Postoperative Sleep Quality of Insomnia Patients After TIVA Anesthesia: A Prospective Study.

PURPOSE: The purpose of this study is to observe the postoperative sleep quality of insomnia patients undergoing laparoscopic gynecologic oncology surgery after total intravenous anesthesia. DESIGN: Prospective study. METHODS: We conducted a prospective, observational study in our hospital. All patients underwent propofol-remifentanil anesthesia without other sedative medications before or during the operation. Pittsburgh Sleep Quality Index (PSQI) scores of the baseline value, night-1 (the first night after surgery), night-3, night-5, and night-30 were observed. FINDINGS: Sixty-nine female insomnia patients were allocated based on the results of the PSQI and the diagnostic criteria of insomnia. The PSQI global scores were respectively 6 (5-8), 5 (4-6), 5 (3-6), and 6 (5-7) on night-1, night-3, night-5, and night-30, significantly lower than the baseline 7 (6-8) (P < 0.05). The 5 components (subjective sleep quality, sleep latency, sleep duration, sleep efficiency and daytime dysfunction) had significant changes at different postoperative time points (P < 0.05). The daytime dysfunction could also be improved 1 month after the surgery (P < 0.05). In contrast, the variations of sleep disturbance and use of sleep medication had no statistical differences. CONCLUSIONS: The sleep quality of female patients with insomnia was improved on the first night after surgery in the sides of sleep latency and daytime dysfunction, and the improvement could also be obtained 1 month after propofol-remifentanil general anesthesia.

Polarization-independent and ultra-sensitive biosensor with a one-dimensional topological photonic crystal.

Optical biosensor, which perceptively captures the variety of refractive index (RI) of the surrounding environment, has great potential applications in detecting property changes and types of analytes. However, the disequilibrium of light-matter interaction in different polarizations lead to the polarization-dependence and low sensitivity. Here, we propose a polarization-independent and ultrasensitive biosensor by introducing a one-dimensional topological photonic crystal (1D TPhC), where two N-period 1D photonic crystals (PhC1 and PhC2) with different topological invariants are designed for compressing the interaction region of the optical fields, and enhancing the interaction between the light and analyte. Since the strong light-matter interaction caused by the band-inversion is polarization-independent, the biosensor can obtain superior sensing performance both for TE and TM polarization modes. The sensitivity and Figure of Merit (FOM) of the designed biosensor are 1.5677×106 RIU-1 (1.3497 × 106 RIU-1) and 7.8387×1010 RIU-1deg-1 (4.4990×1010 RIU-1deg-1) for TM (TE) polarization mode, which performs two orders of magnitude enhancement compared with the reported biosensors. With the protection of the topological edge state, this biosensor has high tolerance to the thickness deviations and refractive index (RI) variations of the component materials, which can reduce the requirements on fabrication and working environment. It is anticipated that the proposed biosensor possesses excellent sensing performances, may have great potentials in environmental monitoring, medical detection, etc.

Theoretical Insights into Energy Absorption and Charge Draining during Field Evaporation Assisted by Femtosecond Laser Pulses.

Manipulation of laser-assisted field evaporation taking place at a sub-picosecond time scale relies on a full understanding of the dynamics at a microscopic level. We use first-principles methods to investigate the mechanism of energy absorption and charge draining during fast evaporation of silicon in a high electrostatic field with ultrafast-laser illumination. The results show that laser energy absorption to trigger field evaporation can be described by an effective cross section, which depends on the photon frequency and the static field strength. The cross section is not affected by pulse duration or laser intensity, indicating that the absorption is first-order. It is found that the charge state of the evaporating ion fluctuates due to the collective excitation of electrons. The average charge state does not depend on laser parameters but only on the static field strength, in agreement with experimental observations. Our work provides theoretical insights into the manipulation of modern atom probe tomography and other ultrafast-laser-induced phenomena in high electric fields.

GlideScope® versus C-MAC®(D) videolaryngoscope versus Macintosh laryngoscope for double lumen endotracheal intubation in patients with predicted normal airways: a randomized, controlled, prospective trial.

