bluuebunny/crossref_metadata_2025_split huggingface dataset:
C2 Crossing Laminar Screws: Cadaveric Morphometric Analysis
Authors: Wang Michael Y. 
Published: July 2006

Abstract

OBJECTIVE:
C2 screw fixation through the pars or pedicle involves a small but finite risk of vertebral artery injury. Recently, C2 crossing laminar screws were described as a method for rigid fixation of the axis. This technique, confined to the dorsal aspect of C2, presents minimal chance of injury to the neighboring neural or vascular structures.

METHODS:
Morphometric analysis was performed on 38 cadaveric spines obtained from the Keck School of Medicine at the University of Southern California. Critical measurements were determined for screw entry points, trajectories, and lengths for application of the technique, as described by Wright, using 3.5 and 4.0 mm screws.

RESULTS:
The average maximal screw length was 32 mm with a range of 27 to 37 mm. The minimal total laminar cross sectional area averaged 75 mm2, and the cancellous bone cross sectional area averaged 39 mm2. The minimal laminar cross sectional diameter was determined to be too small to accommodate a 3.5-mm diameter screw, assuming a 1 mm tolerance on each side, in 16 sides of 14 specimens, and to be too small to accommodate a 4.0 mm diameter screw, assuming a 1 millimeter tolerance, in 32 sides of 18 specimens.

CONCLUSION:
C2 laminar screw placement is straightforward and carries little risk of injury to the neural and vascular structures as long as the implants remain intraosseous. However, the highly variable thickness of the C2 lamina necessitates preoperative computed tomographic scanning to ensure that the patient's anatomy can accommodate screws entirely within the bone.
The Endoscopic Transnasal Transsphenoidal Approach for the Treatment of Cranial Base Chordomas and Chondrosarcomas
Authors: Frank Giorgio , Sciarretta Vittorio , Calbucci Fabio , Farneti Giovanni , Mazzatenta Diego , Pasquini Ernesto 
Published: July 2006

Abstract

OBJECTIVE:
We report our experience with endoscopic transsphenoidal or extended endoscopic transsphenoidal approaches for the treatment of cranial base lesions such as clival chordomas and chondrosarcomas.

METHODS:
Between May 1998 and April 2004, 11 patients (four were recurrences because they previously had been treated with surgery and/or radiotherapy) underwent transnasal transsphenoidal endoscopic surgery for cranial base chordomas and chondrosarcomas at the Neurosurgical Department of Bellaria Hospital in Bologna. The transsphenoidal endoscopic approach and the ethmoid-pterygo-sphenoidal endoscopic approach were used to accomplish resection of the lesions involving the clivus and extending up to the parasellar region and to the petrous apex, or within the cavernous sinus.

RESULTS:
Patient follow-up periods ranged from 15 to 69 months (mean, 27 mo). Three patients died of chordoma progression at 20, 14, and 10 months, respectively, after endoscopic treatment. One patient experienced two recurrences; the first was treated using a new endoscopic approach, whereas the second, 1 year later, was treated by means of a far lateral approach. Four patients underwent postoperative proton beam radiotherapy, whereas one underwent a conventional megavoltage x-radiation therapy. However, postoperative radiotherapy was not administered in the two patients treated for cranial base chondrosarcoma.

CONCLUSION:
The flexibility of this new technique with respect to the classical microscopic transsphenoidal approach permits us to widen the horizon of surgical management of aggressive cranial base tumors such as clival chordomas and chondrosarcomas.
Three-dimensional Computed Tomographic Analysis of the Relationship Between the Arcuate Eminence and the Superior Semicircular Canal
Authors: Bulsara Ketan R. , Leveque Jean-Christophe , Gray Linda , Fukushima Takanori , Friedman Allan H. , Villavicencio Alan T. 
Published: July 2006

Abstract

OBJECTIVE:
The location of the superior semicircular canal (SSC) is often determined intraoperatively based on its topographic association with the arcuate eminence (AE). This determination is not always possible because of the potential variability in the relationship between these two structures. The goal of this study was to describe the three-dimensional (3-D) relationship between the AE and SSC using 3-D computed tomography (CT) and to evaluate the utility of 3-D CT for preoperative planning for surgical approaches to the middle cranial fossa.

