bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal dietary habits and mycotoxin occurrence in human mature milk
Authors: Galvano Fabio , Pietri Amedeo , Bertuzzi Terenzio , Gagliardi Luigi , Ciotti Sabina , Luisi Stefano , Bognanno Matteo , La Fauci Luca , Iacopino Anna Maria , Nigro Francesco , Li Volti Giovanni , Vanella Luca , Giammanco Giuseppe , Tina Gabriella Lucia , Gazzolo Diego
Published: March 2008

During 2006, 82 samples of human mature milk were collected at Italian hospitals and checked for aflatoxin M1 (AFM1) and ochratoxin A (OTA) by immunoaffinity column extraction and HPLC. AFM1 was detected in four (5%) of milk samples (ranging from < 7 ng/L to 140 ng/L; mean level: 55.35 ng/L); OTA was detected in 61 (74%) of milk samples (ranging from < 5 ng/L to 405 ng/L; mean level: 30.43 ng/L. OTA levels were significantly higher (p ⪇ 0.05) in milk of habitual consumers of bread, bakery products and cured pork meat. No other statistically significant differences were observed although habitual consumers of pasta (p = 0.059), cookies (p = 0.061) and juices (p = 0.063) had mean contamination values of OTA higher than the moderate consumer. The very few AFB1 positive samples did not allow statistical comparisons. The present study confirms that the occurrence of OTA in human milk is related to maternal dietary habits. The findings support the possibility of dietary recommendations to woman, during pregnancy and lactation, aimed to tentatively reduce the OTA contamination of human milk.
Influence of substrate misorientation on properties of InGaN layers grown on freestanding GaN
Authors: Franssen G. , Suski T. , Kryśko M. , Łucznik B. , Grzegory I. , Krukowski S. , Khachapuridze A. , Czernecki R. , Grzanka S. , Mensz P. , Leszczyński M. , Porowski S. , Albrecht M.
Published: March 2008

The influence of GaN substrate misorientation on properties of Inx Ga1‐x N epilayers (0.05 < x < 0.1) has been examined. X‐ray Bragg reflection, photoluminescence (PL) peak energy and full width at half maximum were analyzed. Higher misorientation angles with respect to the c‐plane (up to 2.30°) give lower average In incorporation in InGaN layers, causing a blue shift of the PL peak energy. In contrast with expectations, higher misorientation (i.e., lower In content) leads to higher alloy disorder. This is reflected in the spectral width of PL lines and in a well‐pronounced S‐shape of PL vs. temperature for more misoriented samples. The obtained results clearly show that the misorientation of the substrate can be used as a parameter for the growth of InGaN layers, enabling the control of crucial light emitting device parameters such as emission energy and In fluctuation effects. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Provably secure RSA‐type signature based on conic curve
Authors: Dong Xiaolei , Qian Haifeng , Cao Zhenfu
Published: March 2008

In electronic communication and wireless communication, message authentication should be necessary. However, traditional method message authentication code (MAC) employs a symmetric cryptographical technique and it needs to keep a shared private key between two parties. For convenience, people now begins to use public key techniques to provide message authentication. In wireless communication, we shall save more space for message itself because of the limited resources. Therefore, we believe that our proposed digital signature scheme will be more fitful for this kind of communication due to the following merits: (1) in addition to inheriting the merits of RSA signature such as high verification efficiency, the proposed scheme also shows its advantage over RSA by resisting low public key exponent attack; (2) comparing with 1024 bits RSA, our digital signature scheme can sign 2048‐bit long message once, and generate a signature with 1025 bits length which doubles the capacity of the 1024‐bit RSA signature; (3) the scheme is provably secure and its security is tightly related to the hardness of conic‐based (CB)‐RSA assumption. Copyright © 2008 John Wiley & Sons, Ltd.
DCR‐MAC: distributed cognitive radio MAC protocol for wirelessad hocnetworks
Authors: Yoo Sang‐Jo , Nan Hao , Hyon Tae‐In
Published: March 2008

The MAC protocol for a cognitive radio network should allow access to unused spectrum holes without (or with minimal) interference to incumbent system devices. To achieve this main goal, in this paper a distributed cognitive radio MAC (DCR‐MAC) protocol is proposed for wirelessad hocnetworks that provides for the detection and protection of incumbent systems around the communication pair. DCR‐MAC operates over a separate common control channel and multiple data channels; hence, it is able to deal with dynamics of resource availability effectively in cognitive networks. A new type of hidden node problem is introduced that focuses on possible signal collisions between incumbent devices and cognitive radioad hocdevices. To this end, a simple and efficient sensing information exchange mechanism between neighbor nodes with little overhead is proposed. In DCR‐MAC, eachad hocnode maintains a channel status table with explicit and implicit channel sensing methods. Before a data transmission, to select an optimal data channel, a reactive neighbor information exchange is carried out. Simulation results show that the proposed distributed cognitive radio MAC protocol can greatly reduce interference to the neighbor incumbent devices. A higher number of neighbor nodes leads to better protection of incumbent devices. Copyright © 2008 John Wiley & Sons, Ltd.
Serum chemistry concentrations of captive woolly monkeys (Lagothrix lagotricha)
Authors: Ange‐van Heugten Kimberly , Verstegen Martin , Ferket Peter R. , Stoskopf Michael , van Heugten Eric
Published: March 2008

