bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for a Pseudo-Outbreak of
Candida guilliermondii
Fungemia in a University Hospital in Brazil
Authors: Medeiros Eduardo Alexandrino Servolo , Lott Timothy J. , Colombo Arnaldo Lopes , Godoy Patrício , Coutinho Ana Paula , Braga Monica Santos , Nucci Marcio , Brandt Mary E.
Published: January 2007

Fungal infections due to
Candida
species represent an important cause of nosocomial bloodstream infections. We report a large pseudo-outbreak of
Candida guilliermondii
fungemia that occurred in a university hospital in Brazil.
C. guilliermondii
was identified in 64 (43%) of the 149 blood samples drawn between June 2003 and July 2004. The samples were from patients in different wards of the hospital but concentrated in pediatric units. None of the patients had clinical signs of fungemia, and observational analysis revealed errors in the collection of blood samples. During the investigation of the pseudo-outbreak,
C. guilliermondii
was isolated from environmental surfaces and from the skin and nails of members of the nursing team. Through a subtyping analysis it was found that some of the nonpatient isolates were highly related to the patient isolates, and all the patient isolates were highly related. This is consistent with the hypothesis that the pseudo-outbreak was from a limited number of common sources. The adoption of intervention measures was effective in resolving the outbreak, supporting the hypothesis that the outbreak was due to poor techniques of drawing blood samples for culture.
Intrarenal Abscesses Due to
Ureaplasma urealyticum
in a Transplanted Kidney
Authors: Eilers Elisabeth , Moter Annette , Bollmann Renate , Haffner Dieter , Querfeld Uwe
Published: January 2007

A young woman developed multiple abscesses in her transplanted kidney. Amplification of the 16S rRNA gene with subsequent sequencing revealed
Ureaplasma urealyticum
as the infectious agent. Microbiological diagnosis and sensitivity testing led to therapy with levofloxacin, resulting in rapid recovery of the patient.
PCR Detection of
Entamoeba histolytica
,
Entamoeba dispar
, and
Entamoeba moshkovskii
in Stool Samples from Sydney, Australia
Authors: Fotedar R. , Stark D. , Beebe N. , Marriott D. , Ellis J. , Harkness J.
Published: January 2007

This study investigated the presence of
Entamoeba histolytica
,
Entamoeba dispar
, and
Entamoeba moshkovskii
in stool samples from a patient population in Sydney, Australia. Stool samples were tested by microscopy and PCR. Five patients were found with
E. histolytica
infections, while
E. dispar
and
E. moshkovskii
were observed in 63 (70.8%) and 55 (61.8%) patients, respectively, by PCR. This is the first study in Australia using molecular techniques to determine the presence of
E. histolytica
,
E. dispar
, and
E. moshkovskii
.
Monitoring of Hepatitis C Virus Quasispecies in Chronic Infection by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Mutation Detection
Authors: Yea Carmen , Bukh Jens , Ayers Melissa , Roberts Eve , Krajden Mel , Tellier Raymond
Published: January 2007

Using both a mass spectrometry-based method and the classical method of cloning and sequencing, we demonstrated weekly changes in the hypervariable region 1 quasispecies of a chimpanzee infected with an infectious clone, coinciding with neutralizing antibody emergence. We also used the mass spectrometry method in the clinical follow-up of a chronically infected patient over a 5-year period.
An RNA-Binding Protein, hnRNP A1, and a Scaffold Protein, Septin 6, Facilitate Hepatitis C Virus Replication
Authors: Kim Chon Saeng , Seol Su Kyoung , Song Ok-Kyu , Park Ji Hoon , Jang Sung Key
Published: January 2007

Hepatitis C virus (HCV) is a positive-sense single-stranded RNA virus. NS5b is an RNA-dependent RNA polymerase that polymerizes the newly synthesized RNA. HCV likely uses host proteins for its replication, similar to other RNA viruses. To identify the cellular factors involved in HCV replication, we searched for cellular proteins that interact with the NS5b protein. HnRNP A1 and septin 6 proteins were identified by coimmunoprecipitation and yeast two-hybrid screening, respectively. Interestingly, septin 6 protein also interacts with hnRNP A1. Moreover, hnRNP A1 interacts with the 5′-nontranslated region (5′ NTR) and the 3′ NTR of HCV RNA containing the
cis
-acting elements required for replication. Knockdown of hnRNP A1 and overexpression of C-terminally truncated hnRNP A1 reduced HCV replication. In addition, knockdown of septin 6 and overexpression of N-terminally truncated septin 6 inhibited HCV replication. These results indicate that the host proteins hnRNP A1 and septin 6 play important roles in the replication of HCV through RNA-protein and protein-protein interactions.
Correct Capsid Assembly Mediated by a Conserved YXXLGL Motif in Prototype Foamy Virus Gag Is Essential for Infectivity and Reverse Transcription of the Viral Genome
Authors: Mannigel Ingrid , Stange Annett , Zentgraf Hanswalter , Lindemann Dirk
Published: January 2007

