bluuebunny/crossref_metadata_2025_split huggingface dataset:
Addressing nonscientific presuppositions in genetics using a conceptual change strategy
Authors: Mbajiorgu N. M. , Ezechi N. G. , Idoko E. C. 
Published: February 2007

AbstractResearchers are becoming aware of the influence of students' presuppositions in directing their construction of science concepts. When these are entrenched and drastically nonscientific, they predispose the children to alternative explanatory frameworks that are inhibiting, especially in a knowledge domain such as genetics. In this study, we identified such nonscientific presuppositions among 17‐ to 18‐year‐old secondary school students from the Igbo community of Southeastern Nigeria. We designed a research‐based instructional model to address these presuppositions. The relationship between the levels of nonscientific presuppositions held by students and their achievement in genetics was assessed. Finally, the effect of the instructional model on students' relinquishing these nonscientific presuppositions and on their achievement was determined relative to a comparison group. It was found that this group of students had nonscientific presuppositions that they used in explaining genetic phenomena, and that the present instructional model aided the students in relinquishing these nonscientific presuppositions to a great extent. We conclude that a conceptual change model that addresses explicitly nonscientific presuppositions will lead to an increased understanding of science concepts. © 2007 Wiley Periodicals, Inc. Sci Ed 91:419–438, 2007
Positron backscattering from an Al target: analytical calculation and Monte Carlo simulation
Authors: Bentabet A. , Bouarissa N. 
Published: February 2007

AbstractPositron backscattering coefficients are analytically calculated and numerically simulated for an Al target in the positron energy range 0.50–4 keV and for incident angles between 0° and 80° . The differential elastic scattering cross section has been obtained using the Bentabet and Bouarissa approximation (Phys. Lett. 2006; A 355: 390). Both the analytical and simulated results show good agreement with the experiment and previous theoretical work. Copyright © 2007 John Wiley & Sons, Ltd.
Rice Starch Molecular Size and its Relationship with Amylose Content
Authors: Park In Myoung , Ibáñez Ana Maria , Shoemaker Charles F. 
Published: February 2007

AbstractThe composition and starch molecular structure of eight rice varieties were studied. Waxy and non‐waxy (long‐, medium‐, and short‐grain) rice varieties from California and Texas were used. The amylose contents were measured using the Concanavalin A method and were found to be related to the type of rice: waxy ≈ 1.0%, short and medium grain 8.7–15.4%, and long grain 17.1–19.9%. The weight‐average molar masses (Mw) of the starches varied from 0.52 to 1.96×108 g/mol. As would be expected, a higher Mw of rice starch correlated to lower amylose content. The range of Mw of amylopectin was 0.82 to 2.50 ×108 g/mol, and there was also a negative correlation of amylopectin Mw with amylose content. Amylose Mw ranged from 2.20 to 8.31×105 g/mol. After debranching the amylopectin with isoamylase, the weight‐average degree of polymerization (DPw) for the long‐chain fraction correlated positively with a higher amylose content. California and Texas varieties were significantly different in their amylose content, starch Mw (short‐ and medium‐grain only), and amylopectin Mw (p < 0.05).
Vertical stratification of oribatid (Acari: Oribatida) communities in relation to their morphological and life‐history traits and tree structures in a subtropical forest in Japan
Authors: Karasawa Shigenori , Hijii Naoki 
Published: February 2007

AbstractTo clarify the effect of tree structure on the diversity of oribatid mites (Acari: Oribatida), we collected a total of 16,325 oribatids in 181 morphospecies from the leaves, branches, and trunk bark of trees and from the forest‐floor soil and litter in a subtropical forest, Okinawa, Japan, and tested three predictions: (1) moisture stress in arboreal habitats would lead to larger body size (not supported); (2) morphological traits related to gripping a surface (number and size of claws) would be more developed in arboreal species (supported); and (3) advantages in colonization (no cost for searching mates and doubled population growth) would favor parthenogenesis in the arboreal oribatid communities (not supported). We observed vertical stratification among the five habitats in terms of mite density, species diversity, and species composition, but found no difference in the body length of oribatid species between the arboreal and forest‐floor habitats. However, (homo‐)tridactylous species predominated in the arboreal habitat, suggesting that this claw morphology facilitates adherence to and movement on arboreal substrates. Sexual species were common in the arboreal oribatid communities, whereas about half of the dominant species collected from the forest floor were likely to be parthenogenetic. It is unclear how these different reproductive systems may be advantageous for oribatid mites in arboreal and forest‐floor habitats. Nevertheless, the structural complexity provided by trees appears to enhance and maintain the diversity of oribatid communities through vertical stratification in this subtropical forest.
A novel approach to ultrasensitive diagnosis using supramolecular protein nanoparticles
Authors: Lee Sung-Hyun , Lee Hyewon , Park Jin-Seung , Choi Hyoung , Han Kyung-Yeon , Seo Hyuk-Seong , Ahn Keum-Young , Han Sung-Sik , Cho Yunjung , Lee Kee-Hyoung , Lee Jeewon 
Published: February 2007

