bluuebunny/crossref_metadata_2025 huggingface dataset:
Using the Facebook group as a learning management system: An exploratory study
Authors: Wang Qiyun , Woo Huay Lit , Quek Choon Lang , Yang Yuqin , Liu Mei
Published: June 2011

Facebook is a popular social networking site. It, like many other new technologies, has potential for teaching and learning because of its unique built‐in functions that offer pedagogical, social and technological affordances. In this study, the Facebook group was used as a learning management system (LMS) in two courses for putting up announcements, sharing resources, organizing weekly tutorials and conducting online discussions at a teacher education institute in Singapore. This study explores using the Facebook group as an LMS and the students' perceptions of using it in their courses. Results showed that students were basically satisfied with the affordances of Facebook as the fundamental functions of an LMS could be easily implemented in the Facebook group. However, using the Facebook group as an LMS has certain limitations. It did not support other format files to be uploaded directly, and the discussion was not organized in a threaded structure. Also, the students did not feel safe and comfortable as their privacy might be revealed. Constraints of using the Facebook group as an LMS, implications for practice and limitations of this study are discussed.

Practitioner notes

What is already known about this topic

Facebook has been popularly used by tertiary students, but many students do not want their teachers to be friends on Facebook

Teacher's self‐disclosure on Facebook can promote classroom atmosphere, teacher's credibility and student–teacher relationship

Commercial learning management systems (LMSs) have limitations

What this paper adds

The Facebook group can be used an LMS as it has certain pedagogical, social and technological affordances

Students are satisfied with the way of using the Facebook group as an LMS

Younger students are more acceptable with the idea of using the Facebook group as an LMS

Using the Facebook group as an LMS has limitations: it does not support other format files; its discussions are not listed in threads; and it is not perceived as a safe environment

Implications for practice and/or policy

The Facebook group can be used an LMS substitute or supplement

Third‐party applications are needed to extend the capability of the Facebook group as an LMS

Using Facebook seems to be more appropriate for young learners than adults

Teachers do not have to be students' friends on Facebook.
Shell microstructure of the early bivalve Pojetaia and the independent origin of nacre within the mollusca
Authors: VENDRASCO MICHAEL J. , CHECA ANTONIO G. , KOUCHINSKY ARTEM V.
Published: June 2011

Abstract:  Pojetaia and Fordilla are the oldest bivalve molluscs, occurring in roughly co‐eval rocks from the Tommotian, and are the only undisputed, well‐known bivalves from the Cambrian. New specimens reveal that Pojetaia had a laminar inner shell microstructure reminiscent of the foliated aragonite of modern monoplacophorans, and the same is true for Fordilla. A similar shell microstructure is seen in Anabarella and Watsonella, providing support for the hypothesis that they are the ancestors of bivalves. Foliated aragonite shares many similarities with nacre, and it may have been the precursor to nacre in bivalves. No cases of undisputed nacre occur in the Cambrian, in spite of much shell microstructure data from molluscs of this time period. Thus, although considered by many to be homologous among molluscs, we conclude that nacre convergently evolved in monoplacophorans, gastropods, bivalves, and cephalopods. This independent origin of nacre appears to have taken place during, or just prior to, the Great Ordovician Biodiversification Event and represents a significant step in the arms race between predators and molluscan prey.
Is Consociational Theory the Answer to Global Conflict? From the Netherlands to Northern Ireland and Iraq
Authors: Dixon Paul
Published: June 2011

Neo-conservatives and liberal interventionists subscribe to the idealistic belief that external powers can successfully re-engineer states into Western capitalist democracies. Consociationalism is a prominent or even dominant theory for managing conflict in ‘ethnonationally divided societies’. The consociational model is based on the Dutch experience of managing ‘plural conflict’ from 1917 to 1967. This article argues that consociationalism has become increasingly vague, ambiguous and even contradictory as the theory has been stretched in an attempt to claim relevance to both the Northern Ireland and Iraq conflicts. Although this has eroded the coherence of the consociational theory this is more than compensated for by the flexibility this gives consociationalists in marketing their concept as all things to all people. By contrast post-structuralist radical democrats are critical of the reductionism of consociational theorising and emphasise the limits of human reason to grasp adequately the complexity of diverse conflict situations.
Brain‐derived neurotrophic factor induces proliferation of human airway smooth muscle cells
Authors: Aravamudan Bharathi , Thompson Michael , Pabelick Christina , Prakash Y. S.
Published: June 2011

