High-resolution Video Imaging Research Articles

Live-Animal Tracking of Individual Hematopoietic Stem Cells in Their Niche.

Stem cells reside in a specialized, regulatory environment termed “niche” that dictates how they generate, maintain, and repair tissues. We have previously documented in living animals that transplanted stem/progenitor populations (HSPC) localize to sub-domains of marrow microvessels, where CXCL12 is particularly abundant. We have now used high-resolution combined confocal and two-photon video imaging of individual hematopoietic cells in the calvarium bone marrow of living animals over time to examine the relationship of stem and progenitor cells to blood vessels, osteoblasts, and endosteal surfaces as they home and engraft. Osteoblasts were enmeshed in microvessels, and relative positioning of stem/progenitor cells within this complex tissue was non-random and dynamic. Both cell autonomous and non-autonomous factors influenced primitive cell localization. Different hematopoietic cell subsets localized to distinct locations according to the stage of differentiation. In settings of engraftment as well as expansion, marrow stem/progenitor cells were in closer proximity to bone and osteoblasts. The hematopoietic stem/progenitor cell niche is both perivascular and periendosteal in trabecular bone with physiologic demand influencing closer positioning of stem cells to bone.

Tumor necrosis factor-α: a new mechanism of ischemic ventricular fibrillation?

Tumor necrosis factor-α: a new mechanism of ischemic ventricular fibrillation?

RICE: A Reliable and Efficient Remote Instrumentation Collaboration Environment

Remote access of scientific instruments over the Internet (i.e., remote instrumentation) demand high‐resolution (2D and 3D) video image transfers with simultaneous real‐time mouse and keyboard controls. Consequently, user quality of experience (QoE) is highly sensitive to network bottlenecks. Further, improper user control while reacting to impaired video caused due to network bottlenecks could result in physical damages to the expensive instrument equipment. Hence, it is vital to understand the interplay between (a) user keyboard/mouse actions toward the instrument, and (b) corresponding network reactions for transfer of instrument video images toward the user. In this paper, we first present an analytical model for characterizing user and network interplay during remote instrumentation sessions in terms of demand and supply interplay principles of traditional economics. Next, we describe the trends of the model parameters using subjective and objective measurements obtained from QoE experiments. Thereafter, we describe our Remote Instrumentation Collaboration Environment (RICE) software that leverages our experiences from the user and network interplay studies, and has functionalities that facilitate reliable and efficient remote instrumentation such as (a) network health awareness to detect network bottleneck periods, and (b) collaboration tools for multiple participants to interact during research and training sessions.

Ultra-high-resolution monolithic thermal bubble inkjet print head

A monolithic inkjet print head, fabricated with silicon micromachining technology and capable of generating microscale liquid droplets, is developed and shown to function successfully. The print head uses a dense array of thermal bubble inkjet devices, made on a single silicon wafer. Each device is made of a Pt heater stack, a small, shallow fluid chamber, and a refilling channel formed by a Ge-sacrificial etching process, a deep-etched through-wafer feeding hole, and a micron-scale nozzle opened in a thin nitride membrane by plasma etching. Experimental results with a high resolution video imaging system show that this print head is capable of generating water droplets as small as 3 µm in diameter (0.014 pL), about 1/70th the volume of the droplets produced by existing inkjet systems. The printing process is also found to be stable, uniform in droplet size and velocity, and free of satellite droplets at optimum operation conditions. At small distances between the print head and substrate, droplet spreading is also small. This print head is then a capable tool for ultra-high-resolution inkjet printing and can be used in research areas where delivery of micron-scale fluid droplets is desired.

