Single femtosecond pulse writing of a bifocal lens.

In this Letter, a method for the fabrication of bifocal lenses is presented by combining surface ablation and bulk modification in a single laser exposure followed by the wet etching processing step. The intensity of a single femtosecond laser pulse was modulated axially into two foci with a designed computer-generated hologram (CGH). Such pulse simultaneously induced an ablation region on the surface and a modified volume inside the fused silica. After etching in hydrofluoric acid (HF), the two exposed regions evolved into a bifocal lens. The area ratio (diameter) of the two lenses can be flexibly adjusted via control of the pulse energy distribution through the CGH. Besides, bifocal lenses with a center offset as well as convex lenses were obtained by a replication technique. This method simplifies the fabrication of micro-optical elements and opens a highly efficient and simple pathway for complex optical surfaces and integrated imaging systems.

Single-cell RNA sequencing uncovers the cell type-dependent transcriptomic changes in the retrosplenial cortex after peripheral nerve injury.

The retrosplenial cortex (RSC) is a vital area for storing remote memory and has recently been found to undergo broad changes after peripheral nerve injury. However, little is known about the role of RSC in pain regulation. Here, we examine the involvement of RSC in the pain of mice with nerve injury. Notably, reducing the activities of calcium-/calmodulin-dependent protein kinase type II-positive splenial neurons chemogenetically increases paw withdrawal threshold and extends thermal withdrawal latency in mice with nerve injury. The single-cell or single-nucleus RNA-sequencing results predict enhanced excitatory synaptic transmissions in RSC induced by nerve injury. Local infusion of 1-naphthyl acetyl spermine into RSC to decrease the excitatory synaptic transmissions relieves pain and induces conditioned place preference. Our data indicate that RSC is critical for regulating physiological and neuropathic pain. The cell type-dependent transcriptomic information would help understand the molecular basis of neuropathic pain.

[Effect of administration of acupuncture stimulation combined with Gushen Zhuyu Decoction on lumbar function in patients with disc herniation].

OBJECTIVE: To investigate the therapeutic effect of acupuncture stimulation combined with administration of"Gushen Zhuyu Tang"(decoction for consolidating kidney to eliminate blood stasis, DCKEBS) in the treatment of lumbar disc herniation (LDH) patients. METHODS: A total of 147 patients with LDH were randomly divided into DCKEBS, acupuncture and DCKEBS+acupuncture groups (n= 49 cases in each group). The patients of the acupuncture group received a) acupuncture stimulation of Dazhui (GV14), Ganshu (BL18), Shenshu (BL23), Tianshu (ST25), Yanglingquan (GB34), etc., b) fire needle pricking of the topical tendons, cord-like points, tender-points, c) row-needles stimulation of the attachment sites of muscles of the sacroiliac joint or crista iliaca, and d) acupotomy-debonding of the topical high-tension muscles, twice a week for 4 weeks. Those patients of the DCKEBS group were ordered to take DCKEBS [containing fried Yiyiren (Semen Coicis), Shanzhuyu (Fructus Corni), fried Baizhu (Rhizoma Astractylodis), Sangjisheng (Ramulus Loranthi), Duzhong (Cortex Eucommiae), Buguzhi (Fructus Psoraieae), etc.] 150 mL, twice daily, continuously for 4 weeks, and those of the DCKEBS+acupuncture group received the combined treatment mentioned above in the acupuncture and DCKEBS groups. The pain severity was assessed by using visual ana-logue scale (VAS, 0-10 points) and the modified Japan Orthopaedic Association questionnaire (M-JOA) score (0-30 points), separately, and the lumbar range of motion (ROM) and lumbar muscle strength were tested to evaluate the lumbar motor function. The levels of serum tumor necrosis factor α(TNF-α), matrix metalloproteinase-2 (MMP-2), and apoptosis related factors Caspase-3 and Caspase-9 were assayed using ELISA. The total effective rates of the three groups were compared. RESULTS: After the treatment, the VAS and M-JOA scores, contents of serum TNF-α, MMP-2, Caspase-3 and Caspase-9 were significantly decreased (P<0.01), and the myodynamia of lumbar muscular flexor and extensor was considerably increased (P<0.01) in the three groups, and the ROM angles of lumbar extending and buckling were increased (P<0.01) in the DCKEBS+acupuncture group compared with pretreatment. Comparison among the 3 groups showed that the VAS and M-JOA scores, and serum TNF-α, MMP-2, Caspase-3 and Caspase-9 contents of the DCKEBS+acupuncture group were significantly lower than those of both DCKEBS and acupuncture groups (P<0.01), while the ROM angles of lumbar extending and buckling, and the myodynamia of lumbar muscular flexor and extensor were obviously higher in the DCKEBS+acupuncture group than those of the DCKEBS and acupuncture groups (P<0.01). The total effective rate was 93.88%(46/49) in the DCKEBS+acupuncture group, higher than 75.51%(37/49) in the DCKEBS group and 71.43%(35/49) in the acupuncture group (P<0.05). CONCLUSION: Acupuncture combined with DCKEBS can relieve pain, improve lumbar muscle strength and lumbar movement function, and reduce serum TNF-α, MMP-2, Caspase-3 and Caspase-9 levels in LDH patients.

