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1.
Braz J Biol ; 84: e280855, 2024.
Article in English | MEDLINE | ID: mdl-38422303

ABSTRACT

Medicinal plants hold significant cultural significance and play a crucial role in the advancement of potentially safe drugs for the therapy of disease worldwide. Pennisetum purpureum or elephant grass has been used for traditional medications in Indonesia without understanding the phytochemicals of those plants. Herein, our report revolves around the qualitative and quantitative examination of phytochemical components, optical properties, antioxidants, and antibacterial assessments of solvent fractions derived from Pennisetum purpureum leaf. The Pennisetum purpureum leaf was successfully soaked with ethanol, n-hexane, and chloroform. The study aimed to assess the total phenolic content (TPC), total flavonoid content (TFC), and total alkaloid content (TAC) within different of extracts. The optical properties of extract were analyzed by absorption light and photoluminescent. Moreover, evaluation of antioxidant activities of extracts through DPPH free radical scavenging and FRAP assays, followed by an evaluation of their effectiveness in antibacterial therapy against different bacterial strains. The qualitative and quantitative phytochemical of Pennisetum purpureum presented as highest in ethanol TPC (85.5 mg GAE/g extracts), TFC (87.9 mg QE/g extracts), and TAC (86.2 mg ATE/g extracts) as compared to other solvents extract. Pennisetum purpureum extract had antioxidant capacity against DPPH radical and FRAP assay. Furthermore, each of the samples displayed antibacterial effectiveness that was dependent on the dosage towards different strains of bacteria. Our findings clearly demonstrated that Pennisetum purpureum leaf extracts grown in Indonesia containing alkaloid, flavonoid, glycoside, saponin, steroids, tannin, and terpenoids that support its capability as antioxidant and antibacterial.


Subject(s)
Alkaloids , Optical Devices , Pennisetum , Antioxidants/pharmacology , Plant Extracts/pharmacology , Plant Extracts/chemistry , Indonesia , Anti-Bacterial Agents/pharmacology , Phytochemicals , Flavonoids/pharmacology , Ethanol
2.
Anal Chem ; 95(35): 13385-13390, 2023 09 05.
Article in English | MEDLINE | ID: mdl-37622311

ABSTRACT

The development of liquid crystal (LC)-based sensors with superior performances such as high portability, excellent stability, great convenience, and remarkable sensitivity is highly demanded. This work proposes a new strategy for constructing the LC-based sensor using enzyme-linked dual-functional nucleic acid (d-FNA) on magnetic beads (MBs). The detection of kanamycin (KA) is demonstrated as a model. Acetylcholinesterase (AChE) is assembled onto the KA aptamer-modified MBs with a d-FNA strand that consists of an AChE aptamer and the complementary sequence of a KA aptamer. As the specific recognition of KA by its aptamer triggers the release of AChE from the MBs, the myristoylcholine (Myr) solution after incubation with the MBs causes the black image of the LCs due to the formation of the Myr monolayer at the aqueous/LC interface. Otherwise, in the absence of KA, AChE is still decorated on the MBs and causes the hydrolysis of Myr. Therefore, a bright image of LCs is obtained. The detection of KA is successfully achieved with a lower detection limit of 48.1 pg/mL. In addition, a thin polydimethylsiloxane (PDMS) layer-coated glass and a portable optical device are used to improve the stability and portability of the LC-based sensor to advance potential commercial applications. Furthermore, the detection of KA in milk with a portable device is demonstrated, showing the potential of the proposed enzyme-linked LC-based sensor.


Subject(s)
Liquid Crystals , Nucleic Acids , Optical Devices , Acetylcholinesterase , Kanamycin , Oligonucleotides , Magnetic Phenomena
3.
Sensors (Basel) ; 23(4)2023 Feb 05.
Article in English | MEDLINE | ID: mdl-36850384

ABSTRACT

This article describes chemical and physical parameters, including their role in the storage, trade, and processing of potatoes, as well as their nutritional properties and health benefits resulting from their consumption. An analysis of the share of losses occurring during the production process is presented. The methods and applications used in recent years to estimate the physical and chemical parameters of potatoes during their storage and processing, which determine the quality of potatoes, are presented. The potential of the technologies used to classify the quality of potatoes, mechanical and ultrasonic, and image processing and analysis using vision systems, as well as their use in applications with artificial intelligence, are discussed.


