bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas‐Phase Reactions of Homo‐ and Heteronuclear Clusters MM′+ (M, M′=Fe, Co, Ni) with Linear Alkanenitriles
Authors: Schlangen Maria , Schröder Detlef , Schwarz Helmut 
Published: June 2005

AbstractFourier‐transform ion‐cyclotron‐resonance mass spectrometry is used to investigate the reactions of mass‐selected homo‐ and heteronuclear clusters MM′+ (M, M′=Fe, Co, Ni) with linear alkanenitriles. The reactions with pentanenitrile are examined in detail by means of deuterium‐labeling studies. In comparison to the previously studied atomic cations Fe+, Co+, and Ni+, the diatomic cluster cations react more specifically and only insert in CH bonds in the initial step, whereas the bare ions M+ activate both CH and CC bonds. Like for the atomic cations, dehydrogenation proceeds via remote functionalization of the terminal positions of the substrate, although H‐scrambling processes, preceding dehydrogenation, are more pronounced for the dinuclear cluster cations. The Ni‐containing cluster cations CoNi+ and Ni$\rm{_{2}^{+}}$ are unique in that they bring about double dehydrogenation as well as activation of CC bonds subsequently to the first dehydrogenation. The latter kind of reaction is also partly observed for the [RCN−H2]‐complexes of FeCo+, Co$\rm{_{2}^{+}}$, and FeNi+ in their secondary reactions with pentanenitrile. The behavior of the Fe‐containing cluster cations Fe$\rm{_{2}^{+}}$ and FeCo+ is more subtle compared to that of the Ni‐containing clusters Ni$\rm{_{2}^{+}}$ and CoNi+ as well as that of homonuclear Co$\rm{_{2}^{+}}$. Based on extensive labeling experiments, dehydrogenation of pentanenitrile by these cluster cations follows a 1,2‐elimination mode, whereas loss of H2 from the Fe$\rm{_{2}^{+}}$ and FeCo+ complexes of the substrate proceeds to some extent via a 1,1‐elimination involving the unactivated Me group of the substrate. A more quantitative description of the labeling distribution has been achieved by extensive modeling.
The Chemistry of the Thiosulfinyl Group: Preparation, Structure, and Spectroscopic and Chemical Properties of Cyclic Thionosulfites
Authors: Nakayama Juzo , Yoshida (nee Tanaka) Sanae , Sugihara Yoshiaki , Sakamoto Akira 
Published: June 2005

AbstractTreatment of the tetrahydrothiophene‐3,4‐diol 5 with 1,1′‐thiobis‐(1H‐benzimidazole) (6) furnished two diastereoisomers of the novel cyclic thionosulfite 4 with different configurations at the pseudo‐tetrahedral center of the thiosulfinyl (SS) group. The configuration of the SS group of the major diastereoisomer (isolated in 45% yield) was established to be syn to the thiolane ring, as determined by X‐ray crystallographic analysis, while that of the minor diastereoisomer (isolated in 10% yield) was anti. 1H‐NMR Spectroscopic analysis clarified that the shielding and deshielding zones of the SS group are similar to those of the well‐documented SO group. Characteristic absorptions of the SS group in the IR, Raman, and UV/VIS spectra were assigned on the basis of calculations at the B3LYP/6‐31G* level. The reactivity of the SS group toward thermolysis, hydrolysis, and oxidation was examined. The SS group is more resistant toward oxidation than the divalent sulfide S‐atom, but is oxidatively converted to the SO group.
Vicinal Diamination of Terminal Olefins
Authors: Pfaendler Hans Rudolf , Klingl Alexander 
Published: June 2005

AbstractThe present publication describes an efficient and mild three‐step conversion of a terminal olefin 1 into the corresponding 1,2‐diamine 5. The sequence includes: azidoiodination, substitution with NaN3, and catalytic hydrogenolysis. The terminal 1,2‐diamine 5 was converted into its cis‐dichloroplatinum(II) complex 6.
Tropone Is a Mere Ketone for Cycloadditions to Ketenes
Authors: Okamoto Junko , Yamabe Shinichi , Minato Tsutomu , Hasegawa Toshio , Machiguchi Takahisa 
Published: June 2005

