bluuebunny/crossref_metadata_2025 huggingface dataset:
A Mathematical Model of the Circadian Phase-Shifting Effects of Exogenous Melatonin
Authors: Breslow Emily R. , Phillips Andrew J.K. , Huang Jean M. , St. Hilaire Melissa A. , Klerman Elizabeth B.
Published: February 2013

Melatonin is endogenously produced and released in humans during nighttime darkness and is suppressed by ocular light exposure. Exogenous melatonin is used to induce circadian phase shifts and sleep. The circadian phase-shifting ability of a stimulus (e.g., melatonin or light) relative to its timing may be displayed as a phase response curve (PRC). Published PRCs to exogenous melatonin show a transition from phase advances to delays approximately 1 h after dim light melatonin onset. A previously developed mathematical model simulates endogenous production and clearance of melatonin as a function of circadian phase, light-induced suppression, and resetting of circadian phase by light. We extend this model to include the pharmacokinetics of oral exogenous melatonin and phase-shifting effects via melatonin receptors in the suprachiasmatic nucleus of the mammalian hypothalamus. Model parameters are fit using 2 data sets: (1) blood melatonin concentration following a 0.3- or 5.0-mg dose, and (2) a PRC to a 3.0-mg dose of melatonin. After fitting to the 3.0-mg PRC, the model correctly predicts that, by comparison, the 0.5-mg PRC is slightly decreased in amplitude and shifted to a later circadian phase. This model also reproduces blood concentration profiles of various melatonin preparations that differ only in absorption rate and percentage degradation by first-pass hepatic metabolism. This model can simulate experimental protocols using oral melatonin, with potential application to guide dose size and timing to optimally shift and entrain circadian rhythms.
Wavelet Meets Actogram
Authors: Leise Tanya L. , Indic Premananda , Paul Matthew J. , Schwartz William J.
Published: February 2013

A variety of methods to determine phase markers and period length from experimental data sets have traditionally assumed a rhythm of fixed period and amplitude. But most biological oscillations exhibit fluctuations in both period and amplitude, leading to the recent interest in the application of wavelet transforms that can measure how rhythms vary over time. Here we examine how wavelet-based methods can be extended to the analysis of conventional actograms, including the detection of onsets in circadian activity and temperature rhythms of rodents.
Odor Is a Time Cue for Circadian Behavior
Authors: Abraham U. , Saleh M. , Kramer A.
Published: February 2013

Many physiological and behavioral processes such as sleep and wakefulness, hormone secretion, and olfactory sensitivity exhibit a 24-h rhythmicity that persists in constant conditions with a period close to (circa) 24 h. These circadian rhythms are driven by a network of endogenous clocks residing in various tissues, including the olfactory system, and are synchronized to the outside world by environmental time cues such as light, temperature, and food. In addition to having these well-known zeitgebers of circadian clocks, most environments consist of a multitude of odors that report, for example, the availability of food or the presence of predators—and often, they do so in a time-of-day-dependent manner. Considering the evolutionary significance of odors for various fitness-related behaviors such as mate choice, predator avoidance, and foraging strategies, we asked whether odors—similar to light, temperature, or food—might act as a circadian time cue able to influence circadian locomotor behavior in mammals. Administering individual air flow, periodically saturated with an artificial odor mix, to running wheel-equipped mouse cages, we found that rhythmic odor administrations significantly lengthened the period of circadian activity rhythms. Additionally, odor cues led to partial reemergence of circadian locomotor rhythmicity in suprachiasmatic nuclei (SCN)–lesioned mice, suggesting that the SCN as the central circadian pacemaker are not immediately required for odor-mediated effects on circadian behavior. However, odor-based modulation of circadian behavior did not occur in clock mutant ( cry1−/−/ cry2−/−) mice, indicating an odor-mediated mechanism that involves extra-SCN canonical clocks, such as the olfactory clock itself. Our results indicate not only that odor stimuli can act as a circadian time cue modulating circadian behavior but also that odor effects are even more pronounced in the absence of the SCN but nevertheless require the presence of a functional canonical clock.
Modeling the Effects of the Circadian Clock on Cardiac Electrophysiology
Authors: Fotiadis Panagiotis , Forger Daniel B.
Published: February 2013

An internal circadian clock regulates the electrical activity of cardiac myocytes controlling the expression of potassium channel interacting protein–2 (KChIP2), which is a key regulator of cardiac electrical activity. Here, we examine how the circadian rhythm of KChIP2 expression affects the dynamics of human and murine ventricular action potentials (APs), as well as the intervals in the equivalent electrocardiograms (ECGs) reflecting the duration of depolarization and repolarization phases of the cardiac ventricular APs (QRS and QT intervals), with mathematical modeling. We show how the internal circadian clock can control the shape of APs and, in particular, predict AP, QRS, and QT interval prolongation following KChIP2 downregulation, as well as shortening of AP, QRS, and QT interval duration following KChIP2 upregulation. Based on the circadian expression of KChIP2, we can accurately predict the circadian rhythm in cardiac electrical activity and suggest the transient outward potassium currents as the key current for circadian rhythmicity. Our modeling work predicts a smaller effect of KChIP2 on AP and QT interval dynamics in humans. Taken together, these results support the role of KChIP2 as the key regulator of circadian rhythms in the electrical activity of the heart; we provide computational models that can be used to explore circadian rhythms in cardiac electrophysiology and susceptibility to arrhythmia.
Invisible discrimination
Authors: Pate Richard L
Published: February 2013

