Confinement induces internal flows in adherent cell aggregates.

During mesenchymal migration, F-actin protrusion at the leading edge and actomyosin contraction determine the retrograde flow of F-actin within the lamella. The coupling of this flow to integrin-based adhesions determines the force transmitted to the extracellular matrix and the net motion of the cell. In tissues, motion may also arise from convection, driven by gradients in tissue-scale surface tensions and pressures. However, how migration coordinates with convection to determine the net motion of cellular ensembles is unclear. To explore this, we study the spreading of cell aggregates on adhesive micropatterns on compliant substrates. During spreading, a cell monolayer expands from the aggregate towards the adhesive boundary. However, cells are unable to stabilize the protrusion beyond the adhesive boundary, resulting in retraction of the protrusion and detachment of cells from the matrix. Subsequently, the cells move upwards and rearwards, yielding a bulk convective flow towards the centre of the aggregate. The process is cyclic, yielding a steady-state balance between outward (protrusive) migration along the surface, and 'retrograde' (contractile) flows above the surface. Modelling the cell aggregates as confined active droplets, we demonstrate that the interplay between surface tension-driven flows within the aggregate, radially outward monolayer flow and conservation of mass leads to an internal circulation.

Effects and prediction of cognitive load on encoding model of brain response to auditory and linguistic stimuli in educational multimedia.

Multimedia is extensively used for educational purposes. However, certain types of multimedia lack proper design, which could impose a cognitive load on the user. Therefore, it is essential to predict cognitive load and understand how it impairs brain functioning. Participants watched a version of educational multimedia that applied Mayer's principles, followed by a version that did not. Meanwhile, their electroencephalography (EEG) was recorded. Subsequently, they participated in a post-test and completed a self-reported cognitive load questionnaire. The audio envelope and word frequency were extracted from the multimedia, and the temporal response functions (TRFs) were obtained using a linear encoding model. We observed that the behavioral data are different between the two groups and the TRFs of the two multimedia versions were different. We saw changes in the amplitude and latencies of both early and late components. In addition, correlations were found between behavioral data and the amplitude and latencies of TRF components. Cognitive load decreased participants' attention to the multimedia, and semantic processing of words also occurred with a delay and smaller amplitude. Hence, encoding models provide insights into the temporal and spatial mapping of the cognitive load activity, which could help us detect and reduce cognitive load in potential environments such as educational multimedia or simulators for different purposes.

Neuromonitoring in pre-post and intraoperative total hip replacement surgery in type 4 high-riding developmental dysplasia of the hip.

OBJECTIVE: The choice approach to treating congenital dislocation of the hip joint is total hip replacement (THR). One of the severe but uncommon complications of THR is nerve damage. The most common nerve injury associated with total hip arthroplasty (THA) is sciatic nerve palsy, and the second typical nerve damage with THA is femoral nerve paralysis. PATIENTS AND METHODS: In this prospective cohort study, 35 patients with type 4 high riding developmental dysplasia of the hip (DDH) who were candidates for THA were enrolled. The somatosensory evoked potential (SSEP), motor evoked potential (MEP), and electromyography (EMG) were measured pre-post and intraoperatively to check the status of the sciatic and femoral nerves. After collecting the mentioned information, the data was analyzed by SPSS V. 26 software. RESULTS: Out of 35 patients with DDH type 4 who were candidates for THR, nine patients showed a 50 percent decrease in SSEP amplitude, and six patients showed a 10 percent decrease in SSEP latency. One patient during and two patients after the surgery showed more than an 80 percent decrease in MEP amplitude. Meanwhile, 14 patients showed abnormal spikes during and two patients after surgery regarding EMG. All patients with disturbed neurophysiological findings reverted to normal in the further investigation during follow-up. No correlation was found between increasing limb shortness and these modalities. CONCLUSIONS: Using neuromonitoring techniques during Total Hip Arthroplasty (THA) can help identify potential early nerve damage, prevent post-surgical complications, and improve high-riding DDH patient outcomes.