Double balloon endoscopy in pediatric patients

Endoscopy techniques revolutionized the diagnostic and therapeutic approaches for patients with GI diseases. The recent development of video endoscopy provides high-resolution video images and opens a new dimension in clinical gastroenterology. However, the small intestine remains the final frontier, and direct visualization of its lumen has not been satisfactory until recently. Two innovative techniques, capsule endoscopy and double balloon endoscopy (DBE), have enabled physicians to gain access to the small intestine. In the beginning of 2001, Yamamoto et al 1 Yamamoto H. Sekine Y. Sato Y. et al. Total enteroscopy with a nonsurgical steerable double-balloon method. Gastrointest Endosc. 2001; 53: 216-220 Abstract Full Text Full Text PDF PubMed Scopus (1146) Google Scholar reported the development of the double-balloon method as a new insertion technique for enteroscopy that allows observation of the entire small intestine. Subsequently, a new system of double balloon enteroscopy for the diagnosis and treatment of small intestinal disorders was reported in 2003. 2 Yamamoto H. Sugano K. A new method of enteroscopy—the double-balloon method. Can J Gastroenterol. 2003; 17: 273-274 PubMed Google Scholar

Promoting rapid learning in the histology laboratory by integrating technology

A challenging aspect for students in histology courses is to locate specific morphological structures found on glass slides using light microscopes. One-on-one instructor demonstrations can be time consuming in laboratory classes with high student enrollment. Here, I tested the teaching impact of (a) verbal instruction by the faculty combined with high-resolution video imaging (HRVI) versus (b) written descriptions alone. Questions included: which type of student (one with a one-semester histology course background or little-to-no background) would be able to find specific histological structures more rapidly, regardless of teaching method used (HRVI versus written descriptions)? and would students be able to find specific histological structures more rapidly using HRVI versus written descriptions? The results showed that students with a one-semester histology course background were able to locate more quickly specific histological structures than students who had little-to-no background. Students could locate more quickly specific histological structures using the HRVI method. This was the case regardless of their previous histological background. The data demonstrate that the use a compound light microscope connected with HRVI for instruction enhances student learning in histology courses.

Particle tracking in a salinity gradient: A method for measuring sinking rate of individual phytoplankton in the laboratory

This paper presents a new method to measure the sinking rates of individual phytoplankton “particles” (cells, chains, colonies, and aggregates) in the laboratory. Conventional particle tracking and high resolution video imaging were used to measure particle sinking rates and particle size. The stabilizing force of a very mild linear salinity gradient (1 ppt over 15 cm) prevented the formation of convection currents in the laboratory settling chamber. Whereas bulk settling methods such as SETCOL provide a single value of sinking rate for a population, this method allows the measurement of sinking rate and particle size for a large number of individual particles or phytoplankton within a population. The method has applications where sinking rates vary within a population, or where sinking rate‐size relationships are important. Preliminary data from experiments with both laboratory and field samples of marine phytoplankton are presented here to illustrate the use of the technique, its applications, and limitations. Whereas this paper deals only with sinking phytoplankton, the method is equally valid for positively buoyant species, as well as nonbiological particles.

Optical Coherence Tomography (OCT) for Diagnosis of Early Barrett's Adeno Cancer (BC) and Early Squamous Cancer (SC)

