Permanent Markers Research Articles

APPLICATION ACCURACY OF COMPUTED TOMOGRAPHY-BASED, IMAGE-GUIDED NAVIGATION OF TEMPORAL BONE

Although frameless stereotactic techniques have become indispensable in neurosurgery, their technical complexity requires careful definition and evaluation. Navigation is of particular concern when it is applied to approach a complex, tight surgical area like the temporal bone, where every millimeter is important. Theoretically, the temporal bone is an ideal location in which to use image-guided navigation because its bony construct precludes pre- and intraoperative shift. In this context, the feasibility of using a navigational system is determined by the system's accuracy and by the spatial characteristics of the targets. Literature addressing the accuracy of image guidance techniques in temporal bone surgery is relatively sparse. Accuracy of these systems within the temporal bone is still under investigation. We investigated the application accuracy of computed tomography-based, frameless, image-guided navigation to identify various bony structures in the temporal bone via a retrosigmoid approach. In a total of 10 operations, we performed a retrosigmoid approach simulating operative conditions on either side of 5 whole, fresh cadaveric heads. Six titanium microscrews were implanted around the planned craniotomy site as permanent bone reference markers before the surgical procedure. High-resolution computed tomographic scans were obtained (slice thickness, 0.6-mm, contiguous non-overlapping slices; gantry setting, 0 degrees; scan window diameter, 225 mm; pixel size, >0.44 x 0.44). We used a Stryker navigation system (Stryker Instruments, Kalamazoo, MI) for intraoperative navigation. External and internal targets were selected for calculation of navigation accuracy. The system calculated target registration error to be 0.48 +/- 0.21 mm, and the global accuracies (navigation accuracies) were calculated using external over-the-skull and internal targets within the temporal bone. Overall navigation accuracy was 0.91 +/- 0.28 mm; for reaching internal targets within temporal bone, accuracy was 0.94 +/- 0.22 mm; and for external targets, accuracy was 0.83 +/- 0.11 mm. Ninety-five percent of targets could be reached within 1.4 mm of their actual position. Using high-resolution computed tomography and bone-implanted reference markers, frameless navigation can be as accurate as frame-based stereotaxy in providing a guide to maximize safe surgical approaches to the temporal bone. Although error-free navigation is not possible with the submillimetric accuracy required by direct anatomic contouring of tiny structures within temporal bone, it still provides a road map to maximize safe surgical exposure.

Cell lineage in mammalian craniofacial mesenchyme

We have analysed the contributions of neural crest and mesoderm to mammalian craniofacial mesenchyme and its derivatives by cell lineage tracing experiments in mouse embryos, using the permanent genetic markers Wnt1-cre for neural crest and Mesp1-cre for mesoderm, combined with the Rosa26 reporter. At the end of neural crest cell migration (E9.5) the two patterns are reciprocal, with a mutual boundary just posterior to the eye. Mesodermal cells expressing endothelial markers (angioblasts) are found not to respect this boundary; they are associated with the migrating neural crest from the 5-somite stage, and by E9.5 they form a pre-endothelial meshwork throughout the cranial mesenchyme. Mesodermal cells of the myogenic lineage also migrate with neural crest cells, as the branchial arches form. By E17.5 the neural crest-mesoderm boundary in the subectodermal mesenchyme becomes out of register with that of the underlying skeletogenic layer, which is between the frontal and parietal bones. At E13.5 the primordia of these bones lie basolateral to the brain, extending towards the vertex of the skull during the following 4–5 days. We used DiI labelling of the bone primordia in ex-utero E13.5 embryos to distinguish between two possibilities for the origin of the frontal and parietal bones: (1) recruitment from adjacent connective tissue or (2) proliferation of the original primordia. The results clearly demonstrated that the bone primordia extend vertically by intrinsic growth, without detectable recruitment of adjacent mesenchymal cells.

