Silicon Rods Research Articles

Factors associated with pediatric silicone rod frontalis sling exposure or infection: single-institution experience of 193 eyelids.

To determine the pre-operative, peri-operative, or post-operative risk factors that contribute to pediatric frontalis sling infection or exposure. Retrospective study of 193 eyelids that underwent silicone-rod frontalis sling surgery at a single institution between 2014 and 2019. A total of 222 eyelids were originally identified. Of the 222 eyelids that underwent frontalis sling surgery, 193 (86.9%) received silicone-rod slings (SRS), 24 (10.8%) received autologous fascia lata sling (AFS), and 5 (2.3%) received Gore-Tex slings (GS). The 193 eyelids that received SRS met inclusion criteria and underwent further statistical analysis. Patients with SRS who did not receive intra-operative antibiotics had a higher risk of infection or exposure compared to patients with SRS that did receive intraoperative antibiotics (P = 0.03). There was no association between SRS exposure and the other studied risk factors (all P-values > 0.41). Intraoperative antibiotics should be considered in silicone-rod frontalis suspension surgery, as it associated with a decreased risk of exposure or infection.

Crystal surface heat transfer during the growth of 300mm monocrystalline silicon by the Czochralski process

This paper investigated the lower heat transfer efficiency of ingot after increasing the size of Czochralski monocrystalline silicon. To improve the heat transfer efficiency, industrial Czochralski monocrystalline furnaces use water-cooling jackets to enhance crystal heat transfer. Through two-dimensional modeling, radiative heat transfer between monocrystalline silicon and the water-cooling jacket was investigated. The results showed that the effective radiation on the crystal surface decreased, then increased, and then decreased again. Numerical simulations showed that the maximum effective radiation on the surface was greater than 60 000 W/m2, which represents a significant increase in the heat flow density compared with the radiation of the crystal without using water cooling. According to the angle factor definition, a model of the radiative heat transfer angle factor between the water-cooling jacket and silicon rod was established. The dynamic correlation equation between the radiation angle factor and geometrical parameter of the hot zone, solidification rate, and solidification time was derived. Finally, a water-cooling jacket suitable for growing large monocrystalline silicon rod was designed according to the model, which improved the growth efficiency of the crystals. The results of the study are of great significance for optimizing water-cooling jackets.

Silicone sling surgery for congenital ptosis: Tarsal tunnel technique.

This was a prospective, interventional, comparative study conducted on patients with congenital simple severe ptosis. A novel method of silicone rod fixation to the tarsus (tarsal tunnel technique, group 1) was done compared with a conventional technique of silicone rod fixation (suture fixation technique, group 2) in frontalis suspension surgery. A total of 30 patients were randomized into two groups of 15 patients each. Postoperatively, MRD1, vertical palpebral aperture, and eyelid fold height were comparable in both groups till the last follow-up with stability in eyelid position. Patient satisfaction scores showed similar results with good-fair satisfaction grading in 13 patients in group 1 and 11 patients in group 2 at 6 months follow-up. No significant complications occurred in either group. Tarsal tunnel fixation of silicone rods is a novel method in sling surgery with optimal cosmetic and function outcomes. Further long-term studies are needed to validate the results of the technique.

PMMA-induced biofilm promotes Schwann cells migration and proliferation mediated by EGF/Tnc/FN1 to improve sciatic nerve defect