METHODS:
We studied 11 patients (22 sides) radiographically using 0.8- to 1-mm thick reconstructed CT images. A standard set of structural relationships was measured between the AE, SSC, and other regional landmarks.

RESULTS:
3-D CT clearly demonstrated the relationships between traditional landmarks along the petrous ridge and middle cranial fossa. The relationship between the arcuate eminence and SSC was found to be highly variable. The average distance between the tips of the two structures was found to be 5.7 mm (range, 2.7–10.4 mm).

CONCLUSIONS:
There is significant variability in the relationship between the AE and the SSC. The AE is not a consistent or reliable landmark for identifying the precise position of the SSC. Detailed preoperative information regarding the relationship between the AE, SSC, and other bony landmarks can be easily and quickly assessed using 3-D CT.
Accuracy of Pedicle Screw Placement for Lumbar Fusion using Anatomic Landmarks versus Open Laminectomy: A Comparison of Two Surgical Techniques in Cadaveric Specimens
Authors: Karim Aftab , Mukherjee Debi , Gonzalez-Cruz Jorge , Ogden Alan , Smith Donald , Nanda Anil 
Published: July 2006

Abstract

OBJECTIVE:
We determined whether the accuracy of lumbar pedicle screw placement is optimized by performing a laminectomy before screw placement with screw entry point and trajectory being guided by pedicle visualization and palpation (Technique 1). This technique was compared with a technique using anatomic landmarks for pedicle screw placement (Technique 2). The biomechanical stability of the instrumented constructs, in the absence and presence of a laminectomy, was also compared.

METHODS:
Twelve L1–L3 specimens were harvested from fresh cadavers. The intact laminectomy and instrumented spines were biomechanically tested in flexion and extension, lateral bending, and axial rotation. Laminectomies were performed in six of the 12 specimens before pedicle screw placement using Technique 1. The remaining six specimens underwent pedicle screw and rod fixation using Technique 2. Computed tomographic images were obtained for all instrumented specimens. Deviation of the screws from the ideal entry point or trajectory was analyzed to quantitatively compare the two techniques.

RESULTS:
Computed tomographic analysis of the specimens showed that all screw placements were within the pedicles. Scatter plot analysis demonstrated that screws placed using Technique 2 were more likely to have the combination of entry points and trajectories medial to the ideal entry point and trajectory. Laminectomy did not weaken the final pedicle screw and rod-fixated constructs.

CONCLUSION:
All screw placements were grossly within the confines of the pedicles, regardless of technique, as evidenced by computed tomographic analysis. Furthermore, the anatomic landmark technique and the open laminectomy technique yielded biomechanically equivalent pedicle screw and rod-fixated constructs.
Treatment of a Partially Thrombosed Giant Aneurysm of the Vertebral Artery by Aneurysm Trapping and Direct Vertebral Artery-posterior Inferior Cerebellar Artery End-to-end Anastomosis: Technical Case Report
Authors: Benes Ludwig , Kappus Christoph , Sure Ulrich , Bertalanffy Helmut 
Published: July 2006

Abstract
Supplemental Digital Content is Available in the Text.
Preserving the Ligamentum Flavum in Lumbar Discectomy: A New Technique that Prevents Scar Tissue Formation in the First 6 Months Postsurgery
Authors: Ozer Ali F. , Oktenoglu Tunc , Sasani Mehdi , Bozkus Hakan , Canbulat Nazan , Karaarslan Ercan , Sungurlu Suleyman F. , Sarioglu Ali C. 
Published: July 2006

AbstractSupplemental Digital Content is Available in the Text.
Treatment of a Superior Sagittal Sinus Dural Arteriovenous Fistula with Onyx: Technical Case Report
Authors: Arat Anil , Inci Servet 
Published: July 2006

Abstract

OBJECTIVE:
The endovascular treatment of a complex superior sagittal sinus dural arteriovenous fistula with ethylene vinyl alcohol copolymer (Onyx) in one session is described.

