Small-diameter Fibers Research Articles

A comparative study of single-needle and coaxial electrospun amyloid-like protein nanofibers to investigate hydrophilic drug release behavior

In this study, nanofibers containing an amyloid-like bovine serum albumin (AL-BSA) carrier and a model drug (ampicillin) were produced by electrospinning. The release behavior of ampicillin was compared from electrospun nanofibers prepared as either coaxial or single-needle types. SEM images showed that the membranes had a uniform and smooth structure and the core/shell fibers were found to be thicker than the core fibers. Core/shell production was proved by transmission electron microscopy images. Fourier transform infrared spectroscopy indicated the existence of compatibility between ampicillin and the AL-BSA matrix. The in vitro antimicrobial properties of ampicillin were studied through the comparison of bacterial inhibition zones and ampicillin was found to be more effective against Gram-positive Staphylococcus aureus than Gram-negative Escherichia coli. Moreover, in vitro drug release tests were conducted to explore the relationship between the shell thickness and the drug release rate. A burst release was observed for all membranes owing to the small fiber diameters and thus short diffusion lengths. For core membranes, the drug release mechanism followed Fickian transport, which was close to zero-order kinetic. A typical biphasic release mechanism was observed for the core/shell nanofibers. Overall, we present the first evidence of AL-BSA as a potential core/shell drug mediator.

Localized Delivery of Cl-Amidine From Electrospun Polydioxanone Templates to Regulate Acute Neutrophil NETosis: A Preliminary Evaluation of the PAD4 Inhibitor for Tissue Engineering.

Upon interaction, neutrophils can potentially release neutrophil extracellular traps (NETs) on the surface of an implanted electrospun template, which may be a significant preconditioning event for implantable biomaterials of yet unknown consequences. In this study, we investigated the potential of polydioxanone templates as a delivery vehicle for Cl-amidine, an inhibitor of peptidyl arginase deiminase 4 (PAD4), and if drug elution could attenuate PAD4-mediated NETosis in the vicinity of implanted templates. Electrospun polydioxanone templates were fabricated with distinct architectures, small diameter (0.4 μm) or large diameter (1.8 μm) fibers, and incorporated with 0–5 mg/mL Cl-amidine to examine dose-dependent effects. Acute neutrophil-template interactions were evaluated in vitro with freshly isolated human neutrophils and in vivo with a rat subcutaneous implant model. The in vitro results suggest large diameter templates with 0 mg/mL Cl-amidine significantly attenuate NETosis compared to small diameter templates. As the drug concentration increased, NETosis was significantly decreased on small diameter templates in a dose-dependent manner. The opposite was observed for large diameter templates, indicating multiple mechanisms of NETosis may be regulating neutrophil template preconditioning. Similar results were observed in vivo, verifying local NETosis inhibition by Cl-amidine eluting templates in a physiological environment. Importantly, large diameter templates with Cl-amidine enhanced neutrophil invasion and survival, supporting the potential for long-term modulation of tissue integration and regeneration. This preliminary study demonstrates a novel delivery vehicle for Cl-amidine that can be used to regulate acute NETosis as the potential critical link between the innate immune response, inflammation, and template-guided tissue regeneration.

Membrane contactor for subsea natural gas dehydration: Model development and sensitivity study

A mathematical model of a membrane contactor using triethylene glycol (TEG) for dehydration of natural gas at subsea operation conditions has been developed. The goal for the membrane contactor is to dehydrate the natural gas to transport pipeline specifications, which are −19 °C at 69 barg. The membrane contactor model is based on a hollow fiber configuration with the gas in the shell side and the liquid absorbent inside the fiber. The shell side gas is modelled as one-dimensional on the assumption of turbulent flow, while the fiber/lumen side is modelled as two-dimensional flow due to the laminar flow. Orthogonal collocation is applied to solve the two-point boundary value problem. The developed model is validated against proprietary high pressure experimental data for dehydration of natural gas with TEG in a membrane contactor. The H2O molar flow removed from the gas phase is predicted by the model with a mean absolute error range of 3–7% compared to the experimental results, based on two methods of calculation due to uncertainty in experimental basis. A sensitivity study was performed to evaluate the effect of membrane properties and operation conditions on the dehydration performance. The main findings are that preferred membrane properties from a separation performance point of view are thin membrane, small fiber diameter, long membrane module, high porosity and high permeability. But, the production of the membrane, stability and long term operation also need to be considered in the selection of membrane material and module parameters. For high pressure subsea operation it is found that the use of a dense layer on the top of the porous support could be favourable to prevent wetting of the membrane. It is found that a wetting of 1% already provides a significant drop in separation performance. For the operation conditions the main findings are that high pressure and low temperature are favourable for the separation. Increasing the gas and liquid flow gives increased flux over the membrane, but also results in increased pressure drop in the module. However, as the membrane contactor will be placed in a system with regeneration of the solvent, the operation conditions should be optimized considering the whole system.

