bluuebunny/crossref_metadata_2025 huggingface dataset:
Estrogen receptor positive breast cancers in BRCA1 mutation carriers: clinical risk factors and pathologic features
Authors: Tung Nadine , Wang Yihong , Collins Laura C , Kaplan Jennifer , Li Hailun , Gelman Rebecca , Comander Amy H , Gallagher Bridget , Fetten Katharina , Krag Karen , Stoeckert Kathryn A , Legare Robert D , Sgroi Dennis , Ryan Paula D , Garber Judy E , Schnitt Stuart J
Published: February 2010

Introduction

Most breast cancers that occur in women with germline BRCA1 mutations are estrogen receptor-negative (ER-) and also typically lack expression of progesterone receptor (PR) and HER2 overexpression. We undertook a study to assess the clinical factors that predict for an estrogen receptor positive (ER+) breast cancer in BRCA1 mutation carriers and to characterize the pathologic features of these tumors.

Methods

Clinical characteristics of BRCA1 carriers with 58 ER+ and 114 ER- first invasive breast cancers were compared. Pathologic features of BRCA1 ER+ cancers were compared to those of BRCA1 ER- cancers and to age-matched ER+ sporadic cancers.

Results

BRCA1 carriers aged ≥ 50 at diagnosis of first invasive breast cancer were more likely to have an ER+ cancer compared to those aged < 50 (57% vs 29%, P = 0.005). ER+ BRCA1 cancers were less likely than ER- BRCA1 cancers to have "BRCA-associated" features such as high mitotic activity, geographic necrosis/fibrotic focus, and pushing margins (RR 0.06, 0.22, 0.24; P < 0.001, 0.02, 0.03 respectively). When compared to sporadic ER+ cancers, ER+ BRCA1 cancers were more often of invasive ductal type (RR 2.4, P = 0.03), with a high mitotic rate (RR 5.0, P = 0.006) and absent or mild lymphocytic infiltrate (RR 10.2, P = 0.04).

Conclusions

BRCA1 carriers who are older at first breast cancer diagnosis are more likely to have ER+ tumors than younger BRCA1 carriers. These ER+ cancers appear pathologically "intermediate" between ER- BRCA1 cancers and ER+ sporadic breast cancers raising the possibility that either some ER+ BRCA1 cancers are incidental or that there is a unique mechanism by which these cancers develop.
Time-lapse seismic monitoring of CO2 injection into a depleted gas reservoir—Naylor Field, Australia
Authors: Urosevic Milovan , Pevzner Roman , Kepic Anton , Wisman Putri , Shulakova Valeria , Sharma Sandeep
Published: February 2010

The CO2CRC Otway Project conducted under the Australian Cooperative Research Centre for Greenhouse Gas Technologies is the first of its kind, where [Formula: see text] is injected into a depleted gas reservoir. The use of depleted gas fields for [Formula: see text] storage and or enhanced gas recovery is likely to become globally adopted. Therefore, the CO2CRC project provides important experience for monitoring under these conditions. However, injection of [Formula: see text] into a depleted gas reservoir (residual gas saturation zone in this case) does not present a favorable condition for the application of geophysical monitoring techniques, and particularly seismic methods.
Integrated reservoir, petrophysical, and seismic simulation of CO2 storage in coal beds
Authors: Zarantonello Sergio E. , Bevc Dimitri , Harris Jerry M.
Published: February 2010

In this paper, we present results of an integrated simulation study to assess the effectiveness of seismic imaging for monitoring [Formula: see text] sequestration. We considered two scenarios. In the first, injected [Formula: see text] remained confined within a shallow coal formation. In the second, the sequestered [Formula: see text] gas leaked through a semi-permeable shale layer to an overlying sand unit sealed above. In both scenarios, the [Formula: see text] injection process resulted in enhanced production of coal-bed methane. The reservoir and seismic simulations required the construction of 3D geologic and facies models, the estimations of seismic velocities based on rock physics correlations, and the development of geostatistical dual-porosity reservoir descriptions of the coal and overlying shale and sand units. We ran the 3D reservoir simulations with GEM 2008.10, an equation-of-state compositional reservoir simulator from Computer Modeling Group with the capability to model adsorption of injected [Formula: see text] in coal, desorption of [Formula: see text], and matrix shrinkage-swelling effects. The reservoir description was derived from a 3D geostatistical model of the Big George coal in the Powder River Basin. We used Batzle-Wang, Gassmann, and Mavko-Dvorkin-Mukerji relationships to incorporate the effects of mineral contents and changing reservoir properties on P-wave velocity. We built synthetic seismograms by simulating the propagation of acoustic waves through the 3D heterogeneous media, and used reverse time migration to create 3D seismic images corresponding to the state of the reservoir at the beginning and end of ten years of [Formula: see text] injection. The resulting seismic images clearly identified the regions of [Formula: see text] gas saturation, closely matching the gas-saturation profiles predicted by the reservoir simulator. Further research will be necessary to fine-tune an integrated reservoir simulation, rock physics modeling, and seismic imaging workflow to provide highly advanced imaging, monitoring, and verification capabilities for [Formula: see text] sequestration. This study is a first step toward this goal.
Integrating velocity measurements in a reservoir rock sample from the SACROC unit with an AVO proxy for subsurface supercritical CO2
Authors: Purcell Christopher , Mur Alan , Soong Yee , McLendon T. Robert , Haljasmaa Igor V. , Harbert William
Published: February 2010