Unlike
other retrovirus Gag proteins, the prototype foamy virus (PFV)
p71

g

ag

protein is not processed
into mature matrix (MA), capsid (CA), and nucleocapsid (NC) subunits.
Little information about sequence motifs involved in FV capsid assembly
and release is available. The recent analysis of candidate L-domain
motifs in PFV Gag identified an evolutionarily conserved YXXL sequence
motif with a potential function in capsid assembly. Here we provide
support for the hypothesis that this motif does not function like a
conventional L domain, by demonstrating that, unlike the PFV Gag
PSAP L-domain motif, it cannot be functionally replaced by
heterologous L-domain sequences. Furthermore, mutation of individual
amino acids Y
464
, I
466
, L
467
, and
L
469
, but not E
465
, to alanine led to reduced
particle release and production of noninfectious, aberrant capsid
structures, although relative structural protein incorporation and
processing were not affected. In contrast, mutation of G
468
to alanine resulted in an intermediate, temperature-sensitive phenotype
characterized by reduced particle release and reduced infectivity.
Despite similar relative RNA genome incorporation for all mutants,
analysis and quantification of particle-associated viral nucleic acids
demonstrated defects in genomic reverse transcription for all the
noninfectious mutants, a process that, unlike that of
orthoretroviruses, in the case of FVs takes place in the
virus-producing cell. In correlation with the reduced infectivity, the
G
468
A mutant displayed an intermediate level of genomic
reverse transcription. Taken together, these results demonstrate that
the conserved YXXLGL motif in PFV Gag is involved in correct capsid
assembly, which in turn is essential for reverse transcription of the
FV
genome.
Cytoplasmic Localization of the ORF2 Protein of Hepatitis E Virus Is Dependent on Its Ability To Undergo Retrotranslocation from the Endoplasmic Reticulum
Authors: Surjit Milan , Jameel Shahid , Lal Sunil K.
Published: January 2007

Hepatitis E virus (HEV) is a positive-strand RNA virus that is prevalent in much of the developing world. ORF2 is the major capsid protein of HEV. Although ORF2 is an N-linked glycoprotein, it is abundantly located in the cytoplasm in addition to having membrane and surface localization. The mechanism by which ORF2 protein obtains access to the cytoplasm is unknown. In this report, we prove that initially all ORF2 protein is present in the endoplasmic reticulum and a fraction of it becomes retrotranslocated to the cytoplasm. The ability of ORF2 to be retrotranslocated is dependent on its glycosylation status and follows the canonical dislocation pathway. However, in contrast to general substrates of the dislocation pathway, retrotranslocated ORF2 protein is not a substrate of the 26S proteasome complex and is readily detectable in the cytoplasm in the absence of any protease inhibitor, suggesting that the retrotranslocated protein is stable in the cytoplasm. This study thus defines the pathway by which ORF2 obtains access to the cytoplasm.
Formation of a Multiple Protein Complex on the Adenovirus Packaging Sequence by the IVa2 Protein
Authors: Tyler Ryan E. , Ewing Sean G. , Imperiale Michael J.
Published: January 2007

During adenovirus virion assembly, the packaging sequence mediates the encapsidation of the viral genome. This sequence is composed of seven functional units, termed A repeats. Recent evidence suggests that the adenovirus IVa2 protein binds the packaging sequence and is involved in packaging of the genome. Study of the IVa2-packaging sequence interaction has been hindered by difficulty in purifying the protein produced in virus-infected cells or by recombinant techniques. We report the first purification of a recombinant untagged version of the adenovirus IVa2 protein and characterize its binding to the packaging sequence in vitro. Our data indicate that there is more than one IVa2 binding site within the packaging sequence and that IVa2 binding to DNA requires the A-repeat consensus, 5′-TTTG-(N
8
)-CG-3′. Furthermore, we present evidence that IVa2 forms a multimeric complex on the packaging sequence. These data support a model in which adenovirus DNA packaging occurs via the formation of a IVa2 multiprotein complex on the packaging sequence.
Mapping of the VP40-Binding Regions of the Nucleoprotein of Ebola Virus
Authors: Noda Takeshi , Watanabe Shinji , Sagara Hiroshi , Kawaoka Yoshihiro
Published: January 2007

Expression of Ebola virus nucleoprotein (NP) in mammalian cells leads to the formation of helical structures, which serve as a scaffold for the nucleocapsid. We recently found that NP binding with the matrix protein VP40 is important for nucleocapsid incorporation into virions (T. Noda, H. Ebihara, Y. Muramoto, K. Fujii, A. Takada, H. Sagara, J. H. Kim, H. Kida, H. Feldmann, and Y. Kawaoka, PLoS Pathog. 2:e99, 2006). To identify the region(s) on the NP molecule required for VP40 binding, we examined the interaction of a series of NP deletion mutants with VP40 biochemically and ultrastructurally. We found that both termini of NP (amino acids 2 to 150 and 601 to 739) are essential for its interaction with VP40 and for its incorporation into virus-like particles (VLPs). We also found that the C terminus of NP is important for nucleocapsid incorporation into virions. Of interest is that the formation of NP helices, which involves the N-terminal 450 amino acids of NP, is dispensable for NP incorporation into VLPs. These findings enhance our understanding of Ebola virus assembly and in so doing move us closer to the identification of targets for the development of antiviral compounds to combat Ebola virus infection.
Sialic Acid on Herpes Simplex Virus Type 1 Envelope Glycoproteins Is Required for Efficient Infection of Cells
Authors: Teuton Jeremy R. , Brandt Curtis R.
Published: January 2007

Herpes simplex virus type 1 (HSV-1) envelope proteins are posttranslationally modified by the addition of sialic acids to the termini of the glycan side chains. Although gC, gD, and gH are sialylated, it is not known whether sialic acids on these envelope proteins are functionally important. Digestion of sucrose gradient purified virions for 4 h with neuraminidases that remove both α2,3 and α2,6 linked sialic acids reduced titers by 1,000-fold. Digestion with a α2,3-specific neuraminidase had no effect, suggesting that α2,6-linked sialic acids are required for infection. Lectins specific for either α2,3 or α2,6 linkages blocked attachment and infection to the same extent. In addition, the mobility of gH, gB, and gD in sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels was altered by digestion with either α2,3 specific neuraminidase or nonspecific neuraminidases, indicating the presence of both linkages on these proteins. The infectivity of a gC-1-null virus, ΔgC2-3, was reduced to the same extent as wild-type virus after neuraminidase digestion, and attachment was not altered. Neuraminidase digestion of virions resulted in reduced VP16 translocation to the nucleus, suggesting that the block occurred between attachment and entry. These results show for the first time that sialic acids on HSV-1 virions play an important role in infection and suggest that targeting virion sialic acids may be a valid antiviral drug development strategy.
Assembly of Hepatitis Delta Virus: Particle Characterization, Including the Ability To Infect Primary Human Hepatocytes
Authors: Gudima Severin , He Yiping , Meier Anja , Chang Jinhong , Chen Rongji , Jarnik Michal , Nicolas Emmanuelle , Bruss Volker , Taylor John
Published: January 2007