ObjectiveThe purpose of this study is to investigate the role of PMMA-induced biofilm in nerve regeneration compared with silicone-induced biofilm involved in the mechanism. MethodsPMMA or silicon rods were placed next to the sciatic nerve to induce a biological membrane which was assayed by PCR, Western blot, immunohistochemistry, immunofluorescence and proteomics. A 10 mm sciatic nerve gaps were repaired with the autologous nerve wrapped in an induced biological membrane. The repair effects were observed through general observation, functional evaluation of nerve regeneration, ultrasound examination, neural electrophysiology, the wet weight ratio of bilateral pretibial muscle and histological evaluation. Cell proliferation and migration of Schwann cells co-cultured with EGF-treated fibroblasts combined with siRNA were investigated. ResultsThe results indicated that expression of GDNF, NGF and VEGF along with neovascularization was similar in the silicone and PMMA group and as the highest at 6 weeks after operation. Nerve injury repair mediated by toluidine blue and S100β/NF200 expression, the sensory and motor function evaluation, ultrasound, target organ muscle wet-weight ratio, percentage of collagen fiber, electromyography and histochemical staining were not different between the two groups and better than blank group. EGF-treated fibroblasts promoted proliferation and migration may be Tnc expression dependently. ConclusionOur study suggested that PMMA similar to silicon induced biofilm may promote autogenous nerve transplantation to repair nerve defects through EGF/Tnc/FN1 to increase Schwann cells proliferation and migration.

Ultra-sensitive Two-dimensional Photonic Crystal Biosensor for Oral Cancerous Cell Detection

Background & Objectives: Over the past two decades, biophotonic sensors based on two-dimensional (2D) photonic crystals (PhCs) have garnered significant attention in cancer diagnosis. This technology has become a crucial tool in early cancer detection and treatment response monitoring due to its ability to detect minute changes in biomarker concentrations and molecular interactions. The development of these sensors through advanced nano and microfabrication techniques has significantly improved diagnostic accuracy and speed, promising substantial enhancements in therapeutic outcomes for cancer patients. Materials & Methods: A biosensor based on a 2D PhC was designed and simulated for the detection of oral cancer cells in a sample. The biosensor, structured with silicon rods in air using the Finite-Difference Time-Domain tool, utilizes five rods as an analyte for detecting normal and cancerous cells, thereby evaluating the sensor’s performance. Results: The variation in the transmission spectrum was studied to detect the presence of malignant cells in the test sample. The sensor’s structural parameters were carefully adjusted to enhance its sensitivity, a crucial factor in the accurate detection of cancerous cells. Two critical parameters, Q-factor and sensitivity, were derived from the results. The sensor achieved a sensitivity of 1148 nm/RIU with a Q-factor of 193. Conclusion: The designed biosensor demonstrates superior accuracy and sensitivity in identifying both malignant and normal cells in the test sample, making it suitable for real- time deployment in point-of-care applications.

A sustainable mineral process for silicon and quartz recovery from quartz crucible waste ash via electrical separation

Driven by the explosive development of the photovoltaic (PV) industry, the treatment of the quartz crucible waste ash (QCWA) from monocrystalline silicon rod production must be considered to combat the shortage of silicon materials and promote sustainable development. In particular, the loss of grade 4 N high-purity silicon in QCWA is a frustrating fact for the silicon supply chain. In this work, an electrical separation process is proposed for the recovery of silicon and quartz from QCWA to realize waste resource reutilization. The charging processes and forces in the feed QCWA are first analyzed. Then, the electric field distribution during electrical separation is simulated to clarify the movement models of silicon and quartz particles and formulate reasonable electrical separation parameters. After systematic theoretical analysis, calculation, and simulation, electrical separation experiments were conducted. The results prove that the content of silicon in the concentrate and the corresponding content of quartz in the tailing respectively exceeded 93 % and 61 % under a particle size of 80 ∼ 120 mesh, a voltage of 40 kV, and a roll speed of 75 r/min. This work demonstrates that electrical separation is a sustainable process that could be recommended for silicon and quartz recovery from QCWA.

Design of All-Optical D Flip Flop Memory Unit Based on Photonic Crystal.

