bluuebunny/crossref_metadata_2025 huggingface dataset:
Metallated 2‐Alkenyl Sulfoximines in Asymmetric Synthesis: Regio‐ and Stereoselective Synthesis of Highly Substituted Tetrahydrofurans
Authors: Reggelin Michael , Weinberger Heinz , Heinrich Timo
Published: July 2007

Starting from the enantiopure 2‐alkenyl sulfoximines 4/5 and epi‐4/5, a one‐pot procedure has been developed for the synthesis of tri‐ and tetrasubstituted tetrahydrofuran derivatives with excellent control of all relevant aspects of their structural description. The cyclization of the intermediate γ‐hydroxyvinyl sulfoximines is strictly regioselective due to the electronic properties of the double bond involved. The absolute configuration at C‐2 can be selected at will by a proper choice of the corresponding lactaldehydes 14 or ent‐14 respectively. The absolute configuration at the 3‐ and 4‐positions of the THF derivatives is under control of the sulfoximine moiety during aldehyde uptake, whereas their relative configuration is fixed due to the 1k relative topicity of attack of the reactands involved in their generation. The configuration at position 5 is determined mainly by the release of 1,3‐allylic strain and is therefore the only stereogenic centre under substrate control. This becomes obvious in two cases (17a and 18a) where stereocontrol at this position is diminished. Here, the absence of a 3‐methyl group as a control element reduces the energetic difference between the Re‐ and the Si‐side attack.
Structure‐odor correlation, XXV. Synthesis and Olfactory Properties of the “Inverse” Megastigmatrienone and Its Analogs
Authors: Weyerstahl Peter , Licha Kai
Published: July 2007

The oxoisophorone monoacetal 2 is a convenient starting material for the synthesis of several megastigmatrienone analogs. Thus, the Wittig reaction of ketone 2, followed by deprotection, led to the dienones 7–10. The “inverse” megastigmatrienone 1 was synthesized from 2 via homologation (→11→12), Grignard reaction (→13) and hydrolysis. The mixture of the four stereoisomers of 1 is dominated by (E,E)‐1. In contrast, (Z,Z)‐1 was obtained as the main product when starting from 2 and proceeding via the reaction sequence →14 →15 →16 →17 and then (Z)‐selective Wittig reaction of aldehyde 17. Likewise, ketoaldehyde 17 is the starting material for the nor derivative 20. The odor evaluation of 1 showed that the typical strong and pleasant tobacco odor of megastigmatrienone D was by no means observed, neither in strength nor in quality. On the other hand, the four stereoisomers of 1 all exhibit a similar weak to moderate odor of floral, sweet, fresh and coumarin‐like tonalities.
One‐Step Synthesis of Functionalized Triptycene‐quinones as Acceptors for Electron‐Transfer Compounds
Authors: Wiehe Arno , Senge Mathias O. , Kurreck Harry
Published: July 2007

The synthesis of appropriate porphyrin‐quinone electron‐transfer complexes as model compounds for photosynthesis requires access to functionalized triptycene quinone aldehydes with different redox potentials. A synthetic strategy involving a classical Diels‐Alder reaction, tautomerization and oxidation was only of limited utility for preparing the desired compounds. Thus, an alternative approach was required and for this purpose a strategy involving the reaction of excess quinone with appropriate anthracene derivatives in acetic acid has been developed. This method affords the target compounds in a single synthetic step in good yields and with high purity. The aldehyde functionality required for the subsequent porphyrin synthesis can be incorporated into either the anthracene or the quinone starting component. Fifteen different triptycene quinones have been synthesized, eight of which have been studied in detail by single crystal X‐ray crystallography to provide insight into their structural chemistry and solid‐state aggregation properties. Additionally, the synthesis of two porphyrin‐quinone target compounds is described.
Structural Aspects of Cyclopropyl Conjugation: Experimental Studies and Ab Initio Calculations
Authors: Haumann Thomas , Boese Roland , Kozhushkov Sergei I. , Rauch Karsten , de Meijere Armin
Published: July 2007

Low temperature crystal structural studies of small cyclopropyl‐conjugated unsaturated hydrocarbons reveal significant differences in bond lengths between carbon atoms mainly within the three‐membered rings but also for adjacent CC single bonds. The strongest influence of conjugation was observed for spiro[2.4]hepta‐4,6‐diene (1), where the difference in the lengths of three‐membered ring bonds is 0.050 Å (X‐ray). The same effect is also obvious from ab initio calculations at HF/6‐31G(d) (to a minor extent) and MP2/6‐31G(d) levels, as shown by a difference analysis of bond lengths which was performed in order to cancel out systematic errors and differences for both methods. Static difference electron density maps were derived from the experimental data by multipole refinements. These maps showed shifts of electron density to exocyclic locations within the planes of the three‐membered rings and significant bond ellipticities for the adjacent single bonds. For 1,1‐diethenylcyclopropane (4) a nonsymmetric conformation was found in the crystal lattice, very close to the global minimum structure calculated by ab initio methods.
Oxidation of 4‐Alkyl‐2′‐Hydroxy‐2‐cinnamylideneacetophenones with Thallium(III) Trinitrate: A New Synthesis of (E)‐3‐Styrylchromones
Authors: Silva Artur M. S. , Cavaleiro José A. S. , Elguero José
Published: July 2007

