bluuebunny/crossref_metadata_2025 huggingface dataset:
Glucose production and substrate cycle activity in a fasting adapted animal, the northern elephant seal
Authors: Champagne Cory D. , Houser Dorian S. , Crocker Daniel E.
Published: March 2005

During prolonged fasting physiological mechanisms defend lean tissue from catabolism. In the fasting state, glucose is derived solely from gluconeogenesis, requiring some catabolism of amino acids for gluconeogenic substrates. This creates a conflict in animals undergoing fasts concurrently with metabolically challenging activities. This study investigated glucose metabolism in fasting and developing neonatal elephant seals. Glucose production and glucose cycle activity were measured early (2 weeks) and late(6 weeks) in the postweaning fasting period. Additionally the role of regulatory hormones on glucose production and glucose cycle activity were investigated. Glucose cycle activity was highly variable throughout the study period, did not change over the fasting period, and was not correlated with insulin or glucagon level. Endogenous glucose production (EGP) was 2.80±0.65 mg kg–1 min–1 early and 2.21±0.12 during late fasting. Insulin to glucagon molar ratio decreased while cortisol levels increased over the fast (t=5.27,2.84; P=0.003, 0.04; respectively). There was no relationship between EGP and hormone levels. The glucose production values measured in this study were high and exceeded the estimated gluconeogenic substrate available. These data suggest extensive glucose recycling via Cori cycle activity occurring in northern elephant seals, and we propose a possible justification for this recycling.
Contextual effects of small environments on the electric images of objects and their brain evoked responses in weakly electric fish
Authors: Pereira Ana Carolina , Centurión Viviana , Caputi Angel Ariel
Published: March 2005

This article reports some contextual effects of fish hovering in small environments on active imaging. Foveal electrosensory images of objects and their corresponding evoked responses in the electrosensory lobe are altered in amplitude and waveform when the fish are inside tubes. The article describes:(i) the physical basis of the changes imposed by small environments on electric images, (ii) the field potential responses at the electrosensory lobe of chronically implanted animals when entering and leaving tubes, and (iii)the effect of context on object discrimination. Biophysical analysis indicates that tubes cause a change in the efficiency of a previously described pre-receptor/post-effector mechanism responsible for the electric`illumination' of nearby objects (as mirrors change the illumination of visual scenes). Field potential responses at the electrosensory lobe showed two components corresponding to the fast- and slow-electrosensory pathways respectively: (a) an early spike following the input without adaptation; (b) a series of waves lasting the rest of the cycle and exhibiting different degrees of adaptation. Discrimination experiments showed that fish react to changes in image rather than to changes in object resistance. The amplitude of the novelty responses evoked by similar changes in the total energy of electric images was constant despite the large change in basal stimulus amplitude and waveform caused by hovering in the tubes. These facts may be explained by the presence of adaptive responses observed at the slow pathway in the electrosensory lobe.
UV incites diverse levels of DNA breaks in different cellular compartments of a branching coral species
Authors: Baruch Rinkevich , Avishai Nanthawan , Rabinowitz Claudette
Published: March 2005

This study evaluates in vitro the effects of UVB irradiation on three cellular compartments of a shallow water coral species. Coral tissues were dissociated by Ca2+-Mg2+-free artificial seawater. Cell suspensions were divided into the major cellular compartments (animal cells, algal cells, holobiont entities) by sucrose gradient and then by detergent treatments. Cell fractions were irradiated by UVB lamp (4.05, 8.1 and 12.2 kJ m–2) and subjected to the comet assay. UVB radiation, at levels that induced a moderate DNA breakage to the non-symbiotic coral and algal cell compartments, caused dramatic increase in DNA breakage to the holobiont entities. After a 1 h repair period, DNA breakage levels in the algal and animal cell fractions were augmented as compared with a reduction in DNA breakage in the holobiont fraction. This discordancy in DNA breakage between the three cellular compartments reveals that the holobiont cell fraction is more vulnerable to increased natural UV irradiation and associated anthropogenic genotoxic impacts, providing another possible explanation for recent increase in worldwide coral bleaching events.
Effects of levothyroxine treatment on biochemical and hemostasis parameters in patients with hypothyroidism
Authors: Gullu Sevim , Sav Hasan , Kamel Nuri
Published: March 2005

Objective: The aims of the study were to evaluate the disturbances in the coagulation system in patients with overt hypothyroidism (OH), to assess the effects of levothyroxine (LT4) on the coagulation parameters, and to determine whether subclinical hypothyroidism (SH) affects concentrations of coagulation markers and several biochemical parameters, thereby supporting early substitution.

Design: The study included 15 patients with SH (TSH levels 5–10 mU/l), 15 patients with OH and 15 euthyroid controls.

Methods: Blood urea nitrogen, creatinine, creatine phosphokinase, aspartate aminotransferase, lactate dehydrogenase, total-cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol and triglyceride levels, and bleeding time, prothrombin time (PT), activated partial thromboplastin time (APTT), factor VIII activity, von Willebrand factor activity (vWF), platelet count and clotting time were evaluated just before and three months after the maintenance of euthyroidism with LT4 treatment.

Results: Factor VIII and vWF activities were lower in patients with SH than in controls (P< 0.01). Increased bleeding time, PT, APTT and clotting time and decreased factor VIII activity and vWF activity were observed in patients with OH when compared with controls. Bleeding time, PT, APTT and clotting time decreased and factor VIII activity, vWF and platelet count increased after LT4 in patients with OH. Increases in factor VIII activity and vWF (P< 0.01) were detected also in the SH group with treatment.

