Active video games in fully immersive virtual reality elicit moderate-to-vigorous physical activity and improve cognitive performance in sedentary college students

BACKGROUND

Active video games are a new method for increasing physical activity (PA). Fully immersive virtual reality (VR) is a hardware device on which an active video game can run. Active (video games in) VR (AVR), might increase immersion, game engagement, and moderate-to-vigorous PA (MVPA), thereby yielding greater exercise-related benefits, e.g., cognitive performance.

METHODS

We examined the induction of MVPA via an AVR and a sedentary VR (SVR) as well as the effects of VR play on cognitive performance, which was monitored using 2 different methods. Each of 29 sedentary college students attended three 20-min laboratory sessions (AVR, SVR, or control) in a randomized order; during the control session, they sat quietly doing nothing. A fully immersive headset was used for the 2 video game sessions. We monitored and computed participants' PA using hip-worn accelerometers (wGT3x-bt; ActiGraph, Pensacola, FL, USA) and a heart rate band (Polar H7; Polar, Kempele, Finland). After each session, the participants completed a mnemonic similarity test (MST) to measure recognition memory. They also filled out a motion sickness questionnaire and an abbreviated game experience questionnaire.

RESULTS

The AVR session induced a significantly greater heart rate and more time spent in MVPA than did either of the other 2 sessions regardless of the PA monitoring method. AVR elicited greater game experience questionnaire-assessed sensory and imaginative immersion, challenge, and positive affect than did SVR. The mnemonic similarity test recognition score was marginally higher post-AVR session than it was post-SVR session.

CONCLUSION

AVR elicited MVPA without a significant increase in motion sickness and induced a better game experience and better borderline cognitive performance than did SVR.

The impact of narratives and active video games on long-term moderate-to-vigorous physical activity: A randomized controlled trial protocol

BACKGROUND

Although physical activity (PA) has been shown in helping prevent and treat obesity, current PA interventions are still not effective in ameliorating the obesity epidemic. Additional forms of PA need to be investigated to improve PA engagement and outcomes. We hypothesize that pairing a narrative (i.e., story) with an active video game (AVG), a less traditional form of PA, will increase participant engagement in PA. This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes.

OBJECTIVE

This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes.

METHODS/DESIGN

The Active Video Game Study is a six-month randomized controlled single-blind trial projected to include 210 participants. The intervention strategy will pair a narrative to an active video game (AVG). Participants will be randomized into 3 groups: condition A [Narrative + AVG], condition B [AVG Only], and condition C [Control]. Participants will undergo three in-person data collection visits over the course of six months. Inclusion criteria are that children are between the ages of 8-12 and have a BMI ≥ 85%. The primary outcome is change in moderate to vigorous physical activity (MVPA). Secondary outcome measures include change in BMI percentile, fasting insulin and glucose, lipid panel, C-reactive protein, and cognitive function. A pilot trial of n = 6 was conducted to help develop procedures and address problems that could arise in the main trial.

DISCUSSION

Successful completion of this study will provide the empirical basis for novel intervention and design strategies to enhance the impact of AVGs on long-term MVPA.

Erythrina Cristagalli Lectin-reactive α-fetoprotein-E2: A Marker of Hepatocellular Carcinoma and Other Malignancies

A newly isolated lectin Erythrina cristagalli (ECL) was tested for separation of human α-fetoprotein (AFP) glycoforms by affinity electrophoresis at 0.5 mg/ml and separated AFP bands were detected by antibody-affinity blotting. Three AFP bands, AFP-E1, AFP-E2 and AFP-E3 in order of increasing affinity, were obtained. Sera from control patients with chronic hepatitis and cirrhosis gave a major band of AFP-E1 and a minor or trace band of AFP-E2 (3.4±2.3%), while those from patients with mostly advanced hepatocellular carcinomas had increased proportions of AFP-E2 band (16.6±10.2%). With a cutoff level of 8% (mean+2SD of AFP-E2 for controls), the sensitivity for hepatocellular carcinoma was 72% at a specificity of 100%. Gastrointestinal tumors had much higher percentages of AFP-E2 and occasionally positive AFP-E3. Most of the yolk sac tumors examined showed AFP-E3 in addition to AFP-E2, although AFP-E3 was a minor band. Thus, AFP-E2 is potentially a clinically useful marker for differentiation of increased AFP in hepatocellular carcinoma and other malignancies from that in precancerous chronic hepatitis or cirrhosis.

