Fiber Rods Research Articles

Janus rod-like micromotors to promote the tumor accumulation and cell internalization of therapeutic agents

The navigation of drug-loaded nanocarriers is confronted with series of physiological and pathological barriers in blood circulation, tissue penetration and cell internalization. In the current study, self-propelled micromotors of fiber rods are proposed to address the transportation barriers of chemotherapeutic drugs. Fiber rods with distinct Janus structure are prepared by side-by-side electrospinning, and urease and folate are conjugated on the respective sides of Janus rods (JRs) as power source and targeting ligands of Janus micromotors (JMs). The grafting density of urease determines the motion velocity and trajectory of JMs, and the high motion velocity and large mean-square displacement are detected in both phosphate-buffered saline and simulated extracellular matrices of tumor tissues. Despite no interference with the uptake pathway, the self-propelled motion promotes the folate-mediated cell internalization of JMs and maximizes the toxicities and apoptosis rate of tumor cells. The self-propulsion force from one side of JMs enhances the lateral drift and extravasation across blood vessel walls, increasing their accumulation in tumor tissues by around 2 folds and, doxorubicin accumulation, by around 2.6 folds. The treatment with JMs remarkably inhibits the tumor growth, prolongs the animal survival rate and induces strong tumor necrosis without obvious histopathological and hematological abnormalities to normal tissues. Thus, this study demonstrates a feasible strategy in combating the navigation barriers of blood vessel extravasation, tumor tissue diffusion and cell capture, effectively promoting the treatment efficacy and alleviating side effects of chemotherapeutic agents.

Improvement of punching shear strength of reinforced lightweight concrete flat slab using different strengthening techniques

This paper investigates the strengthening techniques of lightweight concrete (LWC) flat slabs vulnerable to punching shear failure. Thirteen reinforced LWC flat slab specimens were experimentally tested. The main investigated parameters were the type of shear reinforcement (steel bars, high strength bolts, or glass fiber reinforced polymers (GFRP) rods), spacing, shear reinforcement configuration around the column and the fixation method of shear reinforcement. The test results showed that using radial shear reinforcement with spacing of (d/2) resulted in the most efficient strengthening technique. The punching shear capacities were improved by 77%, 61% and 54% by using steel bars, glass fiber rods and high strength bolts, respectively, compared to the reference specimen. Moreover, using high strength steel bolts fixed to the slabs with steel plates showed the highest ductility compared with the other strengthening techniques Also, the failure mode converted from being brittle shear failure to flexural-shear mode. Non-linear finite element analysis (NLFEA) was carried out for the numerical verification. The analysis adequately reflected the trend of experimental results. Finally, the experimental test results were evaluated with code equations. The evaluation showed that the ACI 318 code underestimated the punching shear capacity of the tested specimens. On the other hand, Euro Code showed good prediction of the punching shear strength of the tested slabs.

Composite PEEK/carbon fiber rods in the treatment for bone tumors of the cervical spine: a case series

Radiotherapy (RT) is frequently applied as an adjuvant therapy during spinal tumors treatment. Metallic implants can interfere with RT planning and execution, as it is known that metallic implants produce a backscattering effect that can limit RT accuracy and their presence can be associated with unwanted dose increase. PEEK/carbon fiber implants are designed to reduce these problems but their application in the cervical spine is limited, due to the reduced number and types of implants, the screw dimensions and the absence of lateral mass screws. We propose a hybrid system made of carbon rods and screws coupled with subliminal polyester bands with titanium clamps. We designed this hybrid construct to enclose the cervical region in the area of instrumentation without limiting the application of postoperative radiotherapy. Six patients in which the hybrid hardware was implanted were retrospectively examined. Data on demographics, intraoperative and postoperative events, tumor details and staging and cervical alignment were collected pre- and postoperatively. No intraoperative complications occurred. En bloc resection was performed in two patients, while the remaining four received an intralesional resection. Three out of six patients received postoperative RT, without any alteration in its planning and administration. Hybrid implants made of composite PEEK/carbon fiber screws and rods and sublaminar bands are a helpful solution for spinal reconstruction in the cervical and cervico-thoracic regions after spine tumor surgery. The implants do not produce artifacts at postoperative images, easing the planning and execution of postoperative radiotherapy.

Study on Properties Prediction and Braiding Optimization of Axial Braided Carbon/Carbon Composite.