This paper proposes a unique configuration for an all-optical D Flip Flop (D-FF) utilizing a quasi-square ring resonator (RR) and T-Splitter, as well as NOT and OR logic gates within a 2-dimensional square lattice photonic crystal (PC) structure. The components realizing the all-optical D-FF comprise of optical waveguides in a 2D square lattice PC of 45 × 23 silicon (Si) rods in a silica (SiO2) substrate. The utilization of these specific materials has facilitated the fabrication process of the design, diverging from alternative approaches that employ an air substrate, a method inherently unattainable in fabrication. The configuration underwent examination and simulation utilizing both plane-wave expansion (PWE) and finite-difference time-domain (FDTD) methodologies. The simulation outcomes demonstrate that the designed waveguides and RR effectively execute the operational principles of the D-FF by guiding light as intended. The suggested configuration holds promise as a logic block within all-optical arithmetic logic units (ALUs) designed for digital computing optical circuits. The design underwent optimization for operation within the C-band spectrum, particularly at 1550 nm. The outcomes reveal a distinct differentiation between logic states '1' and '0', enhancing robust decision-making on the receiver side and minimizing logic errors in the photonic decision circuit. The D-FF displays a contrast ratio (CR) of 4.77 dB, a stabilization time of 0.66 psec, and a footprint of 21 μm × 12 μm.

Energy saving of 42-pair Siemens reactor with different layouts for polysilicon production: Three rings and four rings

This study devolped two physical models to represent two annular silicon rod distribution patterns in 42 pairs of furnaces: a three-ring layout and a four-ring layout. It investigated the impact of different silicon rod radii and distributions on flow field, temperature field, and energy consumption in Siemens polycrystalline silicon furnaces, to reduce the high energy during polysilicon production. It was revaled that the energy consumption increases with the radius of the silicon rod under two layouts, and this change is jointly affected by the flow field and temperature field inside the furnace. Additionally, it was observed that radiation energy consumption concerning the inner-ring silicon rod within the reduction furnace exhibited an initial increase followed by a subsequent decrease as the silicon rod radius grew. In contrast, the radiation energy consumption of the outer-ring silicon rod displayed a positive correlation with the silicon rod's radius. These findings led to the proposal of an energy consumption reduction strategy for large Siemens reduction furnaces, advocating the adoption of a three-ring layout to minimize overall energy consumption in polycrystalline silicon reduction furnaces effectively.

Implementation of photonic crystal based optical full adder using ring resonators

In this paper, the implementation of an all-optical full adder based on a two-dimensional photonic crystal is proposed. The proposed structure consists of hexagonal lattice of silicon rods embedded in air substrate. To design the proposed optical full adder, three nonlinear ring resonators, some linear waveguides, and some point defects are used. The switching mechanism of the ring resonators is based on nonlinear Kerr effect. The performance of the proposed structure has been analyzed and investigated by using plane wave expansion (PWE) and finite difference time domain (FDTD) methods. The minimum contrast ratio of the structure is 17.02 dB. The response time of the structure is 0.724 ps and can operate at a bit rate of 1.381 Tb/s. The proposed structure is simple, compact, and offers high contrast ratio, fast response time along with high bit rate and therefore can be a promising candidate for high speed data processing, computing, networking, and optical integrated circuits.

Modeling for the Fabrication Process of a ϕ1185 mm C/C Composite Thermal Insulation Tube in an Isothermal Chemical Vapor Infiltration Reactor

The large-size chemical vapor infiltration (CVI) of the carbon/carbon (C/C) composite thermal insulation tube is a key component for drawing large diameter monocrystalline silicon rods. However, the CVI densification process is complex, and the cost of experiment optimization is extremely high. In this article, a multi-physics coupling simulation model was established and validated based on COMSOL Multiphysics v.5.6 software to simulate the fabrication process of an isothermal CVI process for a Φ1185 mm C/C composite thermal insulation tube. The influence of process parameters on densification was explored, and a method of optimization was proposed. Our modeling results revealed that the deposition status in areas of low densification was effectively and significantly enhanced after process optimization. At the monitoring site, the carbon density was no less than 1.08 × 103 kg·m−3, the average density of the composite-material thermal insulation tube improved by 5.7%, and the densification rate increased by 26.5%. This article effectively simulates the CVI process of large-sized C/C composite thermal insulation tubes, providing an important technical reference scheme for the preparation of large-sized C/C composite thermal insulation tubes.

