bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cross‐layer design for energy efficient communication in wireless sensor networks
Authors: Lin Xiao‐Hui , Kwok Yu‐Kwong , Wang Hui 
Published: February 2008

AbstractThere is a plethora of recent research on high performance wireless communications using a cross‐layer approach in that adaptive modulation and coding (AMC) schemes at wireless physical layer are used for combating time varying channel fading and enhance link throughput. However, in a wireless sensor network, transmitting packets over deep fading channel can incur excessive energy consumption due to the usage of stronger forwarding error code (FEC) or more robust modulation mode. To avoid such energy inefficient transmission, a straightforward approach is to temporarily buffer packets when the channel is in deep fading, until the channel quality recovers. Unfortunately, packet buffering may lead to communication latency and buffer overflow, which, in turn, can result in severe degradation in communication performance. Specifically, to improve the buffering approach, we need to address two challenging issues: (1) how long should we buffer the packets? and (2) how to choose the optimum channel transmission threshold above which to transmit the buffered packets? In this paper, by using discrete‐time queuing model, we analyze the effects of Rayleigh fading over AMC‐based communications in a wireless sensor network. We then analytically derive the packet delivery rate and average delay. Guided by these numerical results, we can determine the most energy‐efficient operation modes under different transmission environments. Extensive simulation results have validated the analytical results, and indicates that under these modes, we can achieve as much as 40% reduction in energy dissipation. Copyright © 2008 John Wiley & Sons, Ltd.
Involvement of PPARα in the growth inhibitory effect of arachidonic acid on breast cancer cells
Authors: Bocca Claudia , Bozzo Francesca , Martinasso Germana , Canuto Rosa Angela , Miglietta Antonella 
Published: February 2008

Epidemiological studies suggest that dietary PUFA may influence breast cancer progression.n-3 PUFA are generally known to exert antitumour effects, whereas reports relative ton-6 PUFA anti-carcinogen effects are controversial. Arachidonic acid (AA; 20 : 4n − 6) and its metabolites have been shown to inhibit the growth of human breast cancer cell lines, even if the downstream mechanisms by which AA may influence carcinogenesis remain unresolved. We explored the molecular basis for AA influence on proliferation, signal transduction and apoptosis in two human breast cancer cell lines, MCF-7 and MDA-MB-231. In both cell lines AA inhibited cell growth in a dose-dependent manner, even if MDA-MB-231 was somewhat more growth-inhibited than MCF-7. AA decreased extracellular signal-regulated protein kinase 1/2 phosphorylation level, and positively modulated PPARγ and PPARα expression, with only a slight effect against PPARβ/δ. In addition, AA increased Bak (an apoptosis-regulating protein) expression and reduced procaspase-3 and -9 levels only in MDA-MB-231 cells, thus indicating that the growth inhibitory effect can be correlated with apoptosis induction. In both cell lines the use of a specific antagonist made it possible to establish a relationship between AA growth inhibitory effect and PPARα involvement. AA decreases cell proliferation most likely by inducing apoptosis in MDA-MB-231 cells, while in the MCF-7 cell line the growth inhibitory activity can be attributed to the inhibition of the signal transduction pathway involved in cell proliferation. In both cases, the results here presented suggest PPARα as a possible contributor to the growth inhibitory effect of AA.
How Much Can a Victor Force the Vanquished to Pay? France under the Nazi Boot
Authors: OCCHINO FILIPPO , OOSTERLINCK KIM , WHITE EUGENE N. 
Published: February 2008

Occupation charges paid by France to Nazi Germany represent one of the largest international transfers and contributed significantly to the German war effort. We employ a neoclassical growth model that incorporates essential features of the occupied economy to assess the welfare costs of the policies that managed the payments to Germany. Our lower bound estimates show that occupation payments required a severe cut in consumption. A draft of labor to Germany and a reduction of real wages added to this burden. Management of the accumulated domestic debt required large budget surpluses; but post-Liberation inflation slashed the real debt.“Ils ne nous ont rien enlevé de vive force; ils ont toujours tout acheté correctement; mais ils nous ont tout payé avec de l'argent qu'ils nous avaient volé.”1
Escherichia colitranscription factor YncC (McbR) regulates colanic acid and biofilm formation by repressing expression of periplasmic protein YbiM (McbA)
Authors: Zhang Xue-Song , García-Contreras Rodolfo , Wood Thomas K 
Published: February 2008

