bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of TG‐43 recommended 2D‐anisotropy function for elongated brachytherapy sources
Authors: Awan Shahid B. , Meigooni Ali S. , Mokhberiosgouei Ramin , Hussain Manzoor
Published: November 2006

The original and updated protocols recommended by Task Group 43 from the American Association of Physicists in Medicine (i.e., TG‐43 and TG‐43U1, respectively), have been introduced to unify brachytherapy source dosimetry around the world. Both of these protocols are based on experiences with sources less than in length. TG‐43U1 recommends that for sources, 2D anisotropy function , should be tabulated at a minimum for radial distances of 0.5, 1.0, 2.0, 3.0, and . Anisotropy functions defined in these protocols are only valid when the point of calculation does not fall on the active length of the source. However, for elongated brachytherapy sources (active length ), some of the calculation points with active length and small may fall on the source itself and there is no clear recommendation to handle this situation. In addition, the linear interpolation technique recommended by TG‐43U1 is found to be valid for seed types of sources as the difference between for two consecutive radii is . However, in the present investigations it has been found that values of for a long source at radial distances of 2.5, 3.0, and were 2.95, 1.74, and 1.19, respectively, with differences up to about a factor of 3. Therefore, the validity of the linear interpolation technique for an elongated brachytherapy source with such a large variation in needs to be investigated. In this project, application of the TG‐43U1 formalism for dose calculation around an elongated brachytherapy source has been investigated. In addition, the linear interpolation techniques as described in TG‐43U1 for seed type sources have been evaluated for a long brachytherapy source. Application of a polynomial fit to has also been investigated as an alternate approach to the linear interpolation technique. The results of these investigations indicate that the TG‐43U1 formalism can be extended for elongated brachytherapy sources, if the two‐dimensional (2D) anisotropy function is tabulated at a minimum for radial distances of 0.2, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, , , and . Moreover, with the addition of recommended radial distances for 2D anisotropy functions, the linear interpolation technique more closely replicates Monte Carlo simulated data than a polynomial fit.
Sensitivity of linear CCD array based film scanners used for film dosimetry
Authors: Devic Slobodan , Wang Yi‐Zhen , Tomic Nada , Podgorsak Ervin B.
Published: November 2006

Film dosimetry is commonly performed by using linear CCD array transmission optical densitometers. However, these devices suffer from a variation in response along the detector array. If not properly corrected for, this nonuniformity may lead to significant overestimations of the measured dose as one approaches regions close to the edges of the scanning region. In this note, we present measurements of the spatial response of an AGFA Arcus II document scanner used for radiochromic film dosimetry. Results and methods presented in this work can be generalized to other CCD based transmission scanners used for film dosimetry employing either radiochromic or radiographic films.
A quality assurance program for the on‐board
Authors: Yoo Sua , Kim Gwe‐Ya , Hammoud Rabih , Elder Eric , Pawlicki Todd , Guan Huaiqun , Fox Timothy , Luxton Gary , Yin Fang‐Fang , Munro Peter
Published: November 2006

To develop a quality assurance (QA) program for the On‐Board Imager (OBI) system and to summarize the results of these QA tests over extended periods from multiple institutions. Both the radiographic and cone‐beam computed tomography (CBCT) mode of operation have been evaluated. The QA programs from four institutions have been combined to generate a series of tests for evaluating the performance of the On‐Board Imager. The combined QA program consists of three parts: (1) safety and functionality, (2) geometry, and (3) image quality. Safety and functionality tests evaluate the functionality of safety features and the clinical operation of the entire system during the tube warm‐up. Geometry QA verifies the geometric accuracy and stability of the OBI/CBCT hardware/software. Image quality QA monitors spatial resolution and contrast sensitivity of the radiographic images. Image quality QA for CBCT includes tests for Hounsfield Unit (HU) linearity, HU uniformity, spatial linearity, and scan slice geometry, in addition. All safety and functionality tests passed on a daily basis. The average accuracy of the OBI isocenter was better than with a range of variation of less than over 8 months. The average accuracy of arm positions in the mechanical geometry QA was better than , with a range of variation of less than over 8 months. Measurements of other geometry QA tests showed stable results within tolerance throughout the test periods. Radiographic contrast sensitivity ranged between 2.2% and 3.2% and spatial resolution ranged between 1.25 and . Over four months the CBCT images showed stable spatial linearity, scan slice geometry, contrast resolution (1%; disk) and spatial resolution . The HU linearity was within for all measurements. By combining test methods from multiple institutions, we have developed a comprehensive, yet practical, set of QA tests for the OBI system. Use of the tests over extended periods show that the OBI system has reliable mechanical accuracy and stable image quality. Nevertheless, the tests have been useful in detecting performance deficits in the OBI system that needed recalibration. It is important that all tests are performed on a regular basis.
Clinical use of EBT model Gafchromic™ film in radiotherapy
Authors: Fiandra Christian , Ricardi Umberto , Ragona Riccardo , Anglesio Silvia , Romana Giglioli Francesca , Calamia Elisa , Lucio Francesco
Published: November 2006

The Gafchromic™ EBT was recently introduced in film dosimetry for external beam therapy (EBT). The high spatial resolution, weak energy dependence, and near‐tissue equivalence of EBT films make them suitable for measurement of dose distributions in radiotherapy, especially intensity‐modulated radiation therapy (IMRT). Starting with a sensitometric curve and dose uncertainty relative to the flatbed scanner, the goal of this study was to find an efficient method of correcting for light scattering, and to compare dose distribution supplied by Gafchromic™ EBT with the distribution obtained with a 2D ion‐chamber detector system. Light scattering was analyzed for different levels of dose, and was found to depend on the red‐scale value as well as the position of the pixel on the scanner. Many “uniform” films were exposed at different levels of dose to create a two‐dimensional matrix correction to take this effect into account. The dose distribution obtained for three clinical beams (, open fields and wedge field) were in agreement with those supplied by the 2D array. Gamma index (using distance and 5% dose as constraints) for the three fields considered was reached in an average of 98% of the points.
Genetic Diversity of Norovirus among Children with Gastroenteritis in São Paulo State, Brazil
Authors: Castilho Juliana Galera , Munford Veridiana , Resque Hugo Reis , Fagundes-Neto Ulysses , Vinjé Jan , Rácz Maria Lúcia
Published: November 2006

