bluuebunny/crossref_metadata_2025_split huggingface dataset:
Directed Self‐Assembly of Star‐Block Copolymers by Topographic Nanopatterns through Nucleation and Growth Mechanism
Authors: Krishnan Mohan Raj , Lu Kai‐Yuan , Chiu Wen‐Yu , Chen I‐Chen , Lin Jheng‐Wei , Lo Ting‐Ya , Georgopanos Prokopios , Avgeropoulos Apostolos , Lee Ming‐Chang , Ho Rong‐Ming 
Published: March 2018

AbstractExploring the ordering mechanism and dynamics of self‐assembled block copolymer (BCP) thin films under confined conditions are highly essential in the application of BCP lithography. In this study, it is aimed to examine the self‐assembling mechanism and kinetics of silicon‐containing 3‐arm star‐block copolymer composed of polystyrene (PS) and poly(dimethylsiloxane) blocks as nanostructured thin films with perpendicular cylinders and controlled lateral ordering by directed self‐assembly using topographically patterned substrates. The ordering process of the star‐block copolymer within fabricated topographic patterns with PS‐functionalized sidewall can be carried out through the type of secondary (i.e., heterogeneous) nucleation for microphase separation initiated from the edge and/or corner of the topographic patterns, and directed to grow as well‐ordered hexagonally packed perpendicular cylinders. The growth rate for the confined microphase separation is highly dependent upon the dimension and also the geometric texture of the preformed pattern. Fast self‐assembly for ordering of BCP thin film can be achieved by lowering the confinement dimension and also increasing the concern number of the preformed pattern, providing a new strategy for the design of BCP lithography from the integration of top‐down and bottom‐up approaches.
Nanodiamonds and Their Applications in Cells
Authors: Chipaux Mayeul , van der Laan Kiran J. , Hemelaar Simon R. , Hasani Masoumeh , Zheng Tingting , Schirhagl Romana 
Published: March 2018

AbstractDiamonds owe their fame to a unique set of outstanding properties. They combine a high refractive index, hardness, great stability and inertness, and low electrical but high thermal conductivity. Diamond defects have recently attracted a lot of attention. Given this unique list of properties, it is not surprising that diamond nanoparticles are utilized for numerous applications. Due to their hardness, they are routinely used as abrasives. Their small and uniform size qualifies them as attractive carriers for drug delivery. The stable fluorescence of diamond defects allows their use as stable single photon sources or biolabels. The magnetic properties of the defects make them stable spin qubits in quantum information. This property also allows their use as a sensor for temperature, magnetic fields, electric fields, or strain. This Review focuses on applications in cells. Different diamond materials and the special requirements for the respective applications are discussed. Methods to chemically modify the surface of diamonds and the different hurdles one has to overcome when working with cells, such as entering the cells and biocompatibility, are described. Finally, the recent developments and applications in labeling, sensing, drug delivery, theranostics, antibiotics, and tissue engineering are critically discussed.
A Modular System for the Design of Stimuli‐Responsive Multifunctional Nanoparticle Aggregates by Use of Host–Guest Chemistry
Authors: Engel Sabrina , Möller Nadja , Stricker Lucas , Peterlechner Martin , Ravoo Bart Jan 
Published: March 2018

AbstractA self‐assembly approach for the design of multifunctional nanomaterials consisting of different nanoparticles (gold, iron oxide, and lanthanide‐doped LiYF4) is developed. This modular system takes advantage of the light‐responsive supramolecular host–guest chemistry of β‐cyclodextrin and arylazopyrazole, which enables the dynamic and reversible self‐assembly of particles to spherical nanoparticle aggregates in aqueous solution. Due to the magnetic iron oxide nanoparticles, the aggregates can be manipulated by an external magnetic field leading to the formation of linear structures. As a result of the integration of upconversion nanoparticles, the aggregates are additionally responsive to near‐infrared light and can be redispersed by use of the upconversion effect. By varying the nanoparticle and linker concentrations the composition, size, shape, and properties of the multifunctional nanoparticle aggregates can be fine‐tuned.
Supramolecular Vesicles for Stimulus‐Responsive Drug Delivery
Authors: Xing Pengyao , Zhao Yanli 
Published: March 2018

