和传统的方案相比,该方案能有效解决锚点g NB(5G-NodeB)的容量问题,并且实现UE有效的位置管理。

Molecular characteristics and stages of chronic hepatitis B virus infection

Hepatitis B virus (HBV) is a common viral pathogen that causes a substantial health burden worldwide. Remarkable progress has been made in our understanding of the natural stages of chronic HBV infection. A dynamic balance between viral replication and host immune response is pivotal to the pathogenesis of liver disease. Knowledge of the HBV genome organization and replication cycle can unravel HBV genotypes and molecular variants, which contribute to the heterogeneity in outcome of chronic HBV infection. Most HBV infections are spontaneously resolved in immunocompetent adults, whereas they become chronic in most neonates and infants at a great risk of developing complications such as cirrhosis and hepatocellular carcinoma (HCC). Those with chronic HBV infection may present in one of the four phases of infection: immune tolerance, immune clearance [hepatitis B eantigen (HBeAg)-positive chronic hepatitis B (CHB)], inactive carrier state, and reactivation (HBeAg-negative CHB). Understanding the dynamic nature of chronic HBV infection is crucial in the management of HBV carriers. Long-term monitoring and optimal timing of antiviral therapy for chronic HBV infection help to prevent progression of HBV-related liver disease to its later stage, particularly in patients with higher risk markers of HCC, such as serum DNA concentration, HBeAg status, serum aminotransferase, HBV genotypes, and pre-core or core mutants.

Overweight, obesity, and screen-time viewing among Chinese school-aged children: National prevalence estimates from the 2016 Physical Activity and Fitness in China—The Youth Study

Purpose: This study presents the most recent estimates of prevalence of overweight, obesity, and screen-time viewing among Chinese school-aged children. Demographic differences in these estimates between sexes and resident locales were also examined.Methods: Cross-sectional analyses of 116,615 Chinese school children 9 to 17 years of age who participated in the 2016 Physical Activity and Fitness in China—The Youth Study project. Outcomes were the prevalence of children's overweight(85 th ≤ body mass index(BMI) < 95 th percentile) and obesity(BMI ≥95 th percentile)(defined by the Working Group on Obesity in China) and not meeting screen-time viewing recommendations("not meeting" was defined as more than 2 h per day of viewing activities after school). Analyses were conducted on the whole sample and by school grade cohorts(primary, junior middle, and junior high schools), sex, and residence locales(urban, rural).Results: Overall, 14.4%(95% confidence interval(CI): 13.8%–15.0%) of children and adolescents were overweight, 11.9%(95%CI: 11.0%–13.0%) were obese, and 36.8%(95%CI: 34.7%–38.9%) did not meet screen-time viewing recommendations. Across the 3-grade cohorts, boys were more likely to be obese than girls, and primary and junior middle school children living in urban areas were more likely to be obese than those living in rural areas. Primary and junior middle school boys were less likely to meet screen-time recommendations than girls, and junior high school children living in urban areas were less likely to meet screen-time recommendations than school children of the same grades living in rural areas.Conclusion: In 2016, the prevalence of obesity among Chinese school children was about 12%, and about 37% of them did not meet screen-time viewing recommendations. The prevalence of obesity and sedentary behavior was generally higher among boys than among girls, and it was higher for children living in urban areas than for those living in rural areas.

Hepatitis B surface antigen clearance in inactive hepatitis B surface antigen carriers treated with peginterferon alfa-2a