It is well established that the microstructure has significant effects on the properties of axial braided C/C composites. In this study, a method coupling the homogenization method and finite element method (FEM) was proposed to predict the relationship between the microstructure characteristics and macroscopic properties. Based on the representative volume element (RVE) model, the periodic displacement boundary condition was introduced to predict the equivalent elastic properties of the RVE and component of C/C composite material, and the coefficient of thermal expansion (CTE) of the material was predicted by the energy prediction method. The predicted results were in good agreement with experimental results. By predicting the thermal and mechanical properties of the materials with different braiding spacing and fiber rod diameter, the variation of the properties with braiding spacing and fiber rod diameter was obtained. The research methods and results in this paper could provide important references for the optimization and rational application of composite materials.

Hierarchically targetable fiber rods decorated with dual targeting ligands and detachable zwitterionic coronas

The shapes of drug carriers have significant effects on the drug's blood circulation lifetime and tumor accumulation levels. In this study, nonspherical drug carriers of fiber rods are enhanced with hierarchically targeting capabilities to achieve long circulation in blood, on-demand recovery of cell targeting ligands in tumor tissues and dual ligands-mediated cellular uptake. Zwitterionic polymers are conjugated on fiber rods via acid-labile linkers as stealth coronas to reduce the capture by macrophages and shield the targeting ligands. Compared with commonly used poly(ethylene glycol), the zwitterionic grafts show significantly higher inhibition of protein adsorption and lower internalization by macrophages, leading to around 2 folds longer blood circulation and over 2.5 folds higher drug accumulation in tumors than pristine fiber rods. To address the conflicts between blood circulation and cellular uptake, the zwitterionic coronas are efficiently removed in the slightly acidic tumor microenvironment. The exposure of targeting ligands could activate the internalization by tumor cells, resulting in higher cytotoxicity and tumor accumulation than those with stable linkers. Fiber rods are grafted with dual ligands of folate and biotin, and the optimal ligand densities and ratios are determined to maximize the tumor cell uptake. Compared with other treatment, fiber rods with decorated zwitterionic coronas and acid-liable exposure of dual targeting ligands enhance the suppression of tumor growth, prolong animal survival, and cause less lung metastasis. The development of fiber rods with hierarchically targeting capabilities shows great potential in improving the blood circulation, tumor accumulation and cellular uptake, and eventually promoting therapeutic efficacy. Statement of SignificanceThe targeted delivery of chemotherapeutic agents will encounter a series of biological and pathological barriers. In this study, fiber rods were empowered with hierarchically targeting capabilities to resolve the conflict between blood circulation and cellular uptake. This strategy has shown several advantages over the existing methods. Firstly, zwitterionic polymers were used as blood circulation ligands, and concrete evidence was provided via head-to-head comparison with commonly used poly(ethylene glycol) ligands in the macrophage uptake and in vivo tissue distribution. Secondly, the depletion of circulation ligands and on-demand exposure of targeting ligands in tumor tissues showed crucial effects on the uptake by tumor cells. Thirdly, the densities and ratios of the dual targeting ligands were initially determined for a maximal cellular internalization.

A novel method of output metering with dynamometer card for SRPS under fault conditions

Remote monitoring of sucker rod pumping system (SRPS) based on polished rod dynamometer cards (DC) is an effective means to reduce the operating costs and realize the real-time control. Nevertheless, how to obtain the working process and the production rate of SRPS from polished rod DC is always a puzzle because of complex down-hole motions. The typical solution for this problem is deriving the pump DC via the wave equation to achieve the effective stroke of plunger. But some key parameters involved in this approach such as valve leakage and the fill factor are difficult to determine accurately, especially under fault conditions, which may influence the accuracy of output metering.In order to address this tough issue, in this paper, a novel method of output metering with DC is proposed based on quantitative analysis of fault. The method consists of two parts, the first part is an approach to simulate the working process of SRPS under fault conditions, specifically it's an improved simulation model characterized by a set of fault parameters, which is presented through analyzing the mechanisms of sucker rod pumps at normal and several faulty scenarios. And the second part is a method implemented by genetic optimization algorithm to determine the fault parameters set of the actual SRPS.Using parameters of typical well, the analysis of effects of faults on SRPS is carried out. The simulation results show that valves leakage reduces the flow rate of liquid significantly in the period of effective stroke, which leads to the distortion of output metering results of effective stroke method. Compared with single faults, coupling faults aggravate the production reduction of SRPS. Furthermore, when the well fluid contains gas, the impact of traveling valve leakage on the reduction of production is greater than that of standing valve leakage, but the consequence is opposite when formation energy is insufficient. Besides, the carbon fiber rod and fiberglass rod SRPS are more sensitive to valve leakage, while the steel rod and wire rope SRPS are more sensitive to the condition of insufficient liquid supply.Eventually, the proposed method is verified experimentally through the productive parameters and measured DC of actual wells collected from an oilfield. The obtained results demonstrate the effectiveness of the proposed method for output metering and fault diagnosis as well.

