bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure–volume–temperature of molten and glassy polymers
Authors: Utracki L. A. 
Published: December 2006

AbstractThe pressure–volume–temperature (PVT) dependencies of several amorphous polymers (PS, PC, PPE, and PPE/PS 1:1 blend) in the glassy and molten state were studied. The Simha–Somcynsky (S–S) lattice‐hole equation of state (EOS) was used. Fitting the PVT data in the molten state to the EOS yielded the free volume quantity, h = h(T, P), and the characteristic reducing parameters, P*, V*, and T*. The data within the glassy region were interpreted assuming that the latter parameters are valid in the molten and vitreous state, than calculating h = h(T, P) from the experimental values of V = V(T, P). Next, the frozen free volume fraction in the glass was computed as FF = FF(P). The FF values of polystyrene (PS) resins at ambient pressure showed little scattering (FFP=1 = 0.691 ± 0.008), while their P‐dependencies varied, reflecting the thermodynamic history of the glass formation as well as the PVT measurements protocol. The pressure gradient of Tg was compared with the Ehrenfest relation for the second‐order transition; here also agreement depended on the method of vitrification. The experimental values of FF at ambient pressure decreased with increasing values of the characteristic temperature reducing parameter, T*. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 270–285, 2007.
Partially pyrolyzed poly(dimethylsiloxane)‐based networks: Thermal characterization and evaluation of the gas permeability
Authors: José Nádia M. , de Almeida Prado Luis A. S. , Schiavon Marco A. , Redondo Simone U. A. , Yoshida Inez V. P. 
Published: December 2006

AbstractIn this investigation, the preparation and characterization of partially pyrolyzed membranes based on poly(dimethylsiloxane) (PDMS) are described. These membranes were obtained by the crosslinking of silanol‐terminated PDMS with multifunctional nanoclusters derived from the reaction of pentaerythritoltriacrylate with 2‐aminoethyl‐3‐aminopropyltrimethoxysilane and the in situ polycondensation of tetraethylortosilicate, followed by the thermal treatment of the resulting membranes at different temperatures. The partially pyrolyzed membranes were characterized with infrared spectroscopy, thermogravimetry, elemental analyses, dynamic mechanical analysis, small‐angle X‐ray scattering, and scanning electron microscopy. The membranes exhibited improvements in the thermal stability and mechanical strength. Even with distinct compositions with respect to the Si/O and Si/C ratios, the flexibility of these materials was maintained. The flux rates of the gases through the membranes were measured for N2, H2, O2, CH4, and CO2, at 25 °C. The permeability of the membranes changed with increases in the pyrolysis and oxidation temperatures. These membranes could be described as PDMS chains separated by inorganic clusters. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 299–309, 2007.
Assessing unmet supportive care needs in partners of cancer survivors: the development and evaluation of the Cancer Survivors' Partners Unmet Needs measure (CaSPUN)
Authors: Hodgkinson K. , Butow P. , Hobbs K. M. , Hunt G. E. , Lo S. K. , Wain G. 
Published: December 2006

AbstractBackground: Partners of cancer patients typically provide the majority of patients' emotional and physical care. Partners may be profoundly affected by the cancer and may experience ongoing supportive care needs across the survivorship continuum. Research has been restricted by a lack of psychometrically evaluated measures and in this study, a self‐report measure of partners' needs was developed and empirically evaluated.Methods: Questionnaire items generated from a qualitative study were constructed into a 47‐ item unmet need measure (Cancer Survivors' Partners Unmet Needs measure, CaSPUN). The psychometric properties of the CaSPUN were evaluated in 212 partners of patients who had been diagnosed with cancer 1–11 years earlier and were currently disease‐free.Results: The CaSPUN was modified to include 35 unmet need items, 6 positive change items and an open ended item. The CaSPUN demonstrates a high level of acceptability, internal consistency and construct validity, although test–retest reliability was moderate. Factor analysis identified five discrete factors: (1) Relationships, (2) Information, (3) Partner Issues, (4) Comprehensive Care and (5) Emotional Support.Conclusions: The CaSPUN permits the identification of long‐term supportive care needs in generic populations of cancer survivors' partners and will assist with the formulation of recommendations regarding required supportive care services. Copyright © 2006 John Wiley & Sons, Ltd.
Transformation of an α‐helix peptide into a β‐hairpin induced by addition of a fragment results in creation of a coexisting state
Authors: Araki Mitsugu , Tamura Atsuo 
Published: December 2006

