bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of quantum chemical descriptors by chemometric methods in the study of antioxidant activity of flavonoid compounds
Authors: Weber K. C. , Honório K. M. , Da Silva S. L. , Mercadante R. , da Silva A. B. F. 
Published: April 2005

AbstractIn the present study, the aim was to select electronic properties responsible for free radical scavenging ability of a set of 25 flavonoid compounds employing chemometric methods. Electronic parameters were calculated using the AM1 semiempirical method, and chemometric methods (principal component analysis, hierarchical cluster analysis, and k‐nearest neighbor) were used with the aim to build models able to find relationships between electronic features and the antioxidant activity presented by the compounds studied. According to these models, four electronic variables can be considered important to discriminate more and less antioxidant flavonoid compounds: polarizability (α), charge at carbon 3 (QC3), total charge at substituent 5 (QS5), and total charge at substituent 3′ (QS3′). The features found as being responsible for the antioxidant activity of the flavonoid compounds studied are consistent with previous results found in the literature. The results obtained can also bring improvements in the search for better antioxidant flavonoid compounds. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Theoretical investigation of optical properties in oligo(trans‐1,2‐di(2‐thienyl) ethylene)
Authors: Marçal Nei , Laks Bernardo 
Published: March 2005

AbstractThe electronic structures of poly(trans‐1,2‐di(2‐thienyl)ethylene) (PTE) oligomers were theoretically analyzed following models based on neutral and charged oligomers for 1 < n < 7. Geometrical optimizations were carried out at the semiempirical level using parametric method 3 (PM3). For singly oxidized oligomer, the positive charge is concentrated around two central monomers. For doubly oxidized oligomer, the positive charge is concentrated around four central monomers. The energy of the electronic transitions and their associated oscillator strength values were also calculated for neutral and charged oligomers, so the UV‐vis absorption spectra is presented. The calculations were done using the intermediate neglect of differential overlap Hamiltonian in combination with the single configuration‐interaction technique in order to include correlations effects. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Energy lowering of current‐carrying single‐particle states in open‐shell atoms due to an exchange‐correlation vector potential
Authors: Orestes E. , da Silva A. B. F. , Capelle K. 
Published: April 2005

AbstractCurrent density functional theory is used to calculate perturbatively the single‐particle energies of open‐shell atoms prepared in a current‐carrying state. We focus on the highest occupied such energy, because its negative is, in principle, the exact ionization energy. A variety of different density functionals and calculational schemes are compared with each other and with experiment. When the atom is prepared in a current‐carrying state, a current‐dependent exchange‐correlation functional is found to slightly lower the single‐particle energy of the current‐carrying orbital, as compared with a calculation using standard (current independent) density functionals for the same system. The current‐dependent terms in the exchange‐correlation functional thus provide additional stabilization of the current‐carrying state. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Erratum: Titanium oxides and silicates as high‐κ dielectrics: A first‐principles investigation by G.‐M. Rignanese, X. Rocquefelte, X. Gonze, Alfredo Pasquarello
Authors: Rignanese G.‐M. , Rocquefelte X. , Gonze X. , Pasquarello Alfredo 
Published: March 2005

AbstractThe original article to which this Erratum refers was published in International Journal of Quantum Chemistry (2005) 101(6) 793– 801
In vivo specificity of Ure2 protection from heavy metal ion and oxidative cellular damage in Saccharomyces cerevisiae
Authors: Rai Rajendra , Cooper Terrance G. 
Published: April 2005

