Search

Objective To investigate the clinical effect of individualized 3D printing guide assisted upper cervical pedicle screw placement. Methods Eighteen patients with upper cervical spine injury requiring surgical treatment were included in our hospital from May 2010 to May 2019. These patients were divided into guide plate assisted screw implantation group (Group A, N = 10) and traditional operation group (Group B, N = 8). All patients were followed up for more than 6 months. Screw implant accuracy, cervical spine JOA score, ASIA score, VAS score, operation time, intraoperative blood loss were compared between the two groups. Result A total of 72 atlantoaxial pedicle screws were implanted, 40 in group A and 32 in group B. The accuracy rate of nail implantation was 97.50% in group A and 81.25% in group B (P P P P

An optimization for all-fiber narrowband Yb-doped superfluorescent source with a central wavelength shorter than 1040 nm is conducted theoretically and then verified experimentally using steady-state rate equations. Theoretical investigation indicates that with the increase in fiber length, signal power presents one peak value, but the ratio of signal power to output power is decreasing monotonously. Moreover, a filter with high extinction ratio and a gain fiber with high absorption coefficient can have gain suppression on a long wavelength. One all-fiber superfluorescent source is built experimentally on the basis of the theoretically optimized parameters. The source achieves an output power of 214.64 W with a central wavelength of 1034.18 nm and signal–noise ratio of 30 dB. The output power of the source can have further power scaling with considerable available pump power.

Aims Increased resistin (Retn) levels are associated with development of cardiovascular diseases. However, the role of Retn in heart failure (HF) is still unclear. Here we probed the functional and molecular mechanism underlying the beneficial effect of Retn deletion in HF. Methods and results Wild-type (WT) and adipose tissue-specific Retn-knockout (RKO) mice were subjected to transverse aortic constriction (TAC)-induced HF. Cardiac function and haemodynamic changes were measured by echocardiography and left ventricular catheterization. Adipose tissue Retn deletion attenuated while Retn cardiac-selective overexpression, via a recombinant adeno-associated virus-9 vector, exacerbated TAC-induced hypertrophy, cardiac dysfunction, and myocardial fibrosis in WT and RKO mice. Mechanistically, we showed that Gadd45α was significantly increased in RKO HF mice while cardiac overexpression of Retn led to its downregulation. miR148b-3p directly targets Gadd45α and inhibits its expression. Retn overexpression upregulated miR148b-3p expression and triggered DNA damage response (DDR) in RKO-HF mice. Inhibition of miR148b-3p in vivo normalized Gadd45α expression, decreased DDR, and reversed cardiac dysfunction and fibrosis. In vitro Retn overexpression in adult mouse cardiomyocytes activated miR148b-3p and reduced Gadd45α expression. Gadd45α overexpression in H9C2-cardiomyoblasts protected against hydrogen peroxide- and Retn-induced DDR. Conclusion These findings reveal that diminution in circulating Retn reduced myocardial fibrosis and apoptosis, and improved heart function in a mouse model of HF, at least in part, through attenuation of miR148b-3p and DDR. The results of this study indicate that controlling Retn levels may provide a potential therapeutic approach for treating pressure overload-induced HF.

Distributed Fiber Optic Sensing is increasingly recognized as a viable alternative to geophone arrays for the acquisition of borehole seismic data. The ability to deploy optical fibers into a well, either as a cable based intervention or as part of a completion string, allows for the entire wellbore to be surveyed with every source activation. This can dramatically reduce the operating time required to complete a normal survey as well as offering the opportunity to achieve much higher spatial coverage than is typical of current technologies. The ability to acquire borehole seismic data in a producing well without the need to disrupt production also offers significant benefits to the operator. Distributed acoustic sensing (DAS) is a novel technology that uses an optical fiber cable as a sensor for acoustic signals and can take almost any downhole fiber-optic installation or deployment and turn the fiber optic cable into a large downhole seismic array. This array can provide enhanced Vertical Seismic Profile (VSP) imaging and monitor fluids and pressures changes in the hydrocarbon production reservoir. Walkaway VSP data acquired over a former producing well in north eastern China provided a rich set of very high quality DAS Walkaway VSP data. A standard VSP data pre-processing workflow was applied, followed by prestack Kirchhoff time migration. In the DAS pre-processing step we were faced with additional and special challenges: strong coherent noise due to cable slapping and ringing along the borehole casing. In comparison with an earlier offset VSP data set using 327-levels acquired with conventional 3C downhole geophones in the same well, the final pre-processed DAS walkaway VSP has a larger vertical aperture resulting in a wider lateral image. The single well DAS Walkaway VSP images provide a good result with higher vertical and lateral resolution than the surface seismic in the objective area. The vertical well environment without the ability to effectively “clamp” the sensor to the borehole casing wall by touching, creates a unique set of challenges. Although earth signal was recorded with almost all the shots, there was also a considerable amount of noise. Much of the noise was due to the physical placement of the wireline in the well and expressed by slapping and ringing. This paper reports on lessons learned in the handling of the wireline cable and subsequent special DAS data processing steps developed to remediate some of the practical wireline deployment issues. Optical wireline cable as a conveyance of fiber optic cables for VSP in vertical wells will open the use of the DAS system to much wider applications.