A Comparison of Internal Mandrel Designs for Rotary Draw Bend Forming of Carbon-fibre/Thermoplastic (PA6) Tubular Structures

Carbon fibre reinforced thermoplastic tubular structures can be post-formed into desired curvatures via rotary draw bending (RDB) at elevated temperatures. During this process, a rigid internal mandrel is required to support the walls of the tubes to maintain their ovality and minimise unwanted geometrical distortions. This paper investigates four internal mandrel designs for post-forming carbon fiber reinforced polyamide 6 (CF/PA6) thermoplastic tubes. Mandrel designs include silicone rod, bullet, wire, and coil spring, were evaluated through RDB-forming experiments with [± 60°]4 CF/PA6 tubes formed to 90° bends. The designs were evaluated for their effectiveness on minimising distortions resulted from induced stresses during post-forming by measuring the post-formed tube diameter and extrados strains. The mandrel designs were also evaluated for their usability when integrated into the RDB process. Results from optical measurements and micro-computed tomography showed the spring mandrel outperformed others, producing tubes with the least geometrical distortions and no defects during the forming process. As compared to other designs, the spring mandrel is a reusable unibody design that is easy to assemble and remove from the tubes.

Sling for the sling: a new technique for long-term correction of severe congenital ptosis

IntroductionSevere congenital ptosis poses a complex challenge for oculoplastic surgeons, requiring meticulous surgical intervention to restore eyelid function and improve aesthetic outcomes mainly by using frontalis sling approach. A crucial issue in frontalis sling surgeries is the sustainability of effect.PurposeThis retrospective study reports the outcomes of two surgical techniques for treating severe congenital ptosis in the paediatric age group: Silicon rods ptosis sling and a novel technique involving the use of Silicon rods with green braided polyester (Ethibond) sutures to secure the rods in place “sling for the sling”.MethodsThe medical records of children who underwent frontalis suspension were reviewed in a retrospective fashion. We identified two groups; the first group (20 patients: 35 eyelids) had the traditional frontalis suspension surgery using silicone suspension set, the second group (14 patients: 25 eyelids) was operated using the new “sling for sling” technique. We used the postoperative marginal reflex distance-1 (MRD-1) as the primary outcome measure while the frequency of both wound related complications and recurrence were considered as secondary outcome measures. Post operative data were collected and compared after 1 month, 6 months, 12 months, and 18 months.ResultsPreliminary results indicate promising outcomes for both techniques, with significant improvement in eyelid elevation observed in both groups. However, the novel technique using Silicon rods with Ethibond sutures demonstrated enhanced sustainability, leading to a more durable outcome with significantly less recurrence.ConclusionThis study highlights the potential benefits of the novel technique in treating severe congenital ptosis and introduces an innovative approach to Silicone rods fixation to achieve a long-term corrective effect.

Comparison of Stab Incision and Eyelid Crease Incision Techniques in Children with Revision Frontalis Sling Surgeries Using Silicone Rods.

To compare stab and eyelid crease incision techniques in revision frontalis sling surgeries using silicone rods. This retrospective study involved 52 eyes in 48 consecutive pediatric patients who underwent revision frontalis sling surgery between 2008 and 2019. All primary surgeries were performed by making eyelid crease incisions and suturing of silicone rods onto the tarsal plates. The revision surgeries were performed by either making stab incisions over the eyelid through which to pass the silicone rods (group A), or by refixing the same or a new silicone rod to the tarsal plate (group B). The surgical results were compared. The mean follow-up period was 22.4 months (range, 6-62 months) and the mean age of the patients was 6.1 years (range, 1-16 years). There were 28 female and 20 male patients. Surgical success was achieved in 23 of 28 patients (82.1%) in group A, and 12 of 24 patients (50.0%) in group B. The difference between the groups was statistically significant (p = 0.012). Superficial punctate epithelial defects were detected in six group A patients (21.4%) and seven group B patients (29.1%). In group B, lid hematoma occurred in three patients (12.5%) and entropion occurred in three patients (12.5%). The silicone rods were removed from two eyes, and entropion spontaneously resolved in one eye with close follow-up. Using the stab incision technique increases revision frontalis sling surgery success rates when primary surgeries are performed using eyelid crease incisions and suturing silicone rods to the tarsal plates in children.