Efficient assembly of hepatitis delta virus (HDV) was achieved by cotransfection of Huh7 cells with two plasmids: one to provide expression of the large, middle, and small envelope proteins of hepatitis B virus (HBV), the natural helper of HDV, and another to initiate replication of the HDV RNA genome. HDV released into the media was assayed for HDV RNA and HBV envelope proteins and characterized by rate-zonal sedimentation, immunoaffinity purification, electron microscopy, and the ability to infect primary human hepatocytes. Among the novel findings were that (i) immunostaining for delta antigen 6 days after infection with 300 genome equivalents (GE) per cell showed only 1% of cells as infected, but this was increased to 16% when 5% polyethylene glycol was present during infection; (ii) uninfected cells did not differ from infected cells in terms of albumin accumulation or the presence of E-cadherin at cell junctions; and (iii) sensitive quantitative real-time PCR assays detected HDV replication even when the multiplicity of infection was 0.2 GE/cell. In the future, this HDV assembly and infection system can be further developed to better understand the mechanisms shared by HBV and HDV for attachment and entry into host cells.
A Replication-Competent Adenovirus-Human Immunodeficiency Virus (Ad-HIV)tatand Ad-HIVenvPriming/Tat and Envelope Protein Boosting Regimen Elicits Enhanced Protective Efficacy against Simian/Human Immunodeficiency Virus SHIV89.6PChallenge in Rhesus Macaques
Authors: Demberg Thorsten , Florese Ruth H. , Heath Megan J. , Larsen Kay , Kalisz Irene , Kalyanaraman V. S. , Lee Eun Mi , Pal Ranajit , Venzon David , Grant Richard , Patterson L. Jean , Korioth-Schmitz Birgit , Buzby Adam , Dombagoda Dilani , Montefiori David C. , Letvin Norman L. , Cafaro Aurelio , Ensoli Barbara , Robert-Guroff Marjorie
Published: January 2007

We previously demonstrated that replication-competent adenovirus (Ad)-simian immunodeficiency virus (SIV) recombinant prime/protein boost regimens elicit potent immunogenicity and strong, durable protection of rhesus macaques against SIVmac251. Additionally, native Tat vaccines have conferred strong protection against simian/human immunodeficiency virus SHIV89.6Pchallenge of cynomolgus monkeys, while native, inactivated, or vectored Tat vaccines have failed to elicit similar protective efficacy in rhesus macaques. Here we asked if priming rhesus macaques with replicating Ad-human immunodeficiency virus (HIV)tatand boosting with the Tat protein would elicit protection against SHIV89.6P. We also evaluated a Tat/Env regimen, adding an Ad-HIVenvrecombinant and envelope protein boost to test whether envelope antibodies would augment acute-phase protection. Further, expecting cellular immunity to enhance chronic viremia control, we tested a multigenic group: Ad-HIVtat, -HIVenv, -SIVgag, and -SIVnefrecombinants and Tat, Env, and Nef proteins. All regimens were immunogenic. A hierarchy was observed in enzyme-linked immunospot responses (with the strongest response for Env, followed by Gag, followed by Nef, followed by Tat) and antibody titers (with the highest titer for Env, followed by Tat, followed by Nef, followed by Gag). Following intravenous SHIV89.6Pchallenge, all macaques became infected. Compared to controls, no protection was seen in the Tat-only group, confirming previous reports for rhesus macaques. However, the multigenic group blunted acute viremia by approximately 1 log (P= 0.017), and both the multigenic and Tat/Env groups reduced chronic viremia by 3 and 4 logs, respectively, compared to controls (multigenic,P= 0.0003; Tat/Env,P< 0.0001). The strikingly greater reduction in the Tat/Env group than in the multigenic group (P= 0.014) was correlated with Tat and Env binding antibodies. Since prechallenge anti-Env antibodies lacked SHIV89.6P-neutralizing activity, other functional anti-Env and anti-Tat activities are under investigation, as is a possible synergy between the Tat and Env immunogens.
The Glycoprotein Cytoplasmic Tail of Uukuniemi Virus (
Bunyaviridae
) Interacts with Ribonucleoproteins and Is Critical for Genome Packaging
Authors: Överby Anna K. , Pettersson Ralf F. , Neve Etienne P. A.
Published: January 2007

We have analyzed the importance of specific amino acids in the cytoplasmic tail of the glycoprotein G
N
for packaging of ribonucleoproteins (RNPs) into virus-like particles (VLPs) of
Uukuniemi virus
(UUK virus), a member of the
Bunyaviridae
family. In order to study packaging, we added the G
N
/G
C
glycoprotein precursor (p110) to a polymerase I-driven minigenome rescue system to generate VLPs that are released into the supernatant. These particles can infect new cells, and reporter gene expression can be detected. To determine the role of UUK virus glycoproteins in RNP packaging, we performed an alanine scan of the glycoprotein G
N
cytoplasmic tail (amino acids 1 to 81). First, we discovered three regions in the tail (amino acids 21 to 25, 46 to 50, and 71 to 81) which are important for minigenome transfer by VLPs. Further mutational analysis identified four amino acids that were important for RNP packaging. These amino acids are essential for the binding of nucleoproteins and RNPs to the glycoprotein without affecting the morphology of the particles. No segment-specific interactions between the RNA and the cytoplasmic tail could be observed. We propose that VLP systems are useful tools for analyzing protein-protein interactions important for packaging of viral genome segments, assembly, and budding of other members of the
Bunyaviridae
family.
DETECTING CORROSION RESISTANCE OF COATED STEEL REBARS BY ELECTROCHEMICAL TECHNIQUE (EIS)
Authors: RYOU J. , SHAH S.
Published: January 2007