[Core stability training combined with acupuncture in treatment of chronic nonspecific low back pain: a prospective randomized controlled trial].

OBJECTIVE: To investigate the clinical effect of core stability training combined with acupuncture in the treatment of chronic nonspecific low back pain (CLBP). METHODS: Seventy-five CLBP patients were randomly divided into experimental group (n=38) and control group (n=37) according to a random number table. Patients in the control group were required to perform core stability training, whereas those in the experimental group received core stability training combined with fire needle acupuncture, once every two days, three times per week, for four successive weeks. The Oswestry disability index (ODI), visual analogue scale (VAS), lumbar muscular endurance index, clinical efficacy, as well as average electromyographic (AEMG), root mean square (RMS), median frequency (MF), and average median frequency (AMF) values during multifidus muscle contraction in the two groups before and after the treatment were compared. RESULTS: After treatment, ODI, VAS, MF, and AMF of the two groups were lower than those before the treatment (P<0.01), while the lumbar static and dynamic muscular endurance, AEMG, and RMS values were higher (P<0.01). The ODI, VAS, MF, and AMF of the experimental group significantly declined as compared with those of the control group (P<0.01), whereas the lumbar static and dynamic muscular endurance, AEMG, and RMS values were elevated (P<0.01). The total effective rate of the experimental group was 97.14%(34/35), higher than 85.71%(30/35) of the control group(P<0.01). CONCLUSION: Core stability training combined with acupuncture effectively enhances lumbar muscular endurance, improves electromyographic signals of multifidus muscle and lumbar function, and relieves pain, implying the good efficacy of such combined therapy in treating CLBP.

[Effects of acupuncture on plasma endogenous opioid peptides in patients with stroke-associated headache in convalescence].