Woolly monkeys (Lagothrix sp.) are threatened species and numerous zoos have failed to sustain successful populations. The most common causes of death in captive woolly monkeys are related to pregnancy and hypertension. The objective of this retrospective study was to evaluate serum concentrations of a large number of captive woolly monkeys to establish baseline means and compare these concentrations with their closest related species to determine potential abnormalities. Serum analyses from 30 woolly monkeys housed at two institutions (Apenheul, The Netherlands and The Louisville Zoo, KY, USA) over 12 yr were collected. The statistical model included gender, age group (young, 0–4 yr of age; middle, 5–9 yr; and old, 10+ yr), and zoological institution. All panel result means were similar to previously reported concentrations for howler (Alouatta sp.) and spider monkeys (Ateles sp.) with the possible exception of alanine aminotransferase and γ‐glutamyl‐transferase being higher, whereas creatinine and phosphorus were lower. The serum glucose mean of 6.7 mmol/L is above the baseline range for humans and spider monkeys. Alkaline phosphatase (ALP), alanine aminotransferase, and sodium (Na) were higher in females and magnesium (Mg) was higher in males (P<0.05). ALP, Mg, and phosphorus were highest (P<0.05) and calcium and sodium tended to be highest (P<0.10) in the oldest animals. Ferritin tended to be highest (P<0.10) in the oldest animals. Albumin, ALP, chloride, Na, and total bilirubin were higher for Zoo A, whereas γ‐glutamyl‐transferase, glucose, and lactate dehydrogenase were lower for Zoo A (P<0.05). Areas of potential woolly monkey health risk were noted and discussed. Future studies are needed to determine free‐ranging serum concentrations to elucidate parameters that contain aberrant concentrations and decrease health status. Zoo Biol 27:188–199, 2008. © 2008 Wiley‐Liss, Inc.
Separation of the methyl esters of oleic, linoleic, and linolenic acids by column chromatography using cation exchange resin containing silver ion
Authors: Wurster C. F. , Copenhaver J. H. , Shafer P. R.
Published: March 2008

By taking advantage of the tendency of silver ion to form complexes with unsaturated compounds, the methyl esters of oleic, linoleic, and linolenic acids have been cleanly separated in good yield by column chromatography. The silver ion was supported by means of a cation exchange resin; no silver was ever eluted from the column. Aqueous methanol, pure methanol, and ethanol saturated with butene‐1 were employed as solvents.
The determination of sodium, potassium and magnesium in surfactants by flame spectrophotometry
Authors: Beck E. C. , Wilson K. J. , Jungermann Eric
Published: March 2008

A method for determining sodium, potassium, and magnesium in soaps and detergents by means of flame spectrophotometry is described in detail. Sodium and/or potassium are normally present in high percentages; magnesium is usually found in relatively low concentrations as part of the antioxidant system of bar soaps. The spectrophotometric procedure has the following advantages over commonly used wet methods: 1) rapidity, 2) simplicity, and 3) the cations are determined directly and independently of each other. Soap additives, such as perfumes, colors, super‐fatting agents or germicides do not interfere with this method. Possible interferences between sodium, potassium, and magnesium cations were evaluated and eliminated. Typical examples, including toilet soaps, combination soap‐detergent bars, and sprayed detergents are described.
Kinetic studies of detergency. I. Analysis of cleaning curves
Authors: Bourne M. C. , Jennings W. G.
Published: March 2008

The kinetics of removal of thin films of pure radioactive tristearin from a stainless‐steel surface by .03M NaOH was studied in a circulation system. The data obtained are consistent with the presence of two species of tristearin, each species being removed simultaneously by a first‐order process and behaving independently of the other. The principal evidence for the existence of the two species is the excellent agreement of the experimental data with the mathematical techniques of kinetics over a wide range of experimental conditions. Rate constants for the removal of each species and the relative proportions of the two species are given for different experimental conditions. It is shown that the difference between the two species must be based on some physical factor, and possible explanations are discussed. The presence of two species gives a satisfactory explanation for hitherto unexplained results of other workers.
Kinetic studies of detergency. II. Effect of age, temperature, and cleaning time on rates of soil removal
Authors: Bourne M. C. , Jennings W. G.
Published: March 2008

The effects of variation in temperature, flow rate, cleaning time, and age were studied in a model circulation system. The results are recorded as changes in the rate constants k1 and k2 and changes in the relative proportions of the two soil species. The removal of tristearin in this simple system was found to proceed by two independent mechanisms, acting simultaneously. The first, named the 舠flow mechanism,舡 is dependent on time, and its rate increases with flow rate. The second, which the authors term the 舠Duprȳ mechanism,舡 is not dependent upon time and arises from the air‐detergent interface that moves over the surface. The Duprȳ effect is independent of flow rate at all rates of flow. In most of the experiments the DuprȲ mechanism accounted for about 90% of the removal of tristearin. A comparison is made between the removal of monomolecular films and thin polymolecular films. It is shown that the empirical finding of apparently simple first‐order kinetics is not inconsistent with the complex processes that remove tristearin from the surface.
Quantitative gas liquid chromatographic analysis of butterfat triglycerides
Authors: Kuksis A. , McCarthy M. J. , Beveridge J. M. R.
Published: March 2008

