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Background: This research aims to investigate the expressions and clinical significance of inflammatory factors in the synovial fluid of the meniscus degeneration with knee osteoarthritis (OA). Methods: A total of 100 patients with meniscus degeneration in knee OA were divided into into stage II and III groups based on MRI imaging. The expressions of inflammatory factors including interleukin-1β (IL-1β), IL-17, tumor necrosis factor-α (TNF-α) and tumor growth factor-β1 (TGF-β1) in the knee joint fluid were determined by means of an ELISA and chemiluminescence assay. International general Lysholm score and correlation between the levels of four cytokines were further analyzed.Results: Compared with stage II group, patients in stage III group had significantly increased levels of IL-1β in the synovial fluid along with increases in TNF-α (P P PPConclusions: The high expression levels of IL-1β, TNF-α and IL-17, and the low expression levels of TGF-β1 in knee joint fluid are related to the severity of meniscus injury in patients with knee OA. These cytokines are associated with the pathological development of knee injury and ultimately lead to the decline of knee joint function.

Background The diagnosis, treatment and efficacy evaluation of anterior cruciate ligament (ACL) remains controversial. This research aims to investigate the underlying mechanism of partial ACL injuries to the meniscus degeneration in rabbit knee. Methods Sixty New Zealand, white rabbits were randomly divided into three groups: the anteromedial bundle (AMB) splitting, the posterolateral bundle (PLB) splitting and a control group. Finally, eight rabbits were sampled randomly on the second, fourth and eighth weeks respectively. We observed the typical form of the meniscus through HE staining. Expressions of inflammatory factors including interleukin-1β (IL-1β) and IL-17 in the knee joint fluid were determined by means of an ELISA. Analysis of the mRNA expressions of MMP-13 was performed to evaluate the inflammatory mediators in the pathogenesis of the meniscus. Results HE staining results showed that the surface was rough and the tissues were loose displaying collagen fibers of varying thickness. Both IL-1β and IL-17 in the synovial fluid, and the positive rate of MMP-13 in addition to MMP-13 mRNA showed a demonstrable increase treads from the 2nd to the 8th week. The significant difference was found ( P

The traditional method for determining mixing and compaction temperatures of asphalt binders, such as Brookfield viscosity test, often yields excessively high temperatures when used in many modified asphalts, and underestimates the temperature decreasing effect of the additives when used in warm-mixing asphalts. This study proposed a new viscosity measurement method, namely rotational plate viscosity (RPV) testing, to overcome these issues. The new method uses a Dynamic Shear Rheometer (DSR) with a 25-mm-diameter parallel plate geometry and a fixed shear rate 40 s−1 to measure the viscosity-temperature curve of modified asphalts, which minimizes the effect of the shear-thinning behavior. In addition, there are two main advantages of this new method. First, it can be carried out using an existing standard DSR machine typically used in most asphalt binder laboratories. Second, it can greatly improve the accuracy and efficiency of testing with sophisticated sensors and programmed settings.

To investigate the relationship between the facet fluid sign (FFS) and kinematics of affected lumbar segment in patients with low-grade, single-level lumbar degenerative spondylolisthesis using kinematic magnetic resonance imaging (kMRI).Materials and methods Ninety-two patients diagnosed with low-grade (Grade 1 or 2), single level lumbar degenerative spondylolisthesis L3 to S1. Angular and translational motion, whole lumbar motion, slip percentage, and facet angle were measured. Disc degeneration and degrees of osteoarthritis were graded, facet effusion was evaluated and classified as Positive or Negative FFS (PosFFS or NegFFS).Results There were significant differences in the facet degeneration, translational motion, percentage of total angular motion, and flexion-extension slip difference between the PosFFS and NegFFS group. 28.3% of the patients in PosFFS group had anterolisthesis in flexion, but not extension.There was a significant difference in the incidence of FFS between the dynamic and static spondylolisthesis (75% vs 35%, p 0.001). If FFS was present on kMRI, a positive predictive value for dynamic spondylolisthesis was 75.6%. with the sensitivity and specificity of 0.75 and 0.65 for posFFS to diagnose dynamic DS. The likelihood ratio for dynamic slips in the presence of FFS was 2.1, and the likelihood ratio for static slips in the presence of FFS was 1.1.Conclusion Facet fluid sign was present in weight-bearing neutral position, and the presence of FFS in kMRI increased the probability of having dynamic spondylolisthesis.

