Charge-coupled Device Camera System Research Articles

Shape from Shading-Based Study of Silica Fusion Characterization Problems

With the rapid development of AI (artificial intelligence) in recent years, AI has been widely used in the image processing of iron tailings. The main component of iron tailings is silica, which is the most difficult part of the iron tailing composition to fuse. Therefore, the melting behavior of iron tailings can be characterized by the melting behavior of silica. First of all, in the actual production process, the temperature of the high-temperature furnace exceeds 1500 °C, which leads to a short service life of the conventional testing equipment. A line array CCD (charge coupled device) camera system with amplification effect was used to acquire data on silica in a high-temperature melt pool in a non-contact manner. The corundum crucible position is fixed, which can be used to establish a two-dimensional coordinate system to reproduce the object’s motion pattern to solve the problem of the short service life of conventional inspection equipment. The color and wobble problems generated by the Rift Valley CCD system when taking pictures need to be corrected for accurate image processing. Secondly, the change in the center-of-mass position of silica during melting was studied using the temporal images of silica in a high-temperature melt pool, and the edge contour features were extracted from the silica images and filled inside the contours, from which the mass, area and perimeter were obtained. Finally, the volume change of silica in the time series image is calculated after eliminating the effect of background factors, and the 2D image is constructed into a 3D image. We built a SFS (shape from shading) model according to the lighting conditions, and the actual melting rate of silica is calculated accordingly. According to the model calculation results, it can be seen that with the change in time, silica surface area under heat gradually decreases, then the silica melting rate gradually decreases; among them, the faster melting rate is about 0.007 cubic millimeter/second, and the slower melting rate is about 0.0015 cubic millimeter/second. Data support was provided for the blast furnace slag direct fiber formation process. The introduction of the algorithmic model into the actual production process has certain advantages. Therefore, the SFS model established in this paper has some practical value and is worth promoting in related enterprises.

Mechanical properties of 1670 MPa parallel wire strands at elevated temperatures

High-strength prestressing steel cables serve as main load-bearing components for cable-supported structures, and exposure to high temperatures may result in their prestress loss, leading to failure and even collapse of such structures. This paper experimentally investigates the mechanical properties of 7-wire parallel wire strands with a tensile strength of 1670 MPa. The thermal elongation tests and steady-state tensile tests are conducted on 39 strand specimens at different target temperatures. The complete stress-strain curves including rupture strain are obtained by using charge-coupled device camera systems. The temperature-dependent thermal strain, Young’s modulus, proportional limit, effective yield strength, ultimate strength, ultimate strain and rupture strain are recorded and compared to EC2, ACI 216 and other existing test data. The test results show that parallel wire strands experience obvious strain hardening before 300 °C, and their ductility is significantly improved after 400 °C. It is reasonable to define effective yield strength as the stress at a total strain of 2%. It is found that the existing design code and test data on single wires and twisted strands cannot be directly used for parallel strands. The EC2 provides conservative predictions for ultimate strain, proportional limit, yield strength of parallel wire strands, but fails to capture the full range of stress-strain curves of parallel strands due to ignoring strain hardening effect and underestimating rupture strain. The ACI 216 provides unconservative predictions for reduction factors of ultimate strength of parallel strands. Parallel wire strands have higher thermal strain, higher ultimate strain, higher rupture strain, lower reduction factor of proportional limit than single wires and twisted wire strands. Finally, calculation methods are proposed to mathematically determine the thermal strain, stress-strain curve and reduction factors of these properties, and dividing the stress-strain relationship into elastic, plastic, necking and rupture stage.

