bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation between fractional anisotropy and motor outcomes in one‐year‐old infants with periventricular brain injury
Authors: Madhavan Sangeetha , Campbell Suzann K. , Campise‐Luther Rose , Gaebler‐Spira Deborah , Zawacki Laura , Clark April , Boynewicz Kara , Kale Dipti , Bulanda Michelle , Yu Jinsheng , Sui Yi , Zhou Xiaohong Joe
Published: October 2013

Purpose

To determine whether motor outcomes of an exercise intervention beginning at 2 months corrected age (CA) in children with periventricular brain injury (PBI) are correlated with fractional anisotropy (FA) measures derived from diffusion tensor imaging (DTI) at 12 months CA.

Materials and Methods

DTI was performed in eight infants with PBI who were randomly assigned to kicking and treadmill stepping exercise or a no‐training condition. Development was assessed using the Alberta Infant Motor Scale (AIMS) and the Gross Motor Function Classification System (GMFCS). FA values were derived from regions of interest (ROIs) in the middle third of the posterior limb of the internal capsule (PLIC) and the posterior thalamic radiation (PTR).

Results

Significant correlations were observed between motor development and FA measures. For PLIC, the correlation coefficients were 0.82 between FA and AIMS, and −0.92 between FA and GMFCS, while for PTR the corresponding correlation coefficients were 0.73 and −0.80, respectively.

Conclusion

Results of this study suggest that quantitative evaluation of white matter tracts using DTI at 12 months CA may be useful for assessment of brain plasticity in children. J. Magn. Reson. Imaging 2014;39:949–957. © 2013 Wiley Periodicals, Inc.
Regional perfusion imaging using pTILT
Authors: Ouyang Cheng , Sutton Bradley P.
Published: October 2013

Purpose

To demonstrate the feasibility that the pseudo‐continuous transfer insensitive labeling technique (pTILT) sequence can be modified to achieve regional perfusion imaging by either vessel‐encoded or vessel‐selective pTILT, similar to the regional perfusion imaging sequences using pseudo‐continuous arterial spin labeling (pCASL).

Materials and Methods

Static phantom experiments were carried out to investigate the selectivity and efficiency of region‐specific labeling by pTILT. The ability of the modified pTILT sequences to separate perfusion territories was also examined at two levels of the arterial tree on four healthy subjects: (i) the left and right internal carotid arteries (ICAs) and (ii) individual vascular territories of arteries above the circle of Willis (anterior cerebral artery [ACA], left and right middle cerebral arteries [MCAs]).

Results

In the phantom study, compared with non–region‐specific pTILT, a labeling efficiency of 0.92 and 0.88 was measured at the target vessels using vessel‐encoded and vessel‐selective pTILT, respectively. In human studies, the perfusion territories of ACA, left and right MCA branches with estimated CBF of 74.5 ± 26.1, 65.9 ± 7.2, and 72.3 ± 14.5 mL/100 g/min, respectively, as well as more general left/right end territories (76.8 ± 12.7 and 72.8 ± 7.2 mL/100 g/min), were clearly delineated by the modified pTILT sequences for regional perfusion imaging.

Conclusion

Two regional perfusion imaging modules (vessel‐encoded and vessel‐selective) used in pCASL can also be adapted into the pTILT sequence, and our results confirmed that the region‐specific pTILT sequence is capable of regional perfusion imaging to separate perfusion territories of major cerebral arteries. J. Magn. Reson. Imaging 2014;40:192–199. © 2013 Wiley Periodicals, Inc.
Anti‐HBs seroconversion during treatment with entecavir in a patient with chronic hepatitis B virus infection on hemodialysis
Authors: Spaziante Martina , Biliotti Elisa , Grieco Stefania , Palazzo Donatella , Esvan Rozenn , Taliani Gloria
Published: October 2013

Hepatitis B (HBV) virus infection is one of the most important causes of liver disease in patients with end‐stage renal failure on hemodialysis. The natural history of chronic HBV infection acquired in childhood starts with an immune tolerant phase, followed by an immune clearance phase that may lead to the inactive carrier state or the development of chronic liver disease. Information on antiviral therapy administered very early during the immune clearance phase are lacking and no data exist on the treatment of early immune activation in the hemodialysis setting. This report describes the case of a patient affected by end‐stage renal failure and HBeAg‐positive chronic HBV virus infection treated very early during the immune clearance phase of HBV infection with an adjusted‐dose of nucleoside analogue entecavir. The patient achieved a very rapid HBV‐DNA undetectability, anti‐HBe, and anti‐HBs seroconversion. This is the first report of antiviral therapy with entecavir started during the immune reactive phase of HBV infection in a patient on hemodialysis and it suggests that antiviral treatment can enhance the effects of host immune activation resulting in biochemical, serological, and viral response, even in end‐stage renal failure patients with partial immunodeficiency. Antiviral therapy with entecavir in the setting of hemodialysis was safe and well tolerated. J. Med. Virol. 86:139–143, 2014. © 2013 Wiley Periodicals, Inc.
Irreproducible positive results on the Cobas AmpliPrep/Cobas TaqMan HIV‐1 Qual test are different qualitatively from confirmed positive results
Authors: Maritz Jean , van Zyl Gert U. , Preiser Wolfgang
Published: October 2013

