bluuebunny/crossref_metadata_2025 huggingface dataset:
Trypanosoma brucei FKBP12 Differentially Controls Motility and Cytokinesis in Procyclic and Bloodstream Forms
Authors: Brasseur Anaïs , Rotureau Brice , Vermeersch Marjorie , Blisnick Thierry , Salmon Didier , Bastin Philippe , Pays Etienne , Vanhamme Luc , Pérez-Morga David
Published: October 2012

FKBP12 proteins are able to inhibit TOR kinases or calcineurin phosphatases upon binding of rapamycin or FK506 drugs, respectively. TheTrypanosoma bruceiFKBP12 homologue (TbFKBP12) was found to be a cytoskeleton-associated protein with specific localization in the flagellar pocket area of the bloodstream form. In the insect procyclic form, RNA interference-mediated knockdown ofTbFKBP12affected motility. In bloodstream cells, depletion of TbFKBP12 affected cytokinesis and cytoskeleton architecture. These last effects were associated with the presence of internal translucent cavities limited by an inside-out configuration of the normal cell surface, with a luminal variant surface glycoprotein coat lined up by microtubules. These cavities, which recreated the streamlined shape of the normal trypanosome cytoskeleton, might represent unsuccessful attempts for cell abscission. We propose that TbFKBP12 differentially affects stage-specific processes through association with the cytoskeleton.
Evidence that Two Pcl-Like Cyclins Control Cdk9 Activity during Cell Differentiation in Aspergillus nidulans Asexual Development
Authors: Kempf Claudia , Bathe Friederike , Fischer Reinhard
Published: October 2012

Cyclin-dependent protein kinases (CDKs) are usually involved in cell cycle regulation. However, Cdk9 is an exception and promotes RNA synthesis through phosphorylation of the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II (RNAPII). The CTD is comprised of repeating heptapeptides, in which serine residues at positions 2, 5, and 7 are of crucial importance. Ser5 phosphorylation causes transcription initiation and promoter escape. However, RNAPII pauses 20 to 50 bp downstream from the transcription start site, until Cdk9 phosphorylates Ser2. This event relieves the checkpoint and promotes the processivity of elongation. Here we present evidence that in the filamentous fungus
Aspergillus nidulans
, a Cdk9 homologue, PtkA, serves specific functions in conidiophore development. It was previously shown that PtkA interacts with two cyclins, PclA and the T cyclin PchA. Using yeast two-hybrid screens, we identified a third cyclin, PclB, and a kinase, PipA
Bud32
. Both proteins were expressed in hyphae and in conidiophores, but interaction between each protein and PtkA was restricted to the conidiophores. Deletion of
pchA
caused a severe growth defect, and deletion of
pipA
was lethal, suggesting basic functions in PtkA-dependent gene transcription. In contrast, deletion of
pclB
in combination with deletion of
pclA
essentially caused a block in spore formation. We present evidence that the phosphorylation status of the CTD of RNA polymerase II in the conidiophore changes upon deletion of
pclA
or
pclB
. Our results suggest that tissue-specific modulation of Cdk9 activity by PclA and PclB is required for proper differentiation.
Characterization of a Novel Class I Transcription Factor A (CITFA) Subunit That Is Indispensable for Transcription by the Multifunctional RNA Polymerase I of Trypanosoma brucei
Authors: Nguyen Tu N. , Nguyen Bao N. , Lee Ju Huck , Panigrahi Aswini K. , Günzl Arthur
Published: October 2012

Trypanosoma brucei
is the only organism known to have evolved a multifunctional RNA polymerase I (pol I) system that is used to express the parasite's ribosomal RNAs, as well as its major cell surface antigens, namely, the variant surface glycoprotein (VSG) and procyclin, which are vital for establishing successful infections in the mammalian host and the tsetse vector, respectively. Thus far, biochemical analyses of the
T. brucei
RNA pol I transcription machinery have elucidated the subunit structure of the enzyme and identified the class I transcription factor A (CITFA). CITFA binds to RNA pol I promoters, and its CITFA-2 subunit was shown to be absolutely essential for RNA pol I transcription in the parasite. Tandem affinity purification (TAP) of CITFA revealed the subunits CITFA-1 to -6, which are conserved only among kinetoplastid organisms, plus the dynein light chain DYNLL1. Here, by tagging CITFA-6 instead of CITFA-2, a complex was purified that contained all known CITFA subunits, as well as a novel proline-rich protein. Functional studies carried out
in vivo
and
in vitro
, as well as a colocalization study, unequivocally demonstrated that this protein is a bona fide CITFA subunit, essential for parasite viability and indispensable for RNA pol I transcription of ribosomal gene units and the active
VSG
expression site in the mammalian-infective life cycle stage of the parasite. Interestingly, CITFA-7 function appears to be species specific, because expression of an RNA interference (RNAi)-resistant
CITFA-7
transgene from
Trypanosoma cruzi
could not rescue the lethal phenotype of silencing endogenous
CITFA-7
.
Anaerobic Respiration Using a Complete Oxidative TCA Cycle Drives Multicellular Swarming in Proteus mirabilis
Authors: Alteri Christopher J. , Himpsl Stephanie D. , Engstrom Michael D. , Mobley Harry L. T.
Published: October 2012

