Phase separation is regulated by post-translational modifications and participates in the developments of human diseases.

Liquid-liquid phase separation (LLPS) of intracellular proteins has emerged as a hot research topic in recent years. Membrane-less and liquid-like condensates provide dense spaces that ensure cells to high efficiently regulate genes transcription and rapidly respond to burst changes from the environment. The fomation and activity of LLPS are not only modulated by the cytosol conditions including but not limited to salt concentration and temperture. Interestingly, recent studies have shown that phase separation is also regulated by various post-translational modifications (PTMs) through modulating proteins multivalency, such as solubility and charge interactions. The regulation mechanism is crucial for normal functioning of cells, as aberrant protein aggregates are often closely related with the occurrence and development of human diseases including cancer and nurodegenerative diseases. Therefore, studying phase separation in the perspective of protein PTMs has long-term significance for human health. In this review, we summarized the properties and cellular physiological functions of LLPS, particularly its relationships with PTMs in human diseases according to recent researches.

Molecular and cellular regulation of thermogenic fat.

Thermogenic fat, consisting of brown and beige adipocytes, dissipates energy in the form of heat, in contrast to the characteristics of white adipocytes that store energy. Increasing energy expenditure by activating brown adipocytes or inducing beige adipocytes is a potential therapeutic strategy for treating obesity and type 2 diabetes. Thus, a better understanding of the underlying mechanisms of thermogenesis provides novel therapeutic interventions for metabolic diseases. In this review, we summarize the recent advances in the molecular regulation of thermogenesis, focusing on transcription factors, epigenetic regulators, metabolites, and non-coding RNAs. We further discuss the intercellular and inter-organ crosstalk that regulate thermogenesis, considering the heterogeneity and complex tissue microenvironment of thermogenic fat.

Effects of mushroom-tobacco rotation on microbial community structure in continuous cropping tobacco soil.

AIMS: Rotation is an effective strategy for controlling crop diseases and improving plant health. However, the effect of a mushroom-tobacco rotation on the composition and structure of microbial communities in continuous cropping soil is unclear. METHODS AND RESULTS: This study analysed the structure and function of soil bacterial and fungal communities using Illumina MiSeq high-throughput 16S rRNA gene sequencing. The results showed that the physicochemical properties (organic matter, available nitrogen, available phosphorus, and available potassium) and enzymatic activity (phosphatase, catalase, urease and invertase activity) in the rotation treatments (Y1, M1, Y2 and M2) were significantly higher than those in the control (continuous cropping) treatment (CK) and reached peak values in the M2 treatment. PCA showed that the soil microbial community structure in each rotation treatment was different from that in the control. The dominant bacterial phyla of the different soil treatments were Proteobacteria and Actinobacteriota, and the dominant fungal phyla of the different soil treatments were Ascomycota and Basidiomycota. The M2 rotation significantly reduced the relative abundance of harmful fungi (Penicillium and Gibberella) compared to the other treatments. RDA showed that the most abundant bacterial taxa were negatively correlated with pH and positively correlated with physicochemical properties. However, the most abundant fungal taxa were positively correlated with pH and negatively correlated with physicochemical properties. CONCLUSIONS: The mushroom-tobacco rotation can effectively maintain the ecological balance of the substrate microbial environment, and provide a more effective way to prevent the continuous cropping of tobacco.

Construction of Mental Health Knowledge Service Model Based on Online Medical Community.

This paper discusses a common mental disorder prevention mode to improve residents' mental health quality and achieve the "comprehensive and fine-grained" mental health education knowledge service. The construction of mental health knowledge service model is conducive to accurately grasp the group cognition and psychological changes and take the initiative to make decisions. This paper analyzes the needs of mental health education knowledge service system and combs the research status of applying information technology and artificial intelligence to mental health education at home and abroad, the resource data of five major online medical communities at home and abroad were screened and mined, and the mental health feature tags of college students were extracted. Based on the existing mental health diagnosis experience database and multisource text, reuse and optimize ontology integration method to systematically construct mental health education ontology. Taking mental illness as an example, the rule base is constructed and the personalized recommendation service of mental health is realized. The service model can infer and output all kinds of diagnosis and treatment knowledge to provide users with intelligent mental health education knowledge services.