An all-fiber tunable, narrowband superfluorescent source is presented by using tunable seed source and two amplification stages. The output power reaches over 30 W with the tuning range of ∼35 nm (from ∼1045 to ∼1080 nm) and the slope efficiency in the final amplifier is about 67%. At the maximum output power, the full width at half maximum is about 0.7 nm and the signal-noise ratio reaches over 25 dB. More output power can be realized by simply adding pump source. To the best of our knowledge, it is the first time to use all-fiber configuration to realize the tunable output at 1 μm superfluorescent fiber source region.

The influence of temperature on the output spectra and power of Yb-doped superfluorescent fiber source are investigated through a temperature-dependent model. The model is composed of steady-state rate equations and temperature-dependent cross section functions. Simulation results indicated that with temperature varying from 0 °C to 100 °C, the central wavelengths of the forward and backward output spectra shift from 1061.8 nm to 1070.8 nm and from 1045.8 nm to 1068.8 nm, respectively. Meanwhile, the total output power has a 15.3% reduction. These trends are further verified experimentally. This study offers a concise way of acquiring a superfluorescent fiber source with different central wavelengths.

Background: Cardiac fibrosis (CF) is a major cause of heart failure in patients with ischemic insult, obesity, and diabetes. CF, characterized by excessive deposition of extracellular matrix proteins and myofibroblast differentiation, leads to profound changes in ventricular architecture and geometry, and thereby reduces cardiac function. Resistin, an adipokine has been linked to obesity, insulin resistance and diabetes. Our previous findings have implicated resistin in CF, however the molecular mechanisms underlying this process are still unclear. In this study, we investigated whether resistin regulates the transdifferentiation of fibroblasts into myofibroblasts as well as the molecular pathways leading to resistin-induced fibrotic response. Methods: Fibroblast-to-myofibroblast differentiation was induced with resistin, TGFβ1 or FBS for 48hours in isolated cardiac fibroblasts from adult mouse and mouse embryonic fibroblasts (NIH3T3 cells). Resistin knockout mice were challenged with high fat diet for 16 weeks to stimulate cardiac lipotoxicity. Fibrotic response and markers were determined in harvested hearts. Results: Adult cardiac fibroblasts stimulated with resistin displayed increased fibroblast-to-myofibroblast differentiation, with significantly increased levels of collagen, fibronectin, and connective tissue growth factor. Mechanistically, we demonstrated that resistin promotes fibrogenesis via Jak-Stat and c-Jun signaling pathways, independently of TGFβ1. In-vivo study confirmed the role of resistin in cardiac fibrosis. Resistin knockout mice, when challenged with high fat diet to stimulate cardiac lipotoxicity, showed a decrease in fibrosis paralleled with reduced mRNA levels of various markers of fibrosis such as collagen, fibronectin and connective tissue growth factor compered to wild type hearts. A significant improvement in heart function was also observed in resistin knockout mice. Conclusions: To our knowledge, these findings are the first to demonstrate a role of resistin in the process of cardiac fibroblast-to-myofibroblast conversion through Jak-Stat and c-Jun signaling. These results bring new insights into the mechanisms by which resistin may contribute to cardiac fibrosis.

