bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoprenoid biosynthesis as a target for antibacterial and antiparasitic drugs: phosphonohydroxamic acids as inhibitors of deoxyxylulose phosphate reducto-isomerase
Authors: KUNTZ Lionel , TRITSCH Denis , GROSDEMANGE-BILLIARD Catherine , HEMMERLIN Andréa , WILLEM Audrey , BACH Thomas J. , ROHMER Michel
Published: February 2005

Isoprenoid biosynthesis via the methylerythritol phosphate pathway is a target against pathogenic bacteria and the malaria parasite Plasmodium falciparum. 4-(Hydroxyamino)-4-oxobutylphosphonic acid and 4-[hydroxy(methyl)amino]-4-oxobutyl phosphonic acid, two novel inhibitors of DXR (1-deoxy-D-xylulose 5-phosphate reducto-isomerase), the second enzyme of the pathway, have been synthesized and compared with fosmidomycin, the best known inhibitor of this enzyme. The latter phosphonohydroxamic acid showed a high inhibitory activity towards DXR, much like fosmidomycin, as well as significant antibacterial activity against Escherichia coli in tests on Petri dishes.
Ribosomal protein S2 is a substrate for mammalian PRMT3 (protein arginine methyltransferase 3)
Authors: SWIERCZ Rafal , PERSON Maria D. , BEDFORD Mark T.
Published: February 2005

PRMT3 (protein arginine methyltransferase 3) is one of four type I arginine methyltransferases that catalyse the formation of asymmetric dimethylarginine. PRMT3 is unique in that its N-terminus harbours a C2H2 zinc-finger domain that is proposed to confer substrate specificity. In addition, PRMT3 is the only type I enzyme that is restricted to the cytoplasm. Known in vitro substrates for PRMT3 include GST–GAR (a glutathione S-transferase fusion protein containing the glycine- and arginine-rich N-terminal region of fibrillarin), Sam68 (Src-associated substrate during mitosis 68 kDa) and PABP-N1 [poly(A)-binding protein-N1; PABP2]. Here we report the identification of an in vivo substrate for mammalian PRMT3. We found that FLAG-tagged PRMT3 can ‘pull down’ a protein with a molecular mass of 30 kDa from HeLa cell extracts. MS identified this PRMT3-interacting protein as rpS2 (ribosomal protein S2). In vitro studies showed that the zinc-finger domain of PRMT3 is necessary and sufficient for binding to rpS2. In addition, rpS2 is methylated by PRMT3 in vitro and is also methylated in cell lines. Deletion analysis of the rpS2 amino acid sequence identified a N-terminal Arg-Gly repeat as the methylation site. Furthermore, both PRMT3 and rpS2 co-sediment with free ribosomal subunits. These studies implicate PRMT3 in ribosomal function and in the regulation of protein synthesis.
Isotropic proton-detected local-field nuclear magnetic resonance in solids
Authors: Havlin Robert H. , Walls Jamie D. , Pines Alexander
Published: February 2005

A nuclear magnetic resonance method is presented which produces linear, isotropic proton-detected local-field spectra for INS spin systems in powdered samples. The method, heteronuclear isotropic evolution (HETIE), refocuses the anisotropic portion of the heteronuclear dipolar coupling frequencies by evolving the system under a series of specially designed Hamiltonians and evolution pathways. The theory behind HETIE is presented along with experimental studies conducted on a powdered sample of ferrocene, demonstrating the methodology outlined in this paper. Applications of HETIE for use in structure determination in the solid state are discussed.
Sz.-Nagy–Foias theory and Lax–Phillips type semigroups in the description of quantum mechanical resonances
Authors: Strauss Y.
Published: February 2005

A quantum mechanical version of the Lax–Phillips scattering theory was recently developed. This theory is a natural framework for the description of quantum unstable systems. However, since the spectrum of the generator of evolution in this theory is unbounded from below, the existing framework does not apply to a large class of quantum mechanical scattering problems. It is shown in this work that the fundamental mathematical structure underlying the Lax–Phillips theory, i.e., the Sz.-Nagy–Foias theory of contraction operators on Hilbert space, can be used for the construction of a formalism in which models associated with a semibounded spectrum may be accomodated.
Optical pumping of IV-VI semiconductor multiple quantum well materials using a GaSb-based laser with emission at λ=2.5μm
Authors: McCann P. J. , Kamat P. , Li Y. , Sow A. , Wu H. Z. , Belenky G. , Shterengas L. , Kim J. G. , Martinelli R.
Published: February 2005

Room-temperature photoluminescence (PL) measurements of IV-VI semiconductor multiple quantum well (MQW) structures using diode laser optical pumping at two different excitation wavelengths, 2.5 and 0.91μm, are described. Active region temperatures during continuous-wave optical pumping were determined from blueshifts in PL emission energies. Temperatures were between 22.7 and 29.5°C lower for 2.5-μm pumping as compared to 0.91-μm pumping at the same power level of 100mW. Heating effects are also shown to be smaller for MQW samples with more narrow PbSe wells.
In situ magnetoresistance measurements during nanopatterning of pseudo-spin-valve structures
Authors: Morecroft D. , Van Aken B. B. , Prieto J. L. , Kang D.-J. , Burnell G. , Blamire M. G.
Published: February 2005

