bluuebunny/crossref_metadata_2025 huggingface dataset:
The Colibactin Genotoxin Generates DNA Interstrand Cross-Links in Infected Cells
Authors: Bossuet-Greif Nadège , Vignard Julien , Taieb Frédéric , Mirey Gladys , Dubois Damien , Petit Claude , Oswald Eric , Nougayrède Jean-Philippe
Published: March 2018

Colibactins are hybrid polyketide-nonribosomal peptides produced by
Escherichia coli
,
Klebsiella pneumoniae
, and other
Enterobacteriaceae
harboring the
pks
genomic island. These genotoxic metabolites are produced by
pks
-encoded peptide-polyketide synthases as inactive prodrugs called precolibactins, which are then converted to colibactins by deacylation for DNA-damaging effects. Colibactins are bona fide virulence factors and are suspected of promoting colorectal carcinogenesis when produced by intestinal
E. coli
. Natural active colibactins have not been isolated, and how they induce DNA damage in the eukaryotic host cell is poorly characterized. Here, we show that DNA strands are cross-linked covalently when exposed to enterobacteria producing colibactins. DNA cross-linking is abrogated in a
clbP
mutant unable to deacetylate precolibactins or by adding the colibactin self-resistance protein ClbS, confirming the involvement of the mature forms of colibactins. A similar DNA-damaging mechanism is observed
in cellulo
, where interstrand cross-links are detected in the genomic DNA of cultured human cells exposed to colibactin-producing bacteria. The intoxicated cells exhibit replication stress, activation of ataxia-telangiectasia and Rad3-related kinase (ATR), and recruitment of the DNA cross-link repair Fanconi anemia protein D2 (FANCD2) protein. In contrast, inhibition of ATR or knockdown of FANCD2 reduces the survival of cells exposed to colibactin-producing bacteria. These findings demonstrate that DNA interstrand cross-linking is the critical mechanism of colibactin-induced DNA damage in infected cells.

IMPORTANCE
Colorectal cancer is the third-most-common cause of cancer death. In addition to known risk factors such as high-fat diets and alcohol consumption, genotoxic intestinal
Escherichia coli
bacteria producing colibactin are proposed to play a role in colon cancer development. Here, by using transient infections with genotoxic
E. coli
, we showed that colibactins directly generate DNA cross-links
in cellulo
. Such lesions are converted into double-strand breaks during the repair response. DNA cross-links, akin to those induced by metabolites of alcohol and high-fat diets and by widely used anticancer drugs, are both severely mutagenic and profoundly cytotoxic lesions. This finding of a direct induction of DNA cross-links by a bacterium should facilitate delineating the role of
E. coli
in colon cancer and engineering new anticancer agents.
Targeting skeletal muscle tissue oxygenation (StO2) in adults with severe sepsis and septic shock: a randomised controlled trial (OTO-StS Study)
Authors: Nardi Olivier , Zavala Elizabeth , Martin Claude , Nanas Serafim , Scheeren Thomas , Polito Andrea , Borrat Xavi , Annane Djillali
Published: March 2018

Objective

Evaluation of the ratio of oxyhaemoglobin to total haemoglobin in skeletal muscle (StO2) using near-infrared spectroscopy may aid in the monitoring of patients with sepsis. This study assessed the benefits and risks of targeting StO2in adults with severe sepsis or septic shock.

Design

A European randomised controlled trial was performed on two parallel groups.

Setting

Five intensive care units (ICU) in France, Greece, Spain and Germany were used for the study.

Participants

A total of 103 adults with severe sepsis or septic shock on ICU admission were randomised (54 subjects in the experimental arm and 49 subjects in the control arm).

Interventions

Haemodynamic management using an algorithm that was adapted from the 2004 Surviving Sepsis Campaign guidelines with (experimental arm) or without (control arm) targeting an StO2value greater than 80% at a minimum of two different sites.

Outcomes

The primary outcome was a composite: 7-day all-cause mortality or worsening of organ function, defined as a positive difference in Sepsis-related Organ Failure Assessment (SOFA) score between day 7 and randomisation (ie, delta SOFA >0). Secondary endpoints: 30-day mortality, duration of mechanical ventilation and vasopressor therapy up to 30 days from randomisation.

Results

The study ended prematurely due to lack of funding after enrolment of 103/190 patients. Eighteen patients (33.3%) in the experimental arm and 14 (28.6%, P=0.67) in the control arm died or exhibited delta SOFA >0 on day 7. The mean number of days on mechanical ventilation was 12.2±10.6 in the experimental group and 7.6±7.9 in the control group (P=0.03). Thirty-one (57%) patients in the experimental arm and 14 (29%) patients in the control arm received red cells by day 7 (P=0.01).

Conclusion

Despite the limitation related to premature termination, this study provides no data to support the routine implementation of resuscitation protocols incorporating StO2>80% at two or more muscle sites as a target. StO2-guided therapy may be associated with prolonged use of mechanical ventilation and an increased number of red blood cell transfusions.

Trial registration number

NCT00167596; Results.
Association of prehypertension and hyperhomocysteinemia with subclinical atherosclerosis in asymptomatic Chinese: a cross-sectional study
Authors: Liu Bo , Chen Zhihao , Dong Xiaoqi , Qin Guangming
Published: March 2018

Objectives

Comorbid hypertension and hyperhomocysteinemia is an important risk factor for carotid atherosclerotic plaque formation. We put forward the hypothesis that the subjects with comorbid prehypertension and hyperhomocysteinemia also had an increased risk of subclinical atherosclerosis, using carotid intima–media thickness (CIMT) as the marker of the atherosclerotic process.

