bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kalman interpolation filter for channel estimation of LTE downlink in high-mobility environments
Authors: Dai Xuewu , Zhang Wuxiong , Xu Jing , Mitchell John E , Yang Yang 
Published: July 2012

Abstract
The estimation of fast-fading LTE downlink channels in high-speed applications of LTE advanced is investigated in this article. In order to adequately track the fast time-varying channel response, an adaptive channel estimation and interpolation algorithm is essential. In this article, the multi-path fast-fading channel is modelled as a tapped-delay, discrete, finite impulse response filter, and the time-correlation of the channel taps is modelled as an autoregressive (AR) process. Using this AR time-correlation, we develop an extended Kalman filter to jointly estimate the complex-valued channel frequency response and the AR parameters from the transmission of known pilot symbols. Furthermore, the channel estimates at the known pilot symbols are interpolated to the unknown data symbols by using the estimated time-correlation. This article integrates both channel estimation at pilot symbols and interpolation at data symbol into the proposed Kalman interpolation filter. The bit error rate performance of our new channel estimation scheme is demonstrated via simulation examples for LTE and fast-fading channels in high-speed applications.
Coincidence and fixed points for contractions and cyclical contractions in partial metric spaces
Authors: Aydi Hassen , Vetro Calogero , Sintunavarat Wutiphol , Kumam Poom 
Published: July 2012

Abstract
We prove some coincidence and common fixed point results for three mappings satisfying a generalized weak contractive condition in ordered partial metric spaces. As application of the presented results, we give a unique fixed point result for a mapping satisfying a weak cyclical contractive condition. We also provide some illustrative examples.

MSC:47H10, 54H25.
Recurrent/moderate hypoglycemia induces hippocampal dendritic injury, microglial activation, and cognitive impairment in diabetic rats
Authors: Won Seok Joon , Yoo Byung Hoon , Kauppinen Tiina M , Choi Bo Young , Kim Jin Hee , Jang Bong Geom , Lee Min Woo , Sohn Min , Liu Jialing , Swanson Raymond A , Suh Sang Won 
Published: July 2012

AbstractBackgroundRecurrent/moderate (R/M) hypoglycemia is common in type 1 diabetes. Although mild or moderate hypoglycemia is not life-threatening, if recurrent, it may cause cognitive impairment. In the present study, we sought to determine whether R/M hypoglycemia leads to neuronal death, dendritic injury, or cognitive impairment.MethodsThe experiments were conducted in normal and in diabetic rats. Rats were subjected to moderate hypoglycemia by insulin without anesthesia. Oxidative stress was evaluated by 4-Hydroxy-2-nonenal immunostaining and neuronal death was determined by Fluoro-Jade B staining 7 days after R/M hypoglycemia. To test whether oxidative injury caused by NADPH oxidase activation, an NADPH oxidase inhibitor, apocynin, was used. Cognitive function was assessed by Barnes maze and open field tests at 6 weeks after R/M hypoglycemia.ResultsThe present study found that oxidative injury was detected in the dendritic area of the hippocampus after R/M hypoglycemia. Sparse neuronal death was found in the cortex, but no neuronal death was detected in the hippocampus. Significant cognitive impairment and thinning of the CA1 dendritic region was detected 6 weeks after hypoglycemia. Oxidative injury, cognitive impairment, and hippocampal thinning after R/M hypoglycemia were more severe in diabetic rats than in non-diabetic rats. Oxidative damage in the hippocampal CA1 dendritic area and microglial activation were reduced by the NADPH oxidase inhibitor, apocynin.ConclusionThe present study suggests that oxidative injury of the hippocampal CA1 dendritic region by R/M hypoglycemia is associated with chronic cognitive impairment in diabetic patients. The present study further suggests that NADPH oxidase inhibition may prevent R/M hypoglycemia-induced hippocampal dendritic injury.
Effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculation in endotoxinemic rats
Authors: Mihaylova Stanka , Killian Anke , Mayer Konstantin , Pullamsetti Soni Savai , Schermuly Ralph , Rosengarten Bernhard 
Published: July 2012