Parametric Dependence of Type-I and Type-III ELMs and Dynamic Characteristics for ELM Filaments in EAST Tokamak

A simple and effective classification method to distinguish type-I and type-III edge-localized modes (ELMs) in an experimental advanced superconducting tokamak is introduced and some key parameters affecting the type-I and type-III ELMy H-modes are analyzed. The results indicate that the heating power and the edge safety factor q95 have strong correlations with the appearance of type-I and type-III ELMs. By using the high-speed visible-light charge-coupled device camera system, the dynamic characteristics of ELM filaments are studied and the features of type-I and type-III ELM filaments have been compared. The radial outward velocity for type-I ELMy filaments can be up to 1.5-3.5 km/s while for type-III ELMs one is about 0.5-2 km/s. In the process of type-I and type-III ELMy filaments outward propagation, the width of filament decreases gradually, while the velocity of filament increases. In addition, during an ELM event, it can be observed that the earlier the burst of an ELM filament, the higher the radial velocity it will have.

Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

BackgroundSpectral domain optical coherence tomography (SD-OCT) was a useful tool to study accommodation in human eye, but the maximum image depth is limited due to the decreased signal-to-noise ratio (SNR). In this study, improving optical resolutions, speeds and the SNR were achieved by custom built SD-OCT, and the evaluation of the impact of the improvement during accommodation was investigated.MethodsThree systems with different spectrometer designs, including two Charge Coupled Device (CCD) cameras and one Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera, were tested. We measured the point spread functions of a mirror at different positions to obtain the axial resolution and the SNR of three OCT systems powered with a light source with a 50 nm bandwidth, centered at a wavelength of 840 nm. Two normal subjects, aged 26 and 47, respectively, and one 75-year-old patient with an intraocular lens implanted were imaged.ResultsThe results indicated that spectrometers using cameras with 4096 camera pixels optimized the axial resolutions, due to the use of the full spectrum provided by the light source. The CCD camera system with 4096 pixels had the highest SNR and the best image quality. The system with the CMOS camera with 4096 pixels had the highest speed but had a compromised SNR compared to the CCD camera with 4096 pixels.ConclusionsUsing these three OCT systems, we imaged the anterior segment of the human eye before and after accommodation, which showed similar results among the different systems. The system using the CMOS camera with an ultra-long scan depth, high resolution and high scan speed exhibited the best overall performance and therefore was recommended for imaging real-time accommodation.

Microstructured boron foil scintillating G-GEM detector for neutron imaging

In this study, a new simple neutron imaging gaseous detector was successfully developed by combining a micro-structured 10B foil, a glass gas electron multiplier (G-GEM), and a mirror–lens–charge-coupled device (CCD)–camera system. The neutron imaging system consists of a chamber filled with Ar/CF4 scintillating gas mixture. Inside this system, the G-GEM is mounted for gas multiplication. The neutron detection in this system is based on the reaction between 10B and neutrons. A micro-structured 10B is developed to overcome the issue of low detection efficiency. Secondary electrons excite Ar/CF4 gas molecules, and high-yield visible photons are emitted from those excited gas molecules during the gas electron multiplication process in the G-GEM holes. These photons are easily detected by a mirror–lens–CCD–camera system. A neutron radiograph is then simply formed. We obtain the neutron images of different materials with a compact accelerator-driven neutron source. We confirm that the new scintillating G-GEM-based neutron imager works properly with low gamma ray sensitivity and exhibits a good performance as a new simple digital neutron imaging device.

Technical Note: Range verification system using edge detection method for a scintillator and a CCD camera system.

Three-dimensional irradiation with a scanned carbon-ion beam has been performed from 2011 at the authors' facility. The authors have developed the rotating-gantry equipped with the scanning irradiation system. The number of combinations of beam properties to measure for the commissioning is more than 7200, i.e., 201 energy steps, 3 intensities, and 12 gantry angles. To compress the commissioning time, quick and simple range verification system is required. In this work, the authors develop a quick range verification system using scintillator and charge-coupled device (CCD) camera and estimate the accuracy of the range verification. A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The optical spatial resolution of the system is 0.2 mm/pixel. The camera control system was connected and communicates with the measurement system that is part of the scanning system. The range was determined by image processing. Reference range for each energy beam was determined by a difference of Gaussian (DOG) method and the 80% of distal dose of the depth-dose distribution that were measured by a large parallel-plate ionization chamber. The authors compared a threshold method and a DOG method. The authors found that the edge detection method (i.e., the DOG method) is best for the range detection. The accuracy of range detection using this system is within 0.2 mm, and the reproducibility of the same energy measurement is within 0.1 mm without setup error. The results of this study demonstrate that the authors' range check system is capable of quick and easy range verification with sufficient accuracy.