AbstractTropone (1) reacts with ketenes 2 to yield [8+2] cycloadducts, the γ‐lactones 3. The concerted [8+2] cycloaddition path is formally symmetry‐allowed, but we established that it is unfavorable. Careful low‐temperature NMR (1H, 13C, and 19F) spectroscopies of the reaction of diphenyl ketene (2b) or bis(trifluoromethyl) ketene (2c) with tropone (1) allowed the direct detection of a β‐lactone intermediates 5b,c and novel norcaradiene species 6b,c in head‐to‐head configurations. The [2+2] cycloadducts 5b,c equilibrated with the norcaradienes 6b,c. The β‐lactones 5b and 5c were converted to the γ‐lactones 3b and 3c, respectively, in quantitative yields. The DFT calculations showed that the concerted [8+2] cycloaddition is unfavorable. The first step of the calculated reaction 1+2c is a cycloaddition which leads to a dioxetane intermediate. This initial [2+2] cycloadduct is isomerized to the β‐lactone 5c via the first zwitterionic intermediate. The β‐lactone 5c is further isomerized to the product γ‐lactone 3c via the second zwitterion intermediate. Thus, 3c is not formed via the well‐established two‐step mechanism including zwitterionic intermediates but via a five‐step mechanism composed of a [2+2] cycloaddition and subsequent isomerization (Scheme 12).
Thermal Isomerization of 12‐Oxa‐1,9‐dimetylhexacyclo[7.2.1.02,4.02,8.03,7.06,8]dodec‐10‐ene: A Computational Mechanistic Investigation
Authors: Glück‐Walther Susanne , Szeimies Günter 
Published: June 2005

AbstractFlash‐vacuum pyrolysis of the quadricyclane derivative 5a at 350° afforded the oxabishomocubane 9a, whose structure was confirmed by an INADEQUATE‐NMR experiment. A computational investigation of the mechanism of this unexpected reaction by DFT and CASPT2‐SCF methods indicated that the reaction path of lowest energy involves a quadricyclane/oxaquadricyclane (5/12) isomerization, followed by a well‐established cycloreversion of 12 to the carbonyl ylide 16, which subsequently undergoes an intramolecular 1,3‐dipolar cycloadditon to 9. The lowest‐energy path of the thermal isomerization of the syn‐quadricyclane 6c is its conversion to the syn‐sesquinorbornatriene 8c. The corresponding anti‐isomer 5c, however, shows the capability of a degenerate quadricyclane/quadricyclane rearrangement.
Prostaglandins and reproduction in male lizard, Podarcis sicula sicula
Authors: Gobbetti Anna , Zerani Massimo , di Fiore Maria Maddalena 
Published: June 2005