Electrochemical impedance spectroscopy (EIS) is one of the electrochemical techniques used in materials science. The present measurements are used to evaluate the corrosion resistance of new types of coated steel rebar used in reinforced concrete. In this study, Si -based coating materials are used and evaluated, because adding Si to metals and alloys, including steel, generally increases their corrosion, oxidation, and erosion resistance. The result suggests that electrochemical impedance spectroscopy may be useful for monitoring corrosion activity on coated steel rebars. Based upon impedance changes, it appears that the silicon powder coating bonds well to the steel, and that the coating has a good performance.
STRUCTURAL AND PHOTOLUMINESCENCE PROPERTIES OF POROUS SILICON: EFFECT OF HF CONCENTRATION
Authors: NATARAJAN B. , RAMAKRISHNAN V. , VASU V. , RAMAMURTHY S.
Published: January 2007

Structural and Photoluminescence (PL) studies are carried out for p-type porous silicon materials prepared with different Hydrogen Fluoride (HF) concentration. Surface morphology of porous silicon was analyzed using atomic force microscope (AFM). Fourier Transform Infra Red (FTIR) spectra indicate that surface of porous silicon contain chemical species like SiH n. PL studies reveal that there is a prominent emission peak around 625 nm. No spectral shift is observed. It is further observed that the emission intensity increases with HF concentration. The PL of the porous silicon layer was found to come from its upper part, which was confirmed by a simulation of the PL spectrum employing an optical model. The refractive indices of the porous silicon layer were also determined through this simulation. The large hydrogen concentration in freshly prepared material has led to the suggestion that a silicon–hydrogen alloy effect is responsible for the luminescence.
EFFECT OF ANTIMONY AND FLUORINE DOPING ON ELECTRICAL, OPTICAL AND STRUCTURAL PROPERTIES OF TIN OXIDE FILMS PREPARED BY SPRAY PYROLYSIS METHOD
Authors: SHAMALA K. S. , MURTHY L. C. S. , NARASIMHA RAO K.
Published: January 2007

Undoped, antimony doped and fluorine doped tin oxide films have been prepared by spray pyrolysis technique. The films were deposited on glass substrates at temperatures ranging between 300°C and 370°C by spraying an alcoholic solution of tin tetra chloride ( SnCl 4). Dopants used were antimony tri chloride ( SbCl 3) for antimony doped tin oxide (ATO) films, and ammonium fluoride ( NH 4 F ) for fluorine doped tin oxide (FTO) films. Among undoped tin oxide films, the least resistivity was found to be 3.1 × 10-3 Ω-cm for a molar concentration of 0.75 M. In case of antimony doped films minimum resistivity value was found to be 7.7 × 10-4 Ω-cm for a film with ( Sb / Sn ) = 0.065, deposited at 370°C and in case of fluorine doped films it was found to be 1.67 × 10-3 Ω-cm for a doping percentage of 3 at% of fluorine in 0.1 M solution. The corresponding values of the carrier concentrations were found to be 1.8 × 1020/cm3 and 9.98 × 1020/cm3, respectively. The electrical and optical properties of these films were studied as a function of both doping concentration and substrate temperature. Doping percentage of antimony and fluorine in the spray solution has been optimized for achieving a minimum electrical resistivity. The dependence of electrical properties such as resistivity, carrier concentration and mobility of doped films were analyzed. Influence of antimony dopant on the optical band gap of the films has been reported on the basis of electron conduction mechanism. Air and argon annealing effects on the electrical properties of antimony doped tin oxide films were also studied.
SHALLOW DONORS IN A COUPLED TRIPLE GRADED QUANTUM WELL UNDER THE ELECTRIC AND MAGNETIC FIELDS
Authors: KASAPOGLU E. , SARI H. , SÖKMEN I.
Published: January 2007

The binding energy of the donor in three different shaped triple graded GaAs -( Ga , Al ) As quantum wells which is obtained by changing the depth of the central-well potential (Vo) is calculated by using a variational approach. The results have been obtained in the presence of uniform magnetic and electric fields applied along the growth direction as a function of the impurity position. In addition, we also give the binding energy of the hydrogenic donor impurity for triple square quantum wells having the same physical parameters with triple graded quantum well structures in order to see the effect of different geometric confinements on the donor impurity binding energy.
INVESTIGATION ON DEPTH OF HEAT AFFECTED ZONE OF DISCHARGE SPOT BY HIGH REPETITIVE RATE YAG LASER-INDUCED DISCHARGE TEXTURING
Authors: LI ZHENGYANG , YANG MINGJIANG , ZHONG MINLIN , LIU WENJIN
Published: January 2007

It is known that the press formability and the elongation of laser textured sheet are improved, and the service life of textured roll is longer than that of the un-textured roll due to hardening of the treated surface. One of the goals to develop high repetitive rate YAG laser-induced discharge texturing (LIDT) is to get deeper hardening zone. By observing and measuring cross-section of LIDT spots in different discharge conditions, it is found that the single-crater, which is formed by the discharge conditions of anode, which is covered by an oil film and with rectangular current waveform, has the most depth of heat affected zone (HAZ) comparing with other crater shapes when discharge energy is the same. The depth of HAZ is mainly depends on pulse duration when the discharge spot is single-crater. The results are analyzed.
EFFECT OF METAL ION ETCHING ON THE TRIBOLOGICAL, MECHANICAL AND MICROSTRUCTURAL PROPERTIES OF TiN-COATED D2 TOOL STEEL USING CAE PVD TECHNIQUE
Authors: ALI MUBARAK , HAMZAH ESAH BINTI , HJ. MOHD TOFF MOHD RADZI
Published: January 2007

