Avalanches and Extreme Value Statistics of a Mesoscale Moving Contact Line.

We report direct atomic force microscopy measurements of pinning-depinning dynamics of a circular moving contact line (CL) over the rough surface of a micron-sized vertical hanging glass fiber, which intersects a liquid-air interface. The measured capillary force acting on the CL exhibits sawtoothlike fluctuations, with a linear accumulation of force of slope k (stick) followed by a sharp release of force δf, which is proportional to the CL slip length. From a thorough analysis of a large volume of the stick-slip events, we find that the local maximal force F_{c} needed for CL depinning follows the extreme value statistics and the measured δf follows the avalanche dynamics with a power law distribution in good agreement with the Alessandro-Beatrice-Bertotti-Montorsi (ABBM) model. The experiment provides an accurate statistical description of the CL dynamics at mesoscale, which has important implications to a common class of problems involving stick-slip motion in a random defect or roughness landscape.

Statistical laws of stick-slip friction at mesoscale.

Friction between two rough solid surfaces often involves local stick-slip events occurring at different locations of the contact interface. If the apparent contact area is large, multiple local slips may take place simultaneously and the total frictional force is a sum of the pinning forces imposed by many asperities on the interface. Here, we report a systematic study of stick-slip friction over a mesoscale contact area using a hanging-beam lateral atomic-force-microscope, which is capable of resolving frictional force fluctuations generated by individual slip events and measuring their statistical properties at the single-slip resolution. The measured probability density functions (PDFs) of the slip length δxs, the maximal force Fc needed to trigger the local slips, and the local force gradient [Formula: see text] of the asperity-induced pinning force field provide a comprehensive statistical description of stick-slip friction that is often associated with the avalanche dynamics at a critical state. In particular, the measured PDF of δxs obeys a power law distribution and the power-law exponent is explained by a new theoretical model for the under-damped spring-block motion under a Brownian-correlated pinning force field. This model provides a long-sought physical mechanism for the avalanche dynamics in stick-slip friction at mesoscale.

Escaping speed of bacteria from confinement.

Microswimmers such as bacteria exhibit large speed fluctuation when exploring their living environment. Here, we show that the bacterium Escherichia coli with a wide range of length speeds up beyond its free-swimming speed when passing through narrow and short confinement. The speedup is observed in two modes: for short bacteria with L <20 µm, the maximum speed occurs when the cell body leaves the confinement, but a flagellar bundle is still confined. For longer bacteria (L ≥ 20 µm), the maximum speed occurs when the middle of the cell, where the maximum number of flagellar bundles locate, is confined. The two speed-up modes are explained by a vanishing body drag and an increased flagella drag-a universal property of an "ideal swimmer." The spatial variance of speed can be quantitatively explained by a simple model based on the resistance matrix of a partially confined bacterium. The speed change depends on the distribution of motors, and the latter is confirmed by fluorescent imaging of flagellar hooks. By measuring the duration of slowdown and speedup, we find that the effective chemotaxis is biased in filamentous bacteria, which might benefit their survival. The experimental setup can be useful to study the motion of microswimmers near surfaces with different surface chemistry.

Utility of Acute Physiology and Chronic Health Evaluation (APACHE II) in Predicting Mortality in Patients with Pyogenic Liver Abscess: A Retrospective Study.

Pyogenic liver abscess (PLA) is a major life-threatening disease with varied clinical features. This study aimed to determine predictors of mortality in patients with PLA using criteria determined upon admission. We retrospectively examined the data of 324 hospitalized adults in whom liver abscesses were confirmed using abdominal ultrasound and/or computed tomography. The relationship between various risk factors was assessed using multivariate analysis. A total of 109 (33.6%) patients were admitted to the intensive care unit (ICU). The overall mortality rate was 7.4% and was higher among ICU patients than non-ICU patients (21.1% vs. 0.5%, p < 0.001). PLA patients with an Acute Physiology and Chronic Health Evaluation (APACHE) II score ≥18 had a 19.31-fold increased risk, and those with concomitant infections had a 34.33-fold increased risk of 30-day mortality according to multivariate analysis. The estimated area under the receiver operating characteristic curve for predicting 30-day mortality revealed that APACHE II score ≥18 (sensitivity of 75% and specificity of 84%, p < 0.0001) had better discriminative power than Sequential Organ Failure Assessment (SOFA) ≥6 (sensitivity of 81% and specificity of 66%, p < 0.0001). APACHE II has shown better discrimination ability than SOFA in predicting mortality in PLA patients. To improve outcomes in patients with PLA, future management strategies should focus on high-risk patients.

