Fractal Dimension Df Research Articles

Properties of nano protein particle in solutions of myofibrillar protein extracted from giant squid (Dosidicusgigas).

This work studied the quantitation of myofibrillar protein isolated from giant squid by three methods (Bradford, biuret, and direct ultraviolet absorbance). The results were examined in relation to compositional size exclusion chromatography, static light scattering, zeta-potential and thermal analysis; comparisons between the apparent vs. the true protein concentration revealed the existence of disk-like nano protein particles (NPP) with a height of 2-3nm, diameters ranging from several tens nm to 140nm, and fractal dimensions df of less than 1.3. In order to probe the heterogeneity of NPP particles, their properties were studied under consecutive dilutions: the df decreased from 1.265 to 1.087, the zeta-potential increased from -4.55mV to -1.83mV, the denaturation temperature reduced from 63.9°C to 58.6°C, and the endothermic enthalpy reduced from 0.529Js-1 to 0.362Js-1. In addition, ca. 90% protein molecules in solution were aggregated to form NPP.

Cell Theranostics on Mesoporous Silicon Substrates.

The adhesion, proliferation, and migration of cells over nanomaterials is regulated by a cascade of biochemical signals that originate at the interface of a cell with a substrate and propagate through the cytoplasm to the nucleus. The topography of the substrate plays a major role in this process. Cell adhesion molecules (CAMs) have a characteristic size of some nanometers and a range of action of some tens of nanometers. Controlling details of a surface at the nanoscale—the same dimensional over which CAMs operate—offers ways to govern the behavior of cells and create organoids or tissues with heretofore unattainable precision. Here, using electrochemical procedures, we generated mesoporous silicon surfaces with different values of pore size (PS ≈ 11 nm and PS ≈ 21 nm), roughness (Ra ≈ 7 nm and Ra ≈ 13 nm), and fractal dimension (Df ≈ 2.48 and Df ≈ 2.15). Using electroless deposition, we deposited over these substrates thin layers of gold nanoparticles. Resulting devices feature (i) nanoscale details for the stimulation and control of cell assembly, (ii) arrays of pores for drug loading/release, (iii) layers of nanostructured gold for the enhancement of the electromagnetic signal in Raman spectroscopy (SERS). We then used these devices as cell culturing substrates. Upon loading with the anti-tumor drug PtCl (O,O′-acac)(DMSO) we examined the rate of adhesion and growth of breast cancer MCF-7 cells under the coincidental effects of surface geometry and drug release. Using confocal imaging and SERS spectroscopy we determined the relative importance of nano-topography and delivery of therapeutics on cell growth—and how an unbalance between these competing agents can accelerate the development of tumor cells.

Modulation of angiogenesis by topical application of leptin and high and low molecular heparin using the Japanese quail chorioallantoic membrane model.

Pathological angiogenesis characterized by uncontrollable vessel growth is an accompanying feature of many diseases. The avian embryo chorioallantoic membrane (CAM) is an excellent model for angiogenesis research. In our study we used a less common Japanese quail CAM model for the testing of angiogenic potential of leptin, high-molecular (heparin sodium) andlow-molecular (nadroparin calcium) heparins. Heparins play a significant role in vascular endothelial cell function, and they are able to modulate the activities of angiogenic growth factors. On embryonic day 7 leptin (5 μg per CAM), heparin sodium (75 IU per CAM) and nadroparin calcium (47.5 IU per CAM) in 500 μl PBS were applied on the CAM surface. After 24 h the fractal dimension (Df) of the vasculature was evaluated. Samples from each group were histologically analyzed and VEGF-A and Quek1 expression were detected by qPCR. Df was significantly increased in the leptin group. A moderate stimulatory effect of heparin sodium and an inhibitory effect of nadroparin calcium were observed. Both leptin and heparin sodium caused a noticeable increase in the CAM thickness compared to the control and nadroparin calcium groups. We observed an increased number of blood vessels and accumulation of fibroblasts. There was no significant impact on gene expression of VEGF-A and Quek1 24 h after treatment, however, trends similar to the changes in Df and CAM thickness were present. The resulting effect of nadroparin administration on Quek1 levels was exactly the opposite to that of leptin (p < 0.05).