The oxidative rearrangement of (E,E)‐4‐alkyl‐2′‐hydroxy‐2‐cinnamylideneacetophenones 4, obtained by base‐catalysed aldol reaction of 2′‐hydroxyacetophenone and cinnamaldehydes with thallium(III) trinitrate, gave the corresponding 3‐alkyl‐4‐aryl‐1‐(2′‐hydroxyphenyl)‐2‐(dimethoxymethyl)‐3‐buten‐1‐ones. The cyclization of these acetal intermediates with hydrochloric acid gave (E)‐3‐styrylchromones 5. The stereochemistry of the 4‐alkyl‐2′‐hydroxy‐2‐cinnamylidene‐acetophenones 4 and 3‐styrylchromones 5 double bonds was established by NOE experiments.
Unexpected High Temperature Behaviour of 2,2′‐Diethynylbiphenyl in the Gas Phase – a Precursor for Acephenanthrylene Instead of Pyrene
Authors: Sarobe Martin , van Heerbeek Rieko , Jenneskens Leonardus W. , Zwikker Jan W.
Published: July 2007

Flash Vacuum Thermolysis (FVT) of 2,2′‐diethynylbiphenyl (6) gave, instead of pyrene (5), acephenanthrylene (10) and fluoranthene (11) as major products. The unequivocal identification of 9‐ethynylphenanthrene (12) at T ⩽ 800 °C suggests that 12 is the initial stable product derived from 6. It is documented that under high‐temperature conditions in the gas phase compound 12 is efficiently converted into 10, which subsequently rearranges to 11. The formation of 12 from 6 is rationalized by invoking the transient formation of cyclobuta[l]phenanthrene (13) by intramolecular cyclization of the ethynyl moieties of 6 followed by a retro‐carbene CH insertion and a 1,2‐H shift. This interpretation is supported by the results of independent FVT of 2,2′‐bis(1‐chloroethenyl)biphenyl (15).
C‐Terminal Incorporation of α‐Trifluoromethyl‐Substituted Amino Acids into Peptides via In‐Situ Deprotection of N‐Teoc Derivatives
Authors: Hollweck Wolfgang , Sewald Norbert , Michel Thomas , Burger Klaus
Published: July 2007

A new method for peptide coupling, involving α‐trifluoromethyl substituted amino acids as nucleophiles, proceeds via fluoride catalyzed in situ deprotection and coupling of N‐Teoc protected amino acid esters. A mixed anhydride is thought to be the reaction intermediate.
Synthesis of [7,7‐2H2]epibrassinolide
Authors: Khripach Vladimir A. , Khripach Natalya B. , Zhabinskii Vladimir N. , Zhiburtovich Yuliya Y. , Schneider Bernd , de Groot Aede
Published: July 2007

Synthesis of labelled epibrassinolide containing two deuterium atoms in a position which is not subjected to isotopic exchange is reported. Key transformations include preparation of 6,7‐seco steroidal diacid, its cyclization to a cyclic anhydride followed by a regioselective reduction with NaBD4. The obtained [7,7‐2H2]epibrassinolide can be used in biochemical experiments when the loss of isotopic label should be avoided. Copyright © 2007 John Wiley & Sons, Ltd.
Metastatic PEComa arising from renal angiomyolipoma: MRI findings
Authors: El Jack Amr K. , Tomaszewski John E. , Haller Daniel G. , Siegelman Evan S.
Published: July 2007

The perivascular epithelioid cell tumor (PEComa) is a neoplasm composed primarily of HMB‐45‐positive epithelioid cells with a perivascular distribution. Both benign and malignant PEComas have been reported in diverse anatomic locations. We report the MRI features of a metastatic PEComa to the liver that originated within a renal angiomyolipoma (AML). J. Magn. Reson. Imaging 2007;26:159–161. Published 2007 Wiley‐Liss, Inc.
Magnetic resonance imaging and model prediction for thermal ablation of tissue
Authors: Chen Xin , Barkauskas Kestutis J. , Nour Sherif G. , Duerk Jeffrey L. , Abdul‐Karim Fadi W. , Saidel Gerald M.
Published: July 2007

Purpose

To monitor and predict tissue temperature distributions and lesion boundaries during thermal ablation by combining MRI and thermal modeling methods.

Materials and Methods

Radiofrequency (RF) ablation was conducted in the paraspinal muscles of rabbits with MRI monitoring. A gradient‐recalled echo (GRE) sequence via a 1.5T MRI system provided tissue temperature distribution from the phase images and lesion progression from changes in magnitude images. Post‐ablation GRE estimates of lesion size were compared with post‐ablation T2‐weighted turbo‐spin‐echo (TSE) images and hematoxylin and eosin (H&E)‐stained histological slices. A three‐dimensional (3D) thermal model was used to simulate and predict tissue temperature and lesion size dynamics.

Results

The lesion area estimated from repeated GRE images remained constant during the post‐heating period when the temperature of the lesion boundary was less than a critical temperature. The final lesion areas estimated from multi‐slice (M/S) GRE, TSE, and histological slices were not statistically different. The model‐simulated tissue temperature distribution and lesion area closely corresponded to the GRE‐based MR measurements throughout the imaging experiment.

Conclusion

For normal tissue in vivo, the dynamics of tissue temperature distribution and lesion size during RF thermal ablation can be 1) monitored with GRE phase and magnitude images, and 2) simulated for prediction with a thermal model. J. Magn. Reson. Imaging 2007;26:123–132. © 2007 Wiley‐Liss, Inc.
Image metric‐based correction (autofocusing) of motion artifacts in high‐resolution trabecular bone imaging
Authors: Lin Wei , Ladinsky Glenn A. , Wehrli Felix W. , Song Hee Kwon
Published: July 2007

Purpose

To evaluate the performance of the autofocusing (AF) motion correction technique in high‐resolution trabecular bone imaging where image signal‐to noise ratio (SNR) is limited.

Materials and Methods

Raw data from 26 clinical three‐dimensional (3D) wrist exams were motion corrected using AF for both in‐plane rotation and translation. Changes in image metrics (a measurement of image sharpness) and structural parameters subsequently computed, were used to gauge the performance of the AF algorithm, and comparisons were made with translation‐only navigator‐corrected results.