Proteus mirabilis
rapidly migrates across surfaces using a periodic developmental process of differentiation alternating between short swimmer cells and elongated hyperflagellated swarmer cells. To undergo this vigorous flagellum-mediated motility, bacteria must generate a substantial proton gradient across their cytoplasmic membranes by using available energy pathways. We sought to identify the link between energy pathways and swarming differentiation by examining the behavior of defined central metabolism mutants. Mutations in the tricarboxylic acid (TCA) cycle (
fumC
and
sdhB
mutants) caused altered patterns of swarming periodicity, suggesting an aerobic pathway. Surprisingly, the wild-type strain swarmed on agar containing sodium azide, which poisons aerobic respiration; the
fumC
TCA cycle mutant, however, was unable to swarm on azide. To identify other contributing energy pathways, we screened transposon mutants for loss of swarming on sodium azide and found insertions in the following genes that involved fumarate metabolism or respiration:
hybB
, encoding hydrogenase;
fumC
, encoding fumarase;
argH
, encoding argininosuccinate lyase (generates fumarate); and a quinone hydroxylase gene. These findings validated the screen and suggested involvement of anaerobic electron transport chain components. Abnormal swarming periodicity of
fumC
and
sdhB
mutants was associated with the excretion of reduced acidic fermentation end products. Bacteria lacking SdhB were rescued to wild-type pH and periodicity by providing fumarate, independent of carbon source but dependent on oxygen, while
fumC
mutants were rescued by glycerol, independent of fumarate only under anaerobic conditions. These findings link multicellular swarming patterns with fumarate metabolism and membrane electron transport using a previously unappreciated configuration of both aerobic and anaerobic respiratory chain components.

IMPORTANCE
Bacterial locomotion and the existence of microbes were the first scientific observations that followed the invention of the microscope. A bacterium can swim through a fluid environment or coordinate motion with a group of bacteria and swarm across a surface. The flagellar motor, which propels the bacterium, is fueled by proton motive force. In contrast to the physiology that governs swimming motility, much less is known about the energy sources required for multicellular swarming on surfaces. In this study, we used
Proteus mirabilis
as a model organism to study vigorous swarming behavior and genetic and biochemical approaches to define energy pathways and central metabolism that contribute to multicellular motility. We found that swarming bacteria use a complete aerobic tricarboxylic acid (TCA) cycle but do not respire oxygen as the terminal electron acceptor, suggesting that multicellular cooperation during swarming reduces the amount of energy required by individual bacteria to achieve rapid motility.
Effects of Nitric Oxide Synthase Inhibition on Cutaneous Vasodilation in Response to Acupuncture Stimulation in Humans
Authors: Kimura Kenichi , Takeuchi Hayato , Yuri Kuniko , Wakayama Ikuro
Published: October 2012

Objectives

The aim of the present study was to elucidate the mechanism of cutaneous vasodilation following acupuncture stimulation by investigating the roles of nitric oxide (NO) and axon reflex vasodilation.

Methods

The subjects were 17 healthy male volunteers. The role of NO was investigated by administering NG-nitro-L-arginine methyl ester hydrochloride (L-NAME, 20 mM), an NO synthase inhibitor or Ringer's solution (control site), via intradermal microdialysis (protocol 1; n=7). The role of axon reflex vasodilation by local sensory neurones was investigated by comparing vasodilation at sites treated with ‘eutectic mixture of local anaesthetics’ (EMLA) cream (2.5% lidocaine and 2.5% prilocaine) with untreated sites (control site) (protocol 2; n=10). After 5 min of baseline recording, acupuncture was applied to PC4 and a control site in proximity to PC4 for 10 min and scanning was performed for 60 min after acupuncture stimulation. Skin blood flow (SkBF) was evaluated by laser Doppler perfusion imaging. Cutaneous vascular conductance (CVC) was calculated from the ratio of SkBF to mean arterial blood pressure.

Results

In the first protocol, sites administered L-NAME showed significant reductions in CVC responses following acupuncture stimulation compared to control sites (administered Ringer's solution) (p<0.05). In the second protocol, changes in CVC responses after acupuncture stimulation did not differ significantly between treated sites with EMLA cream and untreated sites (p>0.05).

Conclusions

These data suggest that cutaneous vasodilation in response to acupuncture stimulation may not occur through an axon reflex as previously reported. Rather, NO mechanisms appear to contribute to the vasodilator response.
Mapping and assessing clinical handover training interventions
Authors: Stoyanov Slavi , Boshuizen Henny , Groene Oliver , van der Klink Marcel , Kicken Wendy , Drachsler Hendrik , Barach Paul
Published: October 2012

Background

The literature reveals a patchwork of knowledge about the effectiveness of handover and transfer of care-training interventions, their influence on handover practices and on patient outcomes. We identified a range of training interventions, defined their content, and then proposed practical measures for improving the training effectiveness of handover practices.

Methods

We applied the Group Concept Mapping approach to identify objectively the shared understanding of a group of experts about patient handover training interventions. We collected 105 declarative statements about handover training interventions from an exhaustive literature review, and from structured expert interviews. The statements were then given to 21 healthcare and training design specialists to sort the statements on similarity in meaning, and rate them on their importance and feasibility.

Results

We used multidimensional scaling and hierarchical cluster analysis to depict the following seven clusters related to various handover training issues: standardisation, communication, coordination of activities, clinical microsystem care, transfer and impact, training methods and workplace learning.