Navigation surgery for intraoperative sentinel lymph node detection using Indocyanine green (ICG) fluorescence real-time imaging in breast cancer

A new sensitive fluorescence imaging system was developed for the real-time identification of sentinel lymph nodes (SLNs) in patients with early breast cancer. The purpose of this study was to evaluate the utility of a color charge-coupled device camera system for the intraoperative detection of SLNs and to determine its clinical efficacy and sensitivity in patients with operable breast cancer. We assessed a total of 168 patients diagnosed with or suspected of having early-stage breast cancer without metastasis in SLNs. The intraoperative detection of SLNs was performed using the conventional Indigo Carmine dye (indigotindisulfonate sodium) technique combined with a new Indocyanine green (ICG) imaging system (HyperEye Medical System: HEMS, MIZUHO IKAKOGYO, Japan) to map SLNs, in which the lymphatic vessels and SLNs were visualized transcutaneously with illuminating ICG fluorescence. Between January 2012 and May 2013, SLNs were successfully identified in all 168 patients (detection rate: 100%). By histopathology, the sensitivity was 93.8% for the detection of the metastatic involvement of SLNs (15 of 16 nodal-positive patients). After a median follow-up of 30.5 months, none of the patients presented with axillary recurrence. These results suggest that the HEMS imaging system is a feasible and effective method for the detection of SLNs in breast cancer. Furthermore, the HEMS device permitted the transcutaneous visualization of lymphatic vessels under light conditions, thus facilitating the identification and detection of SLNs without affecting the surgical procedure, together with a high sensitivity and specificity.

The Developments and Achievements of Endoscopic Surgery, Robotic Surgery and Function-preserving Surgery

The breakthrough in laparoscopic surgery has been the development of a charge-coupled device camera system and Mouret performing cholecystectomy in 1987. The short-term benefits of laparoscopic surgery are widely accepted and the long-term benefit of less incidence of bowel obstruction can be expected. The important developments have been the articulating instrumentation via new laparoscopic access ports. Since 2007, single-incision laparoscopic surgery has spread all over the world. Not only single-scar but also no-scar operation is a current topic. In 2004, Kalloo reported the flexible transgastric peritoneoscopy as a novel approach to therapeutic interventions. In 2007, Marescaux reported transvaginal cholecystectomy in a patient. The breakthrough in robotic surgery was the development of the da Vinci Surgical System. It was introduced to Keio University Hospital in March 2000. Precision in the surgery will reach a higher level with the use of robotics. In collaboration with the faculty of technology and science, Keio University, the combined master-slave manipulator has been developed. The haptic forceps, which measure the elasticity of organs, have also been developed. The first possible sites of lymphatic metastasis are known as sentinel nodes. Otani reported vagus-sparing segmental gastrectomy under sentinel node navigation. This kind of function-preserving surgery will be performed frequently if the results of the multicenter prospective trial of the dual tracer method are favorable. Indocyanine green fluorescence-guided method using the HyperEye charge-coupled device camera system can be a highly sensitive method without using the radioactive colloid. 'Minimally invasive, function-preserving and precise surgery under sentinel node navigation in community hospital' may be a goal for us.