Subject(s)
Optical Devices , Solanum tuberosum , Artificial Intelligence , Image Processing, Computer-Assisted , Technology
4.
Anal Chem ; 94(22): 8058-8065, 2022 06 07.
Article in English | MEDLINE | ID: mdl-35611971

ABSTRACT

The detection and therapy of cancers in the early stage significantly alleviate the associated dangers. Optical devices offer new opportunities for these early measures. However, the clinical translation of the existing methods is severely hindered by their relatively low sensitivity or unclear physiological metabolism. Here, an optical microfiber sensor with a drug loading gold nanorod-black phosphorous nanointerface, as an ultrasensitive biosensor and nanotherapy platform, is developed to meet the early-stage requirement. With interface sensitization and functionalization of the hybrid nanointerface, the microfiber sensor presents an ultrahigh sensing performance, achieving the selective detection of the HER2 biomarker with limits of detection of 0.66 aM in buffer solution and 0.77 aM in 10% serum. It can also distinguish breast cancer cells from other cells in the early stage. Additionally, enabled by the interface, the optical microfiber is able to realize cellular nanotherapy, including photothermal/chemotherapy with pump laser coupling after diagnosis, and evaluate therapy results in real time. The immobilization of the interface on the optical microfiber surface prevents the damage to normal cells induced by nanomaterial enrichment, making the device more efficient and intelligent. This study opens up a new avenue for the development of smart optical platforms for sensitive biosensing and precision therapy.


Subject(s)
Biosensing Techniques , Nanotubes , Optical Devices , Gold , Phosphorus
5.
Chem Soc Rev ; 50(4): 2260-2279, 2021 Mar 01.
Article in English | MEDLINE | ID: mdl-33367452

ABSTRACT

Pnictogens (the non-metal phosphorus, metalloids arsenic and antimony, and metal bismuth) possess diverse chemical characteristics that support the formation of extended molecular structures. As witnessed by the centuries-old (and ongoing) clinical utilities, pnictogen-based compounds have secured their places in history as "magic bullet" therapeutic drugs in medicinal contexts. Moreover, with the development of recent metalloproteomics and bio-coordination chemistry, the pnictogen-based drugs functionally binding to proteins/enzymes in biological systems have been underlaid for "drug repurposing" with promising opportunities. Furthermore, advances in the modern materials science and nonotechnology have stimulated a revolution in other newly discovered forms of pnictogens-phosphorene, arsenene, antimonene, and bismuthine (layered pnictogens). Based on their favorable optoelectronic properties, layered pnictogens have shown dramatic superiority as emerging photonic nanomedicines for the treatment of various diseases. This tutorial review outlines the history and mechanism of action of ancient pnictogen-based drugs (e.g., arsenical compounds in traditional Chinese medicine) and their repurposing into modern therapeutics. Then, the revolutionary use of emerging layered pnictogens as photonic nanomedicines, alongside assessments of their in vivo biosafety, is discussed. Finally, the challenges to further development of pnictogens are set forth and insights for further exploration of their appealing properties are offered. This tutorial review may also provide some deep insights into the fields of integrated traditional Chinese and Western medicines from the perspective of materials science and nanotechnology.


Subject(s)
Antimony/chemistry , Arsenicals/chemistry , Bismuth/chemistry , Nanostructures/chemistry , Pharmaceutical Preparations/chemistry , Phosphorus Compounds/chemistry , Animals , Antimony/pharmacology , Arsenicals/pharmacology , Biocompatible Materials/chemistry , Bismuth/pharmacology , Humans , Immunotherapy , Molecular Structure , Nanomedicine , Optical Devices , Phosphorus Compounds/pharmacology , Phototherapy , Protein Binding , Radiotherapy
6.
Sensors (Basel) ; 20(14)2020 Jul 17.
Article in English | MEDLINE | ID: mdl-32709072