ABSTRACTWe report on the ultrasensitive protein nanoprobe system that specifically captures disease marker (autoantibodies of Type I diabetes in this case) with attomolar sensitivity. The system relies on supramolecular protein nanoparticles that bind a specific antibody [65 kDa glutamate decarboxylase (GAD65)‐specific autoantibody, i.e., the early marker of Type I diabetes]. The ultrasensitive detection of early marker of Type I diabetes during the early phase of pancreatic β‐cell destruction is important because individuals at high risk of developing Type I diabetes can be identified several years before the clinical onset of the ailment. The bacterial expression of chimera genes encoding N‐[human ferritin heavy chain (hFTN‐H)]::[specific antigenic epitope]‐C produces supramolecular nanoparticles with uniform diameters (10‐15 nm), owing to self‐assembly activity of hFTN‐H. Each nanoparticle, formed by intermolecular self‐assembly between the chimera protein molecules, is subjected to carrying a large number (presumably, 24) of epitopes with a homogeneous and stable conformation per autoantibody binding, thereby allowing substantial enhancement of sensitivity. The sensitivity was finally boosted to 3 attomolar concentration of the autoantibodies, 4‐9 orders of magnitude more sensitive than conventional immunoassays. Also, this ultrasensitive protein nanoprobe successfully detected natural autoantibodies in the sera from Type I diabetic patients. The attomolar sensitivity was successfully reproduced on the detection of other antibodies, i.e., monoclonal antibodies against hepatitis B surface antigen. With the two antibody markers above, the feasibility of simultaneous and multiplexing‐mode detection was also demonstrated.—Lee S‐H., Lee, H., Park J‐S., Choi, H., Han K‐Y., Seo H‐S., Ahn K‐Y., Han S‐S., Cho, Y., Lee K‐H., Lee J. A novel approach to ultrasensitive diagnosis using supramolecular protein nano‐particles. FASEB J. 21, 1324–1334 (2007)
Elastic‐plastic fracture mechanics assessment for steam generator tubes with through‐wall cracks
Authors: HUH NAM‐SU , KIM JONG‐MIN , CHANG YOON‐SUK , KIM YOUNG‐JIN , HWANG SEONG‐SIK , KIM JOUNG‐SOO 
Published: February 2007

ABSTRACTSThe present work provides an elastic‐plastic fracture mechanics (EPFM) assessment scheme for a steam generator tube with a through‐wall crack under internal pressure. Noting that the geometry and material are rather uniform for steam generator tubes, and furthermore the only loading to be considered is internal pressure, an engineering EPFM analysis method is proposed to assess through‐wall cracks in steam generator tubes. Important outcomes of the present work are closed‐form approximations for J and crack opening displacement (COD). Sufficient confidence in the proposed J and COD estimates is gained from good agreements with the finite element results over a wide range of the crack length and pressure magnitude. Another important element of the EPFM assessment is to determine relevant J‐resistance curve for steam generator tubes. To improve the accuracy of predicting tube failure, the present paper also proposes a new method to determine fracture toughness using an actual tubular specimen instead of using a standard specimen, from which J‐resistance curves of steam generator tubes are obtained. Using the proposed J and toughness estimates, maximum pressures of steam generator tubes with through‐wall crack are estimated based on EPFM analysis, which is compared with experimental results and predicted ones based on limit load approach.
The cost‐effectiveness of sibutramine in non‐diabetic obese patients: evidence from four Western countries
Authors: Ara R. , Brennan A. 
Published: February 2007