AbstractIntrinsic rules of determining the tertiary structure of a protein have been unknown partly because physicochemical factors that contribute to stabilization of a protein structure cannot be represented as a linear combination of local interactions. To clarify the rules on the nonlinear term caused by nonlocal interaction in a protein, we tried to transform a peptide that has a fully helical structure (Target Peptide or TP) into a peptide that has a β‐hairpin structure (Designed Peptide or DP) by adding seven residues to the C terminus of TP. According to analyses of nuclear magnetic resonance measurements, while the β‐hairpin structure is stabilized in some DPs, it is evident that the helical structure observed in TP is also persistent and even extended throughout the length of the molecule. As a result, we have produced a peptide molecule that contains both the α‐helix and β‐hairpin conformation at an almost equally populated level. The helical structures contained in these DPs were more stable than the helix in TP, suggesting that stabilizing one conformation does not result in destabilizing the other conformation. These DPs can thus be regarded as an isolated peptide version of the chameleon sequence, which has the capability of changing the secondary structure depending on the context of the surrounding environment in a protein structure. The fact that the transformation of one secondary structure caused stabilization of both the original and the induced structure would shed light on the mechanism of protein folding. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Stabilization of an excess electron on molecular surfaces by a pair of HF molecules
Authors: Jalbout Abraham F. 
Published: December 2006

AbstractThis work presents the results of solvation of electrons on several hypothetical cyclooctane and cyclohexane molecular surfaces, using the hydrogen fluoride (HF) dimer. These complexes were constructed with extensive OH groups on one side of a hydrocarbon surface (i.e., cyclohexane sheets), which creates hydrogen‐bonded networks that can form, increasing the dipole moment of the system. Concurrently, the hydrogen atoms on the opposite side of the surface form a pocket of positive charge that can attract excess electrons. Two possible orientations for HF dimer solvation on eight molecular surfaces that have been demonstrated to be stable toward electron detachment are examined. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Variation in digestive efficiency of captive North American river otters (Lontra canadensis) on various diets
Authors: White Steffany C. , Clark David W. , Day Carrie D. , Sikes Robert S. 
Published: December 2006

AbstractEnergy content, proximate nutrient values, passage rate, and digestive efficiency associated with various diet types and factors affecting these parameters have not been quantified for the North American river otter (Lontra canadensis). We measured energy digestive efficiency (DEff) and intestinal passage rate of three captive river otters on their regular diet (a combination of polar bear diet, cat food, and feline diet) and on test diets consisting of the constituent components of their regular diet. Gross energy, crude protein, crude fat, and crude fiber varied appreciably among diet components. Caloric DEff values were high (cat food and polar bear diet combination: 83.11%; regular diet: 86.62%; feline diet: 90.22%) indicating diets high in fat and protein permit greater energy absorption. Passage rates ranged from 167–188 minutes and were influenced by level of activity such that passage rate was more rapid at higher levels of activity. Coefficients of variation (CV) from DEff (CV=1.51) and digesta passage rates (CV=7.35) were dissimilar, indicating that a direct measure may yield a more precise estimate of absorption over digesta passage rates. To further understand energy handling by river otters on diets used in zoologic institutions and to better provide the nutrient dense diets this active species requires, additional studies quantifying energetic parameters for captive otters of various genders, ages, and reproductive conditions on other diet types are needed. Zoo Biol 0: 1–10, 2007. © 2006 Wiley‐Liss, Inc.
Assessments of Anal Canal Sensitivity in Patients with Soiling 5 Years or More after Colectomy, Mucosal Proctectomy, and Ileal J Pouch‐Anal Anastomosis for Ulcerative Colitis
Authors: Tomita Ryouichi , Igarashi Seigo 
Published: December 2006