Methods

A total of 4102 asymptomatic Chinese subjects aged 18–60 years were divided into four groups according to blood pressure (BP) and homocysteine (HCY) level: the control group without prehypertension or hyperhomocysteinemia, isolated prehypertension group, simple hyperhomocysteinemia group and prehypertension with hyperhomocysteinemia group. Serum lipids, fasting blood glucose (FBG), HCY and CIMT were measured.

Results

There was significant difference in the positive rates of increased CIMT among four groups. Compared with the controls, the subjects in the other three groups had a higher risk of increased CIMT (isolated prehypertension group, OR 2.049, 95% CI 1.525 to 2.754; simple hyperhomocysteinemia group, OR 2.145, 95% CI 1.472 to 3.125; prehypertension and hyperhomocysteinemia group, OR 3.199, 95% CI 2.362 to 4.332). However, by multiple logistic regression analysis, only comorbid prehypertension and hyperhomocysteinemia was independently associated with increased CIMT (OR 1.485, 95% CI 1.047 to 2.108, P<0.05).

Conclusions

Comorbid prehypertension and hyperhomocysteinemia was an independent risk factor of subclinical atherosclerosis in asymptomatic Chinese, but isolated prehypertension or hyperhomocysteinemia was not. Therefore, combined intervention for prehypertension and hyperhomocysteinemia may contribute to decrease the incident of cardiovascular disease.
Effect of age and cone dimensions on cervical regeneration: an Italian multicentric prospective observational study
Authors: Ciavattini Andrea , Delli Carpini Giovanni , Moriconi Lorenzo , Clemente Nicolò , Montik Nina , De Vincenzo Rosa , Del Fabro Anna , Buttignol Monica , Ricci Caterina , Moro Francesca , Sopracordevole Francesco
Published: March 2018

Objectives

To evaluate cervical regeneration at 6 months following excisional treatment for high-grade cervical intraepithelial neoplasia (CIN), and to investigate the effect of cone dimensions, age of patients and technique of excision on the efficacy of the regeneration process.

Design

Prospective observational multicentric study.

Setting

Three tertiary care and research centres.

Participants

Among the 197 eligible women of childbearing age, older than 25 years of age, undergoing for the first time a loop electrosurgical excision procedure or carbon dioxide laser cervical excision for a high-grade CIN at the colposcopy-directed cervical punch biopsy, and with a final diagnosis of high-grade CIN, 165 completed the 6-month follow-up and were included in the analysis.

Primary outcome measures

The cervical length and volume regeneration (%) after 6 months from procedure were determined by three-dimensional ultrasound, and the correlation of regeneration with cone dimensions, age and excision technique was evaluated.

Results

The mean±SD cervical length regeneration at 6 months was 89.5%±6.3% and the mean±SD cervical volume regeneration was 86.3%±13.2%. At the multivariate analysis, a significant and independent inverse correlation between excised cone length and cervical regeneration emerged (r=−0.39, P<0.001). A significantly negative trend in length regeneration at 6 months from procedure with an increasing class of cone length was found (P<0.001). No significant association was found in relation with patient age at the time of procedure or with the technique of excision.

Conclusions

Cervical length regeneration at 6 months from excisional treatments is negatively affected by an increasing cone length but not from the age of the patient or the technique of excision. While still achieving equal clinical efficacy, it is crucial to contain cone dimensions, in order to favour a greater length regeneration, reducing the cervical harm and the potential future obstetric complications.
Improving driving advice provided to cardiology patients on discharge
Authors: Vusirikala Amoolya , Backhouse Mark , Schimansky Sarah
Published: March 2018

Certain cardiac conditions can limit patients’ ability to drive. It remains the doctors' responsibility to advise patients of any driving restrictions and is particularly important after certain diagnoses or procedures. We identified that the quality of documented advice was variable and frequently no written driving advice was recorded on discharge. It was apparent that there was a lack of awareness and knowledge of the current Driving and Vehicle Licensing Agency (DVLA) guidance among junior doctors.

We therefore designed a quality improvement project using Plan–Do–Study–Act (PDSA) methodology to improve the provision of driving advice on discharge from a cardiology ward by focusing on staff education. After collecting baseline data, we created a template with cardiology-specific DVLA advice. During the second PDSA cycle, we improved the electronic template and also introduced a hard copy on the ward. During the third PDSA cycle, we incorporated information on DVLA guidance in the specialty induction session. We also evaluated junior doctors’ confidence of providing driving advice before and after this intervention.

