Composite Cavity Research Articles

Supplemental Regional Block Anesthesia Reduces Opioid Utilization Following Free Flap Reconstruction of the Oral Cavity: A Prospective, Randomized Clinical Trial

Regional anesthesia has been shown to effectively manage acute pain and reduce opioid utilization in the early postoperative period following colorectal, orthopedic, and thoracic surgeries. The same effect, however, has not been demonstrated in major head and neck surgery. The purpose of this study is to determine whether supplemental regional anesthesia reduces opioid utilization following microvascular free flap reconstruction of the oral cavity. A prospective, randomized clinical trial was conducted for patients undergoing oral cavity reconstruction using microvascular free tissue transfer between January 2020 and March 2022. The predictor variable was a regional anesthetic nerve block, delivered preoperatively, at the flap donor site. The primary and secondary outcomes were opioid utilization, measured in oral morphine equivalent (OME), from postoperative day 1 to 5, and hospital length of stay (LOS), respectively. Covariates included age, sex, tobacco and alcohol history, prior radiation therapy, pathology, oral site, flap type, tracheostomy, and neck dissection. Student's t test, χ2 test, and linear regression models were computed using correlations with 95% confidence intervals (CIs). For all statistical tests, P values of <.05 were regarded as statistically significant. Ninety-eight participants completed the study. The mean age was 56years with 55% male. Forty-eight patients received a presurgical regional anesthesia block, and 50 patients served as control subjects. Bivariate analysis demonstrated an even distribution of all study variables. Total OME utilization was significantly less in the treatment group compared to the control group, (166.32 vs 118.43 OME; 95% CI, 1.32 to 94.45; P=.04). The LOS was comparable (6.60 vs 6.48days; 95% CI, -0.53 to 0.77; P=.71). Tobacco use had a positive effect (B=0.28; 95% CI, 21.63 to 115.31; P=.005) while the block had a negative effect with total OME, (B=-0.19; 95% CI, -90.39 to -0.59; P=.047). The extent of the neck dissection (B=0.207; 95% CI, 0.026 to 1.403; P=.042) was a positive predictor for LOS. Overall, there were no adverse events associated with the regional block throughout the study period. Supplemental regional anesthesia is safe and associated with reduced opioid utilization in patients undergoing vascularized free flap reconstruction of composite oral cavity defects and does not prolong the length of hospitalization.

Effect of triangular porous layer on the transfer of heat and species in a channel‐open cavity

AbstractThis paper addresses the heat and species transfer in a composite cavity linked with a horizontal channel. The cavity comprises a triangular porous layer and one of its vertical sides is exposed to a high temperature and concentration. The mathematical conservation equations are solved numerically using the Galerkin finite element method. The ranges of Reynolds and Richardson numbers are taken to ascertain laminar flow, Re = 50–250 and Ri = 0.1–100. The size of the porous layer is quantified by the thickness of the porous layer Hp = 0.25–1. The problem is studied for two cases of heat and species sources; the opposing case, when the active side is on the right, and assisting case, when the active side is on the left. Results reveal that for specified conditions, the triangular porous layer increases Nusselt and Sherwood numbers by 30% and 32%, respectively, more than the horizontal porous layer. The opposing case gives maximum convective heat transfer, where for Ri = 0.01, the Nusselt number is higher by 61% and 134% for Re = 50 and 250, respectively, while for Ri = 100, the percentages increase are 67% and 43%.

Wavelength-Tunable Monolithically Integrated Chaotic Semiconductor Laser

Chaos wavelength division multiplexing is a key technology to solve incompatibility between chaos secure communication and large capacity fiber data transmission. However, the existing integrated chaotic semiconductor laser can not achieve wavelength tuning in a large range. Here, a wavelength-tunable chaotic semiconductor laser chip has been designed and fabricated. The chip consists of a gain section, a distributed Bragg reflector (DBR) grating section, a semiconductor optical amplifier (SOA) section, and a phase section. With the optical feedback from the reflective facet of the phase section, and the mode-beating of composite cavities, the chip emits chaotic laser. By adjusting the current of DBR grating, the wavelength can be tuned in a range of 13.4 nm, and the central wavelength can be fine-tuned by adjusting the current of the phase region. Moreover, the evolution from periodic oscillation to chaotic oscillation is presented with the variation of the SOA current. The distribution of dynamics and the variation of bandwidth induced by the SOA current and the gain current are investigated. This work explores a wavelength-tunable chaotic semiconductor laser for the wavelength division multiplexing in the application of large capacity chaotic secure optical communications.