Conclusions: OH is associated with significant abnormalities in clotting parameters which are reversed by LT4. In contrast, SH is associated with minor changes in factor VIII activity and vWF which are reversible by LT4. Serum lipids and other measured parameters are not improved by LT4 in patients with TSH < 10 mU/l and these data fail to demonstrate a need to treat such patients.
Androgen receptor gene CAG and GGC repeat lengths in cryptorchidism
Authors: Ferlin Alberto , Garolla Andrea , Bettella Andrea , Bartoloni Lucia , Vinanzi Cinzia , Roverato Alberto , Foresta Carlo
Published: March 2005

Objective: Cryptorchidism is the most common congenital birth defect in male children, and accumulating evidence suggests that genetic abnormalities may be associated with it. The androgen receptor has two polymorphic sites in exon 1, with different numbers of CAG and GGC repeats, resulting in variable lengths of polyglutamine and polyglycine stretches. Longer CAG repeats result in a reduced androgen receptor transcriptional activity, but the role of the GGC triplets is less clear. In this study we analysed CAG and GGC repeat lengths in men with a history of cryptorchidism, associated or not with impairment of sperm production, in comparison with normal fertile subjects.

Methods: We analysed CAG and GGC repeat lengths in a group of 105 ex-cryptorchid men in comparison with 115 fertile non-cryptorchid men.

Results: No difference was found between patients and controls in the mean and median values, and in distribution of CAG and GGC, when considered separately. However, the analysis of the joint distribution of CAG and GGC showed that some combinations are significantly more frequent in men with bilateral cryptorchidism (who frequently presented severe testiculopathies), in a manner similar to that found in idiopathic infertile subjects.

Conclusions: Although further studies are needed to elucidate the possible role of specific CAG/GGC combinations as a causative factor, these data suggest a possible association between androgen receptor gene polymorphisms and cryptorchidism.
Evidence for altered adipocyte function in polycystic ovary syndrome
Authors: Carmina E , Orio F , Palomba S , Cascella T , Longo R A , Colao A M , Lombardi G , Lobo R A
Published: March 2005

Background: Adipocytokines are produced by adipose tissue and have been thought to be related to insulin resistance and other health consequences. We measured leptin, adiponectin, and resistin simultaneously in women with polycystic ovary syndrome (PCOS) and age- and weight-matched controls. Our hypothesis was that these simultaneous measurements would help determine whether adipocytokine secretion is abnormal in PCOS independent of body mass and whether these levels are related to insulin resistance as well as other hormonal changes.

Methods: Fifty-two women with PCOS and 45 normal ovulatory women who were age- and weight-matched were studied. Blood was obtained for adipocytokines (leptin, adiponectin, and resistin) as well as hormonal parameters and markers of insulin resistance as assessed by the quantitative insulin-sensitivity check index. Body mass index (BMI) was stratified into obese, overweight, and normal subgroups for comparisons between PCOS and controls.

Results: Adiponectin was lower (P < 0.05) and resistin was higher (P < 0.05) while leptin was similar to matched controls. Breakdown of the groups into subgroups showed a strong body mass relationship for leptin with no changes in resistin although adiponectin was lower in PCOS, even controlling for BMI. In controls, leptin and adiponectin and leptin and resistin correlated (P < 0.05) but not in PCOS. In controls, all adipocytokines correlated with markers of insulin resistance but not in PCOS.

Conclusions: When matched for BMI status, decreased adiponectin in PCOS represent the most marked change. This alteration may be the result of altered adipose tissue distribution and function in PCOS but no correlation with insulin resistance was found.
Serum markers of GH and insulin action in 12-year-old children born small for gestational age
Authors: Tenhola Sirpa , Halonen Pirjo , Jääskeläinen Jarmo , Voutilainen Raimo
Published: March 2005

Objectives: Our aim was to determine whether markers of growth hormone and insulin action differ between children born small for gestational age (SGA) and those born of an appropriate size for gestational age (AGA).

Design: Fifty-five SGA children and their 55 age- and sex-matched AGA control subjects were studied in a case-control setting at 12 years of age.

Methods: We examined serum concentrations of insulin-like growth factor (IGF)-I, IGF-II, IGF-binding protein (IGFBP)-1 and IGFBP-3, sex hormone binding globulin (SHBG), leptin, fasting insulin, and blood glucose. Insulin sensitivity was evaluated by the homeostasis model assessment for insulin resistance (HOMA-IR).

Results: The body mass index (BMI), sex, and puberty-adjusted mean serum IGF-I concentration was higher in the SGA than in the AGA children (303.4 vs 282.3 μg/l, P = 0.006). The mean serum concentrations of IGF-II, IGFBP-I, IGFBP-3, SHBG, fasting insulin, blood glucose and HOMA-IR did not differ between the SGA and the AGA group. The BMI, sex, and puberty-adjusted mean serum leptin concentration was lower in the SGA than in the AGA children (7.9 vs 10.1 μg/l, P = 0.037). In multiple logistic regression analysis, high HOMA-IR predicted high serum IGF-I levels in the SGA children (odds ratio 8.3; 95% confidence interval 1.7–41; P = 0.010), whereas in the AGA group HOMA-IR did not associate with the serum IGF-I level.

