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1.
Adv Radiat Oncol ; 9(2): 101356, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38405309

ABSTRACT

Purpose: This study compares the dosimetric performance of the field-in-field (FIF) technique with intensity modulated radiation therapy (IMRT) for delivering hypofractionated radiation therapy to prostate patients with cancer. The FIF technique uses 6 beams, whereas IMRT uses 9 beams. Methods and Materials: This study was conducted on 15 patients with prostate cancer treated with step-and-shoot IMRT. The prescribed dose was 60 Gy in 20 fractions. The FIF plans contained 6 photon beams, and IMRT plans were designed using a 9-field step-and-shoot technique. Dose-volume histograms and dose distributions were evaluated to compare FIF and IMRT. Results: The results of the planning target volume indices analysis showed a significant difference in the maximum dose, dose to 2% of volume, and homogeneity index in favor of FIF and in the mean dose, dose to 98% of volume, and D95 in favor of IMRT. The results of the organs-at-risk analysis showed significant differences in the volume of the rectum and bladder receiving 60 Gy in favor of FIF and the volume of the rectum and femoral heads receiving 30 Gy, as well as the mean dose to the rectum, in favor of IMRT. IMRT had a higher median number of monitor units (MUs) and segments (886 MU, 64 segments) compared to FIF (434 MUs, 6 segments). Conclusions: The FIF technique and IMRT had comparable results in delivering hypofractionated radiation therapy for prostate cancer. The findings of this study may aid in decision-making for patients undergoing treatment.

2.
Heliyon ; 9(5): e15749, 2023 May.
Article in English | MEDLINE | ID: mdl-37305516

ABSTRACT

The plasmonic antenna probe is constructed using a silver rod embedded in a modified Mach-Zehnder interferometer (MZI) ad-drop filter. Rabi antennas are formed when space-time control reaches two levels of system oscillation and can be used as human brain sensor probes. Photonic neural networks are designed using brain-Rabi antenna communication, and transmissions are connected via neurons. Communication signals are carried by electron spin (up and down) and adjustable Rabi frequency. Hidden variables and deep brain signals can be obtained by external detection. A Rabi antenna has been developed by simulation using computer simulation technology (CST) software. Additionally, a communication device has been developed that uses the Optiwave program with Finite-Difference Time-Domain (OptiFDTD). The output signal is plotted using the MATLAB program with the parameters of the OptiFDTD simulation results. The proposed antenna oscillates in the frequency range of 192 THz to 202 THz with a maximum gain of 22.4 dBi. The sensitivity of the sensor is calculated along with the result of electron spin and applied to form a human brain connection. Moreover, intelligent machine learning algorithms are proposed to identify high-quality transmissions and predict the behavior of transmissions in the near future. During the process, a root mean square error (RMSE) of 2.3332(±0.2338) was obtained. Finally, it can be said that our proposed model can efficiently predict human mind, thoughts, behavior as well as action/reaction, which can be greatly helpful in the diagnosis of various neuro-degenerative/psychological diseases (such as Alzheimer's, dementia, etc.) and for security purposes.

3.
J Med Phys ; 48(1): 38-42, 2023.
Article in English | MEDLINE | ID: mdl-37342603

ABSTRACT

Purpose: The aim of this study was to investigate demographic and dosimetric parameters which may link with esophagitis in patients with breast cancer receiving three-dimensional conformal radiotherapy to the supraclavicular fossa. Materials and Methods: We examined 27 breast cancer patients with supraclavicular metastases. All patients were treated with radiotherapy (RT) with a prescribed dose of 40.5 Gy in 15 fractions for 3 weeks. Esophagitis was recorded weekly and esophagus toxicity was evaluated and graded according to the tadiation therapy oncology group. The following factors were examined regarding their correlation with grade 1 or worse esophagitis by univariate and multivariate analyses: age, chemotherapy, smoking history, maximum dose (Dmax), mean dose (Dmean), esophagus volume receiving 10 Gy (V10), esophagus volume receiving 20 Gy (V20), and length of esophagus in the treatment field. Results: Of 27, 11 (40.7%) patients developed no esophageal irritation throughout therapy. Approximately half of the patients 13/27 (48.1%) had maximum grade 1 esophagitis. 2/27 (7.4%) patients had grade 2 esophagitis. The incidence of grade 3 esophagitis was (3.7%). Dmean, Dmax, V10, and V20 were 10.48 ± 5.10 Gy, 38.18 ± 5.12Gy, 29.83 ± 15.16, and 19.32 ± 10.01, respectively. Our results showed that Dmean, V10, and V20 were the significant factors for the development of esophagitis, whereas esophagitis was not significantly associated with the chemotherapy regimen, age, and smoking status. Conclusions: We found that Dmean, V10, and V20 correlated significantly with acute esophagitis. However, the chemotherapy regimen, age, and smoking status did not affect esophagitis development.