Inhalant use among incarcerated adolescents in the United States: Prevalence, characteristics, and correlates of use

Objective To characterize patterns and correlates of inhalant use among incarcerated youth. Method Residents ( N = 723) of 27 Missouri Division of Youth Services facilities completed interviews assessing substance use, psychiatric symptoms, antisocial traits, trauma, suicidality, and criminality. Results Participants averaged 15.5 (S.D. = 1.2) years of age, were ethnically diverse, and predominantly male. More than one-third (36.9%) reported lifetime inhalant use; 47.9% of users had tried four or more inhalant products. Comparatively high rates of use were observed for Hispanic and small town/rural youth. Commonly abused agents included gasoline (22%), permanent markers (15%), computer “air duster,” (15%) and spray paint (12%). Inhalant users evidenced significantly higher levels of criminal behavior, antisocial attitudes, current psychiatric symptoms, earlier onset of offending and substance use, and more extensive histories of head injury, kidney disease, hormonal problems, mental illness, suicidality, trauma, and substance-related problems than nonusers. In multiple logistic regression models, race/ethnicity, geographic area of residence, fearlessness, suicidality, and polydrug use distinguished inhalant users and nonusers. Measures of cognitive impairment, impulsivity, fearlessness, blame externalization, polydrug use, and substance-related problems were positively associated with lifetime frequency of inhalant use. Conclusions Inhalant use was widespread in this sample and associated with serious physical and mental health impairments.

Forensic Applications of Infrared Imaging for the Detection and Recording of Latent Evidence

We report on a simple method to record infrared (IR) reflected images in a forensic science context. Light sources using ultraviolet light have been used previously in the detection of latent prints, but the use of infrared light has been subjected to less investigation. IR light sources were used to search for latent evidence and the images were captured by either video or using a digital camera with a CCD array sensitive to IR wavelength. Bloodstains invisible to the eye, inks, tire prints, gunshot residue, and charred document on dark background are selected as typical matters that may be identified during a forensic investigation. All the evidence types could be detected and identified using a range of photographic techniques. In this study, a one in eight times dilution of blood could be detected on 10 different samples of black cloth. When using 81 black writing inks, the observation rates were 95%, 88% and 42% for permanent markers, fountain pens and ball-point pens, respectively, on the three kinds of dark cloth. The black particles of gunshot residue scattering around the entrance hole under IR light were still observed at a distance of 60 cm from three different shooting ranges. A requirement of IR reflectivity is that there is a contrast between the latent evidence and the background. In the absence of this contrast no latent image will be detected, which is similar to all light sources. The use of a video camera allows the recording of images either at a scene or in the laboratory. This report highlights and demonstrates the robustness of IR to detect and record the presence of latent evidence.

Methodology for the Re-location of Permanent Plot Markers Using Spatial Analysis

Abstract A well-designed method of establishing, maintaining, and remeasuring permanent plots plays an essential role in long-term data collection. This article describes the re-location of plots set up 25 years earlier using conventional techniques of paced distances and compass directions. As a result, we needed to design and use a method for re-locating plot markers originally established without the benefit of spatial coordinates. Preplanned ground searches using a GIS, digital orthophotoquads, landmark maps, and aerial photographs improved our plot location efficiency and success. In 2003, we were able to re-locate 90% of the plots set up in 1978 to measure the vegetation dynamics after a fire in Baxter State Park, Maine. The spatial coordinates of these permanent plots were documented for future measurement. Lessons learned and techniques developed for this project can facilitate the re-location of permanent plots in other studies and can also be used to improve the documentation of newly established plot locations.

The lymphoid past of mouse plasmacytoid cells and thymic dendritic cells.

There has been controversy over the possible lymphoid origin of certain dendritic cell (DC) subtypes. To resolve this issue, DC and plasmacytoid pre-DC isolated from normal mouse tissues were analyzed for transient (mRNA) and permanent (DNA rearrangement) markers of early stages of lymphoid development. About 27% of the DNA of CD8(+) DC from thymus, and 22-35% of the DNA of plasmacytoid pre-DC from spleen and thymus, was found to contain IgH gene D-J rearrangements, compared with 40% for T cells. However, the DC DNA did not contain IgH gene V-D-J rearrangements nor T cell Ag receptor beta gene D-J rearrangements. The same DC lineage populations containing IgH D-J rearrangements expressed mRNA for CD3 chains, and for pre-T alpha. In contrast, little of the DNA of the conventional DC derived from spleen, lymph nodes, or skin, whether CD8(+) or CD8(-), contained IgH D-J rearrangements and splenic conventional DC expressed very little CD3 epsilon or pre-T alpha mRNA. Therefore, many plasmacytoid pre-DC and thymic CD8(+) DC have shared early steps of development with the lymphoid lineages, and differ in origin from conventional peripheral DC.

Improving the precision of longitudinal ecological surveys using precisely defined observational units

AbstractIn ecological longitudinal studies, it is difficult to precisely define an observational unit. In many cases the investigator must decide between permanent observational units or observational units with no permanent markers (re‐established each year). The latter choice is appealing as there are no maintenance costs, but the loss of precision in a longitudinal study can be severe. In this article, we analytically demonstrate that by not permanently and precisely marking observational units in a longitudinal study, the efficiency can be reduced, or the cost increased, or both. The magnitude of loss is illustrated for a coral reef benthic survey where precision was reduced by as much as a factor of 12. General formulae to estimate the relative efficiency of ecological surveys based on different levels of observational unit markings are also presented. Copyright © 2003 John Wiley & Sons, Ltd.

Geometric morphometric differences between Panstrongylus geniculatus from field and laboratory

The finding of Panstrongylus geniculatus nymphs inside a house in northeastern Antioquia, Colombia, and the reports related to their increasing presence in homes suggest the need for surveillance methods for monitoring the invasion processes. We analyzed the morphological differences between a wild population and its laboratory descendants, using the techniques of geometric morphometry, with the idea that such differences might parallel those between sylvatic and synanthropic populations. The analyses over five generations showed differences in size but not in shape. Head size and wing size were both reduced from sylvatic to laboratory populations, but the decrease in head size occurred only up to the second generation while the decrease in wing size proceeded up to the fifth generation. In contrast, although a decrease in sexual size dimorphism has been proposed as a marker of colonization in human dwellings, we did not detect any significant loss of dimorphism between sexes of P. geniculatus over the five generations studied. We conclude that size changes may have a physiological origin in response to a change of ecotopes, but more than five generations may be required for the expression of permanent morphological markers of human dwellings colonization.

Minor neurological signs and developmental performance in high risk children at preschool age.

The aim of this study was to establish correlations between minor neurological findings and developmental performance. A cohort of 72 preschool children was studied (38 females, 34 males; mean age 3 years 8 months, SD 1 year 2 months, range 2 to 5 years) who were considered to be at high risk due to placental insufficiency. The cohort was divided into four categories of neurological status: (1) minimal cerebral palsy (MCP) with independent walking before age 2 years; (2) Amiel-Tison triad (ATT) including imbalance of passive axial tone, phasic stretch reflex in triceps surae, and cranial signs, particularly on the squamous suture; (3) intermediate with one or two of the three ATT signs; and (4) absence of neurological findings. Six subscales of the Griffiths Mental Developmental Scales assessing locomotion, eye-hand coordination, interpersonal skills, language, performance, and practical reasoning were administered. Significant differences were found according to neurological status in three specific domains of development: coordination (F=2.84, p=0.04), language (F=3.65, p=0.02), and practical reasoning (F=3.62, p=0.02). In addition, significant differences were also found in language (L) and practical reasoning (R) performances according to the side of the abnormal stretch reflex: bilateral stretches (L=87.8; R=75.3) or an isolated right stretch (L=95.3; R=83.6) are more strongly associated with impaired developmental performances than an isolated left stretch (L=101.3; R=88.2) with F=2.94; p=0.04 for language and F=3.00, p=0.04 for practical reasoning. We concluded that a short neurological examination, easily performed by pediatricians and family practitioners, can identify permanent markers of minor brain damage occurring before, during, or soon after birth and so anticipate consequences.

Minor neurological signs and developmental performance in high risk children at preschool age

The aim of this study was to establish correlations between minor neurological findings and developmental performance. A cohort of 72 preschool children was studied (38 females, 34 males; mean age 3 years 8 months, SD 1 year 2 months, range 2 to 5 years) who were considered to be at high risk due to placental insufficiency. The cohort was divided into four categories of neurological status: (1) minimal cerebral palsy (MCP) with independent walking before age 2 years; (2) Amiel‐Tison triad (ATT) including imbalance of passive axial tone, phasic stretch reflex in triceps surae, and cranial signs, particularly on the squamous suture; (3) intermediate with one or two of the three ATT signs; and (4) absence of neurological findings. Six subscales of the Griffiths Mental Developmental Scales assessing locomotion, eye‐hand coordination, interpersonal skills, language, performance, and practical reasoning were administered. Significant differences were found according to neurological status in three specific domains of development: coordination (F=2.84,p=0.04), language (F=3.65,p=0.02), and practical reasoning (F=3.62, p=0.02). In addition, significant differences were also found in language (L) and practical reasoning (R) performances according to the side of the abnormal stretch reflex: bilateral stretches (L=87.8; R=75.3) or an isolated right stretch (L=95.3; R=83.6) are more strongly associated with impaired developmental performances than an isolated left stretch (L=101.3; R=88.2) with F=2.94;p=0.04 for language and F=3.00,p=0.04 for practical reasoning. We concluded that a short neurological examination, easily performed by pediatricians and family practitioners, can identify permanent markers of minor brain damage occurring before, during, or soon after birth and so anticipate consequences.

Geochemical cycling of redox-sensitive metals in sediments from lake malawi: a diagnostic paleotracer for episodic changes in mixing depth

Changes in heat balance, wind stress, and lake level can affect the efficiency of mixing and depth of oxygen penetration in deep tropical lakes. This study examines how transient changes in these parameters, as reflected by the redox state of bottom waters, are recorded in the sedimentary record of Lake Malawi. We measured concentration profiles of redox-sensitive metals across a layer of oxidized sediment deposited within a sequence composed of reduced sediments in a core taken at 298 m water depth, ∼100 m below the present-day chemocline. By examining a range of metals that exhibit different geochemical behaviors—mobilization under reducing (Fe, Mn) versus. oxidizing (U) conditions; formation of insoluble sulfides (Cd, Mo, Pb, Zn); susceptibility to scavenging onto Fe or Mn oxyhydroxide precipitates (Co, Mo, Pb, V, Zn)—we are able to outline a sequence of events consistent with the formation of this feature: (1) At some time before 11 ky BP there was an episode of penetration of oxygenated waters to depths close to or greater than that of this core, i.e., substantially deeper in the lake basin than at present. At this time diagenetically remobilized Fe and Mn were oxidized and precipitated in a near-surface sediment horizon. (2) Fe and Mn oxyhydroxides that precipitated from the water column as metal-rich anoxic waters were mixed upward into oxygenated waters, were deposited in an immediately overlying layer of the sediment. Such material continued to accumulate in surface sediments for a few hundred years until oxic conditions no longer prevailed in overlying waters. (3) As the depth of the chemocline rose (relative to the present-day lake surface) this authigenic material was, in turn, overlain by reducing sediments. (4) Subsequent diagenetic remobilization at the top and bottom of this “redox sandwich” resulted in formation of horizons enriched in, U, Mo, and sulfide-forming metals (notably Cd) along the redox gradients both above and, to a lesser extent, below the layer of oxidized sediment. These enrichments, immobilized under reducing conditions, will remain as permanent markers of the episode of deepening of the chemocline even after reduction and remobilization of the oxidized Fe and Mn solids. In addition, such markers may be useful in determining whether observed episodic interruptions in deposition of varved sediments in the deep anoxic basins of Lake Malawi are due to bioturbation brought on by episodes of deeper oxygen penetration in the water column.

Bringing Culture Back In: Exploring the Cultural Dimensions of Disaster

This special issue is devoted to the popular culture of disaster. In virtually every type of society, human settlement patterns produce some kind of disaster, and every culture that lives through a major disaster produces some kind of cultural representation of it. The stories of a culture's experience with disaster are often passed on through folklore, remembered through permanent or occasional memorials, relived through dramatized portrayals, and embedded in a group's collective conscience as permanent markers of social time. In some societies, such as the United States, disasters occupy a central place in popular culture, appearing almost nightly on pseudo-scientific television programs and generating millions of dollars for movie makers. Because disasters and representations of them pervade so much of social life, we think it is important and worthwhile to begin paying systematic attention to the cultural dimensions of disasters. This special issue of the journal is an important step in that direction. We have tried to assemble papers that stimulate thought about various aspects of the popular culture of disaster-how it should be defined, what concepts should be used to study it, and why it is important to study. In no way is this single issue meant to be a definitive statement on the topic. In fact, if it is successful, this issue will raise more questions than it answers. By devoting an entire issue of the journal to this topic, we hope that scholars will build on what is presented here and begin thinking about alternative ways to approach the subject.

Modelling T-cell memory by genetic marking of memory T cells in vivo.

Immunological memory is the ability of the immune system to respond with enhanced vigour to pathogens that have been encountered in the past. Following infection or immunization, most effector T cells undergo apoptotic cell death, but a small fraction of these cells, proportional to the early antigen load and initial clonal burst size, persist in the host as a stable pool of memory T cells. The existence of immunological memory has been recognized for over 2,000 years, but our understanding of this phenomenon is limited, primarily because memory lymphocytes cannot be unequivocally identified as they lack specific, permanent markers. Here we have developed a transgenic mouse model system whereby memory T cells and their precursors can be irreversibly marked with a reporter gene and thus can be unambiguously identified. Adoptive transfer of marked CD8+ T cells specific for lymphocytic choriomeningitis virus protected naive recipients following viral challenge, demonstrating that we have marked memory T cells. We also show that cytotoxic effector lymphocytes that develop into memory T cells can be identified in the primary response.

SPATIAL VARIATION IN SPOIL AND VEGETATIVE CHARACTERISTICS OF PASTURES ON RECLAIMED SURFACE MINED LAND

Kentucky has large areas of reclaimed surface mined land that could provide grazing for livestock. Research is needed to determine optimal stocking densities and to evaluate the sustainability of such grazing systems for this region. A long-term grazing study was initiated in 1997 on 151 ha of reclaimed land near Chavies, KY to determine spatial and temporal variation with stocking densities of 0, 0.28, 0.42, or 0.83 beef cow-calf units/ha. Global Positioning System and GIS technologies were used to establish pasture boundaries, locate permanent sampling markers at a density of 1 per 0.4 ha, and interpolate maps of physical, spoil, and vegetable pasture characteristics. Herbage and spoil samples were collected around the permanent markers in May of 1997. Stepwise regression was used to determine factors affecting the vegetative characteristics of the sites. Biomass density ranged from 0 to 2500 kg/ha with a mean of 570 kg/ha. Factors affecting biomass included legume and weed proportions in the sward, grazing activity, soil potassium, elevation, and potential acidity, cumulatively accounting for 32% of the variation. Ground cover ranged from 10 to 100% with an average of 74%. Soil pH, potassium, and grass in the sward accounted for 14% of the variation in groundmore » cover. Legumes made up 0 to 61% of the sward with a mean of 13% over the pasture area. Variables affecting the amount of legume in the sward included biomass density, slope, elevation, pH, and stocking density, together accounting for 21% of the variation. Spatial variation in the physical, spoil, and vegetative characteristics of the pastures was large. Overall, regression accounted for a limited amount of the variation in the vegetative characteristics of the site indicating that other important variables exist.« less

Evaluating the Stability of Commercially Available Artists’ Coloring Materials Used to Create Compensation Infills for Losses in Textiles

When there is a loss in a textile, the response is to prepare a suitable structural support. Current connoisseurship trends may require the support to be more cosmetically integrated than did the aesthetics of a decade ago. Coloring agents, such as permanent inks, hand-applied dyes, fabric paints, and markers, and methods such as hand-painting and color photocopying are now being explored as alternatives to an overall dyed patch. These present immediate results and greater artistic choice, and they allow for precise control. This study attempts to determine some appropriate coloring materials. Initially 29 materials were chosen and subjectively evaluated for their aesthetic qualities based on criteria needed when recreating printed or overall dyed infills. A printed infill requires fine-line reproduction with no feathering. An overall dyed patch requires even coverage without stiffness and smooth texture without thickness. Of the 29 original materials, the 10 that possessed the characteristics needed for both drawing and coverage were then examined to determine their stability and aging characteristics. Bleed resistance, wash-fastness, absence of acidic off-gassing, crocking resistance, and lightfastness were evaluated. No material proved resistant in all testing. The results of this study can be used to select, from those materials tested, the best colorant for a particular conservation treatment.

An ultrasonic approach to localization of fiducial markers for interactive, image-guided neurosurgery--Part I: Principles.

Fiducial markers are reference points used in the registration of image space(s) with physical (patient) space. As applied to interactive, image-guided surgery, the registration of image space with physical space allows the current location of a surgical tool to be indicated on a computer display of patient-specific preoperative images. This intrasurgical guidance information is particularly valuable in surgery within the brain, where visual feedback is limited. The accuracy of the mapping between physical and image space depends upon the accuracy with which the fiducial markers were located in each coordinate system. To effect accurate space registration for interactive, image-guided neurosurgery, the use of permanent fiducial markers implanted into the surface of the skull is proposed in this paper. These small cylindrical markers are composed of materials that make them visible in the image sets. The challenge lies in locating the subcutaneous markers in physical space. This paper presents an ultrasonic technique for transcutaneously detecting the location of these markers. The technique incorporates an algorithm based on detection of characteristic properties of the reflected A-mode ultrasonic waveform. The results demonstrate that ultrasound is an appropriate technique for accurate transcutaneous marker localization. The companion paper to this article describes an automatic, enhanced implementation of the marker-localization theory described in this article.