Conclusions: The BMI, sex, and puberty-adjusted mean serum IGF-I concentration was significantly higher and the leptin concentration was lower in the SGA than in the AGA children. No differences were found in the indices of insulin action or sensitivity between the SGA and AGA children at 12 years of age. However, HOMA-IR strongly associated with serum IGF-I levels in the SGA children.
GH/IGF-I and bone resorption in vivo and in vitro
Authors: Ueland Thor
Published: March 2005

IGF-I may act as one of several coupling agents by activating bone formation and bone resorption.In vivostudies in normal subjects, postmenopausal women and patients with excess or diminished GH production (acromegaly and GHD) indicate that both GH and IGF-I activate osteoclasts, but that GH has a more pronounced effect, independently of IGF-I.In vitro, GH and IGF receptors have been demonstrated on osteoclasts and both GH and IGF-I may directly modify osteoclast function and activity. In addition to direct effects on osteoclasts, GH and IGF-I may affect bone resorption indirectly by stimulating release of paracrine mediators that regulate osteoclastic resorption (cytokines). Critical for the bone resorptive process is the balance between OPG and RANKL, which is regulated by many systemic factors.In vivoandin vitro,GH/IGF-I may modulate this balance but these studies are difficult to interpret, reflecting the complexity of this system. Increased OPG expression may possibly protect against GH/IGF-I-induced bone resorption and potentially be important for the long-term beneficial effects of GH replacement. Further studies investigating the OPG/RANKL ratio and system in experimental and transgenic GH/IGF models may clarify these issues.
Improvements Offered by Coprecipitation of Sintering Additives on Ultra‐Fine SiC Materials
Authors: Sciti D. , Balbo A. , Bellosi A.
Published: March 2005

A commercial SiC powder is processed through either conventional ultrasonication or coprecipitation of sintering additives, to obtain dense materials. The coprecipitation process involves a change of the surface properties of SiC particles which concerns the formation of amorphous precipitates (see the figure) deriving from the sintering aids and partial dissolution of the surface silica. These factors lead to microstructural refinement and reduction of the intergranular phase amount in dense samples.
Ordered‐subset analysis of savant skills in autism for 15q11‐q13
Authors: Ma D.Q. , Jaworski J. , Menold M.M. , Donnelly S. , Abramson R.K. , Wright H.H. , Delong G.R. , Gilbert J.R. , Pericak‐Vance M.A. , Cuccaro Michael L.
Published: March 2005

Autism is a complex disorder characterized by genetic and phenotypic heterogeneity. Analysis of phenotypically homogeneous subtypes has been used to both confirm and narrow potential autism linkage regions such as the chromosomal region 15q11‐q13. Increased evidence for linkage in this region had been found in a subgroup of 21 autism families (total families = 94) stratified based on a savant skill factor (SSF) from the Autism Diagnostic Interview, Revised (ADI‐R). We examined the savant phenotypic finding in our sample of 91 multiplex autism families. Using two‐point parametric analysis in stratification with a cutoff point of a savant skill score of 0.16, our families failed to demonstrate linkage to 15q11‐q13. In addition, ordered subset analysis (OSA) using SSF as a covariate also failed to show evidence for linkage. Our findings do not support savant skills as an informative phenotypic subset for linkage in our sample. © 2005 Wiley‐Liss, Inc.
Synthesis, in vitro‐Antimycobacterial Activity and Cytotoxicity of Some Alkyl α‐(5‐aryl‐1, 3, 4‐thiadiazole‐2‐ylthio)acetates
Authors: Foroumadi Alireza , Soltani Fatemeh , Moallemzadeh‐Haghighi Hamideh , Shafiee Abbas
Published: March 2005

A new series of alkyl α‐[5‐(5‐nitro‐2‐furyl)‐1, 3, 4‐ thiadiazole‐2‐ylthio] and α‐[5‐(1‐methyl‐5‐nitro‐2‐imidazolyl)‐1, 3, 4‐thiadiazole‐2‐ylthio]acetates (6a–e, 6f–j) were synthesized and evaluated against Mycobacterium tuberculosis as part of the TAACF (Tuberculosis Antimicrobial Acquisition and Coordinating Facility) TB screening program. Primary screening was conducted at the single concentration of 6.25 μg/mL against M. tuberculosis H37Rv in BACTEC 12B medium using a broth microdilution assay, the Microplate Alamar Blue Assay (MABA). The minimum inhibitory concentration (MIC) was determined for compounds demonstrating >90 % growth inhibition in the primary screening. Seven compounds were efficient antimycobacterial agents showing MIC values ranging from 0.78 to 6.25 μg/mL. Among nitrofuran derivatives, methyl (6a), ethyl (6b), and benzyl (6e) esters displayed a good antituberculosis activity (MIC=0.78–3.13 μg/mL) and the others were inactive. In the nitro imidazole series, methyl (6f), ethyl (6g), propyl (6h) and butyl (6i) esters showed significant activity against M. tuberculosis while benzyl (6j) ester was inactive. Also, active compounds were screened by serial dilution to assess toxicity to a VERO cell line. A varying degree of toxicity was observed in nitrofuran and nitroimidazole derivatives (IC50 = 2.3 – >10 μg/mL).
Transition Metal Catalyzed Decarboxylative Additions of Enolates
Authors: Tunge Jon A. , Burger Erin C.
Published: March 2005