A study has been made on TiN coatings deposited on D2 tool steel substrates by using commercially available cathodic arc evaporation, physical vapor deposition technique. The goal of this work is to determine the usefulness of TiN coatings in order to improve the micro-Vickers hardness, coefficient of friction and surface roughness of TiN coating deposited on tool steel, which is vastly use in tool industry for various applications. A pin-on-disc test was carried out to study the coefficient of friction versus sliding distance of TiN coating at various ion etching rates. The tribo-test showed that the minimum value recorded for friction coefficient was 0.386 and 0.472 with standard deviation of 0.056 and 0.036 for the coatings deposited at zero and 16 min ion etching. The differences in friction coefficient and surface roughness was mainly associated with the macrodroplets, which was produced during etching stage. The coating deposited for 16 min metal ion etching showed the maximum hardness, i.e., about five times higher than uncoated one and 1.24 times to the coating deposited at zero ion etching. After friction test, the wear track was observed by using field emission scanning electron microscope. The coating deposited for zero ion etching showed small amounts of macrodroplets as compared to the coating deposited for 16 min ion etching. The elemental composition on the wear scar were investigated by means of energy dispersive X-ray, indicate no further TiN coating on wear track. A considerable improvement in TiN coatings was recorded as a function of various ion etching rates.
IMPROVEMENT OF PHOTOCATALYTIC ACTIVITY OF TiO2 VIA COMBINED ROUTE OF METAL DOPING AND SURFACE ACIDIFICATION
Authors: LUAN YONG , FU PINGFENG , DAI XUEGANG
Published: January 2007

In the present work, a combined route involving first doping of iron or neodymium ions via sol–gel method followed by acidification of the metal-doped TiO 2 particles for the improvement of the photocatalytic capability of TiO 2 was reported. The obtained metal-doped/acidified TiO 2 photocatalysts were thoroughly characterized by X-ray diffraction, Fourier transform infrared analysis, and photoluminescence emission spectra. At the same time, their photocatalytic activities were evaluated in simulant photodegradation of methylene blue (MB). The results based on these characterizations showed that not only a rutile layer formed on the surface of original TiO 2 particles after surface cladding, but also the doped Fe or Nd ion had a favorable effect on suppression of the electron–hole recombination in the titania under ultraviolet light irradiation. Furthermore, the photocatalytic activity of the material obtained by Fe doping and acidification was substantially improved in comparison to the untreated TiO 2. However, the sample prepared from Nd -doping and acidification of TiO 2 showed decreased capability relative to the untreated TiO 2 in degradation of MB under similar conditions. Finally, the reason why the photocatalytic activities of the obtained catalysts are sensitive to the metal-doping was discussed in details.
SYNTHESIS, SPECTROSCOPIC, ac CONDUCTIVITY AND THERMAL STUDIES ONCo(III) ACETYLACETONATE-IODINE COMPLEX
Authors: HASHEM H. A. , REFAT M. S.
Published: January 2007

A spectrophotometric study of 1:1 donor–acceptor complex, cobalt (III) acetylacetonate (donor) and iodine (σ-acceptor) has been preformed. The equilibrium constants, (K) and the absorpitivity (ε) for the formation of the iodine complex have been calculated. The predicted structure of the solid triiodide charge-transfer complex reported in this study is further supported by thermal, far and mid infrared spectroscopic measurements. Electron transfer from Co (acac = 2, 4-pentanedionate)3to iodine leads to the formation of an organic semiconductor with the formula of [Formula: see text]. The kinetic parameters (nonisothermal method) for their decomposition have been evaluated by graphical methods using the equations of Freeman–Carroll (FC), Horowitz–Metzger (HM) and Coats–Redfern (CR). The ac conductivity and dielectric properties of [Formula: see text] have been measured over the frequency 50–106Hz at temperature 298 K.
HYDROXYAPATITE THIN FILMS ON TITANIUM DEPOSITED BY KrF LASER
Authors: BAO QUANHE , CHEN CHUANZHONG , WANG DIANGANG , ZHAO YAFAN , LEI TINGQUAN , LIU JUNMING
Published: January 2007

Pulsed laser deposition (PLD) is being investigated as an alternative technique to prepare hydroxyapatite coatings. In this research we studied the microstructure and phase composition of the PLD hydroxyapatite films. The surface morphology of the films is composed of droplets for which size ranges from hundreds of nanometers to a few micrometers. The cross-sectional morphology of the films shows that the films adhere to the substrate well and there are no microcracks, pores and other defects between substrate and films. The X-ray diffractometer results show that the deposited films are amorphous and the post heat treatment films consists of crystalline HA and TiO 2.
INFLUENCE OF Mg CONTENT ON TRAPPING EFFICIENCY IN Al–Mg SYSTEM BY POSITRON ANNIHILATION SPECTROSCOPY
Authors: BADAWI EMAD , ABDEL-RAHMAN M. A. , ABDELHAMED M. O.
Published: January 2007

PLT and Doppler broadening S-parameter were used for Al – Mg alloy, namely 5005, 5051, 5052 and 5083. The trapping efficiency was estimated for the pervious alloys as 2.42 × 109, 2.29 × 109, 2.24 × 109 and 2.27 × 109 s -1 cm 3, respectively and the trapping cross-section was estimated to be as 2.66 × 10-16, 2.14 × 10-16, 2.10 × 10-16 and 3.51 × 10-16 cm 2, respectively. It is clear that the mean lifetime and S-parameter have the same behavior as a function of deformation degree and saturated at the same value of thickness reduction.
FIRST PRINCIPLES SLAB RELAXATION STUDY OF THE TiFe(001) SURFACE
Authors: CANTO G. , ORDEJÓN PABLO
Published: January 2007