One of the most promising methods proposed to mitigate global [Formula: see text] and one that is useful in enhanced oil recovery is carbon sequestration, a process in which [Formula: see text] is pressurized and injected into geologic formations. A technical challenge surrounding the geologic sequestration of [Formula: see text] is tracking the movement of the fluids pumped underground. Monitoring, verification, and accounting activities related to [Formula: see text] storage are important for assuring that any sequestered [Formula: see text] does not escape to the surface and can be considerably aided by reflection seismic-based detection methods. Through the use of lab-scale velocity measurements under in-situ conditions, combined with multiple 3D reflection seismic surveys, we hope to effectively track the movements of [Formula: see text] after injection.
The Effect of Dietary Protein on Intestinal Calcium Absorption in Rats
Authors: Gaffney-Stomberg Erin , Sun Ben-hua , Cucchi Carrie E. , Simpson Christine A. , Gundberg Caren , Kerstetter Jane E. , Insogna Karl L.
Published: February 2010

Increasing dietary protein intake in humans acutely increases urinary calcium. Isotopic absorption studies have indicated that, at least in the short term, this is primarily due to increased intestinal Ca absorption. To explore the mechanisms underlying dietary protein’s effect on intestinal Ca absorption, female Sprague Dawley rats were fed a control (20%), low (5%), or high (40%) protein diet for 7 d, and Ca balance was measured during d 4–7. On d 7, duodenal mucosa was harvested and brush border membrane vesicles (BBMVs) were prepared to evaluate Ca uptake. By d 7, urinary calcium was more than 2-fold higher in the 40% protein group compared with control (4.2 mg/d vs. 1.7 mg/d; P < 0.05). Rats consuming the 40% protein diet both absorbed and retained more Ca compared with the 5% protein group (absorption: 48.5% vs. 34.1% and retention: 45.8% vs. 33.7%, respectively; P < 0.01). Ca uptake was increased in BBMVs prepared from rats consuming the high-protein diet. Maximum velocity (Vmax) was higher in the BBMVs prepared from the high-protein group compared with those from the low-protein group (90 vs. 36 nmol Ca/mg protein · min, P < 0.001; 95% CI: 46–2486 and 14–55, respectively). The Michaelis Menten constant (Km) was unchanged (2.2 mmvs. 1.8 mm, respectively; P = 0.19). We conclude that in rats, as in humans, acute increases in protein intake result in hypercalciuria due to augmented intestinal Ca absorption. BBMV Ca uptake studies suggest that higher protein intake improves Ca absorption, at least in part, by increasing transcellular Ca uptake.
Vasotocin/V2-Type Receptor/Aquaporin Axis Exists in African Lungfish Kidney but Is Functional Only in Terrestrial Condition
Authors: Konno Norifumi , Hyodo Susumu , Yamaguchi Yoko , Matsuda Kouhei , Uchiyama Minoru
Published: February 2010

The vasopressin/vasotocin (VT)-V2-type receptor (V2R)-aquaporin (AQP)-2 axis plays a pivotal role in renal water reabsorption in tetrapods. It is widely thought that this axis evolved with the emergence of the tetrapods, reflecting a requirement of water retention in terrestrial environment. Here we report that lungfish, the closest living relatives of tetrapods, already possess a system similar to the VT-V2R-AQP2 axis in the kidney, but the system is functional only in the terrestrial estivating condition. We cloned a novel AQP paralogous to AQP0. The water permeability of Xenopus oocytes was increased by injection with the AQP cRNA and was further facilitated by preincubation with cAMP. In the kidney of estivating lungfish, the AQP protein was localized on the apical plasma membrane of the late distal tubule and was colocalized with basolateral V2R. By contrast, we found only little expression of the AQP mRNA and protein in the kidney of lungfish in aquatic condition. The expression levels of mRNA and protein were dramatically increased during estivation and decreased again by reacclimation of estivating lungfish to water. The AQP mRNA levels positively correlated with the VT mRNA levels in the hypothalamus, suggesting that the AQP exerts tubular antidiuretic action under control of VT. Because the tetrapod AQP2/AQP5 lineage is considered to be evolved from duplication of an AQP0 gene, the paralogous AQP0 in the lungfish probably represents ancestral molecule for tetrapod AQP2.
An Inflammatory Gene-Expression Fingerprint in Monocytes of Autoimmune Thyroid Disease Patients
Authors: van der Heul-Nieuwenhuijsen Leonie , Padmos Roos C. , Drexhage Roosmarijn C. , de Wit Harm , Berghout Arie , Drexhage Hemmo A.
Published: February 2010

Context: In monocytes of patients with autoimmune diabetes, we recently identified a gene expression fingerprint of two partly overlapping gene clusters, a PDE4B-associated cluster (consisting of 12 core proinflammatory cytokine/compound genes), a FABP5-associated cluster (three core genes), and a set of nine overlapping chemotaxis, adhesion, and cell assembly genes correlating to both PDE4B and FABP5.

