bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palaeovegetational and palaeoenvironmental trends in the summit of the Guaiquinima massif (Venezuelan Guayana) during the Holocene
Authors: Rull Valentí 
Published: February 2005

AbstractThe summits of the table mountains (tepuis) from the Neotropical Guayana region are remote environments suitable for palaeoecological studies with evolutionary, biogeographical and palaeoclimatic implications. Here, using palynological analyses of two radiocarbon‐dated peat bogs from a tepui summit, the Holocene palaeovegetational trends are reconstructed, and related to possible forcing factors. Because of the pristine character of the Guaiquinima summit, the recorded palaeoenvironmental changes are probably due to natural causes, which makes them valuable archives of the natural component of climatic change at a millennial time scale. The sequence begins with pioneer communities or meadows similar to present‐day ones, between about 8.4 and 4.5 ky BP. After this date, and until about 2 kyr BP the expansion of gallery forests suggests an increase in precipitation, documented also at regional (Neotropical) level. Between ca. 2 kyr BP and the last century, gallery forests are replaced by forests characteristic of the upper Guaiquinima altitudes, coinciding with a regional phase of reduced moisture. The present‐day meadows, established relatively quickly during the last century, substituted the former upland forests. In the locality studied, the main controlling factor of the vegetation during the Holocene seems to have been the moisture balance. In contrast to other tepui summits, there is no clear evidence for changes linked to temperature oscillations. This could be due to the elevation of the site, far from any characteristic ecological boundary, that makes it insensitive to this parameter. Copyright © 2005 John Wiley & Sons, Ltd.
Marginal formation of De Geer moraines and their implications to the dynamics of grounding‐line recession
Authors: Lindén Mattias , Möller Per 
Published: February 2005

AbstractDe Geer moraine ridges occur in abundance in the coastal zone of northern Sweden, preferentially in areas with proglacial water depths in excess of 150 m at deglaciation. From detailed sedimentological and structural investigations in machine‐dug trenches across De Geer ridges it is concluded that the moraines formed due to subglacial sediment advection to the ice margin during temporary halts in grounding‐line retreat, forming gradually thickening sediment wedges. The proximal part of the moraines were built up in submarginal position as stacked sequences of deforming bed diamictons, intercalated with glaciofluvial canal‐infill sediments, whereas the distal parts were built up from the grounding line by prograding sediment gravity‐flow deposits, distally interfingering with glaciolacustrine sediments. The rapid grounding‐line retreat (ca. 400 m yr−1) was driven by rapid calving, in turn enhanced by fast iceflow and marginal thinning of ice due to deforming bed conditions. The spatial distribution of the moraine ridges indicates stepwise retreat of the grounding line. It is suggested that this is due to slab and flake calving of the ice cliff above the waterline, forming a gradually widening subaqueous ice ledge which eventually breaks off to a new grounding line, followed by regained sediment delivery and ridge build‐up. Copyright © 2005 John Wiley & Sons, Ltd.
Kindred spirits of the endocrines: The training of the future endocrine surgeons
Authors: Pasieka Janice L. 
Published: February 2005

AbstractThe growth of knowledge and complexity now seen in General Surgery, has led to the sub‐specialization of the discipline. Although it is considered by some to have led to the fragmentation of General Surgery and the erosion of the specialty as we know it today, others would argue that it has and will continue to lead to a stronger division and a higher standard of care. Most would argue that a higher standard of care in focus areas stimulates research and research, in turn, improves the quality of education and training. Ultimately, improved education and training leads to better patient care. Organ‐specific specialization such as orthopedics and urology evolved from General Surgery and demonstrates this principle. Further sub‐specialization is likely inevitable, if the discipline of General Surgery is to remain a desired specialty. Endocrine surgery has evolved into a sub‐specialty of General Surgery, and over the last few decades has matured as a discipline. With this maturation comes the responsibility of defining the standard of care to be provided by surgeons involved in endocrine surgery. To achieve this goal, endocrine surgical associations and societies must set the standard of training both at the residency and postgraduate level. Where we are as a sub‐specialty, where we came from, and what it will take to meet this goal are discussed. J. Surg. Oncol. 2005;89:202–205. © 2005 Wiley‐Liss, Inc.
Parathyroid carcinoma
Authors: Mittendorf Elizabeth A. , McHenry Christopher R. 
Published: February 2005