We have performed Density Functional Theory calculations in the Generalized Gradients Approximation for the (001) surface of the intermetallic compound TiFe . We have focused on the interplay between spin polarization and surface relaxations, and the influence of the chemical species at the surface. We found that the surface shows a magnetic ordering. The magnetic moment at the surface layer depends strongly on the surface termination, being much larger for the case of Fe than Ti termination (3.11 and 0.29 μB/atom, respectively). The magnetic moments show an alternating behavior with a slow decaying as we go inside the material. On the other hand, the modification of the atomic positions due to the surface relaxation results in a very small influence on the magnetic moment with respect to the ideal, nonrelaxed configuration.
Cardiac fibroblasts influence cardiomyocyte phenotype in vitro
Authors: LaFramboise W. A. , Scalise D. , Stoodley P. , Graner S. R. , Guthrie R. D. , Magovern J. A. , Becich M. J.
Published: January 2007

Cardiac fibroblasts impact myocardial development and remodeling through intercellular contact with cardiomyocytes, but less is known about noncontact, profibrotic signals whereby fibroblasts alter cardiomyocyte behavior. Fibroblasts and cardiomyocytes were harvested from newborn rat ventricles and separated by serial digestion and gradient centrifugation. Cardiomyocytes were cultured in 1) standard medium, 2) standard medium diluted 1:1 with PBS, or 3) standard medium diluted 1:1 with medium conditioned ≥72 h by cardiac fibroblasts. Serum concentrations were held constant under all media conditions, and complete medium exchanges were performed daily. Cardiomyocytes began contracting within 24 h at clonal or mass densities with <5% of cells expressing vimentin. Immunocytochemical analysis revealed progressive expression of α-smooth muscle actin in cardiomyocytes after 24 h in all conditions. Only cardiomyocytes in fibroblast-conditioned medium stopped contracting by 72 h. There was a significant, sustained increase in vimentin expression specific to these cultures (means ± SD: conditioned 46.3 ± 6.0 vs. control 5.3 ± 2.9%, P < 0.00025) typically with cardiac myosin heavy chain coexpression. Proteomics assays revealed 10 cytokines (VEGF, GRO/KC, monocyte chemoattractant protein-1, leptin, macrophage inflammatory protein-1α, IL-6, IL-10, IL-12p70, IL-17, and tumor necrosis factor-α) at or below detection levels in unconditioned medium that were significantly elevated in fibroblast-conditioned medium. Latent transforming growth factor-β and RANTES were present in unconditioned medium but rose to higher levels in conditioned medium. Only granulocyte-macrophage colony-stimulating factor was present above threshold levels in standard medium but decreased with fibroblast conditioning. These data indicated that under the influence of fibroblast-conditioned medium, cardiomyocytes exhibited marked hypertrophy, diminished contractile capacity, and phenotype plasticity distinct from the dedifferentiation program present under standard culture conditions.
Shrinkage insensitivity of NKCC1 in myosin II-depleted cytoplasts from Ehrlich ascites tumor cells
Authors: Hoffmann Else K. , Pedersen Stine F.
Published: January 2007

Protein phosphorylation/dephosphorylation and cytoskeletal reorganization regulate the Na+-K+-2Cl− cotransporter (NKCC1) during osmotic shrinkage; however, the mechanisms involved are unclear. We show that in cytoplasts, plasma membrane vesicles detached from Ehrlich ascites tumor cells (EATC) by cytochalasin treatment, NKCC1 activity evaluated as bumetanide-sensitive 86Rb influx was increased compared with the basal level in intact cells yet could not be further increased by osmotic shrinkage. Accordingly, cytoplasts exhibited no regulatory volume increase after shrinkage. In cytoplasts, cortical F-actin organization was disrupted, and myosin II, which in shrunken EATC translocates to the cortical region, was absent. Moreover, NKCC1 activity was essentially insensitive to the myosin light chain kinase (MLCK) inhibitor ML-7, a potent blocker of shrinkage-induced NKCC1 activity in intact EATC. Cytoplast NKCC1 activity was potentiated by the Ser/Thr protein phosphatase inhibitor calyculin A, partially inhibited by the protein kinase A inhibitor H89, and blocked by the broad protein kinase inhibitor staurosporine. Cytoplasts exhibited increased protein levels of NKCC1, Ste20-related proline- and alanine-rich kinase (SPAK), and oxidative stress response kinase 1, yet they lacked the shrinkage-induced plasma membrane translocation of SPAK observed in intact cells. The basal phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) was increased in cytoplasts compared with intact cells, yet in contrast to the substantial activation in shrunken intact cells, p38 MAPK could not be further activated by shrinkage of the cytoplasts. Together these findings indicate that shrinkage activation of NKCC1 in EATC is dependent on the cortical F-actin network, myosin II, and MLCK.
Recruitment of NADH shuttling in pressure-overloaded and hypertrophic rat hearts
Authors: Lewandowski E. Douglas , O'Donnell J. Michael , Scholz Thomas D. , Sorokina Natalia , Buttrick Peter M.
Published: January 2007

