bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth retardation and destruction of experimental squamous cell carcinoma by interstitial radioactive wires releasing diffusing alpha‐emitting atoms
Authors: Cooks Tomer , Arazi Lior , Schmidt Michael , Marshak Gideon , Kelson Itzhak , Keisari Yona
Published: December 2007

In the present study, we examined the antitumoral effects caused by the release of alpha emitting radioisotopes into solid squamous cell carcinoma (SCC) tumors. Using a novel method termed DART (Diffusing Alpha‐emitters Radiation Therapy), we assessed the efficacy of short‐lived daughters of 224Ra releasing alpha particles, dispersing in the malignant tissue, to cause tumor growth retardation and destruction. It was carried out using specially designed wires loaded with 224Ra activities in the range of 7–42 kBq in a set of experiments performed on BALB/c and nude mice bearing metastatic SCC tumors derived from either mouse SQ2 or human CAL27 cell lines. The insertion of a DART wire to the center of 6–7 mm primary tumors, retarded tumor growth, reduced lung metastatic load, prolonged life expectancy and in some cases caused tumor eradication. These effects were enhanced either when treating smaller tumors or treating identical tumors with 2 DART wires. Similar experiments on human‐derived SCC tumors in nude mice were consistent with the outcomes of the murine model. Histological assessments revealed the tissue damage pattern, and indicated a role for the tumor vasculature in the dispersion of the atoms and the propagation of the damage. Our findings indicate that Diffusing Alpha‐emitting Radiation Therapy is effective in a model system using SCC primary tumors. The in situ destruction of primary solid tumors by DART is evidently a necessary step toward curing cancer and might be augmented by chemotherapy and other modalities such as immunotherapy or antigrowth factors agents. © 2007 Wiley‐Liss, Inc.
Daidzein but not other phytoestrogens preserves bone architecture in ovariectomized female rats in vivo
Authors: Somjen D. , Katzburg S. , Kohen F. , Gayer B. , Livne E.
Published: December 2007

Ovariectomy of immature female rats, results in significant decrease of trabecular bone volume and in cortical bone thickness. Previously, we found that estradiol‐17β (E2) restored bone structure of ovariectomized (Ovx) female rats to values obtained in intact sham‐operated female rats. E2 also selectively stimulated creatine kinase (CK) specific activity a hormonal‐genomic activity marker. In the present study, we compared the effects of E2 and the phytoestrogens: daidzein (D), biochainin A (BA), genistein (G), carboxy‐derivative of BA (cBA), and the SERM raloxifene (Ral) in Ovx, on both histological changes of bones and CK, when administered in multiple daily injections for 2.5 months. Bone from Ovx rats, showed significant disrupted architecture of the growth plate, with fewer proliferative cells and less chondroblasts. The metaphysis underneath the growth plate, contained less trabeculae but a significant increased number of adipocytes in the bone marrow. D like E2 and Ral but not G, BA, or cBA, restored the morphology of the tibiae, similar to that of control sham‐operated animals; the bony trabeculeae observed in the primary spongiosa was thicker, with almost no adipocytes in bone marrow. Ovariectomy resulted also in reduced CK, which in both epiphysis and diaphysis was stimulated by all estrogenic compounds tested. In summary, only D stimulated skeletal tissues growth and differentiation as effectively as E2 or Ral, suggesting that under our experimental conditions, D is more effective in reversing menopausal changes than any of the other isolated phytoestrogens which cannot be considered as one entity. J. Cell. Biochem. 103: 1826–1832, 2007. © 2007 Wiley‐Liss, Inc.
Cathelicidin stimulates colonic mucus synthesis by up‐regulatingMUC1andMUC2expression through a mitogen‐activated protein kinase pathway
Authors: Tai Emily K.K. , Wong Helen P.S. , Lam Emily K.Y. , Wu William K.K. , Yu L. , Koo Marcel W.L. , Cho C.H.
Published: December 2007

Mucus forms the physical barrier along the gastrointestinal tract. It plays an important role to prevent mucosal damage and inflammation. Our animal study showed that antibacterial peptide ‘cathelicidin’ increased mucus thickness and prevented inflammation in the colon. In the current study, we examined the direct effect and mechanisms by which the peptide increased mucus synthesis in a human colonic cell line (HT‐29). Human cathelicidin (LL‐37) dose‐dependently (10–40 µg/ml) and significantly stimulated mucus synthesis by increasing theD‐[6‐3H] glucosamine incorporation in the cells. Real‐time PCR data showed that addition of LL‐37 induced more than 50% increase inMUC1andMUC2mRNA levels. Treatment withMUC1andMUC2siRNAs normalized the stimulatory action of LL‐37 on mucus synthesis. LL‐37 also activated the phosphorylation of mitogen‐activated protein (MAP) kinase in the cells. A specific inhibitor of the MAP kinase pathway, U0126, completely blocked the increase ofMUC1andMUC2expression as well as mucus synthesis by LL‐37. Taken together, LL‐37 can directly stimulate mucus synthesis through activation ofMUC1andMUC2expression and MAP kinase pathway in human colonic cells. J. Cell. Biochem. 104: 251–258, 2008. © 2007 Wiley‐Liss, Inc.
Constitutive regulation ofCYP1B1by the aryl hydrocarbon receptor (AhR) in pre‐malignant and malignant mammary tissue
Authors: Yang Xinhai , Solomon Sandra , Fraser Lauren R. , Trombino Anthony F. , Liu Donghui , Sonenshein Gail E. , Hestermann Eli V. , Sherr David H.
Published: December 2007