Cardiac fibrosis is characterized by excessive deposition of extracellular matrix proteins and myofibroblast differentiation. Our previous findings have implicated resistin in cardiac fibrosis; however, the molecular mechanisms underlying this process are still unclear. Here we investigated the role of resistin in fibroblast-to-myofibroblast differentiation and elucidated the pathways involved in this process. Fibroblast-to-myofibroblast transdifferentiation was induced with resistin or TGFβ1 in NIH-3T3 and adult cardiac fibroblasts. mRNA and protein expression of fibrotic markers were analyzed by qPCR and immunoblotting. Resistin-knockout mice, challenged with a high-fat diet (HFD) for 20 weeks to stimulate cardiac impairment, were analyzed for cardiac function and fibrosis using histologic and molecular methods. Cardiac fibroblasts stimulated with resistin displayed increased fibroblast-to-myofibroblast conversion, with increased levels of αSma, col1a1, Fn, Ccn2 and Mmp9, with remarkable differences in the actin network appearance. Mechanistically, resistin promotes fibroblast-to-myofibroblast transdifferentiation and fibrogenesis via JAK2/STAT3 and JNK/c-Jun signaling pathways, independent of TGFβ1. Resistin-null mice challenged with HFD showed an improvement in cardiac function and a decrease in tissue fibrosis and reduced mRNA levels of fibrogenic markers. These findings are the first to delineate the role of resistin in the process of cardiac fibroblast-to-myofibroblast differentiation via JAK/STAT3 and JNK/c-Jun pathways, potentially leading to stimulation of cardiac fibrosis.

Tunable, narrowband superfluorescent fiber sources (SFSs) are significantly important for spectral combination. Here, we propose a high power, tunable, ultra-narrowband Yb-doped SFS operating at wavelength less than 1055 nm with 20 nm tuning range. The system is composed of a broadband SFS, a home-mode space-to-fiber tunable spectral filter, and a three-stage amplifier chain. In order to achieve three typical characteristics, namely, operating in the shorter wavelength region (SWR) with wide spectrum, tunable and narrowband, and high-power output, the performance of the system is investigated and optimized based on the rate equations with temperature, grating monochromator and the coupling theory of Gaussian beam between fibers. Theoretical investigation indicates that a broadband SFS operating in the SWR with wide spectrum can be achieved by controlling temperature within a certain range. Moreover, by optimizing space-to-fiber tunable spectral filter, the tunable, ultra-narrowband SFS with linewidth of 0.088 nm can be obtained. In addition, the seed laser with signal to noise ratio (SNR) of more than 30 dB and the appropriate length of active fiber can gain better amplification performance from the main amplifier. Based on these optimized parameters, a high power, tunable, ultra-narrowband Yb-doped SFS has been built experimentally. The output power of narrowband SFS operating in tunable range from 1035 nm to 1055 nm exceeds 300 W with M2 factor of 1.47, and the measured full width at half maximum and SNR of which are less than 0.1 nm and beyond 30 dB, respectively. This work extends the spectral region and capacity of narrowband SFSs, and will be useful for further power scaling of spectral beam combination.

Distributed acoustic sensing (DAS) is a novel technology that uses an optical fiber cable as a sensor for acoustic signals and can take almost any downhole fiber-optic installation or deployment and turn the fiber-optic cable into a large downhole seismic array. This array can provide enhanced vertical seismic profile (VSP) imaging and monitor fluids and pressure changes in the hydrocarbon-production reservoir. Walkaway VSP data acquired over a formerly producing well in northeastern China provided a rich set of high-quality DAS walkaway VSP data. A standard VSP data preprocessing workflow was applied, followed by prestack Kirchhoff time migration. In the DAS preprocessing step, we were faced with additional challenges: strong coherent noise due to cable slapping and ringing along the borehole casing. Compared with an earlier offset VSP data set using 327 levels acquired with conventional 3C downhole geophones in the same well, the final preprocessed DAS walkaway VSP has a larger vertical aperture, resulting in a wider lateral image. The single-well DAS walkaway VSP images provide a good result with higher vertical and lateral resolution than the surface seismic in the objective area. The vertical-well environment, which lacks the ability to effectively “clamp” the sensor to the borehole-casing wall by touching, creates a unique set of challenges. Although earth signal was recorded with almost all the shots, there was also a considerable amount of noise. Much of the noise was due to the physical placement of the wireline in the well and was expressed by slapping and ringing. Reported here are lessons learned in handling the wireline cable and subsequent special DAS data processing steps developed to remediate some of the practical wireline deployment issues. Optical wireline cable as a conveyance of fiber-optic cables for VSP in vertical wells will open the use of the DAS system to wider applications.

