bluuebunny/crossref_metadata_2025 huggingface dataset:
Blood pressure and the contractility of a human leg muscle
Authors: Luu Billy L. , Fitzpatrick Richard C.
Published: September 2013

Key points

At identical activation, muscle force production in a small, non‐postural hand muscle that normally operates near heart level is sensitive to physiological changes in perfusion pressure.

Here we investigate how perfusion pressure affects muscle contractility in a large leg muscle that is subject to high hydrostatic pressures in its normal role.

We show that this large postural muscle and the small hand muscle have similar perfusion–contractility relationships, and that changes in local perfusion and systemic blood pressure produce proportionately the same effects on muscle contractility.

The rapid and reversible modulation of contractility by perfusion pressure may be explained by interstitial [K+] that depends on the balance between energy‐dependent processes in the myocyte and passive vascular removal.

These results help explain how blood pressure is controlled through the pressor response during exercise and how muscle force production and fatigue varies in different postures.

Abstract  These studies investigate the relationships between perfusion pressure, force output and pressor responses for the contracting human tibialis anterior muscle. Eight healthy adults were studied. Changing the height of tibialis anterior relative to the heart was used to control local perfusion pressure. Electrically stimulated tetanic force output was highly sensitive to physiological variations in perfusion pressure showing a proportionate change in force output of 6.5% per 10 mmHg. This perfusion‐dependent change in contractility begins within seconds and is reversible with a 53 s time constant, demonstrating a steady‐state equilibrium between contractility and perfusion pressure. These stimulated contractions did not produce significant cardiovascular responses, indicating that the muscle pressor response does not play a major role in cardiovascular regulation at these workloads. Voluntary contractions at forces that would require constant motor drive if perfusion pressure had remained constant generated a central pressor response when perfusion pressure was lowered. This is consistent with a larger cortical drive being required to compensate for the lost contractility with lower perfusion pressure. The relationship between contractility and perfusion for this large postural muscle was not different from that of a small hand muscle (adductor pollicis) and it responded similarly to passive peripheral and active central changes in arterial pressure, but extended over a wider operating range of pressures. If we consider that, in a goal‐oriented motor task, muscle contractility determines central motor output and the central pressor response, these results indicate that muscle would fatigue twice as fast without a pressor response. From its extent, timing and reversibility we propose a testable hypothesis that this change in contractility arises through contraction‐ and perfusion‐dependent changes in interstitial K+ concentration.
Pharmacodynamic Target Attainment for Various Ceftazidime Dosing Schemes in High-Flux Hemodialysis
Authors: Loo Angela S. , Neely Michael , Anderson Evan J. , Ghossein Cybele , McLaughlin Milena M. , Scheetz Marc H.
Published: September 2013

Ceftazidime is a broad-spectrum cephalosporin with high-level activity against a variety of Gram-negative pathogens, including
Pseudomonas aeruginosa
. Improved outcomes are associated with cumulative percentages of a 24-h period that the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (%
T
MIC
) of >45 to 70% of the dosing interval. Optimal dosing to achieve a 90% probability of target attainment (PTA) in patients receiving high-flux hemodialysis (HFHD) is unknown. We used existing data from six anephric adults receiving hemodialysis to construct a population model with the Pmetrics package for R. From the final model's joint probability density, we simulated the PTA for various ceftazidime dosing regimens, HFHD schedules, and organism MICs. For HFHD every 48 h and 1 g of ceftazidime given posthemodialysis, the PTA exceeds 90% for all isolates with MICs of ≤8 μg/ml, assuming a goal of 70%
T
MIC
. For 72-h dialysis intervals, postdialysis dosing of 1 g is adequate for achievement of the 70%
T
MIC
goal only for organisms with MICs of ≤4 μg/ml, while 2 g is adequate for organisms with MICs of ≤8 μg/ml. A dose of 500 mg once daily, regardless of HFHD schedule, has a 90% PTA for organisms with MICs of ≤16 μg/ml, while 1 g once daily may achieve 100% PTA even for resistant organisms with a MIC of 32 μg/ml. Therefore, to ensure maximal ceftazidime activity, once-daily dosing of 500 mg to 1 g ceftazidime in patients receiving HFHD may be preferable for critically ill patients when MIC data are unavailable and for more resistant organisms with ceftazidime MICs of 16 to 32 μg/ml.
Rapid Viral Expansion and Short Drug Half-Life Explain the Incomplete Effectiveness of Current Herpes Simplex Virus 2-Directed Antiviral Agents
Authors: Schiffer Joshua T. , Swan David A. , Corey Lawrence , Wald Anna
Published: September 2013

The nucleoside analogues acyclovir (ACV) and famciclovir (FCV) reduce the frequency and severity of herpes simplex virus 2 (HSV-2) genital shedding, yet despite their high potency
in vitro
and a lack of induced drug resistance, frequent episodes of breakthrough mucosal shedding occur. We tested a published stochastic, spatial mathematical model of HSV-2 replication and spread, in concert with pharmacokinetic and pharmacodynamic equations, against virologic data from clinical trials of twice-daily acyclovir and famciclovir suppression. The model reproduced the key features of clinical trial data, including genital shedding episode rate, expansion and decay dynamics, and heterogeneous peak viral production and duration. In simulations, these agents shortened episode duration by limiting the extent of viral production by 1 to 2 log units and limiting the formation of secondary ulcers by ∼50%. However, drug concentrations were noninhibitory during 42% of the dosing cycle. Even if drug concentrations were high at episode initiation, prolonged episodes often ensued due to drug decay over ensuing hours and subsequent rebound of rapidly replicating HSV-2. The local CD8
+
T-cell density was more predictive of episode viral production (
R
2
= 0.42) and duration (
R
2
= 0.21) than the drug concentration at episode onset (
R
2
= 0.14 and 0.05, respectively), though the model projected that an agent with an equivalent potency but a two times longer half-life would decrease shedding by 80% compared to that of standard twice-daily regimens. Therefore, long half-life is a key characteristic of any agent that might fully suppress HSV-2 reactivations.
Ciprofloxacin Treatment Failure in a Murine Model of Pyelonephritis Due to an AAC(6′)-Ib-cr-Producing Escherichia coli Strain Susceptible to Ciprofloxacin
In Vitro
Authors: Guillard T. , Cambau E. , Chau F. , Massias L. , de Champs C. , Fantin B.
Published: September 2013