Wetting Dynamics of a Lipid Monolayer.

Direct measurement and control of the dynamic wetting properties of a lipid-coated water-air interface over a wide range of surface tension variations have many important applications. However, the wetting dynamics of the interface near its partial-to-complete wetting transition has not been fully understood. Here, we report a systematic study of the wetting dynamics of a lipid-coated water-air interface around a thin glass fiber of diameter 1-5 µm and length 100-300 µm. The glass fiber is glued onto the front end of a rectangular cantilever to form a "long-needle" atomic-force-microscope probe. Three surface modifications are applied to the glass fiber to change its wetting properties from hydrophilic to hydrophobic. A monolayer of phospholipid dipalmitoylphosphatidylcholine (DPPC) is deposited on the water-air interface in a homemade Langmuir-Blodgett trough, and the surface tension γL of the DPPC-coated water-air interface is varied in the range of 2.5 ≲ γL ≲ 72 mN/m. From the measured hysteresis loop of the capillary force for the three coated fiber surfaces with varying γL, we observe a sharp transition from partial to complete wetting when γL is reduced to a critical value (γL)c. The obtained values of (γL)c are 27 ± 1 mN/m for a DPPC-coated fiber surface and 23 ± 1 mN/m for an trichloro(1H,1H,2H,2H-perfluorooctyl) silane (FTS)-coated surface. Below (γL)c, the contact angle θ0 of the liquid interface is found to be zero for both hydrophobic fiber surfaces and the corresponding spreading parameter S becomes positive. For the FTS-coated fiber surface, the height of capillary rise exhibits a jump when γL is reduced to (γL)c, which indicates that a rapidly advancing liquid film is formed on the fiber surface when the partial-to-complete wetting transition takes place. Our experiment thus establishes a quantitative method by which many other liquid interfaces coated with polymers, surfactants, and biomolecules (such as proteins and lipids) may be characterized dynamically.

Symptomatic cholelithiasis patients have an increased risk of pancreatic cancer: A population-based study.

BACKGROUND AND AIM: Pancreatic cancer is a fatal disease; currently, the risk factor survey is not suitable for sporadic pancreatic cancer, which has neither family history nor the genetic analysis data. The aim of the present study was to evaluate the roles of cholelithiasis and cholelithiasis treatments on pancreatic cancer risk. METHODS: Symptomatic adult patients with an index admission of cholelithiasis were selected from one million random samples obtained between January 2005 and December 2009. The control group was matched with a 1:1 ratio for sex, age, chronic pancreatitis, and pancreatic cystic disease. Subsequent pancreatic cancer, which we defined as pancreatic cancer that occurred ≥ 6 months later, and total pancreatic cancer events were calculated in the cholelithiasis and control groups. The cholelithiasis group was further divided into endoscopic sphincterotomy/endoscopic papillary balloon dilatation, cholecystectomy, endoscopic sphincterotomy/endoscopic papillary balloon dilatation and cholecystectomy, and no-intervention groups for evaluation. RESULTS: The cholelithiasis group and the matched control group included 8265 adults. The cholelithiasis group contained 86 cases of diagnosed pancreatic cancer, and the control group contained 8 cases (P < 0.001). The incidence rate ratio (IRR) of subsequent pancreatic cancer was significantly higher in the cholelithiasis group than in the control group (IRR: 5.28, P < 0.001). The IRR of subsequent pancreatic cancer was higher in the no-intervention group comparing with cholecystectomy group (IRR = 3.21, P = 0.039) but was similar in other management subgroups. CONCLUSION: Symptomatic cholelithiasis is a risk factor for pancreatic cancer; the risk is similar regardless of the intervention chosen for cholelithiasis.

Cholecystectomy reduces subsequent cholangiocarcinoma risk in choledocholithiasis patients undergoing endoscopic intervention.