BACKGROUND: The double lumen endotracheal tube (DLT) is the most widely-used device for single lung ventilation in current thoracic anesthesia practice. In recent years, the routine application of the videolaryngoscope for single lumen endotracheal intubation has increased; nevertheless there are few studies of the use of the videolaryngoscope for DLT. We wondered whether there were benefits to using the videolaryngoscope for DLT placement in patients with predicted normal airways. Therefore, this study was designed to compare the performances of the GlideScope®, the C-MAC®(D) videolaryngoscope and the Macintosh laryngoscope in DLT intubation. METHODS: This was a randomized, controlled, prospective study. We randomly allocated 90 adult patients with predicted normal airways into three groups. All patients underwent routine anesthesia using different laryngoscopes according to group allocation. We compared DLT insertion times, first-pass success rates, numerical rating scales (NRS) of DLT delivery and DLT insertion, Cormack-Lehane degrees (C/L), hemodynamic changes and incidences of intubation complications. All outcomes were analyzed using SPSS13.0. RESULTS: Compared with the GlideScope, the Macintosh gave shorter times for DLT insertion (median: 96 (IQR: 51 [min-max: 62-376] s vs 73 (26 [48-419] s, p = 0.003); however, there was no difference between the Macintosh and C-MAC(D) (p = 0.610). The Macintosh had a significantly higher successful first attempt rate than did the GlideScope or C-MAC(D) (p = 0.001, p = 0.028, respectively). NRS of DLT delivery and insertion were significantly lower in the Macintosh than in the others (p < 0.001). However, the C/L degree in the Macintosh was significantly higher than in the others (p < 0.001). The incidences of oral bleeding, hoarseness, sore throat and dental trauma were low in all groups (p > 0.05). There were no significant differences in DLT misplacement, fiberoptic time or hemodynamic changes among the groups. CONCLUSIONS: Compared with the Macintosh laryngoscope, the GlideScope® and C-MAC®(D) videolaryngoscopes may not be recommended as the first choice for routine DLT intubation in patients with predicted normal airways. TRIAL REGISTRATION: The study was prospectively registered at the Chinese Clinical Trial Registry (no. ChiCTR1900025718); principal investigator: Z.L.H.; date of registration: September 6, 2019.

Ultra-compact high-sensitivity plasmonic sensor based on Fano resonance with symmetry breaking ring cavity.

Miniaturizing optical devices with desired functionality is a key prerequisite for nanoscale photonic circuits. Based on Fano resonance, an on-chip high-sensitivity sensor, composed of two waveguides coupling with a symmetry breaking ring resonator, is theoretically and numerically investigated. The established theoretical model agrees well with the finite-difference time-domain simulations, which reveals the physics of Fano resonance. Differing with the coupled cavities, the Fano resonance originates from the interference between symmetry-mode and asymmetry-mode in a single symmetry-broken cavity. The spectral responses and sensing performances of the plasmonic structure rely on the degree of asymmetry of cavity. In particular, the plasmonic sensor can detect the refractive index changes as small as 10-5, and the figure of merit (FOM) of symmetry-breaking cavity structure is 17 times larger than that of symmetrical cavity system. Additionally, the sensitivity to temperature of ethanol analyte achieves 0.701 nm/○C. Compared with the coupled cavities, the on-chip high-sensitivity sensor using a single cavity is more compact, which paves the way toward highly integrated photonic devices.

Confined surface plasmon of fundamental wave and second harmonic waves in graphene nanoribbon arrays.

The confined surface plasmon of fundamental wave and second harmonic wave (SHW) are investigated in graphene grating structure. The linear-optical absorption spectra with various fermi energy and carrier mobility are investigated with the finite difference time domain (FDTD) simulations and coupled mode theory (CMT). Based on the CMT, a theoretical model for the graphene grating is established to study the spectrum features of fundamental wave. The lifetimes of linear-optical resonant modes in theoretical model are investigated through the theoretical fitting of exact values in simulation, which are tunable with both the fermi energy and carrier mobility. We also have investigated the second-order nonlinearity of graphene grating by introducing the second-order nonlinear source. The proposed configuration and method are useful for research of the absorption, local field enhancement factor, lifetime of light, and nonlinear optical processes in highly integrated graphene photoelectric devices.

Divergent Effect of Dezocine, Morphine and Sufentanil on Intestinal Motor Function in Rats.