The high resolution of OCT suggests an applicability in the diagnosis and staging of early cancer. Aim: To develop OCT-criteria for early cancer (BC and SC) compared to non-neoplastic tissue (squamous epithelium, SE, and Barrett's esophagus, BE). Methods: The OCT system is a prototype and was developed in collaboration between LightLab Imaging, Westford, MA, and PENTAX Corporation, Japan. It uses flexible optical imaging probes (0.75 and 1.5 mm diameter) that emit near-infrared light. High-resolution real-time video images are created (radial scans up to 15 f/s, longitudinal reconstruction by using a standardized pull-back up to 55 mm in length, axial resolution 15 microns, lateral resolution 25 microns, penetration depth up to 2 mm). OCT was used to investigate early BC and SC prior to endoscopic mucosal resection (EMR), additional measurements were made of BE and SE. The histology of the resection specimen and biopsies of BE and SE served as controls. Results: 40 pt (31 m, 9 f, 64 +/− 11 y) with suspect of BC (n = 24) or SC (n = 16) were included. The penetration depth was 1.47 +/− 0.22 mm with no difference between BC and SC (p = ns). In 16 pt with SC all layers were clearly visible in non-neoplastic SE with 0.36 +/− 0.05 mm distance from epithelial surface (ES) to lamina propria (LP) and 0.78 +/− 0.10 mm from ES to the submucosa (SM). In the neoplastic area layers were only visible on 5 of 16 patients (p = 0.001); this was the case in 3/3 pt. with CIS, in 2/6 pt. with T1mucosa cancer and in 0/7 pt. with T1submucosa cancer. The distances from ES to LP (0.78 +/−0.13) and from ES to SM (1.12 +/− 0.17) were significantly increased in case of neoplasia (p < 0.05). In 20 of 24 pt with BE layers were visible in non-neoplastic areas with 0.61 +/− 0.14 mm distance from ES to LP and 1.04 +/− 0.17 mm from ES to SM. Only 21 pt finally proved to have BC. In the neoplastic area layers were only visible in 4 of 21 patients (p = 0.001); this was the case in 1/3 pt. with highgrade neoplasia, in 3/11 pt. with T1mucosa cancer and in 0/4 pt. with T1submucosa cancer. Measurement of penetration depth was not possible in BC because of diffuse light scattering. Conclusions: The prototype OCT system is able to scan larger regions for neoplasia and infiltration depth (in vivo, real-time, simultaneous longitudinal and radial scan). The penetration depth through tissue is acceptable for scanning mucosa and submucosa of SC. Improvements are necessary for satisfactory scanning of BC.

森林映像モニタリングデータによるマルチメディアコンテンツ製作

The multimedia contents which allow users to sense a daily, monthly and yearly change of natural environment in the Tokyo University forest in Chichibu, Japan, were produced by the forest environment monitoring video data. The authors developed three types of digital contents, namely (1) A Paper printed calendar which allows users to look at the scenery of the forest at a glance. (2) A DVD (Digital Video Disk) which provides a high-resolution forest video images with high quality environmental sounds of the forest with user-friendly operation. (3) A web site that allows users to download the PDF file of (1) to make the calendar and get the information how to obtain the DVD, and also to play a movie to see a monthly change of the forest landscape with sound. Through this production, the process of multimedia contents production was clarified and the feasibility of media mix method was examined. This kind of multimeda contents is considered user-oriented, as user can further develop the meaning and usage of it by themselves. A further study in this field will help to develop environmental learning materials with which the users can sense time changes by forest video data.

Digital video capture and synchronous consultation in open surgery.

To achieve real-time or simultaneous surgical consultation and education to students in distant locations, we report the successful integration of robotics, video-teleconferencing, and intranet transmission using currently available hardware and Internet capabilities. Accurate visualization of the surgical field with high-resolution video imaging cameras such as the closed-coupled device (CCD) of the laparoscope can serve to insure clear visual observation of surgery and share the surgical procedure with trainees and, or consultants in a distant location. Prior work has successfully applied optics and technical advances to achieve precise visualization in laparoscopy. Twenty-five thyroidectomy explorations in 15 patients were monitored and transmitted bidirectionally with audio and video data in real-time. Remotely located surgical trainees (n = 4) and medical students (n = 3) confirmed 7 different anatomic landmarks during each surgical procedure. The study used the Socrates System (Computer Motion, Inc. [CMI], Goleta, CA), an interactive telementoring system inclusive of a telestration whiteboard, in conjunction with the AESOP robotic arm and Hermes voice command system (CMI). A 10-mm flat laparoscopic telescope was used to capture the optical surgical field. As voice, telestrator, or marker confirmed each anatomic landmark the image parameters of resolution, chroma (light position and intensity), and luminance were assessed with survey responses. Confirmation of greater than 90% was achieved for the majority of relevant anatomic landmarks, which were viewed by the remote audience. The data presented in this study support the feasibility for mentoring and consultation to a remote audience with visual transmission of the surgical field, which is otherwise very difficult to share. Additionally, validation of technical protocols as teaching tools for robotic instrumentation and computer imaging of surgical fields was documented.