BACKGROUND: Cholangiocarcinoma is a disease with a high mortality rate. Our previous study revealed that cholelithiasis patients who undergo endoscopic sphincterotomy (ES)/endoscopic papillary balloon dilatation are at a higher risk for subsequent cholangiocarcinoma than cholelithiasis patients who undergo cholecystectomy. AIM: To clarify the relationship between recurrent biliary events and subsequent cholangiocarcinoma risk in choledocholithiasis patients. METHODS: From one million random cases in the Taiwan National Health Insurance Research Database 2004-2011, we selected symptomatic choledocholithiasis patients older than 18 years who were admitted from January 2005 to December 2009 (study group). Cases for a control group were defined as individuals who had never been diagnosed with cholelithiasis, matched by sex and age in a 1:3 ratio. The study group was further divided into ES/endoscopic papillary balloon dilatation, both ES/endoscopic papillary balloon dilatation and cholecystectomy, and no intervention groups. RESULTS: We included 2096 choledocholithiasis patients without previous intervention or cholangiocarcinoma. A total of 12 (2.35%), 11 (0.74%), and 1 (1.00%) subsequent cholangiocarcinoma cases were diagnosed among 511 ES/endoscopic papillary balloon dilatation patients, 1485 patients with no intervention, and 100 ES/endoscopic papillary balloon dilatation and cholecystectomy patients, respectively. The incidence rates of recurrent biliary event were 527.79/1000 person-years and 286.69/1000 person-years in the subsequent cholangiocarcinoma and no cholangiocarcinoma group, showing a high correlation between subsequent cholangiocarcinoma risk and recurrent biliary events. CONCLUSION: Choledocholithiasis patients who undergo further cholecystectomy after ES/endoscopic papillary balloon dilatation have decreased subsequent cholangiocarcinoma risk due to reduced recurrent biliary events.

Dynamics of a membrane coupled to an active fluid.

The dynamics of a membrane coupled to an active fluid on top of a substrate is considered theoretically. It is assumed that the director field of the active fluid has rotational symmetry in the membrane plane. This situation is likely to be relevant for in vitro reconstructed actomyosin-membrane system. Different from a membrane coupled to a polar active fluid, this model predicts that only when the viscosity of the fluid above the membrane is sufficiently large, a contractile active fluid is able to slow down the relaxation of the membrane for perturbations with wavelength comparable to the thickness of the active fluid. Hence, our model predicts a finite-wavelength instability in the limit of strong contractility, which is different from a membrane coupled to a polar active fluid. However, a membrane coupled to an extensile active fluid is always unstable against long-wavelength perturbations due to active extensile stress enhanced membrane undulation.

Favorable gallbladder cancer mortality-to-incidence ratios of countries with good ranking of world's health system and high expenditures on health.

BACKGROUND: The mortality-to-incidence ratio (MIR) is a marker that reflects the clinical outcome of cancer treatment. MIR as a prognostic marker is more accessible when compared with long-term follow-up survival surveys. Theoretically, countries with good health care systems would have favorable outcomes for cancer; however, no report has yet demonstrated an association between gallbladder cancer MIR and the World's Health System ranking. METHODS: We used linear regression to analyze the correlation of MIRs with the World Health Organization (WHO) rankings and total expenditures on health/gross domestic product (e/GDP) in 57 countries selected according to the data quality. RESULTS: The results showed high crude rates of incidence/mortality but low MIR in more developed regions. Among continents, Europe had the highest crude rates of incidence/mortality, whereas the highest age-standardized rates (ASR) of incidence/mortality were in Asia. The MIR was lowest in North America and highest in Africa (0.40 and 1.00, respectively). Furthermore, favorable MIRs were correlated with good WHO rankings and high e/GDP (p = 0.01 and p = 0.030, respectively). CONCLUSIONS: The MIR variation for gallbladder cancer is therefore associated with the ranking of the health system and the expenditure on health.

Enterotype-based Analysis of Gut Microbiota along the Conventional Adenoma-Carcinoma Colorectal Cancer Pathway.

The dysbiosis of human gut microbiota is strongly associated with the development of colorectal cancer (CRC). The dysbiotic features of the transition from advanced polyp to early-stage CRC are largely unknown. We performed a 16S rRNA gene sequencing and enterotype-based gut microbiota analysis study. In addition to Bacteroides- and Prevotella-dominated enterotypes, we identified an Escherichia-dominated enterotype. We found that the dysbiotic features of CRC were dissimilar in overall samples and especially Escherichia-dominated enterotype. Besides a higher abundance of Fusobacterium, Enterococcus, and Aeromonas in all CRC faecal microbiota, we found that the most notable characteristic of CRC faecal microbiota was a decreased abundance of potential beneficial butyrate-producing bacteria. Notably, Oscillospira was depleted in the transition from advanced adenoma to stage 0 CRC, whereas Haemophilus was depleted in the transition from stage 0 to early-stage CRC. We further identified 7 different CAGs by analysing bacterial clusters. The abundance of microbiota in cluster 3 significantly increased in the CRC group, whereas that of cluster 5 decreased. The abundance of both cluster 5 and cluster 7 decreased in the Escherichia-dominated enterotype of the CRC group. We present the first enterotype-based faecal microbiota analysis. The gut microbiota of colorectal neoplasms can be influenced by its enterotype.