Objective: Our objective was to study whether a similar monocyte inflammatory fingerprint as found in autoimmune diabetes is present in autoimmune thyroid disease (AITD).

Design and Patients: Quantitative PCR was used for analysis of 28 genes in monocytes of 67 AITD patients and 70 healthy controls. The tested 28 genes were the 24 genes previously found abnormally expressed in monocytes of autoimmune diabetes patients plus four extra genes found in whole-genome analysis of monocytes of AITD patients reported here.

Results: Monocytes of 24% of AITD and 50% of latent autoimmune diabetes of adults (LADA) patients shared an inflammatory fingerprint consisting of the set of 24 genes of the PDE4B, FABP5, and overlapping gene sets. This study in addition revealed that FCAR, the gene for the Fcα receptor I, and PPBP, the gene for CXCL7, were part of this proinflammatory monocyte fingerprint.

Conclusions: Our study provides an important tool to determine a shared, specific proinflammatory state of monocytes in AITD and LADA patients, enabling further research into the role of such proinflammatory cells in the failure to preserve tolerance in these conditions and of key fingerprint genes involved.
Lost in translation: reviewing the role of the discharge liaison nurse in Wales
Authors: Chandler Lynda , Wyatt Matt , Roberts Iain
Published: February 2010

In Wales, the National Leadership and Innovation Agency in Healthcare (NLIAH) Change Agent Team (CAT) has found that its service improvement methodology of Communities of Practice (CoP), where motivated frontline staff in health and social care come together to share issues and develop solutions to mutual problems, is a highly effective and informative tool. Health and social care organizations in Wales are in the process of working to develop processes and solutions to remedy the challenges they have over patients with long lengths of stay. This article shows how by speaking to the frontline staff, whose role it is to help people whose discharge is likely to be complex or problematic, they often have most insight into the solutions required to alleviate the situation. The learning in this article is that there is no one solution to improve the discharge process; however there are a number of small changes and improvements required, which if done consistently can have a significant impact. The findings here have been shared with Welsh government policy leads and health and social care executive teams to inform their planning and actions on how to resolve the challenge of reducing length of stay.
Cost and Impact of a Quality Improvement Programme in Mental Health Services
Authors: Beecham Jennifer , Ramsay Angus , Gordon Kate , Maltby Sophie , Walshe Kieran , Shaw Ian , Worrall Adrian , King Sarah
Published: February 2010

Objective

To estimate the cost and impact of a centrally-driven quality improvement initiative in four UK mental health communities.

Methods

Total costs in year 1 were identified using documentation, a staff survey, semi-structured interviews and discussion groups. Few outcome data were collected within the programme so thematic analysis was used to identify the programme's impact within its five broad underlying principles.

Results

The survey had a 40% response. Total costs ranged between £164,000 and £458,000 per site, plus staff time spent on workstreams. There was a very hazy view of the resources absorbed and poor recording of expenditure and activity. The initiative generated little demonstrable improvements in service quality but some participants reported changes in attitudes.

Conclusions

Given the difficult contexts, short time-scales and capacity constraints, the programme's lack of impact is not surprising. It may, however, represent a worthwhile investment in cultural change which might facilitate improvements in how services are delivered.
Accountability of Foundation Trusts in the English Nhs: Views of Directors and Governors
Authors: Dixon Anna , Storey John , Rosete Arturo Alvarez
Published: February 2010

Objectives

To map and describe the formal accountability relationships of foundation trusts in England and to explore the interpretations of these relationships by the key actors.

Methods

Documentary analysis and interviews with chief executives, chairs, directors and governors in six acute trusts and two Strategic Health Authorities.

Results

Although vertical accountability to the Department of Health (via Strategic Health Authorities) has, in formal terms, been removed some foundation trusts continue to be held to accountability by Strategic Health Authorities, albeit informally. Directors of foundation trusts perceive strong accountable to their regulator, Monitor, particularly for financial performance, but there is some confusion about where accountability for quality of care rests. Horizontal lines of accountability to the local population (through Local Involvement Networks and local government Overview and Scrutiny Committees) remain weak.

Conclusions

Contrary to the major policy objectives of giving greater autonomy to foundation trusts and making them more accountable to the local population, they continue to look towards the Department of Health rather than to the local population and its representatives. The accountability of foundation trusts needs to be simplified, clarified and strengthened.
Patients' and Staffs' Experiences of an Automated Telephone Weather Forecasting Service
Authors: Cooper Richard , O'Hara Rachel
Published: February 2010

Objectives

Patients with chronic obstructive pulmonary disease (COPD) have recently been offered severe weather warnings and medication reminders using an automated telephone service and interactive voice recognition technology. Our aim was to explore patients' and health care staffs' perceptions and experiences of the technologies, their contribution to the management of COPD and implementation issues.

Methods

Qualitative semi-structured telephone interviews were undertaken with 18 patients and six staff from five primary care centres in the Bradford area, England. Interview transcripts were thematically analysed.

Results

Patients considered the telephone service was an appropriate way to deliver information but there was some variation in perceived usefulness. Many patients praised the service, valuing reassurance and medication reminders, but others were indifferent and even critical. Criticism tended to reflect scepticism over the reliability of weather forecasts information rather than the automated telephone service itself. There was limited impact on the management strategies of patients apart from some patients ordering medication. Primary care staff considered the service a success but some felt that it lacked participation by hard-to-reach groups (non-English speaking, mild COPD patients). Our concerns about the resource implications of successful implementation were also raised.