AbstractBackgroundIn sepsis syndromes the severity of the inflammation triggers microvascular dysfunction and early organ failure. We studied the effects of anti-inflammatory vagus nerve stimulation on the cerebral microcirculatory integrity in an endotoxinemic rat model.MethodsIn both control and endotoxinemic (5 mg/kg lipopolysaccharide i.v.) rats, the effect of cervical bilateral vagotomy with or without left-sided distal vagus nerve stimulation were compared to non-vagotomized, nonstimulated group (sham). Neurovascular coupling was analyzed by electrical forepaw stimulation, EEG, and cortical laser-Doppler flow recording. Resting cerebral blood flow, evoked potentials and hemodynamic responses, were obtained over a period of 4.5 hours. Regulation of the nitric oxide system (iNOS expression and nitrite/nitrate measurements), cytokines (IFN-γ, TNF-α, IL-6, IL-10), hypoxic and apoptosis signaling molecules (HIF-2α, Bax) were measured at the end of experiments.ResultsIn endotoxinemic rats, vagus nerve stimulation tended to increase anti-inflammatory cytokine levels and resulted in a stabile hemodynamic response (28 ± 13%; versus baseline). Vagotomized animals incurred a pro-inflammatory response (7 ± 4%;P < 0.0001 versus baseline) and produced more HIF-2α than vagotomized vagus nerve stimulated (VNS) animals. Evoked potential amplitudes were stabilized in VNS (15 ± 7 μV; n.s. versus baseline) as compared to vagotomised rats (8 ± 5 μV;P < 0.001 versus baseline). However, no effects were observed on apoptosis markers or nitric oxide levels.ConclusionsVagus nerve stimulation in endotoxinemic rats had a positive effect on neurovascular coupling and stabilized evoked potentials.
On the kinetics of anaerobic power
Authors: Moxnes John F , Hausken Kjell , Sandbakk Øyvind 
Published: July 2012

Abstract

Background
This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises.

Results
Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, Model 2 showed that the alactic energy storage decreased with time, whereas Model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy.

Conclusions
The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicate that blood lactate levels can be accurately modeled during steady state, and suggests a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power.
Glutamine supplementation in a child with inherited GS deficiency improves the clinical status and partially corrects the peripheral and central amino acid imbalance
Authors: Häberle Johannes , Shahbeck Noora , Ibrahim Khalid , Schmitt Bernhard , Scheer Ianina , O’Gorman Ruth , Chaudhry Farrukh A , Ben-Omran Tawfeg 
Published: July 2012

AbstractGlutamine synthetase (GS) is ubiquitously expressed in mammalian organisms and is a key enzyme in nitrogen metabolism. It is the only known enzyme capable of synthesising glutamine, an amino acid with many critical roles in the human organism. A defect inGLUL, encoding for GS, leads to congenital systemic glutamine deficiency and has been described in three patients with epileptic encephalopathy. There is no established treatment for this condition.Here, we describe a therapeutic trial consisting of enteral and parenteral glutamine supplementation in a four year old patient with GS deficiency. The patient received increasing doses of glutamine up to 1020 mg/kg/day. The effect of this glutamine supplementation was monitored clinically, biochemically, and by studies of the electroencephalogram (EEG) as well as by brain magnetic resonance imaging and spectroscopy.Treatment was well tolerated and clinical monitoring showed improved alertness. Concentrations of plasma glutamine normalized while levels in cerebrospinal fluid increased but remained below the lower reference range. The EEG showed clear improvement and spectroscopy revealed increasing concentrations of glutamine and glutamate in brain tissue. Concomitantly, there was no worsening of pre-existing chronic hyperammonemia.In conclusion, supplementation of glutamine is a safe therapeutic option for inherited GS deficiency since it corrects the peripheral biochemical phenotype and partially also improves the central biochemical phenotype. There was some clinical improvement but the patient had a long standing severe encephalopathy. Earlier supplementation with glutamine might have prevented some of the neuronal damage.
Measurement of multiple biomarkers in advanced stage heart failure patients treated with pulmonary artery catheter guided therapy
Authors: Zilinski Jodi L , Shah Ravi V , Gaggin Hanna K , Gantzer Mary Lou , Wang Thomas J , Januzzi James L 
Published: July 2012

Abstract
Introduction
This study was carried out to investigate the prognostic utility of biomarkers in advanced stage heart failure (HF) patients requiring ICU admission for pulmonary artery catheter (PAC) guided therapy.