Analysis of reproduction success, growth and milk trajectories and response to nutritional challenge in two Alpine goat lines selected on divergent longevity.

This study aims to investigate whether the variation in reproduction success, growth, and milk trajectories is associated with different adaptive strategies in the short term (response to an acute nutritional challenge), using two Alpine goat lines. A total of 382 Alpine goats (179 low longevity (low_LGV) and 203 high longevity (high_LGV)), selected for divergent functional longevity from a commercial population, were monitored for 4 years and recorded for BW, reproduction and milking performance. Every year, an average of fifty primiparous goats were exposed to a 2-d nutritional challenge in early lactation. A polynomial model was used to analyse the lifetime trajectory of lactation and BW. A piecewise model was used to analyse the individual milk yield and responses of milk components to the nutritional challenges. The statistical analysis revealed that the two lines had a similar performance for total milk yield in the first lactation, BW at birth and at first kidding, litter size and weight, kidding interval and interval from the first insemination to conception. BW trajectories revealed that low_LGV goats had a greater BW in pregnancy but then lost more weight in early lactation compared to high_LGV goats, which showed a greater BW after kidding. Milk trajectories showed that the high_LGV goats had a higher initial milk yield, an earlier but less marked lactation peak and more persistency in milk production in late lactation than low_LGV goats. Except for milk protein content, quite similar response and recovery profiles of milk yield and milk fat content were observed during the challenge for both lines. The response to the challenge was positively correlated to the initial level of milk production in early lactation but negatively correlated with milk production decline after the peak. This finding suggests that the low_LGV goats were more adapted to allocate resources to meet an expected physiological change such as gestation and lactation. However, high_LGV goats allocate more than low_LGV goats for structural mass and may better cope with an unexpected environmental change such as nutritional deficit.

Assessment of instantaneous cognitive load imposed by educational multimedia using electroencephalography signals.

The use of multimedia learning is increasing in modern education. On the other hand, it is crucial to design multimedia contents that impose an optimal amount of cognitive load, which leads to efficient learning. Objective assessment of instantaneous cognitive load plays a critical role in educational design quality evaluation. Electroencephalography (EEG) has been considered a potential candidate for cognitive load assessment among neurophysiological methods. In this study, we experiment to collect EEG signals during a multimedia learning task and then build a model for instantaneous cognitive load measurement. In the experiment, we designed four educational multimedia in two categories to impose different levels of cognitive load by intentionally applying/violating Mayer's multimedia design principles. Thirty university students with homogenous English language proficiency participated in our experiment. We divided them randomly into two groups, and each watched a version of the multimedia followed by a recall test task and filling out a NASA-TLX questionnaire. EEG signals are collected during these tasks. To construct the load assessment model, at first, power spectral density (PSD) based features are extracted from EEG signals. Using the minimum redundancy - maximum relevance (MRMR) feature selection approach, the best features are selected. In this way, the selected features consist of only about 12% of the total number of features. In the next step, we propose a scoring model using a support vector machine (SVM) for instantaneous cognitive load assessment in 3s segments of multimedia. Our experiments indicate that the selected feature set can classify the instantaneous cognitive load with an accuracy of 84.5 ± 2.1%. The findings of this study indicate that EEG signals can be used as an appropriate tool for measuring the cognitive load introduced by educational videos. This can be help instructional designers to develop more effective content.

Active Regulation of Pressure and Volume Defines an Energetic Constraint on the Size of Cell Aggregates.

We explore the relationship between the nonequilibrium generation of myosin-induced active stress within the F-actin cytoskeleton and the pressure-volume relationship of cellular aggregates as models of simple tissues. We find that due to active stress, aggregate surface tension depends upon its size. As a result, both pressure and cell number density depend on size and violate equilibrium assumptions. However, the relationship between them resembles an equilibrium equation of state with an effective temperature. This suggests that bulk and surface properties of aggregates balance to yield a constant average work performed by each cell on their environment in regulating tissue size. These results describe basic physical principles that govern the size of cell aggregates.