AbstractIntroductionTo clarify the significance of anal canal sensitivity contribution to soiling in patients after ileal J pouch‐anal anastomosis (IPAA) for ulcerative colitis (UC), we studied the sensory function of the anal canal.MethodsForty patients with UC who had undergone IPAA with ileostomy closure at least 60 to 132 months (mean 103.6 months) previously, and who had no preoperative or postoperative complications were recruited. They were divided into two groups: group A [n = 26; patients without soiling (16 males, 10 females; ages 15–49 years, mean 36.6 years)] and group B [n = 14; patients with soiling (10 men, 4 women; ages 24–56 years, mean 40.9 years)] compared with group C [n = 28; control subjects (18 men, 10 women; aged 19–49 years, mean 38.5 years)]. Patients with soiling were also divided into three groups (B1, rare soiling; B2, occasional soiling; B3, frequent soiling). The anal canal sensitivity threshold was measured using an anal canal electrosensitivity test (ACEST). The measurement point of anal canal was divided into three parts: lower part [1 cm below the dentate line (DL), middle part (just on the DL), and upper part (1 cm above the DL]. A small electric current from a constant‐current generator was passed between the electrodes until the patient felt a sensation often described as tingling or pulsing. The threshold of sensitivity was assessed in the upper, middle, and lower parts of the anal canal.ResultsIn patients of group C, recording at the middle part of the anal canal showed the best results. The anal canal sensitivity threshold of group B was significantly higher than those of groups A and C at the upper and middle parts (P < 0.0001, respectively). There were no significant differences at the lower part among groups. The anal canal sensitivity threshold of subgroup B3 was significantly higher than those of groups B1 or B2 at both the upper part (P = 0.0002, P = 0.0038, respectively) and middle part (P = 0.0001, P = 0.0480, respectively). There were no significant differences at the lower part among groups.ConclusionsThe ACEST shows significantly lower sensitivity in the proximal and middle anal canal in IPAA patients with soiling.
Posterior Retroperitoneoscopic Adrenalectomy: A Comparison between the Initial Experience in the Invention Phase and Introductory Phase of the New Surgical Technique
Authors: Barczyński Marcin , Konturek Aleksander , Gołkowski Filip , Cichoń Stanisław , Huszno Bohdan , Peitgen Klaus , Walz Martin K. 
Published: December 2006

AbstractBackgroundToday, the posterior retroperitoneoscopic technique has become a standard procedure in adrenal surgery. The procedure allows direct access to the adrenal glands, but it seems to be difficult because of the uncommon anatomic view. This study compares the learning period of the new procedure of “posterior retroperitoneoscopic adrenalectomy” in the primary invention phase and the secondary introductory phase in a different hospital 10 years later.Materials and MethodsThe analysis included 100 posterior retroperitoneoscopic adrenalectomies (PRA) and involved 50 procedures in each center. Group A consisted of 44 patients (14 males, 30 females; age: 48.7 ± 14.5 years) undergoing surgery between 07/1994 and 8/1996 (24 right, 26 left; 8 Cushing adenomas, 14 Conn adenomas, 11 pheochromocytomas, 7 nonfunctioning adrenocortical adenomas, 10 ACTH‐dependent adrenal hyperplasias). Group B consisted of 50 patients (12 males, 38 females; mean age 59.3 ± 10.7 years) operated between 01/2004 and 01/2006 (28 right, 22 left tumors; 5 Cushing adenomas, 12 Conn adenomas, 4 pheochromocytomas, 29 nonfunctioning adrenocortical adenomas). All PRAs were performed with the patient in the prone position with 3–4 trocars placed caudally in the region of the 11th and 12th ribs. In group A, the surgical team developed the technique of PRA themselves. Before their first PRA, the surgical team of group B was introduced to the technique by the group A surgeons and afterwards were supervised continuously.ResultsNo serious intraoperative or postoperative complication occurred in either group. Group A experienced 7 conversions to open surgery, whereas group B had one conversion and one early reoperation due to bleeding (P = 0.03; χ2‐test). The mean operative time was 117 ± 41 minutes versus 83 ± 35 minutes (group A and B respectively; P < 0.001; t‐test). Estimated blood loss was similar in the two groups (47.2 ± 46.2 ml versus 54 ± 16.3 ml, group A versus B, respectively; P = 0.36; t‐test).ConclusionsThe study demonstrates the feasibility, safety, and reproducibility of the new surgical method of PRA both when it is employed in the early phase of invention, as well as when performed by surgeon‐learners. After comprehensive training, the operative time and conversion rate are dramatically reduced, allowing for a short learning period.
Surface properties of linear alkyl benzene sulfonates in hard river water
Authors: Zhu Yun‐Peng , Rosen Milton J. , Morrall Stephen W. , Tolls Johannes 
Published: December 2006

