bluuebunny/crossref_metadata_2025 huggingface dataset:
A Retrospective Correlation of Percutaneous Feeding Tube Stoma Length in Sitting and Supine Positions Compared With Body Mass Index
Authors: Steenblik Matthew , Hilden Kristen , Fang John C.
Published: March 2012

Background: Accurate knowledge of stoma tract length is important to prevent gastric ulcer formation, buried bumper syndrome, and peristomal leakage/infection. Current guidelines suggest 0.5–1.0 cm of play between the skin and external bolster. The aim of this study was to determine if stoma tract length changes from supine and sitting position and if this change is related to BMI. Methods: Patients undergoing percutaneous feeding tube change from November 2006 to September 2009 were enrolled. Correlations were made between BMI and stoma tract length in both sitting and supine positions. Results: Twenty‐eight patients (24 percutaneous endoscopic gastrostomy [PEG], 4 direct percutaneous jejunal feeding tube) were included; 19 (68%) were female. The mean ± SD stoma length was 3.6 ± 0.9 cm in the supine position and 4.9 ± 1.4 cm in the sitting position. The mean ± SD stoma length change from supine to sitting position was 1.53 ± 0.9 cm. Mean ± SD BMI was 21.2 ± 4.5 (range, 14.9–33.8). Stoma length in the supine position (r = 0.65, P = .0002) and sitting position (r = 0.6, P = .0009) was strongly correlated with BMI. Change in stoma tract length was correlated with BMI (r = 0.43, P = .02). Conclusion: Stoma tract length is strongly correlated with BMI in both the sitting and supine positions. PEG stoma tract length changes significantly from the supine and sitting position. To prevent complications, most patients should have a longer distance set between internal and external bolsters than is recommended.
Is the future of fluid power digital?
Authors: Scheidl Rudolf , Linjama Matti , Schmidt Stefan
Published: March 2012

This article presents digital fluid power as a new branch of fluid power which offers high potential for innovative solutions. The variety of digital concepts is quite large and digital concepts have long been successfully applied in low-power applications. Research and development is now becoming more intensive, being undertaken by several research groups and also more and more in industry. First applications will be brought to industry soon. A successful application requires new components, a sound understanding of system and new control principles.
Fault-tolerant control design for near-space vehicles based on a dynamic terminal sliding mode technique
Authors: Zhao Jing , Jiang Bin , Shi Peng , Gao Zhifeng , Xu Dezhi
Published: March 2012

In this paper, a fault-tolerant control scheme based on a second-order dynamic terminal sliding mode is proposed for a near-space vehicle attitude dynamical system in the presence of actuator faults, model parameter uncertainties and external disturbances. The principle of the proposed dynamic terminal sliding mode scheme is firstly introduced. Then, a near-space vehicle attitude faulty model with parameter uncertainty is established. Furthermore, two dynamic terminal sliding mode controllers are designed for the inner and outer loops. It is shown that the proposed algorithm can reduce chattering phenomenon and guarantee system stability and asymptotic state tracking. Finally, simulation results are provided to demonstrate the performance of the proposed fault-tolerant control scheme.
Seasonally laminated diatom-rich sediments from Dumont d’Urville Trough, East Antarctic Margin: Late-Holocene Neoglacial sea-ice conditions
Authors: Maddison Eleanor J , Pike Jennifer , Dunbar Robert
Published: March 2012

Laminated sediments are unique archives of palaeoenvironmental and palaeoceanographic conditions, recording changes on seasonal and interannual timescales. Diatom-rich laminated marine sediments are examined from Dumont d’Urville Trough, East Antarctic Margin, to determine changes in environmental conditions on the continental shelf from 1136 to 3122 cal. yr BP. Scanning electron microscope backscattered electron imagery (BSEI) and secondary electron imagery are used to analyse diatom assemblages from laminations and to determine interlamina relationships. Diatom observations are quantified with conventional assemblage counts. Laminae are primarily classified according to visually dominant species identified in BSEI and, secondarily, by terrigenous content. Nine lamina types are identified and are characterized by: Hyalochaete Chaetoceros spp. resting spores (CRS); CRS and Fragilariopsis spp.; Fragilariopsis spp.; Corethron pennatum and Rhizosolenia spp.; C. pennatum; Rhizosolenia spp.; mixed diatom assemblage; Stellarima microtrias resting spores (RS), Porosira glacialis RS and Coscinodiscus bouvet; and P. glacialis RS. Formation of each lamina type is controlled by seasonal changes in sea ice cover, nutrient levels and water column stability. Quantitative diatom assemblage analysis revealed that each lamina type is dominated by CRS and Fragilariopsis sea ice taxa, indicating that sea ice cover was extensive and persistent in the late Holocene. However the lamina types indicate that the sea ice regime was not consistent throughout this period, notably that a relatively warmer period, ~3100 to 2500 cal. yr BP, was followed by cooling which resulted in an increase in year round sea ice by ~1100 cal. yr BP.
Genetic Polymorphisms Influence Recovery from Traumatic Brain Injury
Authors: Weaver Starla M. , Chau Aileen , Portelli Jaclyn N. , Grafman Jordan
Published: March 2012