BACKGROUND: Opioid induced bowel dysfunction is the most common side effect of preoperatively administrated morphine, fentanyl and its derivative. However, the influence of dezocine on intestinal mobility is rarely reported. This study was designed to investigate the effects of dezocine, morphine and sufentanil on both intestinal smooth muscle contraction and propulsion in rats. METHODS: Contractile tension and frequency of isolated rat small intestine smooth muscle were measured using tension transducer after incubation with different concentrations of dezocine, morphine and sufentanil. The propulsive rate of methylene blue in rat intestinal tract was measured 30 minutes after intraperitoneal injection of morphine, sufentanil and dezocine. Percent of change in contractile tension and contraction frequency compared to baseline level were calculated to evaluate muscle contraction. Propulsive rate of methylene blue was calculated as the percentage of methylene blue moving distance in intestinal tract compared to the length of the small intestine. RESULTS: Morphine and sufentanil significantly increased the contractile tension of isolated small intestine smooth muscle at high doses. The contraction frequency did not change significantly among the 3 tested doses. Increasing the dose of dezocine from 1.7 mg.L(-1) to 10.2 mg.L(-1) did not change either the contractile tension or the contraction frequency. The propulsive rate of methylene blue in intestinal tract was significantly decreased after the treatment with morphine, sufentanil and dezocine (45.6%, 43.7%, and 42.1% respectively) compared to control group(57.1%), while the difference among the 3 drug groups were not significant. CONCLUSION: Morphine and sufentanil may dose dependently increase the contractile tension and contraction ability of isolated rat small intestine smooth muscle, while dezocine has no significant effect on intestine smooth muscle contraction. However, all these opioids might impair small intestinal propulsion.

Second-order nonlinearity in triangular lattice perforated gold film due to surface plasmas resonance.

We have studied the excitation second-order nonlinearity through a triangular lattice perforated gold film instead of square lattice in many papers. Under the excitation of surface plasmas resonance effect, the second order nonlinearity exists in the noncentrosymmetric split-ring resonators arrays. Reflection of fundamental frequency wave through a triangular lattice perforated gold film is obtained. We also described the second harmonic conversion efficiencies in the second order nonlinear optical process with the spectra. Moreover, the electric field distributions of fundamental frequency above the gold film region are calculated. The light propagation through the holes results in the enhancement of the second order nonlinearity including second harmonic generation as well as the sum (difference) frequency generation.

Capnographic monitoring reduces hypoxia incidence in older patients undergoing gastrointestinal endoscopy under propofol sedation: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Hypoxia is a very common adverse event that occurs during gastrointestinal endoscopy under sedation, especially in older patients, owing to limited reservation of heart, brain, lung, and other organs. Prolonged or severe hypoxia can cause ischemia of the coronary artery and permanent nervous system damage, and even result in death. Hence, it is imperative to reduce or prevent hypoxia during gastrointestinal endoscopy under sedation in older patients. Although several oxygen delivery methods would reduce hypoxia during this procedure, early detection of respiratory depression and early administration of intervention would be the best method to reduce or even confirm the hypoxia. Capnographic monitoring is reportedly more sensitive for detecting respiratory depression before the onset of hypoxia than the current clinical routine monitoring of pulse oxygen saturation; however, its effect is controversial. Therefore, in this study, we aimed to improve the safety of gastrointestinal endoscopy under sedation in older patients. METHODS: A multicenter, randomized, single-blind, two-arm parallel-group, controlled with an active comparator, interventional superiority clinical trial will be conducted to evaluate the impact of an additional capnographic monitoring-based intervention on the incidence of hypoxia in older patients. Patients (n = 1800) scheduled for gastrointestinal endoscopy with propofol sedation will be randomly assigned to either a control or interventional arm, wherein standard or capnographic monitoring is implemented, respectively. DISCUSSION: This study primarily aims to examine whether an additional capnographic monitoring-based intervention can reduce the incidence of hypoxia in older patients during gastrointestinal endoscopy under propofol and sufentanil sedation. The results of this study may extensively impact gastrointestinal endoscopy under sedation and the development of associated guidelines. TRIAL REGISTRATION: ClinicalTrials.gov NCT05030870. Registered on September 1, 2021.

Green synthesis of CQDs for determination of iron and isoniazid in pharmaceutical formulations.