Criteria that define low positive results on the COBAS® AmpliPrep/COBAS® TaqMan (CAP/CTM) HIV‐1 Qual test as inconclusive have been adopted by all academic centres in South Africa that conduct infant HIV PCR, following previous investigations that showed poor specificity of these results. Retesting all inconclusive specimens has considerable cost implications. Therefore, it was attempted to characterise such inconclusive results, by comparing those that prove to be either negative or positive on follow‐up testing. This retrospective, laboratory‐based study found that 193 of 211 (91.5%) patients with previous inconclusive results (defined as reported positive by CAP/CTM but with cycle threshold [Ct] values of >32 and/or fluorescence intensity [FI] values of <5) tested negative and only 18 (8.5%) tested positive using independently obtained follow‐up samples after a median of 28 days. The only significant independent predictor of a later positive result was a higher FI value (3.326 vs. 0.495, P < 0.0001), whereas Ct values were not predictive independently. Specimens from patients negative on follow‐up testing differed qualitatively from specimens that proved to be true positives. As the lower FI values in false‐positive compared to true‐positive results probably are indicative of a non‐specific signal, the incorporation of stringent amplification slope criteria in the assay's test definition file may improve correct classification and thus reduce the need for repeat testing of a large number of inconclusive specimens. J. Med. Virol. 86:82–87, 2014. © 2013 Wiley Periodicals, Inc.
A novel mouse model of trauma induced heterotopic ossification
Authors: Liu Xuhui , Kang Heejae , Shahnazari Mohammad , Kim Hubert , Wang Liping , Larm Olla , Adolfsson Lars , Nissenson Robert , Halloran Bernard
Published: October 2013

Severe soft tissue trauma is associated with heterotopic ossification (HO), the abnormal deposition of bone at extra‐skeletal sites. The pathophysiology of the development of trauma‐induced HO remains largely unknown due in part to the lack of appropriate animal models. In this study, we sought to develop a new trauma‐induced HO mouse model using muscle impact injury combined with low dose BMP‐2. BMP‐2 at doses ranging from 0 to 2 µg was injected into quadriceps muscles of adult male C57/BL6 mice. Animals then received a one‐time quadriceps impaction injury to mimic the trauma associated with severe injuries. HO was monitored using in vivo microCT scanning at 1, 2, 4, and 8 weeks after treatment. After trauma, the expression of BMP‐2, ‐4, BMP receptor 1, SOX9 and RUNX2 were increased in muscle. Although little or no HO was observed in mice receiving 1 µg BMP‐2, combining this dose with muscle trauma produced an abundance of HO. At higher doses of BMP‐2, trauma did not augment mineral deposition. These results suggest that BMP‐2 signaling can sensitize muscle to trauma‐induced HO. They also provide the basis for a new model to study the pathogenesis of trauma‐induced HO. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:183–188, 2014.
Evaluation of total phenolics, flavonoids and antioxidant activity of 18 Korean onion cultivars: a comparative study
Authors: Sharma Kavita , Assefa Awraris D , Kim Seol , Ko Eun Young , Lee Eul Tai , Park Se Won
Published: October 2013

BACKGROUND

Onion is undoubtedly one of the major sources of flavonoids. However, there exists a varietal difference in composition, concentration and beneficial activities of onion, on the basis of cultivars, day length sensitivity/ripening and types. To characterise such differences, 18 onion cultivars from Korean were evaluated for their total phenolics, flavonoids and antioxidant activity. Simultaneous quantification of quercetin, quercetin‐3,4′‐O‐diglucoside, quercetin‐4′‐O‐monoglucoside and isorhamnetin‐3‐glucoside was made in methanol and 75% ethanol.

RESULTS

Total phenolic content was examined spectrophotometrically with the Folin–Ciocalteu phenol reagent and total antioxidant activity were studied by the ferric reducing antioxidant power (FRAP) and diphenyl picryl hydrazyl (DPPH) methods. The cultivar ‘Sunpower’ showed the highest level of total phenolics [5016 ± 30.0 µg gallic acid equivalents g−1 dry weight (DW)] and flavonoids (2873.95 ± 60.01 µg Q g−1 DW) among the 18 cultivars in methanol. However, there were fewer total phenolics and flavonoids in ethanol extracts. The antioxidant activity for cultivar Sunpower was highest in ethanol extracts 24.12 ± 1.00 and 16.13 ± 0.35 µmol L−1 Trolox equivalents g−1 DW with FRAP and DPPH, respectively.

CONCLUSION

Among the 18 cultivars, Sunpower is the most promising in terms of total phenolics, total flavonoids and antioxidant activity. Our results suggest that day length sensitivity/ripening among the cultivars do not play any significant role for high values of total phenolics, flavonoids and antioxidant activity. © 2013 Society of Chemical Industry
Single and fused transgenic Bacillus thuringiensis rice alter the species‐specific responses of non‐target planthoppers to elevated carbon dioxide and temperature
Authors: Wan Guijun , Dang Zhihao , Wu Gang , Parajulee Megha N , Ge Feng , Chen Fajun
Published: October 2013

BACKGROUND

The approval of transgenic Bacillus thuringiensis (Bt) rice by China was momentous for biotech crops, although it has yet to be approved for commercial production. Non‐target pest problems in rice paddies, such as the three ecologically similar species of planthoppers Nilaparvata lugens, Laodelphax striatellus and Sogatella furcifera, could become increasingly serious under global climate change. Fused (Cry1Ab/Cry1Ac) and single (Cry1Ab) transgenic Bt rice were evaluated for effects on species‐specific responses of planthoppers to elevated carbon dioxide (CO2) and temperature.