New device for intraoperative graft assessment: HyperEye charge-coupled device camera system

Our institution developed a new color chargecoupled device (CCD) camera system (HyperEye system) for intraoperative indocyanine green (ICG) angiography. The device consists of a combination of custommade optical filters and an ultra-high-sensitive CCD image sensor with non-Bayer color filter array (i.e., HyperEye technology), which can detect simultaneously color and near-infrared (NIR) rays from 380 to 1200 nm. Here, we demonstrate intraoperative graft assessment using the HyperEye system. We investigated the intraoperative graft patency using both the HyperEye system and transittime flowmetry (TFM) in 51 patients between April 2007 and April 2009 while ICG dye was injected through a central venous catheter. Each patient signed a consent form before the surgery. We obtained intraoperative graft flows and images in 189 anastomoses of 153 grafts. Both the HyperEye system and TFM indicated the patency of the grafts in 129 grafts. Both the HyperEye system and TFM detected the abnormality of the graft in seven grafts. For the competitive flows, the HyperEye system captured to-and-fro flow fluorescence and TFM detected the retrograde waveform in 16 grafts. On the other hand, although TFM indicated the patency of the graft, the HyperEye system suspected nonoccluded graft failure in seven grafts. In contrast, although TFM detected a mean flow of <10 ml/min, the HyperEye system captured the patent perfusion fluorescence in four grafts. The HyperEye system can visualize any structural and functional failures. Our findings suggest that this device could become a useful tool for intraoperative graft assessment.

Activation of the Unfolded Protein Response in Wound Healing

Introduction: The unfolded protein response (UPR) is an adaptive response centered in the endoplasmic reticulum (ER) to protect cells against the accumulation of misfolded proteins due to increased cellular stresses or protein synthesis. Activation of the UPR triggers cell signaling through three pathways: IRE1-XBP1, PERK-ATF4, and ATF6. Dysregulation of the UPR has been implicated in diseases as diverse as type I diabetes mellitus and cancer. We have previously demonstrated increased UPR activation in keloid-derived fibroblasts. We wished to examine the normal activation of the UPR in wound healing and its potential role. Methods: A construct was generated containing a luciferase (Luc) gene driven by XBP1 enhancer sites (XBP1-Luc). XBP1-Luc was transfected into the HT1080 pancreatic adenocarcinoma cell line to confirm responsiveness of the construct to UPR activation. Transfected cells were subjected to hypoxia (<0.1% O2) or ER stress conditions (tunicamycin, no glucose). Transgenic mice were generated with the construct and subjected to excisional skin wounding. In vivo imaging was performed using an IVIS charge-coupled device camera system (Xenogen, Alameda, CA). Results: XBP1-Luc reporter activity in HT1080 cells was strongly induced after 16-24 h of incubation in hypoxic conditions (<0.1% O2) or ER stress conditions, known UPR inducers, and reflected endogenous XBP1 activation. Furthermore, reporter activity decayed to near-background levels within 24 hours after reoxygenation, indicating that cellular luminescence reflects recent or ongoing ER stress. Following excisional wounding, we began seeing an initial increase in XBP1-Luc signal in the transgenic animals 8-10 days after wounding with nearly 10-fold increased activity seen at day 14. Conclusions: The UPR has been demonstrated to be an important pathway in a variety of pathologies. This represents the first description of UPR activation in wound healing. By defining the temporal and spatial activation of the UPR during wound healing, we hope it will provide insights into its biological role. We have already identified enhanced activation of the UPR in keloid cells compared to normal cells suggesting that modulation of the UPR can offer a new approach to wound healing therapies.

Identification of KCNJ15 as a Susceptibility Gene in Asian Patients with Type 2 Diabetes Mellitus

Recent advances in genome research have enabled the identification of new genomic variations that are associated with type 2 diabetes mellitus (T2DM). Via fine mapping of SNPs in a candidate region of chromosome 21q, the current study identifies potassium inwardly-rectifying channel, subfamily J, member 15 (KCNJ15) as a new T2DM susceptibility gene. KCNJ15 is expressed in the beta cell of the pancreas, and a synonymous SNP, rs3746876, in exon 4 (C566T) of this gene, with T allele frequency among control subjects of 3.1%, showed a significant association with T2DM affecting lean individuals in three independent Japanese sample sets (p = 2.5 x 10(-7), odds ratio [OR] = 2.54, 95% confidence interval [CI] = 1.76-3.67) and with unstratified T2DM (p = 6.7 x 10(-6), OR = 1.76, 95% CI = 1.37-2.25). The diabetes risk allele frequency was, however, very low among Europeans in whom no association between this variant and T2DM could be shown. Functional analysis in human embryonic kidney 293 cells demonstrated that the risk allele of the synonymous SNP in exon 4 increased KCNJ15 expression via increased mRNA stability, which resulted in the higher expression of protein as compared to that of the nonrisk allele. We also showed that KCNJ15 is expressed in human pancreatic beta cells. In conclusion, we demonstrated a significant association between a synonymous variant in KCNJ15 and T2DM in lean Japanese patients with T2DM, suggesting that KCNJ15 is a previously unreported susceptibility gene for T2DM among Asians.

