bluuebunny/crossref_metadata_2025 huggingface dataset:
First Report of an OXA-48-Producing Multidrug-Resistant Proteus mirabilis Strain from Gaza, Palestine
Authors: Chen Liang , Al Laham Nahed , Chavda Kalyan D. , Mediavilla Jose R. , Jacobs Michael R. , Bonomo Robert A. , Kreiswirth Barry N.
Published: April 2015

We report the first multidrug-resistant
Proteus mirabilis
strain producing the carbapenemase OXA-48 (Pm-OXA-48) isolated at Al-Shifa hospital in Gaza, Palestine. Draft genome sequencing of Pm-OXA-48 identified 16 antimicrobial resistance genes, encoding resistance to β-lactams, aminoglycosides, fluoroquinolones, phenicols, streptothricin, tetracycline, and trimethoprim-sulfamethoxazole. Complete sequencing of the
bla
OXA-48
-harboring plasmid revealed that it is a 72 kb long IncL/M plasmid, harboring carbapenemase gene
bla
OXA-48
, extended spectrum β-lactamase gene
bla
CTX-M-14
, and aminoglycoside resistance genes
strA
,
strB
, and
aph(3
′
)-VIb
.
Melanin Protects Paracoccidioides brasiliensis from the Effects of Antimicrobial Photodynamic Inhibition and Antifungal Drugs
Authors: Baltazar Ludmila Matos , Werneck Silvia Maria Cordeiro , Soares Betânia Maria , Ferreira Marcus Vinicius L. , Souza Danielle G. , Pinotti Marcos , Santos Daniel Assis , Cisalpino Patrícia Silva
Published: April 2015

Paracoccidioidomycosis (PCM) is a public health concern in Latin America and South America that when not correctly treated can lead to patient death. In this study, the influence of melanin produced by
Paracoccidioides
spp. on the effects of treatment with antimicrobial photodynamic inhibition (aPI) and antifungal drugs was evaluated. aPI was performed using toluidine blue (TBO) as a photosensitizer and a 630-nm light-emitting diode (LED) light. The antifungals tested were itraconazole and amphotericin B. We evaluated the effects of each approach, aPI or antifungals, against nonmelanized and melanized yeast cells by performing susceptibility tests and by quantifying oxidative and nitrosative bursts during the experiments. aPI reduced nonmelanized cells by 3.0 log units and melanized cells by 1.3 log units. The results showed that melanization protects the fungal cell, probably by acting as a scavenger of nitric oxide and reactive oxygen species, but not of peroxynitrite. Melanin also increased the MICs of itraconazole and amphotericin B, and the drugs were fungicidal for nonmelanized and fungistatic for melanized yeast cells. Our study shows that melanin production by
Paracoccidioides
yeast cells serves a protective function during aPI and treatment with itraconazole and amphotericin B. The results suggest that melanin binds to the drugs, changing their antifungal activities, and also acts as a scavenger of reactive oxygen species and nitric oxide, but not of peroxynitrite, indicating that peroxynitrite is the main radical that is responsible for fungal death after aPI.
Differential Roles of Antimicrobials in the Acquisition of Drug Resistance through Activation of the SOS Response in Acinetobacter baumannii
Authors: Jara Luis M. , Cortés Pilar , Bou Germán , Barbé Jordi , Aranda Jesús
Published: April 2015

The effect of antimicrobials on SOS-mediated mutagenesis induction depends on the bacterial species and the antimicrobial group. In this work, we studied the effect of different families of antimicrobial agents used in clinical therapy against
Acinetobacter baumannii
in the induction of mutagenesis in this multiresistant Gram-negative pathogen. The data showed that ciprofloxacin and tetracycline induce SOS-mediated mutagenesis, whereas colistin and meropenem, which are extensively used in clinical therapy, do not.
Therapeutic Efficacy of Lysophosphatidylcholine in Severe Infections Caused by Acinetobacter baumannii
Authors: Smani Younes , Domínguez-Herrera Juan , Ibáñez-Martínez José , Pachón Jerónimo
Published: April 2015

Due to the significant increase in antimicrobial resistance ofAcinetobacter baumannii, immune system stimulation to block infection progression may be a therapeutic adjuvant to antimicrobial treatment. Lysophosphatidylcholine (LPC), a major component of phospholipids in eukaryotic cells, is involved in immune cell recruitment and modulation. The aim of this study was to show if LPC could be useful for treating infections caused byA. baumannii. A. baumanniiATCC 17978 was used in this study. Levels of serum LPC and levels of the inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-1β, and IL-10 were determined by spectrophotometric assay and enzyme-linked immunosorbent assay (ELISA), respectively, using a murine peritoneal sepsis model in which mice were inoculated with 5.3 log CFU/ml ofA. baumannii. The therapeutic efficacy of LPC againstA. baumanniiin murine peritoneal sepsis and pneumonia models was assessed for 48 h after bacterial infection. At early time points in the murine model of peritoneal sepsis caused byA. baumannii, LPC was depleted and was associated with an increase of inflammatory cytokine release. Preemptive therapy with LPC in murine peritoneal sepsis and pneumonia models markedly enhanced spleen and lung bacterial clearance and reduced the numbers of positive blood cultures and the mouse mortality rates. Moreover, treatment with LPC reduced proinflammatory cytokine production. These data demonstrate that LPC is efficacious as a preemptive treatment in experimental models of peritoneal sepsis and pneumonia caused byA. baumannii.
Characterization of Pre-Antibiotic Era Klebsiella pneumoniae Isolates with Respect to Antibiotic/Disinfectant Susceptibility and Virulence in Galleria mellonella
Authors: Wand Matthew E. , Baker Kate S. , Benthall Gabriel , McGregor Hannah , McCowen James W. I. , Deheer-Graham Ana , Sutton J. Mark
Published: April 2015