The aryl hydrocarbon receptor (AhR) is a receptor/transcription factor which regulates cytochrome P450 (CYP) gene transcription and which is activated by environmental carcinogens, some of which are associated with increased breast cancer risk. Here, we show that the AhR is over‐expressed and constitutively active in human and rodent mammary tumors, suggesting its ongoing contribution to tumorigenesis regardless of tumor etiology. AhR regulation ofCYP1A1andCYP1B1was studied to determine if constitutively active AhR effects the same transcriptional outcomes as environmental chemical‐activated AhR. ElevatedAhRandCYP1B1but notCYP1A1before tumor formation in a rat model of mammary tumorigenesis suggested differentialCYP1B1regulation by a constitutively active AhR. This hypothesis was tested with human mammary gland cell lines which hyper‐expressAhRandCYP1B1but which express little or noCYP1A1.CYP1B1expression was diminished by repression of AhR activity or by AhR knockdown, demonstrating AhR control of basalCYP1B1levels. ChIP assays demonstrated constitutive AhR binding to bothCYP1A1andCYP1B1promoters, demonstrating that differentialCYP1A1andCYP1B1regulation by constitutively active AhR does not result from different amounts of promoter‐bound AhR. While increasing AhR binding to bothCYP1A1andCYP1B1, 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin inducedCYP1A1mRNA in both a malignant and non‐malignant line but increased onlyCYP1B1mRNA in the malignant line, again demonstrating that the level of promoter binding does not necessarily correlate with gene mRNA levels. These studies suggest that constitutively active AhR mediates different molecular outcomes than environmental chemical‐activated AhR, and further implicate the AhR in mammary tumorigenesis. J. Cell. Biochem. 104: 402–417, 2008. © 2007 Wiley‐Liss, Inc.
Complications and limitations related to periprostatic local anesthesia before TRUS‐guided prostate biopsy
Authors: Turgut Ahmet T. , Ölçücüoğlu Esin , Koşar Pınar , Geyik Pınar Özdemir , Koşar Uğur
Published: December 2007

Purpose

To assess the frequency of complications specifically related to local anesthetic infiltration prior to transrectal ultrasound (TRUS)‐guided prostate biopsy.

Methods

A total of 200 patients receiving 10 cm3 (5 cm3 on each side) of 2% lidocaine injected around the periprostatic nerve plexus under TRUS guidance before prostate biopsy were included. Various complications presumed to be associated with local anesthesia were noted during and after the biopsy procedure. Two weeks later, periprostatic tissue integrity and vascularization were re‐examined with TRUS Doppler examination to assess for fibrosis or infection.

Results

The most common finding was pain due to puncture with the needle used for local anesthesia (27%). Also recorded were the need for repeated injections during the biopsy procedure (4.5%), symptoms associated with systemic lidocaine toxicity (2%), urinary incontinence (1.5%), and degradation of the image resolution due to anesthetic injection (1%). Increased vascularization within the periprostatic region was uncommon (2%) on the 2‐week follow‐up examination. No TRUS finding consistent with rectal wall hematoma or other periprostatic change and no erectile dysfunction associated with the procedure occurred. There was a significant difference in overall pain scores between the subgroups of patients (p < 0.001).

Conclusion

TRUS‐guided periprostatic nerve blockade is an effective method for relieving discomfort from prostate biopsy with very few complications. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2008
Hexamethylene bisacetamide leads to reduced helper virus‐free HSV‐1 amplicon expression titers via suppression of ICP0
Authors: Burris Clark A. , de Silva Suresh , Narrow Wade C. , Casey Ann E. , Lotta Jr Louis T. , Federoff Howard J. , Bowers William J.
Published: December 2007

The herpes simplex virus (HSV)‐derived amplicon vector has evolved into a promising gene transfer platform for widespread DNA delivery in gene replacement strategies and vaccine development given its ease of molecular manipulation, large transgene capacity, and transduction efficiencies of numerous cell types in vivo. The recent development of helper virus‐free packaging methodologies bodes well for this vector system in its eventual implementation as a clinically viable therapeutic modality. For realization of clinical application, efforts have been made to enhance yields and quality of helper‐free amplicon stocks. Hexamethylene bisacetamide (HMBA), a hybrid polar compound that exhibits stimulatory activity of HSV‐1 immediate‐early gene expression, has been employed as a standard reagent in helper virus‐free packaging given its purported mode of action on virus gene expression kinetics. Unexpectedly, we have found that HMBA exhibits no titer‐enhancing activity; in contrast, the compound enhances the proportion of amplicon virions that are non‐expressive. Omission of HMBA during vector packaging led to a marked reduction in the ratios of vector genome‐transducing to transgene‐expressing virions. This effect was neither packaging‐cell‐specific nor amplicon‐promoter‐dependent. Analysis of resultant vector stocks indicated amplicon genome replication/concatenation was unaffected, but the level of particle‐associated ICP0 was reduced in stocks packaged in the presence of HMBA. Inclusion of a co‐transfected, ICP0‐expressing plasmid into the packaging process led to significant rescue of amplicon expression titers, indicating that regulation of ICP0 concentrations is critical for maintenance of the amplicon genome expressive state. Copyright © 2007 John Wiley & Sons, Ltd.
Echo‐planar imaging for MRI evaluation of intrathoracic tumors in murine models of lung cancer
Authors: Bankson James A. , Ji Lin , Ravoori Murali , Han Lin , Kundra Vikas
Published: December 2007

Purpose

To evaluate the efficacy of fast cardiac‐ and respiratory‐gated MRI acquisition methods for noninvasive assessment of tumor volume in murine models of lung cancer.

