bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk of venous thromboembolism and benefits of prophylaxis use in hospitalized medically ill US patients up to 180 days post-hospital discharge
Authors: Wang Li , Sengupta Nishan , Baser Onur
Published: November 2011

Background

To assess the incidence of venous thromboembolism (VTE) and bleeding events with or without thromboprophylaxis and the associated costs in a cohort of medically ill patients in both in-hospital and outpatient settings.

Methods

A large hospital drug database and linked outpatient files were used to identify patients eligible for this analysis, based on demographic and clinical characteristics.

Results

Among 11,135 patients identified, 1592 (14.30%) were admitted with chronic heart failure, 1684 (15.12%) with thromboembolic stroke, 3834 (34.43%) with severe lung disease, 1658 (14.89%) with acute infection, and 2367 (21.26%) with cancer. Of the 11,135 patients, 5932 received anticoagulant therapy at some point during their hospitalization and until 30 days after discharge. VTE events occurred in 1.30% of patients who received anticoagulant prophylaxis versus 2.99% of patients who did not. Risk-adjusted total healthcare costs for patients with a VTE or major or minor bleeding event were significantly higher than for those without events (VTE: $52,157 ± 24,389 vs $24,164 ± 11,418; major bleeding: $33,656 ± 18,196 vs $24,765 ± 11,974; minor bleeding: $33,690 ± 14,398 vs $23,610 ± 11,873). In a multivariate analysis, appropriate anticoagulant prophylaxis use was significantly associated with a reduced risk of clinical VTE, compared with no anticoagulant use (hazard ratio: 0.37). Patients admitted with thromboembolic stroke were less likely to have a VTE than patients admitted with cancer (hazard ratio: 0.42).

Conclusions

In this analysis, VTE and major bleeding event rates were lower for patients who received prophylaxis compared with those who did not. Prophylaxis use was associated with lower healthcare costs.
Mapping codon usage of the translation initiation region in porcine reproductive and respiratory syndrome virus genome
Authors: Su Jun-hong , Ma Xiao-xia , He Ya-li , Li Ji-dong , Ma Xu-sheng , Dou Yong-xi , Luo Xue-nong , Cai Xue-peng
Published: November 2011

Background

Porcine reproductive and respitatory syndrome virus (PRRSV) is a recently emerged pathogen and severely affects swine populations worldwide. The replication of PRRSV is tightly controlled by viral gene expression and the codon usage of translation initiation region within each gene could potentially regulate the translation rate. Therefore, a better understanding of the codon usage pattern of the initiation translation region would shed light on the regulation of PRRSV gene expression.

Results

In this study, the codon usage in the translation initiation region and in the whole coding sequence was compared in PRRSV ORF1a and ORFs2-7. To investigate the potential role of codon usage in affecting the translation initiation rate, we established a codon usage model for PRRSV translation initiation region. We observed that some non-preferential codons are preferentially used in the translation initiation region in particular ORFs. Although some positions vary with codons, they intend to use codons with negative CUB. Furthermore, our model of codon usage showed that the conserved pattern of CUB is not directly consensus with the conserved sequence, but shaped under the translation selection.

Conclusions

The non-variation pattern with negative CUB in the PRRSV translation initiation region scanned by ribosomes is considered the rate-limiting step in the translation process.
Metaphor, Narrative, and the Promotion of Public Health
Authors: Talley Janine
Published: November 2011

Public health promotion in the United Kingdom is pervaded by metaphor and narrative. This is largely unacknowledged and unexamined. Metaphor and narrative are important in shaping discourse and practice. Examples of their use are examined in a range of areas from health education to policy. Metaphor is shown to reflect and generate narratives related to what health is, what affects health, and what can be done to improve health. Mechanical, ecological, and other metaphors are described. The valuable metaphor of journey is highlighted. Metaphor and narrative are powerful constructs with positive and negative actual and potential outcomes. Their application to enhancing health and well-being is emphasized.
A Short Long Story: Mapping the Course of Pain
Authors: McEntyre Marilyn
Published: November 2011

This article considers the value of narrative poetry for stories of illness, a form that holds the facts of those stories in creative tension between extension and compression, elaboration and implication, chronological time and the timeless moment. Narrative and metaphor converge there as complementary epistemic devices and empower poets by differently accommodating the complexities of pain. Metaphors become important when they offer patients a way to understand their conditions and when they enable doctors or caregivers to reimagine the patient's experience. One example of a narrative poem that gives shape to illness and loss is Alan Chong Lau's “my ship does not need a helmsman.” It adopts the metaphor of journey to speak about the course of an illness and the prospect of death. The speaker is dying far from home. In short lines the poem creates discontinuities even as it opens long vistas of memory. It enumerates sounds, smells, and objects that give a thick sense of the patient's point of view. A close reading reveals how the poem articulates the emotional complexity of the speaker's sense of impending death—from disgust and loneliness, to homesickness and political apathy, to longing for a woman.
Genes, Eyeglasses, and Social Policy
Authors: Manski Charles F
Published: November 2011

Someone reading empirical research relating human genetics to personal outcomes must be careful to distinguish two types of work: An old literature on heritability attempts to decompose cross-sectional variation in observed outcomes into unobservable genetic and environmental components. A new literature measures specific genes and uses them as observed covariates when predicting outcomes. I will discuss these two types of work in terms of how they may inform social policy. I will argue that research on heritability is fundamentally uninformative for policy analysis, but make a cautious argument that research using genes as covariates is potentially informative.
The Composition and Drawdown of Wealth in Retirement
Authors: Poterba James , Venti Steven , Wise David
Published: November 2011

