bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat‐Integrated Reactor Concepts for Hydrogen Production by Methane Steam Reforming
Authors: Kolios G. , Glöckler B. , Gritsch A. , Morillo A. , Eigenberger G.
Published: February 2005

Steam reforming of hydrocarbons is the major source of hydrogen on an industrial scale.

Conventional, large scale, processes for hydrogen production are not optimal for the decentralized, stand‐alone supply of hydrogen for fuel cell systems. Their major drawback is limited thermal efficiency due to restricted heat recovery from the reformer effluents. A promising approach to overcome these limitations is the utilization of multifunctional reactor concepts, integrating the major reaction steps and process heat management. Coupling endothermic and exothermic reactions into heat‐integrated processes can be realized in different ways. One possible design is based on micro‐structured devices employing recuperative heat exchange between the process streams. A comparable specific performance and functionality can be achieved with adiabatic fixed‐bed reactors, operating in a transient mode. A major issue for both alternatives is the proper axial distribution of the process heat. Novel design solutions, developed in our group, are reviewed in this paper. Detailed simulation studies, as well as proof‐of‐concept experiments, confirm their feasibility and potential to significantly enhance the efficiency of the process.
Application of Hierarchical Process Modelling Strategies to Fuel Cell Systems – Towards a Virtual Fuel Cell Laboratory
Authors: Hanke R. , Mangold M. , Sundmacher K.
Published: February 2005

There is an increasing need for adequate modelling and simulation tools for the design and analysis of fuel cell systems. In the present contribution, a modular modelling strategy is proposed, which is based on network theory for chemical engineering processes.

According to this network theory, a fuel cell system is decomposed into elementary units on several hierarchical levels (process unit level, phase level, storage level). After decomposition, the model formulation starts on the storage level: electrochemical source terms were combined with the diffusive and convective transport phenomena and state equations, forming an elementary unit of the phase level. On the phase level several thermodynamic phases (e.g. fluid compartments, electrode backings, catalyst layers, and the membrane electrolyte) are aggregated to a single fuel cell unit. Finally on the top level, the process unit level, single cells or fuel cell stacks are combined with other process units to form a complete process model.

This modelling procedure is demonstrated with a simple proton exchange membrane fuel cell system operated with hydrogen and oxygen.
Evaluation of the Financial and Environmental Feasibility of a Network of Distributed 200 kWe Combined Heat and Power Fuel Cell Systems on the Stanford University Campus
Authors: Colella W. G. , Niemoth C. R. , Lim C. Y. , Hein A. Ph.
Published: February 2005

This study investigates the economics of installing fuel cell generators on Stanford University's campus. This case study is internationally applicable because it resembles a more general case of U.S. universities, corporate campuses and European towns that i) own their own electricity and heating distribution networks, ii) incorporate combined heat and power (CHP), but iii) traditionally purchase heat and power from a commercial contractor. Based on detailed computer simulations of the University's electricity and heating network, the operation of a 200 kWe United Technologies CHP fuel cell system, and the cost structure of the University's supply options, the financial and environmental viability of these systems is analyzed by simulating a number of different scenarios which varied both the quantity and location of the fuel cell systems. It was concluded that i) the installation of fuel cell systems achieves greater fuel efficiency, lowered emissions, and up to 73 million dollars in savings for the University over 20 years including environmental incentives or up 21 million dollars in savings without any incentives; ii) the University maximizes savings through the installation of a quantity of fuel cell systems (84 systems) greater than that needed to provide all heat to the campus (72 systems) and less than that needed to provide all electricity (123 systems) when the systems are operated in electricity load following mode and do not export electricity back to the grid; and iii) the most financially attractive buildings in which to install systems are wet and dry laboratories, because their relatively high and constant electricity consumption increases system utilization, and therefore financial savings. These results are quantified in Figures 6 and 7. Results underscore the importance of operating systems in thermal networks.
Toxicity and outcome analysis of patients with recurrent head and neck cancer treated with hyperfractionated split‐course reirradiation and concurrent cisplatin and paclitaxel chemotherapy from two prospective phase I and II studies
Authors: Kramer Noel M. , Horwitz Eric M. , Cheng Jonathan , Ridge John A. , Feigenberg Steven J. , Cohen Roger B. , Nicolaou Nicos , Sherman Eric J. , Babb James S. , Damsker Jason A. , Langer Corey J.
Published: February 2005

Background.