Materials and Methods

A total of 21 mice bearing either human small‐cell (N417) or non‐small‐cell (H460) lung tumors were scanned using combinations of respiratory‐gated computed tomography (CT) imaging, cardiac‐ and respiratory‐gated multishot spin‐echo echo‐planar imaging (SE‐EPI), and cardiac‐ and respiratory‐gated spoiled gradient echo (SPGR). Tumor depiction at 4.7T was qualitatively and quantitatively compared with CT and tissue cross sections. MRI‐based measures of tumor volume were compared with ex vivo measurement of tumor mass.

Results

Tumors appeared hyperintense on T2‐weighted EPI images, providing positive intrinsic contrast between tumors and surrounding tissues. Tumor boundaries were better distinguished by EPI and SPGR with T1‐reducing contrast enhancement when tumor abutted other tissues than by CT or SPGR without contrast. Tumor volumes measured from EPI images correlate well with ex vivo measurements of tumor mass (P < 0.001, r2 = 0.99) and volume (P < 0.01, r2 = 0.98) over a wide range of tumor sizes.

Conclusion

Respiratory‐ and cardiac‐gated multishot EPI enables accurate, noninvasive assessment of tumor in murine models of lung cancer using a sequence that requires approximately two minutes to complete. J. Magn. Reson. Imaging 2008. © 2007 Wiley‐Liss, Inc.
Apparent T2relaxation times of lipid and macromolecules: A study of high‐grade tumor spectra
Authors: Opstad Kirstie S. , Griffiths John R. , Bell B. Anthony , Howe Franklyn A.
Published: December 2007

Purpose

To determine T2relaxation times of lipid and macromolecules (Lip/MMs) observed by1H magnetic resonance spectroscopy (1H MRS) of metastases (MET) and glioblastomas (GBM), so that they may be better characterized.

Materials and Methods

1H spectra were acquired at multiple echo times from brain lesions using point‐resolved spectroscopy sequence (PRESS) at TE = 30 msec either with metabolite‐nulling (six GBM and 11 MET), or without metabolite‐nulling (four MET and one mucocele). All lesions were previously untreated and had subsequent histopathological classification.

Results

The T2of the 1.3‐ppm Lip/MM peak was concentration‐dependent, but at high concentrations it was significantly different (P= 0.015) between GBM (42 ± 6 msec) and MET (63 ± 18 msec). The broad 2.05‐ppm and 0.09‐ppm Lip/MM peaks had similar T2s in MET and GBM. The T2of the narrow 2.05‐ppm Lip/MM peak sometimes observed had a T2of 100 ± 17 msec in MET and 75 msec in the mucocele.

Conclusion

We observed significantly higher T2of the 1.3‐ppm Lip/MM peak in MET compared with GBM at high 1.3‐ppm proton concentrations, in agreement with a higher 1.3/0.9‐ppm peak ratio found in MET. The relatively long T2of the 2.05‐ppm Lip/MM peak sometimes observed in MET may cause it to be confused with N‐acetyl aspartate (NAA). J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Suspected chronic pancreatitis with normal MRCP: Findings on MRI in correlation with secretin MRCP
Authors: Balci N. Cem , Alkaade Samer , Magas Louis , Momtahen Amir Javad , Burton Frank R.
Published: December 2007

Purpose

To review pancreatic MRI findings and their relationship with estimated pancreatic exocrine function on secretin‐stimulated MR cholangiopancreatography (S‐MRCP) in patients with clinically suspected chronic pancreatitis and normal baseline MRCP findings.

Materials and Methods

MRI findings of 26 patients with normal pancreatic duct diameter and without side branch ectasia on MRCP were evaluated. A single radiologist assessed pancreatic size, pancreatic signal intensity ratio (SIR), and arterial enhancement ratio (A/V) at head, body, and tail of the pancreas on T1‐weighted fat‐suppressed and serial contrast‐enhanced images at a single session. Combined findings were graded with a composite score. Serial S‐MRCP was performed at the same session with standard MRI. Correlation and differences between MRI findings and associated grade of duodenal filling (DF) or the degree of pancreatic duct caliber change (PDC) were analyzed.

Results

Seven patients revealed normal and 19 patients abnormal MRI findings. Significant correlation was present between the degree of DF and mean values of pancreatic size (r = 0.748), SIR (r = 0.610), A/V (r = 0.466), composite score (r = 0.833), and PDC (r = 0.554) separately. PDC correlated with SIR (r = 0.413) and composite score (r = 0.452), but not with A/V or pancreatic size. Significant differences were present between normal and abnormal DF grades in terms of mean values of associated findings of size (P = 0.001), SIR (P = 0.008), A/V (P = 0.019), and PDC (P = 0.001).