Comparison of aerial video and Landsat 7 data over ponded sea ice

The development of melt ponds on Arctic sea ice during spring and summer is of great importance to the Arctic climate system as it accelerates the decay of the sea ice and greatly reduces the albedo. Both melt pond development and its spatial distribution are needed to understand the surface energy balance in summer. Previously, a technique was developed for classifying summer sea ice characteristics, including the amount of open water, white (snow-covered) ice, wet ice, and melt ponds using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) spectral information. In this paper, we refine this technique through the use of airborne video data coincident with Landsat ETM+ imagery obtained over Baffin Bay on June 27, 2000. The video images, having a resolution of about 1.5 m at an aircraft altitude of 1.4 km, are classified into open water, ponded or wet ice, and unponded sea ice. Comparison of the video and Landsat imagery shows that many of the melt ponds are too small to cover an entire Landsat pixel (resolution of 30 m) so that the Landsat classification scheme would underestimate melt pond fraction. Thirteen high-resolution video images are classified to develop a method to calculate fractions of open water, ponded or wet ice, and unponded ice from Landsat 7 data. A comparison between these classified video images and Landsat retrievals yields a correlation coefficient of 0.95 with rms errors of less than 9% for the two ice types and 2% for open water. Comparisons of Landsat and video analyses not used in the development of the algorithm yield correlation coefficients of 0.87 for open water, 0.68 for ponded ice, and 0.78 for unponded ice. The rms differences are 10%, 8%, and 11%, respectively.

Rotational high-resolution video image display

Rotational high-resolution video image display

An overview of the intuitive system: The surgeon's perspective

An overview of the intuitive system: The surgeon's perspective

Understanding conduction of electrical impulses in the mouse heart using high-resolution video imaging technology.

The conduction of electrical impulses in the heart depends on the ability to efficiently transfer excitatory current between individual myocytes. Several recent studies have focused on the use of optical mapping techniques to determine the electrophysiological consequences and the proarrhythmic effects of reducing intercellular coupling in newly developed connexin knockout mice. This work has begun to unravel important questions regarding the role of connexins in intercellular coupling and propagation of electrical impulses in the heart. The purpose of this review is to discuss the techniques and unique issues involved in imaging electrical wave propagation in the heart. In addition, we will review recent experimental studies that address the role of intercellular communication in the development of cardiac arrhythmias.

Dynamics of wavelets and their role in atrial fibrillation in the isolated sheep heart.

The multiple wavelet hypothesis is the most commonly accepted mechanism underlying atrial fibrillation (AF). However, high frequency periodic activity has recently been suggested to underlie atrial fibrillation in the isolated sheep heart. We hypothesized that in this model, multiple wavelets during AF are generated by fibrillatory conduction away from periodic sources and by themselves may not be essential for AF maintenance. We have used a new method of phase mapping that enables identification of phase singularities (PSs), which flank individual wavelets during sustained AF. The approach enabled characterization of the initiation, termination, and lifespan of wavelets formed as a result of wavebreaks, which are created by the interaction of wave fronts with functional and anatomical obstacles in their path. AF was induced in six Langendorff-perfused sheep hearts in the presence of acetylcholine. High resolution video imaging was utilized in the presence of a voltage sensitive dye; two-dimensional phase maps were constructed from optical recordings. The major results were as follows: (1) the critical inter-PS/wavelet distance for the formation of rotors was 4 mm, (2) the spatial distribution of wavelets/PSs was non-random. (3) the lifespan of PSs/wavelets was short; 98% of PSs/wavelets existed for < 1 rotation, and (4) the mean number of waves that entered our mapping field (15.7 +/- 1.6) exceeded the mean number of waves that exited it (9.7 +/- 1.5; P < 0.001). Our results strongly suggest that multiple wavelets may result from breakup of high frequency organized waves in the isolated Langendorff-perfused sheep heart, and as such are not a robust mechanism for the maintenance of AF in our model.

A mechanism of transition from ventricular fibrillation to tachycardia : effect of calcium channel blockade on the dynamics of rotating waves.