Conclusions

Ideas on handover training interventions, grouped in thematic clusters, and prioritised on importance and feasibility creates a repository of approaches. This allows healthcare institutions to design and test concrete solutions for improving formal training and workplace learning related to handovers, and addressing informal social learning at the organisational level, with the aim of increasing impact on handover practice and patient outcomes. Measures need to be taken to assure a continuum of handover training interventions from formal training through workplace learning through less formal social learning, and to embed this training in the design of the clinical microsystem.
The key actor: a qualitative study of patient participation in the handover process in Europe
Authors: Flink Maria , Hesselink Gijs , Pijnenborg Loes , Wollersheim Hub , Vernooij-Dassen Myrra , Dudzik-Urbaniak Ewa , Orrego Carola , Toccafondi Giulio , Schoonhoven Lisette , Gademan Petra J , Johnson Julie K , Öhlén Gunnar , Hansagi Helen , Olsson Mariann , Barach Paul ,   on behalf of the HANDOVER Research Collaborative
Published: October 2012

Background

Patient safety experts have postulated that increasing patient participation in communications during patient handovers will improve the quality of patient transitions, and that this may reduce hospital readmissions. Choosing strategies that enhance patient safety through improved handovers requires better understanding of patient experiences and preferences for participation.

Objective

The aim of this paper is to explore the patients’ experiences and perspectives related to the handovers between their primary care providers and the inpatient hospital.

Methods

A qualitative secondary analysis was performed, based on individual and focus group patient interviews with 90 patients in five European countries.

Results

The analysis revealed three themes:patient positioning in the handover process;prerequisites for patient participationandpatient preferences for the handover process.Patients’ participation ranged from being the key actor, to sharing the responsibility with healthcare professional(s), to being passive participants. For active participation patients required both personal and social resources as well as prerequisites such as information and respect. Some patients preferred to be the key actor in charge; others preferred their healthcare professionals to be the key actors in the handover.

Conclusions

Patients’ participation is related to the healthcare system, the activity of healthcare professionals’ and patients’ capacity for participation. Patients prefer a handover process where the responsibility is clear and unambiguous. Healthcare organisations need a clear and well-considered system of responsibility for handover processes, that takes into account the individual patient's need of clarity, and support in relation to his/hers own recourses.
“It's like two worlds apart”: an analysis of vulnerable patient handover practices at discharge from hospital
Authors: Groene Raluca Oana , Orrego Carola , Suñol Rosa , Barach Paul , Groene Oliver
Published: October 2012

Background

Handover practices at hospital discharge are relatively under-researched, particularly as regards the specific risks and additional requirements for handovers involving vulnerable patients with limited language, cognitive and social resources.

Objective

To explore handover practices at discharge and to focus on the patients’ role in handovers and on the potential additional risks for vulnerable patients.

Methods

We conducted qualitative interviews with patients, hospital professionals and primary care professionals in two hospitals and their associated primary care centres in Catalonia, Spain.

Results

We identified handover practices at discharge that potentially put patients at risk. Patients did not feel empowered in the handover but were expected to transfer information between care providers. Professionals identified lack of medication reconciliation at discharge, loss of discharge information, and absence of plans for follow-up care in the community as quality and safety problems for discharge handovers. These occurred for all patients, but appeared to be more frequent and have a greater negative effect in patients with limited language comprehension and/or lack of family and social support systems.

Conclusions

Discharge handovers are often haphazard. Healthcare professionals do not consider current handover practices safe, with patients expected to transfer information without being empowered to understand and act on it. This can lead to misinformation, omission or duplication of tests or interventions and, potentially, patient harm. Vulnerable patients may be at greater risk given their limited language, cognitive and social resources. Patient safety at discharge could benefit from strategies to enhance patient education and promote empowerment.
Comparing the utility of a novel neonatal resuscitation cart with a generic code cart using simulation: a randomised, controlled, crossover trial
Authors: Chitkara Ritu , Rajani Anand K , Lee Henry C , Hansen Sara F Snyder , Halamek Louis P
Published: October 2012

Objective

To compare a novel neonatal resuscitation cart (NRC) to a generic code cart (GCC).

Study design

A prospective, randomised, controlled, crossover trial was performed to compare the utility of the NRC with the GCC during simulated deliveries of extremely low birthweight infants and infants with gastroschisis. Fifteen subjects participated. Mean times and accuracy of equipment and supply retrieval were compared for each scenario using the Wilcoxon test.

Results

Mean acquisition times for the NRC were always faster (by 58% to 74%) regardless of scenario (p<0.01). Accuracy of equipment selection did not differ. Ease of use was judged using a Likert scale (1=easiest to use; 5=most difficult), with mean score for NRC 1.1 and GCC 3.7 (p<0.0001). All subjects rated the NRC as easier to use.

Conclusions

The NRC was superior to the GCC in acquisition speed, supply selection and ease of use.
Capillary zone electrophoresis for haemoglobinopathy diagnosis
Authors: Borbely Nicole , Phelan Lorraine , Szydlo Richard , Bain Barbara
Published: October 2012

Aims

Capillary zone electrophoresis (CE) at alkaline pH is increasingly used in haemoglobinopathy diagnosis. We report our evaluation of automated CE, using the Capillarys 2 Flex Piercing instrument, as a routine diagnostic method for the detection of variant haemoglobins and the diagnosis of β thalassaemia.