Patients with local recurrences or new head and neck primary tumors in previously irradiated tissues have few options for salvage treatment. One option for select patients is to undergo reirradiation with concurrent chemotherapy. The purpose of this study is to report the initial clinical results of the Fox Chase phase I and II prospective reirradiation and chemotherapy studies.

Methods.

Between July 1996 and January 2002, 38 patients with locally recurrent unresectable squamous cell carcinoma of the head and neck were treated with concurrent chemotherapy and reirradiation on two prospective trials. All patients had received prior radiation therapy to the head and neck region (median dose, 64.2 Gy). Patients received cisplatin and paclitaxel along with hyperfractionated external beam radiation therapy to the site of recurrence.

Results.

The median follow‐up was 10 months. The median survival was 12.4 months, with actuarial rates of overall survival of 50% and 35% at 1 and 2 years, respectively. During follow‐up, 63% of patients experienced local progression of disease, all in the irradiated field. Actuarial progression‐free survival at 1 year was 33%, with a median time to progression of 7.3 months. Acute grade 3 to 4 toxicity included neutropenia, nausea, emesis, and mucositis.

Conclusions.

Hyperfractionated split‐course reirradiation and concurrent cisplatin and paclitaxel chemotherapy demonstrates durable locoregional control in select patients, although late toxicity may occasionally be significant. Only sites of disease recurrence need to be covered in the reirradiation fields. © 2005 Wiley Periodicals, Inc. Head Neck 27: XXX–XXX, 2005
Low frequency of BRAF and CDKN2A mutations in endometrial cancer
Authors: Salvesen Helga B. , Kumar Rajiv , Stefansson Ingunn , Angelini Sabrina , MacDonald Nicola , Smeds Johanna , Jacobs Ian J. , Hemminki Kari , Das Soma , Akslen Lars A.
Published: February 2005

Several pathways have been implicated in the pathogenesis of endometrial carcinoma. Based on recent reports, BRAF mutations provide an alternative route for activation of the RAS signalling pathway. The CDKN2A (p16) tumour suppressor gene is also altered in several tumour types. We therefore wanted to assess the pattern and prognostic impact of BRAF mutations and p16 alterations in endometrial carcinomas. Only 1 of 48 tumours (2%) was found to have a BRAF mutation in exon 15, whereas 8 of 45 tumours (18%) had a K‐ras mutation. Homozygous deletion, amplification, promoter region methylation or mutation of the p16 gene was seen in 6 cases (13%), and 18 cases (38%) carried polymorphisms in the p16 gene. All tumours with presence of p16 methylation, non‐sense mutation, deletion or amplification exhibited loss of p16 expression as evaluated by immunohistochemistry. Presence of a p16 hit was significantly correlated with high FIGO stage (p = 0.04), high histologic grade (p = 0.02), estrogen receptor negativity (p = 0.05), pathologic expression of p53 (p = 0.02), pathologic expression of p16 (p = 0.05) and poor survival (p = 0.02). There was also a significant correlation between loss of p16 expression and K‐ras mutations, pathologic p53 expression and serous papillary/clear cell histologic types (p = 0.05/p = 0.001/p = 0.002). In conclusion, BRAF mutation is an infrequent finding in endometrial carcinomas. Loss of p16 expression is seen in all cases with alterations of the p16 gene. The presence of a p16 hit might be important in a subset of endometrial carcinomas with aggressive clinical behaviour. However, the mechanism of p16 inactivation remains unclear for the majority of cases exhibiting loss of expression, but the interactions with K‐ras and p53 should be further studied. © 2005 Wiley‐Liss, Inc.
Dietary and other risk factors in women having fibrocystic breast conditions with and without concurrent breast cancer: A nested case‐control study in Shanghai, China
Authors: Li Wenjin , Ray Roberta M. , Lampe Johanna W. , Lin Ming‐Gang , Gao Dao Li , Wu Chunyuan , Nelson Zakia C. , Fitzgibbons E. Dawn , Horner Neilann , Hu Yong Wei , Shannon Jackilen , Satia Jessie A. , Patterson Ruth E. , Stalsberg Helge , Thomas David B.
Published: February 2005