AbstractQuorum-sensing signal autoinducer 2 (AI-2) stimulates Escherichia coli biofilm formation through the motility regulator MqsR that induces expression of the putative transcription factor encoded by yncC. Here, we show that YncC increases biofilm formation by repressing overproduction of the exopolysaccharide identified as colanic acid (corroborated by decreasing mucoidy and increased sensitivity to bacteriophage P1 infection). Differential gene expression and gel shift assays demonstrated that YncC is a repressor of the predicted periplasmic protein-encoding gene, ybiM, which was corroborated by the isogenic yncC ybiM double mutation that repressed the yncC phenotypes (biofilm formation, colanic acid overproduction, mucoidy and bacteriophage resistance). Through nickel-enrichment DNA microarrays and additional gel shift assays, we found that the putative transcription factor B3023 (directly upstream of mqsR) binds the yncC promoter. Overexpressing MqsR, AI-2 import regulators LsrR/LsrK and AI-2 exporter TqsA induced yncC transcription, whereas the AI-2 synthase LuxS and B3023 repressed yncC. MqsR has a toxic effect on E. coli bacterial growth, which is partially reduced by the b3023 mutation. Therefore, AI-2 quorum-sensing control of biofilm formation is mediated through regulator MqsR that induces expression of the transcription factor YncC. YncC inhibits the expression of periplasmic YbiM, which prevents overproduction of colanic acid (excess colanic acid causes mucoidy) and prevents YbiM from inhibiting biofilm formation.
Substrate-induced growth and isolation of Acidobacteria from acidic Sphagnum peat
Authors: Pankratov Timofei A , Serkebaeva Yulia M , Kulichevskaya Irina S , Liesack Werner , Dedysh Svetlana N 
Published: February 2008

Abstract
Fluorescence in situ hybridization (FISH) was applied to estimate the population size of the poorly characterized phylum Acidobacteria in acidic peat sampled from nine different Sphagnum-dominated wetlands of Northern Russia. The cell numbers of these bacteria in oxic peat layers ranged from 0.4 × 106 to 1.3 × 107 cells per g of wet peat, comprising up to 4% of total bacterial cells. Substrate-induced growth of acidobacteria was observed after amendment of peat samples with glucose, pectin, xylan, starch, ethanol and methanol, while weak or no response was obtained for acetate, pyruvate, mannitol and cellobiose. Using low-nutrient media and FISH-mediated monitoring of the isolation procedure, we succeeded in obtaining nine strains of acidobacteria in pure cultures. These strains belonged to subdivisions 1 and 3 of the Acidobacteria and represented strictly aerobic, heterotrophic organisms. Except for methanol, the substrate utilization patterns of these isolates matched the results obtained in our substrate-amendment experiments with native peat. All strains were also capable of utilizing galacturonic acid, a characteristic component of the cell wall in Sphagnum spp, which is released during moss decomposition. Most isolates from subdivision 1 were truly acidophilic organisms with the growth optimum at pH 3.5–4.5, while the isolates from subdivision 3 grew optimally at pH 5.5–6.5. Another important phenotypic trait of novel strains was their capability of active growth at low temperatures. Both acidophily and low-temperature growth are consistent with the occurrence of acidobacteria in cold and acidic northern wetlands.
Effects of Gastric Electric Stimulation on Gastric Distention Responsive Neurons and Expressions of CCK in Rodent Hippocampus
Authors: Xu Luo , Sun Xiangrong , Lu Jiang , Tang Ming , Chen J.D.Z. 
Published: February 2008