Gas liquid chromatographic triglyceride separation by carbon number, and integration of the area response obtained in the hydrogen flame ionization detector, has permitted the calculation of the following molar proportions for the various triglyceride types in a blended butterfat sample: C24 0.5, C25 0.08, C26 0.57, C27 0.18, C28 0.81, C29 0.17, C30 1.15, C31 0.2, C32 3.1, C33 0.34, C34 5.41, C35 1.0, C36 10.6, C37 1.2, C38 12.8, C39 1.15, C40 10.7, C41 1.0, C42 6.1, C43 0.58, C44 5.15, C45 0.6, C46 5.8, C47 1.0, C48 6.45, C49 1.47, C50 8.5, C51 1.43, C52 6.95, C53 1.05, C54 4.0. The validity of these estimates was verified by similar determinations performed on molecular distillates of butterfat and on butterfats with known amounts of added saturated and unsaturated long chain triglycerides. The fatty acid carbon recoveries estimated on the basis of the observed triglyceride peak proportions were of the order of 95% or better.

A comparison of the experimentally determined triglyceride type distributions with those calculated on the basis of a completely random fatty acid arrangement for the blended and the molecularly distilled samples showed considerable differences, the most apparent of which was the greater proportion of both short and long chain triglycerides consistently predicted for the random population. On the basis of these studies, it is suggested that butterfat possesses a non‐random fatty acid distribution which is reflected in its triglyceride type distribution.
A comparison of the cup refining loss and neutral oil determinations for evaluating crude soybean oil
Authors: Potts T. J.
Published: March 2008

Data from 833 non‐degummed and degummed soybean oil samples, which were analyzed by both the neutral oil loss and cup loss methods, were examined, and it was found that the total premiums paid under the cup loss method and the proposed National Soybean Processors Association Technical Committee舗s neutral oil analysis were the same. However, better quality oils would have received a higher premium, while poorer oils would have been penalized more heavily under the new procedure.
Long chain alkanesulfonates and 1‐hydroxy‐2‐alkanesulfonates: Structure and property relations
Authors: Weil J. K. , Smith F. D. , Stirton A. J. , Bistline R. G.
Published: March 2008

Even chain sodium alkanesulfonates from the Strecker reaction, odd chain sodium alkanesulfonates from the alkaline decarboxylation of ॅ‐sulfo acids, and sodium 1‐hydroxy‐2‐alkanesulfonates from the reduction of esters of ॅ‐sulfo acids were compared with respect to Krafft point, critical micelle concentration, detergency and foam height. Sodium alkanesulfonates and crude fusion products from the ॅ‐sulfo acids (mixtures of alkanesulfonates of one less carbon atom with a lesser amount of a soap of two less carbon atoms) are more soluble and have better detergent and foaming properties. Sodium 1‐hydroxy‐2‐alkanesulfonates resemble monosodium salts of ॅ‐sulfo acids.

Alkanesulfonic acids and 1‐hydroxy‐2‐alkane‐sulfonic acids obtained from the sodium salts by ion exchange have lower Krafft points and are more readily soluble. The critical micelle concentrations of 1‐hydroxy‐2‐alkanesulfonic acids and ॅ‐sulfo acids are nearly the same and about equal to those of alkanesulfonic acids of one less carbon atom.
N,N‐Bis(2‐Acyloxyethyl) amides of long chain fatty acids as plasticizers
Authors: Magne F. C. , Mod R. R. , Skau E. L.
Published: March 2008

A series of N,N‐bis‐(2‐acyloxyethyl) amides and a few related derivatives have been prepared wherein a long chain fatty acid or fatty acid mixture comprises 33 mole percent of the total acyl groups present: the other 66 mole percent being either a short chain aliphatic or aromatic acyl group. Both ordered and random diesteramides have been prepared. All have been tested as plasticizers for vinyl chloride copolymers. Some are acceptable as nitrile rubber softeners and cellulose acetate plasticizers. The ordered diesteramides give the best overall performance as plasticizers, but it is possible to achieve acceptable performance levels in semi‐ordered diesteramides.
Suitability of lipid extraction procedures for gas‐liquid chromatography
Authors: Sheppard A. J.
Published: March 2008

A comparison of two methods of extracting liver tissue lipids has been made using a limited amount of experimental material. The extracts prepared by a procedure using Bloor舗s reagent were more stable in storage, contained nearly 100% more total lipids and phospholipids, and produced more uniform and reproducible patterns on gas chromatographic analysis, than extracts of the same liver prepared by a diethyl ether Soxhlet extraction.
The estimation of lactic acid in lactylated monoglycerides and shortenings containing lactylated monoglycerides
Authors: Pohle W. D. , Gregory R. L. , van Giessen B.
Published: March 2008

A titrimetric method has been presented for the determination of lactic acid in lactylated monoglycerides and shortenings containing these products, when the only water soluble acid present is lactic acid. Analyses by this method: of knowns, samples from a material balance test, and commercial products, indicate that it is applicable to these types of product. Comparison of analyses of the material balance samples and commercial products by the titrimetric method and the colorimetric p‐phenylphenol method indicated that the latter gave lower and more variable results.
Caloric availability and digestibility of new‐type fats
Authors: Booth A. N. , Gros A. T.
Published: March 2008

