Collective self-optimization of binary mixed heterogeneous populations.

To maximize the survival chances of society members, collective self-organization must balance individual interests with promoting the collective welfare. Although situations where group members have equal optimal values are clear, how varying optimal values impacts group dynamics remains unclear. To address this gap, we conducted a self-optimization study of a binary system incorporating communication-enabled active particles with distinct optimal values. We demonstrate that similar particles will spontaneously aggregate and separate from each other to maximize their individual benefits during the process of self-optimization. Our research shows that both types of particles can produce the optimal field values at low density. However, only one type of particle can achieve the optimal field values at medium density. At high densities, neither type of particle is effective in reaching the optimal field values. Interestingly, we observed that during the self-optimization process, the mixture demixed spontaneously under certain circumstances of mixed particles. Particles with higher optimal values developed into larger clusters, while particles with lower optimal values migrated outside of these clusters, resulting in the separation of the mixture. To achieve this separation, suitable noise intensity, particle density, and the significant difference in optimal values were necessary. Our results provide a more profound comprehension of the self-optimization of synthetic or biological agents' communication and provide valuable insight into separating binary species and mixtures.

Reordering and synchronization of electrical turbulence in cardiac tissue through global and partial optogenetical illumination.

Electrical turbulence in the heart is considered the culprit of cardiac disease, including the fatal ventricular fibrillation. Optogenetics is an emerging technology that has the capability to produce action potentials of cardiomyocytes to affect the electric wave propagation in cardiac tissue, thereby possessing the potential to control the turbulence, by shining a rotating spiral pattern onto the tissue. In this paper, we present a method to reorder and synchronize electrical turbulence through optogenetics. A generic two-variable reaction-diffusion model and a simplified three-variable ionic cardiac model are used. We discuss cases involving either global or partial illumination.

Active colloids under geometrical constraints in viscoelastic media.

We study the behavior of active particles (APs) moving in a viscoelastic fluid in the presence of geometrical confinements. Upon approaching a flat wall, we find that APs slow down due to compression of the enclosed viscoelastic fluid. In addition, they receive a viscoelastic torque leading to sudden orientational changes and departure from walls. Based on these observations, we develop a numerical model which can also be applied to other geometries and yields good agreement with experimental data. Our results demonstrate, that APs are able to move through complex geometrical structures more effectively when suspended in a viscoelastic compared to a Newtonian fluid.

[Degradation Characteristics of Antibiotics During Composting of Four Types of Feces].

The widespread use of antibiotics in feed results in a large number of antibiotic residues in feces. Composting technology can degrade these residual antibiotics. A pilot-scale aerobic composting device was used to analyze the antibiotic residues and composting degradation characteristics of four types of feces (maggot manure, chicken manure, pig manure, and cow manure). Results showed that sulfonamides (SAs), fluoroquinolones (FQs), tetracycline (TCs), and macrolides (MAs) were the main antibiotics, and different type of feces had different dominant antibiotics. The contents of FQs and oxytetracycline (OTC) were none on the seventh day of the compost, and their degradation rates were the fastest. After composting, the degradation rate of doxycycline (DOX) in the four types of fecal composts was more than 85%. Meanwhile, the degradation rates of SAs in chicken, pig, and cow manure composts were also more than 80%, which was much lower in the one in maggot manure compost. MAs were only found in maggot manure, and the degradation rate was 70.79% after composting. Correlation analysis indicated that the water content and bulk density were the most important environmental factors affecting the degradation rates of antibiotics in the four types of fecal composts.

Rectification and separation of mixtures of active and passive particles driven by temperature difference.

Transport and separation of binary mixtures of active and passive particles are investigated in the presence of temperature differences. It is found that temperature differences can strongly affect the rectification and separation of the mixtures. For active particles, there exists an optimal temperature difference at which the rectified efficiency is maximal. Passive particles are not propelled and move by collisions with active particles, so the response to temperature differences is more complicated. By changing the system parameters, active particles can change their directions, while passive particles always move in the same direction. The simulation results show that the separation of mixtures is sensitive to the system parameters, such as the angular velocity, the temperature difference, and the polar alignment. The mixed particles can be completely separated under certain conditions.

Giant negative mobility of inertial particles caused by the periodic potential in steady laminar flows.

Transport of an inertial particle advected by a two-dimensional steady laminar flow is numerically investigated in the presence of a constant force and a periodic potential. Within particular parameter regimes, this system exhibits absolute negative mobility, which means that the particle can travel in a direction opposite to the constant force. It is found that the profile of the periodic potential plays an important role in the nonlinear response regime. Absolute negative mobility can be drastically enhanced by applying appropriate periodic potential, the parameter regime for this phenomenon becomes larger and the amplitude of negative mobility grows exceedingly large (giant negative mobility). In addition, giant positive mobility is also observed in the presence of appropriate periodic potential.

Transport of particles driven by the traveling obstacle arrays.