Simultaneous evaluation of bioactivity and settleability of activated sludge using fractal dimension as an intermediate variable

Bioactivity and settleability of activated sludge are essential for the operation of activated sludge systems in wastewater treatment. In this work, the fractal dimension of sludge image is proposed as a tool to evaluate these two factors. The specific endogenous respiration rate (SOURe) and the specific quasi-endogenous respiration rate (SOURq) are found to be more dependent on the 3D structure of sludge than the specific total respiration rate (SOURt). The relationship between the fractal structure and bioactivity suggests that the bioactivity governs the acceptable upper bound of the fractal dimension (Df), as at its theoretical maximum of 2.0, the non-porous compact flocs are predominant. The settleability or the biomass concentration determines the acceptable lower bound of Df, as at its theoretical minimum of 1.0, the free-swimming microbes are predominant. Our data reveal that the activated sludge has an acceptable fractal dimension Df in a range of 1.07–1.68. In practice, the fractal dimension should be controlled at a reasonable value as there is a trade-off between the bioactivity and physical structure to achieve better performance. A decrease or increase in the fractal dimension can serve as a signal for the change of the operational status, and this is further elucidated from the perspective of settling tanks using state point analysis. Compared with respirogram measurement, measuring fractal dimension is a complex process and its online implementation is challenging. Also, the measured value varies with the methods used. In addition, the difference in their theoretical values depends on the homogeneity of the sludge structure. Since the fractal dimension Df reflects both bioactivity and settleability of the sludge but is difficult to measure, in this work a relationship between Df and the easily measurable respirogram is established, and a method using the respirogram as a proxy of Df is proposed to control the bioactivity and settleability simultaneously. This respiration-based method is able to simultaneously control aeration and settling tanks, and could serve as an efficient tool for the management of wastewater treatment plants.

Revealing the variations in physicochemical, morphological, fractal, and rheological properties of digestate during the mesophilic anaerobic digestion of iron-rich waste activated sludge

Dosing of iron (Fe)-salts in sewers to control odour and corrosion problems have proven to be effective on phosphate and sulfide removal in downstream treatment units. However, the interaction of Fe with sludge may impact the sludge properties during wastewater treatment and sludge digestion. Herein, we investigated the downstream impacts of sewer-dosed Fe-salt on key digestate properties including digestate dewaterability. For this, Fe-salt was dosed to a sewer reactor and resultant iron-rich waste activated sludge (Fe-WAS) was digested in an anaerobic digester (AD) in the experimental line of integrated laboratory system running in parallel to a control system. Iron containing and non-iron containing digestates were sourced from the respective AD reactors of experimental and control lines. Results showed improved dewaterability in iron containing digestate than non-iron containing digestate, which was attributed to the variations in key digestate properties. Compared to non-iron containing digestate, iron containing digestate exhibited the decreased contents of bound water, soluble extracellular polymeric substances (S-EPS), protein, polysaccharide, and monovalent-to-divalent (M+/D++) cations ratio. Likewise, we observed the increased mean particle size (Dv50) for iron containing digestate than the non-iron containing digestate, but fractal dimension (Df) values were comparable. Besides, iron containing digestate exhibited a reduced degree of thixotropy, relative sludge network strength, viscosity, yield stress, flow stress, and storage/loss/complex (G′/G′′/G∗) moduli but increased creep compliance and shear strain (%) than non-iron containing digestate. The combined synergistic effects of such favorable changes amongst the key properties of iron containing digestate, might have been responsible for improving it’s dewaterability.

In vitro clot model to evaluate fibrin-thrombin effects on fractal dimension of incipient blood clot.

This aim of this study is to investigate the individual effects of varying concentrations of thrombin and fibrinogen on clot microstructure (characterised through the fractal dimension of the incipient clot network, df) and clot formation time (TGP) using a fibrin-thrombin clot model. df and TGP markers are measured using a haemorheological method that has already been investigated for whole blood. This is an in vitro study using three thrombin concentrations (0.1, 0.05 and 0.02 NIH/ml) and two fibrinogen concentrations (8 mg/ml and 12 mg/ml) to investigate a fibrin-thrombin clot model. The haemorheological changes were measured at the gel point using df and TGP. Fractal dimension (df) increased with increasing concentrations of thrombin both at 8 mg/ml (1.60±0.024, 1.67±0.022, 1.74±0.079) and 12 mg/ml fibrinogen concentrations (1.63±0.02, 1.87±0.019, 1.95±0.014). On the other hand, TGP decreased for both 8 mg/ml (1089±265, 637±80, 223±22 seconds) and 12 mg/ml fibrinogen concentrations (2008±247, 776±20, 410±20 seconds). In contrast to previous studies investigating whole blood, TGP increased with higher fibrinogen levels. The findings from this fibrin-thrombin clot model confirmed that df and TGP can detect changes in the incipient clot following manipulation of fibrinogen and thrombin concentration. df increases (indicating stronger clot) with higher concentrations of thrombin and fibrinogen. On the other hand, TGP decreased as expected with higher thrombin level but not with higher fibrinogen concentrations.