Objective: Gastric electrical stimulation (GES) has been introduced for treating obesity. The hippocampus is known to be involved in the regulation of gastrointestinal motility. Changes in hypathalumus cholecystokinin (CCK) have been observed in genetically obese rodents. This experiment was to study the effect of GES on the activities of neurons and the expression of CCK in the hippocampus.Methods and Procedures: We investigated the effect of GES (GES‐I: pulse train of standard parameters; GES‐2: reduced train‐on time; GES‐3: increased pulse width; GES‐4: reduced pulse frequency) on neurons responsive to gastric distention (GD) by recording extracellular potentials of single neurons and observing the expression of CCK in the rodent hippocampus by immunohistochemistry staining, radioimmunoassay, and real‐time PCR.Results: 92.1% of neurons in the CA2‐3 region responded to GD, 53.2% of which showed excitation (GD‐E), and 46.8% showed inhibition (GD‐I). 64.8% GD‐responsive neurons were excited by GES. The response was associated with stimulation strength, pulse width, and frequency; 70.6, 57.1, 94.4, and 66.7% of GD‐E and 72.7, 57.1, 86.4, and 50% of GD‐I neurons showed excitatory responses to GES‐I, −2, −3, and −4, respectively. CCK immunoreactive positive neurons (P < 0.001), the content of CCK‐like materials (P < 0.05) and the amount of CCK mRNA were significantly increased after GES (P < 0.05).Discussion: These findings suggest the central, neuronal, and hormonal mechanisms of GES. GES may excite the activity of GD‐sensitive neurons and increase the expression of CCK in the hippocampus. These excitatory effects of GES seem to be related to the parameters of stimulation.
Serum levels of immunoglobulin E and the subsequent risk of pre‐eclampsia: a population‐based study
Authors: ESKILD ANNE , IL NILSEN TOM , JEANSSON STIG , JENUM PÅL A. , VATTEN LARS J. 
Published: February 2008

AbstractObjective. Women with allergy may be at increased risk of developing preeclampsia. We assessed serum levels of immunoglobulin E (IgE) in the first and second trimester, and changes in concentration between trimesters, in relation to risk of preeclampsia. Materials and Methods. Population based case‐control study within a cohort of 29,948 pregnant women. We included 154 preeclampsia cases with preterm delivery (before week 37) and 190 cases with delivery at term. As controls, 392 women without preeclampsia were randomly selected. Levels of IgE were in sera from the first and second trimester were measured and women who later developed preeclampsia were compared to controls with respect to IgE levels. Results. Comparing the highest to the lowest quartile of IgE in the first trimester, the odds ratio for preterm preeclampsia was 1.7 (95% CI, 0.9–3.1), and in the second trimester, the odds ratio was 1.5 (95% CI, 0.8–2.9) for the highest compared to the lowest quartile of IgE. Change in IgE between trimesters was not associated with preeclampsia risk. Conclusion. There was a weak, however, not significant association between high levels of IgE in the first and second trimester and subsequent risk of preterm preeclampsia.
Spectral analysis of fetal heart rate variability for fetal surveillance: review of the literature
Authors: VAN LAAR J.O.E.H. , PORATH M.M. , PETERS C.H.L. , OEI S.G. 
Published: February 2008

AbstractBackground. Cardiotocography has a poor diagnostic value in detecting fetal acidosis. Spectral analysis of fetal heart rate variability can be used to monitor the fetal autonomic nervous system. Objective. To determine the value of spectral analysis for fetal surveillance. Methods. A systematic search was performed in the electronic databases CENTRAL (the Cochrane Library; 2007, Issue 3), PUBMED and EMBASE up to May 2007. Articles that described spectral analysis of human fetal heart rate variability and compared the energy in spectral bands with blood‐gas values obtained by funipuncture or from the umbilical cord immediately postpartum were included. Results. Six studies met the inclusion criteria. The included studies were heterogeneous, various methods of spectral analysis and different frequency bands were used and the outcome measures varied. Five out of six studies showed a decrease in spectral energy in the low frequency (LF) band in case of fetal distress. An extremely low LF power had a sensitivity of 97.5% and a specificity of 86.1% to detect fetal distress. Conclusions. Spectral analysis could be a promising method for fetal surveillance. Larger prospective studies are needed to determine the exact diagnostic value of spectral analysis. For further research, standardisation of spectral analysis is recommended. Studies should focus on real time monitoring.
Midwives’ and obstetricians’ knowledge and management of women presenting with decreased fetal movements
Authors: HEAZELL ALEXANDER E.P. , GREEN MATTHEW , WRIGHT CAROLINE , FLENADY VICKI , FREDERIK FRØEN J. 
Published: February 2008