OBJECTIVE: To observe the clinical effect of acupuncture on patients with stroke-related headache during convalescent and analyze its related factors. METHODS: A total of 116 stroke-related headache patients admitted to the Acupuncture Department of Gongli Hospital of Pudong New Area, Shanghai, from October 2018 to December 2019 were divided into a treatment group and a control group according to a random number table, with 58 cases in each group. Patients in both groups were given conventional treatments for control of blood pressure, blood sugar, blood lipids and anticoagulation. At the same time, patients in the treatment group were treated with "nape seven needles" (acupuncture at Fengfuï¼»GV16ï¼½, bilateral Fengchiï¼»GB20ï¼½, bilateral Tianzhuï¼»BL10ï¼½ and bilateral Wanguï¼»GB12ï¼½)combined with penetration needling for 30 min; patients in the control group were treated with Flunarizine hydrochloride capsules (5 mg). Both interventions were conducted once daily for 4 weeks. The visual analogue scale(VAS) score and integrative sores of headache, and plasma serotonin (5-HT), dopamine (DA), substance P (SP), α-endorphin (α-EP), and ß-endorphin (ß-EP) levels before and after treatment were compared between the two groups. The total therapeutic effective rate of the two groups was calculated. RESULTS: There was no significant difference in VAS score, headache score, plasma 5-HT, DA, SP, α-EP, ß-EP levels between the two groups before treatment (P>0.05). After treatment, both groups have significant decrease in the VAS score, integrative sores of headache, the plasma 5-HT, DA, SP levels (P<0.05), and significant increase in the plasma α-EP and ß-EP levels (P<0.05). At the same time, the VAS score, integrative sores of headache, the plasma 5-HT, DA, SP levels of the treatment group were lower (P<0.05), and the plasma α-EP and ß-EP levels were higher (P<0.05) than those in the control group. The total effective rate of the treatment group(51/58, 87.9%) was higher than that of the control group (42/58, 72.4%, P<0.05). CONCLUSION: Acupuncture therapy can increase the release of endogenous opioid peptide, reduce the secretion of 5-HT, DA, SP, and have a significant effect in treating stroke related headache.

Control of diameter and numerical aperture of microlens by a single ultra-short laser pulse.

We demonstrate a versatile method for fast and flexible fabrication of either one or an array of microlenses. Multi-foci axial intensity distribution generated by a phase pattern displayed on a spatial light modulator irradiates silica, causing ablation and its internal modification. The following wet etching step defines the diameter r, while the radius of curvature R (hence, the focal length f) is maintained the same. As a result, the numerical aperture NA=r/f changes from 0.2 to 0.4 for the same pulse energy (but different number of multi-foci) during ablation. An isotropic wet etching of silica becomes highly anisotropic for the initial stages of etching following the irradiated pattern. Subsequent evolution of the shape is governed by an isotropic silica etch and forms a spherical lens. This method can be extended to other materials and geometries of micro-optical elements.

Plasmonic-Assisted Graphene Oxide Artificial Muscles.

Muscles and joints make highly coordinated motion, which can be partly mimicked to drive robots or facilitate activities. However, most cases primarily employ actuators enabling simple deformations. Therefore, a mature artificial motor system requires many actuators assembled with jointed structures to accomplish complex motions, posing limitations and challenges to the fabrication, integration, and applicability of the system. Here, a holistic artificial muscle with integrated light-addressable nodes, using one-step laser printing from a bilayer structure of poly(methyl methacrylate) and graphene oxide compounded with gold nanorods (AuNRs), is reported. Utilizing the synergistic effect of the AuNRs with high plasmonic property and wavelength-selectivity as well as graphene with good flexibility and thermal conductivity, the artificial muscle can implement full-function motility without further integration, which is reconfigurable through wavelength-sensitive light activation. A biomimetic robot and artificial hand are demonstrated, showcasing functionalized control, which is desirable for various applications, from soft robotics to human assists.

Wet-etching-assisted femtosecond laser holographic processing of a sapphire concave microlens array.

We report rapid and mask-free fabrication of a sapphire concave microlens array by a combined method of femtosecond laser holographic processing and wet etching. The method features high fabrication efficiency, as crater arrays can be created on sapphire through a parallel processing manner, and the subsequent wet etching facilitates the formation of microlens arrays with a smooth surface. More importantly, the size and spacing of the concave microlenses can be well tuned by varying the distance of craters and etching time. Two types of microlens arrays with a spacing of 25 and 40 µm have been successfully fabricated, both of which showed good imaging performance. This method holds great promise for developing sapphire-based micro-optical components.

Liquid-Assisted Femtosecond Laser Precision-Machining of Silica.

We report a systematical study on the liquid assisted femtosecond laser machining of quartz plate in water and under different etching solutions. The ablation features in liquid showed a better structuring quality and improved resolution with 1/3~1/2 smaller features as compared with those made in air. It has been demonstrated that laser induced periodic structures are present to a lesser extent when laser processed in water solutions. The redistribution of oxygen revealed a strong surface modification, which is related to the etching selectivity of laser irradiated regions. Laser ablation in KOH and HF solution showed very different morphology, which relates to the evolution of laser induced plasma on the formation of micro/nano-features in liquid. This work extends laser precision fabrication of hard materials. The mechanism of strong absorption in the regions with permittivity (epsilon) near zero is discussed.