Airway diseases such as asthma involve increased airway smooth muscle (ASM) contractility and remodelling via enhanced proliferation. Neurotrophins (NTs) such as brain‐derived neurotrophic factor (BDNF), well‐known in the nervous system, can regulate Ca2+ signalling, and interact with cytokines in contributing to airway hyperreactivity. In this study, we determined whether and how BDNF regulates human ASM cell proliferation in the presence of inflammation, thus testing its potential role in airway remodelling. Cells were treated with 10 nM BDNF, 25 ng/ml tumour necrosis factor (TNF‐α) or interleukin‐13 (IL‐13), or 10 ng/ml platelet‐derived growth factor (PDGF). Proliferation was measured using CyQuant dye, with immunoblotting of cell cycle proteins predicted to change with proliferation. Forty‐eight hours of BDNF enhanced ASM proliferation to ∼50% of that by PDGF or cytokines. Transfection with small interfering RNAs (siRNAs) targeting high‐affinity tropomyosin‐related kinase B receptor abolished BDNF effects on proliferation, whereas low‐affinity 75 kD neurotrophin receptor (p75NTR) siRNA had no effect. Systematic pharmacologic inhibition of different components of ERK1/2 and PI3K/Akt1 pathways blunted BDNF or TNF‐α–induced proliferation. BDNF also induced IκB phosphorylation and nuclear translocation of p50 and p65 NF‐κB subunits, with electron mobility shift assay confirmation of NF‐κB binding to consensus DNA sequence. These results demonstrate that NTs such as BDNF can enhance human ASM cell proliferation by activating proliferation‐specific signalling pathways and a versatile transcription factor such as NF‐κB, which are common to cytokines and growth factors involved in asthma.
Pregnancy worries: a longitudinal study of Spanish women
Authors: PEÑACOBA‐PUENTE CECILIA , MONGE FRANCISCO JAVIER CARMONA , MORALES DOLORES MARÍN
Published: June 2011

Objective. To identify pregnancy worries in women by assessing the intensity of these worries and how they change over the course of pregnancy, as well as their relations with sociodemographic and clinical variables. Design. Longitudinal study using a postal questionnaire. Setting. University hospital in Madrid. Population. 285 pregnant women. Method. Women were asked about their pregnancy‐specific worries in their first trimester (mean gestational age 14.4 weeks) and third trimester (mean gestational age 34.3 weeks). Main Outcome Measures. The women completed a questionnaire that included sociodemographic information and the Cambridge Worry Scale. Results. Pregnancy worries were significantly reduced during the third trimester. The main concern throughout gestation was worry about fetal health. Multiparity and pregnancy planning protected women from pregnancy worries, whereas having had a miscarriage had a negative effect. A younger age and being employed contributed to greater socioeconomic worries. Conclusions. Worries related to the health of the fetus are universal across different nationalities. A first pregnancy, unplanned pregnancy, and previous miscarriage are risk factors that influence the intensity of a woman's worries. To improve the health and quality of life of pregnant women, a holistic approach to their care should include evaluation of their worries and appropriate intervention in particular groups considered at risk.
Algal biochar: effects and applications
Authors: BIRD MICHAEL I. , WURSTER CHRISTOPHER M. , DE PAULA SILVA PEDRO H. , PAUL NICHOLAS A. , DE NYS ROCKY
Published: June 2011

Algae represent a promising target for the generation of bioenergy through slow pyrolysis, leading to the production of biochar. This study reports experiments conducted on the production of freshwater and saltwater macroalgal biochar in pilot‐scale quantities, the physical and chemical characteristics of the biochars, and their impact on plant growth. The biochars are low in carbon (C) content, surface area and cation exchange capacity, while being high in ash and nutrients. Trace element analysis demonstrates that macroalgal biochar produced from unpolluted water does not contain toxic trace elements in excess of levels mandated for unrestricted use as a biosolids amendment to soils. Pot trials conducted using a C and nutrient‐poor soil, without and with additional fertilizer, demonstrate dramatic increases between 15 and 32 times, respectively, in plant growth rate for biochar treatments compared with the no biochar controls, with additional smaller increases when fertilizer was added. Pot trials conducted using a relatively fertile agricultural soil showed smaller but significant impacts of biochar amendment over the controls.
Price and Service Competition in an Outsourced Supply Chain
Authors: Jin Yue , Ryan Jennifer K.
Published: June 2011

We consider a buyer who outsources the manufacturing of a product to multiple symmetric make‐to‐stock suppliers who compete on price and service (fill rate). The buyer allocates demand to the suppliers using a score function with an exponential form, which specifies the relative importance of price vs. service, in order to minimize his costs, while the suppliers choose their prices and fill rates to maximize their profits. For the case of dual‐sourcing, we characterize the optimal parameter of the exponential score function, considering the impact of the buyer's decisions on the suppliers, and considering how the suppliers compete against each other to earn a portion of the buyer's demand. We prove the existence of a unique equilibrium and characterize the equilibrium behavior of the system. We then consider a general number of suppliers and show that the equilibrium prices and fill rates, and the buyer's cost, are increasing in the number of suppliers. We compare these results to a model of single‐sourcing, in which the buyer is the Stackelberg leader and extracts all profits from the supplier. We find that the buyer always prefers single‐sourcing to multisourcing. Finally, we study a centralized system and use the results to develop a coordinating contract for the decentralized system.
Sildenafil improves diabetic vascular activity through suppressing endothelin receptor A, iNOS and NADPH oxidase which is comparable with the endothelin receptor antagonist CPU0213 in STZ-injected rats
Authors: Luo Lu , Dai De-Zai , Cheng Yu-Si , Zhang Qi , Yuan Wen-Jun , Dai Yin
Published: June 2011

Objectives

Abnormal vascular activity in diabetes is related not only to impaired nitric oxide bioavailability but also to inflammatory cytokines, endothelin A receptor (ETA) activation and NADPH oxidase in the vasculature. The potential role of sildenafil in improving vascular function was investigated. Its action was likely blocking upregulated ETA and NADPH oxidase, and was compared with the endothelin receptor antagonist CPU0213.

Methods

Diabetes was induced by single-dose administration of streptozotocin (65 mg/kg, i.p.) to rats and the vascular activity of the thoracic aorta was measured.

