bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of spherical and platelet-like nanoparticles on physical and mechanical properties of polyethylene terephthalate
Authors: Farhoodi Mehdi , Mousavi Seyed Mohammad Ali , Sotudeh-Gharebagh Rahmat , Emam-Djomeh Zahra , Oromiehie Abdolrasul
Published: February 2013

The influence of spherical (titanium dioxide (TiO2)) and platelet-like (Closite20A) nanofillers on the physical properties of polyethylene terephthalate (PET) nanocomposites was investigated. PET nanocomposites were prepared by melt blending of PET and nanofillers. Differential scanning calorimetry showed that PET nanocomposites had higher crystallinity than the neat PET, possibly due to the nucleating role of the nanoparticles. It was observed that the influence of nanoclays on crystallization of PET is more considerable than TiO2 nanoparticles. For PET/TiO2 and PET/clay nanocomposites, the highest value of crystallinity observed at 3 wt% and 1 wt% loading level of TiO2 and Closite20Ananoparticles, respectively. Scanning electron microscopic micrographs showed that uniform distribution and good dispersion of TiO2 through PET matrix were achieved at 1 and 3 wt% loadings but at higher loadings up to 5 wt%, nanoparticles tend to accumulate. Transmission electron microscopy and wide angle X-ray diffraction showed that the dominant structure of PET nanocomposites containing 1 wt% nanoclays was exfoliation while at higher loading levels, the shift in peak to lower angles and subsequent increase in platelet spacing suggest intercalated structure. The addition of TiO2 nanoparticles caused noticeable enhancement of PET ductility, while the incorporation of nanoclays into PET matrix developed a fragile structure with lower ductility.
Thermal properties of carboxylated nitrile rubber/nylon-12 composites-filled lignocellulose materials
Authors: Mousa A , Heinrich G , Wagenknecht U
Published: February 2013

Organic hybrid composites based on carboxylated nitrile rubber and nylon-12 reinforced with mercerized and diisocyanated lignocellulose residue (LCR) was prepared. The influence of the LCR on the viscoelastic properties of these organic hybrids was investigated by dynamic mechanical analysis and thermal analysis (differential scanning calorimetry (DSC)). It is found that either the position of the damping peak was shifted to higher values or the intensity of the damping peak was significantly increased with LCR. These results could imply that the LCR enhanced the damping properties of the composites. The thermal stability of the composites was evaluated with the mean values obtained using thermogravimetrical analysis. The decomposition rate was investigated using differential thermal gravimetry. The crystallization behavior of the prepared composites was checked by DSC.
Simulation of active skeletal muscle tissue with a transversely isotropic viscohyperelastic continuum material model
Authors: Khodaei Hamid , Mostofizadeh Salar , Brolin Karin , Johansson Håkan , Östh Jonas
Published: February 2013

Human body models with biofidelic kinematics in vehicle pre-crash and crash simulations require a constitutive model of muscle tissue with both passive and active properties. Therefore, a transversely isotropic viscohyperelastic continuum material model with element-local fiber definition and activation capability is suggested for use with explicit finite element codes. Simulations of experiments with New Zealand rabbit’s tibialis anterior muscle at three different strain rates were performed. Three different active force–length relations were used, where a robust performance of the material model was observed. The results were compared with the experimental data and the simulation results from a previous study, where the muscle tissue was modeled with a combination of discrete and continuum elements. The proposed material model compared favorably, and integrating the active properties of the muscle into a continuum material model opens for applications with complex muscle geometries.
Biodiversity variability across elevations in the Carpathians: Parallel change with landscape openness and land use
Authors: Feurdean Angelica , Parr Catherine L , Tanţău Ioan , Fărcaş Sorina , Marinova Elena , Perşoiu Ioana
Published: February 2013

An understanding of contemporary and likely future biodiversity requires knowledge of how past human societies have shaped diversity patterns. Here, we use long-term pollen data sets extending from lowlands to subalpine environment in the Carpathian region (Romania) with the aim of exploring the relationship between landscape openness, anthropogenic disturbance, elevation and vegetation richness over the Holocene. We found that landscape openness represents a significant driver of pollen richness: The more open sites from mid (440–750 m) and high elevations (1550–1850 m) showed on average greater diversity than more forested upland sites (1050–1360 m). For the first time, our results show pollen richness patterns along elevation gradients that remain constant over the Holocene. Although significant only over the last 3000 cal. yr BP, these elevational patterns become accentuated with stronger evidence of anthropogenic impact. We also found a strong link between diversity change and major land use strategies of prehistoric societies, demonstrating the potential of pollen richness to be used as a tool to depict the ecological impact of human disturbance on diversity. Most distinct episodes of enhanced floristic richness are evident during the Roman Period (2000 cal. yr BP), and over the last 500 cal. yr BP. Recent anthropogenic activity negatively impacted diversity in mountainous areas mainly through plantations; the lack of sites in agriculture landscapes however limits our inference for this type of setting. The maintenance of habitat diversity is key to maintaining high levels of diversity. While there is temporal consistency in the diversity pattern in records from similar climate and vegetation settings, comparison of diversity from different vegetation assemblages and levels landscapes openness should be interpreted cautiously.
Comparing models for quantitative risk assessment: an application to the European Registry of foreign body injuries in children
Authors: Berchialla Paola , Scarinzi Cecilia , Snidero Silvia , Gregori Dario
Published: February 2013