With the advent and popularity of social networking sites, the boundaries of the relationship between the employer and employee/prospective employee have stretched well beyond the workplace and working hours. Predictably, this relationship expansion has led to uncharted adversarial scenarios between the respective parties. Unfortunately, in this new, vibrant cyber world, employment law is struggling for deference and attention. Notwithstanding this ostensible indifference, each phase of the relationship is heavily impacted by social network media. Applicant recruitment, information gathering and applicant selection stand to be impacted by the social network communications made by employees or prospective employees. This article examines whether present and proposed law protects job applicants from potential, unlawful discrimination resulting from the employer’s use of social media in its applicant recruitment, information-gathering and applicant selection processes.
Generalized Dunkl-Williams inequality in 2-inner product spaces
Authors: Najati Abbas , Saem M Mohammadi , Bae Jae-Hyeong
Published: February 2013

We consider the generalized Dunkl-Williams inequality in 2-normed spaces. Also, we give necessary and sufficient conditions for having the equality case in the strictly convex 2-normed space X.
Multilocus sequence analysis of Treponema denticolastrains of diverse origin
Authors: Mo Sisu , You Meng , Su Yvonne CF , Lacap-Bugler Donnabella C , Huo Yong-biao , Smith Gavin JD , Leung W Keung , Watt Rory M
Published: February 2013

Background

The oral spirochete bacterium Treponema denticola is associated with both the incidence and severity of periodontal disease. Although the biological or phenotypic properties of a significant number of T. denticola isolates have been reported in the literature, their genetic diversity or phylogeny has never been systematically investigated. Here, we describe a multilocus sequence analysis (MLSA) of 20 of the most highly studied reference strains and clinical isolates of T. denticola; which were originally isolated from subgingival plaque samples taken from subjects from China, Japan, the Netherlands, Canada and the USA.

Results

The sequences of the 16S ribosomal RNA gene, and 7 conserved protein-encoding genes (flaA, recA, pyrH, ppnK, dnaN, era and radC) were successfully determined for each strain. Sequence data was analyzed using a variety of bioinformatic and phylogenetic software tools. We found no evidence of positive selection or DNA recombination within the protein-encoding genes, where levels of intraspecific sequence polymorphism varied from 18.8% (flaA) to 8.9% (dnaN). Phylogenetic analysis of the concatenated protein-encoding gene sequence data (ca. 6,513 nucleotides for each strain) using Bayesian and maximum likelihood approaches indicated that the T. denticola strains were monophyletic, and formed 6 well-defined clades. All analyzed T. denticola strains appeared to have a genetic origin distinct from that of ‘Treponema vincentii’ or Treponema pallidum. No specific geographical relationships could be established; but several strains isolated from different continents appear to be closely related at the genetic level.

Conclusions

Our analyses indicate that previous biological and biophysical investigations have predominantly focused on a subset of T. denticola strains with a relatively narrow range of genetic diversity. Our methodology and results establish a genetic framework for the discrimination and phylogenetic analysis of T. denticola isolates, which will greatly assist future biological and epidemiological investigations involving this putative ‘periodontopathogen’.
Cloning and characterization of two Argonaute genes in wheat (Triticum aestivum L.)
Authors: Meng Fanrong , Jia Haiying , Ling Na , Xue Yinlei , Liu Hao , Wang Ketao , Yin Jun , Li Yongchun
Published: February 2013

Background

Argonaute proteins are key components of RNA interference (RNAi), playing important roles in RNA-directed gene silencing. Various classes of Argonaute genes have been identified from plants and might be involved in developmental regulation. However, little is known about these genes in wheat (Triticum aestivum).

Results

In this study, two full-length cDNAs of Argonaute were cloned from wheat, designated as TaAGO1b and TaAGO4. The cDNA of TaAGO1b is 3273 bp long and encodes 868 amino acids, with a predicted molecular weight of ~97.78 kDa and pI of 9.29. The 3157-bp TaAGO4 encodes 916 amino acids, with a molecular mass of 102.10 kDa and pI of 9.12. Genomics analysis showed that TaAGO1b and TaAGO4 contain 20 and 18 introns, respectively. Protein structural analysis demonstrated that typical PAZ and PIWI domains were found in both TaAGO1b and TaAGO4. From the highly conserved PIWI domains, we detected conserved Asp-Asp-His (DDH) motifs that function as a catalytic triad and have critical roles during the process of sequence-specific cleavage in the RNAi machinery. Structural modelling indicated that both TaAGOs can fold to a specific α/β structure. Moreover, the three aligned DDH residues are spatially close to each other at the “slicer” site of the PIWI domain. Expression analysis indicated that both genes are ubiquitously expressed in vegetative and reproductive organs, including the root, stem, leaf, anther, ovule, and seed. However, they are differentially expressed in germinating endosperm tissues. We were interested to learn that the two TaAGOs are also differentially expressed in developing wheat plants and that their expression patterns are variously affected by vernalization treatment. Further investigation revealed that they can be induced by cold accumulation during vernalization.