This paper presents evidence on the resources available to households as they enter retirement. It draws heavily on data collected by the Health and Retirement Study. We calculate the “potential additional annuity income” that households could purchase, given their holdings of non-annuitized financial assets at the start of retirement. We also consider the role of housing equity in the portfolios of retirement-age households and explore the extent to which households draw down housing equity and financial assets as they age. Because home equity is often conserved until very late in life, for many households it may provide some insurance against the risk of living longer than expected. Finally, we consider how our findings bear on a number of policy issues, such as the role for annuity defaults in retirement saving plans.
Effect of Telavancin (Vibativ) on Routine Coagulation Test Results
Authors: Gosselin Robert , Dager William , Roberts Aaron , Freeman Leslie , Gandy Lisa , Gregg Jeffrey , Dwyre Denis
Published: November 2011

Telavancin (Vibativ, Astellas Pharma US, Deerfield, IL) is a lipoglycopeptide antibiotic that has activity against gram-positive microorganisms, but also has the ability to bind to artificial phospholipids found in coagulation reagents. Normal pooled plasma was spiked with telavancin to obtain concentrations of 0, 12.5, 25, 50, 75, 100, 125, and 150 μg/mL of drug. Samples were tested using 3 different prothrombin time/international normalized ratio (INR) and activated partial thromboplastin time (aPTT) reagent systems, as well as for fibrinogen level, thrombin time, D-dimer level, dilute Russell viper venom time (DRVVT), protein C activity, and protein S activity. There was no effect of telavancin seen with non–phospholipid-dependent assays: fibrinogen level, thrombin time, and D-dimer testing. All INR and aPTT systems demonstrated concentration-dependent increases in clotting times, with Innovin (Siemens Healthcare Diagnostics, Deerfield, IL) INRs the most dramatic. False-positive DRVVT ratios started at 12.5 μg/mL of telavancin, with no effect on protein C or protein S levels until the telavancin level reached more than 100 μg/mL.
Different HER2 Protein Expression Profiles Aid in the Histologic Differential Diagnosis Between Urothelial Carcinoma In Situ (CIS) and Non-CIS Conditions (Dysplasia and Reactive Atypia) of the Urinary Bladder Mucosa
Authors: Gunia Sven , Koch Stefan , Hakenberg Oliver W. , May Matthias , Kakies Christoph , Erbersdobler Andreas
Published: November 2011

We evaluated HER2 expression profiles in 32 carcinoma in situ (CIS) and 31 non-CIS conditions (5 dysplasia and 26 reactive atypia) of the urinary bladder mucosa by applying breast cancer scoring rules. In situ hybridization was performed on tissue microarrays to assess HER2 gene amplification status. Our immunoprofiling data disclosed moderate to strong HER2 expression in CIS, including the basal layer of the urothelium, and absent to weak HER2 expression in non-CIS conditions. From the histologic differential diagnostic standpoint, immunostaining for HER2 protein represents a useful adjunct to aid in the delineation between CIS and non-CIS conditions of the bladder mucosa. Pathogenically, aberrant HER2 protein expression in CIS seems to be more commonly associated with polysomy than with gene amplification. From a therapeutic viewpoint, prospective clinical studies should investigate the potential benefit of HER2-targeted therapies in CIS, particularly in cases unresponsive to conventional therapeutic regimens.
Morphological variation in a small Thalassiosira species (Bacillariophyta) under different culture regimes
Authors: Martín-Cereceda Mercedes , Cox Eileen J.
Published: November 2011

The structure of a small marine planktonic centric diatom belonging to the genus Thalassiosira was characterised using electron microscopy; and data on its ultrastructure, autecology and initial valve formation are provided here. Although our specimens shared some characteristics with Thalassiosira proschkinae sensu lato, they differed from the type in their permanent lack of areolae and in being constitutively weakly silicified, regardless of the silicate concentration in the medium. Valve areolation in our Thalassiosira isolate was less pronounced than in many other members of the genus and varied with salinity. The most significant effect of changing salinity was that the areola pattern becomes more diffuse, so that it was more difficult to observe areolae even at the margin of the valve. A decrease in salinity also induced changes in cell size, number of marginal fultoportulae and surface architecture. Cells in very low salinity (2) died after 24–48 h. Low silicate in the culture medium affected cell diameter (10% increase in the presence of added silicate). Putative auxospores and initial cells were found in some of the cultures, and some interesting variations in the valve morphology of initial cells were observed.
Identification of hypo-osmotically induced genes in Kappaphycus alvarezii (Solieriaceae, Rhodophyta) through expressed sequence tag analysis
Authors: Liu Chenlin , Wang Xiuliang , Huang Xiaohang , Liu Jianguo
Published: November 2011