AbstractSurface properties of a series of highly purified linear alkyl benzene sulfonates were extensively studied in hard river water. The effects of water hardness, alkyl chain length and position of the phenyl sulfonate group in the molecule on such surface properties as pC20, critical micelle concentration (CMC), γCMC, CMC/C20 ratio, and minimum area per molecule at the interface are discussed in detail. The position of phenyl sulfonate group in the molecule was found to have a pronounced effect on the CMC, γCMC value, CMC/C20 ratio, and, to the contrary, a relatively small effect on the pC20 value. The linear relationship between pC20 or‐log CMC, and m, the number of carbon atoms in the alkyl chain, was found for surfactants with the phenyl sulfonate group either at the terminal position or at the more central position in the molecule. γCMC decreases but the CMC value increases, when the position of phenyl sulfonate group moves from the terminal toward a more central position of the molecule, reflecting the “Hartley Effect” resulting from the branched alkyl chain.
Structure and function of animal fatty acid synthase
Authors: Chirala Subrahmanyam S. , Wakil Salih J. 
Published: December 2006

AbstractFatty acid synthase (FAS; EC 2.3.1.85) of animal tissues is a complex multifunctional enzyme consisting of two identical monomers. The FAS monomer (∼270 kDa) contains six catalytic activities and from the N‐terminus the order is β‐ketoacyl synthase (KS), acetyl/malonyl transacylase (AT/MT), β‐hydroxyacyl dehydratase (DH), enoyl reductase (ER), β‐ketoacyl reductase (KR), acyl carrier protein (ACP), and thioesterase (TE). Although the FAS monomer contains all the activities needed for palmitate synthesis, only the dimer form of the synthase is functional. Both the biochemical analyses and the small‐angle neutron‐scattering analysis determined that in the dimer form of the enzyme the monomers are arranged in a head‐to‐tail manner generating two centers for palmitate synthesis. Further, these analyses also suggested that the component activities of the monomer are organized in three domains. Domain I contains KS, AT/MT, and DH, domain II contains ER, KR, and ACP, and domain III contains TE. Approximately one fourth of the monomer protein located between domains I and II contains no catalytic activities and is called the interdomain/core region. This region plays an important role in the dimer formation. Electron cryomicrographic analyses of FAS revealed a quaternary structure at approximately 19 Å resolution, containing two monomers (180×130×75 Å) that are separated by about 19 Å, and arranged in an antiparallel fashion, which is consistent with biochemical and neutron‐scattering data. The monomers are connected at the middle by a hinge generating two clefts that may be the two active centers of fatty acid synthesis. Normal mode analysis predicted that the intersubunit hinge region and the intrasubunit hinge located between domains II and III are highly flexible. Analysis of FAS particle images by using a simultaneous multiple model single particle refinement method confirmed that FAS structure exists in various conformational states. Attempts to get higher resolution of the structure are under way.
Transient confinement zones: A type of lipid raft?
Authors: Chen Yun , Yang Bing , Jacobson Ken 
Published: December 2006

AbstractMany important signaling events are initiated at the cell membrane. To facilitate efficient signal transduction upon stimulation, membrane microdomains, also known as lipid rafts, are postulated to serve as platforms to recruit components involved in the signaling complex, but few methods exist to study rafts in vivo. Single particle tracking provides an approach to study the plasma membrane of living cells on the nano‐scale. The trajectories of single gold particles bound to membrane proteins and lipids are characterized in terms of both random and confined diffusion; the latter occurs in “transient confinement zones”. Here we review transient confinement zones and some of their implications for membrane structure and function.
Conjugated linoleic acids (CLA) as precursors of a distinct family of PUFA
Authors: Banni Sebastiano , Petroni Anna , Blasevich Milena , Carta Gianfranca , Cordeddu Lina , Murru Elisabetta , Melis Maria Paola , Mahon Anne , Belury Martha A. 
Published: December 2006