Fabrication and Characterization of Electrospun Polysulfone (PSF)/Organo-Montmorillonite (O-MMT) Nanostructured Membranes

Polymeric membranes infused with clays have attracted researchers for it poses a great potential in water treatment applications. In this study, polysulfone (PSF) has been infused with organo-montmorillonite (O-MMT) clay to fabricate membranes through electrospinning and were subjected into different characterizations to find out the effect of adding the clay to the polymer.Four sampleswith different amounts of O-MMT have been fabricated (Pure PSF, 1% O-MMT, 3% O-MMT and 5% O-MMT). The fiber morphology, fiber diameter,surface chemical composition, hydrophobicity, and mechanical properties of these samples were studied. Preliminary investigationhas revealed that shallow pores and smaller fiber diameter were formed with increasing O-MMT concentration. Molecular interaction between the PSF and O-MMT was also revealed through the FT-IR analysis. With regards to contact angle, there are no significant differences between the measurements for each PSF/O-MMT blend. Improvements in the mechanical properties of the samples were also observed as the O-MMT concentration increases.

Imaging of electrical activity in small diameter fibers of the murine peripheral nerve with virally-delivered GCaMP6f

Current neural interfaces are hampered by lack of specificity and selectivity for neural interrogation. A method that might improve these interfaces is an optical peripheral nerve interface which communicates with individual axons via optogenetic reporters. To determine the feasibility of such an interface, we delivered the genetically encoded calcium indicator GCaMP6f to the mouse peripheral nerve by intramuscular injection of adenoassociated viral vector (AAV1) under the control of the CAG (chicken beta actin- cytomegalovirus hybrid promoter). Small diameter axons in the common peroneal nerve were transduced and demonstrated electrically inducible calcium transients ex vivo. Responses to single electrical stimuli were resolvable, and increasing the number of stimuli resulted in a monotonic increase in maximum fluorescence and a prolongation of calcium transient kinetics. This work demonstrates the viability of using a virally-delivered, genetically-encoded calcium indicator to read-out from peripheral nerve axons.

Thermally Optimized Polarization-Maintaining Photonic Crystal Fiber and Its FOG Application.

In this paper, we propose a small-diameter polarization-maintaining solid-core photonic crystal fiber. The coating diameter, cladding diameter and other key parameters relating to the thermal properties were studied. Based on the optimized parameters, a fiber with a Shupe constant 15% lower than commercial photonic crystal fibers (PCFs) was fabricated, and the transmission loss was lower than 2 dB/km. The superior thermal stability of our fiber design was proven through both simulation and measurement. Using the small-diameter fiber, a split high precision fiber optic gyro (FOG) prototype was fabricated. The bias stability of the FOG was 0.0023 °/h, the random walk was 0.0003 °/, and the scale factor error was less than 1 ppm. Throughout a temperature variation ranging from −40 to 60 °C, the bias stability was less than 0.02 °/h without temperature compensation which is notably better than FOG with panda fiber. As a result, the PCF FOG is a promising choice for high precision FOG applications.

Establishing a Mouse Model of a Pure Small Fiber Neuropathy with the Ultrapotent Agonist of Transient Receptor Potential Vanilloid Type 1.