CLINICAL PRESENTATION:
A 54-year-old man presented with dizziness and a bruit. A cerebral angiogram demonstrated a superior sagittal sinus dural arteriovenous fistula with a patent superior sagittal sinus that was supplied via multiple branches of the external carotid arteries bilaterally and the left anterior and middle cerebral arteries. Drainage was mainly through the superior sagittal sinus and, only in part, retrogradely through the cortical veins. A decision was made to proceed with endovascular treatment followed by surgery.

INTERVENTION:
Transarterial injection of one pedicle of middle meningeal artery on both sides with Onyx resulted in complete obliteration of the dural supply and some of the pial supply to the malformation without complications. The superior sagittal sinus remained patent. Based on this result, surgical treatment was cancelled. The residual pial supply had disappeared by the 10-month angiographic follow-up examination and the patient remained neurologically intact and without symptoms.

CONCLUSION:
Definitive treatment may be attained with Onyx in dural arteriovenous fistulas. The potential of Onyx for use as a permanent embolic agent in dural arteriovenous fistulae needs to be investigated.
Solvent Extraction of Lanthanoids(III) and Yttrium(III) with N-(2,2-Dimethylvaleryl)-N-phenylhydroxylamine
Authors: Saitoh Tohru , Okuyama Manabu , Kamidate Tamio , Watanabe Hiroto , Haraguchi Kensaku 
Published: July 2006

Abstract
Lanthanoids(III) and yttrium(III) were extracted with N-(2,2-dimethylvaleryl)-N-phenylhydroxylamine (DV-PHA) having a tertiary alkyl group attached to the carbonyl group. The distribution ratio of a lanthanoid(III) ion between the carbon tetrachloride and the aqueous phases was measured as functions of the pH and DV-PHA concentration at 298 K and an ionic strength of 0.1 (NaNO3). The aqueous phase involved sodium tartrate (1.0 × 10−2 mol dm−3). Lanthanoids(III) were extracted as a self-adducted chelate, ML3(HL)3, with DV-PHA (HL). The separation factors for pairs of Yb/Eu and Yb/Y were considerably greater than those of bis(2-ethylhexyl)hydrogenphosphate. The excellent selectivity of DV-PHA was attributable to a greater inductive effect of the tertiary alkyl group than those of the primary and secondary alkyl groups.
The Synthesis and Thermal Behavior of Hydrated Sodium Tetra-μ-imido-cyclo-tetraphosphate
Authors: Sakurai Makoto , Watanabe Makoto 
Published: July 2006

Abstract
Hydrated tetrasodium tetra-μ-imido-cyclo-tetraphosphate, (NaPO2NH)4·2.5H2O, has been prepared by hydrolyzing 2,2,4,4,6,6,8,8-octachloro-2λ5,4λ5,6λ5,8λ5-cyclotetraphosphaza-1,3,5,7-tetraene in an aqueous sodium acetate solution. The tetra-μ-imino-cyclo-tetraphosphate reorganized to produce trisodium tri-μ-imido-cyclo-triphosphate and then changed to make chain and ring condensed phosphates containing imino groups upon heating above 180 °C in air according to the following reactions:

All kinds of the imidopolyphosphates were finally converted to sodium cyclo-triphosphate above 550 °C by the substitution of imino groups for bridging oxygens and reorganization of the thermal products.
Hydrogen-Bond Detection in Peptides by 1H-Nuclear Magnetic Resonance through a Hydrogen–Chlorine Exchange Reaction
Authors: Kondo Michio , Okamoto Kouji , Nishi Ichiro , Yamamoto Makoto , Jelokhani-Niaraki Masood , Kodama Hiroaki 
Published: July 2006