Camphor leaves were used as the precursor for the hydrothermal synthesis of carbon quantum dots. The preparation method is simple and rapid, and the raw material is environmentally friendly and easy to obtain. Without additional modification, the carbon quantum dots were used as fluorescent probes for the sensitive and selective detection of Fe3+ and isoniazid at different excitation wavelengths. For Fe3+, at the excitation wavelength of 320 nm, the ratio of fluorescence intensity of CQD solution after adding Fe3+ to CQD solution without Fe3+ addition, F/F0, and Fe3+ concentration showed a good linear relationship in the range of 2.72 × 10-5 to 1.00 × 10-4 mol L-1 (R2 = 0.9912), and the limit of detection was 8.16 µmol L-1. For isoniazid, at the excitation wavelength of 270 nm, the ratio of fluorescence intensity of CQDs solution with isoniazid to CQDs solution without isoniazid, F/F0, and isoniazid concentration showed good linear relationships in the range of 3.81 × 10-6 to 1.00 × 10-5 mol L-1 (R2 = 0.9941) and 1.00 × 10-5 to 2.10 × 10-4 mol L-1 (R2 = 0.9910) respectively, and the limit of detection was 1.14 µmol L-1. A fluorescence method for the determination of Fe and isoniazid content was proposed. The method has been used to detect iron in iron supplement tablets and isoniazid in isoniazid tablets with satisfactory results.

Two Fe(III)/Eu(III) Salophen complex-based optical sensors for determination of organophosphorus pesticide monocrotophos.

Monocrotophos (MP), an organophosphorus pesticide, poses a serious threat to human health, so a rapid and simple technique is needed to detect it. In this study, two novel optical sensors for MP detection were created using the Fe(III) Salophen complex and Eu(III) Salophen complex, respectively. One sensor is an Fe(III) Salophen complex (I-N-Sal), which can bind MP selectively and form a supramolecule, resulting in a strong resonance light scattering (RLS) signal at 300 nm. Under the optimum conditions, the detection limit was 30 nM, the linear range was 0.1-1.1 µM, the correlation coefficient R2 = 0.9919, and the recovery rate range was 97.0-103.1%. Interaction properties between the sensor I-N-Sal and MP and the RLS mechanism were investigated using density functional theory (DFT). And another sensor is based on the Eu(III) Salophen complex and 5-aminofluorescein derivatives. The Eu(III) Salophen complex was immobilized on the surface of amino-silica gel (Sigel-NH2) particles as the solid phase receptor (ESS) of MP and 5-aminofluorescein derivatives as the fluorescent (FL)-labeled receptor (N-5-AF) of MP, which can selectively bind the MP and form a sandwich-type supramolecule. Under the optimum conditions, the detection limit was 0.4 µM, the linear range was 1.3-7.0 µM, the correlation coefficient R2 = 0.9983, and the recovery rate range was 96.6-101.1%. Interaction properties between the sensor and MP were investigated by UV-vis, FT-IR, and XRD. Both sensors were successfully applied to the determination of MP content in tap water and camellia.

Opioid binding sites in human serum albumin.

BACKGROUND: Human serum albumin (HSA) is an important carrier for opioids. However, the locations of the binding sites remain unclear. In the present study, we have characterized opioid-HSA interactions using multiple biochemical and biophysical techniques to reveal: (a) the location of the binding site(s); (b) whether naloxone shares the binding site with morphine; and (c) whether opioid agonists share their binding site(s) with general anesthetics. METHODS: Elution chromatography to determine the global interactions and tryptophan intrinsic fluorescence to determine the localized interactions of opioids with HSA were used. Competition studies using isothermal titration calorimetry were used to determine the overlap of binding site(s) among opioid agonists, antagonists, and general anesthetics. An automatic docking calculation was used to predict the possible binding sites and to assess findings of the solution studies. RESULTS: For elution chromatography with immobilized HSA, the retention times of naloxone, morphine, and fentanyl were prolonged but shorter than that of propofol. The inhibition of tryptophan fluorescence by naloxone was not affected by morphine or fentanyl. The calorimetric heat profiles of propofol and halothane interaction with HSA were changed significantly, but not equally by morphine, naloxone, or fentanyl. Consistent with direct binding studies, docking results demonstrated that opioids share sites with general anesthetics; a distinct binding site for naloxone was revealed near the sole tryptophan in HSA that is not shared with morphine. CONCLUSIONS: The interaction of opioids with HSA is weak in comparison with propofol. Naloxone has a distinct binding site in HSA not shared with opioid agonists. Opioids share binding sites with general anesthetics in HSA.

Tunable Lifetime and Nonlinearity in Two Dimensional Materials Plasmonic-Photonic Absorber.