4.
Appl Opt ; 60(16): 4544-4556, 2021 Jun 01.
Article in English | MEDLINE | ID: mdl-34143008

ABSTRACT

These days when integrated circuit (IC) designers are facing an uphill task in limiting energy/heat dissipation, reversible computing is emerging as a potential candidate with vast application in fields like nanotechnology, quantum-dot cellular automata, and low power IC. Optical reversible logics have turned up to offer high speed and low energy computations with almost no loss of input information when a certain (arithmetic or logical) operation is performed. This paper explores an optical implementation of an optimized Fredkin gate that is employed to design an $ N:2^N $ reversible decoder. The optical designs have been carried out using the electro-optic effect of a lithium niobate ($ {{\rm LiNbO}_3}$)-based Mach-Zehnder interferometer under the beam propagation method (BPM) with Optiwave's OptiBPM tool. The mathematical model of output power of these designs is also performed along with its validation in MATLAB.

5.
Gulf J Oncolog ; 1(35): 36-41, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33716211

ABSTRACT

BACKGROUNDS: Breast cancer represents the second most frequent cause of brain metastases after lung cancer. Previous studies have identified the subgroups of patients with triple-negative and HER2-positive as having an increased risk for the development of brain metastases. We are not aware in Kurdistan - Iraq of any national studies that are in parallel with these findings. PATIENTS AND METHODS: A cross-sectional descriptive study conducted on 57 patients who were known cases of breast cancer with brain metastasis, managed with whole brain radiotherapy at a tertiary radiotherapy institute in two years (January 2015 to December 2016), as a convenient sample. Data were collected from patients' archives and phone calls and then analyzed using SPSS version 23. RESULTS: Younger age at diagnosis and cancers with HER2-positive receptor phenotype are risk factors for brain metastasis. Median survival post-brain metastasis is significantly affected by receptor phenotypes (2 months in triple negative versus 7 months in hormone receptor positive) and performance status (18 months if performance score of 70% and above versus 1.5 months if it is 60% and less). CONCLUSION: Primary breast cancer patients have more risk to develop brain metastases if they are at younger age and HER2-positive and the survival post-brain metastases is dramatically affected by both triple negative receptor phenotype and lower performance score.


Subject(s)
Breast Neoplasms/radiotherapy , Adult , Cross-Sectional Studies , Female , Humans , Middle Aged , Middle East , Neoplasm Metastasis , Prognosis , Risk Factors , Young Adult
6.
Gulf J Oncolog ; 1(33): 51-57, 2020 May.
Article in English | MEDLINE | ID: mdl-32476650

