bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature drop turbidimetry as a means for the rapid determination of the polydispersities of polymers: Polystyrene
Authors: Afifi‐Effat A. M. , Hay J. N. 
Published: March 2007

AbstractThe molecular weight distributions of fractionated and unfractionated polystyrene samples were determined from turbidimetric data obtained by controlled precipitation from dilute solutions in cyclohexanol by cooling from 90 to 20°C. Estimates of the distributions were obtained by calibration of the temperatures of onset of precipitation and the weight average molecular weight of the polymer in solution, as suggested by Shultz,1 and correcting for the concentration change on precipitation.
Flexible relaxation of rigid‐body docking solutions
Authors: Król Marcin , Tournier Alexander L. , Bates Paul A. 
Published: March 2007

AbstractMolecular Dynamics (MD) simulations have been performed on a set of rigid‐body docking poses, carried out over 25 protein–protein complexes. The results show that fully flexible relaxation increases the fraction of native contacts (NC) by up to 70% for certain docking poses. The largest increase in the fraction of NC is observed for docking poses where anchor residues are able to sample their bound conformation. For each MD simulation, structural snap‐shots were clustered and the centre of each cluster used as the MD‐relaxed docking pose. A comparison between two energy‐based scoring schemes, the first calculated for the MD‐relaxed poses, the second for energy minimized poses, shows that the former are better in ranking complexes with large hydrophobic interfaces. Furthermore, complexes with large interfaces are generally ranked well, regardless of the type of relaxation method chosen, whereas complexes with small hydrophobic interfaces remain difficult to rank. In general, the results indicate that current force‐fields are able to correctly describe direct intermolecular interactions between receptor and ligand molecules. However, these force‐fields still fail in cases where protein–protein complexes are stabilized by subtle energy contributions. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Quantum‐chemical examination of interaction of cytostatic‐fluorouracil with deoxyribonucleic acids
Authors: Yuldasheva Gulnara , Zhidomirov Georgii M. 
Published: March 2007

AbstractWithin the framework of semiempirical method of quantum chemical PM3, the possibility of formation of paired stack structures under interaction of fluorouracil with pyrimidine and purine nitrogenous bases of nucleotides has been examined. Possible mechanism of transformation of 2‐deoxyuridine‐5‐monophosphate into metabolite‐5‐fluorin‐2‐deoxyuridine‐5‐monophosphate has been given. The calculations that were made allow to suppose that biotransformation of 5‐FU in 5‐fluorin‐2‐deoxyuridine‐5‐monophosphate, most likely, is carried out not in free nucleotides, but in the structure of DNA in two nucleotide triplets UUC and UGU, including the case when directly two nucleotides of deoxyuridine monophosphate, are transformed into 5‐fluorin‐2‐deoxyuridine‐5‐monophosphate. Cytostatic ability of 5‐FU is increased by its capacity to be selectively embedded into nucleotide triplets creating new chemical compounds that violate matrix RNA formation and accordingly violate protein synthesis. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Reaction mechanism of platinum dimer cation with ammonia based on the relativistic density functional study
Authors: Xu Dan , Chen Xian‐Yang , Wang Shu‐Guang 
Published: March 2007

AbstractThe gas‐phase reactions between Pt and NH3 have been investigated using the relativistic density functional approach (ZORA‐PW91/TZ2P). The quartet and doublet potential energy surfaces of Pt + NH3 have been explored. The minimum energy reaction path proceeds through the following steps: Pt(4Σu) + NH3 → q‐1 → d‐2 → d‐3 → d‐4 → d‐Pt2NH+ + H2. In the whole reaction pathway, the step of d‐2 → d‐3 is the rate‐determining step with a energy barrier of 36.1 kcal/mol, and exoergicity of the whole reaction is 12.0 kcal/mol. When Pt2NH+ reacts with NH3 again, there are two rival reaction paths in the doublet state. One is degradation of NH and another is loss of H2. In the case of degradation of NH, the activation energy is only 3.4 kcal/mol, and the overall reaction is exothermic by 8.9 kcal/mol. Thus, this reaction is favored both thermodynamically and kinetically. However, in the case of loss of H2, the rate‐determining step's energy barrier is 64.3 kcal/mol and the overall reaction is endothermic by 8.5 kcal/mol, so it is difficult to take place. Predicted relative energies and barriers along the suggested reaction paths are in reasonable agreement with experimental observations. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Net charge and polarizability of zeolitic Brønsted acidic sites
Authors: Torrens F. , Castellano G. 
Published: March 2007