Cell-Matrix Elastocapillary Interactions Drive Pressure-based Wetting of Cell Aggregates.

Cell-matrix interfacial energies and the energies of matrix deformations may be comparable on cellular length-scales, yet how capillary effects influence tis sue shape and motion are unknown. In this work, we induce wetting (spreading and migration) of cell aggregates, as models of active droplets onto adhesive substrates of varying elasticity and correlate the dynamics of wetting to the balance of interfacial tensions. Upon wetting rigid substrates, cell-substrate tension drives outward expansion of the monolayer. By contrast, upon wetting compliant substrates, cell substrate tension is attenuated and aggregate capillary forces contribute to internal pressures that drive expansion. Thus, we show by experiments, data-driven modeling and computational simulations that myosin-driven 'active elasto-capillary' effects enable adaptation of wetting mechanisms to substrate rigidity and introduce a novel, pressure-based mechanism for guiding collective cell motion.

Friction on incommensurate substrates: Role of anharmonicity and defects.

We present molecular dynamics simulations of one- and two-dimensional bead-spring models sliding on incommensurate substrates after an initial kick, in the case where the coupling to the underlying substrate is weak, i.e., energy can dissipate only into the internal degrees of freedom of the sliding object, but not into the substrate below. We investigate how sliding friction is affected by structural defects and interaction anharmonicity. In their absence, we confirm earlier findings, namely, that at special resonance sliding velocities, friction is maximal. When sliding off-resonance, partially thermalized states are possible, whereby only a small number of vibrational modes becomes excited, but whose kinetic energies are already Maxwell-Boltzmann distributed. Anharmonicity and defects typically destroy partial thermalization and instead lead to full thermalization, implying much higher friction. For sliders with periodic boundaries, thermalization begins with vibrational modes whose spatial modulation is compatible with the incommensurate lattice. For a disk-shaped slider, modes corresponding to modulations compatible with the slider radius are initially the most dominant. By tuning the mechanical properties of the slider's edge, this effect can be controlled, resulting in significant changes in the sliding distance covered.

Detection of Fasciola Hepatica in Lori Sheep Using Polymerase Chain Reaction and Conventional Diagnostic Methods in Western Iran.

Fascioliasis is an emerging and important food and water-borne disease in human communities which has become one of the most important health challenges in countries, like Iran. It causes weight loss, a decrease in feed conversion ratio as well as milk and meat production, and also reduces fertility in animals the prevalence of fasciolosis is increasing in some regions of the world due to various factors. Different methods have been used for the detection of Fasciola hepatica in animals. This study is the first to detect F. hepatica in Lori sheep using polymerase chain reaction (PCR) and conventional diagnostic methods in Western Iran. During three months, 195 fecal samples were collected from sheep in Lorestan province, Iran, using the stratified random sampling method. The conventional diagnostic methods, including wet mount microscopic examination and concentration assays, as well as the PCR technique targeting the intergenic spacer gene of F. hepatica, were used for the detection of the parasite in sheep. In total, 4 (2.1%) out of 195 examined stool samples were positive for F. hepatica based on the conventional assays. The PCR test was positive for F. hepatica in7 (3.6%) samples of 195 studied specimens. Statistical analyses of the data revealed that there is a significant difference between the results of diagnostic methods for F. hepatica detection (P=0.0421). Finally, the results showed that PCR has more diagnostic sensitivity, compared to conventional diagnostic methods, including the concentration techniques and microscopic examination. Hence, it can be advised to use PCR for the detection of F. hepatica in sheep.

Environmental Effects of Temperature and Water Potential on Mycelial Growth of Neocosmospora solani and Fusarium spp. Causing Dry Root Rot of Citrus.