Sensing blood components and cancer cells with photonic crystal resonator biosensor

This study presents the design and numerical analysis of an optical biosensor utilizing a photonic crystal resonator to detect alterations in the refractive index in human blood. The biosensor has potential applications for early diagnosis of cancer cells and various viruses. The structure of the biosensor being proposed is comprised of a waveguide and an oval ring resonator, designed via silicon rods in a 2D square lattice. Accurate detection can lead to choosing the best therapeutic approach and accelerate the patient’s recovery, which is possible by utilizing this biosensor. An optimized and compact design of biosensor (10.2 μm × 7.5 μm) with a significant detection resolution and detection limit of 1∗10-4 , a wide range of cell and virus detection from a refractive index of (1.330 ∼ 1.401) proposed to be implemented in real-time medical applications The proposed sensor has a good figure of merit, and high sensitivity values ranging between 650 and 900. Accordingly, an improved sensor with a quality factor as high as 190 is achieved. Through the implementation of the finite-difference time-domain (FDTD) method, the resonator's reaction to perturbations induced by cells and viruses present in the blood is investigated. The exceptional characteristics of biosensor make it one of the potential candidates in the field of biomedical sensing, which exhibits better sensitivity at the Terahertz band, compared to prior works.

Oblique illumination-induced transformation between the FP and the Fano resonances through an all-dielectric metasurface.

We demonstrate the angular dispersive transmission properties of electromagnetic fields with both the Fabry-Pérot (FP) resonances and Fano resonances through an all-dielectric metasurface consisting of a silicon bar array over the silicon dioxide slab. More specifically, when the normal incidence is casting over the metasurface, solely FP resonances will be achieved, and the silicon rod array can be equivalent to another dielectric combining with the silicon dioxide substrate. On the other hand, the Fano resonances will become dominant when the metasurface is under the wide-angular oblique illumination, raising the asymmetry in the silicon bar array to function as toroidal dipoles and electric quadrupoles and thus enable the proposed all-dielectric metasurface to achieve different resonances with the variation of different angular illuminations.

Exceptional points in periodic array of silicon rods

We find numerically the complex eigenvalues in grating composed of infinitely long silicon rods of rectangular cross section and show existence of exceptional points (EPs) in parametric space of structural scales and wave vector along the rods. The EPs have sufficiently small imaginary parts due to their proximity to bound states in the continuum. This enables to trace the resonant frequencies in the transmission around the EP and, accordingly, to identify the EP by bifurcation of the transmission. We present generic coupled mode theory to elucidate this effect. We also show that structural fluctuations of grating preserve EP but obscures their observation because of inhomogeneous broadening of transmission peaks.

The second clinical study investigating the surgical method for the kineticomyographic control implementation of the bionic hand

In 2018, during our first clinical study on the kineticomyographic (KMG)-controlled bionic hand, we implanted three magnetic tags inside the musculotendinous junction of three paired extensor-flexor transferred tendons. However, the post-operative tissue adhesions affected the independent movements of the implanted tags and consequently the distinct patterns of the obtained signals. To overcome this issue, we modified our surgical procedure from a one-stage tendon transfer to a two-stage. During the first surgery, we created three tunnels using silicon rods for the smooth tendon gliding. In the second stage, we transferred the same three pairs of the forearm agonist–antagonist tendons through the tunnels and implanted the magnetic tags inside the musculotendinous junction. Compared to our prior clinical investigation, fluoroscopy and ultrasound evaluations revealed that the surgical modification in the current study yielded more pronounced independent movements in two specific magnetic tags associated with fingers (maximum 5.7 mm in the first trial vs. 28 mm in the recent trial with grasp and release) and thumb (maximum 3.2 mm in the first trial vs. 9 mm in the current trial with thumb flexion–extension). Furthermore, we observed that utilizing the flexor digitorum superficialis (FDS) tendons for the flexor component in finger and thumb tendon transfer resulted in more independent movements of the implanted tags, compared with the flexor digitorum profundus (FDP) in the prior research. This study can help us plan for our future five-channel bionic limb design by identifying the gestures with the most significant independent tag displacement.