AbstractThe S. cerevisiae Ure2 protein is a prion precursor able to form large homopolymers with the characteristics of amyloid particles, a function largely restricted to its 90 N‐terminal amino acids. The remaining C‐terminal domain of Ure2 plays two important roles in cellular metabolism. First, it regulates nitrogen catabolic gene expression by forming a complex with the GATA transcription factor Gln3. This complex formation correlates with Gln3 being sequestered in the cytoplasm under conditions of excess nitrogen, where Gln3/Gat1‐mediated transcription is minimal. Second, Ure2, which possesses structural homology with glutathione S‐transferases and binds to xenobiotics and glutathione, has been recently shown to be required for Cd(II) and hydrogen peroxide detoxification. Present experiments demonstrate that Ure2 possesses a far broader protection specificity, being required to avoid the toxic effects of As(III), As(V), Cr(III), Cr(VI), Se(IV), as well as Cd(II) and Ni(II), and to varying lesser degrees Co(II), Cu(II), Fe(II), Ag(I), Hg(II), cumene and t‐butyl hydroperoxides. In contrast, deletion of URE2 greatly enhances a cell's ability to withstand toxic concentrations of Zn(II) and Mo(VI). In the case of Cd(II), Ure2 does not function to decrease intracellular Cd(II) levels or influence glutathione availability for glutathionation. In fact, ure2 hypersensitivity to Cd(II) remains the same, even when glutathione is used as sole source of nitrogen for cell growth. These data suggest that Ure2 possesses a central role in metal ion detoxification, a role not demonstrably shared by either of the two known S. cerevisiae glutathione S‐transferases, Gtt1 and Gtt2, or the two glutaredoxins, Grx1 and Grx2, that also possess glutathione S‐transferase activity. Copyright © 2005 John Wiley & Sons, Ltd.
SFP1 is involved in cell size modulation in respiro‐fermentative growth conditions
Authors: Cipollina Chiara , Alberghina Lilia , Porro Danilo , Vai Marina 
Published: April 2005

AbstractSaccharomyces cerevisiae grows fast on glucose, while growth slows down on ethanol as cells move from glucose fermentation to oxidative metabolism. The type of carbon source influences both the specific growth rate and cell cycle progression, as well as cell size. Yeast cells grown on glucose have a larger size than cells grown on ethanol. Here, we analysed the behaviour of a sfp1 null mutant during balanced and transitory states of growth in batch in response to changes in the growth medium carbon sources. In a screening for mutants affected in cell size at Start, SFP1 has been identified as a gene whose deletion caused one of the smallest whi phenotype. Findings presented in this work indicate that in the sfp1 null mutant the reduction in cell size is not only a consequence of the reduced growth rate but it is tightly linked to the cellular metabolism. The SFP1 gene product is required to sustain the increase of both rRNA and protein content that in wild‐type cells takes place in respiro‐fermentative growth conditions, while it seems dispensable for growth on non‐fermentable carbon sources. It follows that sfp1 cells growing on ethanol have a larger size than cells growing on glucose and, noticeably, the former enter the S phase with a critical cell size higher than the latter. These features, combined with the role of Sfp1p as a transcriptional factor, suggest that Sfp1p could be an important element in the control of the cell size modulated by nutrients. Copyright © 2005 John Wiley & Sons, Ltd.
Homotopical localizations of module spectra
Authors: Casacuberta Carles , Gutiérrez Javier 
Published: March 2005

We prove that stable

f
f

-localizations (where

f
f

is any map of spectra) preserve ring spectrum structures and module spectrum structures, under suitable hypotheses, and we use this fact to describe all possible localizations of the integral Eilenberg–Mac Lane spectrum

H

Z

H{\mathbb {Z}}

. As a consequence of this study, we infer that localizations of stable GEMs are stable GEMs, and it also follows that there is a proper class of nonequivalent stable localizations.
Cycles on curves over global fields of positive characteristic
Authors: Akhtar Reza 
Published: March 2005

Let

k
k

be a global field of positive characteristic, and let

σ
:
X
⟶
Spec
⁡
k

\sigma : X \longrightarrow \operatorname {Spec} k

be a smooth projective curve. We study the zero-dimensional cycle group

V
(
X
)
=
Ker
⁡
(

σ
∗

:
S

K
1

(
X
)
→

K
1

(
k
)
)

V(X) =\operatorname {Ker}(\sigma _*: SK_1(X) \rightarrow K_1(k))

and the one-dimensional cycle group

W
(
X
)
=
coker
⁡
(

σ
∗

:

K
2

(
k
)
→

H

Z
a
r

0

(
X
,

K

2

)
)

W(X) =\operatorname {coker}(\sigma ^*: K_2(k) \rightarrow H^0_{Zar}(X, \mathcal {K}_2))

, addressing the conjecture that

V
(
X
)

V(X)

is torsion and

W
(
X
)

W(X)

is finitely generated. The main idea is to use Abhyankar’s Theorem on resolution of singularities to relate the study of these cycle groups to that of the

K
K

-groups of a certain smooth projective surface over a finite field.
On nonlinear wave equations with degenerate damping and source terms
Authors: Barbu Viorel , Lasiecka Irena , Rammaha Mohammad 
Published: March 2005