Transition metal catalyzed decarboxylation of β‐keto acids and esters provides a convenient route for the regiospecific generation of enolates under neutral conditions. Enolates generated by decarboxylation have been utilized in aldol and Michael additions as well as allylic alkylations. The scope and mechanisms of these transformations are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Bystander signaling between glioma cells and fibroblasts targeted with counted particles
Authors: Shao Chunlin , Folkard Melvyn , Michael Barry D. , Prise Kevin M.
Published: March 2005

Radiation‐induced bystander effects may play an important role in cancer risks associated with environmental, occupational and medical exposures and they may also present a therapeutic opportunity to modulate the efficacy of radiotherapy. However, the mechanisms underpinning these responses between tumor and normal cells are poorly understood. Using a microbeam, we investigated interactions between T98G malignant glioma cells and AG01522 normal fibroblasts by targeting cells through their nuclei in one population, then detecting cellular responses in the other co‐cultured non‐irradiated population. It was found that when a fraction of cells was individually irradiated with exactly 1 or 5 helium particles (3He2+), the yield of micronuclei (MN) in the non‐irradiated population was significantly increased. This increase was not related to the fraction of cells targeted or the number of particles delivered to those cells. Even when one cell was targeted with a single 3He2+, the induction of MN in the bystander non‐irradiated population could be increased by 79% for AG01522 and 28% for T98G. Furthermore, studies showed that nitric oxide (NO) and reactive oxygen species (ROS) were involved in these bystander responses. Following nuclear irradiation in only 1% of cells, the NO level in the T98G population was increased by 31% and the ROS level in the AG0 population was increased by 18%. Treatment of cultures with 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethyl‐imidazoline‐1‐oxyl‐3‐oxide (c‐PTIO), an NO scavenger, abolished the bystander MN induction in non‐irradiated AG01522 cells but only partially in non‐irradiated T98G cells, and this could be eliminated by treatment with either DMSO or antioxidants. Our findings indicate that differential mechanisms involving NO and ROS signaling factors play a role in bystander responses generated from targeted T98G glioma and AG0 fibroblasts, respectively. These bystander interactions suggest that a mechanistic control of the bystander effect could be of benefit to radiotherapy. © 2005 Wiley‐Liss, Inc.
Biostability of polyether–urethane scaffolds: A comparison of two novel processing methods and the effect of higher gamma‐irradiation dose
Authors: Haugen H. , Gerhardt L. C. , Will J. , Wintermantel E.
Published: March 2005

This article deals with enzyme‐induced biodegradation behavior of thermoplastic polyether–urethane (TPU). Porous scaffolds were processed by a new foaming method applied in hot pressing and injection molding. The scaffolds were subsequently γ sterilized. The samples were incubated with cholesterol esterase (CE) for 28 days to simulate an enzymatic degradation order to assess polymer biostability. The main focus of degradation products was the most toxic one: methylene dianiline (MDA). LC/MS was used to separate the breakdown products and to identify possible MDA amounts. The results showed that (a) the hot‐pressed sample released an MDA amount almost twice as large (0.26 ng ± 0.008) as that of the injection‐molded samples (0.15 ng ± 0.003) after incubation with enzyme activity in the physiological range, and (b) a tenfold increase in CE activity revealed considerably higher MDA amounts (7540.0 ng ± 0.004). This enzyme concentration is physiologically unlikely, however, but may occur for extreme high inflammation behavior. Even for extremely high levels of CE enzyme, the scaffold will not discharge MDA above toxic levels. The injection‐molded samples sterilized at 25 kGy seem to represent the most promising processing method. Therefore, the new injection‐molding foaming process of polyether–urethane can be considered appropriate for use as a biomaterial. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Doppler sonography of the normal lacrimal gland
Authors: Bilgili Yasemin , Taner Pelin , Unal Birsen , Simsir Ilknur , Kara Simay Altan , Bayram Merih , Alicioglu Banu
Published: March 2005

Purpose

We used Doppler sonography to determine the resistance index (RI) and pulsatility index (PI) of the normal lacrimal artery (LA) in both females and males. We also compared the values obtained at various periods of reproductive life.

Methods

The study was performed in 25 prepubertal girls, 28 females of reproductive age, and 27 postmenopausal women, 23 pregnant women, and 104 healthy males. Doppler sonography was used to determine the RI and PI of the LA.

Results

The mean PI for the entire patient population was 1.48 ± 0.60 and the RI was 0.72 ± 0.09. The RI and PI values of the LA did not differ between males and females. Similarly, the mean RI and PI values of the LA did not change significantly between the various reproductive phases.