Digestibility and caloric availability of new‐type fats were determined by feeding these products to young rats while on a restricted caloric intake. Amylose stearate, amylose palmitate, amylose oleate, distearin adipate, and glycerol adipate were low in both categories. Diolein fumarate was completely digested but poorly utilized. These materials were compared with common oils and fatty acids. These new‐type fats have potential use as pan greases and surface coatings for foods.
Cis‐trans isomerization of oleic, linoleic and linolenic acids
Authors: Litchfield Carter , Lord J. E. , Isbell A. F. , Reiser Raymond
Published: March 2008

The equilibrium composition ofcis andtrans isomers obtained by isomerizing oleic, linoleic, and linolenic acids with selenium or nitrous acid has been studied using gas chromatography and infrared spectroscopy. The oleic/elaidic equilibrium mixture was found to contain 75舑80% elaidic acid instead of the generally accepted 66% value. It is felt that the greater accuracy of gas chromatography and infrared analyses over older methods allows this equilibrium to be defined with greater precision.

Similar studies on thecis‐trans isomerization of linoleic and linolenic acids indicated that their equilibrium mixtures also contained 75舑80%trans double bonds. With linoleic acid, thesetrans bonds were shown to be randomly distributed among the double bonds present.

Cis‐trans isomerization of linoleic or linolenic acids with selenium produced by‐products having elution times equivalent to 18蝘2, 18蝘1, and 18蝘0 on a gas chromatograph. No such by‐products were observed when oleic acid was isomerized. Apparently some type of hydrogen‐transfer reaction accompanies thecis‐trans isomerization of polyunsaturated acids with selenium.
Structural correlation of unsaturated fatty acid esters through graphical comparison of gas‐liquid chromatographic retention times on a polyester substrate
Authors: Ackman R. G.
Published: March 2008

The correlation of structures of esters of certain unsaturated fatty acids is possible through a linear relation when logarithms of retention time on polyester substrates are plotted against the number of carbon atoms in the fatty acid chain.

This correlation is independent of any relation to the retention times of the esters of the saturated fatty acids, and depends solely on the fatty acid chain length, the number of double bonds, and the length of the end carbon chain. It appears to depend on the influence of the latter on vapor pressure.

A sound basis is thus provided for advocating a modified equivalent chain length system, virtually independent of temperature effects, and based on certain commonly occurring monounsaturated acids rather than on the saturated acids.
An analysis of separation factors applicable in the gas‐liquid chromatography of unsaturated fatty acid methyl esters on a polyester substrate
Authors: Ackman R. G.
Published: March 2008

The employment of gas‐liquid chromatography (GLC) separation factors between methyl esters of unsaturated fatty acids is feasible as a means of tentative identification, either between acids of one chain length and differing numbers of double bonds, or between acids of one chain length and the same number of double bonds in differing positions, provided the acid structures are appropriately grouped by end carbon chain. The modification of separation factors by temperature, chain length, number of double bonds, or position of double bonds is apparent from examination of a larger number of examples than was hitherto available. Examples of the usefulness of separation factors in identifying unknowns or predicting retention times are given.
The pancreatic hydrolysis of natural fats. III. The influence of the extent of hydrolysis on monoglyceride composition
Authors: Coleman M. H.
Published: March 2008

Samples of lard and illipȳ butter have been hydrolyzed with pancreatic lipase for varying lengths of time, and the products estimated and analyzed. The composition of the monoglycerides from both fats, and of the tri‐ and diglycerides of illipȳ butter, were independent of the degree of hydrolysis; but the tri‐ and diglyceride fractions of lard became progressively more saturated with increasing hydrolysis. These results provide evidence for the sort of fatty acid distribution in fats envisaged by VanderWal. Representation of the results by a theoretical expression suggests that the rates of hydrolysis of the tri‐ and diglycerides are similar. It is concluded that analysis of the monoglycerides provides a better estimate of the distribution of fatty acids in natural fats than the analysis of the free fatty acids.
Gossyverdurin: A newly isolated pigment from cottonseed pigment glands
Authors: Lyman C. M. , El‐Nockrashy A. S. , Dollahite J. W.
Published: March 2008

The constituents of cottonseed pigment glands were fractionated by the use of column chromatography with DEAE cellulose ion exchanger and silicic acid, and a new green pigment was isolated. The acute oral toxicity of the new pigment was determined using rats as experimental animals. The LD‐50 value obtained was 0.66 g/kg of body weight indicating that the new pigment which was named gossyverdurin is the most toxic of any cottonseed pigment so far reported. Gossyverdurin showed absorption maxima at 250, 370, and 560 mॖ. Reaction with para‐anisidine under the conditions used for the determination of gossypol gave an absorption peak similar to that obtained with gossypol indicating that the new compound is structurally related to gossypol. In addition a second peak at 342 mॖ appears on reaction with para‐anisidine indicating important structural differences between gossypol and gossyverdurin.
The separation of glycerides by liquid‐liquid column partition chromatography
Authors: Black B. C. , Hammond E. G.
Published: March 2008