Results

On average, AF generated images with higher image sharpness compared to the navigator echo technique. The average normalized gradient squared (NGS) metric improved by 0.40%, 0.73%, and 0.84%, respectively, following translation‐only navigator, translation‐only AF and combined rotation/translation AF. For all structural parameters, the rotation/translation AF resulted in an approximately two‐fold greater change compared to the navigator technique.

Conclusion

The data provide evidence that errors from subtle translational and rotational motion in the structural parameters in high‐resolution trabecular bone images are alleviated by AF and that the resulting improvements are superior to translation‐only 2D navigator correction. J. Magn. Reson. Imaging 2007;26:191–197. © 2007 Wiley‐Liss, Inc.
Noninvasive monitoring of chick development in ovo using a 7T MRI system from day 12 of incubation through to hatching
Authors: Bain Maureen M. , Fagan Andrew J. , Mullin James M. , McNaught Iain , McLean John , Condon Barrie
Published: July 2007

Purpose

To determine whether mild cooling of the egg reduces movement to the point where an ultra‐high‐field (7T) MRI system can be used to noninvasively monitor chick growth in ovo from 12 days incubation through to hatching.

Materials and Methods

Group A eggs were incubated at 37.5°C for 21 days. Group B eggs were removed from the incubator on days 12, 15, 17, 18, 19, and 20 of incubation, cooled for one hour, and then returned to the incubator. Group C eggs were cooled as for group B and then individually imaged for 25 minutes using a 7T MRI system before being returned to the incubator. The average size (volume) of the heart, liver, and brain at each stage of incubation was estimated from the T2‐weighted images and compared with existing values in the literature.

Results

The combination of cooling and MRI significantly reduced chick movement to allow excellent image acquisition at each stage of incubation. Repeated cooling and/or MRI did not significantly slow down or arrest the development of the chicks in either of the experimental groups.

Conclusion

MRI provides a powerful noninvasive tool to study chick development and the growth of individual organs, including the brain, liver, and heart, in ovo from 12 days' incubation. J. Magn. Reson. Imaging 2007;26:198–201. © 2007 Wiley‐Liss, Inc.
Partial replacement of Fe(o,o‐EDDHA) by humic substances for Fe nutrition and fruit quality of citrus
Authors: Cerdán Mar , Sánchez‐Sánchez Antonio , Juárez Margarita , Sánchez‐Andreu Juan J. , Jordá Juana D. , Bermúdez Dolores
Published: July 2007

The most widely used Iron (Fe) fertilizer in calcareous soils is the synthetic chelate Fe(o,o‐EDDHA). However, humic substances are occasionally combined with Fe chelates in drip irrigation systems in order to lower costs. We investigated the effect of various mixtures of Fe(o,o‐EDDHA) and a commercially available humic substance on Fe availability in a calcareous soil from Murcia, Spain (in vitro experiment) and on leaf Fe content and fruit‐quality attributes of Citrus macrophylla (field experiment). In the in vitro experiment, a calcareous soil was incubated for 15 d with solutions of sole Fe(o,o‐EDDHA) and humic substance and of a mixture of humic substance and Fe(o,o‐EDDHA) to determine the dynamics of available Fe. While the mixture did not significantly increase the available soil Fe, it did decrease the rate of Fe retention in the surface soil compared to sole Fe(o,o‐EDDHA). In the field experiment, the substitution in the application solution of 67% of Fe(o,o‐EDDHA) by commercial humic substance increased leaf P in lemon trees from 0.19% with sole Fe(o,o‐EDDHA) to 0.30% and leaf Fe from 94 mg kg–1 to 115 mg kg–1. Some quality parameters like vitamin C content and peel thickness were also improved with a partial substitution of Fe(o,o‐EDDHA) by humic substances. We conclude that a partial substitution of commercial Fe chelates by humic substance can improve crop Fe uptake and may thus be economically attractive. The underlying physiological mechanisms and ecological implications require further studies.
Modeling nitrate leaching and organic‐C build‐up under semi‐arid cropping conditions of N India
Authors: Mittal Shashi B. , Anlauf Rüdiger , Laik Ranjan , Gupta Atam P. , Kapoor Ashok K. , Dahiya Sunehara S.
Published: July 2007

Nitrate leaching, overall N balance, and organic‐C build‐up in a semi‐arid agro‐ecosystem in NW India was estimated from the results of a long‐term manurial trial with farmyard manure (FYM) and mineral‐N fertilizer in operation since 1967 at the Research Farm of CCS Haryana Agricultural University, Hisar, India. The model LEACHN was calibrated for the wheat‐growing period November 2000 to April 2001 and the leaching of nitrate during this period was predicted to 48 kg N ha–1without mineral‐N fertilization and 59 kg N ha–1with addition of 120 kg mineral‐N fertilizer, both with the addition of 15 t ha–1FYM. The N balance for the simulation period showed that the 120 kg N ha–1–mineral N fertilization compared to zero mineral N, both plus FYM, resulted in only slightly higher crop uptake, leaching losses, and NH3volatilization, and a negligible increase of N in organic matter. The largest amount remains as an additional build‐up of mineral N in the profile (84.3 kg N ha–1) which is prone to losses as ammonia or nitrate.