Norovirus (NoV) is one of the most common causes of acute gastroenteritis in children and adults. To study the prevalence and genetic variability of NoV in children with acute gastroenteritis in São Paulo State, Brazil, we examined 234 stool samples from children with or without gastroenteritis during a 5-year period (1995 to 1999). NoV RNA was detected by reverse transcription-PCR and confirmed by DNA sequence analysis. We used two different oligonucleotide primer sets targeting the 3′ end of the RNA polymerase gene (region B), as well a partial capsid region at the 3′ end of the VP1 gene (region D). A total of 78 (33.3%) of the samples tested positive for NoV, and in region B, of the 66 strains sequenced, 4 (6.1%) belonged to GI, 52 (78.7%) belonged to GII, and five samples (7.6%) contained a mixture of the GI and GII genotypes. Phylogenetic analysis showed that the majority (40 of 66 [60.6%]) of the strains belonged to genotype GII.4. The nucleotide sequence identity of three strains was lower than 77.9% compared to a region B reference sequence database but showed 85.3 to 88.8% identity with GII.2 Melksham strain in region D, indicating the circulation of a possible recombinant NoV strain. One sample (GII.3) was sequenced only in region D. In conclusion, we have a total of 67 sequenced strains. This is the first report that describes the predominance of GII.4 NoV strains in children visiting the ambulatory of different hospitals in São Paulo State, Brazil, and we show that mixtures of different strains can be found in individual samples, including some possible new recombinant strains.
Detection of
Aspergillus
DNA in Cerebrospinal Fluid from Patients with Cerebral Aspergillosis by a Nested PCR Assay
Authors: Hummel M. , Spiess B. , Kentouche K. , Niggemann S. , Böhm C. , Reuter S. , Kiehl M. , Mörz H. , Hehlmann R. , Buchheidt D.
Published: November 2006

Invasive aspergillosis (IA), a complication with high mortality rates, especially in disseminated IA with cerebral involvement, is difficult to diagnose. Biopsy of cerebral lesions is often not feasible, and culture of
Aspergillus
spp. from cerebrospinal fluid (CSF) is frequently negative. New molecular methods have emerged for diagnosing IA. So far, there are only few reports of
Aspergillus
DNA detection in CSF. After modifying the DNA extraction protocol, we detected
Aspergillus
DNA in CSF samples by a previously described nested PCR assay. In six patients with hematologic malignancy and cerebral aspergillosis, CSF samples were investigated for
Aspergillus
DNA. IA was classified according to the EORTC/MSG 2002 criteria. Two patients each had proven, probable, and possible IA. Thirty-five CSF samples were investigated for
Aspergillus
DNA by nested PCR. Samples with positive results in the nested PCR assay were quantified by LightCycler PCR assay. Fourteen CSF samples showed positive results in the nested PCR assay. Of these, six samples gave positive results in real-time PCR. The range of CFU per ml was 2,154 to 63,100,000. The highest number of CFU per ml was found in a CSF sample of a patient with acute lymphocytic leukemia and probable cerebral aspergillosis. Detection of
Aspergillus
DNA in CSF samples is thus possible and has the potential to improve diagnosis of cerebral aspergillosis. Further prospective studies with larger numbers of patients must be performed to evaluate the clinical significance of
Aspergillus
PCR with CSF samples.
Crimean-Congo Hemorrhagic Fever Virus: Genetic Analysis and Tick Survey in Turkey
Authors: Tonbak Sukru , Aktas Munir , Altay Kursat , Azkur Ahmet K. , Kalkan Ahmet , Bolat Yusuf , Dumanli Nazir , Ozdarendeli Aykut
Published: November 2006

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus in the family
Bunyaviridae
, genus
Nairovirus
. The virus is transmitted to humans through infected tick bites or from direct contact with viremic animals or humans. In the present study, a total of 1,015 adult ticks were collected from cattle (603 specimens), sheep (17 specimens), and goats (395 specimens) in the Kelkit Valley in Turkey. Four tick species were recognized on the animals in the surveyed region. The most abundant species were
Rhipicephalus bursa
and
Hyalomma marginatum marginatum
, at 47.68% (484/1,015) and 46.40% (471/1,015), respectively. Reverse transcriptase PCR was used to recover partial sequences of the CCHFV small (S) genome segment. The presence of CCHFV was determined in 3 of 33 (9.09%)
R. bursa
pools and in 1 of 31 (3.22%)
H. m. marginatum
pools. Virus sequences from
R. bursa
were extremely different from those of the Greek CCHFV strain (U04958) isolated from an
R. bursa
tick. Phylogenetic analysis indicated that the CCHFV isolates obtained in this study clustered in group 5, whose range encompasses southwestern Russian and Kosovo. This is the first evidence of CCHFV in ticks from Turkey. Even though
Hyalomma
is the main vector for CCHFV,
R. bursa
may play a role in CCHFV transmission.
Outbreak of Infection by Carbapenem-Resistant
Acinetobacter baumannii
Producing the Carbapenemase OXA-58 in Belgium
Authors: Bogaerts Pierre , Naas Thierry , Wybo Ingrid , Bauraing Caroline , Soetens Oriane , Piérard Denis , Nordmann Patrice , Glupczynski Youri
Published: November 2006