We investigate a framework of local field, quality factor and lifetime for tunable graphene nanoribbon plasmonic-photonic absorbers and study the second order and third order nonlinear optical response of surface plasmons. The energy exchange of plasmonic-photonic absorber occurs in two main ways: one way is the decay process of intrinsic loss for each resonant mode and another is the decay process of energy loss between graphene surface plasmon (GSP) mode and the external light field. The quality factor and lifetime of the plasmonic-photonic absorber can be obtained with using the coupled mode theory (CMT) and finite difference time domain (FDTD) method, which are effectively tunable with changing Fermi energy, carrier mobility and superstrate refractive index. The evolutions of total energy and lifetime of GSP are also shown, which are helpful for the study of micro processes in a two-dimensional material plasmonic-photonic absorber. The strongly localized fundamental field induces a desired increase of second harmonic (SH) wave and third harmonic (TH) wave. The manipulation of the quality factor and lifetime of the GSP makes graphene an excellent platform for tunable two-dimensional material plasmonic-photonic devices to realize the active control of the photoelectric/photothermal energy conversion process and higher harmonic generation.

Constructing a novel gene signature derived from oxidative stress specific subtypes for predicting survival in stomach adenocarcinoma.

Oxidative stress (OS) response is crucial in oncogenesis and progression of tumor. But the potential prognostic importance of OS-related genes (OSRGs) in stomach adenocarcinoma (STAD) lacked comprehensive study. STAD clinical information and transcriptome data were retrieved from the Gene Expression Omnibus and The Cancer Genome Atlas databases. The prognostic OSRGs were filtered via the univariate Cox analysis and OSRG-based molecular subtypes of STAD were developed using consensus clustering. Weighted gene co-expression network analysis (WGCNA) was subsequently conducted to filter molecular subtype-associated gene modules. The prognosis-related genes were screened via univariate and least absolute shrinkage and selection operator Cox regression analysis were used to construct a prognostic risk signature. Finally, a decision tree model and nomogram were developed by integrating risk signature and clinicopathological characteristics to analyze individual STAD patient's survival. Four OSRG-based molecular subtypes with significant diversity were developed based on 36 prognostic OSRGs for STAD, and an OSRGs-based subtype-specific risk signature with eight genes for prognostic prediction of STAD was built. Survival analysis revealed a strong prognostic performance of the risk signature exhibited in predicting STAD survival. There were significant differences in mutation patterns, chemotherapy sensitivity, clinicopathological characteristics, response to immunotherapy, biological functions, immune microenvironment, immune cell infiltration among different molecular subtypes and risk groups. The risk score and age were verified as independent risk factors for STAD, and a nomogram integrating risk score and age was established, which showed superior predictive performance for STAD prognosis. We developed an OSRG-based molecular subtype and identified a novel risk signature for prognosis prediction, providing a useful tool to facilitate individual treatment for patients with STAD.

Identification of ISCA1 as novel immunological and prognostic biomarker for bladder cancer.

Background: Iron-sulfur cluster assembly 1 (ISCA1) has a significant effect on respiratory complexes and energy metabolism. Although there is some evidence that ISCA1 gene expression impacts energy metabolism and consequently has a role in tumorigenesis and cancer metastasis in different types of malignancies, no systematic pan-cancer study of the ISCA1 has been conducted. As a result, we sought to investigate ISCA1's predictive value in 33 cancer types as well as its possible immunological function. Methods: We included the pan-cancer expression profile dataset and clinical data from the public database. Firstly, the single-sample Gene Set Enrichment Analysis (ssGSEa) approach was employed for analyzing the immune link in pan-cancer, while the limma package was utilized for analyzing the differential expression in cancer species. Subsequently, ciberport, MCP-counter, TIMER2, quanTIseq, and xCELL were employed for analyzing bladder cancer (BLCA)'s immune infiltration. Least absolute shrinkage and selection operator (Lasso) were employed for choosing the best gene to develop the immune risk scoring model. Results: ISCA1 gene expression was positively related to four immune signatures (chemokine, immunostimulator, MHC, and receptor) in BLCA. Samples of BLCA were sorted into two groups by the best cut-off of ISCA1 expression degree. The group with a high level of ISCA1 expression had a higher risk, suggesting that the ISCA1 gene was a risk factor in BLCA, and its high expression resulted in a poorer prognosis. Additionally, it was noted that ISCA1 was positively linked with these immune checkpoints. Moreover, there was a considerable positive link between ISCA1 and different immune properties in subgroups with different immune checkpoint inhibiting responses. Finally, an immune risk scoring model was made and it showed a better score in comparison to that of TIDE. Conclusion: ISCA1 can be a prognostic marker for a variety of cancers, particularly BLCA. Its high level of expression has a deleterious impact on the prognosis of BLCA patients. This strongly shows that ISCA1 is a significant prognostic factor for BLCA and that it could be used as a new prognostic detection target and treatment approach.