1.7 &amp;lt;bold&amp;gt;&amp;mu;&amp;lt;/bold&amp;gt;m self-synchronized picosecond pulsed random Raman fiber laser

Aiming at the structural complexity of the current 1.7 μm band short pulse lasers, we propose and implement a self-synchronized picosecond pulsed random Raman fiber laser. The half-open Raman cavity based on random distributed feedback is pumped by a 1 578 nm pulsed fiber laser to achieve a picosecond pulse output with a central wavelength of 1 695 nm and an average power of 224 mW. The composite cavity formed by distributed Rayleigh scattering automatically satisfies the synchronous pumping condition without the need for precise matching of cavity length or complex feedback control in the system. By inserting a wavelength division multiplexer in the cavity, the random sub-cavity noise is suppressed and the stability of the output pulse is improved. To the best of our knowledge, this is the first realization of a random pulse fiber laser operating at 1.7 μm, which can be widely used in bioimaging and material processing. <fig fig-type="abstract-image" id="F1" orientation="portrait" position="float"><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="1000-2618-2022-39-4-363/7A9ED982-4F80-49df-B290-3AA8759A767B-F001.jpg"/></fig>

Parametric-amplification-induced nonreciprocal magnon laser.

We theoretically propose a scheme to achieve all-optical nonreciprocal magnon lasing action in a composite cavity optomagnonical system considering of a yttrium iron garnet sphere coupled to a parametric resonator. The magnon lasing behavior can be engendered via the magnon-induced Brillouin scattering process in the cavity optomagnonical system. By unidirectionally driving the χ(2)-nonlinear resonator with a classical coherent field, the squeezed effect occurs only in the selected direction due to the phase-matching condition, resulting in asymmetric detuning between the two resonators, which is the physical mechanism to generate a nonreciprocal magnon laser. We further examine the gain factor and power threshold of the magnon laser. Moreover, the isolation rate can reach 21 dB by adjusting the amplitude of the parametric amplification. Our work shows a path to obtain an all-optical nonreciprocal magnon laser, which provides a means for the preparation of a coherent magnon laser and laser protection.

Molecular insights into biogenesis of glycosylphosphatidylinositol anchor proteins

Eukaryotic cells are coated with an abundance of glycosylphosphatidylinositol anchor proteins (GPI-APs) that play crucial roles in fertilization, neurogenesis, and immunity. The removal of a hydrophobic signal peptide and covalent attachment of GPI at the new carboxyl terminus are catalyzed by an endoplasmic reticulum membrane GPI transamidase complex (GPI-T) conserved among all eukaryotes. Here, we report the cryo-electron microscopy (cryo-EM) structure of the human GPI-T at a global 2.53-Å resolution, revealing an equimolar heteropentameric assembly. Structure-based mutagenesis suggests a legumain-like mechanism for the recognition and cleavage of proprotein substrates, and an endogenous GPI in the structure defines a composite cavity for the lipid substrate. This elongated active site, stemming from the membrane and spanning an additional ~22-Å space toward the catalytic dyad, is structurally suited for both substrates which feature an amphipathic pattern that matches this geometry. Our work presents an important step towards the mechanistic understanding of GPI-AP biosynthesis.

High-power tunable dual-wavelength diode laser with a composite external cavity

A high-power tunable dual-wavelength composite external cavity architecture obtained by means of a holographic grating and a volume Bragg grating is proposed and demonstrated. The tunable frequency difference of the dual-wavelength output is from 0.41 THz to 3.89 THz. We obtain an output power of 2.1 W when the frequency difference is 1.86 THz. The side-mode suppression ratio of more than 29 dB is suppressed over the entire tunable dual-wavelength output range. The two corresponding wavelengths of the dual-wavelength output basically maintain the same intensity with the smallest power difference of only 0.10%.