Differential Effects of Natural Grazing and Feedlot Feeding on Yak Fecal Microbiota.

Variation in food and diet shapes the diversity of the gut microbiota of ruminants. The present study investigated the microbial diversity in the fecal microbiota of yaks reared under natural grazing and feedlot system. A total of 48 domestic yaks with an average age of 7.5 years were selected from two different grazing habitats: one group grazed on natural pasture (grazing yaks-GY) while the other group was fed fodder and concentrate (feedlot yaks-FY). Crude protein, non-fiber carbohydrate, hemicelluloses, and digestible dry matter contents of natural pastures were higher than those in the feedlot. The lower insoluble fiber contents were found in grazing land. The 16S rRNA gene sequencing revealed 675 and 348 unique operational taxonomic units (OTUs) in the GY and FY, respectively, in addition to 1,778 common OTUs. Overall, a total of 9,891 OTUs were identified as a whole, of which 6,160 OTUs were from GY and 3,731 were from FY. Shannon index analysis revealed a higher bacterial diversity in GY than FY. At the phylum level, Firmicutes were dominant bacterial taxa in both groups. The relative abundance of Firmicutes in GY (56% ± 0.05) was higher than in FY (41% ± 0.08). At the family level, GY had a significantly higher abundance of Ruminococcaceae (p < 0.001) and Rikenellaceae (p < 0.001) than FY, but FY had a significantly higher abundance of Prevotellaceae than GY (p < 0.001). At the genus level, abundances of Faecalibacterium, Alloprevotella, and Succinivibrio were higher in FY than in GY. This study presents novel information on fecal bacterial composition and diversity in yaks reared under two different production systems.

Genomic insights on the contribution of introgressions from Xian/Indica to the genetic improvement of Geng/Japonica rice cultivars.

Hybridization between Xian/indica (XI) and Geng/japonica (GJ) rice combined with utilization of plant ideotypes has greatly contributed to yield improvements in modern GJ rice in China over the past 50 years. To explore the genomic basis of improved yield and disease resistance in GJ rice, we conducted a large-scale genomic landscape analysis of 816 elite GJ cultivars representing multiple eras of germplasm from China. We detected consistently increasing introgressions from three XI subpopulations into GJ cultivars since the 1980s and found that the XI genome introgressions significantly increased the grain number per panicle (GN) and decreased the panicle number per plant. This contributed to the improvement of plant type during modern breeding, changing multi-tiller plants to moderate tiller plants with a large panicle size and increasing the blast resistance. Notably, we found that key gene haplotypes controlling plant architecture, yield components, and pest and disease resistance, including IPA1, SMG1, DEP3, Pib, Pi-d2, and Bph3, were introduced from XI rice by introgression. By GWAS analysis, we detected a GN-related gene Gnd5, which had been consistently introgressed from XI into GJ cultivars since the 1980s. Gnd5 is a GRAS transcription factor gene, and Gnd5 knockout mutants showed a significant reduction in GN. The estimated genetic effects of genes varied among different breeding locations, which explained the distinct introgression levels of XI gene haplotypes, including Gnd5, DEP3, etc., to these GJ breeding pedigrees. These findings reveal the genomic contributions of introgressions from XI to the trait improvements of GJ rice cultivars and provide new insights for future rice genomic breeding.

Astragalus membranaceus Alters Rumen Bacteria to Enhance Fiber Digestion, Improves Antioxidant Capacity and Immunity Indices of Small Intestinal Mucosa, and Enhances Liver Metabolites for Energy Synthesis in Tibetan Sheep.