Traumatic brain injury (TBI) is a major public health concern in both civilian and military populations. Recently, genetics studies have begun to identify individual differences in polymorphisms that could affect recovery and outcome of cognitive and social processes following TBI. This review considers the potential for polymorphisms to influence six specific cognitive and social functions, which represent the most prominent domains of impairment following TBI: working memory, executive function, decision making, inhibition and impulsivity, aggression, and social and emotional function. Examining the influence of polymorphisms on TBI outcome has the potential to contribute to an understanding of variations in TBI outcome, aid in the triaging and treatment of TBI patients, and ultimately lead to targeted interventions based on genetic profiles.
Robust control of automotive engine using active engine mount
Authors: Fakhari Vahid , Ohadi Abdolreza
Published: March 2012

In this study, the effectiveness of an active engine mount in vibration suppression of a four-cylinder engine is evaluated. Two robust control algorithms, namely H2 and H∞ schemes, are employed to provide control input using accelerations of the engine body in the position of the mounts. In this regard, an accurate engine model is presented and the exciting active engine mount model is employed to design robust controllers. Derivation of equations of motion for an engine on the mounts is performed using Lagrange's and Newton–Euler equations. This derivation of equations has not been presented in any other study. In addition, unstructured uncertainties due to the unmodeled dynamics of the plant, actuator and sensors are considered. Using appropriate weighting functions, two robust control algorithms are designed. Robust stability and robust performance of the proposed controllers are evaluated using µ-analysis. The effectiveness of the proposed controllers, in the presence of sensor noise, in vibration suppression of the engine is evaluated. Results show that active mount with the designed robust controllers can improve the vibration behavior of the engine in the presence of sensor noise.
Survey of the feline leukemia virus infection status of cats in Southern Germany
Authors: Englert Theresa , Lutz Hans , Sauter-Louis Carola , Hartmann Katrin
Published: March 2012

Most studies that investigate the prevalence of infections with feline leukemia virus (FeLV) are based on the detection of p27 antigen in blood, but they do not detect proviral DNA to identify the prevalence of regressive FeLV infections. The aim of the present study was to assess the prevalence and status of FeLV infection in cats in Southern Germany. P27 antigen enzyme-linked immunosorbent assay (ELISA), anti-p45 antibody ELISA, DNA polymerase chain reaction (PCR) of blood and RNA PCR of saliva were performed. Nine out of 495 cats were progressively (persistently) infected (1.8%) and six were regressively (latently) infected (1.2%). Cats with regressive infections are defined as cats that have been able to overcome antigenemia but provirus can be detected by PCR. Twenty-two unvaccinated cats likely had abortive infections (regressor cats), testing FeLV antigen- and provirus-negative but anti-p45 antibody-positive. Most of the FeLV-vaccinated cats did not have anti-FeLV antibodies. Both progressive, as well as regressive infections seem to be rare in Germany today.
Comparison of two formulations of buprenorphine in cats administered by the oral transmucosal route
Authors: Bortolami Elisa , Slingsby Louisa , Love Emma J
Published: March 2012

This randomised, blinded, cross-over study investigated the ease of oral transmucosal administration of two formulations of buprenorphine using glucose as a control in 12 cats. The cats received three treatments: buprenorphine multi-dose, buprenorphine and the equivalent volume of glucose 5%. Ease of treatment administration, observation of swallowing, changes in pupil size, sedation, salivation, vomiting, behaviour and food intake were assessed. The data were analysed using MLwiN and multi-level modelling. Ease of administration of buprenorphine multi-dose was statistically different from glucose ( P <0.001), and the administration of all treatments became easier over the study periods. Swallowing was not statistically different between groups ( P >0.05). Mydriasis was evident after the administration of both formulations of buprenorphine. Sedation, salivation, vomiting, behavioural changes or in-appetence were not observed after any treatment. Cats tolerated oral transmucosal administration of glucose better than buprenorphine multi-dose, while buprenorphine administration was tolerated as well as glucose.
Impact modelling and analysis of the compliant legged robots
Authors: Bi Shu-Sheng , Zhou Xiao-Dong , Marghitu Dan B
Published: March 2012

The dynamics of the compliant legged robots are commonly characterized by the spring loaded inverted pendulum model. In this article, a new model is presented for the impact of the compliant legged robots. Compared with the spring loaded inverted pendulum model, the new model provides a means to take into account the factors such as the sliding of the terminal, the vibrations of the leg with distributed compliance and variation of the nonlinear contact force. The effectiveness of the model is validated by the finite element program LS-DYNA from the velocity and energy point of view. Based on the method used, the influences of the parameters, such as the incident angle, width, thickness and Young’s modulus of the flexible leg on the dynamic characteristics of the robot, are analysed. It is found that the post-impact vertical velocity of the robot decreases with the increasing incident angles, and increases approximately linearly with the width and thickness, while the variation of Young’s modulus of the flexible leg has little effects on it. The same is true of the energy loss ratio during the impact. All the parameters investigated are more intuitive than the stiffness described in the spring loaded inverted pendulum model and can be utilized directly for the optimization design and locomotion control of the compliant legged robots. In addition, the vibrations and multiple impacts can be predicted by the proposed model to reduce the energy loss.
Diagnostics of primary aldosteronism: is obligatory use of confirmatory tests justified?
Authors: Myśliwiec Janusz , żukowski Łukasz , Grodzka Anna , Piłaszewicz Agata , Drągowski Szymon , Górska Maria
Published: March 2012

Introduction:

Assessment of the renin-angiotensin-aldosterone system has been recently granted a much greater role in the evaluation of patients with arterial hypertension. There is no single test efficient in selection of patients for second-step etiological investigation.