Glucose metabolism in the heart requires oxidation of cytosolic NADH from glycolysis. This study examines shuttling reducing equivalents from the cytosol to the mitochondria via the activity and expression of the oxoglutarate-malate carrier (OMC) in rat hearts subjected to 2 wk (Hyp2, n = 6) and 10 wk (Hyp10, n = 8) of pressure overload hypertrophy vs. that of sham-operated rats (Sham2, n = 6; and Sham10, n = 7). Moderate aortic banding produced increased atrial natriuretic factor (ANF) mRNA expression at 2 and 10 wk, but only at 10 wk did hearts develop compensatory hypertrophy (33% increase, P < 0.05). Isolated hearts were perfused with the short-chain fatty acid [2,4-13C2]butyrate (2 mM) and glucose (5 mM) to enable dynamic-mode 13C NMR of intermediate exchange across OMC. OMC flux increased before the development of hypertrophy: Hyp2 = 9.6 ± 2.1 vs. Sham2 = 3.7 ± 1.2 μM·min−1·g dry wt−1, providing an increased contribution of cytosolic NADH to energy synthesis in the mitochondria. With compensatory hypertrophy, OMC flux returned to normal: Hyp10 = 3.9 ± 1.7 vs. Sham10 = 3.8 ± 1.2 μM·g−1·min−1. Despite changes in activity, no differences in OMC expression occurred between Hyp and Sham groups. Elevated OMC flux represented augmented cytosolic NADH shuttling, coupled to increased nonoxidative glycolysis, in response to hypertrophic stimulus. However, development of compensatory hypertrophy moderated the pressure-induced elevation in OMC flux, which returned to control levels. The findings indicate that the challenge of pressure overload increases cytosolic redox state and its contribution to mitochondrial oxidation but that hypertrophy, before decompensation, alleviates this stress response.
Nephrogenic diabetes insipidus in mice caused by deleting COOH-terminal tail of aquaporin-2
Authors: Shi Peijun P. , Cao Xiao R. , Qu Jing , Volk Ken A. , Kirby Patricia , Williamson Roger A. , Stokes John B. , Yang Baoli
Published: January 2007

In mammals, the hormonal regulation of water homeostasis is mediated by the aquaporin-2 water channel (Aqp2) of the collecting duct (CD). Vasopressin induces redistribution of Aqp2 from intracellular vesicles to the apical membrane of CD principal cells, accompanied by increased water permeability. Mutations of AQP2 gene in humans cause both recessive and dominant nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin. In this study, we generated a line of mice with the distal COOH-terminal tail of the Aqp2 deleted ( Aqp2Δ 230), including the protein kinase A phosphorylation site (S256), but still retaining the putative apical localization signal (221–229) at the COOH-terminal. Mice heterozygous for the truncation appear normal. Homozygotes are viable to adulthood, with reduced urine concentrating capacity, increased urine output, decreased urine osmolality, and increased daily water consumption. Desmopressin increased urine osmolality in wild-type mice but had no effect on Aqp2Δ 230/Δ 230mice. Kidneys from affected mice showed CD and pelvis dilatation and papillary atrophy. By immunohistochemical and immunoblot analyses using antibody against the NH2-terminal region of the protein Aqp2Δ 230/Δ 230mice had a markedly reduced protein abundance. Expression of the truncated protein in MDCK cells was consistent with a small amount of functional expression but no stimulation. Thus we have generated a mouse model of NDI that may be useful in studying the physiology and potential therapy of this disease.
COX-2 activity transiently contributes to increased water and NaCl excretion in the polyuric phase after release of ureteral obstruction
Authors: Nørregaard Rikke , Jensen Boye L. , Topcu Sukru Oguzkan , Diget Maria , Schweer Horst , Knepper Mark A. , Nielsen Søren , Frøkiær Jørgen
Published: January 2007

Release of bilateral ureteral obstruction (BUO) is associated with reduced expression of renal aquaporins (AQPs), polyuria, and impairment of urine-concentrating capacity. Recently, we demonstrated that 24 h of BUO is associated with increased cyclooxygenase (COX)-2 expression in the inner medulla (IM) and that selective COX-2 inhibition prevents downregulation of AQP2. In the present study, we tested the hypothesis that COX-2 activity increases in the postobstructive phase and that this increase in COX-2 activity contributes to polyuria and impaired urine-concentrating capacity. We examined the effect of the selective COX-2 inhibitor parecoxib (5 mg·kg−1·day−1via osmotic minipumps) on renal functions and protein abundance of AQP2, AQP3, Na-K-2Cl cotransporter type 2 (NKCC2), and Na-K-ATPase 3 days after release of BUO. At 3 days after release of BUO, rats exhibited polyuria, dehydration and urine and IM tissue osmolality were decreased. There were inverse changes of COX-1 and COX-2 in the IM: COX-2 mRNA, protein, and activity increased, while COX-1 mRNA and protein decreased. Parecoxib reduced urine output 1 day after release of BUO, but sodium excretion and glomerular filtration rate were unchanged. Parecoxib normalized urinary PGE2and PGI2excretion and attenuated downregulation of AQP2 and AQP3, while phosphorylated AQP2 and NKCC2 remained suppressed. Parecoxib did not improve urine-concentrating capacity in response to 24 h of water deprivation. We conclude that decreased NKCC2 and collapse of the IM osmotic gradient, together with suppressed phosphorylated AQP2, are likely causes for the impaired urine-concentrating capacity and that COX-2 activity is not likely to mediate these changes in the chronic postobstructive phase after ureteral obstruction.
Angiotensin II-induced genomic damage in renal cells can be prevented by angiotensin II type 1 receptor blockage or radical scavenging
Authors: Schupp Nicole , Schmid Ursula , Rutkowski Przemyslaw , Lakner Ursula , Kanase Nilesh , Heidland August , Stopper Helga
Published: January 2007