AAC(6′)-Ib-cr is a plasmid-mediated quinolone resistance mechanism described worldwide for
Escherichia coli
. Since it confers
in vitro
only a low level of resistance to ciprofloxacin, we evaluated its impact on the
in vivo
activity of ciprofloxacin. Isogenic strains were obtained by transferring plasmid p449, harboring
aac(6
′
)-Ib-cr
, into the quinolone-susceptible strain
E. coli
CFT073-RR and its D87G
gyrA
mutant. MICs were 0.015, 0.06, 0.25, and 0.5 μg/ml against
E. coli
strains CFT073-RR, CFT073-RR/p449, CFT073-RR GyrA
r
, and CFT073-RR GyrA
r
/p449, respectively. Bactericidal activity was reduced at 1× the MIC for the three resistant derivatives, while at a fixed concentration of 0.5 μg/ml, 99.9% killing was observed for all strains except
E. coli
CFT073-RR GyrA
r
/p449. In the murine model of pyelonephritis, an optimal regimen of ciprofloxacin (10 mg/kg of body weight twice a day [b.i.d.]) significantly decreased the bacterial count in the kidneys of mice infected with
E. coli
CFT073 (1.6 versus 4.3 log
10
CFU/g of kidney compared to untreated controls;
P
= 0.0001), while no significant decrease was observed for
E. coli
CFT073-RR/p449 (2.7 versus 3.1 log
10
CFU/g;
P
= 0.84),
E. coli
CFT073-RR GyrA
r
(4.2 versus 4.1 log
10
CFU/g;
P
= 0.35), or
E. coli
CFT073-RR GyrA
r
/p449 (2.9 versus 3.6 log
10
CFU/g;
P
= 0.47). While pharmacokinetic and pharmacodynamic (PK/PD) parameters accounted for ciprofloxacin failure against
gyrA
-containing mutants, this was not the case for the
aac(6
′
)-Ib-cr
-containing strains, suggesting an
in situ
hydrolysis of ciprofloxacin in the latter case.
Interlaboratory Variability of Caspofungin MICs for Candida spp. Using CLSI and EUCAST Methods: Should the Clinical Laboratory Be Testing This Agent?
Authors: Espinel-Ingroff A. , Arendrup M. C. , Pfaller M. A. , Bonfietti L. X. , Bustamante B. , Canton E. , Chryssanthou E. , Cuenca-Estrella M. , Dannaoui E. , Fothergill A. , Fuller J. , Gaustad P. , Gonzalez G. M. , Guarro J. , Lass-Flörl C. , Lockhart S. R. , Meis J. F. , Moore C. B. , Ostrosky-Zeichner L. , Pelaez T. , Pukinskas S. R. B. S. , St-Germain G. , Szeszs M. W. , Turnidge J.
Published: September 2013

Although Clinical and Laboratory Standards Institute (CLSI) clinical breakpoints (CBPs) are available for interpreting echinocandin MICs forCandidaspp., epidemiologic cutoff values (ECVs) based on collective MIC data from multiple laboratories have not been defined. While collating CLSI caspofungin MICs for 145 to 11,550Candidaisolates from 17 laboratories (Brazil, Canada, Europe, Mexico, Peru, and the United States), we observed an extraordinary amount of modal variability (wide ranges) among laboratories as well as truncated and bimodal MIC distributions. The species-specific modes across different laboratories ranged from 0.016 to 0.5 μg/ml forC. albicansandC. tropicalis, 0.031 to 0.5 μg/ml forC. glabrata, and 0.063 to 1 μg/ml forC. krusei. Variability was also similar among MIC distributions forC. dubliniensisandC. lusitaniae. The exceptions wereC. parapsilosisandC. guilliermondiiMIC distributions, where most modes were within one 2-fold dilution of each other. These findings were consistent with available data from the European Committee on Antimicrobial Susceptibility Testing (EUCAST) (403 to 2,556 MICs) forC. albicans,C. glabrata,C. krusei, andC. tropicalis. Although many factors (caspofungin powder source, stock solution solvent, powder storage time length and temperature, and MIC determination testing parameters) were examined as a potential cause of such unprecedented variability, a single specific cause was not identified. Therefore, it seems highly likely that the use of the CLSI species-specific caspofungin CBPs could lead to reporting an excessive number of wild-type (WT) isolates (e.g.,C. glabrataandC. krusei) as either non-WT or resistant isolates. Until this problem is resolved, routine testing or reporting of CLSI caspofungin MICs forCandidais not recommended; micafungin or anidulafungin data could be used instead.
Characterization and Identification of a Novel Candidate Vaccine Protein through Systematic Analysis of Extracellular Proteins of Erysipelothrix rhusiopathiae
Authors: Shi Fang , Ogawa Yohsuke , Sano Akiyuki , Harada Tomoyuki , Hirota Jiro , Eguchi Masahiro , Oishi Eiji , Shimoji Yoshihiro
Published: September 2013