AbstractDeveloping smart controlled‐release systems for cancer therapy is highly desired in biomedicine. In order to improve therapeutic efficacy and lower undesired side effects, the construction of stimulus‐responsive nanocarriers is a favorable solution. Emerging supramolecular self‐assemblies possessing intrinsic dynamic and adaptive features present promising capabilities for the fabrication of stimulus‐responsive drug‐release systems. Dynamic supramolecular vesicles have attracted considerable attention as therapeutic carriers ascribed to their advantages of high‐cargo‐loading capacity/feasibility, excellent biocompatibility, and facile functionalization. Here, a summary and discussion of recent significant development of vesicles constructed by supramolecular self‐assembly for stimulus‐responsive drug delivery and therapeutics is given. Through presenting some representative studies, strategies regarding the design, synthesis, characterization, and biomedical applications of supramolecular vesicle carriers are highlighted according to various stimulus triggers. The aim is to provide a quick research update in this rapidly developing field.
A Hierarchical MoP Nanoflake Array Supported on Ni Foam: A Bifunctional Electrocatalyst for Overall Water Splitting
Authors: Jiang Yuanyuan , Lu Yizhong , Lin Jianyi , Wang Xin , Shen Zexiang 
Published: March 2018

AbstractThe search for an inexpensive bifunctional electrocatalyst for overall water splitting has attracted considerable research interest during the past years. Herein, self‐supported hierarchical electrodes comprising nickel foam (NF) and porous molybdenum phosphide (MoP) nanoflakes are fabricated by first growing MoO2 nanoflakes on Ni foam and then further phosphorization treatment. Remarkably, serving as both anode and cathode catalysts in a two‐electrode alkaline water‐electrolysis system, the designed electrodes only require a potential of 1.62 V to deliver a current density of 10 mA cm−2. This performance is close to that of the noble‐metal‐based electrodes, that is, integrated RuO2/Ni foam and Ni foam supported Pt/C electrodes. The low cost, facile preparation method, and desirable performance make this MoP/NF electrode a potential electrocatalyst for overall water splitting.
From Solute, Fluidic and Particulate Precursors to Complex Organizations of Matter
Authors: Rao Ashit , Cölfen Helmut 
Published: March 2018

AbstractThe organization of matter from its constitutive units recruits intermediate states with distinctive degrees of self‐association and molecular order. Existing as clusters, droplets, gels as well as amorphous and crystalline nanoparticles, these precursor forms have fundamental contributions towards the composition and structure of inorganic and organic architectures. In this personal account, we show that the transitions from atoms, molecules or ionic species to superstructures of higher order are intertwined with the interfaces and interactions of precursor and intermediate states. Structural organizations distributed across different length scales are explained by the multistep nature of nucleation and crystallization, which can be guided towards functional hybrid materials by the strategic application of additives, templates and reaction environments. Thus, the non‐classical pathways for material formation and growth offer conceptual frameworks for elucidating, inducing and directing fascinating material organizations of biogenic and synthetic origins.
A mechanobiologically equilibrated constrained mixture model for growth and remodeling of soft tissues
Authors: Latorre Marcos , Humphrey Jay D. 
Published: March 2018

AbstractGrowth and remodeling of soft tissues is a dynamic process and several theoretical frameworks have been developed to analyze the time‐dependent, mechanobiological and/or biomechanical responses of these tissues to changes in external loads. Importantly, general processes can often be conveniently separated into truly non‐steady contributions and steady‐state ones. Depending on characteristic times over which the external loads are applied, time‐dependent models can sometimes be specialized to respective time‐independent formulations that simplify the mathematical treatment without compromising the goodness of the particularized solutions. Very few studies have analyzed the long‐term, steady‐state responses of soft tissue growth and remodeling following a direct approach. Here, we derive a mechanobiologically equilibrated formulation that arises from a general constrained mixture model. We see that integral‐type evolution equations that characterize these general models can be written in terms of an equivalent set of time‐independent, nonlinear algebraic equations that can be solved efficiently to yield long‐term outcomes of growth and remodeling processes in response to sustained external stimuli. We discuss the mathematical conditions, in terms of orders of magnitude, that yield the particularized equations and illustrate results numerically for general arterial mechano‐adaptations.
Correction to: Explicit upper bound for the average number of divisors of irreducible quadratic polynomials
Authors: Lapkova Kostadinka 
Published: March 2018