This study aimed at evaluating the effect of environmental factors temperature and water potential (Ψw) on the growth of Neocosmospora (Fusarium) solani and three Fusarium species (F. oxysporum, F. equiseti and F. brachygibbosum) associated with citrus dry root rot and to determine the optimum and marginal rate for their growth. The effects of incubation temperature (5-40 °C), water potentials (Ψw) (- 15.54; - 0.67 MPa) (0.89-0.995 aw) and their interaction (5-30 °C) was evaluated on the in vitro radial growth rates of Fusarium spp. and on their lag phase. Secondary models were used to model the combined effect of these factors on radial growth rate. The results underlined a highly significant effects (P < 0.001) of Ψw and temperature and their interactions on radial growth rates and lag phases (λ). The Four studied species were shown tolerant to a temperature of 35 °C with an optimum mycelial growth at 30 for N. solani and F. oxysporum and at 25 °C for F. equiseti and F. brachygibbosum. However, no growth was observed at both temperatures 5 and 40 °C and at Ψw of - 9.68 MPa (0.93 aw). The optimum water potential for growth was ≥- 2.69 MPA (>0.98 aw). The results from the polynomial model and response surface showing good agreement between observed and predicted values. The external validation on citrus fruit indicated slight differences between predicted and observed values of radial growth. The results of this study will be beneficial for understanding the ecological knowledge of these species and thereby limited preventively their occurrence.

An ecological approach to the development of an active aging measurement in urban areas (AAMU).

BACKGROUND: An essential element in the process of "aging well" is the concept of Active Aging (AA). To propose an operational definition of Active Aging, the present study seeks to develop a new measurement tool through an ecological approach. The aim is to recognize significant indicators that play a role in assessing AA in urban areas. METHODS: This study was conducted through a two-phase process of consensus-building: 1) identifying a set of indicators that were likely candidates for inclusion based on literature review, and 2) a two-round modified Delphi survey using an international panel of academic experts in environmental sciences and gerontology to achieve consensus on the importance of the extracted indicators and validate the items. The panelists were asked to complete a researcher-developed questionnaire with an 11-point Likert scale based on the indicators derived in phase 1. Finally, the Delphi survey's valid indicators and criteria were utilized to develop the measurement tool. RESULTS: At the outset, a list of 111 indicators of AA was prepared through the desk study. A panel of 22 experts reviewed the extracted items and arrived at a consensus on 99 items in the first round and finalised in the second round. Thematic analysis of the panelists' open-ended responses revealed new concepts that would be explicitly considered by the consensus group. This developed measurement scale consists of five domains, i.e., individual, spatial, socio-economic, governance, and health-related, which contain 15 criteria and 99 indicators. CONCLUSIONS: The present researchers have developed the active aging measure for urban settlements (AAMU), which can be used both by policy-makers and as an informal self-reported statement among the elderly. AAM's results in the elderly's residential environmental communities can improve policy-making to address urban design to sustain an active, healthy life among older people in urban environments.

Smoking and disability pension: a systematic review and meta-analysis.

OBJECTIVES: Smoking has negative consequences on occupational health. The current meta-analysis was conducted with the aim to pool the studies about smoking and increased disability pension. STUDY DESIGN: Systematic review and meta-analysis. METHODS: Articles were found in the scientific literature using keywords, and searching was limited to prospective cohort studies that had been published before August 2018. Based on the inclusion and exclusion criteria, 23 prospective cohort studies were selected. The analyses were carried out on the basis of the random-effects method. Subgroup analysis was also carried out. Finally, the bias of publication was examined using Begg's test, the Egger test, the trim-and-fill method, and the funnel plot. RESULTS: Twenty-three studies were included. The results showed a positive association between smoking and disability pension, with a risk ratio (RR) of 1.41 and 95% confidence interval (95% CI) of 1.30-1.53 (P < 0.001). In men, the RR was equal to 1.48 and 95% CI was equal to 1.30-1.68 (P < 0.001). In women, the RR was equal to 1.23 and 95% CI was equal to 1.09-1.37 (P = 0.001). In current smokers, the RR was equal to 1.41 and 95% CI was equal to 1.26-1.57 (P < 0.001). In former smokers, the RR was equal to 1.16 and 95% CI was equal to 1.05-1.29 (P = 0.003). Qualitative evaluation showed that the studies had a low level of selection bias, data collection bias, and withdrawal and dropout bias. CONCLUSIONS: Smoking is a risk factor for increasing disability pension, and men are at higher risk of disability pension. In addition, both current and former smokers are in high risk of disability pension. Overall, it can be concluded that smoking is a risk factor for occupational health.

