bluuebunny/crossref_metadata_2025 huggingface dataset:
Speculum Opening in Transsphenoidal Surgery
Authors: Garcia Adriano S. , Rhoton Albert L.
Published: July 2006

OBJECTIVE:

To assess the extent to which the transsphenoidal speculum can be safely opened at the face of and within the sphenoid sinus without risking damage to the optic nerves in the optic canals and at the orbital apex and the nerves coursing adjacent the walls of the sphenoid sinus.

METHODS:

The distance was measured between the optic nerves at the level of the anterior wall of the sphenoid sinus and 0.5 and 1.0 cm within the sinus. In addition, the distance between the middle turbinates and the contralateral optic canals was assessed because this turbinate is the largest structure blocking access to the sphenoid sinus in the transsphenoidal approach and tends to force the speculum away from the midline and toward the optic nerve in the contralateral side of the approach.

RESULTS:

Opening the transsphenoidal speculum at the anterior wall of the sphenoid sinus beyond 2.5 centimeters carries some risk of damaging the optic nerves and this distance narrows when the speculum opening is positioned inside the sphenoid sinus. Displacement of the speculum to one side by the middle turbinate places the speculum near the contralateral optic nerve and may be associated with optic nerve injury with lesser degrees of speculum opening.

CONCLUSIONS:

Careful attention should be directed to avoiding excessive opening of the transsphenoidal speculum at the anterior face of the sphenoid or within the sphenoid sinus.
Posterior Interhemispheric Approach: Surgical Technique, Application to Vascular Lesions, and Benefits of Gravity Retraction
Authors: Chi John H. , Lawton Michael T.
Published: July 2006

OBJECTIVE:

To review an experience with the posterior interhemispheric approach applied to vascular lesions in the posterior midline, to examine the effects of patient position and gravity retraction of the occipital lobe, and to identify circumstances requiring increased exposure by sectioning the falx and tentorium.

METHODS:

During a 6.5-year period, 46 posterior interhemispheric approaches were performed to treat 28 arteriovenous malformations, 10 dural arteriovenous fistulae, seven cavernous malformations, and one posterior cerebral artery aneurysm. Twenty-three patients were positioned prone and 23 patient were positioned laterally.

RESULTS:

A standard posterior interhemispheric approach was used in 38 patients, and the occipital bitranstentorial/falcine approach was used in seven patients. A contralateral occipital transfalcine approach was used with one thalamic cavernous malformation. All lesions were resected completely and/or obliterated angiographically, with good neurological outcomes in 83% of patients and no operative mortality. Blood loss was lower, operative durations were shorter, postoperative cerebral edema was decreased, and visual outcomes were improved in patients positioned laterally.

CONCLUSION:

The posterior interhemispheric approach, without additional dural cuts, is appropriate for most vascular lesions in the posterior midline. Gravity retracts the occipital lobes when patients are positioned laterally, enhancing operative exposure and reducing morbidity. Extension of the posterior interhemispheric approach to a transtentorial or transfalcine approach is required for falcotentorial dural arteriovenous fistulae and vein of Galen arteriovenous malformations, but is not usually necessary with cavernous malformations or other arteriovenous malformations.
The Endoscopic Extended Transsphenoidal Approach for Craniopharyngiomas
Authors: Frank Giorgio , Pasquini Ernesto , Doglietto Francesco , Mazzatenta Diego , Sciarretta Vittorio , Farneti Giovanni , Calbucci Fabio
Published: July 2006

OBJECTIVE:

The endoscope has recently been applied to the supradiaphragmatic transsphenoidal approach, but only case reports dealing with different pathological features have been described. The authors present their experience with this technique in 10 patients with craniopharyngiomas.

METHODS:

A pure endoscopic endonasal technique was used. From November 1998 through May 2005, four males and six females with a craniopharyngioma, either purely supradiaphragmatic (six patients) or with a significant suprasellar component (four patients), were treated. The tumors had a mean diameter of 2.9 cm (range, 1–4 cm); four patients had a major prechiasmatic component and six had a retrochiasmatic one.

RESULTS:

Seven total, one subtotal, and two partial resections were obtained. Vision symptoms improved significantly in six out of eight patients. Endocrine function did not improve after surgery, and diabetes insipidus was the most frequent deficit, although it was transient in five out of eight patients. Cerebrospinal fluid leak was the most frequent complication and required reoperation in two patients. Postoperative obesity occurred in two patients. No recurrence has yet been documented in the total resection group. The mean follow-up period is 37 months (range, 3–75 mo).