Abstract
NMR spectroscopy is a versatile method for the conformational analysis of peptides and proteins. The hydrogen–chlorine exchange of amide NH protons is detected by 1H NMR and used as a method to distinguish between intramolecularly hydrogen-bonded and solvent-exposed NH moieties. The method has been applied to hydrogen bond detection in naturally occurring antibiotic peptides, such as gramicidin S, and CH3CONH–X (X = alkyl- or aryl-) derivatives. The deuterium exchange method was compared with this method in parallel experiments. In the case of chlorine exchange, in contrast to deuterium exchange, the hydrogen-bonded amide protons are replaced much faster than their solvent-exposed counterparts and the duration of the experiments is considerably less. It is highly possible that the hydrogen–chlorine exchange reaction under the present experimental conditions, in the dark and at room temperature, proceeds through an electrophilic polar mechanism.
Measurements of Superoxide Anion Radical and Superoxide Anion Scavenging Activity by Electron Spin Resonance Spectroscopy Coupled with DMPO Spin Trapping
Authors: Kohno Masahiro , Mizuta Yukio , Kusai Masako , Masumizu Toshiki , Makino Keisuke 
Published: July 2006

Abstract
A quantitative analysis of superoxide anion radical (·O2−) and hydroperoxyl radical (·OOH) generated in the hypoxanthine–xanthine oxidase (HPX–XOD) reaction system in the presence of dimethyl sulfoxide (DMSO) was explored by a spin-trapping method using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) combined with electron spin resonance spectroscopy (ESR). ·O2− and/or ·OOH was detected by ESR spectra of the spin adduct, DMPO–O2− (or DMPO–OOH). The concentration of DMPO–O2− was increased up to three times by the addition of DMSO. The half-life of DMPO–O2−, which is the time period to reduce to one-half of the initial intensity, also became about 70 times longer than that in the system without DMSO. These results suggest that the short half-life of DMPO–O2− that has been reported is attributable to the partial reaction of hydroxyl radical (·OH) with DMPO–O2−. Consequently quantitative analysis of ·O2− was possible in the presence of DMSO (&gt;0.35 M). Under these conditions, kinetic approaches show that the generation of ·O2− in the HPX-XOD reaction is a first-order reaction and that its rate constant is 6.9 × 10−8 M s−1. Finally, the competitive reaction of DMPO and SOD toward ·O2− was shown to be one unit of superoxide dismutase (Cu/Zn– SOD) scavenging ·O2− by the rate constant of 7.0 × 10−6 M min−1. This method, which can be used for measurement of SOD-like and SOD-minic activity, should be called the superoxide anion scavenging activity method.
Oxidative Deoximation with Sodium Hypochlorite
Authors: Khurana Jitender Mohan , Ray Abhijit , Sahoo Prabhat Kumar 
Published: July 2006

Abstract
A simple and convenient procedure for the deoximation with 0.5 M aqueous hypochlorite at ambient temperature is reported. Ketoximes yielded ketones quantitatively and aldoximes yielded aldehydes only at pH 5—7 or mixture of aldehydes and carboxylic acids at pH 10—11.
Synthesis and Mercurophilic Properties of Dicyanoheptafulvene-Incorporated Dithio-Crown-Ethers from Malononitrile and 5,8,11,14,17-Pentaoxa-2,20-dithiabicyclo[19.4.1]hexacosa-21,23,25-trien-26-one and Its Homologues
Authors: Mori Akira , Kubo Kanji , Takeshita Hitoshi 
Published: July 2006

Abstract
5,8,11,14,17-Pentaoxa-2,20-dithiabicylco[19.4.1]hexacosa-21,23,25-trien-26-one and its homologues gave, via remote substitution, 8,8-dicyanoheptafulvene-incorporated dithio-crown-ether derivatives upon heating with malononitrile in acetic anhydride. This means that 7-acetoxy-7-dicyanomethyl-1,3,5-cycloheptatrienes, ipso-attacked intermediates of malononitrile to acetoxytropylium derivatives, were not formed on a steric ground. These dithio-crown-ethers efficiently extract and reversibly transport mercury(II) ion.
Thermolysis of Aryl Azidomethyl Ketone N-Methyl-N-phenylsufonylhydrazones
Authors: Ito Suketaka , Kakehi Akikazu , Tabata Keiichi 
Published: July 2006