Conclusions

Two putative wheat Argonaute genes, TaAGO1b and TaAGO4, were cloned. Phylogenetic analysis, prediction of conserved domains and catalytic motifs, and modelling of their protein structures suggested that they encode functional Argonaute proteins. Temporal and spatial expression analyses indicated that these genes are potentially involved in developmental regulation of wheat plants.
Safety and efficacy of high-dose daptomycin as salvage therapy for severe gram-positive bacterial sepsis in hospitalized adult patients
Authors: Lai Chung-Chih , Sheng Wang-Huei , Wang Jann-Tay , Cheng Aristine , Chuang Yu-Chung , Chen Yee-Chun , Chang Shan-Chwen
Published: February 2013

Background

Increasing the dosage of daptomycin may be advantageous in severe infection by enhancing bactericidal activity and pharmacodynamics. However, clinical data on using daptomycin at doses above 6 mg/kg in Asian population are limited.

Methods

A retrospective observational cohort study of all hospitalized adult patients treated with daptomycin (> 6 mg/kg) for at least 72 hours was performed in Taiwan.

Results

A total of 67 patients (40 males) with a median age of 57 years received a median dose of 7.61 mg/kg (range, 6.03-11.53 mg/kg) of daptomycin for a median duration of 14 days (range, 3–53 days). Forty-one patients (61.2%) were in intensive care units (ICU). Sites of infections included complicated skin and soft tissue infections (n = 16), catheter-related bacteremia (n = 16), endocarditis (n = 11), primary bacteremia (n = 10), osteomyelitis and septic arthritis (n = 9), and miscellaneous (n = 5). The median Pitt bacteremia score among the 54 (80.6%) patients with bacteremia was 4. The most common pathogen was methicillin-resistant Staphylococcus aureus (n = 38). Fifty-nine patients (88.1%) were treated with daptomycin after glycopepetide use. Overall, 52 (77.6%) patients achieved clinical success. The all-cause mortality rate at 28 day was 35.8%. In multivariate analysis, the significant predictors of in-hospital mortality in 54 bacteremic patients were malignancies (P = 0.01) and ICU stay (P = 0.02). Adverse effects of daptomycin were generally well-tolerated, leading to discontinuation in 3 patients. Daptomycin-related creatine phosphokinase (CPK) elevations were observed in 4 patients, and all received doses > 8 mg/kg.

Conclusions

Treatment with high dose daptomycin as salvage therapy was generally effective and safe in Taiwan. CPK level elevations were more frequent in patients with dose > 8 mg/kg.
Lanthanum carbonate for the treatment of hyperphosphatemia in CKD 5D: multicenter, double blind, randomized, controlled trial in mainland China
Authors: Xu Jing , Zhang Yi-Xiang , Yu Xue-Qing , Liu Zhi-Hong , Wang Li-Ning , Chen Jiang-Hua , Fan Ya-Ping , Ni Zhao-Hui , Wang Mei , Yuan Fa-Huan , Ding Guo-Hua , Chen Xiang-Mei , Zhang Ai-Ping , Mei Chang-Lin
Published: February 2013

Background

Serum phosphorus control is critical for chronic kidney disease (CKD) 5D patients. Currently, clinical profile for an oral phosphorus binder in the mainland Chinese population is not available.

Objective

To establish the efficacy, safety, and tolerability of lanthanum carbonate in CKD 5D patients.

Design

Multicenter, randomized, double blind, placebo-controlled study. A central randomization center used computer generated tables to allocate treatments.

Setting

Twelve tertiary teaching hospitals and medical university affiliated hospitals in mainland China.

Participants

Overall, 258 hemodialysis or continuous ambulatory peritoneal dialysis (CAPD) adult patients were enrolled.

Intervention

After a 0–3-week washout period and a 4-week lanthanum carbonate dose-titration period, 230 patients were randomized 1:1 to receive lanthanum carbonate (1500 mg-3000 mg) or placebo for a further 4-week maintenance phase.

Main outcome measures

Efficacy and safety of lanthanum carbonate to achieve and maintain target serum phosphorus concentrations were assessed.

Results

In the titration phase, serum phosphorus concentrations of all patients decreased significantly. About three-fifths achieved target levels without significantly disturbing serum calcium levels. At the end of the maintenance period, the mean difference in serum phosphorus was significantly different between the lanthanum carbonate and placebo-treated groups (0.63±0.62 mmol/L vs. 0.15±0.52 mmol/L, P < 0.001). The drug-related adverse effects were mild and mostly gastrointestinal in nature.

Conclusion

Lanthanum carbonate is an efficacious and well-tolerated oral phosphate binder with a mild AE profile in hemodialysis and CAPD patients. This agent may provide an alternative for the treatment of hyperphosphatemia in CKD 5D patients in mainland China.

Trial registration

No. ChiCTR-TRC-10000817
Neonatal outcomes after preterm birth by mothers’ health insurance status at birth: a retrospective cohort study
Authors: Einarsdóttir Kristjana , Haggar Fatima A , Langridge Amanda T , Gunnell Anthony S , Leonard Helen , Stanley Fiona J
Published: February 2013

Background

Publicly insured women usually have a different demographic background to privately insured women, which is related to poor neonatal outcomes after birth. Given the difference in nature and risk of preterm versus term births, it would be important to compare adverse neonatal outcomes after preterm birth between these groups of women after eliminating the demographic differences between the groups.