Pattern formation of skin cancers: Effects of cancer proliferation and hydrodynamic interactions.

We study pattern formation of skin cancers by means of numerical simulation of a binary system consisting of cancer and healthy cells. We extend the conventional model H for macrophase separations by considering a logistic growth of cancer cells and also a mechanical friction between dermis and epidermis. Importantly, our model exhibits a microphase separation due to the proliferation of cancer cells. By numerically solving the time evolution equations of the cancer composition and its velocity, we show that the phase separation kinetics strongly depends on the cell proliferation rate as well as on the strength of hydrodynamic interactions. A steady-state diagram of cancer patterns is established in terms of these two dynamical parameters and some of the patterns correspond to clinically observed cancer patterns. Furthermore, we examine in detail the time evolution of the average composition of cancer cells and the characteristic length of the microstructures. Our results demonstrate that different sequence of cancer patterns can be obtained by changing the proliferation rate and/or hydrodynamic interactions.

Risk of cholangiocarcinoma in patients undergoing therapeutic endoscopic retrograde cholangiopancreatography or cholecystectomy: A population based study.

BACKGROUND: Cholangiocarcinoma is a highly lethal disease that had been underestimated in the past two decades. Many risk factors are well documented for in cholangiocarcinoma, but the impacts of advanced biliary interventions, like endoscopic sphincterotomy (ES), endoscopic papillary balloon dilatation (EPBD), and cholecystectomy, are inconsistent in the previous literature. AIM: To clarify the risks of cholangiocarcinoma after ES/EPBD, cholecystectomy or no intervention for cholelithiasis using the National Health Insurance Research Database (NHIRD). METHODS: From data of NHIRD 2004-2011 in Taiwan, we selected 7938 cholelithiasis cases as well as 23814 control group cases (matched by sex and age in a 1:3 ratio). We compared the previous risk factors of cholangiocarcinoma and cholangiocarcinoma rate in the cholelithiasis and control groups. The incidences of total and subsequent cholangiocarcinoma were calculated in ES/EPBD patients, cholecystectomy patients, cholelithiasis patients without intervention, and groups from the normal population. RESULTS: In total, 537 cases underwent ES/EPBD, 1743 cases underwent cholecystectomy, and 5658 cholelithiasis cases had no intervention. Eleven (2.05%), 37 (0.65%), and 7 (0.40%) subsequent cholangiocarcinoma cases were diagnosed in the ES/EPBD, no intervention, and cholecystectomy groups, respectively, and the odds ratio for subsequent cholangiocarcinoma was 3.13 in the ES/EPBD group and 0.61 in the cholecystectomy group when compared with the no intervention group. CONCLUSION: In conclusion, symptomatic cholelithiasis patients who undergo cholecystectomy can reduce the incidence of subsequent cholangiocarcinoma, while cholelithiasis patients who undergo ES/EPBD are at a great risk of subsequent cholangiocarcinoma according to our findings.

Role of Cholecystectomy in Choledocholithiasis Patients Underwent Endoscopic Retrograde Cholangiopancreatography.

There are no clinical guidelines for the timing of cholecystectomy (CCY) after performing therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for choledocholithiasis. We tried to analyze the clinical practice patterns, medical expenses, and subsequent outcomes between the early CCY, delayed CCY, and no CCY groups of patients. 1827 choledocholithiasis patients who underwent therapeutic ERCP were selected from the nationwide population databases of two million random samples. These patients were further divided into early CCY, delayed CCY, and no CCY performed. In our analysis, 1440 (78.8%) of the 1827 patients did not undergo CCY within 60 days of therapeutic ERCP, and only 239 (13.1%) patients underwent CCY during their index admission. The proportion of laparoscopic CCY increased from 37.2% to 73.6% in the delayed CCY group. There were no significant differences (p = 0.934) between recurrent biliary event (RBE) rates with or without early CCY within 60 days of ERCP. RBE event-free survival rates were significantly different in the early CCY (85.04%), delayed CCY (89.54%), and no CCY (64.45%) groups within 360 days of ERCP. The method of delayed CCY can reduce subsequent RBEs and increase the proportion of laparoscopic CCY with similar medical expenses to early CCY in Taiwan's general practice environment.