Association between job strain and sick leave: a systematic review and meta-analysis of prospective cohort studies.

OBJECTIVES: Sick leave imposes large costs on society, and job strain is one of the factors leading to sick leave. A systematic review and meta-analysis of longitudinal studies was conducted to address job strain and its association with sick leave. STUDY DESIGN: This is a systematic review and meta-analysis. METHODS: PubMed and Scopus databases were reviewed, in addition to searches in Google Scholar and ResearchGate to ensure the inclusion of any grey literature articles. After screening the studies, using Preferred Reporting Items for Systematic Reviews and Meta-Analyses principles, articles with longitudinal design were found desirable for meta-analysis. The risk ratio (RR) and 95% confidence interval (CI) were calculated, and publication bias was examined. RESULTS: Eighteen longitudinal cohort studies were selected. Job strain and sick leave were found to be associated, and the RR of this association was equal to 1.44. Risk of sick leave based on job strain in men and women was equal to 1.66 (95% CI: 1.15-2.40) and 1.16 (95% CI: 1.08-1.24), respectively. The results showed no publication bias as per Begg's test. CONCLUSIONS: Job strain was associated with an increased risk of sick leave. Occupational conditions have significant effects on the risk of sick leave-one of which is job strain. Therefore, improving organisational conditions can have a significant impact on reducing sick leave.

Is job strain a risk factor for musculoskeletal pain? A systematic review and meta-analysis of 21 longitudinal studies.

OBJECTIVE: Given that job strain can be a risk factor for health, the researchers looked at the meta-analysis in which consequences of musculoskeletal pain in job strain is reviewed. STUDY DESIGN: Systematic review and meta-analysis. METHODS: After searching in databases based on keywords, studies were retrieved until January 2019. The extracted studies were combined altogether and the risk ratio was calculated. In addition, additional analysis was conducted at the end. RESULTS: The results showed that job strain as a risk factor for musculoskeletal pain was 1.62. The risk ratio is equal to 1.38 in men and 1.28 in women. Begg (P = 0.629) and Egger (P = 0.251) tests were not significant but trim-and-fill method imputed 9 missing studies. CONCLUSIONS: Job strain was a risk factor for physical health and increased the risk of musculoskeletal pain. Therefore, it seems psychologically healthy work environment is essential for the prevention of health problems.

Job strain and mortality ratio: a systematic review and meta-analysis of cohort studies.

OBJECTIVES: Research has explored the relationship between job strain and adverse effects on physical and psychological health. Accordingly, the effects of job strain on mortality risk were pooled based on longitudinal studies. STUDY DESIGN: Systematic review and meta-analysis. METHODS: Both researchers searched for published articles in scientific databases until May 2019. Then, the articles were screened based on the inclusion and exclusion criteria. The results were combined, and analyses of subgroups and reviewing the bias of the publication were performed as well. RESULTS: Seventeen longitudinal studies included in the meta-analysis were from three continents: Europe, Asia, and America. The risk ratio (RR) of mortality based on job strain was equal to 1.20, with a confidence interval (CI) of 1.04-1.37 (P = 0.00.10). In men, the RR is 1.21, and the CI is 1.02-1.44 (P = 0.032), and in women, the RR is 0.97 and CI is 0.84-1.12 (P = 0.686). Evaluation of publication bias indicated nothing significant. DISCUSSION: Based on the findings, it was found that job strain was a risk factor for mortality, and this finding was more appropriate for men. Hence, reducing job strain can be a deterrent against the dangers that threaten health.