Quantifying composite restoration removal and cavity re-preparation using novel region-specific volumetric analysis

ObjectivesThis in-vitro study investigated the effect of 400–405 nm light used during removal of a composite restorations on volume of tooth tissue removed iatrogenically (IATR) and the volume of residual composite. MethodsThirty unrestored premolar teeth obtained via a university tissue bank were evenly allocated to test and control groups; material removal with and without violet light. Three clinicians (blinded to the protocol) prepared class V buccal cavities in the teeth. The teeth were scanned using CEREC Omnicam and reallocated to another clinician prior to restoration and rescanning. The teeth were reallocated, and the restorations were removed prior to rescanning.Volumetric scan data was obtained on: changes in cavity volume; the volume of IATR; the volume of residual composite. Data were analysed using Shapiro-Wilk and Kruskal–Wallis tests to a significance of p<0.05. ResultsData showed that there is more IATR when the light was used with mean volume CAV2-over cut of (3.4 mm3, SD 4.22) whereas less IATR was seen when the light was not used (1.2 mm3, SD 1.00), (p<0.05). Data also showed that there is no significant difference in the overall volume of resin composite left when the light was used or not (p> 0.05). However when the light was used, less resin composite material was left around the margins of the cavities when compared to the no light group. SignificanceThis novel region-specific cavity analysis method reveals patterns of iatrogenic damage and retained composite which may hold clinical relevance. The use of violet light may result in more complete removal of composite at margins, but also increase IATR. Further research using the novel method is required to ascertain the repeatability and clinical significance of findings.

One-sided composite cavity on an optical nanofiber for cavity QED

We demonstrate a one-sided cavity on an optical nanofiber (ONF) using a composite method. The one-sided composite cavity is created by mounting an asymmetric defect mode grating on an ONF. We design the one-sided composite cavity on an ONF to enhance channeling efficiency into one side of ONF while operating from under- to critical- and over-coupling regimes using numerical simulations. Experimentally, we demonstrate coupling characteristics of the one-sided composite cavity, showing good correspondence with simulation results.

Characterization of mode field distribution in optical Fabry-Perot cavity based on nanofiber

The composite cavity optomechanical system combining optical Fabry-Perot (F-P) cavities, particles, and micro/nano mechanical oscillators is becoming more significant in the researches and applications of the fundamental physics, quantum information processing, and precision measurement. Characterizing the mode field distribution of optical F-P cavity is significant prior to the application of optical F-P cavity. In this paper, we propose and demonstrate a method to measure the waist of an optical F-P cavity and to characterize the mode field distribution of the optical F-P cavity by using a nanofiber nondestructively. In experiment, a nanofiber is placed in the mode of the optical F-P cavity with a fineness of around 1500. The optical F-P cavity is composed of two mirrors each with high reflectivity of 99.8%. The radius of curvature of the each mirror is 50 mm. The cavity length is (&lt;inline-formula&gt;&lt;tex-math id="M1"&gt;\begin{document}$ 80 \pm 4 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221538_M1.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221538_M1.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;) mm. The nanofiber is fabricated from a single-mode fiber by the flame-brush method. The nanofiber diameter is around 440 nm. The transmission spectra of the optical F-P cavity are measured by scanning the cavity length. The free spectrum ranges and the inner cavity losses can be obtained from the transmission spectra. First, the influence of the nanofiber on the optical F-P cavity fineness is investigated. The fineness as a function of nanofiber position along the radial direction of the optical F-P cavity is measured. The fineness caused by the nanofiber decreases to a minimum value of about 240. Second, it is investigated that the optical F-P cavity inner loss caused by the nanofiber as a function of the nanofiber position along the radial direction of the optical F-P cavity when the nanofiber is placed at the waist of the optical F-P cavity. The inner loss of the optical F-P cavity caused by the nanofiber is related to the intensity distribution of the optical F-P cavity mode field, which is predicted theoretically. Thus, by making the Gaussian fitting of the optical F-P cavity inner loss as a function of the nanofiber position, we can obtain a waist radius of the optical F-P cavity to be (&lt;inline-formula&gt;&lt;tex-math id="M2"&gt;\begin{document}$ 72 \pm 1 $\end{document}&lt;/tex-math&gt;&lt;alternatives&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221538_M2.jpg"/&gt;&lt;graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="23-20221538_M2.png"/&gt;&lt;/alternatives&gt;&lt;/inline-formula&gt;) μm. This is in good agreement with the theoretical calculation. Finally, the mode field distribution of the optical F-P cavity along the cavity axis is characterized. This method can be used for precisely controlling the coupling between the particles on the surface of nanofiber and optical F-P cavity. Besides, this method provides a good platform for studying the hybrid optomechanical system combining cavities, photons and quantum emitters.