ABSTRACT

PURPOSE: Laryngeal cancer is relatively common and usually presents with hoarseness due to a lesion in the glottis. We noticed that many of our patients had presented with supraglottic lesions and we could not find local literature in support of this observation. Mode of presentation and site of the lesion of these patients will be addressed in this review. MATERIALS AND METHODS: A retrospective cross-sectional descriptive study for laryngeal cancer patients who received radiotherapy at a tertiary radiotherapy center in Iraq, from January 2010 to December 2015, and who are residents in the Sulaimani governorate. RESULTS: In 6 years, laryngeal cancer patients from Sulaimani were 83 (out of 123 in total), which constituted the most common, 40.8%, head and neck cancers. 86.7% were males and the median age was 68.3 year. Most common presentation was hoarseness, 79.5%, and the least was dysphagia and stridor, 28.9%. Pain and neck swelling were found in 51.8%, 34.9%, respectively. Site of the cancer lesions were in supraglottis in 53%, glottis in 32.5%, transglottis in 8.4%, and subglottis in 6%. Commonest stage was IVA in 54.2% while the least was IVB 2.4%. Squamous cell carcinoma was the pathological type in all of our patients. CONCLUSION: Laryngeal cancer is the most common head and neck cancer in our institutional registry. While all the pathologies were of squamous cell carcinoma, hoarseness was the most common presentation and supraglottis was the most common site of involvement.


Subject(s)
Laryngeal Neoplasms/radiotherapy , Aged , Cross-Sectional Studies , Female , Humans , Iraq , Male , Retrospective Studies
7.
Mater Sci Eng C Mater Biol Appl ; 103: 109863, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31349467

ABSTRACT

Quick setting and poor injectability due to liquid-solid phase separation have limited the clinical use of brushite and monetite cements. The presence of certain ions in the cement during the setting reaction moderate the setting time and properties of the cement. This study reports the preparation of injectable bone cement by using biphasic calcium phosphate (BCP) extracted from femur lamb bone by calcination at 1450 °C. EDX analysis infers the presence of Mg and Na ions as trace elements in BCP. X-ray diffraction patterns of the prepared cement confirmed the formation of brushite (DCPD) along with monetite (DCPA) as a minor phase. DCPA phase diminished gradually with a decrease in powder to liquid ratio (PLR). Initial and final setting time of 5.3 ±â€¯0.5 and 14.67 ±â€¯0.5 min respectively are obtained and within the acceptable recommended range for orthopedic applications. Exceptional injectability of ≈90% is achieved for all prepared bone cement samples. A decrease in compressive strength was observed with increase in the liquid phase of the cement, which is attributed to the higher degree of porosity in the set cement. Immersion of bone cement in simulated body fluid (SBF) for up to 7 days resulted in the formation of apatite layer on the surface of cement with Ca/P ratio 1.71, which enhanced the compressive strength from 2.88 to 9.15 MPa. The results demonstrate that bone cement produced from BCP extracted from femur lamb bone can be considered as potential bone substitute for regeneration and repair of bone defects.


Subject(s)
Bone Cements , Bone Substitutes , Calcium Phosphates/chemistry , Femur/chemistry , Hydroxyapatites/chemistry , Animals , Bone Cements/chemical synthesis , Bone Cements/chemistry , Bone Substitutes/chemical synthesis , Bone Substitutes/chemistry , Sheep
8.
Biosystems ; 183: 103982, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31195028

ABSTRACT

We have further developed the two-brains hypothesis as a form of complementarity (or complementary relationship) of endogenously induced weak magnetic fields in the electromagnetic brain. The locally induced magnetic field between electron magnetic dipole moments of delocalized electron clouds in neuronal domains is complementary to the exogenous electromagnetic waves created by the oscillating molecular dipoles in the electro-ionic brain. In this paper, we mathematically model the operation of the electromagnetic grid, especially in regard to the functional role of atomic orbitals of dipole-bound delocalized electrons. A quantum molecular dynamic approach under quantum equilibrium conditions is taken to illustrate phase differences between quasi-free electrons tethered to an oscillating molecular core. We use a simplified version of the many-body problem to analytically solve the macro-quantum wave equation (equivalent to the Kohn-Sham equation). The resultant solution for the mechanical angular momentum can be used to approximate the molecular orbital of the dipole-bound delocalized electrons. In addition to non-adiabatic motion of the molecular core, 'guidance waves' may contribute to the delocalized macro-quantum wave functions in generating nonlocal phase correlations. The intrinsic magnetic properties of the origins of the endogenous electromagnetic field are considered to be a nested hierarchy of electromagnetic fields that may also include electromagnetic patterns in three-dimensional space. The coupling between the two-brains may involve an 'anticipatory affect' based on the conceptualization of anticipation as potentiality, arising either from the macro-quantum potential energy or from the electrostatic effects of residual charges in the quantum and classical subsystems of the two-brains that occurs through partitioning of the potential energy of the combined quantum molecular dynamic system.