RASSF1A hypermethylation in pretreatment serum DNA of neuroblastoma patients: a prognostic marker

The tumour suppressor gene RASSF1A is known to be frequently silenced by promoter hypermethylation in neuroblastoma tumours. Here we explored the possible prognostic significance of aberrant promoter hypermethylation of RASSF1A in serum DNA samples of patients with neuroblastoma as a surrogate marker for circulating tumour cells. We analysed the methylation status of the RASSF1A gene in matched tumour and pretreatment serum DNA obtained from 68 neuroblastoma patients. Hypermethylation of RASSF1A in tumour samples was found in 64 patients (94%). In contrast, serum methylation of RASSF1A was observed in 17 patients (25%). Serum methylation of RASSF1A was found to be statistically associated with age ⩾12 months at diagnosis (P=0.002), stage 4 (P<0.001) and MYCN amplification (P<0.001). The influence of serum RASSF1A methylation on prognosis was found to be comparable with that of the currently most reliable marker, MYCN amplification on univariate analysis (hazard ratio, 9.2; 95% confidence interval (CI), 2.8–30.1; P<0.001). In multivariate analysis of survival, methylation of RASSF1A in serum had a hazard ratio of 2.4 (95% CI, 0.6–9.2), although this association did not reach statistical significance (P=0.194). These findings show that the methylation status of RASSF1A in the serum of patients with neuroblastoma has the potential to become a prognostic predictor of outcome.

Continuous remission in an infant with chest wall malignant rhabdoid tumor after relapse

Malignant rhabdoid tumor (MRT) is a highly aggressive tumor that occurs in infancy or childhood. The prognosis, especially in infants, is very poor. Here we report the long-term survival of a 5-month-old boy with MRT that arose from the chest wall. After total resection of the tumor, the patient was given 4 cycles of doxorubicin, vincristine, and cyclophosphamide, alternating with ifosfamide and etoposide. After 18 months off therapy, he had a local recurrence at the same site. After a second total resection, he was given additional chemotherapy with 30.6-Gy local irradiation. No further recurrence has been observed for 5 years since the second complete remission. Currently, he is alive and well at 7.5 years post-onset. Our experience in this case suggests a fundamental strategy of successful treatment of this highly malignant pediatric tumor: (1) complete resection of the localized tumor, (2) intensive multiagent chemotherapy for the minimal disseminated disease, and (3) radiotherapy for local control of the disease.

Development of a novel information technology (IT) system using the electronic medical record (EMR) in daily clinical practice

17066

Background: The information generated in daily practices is critical to assure safety and efficacy of therapeutic interventions. Clinical investigators are faced with enormous amounts of data and a greater need to organize it in a meaningful and coherent manner than ever before. Computerization could offer many advantages that clinical data systematically accumulated in the course of routine medical care can provide researchers with the clues to resolve many medical questions. Methods: We developed a novel clinical database system, named CyberOncology, integrated in EMR of Kyoto University Hospital. It contained summarized treatment history, national cancer registry and consecutive clinical database. All adverse events according CTCAE ver.3, response to the treatment based on RECIST criteria and survival data were collected. The medical staffs have routinely used the CyberOncology since its starting on October 2003. The CyberOncology directly collected all data concerning oncology management of inpatient and outpatient care from EMR, and simultaneously analyzed clinical outcomes. Results: For three years since October 2003, consecutive 1,516 new cancer patients including 590 GI, 435 lung, 234 breast cancer, and 140 lymphoma with 19,767 chemotherapeutic administrations were registered in the CyberOncology. Main benefits are improvement of the quality of patient care and safety, practice standardization, and the quickness and the reliability of collecting the data. Moreover, it had the capability to serve a cross-sectional approach of cancer and drug-orientated analysis. For example, this system can easily provided with a review of clinical practice in a real time manner. Conclusions: The CyberOncology form integrated EMR successfully meets requirements of electronic case report. It has been useful in monitoring outcomes of care, effectiveness, efficiency and adherence to clinical trial.

No significant financial relationships to disclose.