Abstract
Consider the divisor sum

$$\sum _{n\le N}\tau (n^2+2bn+c)$$

∑

n
≤
N

τ

(

n
2

+
2
b
n
+
c
)

for integers b and c. We improve the explicit upper bound of this average divisor sum in certain cases, and as an application, we give an improvement in the maximal possible number of

$$D(-1)$$

D
(
-
1
)

-quadruples. The new tool is a numerically explicit Pólya–Vinogradov inequality, which has not been formulated explicitly before but is essentially due to Frolenkov–Soundararajan.
Substrate selection of adenylation domains for nonribosomal peptide synthetase (NRPS) in bacillamide C biosynthesis by marine Bacillus atrophaeus C89
Authors: Zhang Fengli , Wang Yukun , Jiang Qun , Chen Qihua , Karthik Loganathan , Zhao Yi-Lei , Li Zhiyong 
Published: March 2018

Abstract
Nonribosomal peptide synthetases (NRPSs) are multi-modular enzymes involved in the biosynthesis of natural products. Bacillamide C was synthesized by Bacillus atrophaeus C89. A nonribosomal peptide synthetase (NRPS) cluster found in the genome of B. atrophaeus C89 was hypothesized to be responsible for the biosynthesis of bacillamide C using alanine and cysteine as substrates. Here, the structure analysis of adenylation domains based on homologous proteins with known crystal structures indicated locations of the substrate-binding pockets. Molecular docking suggested alanine and cysteine as the potential substrates for the two adenylation domains in the NRPS cluster. Furthermore, biochemical characterization of the purified recombinant adenylation domains proved that alanine and cysteine were the optimum substrates for the two adenylation domains. The results provided the in vitro evidence for the hypothesis that the two adenylation domains in the NRPS of B. atrophaeus C89 preferentially select alanine and cysteine, respectively, as a substrate to synthesize bacillamide C. Furthermore, this study on substrates selectivity of adenylation domains provided basis for rational design of bacillamide analogs.
Enhanced lincomycin production by co-overexpression of metK1 and metK2 in Streptomyces lincolnensis
Authors: Xu Yurong , Tan Guoqing , Ke Meilan , Li Jie , Tang Yaqian , Meng Sitong , Niu Jingjing , Wang Yansheng , Liu Ruihua , Wu Hang , Bai Linquan , Zhang Lixin , Zhang Buchang 
Published: March 2018

Abstract
Streptomyces lincolnensis is generally utilized for the production of lincomycin A (Lin-A), a clinically useful antibiotic to treat Gram-positive bacterial infections. Three methylation steps, catalyzed by three different S-adenosylmethionine (SAM)-dependent methyltransferases, are required in the biosynthesis of Lin-A, and thus highlight the significance of methyl group supply in lincomycin production. In this study, we demonstrate that externally supplemented SAM cannot be taken in by cells and therefore does not enhance Lin-A production. Furthermore, bioinformatics and in vitro enzymatic assays revealed there exist two SAM synthetase homologs, MetK1 (SLCG_1651) and MetK2 (SLCG_3830) in S. lincolnensis that could convert l-methionine into SAM in the presence of ATP. Even though we attempted to inactivate metK1 and metK2, only metK2 was deleted in S. lincolnensis LCGL, named as ΔmetK2. Following a reduction of the intracellular SAM concentration, ΔmetK2 mutant exhibited a significant decrease of Lin-A in comparison to its parental strain. Individual overexpression of metK1 or metK2 in S. lincolnensis LCGL either elevated the amount of intracellular SAM, concomitant with 15% and 22% increase in Lin-A production, respectively. qRT-PCR assays showed that overexpression of either metK1 or metK2 increased the transcription of lincomycin biosynthetic genes lmbA and lmbR, and regulatory gene lmbU, indicating SAM may also function as a transcriptional activator. When metK1 and metK2 were co-expressed, Lin-A production was increased by 27% in LCGL, while by 17% in a high-yield strain LA219X.
Multiscale and age‐dependent leaf nickel in the Ni‐hyperaccumulator Leptoplax emarginata
Authors: Bartoli François , Royer Mathilde , Coinchelin David , Le Thiec Didier , Rose Christophe , Robin Christophe , Echevarria Guillaume 
Published: March 2018