Natural, non-toxic feed additives can potentially replace chemical medications and antibiotics that are offered sheep to improve performance. In the present study, Tibetan sheep were supplemented with the root of Astragalus membranaceus (AMT), a traditional herb used widely in China. Twenty-four male Tibetan sheep (31 ± 1.4 kg; 9-month-old) were assigned randomly to one of four levels of supplementary AMT: 0 g/kg (A0), 20 g/kg (A20), 50 g/kg (A50) and 80 g/kg (A80) dry matter intake (DMI). The A50 and A80 groups increased the diversity of rumen bacteria on d 14 and the relative abundances of fiber decomposing bacteria. Supplementary AMT upregulated the metabolism of vitamins, nucleotides, amino acids and glycan, and downregulated the metabolism of lipids and carbohydrates. In addition, supplementary AMT enriched rumen bacteria for drug resistance, and reduced bacteria incurring cell motility. In general, AMT supplementation increased the concentrations of catalase (CAT), superoxide dismutase (SOD) total antioxidant capacity (T-AOC) and secretory immunoglobulin A (sIgA) in the small intestinal mucosa and CAT and SOD in meat tissue. The liver tissue metabolome response showed that AMT in the A80 lambs compared to the A0 lambs upregulated the metabolites for energy synthesis. It was concluded that supplementary A. membranaceus increased the relative abundances of fiber decomposing bacteria and improved the antioxidant capacities and immunity indices of small intestinal mucosa and meat tissue in Tibetan sheep.

Astragalus root extract improved average daily gain, immunity, antioxidant status and ruminal microbiota of early weaned yak calves.

BACKGROUND: Early weaning in yak calves is being attempted to improve yak reproduction rate. However, this has to be done with caution because of the high mortality rate of calves due to the lack of nutrients and the harsh environmental conditions. Twenty-four weaned male yak calves were used in a 60 day feeding trial in which astragalus root extract (ARE) was supplemented. They were assigned randomly to one of four dietary treatments (n = six per treatment) that differed in ARE level: 0 g kg-1 (control), ARE0 ; 20 g kg-1 , ARE20 ; 50 g kg-1 , ARE50; and 80 g kg-1 dry matter intake (DMI), ARE80 . RESULTS: Final bodyweight and average daily gain (ADG) were significantly higher and the DMI/ADG ratio was significantly lower in calves with ARE supplementation than control (ARE0 ) calves. Ruminal concentrations of acetate and propionate and serum concentration of superoxide dismutase in ARE80 calves were higher than in the other groups and serum concentration of insulin was higher in ARE80 calves than in ARE20 calves. Serum immunoglobulin G (IgG) and interleukin-2 (IL-2) concentrations in ARE-fed calves were higher than in controls. Serum tumor necrosis factor (TNF-α) concentration was higher in ARE50 and ARE80 groups than ARE0 calves and serum interleukin-6 (IL-6) concentration was higher in ARE80 than in ARE0 calves. Serum immunoglobulin A (IgA), IgG and immunoglobulin M (IgM) concentrations increased with age in ARE-fed calves. ARE supplementation increased the abundance of fiber degrading bacteria. CONCLUSION: ARE at a dosage of 5% to 8% DMI can be supplemented to early weaned yak calves to improve growth performance, antioxidant capacity and immunity. © 2020 Society of Chemical Industry.

Construction of a high-density SNP-based genetic map and identification of fruit-related QTLs and candidate genes in peach [Prunus persica (L.) Batsch].

BACKGROUND: High-density genetic mapping is a valuable tool for mapping loci that control specific traits for perennial fruit trees. Peach is an economically important fruit tree and a model Rosaceae species for genomic and genetic research. In peach, even though many molecular markers, genetic maps and QTL mappings have been reported, further research on the improvement of marker numbers, map densities, QTL accuracy and candidate gene identification is still warranted. RESULTS: A high-density single nucleotide polymorphism (SNP)-based peach linkage map was constructed using specific locus amplified fragment sequencing (SLAF-seq). This genetic map consisted of 7998 SLAF markers, spanning 1098.79 cM with an average distance of 0.17 cM between adjacent markers. A total of 40 QTLs and 885 annotated candidate genes were detected for 10 fruit-related traits, including fruit weight (FW), fruit diameter (FD), percentage of red skin colour (PSC), eating quality (EQ), fruit flavour (FV), red in flesh (RF), red around pit (RP), adherence to pit (AP), fruit development period (FDP) and fruit fibre content (FFC). Eighteen QTLs for soluble solid content (SSC) were identified along LGs 1, 4, 5, and 6 in 2015 and 2016, and 540 genes were annotated in QTL intervals. Thirty-two QTLs for fruit acidity content (FA) were detected on LG1, and 2, 4, 5, 6, and 1232 candidate genes were identified. The expression profiles of 2 candidate genes for SSC and 4 for FA were analysed in parents and their offspring. CONCLUSIONS: We constructed a high-density genetic map in peach based on SLAF-seq, which may contribute to the identification of important agronomic trait loci. Ninety QTLs for 12 fruit-related traits were identified, most of which overlapped with previous reports, and some new QTLs were obtained. A large number of candidate genes for fruit-related traits were screened and identified. These results may improve our understanding of the genetic control of fruit quality traits and provide useful information in marker-assisted selection for fruit quality in peach breeding programmes.