In this article, we explore the mechanisms involved in the change in magnetoresistance (MR) as a pseudo spin valve (PSV) of the form NiFe(15nm)∕Cu(2.2nm)∕NiFe(6nm) is patterned into a nanowire array. We have used in situ measurements to investigate the change in the performance of the PSV for different milling depths and wire widths. Micromagnetic simulations have been used in combination with the experimental data to help interpret the results. As the milling depth increases the giant magnetoresistance (GMR) increases, due to an increase in the antiparallel alignment between the two ferromagnetic layers. The increase in GMR is accompanied by a large increase in the reversal field of the thicker layer, while the thinner layer reversal field remains approximately the same throughout the milling. A maximum GMR is observed when the structure is fully milled into a nanowire array. Closure domains at the ends of the wires dominate the reversal process.
Technique for x-ray markers at high pressure in the diamond anvil cell
Authors: Ruoff Arthur L. , Sun Liling , Natarajan Subramanian , Zha Chang-Sheng , Stupian Gary
Published: February 2005

X-ray markers as powder or foil can interfere with optical studies on a sample. Use of the gasket itself as an x-ray marker requires careful collimation of the x-ray beam so that only the gasket material adjacent to the sample is studied. (The pressure drops rapidly as the radius increases in the gasket.) By depositing a thin half-micron thick marker on the wall of the sample hole, these problems are eliminated and a large beam can be used, but for pressure measurements only the submicron layer will be involved.
Thin-film InGaN multiple-quantum-well light-emitting diodes transferred from Si (111) substrate onto copper carrier by selective lift-off
Authors: Zhang Baijun , Egawa Takashi , Ishikawa Hiroyasu , Liu Yang , Jimbo Takashi
Published: February 2005

Crack-free thin-film InGaN multiple-quantum-well light-emitting diodes (LEDs) were successfully transferred from the original Si (111) substrate onto copper carrier by means of metal-to-metal bonding and the selective lift-off (SLO) technique using wet-chemical etching. Crystalline quality was investigated by x-ray diffraction and photoluminescence measurements. No deterioration was found in the thin film after substrate removal due to the fact that the SLO technique minimizes the residual strain relaxation. Substrate removal eliminates not only the substrate absorption but also the large band offset between the AlN buffer layer and substrate. In conjunction with inserting a metal reflector between the LED structure and the copper carrier, the performances of the LED fabricated on the substrate removal region were significantly improved. The operating voltage at 20mA and the series resistance was 3.6V and 27Ω, respectively. The optical power revealed an increase of 49% compared to the LED before substrate removal.
Growth and in situ annealing conditions for long-wavelength (Ga, In)(N, As)/GaAs lasers
Authors: Damilano B. , Barjon J. , Duboz J.-Y. , Massies J. , Hierro A. , Ulloa J.-M. , Calleja E.
Published: February 2005

The conjugated effect of growth temperature and in situ thermal annealing on the photoluminescence properties of In0.4Ga0.6As0.985N0.015/GaAs quantum wells (QWs) grown by molecular-beam epitaxy has been investigated. The interplay between growth temperature and annealing effects is such as the optimum growth temperature is not the same for as-grown and annealed samples. By using the combination of a low growth temperature and a high in situ annealing temperature, separate confinement heterostructure laser diodes with a single In0.4Ga0.6As1−xNx (x=0.015–0.021)/GaAs QW have been grown. The broad area devices emit from 1.34 to 1.44 μm at room temperature with a threshold current density of 1500–1755A∕cm2.
Ferromagnetic nanoclusters formed by Mn implantation in GaAs
Authors: Couto O. D. D. , Brasil M. J. S. P. , Iikawa F. , Giles C. , Adriano C. , Bortoleto J. R. R. , Pudenzi M. A. A. , Gutierrez H. R. , Danilov I.
Published: February 2005

Ferromagnetic clusters were incorporated into GaAs samples by Mn implantation and subsequent annealing. The composition and structural properties of the Mn-based nanoclusters formed at the surface and buried into the GaAs sample were analyzed by x-ray and microscopic techniques. Our measurements indicate the presence of buried MnAs nanoclusters with a structural phase transition around 40 °C, in accord with the first-order magneto-structural phase transition of bulk MnAs. We discuss the structural behavior of these nanoclusters during their formation and phase transition, which is an important point for technological applications.
Numerical extraction of distributions of space-charge and polarization from laser intensity modulation method
Authors: Tuncer Enis , Lang Sidney B.
Published: February 2005

The Fredholm integral equation of the laser intensity modulation method is an ill-conditioned problem with multiple solutions. An approach based on an application of the Monte Carlo technique and a least-squares solver is developed and tested on simulated data containing both Gaussian and white noise. Good agreement between the original polarization and the estimated one was found. The influences of bin size and spacing, and errors in material properties, are discussed. It is shown that the presented approach is an alternative to other data analysis techniques in the literature based on regularization algorithms.
A Si nanopillar grown on a Si tip by atomic force microscopy in ultrahigh vacuum for a high-quality scanning probe
Authors: Arai Toyoko , Tomitori Masahiko
Published: February 2005

We grow a Si nanopillar on a commercial Si tip on an atomic force microscopy (AFM) cantilever using AFM in ultrahigh vacuum for a high-quality scanning force probe, and observe noncontact-AFM (nc-AFM) images of Si(111)7×7 and Ge deposited Si(111) with the nanopillar. We observe it ex situ by transmission electron microscopy to confirm its growth and crystallinity. The nc-AFM image clearly showed the high performance of the nanopillar as a probe with respect to the spatial resolution, image stability, and reproducibility. This nanopillar growth technique can elongate the lifetime of the cantilever and be applied to other materials.
High-resolution x-ray diffraction and transmission electron microscopy of multiferroic BiFeO3 films
Authors: Qi Xiaoding , Wei Ming , Lin Yuan , Jia Quanxi , Zhi Dan , Dho Joonghoe , Blamire Mark G. , MacManus-Driscoll Judith L.
Published: February 2005