Hypertensive patients exhibit elevated cancer incidence, especially of cancers of the kidney. Elevated levels of ANG II, the active peptide of the renin-angiotensin system, regulating blood pressure and cardiovascular homeostasis, are known to cause hypertension and kidney diseases. There is evidence that ANG II is an activator of NAD(P)H oxidase, leading to the formation of free radicals, which are known to participate in the induction of DNA damage. This study was undertaken to characterize ANG II-induced DNA damage. DNA damage was measured by comet assay and micronucleus frequency test. Incubation of pig kidney cells (LLC-PK1) in vitro with ANG II concentrations between 85 and 340 nM led to a 6- to 15-fold increase of DNA damage compared with the control as revealed by comet assay analysis. Micronuclei were induced about fourfold compared with the control in pig and rat kidney cells (LLC-PK1, NRK) and in human promyelocytic cells (HL-60). ANG II-induced DNA damage could be prevented by coincubation with the ANG II type 1 receptor blocker candesartan and the antioxidants N-acetylcysteine and α-tocopherol. The ANG II type 2 receptor antagonist PD123319 could not reduce ANG II-induced DNA damage. Measurement of reactive oxygen species (ROS) by flow cytometry showed an enhanced formation after exposure to ANG II and a reduction of ROS after candesartan, N-acetylcysteine, and α-tocopherol. The present findings support our hypothesis that ANG II causes DNA damage via ANG II type 1 receptor binding and subsequent formation of oxidative stress.
Cytokine-mediated regulation of urea transporters during experimental endotoxemia
Authors: Schmidt Christoph , Höcherl Klaus , Bucher Michael
Published: January 2007

Acute renal failure (ARF) is a frequent complication of sepsis and has a high mortality. Sepsis-induced ARF is known to be associated with significant impairment of tubular capacity. However, the pathogenesis of endotoxemic tubular dysfunction with failure of urine concentration is poorly understood. Urea plays an important role in the urinary concentrating mechanism and expression of the urea transporters UT-A1, UT-A2, UT-A3, UT-A4, and UT-B is essential for tubular urea reabsorption. The present study attempts to assess the regulation of renal urea transporters during severe inflammation in vivo. Lipopolysaccharide-(LPS)-injected mice presented with reduced glomerular filtration rate, fractional urea excretion, and inner medulla osmolality associated with a marked decrease in expression of all renal urea transporters. Similar alterations were observed after application of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interferon (IFN)-γ, or IL-6. LPS-induced downregulation of urea transporters was not affected in knockout mice with deficient TNF-α, IL-receptor-1, IFN-γ, or IL-6. Glucocorticoid treatment inhibited LPS-induced increases of tissue TNF-α, IL-1β, IFN-γ, or IL-6 concentration, diminished LPS-induced renal dysfunction, and attenuated the downregulation of renal urea transporters. Renal ischemia induced by renal artery clipping did not influence the expression of urea transporters. Our data demonstrate that renal urea transporters are downregulated by severe inflammation, which likely accounts for tubular dysfunction. Furthermore, they suggest that the downregulation of renal urea transporters during LPS-induced ARF is mediated by proinflammatory cytokines and is independent from renal ischemia because of sepsis-induced hypotension.
Ventilatory and perceptual responses to cycle exercise in obese women
Authors: Ofir Dror , Laveneziana Pierantonio , Webb Katherine A. , O'Donnell Denis E.
Published: January 2007

The main purpose of this study was to examine the relative contribution of respiratory mechanical factors and the increased metabolic cost of locomotion to exertional breathlessness in obese women. We examined the relationship of intensity of breathlessness to ventilation (V̇e) when exertional oxygen uptake (V̇o2) of obesity was minimized by cycle exercise. Eighteen middle-aged (54 ± 8 yr, mean ± SD) obese [body mass index (BMI) 40.2 ± 7.8 kg/m2] and 13 age-matched normal-weight (BMI 23.3 ± 1.7 kg/m2) women were studied. Breathlessness at higher submaximal cycle work rates was significantly increased (by ≥1 Borg unit) in obese compared with normal-weight women, in association with a 35–45% increase in V̇e and a higher metabolic cost of exercise. Obese women demonstrated greater resting expiratory flow limitation, reduced resting end-expiratory lung volume (EELV)(by 20%), and progressive increases in dynamic EELV during exercise: peak inspiratory capacity (IC) decreased by 16% (0.39 liter) of the resting value. V̇e/V̇o2 slopes were unchanged in obesity. Breathlessness ratings at any given V̇e or V̇o2 were not increased in obesity, suggesting that respiratory mechanical factors were not contributory. Our results indicate that in obese women, recruitment of resting IC and dynamic increases in EELV with exercise served to optimize operating lung volumes and to attenuate expiratory flow limitation so as to accommodate the increased ventilatory demand without increased breathlessness.
Leptin receptors in human skeletal muscle
Authors: Guerra Borja , Santana Alfredo , Fuentes Teresa , Delgado-Guerra Safira , Cabrera-Socorro Alfredo , Dorado Cecilia , Calbet Jose A. L.
Published: January 2007

Human skeletal muscle expresses leptin receptor mRNA; however, it remains unknown whether leptin receptors (OB-R) are also expressed at the protein level. Fourteen healthy men (age = 33.1 ± 2.0 yr, height = 175.9 ± 1.7 cm, body mass = 81.2 ± 3.8 kg, body fat = 22.5 ± 1.9%; means ± SE) participated in this investigation. The expression of OB-R protein was determined in skeletal muscle, subcutaneous adipose tissue, and hypothalamus using a polyclonal rabbit anti-human leptin receptor. Three bands with a molecular mass close to 170, 128, and 98 kDa were identified by Western blot with the anti-OB-R antibody. All three bands were identified in skeletal muscle: the 98-kDa and 170-kDa bands were detected in hypothalamus, and the 98-kDa and 128-kDa bands were detected in thigh subcutaneous adipose tissue. The 128-kDa isoform was not detected in four subjects, whereas in the rest its occurrence was fully explained by the presence of intermuscular adipose tissue, as demonstrated using an anti-perilipin A antibody. No relationship was observed between the basal concentration of leptin in serum and the 170-kDa band density. In conclusion, a long isoform of the leptin receptor with a molecular mass close to 170 kDa is expressed at the protein level in human skeletal muscle. The amount of 170-kDa protein appears to be independent of the basal concentration of leptin in serum.