RESULTS

Transgenic Bt rice lines significantly modified species‐specific responses of the planthoppers to elevated CO2 and temperature. High temperature appears to favour outbreaks of S. furcifera relative to N. lugens and L. striatellus when feeding upon fused transgenic Bt rice, especially at elevated CO2. Elevated CO2 at high temperature appears to be a factor reducing S. furcifera occurrence when feeding upon single transgenic Bt rice.

CONCLUSION

Different types of transgenic Bt rice alter the species‐specific responses of non‐target planthoppers to elevated CO2 and temperature. Compared with their non‐transgenic parental lines, the single transgenic Bt rice shows better performance in controlling the non‐target planthopper S. furcifera by comparison with the fused transgenic Bt rice under elevated CO2 and temperature. It is suggested that multitypes of transgenic Bt rice be used in the field simultaneously in order to take advantage of high transgenic diversity for optimal performance against all pests in paddy fields. © 2013 Society of Chemical Industry
Youth advisory structures: Listening to young people to support quality youth services
Authors: Roholt Ross VeLure , Mueller Megan
Published: October 2013

Creating structures to include young people's opinions and advice has been recognized as important for high‐quality youth programs and services. Recent scholarship has begun to learn that most of these efforts are often symbolic rather than substantive. While continually advocated for, the practice is not widespread or well done. Using data from a statewide study of youth advisory structures and a case study of one advisory structure used within a municipal parks and recreation center, this article describes what both of these teach about creating substantive, meaningful, and useful youth advisory structure for program and organization development.
Electronic Structure and Magnetic Properties of Chromium Chalcogenides and Pnictides with NiAs Structure
Authors: Polesya Svitlana , Kuhn Gerhard , Benea Diana , Mankovsky Sergiy , Ebert Hubert
Published: October 2013

The structural as well as electronic and magnetic properties of chromium chalcogenides and pnictides with NiAs structure were studied using the Korringa‐Kohn‐Rostoker (KKR) band structure method. The magnetic properties at finite temperature were investigated by means of Monte Carlo simulations on the basis of a classical Heisenberg Hamiltonian and the exchange coupling parameters calculated from first principles. Combination of ab initio electronic structure calculations with Monte Carlo simulations allowed to investigate both the ground state magnetic properties as well as the finite‐temperature properties. In the case of stoichiometric systems, these calculations allowed to explain the origin of magnetic structures in this system as observed experimentally. In case of non‐stoichiometric Cr‐(Te, Se) alloys the origin of finite‐temperature spin‐glass and cluster‐glass behaviors was clarified. In all cases a reasonable agreement with the experiment was obtained for the value of the critical temperature.
Educational and Clinical Impact of Advanced Trauma Life Support (ATLS) Courses: A Systematic Review
Authors: Mohammad Alshafi , Branicki Frank , Abu‐Zidan Fikri M.
Published: October 2013

Background

We aimed to systematically review the literature on the educational impact of Advanced Trauma Life Support (ATLS) courses and their effects on death rates of multiple trauma patients.

Methods

All Medline, Pubmed, and the Cochrane Library English articles on the educational impact of ATLS courses and their effects on trauma mortality for the period 1966–2012 were studied. All original articles written in English were included. Surveys, reviews, editorials/letters, and other trauma courses or models different from the ATLS course were excluded. Articles were critically evaluated regarding study research design, statistical analysis, outcome, and quality and level of evidence.

Results

A total of 384 articles were found in the search. Of these, 104 relevant articles were read; 23 met the selection criteria and were critically analyzed. Ten original articles reported studies on the impact of ATLS on cognitive and clinical skills, six articles addressed the attrition of skills gained through ATLS training, and seven articles addressed the effects of ATLS on trauma mortality. There is level I evidence that ATLS significantly improves the knowledge of participants managing multiple trauma patients, their clinical skills, and their organization and priority approaches. There is level II–1 evidence that knowledge and skills gained through ATLS participation decline after 6 months, with a maximum decline after 2 years. Organization and priority skills, however, are kept for up to 8 years following ATLS. Strong evidence showing that ATLS training reduces morbidity and mortality in trauma patients is still lacking.

Conclusions

It is highly recommended that ATLS courses should be taught for all doctors who are involved in the management of multiple trauma patients. Future studies are required to properly evaluate the impact of ATLS training on trauma death rates and disability.
Latin American Attitudes toward Women in Politics: The Influence of Elite Cues, Female Advancement, and Individual Characteristics
Authors: MORGAN JANA , BUICE MELISSA
Published: October 2013

This article outlines three theoretical arguments—socialization, status discontent, and elite cues—that generate competing predictions about the way context shapes gender attitudes. Using hierarchical analysis, we assess the power of these arguments in Latin America, a region that manifests considerable variation on our central explanatory variables and thus offers important theoretical leverage. We find men's gender attitudes to be highly contingent on elite cues and susceptible to backlash effects in response to women's economic advancement. Also, where women lack national representation, distrust of government promotes support for female leadership as an alternative to the discredited (male) establishment. The analysis supports existing individual-level explanations of gender attitudes and demonstrates a connection between diffuse democratic values and gender egalitarianism. The findings suggest that recent advances for female politicians in Latin America may be susceptible to reversal, and they illuminate strategies for strengthening women's equality in the region.
Is there a change in the epidemiology of nasal fractures in females in the UK?
Authors: Trinidade A , Buchanan M A , Farboud A , Andreou Z , Ewart S , Mochloulis G , Kothari P , Frosh A C , Vlastarakos P V
Published: October 2013

Objective:

To determine whether there is a change in the epidemiology of nasal fractures in females in the UK, and the potential contribution of the ‘ladette’ culture.