ABSTRACT

Optical waveguides and integrated optical devices are promising solutions for many applications, such as medical diagnosis, health monitoring and light therapies. Despite the many existing reviews focusing on the materials that these devices are made from, a systematic review that relates these devices to the various materials, fabrication processes, sensing methods and medical applications is still seldom seen. This work is intended to link these multidisciplinary fields, and to provide a comprehensive review of the recent advances of these devices. Firstly, the optical and mechanical properties of optical waveguides based on glass, polymers and heterogeneous materials and fabricated via various processes are thoroughly discussed, together with their applications for medical purposes. Then, the fabrication processes and medical implementations of integrated passive and active optical devices with sensing modules are introduced, which can be used in many medical fields such as drug delivery and cardiovascular healthcare. Thirdly, wearable optical sensing devices based on light sensing methods such as colorimetry, fluorescence and luminescence are discussed. Additionally, the wearable optical devices for light therapies are introduced. The review concludes with a comprehensive summary of these optical devices, in terms of their forms, materials, light sources and applications.


Subject(s)
Optical Devices , Wearable Electronic Devices , Glass , Phototherapy , Polymers
7.
Sensors (Basel) ; 19(24)2019 Dec 09.
Article in English | MEDLINE | ID: mdl-31835391

ABSTRACT

Light emitting diode (LED) and ultrasound have been powerful treatment stimuli for tumor cell growth due to non-radiation effects. This research is the first preliminary study of tumor cell suppression using a macro-lens-supported 460-nm LED combined with high-frequency ultrasound. The cell density, when exposed to the LED combined with ultrasound, was gradually reduced after 30 min of induction for up to three consecutive days when 48-W DC, 20-cycle, and 50 Vp-p sinusoidal pulses were applied to the LEDs through a designed macro lens and to the ultrasound transducer, respectively. Using a developed macro lens, the non-directional light beam emitted from the LED could be localized to a certain spot, likewise with ultrasound, to avoid additional undesirable thermal effects on the small sized tumor cells. In the experimental results, compared to LED-only induction (14.49 ± 2.73%) and ultrasound-only induction (13.27 ± 2.33%), LED combined with ultrasound induction exhibited the lowest cell density (6.25 ± 1.25%). Therefore, our measurement data demonstrated that a macro-lens-supported 460-nm LED combined with an ultrasound transducer could possibly suppress early stage tumor cells effectively.


Subject(s)
Cell Tracking/methods , Neoplasms/diagnosis , Optical Devices , Cell Line, Tumor , Humans , Lenses , Light , Neoplasms/pathology , Ultrasonic Waves
8.
Lasers Med Sci ; 34(7): 1421-1431, 2019 Sep.
Article in English | MEDLINE | ID: mdl-30762195

ABSTRACT

To improve methods of laser hyperthermia for the treatment of bulk malignant neoplasms, an urgent task is the development of techniques and devices that automatically control heating at a given tissue depth and ensure its uniformity. The article proposes the concept of a system for performing hyperthermia with real-time spectroscopic temperature control and surface cooling, which allows to record spectra of diffusely scattered radiation and fluorescent signal from various depths of biological tissues by the means of the variation of the angle and distance between the fiber source of laser radiation and the receiving fiber. Theoretical and experimental modeling of the spatial distribution of diffusely scattered radiation and temperature inside the tissue with a fiber optic device providing surface cooling of the irradiated tissue, and recording spectral information from a given depth in real time, is presented. Simulation of radiation propagation in biological tissues, depending on the distance between the source and the receiver and the angle of their tilt, was carried out using the Monte Carlo method. Modeling of the temperature distribution inside the tissues was carried out by means of a numerical solution of the heat conduction equation. Experimental modeling was carried out on phantoms of biological tissues simulating their scattering properties as well as accumulation of the investigated nanoparticles doped with Nd3+ ions. It was shown that inorganic nanoparticles doped with rare-earth Nd3+ ions can be used as temperature labels for feedback to the therapeutic laser. According to the results of the theoretical simulation, optimal configurations of the relative arrangement of the fibers were chosen, as well as the optimum surface cooling temperatures for the given power densities. The heating of the phantom of the neoplasm containing the investigated nanoparticles doped with Nd3+ ions by laser radiation with an 805-nm wavelength and power density of 1 W/cm2 up to 42 °C at a depth of 1 cm while maintaining the surface temperature within the limits of the norm was demonstrated.