Baseline measurements showed that 10% (9/92) of all discharge summaries included driving advice. This improved to 49% (34/69) after the third PDSA cycle. Importantly, after receiving information on driving advice in the induction, junior doctors felt more confident in providing driving advice to cardiology patients on discharge. In conclusion, the provision of driving advice on discharge is an important element of patient safety. However, clinicians’ knowledge and awareness of current DVLA guidance is often limited. We demonstrated a significant increase in the provision of driving advice by introducing a standardised template.
Can first-year medical students acquire quality improvement knowledge prior to substantial clinical exposure? A mixed-methods evaluation of a pre-clerkship curriculum that uses education as the context for learning
Authors: Brown Allison , Nidumolu Aditya , Stanhope Alexandra , Koh Justin , Greenway Matthew , Grierson Lawrence
Published: March 2018

Background

Quality Improvement (QI) training for health professionals is essential to strengthen health systems. However, QI training during medical school is constrained by students’ lack of contextual understanding of the health system and an already saturated medical curriculum. The Program for Improvement in Medical Education (PRIME), an extracurricular offered at the Michael G. DeGroote School of Medicineat McMaster University (Hamilton, Canada), addresses these obstacles by having first-year medical students engage in QI by identifying opportunities for improvement within their own education.

Methods

A sequential explanatory mixed-methods approach, which combines insights derived from quantitative instruments and qualitative interview methods, was used to examine the impact of PRIME on first-year medical students and the use of QI in the context of education.

Results

The study reveals that participation in PRIME increases both knowledge of, and comfort with, fundamental QI concepts, even when applied to clinical scenarios. Participants felt that education provided a meaningful context to learn QI at this stage of their training, and were motivated to participate in future QI projects to drive real-world improvements in the health system.

Conclusions

Early exposure to QI principles that uses medical education as the context may be an effective intervention to foster QI competencies at an early stage and ultimately promote engagement in clinical QI. Moreover, PRIME also provides a mechanism to drive improvements in medical education. Future research is warranted to better understand the impact of education as a context for later engagement in clinical QI applications as well as the potential for QI methods to be translated directly into education.
Inclusive W boson QCD predictions and lepton charge asymmetry in proton–proton collisions at = 14 TeV
Authors: Dilsiz Kamuran , Tiras Emrah
Published: March 2018

Inclusive W ([Formula: see text]) boson QCD predictions and lepton charge asymmetry in proton–proton collisions at [Formula: see text] = 14 TeV is performed in this study. Total and fiducial cross section predictions are obtained up to next to next to leading order (NNLO) QCD corrections using Monte Carlo for FeMtobarn processes (MCFM) MC generator. To validate the predictions, a detailed comparison of NNLO QCD calculations with 8 TeV CMS results is performed. To discuss the advantage of the higher order QCD predictions on the scale uncertainty, a scale dependence study is presented based on the choice of renormalization (μR) and factorization (μF) scale variations. W boson – lepton charge asymmetry and differential cross section as a function of lepton pseudorapidity at [Formula: see text] = 14 TeV are further performed in 11 |η| regions.
Steady three-dimensional flows past hollow fiber membrane arrays – cross flow arrangement
Authors: Usta Mustafa , Morabito Michael , Alrehili Mohammed , Hakim Alaa , Oztekin Alparslan
Published: March 2018

Hollow fiber membrane (HFM) modules are among the most common separation devices employed in membrane separation applications. Three-dimensional steady-state computational fluid dynamics (CFD) simulations are carried out to study flow past hollow fiber membrane banks (HFMB). The current study investigates the effects of flow behavior on membrane performance during binary mixture separations. Carbon dioxide (CO2) removal from methane (CH4) is examined for various arrangements of HFMs in staggered and inline configurations. The common HFM module arrangement is the axial flow configuration. However, this work focuses on the radial cross-flow configuration. The HFM surface is a functional boundary where the suction rate and concentration of each species are coupled and are functions of the local partial pressures, the permeability, and the selectivity of the HFM. CFD simulations employed the turbulent k–ω shear stress transport (SST) model to study HFM performance for Reynolds numbers, 200 ≤ Re ≤ 1000. The efficiency of the inline and staggered arrangements in the separation module is evaluated by the coefficient of performance and the rate of mass flow per unit area of CO2 passing across the membrane surface. This work demonstrates that the module with staggered arrangement outperforms the module with the inline arrangement.
Control of glyphosate-resistant common ragweed in corn with preemergence herbicides
Authors: Soltani Nader , Brown Lynette , Sikkema Peter H.
Published: March 2018

Four field experiments were conducted during 2016 and 2017 to evaluate the efficacy of preemergence herbicides to control glyphosate-resistant common ragweed in corn. Dicamba, dicamba/atrazine, mesotrione + atrazine, isoxaflutole + atrazine, saflufenacil/dimethenamid-P, and S-metolachlor/mesotrione/bicyclopyrone/atrazine were the most efficacious herbicides, providing 94%–100% control of GR common ragweed and reducing density and biomass 98%–100%.
AAC Glenview sainfoin (Onobrychis viciifoila subsp. viciifolia)
Authors: Acharya S.N.
Published: March 2018

AAC Glenview sainfoin, tested as LRC 4342, was developed by the Agriculture and Agri-Food Canada (AAFC) Lethbridge Research and Development Centre, Lethbridge, Alberta. This cultivar was derived from parental clones selected for improved forage yield in mixed stands with alfalfa under grazing and regrowth after grazing. When grown under irrigated and rainfed conditions in western Canada, Glenview out yielded Nova (check) by 21% in pure stands over 37 location–years and 19% in mixed stands with alfalfa over 17 location–years. This cultivar flowers and matures about 8 d earlier than Nova and has slightly larger seed than Nova (24.7 g 1000 seeds−1 vs 20 g 1000 seeds−1). It can be grown for hay and pasture in pure stands but Glenview is well suited for mixed sainfoin–alfalfa stands. Breeder seed for the cultivar will be produced by AAFC and the multiplication and distribution rights were awarded to Monarch Feeders Ltd., Monarch, AB, Canada.
CO464 corn inbred line
Authors: Reid L.M. , Voloaca C. , Wu J. , Woldemariam T. , Jindal K.K. , Jindal M.M. , Zhu X.
Published: March 2018