AbstractParathyroid carcinoma is an uncommon malignancy. It accounts for less than 1% of cases of primary hyperparathyroidism (HPT). It is manifested by severe hypercalcemia and up to 50% of patients will have concomitant kidney or bone disease. The etiology of parathyroid carcinoma is unknown, however, the recently discovered HRPT2 gene, a tumor suppressor gene encoding for the protein parafibromin, has been implicated in the pathogenesis. Identification of inactivating germ‐line mutations in HRPT2 has significant implications for diagnosis and management. This article summarizes the genetic aspects of parathyroid carcinoma, reviews its clinical manifestations, and outlines the principles of surgical therapy, the indications for adjuvant therapy, and the use of bisphosphonate and calcimimetic agents for management of hypercalcemia. J. Surg. Oncol. 2005;89:136–142. © 2005 Wiley‐Liss, Inc.
Medullary thyroid carcinoma: Including MEN 2A and MEN 2B syndromes
Authors: Quayle Frank J. , Moley Jeffrey F. 
Published: February 2005

AbstractMedullary thyroid carcinoma (MTC) is a rare malignancy with several distinctive features that distinguish its management from other thyroid cancers. First, MTC may be sporadic (75% of cases), or may occur as a manifestation of the hereditary syndrome Multiple Endocrine Neoplasia type 2 (MEN 2) (25% of cases). Additionally, while MTC is more difficult to cure than differentiated thyroid cancer and has higher rates of recurrence and mortality, it is usually a slow growing tumor compared with other malignancies. Finally, unlike differentiated thyroid cancer, there is no known effective systemic therapy for MTC. MTC cells do not concentrate radioactive iodine, and MTC does not respond well to external beam radiation or conventional cytotoxic chemotherapy. These distinguishing features should be considered in planning surgical management of MTC. J. Surg. Oncol. 2005;89:122–129. © 2005 Wiley‐Liss, Inc.
Follicular thyroid lesions, elements that affect both diagnosis and prognosis
Authors: Zeiger Martha A. , Dackiw Alan P.B. 
Published: February 2005

AbstractThe precise diagnosis of follicular thyroid lesions is frequently debated because of the subjective nature of capsular invasion as well as both the histological and cytological characteristics. Furthermore, several different prognostic indices have been devised to examine prognosis associated with thyroid cancer. Herein, we describe how these confounding elements can affect the ability to accurately predict prognosis for patients with follicular thyroid lesions. J. Surg. Oncol. 2005;89:108–113. © 2005 Wiley‐Liss, Inc.
Synthesis of AB2 3‐ and AB4 5‐Miktoarm Star Copolymers Initiated from Dendritic Tri‐ and Penta‐Functional Initiators by Combination of Ring‐Opening Polymerization of ε‐Caprolactone and Nitroxide‐Mediated Radical Polymerization of Styrene
Authors: Miura Yozo , Sakai Yumi , Yamaoka Keisuke 
Published: February 2005

AbstractSummary: Well‐defined AB2 3‐ and AB4 5‐miktoarm star copolymers were prepared by combination of ring‐opening polymerization (ROP) and nitroxide‐mediated radical polymerization (NMRP) using dendritic tri‐ and penta‐functional initiators. Initially, two kinds of dendritic initiators having one benzylic OH and two or four TEMPO‐based alkoxyamine moieties were prepared. Using them, ROP of ε‐caprolactone was carried out at room temperature to give poly(ε‐caprolactone)s carrying two or four alkoxyamine moieties. NMRP of styrene from the poly(ε‐caprolactone)s was carried out at 120 °C to give AB2 3‐ and AB4 5‐miktoarm star copolymers, which were analyzed by 1H NMR and SEC. The $\overline M _{\rm n} {\rm s}$ increased linearly with conversion and the $\overline M _{\rm w} /\overline M _{\rm n} {\rm s}$ were in the range 1.10–1.37, showing that well‐defined AB2 3‐ and AB4 5‐miktoarm star copolymers were formed.Well‐defined AB2 3‐ and AB4 5‐miktoarm star copolymers were prepared by combination of ring‐opening polymerization (ROP) and nitroxide‐mediated radical polymerization (NMRP) using dendritic tri‐ and penta‐functional initiators.magnified imageWell‐defined AB2 3‐ and AB4 5‐miktoarm star copolymers were prepared by combination of ring‐opening polymerization (ROP) and nitroxide‐mediated radical polymerization (NMRP) using dendritic tri‐ and penta‐functional initiators.
Manganese‐enhanced magnetic resonance imaging of mouse brain after systemic administration of MnCl2: Dose‐dependent and temporal evolution of T1 contrast
Authors: Lee Jung Hee , Silva Afonso C. , Merkle Hellmut , Koretsky Alan P. 
Published: February 2005