Conclusions

An automated telephone service was generally acceptable to patients but changes in COPD management were limited, possibly because the patients already had a good understanding of their condition and self-management strategies. Implications for practice include the need for strategies to target hard-to-reach groups which may need more resources.
Patient Information Websites
Authors: Wright Kath , Harden Melissa , Light Kate , Stirk Lisa , Misso Kate
Published: February 2010

Patient information websites have become one of the main means of providing advice and information to individuals. The range of topics covered and the reliability of the information provided means that they can also be a valuable resource to practitioners and researchers. We first reviewed patient information websites in 2003 and this column updates that review. One of the developments since then is that information is now being presented using visual resources, such as podcasts and video clips, as well as text.

If you would like to alert readers to useful web pages or suggest topics for this column, please send details to:
Adverse Events in Randomized Trials; Hepatitis Caused by Transdermal Medication for Alzheimer Disease; Mycophenolate Mofetil–Induced Colitis in Children; Severe Apnea in Infant Caused by Lamotrigine in Breast Milk; Aripiprazole-Associated Paroxysmal Supraventricular Tachycardia; Three Cases of Severe Hepatic Impairment Caused by Erlotinib
Authors: Shuster Joel
Published: February 2010

The purpose of this feature is to heighten awareness of specific adverse drug reactions (ADRs), discuss methods of prevention, and promote reporting of ADRs to the US Food and Drug Administration's (FDA's) MedWatch program (800-FDA-1088). If you have reported an interesting, preventable ADR to MedWatch, please consider sharing the account with our readers.
Dolasetron: Spinal Opioid-Related Pruritus
Authors: Generali Joyce A. , Cada Dennis J.
Published: February 2010

This Hospital Pharmacy feature is extracted from Off-Label Drug Facts, a quarterly publication available from Wolters Kluwer Health. Off-Label Drug Facts is a practitioner-oriented resource for information about specific drug uses that are unapproved by the US Food and Drug Administration. This new guide to the literature enables the health care professional or clinician to quickly identify published studies on off-label uses and determine if a specific use is rational in a patient care scenario. A summary of the most relevant data is provided, including background, study design, patient population, dosage information, therapy duration, results, safety, and therapeutic considerations. References direct the reader to the full literature for more comprehensive information before patient care decisions are made. Direct questions or comments regarding Off-Label Drug Uses to hospital pharmacy@drugfacts.com .
A Practical Approach to Medication Reconciliation by Pharmacists in a Community Hospital Emergency Department
Authors: Thomas Michael C.
Published: February 2010

Purpose

The purpose of this paper is to describe the process of medication reconciliation by an emergency department (ED) pharmacist.

The ED pharmacist has many opportunities to interact with patients. Medication reconciliation by a pharmacist helps ensure a complete and accurate list of medications is obtained and documented. The process can be broken down into 3 categories—database, validation, and documentation. The database and validation steps involve gathering and confirming information related to medications patients are taking. These are the most challenging and time-consuming steps. The database step involves gathering current and previous information about the patient and using clinical skills to ensure a patient's medical problems are adequately treated. Many times patients do not know their medications well enough to provide the necessary information. To overcome this barrier, calls to pharmacies, physician offices, and other health care facilities may be necessary. At times, the use of electronic drug information databases to show patients images of medications is necessary for validation. Standard questions have been developed that probe patients on medications commonly left off of medication lists. The documentation step completes the process because it demonstrates a complete and accurate medication list for the patient's next health care provider.

Conclusion

The process of medication reconciliation is more than a translation of a medication list. Clinical skills are often necessary to ensure medication reconciliation is performed accurately and completely. Following the process of database, validation, and documentation helps ensure optimal pharmaceutical care.
Supratherapeutic Response to Ezetimibe in a Statin Intolerant Patient
Authors: Ruisinger Janelle F. , Koerner Jessica M. , Backes James M. , Moriarty Patrick M.
Published: February 2010

A 56-year-old white man with hypertension and a strong family history of cardiovascular disease was referred to a lipid-specialty clinic secondary to a statin intolerance (ie, myalgias) and dyslipidemia. The patient was initiated on ezetimibe 10 mg daily and experienced a supratherapeutic response. His baseline low-density lipoprotein cholesterol was reduced by 52% after 8 months of ezetimibe therapy, with no other explanation for the marked reduction. Recent studies have indicated a wide range of response to ezetimibe with different genetic variations. It is likely that this patient has a genetic variation that resulted in a hyperresponse to ezetimibe.
Colchicine Overdose—The Need for a Specific Antidote
Authors: Fagan Nancy L. , Wear Robert E. , Malesker Mark A. , Morrow Lee E. , Schuller Dan
Published: February 2010

Purpose

To report the case of a colchicine overdose to highlight current limitations in the treatment of this toxicologic emergency.