This article provides a comprehensive description of Text Analytics Directly on Compression (TADOC), which enables direct document analytics on compressed textual data. The article explains the concept of TADOC and the challenges to its effective realizations. Additionally, a series of guidelines and technical solutions that effectively address those challenges, including the adoption of a hierarchical compression method and a set of novel algorithms and data structure designs, are presented. Experiments on six data analytics tasks of various complexities show that TADOC can save 90.8% storage space and 87.9% memory usage, while halving data processing times., Comment: 25 pages, 18 figures, VLDB Journal (2020)

A compact dual-band bandpass filter (DBF) based on quarter-wavelength (λ/4) stepped impedance resonators (SIRs) with miniaturized size is presented in this Letter. The compact size of this filter is realized by using the common grounded via hole and the folded λ/4 SIRs. Common grounded via is used to adjust the coupling coefficient of the dual-band filter. The coupling path to the input/output (I/O) ports of this dual-band filter are two different space thus external quality factor of single passband can be determined independently. Two transmission zeros (TZs) is introduced between passband to realize a sharp skirt characteristics. Finally, a prototype dual-band filter centering at 4.4GHz and 7.4GHz is designed and fabricated. Simulation and measurement results are in good agreement.

In this study, the underlying causes of the performance degradation of three typical waste-oil-rejuvenated asphalts (i.e., asphalts rejuvenated by waste cooking oil (WCO), waste bio-oil (WBO), and waste engine oil (WEO)) after secondary aging are explored via SARA fractions analysis. The rejuvenation provided by WCO is found to be mainly based on supplementing aged asphalt with saturates, which causes the newly formed colloids to easily lose light components and exhibit low stability. Further, WEO contains some metal residues that catalyze the oxidation and polycondensation process of asphalt. Consequently, the performance of the asphalts rejuvenated separately by WCO and WEO is severely degraded during aging. By contrast, WBO has a stable colloidal structure and lacks ashes; thus, WBO-rejuvenated asphalt exhibits the most stable and reasonable performance degradation in the aging process. Our research suggests that the effect of rejuvenation on aged asphalt cannot be judged only by the difference between the performances of the rejuvenated asphalt and the original asphalt. The performance maintenance of the rejuvenated asphalt during the secondary aging process requires further investigation.

Periodontal ligament stem cells (PDLSCs) have been confirmed to have self-renewal capacity and multidifferentiation potential and are good candidates for periodontal tissue regeneration. Pulsed electromagnetic field (PEMF) has been demonstrated to promote osteogenesis in non-union fractures, partly by regulating mesenchymal stem cells or osteoblast activity. However, there is no report about the osteo-inductive effect of PEMF stimulation on human PDLSCs (hPDLSCs). Thus, we tested the hypothesis that PEMF biophysical stimulation alone has an influence on the proliferation and osteogenic differentiation of hPDLSCs. To detect the osteo-inductive potential of bone morphogenetic protein (BMP9), we transfected the STRO-1(+) /CD146(+) hPDLCSs with BMP9-expressing recombinant adenoviruses. We examined the proliferation and osteogenic differentiation of hPDLSCs treated with either PEMF (15 Hz, 1 h daily, different intensities), or BMP9, or both stimuli. Cell counting kit-8 (CCK-8) assay showed that PEMF of different intensities had no effect on the proliferation of hPDLSCs and did not enhance the proliferative capability of BMP9-transfected cells. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting showed that the combination of both PEMFs (1.8 or 2.4 mT) and BMP9 stimulation had a synergistic effect on early and intermediate osteogenic genes and protein expressions of runt-related transcription factor 2, alkaline phosphatase, osteopontin, and late mineralized extracellular matrix formation in hPDLSCs. Bioelectromagnetics. 38:63-77, 2017. © 2016 Wiley Periodicals, Inc.