Key findings

An increase in contractile tone to phenylephrine and a decrease in relaxant tone to acetylcholine was found in the thoracic aorta. Oxidative stress was evident by increased malondialdehyde and reduced glutathione peroxidase levels in serum and upregulation of ETA, MMP-9 (matrix metalloproteinase-9), inducible nitric oxide synthase and NADPH oxidase p67phox were found in the vascular wall. The vascular abnormalities and abnormal biomarkers were attenuated significantly by either sildenafil or CPU0213 along with an improvement of nitric oxide bioavailability and vascular activity.

Conclusions

Improvement of diabetic vascular abnormal activity by sildenafil results from its suppression of activation of ETA and NADPH oxidase in the vasculature, and these actions are comparable with those of the endothelin receptor antagonist CPU0213.
The Identification of the Key Enablers for Force Control of Robotic Friction Stir Welding
Authors: Longhurst William R. , Strauss Alvin M. , Cook George E.
Published: June 2011

Friction stir welding (FSW) is a solid state welding process that uses a rotating tool to plastically deform and then forge together materials. This process requires a large axial force to be maintained on the tool as the tool is plunged into the work piece and traversed along the weld seam. Force control is required if robots are to be used. Force control provides compensation for the compliant nature of robots. Without force control, welding flaws would continuously emerge as the robot repositioned its linkages to traverse the tool along the weld seam. Insufficient plunge depth would result and cause the welding flaws as the robot’s linkages yielded from the resulting force in welding environment. As FSW continues to emerge in manufacturing, robotic applications will be desired to establish flexible automation. The research presented here identifies the key enablers for successful and stable force control of FSW. To this end, a FSW force controller was designed and implemented on a retrofitted Milwaukee Model K milling machine. The closed loop proportional, integral plus derivative control architecture was tuned using the Ziegler–Nichols method. Welding experiments were conducted by butt welding 0.25 in. (6.35 mm) × 1.50 in. (38.1 mm) × 8.0 in. (203.2 mm) samples of aluminum 6061 with a 0.25 in. (6.35 mm) threaded tool. The experimental force control system was able to regulate to a desired force with a standard deviation of 129.4 N. From the experiments, it was determined that tool geometry and position are important parameters influencing the performance of the force controller, and four key enablers were identified for stable force control of FSW. The most important enabler is the maintaining of the position of a portion of the tool’s shoulder above the work piece surface. When the shoulder is completely submerged below the surface, an unstable system occurs. The other key enablers are a smooth motion profile, an increased lead angle, and positional constraints for the tool. These last three enablers contribute to the stability of the system by making the tool’s interaction with the nonlinear welding environment less sensitive. It is concluded that successful implementation of force control in the robotic FSW systems can be obtained by establishing and adhering to these key enablers. In addition, force control via plunge depth adjustment reduces weld flash and improves the appearance of the weld.
Harnessing the Glucosyltransferase Activities of Clostridium difficile for Functional Studies of Toxins A and B
Authors: Darkoh Charles , Kaplan Heidi B. , DuPont Herbert L.
Published: June 2011

The incidence of
Clostridium difficile
infection (CDI) has been increasing within the last decade. Pathogenic strains of
C. difficile
produce toxin A and/or toxin B, which are important virulence factors in the pathogenesis of this bacterium. Current methods for diagnosing CDI are mostly qualitative tests that detect either the bacterium or the toxins. We have developed an assay (Cdifftox activity assay) to detect
C. difficile
toxin A and B activities that is quantitative and cost-efficient and utilizes a substrate that is stereochemically similar to the native substrate of the toxins (UDP-glucose). To characterize toxin activity, toxins A and B were purified from culture supernatants by ammonium sulfate precipitation and chromatography through DEAE-Sepharose and gel filtration columns. The activities of the final fractions were quantitated using the Cdifftox activity assay and compared to the results of a toxin A- and B-specific enzyme-linked immunosorbent assay (ELISA). The affinity for the substrate was >4-fold higher for toxin B than for toxin A. Moreover, the rate of cleavage of the substrate was 4.3-fold higher for toxin B than for toxin A. The optimum temperature for both toxins ranged from 35 to 40°C at pH 8. Culture supernatants from clinical isolates obtained from the stools of patients suspected to be suffering from CDI were tested using the Cdifftox activity assay, and the results were compared to those of ELISA and PCR amplification of the toxin genes. Our results demonstrate that this new assay is comparable to the current commercial ELISA for detecting the toxins in the samples tested and has the added advantage of quantitating toxin activity.
Incidence of Moxifloxacin Resistance in Clinical Mycobacterium tuberculosis Isolates in Houston, Texas
Authors: El Sahly Hana M. , Teeter Larry D. , Jost Kenneth C. , Dunbar Denise , Lew Justin , Graviss Edward A.
Published: June 2011