Risk Assessment is the systematic study of decisions subject to uncertain consequences. An increasing interest has been focused on modeling techniques like Bayesian Networks since their capability of (1) combining in the probabilistic framework different type of evidence including both expert judgments and objective data; (2) overturning previous beliefs in the light of the new information being received and (3) making predictions even with incomplete data. In this work, we proposed a comparison among Bayesian Networks and other classical Quantitative Risk Assessment techniques such as Neural Networks, Classification Trees, Random Forests and Logistic Regression models. Hybrid approaches, combining both Classification Trees and Bayesian Networks, were also considered. Among Bayesian Networks, a clear distinction between purely data-driven approach and combination of expert knowledge with objective data is made. The aim of this paper consists in evaluating among this models which best can be applied, in the framework of Quantitative Risk Assessment, to assess the safety of children who are exposed to the risk of inhalation/insertion/aspiration of consumer products. The issue of preventing injuries in children is of paramount importance, in particular where product design is involved: quantifying the risk associated to product characteristics can be of great usefulness in addressing the product safety design regulation. Data of the European Registry of Foreign Bodies Injuries formed the starting evidence for risk assessment. Results showed that Bayesian Networks appeared to have both the ease of interpretability and accuracy in making prediction, even if simpler models like logistic regression still performed well.
Extended cognition in science communication
Authors: Ludwig David
Published: February 2013

The aim of this article is to propose a methodological externalism that takes knowledge about science to be partly constituted by the environment. My starting point is the debate about extended cognition in contemporary philosophy and cognitive science. Externalists claim that human cognition extends beyond the brain and can be partly constituted by external devices. First, I show that most studies of public knowledge about science are based on an internalist framework that excludes the environment we usually utilize to make sense of science and does not allow the possibility of extended knowledge. In a second step, I argue that science communication studies should adopt a methodological externalism and accept that knowledge about science can be partly realized by external information resources such as Wikipedia.
Aims and harvest of moral case deliberation
Authors: Weidema Froukje C , Molewijk Bert AC , Kamsteeg Frans , Widdershoven Guy AM
Published: February 2013

Deliberative ways of dealing with ethical issues in health care are expanding. Moral case deliberation is an example, providing group-wise, structured reflection on dilemmas from practice. Although moral case deliberation is well described in literature, aims and results of moral case deliberation sessions are unknown. This research shows (a) why managers introduce moral case deliberation and (b) what moral case deliberation participants experience as moral case deliberation results. A responsive evaluation was conducted, explicating moral case deliberation experiences by analysing aims (N = 78) and harvest (N = 255). A naturalistic data collection included interviews with managers and evaluation questionnaires of moral case deliberation participants (nurses). From the analysis, moral case deliberation appeals for cooperation, team bonding, critical attitude towards routines and nurses’ empowerment. Differences are that managers aim to foster identity of the nursing profession, whereas nurses emphasize learning processes and understanding perspectives. We conclude that moral case deliberation influences team cooperation that cannot be controlled with traditional management tools, but requires time and dialogue. Exchanging aims and harvest between manager and team could result in co-creating (moral) practice in which improvements for daily cooperation result from bringing together perspectives of managers and team members.
Modelling the friction contact in an inertia motor
Authors: Hunstig Matthias , Hemsel Tobias , Sextro Walter
Published: February 2013

Piezoelectric inertia motors, also known as stick–slip drives or (smooth) impact drives, use the inertia of a body to drive it by a friction contact in small steps, in the majority of motors composed of a stick phase and a slip phase between the friction partners. For optimizing inertia motors, it is important to understand the friction contact correctly and to measure its properties appropriately. This contribution presents experimental set-ups for measuring the contact force, friction force and relative displacement in an actual inertia motor with a dry friction contact and numerical simulations of the motor operation. The motor uses a pre-stressed multilayer actuator with a displacement in the range of 20 µm. It is shown that a previously postulated condition for the applicability of simple kinetic friction models is well fulfilled for the investigated motor. The friction contact in the motor is simulated using different kinetic friction models. The input for the friction models is the measured motion of the rod. The models qualitatively reproduce the measured motion but show quantitative deviations varying with frequency. These can be explained by vibrations of the driving rod that are experimentally investigated.
An improved electromechanical model and parameter identification technique for piezoelectric actuators
Authors: Islam Mohammad N , Seethaler Rudolf J
Published: February 2013