The main inorganic minerals in natural bones are non-stoichiometric hydroxyapatite (HA, Ca10[PO4]6[OH]2) doped with various trace elements, which may possess important biochemical effects. To investigate the functions of Sr and Si elements in human hard tissues, non-doped HA, trace Si doped HA, Si and Sr codoped HA with the concentration of natural bones are synthesized by hydrothermal method in this study. The samples are characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The biological activities are evaluated via cytotoxicity study, adhesion and proliferation of osteoblast measurement, and alkaline phosphatase (ALP) assay. All the synthesized materials are HA phase, which have hierarchical structures with oriented HA nanorods assembled into the platy particles. These materials are non-cytotoxic against L929 cells line even at 400 μg/ml powder suspension. The results clearly indicate that the proliferation of L929 cells increases with trace elements doping from trace Si-HA to Si + Sr-HA. The adhesion and proliferation of osteoblast measurement illustrates that proliferation of osteoblasts advances about 1.3 times for Si-HA and about 1.8 times for Si + Sr-HA compared with undoped HA. In general, Si-HA with trace Si element shows enhanced cell differentiation, and Si + Sr-HA dual-doped with Si and Sr elements presents increased biological activity compared with Si-HA.

The biocompatibility and antibacterial properties of hydroxyapatite (HAp) bioceramics are crucial in medical applications. However, it is still a challenge to control HAp with antibacterial ability while maintaining other biological properties in the development of bioactive bone implants. Herein, we report functional silver ion substituted HAp bioceramics with excellent osteoconductivity and efficient antibacterial activity and propose a stern-interface induced antibacterial mechanism of such bioactive ceramics. In this antibacterial process, the concentration of Ag(+) at the stern-interface of Ag/HAp bioceramics is nearly 5 times higher than that in the bulk solution due to the trace dopant Ag(+) enrichment in the stern layer of the electric double layer at the negatively charged surface of Ag/HAp bioceramics. Trace Ag-doping in HAp induces a positive shift of zeta potential and increase of hydrophilicity, which may help inhibit bacterial proliferation. The positive osteoblast adhesion, proliferation and differentiation of ultra-trace doped Ag/HAp are also demonstrated through actin cytoskeleton staining, MTT and alkaline phosphatase (ALP) activity assays. This work may enlighten us on the artificial design of novel smart anti-infective bone grafts using ultra-trace functional elements and also suggest its potential applications in orthopedic surgery and bone osseointegration.

Hydroxyapatite (HAp) nanocrystals as the main inorganic component in hard tissue have been extensively studied for bone regeneration and dental implant treatment. However, failure of surgical reconstruction often occurs owing to the lack of effective antibacterial ability of HAp. It is still a challenge to develop artificial HAp with both efficient antibacterial ability and proper biological properties. Herein, a series of ultra-trace Ag-doped HAp nanocrystals have been elaborately prepared with the optimal doping concentration from 0.27 ppm to 2.2 ppm, which present non-cytotoxicity while possess effective bacteria reduction ability. Ultra-trace Ag-doped HAp nanocrystals possess higher protein adsorption than pure HAp nanocrystals due to the trace doping-induced less negative surface potential. The ultra-trace Ag-doped HAp nanocrystals showed effectively antibacterial ability, non-cytotoxicity and enhanced adsorbability that made them ideal materials for various biocompatible and antibacterial applications.