AbstractThe possible role of prostaglandins in the reproductive processes of the male lizard, Podarcis sicula sicula, was investigated. The plasma levels of prostaglandin F2α (PGF2α), prostaglandin E2 (PGE2), progesterone, androgens, and 17β‐estradiol, and the in vitro basal release of these hormones by testis, epididymis and interrental, at different phases of the annual sexual cycle, were studied. In addition, the in vivo and in vitro effects of PGF2α and PGE2 on steroid production were evaluated. In in vivo experiments, PGF2α and 17β‐estradiol plasma levels were highest during the refractory phase; PGE2 values were lowest and androgens highest in fighting phase. PGF2α injection increased 17β‐estradiol in refractory phase; PGE2 increased androgens in fighting phase and 17β‐estradiol in refractory phase. In in vitro experiments, testis released the highest levels of PGF2α and 17β‐estradiol in refractory phase, and of PGE2 and androgens in fighting phase. Interrenal released the highest levels of PGF2α, PGE2, and 17β‐estradiol in refractory phase, and of androgens in fighting phase. Epididymis released the highest values of PGF2α and PGE2 in mating phase. PGF2α treatment increased 17β‐estradiol release by testis and interrenals in refractory phase. PGE2 treatment increased androgen release by testis in fighting phase and 17β‐estradiol release by interrenal in refractory phase. The present data indicate that in male lizards, P. s. sicula, testicular androgen synthesis during the fighting phase is under the control of PGE2, while 17β‐estradiol synthesis during refractory phase is regulated in the testis by PGF2α and in interrenal by PGF2α and PGE2. © 1994 Wiley‐Liss, Inc.
Cardiac CINE imaging with IDEAL water‐fat separation and steady‐state free precession
Authors: Reeder Scott B. , Markl Michael , Yu Huanzhou , Hellinger Jeffrey C. , Herfkens Robert J. , Pelc Norbert J. 
Published: June 2005

AbstractPurposeto decompose multicoil CINE steady‐state free precession (SSFP) cardiac images acquired at short echo time (TE) increments into separate water and fat images, using an iterative least‐squares “Dixon” (IDEAL) method.Materials and MethodsMulticoil CINE IDEAL‐SSFP cardiac imaging was performed in three volunteers and 15 patients at 1.5 T.ResultsMeasurements of signal‐to‐noise ratio (SNR) matched theoretical expectations and were used to optimize acquisition parameters. TE increments of 0.9–1.0 msec permitted the use of repetition times (TRs) of 5 msec or less, and provided good SNR performance of the water‐fat decomposition, while maintaining good image quality with a minimum of banding artifacts. Images from all studies were evaluated for fat separation and image quality by two experienced radiologists. Uniform fat separation and diagnostic image quality was achieved in all images from all studies. Examples from volunteers and patients are shown.ConclusionMulticoil IDEAL‐SSFP imaging can produce high quality CINE cardiac images with uniform water–fat separation, insensitive to Bo inhomogeneities. This approach provides a new method for reliable fat‐suppression in cardiac imaging. J. Magn. Reson. Imaging 2005;22:44–52. © 2005 Wiley‐Liss, Inc.
Peritumoral fat‐spared area is well correlated with the presence of temporal peritumoral enhancement in hepatic hemangioma in fatty liver
Authors: Chen Ran‐Chou , Li Chao‐Shiang , Lii Jiunn‐Ming , Chen Wei‐Tsung , Tu Hsing‐Yang 
Published: June 2005

AbstractPurposeTo assess the relationship between temporal peritumoral enhancement and peritumoral focal fat sparing adjacent to hepatic hemangiomas.Materials and MethodsOn the basis of MRI and sonographic imaging follow‐up, 51 hepatic hemangiomas were identified in 37 patients, who had both hepatic hemangiomas and focal fat‐sparing areas in fatty liver. Among them, 36 tumors were associated with peritumoral focal fat spares. The association between the temporal peritumoral enhancement in the early arterial phase of dynamic MRI and peritumoral fat sparing in the same hemangioma was investigated. Furthermore, the configuration of the temporal peritumoral enhancement was correlated with that of the peritumoral focal fat‐sparing area. We used Chi square and Fisher's exact test for statistic analysis.ResultsA total of 31 out of 36 hemangiomas (86.1%) showed both peritumoral focal fat spares and temporal peritumoral enhancement. The presence of temporal peritumoral enhancement is significantly related to that of peritumoral focal fat‐sparing (P < 0.001). A total of 21 of the 31 tumors (67.7%) presented with similar configuration of the peritumoral focal fat‐sparing area and temporal peritumoral enhancement area with respect to size and shape. The remaining 10 hemangiomas showed similar shape but slightly different size in these two imaging characteristics.ConclusionTemporal peritumoral enhancement seen in hepatic hemangioma might be related to focal fatty sparing adjacent to the hemangiomas. J. Magn. Reson. Imaging 2005;22:86–91. © 2005 Wiley‐Liss, Inc.
1H MRI of pneumococcal pneumonia in a murine model
Authors: Marzola Pasquina , Lanzoni Anna , Nicolato Elena , Di Modugno Vincenza , Cristofori Patrizia , Osculati Francesco , Sbarbati Andrea 
Published: June 2005