We propose a method for a high-power tunable sub-nm narrowband near-diffraction-limited superfluorescent fiber source (SFS) based on a single-lens spectral filter (SLSF), which is composed of a grating monochromator and a movable space-fiber coupler. The center wavelength of the SLSF is set to 1063 nm with a full width at half-maximum (FWHM) linewidth of less than 0.08 nm. By utilizing the SLSF and a broadband amplified SFS, a tunable sub-nm narrowband SFS seed source is obtained, and the central wavelength of the sub-nm narrowband SFS seed source can be easily tuned from 1052.4 nm to 1072.8 nm by adjusting the SLSF. After a three-stage amplifier system, the output power of this sub-nm narrowband SFS is boosted to 230W with the FWHM range from 0.10 nm to 0.12 nm. The beam quality factors (M2) of the full power sub-nm narrowband SFS at 1060.1 nm is 1.20. The proposed tunable sub-nm SFS has advantages of high spectral resolution, simple configuration, which may have potential applications in the industrial production and scientific research.

A silane-bridged polyaniline (PANI)/cotton fiber (CF) composite (designated as PANI/SCF) was prepared by a novel and facile approach in the current study. Aniline-bearing silane molecules were first grafted onto the CF surface through a condensation reaction between hydroxyl groups of cellulose and the silane molecules. Subsequent oxidative polymerization of aniline in the presence of silane-modified CF (SCF) yielded the final PANI/SCF composite, which can be used as the potential Cr(VI) adsorbent. Results showed that the optimal silane grafting conditions were: 0.01 mol/L HAc, EtOH/water volume ratio 95/5, reaction temperature 40 °C and silane dosage 0.1 g (per 0.5 g CF). Using SCF that prepared under the optimal conditions as the substrate, about 4.6% of PANI can be deposited, mostly existing as nanorods and distributing more evenly than those on the raw CF surface. FTIR and XPS analyses further testified the successful chemical bonding of silane and the final deposition of PANI on the fiber surfaces. In comparison with neat PANI, the solid–liquid separation can be achieved by simply taking the fibrous adsorbent out. Besides, the adsorption capacity of PANI/SCF on the basis of PANI mass (dividing Q m by PANI content) was much higher, probably due to the uniform distribution of PANI nanostructures on SCF and the high efficiency of PANI nanostructures in Cr(VI) adsorption.

A novel kind of single-mode large-mode-area optical fiber is presented in this paper. The proposed fiber core is composed of high-index central rod and the surrounding multilayer rings. The mode characteristics are discussed considering the fiber structure parameters. The calculation results show that the proposed fiber possesses extreme large mode area of 2975 mu m(2) with single mode operation at the wavelength of 1.08 mu m. Even larger mode area of the complex ring core fiber with single mode output can be achieved by coiling the fiber, due to the significant difference of bending loss between the fundamental mode and the higher-order transverse modes. Such fibers are expected to find applications in the field of fiber lasers and amplifiers. (C) 2014 Elsevier GmbH. All rights reserved.

The midterm effects of cardiac telocytes (CTs) transplantation on myocardial infarction (MI) and the cellular mechanisms involved in the beneficial effects of CTs transplantation are not understood. In the present study, we have revealed that transplantation of CTs was able to significantly decrease the infarct size and improved cardiac function 14 weeks after MI. It has established that CT transplantation exerted a protective effect on the myocardium and this was maintained for at least 14 weeks. The cellular mechanism behind this beneficial effect on MI was partially attributed to increased cardiac angiogenesis, improved reconstruction of the CT network and decreased myocardial fibrosis. These combined effects decreased the infarct size, improved the reconstruction of the LV and enhanced myocardial function in MI. Our findings suggest that CTs could be considered as a potential cell source for therapeutic use to improve cardiac repair and function following MI, used either alone or in tandem with stem cells.

High-power fiber lasers have been widely explored in engineering and science, and improving the beam quality restricted by transverse mode instability (TMI) is waiting to be solved for extra high-power applications. Here, we theoretically propose a phase transition model for understanding TMI in a fiber oscillator. A general dynamics model describing TMI is established by modifying the heat equation, and then a special dynamics model of a two-mode fiber (TMF) oscillator is obtained by applying this general dynamics model to TMF oscillator case. Theoretical analysis shows that there is a reversible phase transition point in this TMF oscillator model, which can well explain the sudden and reversible change of TMI. Based on linear stability analysis near the phase transition point, an analytical threshold formula of TMI is given to calculate the TMI threshold in the TMF oscillator. The calculated results are consistent with the reported experimental results. Furthermore, the relationship between the TMI threshold and several parameters was also discussed in detail such as laser wavelength, pump wavelength, core radius, cladding radius, etc. This theoretical model will be useful to understand and suppress the TMI in fiber oscillators.