A 23-year-old man was admitted to the intensive care unit (ICU) after attempting suicide via polypharmacy ingestion, which included 80 to 100 colchicine 0.6 mg tablets (approximately 0.9 mg/kg of body weight). He was taken to the emergency department where gastric decontamination was initiated. Because attempts to obtain a colchicine-specific antibody fragment (Fab) were unsuccessful, only supportive therapies were provided throughout his hospitalization. Over the course of several days, the patient experienced the 3 separate evolutionary phases of colchicine toxicity ultimately leading to multiple organ failure and hemodynamic collapse, and death.

Conclusion

Acute colchicine intoxication is a rare, but potentially life-threatening event. Although 1 case report demonstrated the successful use of a colchicine-specific Fab fragment in the management of acute colchicine overdose, there is presently no commercially-available antidote for colchicine toxicity. Prompt recognition of the overdose, aggressive gastrointestinal decontamination, and supportive therapies directed at the multi-organ failure remain the standard of care.
Abusive supervision and subordinate supervisor‐directed deviance: The moderating role of traditional values and the mediating role of revenge cognitions
Authors: Liu Jun , Kwong Kwan Ho , Wu Long‐zeng , Wu Weiku
Published: February 2010

This study examined the link between abusive supervision and subordinate supervisor‐directed deviance by focusing on the moderating role of traditionality and the mediating role of revenge cognitions directed towards supervisors. The results of analysing 283 supervisor–subordinate dyads in six private electronic companies and 222 supervisor–subordinate dyads in two state‐owned oil and gas companies in the People's Republic of China showed that abusive supervision was positively related to revenge cognitions directed towards supervisors and to supervisor‐directed deviance. In addition, traditionality moderated the above relationships such that they were stronger among low traditionalists than among high ones, while revenge cognitions mediated the main effect of abusive supervision and the interactive effect of abusive supervision and traditionality on supervisor‐directed deviance.
Exploring the Concept of Team Situation Awareness in a Simulated Air Combat Environment
Authors: Sulistyawati Ketut , Wickens Christopher D. , Chui Yoon Ping
Published: February 2010

This paper evaluates team SA in air combat simulations. Team composition (in terms of diversity in team members' experience) as a factor that could influence team SA is analyzed in a study of 16 military fighter pilots performing simulated air combat missions in teams of two. The study used different measures to assess team SA, including SAGAT, self-appraisal, appraisal of teammate's state, and teamwork behavior and communication. The analysis of intercorrelations between different measures of team SA shows that they are not fully overlapping. The results show high association between good SA and team interaction as measured by information sharing and feedback, support, and backup behavior. The results also suggest the potential negative impact of diversity in team members' experience on team SA and interaction processes. Finally, we reveal that teams that perform well are characterized by individuals with high SA related to own task, well-calibrated confidence level, and good team interaction. On the other hand, teams that perform well do not necessarily do better in estimating their self-SA and teammate's status.
Slow Dynamics in Liquid Metals as Seen by QENS
Authors: Demmel Franz , Howells Spencer , Morkel Christoph , Pilgrim W.-C.
Published: February 2010

The quasielastic dynamics in liquid metals has been investigated by neutron scattering extensively during the past years. Precise measurements of the self-particle dynamics and the coherent quasielastic response provided conclusive evidence that the relaxation dynamics is governed by at least two processes. These two time scales in the correlation functions appear as two dynamical processes in their associated memory functions. One process shows a fast decay and is related to stochastic binary collisions. The second slow process stems from a non-linear coupling of slow collective modes. These slow density fluctuations arise mainly from the dynamics around the structure factor maximum. A rigorous treatment of these effects can be accomplished by mode coupling theory. A few selective experiments from monatomic metals are presented to demonstrate the influence of slow effects on the dynamics. Experiments and MD-simulations show a surprising good agreement with predictions of mode coupling theory on a quantitative level. The slow decay process appears to be related to structural arrest in the supercooled state and might indicate a link to the solidification process, starting deep in the liquid state. Accurate quasielastic neutron scattering experiments are still and will remain a fundamental pillar for elucidating the complex dynamics in the liquid state of metals.
Dynamics of Propylene adsorbed in Na-Y and Na-ZSM5 Zeolites: A QENS and MD Simulation Study
Authors: Sharma V. K. , Gautam S. , Mitra S. , Mukhopadhyay R.
Published: February 2010

Here we report dynamics of propylene (smallest asymmetric hydrocarbon) adsorbed in two different host systems – Na-Y and Na-ZSM5 zeolites as studied by quasielastic neutron scattering (QENS) techniques and molecular dynamics (MD) simulation techniques. MD simulation studies suggested that the rotational motion of propylene is much faster than the translation. Therefore, two different spectrometers were used to determine the translational and rotational contributions. Analysis of the QENS data (ΔE~200 μeV) revealed that the translational motion of propylene in Na-ZSM5 zeolite is a factor of 3 slower than that in Na-Y zeolite. This is consistent with the smaller void volume available in Na-ZSM5 zeolite as also the fact that the adsorption of propylene is stronger in Na-ZSM5 as compared to that in Na-Y zeolite as indicated in the Fourier Transformed Infra Red (FTIR) studies. This result is further corroborated by the MD simulation studies. It was found that the translation motion occurs at three time scales in both the systems, only one of which corresponds to that observed through the QENS measurements. To probe the faster rotational motion experiments were carried out on a Triple axis spectrometer with wider energy window (ΔE~3meV). The variation of the elastic incoherent structure factor (EISF) suggests that the observed QE broadening corresponds to isotropic rotational motion of propylene in both the hosts. Rotational diffusion coefficients of propylene molecules are found to be of the same order in both zeolites. Trajectories obtained from MD simulation corresponding to the rotational motion revealed that although on a large time scale, the rotation appears isotropic, but at short time scales the channel structure of the Na-ZSM5 restrict the rotation of propylene molecules. This is in contrast with propylene adsorbed in Na-Y zeolite where rotation remains isotropic even at short time scale. A comparison with other hydrocarbon-zeolite systems as studied by us is also presented here.
Dynamics in Clays - Combining Neutron Scattering and Microscopic Simulation
Authors: Malikova Natalie , Dubois Emmanuelle , Marry Virginie , Rotenberg Benjamin , Turq Pierre
Published: February 2010