AbstractManganese is a useful contrast agent for MRI of animals. Previously, it has been shown that systemic doses of MnCl2 provide unique contrast in the rodent brain, enabling visualization of neuroarchitecture. The present work investigates the dose and temporal dependence of brain enhancement after i.v. administration of MnCl2. Varying doses of MnCl2 (9–175 mg/kg) were administered to mice from 0 to 24 h prior to T1‐weighted manganese‐enhanced MRI (MEMRI) at 11.7 T. Pre‐MnCl2 T1 values measured in different brain regions ranged from 1.17 ± 0.03 to 1.76 ± 0.01 s. Post‐MnCl2 T1 measured 24 hr after administration of MnCl2 were significantly decreased, even after the lowest dose of MnCl2. The largest decreases occurred in the pituitary gland, where post‐MnCl2 T1 ranged from 231 ± 23 ms following the lowest dose to 143 ± 43 ms after the highest dose, while the smallest decreases were observed in cortex (post‐MnCl2 T1 = 1060 ± 5 ms for low dose and 637 ± 5 ms for high dose). The contrast resulting after 14 hr did not change up to 24 hr. Enhancement first occurred in subarachnoid spaces, followed by ventricles and periventricular tissues, and finally reached the remainder of the brain. Cortical layers were detected at higher doses (>88 mg/kg) and olfactory bulb layers were detected with the lowest dose (9 mg/kg). Temporal evolution of the enhancement of the olfactory bulb layers was observed. In some regions of the brain, such as hippocampus and thalamus, the changes in contrast detected between 2 and 14 hr used very specific pathways. These results demonstrate that both the dose and the time after MnCl2 can be manipulated to optimize brain contrast in a region‐specific manner. Published 2005 Wiley‐Liss, Inc.
Myocardial blood flow mapping in mice using high‐resolution spin labeling magnetic resonance imaging: Influence of ketamine/xylazine and isoflurane anesthesia
Authors: Kober Frank , Iltis Isabelle , Cozzone Patrick J. , Bernard Monique 
Published: February 2005

AbstractGenetically modified mouse models of many human diseases reflecting cardiovascular alterations are currently available. To date, little information on absolute myocardial perfusion in mice is found in the literature. High‐resolution quantitative myocardial blood flow maps (in‐plane resolution 156 × 312 μm2, slice thickness 1.5 mm) have been obtained noninvasively within 25 min at 4.7 T in 30 freely breathing C57/Bl6J mice using electrocardiogram‐ and respiration‐gated spin labeling magnetic resonance imaging (MRI). Regional myocardial blood flow measurements were carried out, and the effects of isoflurane at two different concentrations and ketamine/xylazine anesthesia were assessed. The mean blood flow value in the left ventricular myocardium was 6.0 ± 1.9 mL g−1 min−1 under ketamine/xylazine and 6.9 ± 1.7 mL g−1 min−1 (group average ± SD) under isoflurane (1.25%). Under the influence of higher isoflurane concentration (2.00%), myocardial blood flow increased dramatically to 16.9 ± 1.8 mL g−1min−1 with no significant change in heart rate. This work illustrates the feasibility of noninvasive quantitative myocardial perfusion mapping in mice using MRI. The study of the influence of anesthesia shows that myocardial blood flow is highly sensitive to isoflurane concentration. The method employed offers a noninvasive approach to longitudinal studies of murine models of cardiac disease. Magn Reson Med 53:601–606, 2005. © 2005 Wiley‐Liss, Inc.
Partially parallel imaging with phase‐sensitive data: Increased temporal resolution for magnetic resonance temperature imaging
Authors: Bankson James A. , Stafford R. Jason , Hazle John D. 
Published: February 2005