Subject(s)
Brain/physiology , Electrons , Neurons/physiology , Animals , Cognition , Computer Simulation , Electromagnetic Fields , Fourier Analysis , Humans , Ions , Models, Neurological , Models, Theoretical , Molecular Dynamics Simulation , Quantum Theory
9.
J Nanosci Nanotechnol ; 19(7): 4142-4146, 2019 Jul 01.
Article in English | MEDLINE | ID: mdl-30764983

ABSTRACT

Aluminium substituted cobalt-copper Co1-xCuxFe2-xAlxO4, (x ═ 0.8) nanoparticles are grown and sintered at different temperature in the range 600 to 900 °C. XRD analysis on nanoparticles prepared at sintered temperatures of 700 °C and 800 °C confirms the spinel structure and presence of hematite phase (alpha ferrite) in them. The dielectric behaviour of the prepared nano-particles is investigated. Although crystallinity improved with increase in sintering temperature and there was a dielectric loss at higher probe analyser frequency. The synthesized nanoparticles an average particle size of 20-24 nm while the FTIR absorption in regions of 586-595 cm-1 and 450-460 cm-1 indicated the presence of intrinsic vibrations of the tetrahedral and octahedral complexes respectively. Electrical resistivity as a function of temperature confirms the semiconducting nature of the Cu-Al substituted cobalt ferrite, and is attributed to the hopping mechanism between Fe2+ Fe3+ ions and Co2+ Cu2+, Co2+ Al3+. The lower values of dielectric constants and dielectric losses make Al-Cu doped cobalt ferrite, a potential material for microwave and radio wave absorber applications.

10.
J Glob Oncol ; 5: 1-9, 2019 01.
Article in English | MEDLINE | ID: mdl-30707662

ABSTRACT

PURPOSE: Ewing sarcoma (ES) is a relatively rare, highly malignant tumor of the musculoskeletal system. It is the second most common malignant bone tumor in children and adolescents in the age group of 5 to 20 years. The aim of this study was to identify the treatment outcomes of pediatric patients with ES in Sulaimani governorate, Iraq. PATIENTS AND METHODS: This was a retrospective study that reviewed the medical records of pediatric patients with ES who were managed between 2009 and 2015, with follow-up until late 2017. Patient- and tumor-related factors were correlated with clinical outcomes. RESULTS: A total of 31 pediatric patients with ES were included in this study. All the patients received chemotherapy and radiotherapy, whereas only 14 patients underwent surgical resection and just eight had free surgical margins. The median age at diagnosis was 13 years, 58% were male, and 42% were female. The presenting symptoms at diagnosis were mostly pain (67.7%) and palpable mass (25.8%). The primary tumor was located in the extremities (51.6%), the thoracic cage (19.4%), the pelvis (16.1%), and the lumbar vertebrae (12.9%). Approximately two thirds of the patients (61.3%) had localized disease at the time of presentation. The 5-year overall survival was 19%, and the 5-year recurrence-free survival was 34%. CONCLUSION: Clinical outcomes of ES in pediatric patients in our war-torn nation, Iraq, are still markedly inferior to the published outcomes from stable, developed nations. Additional large and multicenter national studies are required. Diagnostic and therapeutic measures need improvement, and multidisciplinary and comprehensive cancer-integrated approaches are vital for better outcomes.