AbstractPurposeTo detect and quantify pulmonary lesions due to pneumococcal pneumonia in a murine model by 1H MRI.Materials and MethodsPneumonia was induced in mice (N = 5) by intranasal administration of about 1 × 106 colony‐forming units (CFU) of Streptococcus pneumonie. A group of noninfected animals (N = 5) was used as a control group. MRI was performed, 48 hours after infection induction, at 4.7 T. ECG‐gated gradient‐echo (GRE) sequences with TE = 5 msec were used. After MRI examination, the animals were sacrificed for histological examination.ResultsLungs appeared at MRI as regions with signal intensity (SI) at the level of the noise. Lesions appeared as hyperintense regions over the background and were localized mainly in the apical part of the lungs, in the medial and peribronchial regions. The anatomical localization of the lesions was confirmed by histology. The total lesion volume quantified by MRI data correlated with the total lesion volume quantified by histology.ConclusionThis work shows that standard 1H MRI allows detection and quantification of lesions due to pneumococcal pneumonia in mice. J. Magn. Reson. Imaging 2005;22:170–174. © 2005 Wiley‐Liss, Inc.
Fast and high‐resolution MR sialography using a small surface coil
Authors: Takagi Yukinori , Sumi Misa , Van Cauteren Marc , Nakamura Takashi 
Published: June 2005

AbstractPurposeTo establish a fast and high‐resolution MR sialographic technique that provides fast and high‐resolution imaging.Materials and MethodsMR sialography was performed on a 1.5‐T MR imager using a small (47‐mm) surface coil. We determined appropriate sequence parameters, and then applied the technique to the salivary glands of 143 patients with xerostomia (including those with Sjögren's syndrome or hyperlipidemia) or salivary gland inflammation. We compared the high‐resolution MR sialography with conventional x‐ray sialography in the patients with xerostomia to evaluate the effectiveness of the MR sialography technique.ResultsWe found that a single‐shot, single‐slice MR sialography (TR/TR/number of signal acquisitions [NSA] = 8000 msec/1000 msec/6) using a small surface coil provides excellent duct images that are clinically feasible with fast (imaging time of 56 seconds) and high‐resolution images. An alternative three‐dimensional MR sialography technique provided better details of the branches at the expense of imaging time. The MR sialography technique using a small surface coil depicted effectively the ductal changes in the salivary glands in patients with or without Sjögren's syndrome, reflecting the severity of the diseases.ConclusionWe conclude that MR sialography can be performed using a fast and high‐resolution sequence. J. Magn. Reson. Imaging 2005;22:29–37. © 2005 Wiley‐Liss, Inc.
Comparison of 15 different stents in superficial femoral arteries by high resolution MRI ex vivo and in vivo
Authors: Adams Gareth J. , Baltazar Ulises , Karmonik Christof , Bordelon Cassius , Lin Peter H. , Bush Ruth L. , Lumsden Alan B. , Morrisett Joel D. 
Published: June 2005