Methods:

This paper reports a multi-centre retrospective study. Operating theatre data for all females who underwent manipulation of nasal fractures under anaesthesia between 2002 and 2009 were analysed. In addition, the case notes of all females presenting with nasal fractures over a five-year period (2004–2009) were retrospectively reviewed and the cited cause of the fracture was noted.

Results:

From 2002 to 2009, there was an 825 per cent increase in nasal fractures in women aged 13–20 years. Almost one-quarter of all nasal fractures in one centre was attributed to non-domestic violence. The highest incidence of nasal fractures (67 per cent) was amongst white British females.

Conclusion:

There is an increasing trend in the number of women sustaining nasal fractures in the UK. The cause may be multi-factorial, but could be partially attributed to a rise in ladette culture. Further research on the role of alcohol consumption in this phenomenon is needed.
Neck lump clinics: is on-site assessment of fine needle aspirate diagnostic adequacy cost-effective?
Authors: Burgess C , Dias L , Maughan E , Moorthy R
Published: October 2013

Objectives:

To establish the diagnostic adequacy of ultrasound-guided fine needle aspiration cytology samples at the East Berkshire neck lump clinic, and to perform a cost-benefit analysis related to the hypothetical addition of an on-site cytology technician (required to review fine needle aspiration specimen adequacy).

Method:

The adequacy of all ultrasound-guided fine needle aspiration procedures was reviewed from 1 January to 30 June 2011. These results were used in the cost-benefit analysis related to on-site cytology assessment.

Results:

Of the 307 ultrasound-guided fine needle aspiration cytology procedures performed over 6 months, 67 (22 per cent) were reported to be non-diagnostic. Operator experience was found to correlate significantly with diagnostic adequacy (p < 0.001). Only 5 per cent of all fine needle aspirations were initially non-diagnostic but diagnostic on repeat sampling. This suggests that the financial and time costs of on-site fine needle aspirate adequacy assessment would outweigh any benefit.

Conclusion:

In this series, the experience of individuals performing fine needle aspirations was the most important factor related to adequacy.
Change of state verbs and result state adjectives in Mandarin Chinese
Authors: THAM SHIAO WEI
Published: October 2013

This paper investigates the derivational relationship between adjectives and verbs in Mandarin Chinese describing related state, change of state (COS) and caused COS meanings. Such paradigms have been observed in various languages to fall into two categories: One in which a word naming a property concept state constitutes the derivational base for the related COS verbs, and another in which a COS verb forms the basis from which the stative word – a ‘result state’ predicate – is derived. I show that in Mandarin, the distinction between morphological paradigms based on property-concept words versus eventive verbs is also found, but the actual derivational relations between verbs and adjectives are influenced by language-particular morphological properties of Mandarin. Specifically, I argue that a gradable property concept adjective systematically alternates to a related COS verb. This alternation, which can be tapped by degree modification and negation contexts, distinguishes adjectives from stative verbs, which do not have consistent COS counterparts, and from underived intransitive COS verbs, which do not have systematic stative counterparts. That is, I show that COS verbs do not lend themselves to the systematic derivation of result state adjectives. Rather, I argue that result state adjectives in Mandarin arise from conceptual-pragmatic factors: The nominal modified by such a result state adjective should be understood as describing a culturally or contextually salient class of entities.
A Triangle Matching Algorithm for Gravity-aided Navigation for Underwater Vehicles
Authors: Yang Zhenli , Zhu Zhuangsheng , Zhao Weigao
Published: October 2013

In this paper, a triangle matching algorithm using local gravity field maps is proposed to bound the drift errors inherent in Strapdown Inertial Navigation Systems (SINS) in gravity-aided navigation. This triangle matching algorithm has two main stages, the first is the initial matching stage, which has a coarse phase and a fine phase to address the large unknown initial errors made by INS, and the other is the tracking matching stage, which mainly aims at tracking the matching solution with the vehicle running in real time. Simulations were carried out using data for the Bohai Sea and South China Sea areas, to assess the effects of different initial errors on the matching solutions. Finally some experiments were carried out to evaluate the proposed algorithm. The results show that the triangle matching algorithm has some compelling advantages, such as a capability to address the large unknown initial errors made by INS, and good real-time quality of matching the gravity measurements with the local gravity maps.
A NOTE ON THE EXISTENCE AND UNIQUENESS OF STATIONARY MONETARY EQUILIBRIUM IN A STOCHASTIC OLG MODEL
Authors: Ohtaki Eisei
Published: October 2013

This paper directly shows the equivalence between the existence of stationary monetary equilibrium and the conditional Pareto suboptimality of the initial endowment in a stochastic overlapping generations model. Especially, it gives short and constructive proofs for existence and uniqueness.
Results on the survival of cryptobiotic cyanobacteria samples after exposure to Mars-like environmental conditions
Authors: de Vera J. -P. , Dulai S. , Kereszturi A. , Koncz L. , Lorek A. , Mohlmann D. , Marschall M. , Pocs T.
Published: October 2013