Methods
Thirty patients admitted to an ICU for PAC guided HF therapy were enrolled; concentrations of soluble ST2 (sST2), highly sensitive troponin I, an experimental ultrasensitive troponin I, amino-terminal pro-B type natriuretic peptide, cystatin C, and myeloperoxidase were measured over the first 48 hours. Outcomes included response of filling pressures and hemodynamics to tailored therapy and 90-day event-free survival (death, left ventricular assist device implantation, transplant).

Results
Of the biomarkers evaluated, only sST2 concentrations were higher in those who failed to achieve goals for central venous pressure ((CVP), 225.3 versus 104.6 ng/mL; P = 0.003) and pulmonary capillary wedge pressure ((PCWP), 181.7 versus 88.2 ng/mL; P = 0.05). Only sST2 concentrations were associated with adverse events (186.7 versus 92.2 ng/mL; P = 0.01). In age-adjusted Cox proportional hazards analysis, an elevated sST2 during the first 48 hours following ICU admission independently predicted 90-day outcomes (Hazard Ratio = 5.53; P = 0.03) superior to the Simplified Acute Physiology Score for this application; in Kaplan-Meier analysis the risk associated with elevated sST2 concentrations was present early and sustained through the duration of follow-up (log rank P = 0.01).

Conclusions
In patients undergoing HF therapy guided by invasive monitoring, sST2 concentrations were associated with impending failure to reduce filling pressures and predicted impending events. Elevated sST2 values early in the ICU course theoretically could assist therapeutic decision-making in advanced stage HF patients.

Trial registration
ClinicalTrials.gov Identifier: NCT00595738
Staphylococcus epidermidis pan-genome sequence analysis reveals diversity of skin commensal and hospital infection-associated isolates
Authors: Conlan Sean , Mijares Lilia A ,   NISC Comparative Sequencing Program, Becker Jesse , Blakesley Robert W , Bouffard Gerard G , Brooks Shelise , Coleman Holly , Gupta Jyoti , Gurson Natalie , Park Morgan , Schmidt Brian , Thomas Pamela J , Otto Michael , Kong Heidi H , Murray Patrick R , Segre Julia A 
Published: July 2012

Abstract
Background
While Staphylococcus epidermidis is commonly isolated from healthy human skin, it is also the most frequent cause of nosocomial infections on indwelling medical devices. Despite its importance, few genome sequences existed and the most frequent hospital-associated lineage, ST2, had not been fully sequenced.

Results
We cultivated 71 commensal S. epidermidis isolates from 15 skin sites and compared them with 28 nosocomial isolates from venous catheters and blood cultures. We produced 21 commensal and 9 nosocomial draft genomes, and annotated and compared their gene content, phylogenetic relatedness and biochemical functions. The commensal strains had an open pan-genome with 80% core genes and 20% variable genes. The variable genome was characterized by an overabundance of transposable elements, transcription factors and transporters. Biochemical diversity, as assayed by antibiotic resistance and in vitro biofilm formation, demonstrated the varied phenotypic consequences of this genomic diversity. The nosocomial isolates exhibited both large-scale rearrangements and single-nucleotide variation. We showed that S. epidermidis genomes separate into two phylogenetic groups, one consisting only of commensals. The formate dehydrogenase gene, present only in commensals, is a discriminatory marker between the two groups.