Comprehensive data on the prevalence of quinolone resistance in
Mycobacterium tuberculosis
clinical isolates in the United States are scarce. By use of a systematic population-based approach,
M. tuberculosis
strains from tuberculosis (TB) cases were collected in Harris County, TX, in 2007 to 2008. The susceptibilities of
M. tuberculosis
isolates to moxifloxacin and ofloxacin were determined by the agar proportion indirect susceptibility method. Spoligotyping and 12-locus mycobacterial interspersed repetitive unit (MIRU12)-based genotyping of
M. tuberculosis
isolates were performed, and the
gyrA
,
gyrB
, Rv2686c, Rv2687c, and Rv2688c genes in quinolone-resistant and year-of-diagnosis-matched
M. tuberculosis
isolates were sequenced. Susceptibility testing was performed on 557
M. tuberculosis
isolates, of which 10 (1.8%) were resistant to moxifloxacin. There was 100% concordance between ofloxacin and moxifloxacin susceptibilities. A quinolone was prescribed to at least 5 (50%) patients in the period preceding TB diagnosis. Multidrug-resistant TB (MDR-TB) was significantly associated with quinolone resistance (
P
= 0.01). Mutations in the quinolone resistance-determining region of
gyrA
were found for 50% of the resistant isolates. No other presumptive quinolone resistance-associated mutations were identified. We conclude that the incidence of moxifloxacin-resistant TB is low in Harris County and is associated with MDR-TB. Previous exposure to quinolones is common among patients with moxifloxacin resistance and warrants more careful evaluation.
Prototheca wickerhamii Mimicking Yeast: a Cautionary Tale
Authors: McMullan B. , Muthiah K. , Stark D. , Lee L. , Marriott D.
Published: June 2011

Prototheca
spp. are environmental algae that may cause serious infection in the immunocompromised patient. Clinical manifestations may mimic other diseases. We present a case of fatal infection in a 78-year-old cardiac transplant recipient and discuss pitfalls in the clinical and laboratory diagnoses.
Identification by 16S rRNA Gene Sequencing of Negativicoccus succinicivorans Recovered from the Blood of a Patient with Hemochromatosis and Pancreatitis
Authors: Church D. L. , Simmon K. E. , Sporina Jan , Lloyd T. , Gregson D. B.
Published: June 2011

We describe a case of
Negativicoccus succinicivorans
bacteremia in an adult man with hemochromatosis and acute pancreatitis. Conventional phenotypic tests and commercial identification systems failed to definitively identify the tiny anaerobic Gram-negative coccus isolated from two sets of blood cultures. The bacterium was identified by 16S rRNA gene sequencing and analysis using the SmartGene Integrated Database Network System software. This is the first published report of the recovery of this organism from a patient with invasive infection.
The HIV-1-Specific Protein Casp8p41 Induces Death of Infected Cells through Bax/Bak
Authors: Sainski Amy M. , Natesampillai Sekar , Cummins Nathan W. , Bren Gary D. , Taylor Julie , Saenz Dyana T. , Poeschla Eric M. , Badley Andrew D.
Published: June 2011

Casp8p41, a novel protein generated when HIV-1 protease cleaves caspase 8, independently causes NF-κB activation, proinflammatory cytokine production, and cell death. Here we investigate the mechanism by which Casp8p41 induces cell death. Immunogold staining and electron microscopy demonstrate that Casp8p41 localizes to mitochondria of activated primary CD4 T cells, suggesting mitochondrial involvement. Therefore, we assessed the dependency of Casp8p41-induced death on Bax/Bak and caspase 9. In wild-type (WT) mouse embryonic fibroblast (MEF) cells, Casp8p41 causes rapid mitochondrial depolarization (
P
< 0.001), yet Casp8p41 expression in Bax/Bak double-knockout (DKO) MEF cells does not. Similarly, caspase 9-deficient T cells (JMR cells), which express Casp8p41, undergo minimal cell death, whereas reconstituting these cells with caspase 9 (F9 cells) restores Casp8p41 cytotoxicity (
P
< 0.01). The infection of caspase 9-deficient cells with a green fluorescent protein (GFP) HIV-1 reporter virus results in cell death in 32% of infected GFP-positive cells, while the restoration of caspase 9 expression in these cells restores infected-cell killing to 68% (
P
< 0.05), with similar levels of viral replication between infections. Our data demonstrate that Casp8p41 requires Bax/Bak to induce mitochondrial depolarization, which leads to caspase 9 activation following either Casp8p41 expression or HIV-1 infection. This understanding allows the design of strategies to interrupt this form of death of HIV-1-infected cells.
The 6-PACK programme to decrease fall-related injuries in acute hospitals: protocol for a cluster randomised controlled trial: Figure 1
Authors: Barker Anna , Brand Caroline , Haines Terry , Hill Keith , Brauer Sandy , Jolley Damien , Botti Mari , Cumming Robert , Livingston Patricia M , Sherrington Cathie , Zavarsek Silva , Morello Renata , Kamar Jeannette
Published: June 2011

Background and aims

In-hospital fall-related injuries are a source of personal harm, preventable hospitalisation costs, and access block through increased length of stay. Despite increased fall prevention awareness and activity over the last decade, rates of reported fall-related fractures in hospitals appear not to have decreased. This cluster randomised controlled trial (RCT) aims to determine the efficacy of the 6-PACK programme for preventing fall-related injuries, and its generalisability to other acute hospitals.

Methods

24 acute medical and surgical wards from six to eight hospitals throughout Australia will be recruited for the study. Wards will be matched by type and fall-related injury rates, then randomly allocated to the 6-PACK intervention (12 wards) or usual care control group (12 wards). The 6-PACK programme includes a nine-item fall risk assessment and six nursing interventions: ‘falls alert’ sign; supervision of patients in the bathroom; ensuring patient's walking aids are within reach; establishment of a toileting regime; use of a low-low bed; and use of bed/chair alarm. Intervention wards will be supported by a structured implementation strategy. The primary outcomes are fall and fall-related injury rates 12 months following 6-PACK implementation.