Methods

The study population included 3085 publicly insured and 3380 privately insured, singleton, preterm deliveries (32–36 weeks gestation) from Western Australia during 1998–2008. From the study population, 1016 publicly insured women were matched with 1016 privately insured women according to the propensity score of maternal demographic characteristics and pre-existing medical conditions. Neonatal outcomes were compared in the propensity score matched cohorts using conditional log-binomial regression, adjusted for antenatal risk factors. Outcomes included Apgar scores less than 7 at five minutes after birth, time until establishment of unassisted breathing (>1 minute), neonatal resuscitation (endotracheal intubation or external cardiac massage) and admission to a neonatal special care unit.

Results

Compared with infants of privately insured women, infants of publicly insured women were more likely to receive a low Apgar score (ARR = 2.63, 95% CI = 1.06-6.52) and take longer to establish unassisted breathing (ARR = 1.61, 95% CI = 1.25-2.07), yet, they were less likely to be admitted to a special care unit (ARR = 0.84, 95% CI = 0.80-0.87). No significant differences were evident in neonatal resuscitation between the groups (ARR = 1.20, 95% CI = 0.54-2.67).

Conclusions

The underlying reasons for the lower rate of special care admissions in infants of publicly insured women compared with privately insured women despite the higher rate of low Apgar scores is yet to be determined. Future research is warranted in order to clarify the meaning of our findings for future obstetric care and whether more equitable use of paediatric services should be recommended.
Explaining the amount of care needed by hospitalised surgical patients: a prospective time and motion study
Authors: van Oostveen Catharina J , Vermeulen Hester , Gouma Dirk J , Bakker Piet J , Ubbink Dirk T
Published: February 2013

Background

Hospitals provide care for patients with a variety of diseases, co-morbidities and complications. The actual amount of care these patients need is unclear. Given the recent developments such as ageing, multi-morbidity and budgetary restraints, a practical explanatory model would avail healthcare professionals and managers in determining the demand and costs for clinical care.

Methods

Six surgical wards in a Dutch university hospital participated in this prospective time and motion study. Surgeons, nurses and paramedics recorded the time spent on patient care 24/7 by means of PDAs. The investigators extracted possible determining characteristics from a previous systematic review and expert focus group. Total amount of care needed by the patients was expressed as costs involved in medical and nursing time, surgical interventions and diagnostics. Afterwards the investigators applied linear regression analysis to detect significant independent characteristics.

Results

174 Surgical patients were monitored during their hospital stay. Characteristics significantly influencing the consumed amount of care were: medication during hospitalisation, complications, co-morbidity, medical specialty, age, as well as undergoing surgery and length of stay. Median costs for care were €8.446 per patient admission.

Conclusions

The investigators developed a model that explains the total demand and costs of care needed for surgical patients in a university hospital. The input for this instrument can be derived from readily available data in hospital databases. This makes it a relatively easy instrument to help healthcare professionals and managers appreciate the amount of care needed on (surgical) wards and may be used to appreciate trends in time.
Validation of a new classifier for the automated analysis of the human epidermal growth factor receptor 2 (HER2) gene amplification in breast cancer specimens
Authors: Furrer Daniela , Jacob Simon , Caron Chantal , Sanschagrin François , Provencher Louise , Diorio Caroline
Published: February 2013

Amplification of the human epidermal growth factor receptor 2 (HER2) is a prognostic marker for poor clinical outcome and a predictive marker for therapeutic response to targeted therapies in breast cancer patients. With the introduction of anti-HER2 therapies, accurate assessment of HER2 status has become essential. Fluorescence in situ hybridization (FISH) is a widely used technique for the determination of HER2 status in breast cancer. However, the manual signal enumeration is time-consuming. Therefore, several companies like MetaSystem have developed automated image analysis software. Some of these signal enumeration software employ the so called “tile-sampling classifier”, a programming algorithm through which the software quantifies fluorescent signals in images on the basis of square tiles of fixed dimensions. Considering that the size of tile does not always correspond to the size of a single tumor cell nucleus, some users argue that this analysis method might not completely reflect the biology of cells. For that reason, MetaSystems has developed a new classifier which is able to recognize nuclei within tissue sections in order to determine the HER2 amplification status on nuclei basis. We call this new programming algorithm “nuclei-sampling classifier”. In this study, we evaluated the accuracy of the “nuclei-sampling classifier” in determining HER2 gene amplification by FISH in nuclei of breast cancer cells. To this aim, we randomly selected from our cohort 64 breast cancer specimens (32 nonamplified and 32 amplified) and we compared results obtained through manual scoring and through this new classifier. The new classifier automatically recognized individual nuclei. The automated analysis was followed by an optional human correction, during which the user interacted with the software in order to improve the selection of cell nuclei automatically selected. Overall concordance between manual scoring and automated nuclei-sampling analysis was 98.4% (100% for nonamplified cases and 96.9% for amplified cases). However, after human correction, concordance between the two methods was 100%. We conclude that the nuclei-based classifier is a new available tool for automated quantitative HER2 FISH signals analysis in nuclei in breast cancer specimen and it can be used for clinical purposes.
In vivo functional brain mapping in a conditional mouse model of human tauopathy (taup301l) reveals reduced neural activity in memory formation structures
Authors: Perez Pablo D , Hall Gabrielle , Kimura Tetsuya , Ren Yan , Bailey Rachel M , Lewis Jada , Febo Marcelo , Sahara Naruhiko
Published: February 2013