CO464 is a short-season corn (Zea mays L.) inbred line with excellent combining ability with Iodent inbred testers as well as intermediate resistance to common rust, eyespot, common smut, and Fusarium stalk rot.
Criteria for a good catch: A conceptual framework to guide sourcing of sustainable salmon fisheries
Authors: Gayeski Nick , MacDuffee Misty , Stanford Jack A.
Published: March 2018

The identification of sustainably managed fisheries is problematic for marketers and consumers of Pacific salmon food products owing to lack of well-defined and robust criteria that take into account current ecosystem science of salmon. We present the rationale for an alternative conceptual framework for salmon management that supports the development of sustainable sourcing criteria. Our approach contrasts with current large-scale fisheries certification programs such as that of the Marine Stewardship Council (MSC) and general consumer recommendation services such as Monterey Bay Aquarium’s Seafood Watch (SFW) program. Our framework is based on the “place-based” character of salmon populations and recognition of fundamental aspects of salmon ecology, particularly the evolution of population life histories that are locally adapted to freshwater spawning and rearing habitats. We describe how this framework underpins development of science-based sourcing criteria and how it differs in important respects from the industrial approach that historically and currently is the basis for most salmon management. We conclude with a discussion of how the framework and its application may provide a model for redirecting salmon management, in general, towards a more science- and place-based approach and why that is likely to be sustainable in the long term in a way that most contemporary salmon management is not.
Deep Neural Architectures for Mapping Scalp to Intracranial EEG
Authors: Antoniades Andreas , Spyrou Loukianos , Martin-Lopez David , Valentin Antonio , Alarcon Gonzalo , Sanei Saeid , Took Clive Cheong
Published: March 2018

Data is often plagued by noise which encumbers machine learning of clinically useful biomarkers and electroencephalogram (EEG) data is no exemption. Intracranial EEG (iEEG) data enhances the training of deep learning models of the human brain, yet is often prohibitive due to the invasive recording process. A more convenient alternative is to record brain activity using scalp electrodes. However, the inherent noise associated with scalp EEG data often impedes the learning process of neural models, achieving substandard performance. Here, an ensemble deep learning architecture for nonlinearly mapping scalp to iEEG data is proposed. The proposed architecture exploits the information from a limited number of joint scalp-intracranial recording to establish a novel methodology for detecting the epileptic discharges from the sEEG of a general population of subjects. Statistical tests and qualitative analysis have revealed that the generated pseudo-intracranial data are highly correlated with the true intracranial data. This facilitated the detection of IEDs from the scalp recordings where such waveforms are not often visible. As a real-world clinical application, these pseudo-iEEGs are then used by a convolutional neural network for the automated classification of intracranial epileptic discharges (IEDs) and non-IED of trials in the context of epilepsy analysis. Although the aim of this work was to circumvent the unavailability of iEEG and the limitations of sEEG, we have achieved a classification accuracy of 68% an increase of 6% over the previously proposed linear regression mapping.
A recursion for counts of real curves in ℂℙ2n−1: Another proof
Authors: Georgieva Penka , Zinger Aleksey
Published: March 2018

In a recent paper, we obtained a WDVV-type relation for real genus 0 Gromov–Witten invariants with conjugate pairs of insertions; it specializes to a complete recursion in the case of odd-dimensional projective spaces. This paper provides another, more complex-geometric, proof of the latter. The main part of this approach readily extends to real symplectic manifolds with empty real locus, but not to the general case.
A class of C∗-algebraic locally compact quantum groupoids part I. Motivation and definition
Authors: Kahng Byung-Jay , Van Daele Alfons
Published: March 2018

In this series of papers, we develop the theory of a class of locally compact quantum groupoids, which is motivated by the purely algebraic notion of weak multiplier Hopf algebras. In this Part I, we provide motivation and formulate the definition in the [Formula: see text]-algebra framework. Existence of a certain canonical idempotent element is required and it plays a fundamental role, including the establishment of the coassociativity of the comultiplication. This class contains locally compact quantum groups as a subclass.
Synchrotron light sources in developing countries
Authors: Mtingwa Sekazi K. , Winick Herman
Published: March 2018

We discuss the role that synchrotron light sources, such as SESAME, could play in improving the socioeconomic conditions in developing countries. After providing a brief description of a synchrotron light source, we discuss the important role that they played in the development of several economically emerging countries. Then we describe the state of synchrotron science in South Africa and that country’s leadership role in founding the African Light Source initiative. Next, we highlight a new initiative called Lightsources for Africa, the Americas & Middle East Project, which is a global initiative led by the International Union of Pure and Applied Physics and the International Union of Crystallography, with initial funding provided by the International Council for Science. Finally, we comment on a new technology called the multibend achromat that has launched a new paradigm for the design of synchrotron light sources that should be attractive for construction in developing countries.
On the involution fixity of exceptional groups of Lie type
Authors: Burness Timothy C. , Thomas Adam R.
Published: March 2018