The EGD Murray collection consists of approximately 500 clinical bacterial isolates, mainly
Enterobacteriaceae
, isolated from around the world between 1917 and 1949. A number of these “Murray” isolates have subsequently been identified as
Klebsiella pneumoniae
. Antimicrobial susceptibility testing of these isolates showed that over 30% were resistant to penicillins due to the presence of diverse
bla
SHV
β-lactamase genes. Analysis of susceptibility to skin antiseptics and triclosan showed that while the Murray isolates displayed a range of MIC/minimal bactericidal concentration (MBC) values, the mean MIC value was lower than that for more modern
K. pneumoniae
isolates tested. All Murray isolates contained the cation efflux gene
cepA
, which is involved in disinfectant resistance, but those that were more susceptible to chlorhexidine were found to have a 9- or 18-bp insertion in this gene. Susceptibility to other disinfectants, e.g., H
2
O
2
, in the Murray isolates was comparable to that in modern
K. pneumoniae
isolates. The Murray isolates were also less virulent in
Galleria
and had a different complement of putative virulence factors than the modern isolates, with the exception of an isolate related to the modern lineage CC23. More of the modern isolates (41% compared to 8%) are classified as good/very good biofilm formers, but there was overlap in the two populations. This study demonstrated that a significant proportion of the Murray
Klebsiella
isolates were resistant to penicillins before their routine use. This collection of pre-antibiotic era isolates may provide significant insights into adaptation in
K. pneumoniae
in relation to biocide susceptibility.
The Granuloma Response Controlling Cryptococcosis in Mice Depends on the Sphingosine Kinase 1–Sphingosine 1-Phosphate Pathway
Authors: Farnoud Amir M. , Bryan Arielle M. , Kechichian Talar , Luberto Chiara , Del Poeta Maurizio
Published: April 2015

Cryptococcus neoformansis a fungal pathogen that causes pulmonary infections, which may progress into life-threatening meningitis. In commonly used mouse models ofC. neoformansinfections, fungal cells are not contained in the lungs, resulting in dissemination to the brain. We have previously reported the generation of an engineeredC. neoformansstrain (C. neoformansΔgcs1) which can be contained in lung granulomas in the mouse model and have shown that granuloma formation is dependent upon the enzyme sphingosine kinase 1 (SK1) and its product, sphingosine 1-phosphate (S1P). In this study, we have used four mouse models, CBA/J and C57BL6/J (both immunocompetent), Tgε26 (an isogenic strain of strain CBA/J lacking T and NK cells), and SK−/−(an isogenic strain of strain C57BL6/J lacking SK1), to investigate how the granulomatous response and SK1-S1P pathway are interrelated duringC. neoformansinfections. S1P and monocyte chemotactic protein-1 (MCP-1) levels were significantly elevated in the bronchoalveolar lavage fluid of all mice infected withC. neoformansΔgcs1but not in mice infected with theC. neoformanswild type. SK1−/−mice did not show elevated levels of S1P or MCP-1. Primary neutrophils isolated from SK1−/−mice showed impaired antifungal activity that could be restored by the addition of extracellular S1P. In addition, high levels of tumor necrosis factor alpha were found in the mice infected withC. neoformansΔgcs1in comparison to the levels found in mice infected with theC. neoformanswild type, and their levels were also dependent on the SK1-S1P pathway. Taken together, these results suggest that the SK1-S1P pathway promotes host defense againstC. neoformansinfections by regulating cytokine levels, promoting extracellular killing by phagocytes, and generating a granulomatous response.
Sinorhizobium meliloti CtrA Stability Is Regulated in a CbrA-Dependent Manner That Is Influenced by CpdR1
Authors: Schallies Karla B. , Sadowski Craig , Meng Julia , Chien Peter , Gibson Katherine E.
Published: April 2015

CbrA is a DivJ/PleC-like histidine kinase of DivK that is required for cell cycle progression and symbiosis in the alphaproteobacteriumSinorhizobium meliloti. Loss ofcbrAresults in increased levels of CtrA as well as its phosphorylation. While many of the knownCaulobacter crescentusregulators of CtrA phosphorylation and proteolysis are phylogenetically conserved withinS. meliloti, the latter lacks the PopA regulator that is required for CtrA degradation inC. crescentus. In order to investigate whether CtrA proteolysis occurs inS. meliloti, CtrA stability was assessed. During exponential growth, CtrA is unstable and therefore likely to be degraded in a cell cycle-regulated manner. Loss ofcbrAsignificantly increases CtrA stability, but this phenotype is restored to that of the wild type by constitutive ectopic expression of a CpdR1 variant that cannot be phosphorylated (CpdR1D53A). Addition of CpdR1D53Afully suppressescbrAmutant cell cycle defects, consistent with regulation of CtrA stability playing a key role in mediating proper cell cycle progression inS. meliloti. Importantly, thecbrAmutant symbiosis defect is also suppressed in the presence of CpdR1D53A. Thus, regulation of CtrA stability by CbrA and CpdR1 is associated with free-living cell cycle outcomes and symbiosis.

