微创手术治疗脊柱转移瘤的临床研究

目的:探索经皮椎弓根螺钉联合微创治疗手段在脊柱转移瘤中的疗效。方法:回顾性分析2019年10月至2021年9月天津医科大学肿瘤医院收治的脊柱转移瘤患者15例。患者均行经皮椎弓根螺钉联合微创治疗,术后给予综合治疗,治疗前和治疗后3个月对患者疼痛、神经损伤、功能状态等进行评估。结果:患者随访3~23个月,平均生存时间为13.5个月,中位生存时间14.0个月。平均手术时间为(232.3±17.9)min,术中出血量为(393.3±64.9)mL,椎体骨水泥平均注射量3.38 mL。治疗前VAS评分(7.67±0.25)分,术后3个月VAS评分(2.73±0.15)分,治疗后疼痛明显缓解(P<0.01);14例患者Frankel分级提高1个等级,1例患者术前为Frankel D级,经过微创手术治疗后分级无变化;术前、术后3个月KPS评分得到明显改善(P<0.01)。结论:经皮椎弓根螺钉联合小切口椎板减压手术能够有效缓解脊髓压迫症状,减轻疼痛,提高患者生存质量。

Coherence entropy during propagation through complex media

The deformation,flicker,and drift of a light field owing to complex media such as a turbulent atmosphere have limited its practical applications.Thus,research on invariants in randomly fluctuated light fields has garnered considerable attention in recent years.Coherence is a statistical property of light,while its full and quantitative characterization is challenging.Herein,we successfully realize the orthogonal modal decomposition of partially coherent beams and introduce the application of coherence entropy as a global coherence characteristic of such randomly fluctuated light fields.It is demonstrated that coherence entropy remains consistent during propagation in a unitary system by unraveling complex channels.As representative examples,we study the robustness of coherence entropy for partially coherent beams as they propagate through deformed optical systems and turbulent media.Coherence entropy is anticipated to serve as a key metric for evaluating the propagation of partially coherent beams in complex channels.This study paves the way for a broader application scope of a customized low-coherence light field through nonideal optical systems and complex media.

Single-shot phase retrieval for randomly fluctuated and obstructed vortex beams

Vortex beams with orbital angular momentum play a crucial role in increasing the information capacity in optical communications.The magnitude of orbital angular momentum determines the ability of information encoding.In practice,a vortex beam can encounter random objects or turbulence during free-space propagation,resulting in information damage.Therefore,accurately measuring the orbital angular momentum of a randomly fluctuated and obstructed vortex beam is a considerable challenge.Herein,we propose a single-shot method for the phase retrieval of a randomly fluctuated and obstructed vortex beam by combining the phase-shift theorem and self-reference holography.Experimental results reveal that the sign and magnitude of the initial orbital angular momentum can be simultaneously determined based on their quantitative relation with the number of coherence singularities on the observation plane,thus addressing the effects of random occlusion and atmospheric turbulence.The proposed method considerably improved the accurate decoding of orbital angular momentum information in nonideal freespace optical communications.

Coherence phase spectrum analyzer for a randomly fluctuated fractional vortex beam

Fractional vortex beams exhibit a higher degree of modulation dimensions than conventional vortices,thus inheriting superior anti-turbulent transmission properties through the incorporation of additional coherence modulation.However,aliasing the mixed modes induced by coherence degradation makes the quantitative measurement of the topological charge in fractional vortex beams challenging.In this study,a coherence phase spectrum was introduced,and experimental demonstrations to quantitatively determine the fractional topological charge of partially coherent fractional vortex beams were performed.By leveraging the four-dimensional measurement of a partially coherent light field,the source coherence function was inversely reconstructed,and fractional topological charges were determined with high precision by extracting the phase spectrum of the coherence function.Laguerre–Gaussian,elliptical Gaussian,and plane-wave-fraction vortex beams with various degrees of coherence were used to demonstrate measurement precision.The proposed method is applicable to X-rays and electron vortices.It has potential applications in optical encryption,high-capacity optical communication,and quantum entanglement.