High-resolution x-ray diffraction and transmission electron microscopy (TEM) have been used to study BiFeO3 thin films grown on the bare and SrRuO3 buffered (001) SrTiO3 substrates. Reciprocal space mapping (RSM) around (002) and (103) reflections revealed that BFO films with a thickness of about 200 nm were almost fully relaxed and had a rhombohedral structure. Cross-sectional, high-resolution TEM showed that the films started to relax at a very early stage of growth, which was consistent with the RSM results. A thin intermediate layer of about 2 nm was observed at the interface, which had a smaller lattice than the overgrown film. Twist distortions about the c axis to release the shear strain introduced by the growth of rhombic (001) BiFeO3 on cubic (001) SrTiO3 were also observed. The results indicate that a strained, coherent BiFeO3 film on (001) SrTiO3 is very difficult to maintain and (111) STO substrates are preferable.
Buried waveguides in terahertz quantum cascade lasers based on two-dimensional surface plasmon modes
Authors: Alton J. , Dhillon S. S. , Sirtori C. , de Rossi A. , Calligaro M. , Barbieri S. , Beere H. E. , Linfield E. H. , Ritchie D. A.
Published: February 2005

A scheme for buried waveguides in terahertz quantum cascade lasers is demonstrated by combining a surface plasmon mode with ion implantation. The mode is bound to a metal strip deposited on the surface of the device that confines the light in both vertical and lateral directions without any etching requirements. Ion implantation is used to confine the current that selectively pumps the active region. Electrical and optical measurements demonstrate this two-dimensional confinement. Further, by taking advantage of the lower losses and a reduced thermal resistance, laser action is achieved in continuous wave up to 77K.
100% fluorescence efficiency of 4,4′-bis[(N-carbazole)styryl]biphenyl in a solid film and the very low amplified spontaneous emission threshold
Authors: Aimono Takanori , Kawamura Yuichiro , Goushi Kenichi , Yamamoto Hidetoshi , Sasabe Hiroyuki , Adachi Chihaya
Published: February 2005

We examined the amplified spontaneous emission (ASE) characteristics of fluorescent styrylbenzene derivatives doped into a 4,4′-di(N-carbazolyl)biphenyl (CBP) host. In particular, 4,4′-bis[(N-carbazole)styryl]biphenyl (BSB-Cz) demonstrated an extremely low ASE threshold of Eth=0.32±0.05μJ∕cm2. We observed that the 6 wt %-BSB-Cz:CBP film has an ultimate photoluminescence (PL) quantum efficiency of ϕPL=100% and a short transient lifetime of τf=1.0±0.1ns, leading to a large radiative decay rate of kr=1×109s−1. We demonstrated that the extremely low ASE threshold originated from the large radiative decay rate of BSB-Cz.
Nucleoplasmin regulates chromatin condensation during apoptosis
Authors: Lu Zhigang , Zhang Chuanmao , Zhai Zhonghe
Published: February 2005

Although chromatin condensation is one of the hallmarks of apoptosis, its relationship with DNA fragmentation has been controversial. We show here that apoptotic chromatin condensation is regulated by nucleoplasmin, a protein that decondenses sperm chromatin during male pronuclear assembly. In
Xenopus
egg extracts, nucleoplasmin is tyrosine-dephosphorylated during apoptosis. This dephosphorylation inactivates the chromatin decondensation activity of nucleoplasmin and leads to its exclusion from the chromatin. Inhibition of tyrosine dephosphorylation prevents apoptotic chromatin condensation but not DNA fragmentation. Studies with mutant proteins indicate that dephosphorylation of nucleoplasmin at Tyr-124 regulates chromatin condensation through changes in the interaction of nucleoplasmin with chromatin and the loss of its chromatin decondensation activity. These results show that chromatin condensation and DNA fragmentation are independent processes.
Plasmodium
liver stage developmental arrest by depletion of a protein at the parasite–host interface
Authors: Mueller Ann-Kristin , Camargo Nelly , Kaiser Karine , Andorfer Cathy , Frevert Ute , Matuschewski Kai , Kappe Stefan H. I.
Published: February 2005

Plasmodium
parasites of mammals, including the species that cause malaria in humans, infect the liver first and develop there into clinically silent liver stages. Liver stages grow and ultimately produce thousands of first-generation merozoites, which initiate the erythrocytic cycles causing malaria pathology. Here, we present a
Plasmodium
protein with a critical function for complete liver stage development.
UIS4
(up-regulated in infective sporozoites gene 4) is expressed exclusively in infective sporozoites and developing liver stages, where it localizes to the parasitophorous vacuole membrane. Targeted gene disruption of
UIS4
in the rodent model malaria parasite
Plasmodium berghei
generated knockout parasites that progress through the malaria life cycle until after hepatocyte invasion but are severely impaired in further liver stage development. Immunization with
UIS4
knockout sporozoites completely protects mice against subsequent infectious WT sporozoite challenge. Genetically attenuated liver stages may thus induce immune responses, which inhibit subsequent infection of the liver with WT parasites.
A noncanonical E-box enhancer drives mouse
Period2
circadian oscillations
in vivo
Authors: Yoo Seung-Hee , Ko Caroline H. , Lowrey Phillip L. , Buhr Ethan D. , Song Eun-joo , Chang Suhwan , Yoo Ook Joon , Yamazaki Shin , Lee Choogon , Takahashi Joseph S.
Published: February 2005