IMPORTANCEThe cell cycle is a fundamental process required for bacterial growth, reproduction, and developmental differentiation. Our objective is to understand how a two-component signal transduction network directs cell cycle events during free-living growth and host colonization. TheSinorhizobium melilotinitrogen-fixing symbiosis with plants is associated with novel cell cycle events. This study identifies a link between the regulated stability of an essential response regulator, free-living cell cycle progression, and symbiosis.
Lack of a significant change in caffeine metabolism in underweight children as determined by the caffeine breath test
Authors: Oshikoya K A , Sammons H , Smith K , Choonara I
Published: April 2015

Objective

Limited data from pharmacokinetic studies in underweight and severely malnourished children have indicated an impaired activity of their hepatic enzymes. We used the caffeine breath test to assess the metabolising activity of cytochrome P450 1A2 (CYP1A2) enzyme in underweight children.

Methods

Underweight children from the paediatric outpatient clinic, Lagos State University Teaching Hospital, Ikeja in Nigeria, were studied. After an overnight fast, 15 underweight children took 3 mg/kg labelled caffeine orally. Breath samples were collected in duplicate at −20, −10 and −1 min and at 15 min intervals for 2 h. The mean cumulative per cent dose recovered (CPDR) of labelled caffeine in the expired carbon dioxide was determined over the study period. This was repeated after 2–6 weeks of nutritional rehabilitation.

Results

The mean areas under the enrichment-time curve before and after nutritional rehabilitation were 0.539±0.320 and 0.620±0.322 atom per cent excess minute, respectively. The difference between the two values was not statistically significant (p=0.528). The mean CPDR in the exhaled carbon dioxide of the underweight children over a period of 2 h was 7.56±4.01% and 7.95±3.68% before and after nutritional rehabilitation, respectively, and there was no significant difference in the mean values (p=0.603).

Conclusions

The metabolism of caffeine was not significantly affected in underweight children compared with after 2–6 weeks of nutritional rehabilitation. This suggests that hepatic CYP1A2-metabolising activity was not significantly impaired in underweight children.
Focused image-guided parathyroidectomy in the current management of primary hyperparathyroidism
Authors: Langusch Catherine C , Norlen Olov , Titmuss Angela , Donoghue Kim , Holland Andrew J A , Shun Albert , Delbridge Leigh
Published: April 2015

Objective

Primary hyperparathyroidism (PHPT) in childhood and adolescence has been considered a different disease to that seen in adults, with predominantly familial aetiology mandating open exploration to exclude parathyroid hyperplasia in contrast to the adoption of focused image-guided parathyroidectomy (FP) in adults.

Study design

A retrospective cohort study in a tertiary referral hospital setting of all children and adolescents (<18 years) undergoing parathyroid surgery for PHPT. Data were obtained from a dedicated endocrine surgery database and hospital medical records.

Results

Over the 35-year study period (1980–2014), there were 31 patients who underwent parathyroidectomy for PHPT. 3 patients were from known multiple endocrine neoplasia type 1 syndrome (MEN1) families, 3 had an isolated family history of PHPT and 25 were sporadic. In the sporadic group, 24 (96%) presented with symptomatic hypercalcaemia, affecting the gastrointestinal, musculoskeletal, genitourinary or neuropsychiatric systems. In the 25 patients with sporadic PHPT, nine (36%) had FP with a single adenoma removed with a 100% initial cure rate. Sixteen patients (64%) in the sporadic group had an open exploration: 14 had single gland disease while 2 patients required a second procedure to achieve a final cure rate of 100%. Of the three patients with MEN1, one was cured, one has persistent hyperparathyroidism after FP and the third has permanent hypoparathyroidism after open exploration.

Conclusions

The majority of children and adolescents with PHPT have symptomatic disease due to a single adenoma. They can therefore be managed in a similar fashion to their adult counterparts with preoperative localisation studies aiming to permit FP in a day case setting.
Does the quality and outcomes framework reduce psychiatric admissions in people with serious mental illness? A regression analysis
Authors: Gutacker Nils , Mason Anne R , Kendrick Tony , Goddard Maria , Gravelle Hugh , Gilbody Simon , Aylott Lauren , Wainwright June , Jacobs Rowena
Published: April 2015

Background

The Quality and Outcomes Framework (QOF) incentivises general practices in England to provide proactive care for people with serious mental illness (SMI) including schizophrenia, bipolar disorder and other psychoses. Better proactive primary care may reduce the risk of psychiatric admissions to hospital, but this has never been tested empirically.

Methods

The QOF data set included 8234 general practices in England from 2006/2007 to 2010/2011. Rates of hospital admissions with primary diagnoses of SMI or bipolar disorder were estimated from national routine hospital data and aggregated to practice level. Poisson regression was used to analyse associations.

Results

Practices with higher achievement on the annual review for SMI patients (MH9), or that performed better on either of the two lithium indicators for bipolar patients (MH4 or MH5), had more psychiatric admissions. An additional 1% in achievement rates for MH9 was associated with an average increase in the annual practice admission rate of 0.19% (95% CI 0.10% to 0.28%) or 0.007 patients (95% CI 0.003 to 0.01).