Risk of breast cancer is increased in women with proliferative benign breast conditions. Most of these conditions, however, do not progress to breast cancer. The purpose of our study was to identify factors possibly associated with this progression. Women with proliferative fibrocystic breast conditions alone (214), and women with proliferative fibrocystic breast conditions and concurrent breast cancer (130), were compared to each other, and each of these groups of women were also compared to 1,070 controls; and 176 women with non‐proliferative benign breast conditions alone, and 155 also with breast cancer, were similarly compared. All study subjects were selected from a cohort of women enrolled in a trial of breast self‐examination in Shanghai. Women were interviewed to ascertain information on suspected risk factors for breast cancer and dietary habits. Conditional logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). Increased risks of both proliferative fibrocystic breast conditions alone, and with breast cancer, were associated with low parity, a prior benign breast lump and breast cancer in a first‐degree relative. Decreasing trends in the risk of both conditions with increasing intake of fruits and vegetables were observed. No factors were significantly associated with risk of breast cancer relative to risk of proliferative changes. Similar, but in some instances weaker, associations were observed for non‐proliferative fibrocystic conditions with and without breast cancer. The possible risk or protective factors that were observed in our study most likely alter the risk of breast cancer at an early stage in the carcinogenic process, and probably do not alter risk of progression from proliferative fibrocystic breast conditions to breast cancer. © 2005 Wiley‐Liss, Inc.
BRCA1: A locus‐specific “liaison” in gene expression and genetic integrity
Authors: Aiyar Sarah , Sun Jian‐long , Li Rong
Published: February 2005

Mutations in BRCA1 predominantly lead to elevated risks of breast and ovarian cancers. In contrast to the tissue‐specific nature of BRCA1tumors, the normal BRCA1 gene product functions in diverse nuclear events including transcription, DNA repair, and DNA damage checkpoint. Recent findings of physical and functional associations between BRCA1 and the RNA polymerase II (RNAPII)‐dependent transcription machinery may shed some light on this longstanding paradox of BRCA1 biology. Eukaryotic gene expression is now known to be a continuous process, whereby each step is physically and functionally connected to the next. In particular, RNAPII plays a pivotal role in coordinating transcription with various pre‐mRNA processing events and stress response. Interestingly, BRCA1 preferentially interacts with the processive form of RNAPII and proteins that regulate RNAPII activity and movement during transcription elongation. In response to DNA damage, BRCA1 dissociates from RNAPII and localizes to DNA damage sites. We propose that BRCA1 may coordinate multiple steps in gene expression, including transcription initiation, elongation, and pre‐mRNA processing via its interactions with the transcription machinery at selected gene loci. The same BRCA1‐associated transcription apparatus may serve as a sensor for stress signals and facilitate the transition from a transcription state to checkpoint/DNA repair state. Such a coordinating role of BRCA1 in gene expression may ensure the appropriate quantity and quality of the mature transcripts for certain breast and ovarian cancer‐related genes, as well as the genetic integrity of the breast and ovary tissues. © 2005 Wiley‐Liss, Inc.
Histone modifications as a platform for cancer therapy
Authors: Espino Paula S. , Drobic Bojan , Dunn Katherine L. , Davie James R.
Published: February 2005