Hypo-osmotic conditions are among the most stressful environmental factors that affect seaweed physiology and productivity. To improve understanding of hypo-osmotic adaptation and to find genes involved in low salinity stress, we conducted an analysis of expressed sequence tags (ESTs) on the κ-carrageenan-producing red algae, Kappaphycus alvarezii. Of 454 tentatively unique genes (TUGs), 281 matched protein sequences by BlastX analysis (e value≤10-3), 112 TUGs matched ESTs from other agar- or carrageenan-producing red algae, and 98 TUGs were annotated. The transcriptional profiles of six functional genes from K. alvarezii ESTs were examined. An ATP-binding cassette transporter gene and a sodium phosphate symporter gene were significantly up-regulated, indicating the importance of membrane transport proteins in coping with hypo-osmotic stress conditions.
Photovoltaics: Status and Perspectives until 2020
Authors: Jäger-Waldau Arnulf
Published: November 2011

Since 2000, total PV production increased almost by two orders of magnitude, with a compound annual growth rate of over 55%. The most rapid growth in annual cell and module production over the last five years could be observed in Asia, where China and Taiwan together now account for more than 60% of world-wide production. Prices for photovoltaic electricity generation systems have more than halved over the last five years making the technology affordable to an ever increasing number of customers worldwide. The photovoltaic industry is in a process to mature and in this course increasing industry consolidation takes place. This process presents a risk as well as an opportunity at the same time, opening more and more markets. Various installation scenarios published during the last three years vary significantly depicting photovoltaic electricity generation from insignificant to a major energy source. With worldwide 50 GW cumulative installed photovoltaic electricity generation capacity installed in September 2011, photovoltaics still is a small contributor to the electricity supply, but its importance for our future energy mix is finally acknowledged.
Epigenetic Regulation of Motor Neuron Cell Death through DNA Methylation
Authors: Chestnut Barry A. , Chang Qing , Price Ann , Lesuisse Catherine , Wong Margaret , Martin Lee J.
Published: November 2011

DNA methylation is an epigenetic mechanism for gene silencing engaged by DNA methyltransferase (Dnmt)-catalyzed methyl group transfer to cytosine residues in gene-regulatory regions. It is unknown whether aberrant DNA methylation can cause neurodegeneration. We tested the hypothesis that Dnmts can mediate neuronal cell death. Enforced expression of Dnmt3a induced degeneration of cultured NSC34 cells. During apoptosis of NSC34 cells induced by camptothecin, levels of Dnmt1 and Dnmt3a increased fivefold and twofold, respectively, and 5-methylcytosine accumulated in nuclei. Truncation mutation of the Dnmt3a catalytic domain and Dnmt3a RNAi blocked apoptosis of cultured neurons. Inhibition of Dnmt catalytic activity with RG108 and procainamide protected cultured neurons from excessive DNA methylation and apoptosis.In vivo, Dnmt1 and Dnmt3a are expressed differentially during mouse brain and spinal cord maturation and in adulthood when Dnmt3a is abundant in synapses and mitochondria. Dnmt1 and Dnmt3a are expressed in motor neurons of adult mouse spinal cord, and, during their apoptosis induced by sciatic nerve avulsion, nuclear and cytoplasmic 5-methylcytosine immunoreactivity, Dnmt3a protein levels and Dnmt enzyme activity increased preapoptotically. Inhibition of Dnmts with RG108 blocked completely the increase in 5-methycytosine and the apoptosis of motor neurons in mice. In human amyotrophic lateral sclerosis (ALS), motor neurons showed changes in Dnmt1, Dnmt3a, and 5-methylcytosine similar to experimental models. Thus, motor neurons can engage epigenetic mechanisms to drive apoptosis, involving Dnmt upregulation and increased DNA methylation. These cellular mechanisms could be relevant to human ALS pathobiology and disease treatment.
Critical Roles of Transitional Cells and Na/K-ATPase in the Formation of Vestibular Endolymph
Authors: Bartolami Sylvain , Gaboyard Sophie , Quentin Julie , Travo Cécile , Cavalier Mélanie , Barhanin Jacques , Chabbert Christian
Published: November 2011

The mechanotransduction of vestibular sensory cells depends on the high endolymphatic potassium concentration ([K+]) maintained by a fine balance between K+secretion and absorption by epithelial cells. Despite the crucial role of endolymph as an electrochemical motor for mechanotransduction, little is known about the processes that govern endolymph formation. To address these, we took advantage of an organotypic rodent model, which regenerates a genuine neonatal vestibular endolymphatic compartment, facilitating the determination of endolymphatic [K+] and transepithelial potential (Vt) during endolymph formation. While mature Vt levels are almost immediately achieved, K+accumulates to reach a steady [K+] by day 5 in culture. Inhibition of sensory cell K+efflux enhances [K+] regardless of the blocker used (FM1.43, amikacin, gentamicin, or gadolinium). Targeting K+secretion with bumetanide partially and transiently reduces [K+], while ouabain application andKcne1deletion almost abolishes it. Immunofluorescence studies demonstrate that dark cells do not express Na-K-2Cl cotransporter 1 (the target of bumetanide) in cultured and young mouse utricles, while Na/K-ATPase (the target of ouabain) is found in dark cells and transitional cells. This global analysis of the involvement of endolymphatic homeostasis actors in the immature organ (1) confirms that KCNE1 channels are necessary for K+secretion, (2) highlights Na/K-ATPase as the key endolymphatic K+provider and shows that Na-K-2Cl cotransporter 1 has a limited impact on K+influx, and (3) demonstrates that transitional cells are involved in K+secretion in the early endolymphatic compartment.
An Essential Role for RAX Homeoprotein and NOTCH–HES Signaling inOtx2Expression in Embryonic Retinal Photoreceptor Cell Fate Determination
Authors: Muranishi Yuki , Terada Koji , Inoue Tatsuya , Katoh Kimiko , Tsujii Toshinori , Sanuki Rikako , Kurokawa Daisuke , Aizawa Shinichi , Tamaki Yasuhiro , Furukawa Takahisa
Published: November 2011