Patients with diabetes mellitus (DM) or those experiencing the neurotoxic effects of chemotherapeutic agents may develop sensation disorders due to degeneration and injury of small-diameter sensory neurons, referred to as small fiber neuropathy. Present animal models of small fiber neuropathy affect both large- and small-diameter sensory fibers and thus create a neuropathology too complex to properly assess the effects of injured small-diameter sensory fibers. Therefore, it is necessary to develop an experimental model of pure small fiber neuropathy to adequately examine these issues. This protocol describes an experimental model of small fiber neuropathy specifically affecting small-diameter sensory nerves with resiniferatoxin (RTX), an ultrapotent agonist of transient receptor potential vanilloid type 1 (TRPV1), through a single dose of intraperitoneal injection, referred to as RTX neuropathy. This RTX neuropathy showed pathological manifestations and behavioral abnormalities that mimic the clinical characteristics of patients with small fiber neuropathy, including intraepidermal nerve fiber (IENF) degeneration, specifically injury in small-diameter neurons, and induction of thermal hypoalgesia and mechanical allodynia. This protocol tested three doses of RTX (200, 50, and 10 µg/kg, respectively) and concluded that a critical dose of RTX (50 µg/kg) is required for the development of typical small fiber neuropathy manifestations, and prepared a modified immunostaining procedure to investigate IENF degeneration and neuronal soma injury. The modified procedure is fast, systematic, and economic. Behavioral evaluation of neuropathic pain is critical to reveal the function of small-diameter sensory nerves. The evaluation of mechanical thresholds in experimental rodents is particularly challenging and this protocol describes a customized metal mesh that is suitable for this type of assessment in rodents. In summary, RTX neuropathy is a new and easily established experimental model to evaluate the molecular significance and intervention underlying neuropathic pain for the development of therapeutic agents.

Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes

Objective. Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). Approach. A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. Main results. Recruitment thresholds of individual regenerated fibers with diameters >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90–140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. Significance. Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.

Bone marrow-derived mesenchymal stem cells versus adipose-derived mesenchymal stem cells for peripheral nerve regeneration.

Studies have confirmed that bone marrow-derived mesenchymal stem cells (MSCs) can be used for treatment of several nervous system diseases. However, isolation of bone marrow-derived MSCs (BMSCs) is an invasive and painful process and the yield is very low. Therefore, there is a need to search for other alterative stem cell sources. Adipose-derived MSCs (ADSCs) have phenotypic and gene expression profiles similar to those of BMSCs. The production of ADSCs is greater than that of BMSCs, and ADSCs proliferate faster than BMSCs. To compare the effects of venous grafts containing BMSCs or ADSCs on sciatic nerve injury, in this study, rats were randomly divided into four groups: sham (only sciatic nerve exposed), Matrigel (MG; sciatic nerve injury + intravenous transplantation of MG vehicle), ADSCs (sciatic nerve injury + intravenous MG containing ADSCs), and BMSCs (sciatic nerve injury + intravenous MG containing BMSCs) groups. Sciatic functional index was calculated to evaluate the function of injured sciatic nerve. Morphologic characteristics of nerves distal to the lesion were observed by toluidine blue staining. Spinal motor neurons labeled with Fluoro-Gold were quantitatively assessed. Compared with sham-operated rats, sciatic functional index was lower, the density of small-diameter fibers was significantly increased, and the number of motor neurons significantly decreased in rats with sciatic nerve injury. Neither ADSCs nor BMSCs significantly improved the sciatic nerve function of rats with sciatic nerve injury, increased fiber density, fiber diameters, axonal diameters, myelin sheath thickness, and G ratios (axonal diameter/fiber diameter ratios) in the sciatic nerve distal to the lesion site. There was no significant difference in the number of spinal motor neurons among ADSCs, BMSCs and MG groups. These results suggest that neither BMSCs nor ADSCs provide satisfactory results for peripheral nerve repair when using MG as the conductor for engraftment.

Host gut-derived probiotic bacteria promote hypertrophic muscle progression and upregulate growth-related gene expression of slow-growing Malaysian Mahseer Tor tambroides