Discussion

This study will involve approximately 16 000 patients, and as such is planned to be the largest hospital fall prevention RCT to be undertaken and the first to be powered for the important outcome of fall-related injuries. If effective, there is potential to implement the programme widely as part of daily patient care in acute hospital wards where fall-related injuries are a problem.

Trial registration

The protocol for this study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12611000332921).
Some Jewish thoughts on genetic enhancement
Authors: Glick Shimon M
Published: June 2011

The issues of the ethics of germ line modification in general and of enhancement by germ line modification in particular have been the subject of hundreds of articles in the bioethical literature. Both because the techniques are far from perfected and because the potential long term side effects are unkown, there is a widespread consensus that germ line modification for enhancement is absolutely unethical and beyond the pale at the present time.

The author considers a thought expperiment projecting into the future in which perhaps the safety and reversibility of germ line modification have been clearly demonstrated. Under such circumstances it is contended that the dividing line between treatment and enhancement is difficult and indeed perhaps impossible to maintain.

The Jewish tradition is examined and from the various sources cited it would seem that the benefits of certain kinds of genetic enhancements might well outweigh the objections to such manipulations.
Treatment of two blood blister-like aneurysms with flow diverter stenting
Authors: Consoli Arturo , Nappini Sergio , Renieri Leonardo , Limbucci Nicola , Ricciardi Fabrizio , Mangiafico Salvatore
Published: June 2011

Purpose

Neurosurgical and endovascular treatment of fragile and recurrent aneurysms of the non-branching portion of the internal carotid artery, known as blister-like aneurysms, is challenging. The aim of this paper is to describe two cases of ruptured blister-like aneurysms of the internal carotid artery and of the vertebral artery at the origin of the postero-inferior cerebellar artery, which were both treated with flow diverter (FD) stents.

Methods

Two patients with a sub-arachnoid hemorrhage secondary to the rupture of a blister-like aneurysm were treated with a Pipeline (ev3, Irvine, California, USA) stent. Digital subtraction angiography and clinical follow-up were carried out.

Results

Both patients treated with FD stents had an excellent clinical (modified Rankin Scale, mRS 0) and angiographic outcome. In both cases the aneurysms were completely excluded after 6 months.

Conclusions

Although the use of this endovascular approach is still debated because of poor experience and pharmacological limitations, FD stents may represent a valid alternative approach for treatment of this aneurysm subtype.
Cerebellar hemangioblastoma supplied by persistent hypoglossal artery: Figure 1
Authors: Binning Mandy J , Siddiqui Adnan H
Published: June 2011

The authors report a unique case of an intramedullary cerebellar hemangioblastoma that was supplied by a persistent hypoglossal artery. In this case, recognition of the persistent hypoglossal artery through angiographic imaging was crucial in identifying tumor blood supply and in guiding the decision to perform a craniotomy without tumor embolization.
GOVERNING EQUATIONS AND GENERAL SOLUTIONS OF PLANE ELASTICITY OF TWO-DIMENSIONAL DECAGONAL QUASICRYSTALS
Authors: GAO YANG , SHANG LAN-GE
Published: June 2011

Two-dimensional problem is systematically investigated for the coupled equations in two-dimensional decagonal quasicrystals, and three general solutions are presented by an operator method. To simplify governing equations, each general solution shall take three different forms expressed in terms of three displacement functions, which satisfy partial three differential equations of second order. To illustrate its utility, the closed-form solutions are obtained for problems of point phonon forces and phason force acting at the apex of a quasicrystal wedge, all in terms of the general solutions. Furthermore, these solutions can be degenerated to those of problems of point forces applied on the boundary of a quasicrystal half-plane.
SOL-GEL SYNTHESIS AND CHARACTERIZATION OF COPPER STABILIZED ZIRCONIA NANOPARTICLES
Authors: VAHIDSHAD Y. , ABDIZADEH H. , BAHARVANDI H. R. , AKBARI BASERI M.
Published: June 2011

A sol-gel method is investigated to synthesize CuO – ZrO 2 nanoparticles as catalyst for hydrogen production from methanol. Finer precursor nanoparticles give rise to larger specific areas in catalyst which result in a high hydrogen production. The effects of some critical process parameters on the sol-gel synthesis of CuO – ZrO 2 nanoparticles are studied. These parameters are affected on synthesis of CuO – ZrO 2 when it is prepared with sol-gel method. Particle size and distribution are considered as the results. The parameters including the effect of calcination temperature, aging temperature, nature and concentration of catalyst (acidic or basic conditions), H 2 O /precursor molar ratio, and chelating agent that have been identified as most important, are focused. It is found that the calcination temperature strongly influenced the morphology and interaction between the active species and support, and hence the structure and catalytic performance. Nature and concentration of catalyst ( pH value), chelating agent, ( H 2 O /precursor) molar ratio and also aging temperature have influence on the nanoparticles. Thus, by controlling these factors, it is possible to vary the morphology and properties of the sol-gel-derived inorganic network over wide ranges. Morphology, particle size and distribution, phase evaluation, structure, and chemical analysis of the products are investigated by SEM, TEM, DTA/TG, XRD and EDX respectively.
PAIRWISE ENTANGLEMENT IN THE N-QUBIT XX MODEL WITH DZYALOSHINSKI–MORIYA INTERACTION AND MAGNETIC FIELD
Authors: ZHOU BIN
Published: June 2011