AbstractThe interacting induced‐dipoles polarization model, implemented in our program POLAR, is used for the calculation of the effective polarizability of the zeolitic bridged OH group, which results much higher than that of the free silanol group. A high polarizability is also calculated for the bridged OH group with a Si4+, in the absence of Lewis‐acid promotion of silanol by Al3+. The crystal polarizability is estimated from the Clausius‐Mossotti relationship. Siliceous zeolites are low‐permittivity isolators. The interaction of a weak base with the zeolitic OH can be considered as a local bond. Only when cations are located in the zeolite micropore, next to tetrahedra that contain trivalent cations, are large electrostatic fields generated. They are short ranged, and the positive cation charges are compensated. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Time evolution of the Neel state
Authors: Soluyanov A. A. , Zagoulaev S. N. , Abarenkov I. V. 
Published: March 2007

AbstractA quasionedimentional spin chain s = ½ is considered as a lattice consisting of two sublattices. The attention is paid to the states, which are pure spin states of the whole lattice and both sublattices, the value of the sublattices' spins being maximum. It is shown that the Neel state can be considered as a superposition of such states. The exact equation for this superposition coefficients is developed. The possibility of the Neel state to be the eigenstate of a Hamiltonian is discussed. Several model Hamiltonians are examined, the well known ones and few novel Hamiltonians being considered. The time evolution of the Neel state in different models is studied with the help of Fock‐Krylov method. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
A Calorimetric Study of the Interaction between Waxy Maize Starch and Lipid
Authors: Abu‐Hardan Madian O. , Hill Sandra E. , Farhat Imad A. 
Published: March 2007

AbstractThere is considerable debate on the definition and measurement of the amount of amylose in starch and whether hydrophobic ligands can form a complex with amylopectin. One method for amylose determination is through the measurement of amylose‐lipid complexation using differential scanning calorimetry (DSC), with the assumption that amylopectin cannot form such a complex. As the sensitivity and methodologies used for DSC improves, the validity of this assumption needs to be tested once again. For the experimental work, α‐L‐lysophosphatidylcholine (LPC, 10% of starch dry weight) was used as the complexing agent and waxy maize starch. Optimisation of the DSC included changing the heating rate from 10ºC/min to 40ºC/min, which resulted in a higher sensitivity enabling the recording of an endotherm associated with the dissociation of a starch‐LPC complex. The observation of the endothermic formation of such complex could only be achieved when a microcalorimeter, which analyses a much larger sample than a standard calorimeter (190 mg of dry starch compared to 13 mg) was used. There are two possible interpretations for these observations: Either waxy maize starch contains traces of amylose (~ 0.5‐0.7%) and the DSC is sufficiently sensitive to detect these amounts or the α‐1,6 glucan long branches of waxy maize starch bind linear aliphatic compounds.
Pilot‐plant fractionation of cottonseed. I. Disintegration of cottonseed meats
Authors: Spadaro J. J. , Persell R. M. , Murphey C. H. , Vix H. L. E. , McCourtney E. J. , Hecker J. L. , Pollard E. F. , Gastrock E. A. 
Published: March 2007

AbstractDisintegration of cottonseed meats is an important unit operation in the cottonseed fractionation process. The results of tests utilizing a high‐speed, “dissolver‐type” impeller for disintegration by liquid shear are presented including curves to show the effect of moisture, hulls, solvents, peripheral speed, etc.Over 90% of through‐80‐mesh material can be obtained. Moisture content over 5% appreciably reduced the efficiency and increased power consumption and the viscosity of the slurry. Whole flakes resulted in a finer end product than flakes pre‐pulverized in the dry state. It was found that the presence of hulls slightly increased disintegration, power consumption, and viscosity; that higher speeds (up to 6,000 FPM peripheral speed) were more efficient; and that the effect of solvents was small.
The effect of shortening stability on commercially produced army ration biscuits. II. Development of oxidation during storage
Authors: Stevens Harold H. , Thompson John B. 
Published: March 2007