Conclusion

The PI and RI of the lacrimal gland are similar in both sexes. Moreover, they are not altered by changes in levels of sex steroids. © 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:123–126, 2005
Sonographic features of Ebstein anomaly associated with hydrops fetalis: A report of two cases
Authors: Tongsong Theera , Chanprapaph Pharuhas , Khunamornpong Surapan , Sirichotiyakul Supatra
Published: March 2005

Ebstein anomaly, an abnormally low insertion of the tricuspid valve, occurs in 0.5% of patients with congenital heart disease. In rare cases, this disorder may be complicated by congestive heart failure in utero and hydrops fetalis. This article reports the prenatal sonographic features of 2 cases of Ebstein anomaly associated with hydrops fetalis. In both cases, fetal echocardiography was performed at 34 weeks of gestation. The 4‐chamber view showed fetal cardiomegaly and pericardial effusion. In both cases, the annular attachment of the tricuspid valve leaflets was difficult to demonstrate and so distal that it could easily be confused with papillary muscle in the right ventricular wall. Poor fetal cardiac hemodynamics with severe tricuspid regurgitation was demonstrated by pulsed Doppler imaging. Pulmonary regurgitation was also clearly demonstrated in both cases. Preterm delivery with stillbirth occurred in both cases. Autopsies confirmed the very distal displacement of the tricuspid valve insertion, close to the apex, and enlargement of the right atrium. © 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:149–153, 2005
Transcriptional regulation of connexin 43 expression by retinoids and carotenoids: Similarities and differences
Authors: Vine Alex L. , Leung Yee M. , Bertram John S.
Published: March 2005

Gap junctions, connexons, are formed by assembly of trans‐membrane connexin proteins and have multiple functions including the coordination of cell responses. Most human tumors are deficient in gap junctional communication (GJC) and restoration of GJC by forced expression of connexins reduces indices of neoplasia. Expression of connexin 43 (Cx43), the most widely‐expressed connexin family member, is upregulated by cancer‐preventive retinoids and carotenoids in normal and preneoplastic cells; an action considered of mechanistic significance. However, the molecular mechanism for upregulated expression is poorly understood. The retinoic acid receptor antagonist Ro 41‐5253 was capable of suppressing retinoid‐induction Cx43 luciferase reporter construct in F9 cells, but did not suppress reporter activity induced by the non‐pro‐vitamin A carotenoids astaxanthin or lycopene, indicating that retinoids have separate mechanisms of gene activation than non‐pro‐vitamin A carotenoids. Neither class of compound required protein synthesis for induction ofCx43mRNA, nor was the 5.0 h half‐life ofCx43mRNA altered, indicating direct transcriptional activation. The responsive region was found within −158 bp and +209 bp of the transcription start site; this contains a Sp1/Sp3 GC‐box to which Sp1 and Sp3 were bound, as revealed by electrophoretic mobility shift assays (EMSA), but no retinoic acid response element (RARE). Site directed mutagenesis of this GC‐box resulted in increased basal levels of transcription and loss of responsiveness to a synthetic retinoid. In this construct astaxanthin and lycopene produced marginally, but not significantly higher, reporter activity than the control. © 2005 Wiley‐Liss, Inc.
Characterization of the nuclear import of human MutLα
Authors: Brieger A. , Plotz G. , Raedle J. , Weber N. , Baum W. , Caspary W.F. , Zeuzem S. , Trojan J.
Published: March 2005

DNA mismatch repair (MMR) is essential for the maintenance of replication fidelity. Its major task is to recognize mismatches as well as insertion/deletion loops of newly synthesized DNA strands. Although different players of human MMR have been identified, the regulation of essential steps of MMR is poorly understood. Because MMR is initiated in the nucleus, nuclear import might be a mechanism to regulate MMR. Nuclear targeting is accomplished by conserved signal sequences called nuclear localization signals (NLS), which represent clusters of positively charged amino acids (aa). hMLH1 contains two clusters of positively charged amino acids, which are candidate NLS sequences (aa 469–472 and 496–499), while hPMS2 contains one (aa 574–580). To study the effect of these clusters on nuclear import, NLS mutants of hMLH1 and hPMS2 were generated and expressed in 293T cells. The subcellular localization of the mutant constructs was monitored by confocal laser microscopy. We demonstrated that missense mutations of two signal sequences, one in hMLH1 and one in hPMS2, lead to impaired nuclear import, which was especially prominent for mutants of the hMLH1 residues K471 and R472; and hPMS2 residues K577 and R578. © 2005 Wiley‐Liss, Inc.
The strongly connected reliability of complete digraphs
Authors: Brown J.I. , Li Xiaohu
Published: March 2005

Given a digraph D, consider the model where each vertex is always operational, but the edges are independently operational with probability p. The strongly connected reliability of D, scRel(D,p), is the probability that the spanning subgraph of D consisting of the operational edges is strongly connected. One can view strongly connected reliability as the probability that any vertex can send information to any other vertex, given that edges fail independently. There are very few classes for which there is an efficient algorithm for calculating the strongly connected reliability. This article presents the fist polynomial time algorithm for computing the strongly connected reliability of complete digraphs, that is, digraphs in which every vertex is joined to every other vertex by exactly one edge (one in each direction). © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(3), 165–168 2005
Synthesis and characterization of reactive copolymeric microgels
Authors: Pérez Leyre , Sáez Virginia , Hernáez Estíbaliz , Herrero M Teresa , Rodríguez Elena , Katime Issa
Published: March 2005