Methods:

Altogether, 198 consecutive patients − 119 women (60%) and 79 men (40%) – hospitalized in years 2009–2011 at the Clinical Department of Endocrinology Medical University of Bialystok were diagnosed with primary aldosteronism. In each patient, plasma renin activity and plasma aldosterone concentration (basic and after 2 l NaCl infusion) were evaluated.

Results:

The percentage of patients with plasma aldosterone concentration ≥15 ng/ml was 53 and the percentage of patients with plasma renin activity ≤0.1 ng/ml/h was 20. The percentage of patients screened for primary aldosteronism in which the aldosterone:renin ratio exceeded consecutive cut-offs of 20, 30, 40 and 50 were respectively 57, 45, 34 and 29. Among 15 patients in which plasma aldosterone concentration after infusion of 2 l of saline was ≥6.5 ng/dl (8.6%), 13 (6.6%) were diagnosed with primary aldosteronism.

Conclusion:

The obligatory use of tests confirming autonomy of aldosterone secretion in patients screened for primary aldosteronism seems cost-effective in limiting the number of patients for further diagnosis.
Revisiting Truth or Triviality
Authors: Mitchell Gregory
Published: March 2012

Anderson, Lindsay, and Bushman (1999) compared effect sizes from laboratory and field studies of 38 research topics compiled in 21 meta-analyses and concluded that psychological laboratories produced externally valid results. A replication and extension of Anderson et al. (1999) using 217 lab-field comparisons from 82 meta-analyses found that the external validity of laboratory research differed considerably by psychological subfield, research topic, and effect size. Laboratory results from industrial–organizational psychology most reliably predicted field results, effects found in social psychology laboratories most frequently changed signs in the field (from positive to negative or vice versa), and large laboratory effects were more reliably replicated in the field than medium and small laboratory effects.
Reversal Without Remapping
Authors: Coutanche Marc N. , Thompson-Schill Sharon L.
Published: March 2012

The “cognitive revolution” in psychology is often framed as a departure from associationist principles rooted in animal learning research, yet it is clear that these principles have immediate relevance for contemporary questions in cognitive and social psychology. Intuitions about the consequences of learning procedures can easily be misleading, making these principles particularly important. To illustrate this point, we identified recent examples of studies applying a particular learning paradigm—response-reversal training—to the study of three different psychological problems (e.g., why objects in the right side of space are preferred to those in the left in right-handed people). The strategy of each study was to alter a typically encountered contingency once in the laboratory, in order to reverse a hypothesized learned response. Yet, contrary to intuitions, we demonstrate that behavior changes can be observed without the reversal of a prior association. Further, many different associative changes can underlie response reversals. We focus on these examples of response-reversal training, but our broader aim is to help connect the animal learning literature to problems in cognitive and social psychology in an effort to strengthen the inferences that might be drawn about learned associations in these contexts.
Fragmented Sleep, Fragmented Mind
Authors: van der Kloet Dalena , Merckelbach Harald , Giesbrecht Timo , Lynn Steven Jay
Published: March 2012

In psychopathology, dissociation typically refers to a disturbance in the normal integration of thoughts, feelings, and experiences into consciousness and memory. In this article, we review the literature on how sleep disturbances relate to dissociative symptoms and memory failure. We contend that this body of research offers a fresh perspective on dissociation. Specifically, we argue that dissociative symptoms are associated with a labile sleep–wake cycle, in which dreamlike mentation invades the waking state, produces memory failures, and fuels dissociative experiences. The research domain of sleep and dissociation can accommodate the dominant idea in the clinical literature that trauma is the distal cause of dissociation, and it holds substantial promise to inspire new treatments for dissociative symptoms (e.g., interventions that focus on normalization of the sleep-wake cycle). We conclude with worthwhile paths for further investigations and suggest that the sleep–dissociation approach may help reconcile competing interpretations of dissociative symptoms.
A review of ethical frameworks for the disclosure of individual research results in population-based genetic and genomic research
Authors: Budin-Ljøsne Isabelle
Published: March 2012

Individual research results from population-based genetic and genomic research are traditionally not disclosed to research participants. Current practices of non-disclosure are, however, being challenged by an increasing number of scientists, ethicists and policy-makers who make arguments in favour of disclosing at least individual results of potential health or lifestyle significance to research participants. Simultaneously, research participants are expressing greater interest in accessing their results. This article first provides an overview of main arguments for and against the disclosure of individual research results to research participants. Next, it discusses the need for a move from the current ethical framework under which researchers operate, which is rather protective of research participants and does not encourage disclosure, to a new ethical framework that would better cope with current developments within the field. Comparative analysis of existing and potential ethical frameworks favours implementation of an ethical framework aimed at enhancing the autonomy of research participants through the disclosure of individual research results. Finally, this article explores practical models of disclosure that could be used under such a new framework. A model of disclosure that takes into account the two key criteria of communicability of research results and the research participant’s preferences to determine which results to disclose is found to comply best with the selected ethical framework.
How safe are new medical devices?
Authors: Humphreys Stephen J.
Published: March 2012