Rotational Doppler effect of composite vortex beams with tailored OAM spectra

There recently has been increasing interest in the research and application of the rotational Doppler effect(RDE),which paves a promising way to detect rotating objects remotely.In order to obtain more information about the rotating object from the rotational Doppler signal,composite vortex beams by coaxial superposition of orbital angular momentum(OAM)modes are often used as the probe beam.However,to the best of our knowledge,the RDE of composite vortex beams with arbitrary OAM spectra has not yet been comprehensively studied.In this paper,the correspondence between the OAM spectrum of a probe beam and the frequency spectrum of a rotational Doppler signal is theoretically analyzed.It is explicitly revealed that the RDE frequency spectrum of scattered light is related to the product of two autocorrelation functions:one from the OAM spectrum of probe beam and the other from the spiral spectrum of rotating object.On the basis of this relation,one can regulate the RDE frequency spectrum on demand via tailoring the OAM spectrum of the probe beam.As a proof of concept we design a special composite vortex beam to eliminate the broadening of the RDE spectrum induced by misalignment.These findings are of practical value in applications such as remote sensing and optical metrology.

Economical generation of high-quality optical vortices with gradual-width Fermat spiral slit mask

A general model for creating an optical vortex using a variable-width Fermat spiral slit(FSS)mask was developed.The generated optical vortex demonstrates much better quality than those produced by slits with a uniform width.The depth of focus was nearly doubled,which can be explained by discretizing the gradual-width FSS.To demonstrate the generation robustness,the slits were printed on a transparent slide,and an output vortex beam with greater than 98%intensity purity was obtained.With the high quality and simplicity of this vortex generation method,its analysis and generation scheme are expected to be extended to generation of plasmonic vortices and short-wavelength light sources such as X-rays and electron beams.Generation of highquality optical vortex beams at an almost negligible cost will make investigation much more accessible.

Review on partially coherent vortex beams

Ever since vortex beams were proposed, they are known for owning phase singularity and carrying orbital angular momentum (OAM). In the past decades, coherent optics developed rapidly. Vortex beams have been extended from fully coherent light to partially coherent light, from scalar light to vector light, from integral topological charge (TC) to fractional TC. Partially coherent vortex beams have attracted tremendous interest due to their hidden correlation singularity and unique propagation properties (e.g., beam shaping, beam rotation and self-reconstruction). Based on the sufficient condition for devising a genuine correlation function of partially coherent beam, partially coherent vortex beams with nonconventional correlation functions (i.e., non-Gaussian correlated Schell-model functions) were introduced recently. This timely review summarizes basic concepts, theoretical models, generation and propagation of partially coherent vortex beams.

Nano-heterogeneity-stabilized and magnetic-interaction-modulated metallic glasses

Because of their boundary-free and long-rangedisordered microstructure,Fe-based metallic glasses(MGs)exhibit an ultra-low pinning effect on the magnetic domain and unparalleled soft-magnetic properties[1-3],and thus are increasingly used in electric devices for the energy-saving and high-efficiency requirements[4,5].

Partially coherent vortex beams:Fundamentals and applications

It has been over 30 years since the concept of optical vortices was first proposed by Coullet et al.in 1989,and the field of structured beams has grown extremely.In the last two decades,partially coherent vortex beams(PCVBs)have received increasing interest in the fields of optical manipulation,optical communication,optical imaging,etc.,and great progress has been made in the area of the coherence singularities,generation methods,topological charge measurements,and promising applications of PCVBs.In this review,we firstly outline the basic concepts of PCVBs.We explicate the relationship between the coherence vortices and optical vortices,and the evolution behavior of optical vortices to coherence vortices is summarized in detail.We discuss a special form of coherence singularity,ring dislocation,mathematically and physically.The ring dislocation in the correlation functions under low coherence is dependent on the mode indices,which provide a feasible approach to measure mode indices of PCVBs.Subsequently,we summarize the various methods for measuring the topological charge of PCVBs,highlight the measurement method based on the cross-correlation function,and a physical explanation on the relation between ring dislocation and topological charge is given.After that,we review the recent advances on experimental generation of several kinds of PCVBs.Lastly,we give an overview on the potential applications of PCVBs.