Mobility of ions and water in clays is at the heart of their remarkable properties of water retention and ion-exchange. It has been addressed here using two microscopic techniques: neutron scattering and molecular dynamics simulations. Neutron scattering gives access exclusively to water dynamics in clays, due to the exceptional sensitivity of neutrons to H atoms. The data interpretation can be challenging, especially for natural clays such as montmorillonite, with inhomogeneous swelling characteristics. A great improvement is achieved with the use of synthetic materials, as demonstrated here on the case of synthetic (fluoro)hectorite. The standard analytical models for long-range diffusive motion, isotropic translation and its derivative, powder averaged two dimensional translation, have been used to interpret the neutron scattering data. They both agree on the order of magnitude for the diffusion coefficient of water in monohydrated and bihydrated clays, 10−10m2s−1and 10−9m2s−1respectively. While the two-dimensional nature of water diffusion in clays is seen clearly from molecular dynamics simulations, its signature in neutron scattering data is obscured by the powder-averaging of the signal. A novel method, based on a multi-resolution analysis of scattering functions from powder samples, allows never-the-less a clear determination of the dimensionality of water motion in the system. Extracting information on local water motion is difficult on the basis of neutron scattering data only. Various models for localised motion, rotation on a sphere or jump diffusion, have been proposed and used to interpret the observed neutron data, however their applicability is questionable in light of information from molecular dynamics simulations. Aside from aiding the interpretation of neutron scattering data, MD simulations are most valuable in providing information on the behaviour of ions in clays. MD estimates the interlayer ion coefficients as of the some order of magnitude as water, even if the details of ionic motion are strikingly different between the two ions considered here, Na+and Cs+. Further, MD has also allowed to address the topic of ion exchange between clay interlayers and bulk aqueous solution. The microscopic picture of water and ion motion in clays, emerging from neutron scattering and MD simulations, should be treated as a building block of the overall modelling of macroscopic transport in clays, the ultimate property of interest for many clay applications.
Study of Protein Dynamics vs. Amyloid Formation
Authors: Natali Francesca , Marasini Carlotta , Ferrando Riccardo , Gliozzi Alessandra
Published: February 2010

Protein fibril formation has been often associated to manifestation of serious and devastating amyloyd diseases, including Alzheimer and BSA. The main mechanism for the formation of amyloid fibrils is the accumulation of protein aggregates in body´s organs.In this paper, we try to compare the dynamical behaviour of two amyloidogenic proteins, the Insulin and the Myoglobin. Insulin has been chosen for its pharmacological extensive use in diabete´s therapy, while Myoglobin is used as control, since its dynamics is now largely known. The investigation has been performed through incoherent elastic neutron scattering over a wide temperature range. Our results suggest an enhanced stiffness of Insulin with respect to Myoglobin.
Monomer Dynamics in SDS Micellar Solution
Authors: Sharma V. K. , Verma Gunjan , Gautam S. , Hassan P. A. , Mitra S. , Mukhopadhyay R.
Published: February 2010

Monomer dynamics in sodium dodecyl sulfate (SDS) micellar solution at room temperature as studied by quasi elastic neutron scattering (QENS) technique is reported. The elastic incoherent structure factor (EISF) obtained from the analysis of QENS data suggests that the SDS chains perform uniaxial rotational diffusion along the long molecular axis. The rotation diffusion coefficient was found to decrease with the increase in the concentration of the surfactants. It is observed that on addition of electrolyte (0.8 M NaCl) the motion is arrested. Addition of salt is known to induce the growth in SDS micelles, here it is found to affect the dynamics of monomers also. This is due to the combined effect of closer packing of the monomers within the micelle and the tendency of amphiphilic molecules to stabilize due to the presence of electrolytes.
Dynamics of Caged Hydronium Ions and Super-protonic Conduction in (H3O)SbTeO6
Authors: Krzystyniak Maciej , Lopez-Anton Ricardo , Chatzidimitriou-Dreismann Aris , Lerch Martin , Fernández-Alonso Felix
Published: February 2010