Epigenetic silencing of prostaglandin E receptor 2 (PTGER2) is associated with progression of neuroblastomas

We previously identified a cluster of prostanoid receptor genes, prostaglandin D2 receptor (PTGDR) and prostaglandin E receptor 2 (PTGER2), as possible targets for DNA methylation in advanced types of neuroblastoma (NB) using bacterial artificial chromosome array-based methylated CpG island amplification method. Among them, in this study, we found that PTGER2 was frequently silenced in NB cell lines, especially in those with MYCN amplification, through epigenetic mechanisms. In NB cell lines, DNA methylation pattern within a part of CpG island was inversely correlated with PTGER2 expression, and histone H3 and H4 deacetylation and histone H3 lysine 9 methylation within the putative promoter region were more directly correlated with silencing of this gene. Methylation of PTGER2 was observed more frequently in advanced-type of primary NBs compared with early-stage tumors. Growth of NB cells lacking endogenous PTGER2 expression was inhibited by restoration of the gene product by transient and stable transfection. A PTGER2-selective agonist, butaprost, increased intracellular cyclic adenosine monophosphate (cAMP) level, inhibited cell growth and induced apoptosis of NB cells stably expressing exogenous PTGER2. 8-Bromo-cAMP also inhibited growth of NB cells lacking PTGER2 expression, but not cells expressing this gene. Taken together, it is suggested that NB cells may lose responsiveness to PTGER2-mediated growth inhibition/apoptosis through epigenetic silencing of PTGER2 and/or disruption of downstream cAMP-dependent pathway during the neuroblastomagenesis.

Sex differences in the hemoglobin oxygenation state of the resting healthy human masseter muscle

AIMS

To determine whether sex differences exist in tissue oxygen saturation (StO2) and the hemoglobin (Hb) oxygenation state of the resting human masseter muscle.

METHODS

Near-infrared spectroscopy (NIRS) was used to measure StO2 and Hb oxygenation state in 20 healthy adult volunteers (10 women and 10 men). To determine the measurement range and reliability of the NIRS recording probe, the probe was set up on 12 layers of white acrylic resin plate, each 3 mm thick. Total hemoglobin levels were measured while a red vinyl resin plate, 1 mm thick, was inserted in turn between each of the 12 layers. Distances from the skin surface to the lateral surface (S-L) and to the medial surface (S-M) of the right masseter at the middle portion of the masseter were measured on T1-weighted magnetic resonance images (repetition time 500 ms, echo time 23 ms). Thickness of the masseter was calculated by subtraction [(S-M)--(S-L)]. For the study of Hb oxygenation state, the probe was positioned at the same position on the skin surface at the mandibular postural (rest) position.

RESULTS

The measurement range of the NIRS probe was from 9 to 21 mm under the skin, and the reliability of the probe was judged by intra- and inter-class correlation coefficients. There was no sex difference in S-L and the thickness of the masseter; the means of S-L and masseter thickness were 9.3 mm and 15.5 mm in men and 9.8 mm and 14.3 mm in women, respectively. Except for StO2 values, there were significant sex differences in the Hb oxygenation parameters, with the mean values in the men being approximately twice those in the women.

CONCLUSION

These results provide evidence that a sex difference in the Hb oxygenation state may exist in the masseter muscle of normal healthy subjects.

The effects of therapeutic electric stimulation on acute muscle atrophy in rats after spinal cord injury

OBJECTIVE

To evaluate the effects of electric stimulation in preventing acute muscle atrophy after spinal cord transection in rats.

DESIGN

A randomized experimental design.

SETTING

Animal facilities for experimental medicine.

ANIMALS

Fifty-six adult male Wistar rats assigned to control, low-frequency, and high-frequency groups.

INTERVENTIONS

The rats were implanted with a percutaneous intramuscular electrode in the vicinity of the peroneal nerve; then the spinal cord was transected in a T9 level. The stimulation frequency was low (20Hz) or high (100Hz). The stimulation cycle was 4 seconds of stimulation every 8 seconds.

MAIN OUTCOME MEASUREMENTS

The lesser fiber diameters from type 1, 2A, and 2B muscle fibers were measured. In another assessment, maximal contraction force was measured. The muscle force produced at 20 and 100Hz was expressed as increasing values in tetanic force.