Purpose: The decoction of collagen extracted from Carapacis et Plastri Testudinis (CCPT) has been reported to have an effect of anti-osteoporosis. The present study was to investigate the in vitro molecular mechanisms effect of CCPT on ROS1728 differentiation and proliferation. Methods: Rat osteoblast cell line (ROS 1728) was cultured and exposed to CCPT at different concentrations. The effect of CCPT on the proliferation of ROS1728 was evaluated through detecting the activity of Alkaline Phosphatase (ALP) and the type I collagen (Coll-I) content. The gene expression of ALP, Coll-I, Osteocalcin (OC), Runx2, Osterix (Osx), Osteoprotegerin (OPG) and RANKL (receptor activator of NF-MB ligand) was observed using RT-PCR analysis. Results: The results showed that CCPT treatment (2.5, 5.0 and 10.0 mg/ml) affected the proliferation of ROS1728 in a concentration-dependent manner. The highest expression was obtained by treatment with 5 mg/ml of CCPT after a nine-day treatment duration based on ALP activity and Coll-I content (P

Semi-flexible composite mixture (SFCM) is developed based on a unique material design concept of pouring cement mortar into the voids formed by open graded asphalt mixture. It combines the flexibility of asphalt concrete and the stiffness of Portland cement concrete and has many advantages comparing to conventional roadway paving materials. The main objective of this paper was to evaluate the engineering properties of SFCM and assess the constructability of the SFCM. A slab SFCM sample was fabricated in the laboratory to simulate the filling of cement mortar in the field. Performance testing was carried out by indirect tensile (IDT) test because it was found to be able to correlate with the field performance of asphalt mixtures at low, intermediate, and high temperatures. They were used in this study to evaluate the thermal cracking, fatigue, rutting, as well as moisture resistance of SFCM. A control hot mix asphalt (HMA) mixture was used to compare with the results of SFCM. Based on the testing results, it was found that the designed SFCM showed good filling capability of cement mortar. SFCM had higher dynamic modulus than the control HMA. It had good resistance to rutting and moisture damage. Based on fracture work, SFCM showed better resistance to thermal cracking while lower resistance to fatigue cracking.

The oriented hierarchical architecture of hydroxyapatite (HA) shows excellent performance in multiple functions in human hard tissues such as bone and teeth. It is a challenge to mimic the architecture of biomineralization products. This study introduces a simple method for the hierarchical architecture of pure stoichiometric HA by a one-pot hydrothermal process without adding any organic molecules. The reaction process is researched by XRD, FT-IR, SEM, and TEM, and the HA crystal growth mechanism is discussed. The short rod-like HA nanocrystals are orderly assembled into micrometer-sized platy particles with the DCPD (CaHPO4·2H2O, brushite) shape retained. The ordered HA hierarchical architectures are achieved through topotactic transformation due to the crystal structural similarity from DCPD through DCPA (CaHPO4, monetite) to HA. It is found for the first time that the growth of HA crystals on DCPA is accompanied by orientation relationship of HA [110] // DCPA [110] and HA (112) // DCPA (112). The re...

Previous studies have shown that neurofilament protein M expression is upregulated in the early stage of spinal cord ischemia/reperfusion injury, indicating that this protein may play a role in the injury process. In the present study, we compared protein expression in spinal cord tissue of rabbits after 25 minutes of ischemia followed by 0, 12, 24, or 48 hours of reperfusion with that of sham operated rabbits, using proteomic two-dimensional gel electrophoresis and mass spectrometry. In addition, the nerve repair-related neurofilament protein M with the unregulated expression was detected with immunohistochemistry and western blot analysis. Two-dimensional gel electrophoresis and mass spectrometry showed that, compared with the sham group, upregulation of protein expression was most significant in the spinal cords of rabbits that had undergone ischemia and 24 hours of reperfusion. Immunohistochemical analysis revealed that neurofilament protein M was located in the membrane and cytoplasm of neuronal soma and axons at each time point after injury. Western blot analysis showed that neurofilament protein M expression increased with reperfusion time until it peaked at 24 hours and returned to baseline level after 48 hours. Furthermore, neurofilament protein M is phosphorylated under oxidative stress, and expression changes were parallel for the phosphorylated and non-phosphorylated forms. Neurofilament protein M plays an important role in spinal cord ischemia/reperfusion injury, and its functions are achieved through oxidative phosphorylation.