Methods

A Capillarys 2 Flex Piercing instrument with Phoresis software was evaluated in our laboratory over a 6-week period, comparisons being made with high performance liquid chromatography (HPLC) and, for haemoglobin A2quantification, with microcolumn chromatography.

Results

The instrument was easy to use and was suitable for the quantification of haemoglobin A2. Quantification of A2was precise and the percentage was stable with ageing of the blood specimen. Results differ among HPLC, CE and microcolumn chromatography and use of an instrument-specific, method-specific reference range is therefore recommended until such time as there is standardisation between methods and manufacturers. Common variant haemoglobins were provisionally identified without difficulty. There are some uncommon variant haemoglobins that are detected by HPLC but not by capillary electrophoresis, but the reverse also occurs.

Conclusions

Capillary electrophoresis using a Capillarys 2 Flex Piercing instrument is suitable for haemoglobinopathy diagnosis.
The practicalities of using tissue slices as preclinical organotypic breast cancer models
Authors: Holliday Deborah L , Moss Marcus A , Pollock Steven , Lane Sally , Shaaban Abeer M , Millican-Slater Rebecca , Nash Claire , Hanby Andrew M , Speirs Valerie
Published: October 2012

Models considering breast cancer complexity cannot be easily or accurately replicated in routine cell line or animal models. We aimed to evaluate the practicality of organotypic tissue slice culture in breast cancer. Following ethical approval, 250 µm thick sections from surplus breast tumours (n=10) were prepared using a vibrating blade microtome. Triplicate tissue slices were placed in 6-well plates and cultured for up to 7 days±tamoxifen (1 nM) or doxorubicin (1 µM). Tissue slices were fixed and embedded before sectioning for morphological evaluation and immunohistochemistry. H&E showed good preservation of tissue morphology. Collagen production was evident. Biomarkers of proliferation and apoptosis could be evaluated using immunohistochemistry and used as surrogates to quantify drug effects. In summary, breast cancer tissue slices can be cultured in vitro as organotypic models. Nevertheless, although simple in concept, the delicacy of the model with regard to handling makes subsequent analytical processes challenging.
The financial costs to patients of diagnosing and excluding ectopic pregnancy
Authors: Unger Holger W , Starrs Lisa , Scott Linda , Critchley Hilary O D , Duncan W Colin , Horne Andrew W
Published: October 2012

Objectives

Health care costs are one of the greatest challenges in modern medicine. In gynaecology, diagnosing and excluding ectopic pregnancy (EP) has been shown to be a financial burden to health services because it commonly requires multiple investigations and hospital visits. However, the full economic costs are not captured by an analysis of health care costs alone. This study therefore aimed to assess the indirect costs to patients of diagnosing and excluding EP.

Methods

Patients presenting to a Pregnancy Support Centre in a large UK teaching hospital with abdominal pain and/or bleeding and a positive pregnancy test were recruited during the period June 2010–February 2011. Patients were provided with questionnaires to be completed at home and designed to record and quantify costs that they had incurred until a final diagnosis of their condition was made. A cost–description analysis was performed.

Results

52/203 (26%) recruited patients returned completed questionnaires. The mean cost to patients of diagnosing or excluding EP was £135.13±£51.60 (median £20.70). The main cost drivers identified were hospital visits, holiday cancellations, income loss and household help.

Conclusions

Quantification of the indirect costs of diagnosing and excluding EP is challenging because it relies on questionnaire feedback from patients at a time when they have suffered from the emotional impact of pregnancy loss. However, initial estimates suggest that such costs are significant due to diagnostic delays. This further highlights the importance of the development of potential biomarkers of EP to allow prompt diagnosis.
Advanced modality imaging evaluation in acute ischemic stroke may lead to delayed endovascular reperfusion therapy without improvement in clinical outcomes
Authors: Sheth Kevin N , Terry John B , Nogueira Raul G , Horev Anat , Nguyen Thanh N , Fong Albert K , Gandhi Dheeraj , Prabhakaran Shyam , Wisco Dolora , Glenn Brenda A , Tayal Ashis H , Ludwig Bryan , Hussain Muhammad Shazam , Jovin Tudor G , Clemmons Paul F , Cronin Carolyn , Liebeskind David S , Tian Melissa , Gupta Rishi
Published: October 2012

Purpose

Advanced neuroimaging techniques may improve patient selection for endovascular stroke treatment but may also delay time to reperfusion. We studied the effect of advanced modality imaging with CT perfusion (CTP) or MRI compared with non-contrast CT (NCT) in a multicenter cohort.

Materials and methods

This is a retrospective study of 10 stroke centers who select patients for endovascular treatment using institutional protocols. Approval was obtained from each institution's review board as only de-identified information was used. We collected demographic and radiographic data, selected time intervals, and outcome data. ANOVA was used to compare the groups (NCT vs CTP vs MRI). Binary logistic regression analysis was performed to determine factors associated with a good clinical outcome.