RESULTS

Comparison between nonstimulated and stimulated tibialis anterior muscles found that atrophy of type 1 fibers (p < .01) and type 2B fibers (p < .05) at both stimulated levels and of type 2A fibers at 100-Hz level (p < .05) was prevented by therapeutic electric stimulation (TES). There were significant differences in the size of muscle fiber diameter between nonstimulated and stimulated muscles at 100Hz in type 2A and, markedly, in type 2B. The increasing value of muscle force was significantly greater at 100Hz than at 20Hz (p < .05). No significant histologic differences were observed between high- and low-frequency stimulated fibers of any of the 3 muscle types.

CONCLUSIONS

Acute atrophy of muscle fibers was more effectively prevented by high-frequency stimulation (100Hz) than by no stimulation or low-frequency stimulation (20Hz). The increasing value of muscle force was significantly greater at high-frequency than low-frequency stimulation, suggesting that the clinical application of high-frequency stimulation in acute spinal cord injury should be studied.

Closed-loop control using a stretch sensor for restoration of standing with functional electrical stimulation in complete paraplegia

A closed-loop control system for standing with functional electrical stimulation (FES) using percutaneous intramuscular electrodes in complete paraplegia is described. The system consisted of ultrafine percutaneous intramuscular electrodes, a 32-channel stimulator and a stretch sensor with active current control to detect knee buckling. The closed-loop control system was applied in a T8 completely paraplegic patient. Compared to the stretch sensor with a wide use flexible goniometer for direct current control during standing, the stretch sensor was superior to the flexible goniometer in both ease of use and response. The average time delay from the start of knee buckling until the sensor turned on was 0.56+/-0.19 seconds (Mean+/-S.D.) in the goniometer and 0.21+/-0.06 seconds in the stretch sensor. The average time delay from the start of knee buckling until the recovery from knee buckling was 1.01+/-0.05 seconds in the goniometer and 0.78+/-0.06 seconds in the stretch sensor. The continuous standing ability of the patient increased from 12 minutes with open-loop stimulation to 30 minutes with the closed-loop control. No complications such as falling occurred during clinical use. This system prevented falling due to knee buckling during standing and prolonged upright activities in complete paraplegics.

Putaminal necrosis presenting with hemidystonia

A 7-year-old female presented with putaminal necrosis associated with hemidystonia. Cranial magnetic resonance imaging revealed bilateral putaminal lesions appearing as hypointense signals on T(1)-weighted images and hyperintense signals on T(2)-weighted images. After a differential diagnosis of basal ganglial degeneration was made, putaminal necrosis was diagnosed. Low doses of levodopa (0.5 mg/kg daily) were administered, but her clinical signs worsened. Positron emission tomography scanning with [(18)F]-6-fluoro-L-dopa revealed asymmetric uptake and right-sided dominant decreases of [(18)F]-6-fluoro-L-dopa uptake of the putamen. On the basis of these findings, standard doses of levodopa (10 mg/kg daily) were administered, and her clinical signs improved. These results suggest that hemidystonia is associated with a disturbance of the dopamine system.

FK506-induced intractable leukoencephalopathy following allogeneic bone marrow transplantation

FK506-related leukoencephalopathy has been reported to be reversible and readily treated by discontinuation or reduction of FK506. We describe two pediatric cases of FK506-related leukoencephalopathy following allogeneic bone marrow transplantation, which could not be readily controlled. These cases show that FK506-related leukoencephalopathy is not always reversible, and patients may develop epilepsy. Bone Marrow Transplantation (2000) 25, 331-334.

Dumb-bell-type teratoma in the lumbar spine

We report a case of a lumbar teratoma in a 50-year-old woman. The teratoma showed a dumb-bell-type expansion at the level of the left L3/4 foramen with massive erosion of the L3 vertebral body. MRI revealed inhomogeneous signal changes in the tumor, which were histologically compatible with a mixture of bone, muscle, fat, and cyst containing sebaceous material. Complete resection of the tumor and spinal arthrodesis with pedicle screw fixation was necessary to obtain stability of the affected spinal segment.