Tumorigenesis and metastasis are a progression of events resulting from alterations in the processing of the genetic information. These alterations result from stable genetic changes (mutations) involving tumor suppressor genes and oncogenes (e.g., ras, BRAF) and potentially reversible epigenetic changes, which are modifications in gene function without a change in the DNA sequence. Mutations of genes coding for proteins that directly or indirectly influence epigenetic processes will alter the cell's gene expression program. Epigenetic mechanisms often altered in cancer cells are DNA methylation and histone modifications (acetylation, methylation, phosphorylation). This article will review the potential of these reversible epigenetic processes as targets for cancer therapies. © 2005 Wiley‐Liss, Inc.
Codominant expression of genes coding for different sets of inducible salivary polypeptides associated with parotid hypertrophy in two inbred mouse strains
Authors: López‐Solís Remigio O. , Kemmerling Ulrike
Published: February 2005

Experimental mouse parotid hypertrophy has been associated with the expression of a number of isoproterenol‐induced salivary proline‐rich polypeptides (IISPs). Mouse salivary proline‐rich proteins (PRPs) have been mapped both to chromosomes 6 and 8. Recently, mice of two inbred strains (A/Snell and A.Swiss) have been found to differ drastically in the IISPs. In this study, mice of both strains were used for cross‐breeding experiments addressed to define the pattern of inheritance of the IISP phenotype and to establish whether the IISPs are coded on a single or on several chromosomes. The IISP phenotype of individual mice was assessed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) of whole saliva collected after three daily stimulations by isoproterenol. Parental A/Snell and A.Swiss mice were homogeneous for distinctive strain‐associated IISP‐patterns. First filial generation (F1) mice obtained from the cross of A/Snell with A.Swiss mice expressed with no exception both the A/Snell and A.Swiss IISPs (coexpression). In the second filial generation (F2) both parental IISP phenotypes reappeared together with a majority of mice expressing the F1‐hybrid phenotype (1:2:1 ratio). Backcrosses of F1 × A/Snell and F1 × A.Swiss produced offsprings displaying the F1 and the corresponding parental phenotypes with a 1:1 ratio. No recombinants were observed among F2 mice or among mice resulting from backcrosses. Thus, genes coding for the IISPs that are expressed differentially in both mouse strains are located on the same chromosome, probably at the same locus (alleles) or at quite closely linked loci (nonalleles). © 2005 Wiley‐Liss, Inc.
NGX6 gene inhibits cell proliferation and plays a negative role in EGFR pathway in nasopharyngeal carcinoma cells
Authors: Wang Lili , Ma Jian , Li Jiang , Li Xiaoling , Zhang Qiuhong , Peng Shuping , Peng Cong , Zhou Ming , Xiong Wei , Yang Jianbo , Zhou Jie , Fan Songqing , Tan Chen , Yan Qun , Shen Shourong , Li Guiyuan
Published: February 2005

Nasopharyngeal carcinoma (NPC) is a common cancer in South China but is rare in other parts of the world. A novel NPC‐related gene was isolated by location candidate cloning strategy, whose expression was down‐regulated in NPC. This gene was designated human NGX6 (Genbank accession AF188239) and encoded a predicted protein of 338 amino acids that harbors an EGF‐like domain. The effects of NGX6 on cells from human NPC cell line HNE1 were investigated. The cells transfected with NGX6 had a markedly high expression of NGX6, leading to significant decrease in cell proliferation and the capability to form colonies in soft agar, delaying the G0–G1 cell cycle progression. Flow cytometry assay indicated that the expression of cyclin D1 significantly decreased in NGX6‐transfected HNE1 cells as well as cyclin A and E. There was a delay in tumor formation and a dramatic reduction in tumor size when cells transfected with NGX6 were injected into nude mice. In another way, we found NGX6 played a negative role in EGFR Ras/Mek/MAPK pathway. We propose that NGX6, as an EGF‐like domain gene, could delay cell cycle G0–G1 progression and thus inhibit cell proliferation by negatively regulating EGFR pathway in NPC cells and down‐regulating the expression of cyclin D1 and E. © 2005 Wiley‐Liss, Inc.
Discovery, regulation, and action of the major apoptotic nucleases DFF40/CAD and endonuclease G
Authors: Widlak Piotr , Garrard William T.
Published: February 2005