AIM: To examine the association between interferon(IFN) therapy and loss of hepatitis B surface antigen(HBs Ag) in inactive HBs Ag carriers. METHODS: This was a retrospective cohort study in inactive HBs Ag carriers, who were treatment-naive, with a serum HBs Ag level < 100 IU/m L and an undetectable hepatitis B virus(HBV) DNA level(< 100 IU/m L). All the 20 treated patients received subcutaneous PEG-IFN alfa-2a 180 μg/wk for 72 wk and were then followed for 24 wk. There were 40 untreated controls matched with 96 wk of observation. Serum HBs Ag, HBV DNA, and alanine aminotransferases were monitored every 3 mo in the treatment group and every 3-6 mo in the control group. RESULTS: Thirteen(65.0%) of 20 treated patients achieved HBs Ag loss, 12 of whom achieved HBs Ag seroconversion. Mean HBs Ag level in treated patients decreased to 6.69 ± 13.04 IU/m L after 24 wk of treatment from a baseline level of 26.22 ± 33.00 IU/m L. Serum HBV DNA level remained undetectable(< 100 IU/m L) in all treated patients during the study. HBs Ag level of the control group decreased from 25.72 ± 25.58 IU/m L at baseline to 17.11 ± 21.62 IU/m L at week 96(P = 0.108). In the control group, no patient experienced HBs Ag loss/seroconversion, and two(5.0%) developed HBV reactivation.CONCLUSION: IFN treatment results in HBs Ag loss and seroconversion in a considerable proportion of inactive HBs Ag carriers with low HBs Ag concentrations.

Metabolic rates and biochemical compositions of Apostichopus japonicus (Selenka) tissue during periods of inactivity

Estivation, hibernation, and starvation are indispensable inactive states of sea cucumbers Apostichopusjaponicus in nature and in culture ponds. Generally, temperature is the principal factor that induces estivation or hibernation in the sea cucumber. The present study provided insight into the physiological adaptations ofA. japonicus during the three types of inactivity （hibernation, estivation, and starvation） by measuring the oxygen consumption rates （Vo2） and biochemical compositions under laboratory conditions of low （3℃）, normal （17℃） and high （24℃） temperature. The results show that the characteristics of A. japonicus in dormancy （hibernation and estivation） states were quite different from higher animals, such as fishes, amphibians, reptiles, and mammals, but more closely resembled a semi-dormant state. It was observed that the shift in the A. japonicus physiological state from normal to dormancy was a chronic rather than acute process, indicated by the gradual depression of metabolic rate. While metabolic rates declined 44.9% for the estivation group and 71.7% for the hibernation group, relative to initial rates, during the 36 d culture period, metabolic rates were not maintained at constant levels during these states. The metabolic depression processes for sea cucumbers in hibernation and estivation appeared to be a passive and an active metabolic suppression, respectively. In contrast, the metabolic rates （128.904-11.70 μg/g h） of estivating sea cucumbers were notably higher （107.85±6.31 μg/gh） than in starving sea cucumbers at 17℃, which indicated that the dormancy mechanism here, as a physiological inhibition, was not as efficient as in higher animals. Finally, the principle metabolic substrate or energy source of sea cucumbers in hibernation was lipid, whereas in estivation they mainly consumed protein in the early times and both protein and lipid thereafter.

Hepatitis B in patients with hematological diseases: An update

Hepatitis B virus(HBV) reactivation(HBVr) in patients undergoing immunosuppressive therapy is still a hot topic worldwide. Its prevention and management still represents a challenge for specialists dealing with immunosuppressed patients. Aim of this paper is to provide a critical review of the relevant information emerged in the recent literature regarding HBV reactivation following immunosuppressive treatments for oncohematological tumors. A computerized literature search in MEDLINE was performed using appropriate terms arrangement, including English-written literature only or additional relevant articles. Articles published only in abstract form and case reports not giving considerable news were excluded. Clinical manifestation of HBVr can be manifold, ranging from asymptomatic self-limiting anicteric hepatitis to life-threatening fulminant liver failure. In clusters of patients adverse outcomes are potentially predictable. Clinicians should be aware of the inherent risk of HBVr among the different virological categories(active carriers, occult HBV carriers and inactive carriers, the most intriguing category), and classes of immunosuppressive drugs. We recommend that patients undergoing immunosuppressive treatments for hematological malignancies should undergo HBV screening. In case of serological sign(s) of current or past infection with the virus, appropriate therapeutic or preventive strategies are suggested, according to both virological categories, risk of HBVr by immunosuppressive drugsand liver status. Either antiviral drug management and surveillance and pre-emptive approach are examined, commenting the current international recommendations about this debated issue.

