bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal unfolding of proteins probed by laser spray mass spectrometry
Authors: Shi Xiangguo , Takamizawa Atsushi , Nishimura Yoshifumi , Hiraoka Kenzo , Akashi Satoko 
Published: April 2008

AbstractThe stability and conformational changes of cytochrome c (cyt c) at different temperatures and pH have been well examined so far by using various analytical methods. We have found that laser spray mass spectrometry enables much faster and more convenient monitoring of those changes of cyt c compared with other methods. The results correlated well with circular dichroism (CD) experiments under relatively acidic conditions, which destabilize the protein. Laser spray mass spectra of cyt c at various pH were obtained at different levels of laser power. Bimodal charge‐state distributions of the protein were observed in laser spray mass spectra, indicating the two‐state model of structural change; the lower charges correspond to the folded state, the higher charges to the unfolded state. Based on this result, the presumed denaturation curve of the protein was plotted as a function of laser power, and laser power by which 50% of the protein was assumed to be denatured, E50%, as obtained at each pH. We also examined the melting temperatures, Tm, of cyt c at various values of pH by using CD spectroscopy. The correlation coefficient between E50% and Tm for cyt c was 0.999, demonstrating an excellent correlation. Furthermore, laser spray analysis of ubiquitin, which is found to be more thermally stable than cyt c, gave a higher E50% than cyt c. These results indicate that laser spray mass spectrometry can be an extremely convenient method for probing thermal stabilities and dynamic conformational changes of proteins with subtle structural differences caused by slight changes in pH. Copyright © 2008 John Wiley & Sons, Ltd.
Adaptive control design for a class of nonsmooth nonlinear systems with matched and linearly parameterized uncertainty
Authors: Nakakuki Takashi , Shen Tielong , Tamura Katsutoshi 
Published: April 2008

AbstractThis paper presents an adaptive control design for a class of nonsmooth nonlinear systems with matched uncertainty, which is linearly parameterized with a known discontinuous function. The design framework is based on the concept of the Filippov solution as the classical Lyapunov theory for smooth systems cannot be applied to establish the stability of the adaptive control system due to the presence of the discontinuity. It is proved that as an adaptive control system, the global Lyapunov stability with the convergence of the state of the controlled system to the origin can be achieved by evaluating the monotonicity of the Lyapunov function in the state space, particularly on the discontinuous surface, while the uniqueness of the solution of the closed‐loop system is not necessarily guaranteed. Some interesting numerical examples are demonstrated with simulation results. Copyright © 2008 John Wiley & Sons, Ltd.
Equivalent chain lengths of methyl octadecadienoates and octadecatrienoates
Authors: Scholfield C. R. , Dutton H. J. 
Published: April 2008

AbstractEquivalent chain lengths (ECL) have been determined for a number of methyl octadecadienoates and octadecatrienoates with different stationary phases, including Apiezon L, polyphenyl ether, diethylene glycol succinate, XF 1150, 100% cyanoethyl silicone and tetracyanoethylated pentaerythritol. ECL values for unconjugated esters are slightly larger than calculated by adding the ECL increments over stearate found for octadecenoates with the same position and configuration of double bonds. In general, differences are greater for methylene‐interrupted double bonds and fortrans double bonds. They are greater for more polar columns. Average corrections can be added so that calculated ECL values agree well with the determined values. ECL increases with polarity of the stationary phase. The relative ECL pattern on different stationary phases changes little with position of double bonds in the isomers, but it is affected by double bond configuration. For esters with the same double bond positions isomers withtrans double bonds tend to have lower ECL values thancis on polar stationary phases and higher ECL values on nonpolar. ECL’s of conjugated octadecadienoates are always higher than unconjugated and increase in the ordercis,cis; mono‐trans; andtrans,trans.
Alkyl azelaaldehydates of high purity from alkyl soyates: Preparation and properties
Authors: Awl R. A. , Pryde E. H. , Weisleder D. , Rohwedder W. K. , Cowan J. C. 
Published: April 2008