Conclusions

The positive association was contrary to expectation, but there are several possible explanations: better quality primary care may identify unmet need for secondary care; higher QOF achievement may not prevent the need for secondary care; individuals may receive their QOF checks postdischarge rather than prior to admission; individuals with more severe SMI may be more likely to be registered with practices with better QOF performance; and QOF may be a poor measure of the quality of care for people with SMI.
The detrimental effects of iron on the joint: a comparison between haemochromatosis and haemophilia
Authors: van Vulpen Lize F D , Roosendaal Goris , van Asbeck B Sweder , Mastbergen Simon C , Lafeber Floris P J G , Schutgens Roger E G
Published: April 2015

Joint damage due to (recurrent) joint bleeding in haemophilia causes major morbidity. Although the exact pathogenesis has not been fully elucidated, a central role for iron is hypothesised. Likewise, in hereditary haemochromatosis joint destruction is caused by iron overload. A comparison between these types of arthropathy could provide more insight in the influence of iron in inducing joint damage. A literature review was performed to compare both disorders with respect to their clinical and histological characteristics, and preclinical studies on the influence of iron on different joint components were reviewed. Similarities in the features of arthropathy in haemochromatosis and haemophilia are cartilage degeneration, subchondral bone changes with osteophyte and cyst formation, and osteoporosis. In both disorders synovial inflammation and proliferation are seen, although this is much more explicit in haemophilia. Other substantial differences are the age at onset, the occurrence of chondrocalcinosis radiographically and calcium pyrophosphate dihydrate deposition disease in haemochromatosis, and a rapid progression with joint deformity and neovascularisation in haemophilia. Preclinical studies demonstrate detrimental effects of iron to all components of the joint, resulting in synovial inflammation and hyperplasia, chondrocyte death, and impaired osteoblast function. These effects, particularly the synovial changes, are aggravated in the presence of a pro-inflammatory signal, which is prominent in haemophilic arthropathy and minimal in haemochromatosis. Additional research is needed to further specify the role of iron as a specific target in treating these types of arthropathy.
Republished: Republished: Rebleeding of a neck remnant in a case of ruptured aneurysm initially treated with coils
Authors: Benaissa Azzedine , Pierot Laurent
Published: April 2015

The follow-up and indications for retreatment of intracranial aneurysms treated endovascularly are still a matter of debate. We report the case of a patient with a ruptured aneurysm who was treated twice with coils and regularly followed up with MRI/MR angiography which showed a neck remnant that finally rebled.
MRI using ultrasmall superparamagnetic particles of iron oxide in patients under surveillance for abdominal aortic aneurysms to predict rupture or surgical repair: MRI for abdominal aortic aneurysms to predict rupture or surgery—the MA3RS study
Authors: McBride Olivia M B , Berry Colin , Burns Paul , Chalmers Roderick T A , Doyle Barry , Forsythe Rachael , Garden O James , Goodman Kirsteen , Graham Catriona , Hoskins Peter , Holdsworth Richard , MacGillivray Thomas J , McKillop Graham , Murray Gordon , Oatey Katherine , Robson Jennifer M J , Roditi Giles , Semple Scott , Stuart Wesley , van Beek Edwin J R , Vesey Alex , Newby David E
Published: April 2015

Introduction

Population screening for abdominal aortic aneurysms (AAA) halves the associated mortality and has led to the establishment of national screening programmes. Prediction of aneurysm growth and rupture is challenging and currently relies on serial diameter measurements with ultrasound. Recently, a novel MRI-based technique using ultrasmall superparamagnetic particles of iron oxide (USPIO) has demonstrated considerable promise as a method of identifying aneurysm inflammation and expansion.

Methods and analysis

The MA3RS study is a prospective observational multicentre cohort study of 350 patients with AAA in three centres across Scotland. All participants will undergo MRI with USPIO and aneurysm expansion will be measured over 2 years with CT in addition to standard clinical ultrasound surveillance. The relationship between mural USPIO uptake and subsequent clinical outcomes, including expansion, rupture and repair, will be evaluated and used to determine whether the technique augments standard risk prediction markers. To ensure adequate sensitivity to answer the primary question, we need to observe 130 events (composite of rupture or repair) with an estimated event rate of 41% over 2 years of follow-up. The MA3RS study is currently recruiting and expects to report in 2017.

Discussion

This is the first study to evaluate the use of USPIO-enhanced MRI to provide additional information to aid risk prediction models in patients with AAA. If successful, this study will lay the foundation for a large randomised controlled trial targeted at applying this technique to determine clinical management.

Trial registration number

Current Controlled Trials:ISRCTN76413758.
Thermodynamic and kinetic properties of the adsorption of 4-nitrophenol on graphene from aqueous solution
Authors: Ismail Ali Issa
Published: April 2015

Graphene is a newly discovered material and is considered to be the new wonder material for many applications. The recent possibility of obtaining pure and fully characterized graphene opens the door to the study of the adsorption of toxic materials on graphene. The adsorption behavior of p-nitrophenol on graphene was studied in aqueous medium. The effect of each of pH, temperature, and dosage was emphasized. The highest calculated adsorption capacity of 4-nitrophenol was found to be 15.5 mg/g, assuming Langmuir fitting starting from 11.1 mg/g initial concentration at 298 K and pH = 6. Fitting the data using the Freundlich isotherm model predicted a favorable adsorption process (n > 1). The rise and saturation areas of the isotherms were fitted as pseudo first-order and pseudo second-order processes, respectively, with relatively good fit (k1 = 0.0023/s, k2 = 0.68 g mg−1 s−1). The thermodynamic properties indicated a spontaneous and exothermic process.
Structure, vibrational spectroscopy, and photochemistry of 5-phenoxy-1-phenyltetrazole in argon and nitrogen cryomatrices
Authors: Borba A. , Cabral L.I.L. , Fausto R. , Cristiano M.L.S.
Published: April 2015