Subject(s)
Cold Temperature , Hyperthermia, Induced , Laser Therapy , Models, Theoretical , Nanoparticles/chemistry , Neodymium/chemistry , Luminescence , Monte Carlo Method , Neoplasms/therapy , Optical Devices , Phantoms, Imaging
9.
Nat Commun ; 9(1): 3550, 2018 09 03.
Article in English | MEDLINE | ID: mdl-30177699

ABSTRACT

Wide-field imaging of neural activity at a cellular resolution is a current challenge in neuroscience. To address this issue, wide-field two-photon microscopy has been developed; however, the field size is limited by the objective size. Here, we develop a micro-opto-mechanical device that rotates within the post-objective space between the objective and brain tissue. Two-photon microscopy with this device enables sub-second sequential calcium imaging of left and right mouse sensory forelimb areas 6 mm apart. When imaging the rostral and caudal motor forelimb areas (RFA and CFA) 2 mm apart, we found high pairwise correlations in spontaneous activity between RFA and CFA neurons and between an RFA neuron and its putative axons in CFA. While mice performed a sound-triggered forelimb-movement task, the population activity between RFA and CFA covaried across trials, although the field-averaged activity was similar across trials. The micro-opto-mechanical device in the post-objective space provides a novel and flexible design to clarify the correlation structure between distant brain areas at subcellular and population levels.


Subject(s)
Microscopy/instrumentation , Motor Cortex/cytology , Neurons/cytology , Optical Devices , Optical Imaging/instrumentation , Animals , Equipment Design , Forelimb , Mice , Microscopy/methods , Motor Cortex/anatomy & histology , Optical Imaging/methods
10.
J Biophotonics ; 11(1)2018 01.
Article in English | MEDLINE | ID: mdl-28731623

ABSTRACT

A basket-integrated optical device is developed to consistently treat tubular tissue by centering an optical diffuser in the lumen. Four nitinol arms in conjunction with the optical diffusing applicator are deployed to induce homogeneous circumferential light emission and concentric photothermal coagulation on tracheal tissue. A 1470-nm laser light is employed for the tissue testing at various irradiation conditions and evaluated in terms of thermal gradient and temperature evolution. Preliminary experiments on liver tissue demonstrate the concentric development of the radial thermal coagulation in the tissue (eccentric ratio = ~5.5%). The interstitial tissue temperature increases with the total amount of energy delivery (around 65°C). Ex vivo trachea testing yields up to 16.5% tissue shrinkage due to dehydration as well as uniform ablation of the cilia and goblet cells in a mucosa layer under 7-W irradiation for 10 s. The proposed optical device may be a feasible therapeutic method to entail the circumferential coagulation in the tubular tissues in a reliable manner.


Subject(s)
Optical Devices , Phototherapy/instrumentation , Temperature , Tracheal Stenosis/therapy , Animals , Diffusion , Lasers , Mechanical Phenomena , Rabbits
11.
Opt Lett ; 42(4): 659-662, 2017 Feb 15.
Article in English | MEDLINE | ID: mdl-28198892

ABSTRACT

Stimulated Raman scattering (SRS) microscopy that is capable of both high-speed imaging and rapid spectroscopy will be advantageous for detailed chemical analysis of heterogeneous biological specimens. We have developed a system based on spectral focusing SRS technology with the integration of a rapid scanning optical delay line, which allows continuous tuning of SRS spectra by scanning a galvo mirror. We demonstrate SRS spectral measurements of dimethyl sulfoxide solution at low concentrations and multi-color imaging of rice pollens and HeLa cells with line-by-line delay tuning to reduce motion artifacts, as well as fast acquisition of SRS spectra at specific regions of interest.


Subject(s)
Microscopy/methods , Optical Devices , Spectrum Analysis, Raman/methods , HeLa Cells , Humans , Microscopy/instrumentation , Oryza , Pollen/cytology , Spectrum Analysis, Raman/instrumentation , Time Factors
12.
J Biomed Opt ; 21(12): 127004, 2016 12 01.
Article in English | MEDLINE | ID: mdl-27992631

ABSTRACT

Microscale optical devices enabled by wireless power harvesting and telemetry facilitate manipulation and testing of localized biological environments (e.g., neural recording and stimulation, targeted delivery to cancer cells). Design of integrated microsystems utilizing optical power harvesting and telemetry will enable complex in vivo applications like actuating a single nerve, without the difficult requirement of extreme optical focusing or use of nanoparticles. Silicon-on-insulator (SOI)-based platforms provide a very powerful architecture for such miniaturized platforms as these can be used to fabricate both optoelectronic and microelectronic devices on the same substrate. Near-infrared biomedical optics can be effectively utilized for optical power harvesting to generate optimal results compared with other methods (e.g., RF and acoustic) at submillimeter size scales intended for such designs. We present design and integration techniques of optical power harvesting structures with complementary metal oxide semiconductor platforms using SOI technologies along with monolithically integrated electronics. Such platforms can become the basis of optoelectronic biomedical systems including implants and lab-on-chip systems.