Abstract
Thermolysis of aryl azidometyl ketone N-methyl-N-phenylsulfonylhydrazones gave aryl 4-aryl-2-imidazolyl ketone N-methyl-N-phenylsulfonylhydrazones and arylglyoxal bis(N-methyl-N-phenylsulfonylhydrazone)s, the formation of which can be interpreted in terms of the insertion of nitrene into the α-methylene C–H bond of the original azidomethyl ketone hydrazones and the formation of an azo intermediate from the nitrene precursor, respectively. The sturctures of these products have been confirmed by an X-ray diffraction method.
Enantioselective Preparation of 1,3-Cyclohexadiene and 1,4-Cycloheptadiene Derivatives: Synthesis of (+)-Dictyopterene C′
Authors: Asaoka Morio , Kobayashi Katsuhiro , Takei Hisashi 
Published: July 2006

Abstract
Starting from optically active 5-trimethylsilyl-2-cyclohexen-1-one derivatives, the title dienes were synthesized by using silicon-mediated 1,4-elimination as a key step. A straightforward synthesis of the unnatural enantiomer of (−)-dictyopterene C′ utilizing the method was also carried out.
Regioselective Alkylation of (η6-Triisopropylsilylbenzene)chromium(0) Complex with Organolithium Compounds
Authors: Narasaka Koichi , Sakurai Hidehiro , Liu Changqing 
Published: July 2006

Abstract
Reactions of tricarbonyl(η6-triisopropylsilyl(TIPS)benzene)chromium(0) complex 1b with various alkyllithiums proceed regioselectively, giving para-substituted TIPSbenzenes in high yield after oxidation with iodine. Vinyllithiums also react with the TIPSbenzenechromium complex to give para-TIPSstyrenes in good yield. In the reaction with phenyllithium, although the para-substituted product is obtained as a main product, deprotonation of the aryl group of the chromium complex also occurs competitively to afford bisTIPSbiphenyls as a by-product. Alkynyllithium, however, attacks the TIPS group to yield alkynylsilane and TIPSbiphenyl.
Dynamic NMR as a Nondestructive Method for Determination of Rates of Dissociation. XXI. Dissociation in 1-(1-Haloethyl)pyrrolium Cations
Authors: Sigalov Mark V , Toyota Shinji , Oki Michinori , Trofimov Boris A 
Published: July 2006

Abstract
Topomerization observed for the isopropyl-methyls in the title compounds was reinvestigated with use of the total line shape analysis of NMR spectra. It was found that deprotonation from the pyrrolium cation preceded and was an independent step from the topomerization but the former strongly affects kinetic parameters for the latter process in the presence of excessive hydrogen halide. The extent of the excessiveness of hydrogen halide in the system also affects the reaction rates and the effects were discussed on the standpoint of activation parameters. The rates of topomerization of the isopropyl-methyls were found to be identical with the rates of enantiomerization at the 1-substituent in 1-(1-bromopropyl)-3-isopropyl-2-phenylpyrrolium ion to suggest that the topomerization in other compounds was also attributed to the ionization at the 1-substituent. The results suggest that a 1-pyrrolyl group assists ionization of 1-pyrrolylmethyl halide more effectively than a phenyl group in benzyl halide. This was reproduced by ab initio calculations.
Cobalt(III) Complexes with Quadridentate Ligands. XIII. The Preparation and Properties of cis-α, cis-β1, and cis-β2-Isomers ofthe (2-Oxidephenylacetato)(triethylenetetramine)cobalt(III) Complex
Authors: Sekizaki Haruo , Chinen Chisako , Toyota Eiko , Yamamoto Yoshihisa 
Published: July 2006

Abstract
The cis-α, cis-β1, and cis-β2-isomers of (2-oxidephenylacetato)(triethylenetetramine)cobalt(III) chloride hydrate, [Co(opa)(trien)]Cl·nH2O (opa = 2–oxidephenylacetato, trien = triethylenetetramine), have been prepared and characterized by means of analytical and spectroscopic methods. The cis-α and cis-β1-isomers of this complex were more stable than those of the salicylato- or thiosalicylato(triethylenetetramine)cobalt(III) complexes in basic aqueous solution.
Enzymatic Preparation of Enantiomerically Pure (1R,2R)- and (1S,2S)-2-Aminocyclohexanols
Authors: Takada Hironao , Takagi Seiji , Kawakubo Hiromu 
Published: July 2006