A liquid‐liquid partition chromatography method was developed to separate triglycerides. The solvent was a two phase mixture of acetone, heptane, and water supported on silane treated celite. A study was made of the best means for equilibrating the solvents and support, packing the column, and introducing the sample. The effect of various operating variables such as flow rate, sample size, column length, and solvent compositions was studied using trilaurin and trimyristin as model glycerides. Under the best conditions achieved, it was calculated that glycerides differing by two carbon atoms or one double bond would not separate completely, but glycerides differing by two double bonds or four carbon atoms would be separated. Cocoa butter, a relatively simple triglyceride, was fractionated, and the fatty acid composition of each fraction was determined by gas chromatography. The glyceride composition was calculated and compared with theoretical compositions. The results indicate that useful glyceride separation can be obtained with this system. Probably even more useful separations could be obtained if a more sensitive device were used to detect the triglycerides in the effluent. This would allow the use of solvent compositions which give larger retention volumes and more plate efficiency.
Methods for improving yields of cyclic acid from linseed oil
Authors: Friedrich J. P. , Palmer J. C. , Bell E. W. , Cowan J. C.
Published: March 2008

Liquid C‐18 saturated monocarboxylic acids, which are termed 舠cylic acids舡 because they contain a ring structure, have been prepared by the action of excess sodium hydroxide on linseed oil in ethylene glycol at elevated temperatures, followed by distillation and hydrogenation of the resulting free fatty acid monomers and by separation of the straight‐chain components by low‐temperature crystallization from acetone. In a survey of other possible catalysts and reaction conditions, cyclic acid yields were improved from the previously reported 32.4 g to 43.5 g of cyclic acid per 100 g of linseed fatty acids by removing water from the starting materials and using the monosodium derivative of ethylene glycol as catalyst. The corresponding amount of polymer formed decreased because of a decrease in hydroxylation and subsequent polyester formation.
Vernonia anthelmintica (L.) Willd. enzyme studies conversion of epoxyoleic acid to (+)‐threo‐12,13‐dihydroxyoleic acid
Authors: Scott W. E. , Krewson C. F. , Luddy F. E. , Riemenschneider R. W.
Published: March 2008

Vernonia anthelmintica (L.) Willd. seed was found to contain enzymes that were active only after the seed was ground. By deactivation of the enzymes, an oil rich in trivernolin (the triglyceride of epoxyoleic acid) was produced, and pure trivernolin was isolated. Acceleration of the enzyme activity altered the composition of the oil as evidenced by changes in free fatty acid content, iodine values, and oxirane oxygen (epoxy) content. Investigation showed that these changes were due, at least partially, to the conversion of epoxyoleic acid to (+)‐threo‐12,13‐dihydroxyoleic acid, which was isolated in pure form. Pure (蜢)‐threo‐12,13‐dihydroxyoleic acid was prepared by acetolysis ofV. anthelmintica seed oil. Neither of these isomers had been obtained previously from mature,V. anthelmintica seed.
The reactions of alkylene oxides with various butyl and other alcohols
Authors: Stockburger G. J. , Brandner J. D.
Published: March 2008

Acid‐catalyzed additions of ethylene oxide to various isomeric butyl alcohols were observed to agree with the Poisson equation and the products were relatively unaffected in composition by changes in the reactants or reaction conditions. Base‐catalyzed reactions yielded products whose composition could be more closely approximated by Weibull and Nycander舗s equations. The product composition, although largely independent of reaction conditions, varied with the structure of the starting alcohol. Good correlation was found between the relative acidities of the starting alcohols and their reaction products and Weibull‐Nycander distribution constants for base‐catalyzed reactions of ethylene oxide and propylene oxide. It is believed that the relative acidities of the alcohol and its epoxide adduct influence the product composition through the equilibrium reaction:

ROH+RO (CH2CH2O)=X薔RO蜢+RO(CH2CH2O)xH
Methanesulfonic acid catalyzed additions to oleic acid and cyclohexene. III. Addition of acids and substituted phenols
Authors: Eisner Abner , Perlstein Theodore , Ault W. C.
Published: March 2008

Benzoic acid adds to oleic acid in methanesulfonic acid as catalyst‐solvent to form an addition product in 30% yield. Saponification studies on the product reveal that the addition is made via the carboxyl group and no rearrangement of the initial product takes place. A number of substituted benzoic acids were also tried but the yield of addition product was nil. Data are included for the experiments with a number of phenols not previously reported. These include: o‐chlorophenol,2,6‐di‐tert.‐butylphenol, 2,4,6‐trichlorophenol, resorcinol, 5‐n‐pentadecylresorcinol, hydroquinone, methyl salicylate, and 3‐n‐pentadecylphenol. Good yields of addition products of cyclohexene are obtained using methanesulfonic acid as catalyst‐solvent and the same nucleophiles employed previously.
The psoas muscle as cause of low back pain in infantile cerebral palsy
Authors: Marrè-Brunenghi G. , Camoriano R. , Valle M. , Boero S.
Published: March 2008

Psoas muscle spasticity is hypothesised as a rare cause of low back pain in patients with infantile cerebral palsy. The authors describe a new manoeuvre for the study of psoas tenderness and ultrasound (US)-guided transabdominal botulinum toxin injection technique. A possible causal relationship between psoas tension and low back pain was found incidentally in two examined cases. In subsequent patients, botulinum toxin was injected and, in cases of disappearance of symptoms, the psoas tendon was sectioned at the pelvic brim with definitive disappearance of pain. The relationship between psoas tension and low back pain in patients with infantile cerebral palsy seems likely, given the result in the four patients.
Magnetic and atomic structure parameters of Sc-doped barium hexagonal ferrites
Authors: Yang Aria , Chen Yajie , Chen Zhaohui , Vittoria Carmine , Harris V. G.
Published: March 2008