CONCLUSION:

The endoscopic technique allows results comparable with the best microscopic series. We think that this technique increases the safety of the procedure because of improved vision. Further studies are required to better define the exact location of the tumor with respect to the arachnoidal plane, the extra-arachnoidal craniopharyngioma being the most suitable for a radical removal using a transsphenoidal supradiaphragmatic approach.
C2 Crossing Laminar Screws: Cadaveric Morphometric Analysis
Authors: Wang Michael Y.
Published: July 2006

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

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

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

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.
Removal of an Orbital Apex Hemangioma using an Endoscopic Transethmoidal Approach: Technical Note
Authors: Karaki Masayuki , Kobayashi Ryuichi , Mori Nozomu
Published: July 2006

Supplemental Digital Content is Available in the Text.
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

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

Supplemental 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

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.
Numerical Prediction of the Soot and NO Formation in a Confined Laminar Diffusion Flame without and with Air Preheat
Authors: Mandal B. K. , Sarkar A , Datta A
Published: July 2006

The effect of air preheating on the formation of pollutants such as soot and NO in laminar diffusion flame is studied numerically. Only the thermal route is considered for the NO production. A numerical model has been developed to solve for the velocity, temperature, and species and soot concentration values in a confined, coflowing, laminar methane - air diffusion flame. The model uses simplified chemical kinetics following two-step reaction and a semi-empirical model for soot formation. It is shown that even with such reduced kinetic information, it is possible to predict the flame parameters and pollutant formation with significant accuracy, if suitable model parameters are adopted. It is observed from the model prediction that the soot is formed in the rich side of the flame front, but gets oxidized subsequently. The peak soot volume fraction is found to be more than five times within the flame with a 100 K increase in air inlet temperature. NO is formed around the flame just outside the flame surface where the temperature and oxygen concentrations are high. The axial flux of NO increases from the inlet plane until it reaches a constant value, indicating no further formation of thermal NO beyond a certain height because of the drop in temperature. The NO formation increases with increasing inlet air temperature.
Combustion in Porous Media
Authors: Kamal M. M. , Mohamad A. A.
Published: July 2006

The combustion research in porous medium burners has been reviewed from the early development in 1912 up to date. A collection of documented works by different authors was classified and their specific interests were addressed. These interests included the evolution and earlier work on the excess enthalpy flame in solid porous medium burners, the analytical treatment, and experimental study of flame stability in such burners. The characterization of the porous burner performance with respect to the relevant parameters was also recorded for both numerical and experimental works. The features of innovative geometries and turbulent flow conditions were demonstrated. The extension of the porous burner operation to incorporate liquid fuel combustion was also included in the classification. Relevant comments and recommendations for future work were attached at the end of each section.
Study of Energy Recovery by Means of Porous Media Considering Gas Radiation Effect
Authors: Gandjalikhan Nassab S. A. , Fallah M
Published: July 2006

This work is an extension of the theoretical findings on the relatively new concept for radiative energy recovery system using porous media. The basic high-temperature flow system is considered, in which the hot radiating gas flows through a homogeneous porous layer. The porous layer as a grey body, in addition to convective heat exchange with the gas, can absorb, emit, and scatter thermal radiation. It is desired to have a large amount of energy changes from gas enthalpy to thermal radiation by porous medium. The two-flux radiation model is used to obtain the distribution of radiative heat flux in the porous media. The numerical solution of the coupled energy equations for the gas and porous layer in steady condition is obtained using the Runge-Kutta method. The crucial influence of gas radiation effect on the system's performance is thoroughly explored.
Oxides of Nitrogen (NOx) Emission Levels of Diesel Engines of Switch Locomotives
Authors: Bannikov M. G. , Chattha J. A.
Published: July 2006

This paper presents the results of a study that was carried out to determine the emission levels of engines of switch locomotives used in Ukraine and the compliance of the engines with existing and future standards. Test results showed that none of the engines tested fully complied with United States Environmental Protection Agency and European Union standards. An experimental investigation to evaluate some of the emission reduction technologies for oxides of nitrogen, such as optimization of operating characteristics and injection timing retardation, was also conducted.
Control Analysis of the Wind Turbine with Transmission to Split Power
Authors: Zhang T , Li W , Du Y
Published: July 2006