AbstractPurposeTo evaluate the MRI compatibility of 15 different commercially available, new generation, U.S. Food and Drug Administration (FDA)‐approved stents suitable for deployment in superficial femoral arteries (SFAs), and to identify the ones that permit MRI to visualize the wall and lumen of stented arteries with sufficient spatial and contrast resolution to quantify restenosis after stent placement.Materials and MethodsA total of 13 nitinol stents and two stainless‐steel stents were placed in excised cadaveric SFAs and imaged by MRI at 1.5 T ex vivo. The images were evaluated qualitatively for the presence of artifacts and for the effects of the stent on image contrast, and quantitatively for the effect on signal‐to‐noise ratio (SNR) of the lumen of the artery inside the stent compared to the SNR of the fluid outside the artery. A nitinol stent was placed in the SFA of a 60‐year‐old man and imaged at 1.5 T in vivo.ResultsBoth the vessel wall and the lumen could be visualized in cadaveric SFAs containing either the Absolute nitinol stent, the Dynalink nitinol stent, or the aSpire nitinol‐covered stent. Their inside stent/outside stent SNR was 0.7, 0.8, and 0.8, respectively. The other 10 nitinol stents tested obscured the lumen but did not cause major image shape artifacts. Both stainless‐steel stents tested, the WallGraft and WallStent, completely obscured the lumen and caused significant distortion of the image shapes. When the Dynalink stent was inserted into a highly stenosed SFA in vivo, the image showed a dark expanded eccentric lumen, circumscribed by a medium intensity band containing the stent.ConclusionMRI can be used to visualize both the lumen and wall of SFAs containing selected nitinol stents ex vivo and in vivo. These results suggest that MRI can be used to monitor restenosis in stents placed in the femoral arterial bed. J. Magn. Reson. Imaging 2005;22:125–135. © 2005 Wiley‐Liss, Inc.
Repeatability of a novel technique for in vivo measurement of three‐dimensional patellar tracking using magnetic resonance imaging
Authors: Fellows Robert A. , Hill Nick A. , MacIntyre Norma J. , Harrison Mark M. , Ellis Randy E. , Wilson David R. 
Published: June 2005

AbstractPurposeTo determine the repeatability of a novel noninvasive MRI‐based technique for measuring patellofemoral kinematics in vivo.Materials and MethodsThe patellar kinematics measurement method relies on registering bone models (with associated coordinate systems) developed from a high resolution MRI scan to loaded bone positions derived from fast, low resolution MRI scans. The intrasubject variability, high resolution to low resolution registration error, and interexperimenter repeatability were quantified in experiments on three healthy subjects.ResultsThe intrasubject variability and registration error were within range of the accuracy of our procedure; specifically, less than or equal to 1.40° for orientation and 0.81 mm for translation. The interexperimenter repeatability was less than or equal to 1.28° for orientation, with the exception of patellar spin, and 0.68 mm for translation.ConclusionOur novel measurement technique can measure three‐dimensional patellar tracking noninvasively during loaded flexion in a repeatable manner. Our results compare well to another noninvasive tracking protocol, fast phase‐contrast MRI, which has a reported subject interexam variability of 2.4° or less for patellar orientation. A particular strength of our method is that axes and high‐resolution bone models need only be determined once for intrasubject comparisons. The method is sufficiently accurate and repeatable to detect clinically significant changes in patellofemoral kinematics. J. Magn. Reson. Imaging 2005;22:145–153. © 2005 Wiley‐Liss, Inc.
Spatially‐confined arterial spin‐labeling with FAIR
Authors: Zhang Yan , Song Hee Kwon , Wang Jiongjiong , Techawiboonwong Aranee , Wehrli Felix W. 
Published: June 2005