The model was used to simulate organic‐C build‐up with FYM and a decrease of organic C without FYM for a period of 33 y (1967–2000). The simulated C build‐up to about 0.1 g kg–1agreed very well with the measured values and showed that additional mineral‐N fertilization will not have any significant effect on organic‐C content. Simulations with the assumption of no FYM application showed a gradual decrease of organic C from its starting value of 0.046 g kg–1in 1967 down to almost half of this. This agreed well with the observed organic‐C values of 0.028 g kg–1as measured for unmanured plots.
Availability of organic nutrient sources and their effects on yield and nutrient recovery of tef [Eragrostis tef (Zucc.) Trotter] and on soil properties
Authors: Tulema Balesh , Aune Jens Bernt , Breland Tor Arvid
Published: July 2007

Inadequate nutrient and organic‐matter supply constitutes the principal cause for declining soil fertility and productivity in much of sub‐Saharan Africa (SSA). In a survey in Gare Arera, the central Ethiopian highland, farmyard manure (FYM) and compost enriched with ash were identified as underutilized organic nutrient sources. Mustard meal, a by‐product of mustard‐seed oil production, is also locally available. On‐farm experiments were carried out on two major soil types (Nitisol and Vertisol) to study effects of the organic fertilizers, synthetic fertilizer (urea + triple superphosphate) and an unfertilized control on the yield and yield components of tef [Eragrostis tef (Zucc) Trotter] and selected soil properties. Application of organic fertilizers at an N rate equivalent to that of urea produced grain yields of 82% and 99% of that produced with urea on Nitisol and Vertisol, respectively. The apparent N recovery from urea, mustard meal, FYM, and compost was, respectively, 31%, 25%, 16%, and 28% on Nitisol and 23%, 17%, 26%, and 21% on Vertisol. The mean agronomic efficiency for the organic and synthetic fertilizers on Nitisol was 20 and 24 kg grain (kg N)–1 applied, respectively, whereas on the Vertisol, it was 13 kg grain (kg N)–1 for both. On Vertisol, tef was most responsive to FYM and on Nitisol, it was most responsive to compost. Soil N and P contents increased due to organic‐fertilizer application. The results showed that compost enriched with ash is a good choice on Nitisol while FYM works well on Vertisol. Mustard meal can be applied on both soils.
Carbon sequestration under Miscanthus in sandy and loamy soils estimated by natural 13C abundance
Authors: Schneckenberger Katja , Kuzyakov Yakov
Published: July 2007

Most studies of soil organic‐carbon (SOC) dynamics using 13C natural abundance have been conducted with maize. Here, we present data about the sequestration of C derived from a perennial C4 plant, Miscanthus × giganteus (Greef et Deu.) grown on loamy and sandy soils for 9 and 12 y, respectively. We expected a higher contribution of Miscanthus‐derived C to SOC formation compared to maize because of (1) higher net biomass production by Miscanthus, (2) lower shoot‐to‐root ratio, (3) deeper roots, and (4) the absence of plowing. In both soils, there was a significant contribution of Miscanthus‐derived C down to 1 m soil depth. The maximal contents of 3.0 g C4‐C (kg soil)–1 and 2.4 g C4‐C (kg soil)–1 for loamy and sandy soil, respectively, were observed for the upper 0–10 cm layer. The decline in the amount of Miscanthus‐derived C with soil depth was significant for both soils, but without significant differences between the differently textured soils except the depth of 0–10 cm. The total SOC was similar under Miscanthus and under reference grassland in the sandy soil (both 6.4 kg C m–2 down to 1 m soil depth). Amounts of SOC were slightly higher under grassland at the loamy site (12.1 kg C m–2 compared with 11.2 kg C m–2). So, C accumulation under Miscanthus was similar to that under perennial grasses. After 9 and 12 y, respectively, the yearly incorporation of Miscanthus‐C in SOC of the upper 0–30 cm was 0.23 g C4‐C (kg soil)–1 y–1 in the loamy and 0.11 g C4‐C (kg soil)–1 y–1 in the sandy soil. This C4‐C incorporation in loamy soil under Miscanthus was 1.6–1.8 times higher than results reported for maize C4‐C incorporation in SOC grown under similar climatic conditions. In the sandy soil, the C4‐C incorporation under Miscanthus was nearly the same as under maize. The fraction of 22% of the Miscanthus residues remaining in SOC was similar to that one of maize residues in loamy soil. In sandy soil, only a small fraction of 9% of the Miscanthus residues was incorporated in SOC.
Drought pretreatment increases the salinity resistance of tomato plants
Authors: Cayuela Encarna , Muñoz‐Mayor Alicia , Vicente‐Agulló Francisco , Moyano Elena , Garcia‐Abellan Jose O. , Estañ Maria T. , Bolarín Maria C.
Published: July 2007

Agricultural productivity is worldwide subjected to increasing salinity problems. Various strategies are applied to overcome the deleterious effects of salinity on plants. This study was conducted in order to determine whether drought pretreatment of seedlings or seed pretreatment with NaCl increases the long‐term salinity resistance of tomato (Solanum lycopersicum L.) and whether the adaptive response to salinity is accompanied by physiological changes throughout the plant‐growth cycle. When plants were pretreated at the five‐leaf growth stage, the plant dry weight was significantly higher in drought‐pretreated than in non‐pretreated plants after 50 d of salt treatment. The positive effect of drought pretreatment applied at the five‐leaf stage was maintained throughout the entire growth cycle, as fruit yield of drought‐pretreated plants was 40% higher than that of non‐pretreated plants at the end of the harvest period (150 d of 70 mM NaCl treatment). Moreover, the most productive plants maintained lower Na+ and Cl– accumulation in their leaves until the end of the growth cycle, which shows that adaptation is a long‐term response during which the plants adjust their physiology to the environmental conditions. Salt resistance was also improved through seed pretreatment with NaCl. In conclusion, drought pretreatment applied at the five‐leaf stage or seed pretreatment with NaCl provide an alternative way to enhance salt resistance in tomato, and the increase in yield is associated with physiological changes throughout the plant‐growth cycle.
Multiphoton microscopy for monitoring intratissue femtosecond laser surgery effects
Authors: Wang Bao‐Gui , Riemann Iris , Schubert Harald , Schweitzer Dietrich , König Karsten , Halbhuber Karl‐Juergen
Published: July 2007

Background and Objective

Multiphoton microscopy/tomography has been used as a novel diagnostic method for corneal imaging with subcellular resolution. Here, we used this technique to monitor femtosecond laser intratissue surgery effects.