A triangle-platform-index core fiber is proposed, in which the refractive index distribution in the cross-section of the fiber core is composed of several closely connected triangles and a platform at the outermost layer. The simulation results show that the proposed fiber possesses an extremely large mode field area of [Formula: see text] at the wavelength of [Formula: see text], and achieves single-mode operation state near a bend radius of 17 cm. Furthermore, several different mode field distributions, including Gauss-like distribution, flatten distribution and hollow distribution, are achieved. The proposed fiber can benefit suppressing nonlinear phenomenon to increase the output power level of fiber laser, and promoting special industrial processing.

We demonstrate the incoherent beam combining (BC) of four high-power single-mode fiber lasers. Adaptive fiber-optics collimators (AFOC) of 0.5 kW-level are developed to correct the tip/tilt-type phase errors among beamlets. The maximum deflection angle of the AFOC is about 0.29 mrad. A stochastic parallel gradient descent algorithm is employed as the tip/tilt control strategy. The tip/tilt control makes four separate laser beams overlap with each other in the far-field, and the average of normalized power-in-bucket increases from 0.171 in open loop to 0.798 in closed loop when 1.5-kW total output power is achieved. The precise tracking ability and control accuracy of this BC system are investigated. Experimental results expose that thermal-blooming effect disturbs BC seriously when the total output power is up to kW-level, which could be mitigated by inducing air flow near the laser output.

A theoretical analysis of stimulated Brillouin scattering (SBS) in linear cavity Yb3+ doped dual-clad fiber lasers is presented by solving the steady-state rate equations with SBS included. Solutions to suppress the detrimental effect in the fiber laser are discussed. It is shown that the first-order Stokes initiated by forward and backward pump light changes exponentially along the fiber, and laser power reduces greatly in the presence of SBS under bidirectional end pump. Furthermore, it is found that the SBS threshold power can be improved effectively by using large mode area fiber and shortening the cavity length. (C) 2013 Elsevier GmbH. All rights reserved.

Recently, cardiac telocytes were found in the myocardium. However, the functional role of cardiac telocytes and possible changes in the cardiac telocyte population during myocardial infarction in the myocardium are not known. In this study, the role of the recently identified cardiac telocytes in myocardial infarction (MI) was investigated. Cardiac telocytes were distributed longitudinally and within the cross network of the myocardium, which was impaired during MI. Cardiac telocytes in the infarction zone were undetectable from approximately 4 days to 4 weeks after an experimental coronary occlusion was used to induce MI. Although cardiac telocytes in the non-ischaemic area of the ischaemic heart experienced cell death, the cell density increased approximately 2 weeks after experimental coronary occlusion. The cell density was then maintained at a level similar to that observed 1–4 days after left anterior descending coronary artery (LAD)-ligation, but was still lower than normal after 2 weeks. We also found that simultaneous transplantation of cardiac telocytes in the infarcted and border zones of the heart decreased the infarction size and improved myocardial function. These data indicate that cardiac telocytes, their secreted factors and microvesicles, and the microenvironment may be structurally and functionally important for maintenance of the physiological integrity of the myocardium. Rebuilding the cardiac telocyte network in the infarcted zone following MI may be beneficial for functional regeneration of the infarcted myocardium.

Based on a steady-state rate equations (REs) and heat dissipation model considering both convective and radiative heat transfer, the output performance and temperature distribution of Yb 3+ doped gain guided and index antiguided (GG–IAG) fiber lasers by multipoint distributed pumping are analyzed by numerically solving REs. The results show that high output power and even temperature distribution can be obtained by increasing pump points and lowering the losses at the points; multipoint side pumping is an optimal method to obtain compact high power GG–IAG fiber lasers. The numerical analysis provides some insights for the construction of high power GG–IAG fiber lasers.