Carbapenem-resistant
Acinetobacter baumannii
isolates were obtained from 17 patients between September 2004 and August 2005 at the Academisch Ziekenhuis Vrije Universiteit Brussel, Brussels, Belgium. These multidrug-resistant isolates, which belonged to a single clone, remained susceptible to colistin and tigecycline only and produced the carbapenem-hydrolyzing oxacillinase OXA-58. This study highlights the importance of the intercountry spread of this β-lactamase-mediated resistance mechanism and its epidemic evolution.
Molecular Characterization of Disease-Associated Streptococci of the Mitis Group That Are Optochin Susceptible
Authors: Balsalobre Luz , Hernández-Madrid Antonia , Llull Daniel , Martín-Galiano Antonio J. , García Ernesto , Fenoll Asunción , de la Campa Adela G.
Published: November 2006

Eight optochin-susceptible (Opt
s
) alpha-hemolytic (viridans) streptococcus isolates were characterized at the molecular level. These isolates showed phenotypic characteristics typical of both viridans streptococci and
Streptococcus pneumoniae
. Comparison of the sequence of housekeeping genes from these isolates with those of
S. pneumoniae
,
Streptococcus mitis
,
Streptococcus oralis
, and
Streptococcus pseudopneumoniae
suggested that the Opt
s
isolates corresponded to streptococci of the mitis group. Besides, the Opt
s
streptococci were negative by a Gen-Probe AccuProbe pneumococcus test and hybridized with specific pneumococcal probes (
lytA
and
ply
) but also with
ant
, a gene not present in most
S. pneumoniae
strains. Moreover, the isolates were insoluble in 1% sodium deoxycholate but completely dissolved in 0.1% deoxycholate. Sequence analysis of the
lytA
gene revealed that the Opt
s
streptococci carried
lytA
alleles characteristic of those present in nonpneumococcal streptococci of the mitis group. The determination of the partial nucleotide sequence embracing the
atp
operon encoding the F
o
F
1
H
+
-ATPase indicated that the optochin susceptibility of the isolates was due to the acquisition of
atpC
,
atpA
, and part of
atpB
from
S. pneumoniae
by horizontal gene transfer.
Mixed Pulmonary Infection with
Strongyloides stercoralis
and
Blastomyces dermatitidis
Authors: Sciortino Carmen , Omar Rawhi , De La Cruz Rafael
Published: November 2006

We report the first case of mixed pulmonary infection with
Strongyloides stercoralis
and
Blastomyces dermatitidis
. Histopathology from the lung biopsy showed structures consistent with
B. dermatitidis
and
S. stercoralis
. A parasitology exam from a bronchi alveolar lavage yielded an immature rhabditiform larva and female worm. Fungal cultures grew
B. dermatitidis
.
Molecular Analysis of Clinical Isolates of
Mycobacterium bovis
Recovered from Humans in Italy
Authors: Lari Nicoletta , Rindi Laura , Bonanni Daniela , Tortoli Enrico , Garzelli Carlo
Published: November 2006

In order to achieve a better knowledge of
Mycobacterium bovis
epidemiology in Italy, 42 clinical isolates from humans were genotyped. Predominant molecular patterns were found in one cluster of 15 isolates sharing spoligotype (ST482), variable-number tandem repeat (VNTR), and IS
6110
-based restriction fragment length polymorphism (one 1.9-kb band) profiles and in two clusters of 6 and 3
Mycobacterium bovis
BCG isolates differing by one VNTR character. The remaining 18 isolates yielded unique profiles. Our results confirm the potential utility of spoligotyping and VNTR typing as a major typing system of
M. bovis
isolates.
Multiplex Real-Time Reverse Transcription-PCR Assay for Determination of Hepatitis C Virus Genotypes
Authors: Cook Linda , Sullivan KaWing , Krantz Elizabeth M. , Bagabag Arthur , Jerome Keith R.
Published: November 2006

A variety of methods have been used to determine hepatitis C virus (HCV) genotypes. Because therapeutic decisions for chronic HCV-related hepatitis are made on the basis of genotype, it is important that genotype be accurately determined by clinical laboratories. Existing methods are often subjective, inaccurate, manual, time-consuming, and contamination prone. We therefore evaluated real-time reverse transcription-PCR (RT-PCR) reagents that have recently become commercially available (Abbott HCV Genotype ASR). The assay developed by our laboratory starts with purified RNA and can be performed in 4 to 5 h. An initial evaluation of 479 samples was done with a restriction fragment length polymorphism (RFLP) method and the RT-PCR assay, and discrepant samples were sequenced. An additional 1,200 samples were then tested, and data from all assays were used to evaluate the efficiency and specificity of each genotype-specific reaction. Good correlation between results by the two methods was seen. Discrepant samples included those indeterminate by the RT-PCR assay (
n
= 110) and a subset that were incorrectly called 2a by the RFLP method (
n
= 75). The real-time RT-PCR assay performed well with genotype 1, 2, and 3 samples. Inadequate numbers of samples were available to evaluate fully genotypes 4, 5, and 6. Analysis of each primer-probe set demonstrated that weak cross-reactive amplifications were common but usually did not interfere with the genotype determination. However, in about 1% of samples, two or more genotypes amplified at roughly equivalent amounts. Further studies are necessary to determine whether these mixed-genotype samples are true mixtures or a reflection of occasional cross-reactive amplifications.
Pilot Study of a Commercialized Human Papillomavirus (HPV) Genotyping Assay: Comparison of HPV Risk Group to Cytology and Histology
Authors: Castle Philip E. , Sadorra Mark , Garcia Francisco , Holladay E. Blair , Kornegay Janet
Published: November 2006