In this article, I identify the peculiar challenges of current regulation in the UK to assess the safety of new medical devices. Not only is there a limited role for the regulatory authority in assessing their safety, but also no clinical investigation might be needed before many new devices can be marketed for use in populations across the European Union. As a lay member of a committee flagged to review research involving medical devices, I describe some of the difficulties we face in this regard as well as recent developments designed to raise regulatory standards.
Fragment-specific fixation for complex intra-articular fractures of the distal radius: results of a prospective single-centre trial
Authors: Gavaskar A. S. , Muthukumar S. , Chowdary N.
Published: March 2012

The goal was to evaluate the efficacy of 2.4 mm column-specific plating for intra-articular distal radius fractures. In total, 105 patients with AO type C distal radius fractures were operated on using the locking distal radius system, Synthes. Follow-up assessments including clinical (wrist and forearm range of motion, grip strength), radiological (articular step, radial length and inclination, volar tilt, and ulnar variance), and functional scores (Disabilities of the Arm, Shoulder, and Hand; Patient Rated Wrist Evaluation) were made at regular intervals until 1 year. Union was obtained in all patients. Articular surface was anatomically reconstructed in 74 patients (70.5%). Clinical and functional evaluation showed significant continuous improvements over the first year. C1 fractures had a better chance of anatomical reduction compared with C2 and C3 fractures. Fracture type, quality of reduction, and presence of degenerative changes did not show a significant effect on functional outcome scores. Column-specific fixation of the distal radius can achieve satisfactory results in complex intra-articular fractures.
Crystalline glucosamine sulfate in the management of knee osteoarthritis: efficacy, safety, and pharmacokinetic properties
Authors: Rovati Lucio C. , Girolami Federica , Persiani Stefano
Published: March 2012

Glucosamine is an amino monosaccharide and a natural constituent of glycosaminoglycans in articular cartilage. When administered exogenously, it is used for the treatment of osteoarthritis as a prescription drug or a dietary supplement. The latter use is mainly supported by its perception as a cartilage building block, but it actually exerts specific pharmacologic effects, mainly decreasing interleukin 1-induced gene expression by inhibiting the cytokine intracellular signaling cascade in general and nuclear factor-kappa B (NF-kB) activation in particular. As a whole, the use of glucosamine in the management of osteoarthritis is supported by the clinical trials performed with the original prescription product, that is, crystalline glucosamine sulfate. This is the stabilized form of glucosamine sulfate, while other formulations or different glucosamine salts (e.g. hydrochloride) have never been shown to be effective. In particular, long-term pivotal trials of crystalline glucosamine sulfate 1500 mg once daily have shown significant and clinically relevant improvement of pain and function limitation (symptom-modifying effect) in knee osteoarthritis. Continuous administration for up to 3 years resulted in significant reduction in the progression of joint structure changes compared with placebo as assessed by measuring radiologic joint space narrowing (structure-modifying effect). The two effects combined may suggest a disease-modifying effect that was postulated based on an observed decrease in the risk of undergoing total joint replacement in the follow up of patients receiving the product for at least 12 months in the pivotal trials. The safety of the drug was good in clinical trials and in the postmarketing surveillance. Crystalline glucosamine sulfate 1500 mg once daily is therefore recommended in the majority of clinical practice guidelines and was found to be cost effective in pharmacoeconomic analyses. Compared with other glucosamine formulations, salts, or dosage forms, the prescription product achieves higher plasma and synovial fluid concentrations that are above the threshold for a pharmacologically relevant effect, and may therefore justify its distinct therapeutic characteristics.
Three-Dimensional Sonography, Tomographic Sonography Imaging, and the OmniView Algorithm
Authors: Tonni Gabriele , Rosignoli Lucia , Centini Giovanni , Lituania Mario , Doneda Chiara
Published: March 2012

The prenatal diagnosis of congenital dacryocystocele has been reported using 2D sonographic imaging, but there are very few reports of the use of 3D sonography for this diagnosis. Two cases are presented in which 3D and Doppler sonography was helpful in determining the prenatal diagnosis. The embryologic basis of this obstruction of the nasolacrimal duct is discussed along with techniques for the prenatal diagnosis, including the potential value of 3D sonography in limiting the necessity of other prenatal testing. The importance of establishing the differential diagnosis is also discussed, as there is the possibility of the dacryocystocele being secondary to a sinonasal tumor.
Structure and mineralogy of layer silicates
Authors: Brigatti Maria Franca , Malferrari Daniele , Laurora Angela , Elmi Chiara
Published: March 2012

Because of their many novel and advanced applications, there is increasing interest in layer silicates from the scientific and technical communities. Appropriate application of these minerals requires deep understanding of their properties and of the processes where they are involved. This chapter, by providing fundamental definitions and crystal structural and chemical data pertaining to layer silicates, aims to introduce this field to new researchers and technicians, by describing the fundamental features leading to different behaviours of layer silicates in different natural or technical processes. The subject addressed is vast and so the reader is referred in some cases to work already published. The focus here is on layer silicates for which detailed crystal structures are given in the literature and which are likely to be used in an applied way in the future. Layer-silicate minerals fulfilling these requirements are: (1) kaolin-serpentine group(e.g. kaolinite, dickite, nacrite, halloysite, hisingerite, odinite, lizardite, berthierine, amesite, cronstedtite, nepouite, kellyite, fraipontite, brindleyite, guidottiite, bementite, greenalite, caryopilite; minerals of the pyrosmalite series); (2) talc and pyrophyllite groups (e.g. pyrophyllite, ferripyrophyllite, willemseite); (3) mica group (i.e. some recent advances in crystal chemistry and structure of dioctahedral and trioctahedral micas); (4) smectite group (e.g. montmorillonite, saponite, hectorite, sauconite, stevensite, swinefordite); (5) vermiculite group; (6) chlorite group (e.g. trioctahedral chlorite such as clinochlore, di,trioctahedral and dioctahedral chlorites such as cookeite and sudoite); (7) some 2:1 layer silicates involving a discontinuous octahedral sheet and a modulated tetrahedral sheet such as kalifersite, palygorskite and sepiolite; and (8) imogolite and allophane.
An Overview of Order/Disorder in Hydrous Phyllosilicates
Authors: Guggenheim Stephen
Published: March 2012