Self-Similar Polymer Ring Conformations Based on Elementary Loops: A Direct Observation by SANS

We report small angle neutron scattering (SANS) results on very large polyethylene-oxide (PEO) rings in the melt. Major findings are (i) the observation of a cross over in the SANS pattern from a strong Q-dependence at intermediate Q to a Q-2 dependence at higher Q that is independent of the ring size. Summing up scattering amplitudes in a minimal model that contains the ring closure and a cross over from Gaussian statistics at short distances to more compact structures at larger distances, we identify the cross over to occur at a distance along the ring of Ne,0 = 45 ± 2.5. We consider this finding as a clear signature of the theoretically predicted elementary loops that build up the ring conformation. Their size is in the range of an entanglement strand for linear PEO melts and they are characterized by Gaussian statistics. (ii) The chain length dependence of the radius of gyration Rg follows rather closely the prediction of Obukhov's decorated ring model. (iii) Other than extracted from numerous simulations that are interpreted in terms of a cross over to mass fractal behavior around N ≅ 10Ne,0 with a fractal dimension df = 3 and exponent ν = 1/3, we do not observe such a cross over, but Rg(N) ∼ Nν=0.39 holds over the entire size range.

Effects of ethanol on gelation of iota-carrageenan

The gelation of iota carrageenan (IC) with different ethanol concentrations (0–40 mL/100 mL) was investigated in terms of rheology, chemical structure, and microstructure. Ethanol facilitated IC gel formation with predictable increasing gelling temperature (52.6–62.6 °C) and critical gelling points (50.8–61.3 °C). The ethanol –OH moiety was responsible for Kirkwood-Buff theory through exclusion effects and direct binding with IC. Fourier transform infrared (FTIR) confirmed the binding with the chemical shifts on both sulphated groups (G4S from 850 to 854 cm−1 and DA2S from 805 to 808 cm−1). The gel strength decreased at < 10 mL/100 mL ethanol and increased up to 40 mL/100 mL ethanol. From Winter-Chambon equation, 40 mL/100 mL ethanol provided a significantly lower fractal dimension df (2.09). Confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM) also showed a less complex network. These results indicated that a small amount of ethanol stabilised IC gelation and that the increased gel strength was more significant at high ethanol concentrations (>10 mL/100 mL), which improved the design of IC-ethanol systems.

Morphology of soot sampled from N2-diluted methane/air counterflow flames at elevated pressures via TEM imaging

An experimental work is carried out to investigate the influence of pressure on morphological parameters of soot in counterflow flames of N2-diluted methane and air. Flames are stabilized at 3, 5, 7 and 10 atm in a pressure vessel and a global strain rate of 30 s−1 is maintained at all pressures by adjusting the inlet mass flux. The mole fraction of methane is maintained at 0.7. The entire soot zone of the counterflow flames are sampled using a thermophoretic sampling device attached to the pressure vessel. Our sampling method minimizes the flow disturbances to a level that they are visually negligible during the sampling process. Collected samples are analyzed under a transmission electron microscope and information about mean primary particle diameter, fractal dimension (Df), fractal prefactor (kf) and aggregate size distribution is inferred at different pressures. To investigate the effects of carbon flux on primary particle size, fuel mole fraction is decreased to 0.5 and primary particle size is investigated at 5, 7 and 10 atm. Mean primary particle size increases by 70% when pressure is changed from 5 to 10 atm and remains independent of fuel mole fractions. Geometric mean and geometric width of aggregate size distributions also increase by increasing the pressure. Fractal properties of soot aggregates are found to be insensitive to the pressure. Fractal dimension varies between 1.56 and 1.65 while fractal prefactor values range between 1.96 and 2.1.

Fractal analysis of the formation process and morphologies of hyaluronan/chitosan nanofilms in layer-by-layer assembly

In the last decade, hyaluronan (HA, polyanion) and chitosan (CHI, polycation) biopolymers have been assembled by layer-by-layer (LbL) for the synthesis of antibacterial coatings. As electrostatic interactions are the main driving force for the formation of LbL films, pH and ionic strength (IS) are important critical variables of synthesis. In this context, we used surface fractal analysis of HA/CHI films to characterize the growth process for different bilayers obtained with two pH (5 and 3) and IS values (0 and 0.1 M NaCl). Our results showed that the HA/CHI assembling is mainly affected by changes in the pH than IS. Fractal dimension (Df) of pH 5 series presented values ~2.2, indicating that irregularities from the initial random adsorption process are minimized. However, when pH decreased to 3, Df increases up to ~2.5, suggesting a transition to diffusion-limited aggregation.