In modern aquaculture, dietary supplementation of probiotics is a novel approach for enhancing growth performance of slow-growing fish. However, the actual role of probiotics in regulating muscle growth at cellular and molecular levels in fish still needs to be clarified. In this study, we hypothesized that host gut derived probiotic bacteria would enhance cellular muscle growth, and upregulate growth-related gene expression in slow-growing Malaysian mahseer Tor tambroides. Therefore, three host-associated probiotics (Bacillus sp. AHG22, Alcaligenes sp. AFG22, and Shewanella sp. AFG21) were isolated from the gastro-intestinal tract of T. tambroides and screened based on their digestive enzyme activity. A fishmeal and casein based control diet (40% crude protein and 10% lipid) was formulated, and three different probiotic supplemented diets were prepared by immersing the control diet in each isolated host-derived bacteria, suspended in sterile phosphate buffered saline (PBS), to achieve a final concentration of approximately 1.0 × 108 CFU g−1 feed. Triplicate groups of T. tambroides juveniles (initial weight 1.39 ± 0.06 g) were stocked in twelve glass aquaria (100 L capacity) with stocking density of 20 individuals per aquarium. The feed was applied twice daily at 3.0% of the fish body weight per day for 90 days. Growth performance (weight gain and specific growth rate) of T. tambroides juveniles were significantly higher in Alcaligenes sp. AFG22 and Bacillus sp. AHG22 supplemented diet treatments. Muscle morphometric analysis revealed that dietary supplementation of host-associated probiotic bacteria did not influence the frequency distribution of hyperplastic (class 10) small diameter fibers (≤10 μm). However, hypertrophic (Class 50, Class 60 and Class 70) large diameter fibers (>50 μm) were significantly higher in Alcaligenes sp. AFG22 and Bacillus sp. AHG22 supplemented treatments, indicating that increased growth rate of T. tambroides in these treatments was mostly governed by increased muscle fibers hypertrophy, rather than by hyperplasia. Real-time PCR data demonstrated that the relative mRNA expression of GH and IGF1 was upregulated in juvenile T. tambroides fed the diets supplemented with Alcaligenes sp. AFG22 and Bacillus sp. AHG22. These results indicate that host-derived probiotics, especially Alcaligenes sp. AFG22 and Bacillus sp. AHG22, have a significant potential as autochthonous probiotics for the stimulation of growth performance of slow-growing T. tambroides in aquaculture.

Development and sexual dimorphism of the sonic system in three deep-sea neobythitine fishes and comparisons between upper mid and lower continental slope

Based on morphology, NB Marshall identified cusk-eels (family Ophidiidae) as one of the chief sound-producing groups on the continental slope. Due to food scarcity, we hypothesized that sonic systems will be reduced at great depths despite their potential importance in sexual reproduction. We examined this hypothesis in the cusk-eel subfamily Neobythitinae by comparing sonic morphology in Atlantic species from the upper-mid (Dicrolene intronigra) and deeper continental slope (Porogadus miles and Bathyonus pectoralis) with three Taiwanese species previously described from the upper slope (Hoplobrotula armatus, Neobythites longipes and N. unimaculatus). In all six species, medial muscles are heavier in males than in females. Dicrolene has four pairs of sonic muscles similar to the shallow Pacific species, suggesting neobythitine sonic anatomy is conservative and sufficient food exists to maintain a well-developed system at depths exceeding 1km. The sonic system in Porogadus and Bathyonus was reduced to a single pair of ventral medial muscles that connects to a smaller and thinner swimbladder via a long tendon. Small muscle fiber diameters, a likely indicator of rapid contraction, were present in males of five of the species. However, in Bathyonus, the deepest species (pale coloration, reduced eye size, shorter sonic muscles and longer tendons), muscle fibers were larger suggesting an adaptation to facilitate rapid bladder movement for sound production while using slower contractions and less metabolic energy. The six species separate into three groups in length-weight regressions: the three upper slope species have the greatest weights per unit length, Dicrolene is lower, and the two deep species are further reduced consistent with the hypothesis that food limitation affects sonic anatomy at great depths.

Physicochemical properties and methane adsorption performance of activated carbon nanofibers with different types of metal oxides

In this study, composite PAN-based ACNFs embedded with MgO and MnO2 were prepared by the electrospinning method. The resultant pristine ACNFs, ACNF/MgO and ACNF/MnO2 were characterized in terms of their morphological changes, SSA, crystallinity and functional group with FESEM-EDX, the BET method, XRD and FTIR analysis, respectively. Results from this study showed that the SSA of the ACNF/MgO composite (1893 m2 g–1) is significantly higher than that of the pristine ACNFs and ACNF/MnO2 which is 478 and 430 m2 g–1, respectively. FTIR analysis showed peaks of 476 and 547 cm–1, indicating the presence of MgO and MnO2, respectively. The FESEM micrographs analysis showed a smooth but coarser structure in all the ACNFs. Meanwhile, the ACNF/MgO has the smallest fiber diameter (314.38±62.42 nm) compared to other ACNFs. The presence of MgO and MnO2 inside the ACNFs was also confirmed with EDX analysis as well as XRD. The adsorption capacities of each ACNF toward CH4 were tested with the volumetric adsorption method in which the ACNF/MgO exhibited the highest CH4 adsorption up to 2.39 mmol g–1. Meanwhile, all the ACNF samples followed the pseudo-second order kinetic model with a R2 up to 0.9996.

Composite Fibers from Recycled Plastics Using Melt Centrifugal Spinning.