The involution fixity [Formula: see text] of a permutation group [Formula: see text] of degree [Formula: see text] is the maximum number of fixed points of an involution. In this paper we study the involution fixity of primitive almost simple exceptional groups of Lie type. We show that if [Formula: see text] is the socle of such a group, then either [Formula: see text], or [Formula: see text] and [Formula: see text] is a Suzuki group in its natural [Formula: see text]-transitive action of degree [Formula: see text]. This bound is best possible and we present more detailed results for each family of exceptional groups, which allows us to determine the groups with [Formula: see text]. This extends recent work of Liebeck and Shalev, who established the bound [Formula: see text] for every almost simple primitive group of degree [Formula: see text] with socle [Formula: see text] (with a prescribed list of exceptions). Finally, by combining our results with the Lang–Weil estimates from algebraic geometry, we determine bounds on a natural analogue of involution fixity for primitive actions of exceptional algebraic groups over algebraically closed fields.
Gröbner bases of neural ideals
Authors: Garcia Rebecca , Puente Luis David García , Kruse Ryan , Liu Jessica , Miyata Dane , Petersen Ethan , Phillipson Kaitlyn , Shiu Anne
Published: March 2018

The brain processes information about the environment via neural codes. The neural ideal was introduced recently as an algebraic object that can be used to better understand the combinatorial structure of neural codes. Every neural ideal has a particular generating set, called the canonical form, that directly encodes a minimal description of the receptive field structure intrinsic to the neural code. On the other hand, for a given monomial order, any polynomial ideal is also generated by its unique (reduced) Gröbner basis with respect to that monomial order. How are these two types of generating sets — canonical forms and Gröbner bases — related? Our main result states that if the canonical form of a neural ideal is a Gröbner basis, then it is the universal Gröbner basis (that is, the union of all reduced Gröbner bases). Furthermore, we prove that this situation — when the canonical form is a Gröbner basis — occurs precisely when the universal Gröbner basis contains only pseudo-monomials (certain generalizations of monomials). Our results motivate two questions: (1) When is the canonical form a Gröbner basis? (2) When the universal Gröbner basis of a neural ideal is not a canonical form, what can the non-pseudo-monomial elements in the basis tell us about the receptive fields of the code? We give partial answers to both questions. Along the way, we develop a representation of pseudo-monomials as hypercubes in a Boolean lattice.
Note on the question of Sikora
Authors: Storozhuk Konstantin
Published: March 2018

A natural topology on the set of left orderings on free abelian groups and free groups [Formula: see text], [Formula: see text] has studied in [A. S. Sikora, Topology on the spaces of orderings of groups, Bull. London Math. Soc. 36(4) (2004) 519–526; L. Smith, On ordering free groups, J. Symbolic Comput. 40 (2005) 1285–1290, Corrigendum (with A. Clay) 44 (2009) 1529–1532]. It has been proven already that in the abelian case the resulted topological space is a Cantor set. There was a conjecture: this is also true for the free group [Formula: see text] with [Formula: see text] generators. We point out the paper dealing with equivalent questions.
Bilocal fields and gravity
Authors: Diaz Pablo , Das Saurya , Walton Mark
Published: March 2018

We study a classical bilocal field theory perturbatively up to second-order. The chosen theory is the simplest which incorporates action-at-a-distance, while keeping nonlocal effects short-ranged. We show that the new degrees of freedom introduced by bilocality can be interpreted as gravitational degrees of freedom in the following sense: solutions of the bilocal system at linear and second-orders contain as a subset, gravitational perturbations (spacetime fluctuations) also to that order. In other words, gravity can be thought to originate in a bilocal field theory. We examine potential implications.
EFFECT OF LOW-TEMPERATURE ANNEALING ON STRUCTURE AND OPTICAL PROPERTIES OF AMORPHOUS TRIS(8-HYDROXYQUINOLINE) ALUMINUM FILMS
Authors: JIANG FENG , PANG ZHIYONG , YUAN HUIMIN , WEI ZHIXIAN , XIE WANFENG , HAN SHENGHAO
Published: March 2018

Needle-shaped nanostructured tris(8-hydroxyquinoline) aluminum nanowires (Alq3) have been obtained by annealing Alq3 amorphous films at 150∘C which is lower than the glass transition temperature of Alq3 (172∘C). The growth of Alq3 nanowires is attributed to the migration and stacking of Alq3 molecules which acquire thermal energy from the annealing process. X-ray diffraction analysis and scanning electronic microscopy spectra show that the Alq3 nanowires are composed of the well-known [Formula: see text]-phase Alq3. The intensity of the photoluminescence spectra firstly increases and then decreases as the annealing time increases, along with a spectral blue shift. The optical transmittance spectra of the annealed Alq3 films show a smaller average absorption in the visible range and a wider optical bandgap compared with that of the amorphous films, as a result of the decrease of [Formula: see text] overlapping in the Alq3 molecules.
A long chain of P-points
Authors: Kuzeljevic Borisa , Raghavan Dilip
Published: March 2018

The notion of a [Formula: see text]-generic sequence of P-points is introduced in this paper. It is proved assuming the Continuum Hypothesis (CH) that for each [Formula: see text], any [Formula: see text]-generic sequence of P-points can be extended to an [Formula: see text]-generic sequence. This shows that the CH implies that there is a chain of P-points of length [Formula: see text] with respect to both Rudin–Keisler and Tukey reducibility. These results answer an old question of Andreas Blass.
Extremal behavior in sectional matrices
Authors: Bigatti Anna , Palezzato Elisa , Torielli Michele
Published: March 2018