In this article, a wind turbine with power splitting transmission, which is realized through a three-shaft planetary gearbox, is presented. The input shaft of the transmission is driven by the rotor of the wind turbine, the output shaft is connected to the grid via the main generator (asynchronous generator), and the third shaft is driven by a control motor with variable speed. The dynamic models of the subsystems of this wind turbine, e.g. the rotor aerodynamics, the drive train dynamics, and the power generation unit dynamics, were given and linearized at an operating point. These submodels were integrated in a multi-disciplinary dynamic model, which is suitable for control syntheses to optimize the utilization of wind energy and to reduce the excessive dynamic loads. The important dynamic behaviours were investigated and the suggestions to design a suitable control system were given.
Finite-Thermal Reservoir Effects on Ecologically Optimized Closed Regenerative Joule-Brayton Power Cycles
Authors: Khaliq A
Published: July 2006

A finite-time thermodynamic analysis based on a new kind of optimization criterion has been carried out for an endoreversible and regenerative Joule-Brayton power cycle coupled with variable temperature thermal reservoirs. The optimal performance and design parameters that maximize the ecological function are investigated. In this context, the optimal temperatures of the working fluid, the optimum power output, the optimum thermal efficiency, and the optimum second-law efficiency are determined in terms of technical parameters. Results are reported for the effect of regeneration, hot-cold temperature ratio, and the number of heat transfer units in hot and cold exchangers on the optimal performance parameters. The power and efficiency at maximum ecological function are found to be less than the maximum power and Curzon-Ahlborn efficiency. Power output increases significantly with increasing hot-cold side temperature ratio. However, it slightly increased as the number of heat transfer units in the regenerator increases. The optimization of ecological function leads to the improvement in exergetic efficiency and thermal efficiency, especially for low hot-cold side temperature ratios. Moreover, the thermal efficiency at maximum ecological function is less than the average of the finite time or maximum power efficiency and reversible Carnot efficiency.
Experimental Investigation of the Knock and Combustion Characteristics of CH4, H2, CO, and Some of Their Mixtures
Authors: Li H , Karim G. A.
Published: July 2006

Experimental data obtained in a single-cylinder, variable compression ratio, spark ignition (SI), cooperative fuel research (CFR) engine when operating on CH4, H2, CO, simulated reforming product gas (2H2 + CO), and some of their mixtures are presented. The dependence of the value of some key operational and combustion variables, including the knock and lean operational limits, combustion duration, and exhaust emission on fuel composition, is investigated. The significant effect of the presence of H-bearing species such as CH4, H2, or H2O on the combustion and knock characteristics of dry CO is also highlighted. Guidelines as to the suitability of these fuels for SI engine applications are provided.
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

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

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

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

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 (>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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Area-Creep Measurements for Crystalline Monolayer of Stearic Acid on the Water Surface
Authors: Kuri Taishi , Oishi Yushi , Kajiyama Tisato
Published: July 2006

The area-creep mechanism for the crystalline monolayer of stearic acid on the water surface was discussed on the basis of area-creep measurements and transmission electron microscopic observations. The area-creep behaviors of the crystalline monolayer at a high surface pressure region (≥ 15 mN m−1) was apparently different from those at a low one (≤ 10 mN m−1). At a high surface pressure region, the area-creep behavior of the monolayer was mainly classified into the two processes in shorter and longer creep time regions with respect to around 1 × 102 s. The area strain in a short creep time region was small and increased linearly with the creep time, that might be attributed to rearrangement of molecules in the crystalline monolayer during the area-creep (molecular creep). On the other hand, the area strain in a long creep time region increased remarkably owing to collapse of the monolayer (geometrical aggregation creep). Also at a low surface pressure region, the area strain was small and became almost constant at around 1 × 104 s after the area-creep experiment started. In the case of the area-creep of the crystalline monolayer at a low surface pressure, rearrangement of molecules in the crystalline monolayer and/or filling in vacancies of molecular level in the interfacial regions among the crystalline monolayer domains were proceeded with a creep time, and then, the crystallographical regularity in the monolayer was increased owing to molecular rearrangement and/or sintering at an interfacial region among crystalline monolayer domains (molecular creep).
Mesophase Structures of Higher Alkanoyl Derivatives of 6,6′-Diamino-2,2′-bipyridine and Their Metal Complexes
Authors: Kuboki Takashi , Araki Koji , Yamada Masaki , Shiraishi Shinsaku
Published: July 2006