We evaluated a commercialized PCR assay, Linear Array, that detects 37 human papillomavirus (HPV) genotypes, using a sample of liquid cytology specimens (
n
= 534). We found a strong association of an increasing level of HPV risk (HPV type 16 [HPV16] > HPV18 > other carcinogenic types > noncarcinogenic types > negative specimens) with increasing severities of cytologic interpretations (
P
Trend
< 0.0005) and histologic diagnoses (
P
Trend
< 0.0005).
PERIODIC AHARONOV–BOHM SOLENOIDS IN A CONSTANT MAGNETIC FIELD
Authors: MINE TAKUYA , NOMURA YUJI
Published: November 2006

We consider the magnetic Schrödinger operator on R2. The magnetic field is the sum of a homogeneous magnetic field and periodically varying pointlike magnetic fields on a lattice. We shall give a sufficient condition for each Landau level to be an infinitely degenerated eigenvalue. This condition is also necessary for the lowest Landau level. In the threshold case, we see that the spectrum near the lowest Landau level is purely absolutely continuous. Moreover, we shall give an estimate for the density of states for Landau levels and their gaps. The proof is based on the method of Geyler and Šťovíček, the magnetic Bloch theory, and canonical commutation relations.
PHASE TRANSITION IN THE HIGGS MODEL OF SCALAR DYONS
Authors: DAS C. R. , LAPERASHVILI L. V.
Published: November 2006

In this paper we investigate the phase transition "Coulomb-confinement" in the Higgs model of Abelian scalar dyons – particles having both, electric e and magnetic g, charges. It is shown that by dual symmetry this theory is equivalent to scalar fields with the effective squared electric charge e*2 = e2+g2. But the Dirac relation distinguishes the electric and magnetic charges of dyons. The following phase transition couplings are obtained in the one-loop approximation: [Formula: see text], [Formula: see text] and [Formula: see text].
EQUATION-OF-MOTION APPROACH TO DYNAMICAL MEAN FIELD THEORY
Authors: ZHU JIAN-XIN , ALBERS R. C. , WILLS J. M.
Published: November 2006

We propose using an equation-of-motion approach as an impurity solver for dynamical mean field theory. As an illustration of this technique, we consider a finite-U Hubbard model defined on the Bethe lattice with infinite connectivity at arbitrary filling. Depending on the filling, the spectra that is obtained exhibits a quasiparticle peak, and lower and upper Hubbard bands as typical features of strongly correlated materials. The results are also compared and in good agreement with exact diagonalization. We also find a different picture of the spectral weight transfer than the iterative perturbation theory.
THE INFLUENCE OF CARBON AND BORON ATOMS ON THE OPTICAL AND ELECTRICAL PROPERTIES OF THIN FILM a-Si:H
Authors: KARABAY ISIK
Published: November 2006

A series of undoped and p-doped a-SiC:H samples have been made in the framework of a research plan for obtaining high quality p-type window layers by "Plasma Enhanced Chemical Vapor Deposition (PECVD)" technique from the mixtures of silane ( SiH 4), methane ( CH 4) and diborane ( B 2 H 6) gases. For the optimization of the window layer, the dependence of the electrical (conductivity) and optical (band gap) properties due to altered ratios of methane and diborane gases were investigated. When the diborane gas ratio was changed from Y = 0.06 to Y = 0.24 with an increase of 0.06 steps at a constant of X = 0.948 methane gas ratio, the dark conductivity and optical band gap values changed from ~ 10-19 (Ω· cm )-1 to ~ 10-10 (Ω· cm )-1 and 2.542 eV to 2.178 eV, respectively, and between these values, the most appropriate layers can be selected.
Closed conformal vector fields on pseudo‐Riemannian manifolds
Authors: Catalano D. A.
Published: November 2006

We give here a geometric proof of the existence of certain local coordinates on a pseudo‐Riemannian manifold admitting a closed conformal vector field.
One‐pile misère Nim for three or more players
Authors: Kelly Annela R.
Published: November 2006

The analysis of the classical game of Nim relies on binary
representation of numbers as shown in the books of Berlekamp and
Gardener. There is considerable interest in generalizations and
modifications of the game. We will consider one‐pile misère Nim
for more than two players. In the case of three or more players,
the impartial game theory results rarely apply. In this note, we
analyze the game in a variety of cases where alliances are formed
among the players.
Tauberian‐type theorems with application to the Stieltjes transformation
Authors: Gaikwad S. B. , Chaudhary M. S.
Published: November 2006

In the first part, we define the space L′(r) and the modified Stieltjes transformation introduced by Lavoine and Misra (1979) and Marichev (1983), respectively. In the second part of the paper, we extend Tauberian‐type theorems for the distributional Stieltjes transformations to the distributional modified Stieltjes transformations.
A note on comprehensive backward biorthogonalization
Authors: Ruch David K.
Published: November 2006

We present a backward biorthogonalization technique for giving an orthogonal projection of a biorthogonal expansion onto a smaller subspace, reducing the dimension of the initial space by dropping d basis functions. We also determine which basis functions should be dropped to minimize the L2 distance between
a given function and its projection. This generalizes some results in [3].
Analysis and Application of Sheppard’s Airflow Model to Predict Mechanical Orographic Lifting and the Occurrence of Mountain Clouds
Authors: Kleissl Jan , Honrath Richard E. , Henriques Diamantino V.
Published: November 2006