Piezoelectric actuators are often modeled as a lumped mass system in the mechanical domain and as a capacitive element in the electrical domain. Based on a real-time capacitance measurement, it is observed that the piezoelectric capacitance is a function of voltage. This leads to a modification of the traditional piezoelectric actuator model where the capacitance is usually considered constant. A voltage-dependent capacitance term is introduced in the constitutive equations in the electrical domain, and it is demonstrated that this term satisfies a power balance. Then, a novel parameter identification technique is proposed for the modified constitutive equations. The advantage of this identification technique lies in its simplicity that requires only a single experiment to identify all pertinent model parameters. In addition, the hysteresis voltage is conveniently extracted from the applied voltage for a large frequency range. In comparison to the traditional parameter identification procedure and electromechanical models, the proposed technique along with the modified model provides an improved fitting of the parameters. The new model and its identification technique can be applied to sensorless position control applications where exact models are the basis for robust control system designs.
Survey on broadband techniques for vibration energy harvesting
Authors: Twiefel Jens , Westermann Henrik
Published: February 2013

Various energy harvesting systems have been proposed in the last years. The use of ambient energy, such as vibration energy, has evoked great interests. Most vibration-based converters generate the maximum power only when the generator is excited at its resonance frequency. To overcome this limitation, researchers focus on strategies for increasing the working bandwidth of an energy harvester. Due to the amount of different approaches for broadband energy harvesting, we suggest a categorization. This review presents a classification of the current techniques. Every technique has its own benefits and drawbacks and is suitable for different applications. This review presents the categorization and describes each conversion technique. Typical research approaches are shown to get a better understanding of the energy harvesting techniques. The advantages and drawbacks are presented, and the suitability is shown for each category.
Adolescents’ Experience With Workplace Aggression
Authors: Smith Carolyn R. , Fisher Bonnie S. , Gillespie Gordon L. , Beery Theresa A. , Gates Donna M.
Published: February 2013

Aggression exposure is a critical health issue facing adolescents in the United States. Exposure occurs in various settings including home, school, and the community. An emerging context for aggression exposure is in the workplace. Thirty adolescent employees age 16–18 participated in a qualitative study exploring proposed responses to future workplace aggression. Semistructured interviews were used to gather participants’ proposed responses to a series of hypothetical aggressive incidents in the workplace. Conventional content analysis identified patterns and themes among the participants’ responses. Results indicated adolescent employees’ proposed responses to workplace aggression are similar to other forms of aggression such as peer-bullying and teen dating violence. Education and training are needed within the school setting to promote appropriate responses to various forms of aggression encountered by adolescents. Implications for school health professionals’ involvement in addressing responses to such aggression and further research opportunities are explored.
Low-Grade, Metastasizing Splenic Littoral Cell Angiosarcoma Presenting With Hepatic Cirrhosis and Splenic Artery Aneurysm
Authors: Larsen Brandon T. , Bishop Maria C. , Hunter Glenn C. , Renner Stephen W.
Published: February 2013

The behavior of littoral cell neoplasms ranges from benign (littoral cell angioma, LCA) to highly malignant (angiosarcoma). Two unusual cases of low-grade metastatic littoral cell angiosarcoma (LCAS) have been reported with late recurrence and bulky metastases. We present the third case of this rare neoplasm in a 38-year-old man with cirrhosis and a large splenic artery aneurysm, without extrasplenic masses. The spleen showed nodules resembling LCA, immunoreactive for CD31, factor VIII, CD68, and CD163 but not CD8 or CD34. Also present were solid areas of immunophenotypically identical bland spindle cells, although lighter CD31 immunostaining distinguished them from LCA-like angiomatous channels. Similar cells diffusely infiltrated the cirrhotic liver. After splenectomy, pancytopenia resolved, and he is asymptomatic 19 months later. Low-grade LCAS is a previously unreported cause of cirrhosis and may metastasize without forming masses. In cases of LCA, CD31 immunohistochemistry may facilitate detection of LCAS and indicate metastatic potential.
Weak fault feature extraction of rolling bearing based on minimum entropy de-convolution and sparse decomposition
Authors: Wang Hongchao , Chen Jin , Dong Guangming
Published: February 2013

The rolling bearing fault signal under strong background noise is very weak because of environmental noise impaction and the attenuation of signal. The feature extraction of rolling bearings’ weak fault is very important in avoiding serious disaster, but it is also very difficult. Sparse decomposition has been used in the fault feature extraction of rolling bearings. But its performance is very poor when the background noise is very strong. This text combines the minimum entropy de-convolution (MED) and sparse decomposition to extract the feature of a rolling bearing’s weak fault. Firstly, the rolling bearing weak fault signal with strong background noise is de-noised using the MED method, and subsequently the de-noised signal is handled by sparse decomposition. Finally, the fault feature extraction method-envelope demodulation is carried on the last given signal and better results are obtained. In conclusion, through simulation and experiment the effectiveness and the feasibility of the proposed method are verified.
The best laid plans? Women’s choices, expectations and experiences in childbirth
Authors: Malacrida Claudia , Boulton Tiffany
Published: February 2013

The past decades have seen a drastic increase in the medicalization of childbirth, evidenced by increasing Caesarean section rates in many Western countries. In a rare moment of congruence, alternative health-care providers, feminist advocates for women’s health and, most recently, mainstream medical service providers have all expressed serious concerns about the rise in Caesarean section rates and women’s roles in medicalization. These concerns stem from divergent philosophical positions as well as differing assumptions about the causes for increasing medicalization. Drawing on this debate, and using a feminist and governmentality framing of the problem, we interviewed 22 women who have recently had children about their birthing choices, their expectations and their birth experiences. The women’s narratives revealed a disjuncture between their expectations of choosing, planning and achieving as natural a birth as possible, and their lived experiences of births that did not typically go to plan. They also reveal the disciplining qualities of both natural and medical discourses about birth and choice. Furthermore, their narratives counter assumptions that women, as ideal patient consumers, are driving medicalization.
Newcomer Adjustment Among Recent College Graduates
Authors: Klemme Larson Rachel E. , Bell Alexandra A.
Published: February 2013