The molecular structure, infrared spectra, and photochemistry of 5-phenoxy-1-phenyltetrazole (5PPT) isolated in argon and N2 cryogenic matrices were investigated by infrared spectroscopy and theoretical calculations (DFT(B3LYP)/6-311++G(d,p)). Calculations yield two dissimilar minima on the potential energy surface of the molecule, both being eightfold degenerate by symmetry and belonging to the C1 symmetry point group. Extensive analysis of the potential energy landscape of the molecule was performed. Upon consideration of the zero-point vibrational correction to the energy, the calculations predict that the higher energy minimum shall relax barrierlessly to the lower energy form, leading to conclude that the compound exists in a single conformer in the gas phase. Accordingly, a single conformer was observed and fully characterized spectroscopically upon isolation of the monomer of the compound in argon and nitrogen cryomatrices. UV-laser irradiation (λ = 250 nm) of matrix-isolated 5PPT leads to photocleavage of the tetrazole ring, with release of N2 and formation of the corresponding carbodiimide.
A state-space approach for detecting growth variation and application to North Pacific groundfish
Authors: Stawitz Christine C. , Essington Timothy E. , Branch Trevor A. , Haltuch Melissa A. , Hollowed Anne B. , Spencer Paul D.
Published: April 2015

Understanding demographic variation in recruitment and somatic growth is key to improving our understanding of population dynamics and forecasting ability. Although recruitment variability has been extensively studied, somatic growth variation has received less attention, in part because of difficulties in modeling growth from individual size-at-age estimates. Here we develop a Bayesian state-space approach to test for the prevalence of alternative forms of growth rate variability (e.g., annual, cohort-level, or in the first year recruited to the fishery) in size-at-age data. We apply this technique to 29 Pacific groundfish species across the California Current, Gulf of Alaska, and Bering Sea – Aleutian Islands marine ecosystems. About 40% of modeled stocks were estimated to exhibit temporal growth variation. In the majority of stocks, growth trends fluctuated annually across ages in a single year, suggesting that either there are shared environmental features that dictate growth across multiple ages or the presence of some systematic (within-year) observation errors. This method represents a novel way to use size-at-age data from fishery or other sources to test hypotheses about growth dynamics variability.
Decays $D^+_{(s)}\to \pi(K)^{+}\ell^+\ell^-$ and D0→ℓ+ℓ- in the MSSM with and without R-parity
Authors: Wang Ru-Min , Sheng Jin-Huan , Zhu Jie , Fan Ying-Ying , Xu Yuan-Guo
Published: April 2015

We study the rare decays D+→π+ℓ+ℓ-, [Formula: see text] and D0→ℓ+ℓ-(ℓ = e, μ) in the minimal supersymmetic standard model with and without R-parity. Using the strong constraints on relevant supersymmetric parameters from [Formula: see text] mixing and [Formula: see text] decay, we examine constrained supersymmetry contributions to relevant branching ratios, direct CP violations and ratios of [Formula: see text] and [Formula: see text] decay rates. We find that both R-parity conserving LR as well as RL mass insertions and R-parity violating squark exchange couplings have huge effects on the direct CP violations of [Formula: see text], moreover, the constrained LR and RL mass insertions still have obvious effects on the ratios of [Formula: see text] and [Formula: see text] decay rates. The direct CP asymmetries and the ratios of [Formula: see text] and [Formula: see text] decay rates are very sensitive to both moduli and phases of relevant supersymmetric parameters. In addition, the differential direct CP asymmetries of [Formula: see text] are studied in detail.
Quintessence and effective AdS brane geometries
Authors: Pandey K. Priyabrat , Singh Abhishek K. , Singh Sunita , Kar Supriya
Published: April 2015

A geometric torsion dynamics leading to an effective curvature in a second-order formalism on a D4-brane is revisited with a renewed interest. We obtain two effective AdS 4 brane geometries on a vacuum created pair of [Formula: see text]-brane. One of them is shown to describe an AdS Schwarzschild spinning black hole and the other is shown to describe a spinning black hole bound state. It is argued that a D-instanton in a vacuum created anti-D3-brane within a pair may describe a quintessence. It may seem to incorporate a varying vacuum energy density in a brane universe. We consider the effective curvature scalar on S1 × S1 to analyze torsionless geometries on a vacuum created pair of [Formula: see text]-brane. The emergent AdS 3 brane is shown to describe a Schwarzschild and a Reissner–Nordstrom (RN) geometries in the presence of extra dimension(s).
Phase transition and thermodynamic properties of beryllium telluride under high pressure
Authors: Guo Zhi-Cheng , Luo Fen , Zhang Xiu-Lu , Liu Cheng-An , Cai Ling-Cang
Published: April 2015