AbstractReductive ozonolysis of appropriate alkyl soyates in various participating media producted methyl, ethyl,n‐propyl, isopropyl andn‐butyl azelaaldehydates in good yield and high purity (98+%). The participating media examined were: methyl, ethyl,n‐propyl andn‐butyl alcohols; mixtures of an alcohol and acetic acid; water; and mixtures of water and acetic acid. Any combination of solvent and ester, except methanol‐methyl soyate, allowed good separation by fractional distillation of ester and acetal impurities from the azelaaldehydate. A preparative method was developed by which high purity ethyl azelaaldehydate is produced from soybean oil by reductive ozonolysis in water. The only major impurity by this method was ethyl hydrogen azelate, which was easily removed with a bicarbonate wash. After a single fractional distillation with a short Vigreux column, the azelaaldehydate was obtained in 78% yield and 98+% purity. Physical properties and spectral (IR, NMR and mass spectroscopy) and chromatographic data were determined for the pure alkyl azelaaldehydates. Several of these properties were also determined for acetal and diester byproducts.
A rapid screening technique for determining the lipid composition of soybean seeds
Authors: Dahmer Mark L. , Fleming Pierce D. , Collins Glenn B. , Hildebrand David F. 
Published: April 2008

AbstractAn efficient method to determine the fatty acid composition of a large number of small seed tissue samples is needed to facilitate the genetic manipulation of seed lipid composition in soybean and other oilseeds. A rapid procedure has been developed to simultaneously extract and transmethylate the neutral lipids from soybean cotyledons at 90°C in a mixture of hexane and 1% H2SO4 in methanol (pretreatment of cotyledon pieces with hexane prior to methanolysis was found to improve yields). Fatty acid methyl esters were analyzed by capillary or packed column gas chromatography. The method required less than 10 mg of cotyledon tissue which could be taken from opposite the embryo axis so the sampled seed remained viable.This direct transmethylation method was compared to Soxhlet extraction and subsequent acid methanolysis and to methods requiring separate steps for extraction [with hexane alone, hexane:isopropanol (3:2) or chloroform:methanol (2:1)], washing, solvent removal and methanolysis. Determinations of fatty acid content and composition were similar among the four methods. Approximately 30 times more samples could be analyzed (more than 2000 samples per month) using the direct transesterification method than were possible with the Soxhlet procedure. This direct transmethylation method is more rapid, requires less tissue, and provides results comparable to other inexpensive methods. It should be especially useful in breeding studies where large numbers of small samples are encountered.
The extraction of natural cashew nut‐shell liquid from the cashew nut (Anacardium occidentale)
Authors: Tyman J. H. P. , Johnson R. A. , Muir M. , Rokhgar R. 
Published: April 2008

AbstractIn the two‐stage recovery of natural cashew nut‐shell liquid (CNSL) by solvent extraction, the overall yields from half‐shells obtained by mechanical cutting and from chilled fragmented shells (to solidify the phenols) by manual processing are identical, indicating that no physical loss of phenolic material occurs in the mechanical process. At the first stage, prior to comminution, the yield from intact half‐shells of mechanical origin is considerably less than that from manually processed shells due to extensive internal fracturing of the shell structure and greater solvent penetration in the latter case. Static solvent extraction of macerated shells gave the same yield as Soxhlet extraction, but the filtration stage was difficult and large volumes of solvent were required. Soxhlet solvent extraction or ultrasound/solvent extraction of manually processed shells at ambient temperature gave similar yields and economy in solvent usage. Both were much superior to mechanical agitation. By catalyzed decarboxylation of the recovered natural CNSL an almost theoretical yield (25%) of phenolic lipid rich in cardanol was obtained, which is considerably higher than that (10%) in the traditional recovery of technical CNSL by the hot oil bath industrial method. Natural CNSL contains a predominant amount of anacardic acid and represents a novel phenolic lipid source. Chemical reduction with air/aqueous hydrazine gave saturated natural CNSL. Polymerization of natural CNSL was effected in alkaline solution with paraformaldehyde.
Hepatic cirrhosis, dystonia, polycythaemia and hypermanganesaemia—A new metabolic disorder
Authors: Tuschl Karin , Mills Philippa B. , Parsons Howard , Malone Marian , Fowler Darren , Bitner‐Glindzicz Maria , Clayton Peter T. 
Published: April 2008