Subject(s)
Bone Neoplasms/therapy , Sarcoma, Ewing/therapy , War Exposure/statistics & numerical data , Adolescent , Bone Neoplasms/mortality , Bone Neoplasms/pathology , Chemoradiotherapy , Combined Modality Therapy , Female , Humans , Iraq/epidemiology , Male , Retrospective Studies , Sarcoma, Ewing/mortality , Sarcoma, Ewing/pathology , Surgical Procedures, Operative/statistics & numerical data , Survival Rate , Treatment Outcome
11.
Micromachines (Basel) ; 9(9)2018 Sep 11.
Article in English | MEDLINE | ID: mdl-30424385

ABSTRACT

Light has found applications in data transmission, such as optical fibers and waveguides and in optoelectronics. It consists of a series of electromagnetic waves, with particle behavior. Photonics involves the proper use of light as a tool for the benefit of humans. It is derived from the root word "photon", which connotes the tiniest entity of light analogous to an electron in electricity. Photonics have a broad range of scientific and technological applications that are practically limitless and include medical diagnostics, organic synthesis, communications, as well as fusion energy. This will enhance the quality of life in many areas such as communications and information technology, advanced manufacturing, defense, health, medicine, and energy. The signal transmission methods used in wireless photonic systems are digital baseband and RoF (Radio-over-Fiber) optical communication. Microwave photonics is considered to be one of the emerging research fields. The mid infrared (mid-IR) spectroscopy offers a principal means for biological structure analysis as well as nonintrusive measurements. There is a lower loss in the propagations involving waveguides. Waveguides have simple structures and are cost-efficient in comparison with optical fibers. These are important components due to their compactness, low profile, and many advantages over conventional metallic waveguides. Among the waveguides, optofluidic waveguides have been found to provide a very powerful foundation for building optofluidic sensors. These can be used to fabricate the biosensors based on fluorescence. In an optical fiber, the evanescent field excitation is employed to sense the environmental refractive index changes. Optical fibers as waveguides can be used as sensors to measure strain, temperature, pressure, displacements, vibrations, and other quantities by modifying a fiber. For some application areas, however, fiber-optic sensors are increasingly recognized as a technology with very interesting possibilities. In this review, we present the most common and recent applications of the optical fiber-based sensors. These kinds of sensors can be fabricated by a modification of the waveguide structures to enhance the evanescent field; therefore, direct interactions of the measurand with electromagnetic waves can be performed. In this research, the most recent applications of photonics components are studied and discussed.

12.
J Geriatr Oncol ; 9(4): 346-351, 2018 07.
Article in English | MEDLINE | ID: mdl-29598913

ABSTRACT

INTRODUCTION: Cancer prevalence and geriatric patients (GP) are increasing and about half of the patients with cancer will be offered radiotherapy (RT). Addressing GP and their RT needs is an important issue in order to understand this heterogeneous group of patients. MATERIALS AND METHODS: A descriptive cross-sectional study, using a convenience sample from Sulaimani city's inhabitants, aged 70-year and more, who were treated with RT at the only city's RT center, Zhianawa Cancer Center (ZCC), in 2015. RESULTS: 153 patients' charts were reviewed. GP represented 20% of the patients referred to ZCC. Male: Female ratio was 3:1. One third presented with distant metastases, and 46% were treated with curative intent versus 54% with palliative intent. 94% completed the planned sessions of the curative RT vs 90% of the palliative RT. 23% of GP who were referred for RT didn't receive it. 9% got interruptions during RT course. 10% of GP living >40 km away from the treatment center refused treatment. Mean time interval between the date of referral and the date of starting treatment in the palliative setting was 19 days. Only 41% of patients with curative setting had regular follow-up. CONCLUSIONS: Being the 1st study in this regard in a war-torn nation, Iraq, our results demonstrated that GP is a sizable group of ZCC patients and that RT is a valuable modality in GP cancer treatment. "Age per se" is not a factor to avoid this modality when there is an indication to use it. Longer distance to reach the center was a challenge in some of our GP. Due to inadequate number of RT machines, GP have to wait long time before getting their RT, even for palliative purposes. Further studies in this field are warranted.