The purpose of the chapter is to provide a condensed introduction for later chapters. Major features of atomic order and disorder in hydrous phyllosilicates are presented. Emphasisis on layer charge and the effects of cation distributions, layer stacking (polytypism), interstratified systems, modulated phyllosilicates and non-planar structures. Idealized phyllosilicate models are presented along with adjustments that structures require to compensate for lateral misfit of the semi-rigid component tetrahedral and octahedral sheets. Standard polytypes and interstratified structures are described along with the X-ray diffraction effects of both. Details of modulated systems and polysome relationships are given. In addition, the effects of the phyllosilicate interface with aqueous fluids and biomolecules are discussed.
The concept of layer charge of smectites and its implications for
important smectite-water properties
Authors: Christidis George E.
Published: March 2012

Layer charge is an important intrinsic property of smectites which stems from substitutions in the octahedral and/or tetrahedral sheet or from vacancies in the octahedral sheet. The layer charge is balanced by the interlayer cations which are exchangeable. There are three methods for determining layer charge: the structural formula method (SFM); the alkylammonium method (AMM); and the potassium-saturation method (KSM) which has been calibrated with the SFM. The layer charge affects important physical water-rock properties of smectites. Smectites with small layer charge have smaller cation exchange capacities than their high-charge counterparts. In contrast, during crystalline swelling, the activity of water at which the transition in hydration and dehydration occurs, increases with increasing layer charge of the smectites, suggesting that low-charge smectites have greater swelling capacity. In contrast, data on the influence of layer charge on double layer swelling are inconclusive, although in general low-charge smectites have greater swelling capacity than high-charge smectites. Similarly, the limited existing data suggest that, in general, low-charge smectites form more viscous suspensions than their high-charge counterparts. The influence of layer charge on the double layers welling and the viscosity is attributed to the formation of quasicrystals, i.e. small stacks of smectite layers, which may breakup by hydrodynamic forces under shearing. Layer charge is a property of the unit cell, i.e. it refers to the atomic not the macroscopic level and it does not reflect the charge of the smectite particles. Smectite-water properties can be better explained by the concept of fundamental particle charge, i.e. the electric charge of the single 10 Å thick smectite particles.
Advanced techniques to define intercalation processes
Authors: Mottana Annibale , Aldega Luca
Published: March 2012

Intercalation is the inclusion or reversible insertion of a guest chemical species (atom, ion, molecule) in a virtually unchanged host-crystal structure. Any type of layer-structured material may give rise to intercalated compounds, the guest species being artificially inserted or naturally included between the host sheets without loss of their planarity. Layer silicates, in particular, may be considered intercalated structures where interlayer guest species and complexes are inserted between the silicate layers. The most common guest species is H2O, which is generally present under natural conditions in intercalated layer silicates such as smectites, vermiculite and halloysite.

Past research focused attention on the swelling/shrinking behaviour of intercalated compounds with respect to H2O, and also on the non-stoichiometric, heterogeneous complexes formed from organic liquids such as ethylene glycol and glycerol. The unique combination of layer-silicate features (small crystal size, large surface area) and the small concentrations required to effect a change in the matrix, both coupled with the advanced characterization techniques available, have generated much interest. This interest extends to the special field of nanocomposites, and of graphene, which is also an intercalated layered structure. In general, any guest material inserted into an interlayer space causes a modification in the structure, with spacing-size changes in a particular crystallographic direction (d value). First, a brief introduction on conventional and synchroton-based X-ray techniques used to define crystal size and thickness is given. Then, the peak-broadening approach by conventional X-ray diffraction (XRD) techniques, such as the Scherrer method is presented. Further on, the crystallinity measurements and the Bertaut-Warren-Averbach (BWA) method used in the MudMaster program are described. A short summary is presented of the grazing-incidence diffraction (GIXRD) technique. Finally, additional and complementary information from X-ray absorption spectrometry (XAS), such as short-range order, and detailed local information on atomic positions by angle-resolved X-ray absorption near-edge stucture (AXANES), polarized extended X-ray absorption fine structure (P-EXAFS), and near-edge extended absorption fine structure (NEXAFS) spectroscopies are analysed and discussed. Examples of the applications of these methods to clay minerals, micas and graphene are given.
Engagement of NKp30 on Vδ1 T cells induces the production of CCL3, CCL4, and CCL5 and suppresses HIV-1 replication
Authors: Hudspeth Kelly , Fogli Manuela , Correia Daniel V. , Mikulak Joanna , Roberto Alessandra , Della Bella Silvia , Silva-Santos Bruno , Mavilio Domenico
Published: March 2012