Toward the end of the 20th and beginning of the 21st centuries, clever in vitro biochemical complementation experiments and genetic screens from the laboratories of Xiaodong Wang, Shigekazu Nagata, and Ding Xue led to the discovery of two major apoptotic nucleases, termed DNA fragmentation factor (DFF) or caspase‐activated DNase (CAD) and endonuclease G (Endo G). Both endonucleases attack chromatin to yield 3′‐hydroxyl groups and 5′‐phosphate residues, first at the level of 50–300 kb cleavage products and next at the level of internucleosomal DNA fragmentation, but these nucleases possess completely different cellular locations in normal cells and are regulated in vastly different ways. In non‐apoptotic cells, DFF exists in the nucleus as a heterodimer, composed of a 45 kD chaperone and inhibitor subunit (DFF45) [also called inhibitor of CAD (ICAD‐L)] and a 40 kD latent nuclease subunit (DFF40/CAD). Apoptotic activation of caspase‐3 or ‐7 results in the cleavage of DFF45/ICAD and release of active DFF40/CAD nuclease. DFF40's nuclease activity is further activated by specific chromosomal proteins, such as histone H1, HMGB1/2, and topoisomerase II. DFF is regulated by multiple pre‐ and post‐activation fail‐safe steps, which include the requirements for DFF45/ICAD, Hsp70, and Hsp40 proteins to mediate appropriate folding during translation to generate a potentially activatable nuclease, and the synthesis in stoichiometric excess of the inhibitors (DFF45/35; ICAD‐S/L). By contrast, Endo G resides in the mitochondrial intermembrane space in normal cells, and is released into the nucleus upon apoptotic disruption of mitochondrial membrane permeability in association with co‐activators such as apoptosis‐inducing factor (AIF). Understanding further regulatory check‐points involved in safeguarding non‐apoptotic cells against accidental activation of these nucleases remain as future challenges, as well as designing ways to selectively activate these nucleases in tumor cells. © 2005 Wiley‐Liss, Inc.
Neurofeedback in adolescents and adults with attention deficit hyperactivity disorder
Authors: Butnik Steven M.
Published: February 2005

Neurofeedback is being utilized more commonly today in treating individuals who have attention deficit hyperactivity disorder (ADHD). Neurofeedback, which is based on theories that recognize the organic basis of ADHD, utilizes biofeedback to guide individuals to regulate their brain activity. Neurofeedback relies on research that has demonstrated that most individuals who have ADHD, as compared to matched peers, have excess slow wave activity and reduced fast wave activity. It provides immediate feedback to the individual about his or her brain wave activity in the form of a video game, whose action is influenced by the individual's meeting predetermined thresholds of brain activity. Over several sessions of using the video and auditory feedback, individuals reduce their slow wave activity and/or increase their fast wave activity. Individuals who complete a course of training sessions often show reduced primary ADHD symptoms. Research has shown that neurofeedback outcomes compare favorably to those of stimulant medication. © 2005 Wiley Periodicals, Inc. J Clin Psychol/In Session 61: 621–625, 2005.
Differentiation of noncancerous tissue and cancer lesions by apparent diffusion coefficient values in transition and peripheral zones of the prostate
Authors: Sato Chiho , Naganawa Shinji , Nakamura Tatsuya , Kumada Hisashi , Miura Shunichi , Takizawa Osamu , Ishigaki Takeo
Published: February 2005

Purpose

To compare the apparent diffusion coefficient (ADC) values of prostate cancer in both the peripheral zone (PZ) and the transition zone (TZ) with those of benign tissue in the same zone using echo‐planar diffusion weighted imaging with a parallel imaging technique.