The mouse
Period2
(
mPer2
) locus is an essential negative-feedback element of the mammalian circadian-clock mechanism. Recent work has shown that
mPer2
circadian gene expression persists in both central and peripheral tissues. Here, we analyze the mouse
mPer2
promoter and identify a circadian enhancer (E2) with a noncanonical 5′-CACGTT-3′ E-box located 20 bp upstream of the
mPer2
transcription start site. The E2 enhancer accounts for most circadian transcriptional drive of the
mPer2
locus by CLOCK:BMAL1, is a major site of DNaseI hypersensitivity in this region, and is constitutively bound by a transcriptional complex containing the CLOCK protein. Importantly, the E2 enhancer is sufficient to drive self-sustained circadian rhythms of luciferase activity in central and peripheral tissues from
mPer2-E2
::
Luciferase
transgenic mice with tissue-specific phase and period characteristics. Last, genetic analysis with mutations in
Clock
and
Bmal1
shows that the E2 enhancer is a target of CLOCK and BMAL1
in vivo
.
Lipopolysaccharides as a communication signal for progression of legume endosymbiosis
Authors: Mathis René , Van Gijsegem Frédérique , De Rycke Riet , D'Haeze Wim , Van Maelsaeke Els , Anthonio Erin , Van Montagu Marc , Holsters Marcelle , Vereecke Danny
Published: February 2005

Establishment of a successful symbiosis between rhizobia and legumes results from an elaborate molecular dialogue between both partners. Bacterial nodulation (Nod) factors are indispensable for initiating plant responses, whereas bacterial surface polysaccharides are important for infection progression and nodule development. The mutant ORS571-oac2 of
Azorhizobium caulinodans
, affected in its surface polysaccharides, provokes a defective interaction with its host
Sesbania rostrata
. ORS571-oac2 induced structures with retarded development and continued generation of infection centers and organ primordia, leading to multilobed ineffective nodules. Bacterial development throughout the interaction occurred without major defects. A functional bidirectional complementation was obtained upon coinfection of ORS571-oac2 and a Nod factor-deficient mutant, indicating that the Fix
-
phenotype of ORS571-oac2-induced nodules resulted from the absence of a positive signal from ORS571-oac2. Indeed, the Fix
-
phenotype could be complemented by coinoculation of ORS571-oac2 with lipopolysaccharides (LPSs) purified from
A. caulinodans
. Our data show that Nod factors and LPSs are consecutive signals in symbiosis. Nod factors act first to trigger the onset of the nodulation and invasion program; LPSs inform the plant to proceed with the symbiotic interaction and to develop a functional fixation zone.
Characterization of CD56–/CD16+natural killer (NK) cells: A highly dysfunctional NK subset expanded in HIV-infected viremic individuals
Authors: Mavilio Domenico , Lombardo Gabriella , Benjamin Janet , Kim Diana , Follman Dean , Marcenaro Emanuela , O'Shea M. Angeline , Kinter Audrey , Kovacs Colin , Moretta Alessandro , Fauci Anthony S.
Published: February 2005

Natural killer (NK) cells are an important component of the innate immune response against viral infections. NK cell-mediated cytolytic activity is defective in HIV-infected individuals with high levels of viral replication. In the present study, we examined the phenotypic and functional characteristics of an unusual CD56–/CD16+(CD56–) NK subset that is greatly expanded in HIV-viremic individuals. The higher level of expression of inhibitory NK receptors and the lower level of expression of natural cytotoxicity receptors observed in the CD56–NK fraction compared with that of CD56+NK cells was associated with extremely poorin vitrocytotoxic function of this subset. In addition, the secretion of certain cytokines known to be important in initiating antiviral immune responses was markedly reduced in the CD56–, as compared with the CD56+NK cell subset. These data suggest that the expansion of this highly dysfunctional CD56–NK cell subset in HIV-viremic individuals largely accounts for the impaired function of the total NK cell population.
Family average income and body mass index above the healthy weight range among urban and rural residents in regional Mainland China
Authors: Xu Fei , Yin Xiao-Mei , Zhang Min , Leslie Eva , Ware Robert , Owen Neville
Published: February 2005

Objective

To explore the relationship between family average income (FAI; an index of socio-economic status) and body mass index (BMI; a widely used, inexpensive indicator of weight status) above the healthy weight range in a region of Mainland China.

Design

Population-based cross-sectional study, conducted between October 1999 and March 2000 on a sample of regular local residents aged 35 years or older who were selected by random cluster sampling.

Setting

Forty-five administrative villages selected from three urban districts and two rural counties of Nanjing municipality, Mainland China, with a regional population of 5.6 million.

Subjects

In total, 29 340 subjects participated; 67.7% from urban and 32.3% from rural areas; 49.8% male and 50.2% female. The response rate among eligible participants was 90.1%.

Results

The proportion of participants classified as overweight was 30.5%, while 7.8% were identified as obese. After adjusting for possible confounding variables (age, gender, area of residence, educational level, occupational and leisure-time physical activity, daily vegetable consumption and frequency of red meat intake), urban participants were more likely to be overweight or obese relative to their rural counterparts, more women than men were obese, and participants in the lowest FAI tertile were the least likely to be above the healthy weight range.

Conclusions

The proportion of adults with BMI above the healthy weight range was positively related to having a higher socio-economic status (indexed by FAI) in a regional Chinese population.
Associations between parental report of the home food environment and adolescent intakes of fruits, vegetables and dairy foods
Authors: Hanson Nicole I , Neumark-Sztainer Dianne , Eisenberg Marla E , Story Mary , Wall Melanie
Published: February 2005

Objective

This study examines parental report of household food availability, parent dietary intake and associations with adolescent intakes of fruits, vegetables and dairy foods.