In this article we focus on the global well-posedness of the differential equation

u

t
t

−
Δ
u
+

|

u

|

k

∂
j
(

u
t

)
=

|

u

|

p
−
1

u

in
Ω
×
(
0
,
T
)

u_{tt}- \Delta u + |u|^k\partial j(u_t) = |u|^{ p-1}u \, \text { in } \Omega \times (0,T)

, where

∂
j

\partial j

is a sub-differential of a continuous convex function

j
j

. Under some conditions on

j
j

and the parameters in the equations, we obtain several results on the existence of global solutions, uniqueness, nonexistence and propagation of regularity. Under nominal assumptions on the parameters we establish the existence of global generalized solutions. With further restrictions on the parameters we prove the existence and uniqueness of a global weak solution. In addition, we obtain a result on the nonexistence of global weak solutions to the equation whenever the exponent

p
p

is greater than the critical value

k
+
m

k+m

, and the initial energy is negative. We also address the issue of propagation of regularity. Specifically, under some restriction on the parameters, we prove that solutions that correspond to any regular initial data such that

u
0

∈

H
2

(
Ω
)
∩

H
0
1

(
Ω
)

u_0\in H^2(\Omega )\cap H^1_0(\Omega )

,

u
1

∈

H
0
1

(
Ω
)

u_1 \in H^1_0(\Omega )

are indeed strong solutions.
Immunohistochemical Evaluation of p53 Expression and Proliferative Activity in Children with Helicobacter pylori Associated Gastritis
Authors: Ozturk Yesim , Ozer Erdener , Lebe Banu , Bekem Ozlem , Buyukgebiz Benal 
Published: March 2005

ABSTRACTObjectives:The aim of this study was to evaluate the significance of p53 expression and proliferative activity of glandular epithelium and intestinal metaplasia in Helicobacter pylori associated gastritis of pediatric patients.Methods:The study included endoscopic gastric biopsies of 54 children with dyspeptic complaints. Immunohistochemistry was performed for evaluation of p53 expression and Ki‐67 labeling index, an indicator of proliferative activity. Grading of H. pylori density, intestinal metaplasia and inflammatory cell infiltration were performed in histologic tissue sections stained with hematoxylin‐eosin, Giemsa and Alcian‐blue.Results:Of 54 children, 35 (64%) were infected by H. pylori. Positive immunostaining for p53 was observed in 11 of 54 cases (20.4%). H. pylori infection was found in 10 (91%) of the p53‐positive patients. There was a positive correlation between H. pylori density and Ki‐67 labeling index in H. pylori infected children. H. pylori density, Ki‐67 labeling index and inflammatory cell infiltration in the p53‐positive group were significantly higher than in the p53‐negative group. Although intestinal metaplasia was more common in H. pylori infected children (n = 11; 31.4%), there was no difference in the rate of intestinal metaplasia between the p53‐positive and p53‐negative groups.Conclusions:The present study shows that p53 mutations and higher proliferative activity of glandular epithelium may be related to H. pylori associated gastritis in children. Because p53 mutation does not appear to be associated with intestinal metaplasia, a precursor for gastric cancer in adults, we think that H.pylori associated p53 alterations do not initiate and promote gastric cancer that may occur in adulthood.
Free Amino Acids in Full‐Term and Pre‐Term Human Milk and Infant Formula
Authors: Chuang Chih‐Kuang , Lin Shuan‐Pei , Lee Hung‐Chang , Wang Tuen‐Jen , Shih Yu‐Shu , Huang Fu‐Yuan , Yeung Chun‐Yan 
Published: March 2005

ABSTRACTObjective:Although the nutritional value of human milk has been thoroughly studied, few reports describing its free amino acid (FAA) content have been published. Although infant formulas are designed to approximate the nutrient composition of human milk, the content and concentration of free amino acids are unknown. We compared the FAA concentrations of milk from mothers of preterm and full‐term infants with those in several infant formulas.Method:Human milk was obtained during three different stages of lactation (colostral, transitional and mature milk). Sixty‐seven samples were collected from 44 healthy mothers of term infants and 23 mothers of premature infants 29 to 36 weeks gestation (mean 33 weeks). Two brands of powdered term formula (TF‐A and TF‐B) and two brands designed for preterm infants (PTF‐A and PTF‐B) were also studied. Ion exchange chromatography was used for free amino acid analysis.Results:The mean concentration of total FAA in human milk was significantly higher than any of the infant formulas (8139 μmol/L for pre‐term human milk; 3462 μmol/L for full term human milk; TF‐A, 720 μmol/L; TF‐B, 697 μmol/L; PTF‐A, 820 μmol/L; PTF‐B, 789 μmol/L) (P <0.01). FAA concentration in term and premature human colostral milk was significantly higher than in human transitional and mature milks (P <0.01). In comparing individual FAAs, there were significant differences in concentrations between term human milk and preterm milk except for phosphoethanolamine, hydroxyproline, asparagine, and α‐amino‐η‐butyric acid. There were significant differences in all FAA concentrations between all human milks and infant formulas (P <0.05), but no significant differences were found among the study formulas.Conclusion:The concentration of FAA is high in human colostral milk and decreases through the transitional and mature milk stages. FAA is higher in all human milks than in infant formulas.
Assessment of the Rectoanal Inhibitory Reflex in Preterm Infants with Delayed Meconium Passage
Authors: de Lorijn F , Voskuijl W P , Omari T I , Kok J H , Taminiau J A. J. M , Benninga M A 
Published: March 2005