Results

556 patients were analyzed. Mean age was 66±15 years and median National Institutes of Health Stroke Scale score was 18 (IQR 14–22). NCT was used in 286 (51%) patients, CTP in 190 (34%) patients, and MRI in 80 (14%) patients. NCT patients had significantly lower median times to groin puncture (61 min, IQR (40–117)) compared with CTP (114 min, IQR (81–152)) or MRI (124 min, IQR (87–165)). There were no differences in clinical outcomes, hemorrhage rates, or final infarct volumes among the groups.

Conclusions

The current retrospective study shows that multimodal imaging may be associated with delays in treatment without reducing hemorrhage rates or improving clinical outcomes. This exploratory analysis suggests that prospective randomised studies are warranted to support the hypothesis that advanced modality imaging is superior to NCT in improving clinical outcomes.
Sensory neuromodulators in functional nausea and vomiting: predictors of response
Authors: Patel Amit , Sayuk Gregory S , Kushnir Vladimir M , Gyawali C Prakash
Published: October 2012

Background

Tricyclic antidepressants (TCAs) are known to benefit subjects with functional nausea and vomiting (FNV), but it is not known if alternate neuromodulators are also beneficial. We retrospectively evaluated outcomes and clinical predictors of response in FNV subjects treated with any neuromodulator, including TCAs.

Methods

We identified 94 subjects (43.8±1.4 year, 79 F) with FNV (Rome III criteria) over a 12 year period, treated with neuromodulators and followed up for 8.5±1.1 months. Clinical presentation, demographics and gastric emptying study (GES) findings (when available) were extracted. Likert scales determined symptom severity at baseline and symptom response or remission at follow-up. Outcomes and predictors of response were evaluated using univariate and multivariate analyses.

Results

At least moderate symptom improvement was reported by 72.3%, and 22.3% had symptom remission. Proportions achieving moderate improvement and remission, and mean outcome Likert scores were similar regardless of neuromodulator agent used or GES status. On univariate and multivariate logistic regression analysis, baseline symptom severity affected symptom response, and pain negatively impacted symptom remission to treatment (p≤0.04 for each); GES status failed to predict treatment response or remission.

Conclusions

Symptom improvement with neuromodulators may be seen in over two-thirds of subjects with FNV regardless of the specific agent administered. Response may be suboptimal in pain predominant presentations.
A new infectious disease model for estimating and projecting HIV/AIDS epidemics
Authors: Bao Le
Published: October 2012

Objectives

As the global HIV pandemic enters its fourth decade, countries have collected longer time series of surveillance data, and the AIDS-specific mortality has been substantially reduced by the increasing availability of antiretroviral treatment. A refined model with a greater flexibility to fit longer time series of surveillance data is desired.

Methods

In this article, we present a new epidemiological model that allows the HIV infection rate, r(t), to change over years. The annual change of infection rate is modelled by a linear combination of three key factors: the past prevalence, the past infection rate and a stabilisation condition. We focus on fitting the antenatal clinic (ANC) data and household surveys which are the most commonly available data source for generalised epidemics defined by the overall prevalence being above 1%. A hierarchical model is used to account for the repeated measurement within a clinic. A Bayesian approach is used for the parameter estimation.

Results

We evaluate the performance of the newly proposed model on the ANC data collected from urban and rural areas of 31 countries with generalised epidemics in sub-Sahara Africa. The three factors in the proposed model all have significant contributions to the reconstruction of r(t) trends. It improves the prevalence fit over the classic Estimation and Projection Package model and provides more realistic projections when the classic model encounters problems.

Conclusions

The proposed model better captures the main pattern of the HIV/AIDS dynamic. It also retains the simplicity of the classic model with a few interpretable parameters that are easy to interpret and estimate.
Rumen–reticulum characteristics, scaling relationships, and ontogeny in white-tailed deer (Odocoileus virginianus)
Authors: Luna R.S. , Duarte A. , Weckerly F.W.
Published: October 2012

Scaling relationships between body mass and gut capacity are valuable to predicting digestive efficiency. Interspecific scaling relationships between body mass and gut capacity have consistently estimated a slope of 1.0; however, intraspecific scaling relationships between body mass and gut capacity have been highly variable. We examined the influence of demands of growth and production on scaling relationships of body mass and rumen–reticulum characteristics in white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)) because little is known about how juvenile and subadult ruminants accommodate increased digesta masses. We sampled 108 animals over a 2-year period and assessed the influence of body mass, time of kill, crude protein (%), and acid detergent fiber (%) in the rumen, lactation, sex, and back fat on rumen–reticulum organ mass, rumen–reticulum capacity, wet mass of the digesta, and the dry mass of the digesta. Juvenile and subadult white-tailed deer had rumen–reticulum organ masses, capacity, and digesta masses that were similar to adults because body mass and rumen–reticulum scaling relationships all had scalars similar to 1.0. Thus, under the confines of our study, ontogeny plays only a minor role in the physiological characteristics of the rumen–reticulum and the scaling relationships of body mass and rumen–reticulum capacity.
Maternal age, fecundity, egg quality, and recruitment: linking stock structure to recruitment using an age-structured Ricker model
Authors: Shelton Andrew O. , Munch Stephan B. , Keith David , Mangel Marc
Published: October 2012