SummaryThis paper aims to assess the cost‐effectiveness of sibutramine in treating obese patients in the Western countries. The model estimates the costs and quality of life benefits directly associated with weight losses combined with the costs and benefits associated with the reduced incidence of coronary heart disease (CHD) and diabetes. The pivotal effectiveness evidence is derived from a German multicentre, double‐blind, randomized clinical trial on obese (body mass index ≥ €30 kg m−2) patients. The incremental cost per quality‐adjusted life year ranges from €10 734 in Switzerland to €13 707 in Germany. The total number of CHD events avoided ranges from 1.96 for the UK to 4.49 for Switzerland. The number of diabetes cases avoided is in the region of 3.0 (ranges from 2.58 for Germany to 3.28 for Switzerland). The majority of costs and benefits are accrued through sibutramine treatment and monitoring. Univariate sensitivity analyses show that results are sensitive to changes in the utility directly attributable to weight losses. The results demonstrate that the benefits associated with sibutramine‐induced weight losses are obtained at a reasonable cost in each of the settings explored and suggest that sibutramine treatment could be considered as a viable option for pharmacotherapy treatment alongside diet and exercise.
Telangiectasia Macularis Eruptiva Perstans: Unusual Presentation and Treatment
Authors: Rishpon Ayelet , Matz Hagit , Gat Andrea , Brenner Sarah 
Published: February 2007

A 41‐year‐old woman presented with a 2‐month history of pruritus and a generalized dermatitis that developed initially on the head and spread to the trunk, legs, and buttocks. The pruritus caused extreme discomfort and was not relieved by antihistamines or topical steroid treatment. The patient denied flushing, syncope, and vomiting. Her medical history included asthma treated with salmeterol/fluticasone propionate inhaler, and status post silicone breast augmentation. Physical examination revealed a papular dermatitis on the trunk and extremities composed of lesions up to O.S cm in diameter, surrounded by excoriation marks (Figure 1). There was no hepatosplenomegaly or lymphadenopathy. Darier's sign was negative. Results of complete blood count, peripheral blood film examination, and liver function tests were all with normal limits. A biopsy specimen taken from a lesion and stained with hematoxylin‐eosin showed telangiectasias, with an increased number of mast cells around blood vessels (Figure 2). Positive Giemsa (Figure 3) and c‐kit stain (Figure 4) indicated an increased number of mast cells. Bone marrow aspiration and total body CT performed to rule out systemic involvement showed no pathology. Protein electrophoresis was normal. Serum tryptase and histamine were within normal limits, and 24‐hour urine collection for histamine was normal. Narrow‐band UV‐B treatment was begun 3 times weekly, reduced to twice weekly after 2 months, and then stopped. The first few treatments resulted in significant relief of the pruritus and regression of lesions. After 3 months without treatment, the patient remained free of pruritus and lesions. Patient before treatment; skin showing papular dermatitis and excoriation marks. image Skin specimen showing telangiectasias and moderately dense perivascular infiltrate composed of lymphocytes, eosinophils, and mast cells (hematoxylineosin stain; original magnification ×10). image Giemsa stain highlighting cytoplasmic mast cell granules (original magnification ×40). image C‐kit (CD117) stain highlighting mast cells (original magnification ×20). image
Bite the Hand That Sprays You
Authors: Ismailjee Sameer B. , Bernstein Jack M. , Burdette Steven D. 
Published: February 2007

A 56‐year‐old man presented with a cutaneous lesion on his right hand (Figure 1). Approximately 6 weeks previously, he had traveled to Costa Rica for missionary work. During his travel he used a diethyltoluamide‐containing insect repellant, but spent one night in the jungle without a mosquito net. Four weeks after his return, he noted a 3 × 2.5‐cm ulcer with raised edges and surrounding erythema on the dorsum of his right hand. The patient recalled applying insect repellant with his right hand to other exposed areas of his body but was remiss in applying it to the right hand itself. On examination, the patient was noted to have an ulcerated nodule near his right earlobe (Figure 2) and a second 2 × 1‐cm ulcer on the volar aspect of his right wrist (Figure 3). There were no mucocutaneous lesions noted. During the next several weeks, numerous nodules developed in a sporotrichoid pattern on the extensor surface of his right arm (Figure 4). Skin biopsy was performed at the time of initial evaluation and revealed cutaneous leishmaniasis due to Leishmania panamensis. After discussing the different treatment options, miltefosine was administered orally for 28 days. The patient experienced an excellent response to therapy. Ulcer, dorsum, right hand. image Eschar, anterior to right ear. image Ulcer, volar surface, right forearm. image Sporotrichoid lesions, right forearm. image
Perinuclear Antineutrophil Cytoplasmic Antibody‐Associated Vasculitis in a Patient With Graves' Disease Treated With Methimazole
Authors: Martin Donna Bilu , Deng April , Gaspari Anthony , Pearson Frederick 
Published: February 2007