AbstractMagnetic resonance temperature imaging can be used to monitor the progress of thermal ablation therapies, increasing treatment efficacy and improving patient safety. High temporal resolution is important when therapies rapidly heat tissue, but many approaches to faster image acquisition compromise image resolution, slice coverage, or phase sensitivity. Partially parallel imaging techniques offer the potential for improved temporal resolution without forcing such concessions. Although these techniques perturb image phase, relative phase changes between dynamically acquired phase‐sensitive images, such as those acquired for MR temperature imaging, can be reliably measured through partially parallel imaging techniques using reconstruction filters that remain constant across the series. Partially parallel and non‐accelerated phase‐difference‐sensitive data can be obtained through arrays of surface coils using this method. Average phase differences measured through partially parallel and fully Fourier encoded images are virtually identical, while phase noise increases with g$\sqrt{\rm L}$ as in standard partially parallel image acquisitions. Magn Reson Med 53:658–665, 2005. © 2005 Wiley‐Liss, Inc.
Interindividual reproducibility of glutamate quantification using 1.5‐T proton magnetic resonance spectroscopy
Authors: Jang Dong‐Pyo , Lee Jong‐Min , Lee Eun , Park Sangjin , Kim Jae‐Jin , Namkoong Kee , Yoon Kang‐Jun , Kim In‐Young , Kim Sun I. 
Published: February 2005

AbstractThe goal of this study was to measure the interindividual reproducibility of glutamate quantification in 1.5‐T 1H MRS of human brains. To determine the effective echo time (TE) for glutamate quantification, spectra from a phantom and 12 participants were obtained with TE = 30, 35, 40, and 144 ms (repetition time (TR) = 2000 ms and volume of interest = 4 cm3). The average Cramér–Rao lower bounds for glutamate quantification using LCModel was lowest in two experiments when TE = 40 ms.Twenty‐one subjects participated in experiments that measured interindividual reproducibility of glutamate quantification. Spectra were acquired with TR = 6000 ms and TE = 40 ms. Results showed that the coefficients of variance were 11.0 and 13.1% in the anterior cingulate cortex and insula, respectively. This suggests that glutamate can be reproducibly measured from 1.5‐T 1H MRS with long TR, effective TE, and the LCModel. Magn Reson Med 53:708–712, 2005. © 2005 Wiley‐Liss, Inc.
Four‐phase single‐capillary stepwise model for kinetics in arterial spin labeling MRI
Authors: Li Ka‐loh , Zhu Xiaoping , Hylton Nola , Jahng Geon‐Ho , Weiner Michael W. , Schuff Norbert 
Published: February 2005

AbstractAn extended model for extracting measures of brain perfusion from pulsed arterial spin labeling (ASL) data while considering transit effects and restricted permeability of capillaries to blood water is proposed. We divided the time course of the signal difference between control and labeled images into four phases with respect to the arrival time of labeled blood water at the voxel of interest (tA), transit time through the arteries in the voxel (tex), and duration of the bolus of labeled spins (τ). Dividing the labeled slab of blood water into many discrete segments, and adapting numerical integration methods allowed us to conveniently model restricted capillary–tissue exchange based on a modified distributed parameter model. We compared this four‐phase single‐capillary stepwise (FPSCS) model with models that treat water as a freely diffusible tracer, using both simulations and experimental ASL brain imaging data at 1.5T from eight healthy subjects (24–80 years old). The FPSCS model yielded less errors in the least‐squares sense in fitting brain ASL data in comparison with freely diffusible tracer models of water (P = 0.055). These results imply that restricted permeability of capillaries to water should be considered when brain ASL data are analyzed. Magn Reson Med 53:511–518, 2005. Published 2005 Wiley‐Liss, Inc.
Molecular MR imaging of melanoma angiogenesis with ανβ3‐targeted paramagnetic nanoparticles
Authors: Schmieder Anne H. , Winter Patrick M. , Caruthers Shelton D. , Harris Thomas D. , Williams Todd A. , Allen John S. , Lacy Elizabeth K. , Zhang Huiying , Scott Michael J. , Hu Grace , Robertson J. David , Wickline Samuel A. , Lanza Gregory M. 
Published: February 2005