Preliminary experience for the evaluation of the intraoperative graft patency with real color charge-coupled device camera system: an advanced device for simultaneous capturing of color and near-infrared images during coronary artery bypass graft☆

We developed a new color charge-coupled device (CCD) camera for the intraoperative indocyanine green (ICG) angiography. This device consists of a combination of custom-made optical filters and an ultra-high sensitive CCD image sensor, which can detect simultaneously color and near-infrared (NIR) rays from 380 to 1200 nm. We showed a comparison between our system and other devices for the preliminary experience. We routinely performed both transit-time flowmetry (TFM) and color images for intraoperative assessment, thallium-scintigraphy for the early postoperative assessment, and then angiography after 1-year surgery. We also obtained intraoperative graft flows and images in 116 grafts. Although TFM indicated a graft patency, the CCD camera suspected perfusion failures in four grafts. Also the analysis of the ICG fluorescence intensity showed the significant hypoperfusion at the perfusion territory distal to the anastomosis (graft vs. perfusion territory; 230+/-26 vs. 156+/-13 a.u, P=0.02). When the CCD camera suspected a graft failure, CCD camera and angiography showed a comparable graft failure. The unique device that visualized ICG-enhanced structures against a background of natural myocardial color improved the visibility of abnormality in flow and perfusion. Our findings show that this device may become a standard intraoperative graft and perfusion assessment tool in coronary artery bypass graft (CABG).

Development of X-ray CCD camera system with high readout rate using ASIC

We report on the development of an X-ray charge-coupled device (CCD) camera system with high readout rate using application-specific integrated circuit (ASIC) and Camera Link standard. The distinctive Δ Σ type analog-to-digital converter is introduced into the chip to achieve effective noise shaping and to obtain a high resolution with relatively simple circuits. The unit test proved moderately low equivalent input noise of 70 μ V with a high readout pixel rate of 625 kHz, while the entire chip consumes only 100 mW. The Camera Link standard was applied for the connectivity between the camera system and frame grabbers. In the initial test of the whole system, we adopted a P-channel CCD with a thick depletion layer developed for X-ray CCD camera onboard the next Japanese X-ray astronomical satellite. The characteristic X-rays from 109Cd were successfully read out resulting in the energy resolution of 379 ( ± 7 ) eV (FWHM) @22.1 keV, that is, Δ E / E = 1.7 % with a readout rate of 44 kHz.

The Cytoplasmic Tail Dileucine Motif LL572 Determines the Glycosylation Pattern of Membrane-type 1 Matrix Metalloproteinase

Membrane-type 1 matrix metalloproteinase (MT1-MMP; MMP-14) drives fundamental physiological and pathological processes, due to its ability to process a broad spectrum of substrates. Because subtle changes in its activity can produce profound physiological effects, MT1-MMP is tightly regulated. Currently, many aspects of this regulation remain to be elucidated. It has recently been discovered that O-linked glycosylation defines the substrate spectrum of MT1-MMP. We hypothesized that a mutual interdependency exists between MT1-MMP trafficking and glycosylation. Lectin precipitation, metabolic labeling, enzymatic deglycosylation, and site-directed mutagenesis studies demonstrate that the LL(572) motif in the cytoplasmic tail of MT1-MMP influences the composition of the complex O-linked carbohydrates attached to the hinge region of the protein. This influence appears to be independent from major effects on cell surface trafficking. MT1-MMP undergoes extensive processing after its synthesis. The origins and the molecular characters of its multiple forms are incompletely understood. Here, we develop and present a model for the sequential, post-translational processing of MT1-MMP that defines stages in the post-synthetic pathway pursued by the protein.