Major bleeding risk of endoscopic sphincterotomy versus endoscopic papillary balloon dilatation in hemodialysis patients.

BACKGROUND/AIMS: Endoscopic sphincterotomy (EST) and endoscopic papillary balloon dilatation (EPBD) are used for therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The postprocedure bleeding rate for EPBD is low in the normal population; however, this bleeding rate in a group of patients prone to bleeding, such as patients with end-stage renal disease, is not well-established. We therefore evaluated the post-EST and post-EPBD bleeding rate among hemodialysis (HD) patients based on data from Taiwan's National Health Insurance Research Database (NHIRD). PATIENTS AND METHODS: The NHIRD entries for a population of 2 million were screened for patients who had a catastrophic illness card for HD between 1st January 2004 and 31st December 2011 and these patients were enrolled as research subjects. The rates of major gastrointestinal tract bleeding events appearing within 14 days after EST or EPBD were compared between HD and non-HD patients. RESULTS: A total of 3561 patients, over 18 years of age and without liver cirrhosis or hematologic diseases, underwent 3826 EST and 280 EPBD procedures during the 8 calendar years selected for our analysis. The total post-ERCP major bleeding rate was much higher in HD than in non-HD patients (8.64% vs. 2.16%, P < 0.0001). The rate of postprocedure major bleeding events was lower for non-HD patients who underwent EPBD than those who underwent EST (0.75% vs. 2.26%; P = 0.049), whereas the postprocedure major bleeding event rates were similar in HD patients who underwent either EPBD or EST (8.70% vs. 8.33%; P = 0.484). CONCLUSION: Post-ERCP, post-EST, and post-EPBD major bleeding rates were all higher in HD patients in this study. EPBD resulted in lower postprocedure major bleeding events than EST in the non-HD population, but it failed to provide the reduction in bleeding events needed to perform endoscopic hemostasis in HD patients.

Hydrodynamic interaction induced breakdown of the state properties of active fluids.

The mechanical pressure of active fluids in which swimmers are modeled by soft run-and-tumble spheres is investigated by dissipative particle dynamics simulations. The incremental pressure (Π) with respect to the system pressure with inactive swimmers comprises the direct contribution of the swimmers (π) and the indirect contribution of fluids associated with hydrodynamic interactions (HIs). The pressure can be determined from the bulk and confining wall and the former is always less than the latter. The π of dilute active dispersions is proportional to their active diffusivity while Π grows generally with propulsive force and run time. However, Π is always substantially less than π because of negative contributions to pressure by HIs. The wall pressure depends on the swimmer-wall interactions, verifying that pressure is not a state function for active spheres due to the HIs. Owing to the distinct flow patterns, Π varies with the swim-type (pusher and puller) subject to the same run-and-tumble parameters at high concentrations.

Mechanical pressure, surface excess, and polar order of a dilute rod-like nanoswimmer suspension: role of swimmer-wall interactions.

The mechanical pressure, surface excess, and polar order of a dilute rod-like nanoswimmer suspension confined by two parallel plates are explored by dissipative particle dynamics. The accumulation and preferred orientation of swimmers near the walls are distinctly shown through the density and polar order distributions for various active force, Fa, values and rod lengths. As Fa is increased, it is interesting to observe that there exists a maximum of the polar order, revealing that the dominant mechanism of the swimmer behavior can be altered by the coupling between the active force and the rod-wall interaction. As a result, the influences of the active force on the swim pressure Π(w)a contributed by the swimmers directly and the surface excess Γ* can be classified into two scaling regimes, natural rotation (weak propulsion) and forced rotation (strong propulsion). Π(w)a and Γ* are proportional to Fa2 in the former regime but become proportional to Fa in the latter regime. For all rod-wall repulsions, the swim pressure of active rods in confined systems Π(w)a always differs from that in unbounded systems Π(b)a which is simply proportional to Fa2 associated with the active diffusivity. That is, unlike thermal equilibrium systems, Π(w)a is not a state function because of the presence of the wall-torque.

Health disparities are associated with gastric cancer mortality-to-incidence ratios in 57 countries.