Background

Tauopathies are characterized by intracellular deposition of the microtubule-associated protein tau as filamentous aggregates. The rTg4510 mouse conditionally expresses mutant human tau protein in various forebrain areas under the Tet-off expression system. Mice develop neurofibrillary tangles, with significant neuronal loss and cognitive deficits by 6 months of age. Previous behavioral and biochemical work has linked the expression and aggregates of mutant tau to functional impairments. The present work used manganese-enhanced magnetic resonance imaging (MEMRI) to investigate basal levels of brain activity in the rTg4510 and control mice.

Results

Our results show an unmistakable curtailment of neural activity in the amygdala and hippocampus, two regions known for their role in memory formation, but not the cortex, cerebellum, striatum and hypothalamus in tau expressing mice.

Conclusion

Behavioral impairments associated with changes in activity in these areas may correspond to age progressive mutant tauP301L-induced neurodegeneration.
Suitability of endogenous reference genes for gene expression studies with human intraocular endothelial cells
Authors: Wei Ruoxin , Stewart Elizabeth Anne , Amoaku Winfried M
Published: February 2013

Background

The use of quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) has become widely applied as a method to measure transcript abundance. In order to be reflective of biological processes during health and disease this method is dependent on normalisation of data against stable endogenous controls. However, these genes can vary in their stability in different cell types. The importance of reference gene validation for a particular cell type is now well recognised and is an important step in any gene expression study.

Results

Cultured primary human choroidal and retinal endothelial cells were treated with the immunostimulant polyinosinic: polycytidylic acid or untreated. qRT-PCR was used to quantify the expression levels of 10 commonly used endogenous control genes, TBP, HPRT1, GAPDH, GUSB, PPIA, RPLP0, B2M, 18S rRNA, PGK1 and ACTB. Three different mathematical algorithms, GeNorm, NormFinder, and BestKeeper were used to analyse gene stability to give the most representative validation. In choroidal endothelial cells the most stable genes were ranked as HPRT1 and GUSB by GeNorm and NormFinder and HPRT1 and PPIA by BestKeeper. In retinal endothelial cells the most stable genes ranked were TBP and PGK1 by GeNorm and NormFinder and HPRT1 by BestKeeper. The least stable gene for both cell types was 18S with all 3 algorithms.

Conclusions

We have identified the most stable endogenous control genes in intraocular endothelial cells. It is suggested future qRT-PCR studies using these cells would benefit from adopting the genes identified in this study as the most appropriate endogenous control genes.
Automated identification of changes in electrode contact properties for long-term permanent ERT monitoring experiments
Authors: Deceuster John , Kaufmann Olivier , Van Camp Michel
Published: February 2013

Electrical resistivity tomography (ERT) monitoring experiments are being conducted more often to image spatiotemporal changes in soil properties. When conducting long-term ERT monitoring, the identification of suspicious electrodes in a permanent spread is of major importance because changes in electrode contact properties of a single electrode may affect the quality of many measurements on each time-slice. An automated methodology was developed to detect these temporal changes in electrode contact properties, based on a Bayesian approach called “weights of evidence.” Contrasts [Formula: see text] and studentized contrasts [Formula: see text] are estimators of the influence of each electrode in the global data quality. A consolidated studentized contrast [Formula: see text] is introduced to consider the proportion of rejected quadripoles which contain a single electrode. These estimators are computed for each time-slice using [Formula: see text]-factor (coefficient of variation of repeated measurements) threshold values, from 0 to 10%, to discriminate between selected and rejected quadripoles. An automated detection strategy is proposed to identify suspicious electrodes by comparing the [Formula: see text] to the [Formula: see text] (maximum expected [Formula: see text] values when every electrode is good for the given data set). These [Formula: see text] are computed using Monte-Carlo simulations of a hundred random draws where the distribution of [Formula: see text]-factor values follows a Weibull cumulative distribution, with [Formula: see text] and [Formula: see text], fitted on a background data set filtered using a 5% threshold on absolute reciprocal errors. The efficiency of the methodology and its sensitivity to the selected reciprocal error threshold are assessed on synthetic and field data. Our approach is suitable to detect suspicious electrodes and slowly changing conditions affecting the galvanic contact resistances where classical approaches are shown to be inadequate except when the faulty electrode is disconnected. A data-weighting method is finally proposed to ensure that only good data will be used in the inversion of ERT monitoring data sets.
Imaging above an extended-reach horizontal well using converted shear waves and a rig source
Authors: Haldorsen Jakob B. U. , Leaney W. Scott , Coates Richard T. , Petersen Steen A. , Rutledal Helge Ivar , Festervoll Kjetil A.
Published: February 2013