Design

Cross-sectional study. Adolescents completed the Project EAT survey and the Youth Adolescent Food Frequency Questionnaire at school. Parents of adolescents were interviewed by telephone about the home food environment, eating habits and weight-related behaviours. General linear modelling was used to compare dietary intakes of adolescents across different levels of household food availability and parental intakes.

Subjects/setting

The study sample included 902 adolescents and their parent or guardian.

Results

Many parents were not consuming the minimum number of daily recommended fruit (44.5%), vegetable (69.9%) or dairy (46.9%) servings. While most parents reported that fruits and vegetables were available at home (90.3%) and vegetables were usually served at dinner (87.0%), fewer parents reported milk was served at meals (66.6%). Soft drinks were usually available at home (56.8%). Among girls, household availability was positively associated with fruit and vegetable intake (ttrend = 2.70, P < 0.01) and soft drink availability was inversely associated with dairy intake (ttrend = 2.08, P = 0.04). Among boys, serving milk at meals was positively associated with dairy intake (ttrend = 3.65, P < 0.01). Parental intakes were positively associated with dairy intake for boys (ttrend = 2.04, P = 0.04), and with dairy (ttrend = 2.43, P = 0.01), vegetable (ttrend = 3.72, P < 0.01) and fruit (ttrend = 3.17, P < 0.01) intakes for girls.

Conclusions/applications

Interventions designed to help adolescents improve consumption of fruits, vegetables and dairy foods may be enhanced by including a parental component aimed at increasing household availability and parents' intake of healthful food choices.
A regional food-frequency questionnaire for the US Mississippi Delta
Authors: Tucker Katherine L , Maras Janice , Champagne Catherine , Connell Carol , Goolsby Susan , Weber Judith , Zaghloul Sahar , Carithers Teresa , Bogle Margaret L
Published: February 2005

Objective

To describe food sources of nutrient intake for white and African American adults in the Lower Mississippi Delta (LMD), and their use in the development of a regional food-frequency questionnaire (FFQ) based on an earlier version of the National Cancer Institute's Health Habits and History Questionnaire.

Design

We ranked food sources of energy, macronutrients, vitamins and minerals, and examined portion size distributions for 842 white and 857 African American residents aged 19 years and older, using 24-hour dietary intake recall data from a telephone survey of 36 LMD counties. These values were used to develop a regional FFQ, which was then field-tested with 100 subjects and revised to improve interpretability.

Setting

The LMD region of the USA.

Subjects

White and African American adult residents of the LMD.

Results

LMD African Americans obtained more of their energy and nutrient intakes from poultry, processed meat, salty snacks, fruit drinks, pork and cornbread; and less from milk, alcohol, legumes, salad dressing, butter/margarine and sweetened tea than did white residents. Regional foods not on nationally used FFQs included grits, turnip greens, okra, ham hocks, chitterlings, crawfish, catfish, cracklings, jambalaya, potato logs, chicken and dumplings, and sweet potato pie. Based on responses during field-testing, the questionnaire was also designed to add four portion sizes for each food item, presented as questions, rather than in grid format.

Conclusions

Regional food use patterns differ from national patterns and furthermore differ between African American and white adults in the LMD. The resulting Delta NIRI FFQ for Adults should contribute to improved assessment of usual intake for use in studies of diet and health in this region.
Acceptability of multiple micronutrient supplements by pregnant and lactating women in Mali
Authors: Aguayo Víctor M , Koné Diakalia , Bamba Sory Ibrahim , Diallo Baba , Sidibé Yacouba , Traoré Diakalia , Signé Pierre , Baker Shawn K
Published: February 2005

Background

In Mali, an estimated 73% of pregnant women are anaemic largely due to iron deficiency. National policy recommends women to take iron and folic acid supplements daily from first prenatal contact until 3 months postpartum. However, many pregnant women in Mali could benefit from multiple micronutrient supplements.

Objective

To assess pregnant women's acceptability of and adherence to a daily multiple micronutrient supplementation scheme compared with the current daily iron and folic acid supplementation scheme.

Design

Seventy pregnant women were allocated to either the daily multiple micronutrient or daily iron and folic acid supplementation scheme. Women started receiving supplements at the end of the first trimester of pregnancy until delivery and throughout the first 3 months postpartum.

Results

No significant differences were observed between comparison groups with respect to women's perceptions about supplement size, colour, taste or flavour. Adherence to the multiple micronutrient supplementation scheme was better (257.5±20.9 tablets; average adherence 95.4%) than that to the iron and folic acid supplementation scheme (238.5±32.7 tablets; average adherence 92.2% P = 0.008) although both were very good, as were women's perceptions about the benefits of micronutrient supplements to their health and that of their newborns.

Conclusion

Malian women adhere to prenatal/postpartum micronutrient supplementation – no matter what supplement is chosen – when access to supplements is guaranteed and when they are provided with minimum, consistent and easily understandable information and counselling, indicating that these are key elements to ensure effective programmes. These findings, together with those of the global research agenda on the efficacy of multiple micronutrient supplements for pregnant women, will inform policy development in Mali for the effective control of iron deficiency and iron-deficiency anaemia in pregnant women.
DRhoGEF2 regulates actin organization and contractility in the Drosophila blastoderm embryo
Authors: Padash Barmchi Mojgan , Rogers Stephen , Häcker Udo
Published: February 2005