Abstract
The Pseudomonas cepacia lipase-catalyzed enantioselective hydrolysis of trans-2-(t-butoxycarbonyl)-aminocyclohexyl acetate was readily accomplished to provide a practical method for the industrial preparation of enantiomerically pure (1R,2R)- and (1S,2S)-2-aminocyclohexanols.
Facile Formation of trans-Cyclohexanediols by the Aerobic Oxidation of Cyclohexenes with Sodium Disulfite
Authors: Kimbara Nagashige , Izumi Shunsuke , Hirata Toshifumi 
Published: July 2006

Abstract
Disulfite was found to be an excellent oxidizing reagent for a gentle and stereoselective reaction to produce trans-diols via corresponding epoxides from the cyclohexenes, such as 1-p-menthen-8-yl acetate, 1,8-p-menthadiene, and 2-pinene.
Molecular Complexes of Quinolines with Iodine
Authors: Boraei Ahmed Abdel-Azim Ahmed , Abd Alla Elham Mohamed , Mahmoud Mohamed Rafat 
Published: July 2006

Abstract
1 : 1 Charge-transfer molecular complexes of some quinolines with iodine as a σ-electron acceptor were synthesized and charcterized. The spectral characteristics and stability of the formed charge-transfer comlexes were determined and are discussed in terms of the basicity and molecular structure of the donor as well as the solvent polarity. It is deduced that such factors as the n-donor strength, steric effect, and solvent polarity play operative roles in determining the stability of these CT complexes. The formed complexes are ascertained to be of a strong n–σ kind.
Crystal Structures of Highly Conducting Iodine Complexes of TTM-TTP
Authors: Mori Takehiko , Inokuchi Hiroo , Misaki Yohji , Yamabe Tokio , Mori Hatsumi , Tanaka Shoji 
Published: July 2006

Abstract
Methylthio substituted bis-fused tetrathiafulvalene, TTM-TTP (2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiaphentalene) makes three phases of iodine complexes: (TTM-TTP)I3, α-(TTM-TTP)2I3, and β-(TTM-TTP)2I3. The 1 : 1 complex exhibits high conductivity, 700 S cm−1 at room temperature, and is metallic down to about TMI = 160 K. This complex has uniform columns of the donor molecules. In the semiconducting α-(TTM-TTP)2I3, one quarter of the donors is incorporated in the anion sheet, and the sides of the other trimeric donors are blocked by the anion sheets. β-(TTM-TTP)2I3 shows metallic conductivity down to TMI = 20 K.
A 1H and 13C NMR Study of Some A3A′3 Spin Molecules Partially Oriented in a Nematic Phase
Authors: Saito Koji , Hattori Emi , Nozaki Munekazu , Yoshino Akihiro , Takahashi Kensuke 
Published: July 2006

Abstract
The 1H and 13C NMR spectra of some A3A′3 spin molecules dissolved in a nematic phase of EBBA were analyzed. The relative internuclear distances, orientation parameters, and internal motions about the symmetry axes of two methyl groups were obtained and are discussed.
Organic Second-Order Nonlinear Optical Materials with Transparency in the Blue Wavelength Region: Ethylene Derivatives Possessing Electron-Donor and Acceptor Groups
Authors: Osaka Hiroto , Ishida Takayuki , Nogami Takashi , Yamazaki Ritsuko , Yasui Masanori , Iwasaki Fujiko , Mizoguchi Akira , Kubata Michiru , Uemiya Takafumi , Nishimura Akira 
Published: July 2006

Abstract
A series of ethylene and methanimine derivatives possessing both electron-donor and -acceptor groups were synthesized in order to obtain frequency doublers of infrared semiconductor lasers. Their second-harmonic-generation (SHG) was investigated by means of a powder method and an electric-field-induced second-harmonic method. Three ethylene derivatives were found to be SHG active without any absorption in the blue wavelength region. X-Ray crystallographic analyses were made for two of them. It was found that strong donor and acceptor substituents tend to twist the central C=C double bond, thereby resulting in smaller β-values than those expected for non-twisted molecular structures. Based on the molecular and crystal structures, some strategies are presented regarding the synthesis of SHG materials of these push-pull ethylenes and methanimines.