AbstractNickel‐hyperaccumulator plants are of interest due to their potential use in agromining. We aimed to characterize leaf traits and Ni concentration variabilities occurring between individual plants, leaves of differing age or between various leaf tissues, in a single Greek population of the Ni‐hyperaccumulator Leptoplax emarginata (Boiss.) O.E. Schulz. We linked these results to ecophysiological characteristics and other element concentrations at leaf and leaf tissue scales. We measured leaf gas exchanges, stomatal density, and we carried out rapid freezing and freeze‐drying processes on leaf sections before microanalysis with scanning electron microscopy and energy‐dispersive spectrometry. Leaf or leaf‐tissue Ni concentrations were influenced by a combination of individual plant and leaf age factors. The greatest Ni concentrations were found in the highly transpiring young and thin leaves with the greatest stomatal densities. Indeed, Ni was statistically seven times more concentrated in both epidermis layers than in their bulk neighbour leaf counterparts, whatever the leaf age. In both epidermis layers, increases in the Ni–S and Mg–S correlations from the oldest leaves to the youngest ones were observed. The Mg:Ni, Ca:Ni and P:Ni mass ratios decreased from the oldest leaves to the mature leaves. We would recommend time‐series characterization of leaf traits belonging to at least three plant replicates in order to take into account the allogamous character of many Ni‐hyperaccumulator plants. Long‐distance Ni transport via the xylem is predominant in the Ni‐hyperaccumulator L. emarginata whereas a complementary redistribution via the phloem should also occur. The perspectives of this study are the validation and refinement of this process over shorter periods using relevant tracers.
Hemorrhoids and related complications in primigravid pregnancy
Authors: Beksac Kemal , Aydin Emine , Uzelpasacı Esra , Akbayrak Turkan , Ozyuncu Ozgur 
Published: March 2018

Abstract
Purpose To identify the effect of pregnancy on the development of external hemorrhoids and constipation.
Subjects and methods This pilot study involved 61 primigravid women without a history of perianal diseases. Each patient was examined and filled a questionnaire between the 11th and 14th gestational week prior to prenatal screening tests. Patients were re-examined and questioned in relation to perianal symptoms and hemorrhoidal changes again in the 24th and 37th gestational weeks.
Results A total of 5, 8, and 11 women had symptomatic external hemorrhoids with or without perianal complications in the 11–14th, 24th, and 37th gestational weeks, respectively. Meanwhile, 27, 25, and 29 women complained about constipation in the 11–14th, 24th, and 37th gestational weeks, respectively. Only 4 (6.6%) patients experienced painful hemorrhoids. The overall morbidity rate was 18% (11 cases). We found a statistically significant relationship between external hemorrhoids/perianal complications and gestation-induced constipation through logistic regression analysis (p < 0.001).
Conclusion Various risk factors and biological explanations exist for the high frequency of hemorrhoids during pregnancy. Because participants were primigravid women without a history of perianal complaints, findings suggest a direct effect of pregnancy itself on the development of external hemorrhoids/perianal symptoms.
Relationships Among Perceived Functional Capacity, Self‐Efficacy, and Disability After Dysvascular Amputation
Authors: Miller Matthew J. , Magnusson Dawn M. , Lev Guy , Fields Thomas T. , Cook Paul F. , Stevens‐Lapsley Jennifer E. , Christiansen Cory L. 
Published: March 2018