Hydrogels whose diameters range in the nanosize scale were synthesized by precipitation copolymerization of 4‐nitrophenol acrylate (NPA) with methacrylamide (MeAM) and N‐isopropylacrylamide (NIPAM). The polymerization reaction process was followed by attenuated total reflectance Fourier‐transform infrared spectrometry (ATR‐FTIR) and the conversion was studied by UV‐vis spectrometry. Poly(NPA‐co‐MeAM) and poly(NPA‐co‐NIPAM) microgels were characterized by proton nuclear magnetic resonance (1H‐NMR) spectrometry. The thermal properties were studied by both thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. Transmission electron microscopy (TEM) of these microgels showed that the copolymer is located in spherical particles with a moderate polydispersity. The average particle diameter and the particle size distribution were measured in acetone by quasi‐elastic light scattering (QELS), which indicated a mean diameter close to 50 nm. Copyright © 2005 Society of Chemical Industry
Collagen‐based scaffolds reinforced by chitosan fibres for bone tissue engineering
Authors: Li Xiaoming , Feng Qingling , Jiao Yunfeng , Cui Fuzhai
Published: March 2005

In this paper, porous bone scaffolds reinforced with chitosan fibres were prepared. The porosity and pore size of the reinforced scaffolds were both satisfactory. The reinforced scaffolds resembled natural bone in both components and crystal size. Only if the length of the fibres was no shorter than the critical length, could the fibres reinforce the material. We have proposed an empirical formula to calculate the critical length of the fibres for the porous materials and determined the modifying factor (Fl) for the porous bone scaffold investigated in this work. Along with the increase of the fibres' volume content, the compressive strength of the scaffold also increased. We have proposed a further empirical formula for calculating the compressive strength of the porous reinforced materials and determined the modifying factor (Fσ) for the porous reinforced bone scaffold examined in these studies. Along with the degradation in vitro, the decrease in strength of the reinforced scaffold was less than that of the unreinforced scaffold. The growth rate of osteoblast cells on the reinforced scaffold was higher than that on the unreinforced scaffold. These results suggest that the reinforced scaffold may be a promising candidate matrix for repairing large bone defects. Copyright © 2005 Society of Chemical Industry
Phase separation in binary mixtures containing polymers: A quantitative comparison of single‐chain‐in‐mean‐field simulations and computer simulations of the corresponding multichain systems
Authors: Müller Marcus , Smith Grant D.
Published: March 2005

We discuss a phenomenological, coarse‐grained simulation scheme, single‐chain‐in‐mean‐field (SCMF) simulation, for investigating the kinetics of phase separation in dense polymer blends and mixtures of polymers and solvents. In the spirit of self‐consistent‐field calculations, we approximate the interacting multichain problem by that of a single chain in an external field, which, in turn, depends on the local densities of the components. To study the time evolution of the mixture, we perform an explicit Monte Carlo (MC) simulation of an ensemble of independent chains in the external field and periodically calculate the average densities and update the external field. Unlike dynamic self‐consistent‐field theory, these SCMF simulations do not assume that the chain conformations relax much more quickly than the density and incorporate the single‐chain dynamics explicitly rather than via an Onsager coefficient. This allows us to study systems with large spatial inhomogeneities and dynamic asymmetries. To assess the accuracy and limitations of the simulation scheme, we compare the results of SCMF simulations using a discretized Edwards Hamiltonian with computer simulations of the corresponding multichain system for (1) the early stages of spinodal decomposition of a symmetric binary polymer blend in response to a quench from χN = 0.314 to χN = 5 (where χ is the Flory–Huggins parameter and N is the number of segments), for which the growth rate of composition fluctuations is compared with MC simulations of the bond fluctuation model and alternative dynamic self‐consistent‐field calculations, and (2) the evaporation of a solvent from a low‐molecular‐weight thin polymer film, for which a comparison is made with molecular dynamics (MD) simulations of a bead‐necklace model with a monomeric solvent. In the latter case, the polymer conformations are extracted from MD simulations and modeled in the SCMF simulations by a discretized Edwards Hamiltonian augmented by a chain‐bending potential. From the MD simulations of thin polymer films in equilibrium with its vapor, phase coexistence has been determined, and the second‐ and third‐order virial coefficients in the SCMF simulations have been adjusted accordingly. Finally, MD simulations of bulk solutions of a polymer and a solvent over a range of compositions, as well as the pure solvent at various densities, have been performed to determine self‐diffusion coefficients that enter the SCMF simulations in the form of density‐dependent segmental mobilities. A comparison of the polymer and solvent profiles in a thin film as a function of time and the fraction of the solvent evaporating from a solvent‐swollen film, as obtained from MD simulations and parameterized SCMF simulations, shows satisfactory agreement for this simple mapping procedure. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 934–958, 2005
Simulation of plastic deformation in glassy polymers: Atomistic and mesoscale approaches
Authors: Shenogin Sergei , Ozisik Rahmi
Published: March 2005

The mechanism of deformation in glasses is very different from that of crystals, even though their general behavior is very similar. In this study, we investigated the deformation of polycarbonate on the atomistic scale with molecular dynamics and on the continuum scale with a new simulation approach. The results indicated that high atomic/segmental mobility and low local density enabled the formation (nucleation) of highly deformed regions that grew to form plastic defects called plastic shear transformations. A continuum‐scale simulation was performed with the concept of plastic shear transformations as the basic region of deformation. The continuum simulations were able to predict the primary and secondary creep behavior. The slope of the secondary creep depended on the interactions between the plastic shear transformations. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 994‐1004, 2005
Biogeochemical and hydrological controls on carbon export from a forested catchment in central Japan
Authors: Kawasaki Masatoshi , Ohte Nobuhito , Katsuyama Masanori
Published: March 2005