Erysipelothrix rhusiopathiae
, the causative agent of swine erysipelas, is a facultative intracellular Gram-positive bacterium. It has been shown that animals immunized with a filtrate from
E. rhusiopathiae
cultures are protected against lethal challenge. In this study, we identified and characterized the extracellular proteins of
E. rhusiopathiae
to search for novel vaccine antigens. A concentrated culture supernatant from the
E. rhusiopathiae
Fujisawa strain, which has been found to induce protection in mice, was analyzed using two-dimensional electrophoresis. From more than 40 confirmed protein spots, 16 major protein spots were selected and subjected to N-terminal amino acid sequence determination, and 14 protein spots were successfully identified. The identified proteins included housekeeping proteins and other metabolic enzymes. We searched for surface-localized proteins by analyzing the genomes of two
E. rhusiopathiae
strains: Fujisawa and ATCC 19414. Genome analysis revealed that the ATCC 19414 strain has three putative surface-exposed
c
holine-
b
inding
p
roteins (CBPs): CbpA, CbpB, and CbpC. Each CBP contains a putative choline-binding domain. The CbpC gene is mutated in Fujisawa, becoming a nonfunctional pseudogene. Immunogold electron microscopy confirmed that CbpA and CbpB, as well as the majority of the metabolic enzymes examined, are associated with the cell surface of
E. rhusiopathiae
Fujisawa. Immunization with recombinant CbpB, but not with other recombinant CBPs or metabolic enzymes, protected mice against lethal challenge. A phagocytosis assay revealed that antiserum against CbpB promoted opsonin-mediated phagocytosis by murine macrophages
in vitro
. The protective capabilities of CbpB were confirmed in pigs, suggesting that CbpB could be used as a vaccine antigen.
Culture and behaviour in the English National Health Service: overview of lessons from a large multimethod study
Authors: Dixon-Woods Mary , Baker Richard , Charles Kathryn , Dawson Jeremy , Jerzembek Gabi , Martin Graham , McCarthy Imelda , McKee Lorna , Minion Joel , Ozieranski Piotr , Willars Janet , Wilkie Patricia , West Michael
Published: September 2013

Background

Problems of quality and safety persist in health systems worldwide. We conducted a large research programme to examine culture and behaviour in the English National Health Service (NHS).

Methods

Mixed-methods study involving collection and triangulation of data from multiple sources, including interviews, surveys, ethnographic case studies, board minutes and publicly available datasets. We narratively synthesised data across the studies to produce a holistic picture and in this paper present a high-level summary.

Results

We found an almost universal desire to provide the best quality of care. We identified many ‘bright spots’ of excellent caring and practice and high-quality innovation across the NHS, but also considerable inconsistency. Consistent achievement of high-quality care was challenged by unclear goals, overlapping priorities that distracted attention, and compliance-oriented bureaucratised management. The institutional and regulatory environment was populated by multiple external bodies serving different but overlapping functions. Some organisations found it difficult to obtain valid insights into the quality of the care they provided. Poor organisational and information systems sometimes left staff struggling to deliver care effectively and disempowered them from initiating improvement. Good staff support and management were also highly variable, though they were fundamental to culture and were directly related to patient experience, safety and quality of care.

Conclusions

Our results highlight the importance of clear, challenging goals for high-quality care. Organisations need to put the patient at the centre of all they do, get smart intelligence, focus on improving organisational systems, and nurture caring cultures by ensuring that staff feel valued, respected, engaged and supported.
Mechanical endovascular procedure for the treatment of acute ischemic stroke caused by total detachment of a papillary fibroelastoma
Authors: Tejada Javier , Galiana Alberto , Balboa Óscar , Clavera Belén , Redondo-Robles Laura , Alonso Nieves , Magadán Víctor
Published: September 2013

Papillary fibroelastomas (PFEs) are rare cardiac tumors. Despite their benign nature, they are associated with a high risk of embolic complications including stroke. Endovascular treatment has been reported as a safe procedure in patients with myxoma, the most common type of primary cardiac tumor. A case of ischemic stroke due to embolization of a PFE successfully treated with a single pass of a retrievable stent is described. A 64-year-old patient with a right middle cerebral artery syndrome was treated with an intravenous and endovascular protocol as a revascularization procedure. Mechanical thrombectomy resulted in total recanalization with clinical improvement. Histological examination of the clot showed pathological features of a typical PFE. The endovascular treatment was safe and effective. With mechanical embolectomy it is possible to obtain and analyze pathological specimens, enabling the diagnosis of uncommon strokes.
Carotid artery stenting without post-stenting balloon dilatation
Authors: Ogata Atsushi , Sonobe Makoto , Kato Noriyuki , Yamazaki Tomosato , Kasuya Hiromichi , Ikeda Go , Miki Shunichiro , Matsushima Toshio
Published: September 2013

Purpose

To evaluate the clinical outcome and MRI findings after carotid artery stenting (CAS) without post-dilatation.

Methods

Between May 2005 and April 2012, a total of 169 consecutive patients (61.4% symptomatic) underwent 176 CAS procedures performed with an embolic protection device (GuardWire, n=116; FilterWire EZ, n=60). All stents were deployed without post-dilatation. Periprocedural complications and mid-term outcomes were analyzed.