To investigate the changes of lumbar neural foramina size during dynamic motion using positional MRI. Two hundred and fifty neural foramina from 50 patients were analyzed. Lumbar foraminal height, width, and area parameters from L1 to S1 were evaluated for changes in extension, neutral, and flexion positions on T2 parasagittal positional MRI images, and were correlated to lumbar angular motion. One-way analysis of variance (ANOVA) and post hoc analysis were used to examine the differences between levels and positions. Compared to the neutral position, almost all lumbar foraminal parameters (height, width at inferior level, and area) increased in flexion and decreased in extension at all levels, except for L5–S1 foraminal width at superior and middle levels. The foraminal height and area in all lumbar segments except L5–S1 increased as the lumbar angular motion changed from extension to flexion in

Periodontal ligament stem cells (PDLSCs) have been confirmed to have self-renewal capacity and multidifferentiation potential and are good candidates for periodontal tissue regeneration. Pulsed electromagnetic field (PEMF) has been demonstrated to promote osteogenesis in non-union fractures, partly by regulating mesenchymal stem cells or osteoblast activity. However, there is no report about the osteo-inductive effect of PEMF stimulation on human PDLSCs (hPDLSCs). Thus, we tested the hypothesis that PEMF biophysical stimulation alone has an influence on the proliferation and osteogenic differentiation of hPDLSCs. To detect the osteo-inductive potential of bone morphogenetic protein (BMP9), we transfected the STRO-1

Carbon microspheres were synthesized through polymerization of urea/formaldehyde in the presence of formic acid as catalyst, followed by drying and carbonization in an inert atmosphere. The samples were characterized by SEM, XRD, HRTEM, elemental analysis and XPS. The obtained carbon microspheres were amorphous indicated by the results of XRD and HRTEM. The changes of nitrogen functionalities at 400–1000 °C were determined by XPS. The fraction of pyridine nitrogen and pyrrole/pyridone nitrogen decreased with increasing temperature, whereas the amount of quaternary nitrogen increased.

Zirconia is a kind of prospective hard tissue implant materials, which possesses superior mechanical properties and excellent biocompatibilities. To promote the stable osseointegration between Zirconia implants and tissue, zirconia-toughened trace Sr-, Si- and F- co-doped hydroxyapatite (ZrO2-DHA) was coated by plasma spraying on zirconia. The phase composition and structure of coatings were characterized, and the mechanical properties and in vitro biological properties were investigated. The results show that co-doping of trace Sr, Si and F enhances the biological properties of coatings on adhesion and differentiation of osteoblasts through the signal transduction pathway of osteogenic differentiation. All of ZrO2-DHA coatings promote the cell viability and gene expression in osteogenic differentiation of MC3T3-E1. On the 7th day of cell culture, the relative expression levels of Alp and Col-I in the ZrO2-DHA coating containing 70% DHA (7DHA) were about 2.8 times and 2.3 times higher than those in the ZrO2 substrate group, respectively. Mechanical properties of ZrO2-DHA coatings are improved with the increment of zirconia ratio. Hardness of DHA coating and 7DHA coating are 250.8 and 313.8HV respectively and their bond strength are 25.1 and 31.8 MPa, respectively. 7DHA coatings with network structure possess both excellent mechanical and biological performance for the implant coating application.

A metallic Ni catalyst was prepared with nickel sponge, followed by acid treatment. It was further promoted with yttria by an impregnation method. The catalysts were characterized by SEM, BET, XRD, TPR, XPS, etc ., and studied in the partial oxidation of methane to syngas. The characterization results showed that the yttria promoted metallic Ni catalysts had high specific surface area and more NiO. The reaction results showed that the yttria promoter increased the CH 4 conversion and the selectivity for H 2 and CO.