AbstractBackground. Maternal perception of decreased fetal movements (DFM) affects 5–15% of pregnancies. DFM is associated with intra‐uterine fetal death (IUFD) and intra‐uterine growth restriction (IUGR). It has been proposed that maternal perception of DFM may be used as a screening tool for IUFD or IUGR. However, this proposal is complicated by variations in definitions and management of DFM. Hypothesis. We hypothesised that uncertainties in the definition and management of women presenting with DFM leads to variation in clinical practice. Methods. A postal questionnaire was sent to midwives and consultant obstetricians in the UK. Results. The majority of respondents enquired about the presence of fetal movements after 28 weeks gestation. There was little agreement on a definition of DFM, with a maternal perception of decreased movements for 24 h gaining the greatest acceptance. Few practitioners used formal fetal movement counting, with the majority of respondents stating they were ineffective in the prevention of IUGR or IUFD and led to increased intervention. There was large variation in the knowledge of associations with DFM and management of women presenting with DFM. Conclusions. There were wide variations in the practice of obstetricians and midwives with regard to women presenting with DFM; many aspects of practice were not based on the available evidence. The variation in practice may result from a lack of robust evidence on which to base the provision of care. Further research is needed to provide and disseminate evidence to direct the management of women presenting with DFM.
Advance provision of emergency contraceptive pills reduces treatment delay: a randomised controlled trial among Swedish teenage girls
Authors: EKSTRAND MARIA , LARSSON MARGARETA , DARJ ELISABETH , TYDÉN TANJA 
Published: February 2008

AbstractObjective. To evaluate an intervention involving advance provision of emergency contraceptive pills (ECP) to Swedish teenage girls. Material and methods. Some 420 girls aged 15–19, requesting ECP at a local youth clinic were randomly assigned to intervention group (IG) (n = 214) or control group (CG) (n = 206). Both groups received ECP on request. The IG received one extra dose of ECP, condoms and an information leaflet regarding ECP and condom use. Main outcome measures were differences between IG and CG regarding ECP use, time span between unprotected intercourse and ECP intake, contraceptive use, and sexual risk taking. Questionnaires were completed at the initial visit, and the girls were followed up by structured telephone interviews 3 and 6 months later. Results. At the 3‐month follow‐up, girls in the IG were almost twice as likely to have used ECP compared to girls in the CG (IG: 24.0%, CG: 13%, p = 0.02), and they used it sooner after unprotected intercourse (mean time IG: 13.61 h, CG: 25.47 h, p = 0.007). Significant differences persisted 6 months after the intervention (ECP use IG: 31%, CG: 19%, p = 0.01; and mean time IG: 15.59 h, CG: 26.38 h, p = 0.006). No significant differences were found in the use of regular hormonal contraceptives or condoms at either follow‐up. About 40% of the girls in both groups had risked pregnancy during the follow‐up period, but only half of these had used ECP. Conclusions. This intervention shortened the time interval from unprotected intercourse to pill intake without jeopardising contraceptive use and without increasing sexual risk taking.
A Multicenter Qualitative Study on Preventing Hospital-Acquired Urinary Tract Infection in US Hospitals
Authors: Saint Sanjay , Kowalski Christine P. , Forman Jane , Damschroder Laura , Hofer Timothy P. , Kaufman Samuel R. , Creswell John W. , Krein Sarah L. 
Published: February 2008

Objective.Although urinary tract infection (UTI) is the most common hospital-acquired infection, there is little information about why hospitals use or do not use a range of available preventive practices. We thus conducted a multicenter study to understand better how US hospitals approach the prevention of hospital-acquired UTI.Methods.This research is part of a larger study employing both quantitative and qualitative methods. The qualitative phase consisted of 38 semistructured phone interviews with key personnel at 14 purposefully sampled US hospitals and 39 in-person interviews at 5 of those 14 hospitals, to identify recurrent and unifying themes that characterize how hospitals have addressed hospital-acquired UTI.Results.Four recurrent themes emerged from our study data. First, although preventing hospital-acquired UTI was a low priority for most hospitals, there was substantial recognition of the value of early removal of a urinary catheter for patients. Second, those hospitals that made UTI prevention a high priority also focused on noninfectious complications and had committed advocates, or “champions,” who facilitated prevention activities. Third, hospital-specific pilot studies were important in deciding whether or not to use devices such as antimicrobial-impregnated catheters. Finally, external forces, such as public reporting, influenced UTI surveillance and infection prevention activities.Conclusions.Clinicians and policy makers can use our findings to develop initiatives that, for example, use a champion to promote the removal of unnecessary urinary catheters or exploit external forces, such public reporting, to enhance patient safety.
The Gene for the P-Subunit of Glycine Decarboxylase from the C4 SpeciesFlaveria trinervia: Analysis of Transcriptional Control in TransgenicFlaveria bidentis(C4) and Arabidopsis (C3)
Authors: Engelmann Sascha , Wiludda Christian , Burscheidt Janet , Gowik Udo , Schlue Ute , Koczor Maria , Streubel Monika , Cossu Roberto , Bauwe Hermann , Westhoff Peter 
Published: February 2008