A theoretical investigation on structural, dynamical, phase diagram and thermodynamic properties of beryllium telluride (BeTe) under high pressure and temperature is presented in the framework of density functional theory. The calculated structural parameters of BeTe in both zinc blende (ZB) and nickel arsenide (NiAs) structures are in reasonable agreement with available experimental data and previous theoretical work. The phonon dispersion relations, dielectric tensor and Born effective charge are investigated within the density functional perturbation theory (DFPT). The investigation of the phase diagram indicated that the NiAs structure BeTe becomes stable at high pressure and temperature. Based on the quasiharmonic Debye model, the pressure and temperature dependences of bulk modulus, Grüneisen parameter, Debye temperature, specific heat and thermal expansion coefficient are all successfully obtained. We hope that the theoretical results reported here can give more insight into the structural and thermodynamic properties of other semiconductors at high temperature and pressure.
Cyclic degradation of titanium–tantalum high-temperature shape memory alloys — the role of dislocation activity and chemical decomposition
Authors: Niendorf T. , Krooß P. , Somsen C. , Rynko R. , Paulsen A. , Batyrshina E. , Frenzel J. , Eggeler G. , Maier H. J.
Published: April 2015

Titanium–tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel–titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium–tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation processes and chemical decomposition of the matrix at grain boundaries also play a major role.
Graphene Mechanics: Current Status and Perspectives
Authors: Galiotis Costas , Frank Otakar , Koukaras Emmanuel N. , Sfyris Dimitris
Published: April 2015

The mechanical properties of 2D materials such as monolayer graphene are of extreme importance for several potential applications. We summarize the experimental and theoretical results to date on mechanical loading of freely suspended or fully supported graphene. We assess the obtained axial properties of the material in tension and compression and comment on the methods used for deriving the various reported values. We also report on past and current efforts to define the elastic constants of graphene in a 3D representation. Current areas of research that are concerned with the effect of production method and/or the presence of defects upon the mechanical integrity of graphene are also covered. Finally, we examine extensively the work related to the effect of graphene deformation upon its electronic properties and the possibility of employing strained graphene in future electronic applications.
Making Progress on Foreign Aid
Authors: Qian Nancy
Published: April 2015

Foreign aid is one of the most important policy tools that rich countries use to help poor countries improve population well-being and facilitate economic and institutional development. The empirical evidence on its benefits is mixed and has generated much controversy. This article presents descriptive statistics that show that foreign aid to very poor countries accounts for very little of total global aid; reviews the evidence that foreign aid is often determined by the objectives of donor countries rather than the needs of recipient countries; argues that the evidence on the impact of aggregate foreign aid is hindered by problems of measurement and identification, which partly result from the heterogeneous nature of aid; and discusses recent studies using natural and randomized experiments to examine narrowed definitions of aid on more disaggregated outcomes.
The Power of Materials Science Tools for Gaining Insights into Organic Semiconductors
Authors: Treat Neil D. , Westacott Paul , Stingelin Natalie
Published: April 2015

The structure of organic semiconductors can be complex because features from the molecular level (such as molecular conformation) to the micrometer scale (such as the volume fraction and composition of phases, phase distribution, and domain size) contribute to the definition of the optoelectronic landscape of the final architectures and, hence, to device performance. As a consequence, a detailed understanding of how to manipulate molecular ordering, e.g., through knowledge of relevant phase transitions, of the solidification process, of relevant solidification mechanisms, and of kinetic factors, is required to induce the desired optoelectronic response. In this review, we discuss relevant structural features of single-component and multicomponent systems; provide a case study of the multifaceted structure that polymer:fullerene systems can adopt; and highlight relevant solidification mechanisms such as nucleation and growth, liquid-liquid phase separation, and spinodal decomposition. In addition, cocrystal formation, solid solutions, and eutectic systems are treated and their relevance within the optoelectronic area emphasized.
The Wayward Hawaiian Boy Returns Home
Authors: Gonsalves Dennis
Published: April 2015

This chapter represents a travelog of my life and career and the philosophical points I acquired along the way. I was born on a sugar plantation on the island of Hawaii and early on had a stuttering problem. I attended the Kamehameha Schools and received my BS and MS degrees from the University of Hawaii and my Ph.D. from the University of California at Davis. I link my life and career to various principles and events, some of which are: the importance of positioning oneself; going for the big enchilada; music, the international language; the red zone of biotechnology; the human side of biotechnology; the transgenic papaya story; and my leadership time at USDA in Hawaii. The guiding light throughout my career were the words from Drs. Eduardo Trujillo and Robert Shepherd, respectively, “Dennis, don't just be a test tube scientist, do something to help people” and “Now tell me, what have you really accomplished?”
The Empiricists' Insurgency
Authors: Berman Eli , Matanock Aila M.
Published: April 2015

Research on insurgency has been invigorated during this past decade by better data, improved methods, and the urgency of understanding active engagements in Iraq and Afghanistan. This “empiricists' insurgency” reinforces a classic literature on the essential role of civilians while challenging older theories about how they affect conflict outcomes. It provides a general framework describing “irregular” insurgencies (where government capacity exceeds rebel capacity), which is analytically cohesive and empirically tested using subnational data from multiple conflicts. The new research provides guidance on intervention design, including governance improvement, development programs, and rules of engagement. The design of interventions matters: Some key evidence comes from measuring the effects of misguided policies. The framework may enable better conceived and implemented interventions, including foreign engagements with and without troop deployment, depending on the type of insurgency and mindful of political limitations. We position these findings in the literature and highlight directions for future research, including legal aspects of countering insurgency.
Social Networks in Developing Countries
Authors: Chuang Yating , Schechter Laura
Published: April 2015