Newcomer adjustment, the process an individual goes through within the first year at a new organization, can be a challenging transition for traditionally aged recent college graduates. Unsuccessful adjustment can have profound negative consequences for young adults, organizations, and undergraduate institutions. Gaps exist in the human resource development (HRD) and undergraduate education literature leaving practitioners in both fields unsure of how to address this problem. Research regarding individual psychological capital (PsyCap) and proactive behaviors offer new perspectives that enhance understanding of newcomer adjustment and guide practice. In this integrative literature review we present a synthesis of research demonstrating positive interrelationships among PsyCap, proactive behaviors, and newcomer adjustment outcomes such as job performance, job satisfaction, and organizational commitment. Based on the outcomes we offer a model of newcomer adjustment that can guide researchers and practitioners in HRD and undergraduate education in working together to promote successful newcomer adjustment among recent college graduates.
Vascular Endostapling Systems for Vascular Endografts (T)EVAR—Systematic Review—Current State
Authors: Bail Dorothee H. L. , Walker Tobias , Giehl Johannes
Published: February 2013

Purpose:

Recently, vascular endostapling systems were developed to achieve better sealing at the proximal neck of the aneurysm and to prevent endograft migration. The purpose of this study was to provide a systematic review about the current state and possible options of vascular endostapling systems.

Results:

No randomized controlled trials were published. The results showed that the use of an endostaple system considerably reduced the rates of endoleaks type 1a and endograft migration. Regarding the use of endostaples in different types of endografts, only a few results were available.

Conclusion:

The results are not conclusive. With endostaple systems, patients with difficult anatomic features and high risk can potentially be treated. These systems might reduce the high reintervention rates after endovascular aneurysm repair. Controlled randomized trials with larger number of patients are warranted with endostapling use in primary endograft implantation and for use in reintervention for late endoleaks or endograft migrations.
Content Validity Using a Mixed Methods Approach
Authors: Newman Isadore , Lim Janine , Pineda Fernanda
Published: February 2013

There is paucity of detailed information in the literature on how to develop procedures for estimating content validity to increase trustworthiness of assessment instruments. The authors present three unique examples, interpretation, and application of Tables of Specifications (ToS) for generating these estimates. The development and logic of the ToS requires presenting evidence that has transparency and creates trustworthiness in the validity estimates by maintaining an audit trail and using of triangulation, expert debriefing, and peer review. The argument presented is that content validity requires a mixed methods approach since data are developed through qualitative and quantitative methods that inform each other. This process is iterative and provides feedback on the effectiveness of the ToS through a process of determining consensus.
Wnt signaling in bone formation and its therapeutic potential for bone diseases
Authors: Kim Jeong Hwan , Liu Xing , Wang Jinhua , Chen Xiang , Zhang Hongyu , Kim Stephanie H. , Cui Jing , Li Ruidong , Zhang Wenwen , Kong Yuhan , Zhang Jiye , Shui Wei , Lamplot Joseph , Rogers Mary Rose , Zhao Chen , Wang Ning , Rajan Prashant , Tomal Justin , Statz Joseph , Wu Ningning , Luu Hue H. , Haydon Rex C. , He Tong-Chuan
Published: February 2013

The Wnt signaling pathway plays an important role not only in embryonic development but also in the maintenance and differentiation of the stem cells in adulthood. In particular, Wnt signaling has been shown as an important regulatory pathway in the osteogenic differentiation of mesenchymal stem cells. Induction of the Wnt signaling pathway promotes bone formation while inactivation of the pathway leads to osteopenic states. Our current understanding of Wnt signaling in osteogenesis elucidates the molecular mechanisms of classic osteogenic pathologies. Activating and inactivating aberrations of the canonical Wnt signaling pathway in osteogenesis results in sclerosteosis and osteoporosis respectively. Recent studies have sought to target the Wnt signaling pathway to treat osteogenic disorders. Potential therapeutic approaches attempt to stimulate the Wnt signaling pathway by upregulating the intracellular mediators of the Wnt signaling cascade and inhibiting the endogenous antagonists of the pathway. Antibodies against endogenous antagonists, such as sclerostin and dickkopf-1, have demonstrated promising results in promoting bone formation and fracture healing. Lithium, an inhibitor of glycogen synthase kinase 3β, has also been reported to stimulate osteogenesis by stabilizing β catenin. Although manipulating the Wnt signaling pathway has abundant therapeutic potential, it requires cautious approach due to risks of tumorigenesis. The present review discusses the role of the Wnt signaling pathway in osteogenesis and examines its targeted therapeutic potential.
An Epidemiologic Analysis of Low Back Pain in Primary Care
Authors: Bener Abdulbari , Dafeeah Elnour E. , Alnaqbi Khalid , Falah Omar , Aljuhaisi Taha , Sadeeq Alhassan , Khan Shehryar , Schlogl Josia
Published: February 2013