Conclusion

Patients with clinically suspected chronic pancreatitis and normal MRCP findings may have a spectrum of MRI findings that correlate with the estimated pancreatic exocrine insufficiency on S‐MRCP with the increasing number of combined findings. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.
Increased plasma membrane localization of O‐glycosylation‐deficient mutant of synaptotagmin I in PC12 cells
Authors: Kanno Eiko , Fukuda Mitsunori
Published: December 2007

Synaptotagmin I (Syt I) is a Ca2+‐binding protein on synaptic vesicles and presumably functions as a Ca2+ sensor for neurotransmitter release. Native Syt I protein in neuroendocrine PC12 cells undergoes several posttranslational modifications, such as O‐glycosylation, N‐glycosylation, and fatty acylation, and the latter two modifications have been shown to be required for the proper function of murine Syt I in PC12 cells. However, nothing is known about the physiological significance of the O‐glycosylation of Syt I in dense‐core vesicle exocytosis in PC12 cells. In this study, we created an O‐glycosylation‐deficient mutant (named TA = T15A/T16A) and an N‐glycosylation‐deficient mutant of Syt I (named T26A) and investigated their subcellular distribution in Syt I‐deficient PC12 cells, where other Syt isoforms (e.g., IV and IX) and other membrane trafficking proteins (e.g., Rab27A, SNAP‐25, syntaxin‐1, and VAMP‐2) are normally expressed. We found that some cells expressing high level of recombinant wild‐type (WT) Syt I protein show mistargeting of Syt I(WT) protein to the plasma membrane, whereas most of the cells show normal dense‐core vesicle localization of Syt I(WT) protein. Similar mistargeting was also observed in cells expressing high levels of the Syt I(T26A) and Syt I(TA) mutants, but the mistargeting of the Syt I(TA) mutant to the plasma membrane was much more evident than with the Syt I(WT) or (T26A) mutant. The results indicate that O‐glycosylation, not N‐glycosylation, is partially involved in efficient targeting of Syt I protein to dense‐core vesicles in PC12 cells. © 2007 Wiley‐Liss, Inc.
Receptor for advanced glycation end products (RAGE) mediates neuronal differentiation and neurite outgrowth
Authors: Wang Lingyan , Li Shitao , Jungalwala Firoze B.
Published: December 2007

The receptor for advanced glycation end products (RAGE) plays a crucial role in several disease processes, such as diabetes, inflammation, and neurodegeneration. In this article we report multiple roles of RAGE in neuronal differentiation and neurite outgrowth. In retinoic‐induced P19 embryonic carcinoma stem cells, silencing the expression of RAGE by RNA interference (RNAi) blocked differentiation of the P19 cells into neuronal cells and enhanced the formation of vimentin‐positive fibroblast‐like cells. RAGE knockdown inhibited retinoic acid–induced activation and blocked nuclear translocation of NF‐κB, suggesting RAGE regulates activation of NF‐κB. RAGE was also shown to be involved in survival of P19 cells during retinoic acid differentiation. Additionally, knockdown of RAGE strongly inhibited neurite outgrowth in retinoic acid–differentiated P19 cells, indicating that RAGE is required for neurite outgrowth of differentiated P19 cells. Retinoic acid–treated P19 cells activated GTPases, Rac1, and Cdc42. This activation of the GTPases was inhibited in RAGE‐knockdown cells. In primary cerebellar granule neurons, the knockdown of RAGE also inhibited neurite outgrowth. In these cells, overexpression of dominant‐negative forms of Rac1 and Cdc42 inhibited neurite outgrowth, whereas overexpression of constitutively active forms of Rac1 and Cdc42 in RAGE‐deficient neurons restored neurite outgrowth, indicating that RAGE mediated neurite outgrowth through the Rac1/Cdc42 pathway. This is the first report on the role of RAGE in cell lines and primary neurons, as determined by RNAi knockdown. © 2007 Wiley‐Liss, Inc.
Cytoarchitectonics and afferent/efferent reorganization of neurons in layers II and III of the lateral entorhinal cortex in the mouse pilocarpine model of temporal lobe epilepsy
Authors: Ma Dong Liang , Tang Yong Cheng , Tang Feng Ru
Published: December 2007

With the mouse pilocarpine model of temporal lobe epilepsy (TLE), we showed a progressive loss of both principal cells and calbindin (CB)‐, calretinin (CR)‐, and parvalbumin (PV)‐immunopositive interneurons in layers II–III of lateral entorhinal cortex (LEnt) from 2 months to 1 year after pilocarpine‐induced status epilepticus (PISE). In the efferent pathway of LEnt, more Phaseolus vulgaris leucoagglutinin (PHA‐L)‐labelled en passant and terminal boutons with larger diameters were shown in the hippocampus and subiculum; in the prefrontal, piriform, and perirhinal cortices; and in the amygdaloid complex in experimental mice at the two time points compared with the control after iontophoretical injection of an anterograde tracer PHA‐L into the LEnt. Furthermore, the numbers of CB‐ or CR‐immunopositive neurons contacted by PHA‐L‐labelled en passant and terminal boutons decreased in most of these areas at 2 months or 1 year after PISE. In the afferent pathway of LEnt, the numbers of retrogradely labelled neurons were reduced significantly in the ipsilateral piriform cortex and endopiriform nucleus at 2 months and 1 year and in the reuniens thalamic nucleus only at 1 year after injection of a retrograde tracer cholera toxin B subunit (CTB) into the LEnt. The percentages of the number of CTB and CB or CR double‐labelled neurons of all the retrogradely labelled neurons were also decreased in the reunions thalamic nucleus at 1 year after PISE. It is concluded that both cytoarchitectonic change and reorganization of afferent and efferent pathways in LEnt may be involved in the occurrence of TLE. © 2007 Wiley‐Liss, Inc.
The role of Raman spectroscopy in the research on sp‐hybridized carbon chains: carbynoid structures polyynes and metal polyynides
Authors: Cataldo Franco
Published: December 2007

This paper is an account of the author's works on the synthesis of carbynoid structures through the Glaser and the Cadiot‐Chodkiewicz reactions. Related topics are covered, such as the synthesis of the polyynes in solution with the submerged electric arc technique or with an improved use of the Glaser synthesis. The isolation of polyyne chains in the solid state as stable solids, i.e. as copper or silver complexes called polyynides, is covered as well. In all these research works, the Raman spectroscopy emerges as a powerful and indispensable tool for the characterization of such molecules and materials.