ABSTRACTBackground:There is an inverse relationship between gestational age, birth weight and the time of first neonatal bowel movement. The authors hypothesized that delayed passage of meconium might result from a delayed maturation of the recto‐anal inhibitory reflex (RAIR) in premature infants.Objective:To evaluate whether the RAIR is absent in very preterm infants 28‐32 weeks postmenstrual age with delayed meconium production.Study design:Anorectal manometry was performed in 10 preterm infants (seven male) with delayed meconium production (no meconium in the first 48 hours). Median postmenstrual age was 30 weeks (28‐31 weeks). Birth weight ranged from 780 to 1930 g (median, 1395 g). A micromanometric assembly (outer diameter, 2.0 mm) was used which incorporated a 1.5‐cm‐long sleeve sensor for measurement of resting anal sphincter pressure and relaxation. Four side‐holes recorded anal and rectal pressures. Rectal distension was performed with direct air insufflation to elicit the RAIR.Results:The time from birth to passage of meconium ranged from 48 to 105 hours (median, 82 hours). The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 22.0 ± 5.0 mm Hg, 6.9 ± 2.0 mm Hg, and 9.8 ± 1.9/min, respectively. A normal RAIR was elicited in all infants.Conclusion:Anorectal manometry recordings in premature infants with delayed passage of meconium showed normal anorectal pressures and a normal RAIR, suggesting that delayed meconium passage is not related to the absence of a RAIR.
CARD15 Mutations Are Rare in Swedish Pediatric Crohn Disease
Authors: Ideström Maja , Rubio Carlos , Granath Fredrik , Finkel Yigael , Hugot J‐P 
Published: March 2005

ABSTRACTBackground:An association between mutations in a gene involved in bacterial recognition by monocytes, CARD15/NOD2 and Crohn disease (CD) has been reported in studies of adults and children. The aim of this study was to investigate the presence of CARD15 mutations in Swedish children with CD and analyze genotype‐phenotype correlations.Patients and Methods:Fifty‐eight children (62% boys) with CD diagnosed between 2.8 and 16.9 years (median 10.9 years), were reviewed. Histopathology, retrospective data collection and mutational analyses for the three main mutations R702W, G908R and 1007fs were independently performed. First‐degree relatives were also genotyped.Results:A CARD15 mutation was found in 8.6% (95% confidence interval, 2.9% to 19.0%), all of whom were heterozygotes, giving an overall allele frequency of 4.3% (95% confidence interval, 1.4‐9.8). In 12%, all patients without mutations, a first‐degree relative had CD. In four of five children, mutations were transferred from their healthy mothers. Granulomas at onset were found in 80% of patients with mutations and in 43% of those without (P = 0.17). No statistical association was found between mutation and phenotype regarding age at onset, anatomic location at onset or follow‐up, severity of inflammation at onset, development of stenosis, perianal disease or extra intestinal manifestations.Conclusions:The frequency of CARD15 mutation in this Swedish pediatric CD population is lower than reported in a mixed adult and pediatric population. The genotype‐phenotype correlations were non‐significant although a trend was found between the presence of mutations and granuloma formation. Healthy heterozygote mothers conveyed the mutation to their children with CD.
Sludge Ball, Pseudolithiasis, Cholelithiasis and Choledocholithiasis from Intrauterine Life to 2 Years: A 13‐Year Follow‐Up
Authors: Klar Aharon , Branski David , Akerman Yaacov , Nadjari Michael , Berkun Yaacov , Moise Jonathan , Shazberg Gila , Revel‐Vilk Shoshana , Israeli Talia , Katz Gabriel , Levy Arie , Ami Anat Ben , Hurvitz Haggit 
Published: March 2005