Materials and Methods

A total of 29 consecutive male patients (mean age 61.3 years, age range 53–88 years) with suspected prostate cancer were referred for MR imaging. All patients underwent transrectal ultrasound (TRUS)‐guided biopsy of the prostate after MR imaging at 1.5 T, including ADC. For each patient, seven to 10 specimens were obtained from the prostate, and regions of interest (ROIs) were drawn on the ADC map by referring to the urologist's illustration of TRUS‐guided biopsy sites. ADC values of cancerous tissue in both the PZ and TZ were compared to those of noncancerous tissue in the same zone.

Results

Out of 29 patients, 23 had cancer tissue. In the 23 patients with cancer, the mean ADC value of all cancer ROIs and that of all noncancer ROIs, respectively, were 1.11 ± 0.41 × 10–3 and 1.68 ± 0.40 × 10–3 mm2/second (values are mean ± SD) (P < 0.01). The mean ADC value of TZ cancer ROIs and that of TZ noncancer ROIs, respectively, were 1.13 ± 0.42 × 10–3 and 1.58 ± 0.37 × 10–3 mm2/second (P < 0.01).

Conclusions

ADC measurement with a parallel imaging technique showed that ADC values of prostate cancer in both the PZ and TZ were significantly lower than those of benign tissue in the PZ and TZ, respectively. J. Magn. Reson. Imaging 2005;21:258–262. © 2005 Wiley‐Liss, Inc.
Real‐time Fourier velocity encoding: An in vivo evaluation
Authors: Macgowan Christopher K. , Kellenberger Christian J. , Detsky Jay S. , Roman Kevin , Yoo Shi‐Joon
Published: February 2005

Purpose

To compare in vivo real‐time Fourier velocity encoding (FVE), spectral‐Doppler ultrasound, and phase‐contrast (PC) magnetic‐resonance (MR) imaging.

Materials and Methods

In vivo velocity spectra were measured in the suprarenal and infrarenal aorta and the hepatic segment of the inferior vena cava of eight normal volunteers using FVE, and compared to similar measurements using Doppler ultrasound and gated PC MR imaging. In vivo waveforms were compared qualitatively according to flow pattern appearance (number, shape, and position of velocity peaks) and quantitatively according to peak velocity.

Results

Good agreement was obtained between peak velocities measured in vitro using FVE and PC MR imaging (R2 = 0.99, P = 2.10−6, slope = 0.97 ± 0.05). Qualitatively, the FVE and ultrasound measurements agreed closely in the majority of in vivo cases (excellent or good in 21/24 cases) while the PC MR method resolved fewer velocity peaks due to the inherent temporal averaging of cardiac‐gated studies (excellent or good agreement with FVE in 13/24 cases). Quantitatively, the FVE measurement of peak velocity correlated strongly with both ultrasound (R2 = 0.71, P = 2.10−7, slope = 0.81 ± 0.08) and PC MR (R2 = 0.85, P = 2.10−10, slope = 1.04 ± 0.08).

Conclusion

Real‐time MR assessment of blood‐flow velocity correlated well with spectral Doppler ultrasound. Such new methods may allow hemodynamic information to be acquired in vessels inaccessible to ultrasound or in patients for whom respiratory compensation is not possible. J. Magn. Reson. Imaging 2005;21:297–304. © 2005 Wiley‐Liss, Inc.
Balloon sizing and transcatheter closure of acute atrial septal defects guided by magnetic resonance fluoroscopy: Assessment and validation in a large animal model
Authors: Schalla Simon , Saeed Maythem , Higgins Charles B. , Weber Oliver , Martin Alastair , Moore Phillip
Published: February 2005

Purpose

To quantitatively assess atrial septal defects (ASDs) with small shunts using MRI followed by transcatheter closure monitored by MR fluoroscopy.

Materials and Methods

Acute ASDs were created in 14 pigs under x‐ray fluoroscopy. Six animals were studied in order to select MR‐compatible delivery systems and imaging strategies. ASDs in eight animals were examined with balloon sizing under MR fluoroscopy, flow measurements, and contrast media injections, after which transcatheter closure was performed under MR fluoroscopy. The delivery system was assembled from commercially available materials.