Conclusions
Commensal skin S. epidermidis have an open pan-genome and show considerable diversity between isolates, even when derived from a single individual or body site. For ST2, the most common nosocomial lineage, we detect variation between three independent isolates sequenced. Finally, phylogenetic analyses revealed a previously unrecognized group of S. epidermidis strains characterized by reduced virulence and formate dehydrogenase, which we propose as a clinical molecular marker.
Developmental features of DNA methylation during activation of the embryonic zebrafish genome
Authors: Andersen Ingrid S , Reiner Andrew H , Aanes Håvard , Aleström Peter , Collas Philippe 
Published: July 2012

Abstract
Background
Zygotic genome activation (ZGA) occurs at the mid-blastula transition (MBT) in zebrafish and is a period of extensive chromatin remodeling. Genome-scale gametic demethylation and remethylation occurs after fertilization, during blastula stages, but how ZGA relates to promoter DNA methylation states is unknown. Using methylated DNA immunoprecipitation coupled to high-density microarray hybridization, we characterize genome-wide promoter DNA methylation dynamics before, during and after ZGA onset, in relation to changes in post-translational histone modifications and gene expression.

Results
We show methylation of thousands of promoters before ZGA and additional methylation after ZGA, finding more dynamic methylation -1 to 0 kb upstream of the transcription start site than downstream. The MBT is marked by differential methylation of high and low CpG promoters, and we identify hypomethylated promoters that are mostly CG-rich and remain hypomethylated through the MBT. Hypomethylated regions constitute a platform for H3K4me3, whereas H3K9me3 preferentially associates with methylated regions. H3K27me3 associates with either methylation state depending on its coincidence with H3K4me3 or H3K9me3. Cohorts of genes differentially expressed through the MBT period display distinct promoter methylation patterns related to CG content rather than transcriptional fate. Lastly, although a significant proportion of genes methylated in sperm are unmethylated in embryos, over 90% of genes methylated in embryos are also methylated in sperm.

Conclusions
Our results suggest a pre-patterning of developmental gene expression potential by a combination of DNA hypomethylation and H3K4 trimethylation on CG-rich promoters, and are consistent with a transmission of DNA methylation states from gametes to early embryos.
Median fin function during the escape response of bluegill sunfish (Lepomis macrochirus). II: Fin-ray curvature
Authors: Chadwell Brad A. , Standen Emily M. , Lauder George V. , Ashley-Ross Miriam A. 
Published: July 2012

SUMMARY
Although kinematic analysis of individual fin rays provides valuable insight into the contribution of median fins to C-start performance, it paints an incomplete picture of the complex movements and deformation of the flexible fin surface. To expand our analysis of median fin function during the escape response of bluegill sunfish (Lepomis macrochirus), patterns of spanwise and chordwise curvature of the soft dorsal and anal fin surfaces were examined from the same video sequences previously used in analysis of fin-ray movement and orientation. We found that both the span and chord undergo undulation, starting in the anterior region of either fin. Initiated early in Stage 1 of the C-start, the undulation travels in a postero-distal direction, reaching the trailing edge of the fins during early Stage 2. Maximum spanwise curvature typically occurred among the more flexible posterior fin rays, though there was no consistent correlation between maximum curvature and fin-ray position. Undulatory patterns suggest different mechanisms of action for the fin regions. In the anterior fin region, where the fin rays are oriented dorsoventrally, undulation is directed primarily chordwise, initiating a transfer of momentum into the water to overcome the inertia of the flow and direct the water posteriorly. Within the posterior region, where the fin rays are oriented caudally, undulation is predominantly directed spanwise; thus, the posterior fin region acts to ultimately accelerate this water towards the tail to increase thrust forces. Treatment of median fins as appendages with uniform properties does not do justice to their complexity and effectiveness as control surfaces.
Taste preference for amino acids is dependent on internal nutritional state inDrosophila melanogaster
Authors: Toshima Naoko , Tanimura Teiichi 
Published: July 2012