In this paper, we recall the object sectional matrix which encodes the Hilbert functions of successive hyperplane sections of a homogeneous ideal. We translate and/or reprove recent results in this language. Moreover, some new results are shown about their maximal growth, in particular, a new generalization of Gotzmann’s Persistence Theorem, the presence of a GCD for a truncation of the ideal, and applications to saturated ideals.
A result on p-hypercyclically embedded subgroups
Authors: Li Changwen , Huang Jianhong , Hu Bin
Published: March 2018

In this paper, a new characterization of [Formula: see text]-hypercyclical embeddability of a normal subgroup of a finite group is obtained based on the notion of [Formula: see text]-subgroups and some known results are generalized and extended.
Para-Kähler hom-Lie algebras
Authors: Peyghan E. , Nourmohammadifar L.
Published: March 2018

In this paper, we introduce the notions of pseudo-Riemannian, para-Hermitian and para-Kähler structures on hom-Lie algebras. In addition, we present the characterization of these structures. Also, we provide an example including these structures. We then introduce the phase space of a hom-Lie algebra and using the hom-left symmetric product, we show that a para-Kähler hom-Lie algebra gives a phase space and conversely, we can construct a para-Kähler hom-Lie algebra using a phase space.
A note on Lie ideals of prime rings
Authors: Lee Tsiu-Kwen , Mozumder Muzibur Rahman
Published: March 2018

In this paper, we characterize Lie ideals, which are either finitely generated [Formula: see text]-modules or maximal, in (centrally closed) prime rings. As consequences, we extend the results proved in [1] for finite dimensional central division algebras of characteristic not [Formula: see text] to simple rings of arbitrary characteristic.
Automorphisms of the k-algebra k[X1,…,Xm]
Authors: Petrescu-Nita Alina , Staic Mihai D.
Published: March 2018

For a field [Formula: see text] of characteristic [Formula: see text], we present an algorithm for deciding if a morphism [Formula: see text] has an inverse. The algorithm also shows how to find the inverse when it exists.
Combinatorics of extended affine root systems (type A1)
Authors: Azam Saeid , Kharaghani Zahra
Published: March 2018

We establish extensions of some important features of affine theory to affine reflection systems (extended affine root systems) of type [Formula: see text]. We present a positivity theory which decomposes in a natural way the nonisotropic roots into positive and negative roots, then using that, we give an extended version of the well-known exchange condition for the corresponding Weyl group, and finally give an extended version of the Bruhat ordering and the [Formula: see text]-Lemma. Furthermore, a new presentation of the Weyl group in terms of the parity permutations is given, this in turn leads to a parity theorem which gives a characterization of the reduced words in the Weyl group. All root systems involved in this work appear as the root systems of certain well-studied Lie algebras.
Alchemical free energy calculations and umbrella sampling with local molecular field theory
Authors: Remsing Richard C. , Weeks John D.
Published: March 2018

Understanding the thermodynamic driving forces underlying any chemical process requires a description of the underlying free energy surface. However, computation of free energies is difficult, often requiring advanced sampling techniques. Moreover, these computations can be further complicated by the evaluation of any long-ranged interactions in the system of interest, such as Coulomb interactions in charged and polar media. Local molecular field theory is a promising approach to avoid many of the conceptual and computational difficulties associated with long-ranged interactions. We present frameworks for performing alchemical free energy calculations and non-Boltzmann sampling with local molecular field theory. We demonstrate that local molecular field theory can be used to perform these free energy calculations with accuracy comparable to traditional methodologies while eliminating the need for explicit treatment of long-ranged interactions in simulations.
A mathematical model for the virus medical imaging technique
Authors: Fioranelli Massimo , Sepehri Alireza
Published: March 2018

In this paper, we introduce a mathematical model for the virus medical imaging (VMI). In this method, first, by proposing a mathematical model, we show that there are two types of viruses that each of them produce one type of signal. Some of these signals can be received by males and others by females. Then, we will show that in the VMI technique, viruses can communicate with cells, interior to human’s body via two ways. (1) Viruses can form a wire that passes the skin and reaches to a special cell. (2) Viruses can communicate with viruses interior to body in the wireless form and send some signals for controlling evolutions of cells interior to human’s body.
Dye-Sensitized-Assisted, Enhanced Photocatalytic Activity of TiO2/Bi4V2O11
Authors: Liang Mengjun , Yang Zhiyuan , Mei Ying , Zhou Haoran , Yang Shuijin
Published: March 2018

In this study, the TiO2/Bi4V2O[Formula: see text] nanocomposite photocatalysts were prepared by loading different amount of TiO2 nanoparticles onto the surface of Bi4V2O[Formula: see text] nanospheres via a facile hydrothermal method. Afterwards, the as-synthesized samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS) and photocurrent techniques. The optimal TiO2/Bi4V2O[Formula: see text] composite with 20[Formula: see text]wt.% TiO2 loading (TB2) exhibited the best photocatalytic activity, which could degrade almost RhB completely within 30[Formula: see text]min under visible light irradiation. The enhanced photocatalytic activity of TiO2/Bi4V2O[Formula: see text] composites for RhB degradation could be mainly ascribed to the efficient charge separation over dye-induced sensitized and the increased specific surface area. Also, the photocatalytic activities of TiO2/Bi4V2O[Formula: see text] for CIP degradation were tested. After five consecutive recycling experiments, the photocatalytic degradation activity of TB2 could still reach 99% which indicated that the catalysts had superior stability. Based on the experimental and bandgap calculations, a possible photocatalytic mechanism of TiO2/Bi4V2O[Formula: see text] for RhB degradation was proposed.
Cobalt–Nickel Oxides with Three-Dimensional Hexagon Films for High Performance Supercapacitors
Authors: Lv Yinan , Dong Guixia , Li Lei , Kang Jingrui , Han Weidan
Published: March 2018