Results

The ratio of pulmonary to systemic flow (Qp/Qs) was reduced from 1.23 ± 0.15 before ASD closure to 1.07 ± 0.11 after ASD closure (P < 0.001). In two out of eight animals Qp/Qs was close to 1.0 before closure despite the presence of defects >15 mm. The ASDs were measurable with MR balloon sizing in all of the animals. Balloon sizing was identical with MR (16.9 ± 2.3 mm) and x‐ray fluoroscopy (17.1 ± 1.3 mm). The in‐house‐assembled delivery system allowed successful placement of closure devices under MR guidance.

Conclusion

Assessment and closure of small shunts with MR fluoroscopy is feasible. A barrier to the rapid implementation of transcatheter closure in patients is uncertainty about the MR safety of guidewires and device delivery systems. J. Magn. Reson. Imaging 2005;21:204–211. © 2005 Wiley‐Liss, Inc.
A multi‐proxy study of Holocene lake development, lake settlement and vegetation history in central Ireland
Authors: Selby K. A. , O'Brien C. E. , Brown A. G. , Stuijts I.
Published: February 2005

Stratigraphical investigations, geomorphological mapping, and diatom, plant macrofossil and pollen analyses were undertaken in and around two lakes in central Ireland to establish correlations between changes in lake conditions and catchment vegetation throughout the Holocene. Similar investigations of an adjacent mire reveal early Holocene changes in lake level and area. The palaeoecological data show high correlations related to variations in lake depth and area, catchment vegetation type, organic inputs and trophic status. Catchment‐scale deforestation is gradual and occurs through the Bronze and the Iron Ages, and the construction of a crannog in the early Medieval period (seventh century AD) appears to be associated with a widespread increase in deforestation and mixed agriculture in the catchment. Both pollen and plant macrofossils suggest that one of the crannogs was used for crop storage in addition to domestic and any other activities. In the early to middle Holocene similarities in the proxy‐data appear to be climatically driven through changing lake levels and areal extent whereas the later Holocene record is clearly dominated by anthropogenic changes within the catchment and the construction of crannogs in the lakes. The advantages of combining multi‐proxy indicators of lake hydroecology with the vegetation record are illustrated. Copyright © 2005 John Wiley & Sons, Ltd.
Palaeovegetational and palaeoenvironmental trends in the summit of the Guaiquinima massif (Venezuelan Guayana) during the Holocene
Authors: Rull Valentí
Published: February 2005

The 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

De 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

The 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

Parathyroid 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

Medullary 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

The 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.
Cystatin C, an easy and reliable marker for assessment of renal dysfunction in children with liver disease and after liver transplantation
Authors: Samyn Marianne , Cheeseman Paul , Bevis Lynsey , Taylor Rachel , Samaroo Beatrice , Buxton-Thomas Muriel , Heaton Nigel , Rela Mohamed , Mieli-Vergani Giorgina , Dhawan Anil
Published: February 2005

Renal dysfunction of variable severity is being increasingly recognized as a major complication of calcineurin inhibitors (CI), in some patients even necessitating renal transplantation. Close and effective monitoring of the renal function is indicated. Current methods for this monitoring are calculation of the glomerular filtration rate (GFR) based on creatinine or exogenous substances like 51Cr-EDTA. The first method is unreliable in children and the second is expensive and cumbersome. Cystatin C has been shown to be an accurate marker of glomerular filtration but has not been evaluated in a large cohort of pediatric patients before and after liver transplantation (LT). We evaluated the accuracy of cystatin C in 62 children (30 male) with LT, who had their 51Cr-EDTA measured on 40 occasions prior to LT and on 47 occasions after LT. The reciprocal of cystatin C correlated better with 51Cr-EDTA GFR (r = .78) than the reciprocal of creatinine (r = .40). Diagnostic accuracy in the identification of reduced GFR was assessed by ROC analysis. Cystatin C yielded the highest area under the ROC curve (AUC) in all groups assessed. From these data a cutoff level of cystatin C predicting 51Cr-EDTA GFR < 80 ml/min/1.73m2 was calculated. A level of 1.06 mg/L was found to have a sensitivity of 91% and a specificity of 81%. Applying this cutoff level in our patient group would have avoided 51Cr-EDTA GFR estimation in 43 of the 87 estimations. In conclusion, the use of this simple test could be recommended as screening of renal dysfunction in children with liver disease and after LT. (Liver Transpl 2005;11:344–349.)
Reconstruction of the middle hepatic vein tributary in a right lateral sector graft
Authors: Hashimoto Takuya , Sugawara Yasuhiko , Kishi Yoji , Akamatsu Nobuhisa , Matsui Yuichi , Kokudo Norihiro , Makuuchi Masatoshi
Published: February 2005