Soundproofing performance of flexible polyurethane foams as a fractal object

Noise pollution is one of the most severe environmental concerns due to its damaging effects on human health. This study aimed to evaluate the relationship between the acoustic damping behavior and fractal dimension (Df) of flexible polyurethane foams (FPUFs) manufactured by different synthesized linear saturated aliphatic polyesters (LSAP) resins, methylene diphenyl diisocyanate (MDI), etc. (isocyanate index = 110 & water content = 5%). Cellular and soundproofing properties of FPUFs were evaluated by an optical microscope and impedance tube device. Df was calculated by the box-counting method after binarization and image processing of FPUF images. Results indicate that by increasing Df from 1.5415 to 1.8554, the total sound absorption performance (S) of FPUFs improves by 43.07% and the maximum sound absorption coefficient reaches 0.98. The relation between S and Df was obtained as follows: Log(S) = 0.4583 Df + 2.6659, r2 = 0.9298. Generally, decreasing the cell size and increasing the cell size distribution and open-cell content, increase Df and irregularity of FPUFs. The results reveal that FPUFs with an optimum condition of cell size of 180–200 μm, open-cell content of 30%, and density of 110 (Kg.m−3) have the highest Df and can be a promising candidate as sound insulating materials.

Viscoelastic behavior of high molecular weight polyimide/cyclohexanone solution during sol-gel transition

It is very important to optimize rheological properties of polyimide (PI) solution for film casting or fiber spinning. Herein, a soluble 2,2-bis(3,4-di-carboxyphenyl) hexafluoro propane dianhydride-2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl PI sample with high absolute molecular weight of 390,000 g/mol was obtained by precipitation fractionation. The viscoelastic behavior of PI in cyclohexanone solution was investigated at different concentrations (0.1–12 wt%). PI gel can form at a suitable concentration. Analysis of viscoelastic storage and loss moduli, G' and G'', based on the Winter and Chambon model gives the gel concentration cg = 4 wt% and the critical relaxation exponent n = 0.56. The scaling relations such as zero-shear viscosity η0 and equilibrium modulus Ge against relative distance from the gel point ε, that is η0∝ε−γ and Ge∝εz, were examined in the vicinity of cg, where a fractal dimension df = 2.54 indicates formation of a compact gel structure. Addition of N,N-dimethylformamide (DMF) strongly decrosslinks the PI solution, suggesting a screening of the interchain dipole–dipole interactions by the highly polar DMF solvent.

Fractal geometry of the fatigue fracture surface of the ZTA composites

A fracture surface of the ceramic composite Al2O3 - ZrO2 at three-point bending during fatigue loading has been studied by scanning electron microscope. The bending strength and flexural modulus are derived under static conditions at a loading rate of 3 mm/min. The fatigue strength and fatigue limit are investigated at a frequency of 4 Hz in three stress ranges: 0.9, 0.8 and 0.7 of the average maximum static bending strengths. The surface fractal dimensions Df is determined using triangulation method. It was shown that the surface relief can be characterized by fractal relief in the local approximation. The fractal dimensionality of the studied surface changes in the relatively narrow limits Df = 2.653 - 2.742, for ceramic samples sintered at 1650 °C, and highly dependent on the number of cycles. The ceramic samples sintered at 1400 °C showed low resistance to fatigue loads with the fractal dimensionality Df = 2.710 - 2.781, which are independent of the number of cycles.

Fractal dimension and phase transition of graphene oxide (GO) doped polyacrylamide

Graphene Oxide (GO)- Polyacrylamide composites prepared between 5 and 50 μl GO were performed by Fluorescence Spectroscopy. The phase transition performed on the composites was measured by calculating the critical exponents, β and γ, respectively. In addition, fractal analysis of the composites was calculated by a fluorescence intensity of 427 nm. The geometrical distribution of GO in the composites was calculated based on the power law exponent values using scaling models. While the gelation proceeded GO plates first organized themselves into a 3D percolation cluster with the fractal dimension (Df) of the composite, Df = 2.63, then After it goes to diffusion limited clusters with Df = 1.4, its dimension lines up to a Von Koch curve with a random interval of Df = 1.14.