[Study on effects of different habitat processing methods of Salviae Miltiorrhizae Radix et Rhizoma in rats with acute myocardial ischemia].

To investigate the effects of different habitat processing methods of Salviae Miltiorrhizae Radix et Rhizoma on acute myocardial ischemia induced by pituitrin in rats. In this experiment, the tail vein injection of pituitrin was used to induce acute myocardial ischemia in rats. Electrocardiograph(ECG) heart rate and ΔST changes were recorded, and the levels of creatine kinase isoenzyme(CK-MB), lactate dehydrogenase(LDH), superoxide dismutase(SOD) and malondialdehyde(MDA) in serum of rats were detected to comprehensively evaluate the effects of six processing methods of Salviae Miltiorrhizae Radix et Rhizoma on serum biochemical indexes of rats with acute myocardial injury. The ECG results showed that the Salviae Miltiorrhizae Radix et Rhizoma dried in a drying oven had a good effect on the improvement of heart rate and ΔST of electrocardiogram after ischemia, and all the other groups had some protective effects to different degrees. The results of biochemical indexes in serum of each group after ischemia showed that the activity of CK-MB decreased most significantly in Salviae Miltiorrhizae Radix et Rhizoma high-dose group with drying in a drying oven after sweating and losing weight in a drying oven, high-dose group with drying in the shade and low-dose group with drying in the shade. The activity of LDH decreased most significantly in Salviae Miltiorrhizae Radix et Rhizoma high-dose group with drying in the shade and low-dose group of drying in the shade. The activity of SOD increased most significantly in Salviae Miltiorrhizae Radix et Rhizoma low-dose group with drying in sun, low-dose group with drying in sun after sweating and losing weight in sun, and low-dose group with drying in a drying oven. The activity of MDA decreased most significantly in Salviae Miltiorrhizae Radix et Rhizoma low-dose group with drying in sun. The comprehensive scoring results showed that the highest score was obtained in Salviae Miltiorrhizae Radix et Rhizoma high-dose group with drying in the shade while the scores of other treatment groups were higher than that of the model group. It could be seen that the Salviae Miltiorrhizae Radix et Rhizoma dried in a drying oven had a good improvement effect on electrocardiograph indexes after acute myocardial injury, the Salviae Miltiorrhizae Radix et Rhizoma dried in the shade had a good improvement effect on serum myocardial enzymes after acute myocardial injury, and the other processing methods had a certain protective effect on myocardial injury. The six processing methods evaluated by pharmacodynamics showed that the Salviae Miltiorrhizae Radix et Rhizoma dried in the shade and dried in a drying oven had good efficacy.

Phosphorylation of TET2 by AMPK is indispensable in myogenic differentiation.

BACKGROUND: TET-mediated oxidation of 5-mC participates in both passive and active DNA demethylation, which exerts a significant influence on diverse biological processes. Mass spectrometry has identified multiple phosphorylation sites of TET2. However, the functions of these phosphosites and their corresponding kinases are mostly unknown. RESULTS: Here, we showed that AMP-activated protein kinase (AMPK) phosphorylates murine TET2 at the serine residue 97 (S97), and the phosphorylation enhances TET2 stability through promoting its binding to 14-3-3ß. AMPK ablation resulted in decreased global 5-hmC levels at the myotube stages, severe differentiation defects of C2C12 cells and significantly, total loss of expression of Pax7. Genome-wide analyses revealed increased DNA methylation at genic and enhancer regions of AMPK-null myoblasts and myotubes. Using CRISPR/Cas9 technology, we showed that a novel enhancer, which is hypermethylated in AMPK-null cells, regulates Pax7 expression. The phospho-mimicking mutant, TET2-S97E, could partly rescue the differentiation defect in AMPK-ablated C2C12 cells. CONCLUSIONS: Together, our data demonstrated that AMPK is a critical regulator of myogenesis, partly through phosphorylating TET2.