Abbreviation of the action potential duration and/or effective refractory period (ERP) is thought to decrease the cycle length of reentrant arrhythmias. Verapamil, however, paradoxically converts ventricular fibrillation (VF) to ventricular tachycardia (VT), despite reducing the ERP. This mechanism remains unclear. We hypothesize that the size and the dynamics of the core of rotating waves, in addition to the ERP, influence the arrhythmia manifestation (ie, VF or VT). The objectives of this study were (1) to demonstrate functional reentry as a mechanism of VF and VT in the isolated Langendorff-perfused rabbit heart in the absence of an electromechanical uncoupler and (2) to elucidate the mechanism of verapamil-induced conversion of VF to VT. We used high-resolution video imaging with a fluorescent dye, ECG, frequency and 2-dimensional phase analysis, and computer simulations. Activation patterns in 10 hearts were studied during control, verapamil perfusion (2x10(-6) mol/L), and washout. The dominant frequency of VF decreased from 16.2+/-0.7 to 13.5+/-0.6 Hz at 20 minutes of verapamil perfusion (P<0.007). Concomitantly, phase analysis revealed that wavefront fragmentation was reduced, as demonstrated by a 3-fold reduction in the density of phase singularities (PSs) on the ventricular epicardial surface (PS density: control, 1.04+/-0.12 PSs/cm(2); verapamil, 0.32+/-0.06 PSs/cm(2) [P=0.0008]). On washout, the dominant frequency and the PS density increased, and the arrhythmia reverted to VF. The core area of transiently appearing rotors significantly increased during verapamil perfusion (control, 4.5+/-0.6 mm(2); verapamil, 9.2+/-0.5 mm(2) [P=0.0002]). In computer simulations, blockade of slow inward current also caused an increase in the core size. Rotating waves underlie VF and VT in the isolated rabbit heart. Verapamil-induced VF-to-VT conversion is most likely due to a reduction in the frequency of rotors and a decrease in wavefront fragmentation that lessens fibrillatory propagation away from the rotor.

High-frequency periodic sources underlie ventricular fibrillation in the isolated rabbit heart.

The mechanism(s) underlying ventricular fibrillation (VF) remain unclear. We hypothesized that at least some forms of VF are not random and that high-frequency periodic sources of activity manifest themselves as spatiotemporal periodicities, which drive VF. Twenty-four VF episodes from 8 Langendorff-perfused rabbit hearts were studied using high-resolution video imaging in conjunction with ECG recordings and spectral analysis. Sequential wavefronts that activated the ventricles in a spatially and temporally periodic fashion were identified. In addition, we analyzed the lifespan and dynamics of wavelets in VF, using a new method of phase mapping that enables identification of phase singularity points (PSs), which flank individual wavelets. Spatiotemporal periodicity was found in 21 of 24 episodes. Complete reentry on the epicardial surface was observed in 3 of 24 episodes. The cycle length of discrete regions of spatiotemporal periodicity correlated highly with the dominant frequency of the optical pseudo-ECG (R(2)=0.75) and with the global bipolar electrogram (R(2)=0.79). The lifespan of PSs was short (14.7+/-14.4 ms); 98% of PSs existed for <1 rotation. The mean number of waves entering (6.50+/-0.69) exceeded the mean number of waves that exited our mapping field (4.25+/-0.56; P<0.05). These results strongly suggest that ongoing stable sources are responsible for the majority of the frequency content of VF and therefore play a role in its maintenance. In this model, multiple wavelets resulting from wavebreaks do not appear to be responsible for the sustenance of this arrhythmia, but are rather the consequence of breakup of high-frequency activation from a dominant reentrant source.