Background: Low back pain is one of the most common conditions for which patients seek medical care. Aim: The aim of the study was to study the epidemiology of low back pain in primary care setting with emphasis on frequency, sociodemographic factors, and impact of low back pain on lifestyle habits. Subjects and Methods: This is a cross-sectional study. A representative sample of 2742 patients was approached and 2180 subjects agreed to participate in this study (79.5%). The survey was conducted among primary health care visitors during the period from March to October 2012. The questionnaire collected the sociodemographic characteristics, lifestyle habits, and type of treatment taken for relief from recruited subjects. Results: Of the subjects studied, 52.9% were males and 47.1% were females. The prevalence of low back pain in the study sample was 59.2%. Low back pain was more prevalent among women (67.7%) than among men (51.6%). The proportion of low back pain was highest in the age-group 45 to 55 years in both the genders (37.6% and 36.4%, respectively). Nearly half of the men (45.7%) and women (45.2%) with low back pain were overweight with a significant difference ( P < .001). More than half of the women with low back pain were housewives (50.4%), whereas most of the men had clerical jobs (36.8%). There was a significant difference observed between men and women in terms of nationality ( P < .001), body mass index ( P < .001), and occupation ( P < .001). Prolonged standing (41.2% vs 29.5%; P < .001) and use of sponge mattress (50.9% vs 45.8%; P .041) was significantly higher among male patients with low back pain compared with females. Coughing/sneezing/straining (9.7% vs 5.9%; P = .01) were more frequent triggering factors in male patients with low back pain as compared with females. Conclusion: The study findings revealed that the prevalence of low back pain was higher among women than among men. Low back pain was observed more frequently among older people and among those who were overweight.
Analysis of the storage and secretion of von Willebrand factor in blood outgrowth endothelial cells derived from patients with von Willebrand disease
Authors: Wang Jiong-Wei , Bouwens Eveline A. M. , Pintao Maria Carolina , Voorberg Jan , Safdar Huma , Valentijn Karine M. , de Boer Hetty C. , Mertens Koen , Reitsma Pieter H. , Eikenboom Jeroen
Published: February 2013

Key Points

Isolation of BOECs from multiple patients with VWD is feasible, and the study of BOECs helps explain the pathogenic complexity of VWD. Abnormalities in WPB biogenesis and exocytosis and defects in VWF string formation correlate with the phenotypic features of patients with VWD.
Attenuation of AML1-ETO cellular dysregulation correlates with increased leukemogenic potential
Authors: DeKelver Russell C. , Yan Ming , Ahn Eun-Young , Shia Wei-Jong , Speck Nancy A. , Zhang Dong-Er
Published: February 2013

Key Points

AML1-ETO-W692A loses interaction between NHR4 and N-CoR, decreases AML1-ETO cellular dysregulation, and promotes leukemia development in mice.
The role of 3-ketosteroid 1(2)-dehydrogenase in the pathogenicity of Mycobacterium tuberculosis
Authors: Brzezinska Marta , Szulc Izabela , Brzostek Anna , Klink Magdalena , Kielbik Michal , Sulowska Zofia , Pawelczyk Jakub , Dziadek Jaroslaw
Published: February 2013

Background

A growing body of evidence suggests that Mycobacterium tuberculosis (Mtb) uses the host’s cholesterol as a source of carbon and energy during infection. Strains defective in cholesterol transport or degradation exhibit attenuated growth in activated macrophages and diminished infectivity in animal models. The aim of this study was to evaluate intracellular replication of a cholesterol degradation-deficient Mtb mutant in human macrophages (MØ) in vitro and assess the functional responses of Mtb mutant-infected MØ.

Results

A mutant Mtb H37Rv strain containing an inactivated kstD gene (∆kstD), which encodes 3-ketosteroid 1(2)-dehydrogenase (KstD), was previously prepared using the homologous recombination-based gene-replacement technique. A control strain carrying the kstD gene complemented with an intact kstD was also previously constructed. In this study, human resting MØ were obtained after overnight differentiation of the human monocyte-macrophage cell line THP-1. Resting MØ were further activated with interferon-γ (IFN-γ). The ability of the kstD-defective Mtb mutant strain to replicate intracellularly in human MØ was evaluated using a colony-forming assay. Nitric oxide (NO) and reactive oxygen species (ROS) production by MØ infected with wild-type or ∆kstD strains was detected using Griess reagent and chemiluminescence methods, respectively. The production of tumor necrosis factor-α and interleukin-10 by MØ after infection with wild-type or mutant Mtb was examined using enzyme-linked immunosorbent assays.

We found that replication of mutant Mtb was attenuated in resting MØ compared to the wild-type or complemented strains. Moreover, the mutant was unable to inhibit the NO and ROS production induced through Toll-like receptor 2 (TLR2) signaling in infected resting MØ. In contrast, mutant and wild-type Mtb behaved similarly in MØ activated with IFN-γ before and during infection.