Materials and Methods

Multiphoton microscopy/tomography on rabbits based on intense 90 MHz femtosecond Ti: sapphire laser was realized at intensities of MW‐GW/cm2, whereas the surgical procedures were performed with the same system at a higher light intensity on the order of TW/cm2.

Results

Multiphoton microscopy/tomography proved capable of determining the target of interest, and of visualizing and optically evaluating the in vivo intrastromal laser surgical outcomes with high efficiency. More interesting, using this technique, activated intrastromal keratocytes (myofibroblasts) were detected in vivo 24 hours after intrastromal surgery.

Conclusion

Multiphoton microscopy/tomography is an efficient and convenient non‐invasive imaging method which can be used not only to assess intrastromal microsurgical performance but also to perform in vivo follow‐up observations on wound repair. Lasers Surg. Med. 39:527–533, 2007. © 2007 Wiley‐Liss, Inc.
Sialorrhea in Parkinson's disease: A review
Authors: Chou Kelvin L. , Evatt Marian , Hinson Vanessa , Kompoliti Katie
Published: July 2007

A significant number of patients with Parkinson's disease (PD) experience sialorrhea. This problem can cause social embarrassment, and because saliva pools in the mouth, may lead to aspiration pneumonia. Sialorrhea in PD is thought to be caused by impaired or infrequent swallowing, rather than hypersecretion. Oral medications, botulinum toxin injections, surgical interventions, radiotherapy, speech therapy, and trials of devices may be used to treat sialorrhea in PD, but few controlled trials have been published. This article reviews current knowledge regarding the frequency, etiology, assessment, and treatment of sialorrhea in PD. © 2007 Movement Disorder Society
Deep brain stimulation for the treatment of atypical parkinsonism
Authors: Shih Ludy C. , Tarsy Daniel
Published: July 2007

Deep brain stimulation (DBS) has gained widespread acceptance for improving motor function and disability in Parkinson's disease (PD). Patients with features suggestive of atypical parkinsonism (AP) usually have a poorer and less sustained response to levodopa and a poorer prognosis overall when compared with patients with PD. However, experience in the use of DBS with this group of patients is limited and evidence is lacking with regards to its efficacy and adverse effects. We review in detail the experience of DBS surgery in patients with several forms of AP including multiple system atrophy. On the basis of the limited available data reviewed here, DBS for patients with AP is not recommended. © 2007 Movement Disorder Society
Measurement of spin‐lattice relaxation times and chemical exchange rates in multiple‐site systems using progressive saturation
Authors: Galbán Craig J. , Spencer Richard G.
Published: July 2007

A new method for measuring spin‐lattice relaxation times and chemical exchange (CE) rate constants in multiple‐site exchanging systems is described. The method, chemical exchange and T1 measurement using progressive saturation (CUPS), was applied to determine T1s and analyze phosphorus exchange among phosphocreatine (PCr), ATP, and inorganic phosphate (Pi), mediated by creatine kinase (CK) and ATP synthase, using 31P‐MRS. Two‐site exchange was analyzed in vitro and in the rat leg, and three‐site exchange was analyzed in the rat heart. Data were fitted to a model of progressive saturation incorporating T1 relaxation and CE. For the in vitro system at 8.45T, we found T1(PCr) = 2.86 s and T1(γ‐ATP) = 1.72 s. For the rat gastrocnemius at 1.9T, we found T1(PCr) = 6.60 s and T1(γ‐ATP) = 2.06 s. For the rat heart at 9.4T, we found T1(PCr) = 3.35 s, T1(γ‐ATP) = 0.69 s, and T1(Pi) = 1.83 s. All of these values were within 20% of literature values. Similarly, the determined exchange rates were in the same range as published values. Using simulations, we compared CUPS with transient saturation transfer as a method for measuring T1s and rates. The two methods showed similar sensitivity to noise. We conclude that CUPS is a viable alternative for measuring T1s and CE rates in exchanging systems. Magn Reson Med 58:8–18, 2007. © 2007 Wiley‐Liss, Inc.
Accurate flip‐angle calibration for 13C MRI
Authors: Hancu Ileana , Watkins Ronald , Kohler Susan J. , Mallozzi Richard P.
Published: July 2007

13C imaging and spectroscopy in the presence of injected labeled compounds can vastly extend the capability of MRI to perform metabolic imaging. The details of imaging in the presence of injected compounds, however, pose new technological challenges. Pulse sequences, in general, rely on precise flip‐angle (FA) calibration to create high signal‐to‐noise ratio (SNR), artifact‐free images. Signal quantification also requires precise knowledge of the excitation FA. In MRI scans that rely on signal acquisitions from injected compounds, however, such FA calibration is challenged by low natural‐abundance 13C signal levels before injection, and by time‐varying signal following injection. A method to precisely set the FA at the 13C frequency based on FA calibration at the 23Na frequency is presented here. A practical implementation of a coil (a dual‐tuned, 23Na/13C low‐pass birdcage coil) suitable for this calibration in vivo is also documented. Accurate FA calibration is demonstrated at the 13C frequency for in vivo rat experiments using this approach. Magn Reson Med 58:128–133, 2007. © 2007 Wiley‐Liss, Inc.
Local planar gradients with order‐of‐magnitude strength and speed advantage
Authors: Aksel Bulent , Marinelli Luca , Collick Bruce D. , Von Morze Cornelius , Bottomley Paul A. , Hardy Christopher J.
Published: July 2007