AIM: To evaluate the association between mortality-to-incidence ratios (MIRs) and health disparities. METHODS: In this study, we used the GLOBOCAN 2012 database to obtain the cancer incidence and mortality data for 57 countries, and combined this information with the World Health Organization (WHO) rankings and total expenditures on health/gross domestic product (e/GDP). The associations between variables and MIRs were analyzed by linear regression analyses and the 57 countries were selected according to their data quality. RESULTS: The more developed regions showed high gastric cancer incidence and mortality crude rates, but lower MIR values than the less developed regions (0.64 vs 0.80, respectively). Among six continents, Oceania had the lowest (0.60) and Africa had the highest (0.91) MIR. A good WHO ranking and a high e/GDP were significantly associated with low MIRs (P = 0.001 and P = 0.001, respectively). CONCLUSION: The MIR variation for gastric cancer would predict regional health disparities.

Favorable liver cancer mortality-to-incidence ratios of countries with high health expenditure.

OBJECTIVE: Health expenditure is a marker associated with an advanced healthcare system, which contributes toward the good prognosis of patients. Mortality-to-incidence ratios (MIRs) are one of the predictors that reflect the prognosis of cancer patients. There remains some uncertainty on the correlation of MIRs of liver cancer with the health expenditure of countries. METHODS: We therefore analyzed the correlation of MIRs from the GLOBOCAN 2012 database with the WHO rankings and the total expenditures on health/gross domestic product from WHO by linear regression analyses. A total of 29 countries were selected in this study according to the data quality and the incidence number. RESULTS: The results showed high rates of incidence/mortality and MIRs in less developed regions (0.92 vs. 0.96 for more vs. less developed regions). Among the continents, Asia has the highest incidence/mortality in case number, crude rate, and age-standardized rate. In terms of the MIR, Northern America has the lowest MIR and Latin America and the Caribbean have the highest MIRs (0.82 and 1.04, respectively). Finally, favorable MIRs are associated significantly with good WHO ranking and high expenditures on gross domestic product (P=0.048 and 0.025, respectively). CONCLUSION: The MIR variation for liver cancer is thus found to be associated with the health expenditure and WHO ranking.

Musashi-1 promotes a cancer stem cell lineage and chemoresistance in colorectal cancer cells.

Colorectal cancers (CRCs) are a critical health issue worldwide. Cancer stem cell (CSC) lineages are associated with tumour transformation, progression, and malignant transformation. However, how lineages are transformed and how chemoresistance is acquired by CRCs remain largely unknown. In this report, we demonstrated that the RNA-binding protein Musashi-1 enhanced the development of CD44+ colorectal CSCs and triggered the formation of anti-apoptotic stress granules (SGs). Our results indicated that CD44+ CSC lineage-specific induction of tumour malignancies was controlled by Musashi-1. In addition, Musashi-1 formed SGs when CRC cell lines were treated with 5-fluorouracil. The C-terminal domain of Musashi-1 was critical for recruitment of Musashi-1 into SGs. Intracellular Musashi-1 SGs enhanced the chemoresistance of CRCs. Analysis of clinical CRC samples indicated that Musashi-1 expression was prominent in CRC stage IIA and IIB. In summary, we demonstrated that Musashi-1, a stemness gene, is a critical modulator that promotes the development of CD44+ colorectal CSCs and also enhances CRC chemoresistance via formation of SGs. Our findings elucidated a novel mechanism of CRC chemoresistance through increased anti-apoptotic effects via Musashi-1-associated SGs.

Directed drift and fluid pumping of nanoswimmers by periodic rectification-diffusion.

The steady ratchet transport of run-and-tumble nanoswimmers in a 3D microfluidic channel constructed by periodic chambers separated by half-cylinder funnels is explored by dissipative particle dynamics. Two regions in a chamber are identified: rectification and active diffusion. While the concentration gradient is driven by the concentration jump in the rectification region, the ratchet current is dominated by the diffusion rate in the active diffusion region, which is classified into normal and Knudsen types. The former obeys Fick's law and is proportional to va2τ, where va is the self-propulsion velocity and τ the run time. In addition, autonomous pumping of fluids is induced by aligned force dipoles associated with nanoswimmers accumulated near funnels, similar to the mechanism of bacteria carpet. The direction of fluid flow is the same as that of the ratchet current but the former is one order of magnitude smaller than the latter. Thus, the fluid velocity depends on the characteristics of nanoswimmers.