Conclusions

The Mtb mutant ∆kstD strain, which is unable to use cholesterol as a source of carbon and energy, has a limited ability to multiply in resting MØ following infection, reflecting a failure of the ∆kstD strain to inhibit the TLR2-dependent bactericidal activity of resting MØ.
A serine/threonine phosphatase encoded by MG_207 of Mycoplasma genitalium is critical for its virulence
Authors: Martinez Mario A , Das Kishore , Saikolappan Sankaralingam , Materon Luis A , Dhandayuthapani Subramanian
Published: February 2013

Background

Bacterial signal transduction systems like two component system (TCS) and Serine/Threonine kinase (STK) and Serine/Threonine phosphatase (STP) play important roles in the virulence and pathogenesis of bacterial pathogens. Mycoplasma genitalium, a mollicute that causes the urogenital diseases urethritis and cervicitis in men and women, respectively, is a pathogen which lacks TCS but possesses STK/STP. In this study, we investigated the biochemical and virulence properties of an STP protein encoded by the gene MG_207 of this species.

Results

We overexpressed MG207 in Escherichia coli overexpression system as a recombinant His10MG207 protein and purified it with affinity chromatography. This recombinant protein readily hydrolyzed the substrate p-nitrophenyl phosphate (pNPP) in a dose-dependent manner. Additional studies using synthetic peptides as substrates revealed that the recombinant protein was able to hydrolyze the threonine phosphate. Further, a transposon insertion mutant strain of M. genitalium (TIM207) that lacks the protein MG207 showed differentially phosphorylated proteins when compared to the wild type G37 strain. Mass spectrometry revealed that some of the key proteins differentially phosphorylated in TIM207 strain were putative cytoskeletal protein encoded by the gene MG_328 and pyruvate dehydrogenase E1 α chain encoded by the gene MG_274. In addition, TIM207 was noticed to be less cytotoxic to HeLa cells and this correlated with the production of less hydrogen peroxide by this strain. This strain was also less efficient in inducing the differentiation of THP-1 cell line as compared to wild type M. genitalium.

Conclusions

The results of the study suggest that MG207 is an important signaling protein of M. genitalium and its presence may be crucial for the virulence of this species.
Dealing with missing data in the Center for Epidemiologic Studies Depression self-report scale: a study based on the French E3N cohort
Authors: Resseguier Noémie , Verdoux Hélène , Giorgi Roch , Clavel-Chapelon Françoise , Paoletti Xavier
Published: February 2013

Background

The Center for Epidemiologic Studies - Depression scale (CES-D) is a validated tool commonly used to screen depressive symptoms. As with any self-administered questionnaire, missing data are frequently observed and can strongly bias any inference. The objective of this study was to investigate the best approach for handling missing data in the CES-D scale.

Methods

Among the 71,412 women from the French E3N prospective cohort (Etude Epidémiologique auprès des femmes de la Mutuelle Générale de l’Education Nationale) who returned the questionnaire comprising the CES-D scale in 2005, 45% had missing values in the scale. The reasons for failure to complete certain items were investigated by semi-directive interviews on a random sample of 204 participants. The prevalence of high depressive symptoms (score ≥16, hDS) was estimated after applying various methods for ignorable missing data including multiple imputation using imputation models with CES-D items with or without covariates. The accuracy of imputation models was investigated. Various scenarios of nonignorable missing data mechanisms were investigated by a sensitivity analysis based on the mixture modelling approach.

Results

The interviews showed that participants were not reluctant to answer the CES-D scale. Possible reasons for nonresponse were identified. The prevalence of hDS among complete responders was 26.1%. After multiple imputation, the prevalence was 28.6%, 29.8% and 31.7% for women presenting up to 4, 10 and 20 missing values, respectively. The estimates were robust to the various imputation models investigated and to the scenarios of nonignorable missing data.

Conclusions

The CES-D scale can easily be used in large cohorts even in the presence of missing data. Based on the results from both a qualitative study and a sensitivity analysis under various scenarios of missing data mechanism in a population of women, missing data mechanism does not appear to be nonignorable and estimates are robust to departures from ignorability. Multiple imputation is recommended to reliably handle missing data in the CES-D scale.
On the complexity-performance trade-off in soft-decision decoding for unequal error protection block codes
Authors: de Albuquerque Rebecca C , Cunha Daniel C , Pimentel Cecilio
Published: February 2013

Unequal error protection (UEP) codes provide a selective level of protection for different blocks of the information message. The effectiveness of two sub-optimum soft-decision decoding algorithms, namely generalized Chase-2 and weighted erasure decoding, is evaluated in this study for each protection class of UEP block codes. The performances of both algorithms are compared to that of the maximum likelihood algorithm in order to evaluate the performance loss of each protection class provided by less complex algorithms as well as their complexities are evaluated according to the number of arithmetic operations performed at each decoding step. Finally, numerical results and examples are provided which indicate that a trade-off between performance and complexity for each protection class is obtained. The results of this study can be used to select appropriate UEP coding and decoding schemes in applications that demand low energy consumption.
IMGT/Collier-de-Perles: a two-dimensional visualization tool for amino acid domain sequences
Authors: Vlachakis Dimitrios , Feidakis Christos , Megalooikonomou Vasileios , Kossida Sophia
Published: February 2013