A three‐axis uniplanar gradient coil was designed and built to provide order‐of‐magnitude increases in gradient strength of up to 500 mT/m on the x‐ and y‐axes, and 1000 mT/m for the z‐axis at 640 A input over a limited FOV (∼16 cm) for superficial regions, compared to conventional gradient coils, with significant gradient strengths extending deeper into the body. The gradient set is practically accommodated in the bore of a conventional whole‐body, cylindrical‐geometry MRI scanner, and operated using standard gradient supplies. The design was optimized for gradient linearity over a restricted volume while accounting for the practical problems of torque and heating. Tests at 320 A demonstrated up to 420‐mT/m gradients near the surface at efficiencies of up to 1.4 mT/m/A. A new true 2D gradient‐nonlinearity correction algorithm was developed to rectify gradient nonlinearities and considerably expand the imageable volumes. The gradient system and correction algorithm were implemented in a standard 1.5T scanner and demonstrated by high‐resolution imaging of phantoms and humans. Magn Reson Med 58:134–143, 2007. © 2007 Wiley‐Liss, Inc.
2D arbitrary shape‐selective excitation summed spectroscopy (ASSESS)
Authors: Qin Qin , Gore John C. , Does Mark D. , Avison Malcolm J. , de Graaf Robin A.
Published: July 2007

Conventional single‐voxel localization for MR spectroscopy (MRS) is restricted to selecting only rectangular‐shaped regions of interest (ROIs). The complexity of tissue shapes of interest and the desire to maximize the signal‐to‐noise ratio (SNR) while minimizing partial‐volume effects require more sophisticated localization techniques. A group of spatially selective RF pulses are proposed in this work for the measurement of spectra from regions of arbitrary shape based on using a radial trajectory in k‐space. Utilizing a single k‐line per excitation results in a broad spectroscopic bandwidth. However, spatial localization accuracy is compromised for nutation angles > 10° because of the small‐tip‐angle approximation of the Bloch equations. By interleaving multiple radial k‐lines per excitation with nonselective refocusing pulses, one can achieve accurate localization for nutation angles up to 90° while simultaneously maintaining the spectral bandwidth. The technique is described and compared with existing localization methods, and in vivo results are demonstrated. Magn Reson Med 58:19–26, 2007. © 2007 Wiley‐Liss, Inc.
A coupled damage–plasticity model for concrete based on thermodynamic principles: Part I: model formulation and parameter identification
Authors: Nguyen Giang D. , Houlsby Guy T.
Published: July 2007

The development of a coupled damage‐plasticity constitutive model for concrete is presented. Emphasis is put on thermodynamic admissibility, rigour and consistency both in the formulation of the model, and in the identification of model parameters based on experimental tests. The key feature of the thermodynamic framework used in this study is that all behaviour of the model can be derived from two specified energy potentials, following
procedures established beforehand. Based on this framework, a constitutive model featuring full coupling between damage and plasticity in both tension and compression is developed. Tensile and compressive responses of the material are captured using two separate damage criteria, and a yield criterion with a multiple hardening rule. A crucial part of this study is the identification of model parameters, with these all being shown to be identifiable and computable based on standard tests on concrete. Behaviour of the model is assessed against experimental data on concrete. Copyright © 2007 John Wiley & Sons, Ltd.
Aromatic VOC Removal by Formation of Microparticles in Pure Nitrogen Discharge Barrier Discharge
Authors: Ognier Stephanie , Cavadias Simeon , Amouroux Jacques
Published: July 2007

The treatment of an oxygen‐free gaseous effluent polluted by an aromatic VOC in a discharge barrier discharge (DBD) was investigated. The gaseous mixture was prepared by diluting toluene in N2. The efficiency was investigated in terms of pollutant conversion and by‐product formation. With regard to the pollutant conversion, the destruction efficiency was comparable to that obtained when air was used. However, an original polymerisation mechanism was evidenced by the use of N2 in the DBD reactor. SEM analysis showed that toluene reacts in the DBD to form micrometric particles that can easily be removed by filtration. The polymerisation pathways were determined using GC/MS and XPS analysis. The respective roles of the nitrogenated active species and the hydrodynamics of the discharge are shown.

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Developmental changes in rat surfactant lipidomics in the context of species variability
Authors: Bernhard Wolfgang , Schmiedl Andreas , Koster Grielof , Orgeig Sandra , Acevedo Christa , Poets Christian F. , Postle Anthony D.
Published: July 2007

Lung surfactant comprises mainly phosphatidylcholine (PC) species together with phosphatidylglycerols and surfactant proteins (SP) SP‐A to ‐D. Changes in the concentrations of its principal components dipalmitoyl‐PC, palmitoylmyristoyl‐PC, palmitoylpalmitoleoyl‐PC relative to developmental, structural and physiological differences are only partially understood. Particularly, their attribution to differences in air–liquid interface curvature, compared with dynamic parameters, such as respiratory rate, are controversial. We postulated that during alveolarization the changes in these principal PC components of surfactant differ from those in other phospholipid parameters, and that across endothermic vertebrates their concentrations are related to lung physiology rather than structure. We therefore investigated in rats from postnatal day (d)1 to d42 the pattern of surfactant phospholipids relative to alveolarization (d4–d14), and we discuss these changes in terms of molecular adaptation to pulmonary structure or physiology. Contrary to mammals with advanced alveolarization and increased respiratory rate (RR) at term, concentrations of dipalmitoyl‐PC (49–52%) and palmitoylmyristoyl‐PC (7–9%) in lung lavage fluid were identical at d1 and d42. At d7–d14, when in rats RR is increased, palmitoyl‐myristoyl‐PC transiently increased by 2.5‐ to 3.9‐fold at the expense of dipalmitoyl‐PC (−32% to 34%) and palmitoyl‐palmitoleoyl‐PC (−16%). Other lipidomic changes followed essentially different patterns of increase or decrease. Palmitoyl‐myristoyl‐PC was increased in large aggregates suggesting that it is an integral component of active surfactant. In the overall context of vertebrates, irrespective of age and lung structure, fractions of palmitoyl‐myristoyl‐PC, dipalmitoyl‐PC and palmitoyl‐palmitoleoyl‐PC correlate with differences in RR rather than alveolar curvature. In adult mammals, however, only concentrations of palmitoyl‐palmitoleoyl‐PC correlate with RR. Pediatr Pulmonol. 2007; 42:794–804. © 2007 Wiley‐Liss, Inc.
A sweat test centered protocol for the disclosure and diagnosis of cystic fibrosis in a newborn screening program
Authors: Doull I.J.M. , Hall S.J. , Bradley D.M.
Published: July 2007