N-Myc induction stimulated by insulin-like growth factor I through mitogen-activated protein kinase signaling pathway in human neuroblastoma cells

Insulin-like growth factor I (IGF-I) stimulates proliferation, survival, and differentiation in many cell types, including pediatric neuroblastomas. The effect is mediated via the type I IGF-I receptor (IGF-IR), which is essential for growth in these cells. Several lines of evidence indicate that IGF-IR function may be particularly important in the pathogenesis of neuroblastoma. Amplification of the N-myc oncogene or overexpression of N-Myc oncoprotein has been reported to be associated with resistance to therapy and poor prognosis of neuroblastomas. It was therefore of interest to analyze whether IGF-I signaling regulated expression of N-myc in KP-N-RT human neuroblastoma cells as an experimental model that has amplified N-myc. We found that IGF-I induces N-myc mRNA and protein in the KP-N-RT with maximums of four and six times more than the basal level at 2 and 3 h after stimulation, respectively. These effects of IGF-I were blocked by a neutralizing antibody against IGF-IR (alpha-IR3). Exogenous IGF-I induced phosphorylation and activation of extracellular signal-regulated kinases p44/42 (ERK1 and ERK2), with a maximal level 30 min after the stimulation. The MEK1 inhibitor PD98059 reduced IGF-I-mediated p44/42 MAPKs phosphorylation and produced a parallel reduction of IGF-I-stimulated N-Myc induction. Furthermore, both alpha-IR3 and PD98059 inhibited G1-S cell cycle progression stimulated by IGF-I. Our results demonstrate that IGF-I induces N-Myc in the KP-N-RT neuroblastoma cell line at the RNA level and establishes a clear correlation between N-Myc induction and activation of p44/42 MAPK signaling.

Fibroma of tendon sheath arising from the radio-ulnar joint

A report of a 65-year-old male with a tumor arising from synovial tissue of the radio-ulnar joint. On magnetic resonance imaging, the tumor was demonstrated as a heterogeneous and lobulated mass with a low signal intensity both in T1- and T2-weighted images. Histological findings of the tumor were identical to those of fibroma of the tendon sheath. In the peripheral villous synovial tissue, several small and fibrous nodules were observed, and their histological features were identical to those of the main tumor. Immunohistochemically, the tumor cells showed diffuse and intense reactivity to vimentin, muscle actin and S-100. These results indicated that the tumor might be a fibromatous analog of synovial chondromatosis.

[Post-transplant EBV-associated lymphoproliferative disorders--report of two cases]

We report two cases of Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPD) after allogenic bone marrow transplantation which were conditioned with regimens including antithymocyte globulin (ATG). The first case was a 31 year-old man which severe aplastic anemia who was transplanted from HLA-matched unrelated donor conditioned with total lymphoid irradiation (TLI)/ cyclophosphamide/ATG and prophylactic administration of ganciclovir Grade I acute GVHD improved in response to cyclosporine (CsA). LPD as a polyclonal epipharyngeal mass developed at day +53 and spontaneously regressed along with the withdrawal of CsA. Second case was a 11 year-old boy with acute myelomonocytic leukemia (FAB:M4E). He was transplanted from HLA B locus mismatched mother conditioned with total body irradiation (TBI)/busulfan/L-PAM/ATG. He showed grade IV acute GVHD, which was controlled by steroids and FK-506. LPD as a monoclonal intestinal lymphoma was diagnosed at day +82, and he was unsuccessfully treated with ganciclovir, acyclovir, chemotherapy and transfusions of EBV-specific cytotoxic lymphocytes in addition to discontinuation of immunosuppressants, and died at day +18 due to sepsis and multiple cerebral infarction. Early detection and introduction of appropriate treatment for post bone marrow transplantation LPD is necessary.

Multiple pulmonary nodules after recovery from chickenpox in a patient with chronic lymphocytic leukaemia

A 61-year-old woman with chronic lymphocytic leukaemia (CLL) was found to have multiple pulmonary nodules on an annual chest radiograph 4 months after recovery from chickenpox. To exclude the metastatic carcinoma, an open lung biopsy was performed. Histological examination disclosed isolated necrotic nodules surrounded by some lymphocytes and a few giant cells. These histological findings were compatible with healed varicella pneumonia and the DNA of varicella-zoster virus (VZV) was detected by polymerase chain reaction (PCR) method. We report a case of asymptomatic pulmonary involvement of VZV infection in a patient with CLL.