The molecular mechanisms underlying cell fate determination from common progenitors in the vertebrate CNS remain elusive. We previously reported that the OTX2 homeoprotein regulates retinal photoreceptor cell fate determination. WhileOtx2transactivation is a pivotal process for photoreceptor cell fate determination, its transactivation mechanism in the retina is unknown. Here, we identified an evolutionarily conservedOtx2enhancer of ∼500 bp, named embryonic enhancer locus for photoreceptorOtx2transcription (EELPOT), which can recapitulate initialOtx2expression in the embryonic mouse retina. We found that the RAX homeoprotein interacts withEELPOTto transactivateOtx2, mainly in the final cell cycle of retinal progenitors. Conditional inactivation ofRaxresults in downregulation ofOtx2expressionin vivo. We also showed that NOTCH–HES signaling negatively regulatesEELPOTto suppressOtx2expression. These results suggest that the integrated activity of cell-intrinsic and -extrinsic factors onEELPOTunderlies the molecular basis of photoreceptor cell fate determination in the embryonic retina.
Impact of phosphodiesterase 8B gene rs4704397 variation on thyroid homeostasis in childhood obesity
Authors: Grandone Anna , Perrone Laura , Cirillo Grazia , Di Sessa Anna , Corona Alberto Maria , Amato Alessandra , Cresta Nicoletta , Romano Tiziana , Miraglia del Giudice Emanuele
Published: November 2011

Context

Several studies demonstrated that obese children have higher TSH than normal-weight children. The polymorphism rs4704397 in the phosphodiesterase 8B (PDE8B) gene showed an association with TSH.

Objectives

i) To assess the effect of PDE8B on TSH in obese children; ii) to dissect the role of obesity degree in modulating this association; and iii) to stratify the individual risk to show hyperthyrotropinaemia according to PDE8B genotype.

Methods

Eight hundred and sixty-seven Italian obese children were investigated. Clinical data and thyroid hormones were evaluated and the PDE8B rs4704397 was genotyped.

Results

PDE8B A/A homozygous subjects showed higher TSH (P=0.0005) compared with A/G or G/G. No differences were found for peripheral thyroid hormones. Among A/A children, 22% had hyperthyrotropinaemia, compared with 11.6% of heterozygotes and 10.8% of G/G (P=0.0008). Consistently, A/A had an odds ratio (OR) to show abnormal TSH level of 2.25 (P=0.0004). Body mass index (BMI) appeared correlated with TSH (P=0.0001), but the strength of the effect of PDE8B on TSH was independent of BMI (P=0.1).

Children were subdivided into six groups according to obesity degree and genotypes. PDE8B A/A with BMI SDS above 3 had the highest OR (OR 2.6, P=0.0015) to have hyperthyrotropinaemia, whereas G/G with BMI SDS below 3 showed the lowest possibilities (OR 0.3, P=0.005).

Conclusions

We have shown: i) in obese children, PDE8B is associated with TSH; ii) the interaction between adiposity and PDE8B on TSH is not synergistic, but follows an additive model; and iii) impact of this association in the stratification of individual risk to have hyperthyrotropinaemia.
The utility of basal serum LH in prediction of central precocious puberty in girls
Authors: Pasternak Yehonatan , Friger Michael , Loewenthal Neta , Haim Alon , Hershkovitz Eli
Published: November 2011

Objective

The mainstay of distinction between prepubertal girls and girls who are suspected of having central precocious puberty (CPP) is based on gonadotropin measurements after a GnRH stimulation test to evaluate hypothalamic–pituitary–gonadal axis maturity. The objective of this study was to determine whether a single basal gonadotropin measurement carries a useful predictive value in verifying or refuting the diagnosis of CPP.

Design and methods

Basal serum LH and FSH were measured by a chemiluminescent immunometric assay in a cohort of girls who had been evaluated for CPP before and after GnRH stimulation test. Peak LH levels higher than 5 IU/l were considered a pubertal response.

Results

Eighty girls with suspected breast development before 8 years of age were enrolled to the study, out of whom 42 had CPP.

Low basal serum LH (≤0.1 IU/l) was sufficient to rule out the diagnosis of CPP in 94.7% of the 38 prepubertal girls; the sensitivity of basal LH levels for this purpose was only 64%. The basal FSH and the basal LH to FSH ratio achieved less efficient predictive value with 76 and 71% sensitivity and 73 and 86% specificity respectively.