ABSTRACTObjective:Evaluation and follow‐up of infants with cholelithiasis and pseudolithiasis in a pediatric ward.Patients & Methods:Prospective study from April 1990 to October 2003 identified hospitalized infants younger than 2 years with ultrasonographic findings of cholelithiasis, choledocholithiasis or pseudolithiasis. Associated abnormalities or contributory factors were recorded and patients were followed for from 6 months to 13 years (mean, 4 years).Results:Thirty‐four patients were diagnosed between the age of 3 weeks and 24 months. Thirteen (38%) had been treated with third‐generation cephalosporins. Other associated factors were dehydration in 10 (29%), urinary tract infection in two (6%) and one each for cholestatic liver disease, total parenteral nutrition, immunoglobulin A deficiency and prematurity. Six infants (17%) had no known risk factor. Six additional patients were diagnosed by antenatal ultrasound.Conclusions:Cholelithiasis in infants hospitalized for a variety of common pediatric conditions is not rare. Dehydration and treatment with third‐generation cephalosporins are important associated factors. The classic risk factors of hemolysis and previous gastrointestinal surgery, were not found in our group. The overall prognosis was good. Pseudolithiasis disappeared in all infants. Of the 21 infants with cholelithiasis, only two developed cholecystitis. In nine infants, spontaneous resolution occurred. In the absence of other clinical or imaging evidence of biliary tract disease, conservative management is advised.
Digestive Endoscopy in Neonates
Authors: Dupont Christophe , Kalach Nicolas , de Boissieu Delphine , Barbet Jacques Patrick , Benhamou Pierre‐Henri 
Published: March 2005

ABSTRACTSince the introduction of flexible fiberoptic endoscopy in the early 1970s, esophagogastro‐duodenoscopy and colonoscopy have become established procedures for the diagnosis, evaluation and treatment of gastrointestinal tract disease in the pediatric population. The development of safe fiberoptic endoscopes specially designed for neonates has allowed visualization of lesions occurring in the first days of life. Despite an increased understanding of neonatal digestive disorders deriving from this new diagnostic modality, there is little consensus on the appropriate use of endoscopic procedures in routine care of neonates. It is the feeling of the authors that widening the indications of endoscopy in the neonatal period might lead to diagnosis of discrete clinical abnormalities, which might improve the care of neonates. The techniques for performing neonatal endoscopies, the appropriate indications, the common normal and pathologic findings and the complications of these procedures are reviewed
Colorectal Inflammation is Well Predicted by Fecal Calprotectin in Children with Gastrointestinal Symptoms
Authors: Fagerberg Ulrika Lorentzon , Lööf Lars , Myrdal Urban , Hansson Lars‐Olof , Finkel Yigael 
Published: March 2005

ABSTRACTObjectives:The protein calprotectin is mainly derived from neutrophils. Increased fecal excretion of calprotectin has been reported in inflammatory bowel disease. The recommended cut‐off level in adults (<50 μg/g feces) seems to be applicable in children aged 4 to 17 years. The aim of this study was to evaluate the use of fecal calprotectin to detect colorectal inflammation in children with gastrointestinal symptoms.Methods:We obtained stool samples on thirty‐six children with gastrointestinal symptoms and suspected inflammation of the colon before they underwent colonoscopy. The samples were examined with an improved fecal calprotectin enzyme‐linked immunosorbent assay method (Calprest®, Eurospital). The results were correlated with the histopathologic findings in the colon.Results:In children with colorectal inflammation (n = 22) the median fecal calprotectin concentration was 349 μg/g (range, 15.4‐1860 μg/g). The most common diagnosis in this group was inflammatory bowel disease. Median fecal calprotectin was 16.5 μg/g (range, 5.0‐65 μg/g) in children with no inflammation (n = 14). When <50 μg/g was used as upper reference limit the fecal calprotectin test had a sensitivity of 95%, specificity 93%, positive predictive value 95% and negative predictive value 93% to detect colorectal inflammation.Conclusions:The improved fecal calprotectin enzyme‐linked immunosorbent assay is a simple test with potential use in children. Increased fecal calprotectin strongly predicted the presence of colorectal inflammation in children with gastrointestinal symptoms. Fecal calprotectin can be used to select patients who should undergo diagnostic colonoscopy for investigation of colorectal inflammation, including inflammatory bowel disease.