Subject(s)
Metals/chemistry , Optical Devices , Optical Imaging/instrumentation , Prostheses and Implants , Semiconductors , Silicon/chemistry , Telemetry/instrumentation , Equipment Design , Humans , Oxides/chemistry , Skin/diagnostic imaging
13.
J Immunotoxicol ; 13(4): 439-48, 2016 07.
Article in English | MEDLINE | ID: mdl-27042761

ABSTRACT

Aluminum oxide nanoparticles (AlO NP) have been widely utilized in a variety of areas, including in the optical, biomedical and electronic fields and in the overall development of nanotechnologies. However, their toxicological profiles are still not fully developed. This study compared the distribution and immunotoxicity of two rod-types of AlO NP. As reported previously, the two types of AlO NP had different aspect ratios (long-type: 6.2 ± 0.6, short-type: 2.1 ± 0.4), but the size and surface charge were very similar. On Day 14 after a single intravenous (IV) injection (1.25 or 5 mg/kg), both AlO NP accumulated primarily in the liver and spleen and altered the levels of redox response-related elements. The accumulated level was higher in mice exposed to the long-type AlO NP compared to the short-type. Additionally, it was noted that the levels of IL-1ß, IL-8 and MCP-1 were enhanced in the blood of mice exposed to both types of AlO NP and the percentages of neutrophils and monocytes among all white blood cells were increased only in mice injected with the long-type AlO NP (5 mg/kg). In addition, as compared to the control, co-expression of CD80 and CD86 (necessary for antigen presentation) on splenocytes together with a decreased expression of chemotaxis-related marker (CD195) was attenuated by exposure to the AlO NP, especially the long-type. Taken together, the data suggest that accumulation following a single IV injection with rod-types of AlO NP is strengthened by a high aspect ratio and, subsequently, this accumulation has the potential to influence immune functions in an exposed host.


Subject(s)
Aluminum Oxide/pharmacokinetics , Inflammation/immunology , Liver/metabolism , Monocytes/immunology , Nanotechnology , Neutrophils/immunology , Spleen/metabolism , Aluminum Oxide/chemistry , Aluminum Oxide/immunology , Animals , Antigen Presentation , Interleukin-1beta/metabolism , Interleukin-8/metabolism , Liver/immunology , Metal Nanoparticles/chemistry , Mice , Mice, Inbred ICR , Optical Devices , Spleen/immunology
14.
Prim Care ; 42(3): 377-91, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26319344

ABSTRACT

Age-related macular degeneration (AMD) is the leading cause of vision loss in the elderly. AMD is diagnosed based on characteristic retinal findings in individuals older than 50. Early detection and treatment are critical in increasing the likelihood of retaining good and functional vision.


Subject(s)
Macular Degeneration/epidemiology , Macular Degeneration/therapy , Primary Health Care , Referral and Consultation , Aged , Aged, 80 and over , Comorbidity , Dietary Supplements , Humans , Incidence , Light Coagulation/methods , Macular Degeneration/diagnosis , Middle Aged , Optical Devices , Photochemotherapy/methods , Prevalence , Risk Factors , Vascular Endothelial Growth Factor A/antagonists & inhibitors
15.
Appl Opt ; 54(1): 123-31, 2015 Jan 01.
Article in English | MEDLINE | ID: mdl-25967014

ABSTRACT

In the laser drilling of teeth, a microplasma is generated which may be utilized for elemental analysis of ablated tissue via a laser-induced breakdown spectroscopy (LIBS) technique. In this study, LIBS is used to investigate the possibility of discrimination of healthy and carious tooth tissues. This possibility is examined using multivariate statistical analysis called partial least square discriminant analysis (PLS-DA) based on atomic and ionic emission lines of teeth LIBS spectra belonging to P, Ca, Mg, Zn, K, Sr, C, Na, H, and O elements. Results show an excellent discrimination and prediction of unknown tooth tissues. It is shown that using the PLS-DA method, the spectroscopic analysis of plasma emission during the laser drilling, would be a promising technique for caries detection.