Tests on cyanobacteria communities embedded in cryptobiotic crusts collected in hot and cold deserts on Earth were performed under Mars-like conditions. The simulations were realized as a survey, to find the best samples for future research. During the tests organisms have to resist Mars-like conditions such as atmospheric composition, pressure, variable humidity (saturated and dry conditions) and partly strong UV irradiation. Organisms were tested within their original habitat inside the crust. Nearly half of the cryptobiotic samples from various sites showed survival of a substantial part of their coexisting organisms. The survival in general depended more on the nature of the original habitat and type of the sample than on the different conditions they were exposed to. The best survival was observed in samples from United Arab Emirates (Jebel Ali, 25 km SW of Dubai town) and from Western Australia (near the South edge of Lake Barley), by taxa: Tolypothrix byssoidea, Gloeocapsopsis pleurocapsoides, Nostoc microscopicum, Leptolyngbya or Symploca sp. At both places in salty desert areas members of the Chenopodiaceae family dominated among the higher plants and in the cryptobiotic crust cyanobacterial taxa Tolypothrix was dominant. These organisms were all living in salty locations with dry conditions most of the year. Among them Tolypothrix, Gloeocapsopsis and Symploca sp. were tested in Mars simulation chambers for the first time. The results suggest that extremophiles should be tested with taken into account the context of their original microenvironment, and also the importance to analyse communities of microbes beside single organisms.
Kummer covers and braid monodromy
Authors: Artal Bartolo Enrique , Cogolludo-Agustín José Ignacio , Ortigas-Galindo Jorge
Published: October 2013

In this work, we describe a method to construct the generic braid monodromy of the preimage of a curve by a Kummer cover. This method is interesting since it combines two techniques, namely, the construction of a highly non-generic braid monodromy and a systematic method to go from a non-generic to a generic braid monodromy. The latter process, calledgenerification, is independent from Kummer covers, and it can be applied in more general circumstances since non-generic braid monodromies appear more naturally and are oftentimes much easier to compute. Explicit examples are computed using these techniques.
Chemotherapy-mediated p53-dependent DNA damage response in clear cell renal cell carcinoma: role of the mTORC1/2 and hypoxia-inducible factor pathways
Authors: Selvarajah J , Nathawat K , Moumen A , Ashcroft M , Carroll V A
Published: October 2013

The DNA-damaging agent camptothecin (CPT) and its analogs demonstrate clinical utility for the treatment of advanced solid tumors, and CPT-based nanopharmaceuticals are currently in clinical trials for advanced kidney cancer; however, little is known regarding the effects of CPT on hypoxia-inducible factor-2α (HIF-2α) accumulation and activity in clear cell renal cell carcinoma (ccRCC). Here we assessed the effects of CPT on the HIF/p53 pathway. CPT demonstrated striking inhibition of both HIF-1α and HIF-2α accumulation in von Hippel–Lindau (VHL)-defective ccRCC cells, but surprisingly failed to inhibit protein levels of HIF-2α-dependent target genes (VEGF, PAI-1, ET-1, cyclin D1). Instead, CPT induced DNA damage-dependent apoptosis that was augmented in the presence of pVHL. Further analysis revealed CPT regulated endothelin-1 (ET-1) in a p53-dependent manner: CPT increased ET-1 mRNA abundance in VHL-defective ccRCC cell lines that was significantly augmented in their VHL-expressing counterparts that displayed increased phosphorylation and accumulation of p53; p53 siRNA suppressed CPT-induced increase in ET-1 mRNA, as did an inhibitor of ataxia telangiectasia mutated (ATM) signaling, suggesting a role for ATM-dependent phosphorylation of p53 in the induction of ET-1. Finally, we demonstrate that p53 phosphorylation and accumulation is partially dependent on mTOR activity in ccRCC. Consistent with this result, pharmacological inhibition of mTORC1/2 kinase inhibited CPT-mediated ET-1 upregulation, and p53-dependent responses in ccRCC. Collectively, these data provide mechanistic insight into the action of CPT in ccRCC, identify ET-1 as a p53-regulated gene and demonstrate a requirement of mTOR for p53-mediated responses in this tumor type.
Fish gut microbiota analysis differentiates physiology and behavior of invasive Asian carp and indigenous American fish
Authors: Ye Lin , Amberg Jon , Chapman Duane , Gaikowski Mark , Liu Wen-Tso
Published: October 2013