Michelson interferometer composite cavity fiber laser sensor with radio frequency interrogation

Michelson interferometer composite cavity fiber laser sensor with radio frequency interrogation

Sensitivity-improved fiber optic current sensor based on an optoelectronic oscillator utilizing a dispersion induced microwave photonic filter.

An optoelectronic oscillator (OEO)-based fiber optic current sensor (FOCS) with greatly improved sensitivity is proposed and experimentally demonstrated. A microwave photonic filter (MPF) induced by the dispersion effect of a linearly chirped fiber Bragg grating (LCFBG) is used to select the frequency of the OEO oscillating signal. A two-tap MPF formed by a polarization multiplexed composite cavity is cascaded to achieve a stable single mode oscillation. When the current changes, the magneto-optic phase shift induced by Faraday effect will be introduced between the left and right circularly polarized lights transmitted in the reflective sensing unit. The magneto-optic phase shift is converted to the phase difference between the optical carrier and sidebands through a LiNbO3 Mach-Zehnder modulator. This phase difference is the decisive factor for the center frequency of the cascaded MPF as well as the oscillating frequency. Therefore, the current can be measured in the microwave frequency domain, which can improve the interrogation speed and accuracy to a large extent. The experimental results show that the oscillating frequency shifts up to 407.9 MHz as the current increases by 1 A.

Evaluation of Cervical Margin Relocation for CAD/CAM Zirconia Crowns Using Different Composite Resin Materials and Cavity Designs: Marginal Gap and Microleakage

This study evaluated the effect of the material and the extension of the relocated margin on the marginal adaptation of the extra coronal restoration and microleakage at the tooth/resin interface after thermo-mechanical cyclic loading. Materials and methods: 196 teeth were divided into six groups according to type of cavity design and build-up restoration. All the groups received a standardized MO cavity preparation. The gingival seat was located 2 mm above the CEJ. Group I was without any modification and restored with direct composite. For Group II, III and IV the gingival seat extended 2mm below the CEJ and restored with direct, flowable, indirect composite respectively. Group V had MOD cavity where the proximal boxes had the same criteria of the mesial preparation of Groups II-IV. Samples of Group VI received the same preparation as Groups II, III and IV but was extended another 4mm in the buccal direction. Groups V and VI were restored with direct composite. Margin gap and microleakage scores were evaluated after cyclic loading Results: Group VI and IV showed the highest mean margin value compared to different cavity designs and materials used for CMR respectively, however within clinically acceptable range. Group III showed the highest microleakage scores. Conclusions: The use of CMR with single or multiple narrow cavities is more favorable than with wide cavities. CMR is a logical option in teeth with deep proximal cavities that needs to be crowned.

Broadly tunable, intracavity injection-seeded, hybrid optical parametric oscillator

We report a novel, to the best of our knowledge, approach for injection seeding of pulsed optical parametric oscillators (OPOs), which can provide spectral control over the full tuning range. Bandwidth reduction down to single-mode operation is realized across the pulsed tuning range by deploying a hybrid design, where a continuous-wave (cw) OPO injection seeds the pulsed OPO in a single composite cavity. By exploiting two identical MgO-doped periodically poled lithium niobate crystals, the hybrid OPO provides signal pulses with a single-frequency linewidth as narrow as 7.2 MHz across 1510-1677 nm. The effect of cw injection seeding on pulsed OPO operation is also confirmed by reduced rise time, increased pump depletion, major reduction in threshold, and substantial enhancement in output power and extraction efficiency.

Suppressing stimulated Raman scattering by adopting a composite cavity in a narrow linewidth fiber oscillator

The master oscillator power amplifier structure has been widely employed to realize high-power and narrow-linewidth output in fiber lasers. However, the stimulated Raman scattering (SRS) effect would appear in high-power operation and even become an important limitation on further power scaling, especially when the seed lasers are based on a fiber Bragg grating (FBG) pair. In order to improve SRS suppressing ability, a composite cavity structure was demonstrated by employing an additional wide-bandwidth low-reflectivity FBG outside the conventional oscillator. After passing through a piece of 50 m SMF-28e fiber, thanks to the improved temporal stability of the composite oscillator, the proportion of Raman Stokes light dropped dramatically compared with the proportion in a conventional fiber oscillator. This composite cavity design could provide a simple and compact approach for SRS suppression in a high-power narrow-linewidth fiber laser system.