New Cu(II), Ni(II), Co(II), and Pd(II) complexes of higher alkanoyl derivatives of 6,6′-diamino-2,2′-bipyridine were synthesized and their mesogenic properties were investigated. The Cu(II) complexes appear to exhibit a smectic C structure in their mesophase state.
A Theoretical Study on the Electronic and Vibrational Structure of the Phenoxyl Radical
Authors: Takahashi Junko , Momose Takamasa , Shida Tadamasa
Published: July 2006

The electronic structures of the phenoxyl radical in the electronic ground and excited states are studied by ab initio MO calculations. The geometries are optimized by the CAS-MCSCF procedure with the Huzinaga–Dunning DZV basis set. The electronic excitation energies and transition dipole moments are calculated by the CI procedure. According to the result of the calculation the observed absorption bands at about 600, 400, and 300 nm are assigned as , respectively. In order to analyze the vibrational character of the absorption band at about 400 nm the force constants, the potential energy distributions, the normal modes, and the Franck–Condon integrals are calculated for the three states, . The force constants are scaled by referring to the experimental resonance Raman, Trapped Ion Photodissociation (TIP), and the matrix-isolated electronic absorption spectra. The strongest vibrational band of the TIP and the absorption spectra is assigned to the 0–0 band of the transition and the second strongest, at a higher energy of 1110 cm−1, to the 0–0 band of the transition. The theoretical vibronic absorption and Raman spectra are reproduced and compared favorably with the experimental spectra.
Determination of the Magnetic Susceptibilities of Liquids Dissolving Oxygen by the Viscometer Method and a New-Type Linear Law of Susceptibility
Authors: Sueoka Kazuo
Published: July 2006

The magnetic susceptibilities of a number of liquids dissolving oxygen have been determined by an improved viscometer method at 298.15 K and 105.3 kPa; it has been confirmed that they are nicely expressed using the Wiedemann’s additivity law, and it is found that they are perfectly linear with the volume fraction of oxygen in the atmosphere in contact with liquids: a new-type law of susceptibility. It is shown that the effects of dissolved air are not canceled out unless the susceptibility of an oxygen-free liquid is used as the reference value, even when the solubilities of oxygen in the sample and the reference liquids are equal, causing a real error to an extent as much as 1.7%.
Microstructure and Optical Absorption Spectra of Transparent Glass-Ceramics Containing LiGa5O8:Co2+
Authors: Ishihara Tsuguo , Tanaka Katsuhisa , Hirao Kazuyuki , Soga Naohiro
Published: July 2006

Transparent glass-ceramics containing LiGa5O8:Co2+ have been prepared by heat treatment of glass with a composition of 13Li2O·23Ga2O3·64SiO2·xCoO (0.1, 0.2, 0.5, 1.0) (mol%). The microstructure and the optical properties have been examined by using X-ray diffraction (XRD), transmission electron microscopy (TEM), and optical absorption measurements. XRD analyses indicated that LiGa5O8 microcrystals with a crystallite size of 5 to 10 nm precipitated in the specimens heat-treated at temperatures between 750 and 850 °C. Above 850 °C, LiGaSi2O6 crystals also precipitated. Heat treatment below 850 °C successfully yielded transparent glass-ceramics. The optical absorption spectra at room temperature indicated that the absorption band due to the 4A2 → 4T1(P) transition of Co2+ ions in tetrahedral sites showed three peaks (520, 586 and 686 nm) for the glass and three peaks (560, 597, and 646 nm) for the glass-ceramics. This difference in the spectra suggests that some Co2+ ions replaced the Ga3+ ions in tetrahedral sites of the LiGa5O8 microcrystals.
Design of High-Performance Heterogeneous Metal Catalysts for Green and Sustainable Chemistry
Authors: Kaneda Kiyotomi , Ebitani Kohki , Mizugaki Tomoo , Mori Kohsuke
Published: July 2006