Scandium-doped M-type barium hexagonal ferrites of the composition BaFe12−xScxO19 are well suited for low frequency microwave device applications such as isolators and circulators. A series of Sc-doped M-type barium hexagonal ferrite powders (x=0–1.2) were prepared by conventional ceramic processing techniques. The resulting powders were verified to be pure phase and maintain the nominal chemical stoichiometry by x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Static magnetic measurements indicated that both saturation magnetization and uniaxial magnetocrystalline anisotropy field decreased with increasing concentration of scandium. Extended x-ray absorption fine structure measurements were carried out to clarify the correlation between the magnetic and atomic structure properties. It is found that the substituted Sc has a strong preference for the bipyramidal site. Nevertheless, the substitution did not introduce additional atomic structural disorder into the barium hexagonal structure. The structural study provided important evidence to quantitatively explain the change in dc and microwave magnetic properties due to Sc ion doping.
Structures and relative stability of medium- and large-sized silicon clusters. VI. Fullerene cage motifs for low-lying clusters Si39, Si40, Si50, Si60, Si70, and Si80
Authors: Yoo Soohaeng , Shao N. , Zeng X. C.
Published: March 2008

We performed a constrained search, combined with density-functional theory optimization, of low-energy geometric structures of silicon clusters Si39, Si40, Si50, Si60, Si70, and Si80. We used fullerene cages as structural motifs to construct initial configurations of endohedral fullerene structures. For Si39, we examined six endohedral fullerene structures using all six homolog C34 fullerene isomers as cage motifs. We found that the Si39 constructed based on the C34(Cs:2) cage motif results in a new leading candidate for the lowest-energy structure whose energy is appreciably lower than that of the previously reported leading candidate obtained based on unbiased searches (combined with tight-binding optimization). The C34(Cs:2) cage motif also leads to a new candidate for the lowest-energy structure of Si40 whose energy is notably lower than that of the previously reported leading candidate with outer cage homolog to the C34(C1:1). Low-lying structures of larger silicon clusters Si50 and Si60 are also obtained on the basis of preconstructed endohedral fullerene structures. For Si50, Si60, and Si80, the obtained low-energy structures are all notably lower in energy than the lowest-energy silicon structures obtained based on an unbiased search with the empirical Stillinger–Weber potential of silicon. Additionally, we found that the binding energy per atom (or cohesive energy) increases typically >10meV with addition of every ten Si atoms. This result may be used as an empirical criterion (or the minimal requirement) to identify low-lying silicon clusters with size larger than Si50.
Effect of electron distribution in InN films on infrared reflectance spectrum of longitudinal optical phonon-plasmon interaction region
Authors: Ishitani Yoshihiro , Wang Xinqiang , Che Song-Bek , Yoshikawa Akihiko
Published: March 2008

The infrared reflectance spectra of InN∕GaN structures are analyzed in two energy regions for higher and lower energy branches of the longitudinal optical phonon-plasmon coupled modes. For samples with smaller residual electron density than 5×1017cm−3 and the film thickness of 0.7–4μm, the spectra down to 200 or 250cm−1 shows the existence of the electron accumulation with sheet electron density of 1013cm−2 in the vicinity of the InN∕GaN-interface. The effect of the surface electron accumulation on the spectra is not identified, which is possibly caused by the small mobility of the order of 10cm2∕Vs or less for the surface electrons. The electron density of the inside bulk region is obtained with account of this interface accumulation. However, for samples with higher electron density and thickness of several micrometers a model with uniform electron density well reproduce the experimental spectra. With this spectrum fitting we extract the electron properties inside the bulk region for samples with the thickness of about 700nm or larger.
Infrared-to-green and blue upconversion in Tm3+-doped TeO2–PbO glass
Authors: Rai Vineet Kumar , de S. Menezes Leonardo , de Araújo Cid B.
Published: March 2008

The infrared-to-visible upconversion (UC) in Tm3+-doped TeO2–PbO glass was investigated by exciting the samples with a Q-switched neodymium doped yttrium aluminum garnet laser operating at 1064nm. UC emission bands at ∼454, ∼482, and ∼518nm corresponding, respectively, to the transitions D21→F43, G41→H63, and D21→H53 were observed. Based on the dependence of the UC signals as a function of the Tm3+ concentration and excitation intensity, we concluded that the generation of the UC emissions involves excited state absorption and cross relaxation among Tm3+ ions.
Electrokinetic separation of co-solutes into bimodal fibers by electrospinning
Authors: Wu Chunya , Nagata Shinobu , Tepper Gary C. , McLeskey James T.
Published: March 2008

Composite and chemically/physically distinct fibers of sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate] (PTEBS) and polyethylene oxide (PEO) were formed by electrospinning from a homogeneous aqueous solution containing PTEBS and PEO co-solutes. Composite nanofibers of diameter of ∼60nm were electrospun from an aqueous solution. The addition of ammonium hydroxide (NH4OH) to the water solution resulted in “bimodal” electrospun fibers consisting of distinct large diameter white PEO fiber segments and small diameter black PTEBS fiber segments. The optical absorption spectrum of the composite PTEBS/PEO nanofibers did not exhibit the characteristic peak around 460nm, which is present in the bulk spectrum.
Time-resolved measurement of the local lattice temperature in terahertz quantum cascade lasers
Authors: Vitiello Miriam S. , Scamarcio Gaetano , Spagnolo Vincenzo
Published: March 2008