Can physical activity eliminate the mortality risk associated with poor sleep?A 15-year follow-up of 341,248 MJ Cohort participants

Background:This study examined the joint associations of sleep patterns and physical activity(PA) with all-cause,cardiovascular disease(CVD),and cancer mortality.Methods:A total of 341,248 adults(mean age=39.7 years;men:48.3%) were included in the study,with a 15-year follow-up.Participants reported sleep duration and disturbances(difficulty falling asleep,easily awakened,or use of sleeping medication).PA was classified into 4 levels:<7.5,7.5-14.9,15.0-29.9,and>30.0 metabolic equivalent hours per week(MET-h/week).To understand the joint associations of sleep patterns and PA with mortality,Cox proportional hazard models were conducted,with exposure variables combining sleep duration/disturbances and PA.Results:Compared with the reference group(sleeping 6-8 h/day),individuals who slept>8 h/day had higher risk for all-cause mortality(hazard ratio(HR)=1.307,95% confidence interval(95%CI):1.248-1.369),CVD mortality(HR=1.298,95%CI:1.165-1.445),and cancer mortality(HR=1.128,95%CI:1.042-1.220).Short sleep duration was not associated with mortality risk.Increased risk of all-cause and CVD mortality was found in participants who had difficulty falling asleep(HR=1.120,95%CI:1.068-1.175;HR=1.163,95%CI:1.038-1.304,respectively),and used sleeping medication(HR=1.261,95%CI:1.159-1.372;HR=1.335,95%CI:1.102-1.618,respectively) compared with those who slept well.Long sleep duration and sleep disturbances were not associated with risk of all-cause and CVD mortality among individuals achieving a PA level of>15 MET-h/week,and in particular among those achieving> 30 MET-h/week.Conclusion:Long sleep duration,difficulty falling asleep,and use of sleeping medication were related to a higher risk of death.Being physically active at a moderate intensity for 25-65 min/day eliminated these detrimental associations.

Egocentric social network correlates of physical activity

Background:The social environment might play an important role in explaining people’s physical activity(PA)behavior.However,little is known regarding whether personal networks differ between physically active and physically inactive people.This study aimed to examine the relationship between personal network characteristics and adults’physical(in)activity.Methods:An egocentric social network study was conducted in a random sample in Switzerland(n=529,mean age of 53 years,54%females).Individual and personal network measures were compared between regular exercisers and non-exercisers.The extent of these factors’association with PA levels was also examined.Results:Non-exercisers(n=183)had 70%non-exercising individuals in their personal networks,indicating homogeneity,whereas regular exercisers(n=346)had 57%regularly exercising individuals in their networks,meaning more heterogeneous personal networks.Additionally,having more regular exercisers in personal networks was associated with higher PA levels,over and above individual factors.Respondents with an entirely active personal network reported,on average,1 day of PA more per week than respondents who had a completely inactive personal network.Other personal network characteristics,such as network size or gender composition,were not associated with PA.Conclusion:Non-exercisers seem to be clustered in inactive networks that provide fewer opportunities and resources,as well as less social support,for PA.To effectively promote PA,both individuals and personal networks need to be addressed,particularly the networks of inactive people(e.g.,by promoting group activities).

Lessons Learned from Aquifer Storage and Recovery (ASR) Systems in the United States

This paper is the result of a survey and analyses of available data from 204 Aquifer Storage and Recovery (ASR) sites in the United States. This ASR site survey included all active and inactive sites and collected both operational and construction details. The inactive sites are of particular interest here because these are the projects from which valuable lessons can often be learned. The intent of this paper is to examine the reasons for those projects that are terminated. Statistical analyses indicated that there were factors associated with terminated ASR projects: general geographic location (e.g., region), operational issue, storage cycle, casing material, and injection formation. The injection formation involves local geology and aquifer characteristics (i.e., whether the aquifer is leaky and/or unconfined, and if water can be displaced to surface water bodies or adjacent aquifers). Operational problems associated with inactive projects include well clogging, metals mobilization, a low percentage of recovery for injected water, and disinfection byproducts in the recovered water.