Cobalt–nickel oxide electrode materials with three-dimensional hexagon films or flower-shaped structures have been synthesized by a chemical precipitation method at different thermal decomposition temperatures. Nickel ions enter into the lattice of Co3O4 by forming solid solution and promote primary nanoparticles partly self-assemble into three-dimensional hexagon films which interlace with each other to form a flower-like structure. Consequently, cobalt–nickel oxide with a Ni/Co mole ratio of 1:6 at 220[Formula: see text]C displays a highest capacitance of 796.16[Formula: see text]F/g at 200[Formula: see text]mA/g and cobalt–nickel oxide with a Ni/Co mole ratio of 1:3 at 200[Formula: see text]C exhibits a highest capacitance of 290[Formula: see text]F/g at 10[Formula: see text]A/g, which significantly improve the electrochemical properties of Co3O4.
Synthesis of Ag–SiO2–APTES Nanocomposites by Blending Poly(Vinylidene Fluoride) Membrane with Potential Applications on Dye Wastewater Treatment
Authors: Yu Zongxue , Min Xia , Li Fei , Chen Qi
Published: March 2018

In the study, the Ag–SiO2–APTES nanocomposite was synthesized via the self-assembly method to prepare Ag–SiO2 and subsequently used 3-aminopropyltriethoxysilane (APTES) to functionalize its surface. The as-prepared Ag–SiO2–APTES nanocomposite was embedded into poly(vinylidene fluoride) (PVDF) membrane by the co-blending way to fabricate the Ag–SiO2–APTES membrane. The Ag–SiO2–APTES nanocomposites were characterized by X-ray diffraction (XRD). These membrane materials were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and FT-IR spectra. The performance of membrane was investigated simultaneously for removing the organic dye methylene blue (MB), Rhodamine B, Direct Red 28 and anti-microbial ability. The experimental results demonstrated that the Ag–SiO2–APTES modified membrane were presented to be more hydrophilic with a contact angle 55.6[Formula: see text], whereas the pristine PVDF membrane was 81.8[Formula: see text]. The dye rejection ratios were also improved after adding Ag–SiO2–APTES, which reached 86.8% for MB, 87% Rhodamine B, 88% for Direct Red 28, besides, the removal rate of MB was about 98.7% at pH [Formula: see text] 11. More importantly, the Ag–SiO2–APTES membranes exhibited excellent antifouling properties for treating MB solution and could reach 85% of flux recovery ratio after four cyclic experiment. Finally, via inhibition zone method of antimicrobial test Ag–SiO2–APTES membrane exhibited the antimicrobial activity against Escherichia coli (E. coli) excellently. The novel antifouling and antibacterial Ag–SiO2–APTES membrane has a potential for dye wastewater treatment and water purity.
The stability and Hopf bifurcation for an HIV model with saturated infection rate and double delays
Authors: Lv Ying , Hu Zhixing , Liao Fucheng
Published: March 2018

An HIV infection model with saturated infection rate and double delays is investigated. First, the existence of the infection-free equilibrium [Formula: see text], the immune-exhausted equilibrium [Formula: see text] and the infected equilibrium [Formula: see text] with immunity in different conditions is shown. By analyzing the characteristic equation, we study the locally asymptotical stability of the trivial equilibrium, and the existence of Hopf bifurcations when two delays are used as the bifurcation parameter. Furthermore, we apply the Nyquist criterion to estimate the length of delay for which stability continues to hold. Then with suitable Lyapunov function and LaSalle’s invariance principle, the global stability of the three equilibriums is obtained. Finally, numerical simulations are presented to illustrate the main mathematical results.
Network and equation-based models in epidemiology
Authors: Edoh Kossi , MacCarthy Elijah
Published: March 2018

Network and equation-based (EB) models are two prominent methods used in the study of epidemics. While EB models use a global approach to model aggregate population, network models focus on the behavior of individuals in the population. The two approaches have been used in several areas of research, including finance, computer science, social science and epidemiology. In this study, epidemiology is used to contrast EB models with network models. The methods are based on the assumptions and properties of compartmental models. In EB models we solve a system of ordinary differential equations and in network models we simulate the spread of epidemics on contact networks using bond percolation. We examine the impact of network structures on the spread of infection by considering various networks, including Poisson, Erdős Rényi, Scale-free, and Watts–Strogatz small-world networks, and discuss how control measures can make use of the network structures. In addition, we simulate EB assumptions on Watts–Strogatz networks to determine when the results are similar to that of EB models. As a case study, we use data from the 1918 Spanish flu pandemic and that from measles outbreak to validate our results.
Numerical simulations of reaction–diffusion equations modeling prey–predator interaction with delay
Authors: Ali Ishtiaq , Rasool Ghulam , Alrashed Saleh
Published: March 2018