A 15‐year‐old Caucasian girl presented with a 1‐week history of necrotic ulcers on her bilateral lower extremities, associated with fever and malaise. She had had similar ulcerations on and off over the past 3 years. She had a medical history of Graves' disease, diagnosed in 1999, for which she was taking methimazole (MMI). On physical examination, there were multiple necrotic ulcers with elevated, inflamed borders and an overlying eschar on the bilateral distal extremities (Figure 1). There was one hemorrhagic, flaccid bulla on the lateral aspect of the ankle. Her complete blood count, comprehensive metabolic panel, prothrombin time, and international normalized ratio were within normal limits. Histopathology revealed a neutrophilic vasculitis involving small as well as medium‐sized blood vessels. The overlying epidermis and upper dermis showed necrosis (Figure 2). Antinuclear antibody (ANA) was positive at 1:160. Perinuclear (p‐) antineutrophil cytoplasmic antibody (ANCA) was positive at 1:320. Cytoplasmic ANCA was negative. The patient did not meet any clinical criteria for a diagnosis of lupus erythematosus. Direct immunofluorescence revealed IgM, complement C3, and fibrin in small‐ and medium‐caliber blood vessels in the dermis, consistent with a leukocytoclastic vasculitis of small‐ and medium‐caliber blood vessels (Figure 3). MMI was stopped and the patient was given prednisone, tapered over 5 days. Her thyroid function remained stable, and she did not develop new necrotic ulcers. One month later, the patient developed urticarial lesions on her lower extremities. Histopathology revealed a lymphocytic vascular reaction. No eosinophils or neutrophils were seen. These newer urticarial lesions resolved. The patient underwent debridement of the thick, necrotic ulcerative eschars. To date, her lesions have resolved (Figure 4). An ANA drawn S months after withdrawal of MMI was negative, and p‐ANCA was 1:67. On initial physical examination, there were multiple necrotic ulcers with elevated, inflamed borders and an overlying eschar on the bilateral distal extremities. image Neutrophilic vasculitis involving small as well as medium‐sized blood vessels. The overlying epidermis and upper dermis showed necrosis and dermolysis. There is necrosis in the vessels. Hematoxylin and eosin stain; original magnification ×7 00. image Direct immuno‐fluorescence revealed IgM, complement C3, and fibrin in small‐ and medium‐caliber blood vessels in the dermis, consistent with a leukocytoclastic vasculitis of small‐ and medium‐caliber blood vessels. Fluorescein‐conjugated goat antihuman IgM stain; original magnification ×200. image On 5‐month follow‐up, the ulcers have nearly completely healed. image
Mitogen‐activated protein kinases mediate interleukin‐1β‐induced receptor activator of nuclear factor‐κB ligand expression in human periodontal ligament cells
Authors: Oikawa A. , Kobayashi M. , Okamatsu Y. , Shinki T. , Kamijo R. , Yamamoto M. , Hasegawa K. 
Published: February 2007

Background and Objective:  Interleukin‐1β‐stimulated receptor activator of nuclear factor‐κB ligand (RANKL) expression in human periodontal ligament cells is partially mediated by endogenous prostaglandin E2, whereas mitogen‐activated protein kinases (MAPKs) are implicated in regulating various interleukin‐1‐responsive genes. We investigated herein the involvement of MAPKs in interleukin‐1β‐stimulated RANKL expression in human periodontal ligament cells.Material and Methods:  Human periodontal ligament cells were pretreated separately with specific inhibitors of MAPKs, including extracellular signal‐regulated kinase, p38 MAPK and c‐Jun N‐terminal kinase, and subsequently treated with interleukin‐1β. Following each treatment, the phosphorylation of each MAPK, the expression of RANKL, and the production of prostaglandin E2 were determined. RANKL activity was evaluated using an assay to determine the survival of prefusion osteoclasts.Results:  Interleukin‐1β induced RANKL expression at the mRNA and protein levels, as well as RANKL activity in human periodontal ligament cells. Interleukin‐1β also activated extracellular signal‐regulated kinase, p38 MAPK, and c‐Jun N‐terminal kinase. Pretreatment with each MAPK inhibitor partially, but significantly, suppressed interleukin‐1β‐induced RANKL expression and its activity, as well as prostaglandin E2 production.Conclusion:  In human periodontal ligament cells, three types of MAPK inhibitor may abrogate RANKL expression and activity induced by interleukin‐1β, directly or indirectly through partial suppression of prostaglandin E2 synthesis. In addition, extracellular signal‐regulated kinase, p38 MAPK, and c‐Jun N‐terminal kinase signals may co‐operatively mediate interleukin‐1β‐stimulated RANKL expression and its activity in those cells.
Species-Specific Differences in the Susceptibilities of Biofilms Formed by
Candida
Bloodstream Isolates to Echinocandin Antifungals
Authors: Choi Hyun Woo , Shin Jong Hee , Jung Sook In , Park Kyung Hwa , Cho Duck , Kee Seung Jung , Shin Myung Geun , Suh Soon Pal , Ryang Dong Wook 
Published: February 2007