The use of Raman spectroscopy in combination with solid‐state 13C‐NMR showed that the carbonaceous solids produced in the early attempts of carbyne synthesis were not made of pure carbyne as desired and as claimed in the past, but consisted of three types of hybridized carbon atoms simultaneously present in the solid: the sp, sp2 and sp3. In such carbonaceous solids, the sp structures are called carbynoid structures. The reason for the formation of these mixed forms of carbon was ascribed to the fact that the carbon chains are not stable and in the solid state they tend to cross‐link forming in fact sp2‐ and sp3‐carbon atoms from the original sp‐hybridized carbon atoms.

Polyynes are easily accessible through the submerged carbon‐arc synthesis or alternatively, with the laser ablation of graphite particles submerged in an opportune solvent. Surface enhanced Raman spectroscopy (SERS) is a powerful tool to record the spectra of these molecules in dilute solutions. The best SERS spectra were recorded by using colloidal silver nanoparticles.

However, polyynes can be complexed with copper or silver to form polymeric derivatives called polyynides. In this way, the polyyne chains are stabilized in air at room temperature and beautiful Raman spectra have been recorded showing the triple bonds stretching bands. Copyright © 2007 John Wiley & Sons, Ltd.
Improper hydrogen bonding and motional narrowing in binary mixtures of 2‐ and 3‐bromopyridine in methanol probed by polarized Raman study and DFT calculations
Authors: Ojha Animesh K. , Srivastava Sunil K. , Schlücker S. , Kiefer W. , Asthana B. P. , Singh Ranjan K.
Published: December 2007

A concentration‐dependent Raman study of the ν(CBr) stretching and trigonal bending modes of 2‐ and 3‐Br‐pyridine (2Br‐p and 3Br‐p) in CH3OH was performed at different mole fractions of the reference molecule, 2Br‐p/3Br‐p, from 0.1 to 0.9 in order to understand the origin of blue/red wavenumber shifts of the vibrational modes due to hydrogen‐bond formation. The appearance of additional Raman bands in these binary systems at ∼617 cm−1in the case of 2Br‐p and at ∼618 cm−1 in the case of 3Br‐p compared to neat bromopyridine derivatives were attributed to specific hydrogen‐bonded complexes formed in the mixtures. The interpretation of experimental results is supported by density functional calculations on optimized geometries and vibrational wavenumbers of 2Br‐p and 3Br‐p and a series of hydrogen‐bonded complexes with methanol. The parameters obtained from these calculations were used for a qualitative explanation of the blue/red shifts. The wavenumber shifts and linewidth changes for the ν(CBr) stretching and trigonal bending modes as a function of concentration reveal that the caging effects leading to motional narrowing and diffusion‐causing line broadening are simultaneously operative, in addition to the blue shift caused due to hydrogen bonding. Copyright © 2007 John Wiley & Sons, Ltd.
Variable echo time imaging: Signal characteristics of 1‐M gadobutrol contrast agent at 1.5 and 3T
Authors: Stalder A.F. , Elverfeldt D. v. , Paul D. , Hennig J. , Markl M.
Published: December 2007

Gadobutrol (Gd‐Bt; Gadovist®, Schering AG) is a 1‐M Gadolinium (Gd)‐based contrast agent. Its higher Gd concentration allows for reduction of injection volumes in first pass contrast‐enhanced MR angiography (CE‐MRA) and should increase bolus sharpness and image quality. However, ambivalent results were reported. In order to explore the performance of 1‐M contrast agents such as Gd‐Bt and its dependence on molecular environment and temperature, signal characteristics were analyzed for a series of increasing Gd‐Bt concentrations for different temperature‐controlled samples in water and human blood plasma. Relaxation times, relaxivities, and signal‐concentration curves were assessed for several Gd‐Bt concentrations in water at 20°C and 37°C and in plasma at 37°C for 1.5T and 3T. Gd‐Bt concentration influence on signal intensity (SI) could be effectively simulated and compared with experimental measurements as well as simulations with other contrast agents at realistic in vivo concentrations. Particular attention was given to T2‐ and T‐induced losses at high concentrations, which annihilate benefits from T1 shortening. Based on these findings, variable echo time (VTE) approaches with readout bandwidth varying with k‐space position were explored in order to enhance the signal to noise performance of gradient echo imaging at high contrast agent concentrations. Results indicate the potential of VTE for imaging with increased SNR at high contrast agent concentrations. Magn Reson Med, 2007. © 2007 Wiley‐Liss, Inc.
Iterative projection reconstruction of time‐resolved images using highly‐constrained back‐projection (HYPR)
Authors: O'Halloran Rafael L. , Wen Zhifei , Holmes James H. , Fain Sean B.
Published: December 2007