Спосіб виготовлення труб з полімерних композиційних матеріалів для конструкцій літальних апаратів

The frame power structures are widely applied when designing aircraft, in which composite rod elements are used to reduce the mass and size characteristics. To solve the problem of manufacturing rod elements from polymer composite materials, we developed a technology for the manufacture of carbon fiber pipes using an existing machine for winding carbon fiber, which provides the necessary strength and rigidity mainly in the longitudinal direction.When calculating the rod elements, all the loads that will affect the structure as well as the coefficient of thermal expansion should be taken into account. To achieve the required physical, mechanical, and thermophysical characteristics, the optimal scheme of reinforcement is the scheme with a quasi-longitudinal direction of the fibers. We developed the method of manufacturing based on the technology allowing us to obtain a reinforcement scheme with fiber orientation in the quasi-longitudinal direction with a reinforcement angle of about 1° by a combined method of layer-by-layer winding of carbon fiber. As a result of technological testing, we obtained samples of carbon fiber rod elements, which were used to confirm the calculated characteristics. To confirm the physico-mechanical and thermophysical characteristics, we determined the assessment of limit of strength and modulus of elasticity in bending, the limit of strength and modulus of elasticity in torsion, the limit of strength and modulus of elasticity in compression, and the coefficient of thermal expansion. The obtained characteristics of the dependences of the elasticity modulus of the pipe prototype material at the fibers’ orientation angle correlate with theoretical calculations. The presented method has the patent UA 128613 U.

Machine for winding a rib onto glass fiber rod

The article presents a new machine for winding a rib onto glass fiber rod. The machine allows increasing the productivity of the production line, decreasing the amount of waste from production and decreasing the noise and vibration. Article shows key parameters of the machine. A patent protects the machine.

Composite peek/carbon fiber pre-shaped rods and sublaminar bands for posterior stabilization of cervico-thoracic junction: A novel technique

The combination of surgery plus radiotherapy is a valid treatment option when en bloc resection with wide margins is not feasible. The aim of this paper is to show a novel technique for fixation of cervico-thoracic junction with carbon fiber reinforced peek pre-shaped rods with sublaminar bands in order to guarantee cervical spine stability and particle therapy efficacy.A 42 years-old man with a Sclerosing Epithelioid Fibrosarcoma (SEF) arising from C7, involving the right latero-cervical region from C5 to the apex of the right lung, underwent an en bloc resection with a double approach (anterior plus posterior). Fixation of cervical spine was achieved with composite PEEK/carbon fiber rods connected to C4 and T2 laminae with sublaminar bands. After surgery, the patient received 9 cycles of chemotherapy (cisplatin, etoposide and adriamycin) and proton therapy.At 2 years follow-up, no local recurrence was detected with implant stability demonstrating no mechanical failure.The main issues related to this case were: planning en bloc resection able to achieve an Enneking appropriate margin; incorporate in the decision making process the functional loss related to the sacrifice of neurological structures infiltrated by the tumor; establish a therapeutic strategy that included, in addition to surgery, adjuvant chemotherapy and radiotherapy for improving local and systemic control; stabilize with implants that do not interfere with accelerated particle radiotherapy.

Fatigue life evaluation of composite wing spar cap materials

AbstractAn effective method for evaluating the fatigue strength of thick unidirectional composite laminates of wing spar caps has been presented here. A typical width-tapered bending specimen has been developed for a four-point loading set up. Static and fatigue loading was performed at a load ratio R = ‒1. The complex stress state has been investigated numerically by finite element analysis. Finally, the concept is proven experimentally on specimens made of pultruded fibre rods. The fatigue behavior of the continuously tapered width by water jet cutting has been compared to discrete tapering via rod-drop. The new method enables a screening of material fatigue behavior caused by normal and shear loading.

All-Fiber Highly Sensitive Bragg Grating Bend Sensor.