Morphogenesis of the Drosophila melanogaster embryo is associated with a dynamic reorganization of the actin cytoskeleton that is mediated by small GTPases of the Rho family. Often, Rho1 controls different aspects of cytoskeletal function in parallel, requiring a complex level of regulation. We show that the guanine triphosphate (GTP) exchange factor DRhoGEF2 is apically localized in epithelial cells throughout embryogenesis. We demonstrate that DRhoGEF2, which has previously been shown to regulate cell shape changes during gastrulation, recruits Rho1 to actin rings and regulates actin distribution and actomyosin contractility during nuclear divisions, pole cell formation, and cellularization of syncytial blastoderm embryos. We propose that DRhoGEF2 activity coordinates contractile actomyosin forces throughout morphogenesis in Drosophila by regulating the association of myosin with actin to form contractile cables. Our results support the hypothesis that specific aspects of Rho1 function are regulated by specific GTP exchange factors.
CDK4 regulation by TNFR1 and JNK is required for NF-κB–mediated epidermal growth control
Authors: Zhang Jennifer Y. , Tao Shiying , Kimmel Robin , Khavari Paul A.
Published: February 2005

Nuclear factor κB (NF-κB) mediates homeostatic growth inhibition in the epidermis, and a loss of NF-κB function promotes proliferation and oncogenesis. To identify mechanisms responsible for these effects, we impaired NF-κB action in the epidermis by three different genetic approaches, including conditional NF-κB blockade. In each case, epidermal hyperplasia was accompanied by an increase in both protein levels and tissue distribution of the G1 cell cycle kinase, CDK4. CDK4 up-regulation required intact TNFR1 and c-Jun NH2-terminal kinase (JNK) function. Cdk4 gene deletion concomitant with conditional NF-κB blockade demonstrated that CDK4 is required for growth deregulation. Therefore, epidermal homeostasis depends on antagonist regulation of CDK4 expression by NF-κB and TNFR1/JNK.
Regulation of T helper type 2 cell differentiation by murine Schnurri-2
Authors: Kimura Motoko Y. , Hosokawa Hiroyuki , Yamashita Masakatsu , Hasegawa Akihiro , Iwamura Chiaki , Watarai Hiroshi , Taniguchi Masaru , Takagi Tsuyoshi , Ishii Shunsuke , Nakayama Toshinori
Published: February 2005

Schnurri (Shn) is a large zinc finger protein implicated in cell growth, signal transduction, and lymphocyte development. Vertebrates possess at least three Shn orthologues (Shn-1, Shn-2, and Shn-3), which appear to act within the bone morphogenetic protein, transforming growth factor β, and activin signaling pathways. However, the physiological functions of the Shn proteins remain largely unknown. In Shn-2–deficient mice, mature peripheral T cells exhibited normal anti–T cell receptor–induced proliferation, although there was dramatic enhancement in the differentiation into T helper type (Th)2 cells and a marginal effect on Th1 cell differentiation. Shn-2–deficient developing Th2 cells showed constitutive activation of nuclear factor κB (NF-κB) and enhanced GATA3 induction. Shn-2 was able to compete with p50 NF-κB for binding to a consensus NF-κB motif and inhibit NF-κB–driven promoter activity. Thus, Shn-2 plays a crucial role in the control of Th2 cell differentiation by regulating NF-κB function.
RAGE limits regeneration after massive liver injury by coordinated suppression of TNF-α and NF-κB
Authors: Cataldegirmen Guellue , Zeng Shan , Feirt Nikki , Ippagunta Nikalesh , Dun Hao , Qu Wu , Lu Yan , Rong Ling Ling , Hofmann Marion A. , Kislinger Thomas , Pachydaki Sophia I. , Jenkins Daniel G. , Weinberg Alan , Lefkowitch Jay , Rogiers Xavier , Yan Shi Fang , Schmidt Ann Marie , Emond Jean C.
Published: February 2005

The exquisite ability of the liver to regenerate is finite. Identification of mechanisms that limit regeneration after massive injury holds the key to expanding the limits of liver transplantation and salvaging livers and hosts overwhelmed by carcinoma and toxic insults. Receptor for advanced glycation endproducts (RAGE) is up-regulated in liver remnants selectively after massive (85%) versus partial (70%) hepatectomy, principally in mononuclear phagocyte-derived dendritic cells (MPDDCs). Blockade of RAGE, using pharmacological antagonists or transgenic mice in which a signaling-deficient RAGE mutant is expressed in cells of mononuclear phagocyte lineage, significantly increases survival after massive liver resection. In the first hours after massive resection, remnants retrieved from RAGE-blocked mice displayed increased activated NF-κB, principally in hepatocytes, and enhanced expression of regeneration-promoting cytokines, TNF-α and IL-6, and the antiinflammatory cytokine, IL-10. Hepatocyte proliferation was increased by RAGE blockade, in parallel with significantly reduced apoptosis. These data highlight central roles for RAGE and MPDDCs in modulation of cell death–promoting mechanisms in massive hepatectomy and suggest that RAGE blockade is a novel strategy to promote regeneration in the massively injured liver.
The adaptor molecules LAT and SLP-76 are specifically targeted by Yersinia to inhibit T cell activation
Authors: Gerke Christiane , Falkow Stanley , Chien Yueh-hsiu
Published: February 2005