Study on Safety Analysis of Botanical Pesticides

Aiming at the safety problems of botanical pesticides currently ignored, the paper analyzes the unsafe factors existing in botanical pesticides from the three aspects of active ingredients, inactive ingredients and unregistered active ingredients, in order to provide a scientific reference for the safe use and effective su- pervision of botanical pesticides.

Physical fitness before and during the COVID-19 pandemic:Results of annual national physical fitness surveillance among 16,647,699 Japanese children and adolescents between 2013 and 2021

Background:Limited nationally representative evidence is available on temporal trends in physical fitness(PF)for children and adolescents during the coronavirus disease 2019(COVID-19)pandemic.The primary aim was to examine the temporal trends in PF for Japanese children and adolescents before and during the COVID-19 pandemic.The secondary aim was to estimate the concurrent trends in body size(measured as body mass and height)and movement behaviors(exercise,screen,and sleep time).Methods:Census PF data for children in Grade 5(aged 10-11 years)and adolescents in Grade 8(aged 13-14 years)were obtained for the years 2013-2021 from the National Survey of Physical Fitness,Athletic Performance,and Exercise Habits in Japan(n=16,647,699).PF and body size were objectively measured,and movement behaviors were self-reported.Using sample-weighted linear regression,temporal trends in mean PF were calculated before the pandemic(2013-2019)and during the pandemic(2019-2021)with adjustments for age,sex,body size,and exercise time.Results:When adjusted for age,sex,body size,and exercise time,there were significant declines in PF during the pandemic,with the largest declines observed in 20-m shuttle run(standardized(Cohen’s)effect size(ES)=-0.109 per annum(p.a.))and sit-ups performance(ES=-0.133p.a.).The magnitude of the declines in 20-m shuttle run and sit-ups performances were 18-and 15-fold larger,respectively,than the improvements seen before the pandemic(2013-2019),after adjusting for age,sex,body size,and exercise time.During the pandemic,both body mass and screen time significantly increased,and exercise time decreased.Conclusion:Declines in 20-m shuttle run and sit-ups performances suggest corresponding declines in population health during the COVID-19pandemic.

Predictive value of blood concentration of biologics on endoscopic inactivity in inflammatory bowel disease:A systematic review

BACKGROUND Although blood concentration of biologics is an important composition of disease management in inflammatory bowel disease(IBD)patients,complexity and uncertainty of biological management encourage many disputes in predicting the outcome of IBD patients through blood concentration of biologics.AIM To verify the predictive value of blood concentration of biologics on endoscopic inactivity in IBD patients under different situations.METHODS We searched PubMed/MEDLINE,Embase,and Web of Science up to May 2020 and identified IBD patients as the research cohort as well as the correlations between blood concentration of biologics and endoscopic inactivity in IBD patients as the research direction.RESULTS A total of 23 articles with 30 clinical studies and 1939 IBD patients were included.The predictive cut-off value of blood concentration of infliximab on mucosal healing should be 2.7-10.6μg/mL in IBD.Blood concentration of infliximab reaching 5.0-12.7μg/mL or more increased the probability of fistula healing/closure in perianal fistulizing Crohn's disease.Blood concentration of adalimumab reaching 7.2-16.2μg/mL or more could predict mucosal healing in IBD.The predictive cut-off value of blood concentration of adalimumab on fistula healing/closure should be 5.9-9.8μg/mL in perianal fistulizing Crohn's disease.Blood concentration of vedolizumab surpassing 25.0μg/mL indicated mucosal healing in ulcerative colitis patients under maintenance therapy and the predictive cut-off value of blood concentration on mucosal healing or endoscopic remission under induction therapy in IBD could be 8.0-28.9μg/mL.CONCLUSION Blood concentration of biologics should not be utilized to predict endoscopic inactivity of IBD independently due to discrepancies in clinical studies,whereas conducting therapeutic drug monitoring intensively contributes to precise therapy.