We evaluated a method for using 3C vertical seismic profile data to image acoustic interfaces located between the surface source and a downhole receiver array. The approach was based on simple concepts adapted from whole-earth seismology, in which observed compressional and shear wavefields are traced back to a common origin. However, unlike whole-earth and passive seismology, in which physical sources are imaged, we used the observed compressional and shear wavefields to image secondary sources (scatterers) situated between the surface source and the downhole receiver array. The algorithm consisted of the following steps: first, estimating the receiver compressional wavefield; second, using polarization to estimating the shear wavefield; third, deconvolving the shear wavefield using estimates of the source wavelet obtained from the direct compressional wave; fourth, the compressional and shear wavefields were back projected into the volume between the source and receivers; where, finally, an imaging condition was applied. When applied to rig-source VSP data acquired in an extended-reach horizontal well, this process was demonstrated to give images of formation features in the overburden, consistent with surface-seismic images obtained from the same area.
Efficient Laplace-domain full waveform inversion using a cyclic shot subsampling method
Authors: Ha Wansoo , Shin Changsoo
Published: February 2013

Full waveform inversion is a method used to recover subsurface parameters, and it requires heavy computational resources. We present a cyclic shot subsampling method to make the full waveform inversion efficient while maintaining the quality of the inversion results. The cyclic method subsamples the shots at a regular interval and changes the shot subset at each iteration step. Using this method, we can suppress the aliasing noise present in regular-interval subsampling. We compared the cyclic method with divide-and-conquer, random, and random-in-each-subgroup subsampling methods using the Laplace-domain full waveform inversion. We found examples of a 2D marine field data set from the Gulf of Mexico and a 3D synthetic salt velocity model. In the inversion examples using the subsampling methods, we could reduce the computation time and obtain results comparable to that without a subsampling technique. The cyclic method and two random subsampling methods yielded similar results; however, the cyclic method generated the best results, especially when the number of shot subsamples was small, as expected. We also examined the effect of subsample updating frequency. The updating frequency does not have a significant effect on the results when the number of subsamples is large. In contrast, frequent subsample updating becomes important when the number of subsamples is small. The random-in-each-subgroup scheme showed the best results if we did not update the subsamples frequently, while the cyclic method suffers from aliasing. The results suggested that the cyclic subsampling scheme can be an alternative to the random schemes and the distributed subsampling schemes with a frequently changing subset are better than lumped subsampling schemes.
Deep-water subsurface imaging using OBS interferometry
Authors: Carrière Olivier , Gerstoft Peter
Published: February 2013

Seismic interferometry processing is applied to an active seismic survey collected on ocean bottom seismometers (OBS) deployed at 900-m water depth over a carbonate/hydrates mound in the Gulf of Mexico. Common midpoint processing and stacking of the extracted Green’s function gives the subsurface PP reflectivity, with a horizontal resolution of half the receiver spacing. The obtained seismic section is comparable to classical upgoing/downgoing wavefield decomposition and deconvolution applied on a common receiver gather. Seismic interferometry does not require precise knowledge of source geometry or shooting times, but more accurate results are obtained when including this information for segmenting the signals before the crosscorrelations, especially when signals from distant surveys are present in the data. Reflectivity estimates can be obtained with the crosscorrelation of pressure or vertical particle velocity signals, but the pressure data gives the best resolution due to the wider frequency bandwidth and the reduced amount of noise bursts.
Test-site calibration and validation of airborne and ground-based TEM systems
Authors: Foged Nikolaj , Auken Esben , Christiansen Anders Vest , Sørensen Kurt Ingvard
Published: February 2013

Validation and calibration of airborne and ground-based time-domain electromagnetic (TEM) systems are important to obtain high-quality data and thereby reliable and reproducible results. Validation and calibration become even more important when the TEM systems are to be used for low-anomaly groundwater and environmental applications. The recent extension of the Danish TEM test site has made it possible to perform detailed validation of airborne TEM systems and calibrate airborne TEM systems that cannot make hovering measurements. We evaluated the Danish TEM test site and used a test site calibration scheme recommended for ground-based as well as airborne TEM systems. Furthermore, we discovered an extended data set from the airborne TEM system, SkyTEM, from the test site, used for an extensive validation of the SkyTEM system. This validation included repeatability tests at different heights and comparisons with the reference sections obtained with ground-based measurements. The validation and comparison were performed directly on the inversion results and in data space, down to the single data gate values. The extensive validation of the SkyTEM system at the TEM test site revealed a very stable and reliable system. The data repeatability of the SkyTEM system at different heights and directions was, in general, well within the standard deviation (STD) of the data. The agreement between the ground-based reference model sections and the SkyTEM model section from different recording heights was very good. Likewise, the match between the ground-based reference data and the SkyTEM data was good and, in general, within 1.5 times the STD on the data. The positive outcome of the extensive validation also confirmed that data processing and modeling were performed at the highest standard.
Inhibition of endocannabinoid degradation in experimental endotoxemia reduces leukocyte adhesion and improves capillary perfusion in the gut
Authors: Kianian Mandana , Al-Banna Nadia A. , Kelly Melanie E.M. , Lehmann Christian
Published: February 2013

Background: Changes in leukocyte-endothelial and microvascular perfusion are hallmark events in inflammation. Thus, protection of the intestinal microcirculation represents a pivotal therapeutic target in systemic inflammation and sepsis. The endocannabinoid system (ECS) modulates a number of critical homeostatic functions and has been associated with anti-inflammatory responses. Our study aimed to examine intestinal leukocyte adhesion and capillary perfusion following selective inhibition of the endocannabinoid degradation enzyme, fatty acid amide hydrolase (FAAH), in experimental sepsis (endotoxemia).