Results

The stroke rate was 2.3% within 30 days post-CAS (asymptomatic patients 1.5%; symptomatic patients 2.8%). Cerebral infarction occurred in one asymptomatic patient (1.5%) and one symptomatic patient (0.9%). Intracranial hemorrhage occurred in two symptomatic patients (1.9%). Post-CAS diffusion-weighted imaging (DWI) revealed a high-intensity area in 26 of 176 procedures (14.8%). Ipsilateral stroke after 31 days occurred in two patients (1.1%) and restenosis occurred in six (3.4%). A post-CAS comparison of the embolic protection devices revealed no difference in stroke incidence within 30 days and in DWI high-intensity area.

Conclusions

Our CAS procedure without post-dilatation is feasible, safe and associated with a low incidence of stroke and restenosis.
Flexible tip guides and intermediate catheters: two center experience and a proposed taxonomy
Authors: Hui Ferdinand K , Schuette A Jesse , Spiotta Alejandro M , Yim John , Obuchowski Nancy , Rasmussen Peter A , Hussain Mohammed Shazam , Cawley C Michael , Dion Jacques E , Tong Frank C
Published: September 2013

Background

Stable access to target lesions is foundational to endovascular therapy, be it in hemorrhagic or ischemic disease. Continued evolution in access technology has resulted in next generation catheters that afford improved trackability and proximal support.

Objective

Assess safety and patterns of use at two high volume centers, and conceptualize usage patterns.

Materials and methods

A retrospective review of 608 cases in which a ‘next generation’ catheter was used during 2008–2010 at Cleveland Clinic (Cleveland, Ohio, USA) and throughout 2009–2010 at Emory University Hospital (Atlanta, Georgia, USA) was conducted, and the cases classified by indication. Catheter placement, distal most location, and related complications were recorded and experience summarized. We also reviewed the differences in the catheters and the rationale for catheter selection, as well as relative costs for each approach.

Results

311 Neuron 053, 166 Neuron 070, 36 distal access catheter (DAC) 3.9 F, 61 DAC 4.3 F, and 34 DAC 5.2 F catheters were deployed. Of these, 459 placements were in the anterior circulation, 130 in the posterior circulation, 11 in the external carotid artery, and eight were used intravenously. Complication rates were 9/131 (6.9%) for the DAC catheter group, 16/311 (5.1%) for the Neuron 053 group, and 14/166 (8.4%) for the Neuron 070 group (p=0.37, χ2test).

Conclusions

Next generation access catheters possess characteristics that blend qualities of traditional microcatheters and stiff guide catheters. There was no statistically significant difference in complication rates between the various catheter families in this small retrospective review, and the complication rates were similar to historical complication rates.
A study of the conformational profile and the vibrational spectra of the plant hormone indole-3-acetic acid
Authors: Förner Wolfgang , Badawi Hassan M.
Published: September 2013

The structural stability of indole-3-acetic acid was investigated by DFT-B3LYP calculations with the 6-311G** basis set. From the calculations the gauche–gauche (gg) structure was predicted to be the second lowest energy minimum for the acid. It is energetically only 0.57 kcal/mol above the lowest conformer which is the trans–cis (tc) structure. A further stable conformer, however, highest in energy, is the trans–trans (tt) one, which is by 2.68 kcal/mol higher in energy than tc. The tc conformer upon full optimization turned a little bit away from real tc to a near tc (ntc) structure (defining torsional angles only changed by a few decigrades). However, the X-ray data indicate a structure in the solid, which is most similar to gg, stabilized by intermolecular eight ring hydrogen bonds. In the present DFT calculations such stabilizations cannot be accounted for, because the calculations treat only isolated molecules. To take such interactions into account at least dimers would have to be optimized. Therefore the vibrational frequencies of the gg conformer were computed at the B3LYP level of theory and tentative vibrational assignments were provided on the basis of normal coordinate analysis, normal mode calculations and experimental infrared and Raman data. However, some of the observed lines are obviously due to a small amount of the tc conformer present.
Electrochemical and spectroelectrochemical studies of β-phosphorylated Zn porphyrins
Authors: Fang Yuanyuan , Kadish Karl M. , Chen Ping , Gorbunova Yulia , Enakieva Yulia , Tsivadze Aslan , Bessmertnykh-Lemeune Alla , Guilard Roger
Published: September 2013

The electrochemical and spectroelectrochemical properties of two β-phosphorylated Zn porphyrins, [2-diethoxyphosphoryl-5,10,15,20-tetraphenylporphyrinato]zinc (1) and [2-diisopropoxyphosphoryl-5,10,15,20-tetraphenylporphyrinato]zinc (2), are reported in CH 2 Cl 2 and PhCN containing tetrabutylammonium perchlorate (TBAP) or tetrabutylammonium hexafluorophosphate (TBAPF6) as supporting electrolyte. Under certain solution conditions, three one-electron reductions are observed, with the last process being attributed to the product of a chemical reaction following formation of the porphyrin dianion. Two or three oxidations are observed for the same compounds, again depending upon the solution conditions. In some cases, two well-defined and well-separated one electron oxidations are observed but in others the first one-electron abstraction to give the porphyrin radical cation is split into two redox processes, separated from each other by 110–140 mV. This splitting of the first oxidation into two processes is attributed to linking of the two porphyrins which results when a P = O unit of the phosphoryl substituent on one porphyrin binds to the Zn ( II ) center of a second porphyrin, resulting in dimer formation. The interaction between the two macrocycles is discussed in terms of the difference in potentials between the two split redox processes (ΔE1/2) and the overall data is compared with that for other porphyrin dimers and bis-macrocycles reported in the literature.
IMPLEMENTATION OF ENVIRONMENTAL IMPACT ASSESSMENT IN CHINA
Authors: REN XIN
Published: September 2013