Highly‐constrained back‐projection (HYPR) is a technique for the reconstruction of sparse, highly‐undersampled time‐resolved image data. A novel iterative HYPR (I‐HYPR) algorithm is presented and validated in computer simulations. The reconstruction method is then applied to cerebral perfusion MRI simulated as a radial acquisition and contrast‐enhanced angiography of the head to assess feasibility in accelerating acquisitions requiring high temporal resolution and accurate representation of contrast kinetics. The I‐HYPR algorithm is shown to be more robust than standard HYPR in these applications in which the sparsity condition is not met or in which quantitative information is required. Specifically, iterative reconstruction of undersampled perfusion and contrast‐enhanced angiography data improved accuracy of the representation of contrast kinetics and increased the temporal separation of arterial and venous contrast kinetics. The I‐HYPR reconstruction may have important diagnostic applications in settings requiring high temporal resolution and quantitative signal dynamics. Because I‐HYPR allows relaxation of the sparsity requirements for the composite frame, the iterative reconstruction can enable novel acquisition strategies that independently optimize the quality of the composite and temporal resolution of the dynamic frames. Magn Reson Med, 2007. © 2007 Wiley‐Liss, Inc.
Unsupervised estimation of myocardial displacement from tagged MR sequences using nonrigid registration
Authors: Ledesma‐Carbayo Maria J. , Derbyshire J. Andrew , Sampath Smita , Santos Andrés , Desco Manuel , McVeigh Elliot R.
Published: December 2007

We propose a fully automatic cardiac motion estimation technique that uses nonrigid registration between temporally adjacent images to compute the myocardial displacement field from tagged MR sequences using as inputs (sources) both horizontally and vertically tagged images. We present a new multisource nonrigid registration algorithm employing a semilocal deformation model that provides controlled smoothness. The method requires no segmentation. We apply a multiresolution optimization strategy for better speed and robustness. The accuracy of the algorithm is assessed on experimental data (animal model) and healthy volunteer data by calculating the root mean square (RMS) difference in position between the estimated tag trajectories and manual tracings outlined by an expert. For the ∼20000 tag lines analyzed (45 slices over 20–40 time frames), the RMS difference between the automatic tag trajectories and the manually segmented tag trajectories was 0.51 pixels (0.25 mm) for the animal data and 0.49 pixels (0.49 mm) for the human volunteer data. The RMS difference in the separation between adjacent tag lines (RMS_TS) was also assessed, resulting in an RMS_TS of 0.40 pixels (0.19 mm) in the experimental data and 0.52 pixels (0.56 mm) in the volunteer data. These results confirm the subpixel accuracy achieved using the proposed methodology. Magn Reson Med 2007. © 2007 Wiley‐Liss, Inc.
Lifetime course of myasthenia gravis
Authors: Grob David , Brunner Norman , Namba Tatsuji , Pagala Murali
Published: December 2007

Between 1940 and 2000 a total of 1976 patients with myasthenia gravis (MG) were studied. Diagnosis was made by improvement in weakness after anticholinesterase medication. The historical developments in diagnosis and treatment of MG are reviewed. We analyzed the clinical course of MG as influenced by age, gender, thymectomy, thymomectomy, and the presence of antibodies to acetylcholine receptors (AChR). The clinical course of MG was significantly influenced by age and gender, and these need special attention in managing patients. The most severe level of weakness and high mortality occurred during the first 1 to 2 years of the disease, after which many patients experienced improvement. For treating MG patients the usefulness of thymectomy remains to be proven, and novel drugs need to be developed to increase the number as well as normal functioning of the AChRs and other components of the neuromuscular system. Muscle Nerve, 2007
Reconciliation of income and consumption data in poverty measurement
Authors: Bavier Richard
Published: December 2007

A recent series of papers has renewed interest in the question of whether consumption data are superior to income data for poverty measurement. Although the Census Bureau has provided researchers with an experimental series of variables that can produce a comprehensive income measure, this resource has not been fully exploited in previous analyses. When poverty is measured by a comprehensive income measure, income poverty rates and trends are similar to consumption poverty rates. Arguments that income is measured with more error than consumption at the bottom of the distribution are shown to be based upon inferior income data. © 2008 by the Association for Public Policy Analysis and Management.
The relationship between income and material hardship
Authors: Sullivan James X. , Turner Lesley , Danziger Sheldon
Published: December 2007

This paper examines the relationship between income and the extent of material hardship and explores other factors that might affect hardship. Using panel data from the Women's Employment Study, we examine the incidence of material hardship from 1997 to 2003 among current and former welfare recipients. We then consider the extent to which income is associated with hardship. We show that hardship decreases monotonically across quintiles of the income distribution for several income measures. When we measure income as the average across the 6‐year study period, a 10 percent increase in average income is associated with a 1.1 percentage point decrease in the likelihood of experiencing a hardship, a drop of about 3.4 percent. We also find that the relationship between transitory changes in income and hardship is weak. These results are consistent with findings based on a nationally representative sample of disadvantaged households from the Survey of Income and Program Participation. Our results indicate that observable factors, such as measures of mental health, are more strongly related to hardship than current income. © 2008 by the Association for Public Policy Analysis and Management.
Direct certification in the national school lunch program expands access for children
Authors: Gleason Philip
Published: December 2007

Under the policy of direct certification for free school meals, school districts use information shared by state agencies about household eligibility for means‐tested programs in the state in order to determine the potential eligibility for free meals of students enrolled in the district. This information allows districts to automatically approve students in these eligible households for free meals without requiring the household to complete the application process. This paper examines the impacts of direct certification on students' likelihood of becoming certified for free meals, using data from a national survey of school food service directors as well as statelevel administrative data on program participation. A state‐level fixed effects model is estimated to account for the possibility of selection bias. The key finding is that direct certification leads to a statistically significant increase in the number of children getting free school meals. More generally, this finding highlights a promising approach for improving access to means‐tested programs without compromising program integrity. © 2008 by the Association for Public Policy Analysis and Management.
The negative impacts of starting middle school in sixth grade
Authors: Cook Philip J. , MacCoun Robert , Muschkin Clara , Vigdor Jacob
Published: December 2007