The objective of this study is to examine the influence of bus stop location on bus priority efficiency for arterials with segmented signal progression control. A simulation approach is used to explore the effects for an arterial with five intersections and three bus-bay stops. Analyses are conducted to investigate the relationship between traffic volume and delay (bus or car delay) for given bus stop locations (far-side, near-side, and midblock). The results suggest that a far-side bus stop is generally a better choice than a near-side one, especially when intersection spacing is tight. When intersection spacing increased to 300 or 450 meters, bus stop locations have a smaller effect on the efficiency of bus priority, and results showed that a far-side stop location is still a better choice.

The aim of this study was to investigate the prevalence and characteristics of imipenem-resistant Acinetobacter baumanni isolated from surgical wards in a university hospital, China. A total of 143 non-duplicate A. baumannii were isolated from 517 inpatients in surgery intensive care units (ICUs), burn wards, and general surgery wards. Of these, 102 isolates of A. baumannii (71.3%) were resistant to imipenem. Among imipenem-resistant isolates, all isolates were resistant to almost all antimicrobial agents except polymyxin E, all isolates were positive for blaOXA-23 and blaOXA-51 in addition to ISAba1, 52 (51%) were positive for blaOXA-58, 8 (7.8%) contained blaVIM-2, which co-harbored with blaOXA-58. Molecular typing revealed the presence of three clones among imipenem-resistant isolates. This study confirmed that A. baumannii strains harboring OXA or VIM type β-lactamases are widely distributed throughout the surgery wards. The data demonstrate that there was a high prevalence of imipenem-resistant A. baumannii infection in the region.

To study the effect of implant number and inclination on stress distribution in implant and its surrounding bone with three-dimensional finite element analysis.A special denture was made for an edentulous mandible cast to collect three-dimensional finite element data. Three three-dimensional finite element models were established as follows. Model 1: 6 paralleled implants; model 2: 4 paralleled implants; model 3: 4 implants, the two anterior implants were parallel, the two distal implants were tilted 30° distally.Among the three models, the maximum stress values found in anterior implants, posterior implants, and peri-implant bone were modle 3modle 1modle 2 in turn. The effect of implant numbers on stress distribution was as follow: the maximum stress value of the anterior and posterior implant, and the peri-implant bone of model 2 were 126.8, 267.4, and 40.0 MPa, which was 35.8%, 3.8% and 7.8% higher than those in model 1 (93.4, 257.7, 37.1 MPa) respectively. The impact of implant inclination on stress distribution was as follow: when the distal implant titled 30° in model 3, the maximum stress value of the anterior and posterior implant, and the peri-implant bone were 82.0, 239.5 and 28.7 MPa, which was 35.4%, 10.5% and 28.2% lower than those in model 2 respectively.Within the limitation of this study, when implants are placed parallel, the maximum stress of the distal implant can be reduced by increasing the number of implant.When the number of implant was decreased from six to four, the maximum stress around the implant can be reduced by tilting the distal implant. This design will provide a better prostheses effect than the design with six implants does.

Background There is growing evidence that periodontal treatment may affect glycemic control in diabetic patients. And several systematic reviews have been conducted to assess the effect of periodontal treatment on diabetes outcomes. Researches of this aspect are widely concerned, and several new controlled trials have been published. The aim of this study was to update the account for recent findings. Methods A literature search (until the end of January 2014) was carried out using various databases with language restriction to English. A randomized controlled trial (RCT) was selected if it investigated periodontal therapy for diabetic subjects compared with a control group received no periodontal treatment for at least 3 months of the follow-up period. The primary outcome was hemoglobin A1c (HbA1c), and secondary outcomes were periodontal parameters included probing pocket depth (PPD) and clinical attachment level (CAL). Results Ten trials of 1135 patients were included in the analysis. After the follow-up of 3 months, treatment substantially lowered HbA1c compared with no treatment after periodontal therapy (–0.36%, 95%CI, −0.52% to −0.19%, P

Medical education models play an important role in medical education, especially in military medical education. However, there are shortcomings in various existing teaching models of maxillofacial gunshot injuries. To resolve this issue, we integrated a dynamic simulation of image data to create a new, three-dimensional dynamic digital teaching model that was based on our previous completed three-dimensional finite element model of human maxillofacial bone tissue gunshot injuries. This model was applied to teaching practice with good results. The new model has helped us to achieve the teaching objective and improve the teaching efficiency.