Effets cardioprotecteurs du propofol dans des cœurs ischémiques puis reperfusés isolés chez le cobaye: rôle des canaux KATP et du GSK GSK-3β

Propofol exerts cardioprotective effects, but the involved mechanisms remain obscure. The present study examines the cardioprotective effects of propofol and its role in cardiac function, including its effect on K(ATP) channel opening and the inhibition of GSK-3beta activity in ischemia-reperfused hearts. Ischemia-reperfusion (I/R) was produced in isolated guinea pig hearts by stopping coronary perfusion for 25 min, followed by reperfusion. The hearts were incubated for ten minutes, with or without propofol (25 or 50 microM), or for five minutes with 500 microM 5-hydroxydecanoate (a mitochondrial K(ATP) channel blocker) or 30 microM HMR1098 (sarcolemmal K(ATP) channel blocker), followed by five minutes with 50 microM propofol before ischemia. Action potentials on the anterior epicardial surface of the ventricle were monitored using a high-resolution charge-coupled device camera system, and at five minutes after reperfusion, GSK-3beta phosphorylation at the serine residue, Ser9, was examined. After 35 min of reperfusion, propofol (25 and 50 microM) blunted the adverse effects of I/R and reduced infarct size (P < 0.05). In addition, prior incubation with 5-hydroxydecanoate or HMR1098 had no effect on functional recovery improved by 50 microM propofol. At five minutes after reperfusion, propofol (25 and 50 microM) shortened the duration of the action potential and increased the levels of phospho-GSK-3beta (P < 0.05). Propofol enhanced mechanical cardiac recovery and reduced infarct size. The data further suggest that GSK-3beta play an important role in propofol cardioprotective actions during coronary reperfusion, but mitochondrial K(ATP) channels do not.

A charge coupled device camera with electron decelerator for intermediate voltage electron microscopy

Electron microscopists are increasingly turning to intermediate voltage electron microscopes (IVEMs) operating at 300-400 kV for a wide range of studies. They are also increasingly taking advantage of slow-scan charge coupled device (CCD) cameras, which have become widely used on electron microscopes. Under some conditions, CCDs provide an improvement in data quality over photographic film, as well as the many advantages of direct digital readout. However, CCD performance is seriously degraded on IVEMs compared to the more conventional 100 kV microscopes. In order to increase the efficiency and quality of data recording on IVEMs, we have developed a CCD camera system in which the electrons are decelerated to below 100 kV before impacting the camera, resulting in greatly improved performance in both signal quality and resolution compared to other CCDs used in electron microscopy. These improvements will allow high-quality image and diffraction data to be collected directly with the CCD, enabling improvements in data collection for applications including high-resolution electron crystallography, single particle reconstruction of protein structures, tomographic studies of cell ultrastructure, and remote microscope operation. This approach will enable us to use even larger format CCD chips that are being developed with smaller pixels.