Using administrative data on public school students in North Carolina, we find that sixth grade students attending middle schools are much more likely to be cited for discipline problems than those attending elementary school. That difference remains after adjusting for the socioeconomic and demographic characteristics of the students and their schools. Furthermore, the higher infraction rates recorded by sixth graders who are placed in middle school persist at least through ninth grade. An analysis of end‐of‐grade test scores provides complementary findings. A plausible explanation is that sixth graders are at an especially impressionable age; in middle school, the exposure to older peers and the relative freedom from supervision have deleterious consequences. These findings are relevant to the current debate over the best school configuration for incorporating the middle grades. Based on our results, we suggest that there is a strong argument for separating sixth graders from older adolescents. © 2008 by the Association for Public Policy Analysis and Management.
An effectiveness‐based evaluation of five state pre‐kindergarten programs
Authors: Wong Vivian C. , Cook Thomas D. , Barnett W. Steven , Jung Kwanghee
Published: December 2007

Since 1980, the number of state pre‐kindergarten (pre‐K) programs has more than doubled, with 38 states enrolling more than one million children in 2006 alone. This study evaluates how five state pre‐K programs affected children's receptive vocabulary, math, and print awareness skills. Taking advantage of states' strict enrollment policies determined by a child's date of birth, a regression‐discontinuity design was used to estimate effects in Michigan, New Jersey, Oklahoma, South Carolina, and West Virginia. For receptive vocabulary, only New Jersey and Oklahoma yielded significant standardized impacts, though two of the three other coefficients were in a direction indicating positive effects. For math, all the coefficients were positive but only Michigan and New Jersey yielded reliable results. The largest impacts were for print awareness, where all five coefficients were positive and four were reliable in Michigan, New Jersey, South Carolina, and West Virginia. The five states were not randomly selected and, on average, have higher quality program standards than non‐studied states, precluding formal extrapolation to the nation at large. However, our sample of states differed in many other ways, permitting the conclusion that state pre‐K programs can have positive effects on children's cognitive skills, though the magnitude of these effects varies by state and outcome. © 2008 by the Association for Public Policy Analysis and Management.
Mental health and substance abuse insurance parity for federal employees: How did health plans respond?
Authors: Barry Colleen L. , Ridgely M. Susan
Published: December 2007

A fundamental concern with competitive health insurance markets is that they will not supply efficient levels of coverage for treatment of costly, chronic, and predictable illnesses, such as mental illness. Since the inception of employer‐based health insurance, coverage for mental health services has been offered on a more limited basis than coverage for general medical services. While mental health advocates view insurance limits as evidence of discrimination, adverse selection and moral hazard can also explain these differences in coverage. The intent of parity regulation is to equalize private insurance coverage for mental and physical illness (an equity concern) and to eliminate wasteful forms of competition due to adverse selection (an efficiency concern). In 2001, a presidential directive requiring comprehensive parity was implemented in the Federal Employees Health Benefits (FEHB) Program. In this study, we examine how health plans responded to the parity directive. Results show that in comparison with a set of unaffected health plans, federal employee plans were significantly more likely to augment managed care through contracts with managed behavioral health “carve‐out” firms after parity. This finding helps to explain the absence of an effect of the FEHB Program directive on total spending, and is relevant to the policy debate in Congress over federal parity. © 2008 by the Association for Public Policy Analysis and Management
Synthesis and characterization of surface‐initiated polymer brushes on silicon substrates by reversible addition fragmentation chain transfer polymerization
Authors: Wang Li‐Ping , Wang Yun‐Pu , Yuan Kun , Lei Zi‐Qiang
Published: December 2007

Polymer brushes were prepared by using the reversible addition fragmentation chain transfer (RAFT) technique. The silicon substrates (Si (111) surface) were modified with ethyl xanthate groups which were introduced by the treatment of Si (111) surface with sodium ethyl xanthate. The polymer brushes were then prepared under RAFT conditions from the Si (111) wafer. Its “living” characteristics were determined by a series of characterizations including gel permeation chromatography (GPC), ellipsometry, and contact angle measurements. The results showed a well‐defined graft layer consisting of polymer brushes with low‐polydispersity could be prepared directly on Si (111)‐X surface (where X represents an ethyl xanthate groups). The structure of the polymer brushes was characterized and confirmed with the surface sensitive techniques such as X‐ray photoelectron spectroscopy (XPS) and scanning probe microscopy (SPM). Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and photopolymerization kinetics of benzophenone piperazine one‐component initiator
Authors: Xiao Pu , Wang Ying , Dai Mingzhi , Wu Gangqiang , Shi Suqing , Nie Jun
Published: December 2007

A one‐component type II photoinitiator (PDBP), based on 4‐hydroxybenzophenone (HBP), acryloyl chloride, and piperazine, was synthesized and its structure was confirmed by 1H‐NMR. The photopolymerization kinetics of the photoinitiator was studied by real‐time Infrared spectroscopy (FT‐IR). It indicated that PDBP was a more effective photoinitiator than that of BP/triethylamine (TEA). The rate of polymerization, final conversion increased and the induction period shortened with increase in PDBP concentration, light intensity, and amine concentration. The kinetics of photopolymerization for TPGDA incorporating PDBP in the presence of different tertiary amines as the initiating system indicated that the PDBP/TEA combination exhibited the highest polymerization rates among the PDBP/amine combinations. Copyright © 2007 John Wiley & Sons, Ltd.
Stability of β‐galactosidase immobilized on composite microspheres of artemisia seed gum and chitosan
Authors: Zhang Ji , Zhang Shengtang , Wang Yunpu , Gao Sufang
Published: December 2007