In this paper, we investigate the role of Dzyaloshinski–Moriya (DM) interaction in the pairwise entanglement in the three- and four-qubit XX models with magnetic field. In the four-qubit model, the pairwise entanglements of two nearest-neighbor qubits and two next-neighbor qubits are investigated, respectively. The dependences of the critical temperature at which the pairwise thermal entanglement disappears on DM interaction and magnetic fields are studied in details. At zero temperature, the entanglement can undergo sudden changes with adjustment of the parameters, and the general results of the concurrence are obtained in all cases.
$\mathcal{H}_{\infty}$ LAG SYNCHRONIZATION FOR CHAOTIC SYSTEMS
Authors: AHN CHOON KI
Published: June 2011

In this paper, we propose a new [Formula: see text] lag synchronization scheme for a general class of chaotic systems with external disturbance. Based on Lyapunov theory and linear matrix inequality (LMI) approach, the [Formula: see text] lag synchronization controller is presented to not only guarantee exponential lag synchronization but also reduce the effect of external disturbance to an [Formula: see text] norm constraint. The proposed controller can be obtained by solving a convex optimization problem represented by the LMI. As an application of the proposed method, the [Formula: see text] lag synchronization problem for Genesio–Tesi system is investigated.
SYNTHESIS AND STRUCTURAL/MICROSTRUCTURAL CHARACTERISTICS OF Zn-DOPED Tl-BASED HIGH-Tc SUPERCONDUCTORS
Authors: YADAV B. S. , VERMA G. D. , PHASE D. M. , LALLA N. P. , DAS B.
Published: June 2011

Bulk superconducting samples of type Tl 2 Ba 2 Ca n-1 Cu n-x Zn x O 8 (where n = 2, 3 and x = 0, 0.1, 0.25, 0.50) were prepared by standard ceramic method. The gross structural characteristics/phase identification of the as synthesized samples were carried out by powder X-ray diffraction technique. The microstructural characteristics of these samples were explored by scanning electron microscopic and transmission electron microscopic techniques. The chemical compositions of these samples were determined by energy dispersive analysis of X-rays technique. The powder X-ray diffraction patterns indicate that the lattice parameter "c" vary and "a" showed no regular variation but the gross structure of Tl-2212 and Tl-2223 remain tetragonal with Zn substitution upto 0.50. The transition temperature (Tc) measured by standard four-probe method decreases as x increases from 0 to 0.50. The transport critical density (Jc) values were also measured by standard four-probe method as potential difference of 1 μV/cm appears across the sample by increasing current. The electron microscopic explorations exhibit various structural features (stacking faults and uniform distribution of ZnO nanoparticles) which improve the physical properties (e.g., transport critical current density "Jc") of these superconductors. The observed enhancement in transport critical current densities (Jc) of at least one order of magnitude (from 102 to 103 A/cm 2) is due to the uniform distribution of ZnO nanoparticles which act as flux pinning centres.
INFORMATION TRANSFER IN THE GENERALIZED SYNCHRONIZATION
Authors: WANG MOGEI , WANG XINGYUAN , LIU ZHENZHEN
Published: June 2011

We use symbolic dynamics to investigate the transfer of information between the dissipative coupled nonidentical oscillators exhibiting the generalized synchronization. It is found that the drive information is injected into the response state and stored reversely in it. Moreover, the injection and storage give new meanings to the conditional Lyapunov exponent from the view of the information.
INTERSECTIONS OF CERTAIN DELETED DIGITS SETS
Authors: PEDERSEN STEEN , PHILLIPS JASON D.
Published: June 2011

We consider some properties of the intersection of deleted digits Cantor sets with their translates. We investigate conditions on the set of digits such that, for any t between zero and the dimension of the deleted digits Cantor set itself, the set of translations such that the intersection has that Hausdorff dimension equal to t is dense in the set F of translations such that the intersection is non-empty. We make some simple observations regarding properties of the set F, in particular, we characterize when F is an interval, in terms of conditions on the digit set.
CONNECTIVITY PROPERTIES OF SIERPIŃSKI RELATIVES
Authors: TAYLOR T. D.
Published: June 2011

This paper presents a study of the connectivity of the class of fractals known as the Sierpiński relatives. These fractals all have the same fractal dimension, but different topologies. Some are totally disconnected, some are disconnected but with paths, some are simply-connected, and some are multiply-connected. Conditions for these four cases are presented. Constructions of paths, including non-contractible closed paths in the case of multiply-connected relatives, are presented. Examples of specific relatives are provided to illustrate the four cases.
Leukocyte rolling and adhesion both contribute to regulation of microvascular permeability to albumin via ligation of ICAM-1
Authors: Sumagin Ronen , Kuebel Julia M. , Sarelius Ingrid H.
Published: June 2011