地学における先端テクノロジー 深海調査技術 有人潜水調査船と無人探査機

The development of deep sea research systems-manned and unmanned submersibles-made it possible to carry out visual surveys of the deep seafloor at any depth on the earth. These surveys have revealed a great number of phenomena that occur on the seafloor, such as hydrothermal vents and chemosynthetic biological communities at mid-oceanic ridges.Unmanned submersibles include ROV (Remotely Operated Vehicle), UROV (Untethered Remotely Operated Vehicle), which have thrusters and are operated by mother ship through a tether cable or a thin optical fiber respectively, AUV (Autonomous Underwater Vehicle) which moves under pre-programmed commands and does not have a cable, and deep-tow system which is also operated by mother ship through. a cable but does not have a thruster.In order to see objects under very low illumination in deep seas, a Super-HARP (High-gain Avalanche Rushing Amorphous Photoconductor) video camera which is far more sensitive than CCD cameras, was developed. Recently, the Super HARP Hi-vision video camera, which provides high-resolution video images, has been developed.The location of the submersible in water is obtained by three acoustic positioning systems. These are called LBL (Long Base Line), SBL (Short Base Line), and SSBL (Super Short Base Line) positioning systems.In order to achieve effective dive surveys by manned submersibles or ROVs, it is necessary to select dive points by considering the results of pre-surveys carried out over a wide area, including bathymetric mapping using multi-narrow beam echo sounder, side-scan sonar survey, and deep-towed camera surveys.Submersibles enable not only visual observation, but also sampling and geophysical measurement at aimed points on the deep seafloor. In order to construct multi-disciplinary real-time and long-term deep seafloor observatories, such as off Hatsushima Island Observatory and VENUS off Okinawa Island Observatory, or to carry out borehole measurements, submersibles have been playing important roles in installing instruments, extending cables, and connecting connectors of instruments to underwater telemetry systems, or in recovering data. Submersibles are also necessary when searching for the causes of events observed by the observatory.The ROV and the Super HARP Hi-vision video camera made it possible for many scientists on board to see high-resolution video images of the seafloor simultaneously as if they were viewing it with the unaided eye. The AUV will enable surveys over wide areas in the near future. However, observations by submersibles are limited by survey time. On the other hand, long-term observatories enable observations only at fixed points. Complimentary observations using both long-term observatories and submersibles are expected in order to extend survey area in terms of both temporality and spatiality to provide an understanding of phenomena that occur on the seafloor.

New immunodiagnostic system

We have developed a new immunodiagnostic system whichmeasures personal allergen exposure and which can beused to identify allergens.Personal exposure is directly sampled using inertialimpaction filters which fit just inside the nose andcollect particles (mainly >5 µm) inhaled duringnormal respiration. These samplers provide both anindex of personal exposure as well as being aninexpensive and portable sampling system.The particles are captured on adhesive tapes which arethen laminated with a protein-binding membrane. Theallergens eluting from the particles are bound by the membrane in theperiphery of each particle. The systemthen uses either allergen-specific monoclonalantibodies or the subject's IgE as primary probes toimmuno-label the `halo' of allergen around individualallergen-containing particles. Such an assay is verysensitive and can detect a single particle carryingallergens. In addition, the system providesinformation on the size, shape and allergen content ofthe particles. Because the particles carryingallergens can be seen, high resolution video images ofpollen grains and fungal spores can be subjected to atraditional morphological study or a range of featureextraction routines. This information can be comparedto a database of some known allergenic pollen grainsand fungal spores which we have also assembled tofacilitate their identification. When using monoclonal antibodies as the probe, thesystem determines the amount of allergen the subjectis exposed to and the characteristics of the particles(size, shape, etc). When using the subject's IgE as theprobe, the system allows visualisation of the allergensources that an individual is allergic to. The systemmay have clinical applications in quantifying personalexposure as well as identifying allergens anddetermining exposure to unsuspected allergens.

SuperENC: MPEG-2 video encoder chip

Thanks to increased market acceptance of applications such as digital versatile disks (DVDs), HDTV, and digital satellite broadcasting, the MPEG-2 (Moving Picture Experts Group-2) standard is becoming widely used. The MPEG-2 video standard, established in 1934, provides for a high-quality video compression format that, through high bit rates and frame rates, yields high-resolution video images. Emerging multimedia applications, such as digital versatile disk and high-definition television, demand higher quality video than ever before. In response, our MPEG-2 video encoder chip supports multiple profiles and levels.