SummaryThe comparative rates of oxidation of the shortening in 22 lots of biscuits held under three different conditions of packaging at two different storage temperatures have been discussed. Relating stability tests to storage tests is practically impossible considering the numerous conditions of storage which might be encountered. Accelerated tests, however, are valuable for comparative purposes.Considering only the development of “rancidity”, a 100‐hour shortening appears to be adequate protection up to 12 months of storage at a maximum temperature of 100o F. for either Type I or Type IV Army ration biscuits when stored in either sealed cans or adequate breather‐type containers.The poor storage life of Army ration biscuits, packaged in fiberboard containers, was shown to be due primarily to the nature of the packaging material.Insofar as Army ration biscuits are concerned, the addition of N.D.G.A. to lard does not result in a significant increase in biscuit stability.
Chinese tallow nut protein. I. Isolation, amino acid, and vitamin analysis
Authors: Holland Bryant R. , Meinke W. W. 
Published: March 2007

ConclusionThe protein of the Chinese tallow nut is quite easily isolated by employing rather mild conditions. On the basis of amino acid values presented, both the protein and flour should be suitable as a protein feed. The relatively low lysine and methionine content however would limit the usefulness of the protein as a supplement to cereal grains. The relatively high thiamin content of the protein, in addition to the presence of smaller amounts of the other B vitamins determined, suggests the possible use of this material in the enrichment of flour for the baking industry. The industrial possibilities in addition to the food value of the protein are yet to be determined.
Fatty acids from the scent glands of the Louisiana muskrat
Authors: Erickson J. L. E. , Hix Homer B. 
Published: March 2007

Summary

The mixture of fatty acids from muskrat scent glands has been analyzed by the ester fractionation method.

The esters of myristic, palmitic, hexadecenoic, oleic, and linoleic acids were found present as major components in these glands. Unsaturated acids of the C24 and C26 series are also present to the extent of 8.5% of the total fatty acids. Acids present to less than 1% each include decanoic, dodecanoic, stearic, tetracosanoic, dodecenoic, and tetradecenoic acids.

Application of determinants for the solution of simultaneous equations has been presented as a method which greatly simplifies and facilitates the calculations necessary to this type of work.

The possible relationship existing between fatty acids and macrocyclic carbinols has been considered and possible mechanisms for such transformations have been presented.
Application of the antimony trichloride‐spectrophotometric method to the determination of gossypol in cottonseed and cottonseed products
Authors: Hall Catherine M. , Castillon Leah E. , Guice Wilma A. , Boatner Charlotte H. 
Published: March 2007

SummaryA method is described which permits application of the antimony trichloride spectrophotometric method to the determination of gossypol in a variety of cottonseed products.Gossypol is determined by means of the following series of operations: 1. extraction of gossypol from cottonseed or cottonseed products by use of chloroform or aqueous ethanol; 2. isolation of gossypol from the extracts by use of aqueous alkali; and 3. application of the antimony trichloride‐spectrophotometric test.Data are presented to show the results obtained by application of this procedure to the determination of gossypol in pigment glands, raw cottonseed meats, cooked cottonseed meats, hydraulic‐ and screw‐pressed meals, solvent‐extracted meals, gland‐free meals, and oils, both expressed and solvent‐extracted.
Effects of positive youth development programs on school, family, and community systems
Authors: Durlak Joseph A. , Taylor Rebecca D. , Kawashima Kei , Pachan Molly K. , DuPre Emily P. , Celio Christine I. , Berger Sasha R. , Dymnicki Allison B. , Weissberg Roger P. 
Published: March 2007

AbstractA review of efforts at social system change in 526 universal competence‐promotion outcome studies indicated that 64% of the interventions attempted some type of microsystemic or mesosystemic change involving schools, families, or community‐based organizations in an attempt to foster developmental competencies in children and adolescents. Only 24% of the reports provided quantitative data on the change that occurred in targeted systems. However, studies containing the necessary information produced several mean effect sizes that were statistically significant, and ranged from modest to large in magnitude. These data indicate that attempts to change social systems affecting children and adolescents can be successful. Future work should measure more thoroughly the extent to which the systemic changes that are targeted through intervention are achieved, and investigate how such changes contribute to the development and sustainability of the outcomes that might be demonstrated by participants of competence‐promotion programs.
Under-reporting of notifiable infectious disease hospitalizations in a health board region in Ireland: room for improvement?
Authors: BRABAZON E. D. , O'FARRELL A. , MURRAY C. A. , CARTON M. W. , FINNEGAN P. 
Published: March 2007