Activated neutrophils interacting with the vessel wall can alter vascular permeability to macromolecules such as albumin via release of various secretion products that induce changes in the endothelial monolayer. In the current work we used cremaster microvessels of anesthetized mice to show that, in addition to this paracrine mechanism, leukocyte ligation of endothelial ICAM-1 directly activates endothelial cell (EC) signaling, altering EC permeability to albumin [i.e., solute permeability ( Ps)]. We show that antibody cross-linking of surface ICAM-1 in intact microvessels is sufficient to increase Ps even in the absence of interacting leukocytes. Unstimulated arterioles do not support leukocyte-EC interactions, but despite this, antibody ligation of ICAM-1 in these vessels induced a twofold increase in Ps. Similarly, in venules that were depleted of interacting neutrophils, Ps was decreased to below resting levels and was restored by ligation of ICAM-1. Use of function-blocking antibodies to separately block leukocyte rolling or adhesion under unstimulated or TNF-α-activated conditions established that both rolling and adhered leukocytes contribute to Ps regulation in situ. Both rolling and adhesion activated EC-dependent signaling mechanisms that increased Ps. ICAM-1 ligation with primary antibody alone or primary followed by secondary antibodies showed that regulation of Ps is directly dependent on the degree of ICAM-1 clustering. Under physiological versus inflamed conditions, respectively, this ICAM-1 clustering-dependent regulation of Ps switches from PKC dependent and Src independent to Src dependent and PKC independent. This study thus identifies a new mechanism by which antiadhesion treatment may constitute a potential therapy for tissue edema.
Grasping with the eyes
Authors: Ambrosini Ettore , Costantini Marcello , Sinigaglia Corrado
Published: June 2011

When observing someone else acting on an object, people implement goal-specific eye movement programs that are driven by their own motor representation of the observed action. Usually, however, we observe people acting in contexts where more objects, different in shape and size, are present. Is our brain able to select the intended target even when there are different objects in the visual scene? And if this is the case, what kind of information does our motor system capitalize on? We recorded eye movements while participants observed an actor reaching for and grasping one of two objects requiring two different kinds of grip to be picked up. In a control condition, the actor merely reached for and touched one of the two objects without preshaping her hand according to the target features. Results showed higher accuracy and earlier saccadic movements when participants observed an actually grasping hand than when they observed a mere reaching hand devoid of any kind of target-related preshaping. This clearly suggests that the hand preshaping provided the observer with enough motor cues to proactively and reliably saccade toward the object to be grasped, thus identifying it even when the action target was not previously known. Our findings strongly corroborate the direct matching hypothesis suggesting that in processing others' actions, we take advantage of the same motor knowledge that enables us to efficiently perform those actions.
Dopamine triggers skeletal muscle tone by activating D1-like receptors on somatic motoneurons
Authors: Schwarz Peter B. , Peever John H.
Published: June 2011

The dopamine system plays an integral role in motor physiology. Dopamine controls movement by modulation of higher-order motor centers (e.g., basal ganglia) but may also regulate movement by directly controlling motoneuron function. Even though dopamine cells synapse onto motoneurons, which themselves express dopamine receptors, it is unknown whether dopamine modulates skeletal muscle activity. Therefore, we aimed to determine whether changes in dopaminergic neurotransmission at a somatic motor pool affect motor outflow to skeletal muscles. We used microinjection, neuropharmacology, electrophysiology, and histology to determine whether manipulation of D1- and D2-like receptors on trigeminal motoneurons affects masseter and/or tensor palatini muscle tone in anesthetized rats. We found that apomorphine (a dopamine analog) activated trigeminal motoneurons and triggered a potent increase in both masseter and tensor palatini tone. This excitatory effect is mediated by D1-like receptors because specific D1-like receptor activation strengthened muscle tone and blockade of these receptors prevented dopamine-driven activation of motoneurons. Blockade of D1-like receptors alone had no detectable effect on basal masseter/tensor palatini tone, indicating the absence of a functional dopamine drive onto trigeminal motoneurons, at least during isoflurane anesthesia. Finally, we showed that D2-like receptors do not affect either trigeminal motoneuron function or masseter/tensor palatini muscle tone. Our results provide the first demonstration that dopamine can directly control movement by manipulating somatic motoneuron behavior and skeletal muscle tone.
Common muscle synergies for control of center of mass and force in nonstepping and stepping postural behaviors
Authors: Chvatal Stacie A. , Torres-Oviedo Gelsy , Safavynia Seyed A. , Ting Lena H.
Published: June 2011

We investigated muscle activity, ground reaction forces, and center of mass (CoM) acceleration in two different postural behaviors for standing balance control in humans to determine whether common neural mechanisms are used in different postural tasks. We compared nonstepping responses, where the base of support is stationary and balance is recovered by returning CoM back to its initial position, with stepping responses, where the base of support is enlarged and balance is recovered by pushing the CoM away from the initial position. In response to perturbations of the same direction, these two postural behaviors resulted in different muscle activity and ground reaction forces. We hypothesized that a common pool of muscle synergies producing consistent task-level biomechanical functions is used to generate different postural behaviors. Two sets of support-surface translations in 12 horizontal-plane directions were presented, first to evoke stepping responses and then to evoke nonstepping responses. Electromyographs in 16 lower back and leg muscles of the stance leg were measured. Initially (∼100-ms latency), electromyographs, CoM acceleration, and forces were similar in nonstepping and stepping responses, but these diverged in later time periods (∼200 ms), when stepping occurred. We identified muscle synergies using non-negative matrix factorization and functional muscle synergies that quantified correlations between muscle synergy recruitment levels and biomechanical outputs. Functional muscle synergies that produce forces to restore CoM position in nonstepping responses were also used to displace the CoM during stepping responses. These results suggest that muscle synergies represent common neural mechanisms for CoM movement control under different dynamic conditions: stepping and nonstepping postural responses.
Somatosensory response properties of excitatory and inhibitory neurons in rat motor cortex
Authors: Murray Peter D. , Keller Asaf
Published: June 2011