Transport of three types of particles (passive particles, active particles without polar interaction, and active particles with polar interaction) is numerically investigated in the presence of traveling obstacle arrays. The transport behaviors are different for different types of particles. For passive particles, there exists an optimal traveling speed (or the translational diffusion) at which the average velocity of particles takes its maximum value. For active particles without polar interaction, the average velocity of particles is a peaked function of the obstacle traveling speed. The average velocity decreases monotonically with increase of the rotational diffusion for large driving speed, while it is a peaked function of the rotational diffusion for small driving speed. For active particles with polar interaction, interestingly, within particular parameter regimes, active particles can move in the opposite direction to the obstacles. The average velocity of particles can change its direction by changing the system parameters (the obstacles driving speed, the polar interaction strength, and the rotational diffusion).

Transport and diffusion of paramagnetic ellipsoidal particles in a rotating magnetic field.

Transport and diffusion of paramagnetic ellipsoidal particles under the action of a rotating magnetic field are numerically investigated in a two-dimensional channel. It is found that paramagnetic ellipsoidal particles in a rotating magnetic field can be rectified in the upper-lower asymmetric channel. The transport and the effective diffusion coefficient are much more different and complicated for active particles, while they have similar behaviors and change a little when applying rotating magnetic fields of different frequencies for passive particles. For active particles, the back-and-forth rotational motion facilitates the effective diffusion coefficient and reduces the rectification, whereas the rotational motion synchronous with the magnetic field suppresses the effective diffusion coefficient and enhances the rectification. There exist optimized values of the parameters (the anisotropic degree, the amplitude and frequency of magnetic field, the self-propelled velocity, and the rotational diffusion rate) at which the average velocity and diffusion take their maximal values. Particles with different shapes, self-propelled speeds, or rotational diffusion rates will move to the opposite directions and can be separated by applying rotating magnetic fields of suitable strength and frequency. Our results can be used to separate particles, orient the particles along any direction at will during motion, and control the particle diffusion.

Transport of alignment active particles in funnel structures.

We study the transport of alignment active particles in complex confined structures (an array of asymmetric funnels). It is found that due to the existence of the multiple pathways, the alignment interaction can enrich the transport behavior of active particles. In an array of asymmetric funnels, the purely nematic alignment always suppresses the rectification. However, the polar alignment does not always promote the rectification, the rectification is suppressed for large self-propulsion speed. In addition, we also found the existence of optimal parameters (the self-propulsion speed and the rotational diffusion coefficient) at which the directed velocity takes its maximal value.

[Review on the main microorganisms and their metabolic mechanisms in enhanced biological phosphorus removal (EBPR) systems].

Enhanced biological phosphorus removal (EBPR) process is applied widely for removing phosphorus from wastewater. Studies on functional microorganisms and their metabolic mechanisms are fundamental to effective regulation for stable operation and performance improvement of EBPR process. Two main types of microorganisms in EBPR systems, polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) were selected to summarize their metabolic mechanisms such as substrate uptake mechanisms, glycogen degradation pathways, extent of TCA cycle involvement and metabolic similarity between PAOs and GAOs. Application of molecular biology techniques in microbiology and metabolic mechanisms involved in the EBPR system was evaluated. Potential future research areas for the EBPR system and process optimization were also proposed.

Improving Anammox start-up with bamboo charcoal.

Three Upflow Anaerobic Sludge Blanket (UASB) reactors were compared for Anammox enrichment using synthetic wastewater with Spherical Plastic (SP) and Bamboo Charcoal (BC) addition, and without carrier (CK). After four months of operation, the Anammox activity occurred in all reactors allowing continuous removal of ammonium and nitrite. Ammonium and nitrite removal efficiencies were all higher than 98% in steady phase with the effluent concentrations below 1 mg L(-1). The start-up time could be shortened from 117 to 97 d in CK and SP reactor to 85 d in BC amendment reactor. Quantitative PCR (q-PCR) analyses indicated a significant increase in the number of Anammox bacteria in BC amended reactor as compared with CK and SP during the entire start-up periods. The copy numbers of Anammox of 16S rRNA gene in the reactor with BC amendment could reach up to 6×10(9)copies g(-1) Volatile Suspended Solids, around 22.5 times and 12.3 times greater than that in CK and SP reactor, respectively. BC addition could accelerate the start-up of Anammox and significantly increase the Anammox bacteria number.