The paper describes major developments of environmental impact assessment (EIA) in China since 2003 when its EIA law became effective, with emphasis on those aspects not sufficiently touched upon by most researchers so far. These range from threshold-based categorization, evolution in scoping, expansion and upgrading of a series of technical guidelines for EIA, addition of water and soil conservation plan to EIA, public consultation and social impact assessment to interaction with other major means of environmental management in China (i.e. total pollution load control, discharge permit and cleaner production). Based on a literature review, exchanges with EIA practitioners and the author's daily work on EIA, it is found that EIA in China has evolved into a fairly comprehensive and technically adequate system. The biggest problem lies in its poor enforcement and implementation, which is the focus of this paper. By examining each practical step in reviewing, enforcing and implementing EIA, the paper evaluates EIA's role in optimizing decision-making (e.g. by alternative analysis), EIA implementation and its supervision piloted in China, underlying technical, procedural and institutional issues and concerns, and the disconnect between project EIA and plan/regional EIA, both with regards to theory and practice. The main reasons for weak EIA enforcement and implementation are discussed, which include the political system and incentive mechanisms, institutional arrangements, and regulatory and methodological shortcomings. Based on the analysis, recommendations are made for improving enforcement and implementation of EIA in China.
COMMUNITY-BASED FLOOD VULNERABILITY AND ADAPTATION ASSESSMENT: A CASE STUDY FROM BANGLADESH
Authors: YOUNUS MD ABOUL FAZAL , HARVEY NICK
Published: September 2013

The Intergovernmental Panel on Climate Change (IPCC) (2007, 2012:11) warned that the mega deltas in South Asia (e.g. the Ganges Brahmaputra Meghna River Basin) will be at great risk due to increased flooding, and the region's poverty would reduce the capacity of the inhabitants to adapt to change. This paper provides a "bottom up" impact approach which focuses on a methodological contribution for assessment of vulnerability and adaptation (V & A) in a riverine flood-prone area, "Islampur" in Bangladesh, where various impact assessment guidelines have been taken into consideration. In this study the evaluation of V & A assessments at community level has been accomplished mainly by a weighted matrix index value derived from two participatory rapid appraisals (PRAs). Based on the distribution pattern of various weighted value indices of V & A issues, the required adaptation techniques can be adopted for immediate policy-making, and appropriate actions should be undertaken through establishing community-based adaptation committees (CBAC).
The emergence of the Eoarchaean proto-arc: evolution of a
c.
3700 Ma convergent plate boundary at Isua, southern West Greenland
Authors: Nutman Allen P. , Bennett Vickie C. , Friend Clark R. L.
Published: September 2013

Eoarchaean juvenile crust formed as ‘proto-arcs’. The northern side of the Isua supracrustal belt is an archetypal proto-arc, with ≥3720 Ma boninites,
c.
3720 Ma basalts and gabbros, 3720–3710 Ma andesites, diorites and mafic tonalites, 3710–3700 Ma intermediate-felsic volcanic and sedimentary rocks and 3700–3690 Ma chemical sedimentary rocks. On its northern side there is an extensive body of 3700–3690 Ma tonalite. During its evolution, the
c.
3700 Ma Isua volcanic–sedimentary assemblage was partitioned into tectonic slices, with intercalation of mantle dunites with pillow basalts, prior to intrusion of
c.
3710 Ma quartz diorites. Partitioning also occurred at 3690–3660 Ma, when the 30–20 million years life of the
c.
3700 Ma Isua proto-arc was terminated by juxtaposition with the
c.
3800 Ma terrane that occurs along the south of the Isua supracrustal belt. The trace element chemistry for all the ≥3720–3700 Ma mafic to intermediate volcanic rocks indicates fluid-fluxing mantle melting. The
c.
3690 Ma tonalites have signatures showing melting of garnet-bearing mafic (eclogite) sources. The Isua
c.
3700 Ma assemblage developed at an intra-oceanic convergent plate boundary, and it has a life-cycle broadly analogous to (but not identical to) an oceanic island arc eventually accreted against older crust.
A Hf-isotope perspective on continent formation in the south Peruvian Andes
Authors: Boekhout Flora , Roberts Nick M. W. , Gerdes Axel , Schaltegger Urs
Published: September 2013

Convergent continental margins are the primary host of both growth and loss of continental crust. Continental growth largely occurs via subduction-driven magmatism, whereas continental loss largely occurs via subduction erosion and sediment subduction. Because the latter typically involves partial recycling into magmas, both growth and loss of continental crust can be represented in the magmatic record. The degree of crustal recycling can be estimated from the initial Hf isotope signatures in both magmatic and detrital zircon grains. Recent insights into the geodynamic evolution of the Peruvian margin, in combination with a new dataset of Hf isotopic data on zircon from the Carboniferous to Early Cretaceous, enable us to (1) compare the geodynamic history of the southern Peruvian margin with its Hf isotopic evolution, and (2) quantify the crustal growth between 500 and 135 Ma. The data exhibit a correlation with trends in isotope composition v. time and reflect the dominantly extensional regime that prevailed from the onset of subduction from 530 Ma to
c.
135 Ma. This study demonstrates that the Peruvian margin experienced continental growth with juvenile input to arc magmatism of 30–45% on average, and illustrates the use of U–Pb and Hf isotopes in zircon as a tool to trace episodes of crustal growth through time.