SUMMARYRapid notification of infectious diseases is essential for prompt public health action and for monitoring of these diseases in the Irish population at both a local and national level. Anecdotal evidence suggests, however, that the occurrence of notifiable infectious diseases is seriously underestimated. This study aims to assess the level of hospitalization for notifiable infectious diseases for a 6-year period in one health board region in Ireland and to assess whether or not there was any under-reporting during this period. All hospital in-patient admissions from 1997 to 2002 inclusive with a principal diagnosis relating to ‘infectious and parasitic diseases’ (ICD codes 001–139) of residents from a health board region in Ireland were extracted from the Hospital In-Patient Enquiry System (HIPE). All notifiable infectious diseases were identified based on the 1981 Irish Infectious Disease Regulations and the data were analysed in the statistical package, JMP. These data were compared with the corresponding notification data. Analysis of the hospital in-patient admission data revealed a substantial burden associated with notifiable infectious diseases in this health board region: there were 2758 hospitalizations by 2454 residents, 17 034 bed days and 33 deaths. The statutory notification data comprises both general practitioner and hospital clinician reports of infectious disease. Therefore, only in cases where there are more hospitalizations than notifications can under-reporting be demonstrated. This occurred in nine out of 22 notifiable diseases and amounted to an additional 18% of notifications (or 572 cases) which were ‘missed’ due to hospital clinician under-reporting. The majority of these under-reported cases were for viral meningitis (45%), infectious mononucleosis (27%), viral hepatitis C unspecified (15%) and acute encephalitis (5·8%). This study has highlighted the extent of under-reporting of hospitalized notifiable infectious diseases, in a health board region in Ireland, which is a cause for concern from a surveillance point of view. If this under-reporting is similar in other health boards, then it would appear that the epidemiology of some notifiable diseases is incomplete both regionally and nationally. This under-reporting negatively impacts on the effectiveness of the notification process as a ‘real-time’ surveillance tool and an early warning system for outbreaks.
Linking syndromic surveillance with virological self-sampling
Authors: COOPER D. L. , SMITH G. E. , CHINEMANA F. , JOSEPH C. , LOVERIDGE P. , SEBASTIONPILLAI P. , GERARD E. , ZAMBON M. 
Published: March 2007

SUMMARYCalls to a UK national telephone health helpline (NHS Direct) have been used for syndromic surveillance, aiming to provide early warning of rises in community morbidity. We investigated whether self-sampling by NHS Direct callers could provide viable samples for influenza culture. We recruited 294 NHS Direct callers and sent them self-sampling kits. Callers were asked to take a swab from each nostril and post them to the laboratory. Forty-two per cent of the samples were returned, 16·2% were positive on PCR for influenza (16 influenza A(H3N2), three influenza A (H1N1), four influenza B) and eight for RSV (5·6%). The mean time between the NHS Direct call and laboratory analysis was 7·4 days. These samples provided amongst the earliest influenza reports of the season, detected multiple influenza strains, and augmented a national syndromic surveillance system. Self-sampling is a feasible method of enhancing community-based surveillance programmes for detection of influenza.
The prehistory of panspermia: astrophysical or metaphysical?
Authors: Temple Robert 
Published: March 2007

AbstractThe panspermia theory has antecedents which go back to the Old Kingdom in Egypt, and which are also found in early Hinduism, the philosophy of the Greek pre-Socratic philosopher Anaxagoras, and amongst the Jewish and Christian Gnostics. It is remarkable how explicit some of these early sources are in suggesting that the entire cosmos is full of seeds, and that life on earth originated from them. Here, a survey is undertaken of all these early beliefs, in order to present a pre-history to these conceptions and show that such ideas appear to be as old as civilization itself.
Curve of amniotic fluid index measurements in low‐risk pregnancy
Authors: REGINA MACHADO MARIA , GUILHERME CECATTI JOSE , KRUPA FABIANA , FAUNDES ANIBAL 
Published: March 2007