Understanding the process of recruitment is fundamental to fisheries biology and management. However, recruitment in natural populations is highly variable and rarely well described by classical stock–recruitment relationships (SRRs). Recent analyses suggest that the age composition of the spawning biomass may play an important role in the mismatch between SRRs and data. Here we develop a generalization of the Ricker SRR that incorporates age structure by allowing mortality and fecundity rates to depend on maternal age. We provide a flexible SRR with biologically interpretable parameters that can be estimated from existing fisheries time series and use a Bayesian framework that enables parameters to be informed by experimental data. We apply our method to the Icelandic population of Atlantic cod ( Gadus morhua ) and show models that include age structure effects outperform the classical Ricker SRR that ignores age structure. Our results indicate a strong effect of spawning stock age structure on recruitment dynamics in this population. Our approach provides a biologically interpretable and immediately applicable method for investigating the consequences for spawning stock age structure on recruitment.
Sexual conflict inGerris gillettei(Insecta: Hemiptera): influence of effective mating rate and morphology on reproductive success
Authors: Gagnon Marie-Claude , Duchesne Pierre , Turgeon Julie
Published: October 2012

In water striders, the interests of both sexes diverge over the decision to mate, leading to precopulatory sexual conflict. The influence of mating rate and key persistence and resistance traits on reproductive success has seldom been investigated in the context of multiple matings. We used amplified fragment length polymorphism (AFLP) based genetic parentage analyses to estimate mating and reproductive success in Gerris gillettei Lethierry and Severin, 1896, while allowing for free multiple matings. We tested the hypotheses that males should display stronger opportunity for sexual selection and steeper Bateman gradients. In each sex, persistence and resistance traits should also impact mating and reproductive success. Surprisingly, males and females had similarly high and variable effective mating rates (i.e., number of genetic partners), and both sexes produce more offspring when mating with more partners. As predicted, exaggerated persistence traits allowed males to mate with more partners and sire more offspring. However, we found no evidence for an impact of resistance traits for females. The mating environment may have favoured low resistance in females, but high promiscuity can be beneficial for females. This first description of the genetic mating system for a water strider species suggests that the determinants of fitness can be further deciphered using the sexual selection framework.
ANGULAR MOMENTUM DECOMPOSITION OF CHIRAL MULTIPLETS IN FRONT FORM
Authors: GÓMEZ-ROCHA MARÍA
Published: October 2012

In this paper, we derive the unitary transformation that relates the [Formula: see text] chiral basis {R;IJPC} to the {I;2S+1LJ}-basis in a front-form framework. From the most general expression for the Clebsch–Gordan coefficients of the Poincaré group one can see that the chiral limit brings the angular momentum coupling into a simple form that permits the relation in terms of SU(2) Clebsch–Gordan coefficients. We demonstrate that such a transformation is identical to the one obtained for canonical spin in the instant form.
HALF-LIVES WITH YUKAWA PROXIMITY POTENTIAL FOR ALPHA-DECAY PROCESS
Authors: JAVADIMANESH E. , HASSANABADI H. , RAJABI A. A. , RAHIMOV H. , ZARRINKAMAR S.
Published: October 2012

We intend to study the alpha-decay half-lives of some nuclei from ground state to ground state. We consider a potential model with Yukawa proximity potential. We see that the results are in good agreement with the experimental data.
COUNTING UNFOLDING EVENTS IN STRETCHED HELICES WITH INDUCED OSCILLATION BY OPTICAL TWEEZERS
Authors: BACABAC ROMMEL GAUD , OTADOY ROLAND
Published: October 2012

Correlation measures based on embedded probe fluctuations, single or paired, are now widely used for characterizing the viscoelastic properties of biological samples. However, more robust applications using this technique are still lacking. Considering that the study of living matter routinely demonstrates new and complex phenomena, mathematical and experimental tools for analysis have to catch up in order to arrive at newer insights. Therefore, we derive ways of probing non-equilibrium events in helical biopolymers provided by stretching beyond thermal forces. We generalize, for the first time, calculations for winding turn probabilities to account for unfolding events in single fibrous biopolymers and globular proteins under tensile stretching using twin optical traps. The approach is based on approximating the ensuing probe fluctuations as originating from a damped harmonic oscillator under oscillatory forcing.
FRACTIONAL BROWNIAN POLYMERS - SOME FIRST RESULTS
Authors: BORNALES JINKY , ELEUTÉRIO SAMUEL , OLIVEIRA MARIA JOÃO , STREIT LUDWIG
Published: October 2012

Recently the Edwards model for chain polymers in good solvents has been extended to include fractional Brownian motion trajectories as a description of polymer conformations. This raises in particular the question of the corresponding Flory formula for the end-to-end length of those molecules. A generalized Flory formula has been proposed, and there are some first results of numerical validations.
FIELD THEORY APPROACH IN THE DYNAMICS OF BIOMATTER
Authors: HANDOKO L. T.
Published: October 2012

A new approach to model the biomatter dynamics based on the field theory is presented. It is shown that some well known tools in field theory can be utilized to describe the physical phenomena in life matters, in particular at elementary biomatters like DNA and proteins. In this approach, the biomatter dynamics are represented as results of interactions among its elementary matters in the form of lagrangian. Starting from the lagrangian would provide stronger underlying theoretical consideration for further extension. Moreover, it also enables us to acquire rich physical observables using statistical mechanics instead of relying on the space-time dynamics from certain equation of motions which is not solvable due to its nonlinearities. Few examples from previous results are given and explained briefly.
STOCHASTIC MODELLING OF HELICAL BIOPOLYMERS
Authors: ARINGA HENRY P. , BERNIDO CHRISTOPHER C. , CARPIO-BERNIDO M. VICTORIA , BORNALES JINKY B.
Published: October 2012