Supplementary material:

Hf istopic analyses on zircon (A1 and A2) and new U–Pb zircon ages (A3) are available at
http://www.geolsoc.org.uk/SUP18661
.
Higher levels of intrinsic motivation are related to higher levels of class performance for male but not female students
Authors: Cortright Ronald N. , Lujan Heidi L. , Blumberg Amanda J. , Cox Julie H. , DiCarlo Stephen E.
Published: September 2013

Our students are naturally curious, with powerful intrinsic motives to understand their world. Accordingly, we, as teachers, must capitalize on this inherently active and curious nature so that learning becomes a lifelong activity where students take initiative for learning, are skilled in learning, and want to learn new things. Achieving this goal requires an understanding of student attitudes, beliefs, characteristics, and motivations. To achieve this goal, we administered the intrinsic motivation inventory (IMI) to assess our students' interest and enjoyment, perceived choice, and perceived competence while taking our undergraduate exercise physiology class (46 students; 20 female students and 26 male students). The interest and enjoyment subscale is considered the self-reported measure of intrinsic motivation. The perceived choice and perceived competence concepts are theorized to be positive predictors of both self-reported and behavioral measures of intrinsic motivation. Our results documented a significant increase in course grade with an increase in survey score for the interest and enjoyment subscale of the IMI when female and male students were combined. Specifically, each increase in survey score for the interest and enjoyment subscale of the IMI was associated with a significant ( P < 0.05) increase of 3.9% in course grade. However, the increase in survey score was associated with a significantly greater ( P < 0.05) increase in course grade for male (6.1%) compared with female (0.3%) students. These results have implications for both classroom practice and educational reform policies.
Evaluating learning among undergraduate medical students in schools with traditional and problem-based curricula
Authors: Meo Sultan Ayoub
Published: September 2013

This study aimed to assess knowledge and skills in a respiratory physiology course in traditional versus problem-based learning (PBL) groups in two different medical schools. Two different undergraduate medical schools were selected for this study. The first medical school followed the traditional [lecture-based learning (LBL)] curriculum, and the second medical school followed the PBL curriculum. Sixty first-year male medical students (30 students from each medical school) volunteered; they were apparently healthy and of the same age, sex, nationality, and regional and cultural background. Students were taught respiratory physiology according to their curriculum for a period of 2 wk. At the completion of the study period, knowledge was measured based on a single best multiple-choice question examination, and skill was measured based on the objective structured practical examination in the lung function laboratory (respiratory physiology). A Student's t-test was applied for the analysis of the data, and the level of significance was set at P < 0.05. Students belonging to the PBL curriculum obtained a higher score in the multiple-choice question examination ( P = 0.001) and objective structured practical examination ( P = 0.0001) compared with traditional (LBL) students. Students in the PBL group obtained significantly higher knowledge and skill scores in the respiratory physiology course compared with students in the traditional (LBL) style of medical schools.
Process-oriented guided-inquiry learning improves long-term retention of information
Authors: Vanags Thea , Pammer Kristen , Brinker Jay
Published: September 2013

Many chemistry educators have adopted the process-oriented guided instructional learning (POGIL) pedagogy. However, it is not clear which aspects of POGIL are the most important in terms of actual learning. We compared 354 first-year undergraduate psychology students' learning in physiological psychology using four teaching methods: control, POGIL, POGIL without reporting [no report out (NRO)], and POGIL run by untrained graduate students [new facilitator (NF)]. Student activities were identical across POGIL variations and highly similar for control. Participants' knowledge was evaluated before (pretest), immediately after (posttest), and 2 wk later (followup). Control and POGIL groups showed no improvement at posttest, whereas NRO and NF groups both recalled more material than at pretest ( P = 0.002 and P < 0.0005, respectively). In a surprise test 2 wk later, control ( P < 0.0005), NRO ( P = 0.03), and NF ( P < 0.0005) groups recalled less than at posttest. The POGIL group showed the smallest drop in knowledge ( P = 0.05). Importantly, the control group's knowledge was below pretest levels ( P < 0.0005), whereas the POGIL, NRO, and NF groups' knowledge was not. Self-assessment of knowledge was consistent across groups at pretest, but POGIL participants had the lowest confidence at posttest and 2 wk later. At followup, the control, NRO, and NF groups showed greater confidence in their knowledge than the POGIL group ( P = 0.03, P = 0.002, and P = 0.004, respectively). POGIL and its variations appear to consolidate existing knowledge against memory decay even when student confidence does not match performance.
Nonlocal Nonlinear Optical Response of Ionic Liquids under Violet Excitation
Authors: Santos Cássio E. A. , Alencar Márcio A. R. C. , Migowski Pedro , Dupont Jairton , Hickmann Jandir M.
Published: September 2013

The nonlocal nonlinearity under violet excitation of ionic liquids was investigated using the Z-scan technique. The bis(trifluoromethylsulfonyl)imide (Tf2N−) was employed as anionic part, while the cationic part consisted of four different imidazolium (, with , 6, 8, and 10) derivatives. The thermooptical coefficients, nonlinear refractive indexes of thermal origin, and degree of nonlocality were obtained for laser excitation tuned at 410 nm. Our results indicate that ionic liquids can be exploited as very efficient nonlinear media with large nonlocal character under violet excitation.
MicroRNAs in Kidney Fibrosis and Diabetic Nephropathy: Roles on EMT and EndMT
Authors: Srivastava Swayam Prakash , Koya Daisuke , Kanasaki Keizo
Published: September 2013