New methods are being developed to enable the production of value-added materials from high-volume, low-cost feedstocks arising from domestic recycling streams. In this work, recycled bottle-grade polyethylene terephthalate, polystyrene, and polypropylene were spun into fibers from the melt using a centrifugal spinning technique. Mono-component fibers and 50/50 blends of each polymer and a 33/33/33 blend of all three polymers were evaluated. Fiber morphology, chemistry, thermal, and mechanical properties were probed. Fiber diameters ranged from ca. 1 to over 12 µm, with polypropylene fibers having the smallest fiber diameters. Mono-component fibers were generally defect-free, while composite fibers containing polypropylene were beady. Fibers made from polyethylene terephthalate had the highest tensile strength, and the addition of polyethylene terephthalate to the other polymers improved the mechanical properties of the blends. Nano- and micro-fibers from both pure and mixed waste streams are expected to have applications in myriad areas such as ultra/micro-filtration, composites, and insulation.

Blood compatibility and physicochemical assessment of novel nanocomposite comprising polyurethane and dietary carotino oil for cardiac tissue engineering applications

ABSTRACTCardiovascular diseases (CVD) were estimated to claim 17 million lives each year. Among these, coronary heart disease almost accounts 50% deaths associated with CVD, which causes the blockage of the coronary arteries that supplies blood to the heart. Nowadays, the cardiac tissue engineering have become a promising solution to overcome the drawbacks associated with current therapies. Further, the scaffold used in cardiac tissue engineering must possess thromboresistant and anticoagulant nature to serve as a plausible candidate for cardiovascular applications. In this present investigation, a novel nanocomposite based on polyurethane (PU) and carotino oil was fabricated using electrospinning. Scanning electron microscopy images indicated that the nanocomposites have smaller fiber diameter (702 ± 130 nm) compared to the pristine PU (969 ± 217 nm). The Fourier transform infrared spectroscopy analysis confirmed the interaction between the carotino oil and PU by the formation of hydrogen bond and shifting of CH peak. The contact angle of electrospun PU/carotino oil was found to be 119°, which was increased compared to pristine PU (86°) indicating the hydrophobic nature of developed nanocomposites. Moreover, the surface roughness and thermal stability were found to be enhanced due to the presence of carotino oil in the PU matrix indicated in atomic force microscopy and thermogravimetric analysis. The enhanced surface roughness of nanocomposites resulted in delayed activation of the blood clot as revealed in activated partial thromboplastin time and prothrombin time assay. Moreover, the hemolytic index of fabricated nanocomposites was found to very low of about 1.33% compared to pristine PU (2.73%), suggesting non‐hemolytic nature and also better blood compatibility. So, the developed PU/carotino nanocomposites having desirable characteristics like better physicochemical and blood compatibility may render appropriate potentials for raw materials of cardiac tissue engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45691.

Anatomy and physiology of phrenic afferent neurons.

Large-diameter myelinated phrenic afferents discharge in phase with diaphragm contraction, and smaller diameter fibers discharge across the respiratory cycle. In this article, we review the phrenic afferent literature and highlight areas in need of further study. We conclude that 1) activation of both myelinated and nonmyelinated phrenic sensory afferents can influence respiratory motor output on a breath-by-breath basis; 2) the relative impact of phrenic afferents substantially increases with diaphragm work and fatigue; 3) activation of phrenic afferents has a powerful impact on sympathetic motor outflow, and 4) phrenic afferents contribute to diaphragm somatosensation and the conscious perception of breathing. Much remains to be learned regarding the spinal and supraspinal distribution and synaptic contacts of myelinated and nonmyelinated phrenic afferents. Similarly, very little is known regarding the potential role of phrenic afferent neurons in triggering or modulating expression of respiratory neuroplasticity.

Mussel Inspired Polynorepinephrine Functionalized Electrospun Polycaprolactone Microfibers for Muscle Regeneration

Electrospun scaffolds with excellent mechanical properties, high specific surface area and a commendable porous network are widely used in tissue engineering. Improving the hydrophilicity and cell adhesion of hydrophobic substrates is the key point to enhance the effectiveness of electrospun scaffolds. In this study, polycaprolactone (PCL) fibrous membranes with appropriate diameter were selected and coated by mussel-inspired poly norepinephrine (pNE). And norepinephrine is a catecholamine functioning as a hormone and neurotransmitter in the human brain. The membrane with smaller diameter fibers, a relative larger specific surface area and the suitable pNE functionalization provided more suitable microenvironment for cell adhesion and proliferation both in vitro and in vivo. The regenerated muscle layer can be integrated well with fibrous membranes and surrounding tissues at the impaired site and thus the mechanical strength reached the value of native tissue. The underlying molecular mechanism is mediated via inhibiting myostatin expression by PI3K/AKT/mTOR hypertrophy pathway. The properly functionalized fibrous membranes hold the potential for repairing muscle injuries. Our current work also provides an insight for rational design and development of better tissue engineering materials for skeletal muscle regeneration.