T cell responses are critical to the survival of Yersinia-infected animals. Yersinia have the ability to directly suppress T lymphocyte activation through the virulence factor YopH, a tyrosine phosphatase. Using single cell video microscopy and FACS analysis, here we show that even an average of one Yersinia per T cell is sufficient to inhibit or alter T cell responses. This efficient inhibition is traced to specific targeting by YopH of the adaptor proteins, linker for activation of T cells (LAT) and SH2-domain–containing leukocyte protein of 76 kD (SLP-76), which are crucial for T cell antigen receptor (TCR) signaling. A catalytically inactive YopH translocated via the type III secretory pathway from the bacteria into T cells primarily binds to LAT and SLP-76. Furthermore, among the proteins of the TCR signaling pathway, the tyrosine phosphorylation levels of LAT and SLP-76 are the most affected in T cells exposed to low numbers of Yersinia pseudotuberculosis. This is the first example showing that a pathogen targets these adaptor proteins in the TCR signaling pathway, suggesting a novel mechanism by which pathogens may efficiently alter T cell–mediated immune responses.
Peyton Rous
Authors: Van Epps Heather L.
Published: February 2005

In 1910, Peyton Rous identified a transmissible avian tumor virus, a discovery that began the journey from tumor virus biology to tumor biology itself.
Functional analysis of secA homologues from rickettsiae
Authors: Rahman M. Sayeedur , Simser Jason A. , Macaluso Kevin R. , Azad Abdu F.
Published: February 2005

The molecular basis of protein secretion that underlines rickettsial pathogenesis remains unknown. This paper reports the molecular and functional analysis of the putative secA gene, an essential component of the Sec-dependent protein secretion pathway, from Rickettsia rickettsii and Rickettsia typhi, the aetiological agents of Rocky Mountain spotted fever and murine typhus, respectively. The sequence analysis of the cloned secA genes from R. rickettsii and R. typhi show ORFs of 2721 and 2718 nt, respectively. Alignment of the deduced amino acid sequences reveals the presence of highly conserved amino acid residues and motifs considered to be essential for the ATPase activity of SecA in preprotein translocation. Transcription analysis indicates that R. rickettsii secA is expressed monocistronically from the canonical prokaryotic promoter, with a transcriptional start point located 32 nt upstream of the secA initiation codon. Complementation analysis shows that the full-length SecA protein from R. rickettsii and R. typhi fails to restore growth of the temperature-sensitive Escherichia coli strain MM52 secA51(ts) at a non-permissive temperature (42 °C), despite the detection of SecA protein expression by Western blotting. However, the chimeric SecA protein carrying the N-terminal 408 aa of R. rickettsii SecA fused with the C-terminal 480 aa of E. coli SecA restores the growth of E. coli strain MM52 secA51(ts) at the non-permissive temperature (42 °C). These results suggest that the N-terminal ATPase domain is highly conserved, whereas the C-terminal domain appears to be species specific.
Variation in gene expression patterns as the insect pathogen Metarhizium anisopliae adapts to different host cuticles or nutrient deprivation in vitro
Authors: Freimoser Florian M. , Hu Gang , Leger Raymond J. St
Published: February 2005

Metarhizium anisopliaeinfects a broad range of insects by direct penetration of the host cuticle. To explore the molecular basis of this process, its gene expression responses to diverse insect cuticles were surveyed, using cDNA microarrays constructed from an expressed sequence tag (EST) clone collection of 837 genes. During growth in culture containing caterpillar cuticle (Manduca sexta),M. anisopliaeupregulated 273 genes, representing a broad spectrum of biological functions, including cuticle-degradation (e.g. proteases), amino acid/peptide transport and transcription regulation. There were also many genes of unknown function. The 287 down-regulated genes were also distinctive, and included a large set of ribosomal protein genes. The response to nutrient deprivation partially overlapped with the response toMan. sextacuticle, but unique expression patterns in response to cuticles from another caterpillar (Lymantria dispar), a cockroach (Blaberus giganteus) and a beetle (Popilla japonica) indicate that the pathogen can respond in a precise and specialized way to specific conditions. The subtilisins provided an example of a large gene family in which differences in regulation could potentially allow virulence determinants to target different hosts and stages of infection. Comparisons betweenM. anisopliaeand published data onTrichoderma reeseiandSaccharomyces cerevisiaeidentified differences in the regulation of glycolysis-related genes and citric acid cycle/oxidative phosphorylation functions. In particular,M. anisopliaehas multiple forms of several catabolic enzymes that are differentially regulated in response to sugar levels. These may increase the flexibility ofM. anisopliaeas it responds to nutritional changes in its environment.
Maintenance of ΔpH by a butanol-tolerant mutant of Clostridium beijerinckii
Authors: Wang Fanqiang , Kashket Shelby , Kashket Eva R.
Published: February 2005