In sensory cortical networks, peripheral inputs differentially activate excitatory and inhibitory neurons. Inhibitory neurons typically have larger responses and broader receptive field tuning compared with excitatory neurons. These differences are thought to underlie the powerful feedforward inhibition that occurs in response to sensory input. In the motor cortex, as in the somatosensory cortex, cutaneous and proprioceptive somatosensory inputs, generated before and during movement, strongly and dynamically modulate the activity of motor neurons involved in a movement and ultimately shape cortical command. Human studies suggest that somatosensory inputs modulate motor cortical activity in a center excitation, surround inhibition manner such that input from the activated muscle excites motor cortical neurons that project to it, whereas somatosensory input from nearby, nonactivated muscles inhibit these neurons. A key prediction of this hypothesis is that inhibitory and excitatory motor cortical neurons respond differently to somatosensory inputs. We tested this prediction with the use of multisite extracellular recordings in anesthetized rats. We found that fast-spiking (presumably inhibitory) neurons respond to tactile and proprioceptive inputs at shorter latencies and larger response magnitudes compared with regular-spiking (presumably excitatory) neurons. In contrast, we found no differences in the receptive field size of these neuronal populations. Strikingly, all fast-spiking neuron pairs analyzed with cross-correlation analysis displayed common excitation, which was significantly more prevalent than common excitation for regular-spiking neuron pairs. These findings suggest that somatosensory inputs preferentially evoke feedforward inhibition in the motor cortex. We suggest that this provides a mechanism for dynamic selection of motor cortical modules during voluntary movements.
Leukemia Inhibitory Factor Downregulates Human Papillomavirus-16 Oncogene Expression and Inhibits the Proliferation of Cervical Carcinoma Cells
Authors: Bay Joseph M. , Patterson Bruce K. , Teng Nelson N. H.
Published: June 2011

The constitutive proliferation and resistance to differentiation and apoptosis of neoplastic cervical cells depend on sustained expression of human papillomavirus oncogenes. Inhibition of these oncogenes is a goal for the prevention of progression of HPV-induced neoplasias to cervical cancer. SiHa cervical cancer cells were transfected with an HPV-16 promoter reporter construct and treated with leukemia inhibitory factor (LIF), a human cytokine of the interleukin 6 superfamily. SiHa and CaSki cervical cancer cells were also assessed for proliferation by MTT precipitation, programmed cell death by flow cytometry, and HPV E6 and E7 expression by real-time PCR. LIF-treated cervical cancer cells showed significantly reduced HPV LCR activation, reduced levels of E6 and E7 mRNA, and reduced proliferation. We report the novel use of LIF to inhibit viral oncogene expression in cervical cancer cells, with concomitant reduction in proliferation suggesting re-engagement of cell-cycle regulation.
Assessment of Glucagon-Like Peptide-1 Analogue and Renin Inhibitor on the Binding and Regulation of GLP-1 Receptor in Type 1 Diabetic Rat Hearts
Authors: Artinian Shushan B. , Al Lafi Sawsan M. , Boutary Suzan S. , Bitar Khalil M. , Zwainy Nadine S. , Bikhazi Anwar B.
Published: June 2011

This study focuses on the effects of long-term renin-angiotensin system suppression and/or incretin mimetic therapies on the regulation and binding affinity of GLP-1 to its receptor in the coronary endothelium (CE) and cardiomyocytes (CMs) of type 1 diabetic male Sprague-Dawley rats. The groups assessed are normal (N), streptozotocin-induced diabetic (D), Insulin treated (DI), Exendin-4 treated (DE), Aliskiren treated (DA), cotreated with Insulin and Aliskiren (DIA) and cotreated with exendin-4 and Aliskiren (DEA). Heart perfusion with125I-GLP-1 was performed to estimate GLP-1 binding affinity () to its receptor in the heart. Western Blotting was assessed to determine the expression variation of GLP-1 receptor in the heart. Plasma GLP-1 levels were measured using Enzyme-Linked Immunosorbent Assay (ELISA). Diabetes decreased the value on CE and increased it on CMs compared to normal. The combination of Exendin-4 with Aliskiren showed a normalizing effect on the binding affinity of GLP-1 at the coronary endothelium, while at the cardiomyocyte level Exendin-4 treatment alone was the most effective.
UV-Excited Fluorescence on Riparian Insects except Hymenoptera Is Associated with Nitrogen Content
Authors: Wiesenborn William D.
Published: June 2011

I photographed ultraviolet-excited fluorescence of external resilin on insects in 7 orders, 17 families, and 18 genera collected from shrubs and trees alongside the Colorado River in western Arizona, USA. The localized blue-fluorescence characteristic of resilin was emitted by a variety of structures including sutures and wing articulations on Odonata and Diptera and membranous wings, compound eyes, or ocelli on Hemiptera, Neuroptera, and Hymenoptera. Different widespread, but blotchy, light-blue fluorescence was observed on cuticles of immature Orthoptera and adult Hemiptera. Insects in Hymenoptera and Coleoptera fluoresced least. Ranked amounts of fluorescence, relative to body area, were positively correlated with ranked nitrogen contents (%N of body dry-mass) of insects in genera excluding Hymenoptera. Nitrogen concentrations in insect exoskeletons appear to increase as abundances of resilin and other fluorescent, elastic proteins increase. These structural compounds may be an important nitrogen source for insectivorous vertebrates.