We describe the development of a sweat test centered protocol for disclosure and diagnosis of Cystic Fibrosis. Our protocol aims to identify infants early, minimizes the time of uncertainly for the parents, and yet gives them time to begin to come to terms with the possibility of diagnosis. Over a 9‐year period 295,247 newborn infants were screened for CF in Wales, of whom 121 infants were diagnosed as having CF. During this period there were four false negatives (3.3%). Parental satisfaction with the process appears very high 6 months after disclosure. Pediatr Pulmonol. 2007; 42:773–778. © 2007 Wiley‐Liss, Inc.
New amphoteric surfactants containing a phosphoric acid group: II. Binary system of amphoteric/anionic surfactant of sodium 2‐(N‐2‐hydroxytetradecyl‐N‐methylamino)ethyl hydrogen phosphate
Authors: Tsubone Kazuyuki , Uchida Noriko , Mimura Kunio
Published: July 2007

We studied behaviors of the binary system of 2‐(N‐2‐hydroxytetradecyl‐N‐methylamino)ethyl hydrogen phosphate (C14‐HMP) and sodium dodecyl sulfate (SDS) in aqueous solution. We found that C14‐HMP reduced the ability of SDS to denature protein, to inhibit enzyme activity and to decrease transepidermal water loss. These phenomena were considered to be due to the interaction between the cationic group in the zwitterionic structure of C14‐HMP and the anionic group of sulfate in SDS molecule.

These behaviors suggest that C14‐HMP has a potential to reduce skin irritation when applied to personal care products such as cleaners and shampoos having anionic surfactants.
Thermal polymerization of methyl linolenate, alpha‐ and beta‐eleostearates
Authors: Paschke R. F. , Wheeler D. H.
Published: July 2007

The rates of polymerization of alpha and beta eleostearates agree with second order kinetics, as would be expected for a bimolecular Diels‐Alder addition. The all‐trans, beta isomer reacts faster than thecis, trans, trans alpha isomer, in agreement with knowncis, trans effects on diene activity.

The polymerization of normal linoleate follows an apparent first order reaction. It is suggested that conjugation is the slow rate determining monomolecular reaction, as has been proposed for the non‐conjugated linoleate isomers.
Drying oils from xylitol
Authors: Teeter H. M. , Bell E. W. , Cowan J. C.
Published: July 2007

Esters of xylitol with linseed and soybean fat acids were prepared. An average of four of the five hydroxyl groups in xylitol could be esterified, one group being lost by dehydration. These esters were evaluated in paints. Although thixotropy and crawling were objectionable in the soybean ester paints, the speed of drying and loss of residual tack were superior in comparison to the corresponding properties of paints containing only soybean oil as the vehicle.
Studies of the spectral characteristics of alkali‐isomerized autoxidized fatty acids
Authors: Privett Orville S. , Lundberg W. O.
Published: July 2007

The nature and extent of the interferences by autoxidized fatty acids in the application of spectrophotometric methods of fatty acid analysis are described.

A simplified countercurrent extraction procedure for the quantitative removal of the oxygenated fraction of autoxidized fatty acid esters was developed. By means of a preliminary interesterification process it was found possible to apply the extraction procedure in the analysis of autoxidized glyceridic fats.
Segregation of fatty acids by preferential neutralization
Authors: Nicholsen Richard , Formo Marvin W.
Published: July 2007

It has been shown that soybean fatty acids neutralized with a mixture of 40% of sodium hydroxide and 60% of barium hydroxide (on equivalent basis) form about 35% soluble soaps, which after separating from the insoluble soaps and splitting with sulfuric acid, form fatty acids of about 165 iodine number. From these acids a synthetic drying oil was prepared by esterification with glycerol which formed films almost as good as those of linseed oil.

It was also shown that the same process applied to fish oil fatty acids, but using in this case 60% of sodium hydroxide and 40% of barium hydroxide, resulted in a yield of about 50% of fatty acids of about 283 iodine number, which when esterified with glycerol gave a very fast drying synthetic drying oil forming tack‐free films.
The estimation of peroxides in fats and oils by the ferric thiocyanate method
Authors: Chapman R. A. , Mackay K.
Published: July 2007

Conclusions

All modifiactions of the ferric thiocyanate method investigated were affected by atmospheric oxygen. However, the interference in the Hills and Thiel (7) method and the Bolland (3) procedure was not as great as in the Lips, Chapman, and McFarlane (5) method. The results of Lea (8) were confirmed in respect to the lower values obtained when the atmosphere was rigorously excluded. Minimal results by the ferric thiocyanate procedure were possible only when carefully purified nitrogen was employed, and all possible precautions to prevent contact with air were observed. No other satisfactory method for offsetting this interference was found.