Assessment of physical activity status among pregnant women in southwestern China

Objective: To assess the patterns and intensities of physical activity among pregnant women in southwestern China, which help us create a fitness regimen based on the 2002 American College of Obstetricians and Gynecologists (ACOG) guidelines for exercise during pregnancy. Methods: A cross-sectional study was performed to recruit pregnant women at a prenatal checking visit clinic with the self-administered Chinese version of Pregnancy Physical Activity Questionnaire (PPAQ). Results: A total of 1179 Chinese pregnant women were enrolled, of whom 92.60% were classified as not meeting the ACOG guidelines. By intensity, 47.36% of the score was attributed to light-intensity activities (1.5 to <3.0 metabolic equivalent [MET]) in the first trimester;the other 2 trimesters were similar. By patterns, about 45.15% of the score was attributed to inactivity. More than 82.35% of enrolled pregnant women regarded slowly walking as the most common type of exercise during pregnancy. Conclusions: This study represents a group of Chinese women who maintained an inactive lifestyle, including low-intensity activities and unitary type of exercises during their pregnancy. Health-care providers are advised to provide appropriate physical activity guidelines to pregnant women. Development of MET-hours/week recommendations is warranted to promote greater physical activity during pregnancy.

Correlation between breast cancer and lifestyle within the Gulf Cooperation Council countries:A systematic review

BACKGROUND In the six Gulf Cooperation Council countries(GCCCs),Bahrain,Saudi Arabia,Kuwait,Oman,Qatar and the United Arab Emirates,breast cancer(BC)is the greatest cause of cancer incidence and mortality.Obesity and physical inactivity are established risk factors for BC globally and appear to be more of a problem in high income countries like the GCCCs.AIM To determine whether obesity and physical inactivity are associated with BC incidence in the GCCCs using the United Kingdom as a comparator.METHODS This systematic review was carried out according to PRISMA guidelines.A cancer registry and a statistical data search was done to identify the BC incidence over the past two decades and the prevalence of obesity and physical inactivity in the GCCCs.Additionally,a systematic search of the databases,MEDLINE,Web of Science,and PubMed between 1999 and 2019 was performed to determine whether obesity and physical inactivity are risk factors for BC in the GCCCs.All papers were critically appraised according to their research methods and were assessed for quality and risk of bias.RESULTS BC was the top malignancy in each GCC country.Women tended to be diagnosed with BC at a younger age than women in the United Kingdom.The greatest 10-year increase in BC incidence was seen in Saudi Arabia(54.2%),,approximately seven times the rate of increase seen in the United Kingdom(7.6%).The prevalence of obesity and physical inactivity was greater in all the GCCCs in comparison to the United Kingdom.A total of 155 full studies were reviewed of which 17 were included.Of those,eight looked at the prevalence of obesity and physical inactivity in the Gulf States and nine looked at these as risk factors for BC.Only one study found an association between BC and obesity(odds ratio=2.29).No studies looked solely at the link between physical inactivity and BC.CONCLUSION The prevalence of obesity and physical inactivity was high within the GCCCs,but the majority of the included studies found no positive correlation between obesity or physical inactivity and BC.A high proportion of women in this study were pre-menopausal which could contribute to the negative findings.

Regional and Synoptic-scale Features Associated with Inactive Periods of the Summer Monsoon over South China

This paper presents an observational study of the physical processes responsible for the inactive period (break) of the summer monsoon over South China (SC). The break of the monsoon is defined by using the rainfall data over Hong Kong Meteorological parameters provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) for the period 1985-1990 are examined. Daily values of each parameter for the six years are then composited each day for the period of 5 days before to 1 day after the break. It is found that several days before the break, changes opposite to those occurred during the onset and active periods begin to take place. This suggests that a feedback mechanism is present which tends to restore the atmosphere to a more stable state. This mechanism may be initiated by the formation of convective clouds during the onset and active periods. These clouds then reduce the solar radiation to the ground, leading to a gradual drop in the temperature. This drop, together with the cooling of the atmosphere due to the large amounts of rainfall, causes the pressure over the SC region to become higher, which in turn induces a westward extension of the subtropical ridge. The decrease in temperature over SC may also shift the location of the heat source to the west, which leads to a concomitant westward shift of the convergence of the southerlies and results in less moisture-laden air reaching the SC region. The atmosphere then becomes unfavourable for heavy convection and therefore a break starts.