Noniterative spatially partially coherent diffractive imaging using pinhole array mask

We propose and experimentally demonstrate a noniterative diffractive imaging method for reconstructing the complex-valued transmission function of an object illuminated by spatially partially coherent light from the far-field diffraction pattern.Our method is based on a pinhole array mask,which is specially designed such that the correlation function in the mask plane can be obtained directly by inverse Fourier transforming the diffraction pattern.Compared to the traditional iterative diffractive imaging methods using spatially partially coherent illumination,our method is noniterative and robust to the degradation of the spatial coherence of the illumination.In addition to diffractive imaging,the proposed method can also be applied to spatial coherence property characterization,e.g.,free-space optical communication and optical coherence singularity measurement.

Development of soft magnetic amorphous alloys with distinctly high Fe content

This paper reports on the preparation of Fe82.7-85.7Si2-4.9B9.2-11.2P1.5.2.7C0,8 soft magnetic amorphous alloys with a distinctly high Fe content of 93.5-95.5 wt.% by component design and composition adjustment. All alloys can be readily fabricated into completely amorphous ribbon samples with good surface quality by the single copper roller melt-spinning method. These alloys show good bending ductility and excellent magnetic properties after annealing, i.e., low coercivity （He） of 3.3-5.9 A/m, high permeability （μe） of 5000-10000 and high flux saturation density （Bs） of 1.63-1.66 T. The mechanism of the good glass forming ability （GFA）and soft-magnetic properties are explored. The amorphous alloys with the high Fe content comparable to that of the desired high Si alloy can be promising candidates for the potential application in electric devices.

Facile fabrication of ultrathin freestanding nanoporous Cu and Cu-Ag films with high SERS sensitivity by dealloying Mg-Cu(Ag)-Gd metallic glasses

Nanoporous metals prepared by dealloying have attracted increasing attention due to their interesting size-dependent physical,chemical,and biological properties.However,facile fabrication of metallic ultrathin freestanding nanoporous films(UF-NPFs)by dealloying is still challenging.Herein,we report a novel strategy of facile preparation of flexible Cu,Cu_(3)Ag,and CuAg UF-NPFs by dealloying thick Mg-Cu(Ag)-Gd metallic glass ribbons.During dealloying,the local reaction latent heat-induced glass transition of the precursor ribbons leads to the formation of a solid/liquid interface between the initially dealloyed nanoporous layer and the underlying supercooled liquid layer.Due to the bulging effect of in situ generated H2 on the solid/liquid interface,Cu,Cu_(3)Ag,and CuAg UF-NPFs with thicknesses of~200 nm can self-peel off from the outer surface of the dealloying ribbons.Moreover,it was found that the surfaceenhanced Raman scattering(SERS)detection limit of Rhodamine 6G(R6G)on the Cu and CuAg UF-NPF substrates are 10^(-6)M and 10^(-11)M,respectively,which are lower than most of the Cu and Cu-Ag substrates prepared by other methods.This work presents a reliable simple strategy to synthesize a variety of cost effective and flexible metallic UF-NPFs for functional applications.

Facile synthesis of metal and alloy nanoparticles by ultrasound-assisted dealloying of metallic glasses

Metal and alloy nanoparticles synthesized by chemical reduction have attracted increasing attention due to their superior physical,chemical,and biological properties.However,most chemical synthesis processes rely on the use of harsh reducing agents and complicated chemical ingredients.Herein,we report a novel reduction-agent-free and surfactant(stabilizer)-free strategy to synthesize Cu,Ag,Au,Cu-Pt,Cu-Au,Cu-Au-Pt-Pd,and Au-Pt-Pd-Cu nanoparticles by ultrasound-assisted dealloying of Mgbased metallic glasses.The formation mechanism of the metal and alloy nanoparticles is revealed by a detailed investigation of sequential intermediate products.We demonstrate that the glass-liquid phase transition of the initially dealloying metallic glasses,together with the synergistic effect of dealloying and ultrasound-driven ligament-breakage of small enough nanoporous intermediates,play key roles in preparing the uniformly dispersed metal and alloy nanoparticles.This approach greatly simplifies the up-scaling synthesis of monometallic and bimetallic nanoparticles,and also provides a general strategy for synthesizing unprecedented multimetallic nanoparticles.