IMGT/Collier-de-Perles is a tool that allows the user to analyze and draw two-dimensional graphical representations (or IMGT Collier de Perles) of protein domains (e.g., hydropathy plots). The IMGT/Collier-de-Perles specializes in the area of immunoglobulins (IG) or antibodies, T cell receptors (TR) and major histocompatibility (MH) of human and other vertebrate species as well as other proteins of the immunoglobulin superfamily (IgSF) and of the major histocompatibility superfamily (MhSF) and related proteins of the immune system of vertebrates and invertebrates.
Quantitative Measurements of Anaerobic Digestion Process Parameters Using near Infrared Spectroscopy and Local Calibration Models
Authors: Dahlbacka John , Lillhonga Tom
Published: February 2013

The performance of local calibration models for quantitative measurements of ammonium and acetate on samples from an anaerobic digestion process was examined. The local calibration methods used were locally weighted regression (LWR) and multi-layer partial least squares (ML-PLS) regression. The results of these two methods were compared to each other and to the results from the global partial least squares (PLS) model regression as well. For ammonium, both the local methods performed excellently in comparison with global PLS models. However, the results from the 150 LWR models regressed for ammonium also showed that the accuracy can be highly dependent on the different combination alternatives for model parameter settings and pre-processing alternatives. For this reason, a number of distance measures were evaluated as local subset selection methods in ML-PLS. The benefits of an optimised layer structure and the iterative approach in ML-PLS were also evaluated for ammonium. This showed that some benefits can be obtained by optimising the layer structure, at least in the sense that the number of layers can be reduced, and that there can be a significant advantage in using an iterative approach in the selection of the local subset of calibration data. The local calibration methods were also evaluated for acetate but, in this case, the benefits compared to global PLS calibration models were fairly insignificant with ML-PLS and none at all with LWR.
Short-Wave near Infrared Spectrometry of Back Scattering and Transmission of Light by Milk for Multi-Component Analysis
Authors: Kalinin Andrey V. , Krasheninnikov Viktor N. , Krivtsun Vladimir M.
Published: February 2013

Quality and authenticity of milk are usually defined by the content and composition of fat, proteins, total solids, somatic cells and other established indicators. Along with traditional reference methods for quantitative analysis, the use of near infrared (NIR) spectrometers and multivariate modelling is becoming more widely utilised. It would be useful to apply a spectrometer with a linear silicon CCD array as a rapid, portable and rather cheap supervising device. However, milk is a multiphase disperse system which includes a rough disperse phase of somatic cells and fatty globules, a thin phase of casein and whey proteins particles and the molecular solutions of lactose, salts, vitamins etc. in water. The scattering of incident light by particles of milk affect the signal of an NIR spectrometer significantly. The calibration of a spectrometer can be improved by considering the distinction between scattering by fatty globules and casein micelles. For this purpose, it is attractive to use the anisotropy of scattering by rough particles, in particular, by fatty globules. The comparative results for calibration models constructed with transmission and back scattering spectra of milk are presented in this paper. The spectra were acquired with a new two-channel short wave NIR spectrometer. Restored drinking milk has been modelled with a set of calibration samples, since the difference in the optical properties due to the globules and the micelles is significant and also because the reliable quality control of drinking milk using a simple spectrometer is a relevant practical problem. PLS models were constructed for the prediction of fat and protein and also of the fat-free total solids which serve as an indicator of authenticity for drinking milk. The results obtained demonstrate that a large reductions in errors is possible. The SEP value of not more than 0.08% wt was achieved when predicting the fat content of milk using a calibration based on the difference spectra of transmission and backscattering compared with a SEP of 0.21% wt for the model using transmission spectra only. For protein determination, the SEP was reduced from 0.25% wt to 0.12% wt if the calibration was based on the spectra of backscattering rather than on transmission.
Drahtlose Sensorsysteme für die zustandsorientierte Instandhaltung und Logistik
Authors: Thomasius Rolf , Guttowski Stephan , Brockmann Carsten , Benecke Stephan , Kravcenko Eduard , Nachsel Roman , Niedermayer Michael
Published: February 2013

Die Überwachung des Maschinenzustands ist die zwingende Voraussetzung für eine zustandsorientierte Instandhaltung. Hierzu sollen energieautarke Sensorsysteme nach dem Motto “Mount and forget” völlig wartungsfrei arbeiten und müssen zudem hohen Lebensdaueranforderungen gerecht werden. Batteriebasierte Lösungen scheiden dabei in der Regel aus. Sie werden ersetzt durch Systeme zur Versorgung mit Umgebungsenergie. Dieser Beitrag stellt Projekte und realisierte energieautarke Sensorsysteme vor aus den Bereichen zustandsbasierte Instandhaltung und Logistik, bespricht deren mögliche Energiequellen sowie Ultra-Low-Power Systemlösungen.
Age-associated changes in hypothalamic–pituitary–testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study
Authors: Camacho E M , Huhtaniemi I T , O'Neill T W , Finn J D , Pye S R , Lee D M , Tajar A , Bartfai G , Boonen S , Casanueva F F , Forti G , Giwercman A , Han T S , Kula K , Keevil B , Lean M E , Pendleton N , Punab M , Vanderschueren D , Wu F C W , _ _
Published: February 2013

Objective

Health and lifestyle factors are associated with variations in serum testosterone levels in ageing men. However, it remains unclear how age-related changes in testosterone may be attenuated by lifestyle modifications. The objective was to investigate the longitudinal relationships between changes in health and lifestyle factors with changes in hormones of the reproductive endocrine axis in ageing men.