Social networks function as an important safety net in developing countries, which often lack formal financial instruments. Such networks are also an important source of information in developing countries with relatively low access to the Internet and literacy rates. We review the empirical literature that uses explicit social network data collected in developing countries. We focus on social networks as conduits for both monetary transfers and information. We also briefly discuss the network-formation literature and comment on data collection strategies, mentioning some areas we believe to be especially ripe for future study.
Exercise effects on postprandial glucose metabolism in type 1 diabetes: a triple-tracer approach
Authors: Mallad Ashwini , Hinshaw Ling , Schiavon Michele , Dalla Man Chiara , Dadlani Vikash , Basu Rita , Lingineni Ravi , Cobelli Claudio , Johnson Matthew L. , Carter Rickey , Kudva Yogish C. , Basu Ananda
Published: April 2015

To determine the effects of exercise on postprandial glucose metabolism and insulin action in type 1 diabetes (T1D), we applied the triple tracer technique to study 16 T1D subjects on insulin pump therapy before, during, and after 75 min of moderate-intensity exercise (50% V̇o2max) that started 120 min after a mixed meal containing 75 g of labeled glucose. Prandial insulin bolus was administered as per each subject's customary insulin/carbohydrate ratio adjusted for meal time meter glucose and the level of physical activity. Basal insulin infusion rates were not altered. There were no episodes of hypoglycemia during the study. Plasma dopamine and norepinephrine concentrations rose during exercise. During exercise, rates of endogenous glucose production rose rapidly to baseline levels despite high circulating insulin and glucose concentrations. Interestingly, plasma insulin concentrations increased during exercise despite no changes in insulin pump infusion rates, implying increased mobilization of insulin from subcutaneous depots. Glucagon concentrations rose before and during exercise. Therapeutic approaches for T1D management during exercise will need to account for its effects on glucose turnover, insulin mobilization, glucagon, and sympathetic response and possibly other blood-borne feedback and afferent reflex mechanisms to improve both hypoglycemia and hyperglycemia.
Automated Design Space Exploration with Aspen
Authors: Spafford Kyle L. , Vetter Jeffrey S.
Published: April 2015

Architects and applications scientists often use performance models to explore a multidimensional design space of architectural characteristics, algorithm designs, and application parameters. With traditional performance modeling tools, these explorations forced users to first develop a performance model and then repeatedly evaluate and analyze the model manually. These manual investigations proved laborious and error prone. More importantly, the complexity of this traditional process often forced users to simplify their investigations. To address this challenge of design space exploration, we extend our Aspen (Abstract Scalable Performance Engineering Notation) language with three new language constructs: user-defined resources, parameter ranges, and a collection of costs in the abstract machine model. Then, we use these constructs to enable automated design space exploration via a nonlinear optimization solver. We show how four interesting classes of design space exploration scenarios can be derived from Aspen models and formulated as pure nonlinear programs. The analysis tools are demonstrated using examples based on Aspen models for a three-dimensional Fast Fourier Transform, the CoMD molecular dynamics proxy application, and the DARPA Streaming Sensor Challenge Problem. Our results show that this approach can compose and solve arbitrary performance modeling questions quickly and rigorously when compared to the traditional manual approach.
Fuzzy Clustering Using the Convex Hull as Geometrical Model
Authors: Liparulo Luca , Proietti Andrea , Panella Massimo
Published: April 2015

A new approach to fuzzy clustering is proposed in this paper. It aims to relax some constraints imposed by known algorithms using a generalized geometrical model for clusters that is based on the convex hull computation. A method is also proposed in order to determine suitable membership functions and hence to represent fuzzy clusters based on the adopted geometrical model. The convex hull is not only used at the end of clustering analysis for the geometric data interpretation but also used during the fuzzy data partitioning within an online sequential procedure in order to calculate the membership function. Consequently, a pure fuzzy clustering algorithm is obtained where clusters are fitted to the data distribution by means of the fuzzy membership of patterns to each cluster. The numerical results reported in the paper show the validity and the efficacy of the proposed approach with respect to other well-known clustering algorithms.
Anti-Lung Cancer Activity of the Curcumin Analog JZ534 In Vitro
Authors: Wu Jianzhang , Cai Zhijian , Wei Xiaoyan , Chen Minxiao , Ying Shilong , Shi Lingyi , Xu Ren-Ai , He Fan , Liang Guang , Zhang Xiuhua
Published: April 2015

This study investigated the anticancer effect of the curcumin analog JZ534 on lung cancer cell lines H460, A549, H1975, and HCC827. The antiproliferation effect of JZ534 was measured through the methylthiazoletetrazolium assay, and cell colony formation was observed. Cell cycle and apoptosis were determined by flow cytometry, and the preliminary mechanism was studied by Western blot. Results showed that JZ534 significantly inhibited the vitality and colony formation of lung cancer cells. JZ534 induced the G2/M cell cycle arrest of the cancer cells and suppressed the expression of cycle-related proteins, including cyclin B1 and Cdc2. Meanwhile, JZ534 induced cell apoptosis and upregulated the expression of apoptosis-related proteins, including cleaved caspase-3, Bax, and p53. At the same dose, JZ534 showed better antitumor activity than curcumin. These results suggest that JZ534 exhibits excellent anti-lung cancer activity by inhibiting the growth and inducing the apoptosis of lung cancer cells. Therefore, JZ534 is a promising lead compound for cancer treatment.
Rhabdomyosarcoma of the Upper Lip in an Adult Patient
Authors: Cobanoglu Bengu , Simsek Mustafa , Senol Serkan
Published: April 2015