Conclusion

A single basal LH measurement may be adequate to confirm but not to refute the presence of CPP in most of the girls who are evaluated for early pubertal signs.
Effect of the interaction between food state and the action of estrogen on oxytocinergic system activity
Authors: Lucio-Oliveira F , Franci C R
Published: November 2011

Increased plasma osmolality by food intake evokes augmentation of plasma oxytocin (OT). Ovarian steroids may also influence the balance of body fluids by acting on OT neurones. Our aim was to determine if estrogen influences the activity of OT neurones in paraventricular nucleus (PVN) and supraoptic nucleus (SON) under different osmotic situations. Ovariectomized rats (OVX) were treated with either estradiol (E2) or vehicle and were divided into three groups: group I was fedad libitum, group II underwent 48 h of fasting, and group III was refed after 48 h of fasting. On the day of the experiment, blood samples were collected to determine the plasma osmolality and OT. The animals were subsequently perfused, and OT/FOS immunofluorescence analysis was conducted on neurones in the PVN and the SON. When compared to animals which were fasted or fedad libitum, the plasma osmolality of refed animals was higher, regardless of whether they were treated with vehicle or E2. We observed neural activation of OT cells in vehicle- or E2-treated OVX rats refed after 48 h of fasting, but not in animals fedad libitumor in animals that only underwent 48 h of fasting. Finally, the percentage of neurones that co-expressed OT and FOS was lower in both the PVN and the SON of animals treated with E2and refed, when compared to vehicle-treated animals. These results suggest that E2may have an inhibitory effect on OT neurones and may modulate the secretion of OT in response to the increase of osmolality induced by refeeding.
Transcriptional Regulation inSaccharomyces cerevisiae: Transcription Factor Regulation and Function, Mechanisms of Initiation, and Roles of Activators and Coactivators
Authors: Hahn Steven , Young Elton T
Published: November 2011

Here we review recent advances in understanding the regulation of mRNA synthesis in Saccharomyces cerevisiae. Many fundamental gene regulatory mechanisms have been conserved in all eukaryotes, and budding yeast has been at the forefront in the discovery and dissection of these conserved mechanisms. Topics covered include upstream activation sequence and promoter structure, transcription factor classification, and examples of regulated transcription factor activity. We also examine advances in understanding the RNA polymerase II transcription machinery, conserved coactivator complexes, transcription activation domains, and the cooperation of these factors in gene regulatory mechanisms.
Delayed Acyclovir and Outcomes of Children Hospitalized With Eczema Herpeticum
Authors: Aronson Paul L. , Yan Albert C. , Mittal Manoj K. , Mohamad Zeinab , Shah Samir S.
Published: November 2011

OBJECTIVE:

To describe the epidemiology and outcomes of children hospitalized with eczema herpeticum and to determine the association with delayed acyclovir on outcomes.

PATIENTS AND METHODS:

This was a multicenter retrospective cohort study conducted between January 1, 2001, and March 31, 2010, of 1331 children aged 2 months to 17 years with eczema herpeticum from 42 tertiary care children's hospitals in the Pediatric Health Information System database. Multivariable linear regression models determined the association between delayed acyclovir therapy and the main outcome measure: hospital length of stay (LOS).

RESULTS:

There were no deaths during the study period. Staphylococcus aureus infection was diagnosed in 30.3% of the patients; 3.9% of the patients had a bloodstream infection. Fifty-one patients (3.8%) required ICU admission. There were 893 patients (67.1%) who received acyclovir on the first day of admission. The median LOS increased with each day delay in acyclovir initiation. In multivariable analysis, delay of acyclovir initiation by 1 day was associated with an 11% increased LOS (95% confidence interval [CI]: 3%–20%; P = .008), and LOS increased by 41% when acyclovir was started on day 3 (95% CI: 19%–67%; P < .001) and by 98% when started on day 4 to 7 (95% CI: 60%–145%; P < .001). Use of topical corticosteroids on day 1 of hospitalization was not associated with LOS.

CONCLUSIONS:

Delay of acyclovir initiation is associated with increased LOS in hospitalized children with eczema herpeticum. Use of topical corticosteroids on admission is not associated with increased LOS. The mortality rate of hospitalized children with eczema herpeticum is low.
The presence of methicillin-resistant Staphylococcus aureus on large pig breeding farms in Croatia
Authors: Habrun Boris , Račić Ivana , Beck Relja , Budimir Ana , Benić Miroslav , Kompes Gordan , Špičić Silvio , Cvetnić Željko
Published: November 2011

Methicillin-resistantStaphylococcus aureus(MRSA) have emerged worldwide and have become resistant to a variety of antibiotics. MRSA colonisation in pigs was first reported from the Netherlands in 2005, where pigs were implicated as a source of human MRSA infections (Voss et al., 2005). This paper presents the first report on the presence of MRSA on large pig breeding farms in Croatia, together with the determination of themecAgene, the results ofspatyping and susceptibility to commonly used antimicrobials. Dust samples (7–11 per farm) were collected from eight large pig farms in Croatia. Of the total 68 swabs, themecA gene was detected in 24 isolates growing on the MRSA agar. All isolates were resistant to oxacillin, tetracycline and streptomycin, and susceptible only to vancomycin, while 92% of the strains were susceptible to ciprofloxacin. Genotyping of the MRSA strains was performed byspatyping, and revealed t011 (n = 17), t034 (n = 5) and t1451 (n = 2). The results presented here predict that MRSA is present on a large number of pig farms in Croatia.
Optimization of productions of cellulolytic enzymes by Aspergillus niger using residue of mango a substrate
Authors: Santos Tamires Carvalho dos , Cavalcanti Ingrid Souza , Bonomo Renata Cristina Ferreira , Santana Nivio Batista , Franco Marcelo
Published: November 2011