Subject(s)
Dental Caries/diagnosis , Optical Devices , Tooth/anatomy & histology , Calcium/analysis , Discriminant Analysis , Durapatite/analysis , Equipment Design , Humans , Image Processing, Computer-Assisted , Lasers , Least-Squares Analysis , Light , Minerals/analysis , Multivariate Analysis , Phosphorus/analysis
16.
Integr Biol (Camb) ; 7(4): 477-84, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25804890

ABSTRACT

Cellular mechanical properties constitute good markers to characterize tumor cells, to study cell population heterogeneity and to highlight the effect of drug treatments. In this work, we describe the fabrication and validation of an integrated optofluidic chip capable of analyzing cellular deformability on the basis of the pressure gradient needed to push a cell through a narrow constriction. We demonstrate the ability of the chip to discriminate between tumorigenic and metastatic breast cancer cells (MCF7 and MDA-MB231) and between human melanoma cells with different metastatic potential (A375P and A375MC2). Moreover, we show that this chip allows highlighting the effect of drugs interfering with microtubule organization (paclitaxel, combretastatin A-4 and nocodazole) on cancer cells, which leads to changes in the pressure-gradient required to push cells through the constriction. Our single-cell microfluidic device for mechanical evaluation is compact and easy to use, allowing for an extensive use in different laboratory environments.


Subject(s)
Antineoplastic Agents/administration & dosage , Biological Assay/instrumentation , Flow Cytometry/instrumentation , Lab-On-A-Chip Devices , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/secondary , Apoptosis/drug effects , Cell Movement , Cell Separation/instrumentation , Drug Evaluation, Preclinical/instrumentation , Equipment Design , Equipment Failure Analysis , Flow Injection Analysis/instrumentation , Neoplasms, Experimental/pathology , Optical Devices
17.
Occup Ther Int ; 22(2): 51-60, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25367222

ABSTRACT

The objective of this study was to evaluate the effects of mirror therapy in combination with biofeedback functional electrical stimulation (BF-FES) on motor recovery of the upper extremities after stroke. Twenty-nine patients who suffered a stroke > 6 months prior participated in this study and were randomly allocated to three groups. The BF-FES + mirror therapy and FES + mirror therapy groups practiced training for 5 × 30 min sessions over a 4-week period. The control group received a conventional physical therapy program. The following clinical tools were used to assess motor recovery of the upper extremities: electrical muscle tester, electrogoniometer, dual-inclinometer, electrodynamometer, the Box and Block Test (BBT) and Jabsen Taylor Hand Function Test (JHFT), the Functional Independence Measure, the Modified Ashworth Scale, and the Stroke Specific Quality of Life (SSQOL) assessment. The BF-FES + mirror therapy group showed significant improvement in wrist extension as revealed by the Manual Muscle Test and Range of Motion (p < 0.05). The BF-FES + mirror therapy group showed significant improvement in the BBT, JTHT, and SSQOL compared with the FES + mirror therapy group and control group (p < 0.05). We found that BF-FES + mirror therapy induced motor recovery and improved quality of life. These results suggest that mirror therapy, in combination with BF-FES, is feasible and effective for motor recovery of the upper extremities after stroke.


Subject(s)
Biofeedback, Psychology , Electric Stimulation Therapy , Motor Activity/physiology , Occupational Therapy/methods , Optical Devices , Stroke Rehabilitation , Upper Extremity/physiopathology , Aged , Female , Humans , Male , Middle Aged , Pilot Projects , Quality of Life , Range of Motion, Articular , Recovery of Function , Stroke/physiopathology , Treatment Outcome
18.
Opt Express ; 22(21): 25817-29, 2014 Oct 20.
Article in English | MEDLINE | ID: mdl-25401615