A right lateral sector graft (RLSG) was devised to overcome graft-size disparity in living donor liver transplantation (LDLT). When the RLSG has a middle hepatic vein (MHV) tributary, which drains a significant part of segment VI, the MHV tributary (V6) should be reconstructed to avoid congestion of the RLSG. In the donor operation, congestive area of segment VI was identified by 5 minutes of simultaneous clamping of V6 and the hepatic artery to the right lateral sector. An RLSG was harvested, preserving the V6 orifice. After plastic surgery of outflow veins including V6 using venous grafts, the RLSG was implanted into the recipient. In 19 patients who received RLSG in our institution, 2 RLSGs required V6 reconstruction. The postoperative courses of these two recipients and donors were uneventful. In conclusion, the present technique might be useful to avoid complications due to congestion and poor function of the relevant graft area and might help to expand the indications for RLSG. (Liver Transpl 2005;11:309-313.)
Safety of donor right hepatectomy without abdominal drainage: A prospective evaluation in 100 consecutive liver donors
Authors: Liu Chi Leung , Fan Sheung Tat , Lo Chung Mau , Chan See Ching , Yong Boon Hun , Wong John
Published: February 2005

Although the role of routine abdominal drainage after liver resection for tumors has been questioned, abdominal drainage after donor right hepatectomy for live donor liver transplantation (LDLT) has been a routine practice in most transplant centers. The present study aimed to evaluate the safety of the procedure without abdominal drainage. A prospective study was performed on 100 consecutive liver donors who underwent right hepatectomy for LDLT from July 2000 to September 2003. Biliary anatomy was carefully studied with intraoperative cholangiography using fluoroscopy. The middle hepatic vein was included in the graft in all except 1 patient. Parenchymal transection was performed using an ultrasonic dissector. The right hepatic duct was transected at the hilum and the stump was closed with 6-O polydioxanone continuous suture. Absence of bile leakage was confirmed with methylene blue solution instilled through the cystic duct stump. The abdomen was closed after careful hemostasis without drainage in all donors. The median age of the donors was 36 years (range 18–56 years). Median operative blood loss and operating time were 350 mL (range 42–1,400 mL) and 7.5 hours (range 5.2–10.7 hours), respectively. None of the donors required any blood or blood product transfusion. There was no operative mortality. The median postoperative hospital stay was 8 days (range 5–30 days). Postoperative morbidity occurred in 19 patients (19%), most of which were minor complications. No donor experienced bile leakage, intraabdominal bleeding, or collection. None required surgical, radiologic, or endoscopic intervention for postoperative complications, except for 1 donor who developed late biliary stricture that required endoscopic dilatation. All donors were well with a median follow-up of 32 months (range 11–50 months). In conclusion, with detailed study of the biliary anatomy and meticulous surgical technique, donor right hepatectomy can be safely performed without abdominal drainage. Abdominal drainage is not a mandatory procedure after donor hepatectomy in LDLT. (Liver Transpl 2005;11:314–319.)
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

Summary: 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.

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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.
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

Manganese 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

Genetically 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

Magnetic 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.