When the ferric thiocyanate procedures are conducted in the presence of air, the results, while high, are proportional to the iodimetric values. The former method, however, is much more sensitive than iodimetric procedures. Therefore under conditions where only comparative results are desired, such as in the assessment of the activity of antioxidants or in accelerated tests to predict the stability of a fat or oil, the ferric thiocyanate method should prove of considerable value. The Hills and Thiel (7) method was found to be the most satisfactory of those investigated since the use of benzene‐methanol as a solvent permits the use of larger samples and the reagents are considerably more stable than in other methods.
Nonedible seed oils as insect repellent
Authors: Khan M. W. Y. , Ahmad F. , Ahmad I. , Osman S. M.
Published: July 2007

Petroleum ether extracts of seeds at 10–1% concentration were tested for insecticidal activity against stored grain insects,Tribolium castaneum Herbst., in the laboratory. About 50 oils were tested, of which ten showed repellent, antifeedant property up to 1% concen‐tration.
Determination of trace metal content in corn oil by atomic absorption spectroscopy
Authors: Ooms B. , Van Pee W.
Published: July 2007

Atomic absorption spectrophotometry is used for the determination of Cu, Fe, K, Na, Ni and Zn in industrial refined corn oil. The results of five different analytical techniques are compared. Fair agreement is obtained between the char‐ashing method and the dilution procedure. Char ashing is a sensitive and useful technique, if handled correctly. Dilution, coupled to carbon‐rod atomization, is a reliable method. To eliminate errors, due to sample loss, a proper injection technique is required. Extraction methods suffer from incomplete recoveries, owing to deficient break up of the organometallic com‐pounds in oil
Chemical reactions involved in the deep‐ fat frying of foods: IX. Identification of the volatile decomposition products of triolein
Authors: May William A. , Peterson Robert J. , Chang Stephen S.
Published: July 2007

The acidic and nonacidic volatile decomposition products (VDP) pro‐duced by pure triolein maintained at 185 C with periodic injection of steam were collected, fractionated and identified. A total of 93 compounds were positively or tentatively identified. A number of the compounds found were identified for the first time in fats or oil VDP. Among these newly identified compounds are: unsaturated acids, keto‐substituted unsaturated acids, ω‐enals, unsaturated esters and an unsaturated γ‐lactone.
Detection of pig and buffalo body fat in cow and buffalo ghees by differential scanning calorimetry
Authors: Lambelet P. , Ganguli N. C.
Published: July 2007

Adding small amounts of pig or buffalo body fat to cow or buffalo ghee results in the appearance of an extra peak located at high temperature in the melting and crystallization curves as determined by the differential scanning calorimetry (DSC) technique. Ghee adulterations with these animal fats at levels down to 5% are clearly seen in the crystallization diagrams. Quantitative measurements can be obtained by this method in the case of adulterations with buffalo body fat. On the other hand, this method does not detect vegetable oils such as coconut oil, and gives similar results for cottonseed‐fed buffalo ghee and ghee adulterated with animal body fats.
Continuous acidulation of soapstock and recovery of acid oil
Authors: Mag T. K. , Green D. H. , Kwong A. T.
Published: July 2007

Requirements for water pollution abatement have created a need for much better recovery of fatty material from soapstock acidulation processes. The present methods of recovery lack reliability, or are relatively capital intensive, or both. A new, continuous system con‐sisting of equipment for acidulating the soapstock, decanting the bulk of acid oil from acid water, and treating the acid water in a coalescer for further separation of emulsified acid oil is described. The emphasis is on operating results from a pilot process using a variety of soapstocks. Fat concentrations below 150 ppm in acid water can be achieved reliably. The process is relatively compact, and simple to operate.
Crystallization characteristics of hydrogenated canola oil as affected by addition of palm oil
Authors: Yap Peck Hong , deMan J. M. , deMan L.
Published: July 2007

Addition of palm oil at levels of 5, 10 and 15% to selectively and nonselectively hydrogenated canola oil increased the time of isothermal crystallization at 20°C and delayed the appearance of the isothermal crystallization peak as determined by DSC. The degree of supercooling was also increased. Addition of palm oil to canola oil before selective or nonselective hydrogenation decreased the time of the appearance of the isothermal crystallization peak. Rates of crystallization were determined in selectively hydrogenated canola palm oil mixtures which followed first order kinetics.
Lipopeptidic surfactants: I. Neutral N‐lauroyl‐I‐arginine dipeptides from pure amino acids
Authors: Infante M. R. , Molinero J. , Bosch P. , Juláa M. R. , Erra P.
Published: July 2007

Neutral Nα‐lauroyl‐dipeptides such as Nα‐lauroyl arginylglycine and Nα‐lauroyl‐arginylphenylalanine as methyl ester (cationic surfactants) and free acid (amphoteric surfactants) derivatives have been prepared by synthetic methods. Fundamental surfactant properties and antimicrobial activity have been evaluated.

The properties of these compounds have been compared to the properties of the monomer derivatives Nα‐lauroyl‐arginine methyl ester (cationic) and Nα‐lauroyl‐arginine (amphoteric). These new molecules are very soluble in water, good surfactants, and exhibit a good antimicrobial activity, independently of their ionic character.
Phospholipids of palm oil (Elaeis guineensis)
Authors: Goh S. H. , Khor H. T. , Gee P. T.
Published: July 2007

Mesocarp oil ofElaeis guineensis provides 1000~2000 ppm of phospholipids. Thin layer chromatography revealed that the major components are phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylglycerol (PG). Minor components are phosphatidic acid (PA), diphosphatidylglycerol (DPG) and lysophosphatidylethanolamine (LPE), and traces of lysophosphatidylcholine (LPC) and phosphatidylserine (PS) are detectable. An artifact from enzymatic transphosphatidylation in methanolic solvents was isolated and characterized as phosphatidylmethanol (PM). Phospholipids are only present at low levels (20~80 ppm) in commercial crude palm oil and they usually account for a minor part of the total elemental phosphorus of the oil. It is desirable to have low levels of phospholipids in the oil to obtain better oxidative stability and bleaching properties.