AbstractPurposeTo investigate the effectiveness of slab‐selective inversion in pulsed arterial spin labeling with body coil excitation as a means to reduce large vessel contamination of the perfusion signal.Materials and MethodsStudies were conducted by varying the tagging width in multislice flow‐sensitive alternating inversion recovery (FAIR) in conjunction with body coil excitation on a Siemens Sonata whole‐body 1.5‐T scanner. The results of spatially‐confined tagging were then compared with conventional nonselective tagging in the presence and absence of a bipolar gradient crusher pair in order to determine the effectiveness of suppressing vascular signal and to estimate the bolus width that reaches the capillary bed.ResultsIt is shown in five volunteers, ages 23–38 years, that depending on the average velocity of the arterial blood flow in the tagging region, a bolus of 6–8 cm in width reaches the capillary bed at a fixed inversion time TI of 1.4 seconds, while a bolus of 11.2–16.5 cm in width enters the imaging region. Further, noticeable velocity differences have been found among the participating subjects, with averages ranging from 10.1 to 13.9 cm/second.ConclusionThe data suggest that it is advantageous to replace nonselective global tagging in FAIR perfusion imaging with body coil excitation by spatially‐confined tagging to reduce undesired residual tagged blood in large vessels. J. Magn. Reson. Imaging 2005;22:119–124. © 2005 Wiley‐Liss, Inc.
Cytological and cytochemical investigations on the fœtal and adult hypophysis in various physiological and pathological states
Authors: Pearse A. G. Everson 
Published: June 2005

AbstractIn two previous papers (Pearse, 1952aandb) the cytochemistry of the anterior hypophysis and its normal cytology as shown by the trichrome‐periodic acid‐Schiff method were described. The second of these dealt with the use of a primarily histochemical method by which three cell types—mucoid cells, acidophils and chromophobes—can be recognised. The first class includes all cells which contain mucoprotein in diffuse, granular or vesiculate form, and it was shown that all the basophils (cyanophils) of the older terminology and up to 30 per cent. of the chromophobes belonged to the mucoid‐cell series, all of which may reasonably be supposed to be concerned witht he production of the gonadotropic and thyrotropic (mucoprotein) hormones. The mucoid cells were divided into eight types and a differential count of 500–1000 cells was made the basis of a rapid method for estimating the amount of mucoprotein storage and production in the gland. This “Maximal‐Intermediate (M/I) count” usually considers only four or five of the eight cell types, the others being included with the second type as intermediate cells.
Oesophageal epithelial ultrastructure after incubation with gastrointestinal fluids and their components
Authors: Bateson M. C. , Hopwood D. , Milne G. , Bouchier I. A. D. 
Published: June 2005

AbstractOesophageal biopsies from endoscopically normal patients were incubated in the following for up to 30 min—Ham's F10 medium:isotonic saline:0.1 N HCl:20, 2 and 0.2 mM bile acids:trypsin: pepsin:lipase; autologous gastric and duodenal juices. The biopsies were then examined by electron microscopy. No morphological change was produced by Ham's F10 or saline. HCl caused little damage. Gastric juice produced widespread severe damage, as did pepsin. Duodenal juice and the enzymes tested caused lysis and internalisation of desmosomes and peripheral cytoplasmic vacuolation. Bile acids split desmosomes and induced microvesiculation of the cell membranes. Similar microvesiculation was also induced by duodenal juice. All media except hydrochloric acid eventually produced organelle damage and leaky and disrupted cells. The functional and superficial cells appeared to be able to withstand attack from these experimental media better than did prickle and basal cells. Membrane coating granules were secreted in the presence of hydrochloric acid, but not with enzymes.
Ultrastructural changes in spontaneous rupture of mitral chordae tendineae
Authors: Scott‐Jupp Wendy , Barnett N. L , Gallagher P. J. , Monro J. L. , Ross J. K. 
Published: June 2005

AbstractMitral valves from ten patients with spontaneous rupture of mitral chordae were examined by light, scanning and transmission electron microscopy. Changes identified at rupture sites included oedema and necrosis of collagen, endothelial loss and, in some cases, partial or complete re‐endothelialisation of the disrupted ends. With a solitary exception these abnormalities were confined to chordae which had actually ruptured. Some nonruptured chordae were irregularly thinned and stretched but were normal by light and electron microscopy. Mucoid degeneration was almost invariable in mitral valve leaflets.These results suggest that spontaneous chordal rupture is more likely to be the result of abnormal mechanical strain rather than a diffuse connective tissue abnormality affecting multiple chordae. They may also provide theoretical justification for reconstruction rather than replacement of mitral valves in this condition.