Mechanically driven orographic lifting is important for air pollution dispersion and weather prediction, but the small dimensions of mountain peaks often prevent numerical weather models from producing detailed forecasts. Mechanical lifting in stratified flow over mountains and associated thermodynamic processes were quantified and evaluated using Sheppard’s model to estimate the dividing-streamline height zt. The model was based on numerical weather model profile data and was evaluated using ground-based measurements on a tall, axisymmetric mountaintop for which the nondimensional mountain height hND = hN/U∞ is frequently between 1 and 10 (here h is mountain height, N is Brunt–Väisälä frequency, and U∞ is upstream horizontal wind speed). Sheppard’s formula was successful in predicting water vapor saturation at the mountaintop, with a false-prediction rate of 14.5%. Wind speed was found to be strongly related to the likelihood of forecast errors, and wind direction, season, and stratification did not play significant roles. The potential temperature (water vapor mixing ratio) at zt in the sounding was found to be slightly smaller (larger) than at the mountaintop, on average, indicating less lifting than predicted and/or turbulent mixing with higher-altitude air during parcel ascent. Detailed analysis revealed that this difference is a result of less lifting than predicted for small U∞/(Nh), whereas Sheppard’s model predicts the relative increase in uplift with increasing U∞/(Nh) correctly for U∞/(Nh) > 0.2.
Indication of Successful Crystallization of Dry Gel into *BEA-type Zeolite
Authors: Inagaki Satoshi , Nakatsuyama Kei , Saka Yuji , Kikuchi Eiichi , Kohara Shinji , Matsukata Masahiko
Published: November 2006

Tetraethylammonium (TEA+)-containing silicate dry gels exhibiting a maximum in the reflection peak at 2θ = 28° in an XRD pattern using Cu Kα radiation are always transformed into *BEA-type zeolite with steam-assisted crystallization.
On “Intention” in the Definition of Suicide
Authors: Andriessen Karl
Published: November 2006

The need for a comprehensive nomenclature in suicidology is now well recognized. In this paper the focus is on the issue of intention, which is identified as an essential aspect of any definition of suicide and suicidal behavior primarily because of its distinction from accidental behavior. The distinction between the retrospective perspective of motives versus the prospective perspective of intentions is highlighted, and I argue that the latter is more closely related to suicidal behavior. Finally, while motives and intentions tend to be used together in research, there is a need for sound research to clarify the roles of intentions in order to better understand suicide and attempted suicide.
Insulin regulation of gene expression and concentrations of white adipose tissue-derived proteins in vivo in healthy men: relation to adiponutrin
Authors: Faraj May , Beauregard Genevieve , Loizon Emmanuelle , Moldes Marthe , Clément Karine , Tahiri Youssef , Cianflone Katherine , Vidal Hubert , Rabasa-Lhoret Rémi
Published: November 2006

Adiponutrin is a newly described white adipose tissue (WAT)-derived protein whose function and regulation remain widely unclear in humans though it is suggested to be related to insulin sensitivity. Recently, we found that adiponutrin expression is reduced in type 2 diabetic subjects in basal and insulin-stimulated states. To examine adiponutrin regulation by the insulin pathway in relation to other WAT-related proteins with well-known relation to insulin signaling and action, we examined in healthy young men (1) the association of adiponutrin with p85α PI3K and HKII, leptin, adiponectin, and acylation-stimulating protein (ASP) and (2) the regulation of adiponutrin and WAT-derived proteins by 3-h hyperinsulinemic euglycemic clamp (HIEG). At baseline (N = 20), adiponutrin expressions were positively correlated with those of p85α PI3K (R = 0.54, P = 0.017), HKII (R = 0.58, P = 0.010), and serum leptin (R = 0.51, P = 0.036), but not with any other parameter measured including insulin sensitivity. Hyperinsulinemia (N = 10, +2365% above baseline) significantly increased the expression of adiponutrin (+770%, P = 0.002), p85α PI3K (+150%, P = 0.033), HKII (+147%, P = 0.007), and serum leptin (+11%, P = 0.031), while it decreased serum adiponectin (−15%, P = 0.001). In the insulin-stimulated state, adiponutrin mRNA expression levels correlated with basal p85α PI3K (R = 0.76, P = 0.018) and HKII (R = 0.86, P = 0.003) expression levels, with percentage increase in insulin (R = 0.73, P = 0.040), and with insulin-stimulated state HKII (R = 0.82, P = 0.007), leptin (R = 0.84, P = 0.005), and adiponectin (R = 0.85, P = 0.004) mRNA levels. In healthy young men, adiponutrin expression is unregulated by hyperinsulinemia and is related to basal and/or insulin-stimulated p85α PI3K, HKII, adiponectin, and leptin expression levels. We hypothesize that insulin-mediated regulation of adiponutrin expression is under the PI3K pathway. The relevance of the present findings to reduced adiponutrin expression in type 2 diabetes is discussed.
Peptide YY (PYY)3–36 modulates thyrotropin secretion in rats
Authors: Oliveira K J , Paula G S M , Costa-e-Sousa R H , Souza L L , Moraes D C , Curty F H , Pazos-Moura C C
Published: November 2006