Here we review research on the links between hydrological processes and the biogeochemical environment controlling the dynamics of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in temperate forested catchments. In addition, we present the results of original experiments. The spatial and temporal changes in DIC and DOC concentrations were investigated in tandem with observations of elementary belowground hydrological processes for a forested headwater catchment in central Japan. The soil CO2 gas concentration, which is the source of DIC, increased with depth. The hydrological characteristics of groundwater also affected the spatial variation of partial pressure of dissolved CO2 (pCO2) in groundwater. The temporal variations in the soil CO2 gas concentration and the pCO2 values of groundwater suggested that the dynamics of DIC were strongly affected by biological activity. However, the geographical differences in DIC leaching were affected not only by the link between climatological conditions and biological activity, but also by other factors such as geomorphologic conditions. The DOC concentrations decreased with selective removal of hydrophobic acid during vertical infiltration. The major DOC‐removal mechanisms were retention of metal‐organic complexes to soil solids in the upper mineral soil layer and decomposition of DOC in the lower mineral soil layer. The responses of the DIC and DOC concentrations to changes in discharge during storm events were explained by the spatial variation in the DIC and DOC concentrations. Seasonal variation, which represents a long‐term change, in stream water DOC concentrations was affected not only by the temporal variation in DOC concentrations in the topsoil, which may be affected by biological activity, but also by water movement, which transports DOC from the topsoil to stream water. These results indicate that both a biogeochemical approach and a method for evaluating the hydrological effects on carbon dynamics are critical for clarifying the carbon accumulation‐and‐release processes in forested ecosystems.
Dupuytren’s Disease Secondary to Acute Injury, Infection or Operation Distal to the Elbow in the Ipsilateral Upper Limb – A Historical Review
Authors: ELLIOT D. , RAGOOWANSI R.
Published: March 2005

The aggregated total of 385 cases of Dupuytren’s disease arising after acute or specific injury, operation or infection of the forearm, wrist or hand between 1614 and 2003 are documented, including a personal series of 52 cases. The history of this relationship is recorded and the medico legal implications of the association are discussed.
Total Wrist Fusion: A Study of 115 Patients
Authors: RAUHANIEMI J. , TIUSANEN H. , SIPOLA E.
Published: March 2005

This retrospective study evaluated the outcome of total wrist fusion, predominantly using the Mannerfelt technique, in patients with rheumatoid arthritis. One hundred and fifteen patients were operated on for painful wrist destruction. The mean pain scores were 3.6 (1–4) pre-operatively, 1.9 (1–4) after 6 weeks and 1.3 (1–4) at 1 year. Although the radiological fusion rate was good, only 40% of the patients were very satisfied with the result. Ability to perform activities of daily living was only very much improved in 30% of the patients. Grip strength significantly improved after surgery.
Manual Ability Measure (MAM-16): A Preliminary Report on a New Patient-Centred and Task-Oriented Outcome Measure of Hand Function
Authors: CHEN C. C. , GRANGER C. V. , PEIMER C. A. , MOY O. J. , WALD S.
Published: March 2005

The purpose of this study was to develop an easy-to-use and psychometrically sound outcome instrument that is task-oriented and patient-centred. One hundred fifteen patients with a variety of hand impairments completed a rating scale of perceived manual ability (i.e., the Manual Ability Measure). The first 70 patients also completed two other questionnaires about physical health and psychological well-being. Rasch Analyses were conducted to transform the ordinal ratings into linear measures; Rasch statistics were used to evaluate its measurement properties at both scale and item levels. Eighty-three original items were reduced to 16 common tasks; Rasch reliabilities were good; the easy-to-difficult item hierarchy makes sense clinically. Moderate correlations were found between manual ability, physical function and general sense of well-being. The results of this preliminary study suggest that the MAM is a promising outcome measure that has adequate psychometric properties and can be used to complement other objective clinical measurements.
Ælfric and late Old English verse
Authors: Bredehoft Thomas A.
Published: March 2005

In his discussion of the formal structures characteristic of Ælfric's ‘rhythmical prose’ style, John C. Pope prints the following passage from Ælfric's homily on Cuthbert, calling attention especially to the pointing, given as it appears in Cambridge, University Library, Gg. 3. 28 (?Cerne, s. x/xi):

Ac an ðære fugela. eft fleogende com.

ymbe ðry dagas. þearle dreorig.

fleah to his foton. friðes biddende.

þæt he on ðam lande. lybban moste.

symle unscæððig. and his gefera samod.
State Immunity in National and International Law: Three Recent Cases Before the European Court of Human Rights
Authors: Orakhelashvili Alexander
Published: March 2005

The issue of state immunity in the case of human rights violations has been controversial in the last decade, partly due to the absence of international judicial pronouncements. The bringing of the three cases previously litigated in the United Kingdom and Ireland before the European Court of Human Rights was supposed to reduce this uncertainty. However, decisions of the Court seem to have failed to meet these expectations. The Court has failed to properly examine whether the sources of international law support the scope of state immunity as portrayed in the decisions. Furthermore, the decision on Al-Adsani is deficient in that it fails to respect the difference between sovereign and non-sovereign acts, and the effects of peremptory norms with regard to state immunity.
Yeast Alcohol Dehydrogenase Bound to Membranes: Surface and Microenvironment Effects on Activity and Stability
Authors: Kennedy C. L. , Domach M. M.
Published: March 2005