Rhabdomyosarcoma (RMS) is a high-grade, malignant mesenchymal neoplasm. These tumors represent the most common soft tissue sarcomas of children and adolescents. RMS is uncommon on the lip and it is rarely seen in adults. Here, we report a rare case of primary RMS, embryonal type, occurring on the upper lip in a 27-year-old female.
Joint Power Allocation at the Base Station and the Relay for Untrusted Relay Cooperation OFDMA Network
Authors: Jiang Weiheng , Feng Wenjiang
Published: April 2015

The secure communication that multiple OFDMA-based cell-edge mobile stations (MS) can only transmit confidential messages to base station (BS) through an untrusted intermediate relay (UR) is discussed. Specifically, with the destination-based jamming (DBJ) scheme and fixed MS transmission power assumption, our focus is on the joint BS and US power allocation to maximize system sum secrecy rate. We first analyze the challenges in solving this problem. The result indicates that our nonconvex joint power allocation is equivalent to a joint MS access control and power allocation. Then, by problem relaxation and the alternating optimization approach, two suboptimal joint MS access control and power allocation algorithms are proposed. These algorithms alternatively solve the subproblem of joint BS and UR power allocation and the subproblem of MS selection until system sum secrecy rate is nonincreasing. In addition, the convergence and computational complexity of the proposed algorithms are analyzed. Finally, simulations results are presented to demonstrate the performance of our proposed algorithms.
Feasibility and Safety of Overtubes for PEG-Tube Placement in Patients with Head and Neck Cancer
Authors: Musumba Crispin O. , Hsu Julia , Ahlenstiel Golo , Tutticci Nicholas J. , Nanda Kavinderjit S. , van der Poorten David , Lee Eric Y. , Kwan Vu
Published: April 2015

Background. Percutaneous endoscopic gastrostomy (PEG) placement using the “pull” technique is commonly utilized for providing nutritional support in head and neck cancer (HNC) patients, but it may be complicated by peristomal metastasis in up to 3% of patients. Overtube-assisted PEG placement might reduce this risk. However, this technique has not been systemically studied for this purpose to date.Methods. Retrospective analysis of consecutive patients with HNC who underwent overtube-assisted PEG placement at Westmead Hospital, Australia, between June 2011 and December 2013. Data were extracted from patients’ endoscopy reports and case notes. We present our technique for PEG insertion and discuss the feasibility and safety of this method.Results. In all 53 patients studied, the PEG tubes were successfully placed using 25 cm long flexible overtubes, in 89% prophylactically (before commencing curative chemoradiotherapy), and in 11% reactively (for treatment of tumor related dysphagia or weight loss). During a median follow-up period of 16 months, 3 (5.7%) patients developed peristomal infection and 3 others developed self-limiting peristomal pain. There were no cases of overtube-related adverse events or overt cutaneous metastases observed.Conclusions. Overtube-assisted PEG placement in patients with HNC is a feasible, simple, and safe technique and might be effective for preventing cutaneous metastasis.
Modulation of Hippocampal Neural Plasticity by Glucose-Related Signaling
Authors: Mainardi Marco , Fusco Salvatore , Grassi Claudio
Published: April 2015

Hormones and peptides involved in glucose homeostasis are emerging as important modulators of neural plasticity. In this regard, increasing evidence shows that molecules such as insulin, insulin-like growth factor-I, glucagon-like peptide-1, and ghrelin impact on the function of the hippocampus, which is a key area for learning and memory. Indeed, all these factors affect fundamental hippocampal properties including synaptic plasticity (i.e., synapse potentiation and depression), structural plasticity (i.e., dynamics of dendritic spines), and adult neurogenesis, thus leading to modifications in cognitive performance. Here, we review the main mechanisms underlying the effects of glucose metabolism on hippocampal physiology. In particular, we discuss the role of these signals in the modulation of cognitive functions and their potential implications in dysmetabolism-related cognitive decline.
How Do Families of Children with Down Syndrome Perceive Speech Intelligibility in Turkey?
Authors: Toğram Bülent
Published: April 2015

Childhood verbal apraxia has not been identified or treated sufficiently in children with Down syndrome but recent research has documented that symptoms of childhood verbal apraxia can be found in children with Down syndrome. But, it is not routinely diagnosed in this population. There is neither an assessment tool in Turkish nor any research on childhood verbal apraxia although there is a demand not only for children with Down syndrome but also for normally developing children. The study examined if it was possible to determine oral-motor difficulties and childhood verbal apraxia features in children with Down syndrome through a survey. The survey was a parental report measure. There were 329 surveys received. Results indicated that only 5.6% of children with Down syndrome were diagnosed with apraxia, even though many of the subject children displayed clinical features of childhood verbal apraxia. The most frequently reported symptoms of childhood verbal apraxia in literature were displayed by the children with Down syndrome in the study. Parents could identify childhood verbal apraxia symptoms using parent survey. This finding suggests that the survey can be developed that could serve as a screening tool for a possible childhood verbal apraxia diagnosis in Turkey.