We measured the time dependence of the local lattice temperature in terahertz quantum cascade lasers with surface plasmon waveguides. The time constants for heat extraction from the active region (0.15–0.29μs) are approximately ten times shorter than those associated with heat extraction from the substrate, thereby showing the dominant role of the substrate-heat sink coupling. Thermal diffusivities D=0.052cm2∕s (Ds=3.9cm2∕s) and thermal diffusion lengths μ=1.2μm (μs=31μm) in the active region (substrate) have been extracted by fitting the solution of the heat transport equation to the experimental data.
Electrical properties of Be-implanted polycrystalline cubic boron nitride films
Authors: He B. , Zhang W. J. , Zou Y. S. , Chong Y. M. , Ye Q. , Ji A. L. , Yang Y. , Bello I. , Lee S. T. , Chen G. H.
Published: March 2008

P -type conductivity of polycrystalline cubic boron nitride (cBN) films was achieved by implantation of beryllium ions. The effects of implantation doses and annealing on the phase composition and electrical properties of cBN films were studied. A reduction in resistivity by seven orders of magnitude was observed. Hall measurement revealed a corresponding hole concentration of 6.1×1018cm−3 and mobility of 3cm2∕Vs. The activation energy was estimated to be 0.20±0.02eV from the temperature dependence of resistance. The electrical properties of Be-implanted films are comparable to that of Be-doped cBN single crystals synthesized by high-pressure and high-temperature method.
Network properties of genes harboring inherited disease mutations
Authors: Feldman Igor , Rzhetsky Andrey , Vitkup Dennis
Published: March 2008

By analyzing, in parallel, large literature-derived and high-throughput experimental datasets we investigate genes harboring human inherited disease mutations in the context of molecular interaction networks. Our results demonstrate that network properties influence the likelihood and phenotypic consequences of disease mutations. Genes with intermediate connectivities have the highest probability of harboring germ-line disease mutations, suggesting that disease genes tend to occupy an intermediate niche in terms of their physiological and cellular importance. Our analysis of tissue expression profiles supports this view. We show that disease mutations are less likely to occur in essential genes compared with all human genes. Disease genes display significant functional clustering in the analyzed molecular network. For about one-third of known disorders with two or more associated genes we find physical clusters of genes with the same phenotype. These clusters are likely to represent disorder-specific functional modules and suggest a framework for identifying yet-undiscovered disease genes.
Molecular mechanisms that control initiation and termination of physiological depolarization-evoked transmitter release
Authors: Kupchik Yonatan M. , Rashkovan Grigory , Ohana Lily , Keren-Raifman Tal , Dascal Nathan , Parnas Hanna , Parnas Itzchak
Published: March 2008

Ca
2+
is essential for physiological depolarization-evoked synchronous neurotransmitter release. But, whether Ca
2+
influx or another factor controls release initiation is still under debate. The time course of ACh release is controlled by a presynaptic inhibitory G protein-coupled autoreceptor (GPCR), whose agonist-binding affinity is voltage-sensitive. However, the relevance of this property for release control is not known. To resolve this question, we used pertussis toxin (PTX), which uncouples GPCR from its G
i/o
and in turn reduces the affinity of GPCR toward its agonist. We show that PTX enhances ACh and glutamate release (in mice and crayfish, respectively) and, most importantly, alters the time course of release without affecting Ca
2+
currents. These effects are not mediated by G
β
γ because its microinjection into the presynaptic terminal did not alter the time course of release. Also, PTX reduces the association of the GPCR with the exocytotic machinery, and this association is restored by the addition of agonist. We offer the following mechanism for control of initiation and termination of physiological depolarization-evoked transmitter release. At rest, release is under tonic block achieved by the transmitter-bound high-affinity presynaptic GPCR interacting with the exocytotic machinery. Upon depolarization, the GPCR uncouples from its G protein and consequently shifts to a low-affinity state toward the transmitter. The transmitter dissociates, the unbound GPCR detaches from the exocytotic machinery, and the tonic block is alleviated. The free machinery, together with Ca
2+
that had already entered, initiates release. Release terminates when the reverse occurs upon repolarization.
Mutations in the very low-density lipoprotein receptor
VLDLR
cause cerebellar hypoplasia and quadrupedal locomotion in humans
Authors: Ozcelik Tayfun , Akarsu Nurten , Uz Elif , Caglayan Safak , Gulsuner Suleyman , Onat Onur Emre , Tan Meliha , Tan Uner
Published: March 2008

Quadrupedal gait in humans, also known as Unertan syndrome, is a rare phenotype associated with dysarthric speech, mental retardation, and varying degrees of cerebrocerebellar hypoplasia. Four large consanguineous kindreds from Turkey manifest this phenotype. In two families (A and D), shared homozygosity among affected relatives mapped the trait to a 1.3-Mb region of chromosome 9p24. This genomic region includes the
VLDLR
gene, which encodes the very low-density lipoprotein receptor, a component of the reelin signaling pathway involved in neuroblast migration in the cerebral cortex and cerebellum. Sequence analysis of
VLDLR
revealed nonsense mutation R257X in family A and single-nucleotide deletion c2339delT in family D. Both these mutations are predicted to lead to truncated proteins lacking transmembrane and signaling domains. In two other families (B and C), the phenotype is not linked to chromosome 9p. Our data indicate that mutations in
VLDLR
impair cerebrocerebellar function, conferring in these families a dramatic influence on gait, and that hereditary disorders associated with quadrupedal gait in humans are genetically heterogeneous.
Mass spectrometry identifies and quantifies 74 unique histone H4 isoforms in differentiating human embryonic stem cells
Authors: Phanstiel Doug , Brumbaugh Justin , Berggren W. Travis , Conard Kevin , Feng Xuezhu , Levenstein Mark E. , McAlister Graeme C. , Thomson James A. , Coon Joshua J.
Published: March 2008