ABSTRACT

We study theoretically modal properties and parametric dependence of guided-mode resonance bandpass filters operating in the mid- and near-infrared spectral domains. We investigate three different device architectures consisting of single, double, and triple layers based on all-transparent dielectric and semiconductor thin films. The three device classes show high-performance bandpass filter profiles with broad, flat low-transmission sidebands accommodating sharp transmission peaks with their efficiencies approaching 100% with appropriate blending of multiple guided modes. We present three modal coupling configurations forming complex mixtures of two or three distinct leaky modes coupling at different evanescent diffraction orders. These modal compositions produce various widths of sidebands ranging from ~30 nm to ~2100 nm and transmission peak-linewidths ranging from ~1 pm to ~10 nm. Our modal analysis demonstrates key attributes of subwavelength periodic thin-film structures in multiple-modal blending to achieve desired transmission spectra. The design principle is applicable to various optical elements such as high-power optical filters, low-noise label-free biochemical sensor templates, and high-density display pixels.


Subject(s)
Filtration/instrumentation , Optical Phenomena , Signal Processing, Computer-Assisted , Germanium/chemistry , Optical Devices , Selenium/chemistry , Signal Processing, Computer-Assisted/instrumentation , Silicon Dioxide/chemistry , Spectrum Analysis
19.
Appl Opt ; 53(28): 6527-36, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25322242

ABSTRACT

We present designs of all-optical ultrafast YES/NOT, XOR/XNOR logic gates, binary counter, and double-bit comparator based on all-optical switching by two-photon absorption induced free-carrier injection in silicon 2 × 2 add-drop microring resonators. The proposed circuits have been theoretically analyzed using time-domain coupled-mode theory based on reported experimental values to realize low power (∼ 28 mW) ultrafast (∼ 22 ps) operation with high modulation (80%) and bit rate (45 Gb/s). The designs are complementary metal-oxide semiconductor compatible and provide advantages of high Q-factor, tunability, compactness, cascadibility, scalability, reconfigurability, simplicity, and minimal number of switches and inputs for realization of the desired logic. Although a two-bit counter has been shown, the scheme can easily be extended to N-bit counter through cascading.


Subject(s)
Optical Devices , Signal Processing, Computer-Assisted/instrumentation , Silicon/chemistry , Surface Plasmon Resonance/instrumentation , Equipment Design , Equipment Failure Analysis , Miniaturization
20.
Neurology ; 83(11): 1012-7, 2014 Sep 09.
Article in English | MEDLINE | ID: mdl-25107877

ABSTRACT

OBJECTIVE: We explored the effectiveness of mirror therapy (MT) in the treatment of unilateral neglect in stroke patients. METHODS: This is an open, blinded endpoint, randomized controlled trial carried out from January 2011 to August 2013. We included stroke patients with thalamic and parietal lobe lesions with unilateral neglect 48 hours after stroke. Patients were randomized to the MT group or the control group (sham MT), and both the groups received limb activation. Patients received treatment for 1-2 hours a day 5 days a week for 4 weeks. The primary outcome was unilateral neglect assessed by a blinded assessor using the star cancellation test, the line bisection test, and a picture identification task at 1, 3, and 6 months. This study was registered at http://clinicaltrials.gov (NCT 01735877). RESULTS: Forty-eight patients were randomized to MT (n = 27) or the control group (n = 21). Improvement in scores on the star cancellation test over 6 months was greater in the MT group (mean difference 23, 95% confidence interval [CI] 19-28; p < 0.0001). Similarly, improvement in the MT group was observed in the scores on the picture identification task (mean difference 3.2, 95% CI 2.4-4.0; p < 0.0001) and line bisection test (mean difference 8.6, 95% CI 2.7-14.6; p = 0.006). CONCLUSIONS: In patients with stroke, MT is a simple treatment that improves unilateral neglect. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with neglect from thalamic and parietal lobe strokes, MT improves neglect.


Subject(s)
Optical Devices , Perceptual Disorders/etiology , Perceptual Disorders/therapy , Stroke/complications , Female , Follow-Up Studies , Hand , Humans , Male , Meta-Analysis as Topic , Middle Aged , Optical Illusions , Parietal Lobe/pathology , Perceptual Disorders/pathology , Prospective Studies , Psychomotor Performance , Severity of Illness Index , Stroke/pathology , Thalamus/pathology , Treatment Outcome
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