Gut microbiota of invasive Asian silver carp (SVCP) and indigenous planktivorous gizzard shad (GZSD) in Mississippi river basin were compared using 16S rRNA gene pyrosequencing. Analysis of more than 440 000 quality-filtered sequences obtained from the foregut and hindgut of GZSD and SVCP revealed high microbial diversity in these samples. GZSD hindgut (GZSD_H) samples (n=23) with >7000 operational taxonomy units (OTUs) exhibited the highest alpha-diversity indices followed by SVCP foregut (n=15), GZSD foregut (n=9) and SVCP hindgut (SVCP_H) (n=24). UniFrac distance-based non-metric multidimensional scaling (NMDS) analysis showed that the microbiota of GZSD_H and SVCP_H were clearly separated into two clusters: samples in the GZSD cluster were observed to vary by sampling location and samples in the SVCP cluster by sampling date. NMDS further revealed distinct microbial community between foregut to hindgut for individual GZSD and SVCP. Cyanobacteria, Proteobacteria, Actinobacteria and Bacteroidetes were detected as the predominant phyla regardless of fish or gut type. The high abundance of Cyanobacteria observed was possibly supported by their role as the fish’s major food source. Furthermore, unique and shared OTUs and OTUs in each gut type were identified, three OTUs from the order Bacteroidales, the genus Bacillariophyta and the genus Clostridium were found significantly more abundant in GZSD_H (14.9–22.8%) than in SVCP_H (0.13–4.1%) samples. These differences were presumably caused by the differences in the type of food sources including bacteria ingested, the gut morphology and digestion, and the physiological behavior between GZSD and SVCP.
Integration of In Vitro Binding Mechanism Into the Semiphysiologically Based Pharmacokinetic Interaction Model Between Ketoconazole and Midazolam
Authors: Quinney Sara K. , Knopp Shawn , Chang Chien , Hall Stephen D. , Li Lang
Published: October 2013

In vitro screening for drug–drug interactions is an integral component of drug development, with larger emphasis now placed on the use of in vitro parameters to predict clinical inhibition. However, large variability exists in Ki reported for ketoconazole with midazolam, a model inhibitor–substrate pair for CYP3A. We reviewed the literature and extracted Ki for ketoconazole as measured by the inhibition of hydroxymidazolam formation in human liver microsomes. The superset of data collected was analyzed for the impact of microsomal binding, using Langmuir and phase equilibrium binding models, and fitted to various inhibition models: competitive, noncompetitive, and mixed. A mixed inhibition model with binding corrected by an independent binding model was best able to fit the data (Kic = 19.2 nmol/l and Kin = 39.8 nmol/l) and to predict clinical effect of ketoconazole on midazolam area under the concentration–time curve. The variability of reported Ki may partially be explained by microsomal binding and choice of inhibition model.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e75; doi:10.1038/psp.2013.50; published online 11 September 2013
Mechanistic Vs. Empirical Network Models of Drug Action
Authors: Birtwistle MR , Mager DE , Gallo JM
Published: October 2013

Declining success rates coupled with increased costs is leading to an inevitable breaking point in the drug development pipeline. Can we avoid it by incorporating the vast mechanistic understanding of drug action? A recent review highlights this dilemma and proposes “quantitative logic gate” modeling as a solution.1 The goal of this commentary is to contrast this approach with mechanistic biochemical network models, which, although alluded to by Kiruoac and Onsum, requires a closer analysis.

CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e72; doi:10.1038/psp.2013.51; advance online publication 6 September 2013
Response in electrostatic analyzers due to backscattered electrons: Case study analysis with the Juno Jovian Auroral Distribution Experiment-Electron instrument
Authors: Clark G. , Allegrini F. , Randol B. M. , McComas D. J. , Louarn P.
Published: October 2013

In this study, we introduce a model to characterize electron scattering in an electrostatic analyzer. We show that electrons between 0.5 and 30 keV scatter from internal surfaces to produce a response up to ∼20% of the ideal, unscattered response. We compare our model results to laboratory data from the Jovian Auroral Distribution Experiment-Electron sensor onboard the NASA Juno mission. Our model reproduces the measured energy-angle response of the instrument well. Understanding and quantifying this scattering process is beneficial to the analysis of scientific data as well as future instrument optimization.
Analytic evaluation of the dipole Hessian matrix in coupled-cluster theory
Authors: Jagau Thomas-C. , Gauss Jürgen , Ruud Kenneth
Published: October 2013

The general theory required for the calculation of analytic third energy derivatives at the coupled-cluster level of theory is presented and connected to preceding special formulations for hyperpolarizabilities and polarizability gradients. Based on our theory, we have implemented a scheme for calculating the dipole Hessian matrix in a fully analytical manner within the coupled-cluster singles and doubles approximation. The dipole Hessian matrix is the second geometrical derivative of the dipole moment and thus a third derivative of the energy. It plays a crucial role in IR spectroscopy when taking into account anharmonic effects and is also essential for computing vibrational corrections to dipole moments. The superior accuracy of the analytic evaluation of third energy derivatives as compared to numerical differentiation schemes is demonstrated in some pilot calculations.
A comparison of the carrier density at the surface of quantum wells for different crystal orientations of silicon, gallium arsenide, and indium arsenide
Authors: Hatcher Ryan , Bowen Chris
Published: October 2013

We report the carrier densities at the surface of single-crystal quantum wells as a function of material, orientation, and well width. We include wells constructed from silicon, gallium arsenide, and indium arsenide with three crystal orientations, (100), (110), and (111), included for each material. We find that the Δ2 states in a silicon (100) quantum well have the smallest density near the surface of the slab. Inspection of the planar average of the carrier densities reveals a characteristic shape that depends on the material and orientation, which leads to a varying degree of suppression or enhancement of the density near the surface. The physics responsible for the suppression or enhancement of the density near the surface can be traced to a constraint imposed by the symmetry of quantum well wavefunction on the phases of the bulk Bloch states of the crystal from which it can be constructed.
Propagation speed of rotation signals for field lines undergoing magnetic reconnection
Authors: Lapenta Giovanni , Goldman Martin , Newman David , Markidis Stefano
Published: October 2013