AbstractOne of the possibilities for distinct actions of c9,t11‐ and the t10,c12‐conjugated linoleic acid (CLA) isomers may be at the level of metabolism since the conjugated diene structure gives to CLA isomers and their metabolites a distinct pattern of incorporation into the lipid fraction and metabolism. In fact, CLA appears to undergo similar transformations as linoleic acid but with subtle isomer differences, which may account for their activity in lowering linoleic acid metabolites in those tissues rich in neutral lipids where CLA is preferentially incorporated. Furthermore, c9,t11 and t10,c12 isomers are metabolized at a different rate in the peroxisomes, where the shortened metabolite from t10,c12 is formed at a much higher proportion than the metabolite from c9,t11. This may account for the lower accumulation of t10,c12 isomer into cell lipids. CLA isomers may therefore be viewed as a “new” family of polyunsaturated fatty acids (PUFA) producing a distinct range of metabolites using the same enzymatic system as the other (i.e., n−3, n−6 and n−9) PUFA families. It is likely that perturbation of PUFA metabolism by CLA will have an impact on eicosanoid formation and metabolism, closely linked to the biological activities attributed to CLA.
Does Small Intestinal Atresia Affect Epithelial Protein Expression in Human Newborns?
Authors: Schaart Maaike W , Yamanouchi Takeshi , van Nispen Danielle JPM , Raatgeep Rolien HC , van Goudoever Johannes B , de Krijger Ronald R , Tibboel Dick , Einerhand Alexandra WC , Renes Ingrid B 
Published: December 2006

ABSTRACTObjectives:Bowel segments distal to a congenital intestinal obstruction have been suggested to be immature. In other words, luminal components such as amniotic fluid (before birth) and/or enteral nutrition (after birth) may be required to activate intestinal epithelial protein expression, thereby influencing epithelial differentiation. We investigated cell‐type–specific protein expression proximal and distal to jejunal and ileal atresias in human newborns.Patients and Methods:We immunohistochemically studied intestinal tissue specimens of 16 newborns who had undergone surgery for jejunal or ileal atresia. Sections were taken from both the proximal and distal sides of the atresias.Results:For all patients, the enterocyte‐specific markers lactase, sucrase‐isomaltase, sodium glucose cotransporter 1, glucose transporters 2 and 5, intestinal fatty acid–binding protein and alkaline phosphatase were expressed at a mean 3 ± 1 days after birth, both proximal and distal to jejunal and ileal atresias. Expression of goblet cell–specific markers mucin 2 and trefoil factor 3 and that of the Paneth cell marker lysozyme was maintained at either side of the atretic segment.Conclusions:With respect to the markers used, the human small intestinal epithelium is already differentiated shortly after birth. The absence of intestinal continuity in case of a jejunal or ileal atresia does not affect epithelial protein expression. This would seem to indicate that the developing small intestinal epithelium matures independently of luminal components.
Human Faecal Microbiota Develops the Ability to Degrade Type 3 Resistant Starch During Weaning
Authors: Scheiwiller Judith , Arrigoni Eva , Brouns Fred , Amadò Renato 
Published: December 2006

ABSTRACTBackground:Colonisation of the human colon starts immediately after birth. Bacterial composition is substantially influenced by the type of feeding. During weaning, microbiota diversifies considerably to finally approach the composition of that of adults. The aim of this study was to investigate the ability of colonic microbiota obtained from different age groups to ferment resistant starch (RS).Methods:Faecal samples of breast‐fed and formula‐fed infants, infants at weaning, adults and elderly subjects were used as inocula. Fermentation experiments were performed by applying a standardised in vitro batch method. Fermentability was established by measuring both metabolite production and substrate degradation. An RS type 3 (RS‐3) was used as substrate; its behaviour was compared with that of lactulose (positive control), whereas inoculum without substrate was used as negative control.Results:Overall fermentation patterns clearly showed that the human microbiota of all age groups is able to degrade lactulose. In contrast, RS‐3 was found resistant to the attack by microbiota of both breast‐fed and formula‐fed infants. Bacteria collected from infants at weaning were able to degrade RS‐3 completely, but slower compared with adults. With increasing age, RS‐3 fermentation was observed to be slightly retarded again.Conclusions:Human faecal microbiota of all age groups is able to ferment lactulose in vitro quickly and completely. The ability to degrade RS‐3, however, is only established during weaning. Whether fermentation‐related production of short‐chain fatty acids from RS‐3 and concurrent modifications of the microbiota can result in potential health benefits to the host at this stage of life needs to be elucidated.