Single-pulse writing of a concave microlens array.

This work developed a method of femtosecond laser (fs-laser) parallel processing assisted by wet etching to fabricate 3D micro-optical components. A 2D fs-laser spot array with designed spatial distribution was generated by a spatial light modulator. A single-pulse exposure of the entire array was used for parallel processing. By subsequent wet etching, a close-packed hexagonal arrangement, 3D concave microlens array on a curved surface with a radius of approximately 120 µm was fabricated, each unit lens of which has designable spatial distribution. Characterization of imaging was carried out by a microscope and showed a unique imaging property in multi-planes. This method provides a parallel and efficient technique to fabricate 3D micro-optical devices for applications in optofluidics, optical communication, and integrated optics.

Nano-ablation of silica by plasmonic surface wave at low fluence.

Formation of ripples by ablation of surfaces of laser-irradiated materials is an example of ultrafast energy delivery. Herein, we report on fs-laser optical imprinting of periodic nano-grooves on silica substrate at only 25% of the laser ablation threshold via an interface plasmonic light localization at the ZnS film (top) interface with silica (bottom) by plasmonic surface wave. The nano-grooves were formed throughout ZnS with the same period and orientation imprinted onto the underlying silica. Based on a detailed account of the multi-photon and avalanche ionization using the Drude model, laser-induced plasmonic ablation describes quantitatively the energy deposition from the top ZnS to the substrate of silica.

Plasmonic nano-printing: large-area nanoscale energy deposition for efficient surface texturing.

The lossy nature of plasmonic wave due to absorption is shown to become an advantage for scaling-up a large area surface nanotexturing of transparent dielectrics and semiconductors by a self-organized sub-wavelength energy deposition leading to an ablation pattern-ripples-using this plasmonic nano-printing. Irreversible nanoscale modifications are delivered by surface plasmon polariton (SPP) using: (i) fast scan and (ii) cylindrical focusing of femtosecond laser pulses for a high patterning throughput. The mechanism of ripple formation on ZnS dielectric is experimentally proven to occur via surface wave at the substrate-plasma interface. The line focusing increase the ordering quality of ripples and facilitates fabrication over wafer-sized areas within a practical time span. Nanoprinting using SPP is expected to open new applications in photo-catalysis, tribology, and solar light harvesting via localized energy deposition rather scattering used in photonic and sensing applications based on re-scattering of SPP modes into far-field modes.

Determination of 17 pyrethroid residues in troublesome matrices by gas chromatography/mass spectrometry with negative chemical ionization.

An analytical method with the technique of QuEChERS (quick, easy, cheap, effective, rugged and safe) and gas chromatography (GC)/mass spectrometry (MS) in negative chemical ionization (NCI) has been developed for the determination of 17 pyrethroid pesticide residues in troublesome matrices, including garlic, onion, spring onion and chili. Pyrethroid residues were extracted with acidified acetonitrile saturated by hexane. After a modified QuEChERS clean-up step, the extract was analyzed by GC-NCI/MS in selected ion monitoring (SIM) mode. An isotope internal standard of trans-cypermethrin-D(6) was employed for quantitation. Chromatograms of pyrethroids obtained in all these matrices were relatively clean and without obvious interference. The limits of detection (LODs) ranged from 0.02 to 6 µg kg(-1) and recovery yields were from 54.0% to 129.8% at three spiked levels (20, 40 and 60 µg kg(-1) for chili, and 10, 20 and 30 µg kg(-1) for others) in four different matrices depending on the compounds determined. The relative standard deviations (RSDs) were all below 14%. Isomerization enhancement of pyrethroids in chili extract was observed and preliminarily explained, especially for acrinathrin and deltamethrin.