AbstractNeovascularization is a critical component in the progression of malignant melanoma. The objective of this study was to determine whether ανβ3‐targeted paramagnetic nanoparticles can detect and characterize sparse ανβ integrin expression on neovasculature induced by nascent melanoma xenografts (∼30 mm3) at 1.5T. Athymic nude mice bearing human melanoma tumors were intravenously injected with αvβ3‐integrin‐targeted paramagnetic nanoparticles, nontargeted paramagnetic nanoparticles, or αvβ3‐targeted‐nonparamagnetic nanoparticles 2 hr before they were injected with αvβ3‐integrin‐targeted paramagnetic nanoparticles (i.e., in vivo competitive blockade) and imaged with MRI. Contrast enhancement of neovascularity in animals that received ανβ3‐targeted paramagnetic nanoparticles increased 173% by 120 min. Signal contrast with nontargeted paramagnetic nanoparticles was approximately 50% less than that in the targeted group (P < 0.05). Molecular MRI results were corroborated by histology. In a competitive cell adhesion assay, incubation of ανβ3‐expressing cells with targeted nanoparticles significantly inhibited binding to a vitronectin‐coated surface, confirming the bioactivity of the targeted nanoparticles. The present study lowers the limit previously reported for detecting sparse biomarkers with molecular MRI in vivo. This technique may be employed to noninvasively detect very small regions of angiogenesis associated with nascent melanoma tumors, and to phenotype and stage early melanoma in a clinical setting. Magn Reson Med 53:621–627, 2005. © 2005 Wiley‐Liss, Inc.
Noise reduction in multi‐slice arterial spin tagging imaging
Authors: St. Lawrence K. S. , Frank J. A. , Bandettini P. A. , Ye F. Q. 
Published: February 2005

AbstractAttenuating the static signal in arterial spin tagging (ASSIST) was initially developed for 3D imaging of cerebral blood flow. To enable the simultaneous collection of cerebral blood flow and BOLD data, a multi‐slice version of ASSIST is proposed. As with the 3D version, this sequence uses multiple inversion pulses during the tagging period to suppress the static signal. To maintain background suppression in all slices, the multi‐slice sequence applies additional inversion pulses between slice acquisitions. The utility of the sequence was demonstrated by simultaneously acquiring ASSIST and BOLD data during a functional task and by collecting resting‐state ASSIST data over a large number of slices. In addition, the temporal stability of the perfusion signal was found to be 60% greater at 3 T compared to 1.5 T, which was attributed to the insensitivity of ASSIST to physiologic noise. Magn Reson Med 53:735–738, 2005. Published 2005 Wiley‐Liss, Inc.
Time‐resolved undersampled projection reconstruction magnetic resonance imaging of the peripheral vessels using multi‐echo acquisition
Authors: Du Jiang , Lu Aiming , Block Walter F. , Thornton Francis J. , Grist Thomas M. , Mistretta Charles A. 
Published: February 2005

AbstractThe hybrid projection reconstruction (PR) imaging provides high temporal resolution through an undersampled PR acquisition for the in‐plane dimensions and Cartesian slice encoding for the through‐plane dimension. The undersampling of projection data introduces streak artifact, which may severely compromise image quality. This study reports on a combination of multi‐echo acquisition with time‐resolved undersampled PR imaging and its application to peripheral magnetic resonance angiography. Multi‐echo acquisition improved imaging speed effectively, thereby reducing the undersampling streak artifact and improving the temporal resolution. The gradient distortion was reduced through gradient calibration and accurate k‐space trajectory measurement. Magn Reson Med 53:730–734, 2005. © 2005 Wiley‐Liss, Inc.
Electrochemical sensor for superoxide anion radical using polymeric iron porphyrin complexes containing axial 1‐methylimidazole ligand as cytochrome c mimics
Authors: Yuasa Makoto , Oyaizu Kenichi , Yamaguchi Aritomo , Ishikawa Masuhide , Eguchi Katsuya , Kobayashi Tomohiro , Toyoda Yuujiro , Tsutsui Satoshi 
Published: February 2005

AbstractA needle‐type electrochemical sensor for the facile detection of superoxide anion radical (O) was devised using an electrodeposited film of a polymeric porphyrin complex attached to a carbon microelectrode which was placed in a stainless steel 18G needle tube as an auxiliary electrode. The sensing element was prepared by means of electropolymerization of bromoiron(III) meso‐ tetra(3‐thienyl)porphyrin in the presence of 1‐methylimidazole in CH2Cl2 containing 100 mM tetrabutylammonium perchlorate (TBAP) as a supporting electrolyte, which gave a smooth film of the corresponding polymer. The film was electrochemically active to give a redox response near −0.05 V versus Ag/AgCl due to the iron(II/III) couple. The microsensor was applied to detect O produced by xanthine oxidation catalyzed by xanthine oxidase. The amperometric response for O was monitored at an electrode potential of 0.5 V versus the auxiliary electrode in a 10 mM phosphate buffer. The microsensor displayed a high catalytic activity for the oxidation of O and showed a linear relationship between the current and the O concentration. Axial coordination of an imidazole ligand to the iron porphyrin center enhanced selectivity for O by impeding the undesired coordination of H2O2 that resulted from the dismutation of O. Copyright © 2005 John Wiley & Sons, Ltd.