Free radial forearm flaps have many advantages and thus remain the dominant multi-purpose flap used in the reconstruction of maxillofacial soft tissue defects. This report summarizes our experience over 20 years of applying free radial forearm flaps and illustrates four stages of technical improvement regarding the selection of the anastomotic veins at the donor site and at the recipient site in addition to the choice of the method to be used for flap harvest. We believe that the key to improving the transplantation success rate for free radial forearm flaps is based on the following factors. First, the branches of the internal jugular vein are the preferred targets for anastomosis at the recipient site. Second, during flap harvest, it is necessary to retain the external fascia between the arteries and veins. Third, it is necessary to select veins in two vascular systems of different depths for concurrent anastomosis.

PURPOSE To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle (0°, 30° and 45°) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.

All-optical single-to-dual channel format con-verter from non-return-to-zero NRZ to return-to-zero RZis proposed and demonstrated using cascaded sum- anddifference-frequency generation SFG+DFG in a periodi-cally poled LiNbO 3 PPLN waveguide. The pump opticalclock is generated from the active mode locking in a reflec-tive semiconductor optical amplifier RSOA -based fiber ringlaser. We successfully observe 10- and 20-Gbit/s single-to-dual channel NRZ-to-RZ format conversions in theexperiment. © 2007 Society of Photo-Optical Instrumentation Engineers. DOI: 10.1117/1.2823496 Subject terms: nonlinear optics; all-optical format conversion;non-return-to-zero; return-to-zero; cascaded sum- and difference-frequency generation; periodically poled LiNbO 3 . Paper 070495LR received Jun. 14, 2007; revised manuscriptreceived Sep. 6, 2007; accepted for publication Sep. 6, 2007;published online Dec. 21, 2007. 1 Introduction An all-optical format converter is an essential element inall-optical signal processing for future high-speed telecom-munication. The basic format conversion from non-return-to-zero NRZ to return-to-zero RZ is very important andhas been successfully implemented using devices based ona nonlinear optical loop mirror

We report the experimental demonstration of all-optical format conversion by exploiting the cascaded second-harmonic generation and difference-frequency generation (cSHG/DFG) in a periodically poled lithium niobate (PPLN) waveguide assisted by the reflective semiconductor optical amplifier (RSOA)-based active mode-locking. 10 and 20 Gbit/s format conversions from non-return-to-zero (NRZ) to return-to-zero (RZ) are successfully observed. Two schemes with either the NRZ signal or the pump optical clock set at the quasi-phase matching (QPM) wavelength are both verified in the experiment.

In the present letter, the authors report on the realization of all-optical format conversion by using the cascaded sum- and difference-frequency generation in a periodically poled lithium niobate waveguide and the active mode locking in a reflective-semiconductor-optical-amplifier-based fiber ring laser. Tunable format conversions from nonreturn-to-zero pseudorandom binary sequence (PRBS) signal to return-to-zero PRBS idler at 10 and 20Gbit∕s are observed in the experiment.

All-optical 40 Gbit/s format conversion from nonreturn-to-zero (NRZ) to return-to-zero (RZ) is proposed and simulated for the first time, using the cascaded sum- and difference-frequency generation (SFG+DFG) in a periodically poled lithium niobate (PPLN) waveguide incorporated in a Sagnac interferometer structure. Simultaneous single-to-triple channel NRZ-to-RZ format conversion is achieved. Both optical spectra and eye diagrams exhibit impressive conversion performance. The duty cycle, pulse width ratio, Q-factor and extinction ratio (ER) of the converted RZ are analyzed. It is found that flexible NRZ-to-RZ format conversion can be implemented with great tunability, i.e. both input NRZ signal wavelength and converted RZ wavelength can be tuned in a wide wavelength range (>60 nm).