The defect pyrochlores have become the focus of attention for the development and optimization of novel solid-state proton conductors as alternatives to costly polymer-based materials. A promising candidate is (H3O)SbTeO6, a super-proton conductor characterized by an outstanding conductivity of 10–1 S cm–1 at ambient conditions. The crystal structure of this compound has been known for some time yet, to date, the physical mechanism underpinning proton conduction has remained elusive. Structurally, (H3O)SbTeO6 consists of corner-shared (Sb/Te)O6 octahedra forming a cubic framework of three-dimensional interconnected cages partially occupied with hydronium H3O+ ions. These ions are connected to the inorganic framework by weak hydrogen bonds. In this work, we present the first characterization of this compound by means of quasielastic and inelastic neutron spectroscopy over a wide temperature range (T = 1.5–500 K), as well as by heat capacity measurements. Our results show that the onset of low-frequency stochastic motions of the hydronium moiety takes place around room temperature and persists up to the highest temperatures investigated. Unlike other inorganic proton conductors, these motions are effectively decoupled from vibrational motions at higher frequencies, as evidenced by the temperature dependence of the vibrational density of states. These findings have important implications for the exploitation of the defect pyrochlores as proton-conducting media for fuel-cell and gas-sensing applications.
Estrutura de um nitossolo vermelho latossólico eutroférrico sob sistema plantio direto, preparo convencional e floresta
Authors: Domingos Mausy Marchel Marques , Gasparetto Nelson Vicente Lovatto , Nakashima Paulo , Ralisch Ricardo , Tavares Filho João
Published: February 2010

Alterações estruturais causadas no solo pelos sistemas de manejo podem resultar em compactação e interferir no desenvolvimento radicular das culturas. Com o objetivo de avaliar os influxos do tipo de manejo sobre a estrutura do solo, por meio de métodos qualitativo (perfil cultural) e quantitativo (densidade), realizou-se um estudo em solo derivado do basalto, com textura argilosa a muito argilosa, no município de Maringá (PR), Terceiro Planalto Paranaense, coordenadas 23 º 29 ' S e 51 º 59 ' W, submetido aos sistemas de manejo convencional com sucessão de milho (Zea mays L. ) e soja (Glycine max); e plantio direto com rotação de trigo (Triticum spp.), milho (Zea mays L.), feijão (Phaseolus vulgaris), aveia-preta (Avena strigosa) e soja durante 20 anos. Próximo desses locais, selecionou-se área de floresta como testemunha. Amostras indeformadas foram coletadas a partir dos volumes homogêneos de solo, verificados na descrição do perfil cultural: duas amostras em solo sob floresta, duas em plantio direto e três amostras em solo com manejo convencional. A análise física associada às análises morfológicas das estruturas do solo para as profundidades de 0 a 20 cm e 20 a 40 cm permite concluir que: (a) o tipo de manejo do solo agrícola determina quantidades distintas de horizontes antrópicos; (b) a condição apresentada pelo volume estrutural infere a forma de exploração do solo pelas raízes; (c) os processos de compactação no solo sob manejo convencional ocorrem tanto em profundidade como em lateralidade; (d) o sistema plantio direto mostrou-se mais favorável do ponto de vista da qualidade estrutural; (e) o método do perfil cultural é eficiente em avaliações morfológicas do solo.
Estimation of water retention and availability in soils of Rio Grande do Sul
Authors: Reichert José Miguel , Albuquerque Jackson Adriano , Kaiser Douglas Rodrigo , Reinert Dalvan José , Urach Felipe Lavarda , Carlesso Reimar
Published: February 2010

Dispersed information on water retention and availability in soils may be compiled in databases to generate pedotransfer functions. The objectives of this study were: to generate pedotransfer functions to estimate soil water retention based on easily measurable soil properties; to evaluate the efficiency of existing pedotransfer functions for different geographical regions for the estimation of water retention in soils of Rio Grande do Sul (RS); and to estimate plant-available water capacity based on soil particle-size distribution. Two databases were set up for soil properties, including water retention: one based on literature data (725 entries) and the other with soil data from an irrigation scheduling and management system (239 entries). From the literature database, pedotransfer functions were generated, nine pedofunctions available in the literature were evaluated and the plant-available water capacity was calculated. The coefficient of determination of some pedotransfer functions ranged from 0.56 to 0.66. Pedotransfer functions generated based on soils from other regions were not appropriate for estimating the water retention for RS soils. The plant-available water content varied with soil texture classes, from 0.089 kg kg-1 for the sand class to 0.191 kg kg-1 for the silty clay class. These variations were more related to sand and silt than to clay content. The soils with a greater silt/clay ratio, which were less weathered and with a greater quantity of smectite clay minerals, had high water retention and plant-available water capacity.
Diagnostic techniques applied in geostatistics for agricultural data analysis
Authors: Borssoi Joelmir André , Uribe-Opazo Miguel Angel , Galea Rojas Manuel
Published: February 2010