The isolation ofClostridium beijerinckiimutants that are more tolerant of butanol than the wild-type offered the opportunity to investigate whether the membrane activities which are required for maintaining the transmembrane ΔpH (the difference in pH between the cellular interior and exterior) are sensitive targets of butanol toxicity. The ΔpH was measured by the accumulation of [14C]benzoate using late-exponential-phase cells which were suspended in citrate/phosphate buffer at pH 5 (to maximize the ΔpH component of the protonmotive force) and supplemented with glucose and Mg2+. The ΔpH of the butanol-tolerant tolerant mutant, strain BR54, ofC. beijerinckiiNCIMB 8052 was found to be significantly more tolerant of added butanol than the wild-type. Thus, in potassium citrate/phosphate buffer the mutant cells maintained a ΔpH of 1·4 when butanol was added to a concentration of 1·5 % (w/v), while the wild-type ΔpH was reduced to 0·1. The ΔpH of both strains was completely dissipated with 1·75 % butanol, an effect attributed to a chaotropic effect on the membrane phospholipids. Similar results were obtained in sodium citrate/phosphate buffer. In the absence of added Mg2+, the ΔpH of the mutant decreased in both sodium and potassium citrate/phosphate buffer, but more rapidly in the former. Interestingly, the addition of butanol at low concentrations (0·8 %) prevented this ΔpH dissipation, but only in cells suspended in sodium citrate/phosphate buffer, and not in potassium citrate/phosphate buffer. In wild-type cells the decrease in ΔpH occurred more slowly than in the mutant, and sparing of the ΔpH by 0·8 % butanol was less pronounced. The authors interpret these data to mean that the ΔpH is dissipated in the absence of Mg2+by a Na+- or K+-linked process, possibly by a Na+/H+or a K+/H+antiporter, and that the former is inhibited by butanol. Apparently, butanol can selectively affect a membrane-associated function at concentrations lower than required for the complete dissipation of transmembrane ion gradients. Additionally, since the butanol-tolerant mutant BR54 is deficient in the ability to detoxify methylglyoxal (MG) and contains higher levels of MG than the wild-type, the higher Na+/H+antiporter activity of the mutant may be due to the greater degree of protein glycation by MG in the mutant cells. The mechanism of butanol tolerance may be an indirect result of the elevated glycation of cell proteins in the mutant strain. Analysis of membrane protein fractions revealed that mutant cells contained significantly lower levels of unmodified arginine residues than those of the wild-type cells, and that unmodified arginine residues of the wild-type were decreased by exposure of the growing cells to added MG.
Genetic and physiological analysis of the major OxyR-regulated katA from Xanthomonas campestris pv. phaseoli
Authors: Chauvatcharin Nopmanee , Atichartpongkul Sopapan , Utamapongchai Supa , Whangsuk Wirongrong , Vattanaviboon Paiboon , Mongkolsuk Skorn
Published: February 2005

katAencodes the major catalase that accounts for 90 % of the total catalase activity present inXanthomonas campestrispv.phaseoli.katAis located upstream of an ORF designatedankAencoding a cytoplasmic membrane protein homologous to eukaryotic ankyrin. Transcriptional analysis ofkatAandankAidentified twokatAtranscripts: a major monocistronickatAtranscript and a minor bicistronickatA–ankAtranscript. KatA expression was induced in the presence of various oxidants including H2O2, organic hydroperoxides and the superoxide-generating agent menadione, in an OxyR-dependent manner. Analysis of thekatApromoter region showed a putative OxyR binding site located upstream of anEscherichia coli-likeσ70−35 region that is likely to be responsible for transcription activation in response to oxidant treatment. Gel mobility shift experiments confirmed that purified OxyR specifically binds to thekatApromoter. AkatAmutant was highly sensitive to H2O2during both the exponential and stationary phases of growth. This phenotype could be complemented by functionalkatA, confirming the essential role of the gene in protectingX. campestrisfrom H2O2toxicity. Unexpectedly, inactivation ofankAalso significantly reduced resistance to H2O2and the phenotype could be complemented by plasmid-borne expression ofankA. Physiological analyses showed thatkatAplays an important role in, but is not solely responsible for, both the adaptive and menadione-induced cross-protective responses to H2O2killing inX. campestris.
Finite‐element modeling of dry sliding wear in metals
Authors: Molinari J.F. , Ortiz M. , Radovitzky R. , Repetto E.A.
Published: February 2005

This paper is concerned with the calibration and validation of a finite‐element model of dry sliding wear in metals. The model is formulated within a Lagrangian framework capable of accounting for large plastic deformations and history‐dependent material behavior. We resort to continuous adaptive meshing as a means of eliminating deformation‐induced element distortion, and of resolving fine features of the wear process such as contact boundary layers. Particular attention is devoted to a generalization of Archard’s law in which the hardness of the soft material is allowed to be a function of temperature. This dependence of hardness on temperature provides a means of capturing the observed experimental transition between severe wear rates at low speeds to mild wear rates at high speeds. Other features of the numerical model include: surface evolution due to wear; finite‐deformation J2 thermoplasticity; heat generation and diffusion in the bulk; non‐equilibrium heat‐transfer across the contact interface; and frictional contact. The model is validated against a conventional test configuration consisting of a brass pin rubbing against a rotating steel plate.
Speed accuracy of the modern industrial robot
Authors: Young Ken , Pickin Craig G.
Published: February 2005

Improvements in both robot manufacture and robot controller technology have resulted in greater robot accuracy. A trial has been conducted to highlight the improvements brought by this evolution. By measuring the accuracy of the velocity profiles of two generations of the Fanuc Hexapod robot (the Flextool), these evolutionary developments are illustrated. The results from the trial show that although both generations of robot exhibit good accuracy, the later robot is superior both in terms of mechanical design and in controller processing capability.
Robots carry the load at Scania
Authors: Kochan Anna
Published: February 2005

Outlines how Scania is planning to automate its truck axle production
lines at its Falun plant in Sweden. The automation package includes 40 PCs,
26 robots and 15 AGVs. The PCs are linked up to an Ethernet LAN which
connects to the factory management system. IBM’s Plantworks software
co‐ordinates the entire operation. Describes how the robots were
chosen and how they will operate on the production line. The new plant will
begin operating in August 1996 and will be required to function with a
utilization rate of 90–94 per cent.
Industrial robotics in South‐East Asia: ISIR Report
Authors: Shirinzadeh Bijan
Published: February 2005

Reports on the proceedings of the 26th ISIR (International Symposium on Industrial Robots) held in Singapore, October 1995 and on the 4th Asian‐Pacific Industrial Automation Exhibition (IA ’95) held in conjunction with it. Subjects included addressing robot technology to service jobs – a potentially greater marketing sector than manufacturing; the future of robotics in Asia; and robot technology for medium and small companies.