Natural cytotoxicity receptors (NCRs) were originally identified as specific natural killer cell activating receptors that, on binding to their endogenous ligands, trigger the killing of tumor cell targets. We recently described the differentiation of a novel subset of NCR+ Vδ1 T cells characterized by a remarkably high cytolytic potential against cancer cells. Here we demonstrate that the engagement of NKp30, one of the NCRs expressed de novo on Vδ1 T cells after stimulation, triggers the production of high levels of CCL3/MIP-1α, CCL4/ MIP-1β, and CCL5/RANTES but not of CXCL12/SDF-1. In turn, this NKp30-induced secretion of cc-chemokines is able to significantly suppress the replication of a CCR5 tropic strain of HIV-1 in CD4+/CCR5+ infected PM1 cell lines. This experimental evidence disclosing an unanticipated antiviral function of NCR+ Vδ1 T cells opens new avenues for understanding the pathogenic role and for manipulating the function of γδ T cells in HIV-1 infection.
Digestive vacuole of Plasmodium falciparum released during erythrocyte rupture dually activates complement and coagulation
Authors: Dasari Prasad , Heber Sophia D. , Beisele Maike , Torzewski Michael , Reifenberg Kurt , Orning Carolin , Fries Anja , Zapf Anna-Lena , Baumeister Stefan , Lingelbach Klaus , Udomsangpetch Rachanee , Bhakdi Sebastian Chakrit , Reiss Karina , Bhakdi Sucharit
Published: March 2012

Severe Plasmodium falciparum malaria evolves through the interplay among capillary sequestration of parasitized erythrocytes, deregulated inflammatory responses, and hemostasis dysfunction. After rupture, each parasitized erythrocyte releases not only infective merozoites, but also the digestive vacuole (DV), a membrane-bounded organelle containing the malaria pigment hemozoin. In the present study, we report that the intact organelle, but not isolated hemozoin, dually activates the alternative complement and the intrinsic clotting pathway. Procoagulant activity is destroyed by phospholipase C treatment, indicating a critical role of phospholipid head groups exposed at the DV surface. Intravenous injection of DVs caused alternative pathway complement consumption and provoked apathy and reduced nociceptive responses in rats. Ultrasonication destroyed complement-activating and procoagulant properties in vitro and rendered the DVs biologically inactive in vivo. Low-molecular-weight dextran sulfate blocked activation of both complement and coagulation and protected animals from the harmful effects of DV infusion. We surmise that in chronic malaria, complement activation by and opsonization of the DV may serve a useful function in directing hemozoin to phagocytic cells for safe disposal. However, when the waste disposal system of the host is overburdened, DVs may transform into a trigger of pathology and therefore represent a potential therapeutic target in severe malaria.
Poly (ADP-ribose) polymerase plays an important role in intermittent hypoxia-induced cell death in rat cerebellar granule cells
Authors: Chiu Sheng-Chun , Huang Sung-Ying , Tsai Yu-Chieh , Chen Shee-Ping , Pang Cheng-Yoong , Lien Chih-Feng , Lin Yu-Jou , Yang Kun-Ta
Published: March 2012

Background

Episodic cessation of airflow during sleep in patients with sleep apnea syndrome results in intermittent hypoxia (IH). Our aim was to investigate the effects of IH on cerebellar granule cells and to identify the mechanism of IH-induced cell death.

Methods

Cerebellar granule cells were freshly prepared from neonatal Sprague-Dawley rats. IH was created by culturing the cerebellar granule cells in the incubators with oscillating O2 concentration at 20% and 5% every 30 min for 1-4 days. The results of this study are based on image analysis using a confocal microscope and associated software. Cellular oxidative stress increased with increase in IH. In addition, the occurrence of cell death (apoptosis and necrosis) increased as the duration of IH increased, but decreased in the presence of an iron chelator (phenanthroline) or poly (ADP-ribose) polymerase (PARP) inhibitors [3-aminobenzamide (3-AB) and DPQ]. The fluorescence of caspase-3 remained the same regardless of the duration of IH, and Western blots did not detect activation of caspase-3. However, IH increased the ratio of apoptosis-inducing factor (AIF) translocation to the nucleus, while PARP inhibitors (3-AB) reduced this ratio.

Results

According to our findings, IH increased oxidative stress and subsequently leading to cell death. This effect was at least partially mediated by PARP activation, resulting in ATP depletion, calpain activation leading to AIF translocation to the nucleus.

Conclusions

We suggest that IH induces cell death in rat primary cerebellar granule cells by stimulating oxidative stress PARP-mediated calpain and AIF activation.
Comparative effectiveness research on patients with acute ischemic stroke using Markov decision processes
Authors: Wu Darong , Cai Yefeng , Cai Jianxiong , Liu Qiuli , Zhao Yuanqi , Cai Jingheng , Zhao Min , Huang Yonghui , Ye Liuer , Lu Yubo , Guo Xianping
Published: March 2012

Background

Several methodological issues with non-randomized comparative clinical studies have been raised, one of which is whether the methods used can adequately identify uncertainties that evolve dynamically with time in real-world systems. The objective of this study is to compare the effectiveness of different combinations of Traditional Chinese Medicine (TCM) treatments and combinations of TCM and Western medicine interventions in patients with acute ischemic stroke (AIS) by using Markov decision process (MDP) theory. MDP theory appears to be a promising new method for use in comparative effectiveness research.