Modulation of Yeast Sln1 Kinase Activity by the Ccw12 Cell Wall Protein

The yeast Sln1p sensor kinase is best known as an osmosensor involved in the regulation of the hyperosmolarity glycerol mitogen-activated protein kinase cascade. Down-regulation of Sln1 kinase activity occurs under hypertonic conditions and leads to phosphorylation of the Hog1p mitogen-activated protein kinase and increased osmotic stress-response gene expression. Conditions leading to kinase up-regulation include osmotic imbalance caused by glycerol retention in the glycerol channel mutant, fps1 (Tao, W., Deschenes, R. J., and Fassler, J. S. (1999) J. Biol. Chem. 274, 360-367). The hypothesis that Sln1p kinase activity is responsive to turgor was first suggested by the increased Sln1p kinase activity in mutants lacking Fps1p in which glycerol accumulation leads to water uptake. Also consistent with the turgor hypothesis is the observation that reduced turgor caused by treatment of cells with nystatin, a drug that increases membrane permeability and causes cell shrinkage, reduced Sln1p kinase activity (Tao, W., Deschenes, R. J., and Fassler, J. S. (1999) J. Biol. Chem. 274, 360-367; Reiser, V., Raitt, D. C., and Saito, H. (2003) J. Cell Biol. 161, 1035-1040). The turgor hypothesis is revisited here in the context of the identification and characterization of the cell wall gene, CCW12, as a determinant of Sln1p activity. Results of this analysis suggest that the activity of the plasma membrane localized Sln1p is affected by the presence or absence of specific outer cell wall proteins and that this effect is independent of turgor.

Detailed Performance Analysis of a 10kW Dish∕Stirling System

The CNRS-Promes dish∕Stirling system was erected in Jun. 2004 as the last of three country reference units built in the “Envirodish” project. It represents the latest development step of the EuroDish system with many improved components. With a measured peak of 11kW electrical output power, it is also the best performing system so far. The measurement campaign to determine the optical and thermodynamic efficiency of the system is presented. The optical quality of the concentrator and the energy input to the power conversion unit was measured with a classical flux-mapping system using a Lambertian target and a charge coupled device camera system. An efficiency of the concentrator including the intercept losses of 74.4% could be defined for this particular system. For the thermodynamic analysis all the data necessary for a complete energy balance around the Stirling engine were measured or approximated by calculations. For the given ambient conditions during the tests, a Stirling engine efficiency of 39.4% could be measured. The overall efficiency for the conversion of solar to electric energy was 22.5%.

Applications of direct detection device in transmission electron microscopy

A prototype direct detection device (DDD) camera system has shown great promise in improving both the spatial resolution and the signal to noise ratio for electron microscopy at 120-400 keV beam energies (Xuong et al., 2007. Methods in Cell Biology, 79, 721-739). Without the need for a resolution-limiting scintillation screen as in the charge coupled device (CCD), the DDD camera can outperform CCD based systems in terms of spatial resolution, due to its small pixel size (5 microm). In this paper, the modulation transfer function (MTF) of the DDD prototype is measured and compared with the specifications of commercial scientific CCD camera systems. Combining the fast speed of the DDD with image mosaic techniques, fast wide-area imaging is now possible. In this paper, the first large area mosaic image and the first tomography dataset from the DDD camera are presented, along with an image processing algorithm to correct the specimen drift utilizing the fast readout of the DDD system.

Sensitivity and Depth Penetration of Continuous Wave Versus Frequency-domain Photon Migration Near-infrared Fluorescence Contrast-enhanced Imaging ¶

The development of near-infrared fluorescent contrast agents and imaging techniques depends on the deep penetration of excitation light through several centimeters of tissue and the sensitive collection of the re-emitted fluorescence. In this contribution, the sensitivity and depth penetration of various fluorescence-enhanced imaging studies is surveyed and compared with current studies using continuous wave (CW) and frequency-domain photon migration (FDPM) measurements with planar wave illumination of modulated excitation light at 100 MHz and area collection of reemitted fluorescent light using a previously developed modulated intensified charge-coupled device camera system. Fluorescence was generated from nanomolar to micromolar solutions of indocyanine green (ICG) in a 100 μL volume submerged at 1–4 cm depths in a 1% Liposyn® solution to mimic tissue scattering properties. Enhanced depth penetration and sensitivity are achieved with optimal filter rejection of excitation light, and FDPM rejection of background light is not achieved using CW methods. We show the ability to detect as few as 100 fmol of ICG from area illumination of 785 nm light (5.5 mW/cm2) and FDPM area collection of 830 nm fluorescent light generated from 3 cm below the phantom surface. The lowered noise floor of FDPM measurements enables greater sensitivity and penetration depth than comparable CW measurements.