We model helical polypeptides in an aqueous environment by explicitly evaluating winding probabilities of biopolymers. To account for differences in reaction to the solvent of the various types of amino acids forming the chainlike biopolymer, a length-dependent drift coefficient A(s) is used. As an application, we express A(s) in terms of a Bessel function to generate a sequence of winding and non-winding segments and compare this with the α-helical segments of myoglobin.
A STOCHASTIC MODEL FOR THE SPREADING OF AN IDEA IN A HUMAN COMMUNITY
Authors: WIEGEL FREDERIK W.
Published: October 2012

We call an idea "alive" in a human community of N individuals, if at least one of them accepts it. Such an individual will create "copies" of this idea; any such free-floating copy has a probability to be accepted by any other individual. In this way the idea can spread through the community. The opposite processes can also occur: somebody can drop a previously held notion; any free-floating copy of an idea can be annihilated (newspapers get thrown away, for example). We present a simplified stochastic model for these processes. The various transition probabilities combine into a single, dimensionless constant. A generating function technique is used to formulate the dynamics of the model in terms of a partial differential equation, which is first order in the time variable and second order in the auxiliary variable. Using this equation we calculate exactly the average life-time of an idea (the time between the moment the idea is "born" in a single individual, and the moment the idea goes extinct because it is dropped by the last person who still accepted it). This average life-time is a function of the dimensionless constant and N. It has a quite different form for the three basic cases in which the product of the dimensionless constant and N-1 is larger than, equal to, or smaller than unity. In the last section various extensions and relevant questions are discussed in a qualitative way.
FRACTIONAL PATH INTEGRATION FOR GROWTH DYNAMICS AND SCALING BEHAVIOR IN COMPLEX SYSTEMS
Authors: BERNIDO CHRISTOPER C. , ESCOBIDO MATTHEW G. O. , CARPIO-BERNIDO M. VICTORIA
Published: October 2012

An analytical model for growth rates in complex systems based on the sum-over-all-histories approach is presented. To endow the rate of growth with memory of the past, fractional Brownian paths are used. A probability distribution function and its Laplace transform are evaluated and compared with an empirical formula derived from data of selected complex systems. Scaling behavior of these systems is also discussed.
PRODUCT INTERACTIONS AND INDUSTRY SHAKEOUT
Authors: ESCOBIDO M. G. O.
Published: October 2012

We construct an industry shakeout model based on the Cournot competition of firms each producing a differentiated product and adjusting their output according to the diffusion of their respective product. We investigate the resulting Lotka-Volterra dynamics and present a coexistence region that is a function of the interaction among the products. We show that as the products become less differentiated, the competition intensifies and the coexistence region contracts. The extent of the shakeout depends on the distribution of the competitive interactions among firms in the industry.
NEW METHOD FOR SCHRÖDINGER EIGENVALUE PROBLEM — The Case of the Potential V(x) = 2μx2 + λx4
Authors: NAKAMURA TORU , EZAWA HIROSHI , WATANABE KEIJI , IRISAWA TOSHIHARU
Published: October 2012

A new method is proposed to solve the Schrödinger eigenvalue problem. Remarkably the iteration procedure is found to be convergent in the case of the quartic potential for which the perturbation and the WKB method are known to give divergent series.
Nordihydroguaiaretic acid improves metabolic dysregulation and aberrant hepatic lipid metabolism in mice by both PPARα-dependent and -independent pathways
Authors: Zhang Haiyan , Shen Wen-Jun , Cortez Yuan , Kraemer Fredric B. , Azhar Salman
Published: October 2012

Creosote bush-derived nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, possesses antioxidant properties and functions as a potent antihyperlipidemic agent in rodent models. Here, we examined the effect of chronic NDGA treatment of ob/ob mice on plasma dyslipidemia, hepatic steatosis, and changes in hepatic gene expression. Feeding ob/ ob mice a chow diet supplemented with either low (0.83 g/kg diet) or high-dose (2.5 g/kg diet) NDGA for 16 wk significantly improved plasma triglyceride (TG), inflammatory chemokine levels, hyperinsulinemia, insulin sensitivity, and glucose intolerance. NDGA treatment caused a marked reduction in liver weight and TG content, while enhancing rates of fatty acid oxidation. Microarray analysis of hepatic gene expression demonstrated that NDGA treatment altered genes for lipid metabolism, with genes involved in fatty acid catabolism most significantly increased. NDGA upregulated the mRNA and nuclear protein levels of peroxisome proliferator-activated receptor α (PPARα), and the activated (phosphorylated) form of AMP-activated kinase. NDGA increased PPARα promoter activity in AML12 hepatocytes and also prevented the fatty acid suppression of PPARα expression. In contrast, PPARα siRNA abrogated the stimulatory effect of NDGA on fatty acid catabolism. Likewise, no stimulatory effect of NDGA on hepatic fatty acid oxidation was observed in the livers of PPARα-deficient mice, but the ability of NDGA to reverse fatty liver conditions was unaffected. In conclusion, the beneficial actions of NDGA on dyslipidemia and hepatic steatosis in ob/ob mice are exerted primarily through enhanced fatty acid oxidation via PPARα-dependent pathways. However, PPARα-independent pathways also contribute to NDGA's action to ameliorate hepatic steatosis.
Complement depletion protects lupus-prone mice from ischemia-reperfusion-initiated organ injury
Authors: Ioannou Antonis , Lieberman Linda A. , Lucca Jurandir J. Dalle , Tsokos George C.
Published: October 2012