Phase Transitions in Dipalmitoylphosphatidylcholine Monolayers.

A self-assembled phospholipid monolayer at an air-water interface is a well-defined model system for studying surface thermodynamics, membrane biophysics, thin-film materials, and colloidal soft matter. Here we report a study of two-dimensional phase transitions in the dipalmitoylphosphatidylcholine (DPPC) monolayer at the air-water interface using a newly developed methodology called constrained drop surfactometry (CDS). CDS is superior to the classical Langmuir balance in its capacity for rigorous temperature control and leak-proof environments, thus making it an ideal alternative to the Langmuir balance for studying lipid polymorphism. In addition, we have developed a novel Langmuir-Blodgett (LB) transfer technique that allows the direct transfer of lipid monolayers from the droplet surface under well-controlled conditions. This LB transfer technique permits the direct visualization of phase coexistence in the DPPC monolayer. With these technological advances, we found that the two-dimensional phase behavior of the DPPC monolayer is analogous to the three-dimensional phase transition of a pure substance. This study has implications in the fundamental understanding of surface thermodynamics as well as applications such as self-assembled monolayers and pulmonary surfactant biophysics.

[Regulation of global transcriptional factor cyclic AMP receptor protein and its metabolic engineering application in Escherichia coli].

Cyclic amp receptor protein (CRP) is a global transcriptional factor in many prokaryotes, capable of governing nearly half of the total genes in Escherichia coli. Through the method of error-prone PCR or DNA shuffling, we can first obtain CRP mutant library and then get the expected cell phenotype with enhanced resistance. In this article, we reviewed the following desired phenotype: enhanced tolerance towards oxidative stress, improved osmotolerance, enhanced organic solvent (toluene) tolerance, improved acetate tolerance of E. coli fermentation and improved ethanol tolerance during bio-ethanol production. We then concluded that CRP can also be applied in other host cells to get desired phenotypes. Last, we predicted potential applications of mutant CRP transcriptional factor.

Study of the structural and the spectral characteristics of [C3N3(NH2)3]n (n = 1-4) clusters.

Previous research has shown that interactions between melamine molecules within a cluster can give rise to the molecular self-assembly and that the spectral characteristic of melamine can be used to inspect melamine in a carrier. Although the structural and spectral characteristics of an isolated single melamine molecule and the molecular arrays on metal or semiconductor surfaces have been studied extensively, little is known about that of isolated multimolecular melamine clusters. In this work, density functional theory (DFT) calculations at the ω-B97XD/6-311++G(d,p) level were performed to study the structural and spectral characteristics of isolated melamine clusters [C3N3(NH2)3]n (n = 1-4) in the ground state. The calculation shows that a ground-state single melamine molecule takes a quasi-planar structure. The C and N atoms of the molecule are in one plane, which we call the molecular plane, while the H atoms deviate slightly from the molecular plane. When melamine molecules gather to form a cluster, the intermolecular hydrogen bonds (IHBs) N-H···N will arise, with the lengths of H···N in the range from 1.960 to 1.970 Å; the length of N-H will be elongated to 1.022 Å from its original of 1.004 Å, the N-H···N bond angles will be about 176°, and the average single-bond binding energy will be approximately -0.285 eV. In a multimolecular cluster, each melamine molecule still takes the quasi-planar structure. Each molecular plane in the cluster retains a planar structure, and some H atoms diverge more from their molecular planes. The molecular planes in a cluster are not coplanar, and the dihedral angle between the molecular planes of two neighboring melamine molecules ranges from 38 to 40°. In addition, the theoretical study of the infrared (IR) spectrum and nuclear magnetic resonance (NMR) spectrum of [C3N3(NH2)3]n (n = 1-4) was conducted. The results confirm the existence of IHBs in a multimolecular melamine cluster and reveal the symmetry of the electron cloud distribution in the melamine clusters. Experimental study of the IR for solid-state melamine and (13)C NMR spectra for both solid- and liquid-state melamine samples were also carried out, in which the corresponding spectral characteristics of [C3N3(NH2)3]n (n = 2-4) clusters deduced from theoretical study were observed. Findings of this study may serve as theoretical references for future identification and utilization of melamine clusters.