Epigenetic regulation through chromatin is thought to play a critical role in the establishment and maintenance of pluripotency. Traditionally, antibody-based technologies were used to probe for specific posttranslational modifications (PTMs) present on histone tails, but these methods do not generally reveal the presence of multiple modifications on a single-histone tail (combinatorial codes). Here, we describe technology for the discovery and quantification of histone combinatorial codes that is based on chromatography and mass spectrometry. We applied this methodology to decipher 74 discrete combinatorial codes on the tail of histone H4 from human embryonic stem (ES) cells. Finally, we quantified the abundances of these codes as human ES cells undergo differentiation to reveal striking changes in methylation and acetylation patterns. For example, H4R3 methylation was observed only in the presence of H4K20 dimethylation; such context-specific patterning exemplifies the power of this technique.
Splicing mediates the activity of four putative cellular internal ribosome entry sites
Authors: Baranick Brian T. , Lemp Nathan A. , Nagashima Jill , Hiraoka Kei , Kasahara Noriyuki , Logg Christopher R.
Published: March 2008

A growing number of cellular mRNAs are thought to possess internal ribosome entry sites (IRESs), sequences that permit translation of a transcript independent of its 5′ end and cap structure. Although dicistronic assays are the canonical method of testing sequences for IRES activity, they may produce false-positive results if unanticipated monocistronic RNAs arise from the dicistronic construct used. Using a dicistronic reporter system and a green fluorescent protein-tagged retrovirus to evaluate six previously reported cellular IRESs, we found that four contain 3′ splice sites whose activity was required for apparent IRES function and which resulted in formation of monocistronic transcripts by splicing. Bioinformatic analysis revealed that the 3′ splice sites identified in three of these putative IRESs are used in their native mRNAs and that the fourth is likely an artifactual sequence created during cDNA cloning. Our findings demonstrate a need for reexamination of other reported cellular IRESs by using careful RNA structural analysis to rule out splicing as the source of perceived IRES activity.
Contribution of positively charged flanking residues to the insertion of transmembrane helices into the endoplasmic reticulum
Authors: Lerch-Bader Mirjam , Lundin Carolina , Kim Hyun , Nilsson IngMarie , von Heijne Gunnar
Published: March 2008

Positively charged residues located near the cytoplasmic end of hydrophobic segments in membrane proteins promote membrane insertion and formation of transmembrane α-helices. A quantitative understanding of this effect has been lacking, however. Here, using an
in vitro
transcription–translation system to study the insertion of model hydrophobic segments into dog pancreatic rough microsomes, we show that a single Lys or Arg residue typically contributes approximately −0.5 kcal/mol to the apparent free energy of membrane insertion (Δ
G
app
) when placed near the cytoplasmic end of a hydrophobic segment and that stretches of 3–6 Lys residues can contribute significantly to Δ
G
app
from a distance of up to ≈13 residues away.
Production and sequence validation of a complete full length ORF collection for the pathogenic bacterium
Vibrio cholerae
Authors: Rolfs Andreas , Montor Wagner R. , Yoon Sang Sun , Hu Yanhui , Bhullar Bhupinder , Kelley Fontina , McCarron Seamus , Jepson Daniel A. , Shen Binghua , Taycher Elena , Mohr Stephanie E. , Zuo Dongmei , Williamson Janice , Mekalanos John , LaBaer Joshua
Published: March 2008

Cholera, an infectious disease with global impact, is caused by pathogenic strains of the bacterium
Vibrio cholerae
. High-throughput functional proteomics technologies now offer the opportunity to investigate all aspects of the proteome, which has led to an increased demand for comprehensive protein expression clone resources. Genome-scale reagents for cholera would encourage comprehensive analyses of immune responses and systems-wide functional studies that could lead to improved vaccine and therapeutic strategies. Here, we report the production of the FLEXGene clone set for
V. cholerae O1 biovar eltor str. N16961
: a complete-genome collection of ORF clones. This collection includes 3,761 sequence-verified clones from 3,887 targeted ORFs (97%). The ORFs were captured in a recombinational cloning vector to facilitate high-throughput transfer of ORF inserts into suitable expression vectors. To demonstrate its application, ≈15% of the collection was transferred into the relevant expression vector and used to produce a protein microarray by transcribing, translating, and capturing the proteins
in situ
on the array surface with 92% success. In a second application, a method to screen for protein triggers of Toll-like receptors (TLRs) was developed. We tested
in vitro
-synthesized proteins for their ability to stimulate TLR5 in A549 cells. This approach appropriately identified FlaC, and previously uncharacterized TLR5 agonist activities. These data suggest that the genome-scale, fully sequenced ORF collection reported here will be useful for high-throughput functional proteomic assays, immune response studies, structure biology, and other applications.