The present paper analyses the effects of water activity (0.88, 0.94 and 0.97) and of fermentation time (24, 48, 72, 96 and 120 hours) on the kinetic activity of enzymes cellulolytic, produced during the solid state fermentation of waste from the improvement of mango, with the aid of fungus species Aspergillus niger. Solid state fermentation was carried out at 35°C inside a bacteriological incubator. The statistical results indicated that the best activity for enzyme CMCase was 7.26U g-1 after 74.51 hours of fermentation, whereas for enzyme FPase was 2.55U g-1 after 98.52 hours, both presenting best results in approximately 0.928 of water activity. Pareto charts have showed that fermentation time has greater effect over the activity of enzyme CMCase, while the water activity variable has greater effect over enzyme FPase activity. During fermentation the fungus synthesized the enzymes without the need of inductors other than mango residue and water.
Lab-scale periphyton-based system for fish culture
Authors: Cavalcante Davi de Holanda , Silva Suzete Roberta da , Pinheiro Paloma Damasceno , Martins Ádila da Cunha , Sá Marcelo Vinícius do Carmo e
Published: November 2011

The present research aimed to assess a lab-scale model to study periphyton-based systems for fish culture. Twenty-five liters plastic aquaria were stocked with three Nile tilapia, Oreochromis niloticus, juveniles (0.77±0.09g; 12 fish m-2) for 6 weeks in a 2x2 factorial design. Small plastic bottles were placed in some aquaria for periphyton development. Two feeding regimes were employed: "full-fed" (standard feeding rates were fully adopted) and "half-fed" (50% of standard feeding rates). Growth performance and limnological variables were observed in each aquarium. There werefive replicates per treatment. Fish have fed actively on periphyton, especially in the half-fed aquaria. The placement of periphyton bottles had no significant effects on the water quality variables, except by the gross primary productivity which became lower. Half-fed aquaria presented lower concentrations of ammonia (0.28-0.29mg L-1), nitrite (0.33-0.37mg L-1) and phosphorus (0.42-0.43mg L-1) than full-fed aquaria (0.57-0.60mg L-1; 0.75-0.77mg L-1; 0.67-0.70mg L-1, respectively). The final body weight of fish in half-fed aquaria with periphyton bottles (6.22±0.64g) was significantly higher than in aquaria without bottles (4.65±0.36g). Although the growth rate of fish was lower in the half-fed aquaria (4.27-4.72 vs. 5.29-5.61% BW day-1), survival was significantly higher when compared to the full-fed aquaria (93.3-100.0 vs. 80.0-83.4%). Only in the aquaria with periphyton the feed conversation ratio was improved by the feeding restriction regime.
Microstructure – macro property model proposal
Authors: Ozturk Ali Ugur , Onal Okan , Baradan Bulent
Published: November 2011

A relationship between the microstructure formation and compressive strength of cement mortars has been established within this study. Microstructure properties such as pore area ratio, total pore length, total dendrite length and average roundness of pore phases were determined by microstructural investigations. In addition, the hydrated part area, calcium hydroxide phase area and unhydrated part area ratios were calculated based on image analysis. Six parameters (pore area ratio, total pore length, total dendrite length, average roundness, hydrated part area ratio and unhydrated part area ratio) were correlated to the compressive strength values of different mixtures. Multiple linear regression investigations indicated that determination of only two parameters (total dendrite length and hydrated part area ratio) is sufficient enough to represent the relationship of microstructural formation–compressive strength confidently. This analysis indicates that the connected channel system of pore phase is more effective on strength than the amount of pore phase.
Influence of classical and modern superplasticisers on the chemical and rheological behaviour of oil well cement: a comparative study
Authors: Wahedi Yasser Al , Awayes Jafar , Bassioni Ghada
Published: November 2011

The need for cements with good workability for oil well drilling purposes makes a systematic study necessary in order to investigate different cement–admixture combinations. In the present study the superplasticising effect induced by third-generation polycarboxylates was benchmarked against conventional melamine-based superplasticisers on oil well cement. Two commercial superplasticisers were studied at five different concentrations. The hydration progress over time was analysed by way of monitoring the crystal growth using a scanning electron microscope. Infrared and 29Si solid state nuclear magnetic resonance spectra were measured. Rheological and surface tension studies were conducted at the early stages of hydration. The results show clearly that the third-generation polycarboxylate under investigation was superior in terms of better cement workability. This superiority was attributed to the multi-branched nature of this compound which induced sterical repulsion on the cement grain surface. Moreover, the superplasticiser–cement complexed phases were found to be thermodynamically unstable as evidenced by infrared and nuclear magnetic resonance spectra. Recommendations are made concerning the application of superplasticisers in the oil industry in order to enhance the performance of the drilling process.
Successful Application of MPD (Managed Pressure Drilling) for Prevention, Control, and Detection of Borehole Ballooning in Tight Gas Reservoir in Cuervito Field, Mexico
Authors: Ochoa A. , Acevedo O. , Nieto L. , Lambarria J. E. , Pérez H.
Published: November 2011

The design of the wells in Cuervito Field is generally composed of three casings, in order to access the highest yielding sands. Drilling operations are characterized by the presence of a balloning effect, causing the loss of circulation that occasionally difficult meeting the planned target for the well.