[Expression and significance of beta(2)-adrenoreceptor in inflammatory cells of patients with chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the relationship between beta(2)-adrenoceptor (beta(2)-AR) expression in inflammatory cells and airflow limitation in patients with chronic obstructive pulmonary disease (COPD). METHODS: According to the severity of COPD, 37 patients with stable COPD were divided into three groups. Samples of peripheral blood and induced sputum were collected from 37 COPD patients, 11 of II grade, 12 of grade III, and 14 of grade IV. Counting and classification of white blood cells in the peripheral blood and induced sputum were made. Radioligand binding assay was used to detect the maximum binding capacity (Bmax) reflecting the density, and balance dissociation constant (Kd) reflecting the affinity of beta(2)-AR in the peripheral blood mononuclear cells (PBMC) from both kinds of specimens. Thirteen normal smokers were used as control group. RESULTS: No significant differences were found in peripheral blood leukocyte count, classification and induced sputum cell count among the 3 COPD groups and control group, but the neutrophil cell count levels of induced sputum of the COPD groups were all significantly higher than that of the control group (all P = 0.00). For the control, and COPD grade II, III, and IV groups, the Bmax levels of PBMC beta(2)-AR were (106 +/- 52), (156 +/- 72), (135 +/- 57) and (123 +/- 58) fmol/mg respectively (F = 1.45, P = 0.24); the Kd levels of PBMC beta(2)-AR were (548 +/- 267), (343 +/- 144), (297 +/- 150), and (375 +/- 95) pmol/L respectively (F = 4.84, P = 0.01); the Bmax levels of beta(2)-AR of induced sputum cells were (126 +/- 46), (116 +/- 54), (106 +/- 36), and (76 +/- 30) respectively (F = 3.46, P = 0.02); and the Kd levels of beta(2)-AR of induced sputum cells were (570 +/- 290), (405 +/- 197), (404 +/- 139), and (347 +/- 123) respectively (F = 2.97, P = 0.04). There was a positive correlation between the forced expiratory volume in one second in percentage of predicted and density of beta(2)-AR in induced sputum cells from the COPD patients (r = 0.43, P = 0.01). There was a positive correlation between the Bmax of beta(2)-AR in PBMC and induced sputum cells (r = 0.40, P = 0.02). CONCLUSIONS: The expression of beta(2)-AR in PBMC and induced sputum cells from COPD patients is down-regulated with progression of the disease. The expression of beta(2)-AR in the induced sputum cells changes more significantly than that in the PBMC. The expression of beta(2)-AR in inflammatory cells in the airway may play a more important role in the COPD progress.

[A comparative study on dual-magnetic circuit beads and scattering nephelometry coagulometers in coagulational evaluation of blood-contact medical devices].

Dual-magnetic circuit beads and scattering nephelometry dual channel semiautomatic coagulometers are used for the coagulational evaluation of the 5 blood contact medical devices which consist of metals and polymers. The partial thromboplastin time(PTT) and prothrombin time(PT) tests are made based on the GB/T 16886.4-2003 standard. The results indicate that the coefficient of variation in the two groups is in the identical order of magnitude. In the PTT tests, they give the similar evaluational results. With the smaller numerical values of the PT tests, the different coagulometers give the high consilience results. So, both of dual-magnetic circuit beads and scattering nephelometry coagulometers are acceptable in the medical devices' coagulational evaluations. But the interpretation and analysis of the results of the small numerical value tests, PT tests for example, should be noticed.

[The efficacy and safety of long term home noninvasive positive pressure ventilation in patients with stable severe chronic obstructive pulmonary disease].

OBJECTIVE: To evaluate the long term efficacy and safety of long term home noninvasive positive pressure ventilation (HNPPV) in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD). METHODS: Forty patients with stable severe COPD [arterial PaCO2>or=55 mm Hg (1 mm Hg=0.133 kPa)] after hospital discharge were divided into 2 groups: the HNPPV group (n=20) with conventional therapy and HNPPV, and the control group (n=20) with conventional therapy only. Parameters before and after 2 year follow-up observation were compared, which included dyspnea grade, scale for accessory muscle use, scoring for emotional disorders, lung function test, arterial blood gases, 6-min walking distance (6MWD), mean pulmonary arterial pressure (mPAP) by electrocardiography, mortality and hospitalization rates. RESULTS: The age, gender, height, weight, dyspnea grade, scale for accessory muscle use, anxiety scores, depression scores, 6MWD, mPAP, arterial PaCO2 and PaO2, FVC, FEV1, and hospitalization rates of the 2 groups on admission were similar (t values were 1.08, 1.15, 1.20, 1.09, 0.86, 0.54, 0.00, 0.00, 0.43, 0.96, 0.76, 0.38, 0.26, 0.24 and 0.87 respectively, all P>0.05). The mortality was reduced slightly by HNPPV but with no statistically significant difference (3/20 and 8/20, respectively, chi2=3.27, P>0.05). After 2 years, the difference of the dyspnea grade, scale for accessory muscle use, anxiety scores, depression scores, arterial PaCO2 and PaO2, 6MWD, mean pulmonary artery pressure, and hospitalization rates in the HNPPV group [2.4+/-0.5, 2.6+/-0.6, 6.9+/-2.1, 6.1+/-1.6, (49.5+/-2.2) mm Hg, (60.8+/-4.7) mm Hg, (213+/-45) m, (30.3+/-2.2) mm Hg, (1.4+/-0.4) times/year] was statistically significant compared to the control group [3.9+/-0.3, 4.8+/-0.4, 11.2+/-2.6, 11.6+/-2.1, (61.5+/-2.3) mm Hg, (52.8+/-2.4) mm Hg, (127+/-23) m, (36.4+/-2.3) mm Hg, (3.9+/-0.3) times/year] (t values were 9.53, 10.83, 4.92, 7.83, 14.07, 5.41, 6.07, 4.81 and 10.22 respectively, all P<0.01). CONCLUSION: Long-term use of home noninvasive positive ventilation in patients with stable severe COPD is effective and safe.