Methods: Five groups of rats were used: controls, endotoxemia [lipopolysaccharide (LPS)], FAAH inhibitor URB597 (0.3 mg/kg)+LPS, URB597 (0.6 mg/kg)+LPS, and URB597 (0.6 mg/kg)+cannabinoid 2 receptor (CB2R) antagonist (AM630)+LPS. After 2 h, intravital microscopy was performed to quantify intestinal leukocyte recruitment and functional capillary density (FCD), as well as macrohemodynamic monitoring and histological examinations.

Results: LPS induced a significant increase in leukocyte adhesion in collecting and postcapillary submucosal venules and a decrease in intestinal FCD. URB597 pretreatment prevented the LPS-induced increase in leukocyte adhesion in intestinal venules and a decrease in intestinal FCD. The administration of the CB2R inhibitor, AM630, with URB597 reversed the protective effects of URB597 on the LPS-induced increase in leukocyte adhesion in intestinal venules, but not URB597’s effect on the intestinal FCD.

Conclusions: FAAH inhibition prevents the LPS-induced increase in leukocyte adhesion and improves the capillary perfusion of the gut. This might be mediated in part by CB2R activation. Our study encourages further investigation into the therapeutic potential of drugs targeting the ECS in sepsis.
Nanotechnology Reviews
Authors: Grossmann Alexander , Sora Karin
Published: February 2013

No abstract available.
Ear skin optical clearing for improving blood flow imaging/Optisches Clearing der Ohrhaut zur verbesserten Bildgebung des Blutflusses
Authors: Wang Jing , Shi Rui , Zhang Yang , Zhu Dan
Published: February 2013

Various optical imaging techniques have shown a great potential for monitoring angiogenesis, development of blood vessels, and even tumor transfer, but they suffer from the limited imaging depth in tissue. Although the mouse ear provides an available window, the residual scattering of ear skin still influences the imaging quality. The proposed tissue optical clearing technique presents a new opportunity to decrease the scattering of skin, and enhance the imaging contrast or imaging depth of optical methods. The purpose of this study is to develop an innovative ear skin optical clearing agent (ESOCA) for improving the transparency of the mouse ear.

The ESOCA was topically applied on the ear skin of BALB/c mice

The transmittance of mice ear was enhanced by 111.0±8.2% at 633 nm after application of ESOCA. The cutaneous blood vessels and blood flow could be distinguished more clearly with LSCI technique. In addition, the calculated CNR values of speckle contrast images showed a great enhancement compared with the initial (control) values.

In summary, topical application of an innovative ESOCA permits the vessel structure and flow distribution information of cutaneous blood vessels to be imaged by LSCI with higher contrast, which will be significant for tumor studies in the future.
Occupational Sun Protection: Workplace Culture, Equipment Provision and Outdoor Workers' Characteristics
Authors: Reeder Anthony I. , Gray Andrew , Mccool Judith P.
Published: February 2013

Occupational Sun Protection: Workplace Culture, Equipment Provision and Outdoor Workers' Characteristics: Anthony I. REEDER, et al. Cancer Society of New Zealand Social and Behavioral Research Unit, Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, New Zealand—

Objectives

The aim of this study was to describe outdoor workers' sun‐protective practices, workplace sun‐safety culture and sun‐protective equipment provision; investigate the association of demographic, personal and occupational factors with sun‐protective practices; and identify potential strategies for improving workers' sun protection.

Methods

The present study used a clustered survey design with randomly identified employers in nine occupations. Employees provided questionnaire measures of demographics, personal characteristics (skin type, skin cancer risk perceptions, tanning attitudes, sun‐exposure knowledge), personal occupational sun protection practices (exposure reduction, use of sun‐protective clothing, sunscreen and shade), workplace sun‐protective equipment provision and perceived workplace sun‐safety culture. Summative scores were calculated for attitudes, knowledge, work place provision and culture. Amultivariable model was built with worker and workplace variables as plausible predictors of personal sun protection.

Results

In this study, 1,061 workers (69% participation) from 112 workplaces provided sufficient information for analysis. Sex, age, prioritized ethnicity, education and risk perception differed significantly between occupational groups (p<0.001), as did workers' sun‐protective practices and workplace sun‐protection equipment provision and supportive culture. After adjustment, each one‐point increase in Workplace Sun‐safety Culture Score (range 12 points) was associated with a 0.16 higher Personal Sun‐Protection Score (p<0.001), and each one‐point increase in Workplace Provision Score (range 4 points) was associated with a 0.14 higher score (p<0.001). Sun Protection Score was significantly associated with skin response to sun exposure (p<0.001), female sex (p=0.021), tanning attitudes (p=0.022) and occupation (p=0.049), but not ethnicity, age education, knowledge or skin cancer risk perception.