Methods

The electronic health records (EHR) of patients with AIS hospitalized at the 2nd Affiliated Hospital of Guangzhou University of Chinese Medicine between May 2005 and July 2008 were collected. Each record was portioned into two "state-action-reward" stages divided by three time points: the first, third, and last day of hospital stay. We used the well-developed optimality technique in MDP theory with the finite horizon criterion to make the dynamic comparison of different treatment combinations.

Results

A total of 1504 records with a primary diagnosis of AIS were identified. Only states with more than 10 (including 10) patients' information were included, which gave 960 records to be enrolled in the MDP model. Optimal combinations were obtained for 30 types of patient condition.

Conclusion

MDP theory makes it possible to dynamically compare the effectiveness of different combinations of treatments. However, the optimal interventions obtained by the MDP theory here require further validation in clinical practice. Further exploratory studies with MDP theory in other areas in which complex interventions are common would be worthwhile.
Keeping participants on board: increasing uptake by automated respondent reminders in an Internet-based Chlamydia Screening in the Netherlands
Authors: Dokkum Nynke FB , Koekenbier Rik H , van den Broek Ingrid VF , van Bergen Jan EAM , Brouwers Elfi EHG , Fennema Johannes SA , Götz Hannelore M , Hoebe Christian JPA , Pars Lydia L , van Ravesteijn Sander M , Op de Coul Eline LM
Published: March 2012

Background

Effectiveness of Chlamydia screening programs is determined by an adequate level of participation and the capturing of high-risk groups. This study aimed to evaluate the contribution of automated reminders by letter, email and short message service (SMS) on package request and sample return in an Internet-based Chlamydia screening among people aged 16 to 29 years in the Netherlands.

Methods

Individuals not responding to the invitation letter received a reminder letter after 1 month. Email- and SMS-reminders were sent to persons who did not return their sample. It was examined to what extent reminders enhanced the response rate (% of package requests) and participation rate (% of sample return). Sociodemographic and behavioural correlates of providing a cell phone number and participation after the reminder(s) were studied by logistic regression models.

Results

Of all respondents (screening round 1: 52,628, round 2: 41,729), 99% provided an email address and 72% a cell phone number. Forty-two percent of all package requests were made after the reminder letter. The proportion of invitees returning a sample increased significantly from 10% to 14% after email/SMS reminders (round 2: from 7% to 10%). Determinants of providing a cell-phone number were younger age (OR in 25-29 year olds versus 16-19 year olds = 0.8, 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch = 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.1, 95%CI 1.0-1.2, Sub Sahara African: 1.5, 95%CI 1.3-1.8, non-Western other 1.1, 95%CI 1.1-1.2), lower educational level (OR in high educational level versus low level = 0.8, 95%CI 0.7-0.9), no condom use during the last contact with a casual partner (OR no condom use versus condom use 1.2, 95%CI 1.1-1.3), younger age at first sexual contact (OR 19 years or older versus younger than 16: 0.7, 95%CI 0.6-0.8). Determinants for requesting a test-package after the reminder letter were male gender (OR female versus male 0.9 95%CI 0.8-0.9), non-Dutch (OR in Surinam/Antillean versus Dutch 1.3, 95%CI 1.2-1.4, Turkish/Moroccan: 1.4, 95%CI 1.3-1.5, Sub Sahara African: 1.4, 95%CI 1.2-1.5, non-Western other: 1.2, 95%CI 1.1-1.2), having a long-term steady partnership (long-term versus short-term.1.2 95%CI 1.1-1.3). Email/SMS reminders seem to have resulted in more men and people aged 25-29 years returning a sample.

Conclusions

Nearly all respondents (99.5%) were reachable by modern communication media. Response and participation rates increased significantly after the reminders. The reminder letters also seemed to result in reaching more people at risk. Incorporation of automated reminders in Internet-based (Chlamydia) screening programs is strongly recommended.
B-cell activity in children with malaria
Authors: Korir Jackson C , Magambo Japhet K , Mwatha Joseph K , Waitumbi John N
Published: March 2012

Background

Recent studies implicate deficiency of red blood cell (RBC) complement regulatory proteins (CR1 and CD55) in the pathogenesis of malarial anaemia. This study explored the involvement of B cell CD21, which has an analogous role to RBC CR1.

Methods

In a case control study conducted in Kisumu District hospital, western Kenya, children with severe malaria anaemia (SMA) and those with uncomplicated malaria (UM) were assessed by flow cytometry for B cells (CD20+) numbers, expression levels of CD21 and deposition of C3dg and by ELISA for soluble CD21 (sCD21). Paired t tests were used to determine statistical significance at a = 0.05.