AbstractGlycine decarboxylase (GDC) plays an important role in the photorespiratory metabolism of plants. GDC is composed of four subunits (P, H, L, and T) with the P-subunit (GLDP) serving as the actual decarboxylating unit. In C3 plants, GDC can be found in all photosynthetic cells, whereas in leaves of C3-C4 intermediate and C4 species its occurrence is restricted to bundle-sheath cells. The specific expression of GLDP in bundle-sheath cells might have constituted a biochemical starting point for the evolution of C4 photosynthesis. To understand the molecular mechanisms responsible for restricting GLDP expression to bundle-sheath cells, we performed a functional analysis of the GLDPA promoter from the C4 species Flaveria trinervia. Expression of a promoter-reporter gene fusion in transgenic plants of the transformable C4 species Flaveria bidentis (C4) showed that 1,571 bp of the GLDPA 5′ flanking region contain all the necessary information for the specific expression in bundle-sheath cells and vascular bundles. Interestingly, we found that the GLDPA promoter of F. trinervia exhibits a C4-like spatial activity also in the C3 plant Arabidopsis (Arabidopsis thaliana), indicating that a mechanism for bundle-sheath-specific expression is also present in this C3 species. Using transgenic Arabidopsis, promoter deletion studies identified two regions in the GLDPA promoter, one conferring repression of gene expression in mesophyll cells and one functioning as a general transcriptional enhancer. Subsequent analyses in transgenic F. bidentis confirmed that these two segments fulfill the same function also in the C4 context.
Sequence Variation of MicroRNAs and Their Binding Sites in Arabidopsis
Authors: Ehrenreich Ian M. , Purugganan Michael D. 
Published: February 2008

Abstract
Major differences exist between plants and animals both in the extent of microRNA (miRNA)-based gene regulation and the sequence complementarity requirements for miRNA-messenger RNA pairing. Whether these differences affect how these sites evolve at the molecular level is unknown. To determine the extent of sequence variation at miRNAs and their targets in a plant species, we resequenced 16 miRNA families (66 miRNAs in total) and all 52 of the characterized binding sites for these miRNAs in the plant model Arabidopsis (Arabidopsis thaliana), accounting for around 50% of the known miRNAs and binding sites in this species. As has been shown previously in humans, we find that both miRNAs and their target binding sites have very low nucleotide variation and divergence compared to their flanking sequences in Arabidopsis, indicating strong purifying selection on these sites in this species. Sequence data flanking the mature miRNAs, however, exhibit normal levels of polymorphism for the accessions in this study and, in some cases, nonneutral evolution or subtle effects on predicted pre-miRNA secondary structure, suggesting that there is raw material for the differential function of miRNA alleles. Overall, our results show that despite differences in the architecture of miRNA-based regulation, miRNAs and their targets are similarly constrained in both plants and animals.
Side chain burial and hydrophobic core packing in protein folding transition states
Authors: Farber Patrick J. , Mittermaier Anthony 
Published: February 2008

AbstractA critical step in the folding pathway of globular proteins is the formation of a tightly packed hydrophobic core. Several mutational studies have addressed the question of whether tight packing interactions are present during the rate‐limiting step of folding. In some of these investigations, substituted side chains have been assumed to form native‐like interactions in the transition state when the folding rates of mutant proteins correlate with their native‐state stabilities. Alternatively, it has been argued that side chains participate in nonspecific hydrophobic collapse when the folding rates of mutant proteins correlate with side‐chain hydrophobicity. In a reanalysis of published data, we have found that folding rates often correlate similarly well, or poorly, with both native‐state stability and side‐chain hydrophobicity, and it is therefore not possible to select an appropriate transition state model based on these one‐parameter correlations. We show that this ambiguity can be resolved using a two‐parameter model in which side chain burial and the formation of all other native‐like interactions can occur asynchronously. Notably, the model agrees well with experimental data, even for positions where the one‐parameter correlations are poor. We find that many side chains experience a previously unrecognized type of transition state environment in which specific, native‐like interactions are formed, but hydrophobic burial dominates. Implications of these results to the design and analysis of protein folding studies are discussed.