MicroRNAs (miRNAs) are a family of small, noncoding RNAs that regulate gene expression in diverse biological and pathological processes, including cell proliferation, differentiation, apoptosis, and carcinogenesis. As a result, miRNAs emerged as major area of biomedical research with relevance to kidney fibrosis. Fibrosis is characterized by the excess deposition of extracellular matrix (ECM) components, which is the end result of an imbalance of metabolism of the ECM molecule. Recent evidence suggests that miRNAs participate in the fibrotic process in a number of organs including the heart, kidney, liver, and lung. Epithelial mesenchymal transition (EMT) and endothelial mesenchymal transition (EndMT) programs play vital roles in the development of fibrosis in the kidney. A growing number of the extracellular and intracellular molecules that control EMT and EndMT have been identified and could be exploited in developing therapeutics for fibrosis. This review highlights recent advances on the role of miRNAs in the kidney diseases; diabetic nephropathy especially focused on EMT and EndMT program responsible for the development of kidney fibrosis. These miRNAs can be utilized as a potential novel drug target for the studying of underlying mechanism and treatment of kidney fibrosis.
Performance Analysis of Flat and Rippled Wick-Inverted V-Type Solar Still Integrated with Drip System in Kerala Climatic Conditions
Authors: Namshad T. , Ayush K. R. , Salih K. C. , James Athul , Ahammed Suficker , Vayalilakath Hashim , Suneesh P. U.
Published: September 2013

Thermal aspect of solar energy is widely used in the desalination plants. Experimental investigation and mathematical modeling of inverted V-type solar still integrated with drip system are presented in this paper. The experiment is performed in the Kerala climatic conditions (10.8439°N, 76.0328°E), March 2012 at M E S College of Engineering, Kuttippuram. A two segment still of 2 m2 is constructed. Experimental investigations on productivity and internal heat transfer are analyzed. The results indicate that the mean standard deviations between theoretical and experimental values are less than 7% (temperature of rippled wick), 8% (temperature of glass in rippled system), 11% (temperature of flat wick), and 7% (temperature of glass in flat system), an average for the working hours of the day.
Catalpol Induces Neuroprotection and Prevents Memory Dysfunction through the Cholinergic System and BDNF
Authors: Wan Dong , Xue LiJun , Zhu HuiFeng , Luo Yong
Published: September 2013

To investigate the role and mechanism of catalpol on neuroprotective effects and memory enhancing effects simultaneously, neuroprotective effects of catalpol were assessed by neurological deficits score, TTC staining, and cerebral blood flow detecting. Morris water maze was employed to investigate its effects on learning and memory and then clarify its possible mechanisms relating the central cholinergic system and BDNF. Edaravone and oxiracetam were used for positive control drugs based on its different action. Results showed that catalpol and edaravone significantly facilitated neurological function recovery, reduced infarction volume, and increased cerebral blood flow in stroke mice. Catalpol and oxiracetam decreased the escape latency significantly and increased the numbers of crossing platform obviously. The levels of ACh, ChAT, and BDNF in catalpol group were increased in a dose-dependent manner, and AChE declined with a U-shaped dose-response curve. Moreover, the levels of muscarinic AChR subtypes M1and M2in hippocampus were considerably raised by catalpol. These results demonstrated that catalpol may be useful for neuroprotection and memory enhancement, and the mechanism may be related to the central cholinergic system.
Soluble Form of Canine Transferrin Receptor Inhibits Canine Parvovirus InfectionIn VitroandIn Vivo
Authors: Wen Jiexia , Pan Sumin , Liang Shuang , Zhong Zhenyu , He Ying , Lin Hongyu , Li Wenyan , Wang Liyue , Li Xiujin , Zhong Fei
Published: September 2013

Canine parvovirus (CPV) disease is an acute, highly infectious disease threatening the dog-raising industry. So far there are no effective therapeutic strategies to control this disease. Although the canine transferrin receptor (TfR) was identified as a receptor for CPV infection, whether extracellular domain of TfR (called soluble TfR (sTfR)) possesses anti-CPV activities remains elusive. Here, we used the recombinant sTfR prepared from HEK293T cells with codon-optimized gene structure to investigate its anti-CPV activity bothin vitroandin vivo. Our results indicated that codon optimization could significantly improve sTfR expression in HEK293T cells. The prepared recombinant sTfR possessed a binding activity to both CPV and CPV VP2 capsid proteins and significantly inhibited CPV infection of cultured feline F81 cells and decreased the mortality of CPV-infected dogs, which indicates that the sTfR has the anti-CPV activity bothin vitroandin vivo.
Nanostructural Features of Silver Nanoparticles Powder Synthesized through Concurrent Formation of the Nanosized Particles of Both Starch and Silver
Authors: Hebeish A. , El-Rafie M. H. , El-Sheikh M. A. , El-Naggar Mehrez E.
Published: September 2013