The enzyme, yeast alcohol dehydrogenase, was adsorbed to porous nitrocellulose and nylon membranes. The two membranes provide different surface chemistries as indicated by the results of the streaming potential, enzyme adsorption, and fluorescein isothiocyanate adsorption experiments. The stability of the enzyme, as determined by continually measuring the extent of coenzyme reduction as a function of time, appeared to be much less for the enzyme adsorbed to the positively charged membrane surface. Moreover, the enzyme adsorbed to the positively charged membrane was the least responsive to pulses of the reducing agent, dithiothreitol, and appeared to exhibit the highest transition temperature when subjected to differential scanning calorimetry analysis. These results indicate that the entropically spreading process observed for other adsorbed proteins may be occurring and the process is more rapid and extensive when enzyme is adsorbed to the nylon than the nitrocellulose membrane. In addition to the relative stability of the enzyme on two different surfaces being examined, the effect of the microenvironment on modulating the activity of the enzyme was investigated by using the reversibility of the enzyme‐catalyzed reaction as a probe of the average local environment of the enzyme. It was found that a threshold buffer concentration existed that, once exceeded, the effect of proton production by the reaction could be suppressed.
Product Inhibition Influence on Immobilized Cell Biocatalyst Performance
Authors: Sayles Gregory D. , Ollis David F.
Published: March 2005

The potential steady‐state influence of product inhibition on the performance of immobilized cell cultures is thoroughly explored with the aid of a simple unstructured reaction‐diffusion model. Production inhibition was assumed to diminish the specific growth rate directly. The range of product sensitivity explored corresponds directly with the observed range of ethanol sensitivity of Clostridium thermocellum, Clostridium ace‐tobutylicum, Saccharomyces uvarum, Zymomonas mobilis, and Saccharomyces cerevisiae. The consequent influence on the immobilized cell growth rate, thickness of steady‐state viable cell layer, formation of growth‐associated product, and global performance of the immobilized cell particle is explored by simulated variation of both the external bulk solution product level and the cell intrinsic sensitivity to the inhibitory product. Thus, both the thickness of the steady‐state viable cell layer and the consequent biomass loading of the bead are predicted variables of the model; these are variables due to the adaptive growth and biomass redistribution which occur in porous supports. The calculated influences are appreciable and even dramatic under some circumstances; the implications for packed‐bed reactor operations for ethanol and solvent production are discussed.

These model calculations indicate that product inhibition can very significantly influence the performance of immobilized cell particles. Immobilization alone necessarily increases the impact of product inhibition on the culture since intraparticle product levels must be higher that external solution conditions. The presence of product inhibition lowers the specific growth rate of the culture pointwise in the carrier, thus diminishing the particle conversion of substrate to product and the total productivity and specific activity of the biocatalyst. Counterintuitively, perhaps, increased sensitivity to product inhibition results at first in an increased viable biomass loading of each carrier particle; then at still higher sensitivities a decreased loading and eventual extinction of viable cells is predicted. The application of these calculations for packed‐bed reactor design is suggested and constitutes a portion of our ongoing studies.
Enhancing Oxygen Transfer in Surface‐Aerated Bioreactors by Stable Foams
Authors: Ju Lu‐Kwang , Armiger William B.
Published: March 2005

To enhance oxygen transfer in surface‐aeration bioreactors, stabilized foams were generated to increase the gas‐liquid interfacial area by slowly introducing coarse bubbles into media containing fetal bovine serum. The bubble sparging rates were so low (i.e., 20 and 50 mL/h) that the contribution to oxygen transfer from these bubbles was due to foaming instead of bubbling. Furthermore, no physical cell damage caused by bubble sparging was observed. Oxygen transfer coefficients, kLa, in the bioreactors were measured in cell‐free media. Without the foam‐stabilizing agent (i.e., serum), no appreciable change in kLa was observed due to the bubble sparging. On the other hand, with serum, kLa increased with increasing serum content and bubble sparging rate and corresponded well with the degree of foaming. With 10% fetal bovine serum and a bubble sparging rate of 50 mL/h, kLa increased approximately 90% compared with no foaming. The enhancing effect of foam on oxygen transfer in surface aeration bioreactors has been further demonstrated with hybridoma cultures simultaneously grown in three identical bioreactors with and without stabilized foams.
Disintegration of Yeast Cells by Pressurized Carbon Dioxide
Authors: Lin Ho‐Mu , Chan Err‐Cheng , Chen Cheeshan , Chen Li‐Fu
Published: March 2005

Disruption of yeast cells with high‐pressure carbon dioxide at both subcritical and supercritical temperatures (25, 35, and 55 °C) was investigated. The experimental results revealed that yeast cells can be ruptured to a maximal level by carbon dioxide within 5 h at 5000 psi and 15 h at 1000 psi at any of the temperatures studied. In the presence of β‐glucuronidase, the length of time for maximal cell rupture was reduced to 90 min at 5000 psi. Off‐flavors of the ruptured yeast cells were removed by carbon dioxide in the process. The functional properties of proteins were preserved, as indicated by enzyme activities in the ruptured cell suspension. An increase in temperature from subcritical to supercritical of carbon dioxide led to a significant enhancement of rapture rates under high pressures, while the functional properties of proteins and the removal of off‐flavors were relatively insensitive to the variation of temperature if the process was maintained at or below 35 °C. At higher temperatures, the activities of enzymes began to decay and were lost at about 55 °C under the carbon dioxide pressures of this study.