To model biological systems one often uses ordinary and partial differential equations. These equations can be quite good at approximating observed behavior, but they suffer from the downfall of containing many parameters, often signifying quantities which cannot be determined experimentally. For the better understanding of complicated phenomena, the delay differential equation approach to model such phenomena is becoming more and more essential to capture the rich variety of dynamics observed in natural systems. In this study, we investigated numerically the influence of delay on the dynamics of nonlinear reaction–diffusion equations modeling prey–predator interaction using finite difference scheme subject to appropriate initial and boundary conditions. We first consider the prey–predator with Holling type II functional response where the growth of prey is assumed to be logistic in the sense of predator in one-dimensional space. The effect of delay was investigated with the help of simulations and is compared with the model equation without delay. The proposed method is then extended to two-dimensional space.
Strong rainbow connection numbers of toroidal meshes
Authors: Wei Yulong , Xu Min , Wang Kaishun
Published: March 2018

In 2011, Li et al. [The (strong) rainbow connection numbers of Cayley graphs on Abelian groups, Comput. Math. Appl. 62(11) (2011) 4082–4088] obtained an upper bound of the strong rainbow connection number of an [Formula: see text]-dimensional undirected toroidal mesh. In this paper, this bound is improved. As a result, we give a negative answer to their problem.
Tele-Operated MRI-Guided Needle Insertion for Prostate Interventions
Authors: Moreira Pedro , Kuil Leanne , Dias Pedro , Borra Ronald , Misra Sarthak
Published: March 2018

Prostate cancer is one of the leading causes of death in men. Prostate interventions using magnetic resonance imaging (MRI) benefits from high tissue contrast if compared to other imaging modalities. The Minimally Invasive Robotics In An MRI environment (MIRIAM) robot is an MRI-compatible system able to steer different types of needles towards a point of interest using MRI guidance. However, clinicians can be reluctant to give the robot total control of the intervention. This work integrates a haptic device in the MIRIAM system to allow input from the clinician during the insertion. A shared control architecture is achieved by letting the clinician control the insertion depth via the haptic device, while the robotic system controls the needle orientation. The clinician receives haptic feedback based on the insertion depth and tissue characteristics. Four control laws relating the motion of the master robot (haptic device) to the motion of the slave robot (MIRIAM robot) are presented and evaluated. Quantitative and qualitative results from 20 human subjects demonstrate that the squared-velocity control law is the most suitable option for our application. Additionally, a pre-operative target localization algorithm is presented in order to provide the robot with the target location. The target localization and reconstruction algorithm are validated in phantom and patient images with an average dice similarity coefficient (DSC) of 0.78. The complete system is validated through experiments by inserting a needle towards a target within the MRI scanner. Four human subjects perform the experiment achieving an average targeting error of 3.4[Formula: see text]mm.
Event-Triggered 3D Needle Control Using a Reduced-Order Computationally Efficient Bicycle Model in a Constrained Optimization Framework
Authors: Carriere Jay , Khadem Mohsen , Rossa Carlos , Usmani Nawaid , Sloboda Ronald , Tavakoli Mahdi
Published: March 2018

Long flexible needles used in percutaneous procedures such as biopsy and brachytherapy deflect during insertion, thus reducing needle tip placement accuracy. This paper presents a surgeon-in-the-loop system to automatically steer the needle during manual insertion and compensate for needle deflection using an event-triggered controller. A reduced-order kinematic bicycle model incorporating needle tip measurement data from ultrasound images is used to determine steering actions required to minimize needle deflection. To this end, an analytic solution to the reduced-order bicycle model, which is shown to be more computationally efficient than a discrete-step implementation of the same model, is derived and utilized for needle tip trajectory prediction. These needle tip trajectory predictions are used online to optimize the insertion depths (event-trigger points) for steering actions such that needle deflection is minimized. The use of the analytic model and the event-triggered controller also allows for limiting the number and extent of needle rotations (to reduce tissue trauma) in a constrained optimization framework. The system was tested experimentally in three different ex-vivo tissue phantoms with a surgeon-in-the-loop needle insertion device. The proposed needle steering controller was shown to keep the average needle deflection within 0.47 [Formula: see text] 0.21[Formula: see text]mm at the final insertion depth of 120[Formula: see text]mm.
Voltammetric Perspectives on the Acidity Scale and H+/H2 Process in Ionic Liquid Media
Authors: Bentley Cameron L. , Bond Alan M. , Zhang Jie
Published: March 2018

Nonhaloaluminate ionic liquids (ILs) have received considerable attention as alternatives to molecular solvents in diverse applications spanning the fields of physical, chemical, and biological science. One important and often overlooked aspect of the implementation of these designer solvents is how the properties of the IL formulation affect (electro)chemical reactivity. This aspect is emphasized herein, where recent (voltammetric) studies on the energetics of proton (H+) transfer and electrode reaction mechanisms of the H+/H2 process in IL media are highlighted and discussed. The energetics of proton transfer, quantified using the p Ka (minus logarithm of acidity equilibrium constant, Ka) formalism, is strongly governed by the constituent IL anion, and to a lesser extent, the IL cation. The H+/H2 process, a model inner-sphere reaction, also displays electrochemical characteristics that are strongly IL-dependent. Overall, these studies highlight the need to carry out systematic investigations to resolve IL structure and function relationships in order to realize the potential of these diverse and versatile solvents.