SummaryWe report a new constellation of clinical features consisting of hypermanganesaemia, liver cirrhosis, an extrapyramidal motor disorder and polycythaemia in a 12 year‐old girl born to consanguineous parents. Blood manganese levels were >3000 nmol/L (normal range <320 nmol/L) and MRI revealed signal abnormalities of the basal ganglia consistent with manganese deposition. An older brother with the same phenotype died at 18 years, suggesting a potentially lethal, autosomal recessive disease. This disorder is probably caused by a defect of manganese metabolism with the accumulation of manganese in the liver and the basal ganglia similar to the copper accumulation in Wilson disease. In order to assess the genetic basis of this syndrome we investigated two candidate genes: ATP2C2 and ATP2A3 encoding the manganese‐transporting calcium‐ATPases, SPCA2 and SERCA3, respectively. Genotyping of the patient and the family for microsatellite markers surrounding ATP2C2 and ATP2A3 excluded these genes. The patient was found to be heterozygous for both gene loci. Despite the unknown pathophysiology, we were able to develop a successful treatment regime. Chelation therapy with disodium calcium edetate combined with iron supplementation is the treatment of choice, lowering blood manganese levels significantly and improving clinical symptoms.
AGAT, GAMT and SLC6A8 distribution in the central nervous system, in relation to creatine deficiency syndromes: A review
Authors: Braissant O. , Henry H. 
Published: April 2008

SummaryCreatine deficiency syndromes, either due to AGAT, GAMT or SLC6A8 deficiencies, lead to a complete absence, or a very strong decrease, of creatine within the brain, as measured by magnetic resonance spectroscopy. While the mammalian central nervous system (CNS) expresses AGAT, GAMT and SLC6A8, the lack of SLC6A8 in astrocytes around the blood–brain barrier limits the brain capacity to import creatine from the periphery, and suggests that the CNS has to rely mainly on endogenous creatine synthesis through AGAT and GAMT expression. This seems contradictory with SLC6A8 deficiency, which, despite AGAT and GAMT expression, also leads to creatine deficiency in the CNS. We present novel data showing that in cortical grey matter, AGAT and GAMT are expressed in a dissociated way: e.g. only a few cells co‐express both genes. This suggests that to allow synthesis of creatine within the CNS, at least for a significant part of it, guanidinoacetate must be transported from AGAT‐ to GAMT‐expressing cells, possibly through SLC6A8. This would explain the creatine deficiency observed in SLC6A8‐deficient patients. By bringing together creatine deficiency syndromes, AGAT, GAMT and SLC6A8 distribution in CNS, as well as a synthetic view on creatine and guanidinoacetate levels in the brain, this review presents a comprehensive framework, including new hypotheses, on brain creatine metabolism and transport, both in normal conditions and in case of creatine deficiency.
Reduction in bone mineral density in glycogenosis type III may be due to a mixed muscle and bone deficit
Authors: Mundy H. R. , Williams J. E. , Lee P. J. , Fewtrell M. S. 
Published: April 2008

SummaryGlycogen storage disease type III (GSD III; OMIM 232400) is an autosomal recessive deficiency of the glycogen debrancher enzyme, amylo‐1,6‐glucosidase (EC 3.2.1.33). Patients with other hepatic glycogenoses are known to have reduced bone mineral content (BMC) and to be at consequent risk of fractures. They have key metabolic differences from GSD III patients, however. This study examines bone density and metabolism in 15 GSD III patients (6 female) from childhood to adulthood (aged 10–34 years). The results demonstrate that patients with GSD III have low bone mass at all skeletal sites compared with healthy individuals of the same age and sex, with a significant proportion (40–64%) having BMD > 2 standard deviations below the mean for whole body and lumbar spine. The deficiency seems to be attributable to a mixed muscle andbone deficit. Lower bone mass was found at all sites for GSD IIIa patients (combined liver and muscle defect) compared with GSD IIIb patients (liver only defect). Conclusion: Patients with GSD III have significantly abnormal bone mass, placing them at increased risk of potential fracture. The underlying mechanism is probably multifactorial with contributions from abnormal muscle physiology, abnormal metabolic milieu and altered nutrition affecting micronutrient intake. Therapies need to address all these factors to be successful.
Sanfilippo syndrome: A mini‐review
Authors: Valstar M. J. , Ruijter G. J. G. , van Diggelen O. P. , Poorthuis B. J. , Wijburg F. A. 
Published: April 2008

SummaryMucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is an autosomal recessive disorder, caused by a deficiency in one of the four enzymes involved in the lysosomal degradation of the glycosaminoglycan heparan sulfate. Based on the enzyme deficiency, four different subtypes, MPS IIIA, B, C, and D, are recognized. The genes encoding these four enzymes have been characterized and various mutations have been reported. The probable diagnosis of all MPS III subtypes is based on increased concentration of heparan sulfate in the urine. Enzymatic assays in leukocytes and/or fibroblasts confirm the diagnosis and allow for discrimination between the different subtypes of the disease. The clinical course of MPS III can be divided into three phases. In the first phase, which usually starts between 1 and 4 years of age, a developmental delay becomes apparent after an initial normal development during the first 1–2 years of life. The second phase generally starts around 3–4 years and is characterized by severe behavioural problems and progressive mental deterioration ultimately leading to severe dementia. In the third and final stage, behavioural problems slowly disappear, but motor retardation with swallowing difficulties and spasticity emerge. Patients usually die at the end of the second or beginning of the third decade of life, although survival into the fourth decade has been reported. Although currently no effective therapy is yet available for MPS III, several promising developments raise hope that therapeutic interventions, halting the devastating mental and behavioural deterioration, might be feasible in the near future.
N‐3 Polyunsaturated Fatty Acids Modulate In‐Vitro T Cell Function in Type I Diabetic Patients
Authors: Merzouk Sid Ahmed , Saker Meriem , Reguig Karima Briksi , Soulimane Nassima , Merzouk Hafida , Guermouche Baya , Berrouiguet Abdelsslam Yahia , Hichami Aziz , Narce Michel , Khan Naim Akhtar 
Published: April 2008

AbstractIn this work, we assessed the in‐vitro effects of eicosapentaenoic acid (EPA; C20:5n‐3) and docosahexaenoic acid (DHA; C22:6n‐3) (final concentration, 15 μM) on T cell blastogenesis, interleukin‐2 and ‐4 (IL‐2, IL‐4) secretion, fatty acid composition and intracellular oxidative status in type I diabetic patients with or without complications. Con A stimulated lymphocyte proliferation, glucose uptake, intracellular reduced glutathione levels and catalase activity were lower in diabetics as compared to controls, regardless to the presence of complications. EPA and DHA diminished T‐lymphocyte proliferation and IL‐2 production but enhanced IL‐4 secretion in both diabetic and control groups. No changes in the levels of reduced glutathione and in the activities of catalase and SOD were observed in control T cells cultured in the presence of EPA and DHA. However, in diabetic patients, addition of n‐3 PUFA to culture induced an increase in T cell levels of reduced glutathione and hydroperoxide, and in activities of catalase and SOD. Low levels of arachidonic acid (C20:4n‐6) were found in plasma membrane phospholipids of lymphocytes from diabetic patients compared to controls. Incubation of lymphocytes with EPA and DHA was associated with an incorporation of these fatty acids in membrane phospholipids. In conclusion, the beneficial effects of n‐3 PUFA on T cell functions in type I diabetes could be attributed to their suppressive action and modulation of cytokine secretion, and to the improvement of intracellular oxidative status.
Norm convergence of multiple ergodic averages for commuting transformations
Authors: TAO TERENCE 
Published: April 2008