Results

Children with SMA had significantly higher lymphocyte count (9,627.7 ± 8786.1 SD vs. 5,507 ± 2436 SD,P= 0.04 in the UM group) and the computed geometric mean of mature B-cell numbers based on the absolute lymphocyte count was significantly higher for SMA group: 1,823 (1,126 to 2,982, 95% CI) and 826.6 (564 to 1,220, 95% CI)] for UM group (P= 0.003). SMA group also had a higher percentage of CD20+ B cells (26.8 ± 9.7SD vs 20.9 ± 9.01 SD in the UM) (P =0.03), indicating considerable polyclonal B-cell activation. The CD21 median flourescence intensity was lower in the SMA (246.4 ± 87.4 SD vs 369 ± 137.7 SD) (P <0.0001), probably due to complement mediated shaving of CD21 by fixed tissue macrophages. The CD20+ B cells of SMAs had higher levels of the complement split product C3dg (18.35 ± 10 SD vs 11.5 ± 6.8 S.D), (P= 0.0002), confirming possible role of complement in CD21 removal. Unexpectedly, the SMAs had lower levels of sCD21 (226.5 ± 131.5 SD vs 341.4 ± 137.3 SD in the UM) (P< 0.0001), indicating that the shaved CD21 is not released to peripheral circulation.

Conclusions

These results implicate B-cell in pathophysiology of severe malaria that involves increased B-cell proliferation, increased complement deposition and subsequent loss of membrane-bound CD21. The loss of CD21 is not by the classical enzmatic cleavage.
Biological activities of nitidine, a potential anti-malarial lead compound
Authors: Bouquet Jérome , Rivaud Marion , Chevalley Séverine , Deharo Eric , Jullian Valérie , Valentin Alexis
Published: March 2012

Background

Nitidine is thought to be the main active ingredient in several traditional anti-malarial remedies used in different parts of the world. The widespread use of these therapies stresses the importance of studying this molecule in the context of malaria control. However, little is known about its potential as an anti-plasmodial drug, as well as its mechanism of action.

Methods

In this study, the anti-malarial potential of nitidine was evaluated in vitro on CQ-sensitive and -resistant strains. The nitidine's selectivity index compared with cancerous and non-cancerous cell lines was then determined. In vivo assays were then performed, using the four-day Peter's test methodology. To gain information about nitidine's possible mode of action, its moment of action on the parasite cell cycle was studied, and its localization inside the parasite was determined using confocal microscopy. The in vitro abilities of nitidine to bind haem and to inhibit β-haematin formation were also demonstrated.

Results

Nitidine showed similar in vitro activity in CQ-sensitive and resistant strains, and also a satisfying selectivity index (> 10) when compared with a non-cancerous cells line. Its in vivo activity was moderate; however, no sign of acute toxicity was observed during treatment. Nitidine's moment of action on the parasite cycle showed that it could not interfere with DNA replication; this was consistent with the observation that nitidine did not localize in the nucleus, but rather in the cytoplasm of the parasite. Nitidine was able to form a 1-1 complex with haem in vitro and also inhibited β-haematin formation with the same potency as chloroquine.

Conclusion

Nitidine can be considered a potential anti-malarial lead compound. Its ability to complex haem and inhibit β-haematin formation suggests a mechanism of action similar to that of chloroquine. The anti-malarial activity of nitidine could therefore be improved by structural modification of this molecule to increase its penetration of the digestive vacuole in the parasite, where haemoglobin metabolization takes place.
Effect of cancer-associated mutations in the PlexinB1 gene
Authors: Zhou Chun , Wong Oscar Gee-Wan , Masters John R , Williamson Magali
Published: March 2012

Background

Semaphorins act as chemotactic cues for cell movement via their transmembrane receptors, plexins. Somatic missense mutations in the plexinB1 gene coupled with overexpression of the protein frequently occur in prostate tumours, indicating a role for plexinB1 in the pathogenesis of prostate cancer.

Results

Two specific mutations found in prostate cancer enhance RhoD binding and one other mutation results in loss of inhibition of Rac-dependent Pak1 phosphorylation and lamellipodia formation and in impairment of trafficking of plexinB1 to the membrane. None of the three characterised mutations affect PDZRhoGEF binding, RhoA activity, the interaction of plexinB1with the oncogenes ErbB2 or c-Met or ErbB2 phosphorylation. The mutations have the net effect of increasing cell motility by blocking plexinB1-mediated inhibition of Rac while enhancing the interaction with RhoD, an anti-migratory factor.

Conclusions

PlexinB1 mutations block plexinB1-mediated signalling pathways that inhibit cell motility.
Anti-inflammation effects of hydrogen saline in LPS activated macrophages and carrageenan induced paw oedema
Authors: Xu Zheng , Zhou Jiangrui , Cai Jianmei , Zhu Zhen , Sun Xuejun , Jiang Chunlei
Published: March 2012

Background

Oxidative stress is thought to play an important role in the pathogenesis of inflammation. Recent studies have found that hydrogen gas has the effect of eliminating free radicals. Whether hydrogen saline (more convenient to be used than hydrogen gas) has the anti-inflammation effect or not is still unknown.

Methods

Carrageenan-induced paw oedema and LPS-activated macrophages are studied in this article. Injection of carrageenan into the foot of a mouse elicited an acute inflammatory response characterized by increase of foot volume and infiltration of neutrophils. While tumor necrosis factorα(TNF-α) secreted by activated macrophages was determined by ELISA and real-time PCR.

Results

All parameters of inflammation (foot volume, infiltration of neutrophils, amount of TNF-α and the level of TNF-α's mRNA) were attenuated by the hydrogen saline treatment.

Conclusion

As a more convenient way than inhaling H2, hydrogen saline exhibits a protective effect against inflammation and it might provide a novel therapeutic approach for inflammatory diseases.