Design

A longitudinal survey of 2736 community-dwelling men aged 40–79 years at baseline recruited from eight centres across Europe. Follow-up assessment occurred mean (±s.d.) 4.4±0.3 years later.

Results

Paired testosterone results were available for 2395 men. Mean (±s.d.) annualised hormone changes were as follows: testosterone −0.1±0.95 nmol/l; free testosterone (FT) −3.83±16.8 pmol/l; sex hormone-binding globulin (SHBG) 0.56±2.5 nmol/l and LH 0.08±0.57 U/l. Weight loss was associated with a proportional increase, and weight gain a proportional decrease, in testosterone and SHBG. FT showed a curvilinear relationship to weight change; only those who gained or lost ≥15% of weight showed a significant change (in the same direction as testosterone). Smoking cessation was associated with a greater decline in testosterone than being a non-smoker, which was unrelated to weight change. Changes in number of comorbid conditions or physical activity were not associated with significant alterations in hypothalamic–pituitary–testicular (HPT) axis function.

Conclusions

Body weight and lifestyle factors influence HPT axis function in ageing. Weight loss was associated with a rise, and weight gain a fall, in testosterone, FT and SHBG. Weight management appears to be important in maintaining circulating testosterone in ageing men, and obesity-associated changes in HPT axis hormones are reversible following weight reduction.
Effect of vascular endothelial growth factor receptor 2 antagonism on adiposity in obese mice
Authors: Lijnen H Roger , Scroyen Ilse
Published: February 2013

Development and maintenance of fat depots require angiogenesis, in which vascular endothelial growth factor (VEGF) and its receptors play a crucial role. We have evaluated the effect of blocking VEGF receptor 2 (VEGF-R2) with a MAB (DC101) on adipose tissue of mice with established obesity. Therefore, obese male wild-type C57B1/6 mice were treated with i.p. injection of DC101 (40 mg/kg body weight, twice weekly during 13 weeks) or of the control antibody 1C8. Treatment with DC101 resulted in a slightly lower body weight but had no effect on subcutaneous (SC) or gonadal (GON) white adipose tissue mass, as monitored by MRI. Histochemical analysis of isolated SC and GON fat pads did not reveal significant effects of DC101 treatment on adipocyte or blood vessel size or density. Plasma levels of the liver enzymes aspartate aminotransferase and alanine aminotransferase as well as liver triglyceride levels were significantly decreased following DC101 treatment. Plasma glucose levels were markedly lower upon DC101 treatment, whereas insulin and adiponectin levels were not affected. Furthermore, Akt phosphorylation in adipose tissues was not affected. Thus, in vivo VEGF-R2 blockade in mice with established nutritionally induced obesity did not significantly affect insulin signaling in adipose tissue or adiposity.
Methods To Obtain Quick Estimates of Formation Parameters in Interference Tests Derived From Features of the Line-Source Solution—Theory and Application
Authors: Maizeret Pierre-David
Published: February 2013

Interference testing is the oldest, but still the most effective, way of establishing communication between wells and determining the interwell-reservoir transmissibility. Yet these tests are not run frequently because often the results are difficult to analyze as a result of unforeseen complications.

This paper presents practical methods derived from the properties of the line-source solution that is used to design and interpret effective interference tests. In single-well transient tests, early-time features of the exponential integral function occur too early to be observed. However, these features appear much later in an interference test and can be used in an observation well to estimate the storativity and transmissibility ratios of the reservoir. The pressure response and the log derivative of the pressure intersect on the log-log diagnostic plot, and the pressure response itself exhibits an inflection point. With these characteristics, simple geometrical methods are proposed to estimate reservoir parameters. Moreover, a new expression of the “lag time,” or delay in the response, is formulated. The particular case of falloff or buildup is studied in detail, because the time lag in the reservoir response can bring extra information. A field example is included to demonstrate the application of these methods to actual data and their usefulness to a practicing well-test engineer.
The Physics of Frost Heave and Ice‐Lens Growth
Authors: Peppin Stephen S. L. , Style Robert W.
Published: February 2013

The principle cause of frost heave is the formation of segregated ice—ice lenses—in freezing soil columns. Despite much experimental and theoretical work, there remain many questions about the fundamental process by which this occurs. Frost‐heave models fall into two main classes: capillary and frozen‐fringe models. Which model is appropriate depends on whether there is a frozen fringe; these are difficult to observe but some experimental evidence does exist. Recent advances have revitalized the capillary model, such as the engulfment model and the concept of geometrical supercooling. Key experimental and theoretical challenges remain to be resolved.