Seed priming with chitosan improves maize germination and seedling growth in relation to physiological changes under low temperature stress.

Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 degrees C on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60 approximately 64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress.

Relationships between changes of kernel nutritive components and seed vigor during development stages of F1 seeds of sh2 sweet corn.

The changes of kernel nutritive components and seed vigor in F1 seeds of sh2 sweet corn during seed development stage were investigated and the relationships between them were analyzed by time series regression (TSR) analysis. The results show that total soluble sugar and reducing sugar contents gradually declined, while starch and soluble protein contents increased throughout the seed development stages. Germination percentage, energy of germination, germination index and vigor index gradually increased along with seed development and reached the highest levels at 38 d after pollination (DAP). The TSR showed that, during 14 to 42 DAP, total soluble sugar content was independent of the vigor parameters determined in present experiment, while the reducing sugar content had a significant effect on seed vigor. TSR equations between seed reducing sugar and seed vigor were also developed. There were negative correlations between the seed reducing sugar content and the germination percentage, energy of germination, germination index and vigor index, respectively. It is suggested that the seed germination, energy of germination, germination index and vigor index could be predicted by the content of reducing sugar in sweet corn seeds during seed development stages.

Evaluation on dispersion behavior of the aqueous copper nano-suspensions.

This paper presents a procedure for preparing a nanofluid which is solid-liquid composite material consisting of solid nanoparticles with sizes typically of 1-100 nm suspended in liquid. By means of the procedure, Cu-H(2)O nanofluids with and without dispersant were prepared, whose sediment photographs and particle size distribution were given to illustrate the stability and evenness of suspension with dispersant. Aiming at the dispersion of nano-Cu is regarded as the guide of heat transfer enhancement, the dispersion behavior of Cu nanoparticles in water were studied under different pH values, different dispersant types and concentration by the method of zeta potential, absorbency and sedimentation photographs. The results show that zeta potential has good corresponding relation with absorbency, and the higher absolute value of zeta potential and the absorbency are, the better dispersion and stability in system is. The absolute value of zeta potential and the absorbency are higher at pH 9.5. Hexadecyl trimethyl ammonium bromide (CTAB) [corrected] and sodium dodecylbenzenesulfonate (SDBS) can significantly increase the absolute value of zeta potential of particle surfaces by electrostatic repulsions, and polyoxyethylene (10) nonyl phenyl ether (TX-10) can form a thick hydration layer on the particle surfaces by steric interference, which leads to the enhancement of the stability for Cu suspensions. In the 0.1% copper nano-suspensions, the optimizing concentrations for TX-10, CTAB [corrected] and SDBS are 0.43, 0.05, and 0.07%, respectively, which have the best dispersion results.

Simulation study of second-harmonic microscopic imaging signals through tissue-like turbid media.

We establish, for the first time, a simulation model for dealing with the second-harmonic signals under a microscope through a tissue-like turbid medium, based on the Monte Carlo method. With this model, the angle-resolved distribution and the signal level eta of second-harmonic light through a slab of the turbid medium are demonstrated and the effects of the thickness (d) of the turbid medium, the numerical aperture (NA) of the objective as well as the size (rho) of the scatterers forming the turbid medium are explored. Simulation results reveal that the use of a small objective NA results in a narrow angle distribution but strong second-harmonic signals. A turbid medium consisting of large scattering particles has a strong influence on the angle distribution and the signal level eta, which results in a low penetration limit for second-harmonic signals made up of ballistic photons. It is approximately 30 microm in our situation.

Efficiency and current in a correlated ratchet.

We present a detailed study of the transport and the efficiency of a ratchet system in a periodic potential in the presence of correlated noises. The current and the efficiency of the system are investigated. It is found that, when the potential is spatially symmetric, the correlation between the two noises can induce a net transport. The efficiency shows many interesting features as a function of the applied force, the noise intensity, the external load, etc. The efficiency can be maximized as a function of noise intensity (or temperature), which shows that the thermal fluctuation can facilitate the efficiency of energy transformation.

Correlated noise in a logistic growth model.

The logistic differential equation is used to analyze cancer cell population, in the presence of a correlated Gaussian white noise. We study the steady state properties of tumor cell growth and discuss the effects of the correlated noise. It is found that the degree of correlation of the noise can cause tumor cell extinction.