[Research on the photoelectric conversion efficiency of grating antireflective layer solar cells].

A numerical investigation of the effect of grating antireflective layer structure on the photoelectric conversion efficiency of solar cells was carried out by the finite-difference time-domain method. The influence of grating shape, height and the metal film thickness coated on grating surface on energy storage was analyzed in detail. It was found that the comparison between unoptimized and optimized surface grating structure on solar cells shows that the optimization of surface by grating significantly increases the energy storage capability and greatly improves the efficiency, especially of the photoelectric conversion efficiency and energy storage of the triangle grating. As the film thickness increases, energy storage effect increases, while as the film thickness is too thick, energy storage effect becomes lower and lower.

Second-harmonic generation from metal-film nanohole arrays.

The roles of surface plasmon resonance and localized resonances in second-harmonic generation are investigated in a noncentrosymmetrical metallic film with a periodic subwavelength nanohole array. By using a recently developed microscopic classical theory and a three-dimensional finite-difference time-domain algorithm, numerical results show that the second-harmonic intensity is a function of the polarization and wavelength of incident waves. A peak of the second-harmonic intensity is achieved when the incident wave is along the direction perpendicular to the x-axis of nanoholes, which corresponds to the maximal extraordinary optical transmission. Meanwhile, the second harmonic is found to correlate with the group delay of incident waves.

Lifetime and nonlinearity of modulated surface plasmon for black phosphorus sensing application.

Black phosphorus surface plasmon (BPSP) is a new promising candidate material for electromagnetic field confinement at the subwavelength scale. Here, we theoretically investigated the light confinement, second-order nonlinearity and lifetimes of tunable surface plasmons in nanostructured black phosphorus nanoflakes with superstrates. The grating structure can enhance the local optical field of the fundamental wave (FW) and second harmonic wave (SHW) due to the surface plasmon resonance. Based on the coupled mode theory (CMT), a theoretical model for the nanostructured black phosphorus was established to study the spectrum features of FW. The lifetimes of the plasmonic resonant modes were investigated with the finite difference time domain (FDTD) simulations and CMT. Since the permittivity of black phosphorus depends on its Fermi energy and electron scattering rate, the lifetimes of plasmonic absorption modes are tunable with both the Fermi energy and scattering rate. The intensity, wavelengths and spectral width of BPSP resonance modes and their lifetimes can be precisely controlled with the Fermi energy, scattering rate, side length and refractive index of the superstrate. The sensitivity is described by varying the refractive index of the superstrate such as an aqueous solution. We have introduced a second-order nonlinear source to investigate the SHW of nanostructured black phosphorus. This paper presents the corner/edge energy distribution and the tunable lifetime of BPSP as well as their unprecedented capability of photon manipulation for second-order nonlinearity within the deep subwavelength scale. The configuration and method are useful for research of the absorption, lifetime of light and nonlinear optical processes in black phosphorus-based optoelectronic devices, especially the modulation and sensing applications.

Strong focusing properties and far-field focus in the two-dimensional photonic-crystal-based concave lens.

We have demonstrated that the strong and far-field focusing of a point source and a plane wave in a two-dimensional photonic-crystal-based concave lens by the use of the standard finite-difference time-domain simulations. The effect of the distance between the point source and the lens on the focusing is discussed. The far-field focus of a plane wave is shown. In addition, a plane wave is formed with placing the source at the focus point. According to the calculation, the strong and good quality far-field focusing of the transmitted wave, explicitly following the well-known wave beam negative refraction law, can be realized. Moreover, the spatial frequencies information of the Bloch mode in multiple Brillouin zones is investigated in order to indicate the wave propagation in two different regions.

[Defect modes in one-dimensional comblike photonic crystals].

The photonic band structures and the effect of defect states on photonic band gap in a comblike waveguide geometry which were made of dangling side branches grafted periodically along an infinite monomode waveguide were investigated in this paper. It was discovered that the photonic forbidden bands originates from both the periodicity of the system and the resonance states of the grafted branches. By removing or inserting some defect branches in the star waveguide of finite number of grafted branches, the localized states appear in the transmission spectrum as very narrow peaks. The behavior of the localized states was analyzed as the functions of the length, the position and the number of the defective branches.