Reconnection is associated with two bending of the magnetic field lines. Considering the usual plane of a 2D reconnection simulation, the first bending is in-plane and produces the needed topological changes by bringing oppositely directed filed lines in proximity. The second is typical of fast reconnection and is out of plane, leading to the formation of the Hall magnetic field. This second rotation has recently been observed to proceed at superAlfvénic speeds and to carry substantial energy fluxes (Shay et al., Phys. Rev. Lett. 107, 065001 (2011)). We revisit these rotations with a new diagnostics based on dispersing a multitude of virtual probes into a kinetic simulation, akin the approach of multi spacecraft missions. The results of the new diagnostics are compared with the theory of characteristics applied to the two fluid model. The comparison of virtual probes and the method of characteristics confirm the findings relative to the out of plane rotation and uncover the existence of two families of characteristics. Both are observed in the simulation. The early stage of reconnection develops on the slower compressional branch and the later faster phase develops on the faster torsional branch. The superAlfvénic signal is only relevant in the second phase.
Dynamical coupling and negative differential resistance from interactions across the molecule-electrode interface in molecular junctions
Authors: Dubi Yonatan
Published: October 2013

Negative differential resistance – a decrease in current with increasing bias voltage – is a counter-intuitive effect that is observed in various molecular junctions. Here, we present a novel mechanism that may be responsible for such an effect, based on strong Coulomb interaction between electrons in the molecule and electrons on the atoms closest to the molecule. The Coulomb interaction induces electron-hole binding across the molecule-electrode interface, resulting in a renormalized and enhanced molecule-electrode coupling. Using a self-consistent non-equilibrium Green's function approach, we show that the effective coupling is non-monotonic in bias voltage, leading to negative differential resistance. The model is in accord with recent experimental observations that showed a correlation between the negative differential resistance and the coupling strength. We provide detailed suggestions for experimental tests which may help to shed light on the origin of the negative differential resistance. Finally, we demonstrate that the interface Coulomb interaction affects not only the I-V curves but also the thermoelectric properties of molecular junctions.
Computation of the expansion parameters of femto-waveguides using a two dimensional μ-Raman map and guided modes
Authors: Tejerina M. R. , Torchia G. A.
Published: October 2013

The expansion parameters of a numerical elastic model that simulates femtosecond laser-material interactions are computed. To achieve this, two dimensional micro-Raman mapping, an elastic-optic finite element model, and the experimental intensity profile of the guided modes were used. To complement this data, the Raman deformation potential constants of the lithium niobate A1(TO4) phonon were obtained and compared with those reported in previous works.
Large infrared absorptance of bimaterial microcantilevers based on silicon high contrast grating
Authors: Kwon Beomjin , Seong Myunghoon , Liu Jui-Nung , Rosenberger Matthew R. , Schulmerich Matthew V. , Bhargava Rohit , Cunningham Brian T. , King William P.
Published: October 2013

Manufacturing sensors for the mid-IR spectral region (3–11 μm) are especially challenging given the large spectral bandwidth, lack of convenient material properties, and need for sensitivity due to weak sources. Here, we present bimaterial microcantilevers based on silicon high contrast grating (HCG) as alternatives. The grating integrated into the cantilevers leverages the high refractive index contrast between the silicon and its surrounding medium, air. The cantilevers with HCG exhibit larger active spectral range and absorptance in mid-IR as compared to cantilevers without HCG. We design and fabricate two types of HCG bimaterial cantilevers such that the HCG resonance modes occur in mid-IR spectral region. Based on the measurements using a Fourier transform infrared (FTIR) microspectrometer, we show that the HCG cantilevers have 3–4X wider total IR absorptance bandwidths and 30% larger absorptance peak amplitude than the cantilever without HCG, over the 3–11 μm wavelength region. Based on the enhanced IR absorptance, HCG cantilevers show 13–47X greater responsivity than the cantilever without HCG. Finally, we demonstrate that the enhanced IR sensitivity of the HCG cantilever enables transmission IR spectroscopy with a Michelson interferometer. The HCG cantilever shows comparable signal to noise ratio to a low-end commercial FTIR system and exhibits a linear response to incident IR power.
The metal interlayer in the charge generation layer of tandem organic light-emitting diodes
Authors: Lee Yu-Hao , Lin Ming-Wei , Wen Ten-Chin , Guo Tzung-Fang
Published: October 2013

This work studies the interface in the charge generation layer (CGL), consisting of aluminum (Al) doped in poly(ethylene glycol) dimethyl ether as an n-type layer and 2, 3, 5, 6-tetrafluoro-7, 7, 8, 8-tetracyanoquinodimethane (F4-TCNQ) doped in N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4-4′-diamine as an p-type layer, in tandem organic light-emitting diodes (OLEDs). Introducing a thin high work function metal interlayer (e.g., Ag or Au) effectively improves the transport and inhibits the accumulation of charges in the CGL, which markedly reduces the operating voltage and enhances the efficiency of tandem OLEDs. We attribute that the high density of surface states on metal clusters (interlayer) reduce the junction barrier to facilitate the transport of carriers through CGL. Experimental results show enhancements of tandem OLEDs by an additional metal interlayer as follows: luminous efficiency increases from 37.2 to 51.4 cd A−1, the light turn-on voltage decreases from 9.2 to 6.6 V, and luminescence at 10 mA cm−2 increases from 3712 to 5211 cd m−2.
Note: Tunable overlapping half-ring resonator
Authors: Torun H. , Sadeghzadeh S. , Yalcinkaya A. D.
Published: October 2013