Subject(s)
Frailty/diagnosis , Geriatric Assessment/methods , Neoplasms/radiotherapy , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Health Services Accessibility , Humans , Iraq/epidemiology , Karnofsky Performance Status , Male , Neoplasm Staging , Neoplasms/mortality , Palliative Care/statistics & numerical data , Warfare
13.
Artif Cells Nanomed Biotechnol ; 44(1): 315-21, 2016.
Article in English | MEDLINE | ID: mdl-25133457

ABSTRACT

A new microring resonator system is proposed for the detection of the Salmonella bacterium in drinking water, which is made up of SiO2-TiO2 waveguide embedded inside thin film layer of the flagellin. The change in refractive index due to the binding of the Salmonella bacterium with flagellin layer causes a shift in the output signal wavelength and the variation in through and drop port's intensities, which leads to the detection of Salmonella bacterium in drinking water. The sensitivity of proposed sensor for detecting of Salmonella bacterium in water solution is 149 nm/RIU and the limit of detection is 7 × 10(-4)RIU.


Subject(s)
Biosensing Techniques/instrumentation , Flagellin/chemistry , Optical Devices , Salmonella typhimurium/isolation & purification , Biosensing Techniques/methods , Drinking Water/microbiology , Humans , Limit of Detection , Silicon Dioxide/chemistry , Titanium/chemistry
14.
Sci Rep ; 5: 8551, 2015 Feb 25.
Article in English | MEDLINE | ID: mdl-25711343

ABSTRACT

Terahertz technologies recently emerged as outstanding candidates for a variety of applications in such sectors as security, biomedical, pharmaceutical, aero spatial, etc. Imaging the terahertz field, however, still remains a challenge, particularly when sub-wavelength resolutions are involved. Here we demonstrate an all-optical technique for the terahertz near-field imaging directly at the source plane. A thin layer (<100 nm-thickness) of photo carriers is induced on the surface of the terahertz generation crystal, which acts as an all-optical, virtual blade for terahertz near-field imaging via a knife-edge technique. Remarkably, and in spite of the fact that the proposed approach does not require any mechanical probe, such as tips or apertures, we are able to demonstrate the imaging of a terahertz source with deeply sub-wavelength features (<30 µm) directly in its emission plane.

15.
ScientificWorldJournal ; 2014: 294104, 2014.
Article in English | MEDLINE | ID: mdl-24977191

ABSTRACT

Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrast enhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrast enhancement introduces the concept of "adequate contrast enhancement" to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrast enhancement checks on the image's maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher's Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrast enhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection.


Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Osteoarthritis, Knee/pathology , Data Interpretation, Statistical , Humans , Reproducibility of Results , Sensitivity and Specificity
16.
Sensors (Basel) ; 14(7): 12885-99, 2014 Jul 18.
Article in English | MEDLINE | ID: mdl-25046015

ABSTRACT

A new photonics biosensor configuration comprising a Double-side Ring Add-drop Filter microring resonator (DR-ADF) made from SiO2-TiO2 material is proposed for the detection of Salmonella bacteria (SB) in blood. The scattering matrix method using inductive calculation is used to determine the output signal's intensities in the blood with and without presence of Salmonella. The change in refractive index due to the reaction of Salmonella bacteria with its applied antibody on the flagellin layer loaded on the sensing and detecting microresonator causes the increase in through and dropper port's intensities of the output signal which leads to the detection of SB in blood. A shift in the output signal wavelength is observed with resolution of 0.01 nm. The change in intensity and shift in wavelength is analyzed with respect to the change in the refractive index which contributes toward achieving an ultra-high sensitivity of 95,500 nm/RIU which is almost two orders higher than that of reported from single ring sensors and the limit of detection is in the order of 1 × 10(-8) RIU. In applications, such a system can be employed for a high sensitive and fast detection of bacteria.


Subject(s)
Biosensing Techniques/methods , Blood/microbiology , Equipment Design/methods , Salmonella/chemistry , Equipment Failure Analysis/methods , Humans , Nanotechnology/methods , Optics and Photonics/methods , Refractometry/methods , Silicon Dioxide/chemistry , Titanium/chemistry
17.
Appl Opt ; 52(12): 2866-73, 2013 Apr 20.
Article in English | MEDLINE | ID: mdl-23669699