Conclusions

Protective equipment provision and sun‐protective workplace culture are promising components for the development of comprehensive programmes to improve outdoor workers' sun‐protective practices.
The role of Ross procedure in the management of congenital heart defects
Authors: Hartyánszky István , Kollár András , Kádár Krisztina , Ablonczy László , Novák Edit , Tóth Attila
Published: February 2013

Introduction: The surgical strategy to manage multilevel left ventricular outflow tract diseases is changing constantly, however, the Ross-procedure has remained a standard method for 45 years. Aim: The aim of the study was to analyze early and mid-term results of Ross-procedure in congenital heart defects (single surgeon’s results). Methods: From 2001 until 2011 a total of 63 patients (age, 28 days–21 years; mean: 10 years, weight 3.4–96 kg; mean, 8.8 kg) underwent Ross (n = 40), Ross–Konno (n = 17) or Ross–Konno-mitral (n = 6) procedures. Indication for Ross procedure was aortic regurgitation in 15 patients (associated with ventricular septum defect in 8 patients) and a predominant aortic stenosis in 25 patients. 17 patients with severe left ventricular outflow tract obstruction underwent Ross–Konno procedure. 6 patients with concomitant mitral valve disease (Shone syndrome, 3 patients; complete atrioventricular septal defect, 3 patients) were reconstructed by Ross–Konno-mitral valve procedure. Results: Among Ross patients there were one early (cerebral complication) and one late death (homograft endocarditis) with a mean follow-up time of 7.4±1.8 years. Because of an early autograft endocarditis a 3-year-old boy underwent homograft implantation and was treated successfully with Bentall-procedure 9 years later. One patient with autograft regurgitation is waiting for reoperation. Among Ross–Konno patients there was no early or late death, and none of the patients underwent reoperation. In Ross–Konno-mitral patients there was one early death (28-day-old boy) and during a mean follow-up time of 2.5±1 years, and no reintervention or reoperation was needed in 5 patients. Conclusions: The results indicate a good outcome of Ross-, Ross–Konno-, Ross–Konno-mitral procedures in patients with congenital heart defects when surgery is performed by a highly experienced heart surgeon. In newborns, infants and small children Ross- and Ross–Konno procedures are the only methods for managing left ventricular outflow tract diseases. Concomitant severe mitral disease adds a high level of technical complexity to the Ross–Konno/mitral procedure, but it should be balanced against alternative strategies (eg. single ventricle palliation or transplantation). Orv. Hetil., 2013, 154, 219–224.
Mapping the margin: comparing marginal values of tropical forest remnants for pollination services
Authors: Ricketts Taylor H. , Lonsdorf Eric
Published: February 2013

Natural ecosystems benefit human communities by providing ecosystem services such as water purification and crop pollination. Mapping ecosystem service values has become popular, but most are static snapshots of average value. Estimating instead the economic impacts of specific ecosystem changes can better inform typical resource decisions. Here we develop an approach to mapping marginal values, those resulting from the next unit of ecosystem change, across landscapes. We demonstrate the approach with a recent model of crop pollination services in Costa Rica, simulating deforestation events to predict resulting marginal changes in pollination services to coffee farms. We find that marginal losses from deforestation vary from zero to US$700/ha across the landscape. Financial risks for farmers from these losses and marginal benefits of forest restoration show similar spatial variation. Marginal values are concentrated in relatively few forest parcels not identified using average value. These parcels lack substitutes: nearby forest parcels that can supply services in the event of loss. Indeed, the marginal value of forest parcels declines exponentially with the density of surrounding forest cover. The approach we develop is applicable to any ecosystem service. Combined with information on costs, it can help target conservation or restoration efforts to optimize benefits to people and biodiversity.
Electrochemical methods for corrosion testing of Ce-based coating prepared on AA6060 alloy by dip immersion method
Authors: Jegdic Bore , Zivkovic Ljiljana , Popic Jovan , Bajat Jelena , Miskovic-Stankovic Vesna
Published: February 2013

Dip-immersion is simple and cost-effective method for the preparation of
Ce-based conversion coatings (CeCCs), a promising alternative to the toxic
chromate coatings, on the metal substrates. In this work CeCCs were prepared
on Al-alloy AA6060 from aqueous solution of cerium chloride at room
temperature. Effect of immersion time and post-treatment in phosphate
solution on the microstructure and corrosion properties of the coatings was
studied. The longer immersion time, the thicker but nonhomogeneous and
cracked CeCCs. The post-treatment contributed to the sealing of cracks, as
proven by an increase in corrosion resistance compared with as-deposited
coatings. CeCCs prepared at longer deposition time and post-treated showed
much better corrosion protection than those prepared at short deposition
time. A detailed EIS study was undertaken to follow the evolution of
corrosion behaviour of CeCCs with time of exposure to aggressive chloride
environment (3.5 % NaCl). For the sake of comparison, the EIS properties of
bare AA6060 were also investigated. A linear voltammetry was performed to
complete the study. Results confirmed a formation of protective CeCCs on
AA6060 surface. However, even CeCCs prepared at longer deposition time and
post-treated provided a short term protection in aggressive environment, due
to the small thickness.