Ischemia-reperfusion (IR) injury causes a vigorous immune response that is amplified by complement activation, leading to local and remote tissue damage. Using MRL /lpr mice, which are known to experience accelerated tissue damage after mesenteric IR injury, we sought to evaluate whether complement inhibition mitigates organ damage. We found that complement depletion with cobra venom factor protected mice from local and remote lung tissue damage. Protection from injury was associated with less complement (C3) and membrane attack complex deposition, less neutrophil infiltration, and lower levels of local proinflammatory cytokine production. In addition, complement depletion was able to decrease the level of oxidative stress as measured by glutathione peroxidase 1 mRNA levels and superoxide dismutase activity. Furthermore, blockage of C5a receptor protected MRL/ lpr mice from local tissue damage, but not from remote lung tissue damage. In conclusion, although treatments with cobra venom factor and C5a receptor antagonist were able to protect mice from local tissue damage, treatment with C5a receptor antagonist was not able to protect mice from remote lung tissue damage, implying that more factors contribute to the development of remote tissue damage after IR injury. These data also suggest that complement inhibition at earlier, rather than late, stages can have clinical benefit in conditions that are complicated with IR injury.
Chronic hypoxia decreases arterial and venous compliance in isolated perfused rat lungs: an effect that is reversed by exogenous l-arginine
Authors: Jin Yi , Chen Bernadette , Calvert Thomas J. , Chicoine Louis G. , Liu Yusen , Nelin Leif D.
Published: October 2012

Chronic hypoxia (CH)-induced pulmonary hypertension is characterized by vasoconstriction and vascular remodeling, leading to right ventricular dysfunction. Given the role of arterial compliance ( Ca) in right ventricular work, a decrease in Ca would add to right ventricular work. Nitric oxide (NO) is a potent vasodilator made by NO synthases from l-arginine (l-Arg). However, little is known of the effect of l-Arg on vascular compliance ( Cv) in the lung. We hypothesized that exposure to CH would decrease Ca and that this effect would be reversed by exogenous l-Arg. Sprague-Dawley rats were exposed to either normoxia or CH for 14 days; the lungs were then isolated and perfused. Vascular occlusions were performed and modeled using a three-compliance, two-resistor model. Pressure-flow curves were generated, and a distensible vessel model was used to estimate distensibility and a vascular resistance parameter ( R0). Hypoxia resulted in the expected increase in arterial resistance ( Ra) as well as a decrease in both Ca and Cv. l-Arg had little effect on Ra, Ca, or Cv in isolated lungs from normoxic animals. l-Arg decreased Ra in lungs from CH rats and redistributed compliance to approximately that found in normoxic lungs. CH increased R0, and l-Arg reversed this increase in R0. l-Arg increased exhaled NO, and inhibition of l-Arg uptake attenuated the l-Arg-induced increase in exhaled NO. These data demonstrate that the CH-induced decrease in Ca was reversed by l-Arg, suggesting that l-Arg may improve CH-induced right ventricular dysfunction.
Role of endothelin-A receptors in optic nerve head red cell flux regulation during isometric exercise in healthy humans
Authors: Boltz Agnes , Schmidl Doreen , Werkmeister René M. , Lasta Michael , Kaya Semira , Palkovits Stefan , Told Reinhard , Frantal Sophie , Garhöfer Gerhard , Schmetterer Leopold
Published: October 2012

Endothelin-1 (ET-1) is an important regulator of vascular tone in the eye. It appears to play a role in ocular disease because of its strong vasoconstrictor action, its role in intraocular pressure homeostasis, and its neurotoxic potential. We have previously shown that ET-1 is involved in choroidal red cell flux (RCF) regulation during isometric exercise in healthy humans. In the present study we hypothesized that ET-1 also plays a role in optic nerve head (ONH) RCF regulation during isometric exercise. To test this hypothesis, we performed a randomized, double-masked, placebo-controlled, two-way crossover study in 15 healthy volunteers. Subjects were randomized to receive intravenous infusions of the specific endothelin type A receptor antagonist BQ-123 and placebo on two different study days. During these infusion periods, subjects performed squatting for 6 min to increase ocular perfusion pressure (OPP). ONH RCF was assessed with laser-Doppler flowmetry, and OPP was calculated from mean arterial pressure and intraocular pressure. BQ-123 did not change OPP or ONH RCF at baseline. The relative increase in OPP during isometric exercise was comparable between both groups (between 84 and 88%, P = 0.76 between groups; P < 0.001 vs. baseline). Isometric exercise increased ONH RCF during placebo and BQ-123, but the increase was more pronounced when the endothelin type-A receptor antagonist was administered (placebo, 27.3 ± 5.4%; and BQ-123, 39.2 ± 4.4%; P = 0.007 between groups). The present data indicate that ET-1 regulates red cell flux in the ONH beyond the autoregulatory range.