Effect of tillage and maize-cowpea intercrop on fractal features of particle and aggregate size distribution on a tropical sandy loam soil in southwest Nigeria

The effects of tillage and cropping pattern on soil aggregation, fractal dimensions and distribution of organic carbon fractions were studied. Treatments were notillage (NT), conventional tillage (CT), and four cropping patterns viz: sole maize, sole cowpea, maize-cowpea intercrops and control (no crop). Soil samples were analysed for particle size distribution (PSD); aggregation ratio (AR), meanweight diameter (MWD) and aggregated silt+clay (ASC). Mass fractal dimension (Dm) was obtained from PSD; while fragmentation fractal dimension (Df) was obtained from aggregate sizes. Total organic carbon (TOC), free and occluded particulate organic carbon (fPOC and oPOC), were measured. Results showed that structural stability at micro-aggregate scale measured by aggregated silt + clay (ASC) was significantly (p &lt; 0.05) highest for NT (4.07) than CT (1.58). The CT significantly (P ≤ 0.05) reduced the larger aggregate fraction (5.66-2.00 mm). The difference in fractal dimensions was significantly higher with NT than control with CT. Lower difference between Dm and Df with CT represents higher degree of fragmentation of aggregates. Correlation showed significant positive linear relationships between Dm and sand (p &lt; 0.05, r = 0.627) and negative relationship with silt and clay (r = -0.675). Therefore, fractal dimensions derived from aggregates sizes rather than particle size distribution reflected the impact of land management practices on fragmentation of aggregates of most tropical soils.

Study of self-organized structure in carbon nanotube forest by fractal dimension and lacunarity analysis

In this work, a fractal analysis of a morphology of carbon nanotube (CNT) forest was conducted. A self-similarity between the formation of catalyst nanoparticles, low and high-density CNT forest growth, and Raman mapping was investigated, for a catalyst thickness of 0.8, 1.0, and 1.2 nm. To explain reasons behind fluctuations of the CNT forest structure, a fractal dimension (Df) and lacunarity (Λ) were calculated, using a box-counting method. During the fractality analysis of catalyst particles, the highest Df was obtained for the 0.8-nm-thick film (Df = 1.91), while the lowest one was noted for the Fe catalyst thickness of 1.2 nm (Df = 1.72). The progressive increase of the catalyst thickness affected the dewetting, Ostwald ripening and diffusion processes, affecting the catalyst size distribution and arrangement. The same thickness variation led to a similar decreasing trend of Df changes, which was observed in the planar and linear analysis of the distribution of CNTs and in the IG/ID ratio distribution in Raman mapping, confirming the complexity and the self-organizing properties of CNT forest. The self-similarity and scaling of properties of self-organized CNT forest structure were proved by the analysis of fractal dimension and lacunarity analysis and revealed different stages of the catalyst annealing.

Synthesis of the Hydrophobic Cationic Polyacrylamide (PADD) Initiated by Ultrasonic and its Flocculation and Treatment of Coal Mine Wastewater

In this study, a new type of hydrophobic cationic polyacrylamide P (AM-DMC-DABC) (PADD) was synthesized by ultrasonic (US)-initiated polymerization, which is used for the separation and removal of coal mine wastewater. The acrylamide (AM), methacryloyloxyethyl trimethyl ammonium chloride (DMC) and acryloyloxyethyl dimethylbenzyl ammonium chloride (DABC) were used as monomers to prepare). The factors that affecting the US initiated polymerization of PADD were analyzed. Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR) and scanning electron microscopy (SEM) were used to characterize the chemical structure, thermal decomposition performance and surface morphology of the polymers. FT-IR and 1H NMR results showed that PADD was successfully synthesized. In addition, irregular porous surface morphology of PADD were observed by SEM analysis. Under the optimum conditions (pH = 7.0, flocculant dosage = 16.0 mg/L), the excellent flocculation performance (turbidity removal rate (TR) = 98.8%), floc size d50 = 513.467 μm, fractal dimension (Df) = 1.61, flocculation kinetics (KN0) = 27.24 × 10−3·s−1) was obtained by using high-efficiency flocculant PADD. Zeta potential analysis was used to further explore the possible flocculation mechanism of removal. The zeta potential and flocculation analytical results displayed that the flocculation removal process of coal mine wastewater mainly included hydrophobic effect, adsorption, bridging and charge neutralization, and electric patching when PADD was used. The PADD showed more excellent coal mine wastewater flocculation performance than PAD, commercial cationic polyacrylamide (CPAM) CCPAM and PAM. Thus PADD, with its good flocculation effect on coal mine wastewater under relatively wide pH range, had bright practical application value.