In this paper, we demonstrated a novel, all-fiber highly sensitive bend sensor based on a four-core fiber rod with a diameter of 2.1 mm. We observed a high resolution of the sensor at a level of 3.6 × 10−3 m−1. Such a sensor design can be used in harsh environments due to the relatively small size and all-fiber configuration, containing no adhesive, nor welded joints.

Effectiveness of Reinforcing Bent Non-Uniform Pre-Stressed Glulam Beams with Basalt Fibre Reinforced Polymers Rods.

The article presents the testing designating the impact of structural non-uniformity on the effectiveness of reinforcing bent wooden beams reinforced with basalt fibre (BFRP—Basalt Fibre Reinforced Polymers) rods. The obtained results demonstrate a positive impact of the strengthening in improving the bearing capacity and rigidness of the wooden beams. The article presents the impact of selected physical and chemical properties of wooden elements on the achieved strengthening reliability, increase in bearing capacity and the estimation of the reduction of deflections and stresses of bent beams, made from various wood quality classes and reinforced using BFRP rods. The conducted testing featured an analysis of the ability of using lower quality class lumber to strengthen the beams with pre-stressed basalt fibre rods. This solution allows for reducing the cross-section or lower the class of used wood with simultaneous maintenance of comparable rigidity and bending strength of beams, as in the non-strengthened beams.

Processing of Nickel-Copper Coated Carbon Fibre Rods Reinforced Al6082/4% Al<sub>2</sub>O<sub>3</sub>/2%Gr Matrix Composites

Aluminum metal matrix with carbon fibre reinforcement composites are potential materials for automotive, aerospace and electronics industries. The interaction between Al matrix and carbon fibre reinforcement, plays vibrant role to decide the properties of the Metal Matrix Composites (MMC’s). However, interaction between Al alloy matrix and carbon fibre is forming an Aluminum Carbide (Al4C3) at higher temperature (>650°C). This consequence degrades the mechanical properties and promotes corrosion. To overcome corrosion problem and improve the composite properties, metallic coating on carbon rod is very vital. In the present study, aluminum metal matrix composites (Al6082/4%Al2O3+2%Gr) were developed with coated carbon fibre rod using stir casting process. Carbon fibre rods of 3 mm diameter is coated with nickel by electro less process and then copper coating done by electrolytic process. The bonding between matrix and reinforcement was observed in SEM and EDAX analysis. The results indicates the absent of Al4C3 formation.

Amplification of a radially polarized beam in a thermally guiding ytterbium-doped fiber rod

Amplification of a radially polarized beam from an Yb:YAG seed laser at 1030 nm in a very-large-core triple-clad ytterbium-doped fiber configured as a thermally guiding fiber rod amplifier is demonstrated. The amplifier yielded a maximum output power of 10.7 W (limited by available pump power) with corresponding single-pass gain of 6.4 dB, while the radial polarization purity was maintained over the full range of pump power with a measured polarization extinction ratio of 100:1. The amplified output beam displayed the characteristic donut-shaped intensity profile with negligible beam distortion as evidenced by a measured beam propagation factor (M2) of 2.1 ± 0.1. A simplified model for propagation of a radially polarized beam in a thermally guided fiber rod is developed to provide insight into the underlying design principles and to establish a strategy for scaling output power. The power scaling limitations of this approach are considered.

Crashworthiness of cardboard panels reinforced with braided glass fiber rods for vehicle side impact protection

This paper investigates the quasi-static compression properties of cardboard panels reinforced with braided glass fiber rods manufactured using a tubular braiding method. Compression tests are performed on single- and two-layer panels reinforced with varying number of rods and panel layer orientation. The crushing results of single-layer panels show more progressive crushing behavior than those of two-layer panels for different number of rods. In two-layer panels, certain rods are inclined from the direction of applied load due to deformation of the surrounding cardboard, resulting in reduced specific energy absorption compared with single-layer panels. Moreover, panels consisting of two layers of cardboard oriented in the same direction perform better than when the layers are off-set 90° where cardboard shifting is more pronounced. The role of cardboard is to constrain the rods from excessive splaying, causing greater levels of fiber fragmentation which consumes more energy compared with rods without cardboard.