This account reviews a novel approach to designing high-performance heterogeneous metal catalysts using hydroxyapatites, montmorillonites, and hydrotalcites as macroligands of active metal species for aerobic alcohol oxidations, carbon–carbon bond formations, and one-pot syntheses. The catalytic systems using the above heterogeneous catalysts offer significant benefits in achieving environmentally friendly organic syntheses aiming towards Green and Sustainable Chemistry. Furthermore, the present preparation method for the immobilization of metal species is strikingly simple and allows a strong protocol for creating various nanostructured and functionalized heterogeneous catalysts.
U1-like snRNAs lacking complementarity to canonical 5′ splice sites
Authors: Kyriakopoulou Christina , Larsson Pontus , Liu Lei , Schuster Jens , Söderbom Fredrik , Kirsebom Leif A. , Virtanen Anders
Published: July 2006

We have detected a surprising heterogeneity among human spliceosomal U1 small nuclear RNA (snRNA). Most interestingly, we have identified three U1 snRNA variants that lack complementarity to the canonical 5′ splice site (5′SS) GU dinucleotide. Furthermore, we have observed heterogeneity among the identified variant U1 snRNA genes caused by single nucleotide polymorphism (SNP). The identified snRNAs were ubiquitously expressed in a variety of human tissues representing different stages of development and displayed features of functional spliceosomal snRNAs, i.e., trimethylated cap structures, association with Sm proteins and presence in nuclear RNA–protein complexes. The unanticipated heterogeneity among spliceosomal snRNAs could contribute to the complexity of vertebrates by expanding the coding capacity of their genomes.
Supplier Performance in Vertical Alliances: The Effects of Self-Enforcing Agreements and Enforceable Contracts
Authors: Srinivasan Raji , Brush Thomas H.
Published: July 2006

The paper examines the significance of enforceability and adaptability in governing vertical alliances and their performance ramifications for suppliers. Literature on supplier relations suggests that suppliers are skeptical of close ties with their buyers (Helper 1991, Helper and Sako 1995). Such skepticism persists in spite of the fact that buyers are writing longer (enforceable) contracts with fewer suppliers. In this context, the paper develops a transaction cost economics (TCE)-based model that distinguishes between the verifiable and nonverifiable aspects of governance attributes (of safeguards, incentive intensity, and adaptability) in explaining supplier performance variations. The paper argues that the following factors prove valuable for suppliers: (1) the adaptive and collaborative orientation fostered by the original equipment manufacturer’s (OEM’s) credible commitment to the exchange and by information sharing on the part of the supplier, (2) the presence of certain nonverifiable safeguards, and (3) the incentives inherent in target pricing. These assertions have been tested using data from the home appliance industry. Results indicate that information sharing together with (1) OEM dependence and (2) target pricing does indeed enhance supplier performance. Also, results suggest that while nonverifiable safeguards can help, verifiable safeguards do not have a positive association with supplier interests. Under certain conditions then, suppliers can venture into closer relationships with buyers and benefit.
Crossing an Apparent Chasm: Bridging Mindful and Less-Mindful Perspectives on Organizational Learning
Authors: Levinthal Daniel , Rerup Claus
Published: July 2006

An important new stream of organizational research has emerged in recent years that draws on the notion of mindfulness. At the same time, there is a long-standing body of work in the organizations literature that emphasizes the role of routine-driven, or less-mindful, behavior. We attempt to connect these two seemingly disparate literatures arguing that, at a performative level, important elements of less-mindful processes are necessary elements underlying mindfulness. In particular, we note the role of established action repertories that facilitate the response to novel stimuli and how routines and established role structures enable mindfulness to be sustained across time and the span of the organization. Similarly, we note important elements of mindfulness that underlie less-mindful behavior, highlighting in particular the role of mindfulness in interpreting one’s context so as to identify what constitutes appropriate action in a given circumstance and in interpreting outcomes that form the basis for processes of reinforcement learning. Although we emphasize the complementarity between the two perspectives, we also note points of tension regarding the opportunity costs of mindfulness and the theories’ implied normative claims.
Biomass as a Source of Renewable Energy in Spain: A Case Study in Regulating Renewable Energy
Authors: Sáez Antonio José Sánchez
Published: July 2006

This paper examines how, in Andalusia, the installation of plants producing biomass or processing electricity from renewable energies could conform to the public interest actions in Article 42 of the Andalusian Town Planning Act; and how the Andalusian Draft of Renewable Energies and Saving and Energy Efficiency proposes working out territorial plans for renewable energies for specific areas, where those zones enjoying the best conditions for the usage of these energies will be defined, specifying in each case the preferred renewable energy sources and their potential.