Peptide YY (PYY)3-36 is a gut-derived hormone, with a proposed role in central mediation of postprandial satiety signals, as well as in long-term energy balance. In addition, recently, the ability of the hormone to regulate gonadotropin secretion, acting at pituitary and at hypothalamus has been reported. Here, we examined PYY3-36 effects on thyrotropin (TSH) secretion, both in vitro and in vivo. PYY3-36-incubated rat pituitary glands showed a dose-dependent decrease in TSH release, with 44 and 62% reduction at 10−8 and 10−6 M (P < 0.05 and P < 0.001 respectively), and no alteration in TSH response to thyrotropin-releasing hormone. In vivo, PYY3-36 i.p. single injection in the doses of 3 or 30 cg/kg body weight, administered to rats fed ad libitum, was not able to change serum TSH after 15 or 30 min. However, in fasted rats, PYY3-36 at both doses elicited a significant rise (approximately twofold increase, P < 0.05) in serum TSH observed 15 min after the hormone injection. PYY3-36 treatment did not modify significantly serum T4, T3, or leptin. Therefore, in the present paper, we have demonstrated that the gut hormone PYY3-36 acts directly on the pituitary gland to inhibit TSH release, and in the fasting situation, in vivo, when serum PYY3-36 is reduced, the activity of thyroid axis is reduced as well. In such a situation, systemically injected PYY3-36 was able to acutely activate the thyrotrope axis, suggesting a new role for PYY3-36 as a regulator of the hypothalamic–pituitary–thyroid axis.
Solid Phase Extraction and Spectrophotometric Determination of Trace Amounts of Thiocyanate in Real Samples
Authors: Ghaedi Mehrorang , Parham Hooshang , Moghadam Majid , Mortazavi Kianosh , Soylak Mustafa
Published: November 2006

A simple, selective and rapid method for solid phase extraction and spectrophotometric determination of thiocyanate using a manganese (III) tetrakis (p‐sulfonatophenyl) porphyrin, [Mn (TPPS) OAC] bound to Amberlite IR‐400 has been developed. The influence of pH, amount of solid phase, sample matrix, type and amount of eluting agent and flow rates i.e. variables affecting the efficiency of the extraction system were evaluated and conditions of the sample, eluting solution and active phase were optimized. The maximal capacity was found to be as 1.16 μg mL‐1 for 1200 mL. Thiocyanate ions can be eluted quantitatively with 8 mL 0.3 M ferric chloride. The enrichment factor was 150. The linear range of the determination is between 0.4‐2.0 μg mL‐1 for preconcentration method with a limit of detection of 2.8 ng mL‐1. The method has been successfully applied for determination of trace amounts of thiocyanate in tap water, saliva sample and a synthetic mixture.
Investigation of turbulence characteristics in a gas cyclone by stereoscopic PIV
Authors: Liu Zhengliang , Jiao Jinyu , Zheng Ying , Zhang Qikai , Jia Lufei
Published: November 2006

Stereoscopic particle image velocimetry (Stereo‐PIV) was used as the tool to observe the turbulence characteristics in a gas cyclone. In the cylindrical and conical parts of the cyclone, intensive fluctuation occurs in the inner quasi‐forced vortex, especially in its core where the precessing vortex core dominates. In the dust hopper, strong turbulence is observed at the interface between the downward flow and the upward flow, as well as in the centerline of the cyclone. Turbulence intensity in the tangential, axial, and radial directions and the Reynolds stresses are seen to be anisotropic: this anisotropy provides the evidence of more appropriateness of the Reynolds stress model (RSM) than the standard k‐ε model, and the renormalization‐group k‐ε model for numerical simulations in gas cyclones. Due to flow instability and back‐mixing caused by the turbulence, separated particles could disperse into and be re‐entrained by the upward flow from the bin to degrade the separation efficiency of the cyclone. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Fluorescence resonance energy transfer between two quantum dots with immunocomplexes of antigen and antibody as a bridge
Authors: Li Yabing , Ma Qiang , Wang Xinyan , Su Xingguang
Published: November 2006

In this study, 573 nm quantum dots (QDs)‐rabbit IgG–goat anti‐rabbit IgG–638 nm QDs immunocomplexes were prepared, utilizing antigen–antibody interaction. 573 nm‐emitting QDs were conjugated to antigen (rabbit IgG) and 638 nm‐emitting QDs were conjugated to antibody (goat anti‐rabbit IgG) via electrostatic/hydrophilic self‐assembly, respectively. The mutual affinity of the antigen and antibody brought two kinds of QDs close enough to result in fluorescence resonance energy transfer (FRET) between them; the luminescence emission of 573 nm QDs was quenched, while that of 638 nm QDs was enhanced. The luminescence emission of 573 nm QDs could be recovered when the immunocomplexes were exposed to the unlabelled rabbit IgG antigen. The FRET efficiency (E) and the distance between the donor and the acceptor were calculated. Copyright © 2006 John Wiley & Sons, Ltd.
Singlet oxygen generation from lophine hydroperoxides
Authors: Kimura M. , Lu G. H. , Nishigawa H. , Zhang Z. Q. , Hu Z. Z.
Published: November 2006

Singlet oxygen was detected from the reaction of lophine hydroperoxides 2 in the presence of 1,3‐diphenyl‐isobenzofuran as a singlet oxygen detector. In order to examine the substituent effect on the formation of 1O2, 2‐(p‐substituted phenyl) lophine peroxides 2a–c were tested. It was found that an electron‐attracting group contributed to the efficient formation of 1O2 (80% for a NO2 group), while an electron‐donating group enhanced the efficiency of chemiluminescence. Copyright © 2006 John Wiley & Sons, Ltd.
Sequence‐specific purification of DNA oligomers in hydrophobic interaction chromatography using peptide nucleic acid amphiphiles: Extended dynamic range
Authors: Savard Jeffrey M. , Schneider James W.
Published: November 2006