One-Step Preparation of Poly(Lactide-Co-Glycolide) Fiber Rods Embedding with Luminescent Materials as a Drug Delivery System via Electrospray

One-Step Preparation of Poly(Lactide-Co-Glycolide) Fiber Rods Embedding with Luminescent Materials as a Drug Delivery System via Electrospray

A study on the energy absorption capacity of braided rod composites

Abstract Composite materials are becoming popular among automobile manufacturers because of their high strength, light weight, and controlled crushing mechanisms. Many composite structures have been designed and developed as energy absorption components in automobiles until now. Following the trend, in this study UD and braided UD glass fiber rods were manufactured as an energy absorption component for the automotive industry and their energy absorption capability was measured by quasi-static compression testing. In order to fully understand the crushing mechanisms, the effect of braiding layers, braiding technique, taper angle, single and multiple rods and their separation on the energy absorption capability was investigated. Braided UD rods absorbed more energy compared to the MFW (multifilament wounded) rods, while tapering one side of the rod greatly influenced the crushing distance, yield point, and load bearing capabilities. Additionally, the mean load of three BR-1L rods was almost three times higher than that of a single rod however, it was influenced by varying the distance among them. The aim of this research was to collect more data about the crashworthiness of composite rods under different parameters and to gain a better understanding for future research work.

Effect of Repeated Sterilization by Different Methods on Strength of Carbon Fiber Rods Used in External Fixator Systems.

We aimed to study the effects of repeated sterilization, using different methods, on the carbon fiber rods of external fixator systems. We used a randomized set of 44 unused, unsterilized, and identical carbon fiber rods (11 × 200 mm), randomly assigned to 2 groups: unsterilized (4 rods) and sterilized (40 rods). The sterilized rods were divided into 2 groups, those sterilized in an autoclave and those sterilized using hydrogen peroxide. These were further divided into 5 subgroups based on the number of sterilization repetition to which the fibers were subjected (25, 50, 75, 100, and 200). A bending test was conducted to measure the maximum bending force, maximum deflection, flexural strength, maximum bending moment and bending rigidity. We also measured the surface roughness of the rods. An increase in the number of sterilization repetition led to a decrease in maximum bending force, maximum bending moment, flexural strength, and bending rigidity, but increased maximum deflection and surface roughness (P < 0.01). The effect of the number of sterilization repetition was more prominent in the hydrogen peroxide group. This study revealed that the sterilization method and number of sterilization repetition influence the strength of the carbon fiber rods. Increasing the number of sterilization repetition degrades the strength and roughness of the rods.

Analysis of the natural fiber reinforced polymer: composite fiber rods (FRPCY)

Fiber reinforced polymer composites (FRPC) can be used in new or repaired reinforced concrete structures. Fiber reinforced polymer composite yarn (FRPCY) can be formed as rods of different diameter and length to be used in the formation of concrete structures due to their superior light weight, corrosion resistance, the lack of material ductility and energy absorbing capabilities. The formation of these FRPCY rods using natural fibers yarns is tried in this work. Due to the variation of the fiber volume fraction of the yarn along its length, it will directly reflect on the fiber volume fraction of the formed composite. In this work, the relation between the yarn volume fraction and the composite fiber volume fraction were studied, taken into consideration its variation along the yarn length. The formation of these rods using flax yarns is tried in this work and their mechanical properties are investigated.

A soil moisture estimation method using actively heated fiber Bragg grating sensors

Although many methods of soil moisture measurement exist, there remains a lack of soil moisture sensor with small volume, high precision, excellent real-time performance and distributed monitoring capability. In this paper, a fiber Bragg grating (FBG)-based carbon fiber heated sensor (CFHS) that can overcome the deficiencies in soil moisture movement is proposed. The CFHS consists of a carbon fiber rod with a diameter of 5 mm, quasi-distributed FBG sensors on an optical fiber, a coating, two binding posts, and two electric cables. Laboratory calibration tests have been conducted to establish an empirical piece-wise relationship between the temperature characteristic value and soil moisture for sand, silt and clay. A laboratory validation test under normal gravity and a centrifuge test under overweight conditions, have been performed to verify the feasibility of this technique for soil moisture monitoring. The test results show that the CFHS can (i) accurately record soil moisture under normal gravitational and overweight conditions and (ii) track the evolution of capillary zones, and the generation and migration of moisture transition zones under centrifuge acceleration. During a response period of 5 min, the accuracy is 0.033 m3/m3 under 1 g condition, and 0.047 m3/m3 under overweight condition. With the advantages of small sensor size, low disturbance of soil mass and wide adaptability in physical model tests, the proposed method can achieve distributed soil moisture measurement at different scales and with high efficiency.