The effect of electrochemically inactive Ti substituted for Ru in Li_(2)Ru_(1-x)Ti_xO_(3) on structure and electrochemical performance

The approach of substituting electrochemically active with inactive elements has widely been used to improve the electrochemical performance of Li-rich intercalation cathode materials. This especially is true for Li-rich compounds where almost all of the Li+ions are reversibly(de)intercalated during electrochemical cycling. The beneficial mechanism behind this substitution with electrochemically inactive elements is still not clear yet. Li_(2)RuO_(3) is chosen as basis for a model solid solution system to investigate the effect of electrochemically inactive elements owing to its high specific capacity of more than 300 m Ah g^(-1) and the significant contribution of anion redox mechanism. Herein, Li_(2)Ru_(1-x)Ti_xO_(3) solid solution series are synthesized and the effect of substituting with electrochemical inactive Ti for Ru on structure and electrochemical performance have been comprehensively investigated. The electrochemical performance is significantly improved, especially for Li_(2)Ru_(0.8)Ti_(0.2)O_(3), and the capacity retention after 50 cycles increases from 81% to 90%, as compared to the end member Li_(2)RuO_(3). Results of electrochemical impedance spectroscopy show that Ti substitution reduces the charge transfer impedance, which favors the Li+diffusion across the electrolyte–electrode interface and improves the electronic conductivity. For the first time,nuclear magnetic resonance was utilized to confirm that a small part of Ti ions exchange their position with Li ions in the Li layer. This research provides a better understanding of electrochemical inactive element substitution and strong insights for the functional design of the next generation of Li-rich cathode materials.

The financial burden of physical inactivity

According to the World Health Organization,"physical inactivity has been identified as the fourth leading risk factor for global mortality causing an estimated 3.2 million (annual)deaths globally.”1 In the Research Highlight of the first issue of this journal,I reviewed the evidence which supports the notion that physical inactivity can cost lives,in terms of longevity and quality of life,especially in the last few years of our lives.2 Here,I would like to review the literature that reveals the financial burden due to physical inactivity.

Possible Factors Involved in Oral Inactivity of Meropenem, a Carbapenem Antibiotic

Meropenem, a carbapenem antibiotic, is inactive after oral administration and administered exclusively by injection. In this study, in order to address the factors involved in the oral inactivity of meropenem, in vitro permeation characteristics across rat ileal segments was investigated using diffusion cells. Moreover, stability of meropenem was evaluated in the Japanese Pharmacopoeia (JP) 1st and 2nd fluid for disintegration test. Cefotaxime, ceftibuten, and faropenem were used for comparison. The permeation of meropenem across rat ileal segments was approximately 5-fold greater in secretory direction than in absorptive direction. The secretory-oriented transport of meropenem markedly diminished by replacement of D-glucose in the experimental medium with unmetabolizing 3-O-methyl-D-glucose, suggesting that the secretory transport of meropenem was an energy-dependent process. Cefotaxime exhibited extensively secretory-oriented permeation. On the other hand, much weaker directionalities were observed in ceftibuten and faropenem. While meropenem as well as other three β-lactam antibiotics was stable in JP 2nd fluid (pH 6.8), it declined rapidly in JP 1st fluid (pH 1.2). These results suggest that, in addition to the hydrophilic property of meropenem, its instability at gastric pH and secretory transport in the small intestine are possible factors involved in the inactivity of meropenem after oral administration.