The balloning effect, breathing formation or phenomenon of loss and gain, is an elastoplastic behavior of the walls of a well that usually originates in impermeable formations. When circulating drilling fluids it creates an additional pressure that is commonly defined as the equivalent circulation density (ECD), which when imposed on the walls of the well, causes them to dilate. When circulation is stopped, the ECD decreases, the diameter of the hole shrinks along with the pressure, creating a flow return to the well. High temperatures also play a role in the balloning effect. The expansion and contraction of the holes in the Cuervito Field is highly remarkable.

In order to minimize the encountered problems and to optimize drilling operations, a series of steps were prepared in order to study Cuervito Field’s 16 wells. This study contains geological and geopressure information. As a result of this study two different options were encountered: (i) Adding an additional casing or (ii) An unconventional drilling technique.

The first alternative (adding an additional casing to the well) proved to be a more complex and less elegant solution when compared to the unconventional drilling technique.

The unconventional drilling technique known as Managed Pressure Drilling (MPD), enables the control of the annular pressure profile and monitors the bottom pressure limits in order to maintain them at a constant level, while minimizing drilling fluid loss and drilling downtime.

During the drilling of the well 17 of Cuervito Field the effect balloning was presented in large scale and was implemented a pilot project to evaluate the technique of MPD. The result was successful and was applied in the following three wells in the Field, achieving the elimination of the typical problems of the area.
Integrated Acoustic, Mineralogy, and Geomechanics Characterization of the Huron Shale, Southern West Virginia, USA
Authors: Franquet J. A. , Mitra Arijit , Warrington D. S. , Moos Daniel , Lacazette Alfred
Published: November 2011

Exploitation of unconventional shale gas reservoirs depends on successful hydraulic fracturing and horizontal drilling. Mineralogy, organic matter content, acoustic anisotropy, and in-situ stress all play an important role for well completion design. As part of a comprehensive site study of the Upper Devonian Huron shale, borehole acoustic and mineralogy logging data, in addition to conventional logs, were acquired in a vertical well prior to hydraulic fracturing and microseismic monitoring of a series of laterals drilled from the same location. The acoustic data was processed for compressional wave, cross-dipole shear, Stoneley-derived horizontal shear, radial velocity variations, and borehole Stoneley reflectivity indicators. The cross-dipole anisotropy and the near-well radial slowness variations provided information about intrinsic anisotropy and stress sensitivity to determine the source of dipole-mode anisotropy. Significant transverse acoustic anisotropy was detected and used to obtain vertical and horizontal dynamic elastic properties. The mineralogy and petrophysical analysis were used to generate a micromechanical constitutive model to reproduce numerically the laboratory stress-strain behavior of the rock, from which quasi-static mechanical properties were determined. These were calibrated against triaxial tests on core samples from an offset well, and the vertical and horizontal static elastic rock properties were used to estimate the vertical variation of the horizontal stress. The resulting stress profile, along with accurate mineralogy and petrophysical analysis, provides important information to select the best vertical locations of lateral wells and to identify natural fracture barriers.
Coupled Geomechanical Modeling for Underground Coal Gasification
Authors: Deng Hui , Chen Zhangxin , Li Daiming
Published: November 2011

Simulation of underground coal gasification (UCG) is an integrated approach involving a Thermo-Hydro-Chemical-Mechanical process (THCM). The key is to understand the surface subsidence in the UCG process associated with the cavity growth and roof rock collapse during the coal seam combustion. However, the interaction between the mass transports and thermal-mechanical induced cavity and spalling cannot be fully captured by a conventional flow simulator without coupling geomechanics.

The literature has documented numerous methods of modeling the coupled Thermal-Chemical-Geomechanical process for UCG. The objective of this paper is to summarize the current research status and future developments of coupled geomechanical modeling approach for the UCG process, followed by a case study. Geochemistry and chemical reactions are modeled in the thermal reservoir simulator with a well-defined Controlled Retraction Injection Point (CRIP) configuration. A modular coupling approach is utilized in which geomechanical module calculates the changing of the stress and strain due to the changing of pressure and temperature, updating the porosity and permeability simultaneously. Finally, surface subsidence is investigated and limitations are also identified for future development.
Geomechanical Simulation of Caprock Performance for a Proposed, Low Pressure, Steam-Assisted Gravity Drainage Pilot Project
Authors: Uwiera-Gartner M. M. , Carlson M. R. , Walters D. , Palmgren C. T.
Published: November 2011

For oil sands assets having bitumen resources located near the ground surface, geomechanical assessments of caprock performance during steam-assisted gravity drainage (SAGD) operations have become increasingly important. These assessments need to determine and demonstrate whether the caprock can effectively withstand the induced stress and strain loadings from the SAGD operation throughout the life of the development.

The importance of caprock integrity for SAGD developments was realized following the loss of caprock containment at the Total E&P Canada Ltd., Joslyn Creek SAGD project in 2006. In light of this failure, the Alberta Energy Resources Conservation Board (ERCB) stipulated a series of response activities to address caprock integrity, including the requirement that pilot and commercial SAGD projects in Alberta need to conduct a geomechanical assessment of caprock integrity as part of the application process.