We present improvements on a previously reported method (Vernille JP, Schneider JW. 2004. Biotechnol Prog 20(6):1776–1782) to purify DNA oligomers by attachment of peptide nucleic acid amphiphiles (PNAA) to particular sequences on the oligomers, followed by their separation from unbound oligomers using hydrophobic interaction chromatography (HIC). Use of alkyl‐modified HIC media (butyl and octyl sepharose) over phenyl‐modified media (phenyl sepharose) reduced the elution time of unbound DNA while not affecting the elution time of the PNAA/DNA complex. Modifying the alkane tail length for PNAA from C12 to C18 increased slightly the retention of PNAA/DNA duplexes. By combining these two refinements, we show that sequence‐specific purifications of DNA oligomers 60 bases in length or more can be achieved with high resolution, even when the PNAA alkane is attached to the center of the target strand. The insensitivity of the PNAA/DNA duplex binding to choice of HIC media appears to be due to a surface‐induced aggregation phenomenon that does not occur in the case of untagged DNA. We also report on the use of batch HIC as an adequate predictor of elution profiles in linear gradient HIC, and its potential to considerably reduce purification times by applying step gradients. Biotechnol. Bioeng. 2007;97: 367–376. © 2006 Wiley Periodicals, Inc.
Fusion to a pull‐down domain: a novel approach of producing Trigonopsis variabilisD‐amino acid oxidase as insoluble enzyme aggregates
Authors: Nahalka Jozef , Nidetzky Bernd
Published: November 2006

Insoluble protein particles showing high specific enzyme activity are potentially useful biocatalysts. The commercialized crosslinked enzyme crystals and aggregates have the disadvantage that their preparation requires isolation of the protein before the critical precipitation step. We introduce a novel concept of controlled precipitation in vivo in which the target enzyme is fused to the cellulose‐binding domain (CBD) of Clostridium cellulovorans, and expression in Escherichia coli is performed under conditions that induce selective pull down of the folded chimeric protein via intermolecular self‐aggregation of the CBD. The case of D‐amino acid oxidase from Trigonopsis variabilis shows that upon fusion of the CBD to its N‐terminus, the otherwise mainly soluble recombinant enzyme was quantitatively precipitated in protein particles, which displayed 40% of the specific activity of the highly purified oxidase. By contrast, inclusion bodies derived from an enzyme chimera, which harbored a C‐terminal peptide tag, showed only little oxidase activity (≤ 10%). The aggregated CBD retained the ability to bind microcrystalline cellulose and flocculated polysaccharide particles upon attachment to them. The cellulose‐bound oxidase was stabilized about 36 times against inactivation of the soluble enzyme during conversion of D‐methionine and bubble aeration. Biotechnol. Bioeng. 2007;97: 454–461. © 2006 Wiley Periodicals, Inc.
Regulation of Exocytosis in Chromaffin Cells by Trans‐Insertion of Lysophosphatidylcholine and Arachidonic Acid into the Outer Leaflet of the Cell Membrane
Authors: Amatore Christian , Arbault Stéphane , Bouret Yann , Guille Manon , Lemaître Frédéric , Verchier Yann
Published: November 2006

Vesicular exocytosis is an important complex process in the communication between cells in organisms. It controls the release of chemical and biochemical messengers stored in an emitting cell. In this report, exocytosis is studied amperometrically (at carbon fiber ultramicroelectrodes) at adrenal chromaffin cells, which release catecholamines after appropriate stimulation, while testing the effects due to trans‐insertion of two exogenous compounds (lysophosphatidylcholine (LPC) and arachidonic acid (AA)) on the kinetics of exocytotic events. Amperometric analyses showed that, under the present conditions (short incubation times and micromolar LPC or AA solutions), LPC favors catecholamine release (rate, event frequency, charge released) while AA disfavors the exocytotic processes. The observed kinetic features are rationalized quantitatively by considering a stalk model, for the fusion pore formation, and the physical constraints applied to the cell membrane by the presence of small fractions of LPC and AA diluted in its external leaflet (trans‐insertion). We also observed that the detected amount of neurotransmitters in the presence of LPC was larger than under control conditions, while the opposite trend is observed with AA.
Exploring the Dynamics of Calix[4]pyrrole: Effect of Solvent and Fluorine Substitution
Authors: Blas J. Ramón , López‐Bes Jose Maria , Márquez Manuel , Sessler Jonathan L. , Luque F. Javier , Orozco Modesto
Published: November 2006

Molecular dynamics simulations show that calix[4]pyrrole (CP) and octafluorocalix[4]pyrrole (8F‐CP) are extremely flexible molecules. CP mainly adopts the 1,3‐alternate conformation in all the solvents, although the percentage of alternative conformations increases in polar solvents, especially those with good hydrogen‐bonding acceptor properties. However, in the case of 8F‐CP, the cone conformation is the most populated in some solvents. Transitions between conformers are common and fast, and both CP and 8F‐CP can adopt the cone conformation needed for optimum interaction with anions more easily than would be predicted on the basis of previous gas‐phase calculations. Furthermore, the present studies show that when a fluoride anion is specifically placed initially in close proximity to CP and 8F‐CP in their respective 1,3‐alternate conformations, an extremely fast change to the cone conformation is observed in both cases. The results suggest that preorganization does not represent a major impediment to anion‐binding for either CP or 8F‐CP, and that ion‐induced conformational changes can follow different mechanisms depending on the solvent and the chemical substituents present on the calix[4]pyrrole beta‐pyrrolic positions.
Design, Synthesis, and Delivery Properties of Novel Guanidine‐Containing Molecular Transporters Built on Dimeric Inositol Scaffolds
Authors: Maiti Kaustabh K. , Jeon Ock‐Youm , Lee Woo Sirl , Chung Sung‐Kee
Published: November 2006