AbstractLet T1,…,Tl:X→X be commuting measure-preserving transformations on a probability space $(X, \mathcal {X}, \mu )$. We show that the multiple ergodic averages $\bfrac {1}{N} \sum _{n=0}^{N-1} f_1(T_1^n x) \cdots f_l(T_l^n x)$ are convergent in $L^2(X,\mathcal {X},\mu )$ as $N \to \infty $ for all $f_1,\ldots ,f_l \in L^\infty (X,\mathcal {X},\mu )$; this was previously established for l=2 by Conze and Lesigne [J. P. Conze and E. Lesigne. Théorèmes ergodique por les mesures diagonales. Bull. Soc. Math. France112 (1984), 143–175] and for general l assuming some additional ergodicity hypotheses on the maps Ti and TiTj−1 by Frantzikinakis and Kra [N. Frantzikinakis and B. Kra. Convergence of multiple ergodic averages for some commuting transformations. Ergod. Th. & Dynam. Sys.25 (2005), 799–809] (with the l=3 case of this result established earlier by Zhang [Q. Zhang. On the convergence of the averages $\bfrac {1}{N} \sum _{n=1}^N f_1(R^n x) f_2(S^n x) f_3(T^n x)$. Mh. Math.122 (1996), 275–300]). Our approach is combinatorial and finitary in nature, inspired by recent developments regarding the hypergraph regularity and removal lemmas, although we will not need the full strength of those lemmas. In particular, the l=2 case of our arguments is a finitary analogue of those by Conze and Lesigne.
Some Factors Affecting Response in Recognition Tests
Authors: Belbin Eunice , Cane Violet R. 
Published: April 2008

Experiments were designed to investigate some of the factors which might affect a subject's responses in a recognition test. Two experiments are described. In the first, subjects were shown 12 similar photographs. They were then given a recognition test of 12 photographs, of which a number varying from o to 12 had been shown in the original display. All the photographs were sufficiently alike to render some guessing essential. It was found that subjects tended to select approximately 50 per cent. as having been seen previously and to reject 50 per cent. When a second and similar display and recognition test followed immediately, there was a tendency for subjects to make more “yes” responses, without any improvement in accuracy. The effect of giving serial presentation first was to increase the number accepted not only in that test but also in a test using simultaneous presentation which succeeded it. It was also shown that when a correct decision was possible but difficult a positively correct response (in this case recognizing something seen before) was easier than a negatively correct one (rejecting something not seen before). In the second experiment subjects were shown a picture and were then asked to describe it from memory. Immediately afterwards half the group was given a multiple-choice recognition test while the other half was given a single-choice recognition test. It was found that accuracy and certainty of decision varied with the nature of the choice situation. The results are discussed in relation to a theory of adaptation levels.
“Handedness” and Skill
Authors: Provins K. A. 
Published: April 2008

The variability of handedness with different tasks is discussed. Experiments are described which show under what conditions handedness becomes evident. Tasks involving three different levels of complexity were used. The simplest task measured the accuracy with which a particular pressure could be reproduced in isometric contraction of the flexors of the index finger on each side in 21 female subjects. In the second situation, the maximum speed of making an attempted tapping movement under the same conditions, was measured in ten of the same subjects using the same muscle group alternating with its antagonists. The same ten subjects were also tested on an aiming task which provided the third level of complexity. The results suggest that differences in performance between the two sides only occur where “timing” or the serial organization of muscle activity is required and that such differences may be due to training. Whether handedness is inherited or acquired is briefly discussed, and a second series of experiments using the same tasks as before were carried out on one female and nine male subjects. In this instance, the first two tests were used on the big toe of each side as well as the index finger. The results confirm that differences in performance between the two sides on these tasks can be adequately explained in terms of usage or training. The hypothesis that “timing” is therefore important in the learning of any movement where serial muscle contractions arc involved was tested and confirmed in a third experimental series. The consistency of timing of the application of force in turning a crank handle at maximum speed was measured in five male subjects before and after training. The implications of the results are discussed in relation to other researches on skills.