The authors completed a geomechanical simulation study of the Clearwater Formation caprock performance at a proposed, shallow, low pressure, SAGD (LP-SAGD) pilot project located southeast of Fort McMurray, Alberta, Canada. For this investigation, a 3D, coupled, reservoir and geomechanical simulation was conducted forecasting 10 years of asset response to the maximum operating pressure of 1,000 kPaa. The geomechanical response of the caprock to temperature changes, increased pore pressure and the induced stress and strain fields from the steam chamber was simulated as part of the caprock integrity assessment for the pilot project.

This paper presents the results of this simulation study and the uncertainties and risks associated with evaluating caprock containment of SAGD operations using numerical methods. The results of key geomechanical parameters, such as minimum principal effective stress, shear stress level, factor of safety and surface displacement are presented. A summary of the post-failure analyses of caprock containment at the Joslyn Creek SAGD project is presented.
Upscaling THAI: Experiment to Pilot
Authors: Greaves M. , Dong L. L. , Rigby S. P.
Published: November 2011

Numerical simulation of the insitu combustion process is complicated by sharp gradients, with different temporal and special regimes applying to the reaction front and diffusional transport. It is not possible to achieve fine scale solutions at field scale in a reasonable time, owing to the onerous computer requirements. Instead, grid coarsening procedures were used. Simulation solutions were obtained for a homogeneous reservoir section of the THAI® field pilot, near Conklin, Alberta, Canada. The reservoir model did not include an interbedded shale layer, or bottom water layer, and the study therefore represents a non-optimal, first stage simulation of the THAI process, prior to incorporating more reservoir complexities. The results show that the process is inherently stable over a six year operating period, since there was no oxygen in the produced gas. High temperatures are generated in the narrow combustion front zone (900 °C) but 60 m ahead the temperature is 500 – 600 °C. Rapid desaturation of reservoir water takes place ahead of the combustion front, allowing combustion gases to enter into the colder bitumen layers, thereby creating some oil mobility. Of particular significance, is the existence of a narrow, high saturation, Steam Zone, extending to more than 15 m, and up to 30 m during later stages of production. The steam zone propagates at up three times faster than that of the combustion front. Also, the Mobile Oil Zone (MOZ) is very significant characteristic of the THAI process throughout the whole production period. However, the temperature in the MOZ, close to the horizontal producer well, is quite low, around 150–180 °C. The oil recovery factor was approximately 60 % in the zone swept by the gas-steam front. Oil production peaked at 69 m3/day rate, averaging 350 barrrels per day for the single well pair.
Completion Evaluation of the Eagle Ford Formation with Heterogeneous Proppant Placement
Authors: Viswanathan A. , Altman R. , Oussoltsev D. , Kanneganti K. , Xu J. , Grant D. , Indriati S. , Peña A. , Loayza M. , Kirkham B. , Rhein T.
Published: November 2011

Since the initial success of multi-stage fracturing in horizontal laterals in the Eagle Ford Shale, multiple completion techniques have been implemented to optimize productivity. This paper discusses completion practices being followed in the Hawkville field, encompassing La Salle and McMullen counties in south Texas. While slickwater treatments provided the initial successes in the dry gas areas of the Eagle Ford, hybrid and channel fracturing treatments quickly showed improved, if not at least equal success in the wet gas areas while utilizing significantly less fluid and proppant volumes. The challenge has been to determine an optimum balance between the various completions parameters to increase production with less cost.

Optimization of Eagle Ford stimulation techniques became the most important objectives for completion and production engineers over the last two years, since the first horizontal multi-stage well was completed in the Hawkville field. Fracturing fluid systems, treatment rates, proppant types and concentrations along with completion details such as number of clusters, number of stages, and perforation intervals in horizontal laterals created a large number of variables impacting production for any operator. Implementation of any technology requires proper evaluation metrics that minimize geology, petrophysical and completion uncertainties. This paper describes the evaluation process of a novel stimulation technology – channel fracturing based on a heterogeneous proppant placement technique, and its comparison to existing conventional slickwater and hybrid stimulation treatments. The focus will be on the evaluation of in-situ conditions, challenges and production evaluation of different completion techniques using the following methodologies: normalized production comparison, productivity index analysis, neural network trained self-organizing maps and numerical simulations.

The initial production (IP) of the wells completed with the channel fracturing technique was 32–37% better, compared to offset conventional slickwater and hybrid wells. A detailed evaluation of horizontal well performance is described in this paper, based on statistical approaches and reservoir modeling. The combination of two evaluation techniques substantiates the statement that the incorporation of the channel fracturing technology as part of the completion design had a positive impact for the stimulation of wells in the Eagle Ford formation.
Reactive Thermal Reservoir Simulation: Hydrogen Sulphide Production in SAGD
Authors: Kapadia Punitkumar R. , Wang Jacky , Kallos Michael S. , Gates Ian D.
Published: November 2011

In SAGD, steam is injected into a bitumen bearing oil sands formation. Steam temperature ranges from about 200 to 260°C and at these temperatures, bitumen undergoes aquathermolysis yielding acid gases such as hydrogen sulphide and carbon dioxide. SAGD simulation models in the literature often account for spatial heterogeneity of the geology and oil composition and heat transfer, multiphase flow, gas solubility effects, and viscosity variations with temperature, however, none account for the chemistry of SAGD. Here, we consider aquathermolysis reactions to understand the reactive zones in the SAGD process and how the process generates acid gases via aquathermolysis. The results show that SAGD is both a physical and chemical-reactive process.