In this work, composite microspheres were prepared by using artemisia seed gum and chitosan as a source. The composite microspheres have activated aldehyde groups by using glutaraldehyde. β‐Galactosidase was covalently bound on these activated microspheres. The properties of the immobilized enzyme were investigated and compared with those of the free enzyme, for which o‐nitrophenol β‐D‐galactopyranoside (ONPG) was chosen as a substrate. The results showed that the pH and thermal stability of the immobilized β‐galactosidase were higher than those of the soluble one. Apart from these, the Michaelis constant Km was evaluated for the immobilized β‐galactosidase and the soluble enzyme. The immobilized β‐galactosidase exhibited better environmental adaptability and reusability than the soluble one. POLYM. COMPOS., 29:9–14, 2008. © 2007 Society of Plastics Engineers
Preparation of polyaniline–polypyrrole composite sub‐micro fibers via interfacial polymerization
Authors: Xing Shuangxi , Zhao Guoku , Yuan Yong
Published: December 2007

Polyaniline–polypyrrole (PANI–PPy) composite sub‐micro fibers were prepared via interfacial polymerization of aniline and pyrrole using ammonium persulfate (APS) as oxidant. Carbon tetrachloride was used as the organic solvent to dissolve the monomers and APS was dissolved in HCl aqueous solution. The reaction was carried out at the interface formed by the two above solutions. Scanning electron microscopy, Fourier transformation infrared spectra and differential thermal analysis were conducted to characterize the morphology, structure and thermostability of the resulting composites. Dodecyl benzene sulfonic acid was also used as medium to make comparison with that using HCl in the reaction system. The guidance of the formation of the PANI nanofibers at the first step and the interaction between PANI and PPy were considered as the drive forces to yield the composite sub‐micro fibers. POLYM. COMPOS., 29:22–26, 2008. © 2007 Society of Plastics Engineers
Effect of curing agent on the properties of mineral silica filled epoxy composites
Authors: Teh P.L. , Mariatti M. , Wagiman A.N.R. , Beh K.S.
Published: December 2007

Polymer materials have been used extensively as the organic substrate materials in electronic packaging industry. The mechanical, thermal, and morphology properties of the alternative low cost composites have been investigated in this article. One of the materials is epoxy resin cured by aliphatic amine, and the other is cured by aromatic amine. It was found that the physical, mechanical, and thermal properties of epoxy resins are strongly depended on the curing agents. Morphology changed differently in these two epoxy‐curing systems. Crosslink density obtained from rubbery modulus in dynamic flexural storage modulus showed aromatic amine functionality group that gives higher crosslink density and increased in physical, mechanical, and thermal properties. POLYM. COMPOS., 29:27–36, 2008. © 2007 Society of Plastics Engineers
Thermal and electrical behavior of vinylester resin matrix composites filled with fly ash particles
Authors: Ray Dipa , Banerjee Sourish , Mohanty Amar K. , Misra Manjusri
Published: December 2007

Vinylester resin matrix composites were fabricated with 30, 40, 50, and 60% fly ash loading by room temperature casting method. The composites were subjected to thermogravimetric analysis. The 30 and the 60% composites showed a faster degradation at a lower temperature, whereas, the 40 and the 50% composites showed a higher onset temperature. The activation energy was calculated following Broido's equation and was found to be lowered in all the composites compared to the unfilled resin. The residue increased in all the composites proportionately with the increase in the fly ash content. The temperature variation resistance of the unfilled resin, 30 and 60% filled composites were measured and all the samples showed semi conducting nature in 40–60°C temperature range. POLYM. COMPOS., 29:58–62, 2008. © 2007 Society of Plastics Engineers
Curing behavior of epoxy/POSS/DDS hybrid systems
Authors: Zhang Zengping , Liang Guozheng , Ren Penggang , Wang Jieliang
Published: December 2007

The curing behavior of a difunctional epoxy resin/octa(aminopropyl)silsesquioxanes hybrid resin system using 4,4′′‐diaminodiphenyl sulfone as curing agent was studied. Fourier transform infrared (FTIR) spectroscopy was used to evidence the formation of the hybrid resin and to monitor the curing process. Results showed that the reactivity of the hybrid resin system was slightly lower than that of the pristine epoxy resin. Differential scanning calorimetry was used to study the curing kinetics of the hybrid resin. The curing kinetics of the pristine and hybrid resins was analyzed by two methods: Kissinger and Flynn‐Wall‐Ozawa methods. The FTIR analysis accorded well with the results of the kinetics study. POLYM. COMPOS., 29:77–83, 2008. © 2007 Society of Plastics Engineers
Project Management Priorities and the Link with Performance Management Systems
Authors: Bryde David J. , Wright Gillian H.
Published: December 2007

This paper reports the results of a project management practices study in the U.K. social housing sector. A five-factor model of project priorities is established, comprising traditional measures of project cost, time, and quality, in combination with a need to focus on stakeholders and to develop a customer and project team orientation. This model supports and integrates previously fragmented notions of project performance measurement. The relationship between these five project management criteria and the effectiveness and use of a performance management system (PMS) is then explored, with some limited evidence found that PMS effectiveness is an antecedent to practices that focus on the customer, the project team members, and other stakeholders