Asymptomatic pulmonary hypertension complicated with antiphospholipid syndrome case

A 48-year-old woman with antiphospholipid syndrome (APS) developed pulmonary hypertension without any thromboembolic episode. Multiple pulmonary perfusion defects suggestive of pulmonary thrombosis or in situ thrombosis were observed. Deep venous thrombosis (DVT) of the right femoral vein without symptoms was also detected by contrast venography. Asymptomatic pulmonary hypertension complicated with a hypercoagulable state such as in this case suggests that not only recurrent asymptomatic pulmonary thrombosis, but also in situ thrombosis in pulmonary vessels are possible and important factors in the pathogenesis of pulmonary hypertension.

[Clinical usefulness of urinary anti HIV antibody test--a large scale study from 11 institutes in Japan]

An enzyme immuno assay kit has been developed to detect anti-HIV antibody in urine. In order to examine the clinical utility of the kit, 1333 urine samples were assayed. These samples consisted of 233 urine samples from HIV infected patients, 472 samples from HIV uninfected patients including 203 samples from patients with urogenital diseases, and 628 samples from normal subjects. Anti-HIV antibodies were detected in all the urine samples from HIV infected patients, and the diagnostic sensitivity for HIV infection was 100% with no false negative cases. A variety of anti-HIV antibody titers were found in the urine samples from HIV infected patients. However, no significant differences were found in the distribution patterns of urinary anti-HIV antibody titers among AC, ARC and AIDS patients. False positives were determined in only five samples in 628 healthy subjects (0.8%), one in 19 patients with hepatitis (5.3%), one in 45 patients with hemophilia (2.2%) and two in 105 pregnant women (1.9%). The antibody titers of all the false positive samples in these groups were less than the cut-off index multiplied by two. However, relatively high positive rates were demonstrated in the samples from urogenital diseases (11.8%), diabetes mellitus (20.0%) and auto-immune diseases (7.3%). False positive results were found to be directly correlated to the protein concentration of urinary protein, especially the immunoglobulin concentration in urine. The assay system was also evaluated by various reproducibility tests performed by different operators at different laboratories. The test results were satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

[Autosomal dominant spinocerebellar degeneration with pigmentary retinopathy in a Japanese family]

We report a pedigree of autosomal dominant spinocerebellar degeneration associated with pigmental retinopathy. The proband is a 75-year-old man. He noticed night blindness at the age of 10 years and a diagnosis of bilateral pigmentary retinopathy was made at age 63. At the age of 65 years, he developed dysarthria and difficulty in walking. At age 69, neurological examination revealed cerebellar signs, and brain CT scans showed mild atrophy of the brain stem and cerebellum. Repeated brain CT scans revealed slight progression of the brain stem and cerebellar atrophy. Molecular genetic studies showed the absence of any mitochondrial DNA mutation at 8993. The father of the proband exhibited cerebellar signs and pigmentary retinopathy. One older brother had cerebellar signs and another had pigmentary retinopathy. To our knowledge, hereditary spinocerebellar degeneration with retinal degeneration is rare in Japan. This study is the first full report on hereditary spinocerebellar degeneration with pigmentary retinopathy in Japan, although an abstract was published by Konishi et al. We also discuss the neuropathological discordance on hereditary olivoponto-cerebellar atrophy with retinal degeneration.

Toric intraocular lenses: correcting astigmatism while controlling axis shift

We evaluated the efficacy of toric intraocular lenses (IOLs) implanted in the eyes of 47 patients who had preoperative against-the -rule astigmatism. The lenses, which had a cylinder power of 2.00 diopters (D) (n = 26) or 3.00 D (n = 21), were implanted through a 5.7 mm incision after cataract extraction by phacoemulsification. Best corrected visual acuity three months postoperatively was 20/25 or better in 77% of eyes. The 3.00 D IOLs resulted in better correction than the 2.00 D IOLs when the axis shift of the lens was less than 30 degrees. A negative effect occurred in some eyes in which the lens axis rotated more than 30 degrees. The maximum acceptable axis shift seems to be less than 30 degrees.

Nonstationary simulation of nonlinearly coupled TE-TM waves propagating down dielectric slab structures by the step-by-step finite-element method

Propagation phenomena of two nonlinearly coupled orthogonal waves in a slab waveguide are demonstrated numerically. It is shown that the propagation behavior is strongly dependent on the particular nonlinear mechanism as well as on the optical power allotted to each polarization component.