A unique tunable microwave resonator with a pair of half-rings is introduced and validated by experimental data. The capacitive gap between the overlapping areas can be controlled accurately using a magnetic actuator for tunability. The design geometry is scalable to cover different bands of electromagnetic spectrum. Transmission characteristics of the resonators have been modeled using finite-element analysis and have been measured. The experimental results indicate the resonant frequency can be controlled with a resolution of a few MHz in a tuning range of 38%. The resonator exhibits sharp transmission dips within the tuning range with measured quality factors larger than 2500.
Impact of Mg concentration on energy-band-depth profile of Mg-doped InN epilayers analyzed by hard X-ray photoelectron spectroscopy
Authors: Imura M. , Tsuda S. , Nagata T. , Takeda H. , Liao M. Y. , Yang A. L. , Yamashita Y. , Yoshikawa H. , Koide Y. , Kobayashi K. , Yamaguchi T. , Kaneko M. , Uematsu N. , Wang K. , Araki T. , Nanishi Y.
Published: October 2013

The electronic structures of Mg-doped InN (Mg-InN) epilayers with the Mg concentration, [Mg], ranging from 1 × 1019 to 5 × 1019 cm−3 were systematically investigated by soft and hard X-ray photoelectron spectroscopies. The angle-resolved results on the core-level and valence band photoelectron spectra as a function of [Mg] revealed that the energy band of Mg-InN showed downward bending due to the n+ surface electron accumulation and p type layers formed in the bulk. With an increase in [Mg], the energy-band changed from monotonic to two-step n+p homojunction structures. The oxygen concentration rapidly increased at the middle-bulk region (∼4.5 to ∼7.5 nm) from the surface, which was one of the reasons of the transformation of two-step energy band.
Thermally induced evolution of hydrogenated amorphous carbon
Authors: Mangolini Filippo , Rose Franck , Hilbert James , Carpick Robert W.
Published: October 2013

The thermally induced structural evolution of hydrogenated amorphous carbon (a-C:H) films was investigated in situ by X-ray photoelectron spectroscopy for annealing temperatures up to 500 °C. A model for the conversion of sp3- to sp2-hybridized carbon in a-C:H vs. temperature and time was developed and applied to determine the ranges of activation energies for the thermally activated processes occurring. The energies are consistent with ordering and clustering of sp2 carbon, scission of sp3 carbon-hydrogen bonds and formation of sp2 carbon, and direct transformation of sp3- to sp2-hybridized carbon.
Quantum Bohm correction to polarization spectrum of graphene
Authors: Akbari-Moghanjoughi M.
Published: October 2013

In this paper, by using a quantum hydrodynamic plasma model which incorporates the important quantum statistical pressure and electron diffraction force, we present the corrected plasmon dispersion relation for graphene which includes a k4 quantum term arising from the collective electron density wave interference effects. This correction may well describe the shortcoming of the previous results based on the classical hydrodynamics and confirms that the quantum hydrodynamic model may be as effective as the random phase approximation in successful description of the collective density excitations in quantum plasmas. It is clearly observed that the quantum correction due to the collective interaction of electron waves gives rise to significant contribution in the dispersion behavior of the collective plasmon density waves in a wide range of wavelength, as a fundamental property of the monolayer atom-thick graphene. It is revealed that the plasmon density-perturbation linear phase-speed in graphene possesses some universal minimum characteristic value, in the absence of an external magnetic field. It is further remarked that such correction also has important effect on the dielectric function, hence on the impurity screening, in graphene.
Triple-channel terahertz filter based on mode coupling of cavities resonance system
Authors: Xu JiaMing , Chen Lin , Zang XiaoFei , Cai Bin , Peng Yan , Zhu YiMing
Published: October 2013

A high-quality triple-channel terahertz filter based on silicon multi-cavity resonant system has been experimentally investigated by using backward wave oscillator. Theoretical methods have been employed to analyze physical origin of the resonances and the transmission properties. We find that the lower transmission peak comes from the Fabry-Perot resonance in the side two thick cavities and the two higher peaks are caused by the symmetrically and asymmetrically coupling of the two thin cavities in the middle. The resonant peaks show blue shift by increasing the incident angle, which are attributed to the change of effective refractive indices.
Spectroscopic and Modelling Analysis on the Interaction of 3'-Azidodaunorubicin Semicarbazone with ctDNA
Authors: Cui Fengling , Jin Jianhua , Niu Xiaoqing , Liu Qingfeng , Zhang Guisheng
Published: October 2013

The synthesis and characterisation of a new anthracycline, 3′-azidodaunorubicin semicarbazone (ADNRS) is reported. The interaction between ADNRS and calf thymus DNA (ctDNA) was investigated by absorption and fluorescence spectroscopy in combination with melting temperature (Tm) curves and molecular modelling in physiological buffer (pH 7.4). Evidence indicates that ADNRS binds in the groove of ctDNA and the fluorescence quenching mechanism is a static quenching type. Calculated thermodynamic parameters show that hydrophobic interactions may play a predominant role in the binding. Furthermore, molecular modelling results corroborate the spectroscopic investigations.