The structural modeling of spatial dependence, using a geostatistical approach, is an indispensable tool to determine parameters that define this structure, applied on interpolation of values at unsampled points by kriging techniques. However, the estimation of parameters can be greatly affected by the presence of atypical observations in sampled data. The purpose of this study was to use diagnostic techniques in Gaussian spatial linear models in geostatistics to evaluate the sensitivity of maximum likelihood and restrict maximum likelihood estimators to small perturbations in these data. For this purpose, studies with simulated and experimental data were conducted. Results with simulated data showed that the diagnostic techniques were efficient to identify the perturbation in data. The results with real data indicated that atypical values among the sampled data may have a strong influence on thematic maps, thus changing the spatial dependence structure. The application of diagnostic techniques should be part of any geostatistical analysis, to ensure a better quality of the information from thematic maps.
Ácidos Húmicos em solo fertirrigado no Vale do São Francisco
Authors: Cunha Tony Jarbas Ferreira , Bassoi Luís Henrrique , Simões Marcelo Luiz , Martin-Neto Ladislau , Petrere Vanderlise Giongo , Ribeiro Paula Rose de Almeida
Published: February 2010

A aplicação de ácidos orgânicos, principalmente húmicos (AH), associada à adubação mineral e orgânica pode levar a alterações nas propriedades dos AH do solo. No Vale do São Francisco, o uso de ácidos orgânicos vem despertando o interesse de produtores que usam sistema de irrigação. Entretanto, não são conhecidas as modificações que podem ocorrer nas características das substâncias húmicas do solo quando são aplicados ácidos orgânicos associados à fertilização mineral e estercos. Os objetivos deste trabalho foram avaliar e caracterizar, por métodos espectroscópicos (UV-Vis, Infravermelho, Fluorescência e RPE), as possíveis mudanças qualitativas no AH extraído de solo fertirrigado com duas fontes de fertilizantes (orgânica e mineral), associadas à aplicação de ácidos orgânicos comerciais na cultura da goiabeira. O experimento foi conduzido na Embrapa Semiárido, em Petrolina - PE. Os tratamentos utilizados foram: F - fertirrigação com fertilizantes minerais (ureia, fosfato monoamônio, cloreto de potássio); FE - F + aplicação de 20 dm³/planta de esterco; FH - F + fertirrigação com 30 dm³ ha-1 de Codahumus 20®; FEH - fertirrigação mineral + aplicação de 20 dm³/planta de esterco + fertirrigação com 30 dm³ ha-1 de Codahumus 20®, e R- tratamento testemunha, sem adubação. A relação E4/E6 dos AH variou de 4,8 a 5,4 para os tratamentos FEH e F. Os dados obtidos por meio da espectroscopia FTIR sugerem mistura de características aromático-alifáticas, grande quantidade de grupos carboxílicos e menor número de grupos nitrogenados para os AH dos tratamentos FEH, FH e FE. Os valores obtidos do índice A465 variaram de 1,04 a 1,74, referentes aos AH dos tratamentos FEH e FE. Verificou-se uma concentração de radicais livres orgânicos no AH do tratamento FEH (2,66 spins g-1 10(17)) três vezes maior do que o AH do tratamento F (0,95 spins g-1 10(17)). O esterco foi o responsável pelo maior de policondensação e grau de humificação do ácido húmico dos tratamentos FE e FHE.
Distribuição de massa molecular de ácidos húmicos e promoção do crescimento radicular
Authors: Aguiar Natália de Oliveira , Canellas Luciano Pasqualoto , Dobbss Leonardo Barros , Zandonadi Daniel Basílio , Olivares Fábio Lopes , Façanha Arnoldo Rocha
Published: February 2010

Os ácidos húmicos (AH) estimulam diretamente vários processos fisiológicos que promovem o crescimento vegetal, especialmente do sistema radicular. O conhecimento da natureza química e do papel de AH na expressão de efeitos biofertilizantes e bioestimulantes é fundamental para o desenvolvimento de insumos biológicos à base de ácidos húmicos. O objetivo deste trabalho foi avaliar uma possível relação entre a distribuição de massa molecular aparente de AH isolados de vermicomposto e a magnitude de resposta na promoção do crescimento radicular. Para isso, foram obtidas subfrações (SF) dos AH por meio de cromatografia preparativa por exclusão de tamanho em gel de Sephadex G-50 (CGE). O processo preparativo foi validado pelo uso da cromatografia líquida de alta performance por exclusão de tamanho (HPSEC). As cinco frações obtidas foram testadas em diferentes concentrações (0; 0,0001; 0,001; 0,003; 0,005; e 0,01 mol L-1 de C) quanto à sua capacidade de estimular o crescimento radicular de plantas de Arabidopsis thaliana (ecótipo col. 4). Para plantas de milho (Zea mays hyb. UENF 506-6) foi utilizada a dose de 0,002 mol L-1 de C. O modelo quadrático descreveu a indução do crescimento radicular de Arabidopsis e a dose de AH, sendo 0,00511 mol L-1 de C o ponto de inflexão médio. Na concentração ótima, foi observada correlação inversa e significativa entre distribuição de massa molecular e indução do número de raízes laterais em Arabidopsis. No entanto, outros atributos, como área e comprimento radicular, não sofreram influência da massa molecular aparente. Em plântulas de milho, foi observado aumento no número de sítios de mitose e raízes laterais tanto no tratamento com AH como com suas subfrações. A atividade da H+-ATPase de membrana plasmática foi significativamente alterada pelo AH, porém não ocorreu o mesmo com todas as subfrações. A atividade de estimulação do crescimento radicular parece estar mais relacionada com a estrutura química das substâncias húmicas do que com a distribuição de massa molecular dos agregados húmicos.