ABSTRACT

In this paper, the bifurcation behavior of light in the PANDA ring resonator is investigated using the signal flow graph (SFG) method, where the optical transfer function for the through and drop ports of the PANDA Vernier system are derived. The optical nonlinear phenomena, such as bistability, Ikeda instability, and dynamics of light in the silicon-on-insulator (SOI) PANDA ring resonator with four couplers are studied. The transmission curves for bistability and instability as a function of the resonant mode numbers and coupling coefficients for the coupler are derived by the SFG method and simulated. The proposed system has an advantage as no optical pumping component is required. Simulated results show that closed-loop bistable switching can be generated and achieved by varying mode resonant numbers in the SOI-PANDA Vernier resonator, where a smooth and closed-loop bistable switching with low relative output/input power can be obtained and realized. The minimum through-port switching time of 1.1 ps for resonant mode numbers of 5;4;4 and minimum drop port switching time of 1.96 ps for resonant mode numbers of 9;7;7 of the PANDA Vernier resonator are achieved, which makes the PANDA Vernier resonator an operative component for optical applications, such as optical signal processing and a fast switching key in photonics integrated circuits.

18.
Artif Cells Nanomed Biotechnol ; 41(6): 368-75, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23305176

ABSTRACT

A novel design of nerve communications and networks using the coupling effects between bio-cells and optical dipoles is proposed. The electrical signals are coupled to the dipoles and cells which propagate within the optical networks for long distance without any electromagnetic interference. Results have shown that the use of optical spins in the spin networks, referred as Spinnet, can be formed. This technique can be used to improve the nerve communication performance. It is fabricated as a nano-biotic circuit system, and has great potential for future disability applications and diagnosis of the links of nerves across the dead cells.


Subject(s)
Cell Communication , Electrophysiological Phenomena , Models, Neurological , Neurons/cytology , Optical Phenomena
19.
Appl Opt ; 51(21): 5111-8, 2012 Jul 20.
Article in English | MEDLINE | ID: mdl-22858951

ABSTRACT

A new method of photodetector performance enhancement using an embedded optical accelerator circuit within the photodetector is proposed. The principle of optical tweezer generation using a light pulse within a PANDA ring is also reviewed. By using a modified add-drop optical filter known as a PANDA microring resonator, which is embedded within the photodetector circuit, the device performance can be improved by using an electron injection technique, in which electrons can be trapped by optical tweezers generated by a PANDA ring resonator. Finally, electrons can move faster within the device via the optical waveguide without trapping center in the silicon bulk to the contact, in which the increase in photodetector current is seen. Simulation results obtained have shown that the device's light currents are increased by the order of four, and the switching time is increased by the order of five. This technique can be used for better photodetector performance and other semiconductor applications in the future.

20.
Int J Nanomedicine ; 7: 2873-81, 2012.
Article in English | MEDLINE | ID: mdl-22745550

ABSTRACT

Auscultation of the heart is accompanied by both electrical activity and sound. Heart auscultation provides clues to diagnose many cardiac abnormalities. Unfortunately, detection of relevant symptoms and diagnosis based on heart sound through a stethoscope is difficult. The reason GPs find this difficult is that the heart sounds are of short duration and separated from one another by less than 30 ms. In addition, the cost of false positives constitutes wasted time and emotional anxiety for both patient and GP. Many heart diseases cause changes in heart sound, waveform, and additional murmurs before other signs and symptoms appear. Heart-sound auscultation is the primary test conducted by GPs. These sounds are generated primarily by turbulent flow of blood in the heart. Analysis of heart sounds requires a quiet environment with minimum ambient noise. In order to address such issues, the technique of denoising and estimating the biomedical heart signal is proposed in this investigation. Normally, the performance of the filter naturally depends on prior information related to the statistical properties of the signal and the background noise. This paper proposes Kalman filtering for denoising statistical heart sound. The cycles of heart sounds are certain to follow first-order Gauss-Markov process. These cycles are observed with additional noise for the given measurement. The model is formulated into state-space form to enable use of a Kalman filter to estimate the clean cycles of heart sounds. The estimates obtained by Kalman filtering are optimal in mean squared sense.


Subject(s)
Algorithms , Phonocardiography/methods , Signal Processing, Computer-Assisted , Heart Murmurs/physiopathology , Heart Sounds/physiology , Humans , Signal-To-Noise Ratio
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