Effect of fibre diameter on fabrication of modified PAN nanofibrous membranes and catalytic performance of their Fe complexes for dye degradation

Polyacrylonitrile nanofibrous membranes ( n-PAN-FMs) with different fibre diameters were prepared using electrospinning process and modified with hydroxylamine hydrochloride. The modified n-PAN-FMs were further coordinated with Fe3+ ions to produce a series of the modified n-PAN-FMs Fe complexes, and the catalytic activity of which was investigated as the heterogeneous Fenton catalyst for the dye degradation. The effect of fibre diameter on modification and coordination of n-PAN-FMs as well as the catalytic activity of the resulting complexes was also examined. The results indicated that increasing fibre diameter proportionally enhanced the amidoximation degree of n-PAN-FMs. The modified n-PAN-FMs consisting of small fibre diameters easily coordinated with Fe3+ ions, especially at high temperature to form the complex with high Fe content at the same conditions. Besides, these complexes exhibited the catalytic performance for the dye degradation in the dark and under visible irradiation at a wide pH range. The complex with middle fibre diameter showed a stronger catalytic performance than the complexes with much bigger or smaller fibre diameter due mainly to its large specific surface area and the proper size pores among fibres as well as better water affinity.

Fabrication of Polyurethane/Rare Earth Nanofiber Composite by Electrospinning and Its VOCs Reduction Characteristics

Volatile organic compounds (VOCs) are a source of air pollution and are harmful to both human health and the environment. In this study, we fabricated polyurethane/rare earth (PU/RE) composite nanofibrous membranes via electrospinning with the aim of removing VOCs from air. The morphological structure of PU/RE nanofibrous mats were investigated using FE-SEM, EDX, and XRD experimental analyses. A certain amount of RE (up to 50 wt% compared to PU pellets) particles could be loaded on/into PU fibers. The PU nanofiber containing 50 wt% RE powder had the smallest fiber diameter of 356 nm; it also showed the highest VOCs absorption capacity compared with other composite membranes, having an absorption capacity about 3 times greater than pure PU nanofibers. In addition, all of the PU/RE nanofibrous membranes readily absorbed styrene the most, followed by xylene, toluene, benzene and chloroform. Therefore, the PU/RE nanofibrous membrane can play an important role in removing VOCs from the air, and its development prospects are impressive because they are emerging materials.

Fiber size effects on mechanical behaviours of SiC fibres-reinforced Ti3AlC2 matrix composites

In this study, different diameters SiC fibres-reinforced Ti3AlC2 matrix composites were fabricated via hot-pressing. The mechanical behaviours of the obtained composites were evaluated at room temperature by using 4-point bending testing. The results show that the flexural strength and damage tolerance are significantly higher for smaller diameter fibres-containing composites than for large diameter fibres-containing ones. In addition, the mechanical properties of the composites were improved when smaller diameter fibres partially replaced large diameter fibres and the improvement increased with increase of the amount of smaller diameter fibre. Furthermore, the fracture fashion of the composites depended on fibre diameters used.

Fiber characteristics of pork muscle exhibiting different levels of drip loss.

The present study aimed to investigate the fiber characteristics of pork muscle exhibiting different levels of drip loss during storage. The samples were taken from Longissimus dorsi muscle to evaluate drip loss (n=100). Fifteen muscles per group (low and high drip loss) were selected to evaluate the histological characteristics at 0 and 72h of storage time. The statistical analysis revealed that a high drip loss group had greater endomysium thickness than a low drip loss group at 0h of storage time (P<0.05). There were no significant differences in total number of fibers, fiber diameter, fiber area and perimysium thickness at 0h of storage time (P>0.05). At 72h of storage time, a high drip loss was evident in higher total number of fibers (P<0.01), but smaller fiber diameter (P<0.05), fiber area (P<0.01) and endomysium thickness (P<0.01) than a low drip loss group. There was no significant difference in perimysium thickness (P>0.05). In conclusion, drip loss might be affected by muscle structural characteristics during storage.