Effect of tillage and maize-cowpea intercrop on fractal features of particle and aggregate size distribution on a tropical sandy loam soil in southwest Nigeria

The effects of tillage and cropping pattern on soil aggregation, fractal dimensions and distribution of organic carbon fractions were studied. Treatments were no- tillage (NT), conventional tillage (CT), and four cropping patterns viz: sole maize, sole cowpea, maize-cowpea intercrops and control (no crop). Soil samples were analysed for particle size distribution (PSD); aggregation ratio (AR), mean- weight diameter (MWD) and aggregated silt+clay (ASC). Mass fractal dimension (Dm) was obtained from PSD; while fragmentation fractal dimension (Df) was obtained from aggregate sizes. Total organic carbon (TOC), free and occluded particulate organic carbon (fPOC and oPOC), were measured. Results showed that structural stability at micro-aggregate scale measured by aggregated silt + clay (ASC) was significantly (p &lt; 0.05) highest for NT (4.07) than CT (1.58). The CT significantly (P ≤ 0.05) reduced the larger aggregate fraction (5.66-2.00 mm). The difference in fractal dimensions was significantly higher with NT than control with CT. Lower difference between Dm and Df with CT represents high- er degree of fragmentation of aggregates. Correlation showed significant positive linear relationships between Dm and sand (p &lt; 0.05, r = 0.627) and negative rela- tionship with silt and clay (r = -0.675). Therefore, fractal dimensions derived from aggregates sizes rather than particle size distribution reflected the impact of land management practices on fragmentation of aggregates of most tropical soils.

Sex-Specific Association Between Serum Uric Acid and Retinal Microvessels.

BackgroundAs epidemiological findings are still controversial, animal experiments have probed into the potential link between uric acid and damage to microvessels. The present study examined the association of serum uric acid (SUA) with the retinal vascular caliber and retinal vascular fractal dimension (Df) in males and females utilizing a cross-sectional study design.Material/MethodsA total of 2169 subjects from 7 sampling units were enrolled. Retinal vascular parameters were analyzed with a semi-automated computer-based program. The central retinal arteriolar equivalent, central retinal venular equivalent, and Df were linearly and categorically measured in males and females and at various SUA levels.ResultsThe analysis revealed that per SD SUA increase was associated with an increase of 0.848 μm in the arteriolar caliber, and an increase of 1.618 μm in the venular caliber only in females. No significant correlation was found between Df and SUA in females or in males. Further adjusted for more cardiovascular risk factors did not change the results.ConclusionsBy exploring a Chinese coastal population, we elucidate the association between SUA with retinal arterioles and venules in females. Df, as a mathematical index of retinal blood vascular complexity, is not correlated with SUA or hyperuricemia.

Mussel inspired bacterial denitrification of water using fractal patterns of polydopamine

Nitrate is currently one of the most significant causes of water pollution in many parts of the world due to its detrimental effects on humans and the environment. The purpose of this study was to find a novel immobilization method based on bacterial adsorption to adhesive coating material, for use in water denitrification. The fractal formation capability of polydopamine (PDA) allowed coating of the surface of in-house asymmetric polyethersulfone (PES) beads (1.65–2.35 mm in diameter), and immobilizing the denitrifying bacteria Pseudomonas stutzeri with noticeable denitrification potential, on the surface of hyper-branched PDA coated beads. For surface characterization, SEM, wettability measurement, and ATR-FTIR spectroscopy were performed. Nitrate and nitrite concentrations were measured by APHA standard method 4500-NO3−-B and a colourimetric method using two reagents respectively. The effects of temperature, pH and different carbon sources (Acetic acid, methanol, and ethanol) on the denitrification process were also investigated. The results revealed that the bacterial immobilization on PES surface with fractal patterns of PDA (with fractal dimension (Df) value of 1.57) was successful, and the optimum parameters for nitrate removal were established as 25 °C, pH = 8, and 420 mg/L ethanol as the carbon source. Finally, this research showed that under the optimum conditions the immobilized bacteria exhibited 100 % removal efficiency for 28 mg of NO3–N in 22 h (removal rate: 8.06 mg NO3-N/h/mg biomass of bacteria). We found that the immobilization of bacteria on the PDA coated beads is practicable and that the denitrification rate is adequate.