Green innovative strategy was developed to accomplish silver nanoparticles formation of starch-silver nanoparticles (St-AgNPs) in the powder form. Thus, St-AgNPs were synthesized through concurrent formation of the nanosized particles of both starch and silver. The alkali dissolved starch acts as reducing agent for silver ions and as stabilizing agent for the formed AgNPs. The chemical reduction process occurred in water bath under high-speed homogenizer. After completion of the reaction, the colloidal solution of AgNPs coated with alkali dissolved starch was cooled and precipitated using ethanol. The powder precipitate was collected by centrifugation, then washed, and dried; St-AgNPs powder was characterized using state-of-the-art facilities including UV-vis spectroscopy, Transmission Electron Microscopy (TEM), particle size analyzer (PS), Polydispersity index (PdI), Zeta potential (ZP), XRD, FT-IR, EDX, and TGA. TEM and XRD indicate that the average size of pure AgNPs does not exceed 20 nm with spherical shape and high concentration of AgNPs (30000 ppm). The results obtained from TGA indicates that the higher thermal stability of starch coated AgNPS than that of starch nanoparticles alone. In addition to the data obtained from EDX which reveals the presence of AgNPs and the data obtained from particle size analyzer and zeta potential determination indicate that the good uniformity and the highly stability of St-AgNPs).
Cost-Effectiveness of Catheter Ablation for Rhythm Control of Atrial Fibrillation
Authors: Blackhouse Gord , Assasi Nazila , Xie Feng , Gaebel Kathryn , Campbell Kaitryn , Healey Jeff S. , O'Reilly Daria , Goeree Ron
Published: September 2013

Objective. The objective of this study is to evaluate the cost-effectiveness of catheter ablation for rhythm control compared to antiarrhythmic drug (AAD) therapy in patients with atrial fibrillation (AF) who have previously failed on an AAD.Methods. An economic model was developed to compare (1) catheter ablation and (2) AAD (amiodarone 200 mg/day). At the end of the initial 12 month phase of the model, patients are classified as being in normal sinus rhythm or with AF, based on data from a meta-analysis. In the 5-year Markov phase of the model, patients are at risk of ischemic stroke each 3-month model cycle.Results. The model estimated that, compared to the AAD strategy, ablation had $8,539 higher costs, 0.033 fewer strokes, and 0.144 more QALYS over the 5-year time horizon. The incremental cost per QALY of ablation compared to AAD was estimated to be $59,194. The probability of ablation being cost-effective for willingness to pay thresholds of $50,000 and $100,000 was estimated to be 0.89 and 0.90, respectively.Conclusion. Based on current evidence, pulmonary vein ablation for treatment of AF is cost-effective if decision makers willingness to pay for a QALY is $59,194 or higher.
Analytical Solution of Nonlinear Boundary Value Problem for Fin Efficiency of Convective Straight Fins with Temperature-Dependent Thermal Conductivity
Authors: Saravanakumar K. , Ananthaswamy V. , Subha M. , Rajendran L.
Published: September 2013

We have employed homotopy analysis method (HAM) to evaluate the approximate analytical solution of the nonlinear equation arising in the convective straight fins with temperature-dependent thermal conductivity problem. Solutions are presented for the dimensionless temperature distribution and fin efficiency of the nonlinear equation. The analytical results are compared with previous work and satisfactory agreement is noted.
Reporting Vaccine Complications: What Do Obstetricians and Gynecologists Know About the Vaccine Adverse Event Reporting System?
Authors: Eckert L. O. , Anderson B. L. , Gonik B. , Schulkin J.
Published: September 2013

Background. Obstetrician-gynecologists are increasingly called upon to be vaccinators as an essential part of a woman’s primary and preventive health care. Despite the established safety of vaccines, vaccine adverse events may occur. A national Vaccine Adverse Event Reporting System (VAERS) is a well-established mechanism to track adverse events. However, we hypothesized that many obstetrician-gynecologists are naive to the role and use of VAERS.Methods. We devised a ten-question survey to a sample of ACOG fellows to assess their knowledge and understanding of VAERS. We performed descriptive and frequency analysis for each of the questions and used one-way analysis of variance for continuous and chi-squared for categorical variables.Results. Of the 1000 fellows who received the survey, 377 responded. Only one respondent answered all nine knowledge questions correctly, and 9.2% of physicians had used VAERS. Older physicians were less familiar with VAERS in general and with the specific objectives of VAERS in particular (χ2=10.7,P=.005).Conclusions. Obstetrician-gynecologist familiarity with VAERS is lacking. Only when the obstetrician-gynecologist is completely knowledgeable regarding standard vaccine practices, including the availability and use of programs such as VAERS, will providers be functioning as competent and complete vaccinators.
Pharmacophore Modeling and Docking Studies on Some Nonpeptide-Based Caspase-3 Inhibitors
Authors: Sharma Simant , Basu Arijit , Agrawal R. K.
Published: September 2013

Neurodegenerative disorders are major consequences of excessive apoptosis caused by a proteolytic enzyme known as caspase-3. Therefore, caspase-3 inhibition has become a validated therapeutic approach for neurodegenerative disorders. We performed pharmacophore modeling on some synthetic derivatives of caspase-3 inhibitors (pyrrolo[3,4-c]quinoline-1,3-diones) using PHASE 3.0. This resulted in the common pharmacophore hypothesis AAHRR.6 which might be responsible for the biological activity: two aromatic rings (R) mainly in the quinoline nucleus, one hydrophobic (H) group (CH3), and two acceptor (A) groups (–C=O). After identifying a valid hypothesis, we also developed an atom-based 3D-QSAR model applying the PLS algorithm. The developed model was statistically robust (q2=0.53; pred_r2=0.80). Additionally, we have performed molecular docking studies, cross-validated our results, and gained a deeper insight into its molecular recognition process. Our developed model may serve as a query tool for future virtual screening and drug designing for this particular target.