2.1 μm self frequency conversion optical parameter oscillator based on Nd3+ doped MgO:PPLN

A 2.1 μm integrated self frequency conversion optical parametric oscillator which based on Nd3+ doped MgO:PPLN with intra-cavity acousto-optic Q-switched is reported. Under different thermal focal lengths of Nd3+ doped MgO:PPLN, the focusing parameter ratio of 1084 nm and 2168 nm and the spot radius of 1084 nm are simulated, and the optimal parameters of the composite resonant cavity are determined. According to the quasi-phase matching principle, 1093 nm is effectively suppressed by the design of the composite resonator, and a single-wavelength output of 1084 nm is obtained. The 2.1 μm self frequency conversion optical parametric oscillator with Nd3+ doped MgO:PPLN is realized for the first time, the output power is 1.21 W, the highest down-conversion efficiency from 1084 nm to 2.1 μm is 15.1%. The pulse width of 2168 nm is around 7.8 ns when the repetition rate is 40 kHz.

High sensitivity interrogation system of fiber Bragg grating sensor with composite cavity fiber laser

A high sensitivity interrogation system of fiber Bragg grating (FBG) sensor with composite cavity fiber laser is proposed and experimentally demonstrated. The FBG is used as a sensing grating and the chirped fiber Bragg grating (CFBG) is used as a reference grating. Both are placed at the end of the fiber Michelson interferometer (MI) acts as the two arms mirrors and form a composite cavity of the fiber laser. The longitudinal modes generated by the composite cavity fiber laser are superimposed on each other to generate envelopemodulation of the beat frequency signal (BFS) which depends on the optical path difference between the two arms. The wavelength change of the sensor FBG can be obtained by measuring the BFS drift causedby the arm length change of the MI. In our scheme, the wavelength change of sensor FBG is converted into arm length change by using CFBG and finally into fiber laser BFS drift. The system has a simple structure, low cost, and high sensitivity.

Effect of 940nm laser diode irradiation prior to bonding procedure on postoperative sensitivity following class II composite restorations: a split-mouth randomized clinical trial.

The aim of this study was to evaluate the effect of 940nm laser diode on class II composite cavities prior to bonding and restoration process on the postoperative sensitivity (POS). Thirty patients with two bilateral premolars with mesio or disto-occlusal carious lesions were evaluated. In each patient, the teeth were randomly divided into the control and laser groups. After cavity preparation and isolation and before the bonding process, the laser group was subjected to 940nm irradiation (Epic 10, Biolase, USA) by 400μ tip continuously at 100mW with 398J/cm2 energy density of tip, which was applied for 5s at a distance of 2mm on the axial wall of the cavity. In the control group, irradiation was performed by using the aiming beam. Access cavity was then restored with a composite resin. Cold sensitivity was measured using a cold spray application on the middle third of teeth buccal surface at baseline (before the intervention), 1, 14, and 30days after the restoration by visual analog scale (VAS) criteria. The mean Friedman and Wilcoxon signed-rank tests were used for data analysis. It was shown that in both laser and control groups, the VAS was significantly decreased at all times compared to the baseline (p≤0.05). There was no statistically significant difference between the mean VAS of two groups at baseline and first day (p≤0.05), but at 14 and 30days after the intervention, it was significantly lower in the laser group (p≤0.05). The results of this study demonstrated that the cavity pretreatment with laser diode (940nm) effectively reduces the postoperative sensitivity in class II composite restorations.

Research on the effect of UHMWPE cavity protection board on rapid enhancement of wall anti-blast performance

In view of the high cost and self-importance of traditional explosion-proof walls, a fiber composite material cavity protective board made of UHMWPE as a matrix is proposed to protect the walls of general civil buildings to achieve rapid enhancement in response to sudden terrorist attacks. Based on LS-DYNA finite element analysis, the response of the protective board and wall under the impact of the explosion is analyzed. By setting different key parameters such as equivalent weight, burst distance, presence or absence of protective structure, the damage to the wall, the protective effect of the protective board and its own performance characteristics are discussed. The results show that the externally arranged composite material protection board can effectively attenuate and absorb the overpressure and energy generated by the explosion shock wave, and significantly reduce the displacement and deformation of the wall, and it also has excellent performance in its own energy absorption and deformation resistance. But there is a certain safety protection distance under different equivalents.

Double pumped composite cavity 501 nm cyan laser with tunable injection power ratio

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed