bluuebunny/crossref_metadata_2025 huggingface dataset:
Approaching the End of Life: Attitudes, Preferences, and Behaviors of African-American and White Patients and Their Family Caregivers
Authors: Phipps Etienne , True Gala , Harris Diana , Chong Umi , Tester William , Chavin Stephen I. , Braitman Leonard E.
Published: January 2003

Purpose: To investigate differences in attitudes, preferences, and behaviors regarding end of life in terminally ill patients and their designated family caregivers.

Patients and Methods: 68 African-American and white patients with stage III-B or IV lung or stage IV colon cancer and 68 patient-designated family caregivers interviewed between December 1999 and May 2001.

Results: White patients were more likely to have a durable power of attorney (34% v 8%, P = .01) and were more likely to have a living will (LW; 41% v 11%, P = .004) than were African-American patients. More African-American than white patients desired the use of life-sustaining measures (cardiopulmonary resusitation [CPR], mechanical ventilation, tube feeding) in their current condition (all P > .12). In a near-death condition, African-American patients were more likely than white patients to desire each of the life-sustaining measures (all P < .004). There was no patient-caregiver agreement beyond chance regarding preferences for initiation of CPR, tube feeding, or mechanical ventilation in the patient’s current condition or in the near-death condition. In the near-death condition in patients without LWs, there was disagreement in 46% of patient-caregiver pairs about CPR, in 50% about mechanical ventilation, and in 43% about tube feeding.

Conclusion: Although most patients and families endorse the primacy of the patient in decisions at end of life, the majority do not take supporting actions. Disagreements between patients and families about the use of life-sustaining measures in patients without LWs may result in patients’ preferences being superseded at end of life.
The effect of non‐uniform radiative damping on the zonal‐mean dynamics of the extratropical middle atmosphere
Authors: Semeniuk K. , Shepherd T. G.
Published: January 2003

The effect of spatial and temporal variations in the radiative damping rate on the response to an imposed forcing or diabatic heating is examined in a zonal‐mean model of the middle atmosphere. Attention is restricted to the extratropics, where a linear approach is viable. It is found that regions with weak radiative damping rates are more sensitive in terms of temperature to the remote influence of the diabatic circulation. The delay in the response in such regions can mean that ‘downward’ control is not achieved on seasonal time‐scales. A seasonal variation in the radiative damping rate modulates the evolution of the response and leaves a transient‐like signature in the annual mean temperature field.

Several idealized examples are considered, motivated by topical questions. It is found that wave drag outside the polar vortex can significantly affect the temperatures in its interior, so that high‐latitude, high‐altitude gravity‐wave drag is not the only mechanism for warming the southern hemisphere polar vortex. Diabatic mass transport through the 100 hPa surface is found to lag the seasonal evolution of the wave drag that drives the transport, and thus cannot be considered to be in the downward control regime. On the other hand, the seasonal variation of the radiative damping rate is found to make only a weak contribution to the annual mean temperature increase that has been observed above the ozone hole. Copyright © 2002 Royal Meteorological Society.
Multi‐model multi‐analysis ensembles in quasi‐operational medium‐range forecasting
Authors: Mylne Kenneth R. , Evans Ruth E. , Clark Robin T.
Published: January 2003

Ensemble prediction systems (EPS) for medium‐range forecasting attempt to account for uncertainty in numerical weather prediction (NWP) by sampling the distribution function of future atmospheric states. Forecast uncertainty derives from uncertainty in both the analysed initial conditions (analysis errors) and in the forecast evolution (model errors). Current operational systems are primarily based on sampling the analysis errors through initial‐condition perturbations with, at best, only limited sampling of model errors. One approach to sampling model errors and also to widening the sampling of analysis errors, is to include more than one NWP model, and more than one operational analysis to which perturbations are added, in the ensemble system. Previous work has demonstrated from a small number of case‐studies that this multi‐model multi‐analysis ensemble (MMAE) approach can perform significantly better than a single‐model system such as the Ensemble Prediction System (EPS) run by the ECMWF (European Centre for Medium‐Range Weather Forecasts). In this study a MMAE was created by combining the ECMWF ensemble with an ensemble using the Met Office model and analysis, and was run daily for a year to assess the benefits over a larger, quasi‐operational sample of forecasts. The results are compared with the operational ECMWF EPS which includes the latest upgrades, including stochastic physics which makes some allowance for uncertainty due to model errors. Results show that both for probabilistic forecasts (assessed by Brier skill scores and relative operating characteristics) and for deterministic forecasts based on the ensemble mean (assessed by root‐mean square errors) the MMAE has increased forecast skill relative to the EPS. These improvements are obtained with no overall increase in ensemble size. Ensemble spread is also greater in the MMAE, and the increased skill is believed to be due to the additional model producing solutions which are synoptically more different than those produced by a single model ensemble. Benefits of the MMAE vary both in time and with geographical region, depending on which individual ensemble system performs better in particular synoptic situations. It is found that the MMAE almost always performs as well as the best individual ensemble, and on occasions better than either of them. © Crown copyright, 2002.
Grid‐point response to the incremental strategy for variational applications
Authors: Tanguay Monique , Laroche Stéphane
Published: January 2003

The incremental approach is an efficient way to reduce the computational cost of four‐dimensional variational assimilation. In this approach, the discrepancy between the forecast fields and the observations is calculated with a full physics model at high resolution, but the minimization is performed at a lower resolution with a simplified physics model. The incremental approach is also used in sensitivity‐analysis applications where errors in the initial conditions are estimated a posteriori by replacing observations by a subsequent analysis. The incremental strategy as used in typical sensitivity analyses with observations corresponding to a full model state is re‐examined in the context of a grid‐point model by establishing how the grid‐transfer operations in grid‐point space influence the convergence properties of the whole incremental process. We show that two incremental grid‐point formulations are possible. In the first formulation, the tangent‐linear perturbations are interpolated at high resolution to be compared with the forecast errors. In the second one, the forecast errors are interpolated to low resolution before the minimization. Using a one‐dimensional study and identical twin experiments in three dimensions, we study the impact of aliasing associated with the grid‐transfer operations on the two incremental formulations. They are both affected by the misinterpretation of unresolved forecast errors leading to a contribution to resolved forecast errors. However, the first formulation has the property of damping this aliasing contribution and this effect is stronger with higher‐order grid‐transfer operators. Copyright © 2002 Royal Meteorological Society.
Research on the Dynamic Characteristics and Seismic Response of Space Frames
Authors: Zhang Yigang , Lan Tien T.
Published: January 2003

Research findings on dynamic characteristics and seismic response of space frames are introduced in this paper. It has been found that the response of space frames due to the vertical component of earthquake is larger than that due to the horizontal component of earthquake. The theoretical and practical methods for calculating forces in the members of space frame due to vertical earthquake, which is used in Chinese code of space frame, are introduced.
Physical, mechanical, and viscoelastic properties of natural rubber vulcanizates cured with new binary accelerator system
Authors: Aprem Abi Santhosh , Joseph Kuruvilla , Laxminarayanan R. , Thomas Sabu
Published: January 2003

Natural rubber was vulcanized with a new binary accelerator system based on 1‐phenyl‐2,4‐dithiobiuret (DTB) and dicyclohexyl benzothiazyl sulfenamide. A significant reduction in cure time was observed with the addition of DTB. The cure kinetics was investigated and the activation energy was determined. The mechanical properties were improved by adding DTB, and the maximum values are shown at an optimum concentration. Estimates of the concentration of crosslinks and of the relative proportions of different types of crosslinks were made by the chemical characterization of the vulcanizates. The crosslink densities obtained from swelling measurements and stress–strain measurements were compared with those obtained from modulus measurements. All of them follow a similar trend and support the observed mechanical properties. A dynamic mechanical analysis of the mixes was carried out and the activation energy was determined from Arrhenius plots. The glass‐transition temperature was found to increase with the increase in crosslink density and frequency of measurements. The stress–strain curves were found to not deviate from the strain crystallizing nature of natural rubber. The mechanical properties, network characterization, and processing characteristics were used to optimize the DTB concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2193–2203, 2003
A polyampholyte triblock copolymer synthesized for using as the surfactant of miniemulsion polymerization and production of highly uniform microspheres
Authors: Ou Jinn‐Luh , Lim Min‐Shyan , Chen Hui
Published: January 2003

Miniemulsions based on styrene/azobisisobutyronitrile (AIBN) in the presence of polyampholyte triblock copolymers as a surfactant and hexadecane (HD) as a cosurfactant were developed. The polyampholyte was prepared by using methyl methacrylate (MMA), methacrylic acid (MAA), and 2‐(dimethylamino) ethyl methacrylate (DMAEMA) as monomers. For the sake of comparison, a miniemulsion polymerization with sodium dodecyl sulfate (SDS) was carried out using the same procedure as the above series. The monomer droplet sizes and their shelf life tests revealed that the polyampholyte could stabilize miniemulsion and lead nucleation mechanisms to droplet nucleation. Miniemulsion polymerization using SDS as the surfactant possess a higher polymerization rate than that of polyampholyte, probably due to the smaller droplet size. Production of uniform microspheres was also carried out in this work. Highly uniform microspheres prepared using polyampholyte as the surfactant in the presence of acetone could be obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2230–2237, 2003
Autohesive properties of polyolefins photografted with hydrophilic monomers
Authors: Yamada Kazunori , Kimura Jun , Hirata Mitsuo
Published: January 2003

In an attempt to provide polyolefins such as low‐ and high‐density polyethylene and polypropylene with autohesive properties, hydrophilic monomers such as methacrylic acid (MAA), acrylic acid (AA), and 2‐(dimethylamino)ethyl methacrylate (DMAEMA) were photografted onto their surfaces. The wettabilities of the grafted plates stayed constant above full coverage of the substrate surfaces with grafted polymer chains, except for the AA‐grafted plates. The amount of absorbed water for the grafted layers formed increased with an increase in the number of grafted polymer chains. The autohesive strength increased with an increase in the wettability and water absorptivity of the grafted plates as well as the temperature and load on heat pressing. For all grafted plates substrate breaking at autohesive strength measurements was observed for grafted amounts 2–3 times as much as those at adhesive strength measurements. The substrate breakings for the HDPE and PP plates photografted with AA and DMAEMA at adhesive strength measurements were observed at lower grafted amounts compared with those photografted with MAA. This study has made it clear that the photografting of hydrophilic monomers onto polyolefin materials can markedly enhance autohesivity without any adhesives as well as the adhesivity for high grafted amounts. Therefore, polyolefin materials with improved autohesivity and adhesivity can be widely applied in adhesive fields, including for novel uses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2244–2252, 2003
1,3,5‐trihydroxy benzene as a surface modifier of carbon black and its effect on the filler–rubber interaction
Authors: Ganguly S. , Bhattacharya P. , Banerjee A. N. , Chakraborty S.
Published: January 2003

A surface‐modified rubber‐grade carbon black has been prepared by treating it with 1,3,5‐trihydroxy benzene (phluroglucinol) in aqueous solution at different molar concentrations. This modified carbon black has been used as one of the compounding ingredients with natural rubber. An attempt has been made to establish a concentration optimum for the modifier. Improved physicomechanical properties like hardness, heat buildup, hysteresis loss, and improved dynamic mechanical properties are observed for the compounded rubber. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2272–2278, 2003
Study of the isothermal curing of an epoxy prepreg by near‐infrared spectroscopy
Authors: Wang Qian , Storm Birgit K. , Houmøller Lars P.
Published: January 2003

The commercial epoxy prepreg SPX 8800, containing diglycidyl ether of bisphenol A, dicyanodiamide, diuron, and reinforcing glass fibers, was isothermally cured at different temperatures from 75 to 110°C and monitored via in situ near‐infrared Fourier transform spectroscopy. Two cure conditions were investigated: curing the epoxy prepreg directly (condition 1) and curing the epoxy prepreg between two glass plates (condition 2). Under both curing conditions, the epoxy group could not reach 100% conversion with curing at low temperatures (75–80°C) for 24 h. A comparison of the changes in the epoxy, primary amine, and hydroxyl groups during the curing showed that the samples cured under condition 2 had lower initial epoxy conversion rates than those cured under condition 1 and that more primary amine–epoxy addition occurred under condition 2. In addition, the activation energy under cure condition 2 (104–97 kJ/mol) was higher than that under condition 1 (93–86 kJ/mol), but a lower glass‐transition temperature of the cured samples was observed via differential scanning calorimetry. The moisture in the prepreg was assumed to account for the different reaction kinetics observed and to have led to different reaction mechanisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2295–2305, 2003
Water vapor sorption and transport in dense polyimide membranes
Authors: Huang Jingui , Cranford Richard J. , Matsuura Takeshi , Roy Christian
Published: January 2003

The sorption and transport of water vapor in five dense polyimide membranes were studied by thermogravimetry. The sorption isotherms of water vapor in the polyimides could be successfully interpreted by both the dual‐mode sorption model and the Guggenheim–Anderson–de Boer equation. The water vapor diffusion behavior was found to be nearly Fickian at higher water vapor activities, whereas non‐Fickian diffusion was observed at lower water activities. The phenomena could be well described by the mechanism of combined Fickian and time‐dependent diffusion. The diffusion coefficient and water vapor uptake in the polyimides were strongly dependent on the polymer molecular structure. Except for the polyimide prepared from 3,3′,4,4′‐diphenylsulfone tetracarboxylic dianhydride and 1,3‐bis(4‐aminophenoxy) benzene, the permeability of water vapor in the dense polyimide membranes predicted from the sorption measurement at 30°C corresponded well with the water vapor permeability measured at 85°C. Among the polyimides studied, pyromellitic dianhydride–4,4′‐diaminophenylsulfone (50 mol%)/4,4′‐oxydianiline (50 mol%) showed both high water sorption and diffusion and, therefore, high water vapor permeability, which for vapor permeation membranes is necessary for the separation of water vapor from gas streams. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2306–2317, 2003
Temperature distribution effects during polymerization of methacrylate‐based monoliths
Authors: Mihelič Igor , Koloini Tine , Podgornik Aleš
Published: January 2003

Monolithic stationary phases are becoming increasingly important in the field of liquid chromatography. Methacrylate‐based monoliths are produced via free‐radical bulk polymerization. The preparation of large‐volume monoliths is a major problem because the intensive heat released during polymerization causes distortion of the porous monolithic structure. This work presents experimental measurements of temperature distributions during polymerization in moulds of different sizes and at various experimental conditions. A mathematical model for the prediction of temporal and spatial temperature distribution during the polymerization of methacrylate‐based monolithic columns is introduced. The polymerization is described by an unsteady‐state heat conduction equation with the generation of heat related to the general kinetics of polymerization. Predictions from the mathematical model are in good agreement with the experimental measurements at different experimental conditions. A method for construction of large‐volume monolithic columns is presented and an attempt is made to adopt the developed mathematical model in annular geometry. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2326–2334, 2003
Copolymerizations of carbon dioxide and epoxides in the presence of rare earth coordinate catalyst
Authors: Guo Jin‐Tang , Wang Xin‐Ying , Xu Yong‐Shen , Sun Jing‐Wu
Published: January 2003

Carbon dioxide (CO2) as a direct material was copolymerized with epoxides to synthesize new aliphatic polycarbonates, and the copolymerization was catalyzed by the coordinate catalyst composed of rare earth yttrium phosphonate and triisobutylaluminum [Y(P204)3–A1(i‐Bu)3]. The epoxides used in this research included epichlorohydrin (ECH) and some new glycidol ether (GE) monomers prepared by the reaction of ECH and phenol or alcohol, such as α‐allyl glycidol ether, β‐chloroethyl glycidol ether, benzene glycidol ether, m‐tolyl glycidol ether, and benzyl glycidol ether. The copolymers were characterized by infrared (IR), 1H nuclear magnetic resonance (‐NMR), and dynamic mechanical analysis. The results show that Y(P204)3–A1(i‐Bu)3 had better catalytic activity in the copolymerization of CO2 with epoxide, and the copolymerization rate of aryl GE was distinctly higher than that of aliphatic GE. Dynamic mechanical analysis indicated the glass transition temperature Tg of the copolymers GE–CO2 were lower than that of ECH–CO2. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2356–2359, 2003
Thermal analysis of ultrafine wool powder
Authors: Xu Weilin , Guo Weiqi , Li Wenbin
Published: January 2003

Wool powder was produced from wool fiber by pretreatment and then ground by a specially designed machine. Scanning electron micrograph (SEM) photos show that ultrafine wool powder around 2 μm in diameter can be produced from fiber around 25 μm in the diameter, and most of the powder is in the form of needles. The powder can be widely applied in new biomedical material development and cosmetic products. Thermal analysis of thermogravimetry (TG) and differential scanning calorimetry (DSC) show that the temperature for moisture evaporation in the powder was elevated to around 150°C from the control wool fiber, which was around 120°C. As the powder particle size decreases, the temperature corresponding to the crystal cleavage and the destruction of the crosslinkages increased, which is perhaps mostly due to the new crosslinks and new crystal that were produced during powder processing. The temperature for the liquefaction was also elevated and the relative TG results show that the last residue of the powder after 600°C is higher than that of the control sample. The thermal results show that as the powder particle size decreases, the thermal stability increases slightly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2372–2376, 2003
Epidemiologic analysis of maternal factors and amniotic band defects
Authors: Werler Martha M. , Louik Carol , Mitchell Allen A.
Published: January 2003

BACKGROUND

The group of defects identified as amniotic bands includes amnion rupture sequence (ARS) and body wall complex (BWC). Little is known about risk factors for either ARS or BWC, except that maternal age has been shown to affect risk inversely.

METHODS

The present analysis used data collected from 1976 to 1998 as part of an ongoing case control study of birth defects in the metropolitan areas of Boston, Philadelphia, and Toronto. There were 73 cases with ARS and 11 cases with BWC. ARS cases were further subdivided according to affected structures: there were 53 with only limbs affected (ARS‐L) and 20 with nonlimb defects with or without limb defects (ARS‐NL). The control group comprised 12,227 subjects with other major malformations. Mothers were interviewed within 6 months of delivery about demographic, reproductive, medical, and behavioral factors.

RESULTS

Multivariate adjusted odds ratios for BWC were increased more than threefold for maternal age < 25 years and maternal education < 12 years, but neither estimate was statistically significant. Corresponding estimates for ARS‐L and ARS‐NL ranged from 1.3 to 1.5 and also were not statistically significant. Cases were less likely to be white non‐Hispanic than controls and the odds ratio for ARS‐NL excluded the null. The multivariate adjusted odds ratio (MVOR) for unplanned pregnancy and BWC was 1.9 (95% confidence interval, 0.5–6.7) compared to 1.2 and 1.0 for ARS‐L and ARS‐NL, respectively. Neither parity nor maternal smoking was associated with any case group. The MVORs for first trimester acetaminophen use in relation to ARS‐L and ARS‐NL risks were 2.1 (1.1–3.9) and 3.4 (1.1–10.3), respectively. Such use was less common among BWC cases (MVOR was 0.4; 0.1–1.4).

CONCLUSIONS

Risk estimates tended to be similar for ARS‐L and ARS‐NL cases but different for BWC cases, suggesting different etiologies. These data suggest that young maternal age, low maternal education, unplanned pregnancy, and non‐white/non‐Hispanic race/ethnicity might increase the risk of BWC in offspring. Increased risks for acetaminophen use should be interpreted with caution because they may be confounded by indication for use. Birth Defects Research (Part A) 67:68–72, 2003. © 2003 Wiley‐Liss, Inc.
A phylogenetic hypothesis for the origin of hiccough
Authors: Straus C. , Vasilakos K. , Wilson R. J. A. , Oshima T. , Zelter M. , Derenne J‐Ph. , Similowski T. , Whitelaw W. A.
Published: January 2003

The occurrence of hiccoughs (hiccups) is very widespread and yet their neuronal origin and physiological significance are still unresolved. Several hypotheses have been proposed. Here we consider a phylogenetic perspective, starting from the concept that the ventilatory central pattern generator of lower vertebrates provides the base upon which central pattern generators of higher vertebrates develop. Hiccoughs are characterized by glottal closure during inspiration and by early development in relation to lung ventilation. They are inhibited when the concentration of inhaled CO2 is increased and they can be abolished by the drug baclofen (an agonist of the GABAB receptor). These properties are shared by ventilatory motor patterns of lower vertebrates, leading to the hypothesis that hiccough is the expression of archaic motor patterns and particularly the motor pattern of gill ventilation in bimodal breathers such as most frogs. A circuit that can generate hiccoughs may persist in mammals because it has permitted the development of pattern generators for other useful functions of the pharynx and chest wall muscles, such as suckling or eupneic breathing. BioEssays 25:182–188, 2003. © 2003 Wiley Periodicals, Inc.
The CRP/MLP/TLP family of LIM domain proteins: Acting by connecting
Authors: Weiskirchen Ralf , Günther Kalle
Published: January 2003

In vertebrates, members of the cysteine‐rich protein (CRP) family are characterized by the presence of two LIM domains linked to short glycine‐rich repeats. These proteins mediate protein–protein interactions and are of fundamental importance for cell differentiation, cytoskeletal remodeling, and transcriptional regulation. To date, a vast amount of information about vertebrate CRPs has become available, including their biological functions, interacting partners, and three‐dimensional structures. Compatible with a molecular adapter role, structural data reveal that the LIM domains within these proteins represent completely independent folded units bridged by flexible linker regions. The physiological roles for individual CRPs was determined by targeted gene disruption analysis and by identification of common and specific binding partners by means of yeast and mammalian two‐hybrid screens. Several CRP‐like LIM domain proteins with close structural and sequence similarity were identified in arthropods, protozoas and plants, supporting the notion that this subset of LIM domain proteins has been highly conserved over the span of evolution thereby emphasizing the importance of their function. BioEssays 25:152–162, 2003. © 2003 Wiley Periodicals, Inc.
Fibrillar collagen: The key to vertebrate evolution? A tale of molecular incest
Authors: Boot‐Handford Raymond P. , Tuckwell Danny S.
Published: January 2003

Fibril‐forming (fibrillar) collagens are extracellular matrix proteins conserved in all multicellular animals. Vertebrate members of the fibrillar collagen family are essential for the formation of bone and teeth, tissues that characterise vertebrates. The potential role played by fibrillar collagens in vertebrate evolution has not been considered previously largely because the family has been around since the sponge and it was unclear precisely how and when those particular members now found in vertebrates first arose. We present evidence that the classical vertebrate fibrillar collagens share a single common ancestor that arose at the very dawn of the vertebrate world and prior to the associated genome duplication events. Furthermore, we present a model, ‘molecular incest’, that not only accounts for the characteristics of the modern day vertebrate fibrillar collagen family but demonstrates the specific effects genome or gene duplications may have on the evolution of multimeric proteins in general. BioEssays 25:142–151, 2003. © 2003 Wiley Periodicals, Inc.
Cancer therapy: switching off oncogenes
Authors: Pompetti Franca , Pilla Daniela , Giancola Raffaella
Published: January 2003

Cancer derives from a cell clone that has accumulated genetic and epigenetic changes that influence its phenotype and finally enable it to escape from the normal controls of proliferation. A recent paper shows that, in myc‐induced tumours, the inactivation of this oncogene produces the regression of the tumours and the differentiation of the tumour cells into mature osteocytes.1 In addition, a further reactivation of myc in these cells does not restore the malignant phenotype but induces apoptosis. This discovery could lead to an innovative therapeutic strategy. BioEssays 25:104–107, 2003. © 2003 Wiley Periodicals, Inc.
Professional development: Setting the context
Authors: Watts Gordon E. , Hammons James O.
Published: January 2003

Community college professional development has evolved and grown as a movement for over three decades. Although professional development has struggled at times and still faces some challenges, the need is firmly established, and it has become an essential institutional function.
Classified staff development: An integrated model
Authors: Friesen Kay
Published: January 2003

This chapter describes an integrated staff development program at Metropolitan Community College, Omaha, Nebraska, that more effectively meets the needs of classified staff than traditional staff development models.
Sources and information: Professional development in community colleges
Authors: Bara Stolzenberg Ellen
Published: January 2003

This chapter presents an annotated bibliography of resources on faculty and staff development at community colleges, including information on needs assessment, programs and initiatives at local and state levels, national data, and future needs.
Recent developments in toroid cavity autoclave engineering
Authors: Niessen Heiko G. , Trautner Peter , Backhausen Rolf , Woelk Klaus
Published: January 2003

A toroid cavity autoclave (TCA) is a metal pressure vessel that simultaneously functions as an NMR resonator. Since the introduction of the TCA concept, many adaptations and optimizations were put together to suit particular applications such as catalysis in supercritical fluids, rotating‐frame imaging of materials, and evaluation of transport phenomena. In this article, we present recent achievements in TCA engineering that were carried out for both major fields of research with TCAs, i.e., high‐pressure and imaging studies. A new modular TCA design is introduced that makes it possible to easily access all individual parts of the autoclave for maintenance and replacement. The TCA is double tuned to a high frequency for 1H and 19F resonances and a low frequency for hetero nuclei. It withstands pressures up to 400 bar at room temperature and 300 bar at temperatures up to 100°C. The autoclave sample volume is electrically separated into two compartments with only the lower compartment NMR sensitive. With the two‐compartment TCA, it is possible to monitor multiple‐phase systems or gas/liquid reactions in situ without sacrificing high‐resolution qualities of the probe. In addition, special features are presented, such as the utilization of a second pressure line for injecting key reagents that initiate a chemical reaction or for vigorously mixing gases with a reactive solution. A newly designed resistive heater that does not introduce stray magnetic fields is also described. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 16B: 15–21, 2003
Multilayer transverse gradient coil design
Authors: Leggett J. , Crozier S. , Blackband S. , Beck B. , Bowtell R.W.
Published: January 2003

In small, cylindrical gradient coils consisting of a single layer of wires, the limiting factor in achieving large magnetic field gradients is the rapid increase in coil resistance with efficiency. This behavior results from the decrease in the maximum usable wire diameter as the number of turns is increased. By adopting a multilayer design in which the coil wires are allowed to spread out into multiple layers wound at increasing radii, a more favorable scaling of resistance with efficiency is achieved, thus allowing the design of more powerful gradient coils with acceptable resistance values. By extending the theory used to design standard cylindrical gradient coils, mathematical expressions have been developed that allow the design of multilayer coils. These expressions have previously been applied to the design of a four‐layer z‐gradient coil. As a further development, the equations have now been modified to allow the design of multilayer transverse gradient coils. The variation in coil performance with the number of layers employed has been investigated for coils of a size suitable for use in NMR microscopy, and the effect of constructing the coil using wires or cuts in a continuous conducting surface has also been assessed. We find that at fixed resistance a small wire‐wound two‐layer coil offers an increase in efficiency of a factor of about 1.5 compared with a single‐layer coil. In addition, a two‐layer coil of 10‐mm inner diameter has been designed and built. This coil had an efficiency of 0.41 Tm−1 A−1, a resistance of 0.96 ± 0.01 Ω, and an inductance of 22.3 ± 0.2 μH. The coil produces a gradient that deviates from linearity by less than 5% over a central cylindrical region of interest of height and length 6.2 mm. © 2003 Wiley Periodicals, Inc. Concepts in Magnetic Resonance (Magn Reson Engineering) 16: 38–46, 2003.
Networks and history
Authors: Bearman Peter , Moody James , Faris Robert
Published: January 2003

Events and event structures compose the constituent elements of history. In order to construct historical accounts of event sequences, historians have to make cases. This article proposes a method for casing historical events. We illustrate the analytic strategy by considering a complex population of interrelated events that make up a narrative of revolution, counter revolution, and revolution in a small village in China. Implications for the methodology of historical social science are discussed. © 2003 Wiley Periodicals, Inc.
Sonographic detection of a malpositioned feeding tube causing esophageal perforation in a neonate
Authors: Maruyama Kenichi , Shiojima Takeshi , Koizumi Takenobu
Published: January 2003

We report a case of esophageal perforation caused by a malpositioned feeding tube in a neonate of extremely low birth weight, 632 g. The infant had respiratory distress, which increased rapidly when he was 6 days old. Radiography revealed right‐sided hydrothorax that had not been evident a day earlier but no sign of a perforated esophagus. We performed sonography, which revealed fluid in the right pleural cavity and extra‐esophageal placement of the feeding tube. Analysis of a fluid specimen obtained on thoracocentesis indicated that the fluid was feeding formula. The feeding tube's misplacement was confirmed sonographically by injecting a small amount of sterile distilled water into the tube and visualizing its entry into the pleural cavity. The feeding tube was removed, and antimicrobial agents were administered. When the infant was 15 days old, feeding resumed through another tube, the placement of which was verified radiographically. The infant was discharged when he was 118 days old with no severe complications, although he had mild chronic lung disease. Because radiography did not reveal the tube's misplacement in this case, we believe that the use of sonography can contribute to an early diagnosis of esophageal perforation in such cases. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:108–110, 2003
Sonographic measurements of normal gallbladder sizes in children
Authors: Yoo Jeong‐Hyun , Kwak Hyun‐Joo , Lee Myung‐Jun , Suh Jeong‐Soo , Rhee Chung‐Sik
Published: January 2003

Purpose

Our goal was to establish the range of sonographic measurements of normal gallbladders in children.

Methods

Six hundred ten children aged 0–16 years (male:female ratio, 1.5:1) with normal clinical and laboratory findings were included in this study. The sonographic parameters were the length, width, and calculated volume of the gallbladder, and the clinical parameters were the age, height, weight, and body surface area of the children. Statistical significance was determined through correlation and regression analyses.

Results

The length of the gallbladder showed significant positive correlations with age (r = 0.65), height (r = 0.67), weight (r = 0.63), and body surface area (r = 0.65; p < 0.01). The calculated volume of the gallbladder also showed moderate correlations with age (r = 0.53), height (r = 0.55), weight (r = 0.61), and body surface area (r = 0.57; p < 0.01). The gallbladder width showed modest but significant correlations with age (r = 0.48), height (r = 0.53), weight (r = 0.53), and body surface area (r = 0.55; p < 0.01). The highest correlation coefficients were found between the gallbladder length and subject age (r = 0.65; p < 0.01) and between the gallbladder length and subject height (r = 0.67; p < 0.01). For all correlations, statistical significance remained after regression analysis (p < 0.01).

Conclusions

Values for the size of the normal pediatric gallbladder are defined and will be helpful in the diagnosis of gallbladder abnormalities. © 2003 Wiley Periodicals, Inc. J Clin Ultrasound 31:80–84, 2003
Lymphangiogenesis in tumors: What do we know?
Authors: Reis‐Filho Jorge Sergio , Schmitt Fernando C.
Published: January 2003

Lymphangiogenesis, the growth of new lymphatic vessels, has long been regarded as a putative efficient pathway to neoplastic metastization. However, until recently consistent data regarding reliable lymphatic endothelial cell markers were lacking. Moreover, the presence of new formed lymphatic vessels was considered a largely disputable concept. Now, this scenario has changed significantly, owing to consistent reports describing novel lymphatic endothelial cell (LEC) markers, the demonstration of new formed lymphatic vessels within the bulk of the tumor in animal models and human neoplasms, and the characterization of the VEGF‐C/VEGFR‐3 pathway. We herein review the major breakthroughs in the field of lymphangiogenesis, with special emphasis on novel and reliable LEC markers, such as prox‐1, LYVE‐1, and podoplanin, as well as on the pathological assessment of lymphangiogenesis as a putative prognostic factor for human neoplasms. Microsc. Res. Tech. 60:171–180, 2003. © 2003 Wiley‐Liss, Inc.
Angiogenesis in endocrine glands: Special reference to the expression of vascular endothelial growth factor
Authors: Katoh Ryohei
Published: January 2003

Recent studies have shown that several angiogenic growth factors are produced and secreted by normal endocrine cells and are increased in pathological states of endocrine glands, including inflammation, hyperplasia, and neoplasia. Expression of corresponding receptors on epithelial cells and/or endothelial cells enables these angiogenic factors to influence growth and function of the endocrine tissues by auto‐ or paracrine mechanisms. Some of the angiogenic factors are also considered to be involved in angiogenesis, which is a critical process in tumor formation and progression. Vascular endothelial growth factor (VEGF) is regarded as one of most important angiogenic factors with specific effects on endothelial cell growth and vascular permeability, and is isolated from a variety of normal and neoplastic endocrine cells. In this article, recent studies on angiogenic factors, especially on expression of VEGF, are reviewed in the field of endocrine systems. Microsc. Res. Tech. 60:181–185, 2003. © 2003 Wiley‐Liss, Inc.
Vascular networks and endothelial cells in the rat experimental pituitary glands and in the human pituitary adenomas
Authors: Itoh Johbu , Serizawa Akihiko , Kawai Kenji , Ishii Yudo , Teramoto Akira , Osamura Robert Yoshiyuki
Published: January 2003

There has been considerable interest in the relationship between hormone‐secreting endocrine cells (HSEC) and their microvessels (MVN) in human pituitary gland. However, microcirculatory networks have rarely been studied in three dimensions (3D). Therefore, this study was designed to visualize and to reveal the relationship between hormone secreting endocrine cells and their microvessel environment including vascular endothelial cells in 3D using rat pituitary glands under various experimental conditions by confocal laser scanning microscopy (CLSM). By CLSM, the 3D distributions of MVN were visualized and revealed a relationship between HSEC and MVN in experimental pituitary glands and human pituitary adenomas. Therefore, 3D reconstructed imaging by CLSM is a useful technique with which to investigate the microvessel environment of hormone‐secreting cells and has the potential to reveal dynamic hormone‐secreting pathways. Microsc. Res. Tech. 60:231–235, 2003. © 2003 Wiley‐Liss, Inc.
Angiogenesis in pituitary adenomas
Authors: Yamada Shozo , Takada Kouji
Published: January 2003

Angiogenesis, which is the formation of new blood vessels from preexisting capillaries, plays an important role in tumor growth and metastasis. In this review, the focus is on angiogenesis in pituitary adenomas. Angiogenesis of pituitary adenomas has been assessed by studying tumor microvessel density using specific immunohistochemical markers to clarify the relationship between angiogenesis and tumor behavior. Unlike other organs, pituitary adenomas have significantly lower vascular densities as compared to nontumorous adenohypophysis, suggesting that the lack of significant angiogenesis may play a role in the slow pace of pituitary tumor growth and rarity of metastases. In addition, the relationship between microvessel density and various factors in pituitary adenomas is reviewed, including tumor types, age and sex, invasiveness, malignancy, several proliferative markers (MIB‐1 or Ki‐67). However, further studies will be needed, since many studies have reached opposite conclusions. Angiogenesis is a complex multistep process and several factors are found to be involved in each step of neovascularization, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and various other cytokines. VEGF and bFGF (or FGF‐2), which are the most potent angiogenesis inducers among them, have been studied by immunohistochemistry, in situ hybridization, or in vitro studies in normal or adenomatous pituitaries and these results are also discussed in this review. Microsc. Res. Tech. 60:236–243, 2003. © 2003 Wiley‐Liss, Inc.
Angiogenesis in normal and neoplastic pituitary tissues
Authors: Lloyd Ricardo V. , Vidal Sergio , Horvath Eva , Kovacs Kalman , Scheithauer Bernd
Published: January 2003

Angiogenesis, or the formation of new blood vessels, is a dynamic process needed for embryogenesis, post‐natal growth, morphogenesis, tumorigenesis, and for other biological processes. Angiogenesis is very important for tumor development and progression. This review examines the activators and inhibitors of angiogenesis with emphasis on the pituitary gland and pituitary neoplasms. Some of the proteins regulating angiogenesis in pituitary tumors such as vascular endothelial growth factor (VEGF) and VEGF receptors, fibroblasts growth factors (FGF), transforming growth factor beta (TGFB), interleukins, interferons, and matrix metalloproteinases (MMPs) and inhibitors of MMPs have been examined in animal and human pituitary tumor models. However, many other significant regulators of angiogenesis including angiopoietins, angiostatin, and thrombospondins have not been studied extensively in pituitary tumors to date. Newer concepts and developments in angiogenesis such as vasculogenic mimicry and gene therapy approaches to angiogenesis in cancer treatment are also discussed. Microsc. Res. Tech. 60:244–250, 2003. © 2003 Wiley‐Liss, Inc.
Development, growth, and plasticity in the crayfish olfactory system
Authors: Sandeman Renate , Sandeman David
Published: January 2003

Decapod crustaceans have a well‐defined olfactory system characterised by a set of chemosensitive sensilla grouped together in an array (the olfactory organ) on their antennules. Olfactory receptor neurons in the olfactory organ project exclusively to, and terminate in, cone‐shaped olfactory glomeruli in a discrete neuropil in the brain, the olfactory lobe. The olfactory organ appears to be the only afferent input to the olfactory lobe, making the system convenient for the study of its development and growth. The progression of development of the olfactory system is a continuum and can be traced from the first appearance of peripheral receptor cells and central stem cells through to the construction of the tracts and neuropils that constitute the adult system. Cell proliferation leading to the production of peripheral and central olfactory neurons can be observed with mitotic markers in both embryonic stages and in postembryonic growth. Cell proliferation in the olfactory system in crayfish persists throughout the lives of the animals and can be modulated by manipulating the living conditions imposed on growing animals. Large serotonergic neurons that are associated with the olfactory system may play a role in the regulation of cell proliferation. Microsc. Res. Tech. 60:266–277, 2003. © 2003 Wiley‐Liss, Inc.
Active dendritic properties constrain input‐output relationships in neurons of the central olfactory pathway in the crayfish forebrain
Authors: Mellon Deforest
Published: January 2003

Parasol cells are multimodal sensory interneurons of the hemi‐ellipsoid body in the decapod forebrain. In reptant crustaceans, the hemi‐ellipsoid body resides in the base of the eyecup, as an appendage to the terminal medulla. Parasol cells exhibit periodic depolarizations at a frequency of 0.5–1.0 Hz.. I have investigated the role of these periodic depolarizations and their superimposed impulse bursts in affecting the input/output properties of these neurons. Parasol cells receive input from photic, olfactory, and mechanosensory pathways. Strong stimulation over any one of these pathways can lead to the generation of one or more impulse bursts in a subset of parasol cells, timed to occur at the peak of successive periodic depolarizations. A role for the periodic depolarizations in the function of the parasol cells has yet to be established. I suggest the possibility that they may act as a nonlinear amplifier that boosts spatially‐summated excitatory synaptic potentials from strong or appropriate stimuli above threshold for burst generation. Another possibility includes modification of voltage‐sensitive ion channels in the dendritic membrane, permitting a more effective spread of excitatory synaptic currents to impulse or burst initiating zones. Impulse bursts may be a highly effective mode of output for these neurons, especially so as they occur synchronously in a subset of cells in response to strong sensory input. Furthermore, backfiring of bursts into the dendritic tree has a brief (2–3 second) but effective suppressive action upon weak sensory input, which can thereby be masked by stronger, burst‐generating input. This masking phenomenon is seen in other arthropod sensory interneurons, where its physiological basis appears to be a transient accumulation of intracellular Ca++ ions that open calcium‐sensitive potassium channels. Microsc. Res. Tech. 60:278–290, 2003. © 2003 Wiley‐Liss, Inc.
The circadian system of crayfish: A developmental approach
Authors: Fanjul‐Moles María Luisa , Prieto‐Sagredo Julio
Published: January 2003

Adult crayfish exhibit a variety of overt circadian rhythms. However, the physiological mechanisms underlying the overt rhythms are controversial. Research has centered on two overt rhythms: the motor activity and the retinal sensitivity rhythms of the genus Procambarus. The present work reviews various studies undertaken to localize pacemakers and mechanisms of entrainment responsible for these two rhythms in adult organisms of this crustacean decapod. It also describes an ontogenetic approach to the problem by means of behavioral, electrophysiological, and neurochemical experiments. The results of this approach confirm previous models proposed for adult crayfish, based on a number of circadian pacemakers distributed in the central nervous system. However, the coupling of rhythmicity between these independent oscillators might be complex and dependent on the interaction between serotonin (5‐HT), light, and the crustacean hyperglycemic hormone (CHH). The latter compound has, up until now, not been considered as an agent in the genesis and synchronization of the retinal sensitivity rhythm. Microsc. Res. Tech. 60:291–301, 2003. © 2003 Wiley‐Liss, Inc.