AbstractObjectives. To establish a curve of amniotic fluid index [AFI] measurements from the 20th to the 42nd week of pregnancy. Methods. A prospective and descriptive study was performed, in which an independent sample of 2,868 low‐risk pregnant women were studied using routine ultrasound, including fetal biometry and measurement of AFI. Data were analysed using multiple linear regression, and constructing a curve using 2.5th, 10th, 50th, 90th and 97.5th percentiles of the AFI measurements, according to gestational age, and after submitting values to smoothing process using quadratic polynomial adjustment. Results. There was a significant variation in AFI measurements at the different gestational ages. The 50th percentile remained practically constant at approximately 150 mm between the 20th and 33rd week, after which there was a decline in volume, which became evident after the 38th week. At the 40th week, the 10th percentile was around 62 mm and the 2.5th percentile around 33 mm. Conclusions. The curve of percentiles of AFI measurements in low‐risk pregnant women showed significant decrease with gestational age, especially after the 33rd week. These data should be validated for a diagnosis of increased or decreased volumes of amniotic fluid at specific gestational ages.
Attempted vaginal versus planned cesarean delivery in 195 breech first twin pregnancies
Authors: SENTILHES LOÏC , GOFFINET FRANÇOIS , TALBOT ALAIN , DIGUET ALAIN , VERSPYCK ERIC , CABROL DOMINIQUE , MARPEAU LOÏC 
Published: March 2007

AbstractBackground. To compare neonatal and maternal outcomes for breech first twins according to whether vaginal or cesarean delivery was planned and to verify that in appropriate selected cases, attempted vaginal delivery is a reasonable choice. Methods. A retrospective study of all twin pregnancies with the first twin in breech position and gestational age at least 35 weeks at birth at two French university hospital centers from January 1994 through December 2000. The primary outcome was a combined indicator of neonatal mortality and severe morbidity, as defined by one or more of the following: death before discharge, admission to neonatal intensive care unit, 5‐minute Apgar score <7, cord blood pH <7.10, or birth trauma. Results. Cesarean delivery was planned for 71 (36.4%) patients, and attempted vaginal delivery for 124 (63.6%), 59 (47.6%) of whom were delivered vaginally and 65 (52.4%) by cesarean during labor. Neither the combined negative outcome indicator nor neonatal mortality differed significantly for either twin or either group. There were no significant differences in maternal mortality or morbidity between the two groups. The frequency of deep vein thrombophlebitis or pulmonary embolism requiring anticoagulant therapy was significantly higher in the planned cesarean group [3/71 (4.2%) versus 0/124; p = 0.047]. Conclusion. When appropriate criteria are used to decide mode of delivery, a careful intrapartum protocol is followed, and an experienced obstetrician, midwife, and anesthesiologist are in attendance, attempted vaginal delivery is a reasonable option for first twins in breech position.
Does group training during pregnancy prevent lumbopelvic pain? A randomized clinical trial
Authors: MØRKVED SIV , Salvesen Kjell Åsmund , SCHEI BERIT , LYDERSEN STIAN , BØ KARI 
Published: March 2007

AbstractBackground. Prevention of lumbopelvic pain in pregnancy has been sparsely studied. One aim of this study was to assess if a 12‐week training program during pregnancy can prevent and/or treat lumbopelvic pain. A randomized controlled trial was conducted at Trondheim University Hospital and three outpatient physiotherapy clinics. Three hundred and one healthy nulliparous women were included at 20 weeks of pregnancy and randomly allocated to a training group (148) or a control group (153). Methods. The outcome measures were self‐reported symptoms of lumbopelvic pain (once per week or more), sick leave, and functional status. Pain drawing was used to document the painful area of the body. The intervention included daily pelvic floor muscle training at home, and weekly group training over 12 weeks including aerobic exercises, pelvic floor muscle and additional exercises, and information related to pregnancy. Results. At 36 weeks of gestation women in the training group were significantly less likely to report lumbopelvic pain: 65/148 (44%) versus 86/153 (56%) (p = 0.03). Three months after delivery the difference was 39/148 (26%) in the training group versus 56/153 (37%) in the control group (p = 0.06). There was no difference in sick leave during pregnancy, but women in the training group had significantly (p = 0.01) higher scores on functional status. Conclusions. A 12‐week specially designed training program during pregnancy was effective in preventing lumbopelvic pain in pregnancy.