[Bruch's membrane opening minimum rim width : Correlation and diagnostic accuracy in comparison to peripapillary retinal nerve fiber layer thickness]. / Die auf der Bruchschen Membranöffnung basierende Minimale Randsaumweite : Korrelation und diagnostische Genauigkeit im Vergleich zur peripapillären retinalen Nervenfaserschichtdicke.

BACKGROUND: Glaucoma is one of the main causes of blindness in the Western hemisphere. Because the disease often painlessly progresses it remains unnoticed until major optic nerve head damage occurs in many cases. That is why new, more sensitive diagnostic methods are needed. Bruch's membrane opening minimum rim width (BMO-MRW), measured with the new glaucoma module premium edition (GMPE) was recently introduced as a more accurate tool to detect glaucomatous changes. The purpose of this study was to assess the correlation of SPECTRALIS® spectral domain optical coherence tomography (SD-OCT) and the GMPE anatomic positioning module (APS module) for retinal nerve fiber layer thickness (RNFLT) measurements. The second aim was to assess the diagnostic accuracy of BMO-MRW. METHODS: Prospective study of 41 eyes (41 patients) with glaucoma and 26 eyes from 26 healthy controls. Scans were obtained using SPECTRALIS® SD-OCT and RNFLT was measured with both modules and compared using Spearman's rank test. The BMO-MRW was assessed by GMPE. Sensitivity, specificity and area under receiver operating characteristics curves (AUROC) of each sector of the optic nerve were calculated and compared using the method of Delong et al. RESULTS: We found a positive correlation (0.694-0.955, p < 0.0001) between RNFLT measurements by standard SD-OCT and all diameters of RNFLT of APS module within all sectors. The AUROC of RNFLT in standard SD-OCT was 0.693 for the inferior nasal sector (NI) and BMO-MRW was 0.85 in NI. The difference in AUROC was statistically significant (p = 0.0049). No other sector showed statistically significant differences. CONCLUSION: The RNFLT measurements of both modules showed a positive correlation and appear to be comparable. The BMO-MRW in one sector (NI) showed a significantly higher accuracy of measurement than standard RNFLT. All other sectors showed a comparable accuracy of measurement.

Resting-State Functional Connectivity in Popular Targets for Deep Brain Stimulation in the Treatment of Major Depression: An Application of a Graph Theory.

We examined the functional connectivity of subcallosal cingulate gyrus (SCG), nucleus accumbens (NAc), and ventral caudate (VCa), the main target areas for the treatment of major depression disorder (MDD), using deep brain stimulation (DBS). MDD is one of the most common diseases in the world, and approximately 30% of MDD patients do not respond to common therapies, including psychotherapy and antidepressant medications. Alternatively, DBS has been recently used to treat MDD. Resting state fMRI was obtained from seventeen healthy subjects and seven MDD patients. The functional connectivity network of the brain was constructed for all subjects and measured by the `degree' value for each SCG, NAc, and VCa regions using the graph theory analysis. The results show that the degree values of VCa and the left SCG are higher in the MDD group than the healthy group. Furthermore, the patterns of the degree values were different for the right and left hemispheres in MDD patients. Our findings suggest that degree values and their patterns have a potential to be used as diagnosis tools to detect the brain areas with abnormal functional connectivity.

Cytosolic expression of functional Fab fragments in Escherichia coli using a novel combination of dual SUMO expression cassette and EnBase® cultivation mode.