ABSTRACT

The echinocandin susceptibilities of bloodstream
Candida
isolates growing in a biofilm was investigated. Within the therapeutic range of concentrations of each drug, caspofungin and micafungin were active against biofilms formed by
Candida albicans
or
C. glabrata
but not those formed by
C. tropicalis
or
C. parapsilosis
.
Common Origin and Fixation of
Plasmodium falciparum dhfr
and
dhps
Mutations Associated with Sulfadoxine-Pyrimethamine Resistance in a Low-Transmission Area in South America
Authors: McCollum Andrea M. , Mueller Kristen , Villegas Leopoldo , Udhayakumar Venkatachalam , Escalante Ananias A. 
Published: February 2007

ABSTRACT

Recent studies indicated that sensitive parasites could increase in frequency in a population when drugs are removed, suggesting that the life span of affordable antimalarial drugs could be expanded. We studied 97 samples from Bolivar State, Venezuela, an area where sulfadoxine-pyrimethamine (SP) has not been used for 8 years due to its ineffectiveness. We characterized point mutations in two genes that have been implicated in resistance to SP, dihydrofolate reductase (
dhfr
) and dihydropteroate synthase (
dhps
). We also assayed neutral microsatellite markers around the
dhfr
(chromosome 4) and
dhps
(chromosome 8) genes and on chromosomes 2 and 3 to track the origin and spread of resistant alleles. We found that drug-resistant SP mutants are fixed in the population. Two genotypes were present in the samples,
dhfr
(
50R
/
51I
/
108N
)
dhps
(
437G
/
540E
/
581G
) (90.7%) and
dhfr
(
51I
/
108N
)
dhps
(
437G
/
581G
) (9.3%). We show a single microsatellite haplotype for all of the
dhfr
and
dhps
alleles, and the alleles at the microsatellite loci are different from those present in Africa. Thus, in these samples from Venezuela, there is a single origin for both
dhfr
and
dhps
SP-resistant alleles, and these alleles originated independently of those characterized from Africa. Furthermore, this is the first report of a “hitchhiking effect” on the genetic variation around
dhps
due to selection by SP using an extensive set of microsatellite markers. Our results indicate that, in areas where there is limited gene flow, the fixation of drug-resistant parasites in the population is stable, even after drug selection is relaxed.
Dissemination of
sul3
-Containing Elements Linked to Class 1 Integrons with an Unusual 3′ Conserved Sequence Region among
Salmonella
Isolates
Authors: Antunes Patrícia , Machado Jorge , Peixe Luísa 
Published: February 2007

ABSTRACT

A
sul3
domain (IS
440
-
sul3
-
orf1
-IS
26
) was found linked to an unusual 3′ conserved sequence region (
qacH
) of class 1 integrons and detected among nontyphoid
Salmonella
isolates (
n
= 47) from different sources. Three types of integrons differing in the gene cassette array (
dfrA12
-
orfF
-
aadA2
-
cmlA1
-
aadA1
,
dfrA12
-
orfF
-
aadA2
/
1
, and
estX
-
psp
-
aadA2
-
cmlA1
-
aadA1
) were found associated with this
sul3
domain. They were associated with particular clones and specific high-molecular-weight plasmids.
Molecular Epidemiology of Macrolide and Tetracycline Resistances in Commensal
Gemella
sp. Isolates
Authors: Zolezzi Paula Cerdá , Cepero Pilar Goñi , Ruiz Joaquim , Laplana Leticia Millán , Calvo Carmen Rubio , Gómez-Lus Rafael 
Published: February 2007

ABSTRACT

The epidemiologic relatedness of 29 erythromycin-resistant
Gemella
sp. strains from normal flora, characterized previously, were evaluated by pulsed-field gel electrophoresis (PFGE). Three isolates carried the
tet
(O) gene and the
tet
(M) gene. The
msr
(A) gene was found in two
Gemella morbillorum
strains in combination with the
erm
(B) or
mef
(E) gene. The sequences of the
mef
(A/E
)
,
erm
(B), and
msr
(A) genes showed a high similarity to the corresponding sequences of other gram-positive cocci. All the strains harboring the
mef
(A/E) gene and the
msr
(D) gene possessed open reading frame 3 (ORF3)/ORF6. The 16
G. morbillorum
isolates represented 15 distinct DNA profiles. Four clusters were identified (≥80% genetic relatedness). The 12
Gemella haemolysans
strains belonged to different PFGE types. The clonal diversity found suggests that horizontal transfer may be the main route through which erythromycin resistance is acquired.