Coupling properties of two gain-guided index-antiguided (GG + IAG) fibers or GG+IAG fibers and index-guided (IG) fibers were investigated by the further general coupled mode theory The theory can explain any situation of two fiber coupling The interesting results were obtained by the numerical computation method For two GG + IAG fiber coupling total power was decreased as rising real-valued refractive-index difference (real part of refractive-index difference between core and cladding RVRID) while the power of one GG + IAG fiber was damped oscillations with Increased core separation In the GG + IAG fiber and IG fiber coupler the variation of the RVRID could change coupling characteristics These results are different from two IG fibers coupling and the general coupled-mode theory may provide meaningful references for new concepts of directional coupler and pumping technology of GG+IAG fiber Crown Copynght (C) 2010 Published by Elsevier BV All rights reserved

A four-wave mixing effect on high-power continuous-wave fiber lasers has been demonstrated theoretically and experimentally. Detailed theoretical description of phase matching is presented and we found that the phase matching condition is satisfied at the frequency shift of 5.16 THz. While the intensity in fiber core region is more than about 394 MW/cm2, the four-wave mixing products of 1100 nm and 1060 nm were also observed in high-power all-fiber laser. The comparison shows that the experiment result is in good agreement with the simulation result. In addition, the beam quality deterioration for the laser is caused by the four-wave mixing effect and the mode instability. The [Formula: see text] factor measured at maximal intensity of 478 MW/cm2 is 2.80.

By using a novel mutual injection technique, phase-locking and coherent combining of two high-power all-fiber lasers are realized and experimentally demonstrated. Steady interference strips with high visibility of 46% are observed. The coherent combined 407 W CW output power with a power-combining efficiency of up to 98% is obtained. The laser array works well with excellent stability. In the long time of high-power operation no thermal distortions or damages are observed. The proposed technique can be used to further scale up the coherent combined output power of high-power fiber lasers.

Within the framework of the paraxial approximation, a simple Fourier lens system has been proposed and a series of finite Gaussian modes with different parameters is chosen as the desired field function in place of the rectangular function to construct on-axis flat-top beams. The analytical expressions for the incident field and output on-axis field are derived. The on-axis flat-top intensity distribution is achievable after passage through the lens so long as LS c ≥ 1.5, where L is a measure of the flat-top length of the desired field function and S c is the central longitudinal spatial frequency. Within the region of the on-axis flat top the radial intensity distribution is similar to that of J 0-Bessel beams. The results are illustrated by numerical examples and compared with the previous work.

We report on a 126 W fiber laser operating at 1018 nm with an optical efficiency of 75%. The optimal length for such a fiber laser is theoretically analyzed using steady-state rate equations including amplified spontaneous emission. Excellent agreement on the maximum output power is achieved between the numerical result and the experimental counterpart. Furthermore, a monolithic tandem pumped fiber amplifier is established by using conventional 30/250 μm double clad ytterbium-doped fiber, and 185 W output power with 85% optical efficiency is realized.

A ytterbium-doped double-cladding fiber was successfully fabricated by a chelate gas phase deposited technique. The measurement results of dopant concentration distribution and refractive index of preform indicate that radial and longitudinal homogeneity could be controlled perfectly with this technique. The absorption coefficients of fiber are 0.39 dB/m at 915nm and 1.02 dB/m at 976nm respectively. Using this fiber as the laser amplifier stage, 3592W output power at 1080nm with 72.5% slope efficiency was obtained with end-pump technique, which is close to the test results of Nufern commercial fiber. The results demonstrate that the chelate gas phase deposition technique is a relatively promising technique for high quality gain fiber fabrication.

Establishment of unique animal model to be able to evaluate the structural and functional improvement dynamically after myocardiac infarction (MI) is curtail for developing novel therapy for functional regeneration of infarcted myocardium. In this study, we used the wireless implantable telemetry to monitor the ECG of MI rat under normal activity and treadmill training dynamically. The results of this study show that the in vivo implantable ECG recording technique is able to record the ECG of LAD-ligated heart under normal activity and treadmill training. The model established in this study will be a powerful system for us to evaluate the improvement of infarcted myocardium in structural and functional dimension.

The analytical expression for the propagation of guided optical vortices through free space is derived and used to study the dynamic evolution of guided optical vortices after passing through the free space, and the dependence of guided optical vortices on the control parameters where the effect of propagation distance is stressed. It is shown that the motion, pair creation and annihilation of guided optical vortices may take place. In particular, the creation and annihilation of a pair of guided optical vortices do not take place by varying fiber length.