AIMS: The Escherichia coli expression system is highly effective in producing recombinant proteins. However, there are some limitations in this system, especially in obtaining correctly folded forms of some complex proteins such as Fab fragments. To improve the solubility and folding quality of Fab fragments, we have examined the effect of simultaneous application of a SUMO fusion tag, EnBase® cultivation mode and a redox mutant strain in the E. coli expression system. METHODS AND RESULTS: A bicistronic gene construct was designed to express an antivascular endothelial growth factor (VEGF) Fab fragment as a model system. The construct contained a dual SUMO fusion gene fragment to encode SUMO-tagged heavy and light chains. While the expression of the construct in batch cultures of BL21 or SHuffle® transformants produced insoluble and unfolded products, the induction of the transformants in EnBase® medium resulted in soluble and correctly folded Fab fragment, reaching as high as 19% of the total protein in shuffle strain. The functional assays indicated that the biological activity of the target Fab is similar to the commercial anti-VEGF, Lucentis® . CONCLUSIONS: This study demonstrated that the combination of SUMO fusion technology, EnBase® cultivation system and recruiting a redox mutant of E. coli can efficiently enhance the solubility and productivity of recombinant Fab fragments. SIGNIFICANCE AND THE IMPACT OF THE STUDY: The presented strategy provides not only a novel method to produce soluble and active form of an anti-VEGF Fab but also may use in the efficient production of other antibody fragments.

Nitrogen-doped amorphous carbon-silicon core-shell structures for high-power supercapacitor electrodes.

We report successful deposition of nitrogen-doped amorphous carbon films to realize high-power core-shell supercapacitor electrodes. A catalyst-free method is proposed to deposit large-area stable, highly conformal and highly conductive nitrogen-doped amorphous carbon (a-C:N) films by means of a direct-current plasma enhanced chemical vapor deposition technique (DC-PECVD). This approach exploits C2H2 and N2 gases as the sources of carbon and nitrogen constituents and can be applied to various micro and nanostructures. Although as-deposited a-C:N films have a porous surface, their porosity can be significantly improved through a modification process consisting of Ni-assisted annealing and etching steps. The electrochemical analyses demonstrated the superior performance of the modified a-C:N as a supercapacitor active material, where specific capacitance densities as high as 42 F/g and 8.5 mF/cm2 (45 F/cm3) on silicon microrod arrays were achieved. Furthermore, this supercapacitor electrode showed less than 6% degradation of capacitance over 5000 cycles of a galvanostatic charge-discharge test. It also exhibited a relatively high energy density of 2.3 × 103 Wh/m3 (8.3 × 106 J/m3) and ultra-high power density of 2.6 × 108 W/m3 which is among the highest reported values.

Enhancing purification efficiency of affinity functionalized composite agarose micro beads using Fe3O4 nanoparticles.

In this work, a series of magnetic and nonmagnetic agarose matrices were fabricated for protein purification. Certain amounts of Fe3O4 nanoparticles were encapsulated in agarose beads to form composite magnetic matrices with enhanced purification efficiency. Structure and morphology of prepared matrices were studied by optical and scanning electron microscopes, FT-IR, and BET-BJH analysis. The prepared matrices had regular spherical shape, followed by a uniform size distribution. By nanoparticles addition, the number of mesopores decreased while population of pores with radius ≤10nm increased; thus, higher specific area achieved. According to VSM results, magnetization degree was one of the characteristics affected by agarose content of the beads. A dye ligand, Cibacron Blue F3GA (CB), was covalently bound to beads to adsorb Bovine serum albumin. CB concentration was determined by elemental analysis. It was shown that magnetic beads hold higher CB concentrations than nonmagnetic ones due to higher specific area. As a result, magnetic 8%-agarose beads had the highest affinity adsorption capacity in static experiments. Moreover, breakthrough curves were monitored to calculate dynamic binding capacity. And, it was shown that magnetic 4%-agarose had the highest adsorbing amount (6.00mg/mL). It was implied that pore diffusion in magnetic 4%-agarose may be the reason for higher dynamic capacity. Plus, column efficiency was evaluated. It was revealed that all magnetic beads had lower HETP (0.11, 0.12 and 0.11cm for magnetic 4, 6, and 8%-agarose beads) than nonmagnetic ones (P-value<0.05).