Convective heat transfer across silicon rods under uniform wall heat flux in a laboratory-scale Siemens reactor

The effects of operating and geometric parameters on convective heat transfer (CHT) in Siemens reactor with a laboratory-scale are investigated. A dimensionless analysis of the CHT is performed considering the flow characteristics, rod diameter (d), rod length (L), number of rods, and the distance between adjacent silicon rods. A dimensionless parameter (Hou) is proposed to represent the number of rods and the distance between adjacent rods. Additionally, three dimensionless parameters that affect the CHT, namely, the Rayleigh number, d/L, and Hou, are obtained. The two-factor interaction effects of the dimensionless parameters on the CHT are analyzed, and their relationships are determined for calculating the CHT flux. Based on these relationships, the Nusselt number is calculated for 7- and 8-rod laboratory-scale Siemens reactors, and the relative errors between the predicted and calculated results are 1.4 and 3.2 %, respectively.

A novel 2D-PhC based ring resonator design with flexible structural defects for CWDM applications

In this article, a chain-shaped photonic crystal-based ring resonator (PhCRR), which can function as a channel drop filter (CDF), is designed using two-dimensional photonic crystals. Silicon rods with a refractive index of 3.44 are chosen, and they are perforated in the air with a refractive index of 1 for the PhCRR layout design. Silicon material is selected for realizing the PhCRR-based channel drop filter because it exhibits nearly zero absorption in the C-band (1530–1565 nm) spectral region. The PhCRR structure is established within two-dimensional hexagonal lattices. Transmission efficiency, quality factor, and sensitivity are critical parameters in the design of optical components. Our proposed ring resonator achieves a transmission efficiency of 99.7% with a quality factor of 4550 at a wavelength of 1551 nm. To analyze the drop filter’s functionality, we calculate the electric field distribution of two-dimensional photonic crystals at 1551 nm and 1553 nm. We employ the FDTD numerical analyser to extract simulation results, and the plane wave expansion solver method is used to estimate the photonic band gap of the designed resonator. The chain-shaped photonic crystal-based ring resonator is designed to operate in the third optical window wavelength, which offers very low loss (less than 0.2 dB). The proposed PhCRR is designed to operate within the conventional band range of 1530 to 1565 nm and can be used for various applications such as tunable add/drop multiplexing, optical filters, signal routing and switching in CWDM applications, free space communication systems, and photonic integrated circuits.

Safety outcomes of the first Rigi10™ malleable penile prostheses implanted worldwide.

Implantation of penile prosthesis is considered when conservative measures fail or are unacceptable to patients' wishing treatment for erectile dysfunction. In the United States (US), inflatable penile prostheses are more often used than malleable penile prostheses (MPP). Outside the US, the reverse is true because third-party reimbursement is not available, and MPP is considerably cheaper. Two American manufacturers make MPP; presently, a new manufacturer, Rigicon (Ronkonkoma NY), has recently begun to sell its MPP worldwide. Patient information forms submitted to the manufacturer between March 1, 2019, and December 8, 2022, were used to conduct an initial safety study for 605 first-time patients implanted with Rigicon10® by 46 physicians in 15 countries with a mean follow-up of 21.6 months. It has the same configuration of trimmable, paired silicone rods containing a twisted stainless-steel wire for bendability. However, it is available in six widths with hydrophilic coating compared to three widths offered by competitors. Revision or explantation was needed in 6 of 605 patients (0.99%) with half of those being removed for dissatisfaction (0.50%). Two (0.33%) suffered device infection and one (0.16%) required removal for erosion. Kaplan-Meier's statistical analysis showed three-year implant survival from revision = 99.2%. It demonstrated a comparable safety record with less than 1.00% of patients requiring reoperation.