SPATIAL AND TEMPORAL VARIATION IN MINED LAND PASTURES

Kentucky has large areas of reclaimed surface mined land that could provide grazing for livestock. Research is needed to define optimum stocking densities and to determine the sustainability of such grazing systems for this region. A long-term field study was initiated in 1997 on 151 ha of reclaimed land near Chavies, KY to assess spatial and temporal variation under grazing with stocking densities of 0, 0.28, 0.42, or 0.83 beef cow/calf pairs/ha. Global Positioning System and GIS technologies were employed to interpolate surface maps of the site using 11,000 points. Herbage and soil samples were collected around permanent markers systematically placed over the entire area at a density of 1 per 0.4 ha. Elevation ranged from 295 to 371 m and pasture slope ranged from 0 to 57{degree} with a mean of 13{degree}. Biomass density in late April ranged from 0 to 2500 kg/ha and was lowest at the highest stocking density, where grazing activity was highest. Spring-born calves averaged 240 kg at weaning. Cow weight and body condition score at the end of the grazing season was reduced at the highest stocking density and suggests that the highest stocking density may be excessive for mined land pastures in thismore » region.« less

Landscape Permanence and Nuclear Warnings

From the perspective of a human lifetime, the hazards of some nuclear wastes are permanent, so the warnings we place at contaminated nuclear sites must be permanent too. I address questions of how best to provide one hundred centuries of public warning at the first facility for permanent disposal, the Waste Isolation Pilot Plant in New Mexico. Scenarios of intrusion developed to guide the design of warning markers predicted that most of the changes in the area will be social and cultural. Because blatant and permanent markers will increase, not reduce, the probability of inadvertent intrusion, the most appropriate warning is a “landscape of illusion.” Such a landscape needs not permanent surface markers but underground warning devices beneath a soft surface marker. No warning can guarantee deterrence for 10,000 years, however.

Development of the sympathoadrenal system in the chick embryo: An immunocytochemical study with antibodies to pan-neuroendocrine markers, catecholamine-synthesizing enzymes, proprotein-processing enzymes, and neuropeptides

The adrenal chromaffin cells synthesize, store and secrete a complex mixture containing amines, structural proteins, enzymes, and neurohormonal polypeptides. Most of the studies dealing with the development of the avian sympathoadrenal system have been based on antibodies recognizing signal molecules like HNK-1, NC-1, and N-CAM. The development of the chick sympathoadrenal system was studied from 3 1/2 to 21 days of incubation, both morphologically and immunocytochemically, using antibodies to 17 separate antigens, including antibodies to pan-neuroendocrine markers, catecholamine synthesizing enzymes, proprotein-processing enzymes, and neuropeptides. Some of the antigens studied were heavily expressed from the first days of development, e.g., chromogranin-A, chromogranin-B, Go protein-alpha subunit, tyrosine hydroxylase, and galanin, while for others a strong heterogeneity both in number of immunoreactive cells and intensity of immunostaining was recorded at the different stages, e.g., dopamine-beta-hydroxylase,, 7B2 protein, proprotein convertase 2, somatostatin, met-enkephalin, secretogranin II, proprotein convertase 3, neuropeptide Y, phenyl-N-methyl transferase, and neuron-specific enolase. The first immunoreactivities to appear at day 3 1/2 were those for HNK-1, tyrosine hydroxylase, chromogranin-A, and chromogranin-B. Except for HNK-1, immunoreactivity for all the remaining antigens showed a steady increase up to the hatching. Three expression patterns were found, in the developmental adrenal-gland: defining early permanent markers (chromogranin-A, chromogranin-B, Go protein-alpha subunit, tyrosine hydroxylase, and galanin), others that show a progressively increased expression until the day 10 of development (dopamine-beta-hydroxylase, 7B2 protein, proprotein convertase 2, somatostatin, met-enkephalin), and late-appearing antigens (secretogranin II, proprotein convertase 3, neuropeptide Y, phenyl-N-methyl transferase, and neuron-specific enolase).

Water Pressure Measurement with Time Domain Reflectometry Cables

Abstract Attributes of the remote measurement of piezometric water pressure and water level with time domain reflectometry (TDR) techniques are investigated. The evaluation includes a two-wire system for unusually small riser tubes as well as parallel wire and air-filled or hollow coaxial cable for typical installations. Comparison of TDR cable and commercial pressure transducer technology shows coaxial cable TDR systems with distance crimps capable of equaling and exceeding the resolution of pressure transducers. Crimps provide permanent distance markers that allow the TDR system to be self-calibrating.