SUMMARYLike mammals, insects need to ingest proteins from foods because they cannot synthesise several amino acids. Amino acids are also essential nutrients for Drosophila melanogaster, especially for female egg production, but how flies detect amino acids and how the feeding response to amino acids is regulated are unknown. In this study, the two-choice preference test, the proboscis extension reflex test and a CAFE assay were performed to explore the ability of D. melanogaster to detect and discriminate amino acids. To determine whether D. melanogaster change their feeding preference to amino acids after being deprived of them, as previously reported in the locust, two groups of flies raised on the usual medium or on glucose medium were compared. Amino-acid-deprived flies demonstrated enhanced preference to an amino acid mixture and to several amino acids. These flies ingested amino acids even when they were replete with glucose. The proboscis extension reflex to particular amino acids was induced only in amino-acid-deprived flies. Our findings indicate that the sensitivity of labellar taste cells to amino acids may change when flies are deficient in amino acid supply, and also reveal that the detection pathways for individual amino acids may differ. We suggest the existence of an amino acid receptor and a monitoring system regulating the feeding responses to amino acids.
The dive response redefined: underwater behavior influences cardiac variability in freely diving dolphins
Authors: Noren Shawn R. , Kendall Traci , Cuccurullo Veronica , Williams Terrie M. 
Published: July 2012

SUMMARYA hallmark of the dive response, bradycardia, promotes the conservation of onboard oxygen stores and enables marine mammals to submerge for prolonged periods. A paradox exists when marine mammals are foraging underwater because activity should promote an elevation in heart rate (fH) to support increased metabolic demands. To assess the effect of the interaction between the diving response and underwater activity on fH, we integrated interbeat fH with behavioral observations of adult bottlenose dolphins diving and swimming along the coast of the Bahamas. As expected for the dive response, fH while resting during submergence (40±6 beats min−1) was significantly lower than fH while resting at the water surface (105±8 beats min−1). The maximum recorded fH (fH,max) was 128±7 beats min−1, and occurred during post-dive surface intervals. During submergence, the level of bradycardia was modified by activity. Behaviors such as simple head bobbing at depth increased fH by 40% from submerged resting levels. Higher heart rates were observed for horizontal swimming at depth. Indeed, the dolphins operated at 37–58% of their fH,max while active at depth and approached 57–79% of their fH,max during anticipatory tachycardia as the animals glided to the surface. fH was significantly correlated with stroke frequency (range=0–2.5 strokes s−1, r=0.88, N=25 dives) and calculated swim speed (range=0–5.4 m s−1, r=0.88, N=25 dives). We find that rather than a static reflex, the dive response is modulated by behavior and exercise in a predictable manner.
Measuring airborne components of seismic body vibrations in a Middle-Asian sand-dwelling Insectivora species, the piebald shrew (Diplomesodon pulchellum)
Authors: Volodin Ilya A. , Zaytseva Alexandra S. , Ilchenko Olga G. , Volodina Elena V. , Chebotareva Anastasia L. 
Published: July 2012

SUMMARY
Self-produced seismic vibrations have been found for some subterranean rodents but have not been reported for any Insectivora species, although seismic sensitivity has been confirmed for blind sand-dwelling chrysochlorid golden moles. Studying the vocal behaviour of captive piebald shrews, Diplomesodon pulchellum, we documented vibrations, apparently generated by the whole-body wall muscles, from 11 (5 male, 6 female) of 19 animals, placed singly on a drum membrane. The airborne waves of the vibratory drumming were digitally recorded and then analysed spectrographically. The mean frequency of vibration was 160.5 Hz. This frequency matched the periodicity of the deep sinusoidal frequency modulation (159.4 Hz) found in loud screech calls of the same subjects. The body vibration was not related to thermoregulation, hunger-related depletion of energy resources or fear, as it was produced by well-fed, calm animals, at warm ambient temperatures. We hypothesize that in the solitary, nocturnal, digging desert piebald shrew, body vibrations may be used for seismic exploration of substrate density, to avoid energy-costly digging of packed sand for burrowing and foraging. At the same time, the piercing quality of screech calls due to the deep sinusoidal frequency modulation, matching the periodicity of body vibration, may be important for agonistic communication in this species.