We have developed a novel class of synthetic molecular transporters that contain eight residues of guanidine with an inositol dimer as the scaffold. The dimers were prepared by connecting two units ofmyo‐ orscyllo‐inositol via a carbonate or amide linkage, and the multiple units of the guanidine functionality were constructed on the inositol scaffold by means of peracylation with ω‐aminocarboxylate derivatives of varying length. Bioassays based on confocal laser scanning microscopy and fluorescence‐activated cell sorter analyses indicated that these transporters display a varying degree of membrane translocating ability, and the intracellular localization and mouse‐tissue distribution studies strongly suggested that these transporters undergo substantially different mechanistic processes from those of peptide transporters reported to date. It was also shown that doxorubicin, an anticancer antibiotic, can be efficiently delivered into mouse brain by aid of this type of transporter.
Glycosidation–Anomerisation Reactions of 6,1‐Anhydroglucopyranuronic Acid and Anomerisation of β‐D‐Glucopyranosiduronic Acids Promoted by SnCl4
Authors: O'Brien Colin , Poláková Monika , Pitt Nigel , Tosin Manuela , Murphy Paul V.
Published: November 2006

The reaction of silylated nucleophiles with 6,1‐anhydroglucopyranuronic acid (glucuronic acid 6,1‐lactones) catalysed by tin(IV) chloride provides 1,2‐trans or 1,2‐cis (deoxy)glycosides in a manner dependent on the donor structure. The α‐glycoside was obtained for reactions of the donor with the 2‐acyl group and 2‐deoxydonors, whereas the 2‐deoxy‐2‐iodo donor gave the β‐glycoside. Experimental evidence shows that when 1,2‐cis‐glycoside formation occurs, the anomerisation of initially formed 1,2‐trans‐glycosides catalysed by SnCl4 is possible. The anomerisation of β‐D‐glucopyranosiduronic acids was found to be faster, in some cases, than anomerisation of related β‐D‐glucopyranosiduronic acid esters and β‐D‐glucopyranoside derivatives and the rates are dependent on the structure of the aglycon. Moreover, the rates of anomerisation of β‐D‐glucopyranuronic acid derivatives can be qualitatively correlated with rates of hydrolysis of β‐D‐glucopyranosiduronic acids. Mechanistic possibilities for the reactions are considered.
Density functional theory calculations of optical rotation: Employment of ADZP and its comparison with other basis sets
Authors: Neto Antônio Canal , Jorge Francisco E.
Published: November 2006

Density function theory calculations of frequency dependent optical rotations ([α]ω) for 30 rigid chiral molecules are reported. Calculations have been carried out at the sodium D line frequency, using the augmented double zeta valence quality plus polarization functions (ADZP) basis set and the BP86 nonhybrid and B3LYP hybrid functionals. Gauge‐invariant atomic orbitals were used to guarantee origin‐independent values of [α]D. Comparison between corresponding results obtained with nonhybrid and hybrid functionals as well as with theoretical optical rotations reported in the literature is done. Excited electronic states of three molecules are also discussed in light of circular dichroism spectra and B3LYP and BP86 calculated excitation energies and rotatory strengths. One verifies that the B3LYP/ADZP results are in better agreement with experiment. Chirality, 2006. © 2006 Wiley‐Liss, Inc.
Direct Experimental Observation of CS2OH
Authors: de Petris Giulia , Rosi Marzio , Troiani Anna
Published: November 2006

The first experimental detection of CS2OH is reported. CS2OH was observed for about one microsecond after its formation, as an intact isolated species in the gas phase. It was generated by electron transfer to the CS2OH+ ion, prepared in the source of a multisector mass spectrometer by suitable ion–molecule reactions. The vertical formation process allowed characterization of CS2OH by structural analysis of CS2OH+. Theoretical calculations were performed at the B3LYP/6‐311+G(2d,p) and CCSD(T)/aug‐cc‐pVTZ//B3LYP/6‐311+G(2d,p) levels of theory. The computed structure and stability of CS2OH and CS2OH+ as well as the energetics of the involved processes satisfactorily fit with the experimental results.
Polychromatic flow cytometry: A rapid method for the reduction and analysis of complex multiparameter data
Authors: Petrausch Ulf , Haley Daniel , Miller William , Floyd Kevin , Urba Walter J. , Walker Edwin
Published: November 2006

Background:

Recent advances in flow cytometry have resulted in the development of reliable techniques for performing polychromatic (5–17 color) flow cytometry analysis. However, the data reduction and analysis involved in the resolution of hundreds of possible cellular subphenotypes identified, using a single polychromatic flow cytometry staining panel, presents a major obstacle to the successful application of this technology.

Methods:

To generate two distinct collections of T cell populations with differentially expressed surface markers, cryopreserved lymph node cells from 5 melanoma patients vaccinated with the modified gp100209‐2M melanoma peptide were stimulated with cognate peptide and cultured in either IL‐21 + low‐dose IL‐2 or IL‐15 + low‐dose IL‐2. In vitro stimulated (IVS) cells were interrogated using 8‐color flow cytometry. Data were analyzed using Winlist Hyperlog™ and FCOM™ software, and 32 T cell subsets were resolved for each culture condition. Hierarchical clustering analysis was applied to the relative percentages of each subphenotype for both IVS conditions to determine if unique cell surface marker expression signatures were produced for each IVS culture.

Results:

Sequential data analysis using Hyperlog™ and FCOM™ demonstrated that lymphocytes cultured in IL‐21 + IL‐2 had a distinctively different set of subphenotype signatures compared to cells grown in IL‐15 + IL‐2 for all 5 patients. Importantly, subsequent cluster analysis of all 32 subphenotype frequencies in each IVS test condition for all 5 patients reproducibly demonstrated that cellular subphenotypes produced after IL‐21 + IL‐2 IVS partitioned separately from subphenotypes produced by IL‐15 + IL‐2 IVS.

Conclusions:

The integrated sequential use of Hyperlog™ and FCOM™ software with cluster analysis algorithms for the reduction and analysis of polychromatic flow cytometry data produces an effective, rapid technique for the assessment of complex patterns of subphenotype expression between and within multiple test samples. This approach to data analysis may enhance the use of polychromatic flow cytometry for both research and clinical applications. © 2006 International Society for Analytical Cytology