AbstractBackgroundProsthesis rehabilitation after dysvascular transtibial amputation (TTA) is focused on optimizing functional capacity with limited emphasis on promoting health self‐efficacy. Self‐efficacy interventions decrease disability for people living with chronic disease, but the influence of self‐efficacy on disability is unknown for people with dysvascular TTA.ObjectivesTo identify if self‐efficacy mediates the relationship between self‐reported functional capacity and disability after dysvascular TTA.DesignCross‐sectional, secondary data analysis.SettingOutpatient rehabilitation facilities.ParticipantsThirty‐eight men (63.6 ± 9.1 years old) with dysvascular TTA.MethodsParticipants had been living with an amputation for less than 6 months and using walking as their primary form of locomotion using a prosthesis. The independent variable, functional capacity, was measured using the Prosthesis Evaluation Questionnaire–Mobility Scale (PEQ‐MS). The proposed mediator, self‐efficacy, was measured with the Self‐Efficacy of Managing Chronic Disease questionnaire (SEMCD).Main Outcome MeasureDisability was measured using the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) questionnaire.ResultsThe relationship between self‐reported functional capacity and disability is partially mediated by self‐efficacy. Relationships between WHODAS 2.0 and PEQ‐MS (r = –0.61), WHODAS 2.0 and SEMCD (r = –0.51), and PEQ‐MS and SEMCD (r = 0.44) were significant (P < .01). Controlling for SEMCD (P = .04), the relationship between PEQ‐MS and WHODAS 2.0 remained significant (P < .01). Statistically significant mediation was determined by a bootstrap method for the product of coefficients (95% confidence interval: –2.23, –7.39).ConclusionsThis study provides initial evidence that the relationship between self‐reported functional capacity and disability is partially mediated by self‐efficacy after dysvascular TTA. The longitudinal effect of self‐efficacy should be further examined to identify causal pathways of disability after dysvascular amputation. Furthermore, additional factors contributing to the relationship between self‐reported functional capacity and disability need to be identified.Level of EvidenceIII
Anomalous Brain Development Is Evident in Preschoolers With Attention-Deficit/Hyperactivity Disorder
Authors: Jacobson Lisa A. , Crocetti Deana , Dirlikov Benjamin , Slifer Keith , Denckla Martha Bridge , Mostofsky Stewart H. , Mahone E. Mark 
Published: March 2018

AbstractObjectives: Attention-deficit/hyperactivity disorder (ADHD) is a common neurological disorder with symptom onset early in childhood. Growing evidence suggests anomalous brain development across multiple brain regions is evident in school-aged children; however, few studies have examined whether such differences are notable in the preschool years when symptom onset typically occurs. Methods: High resolution anatomical (MPRAGE) images and cognitive and behavioral measures were analyzed in a total of 90 medication-naïve preschoolers, ages 4–5 years (52 with ADHD, 38 controls; 64.4% boys). Results: Results revealed reductions in bilateral frontal, parietal, and temporal lobe gray matter volumes in children with ADHD relative to typically developing children, with largest effect sizes noted for right frontal and left temporal lobe volumes. Examining frontal lobe sub-regions, the largest between group effect sizes were evident for left orbitofrontal cortex, left primary motor cortex (M1), and left supplementary motor complex (SMC). ADHD-related reductions in specific sub-regions (left prefrontal, left premotor, left frontal eye field, left M1, and right SMC) were significantly correlated with symptom severity, such that higher ratings of hyperactive/impulsive symptoms were associated with reduced cortical volumes. Conclusions: These findings represent the first comprehensive examination of cortical volume in preschool children with ADHD, providing evidence that anomalous brain structure in ADHD is evident very early in development. Furthermore, findings set the stage for developing our understanding of the way in which developmental trajectories of anomalous brain development are associated with the unfolding of symptoms in childhood ADHD. (JINS, 2018, 24, 531–539)
Importance of Serum Amino Acid Profile for Induction of Hepatic Steatosis under Protein Malnutrition
Authors: Nishi Hiroki , Yamanaka Daisuke , Kamei Hiroyasu , Goda Yuki , Kumano Mikako , Toyoshima Yuka , Takenaka Asako , Masuda Masato , Nakabayashi Yasushi , Shioya Ryuji , Kataoka Naoyuki , Hakuno Fumihiko , Takahashi Shin-Ichiro 
Published: March 2018

AbstractWe previously reported that a low-protein diet caused animals to develop fatty liver containing a high level of triglycerides (TG), similar to the human nutritional disorder “kwashiorkor”. To investigate the underlying mechanisms, we cultured hepatocytes in amino acid-sufficient or deficient medium. Surprisingly, the intracellular TG level was increased by amino acid deficiency without addition of any lipids or hormones, accompanied by enhanced lipid synthesis, indicating that hepatocytes themselves monitored the extracellular amino acid concentrations to induce lipid accumulation in a cell-autonomous manner. We then confirmed that a low-amino acid diet also resulted in the development of fatty liver, and supplementation of the low-amino acid diet with glutamic acid to compensate the loss of nitrogen source did not completely suppress the hepatic TG accumulation. Only a dietary arginine or threonine deficiency was sufficient to induce hepatic TG accumulation. However, supplementation of a low-amino acid diet with arginine or threonine failed to reverse it. In silico analysis succeeded in predicting liver TG level from the serum amino acid profile. Based on these results, we conclude that dietary amino acid composition dynamically affects the serum amino acid profile, which is sensed by hepatocytes and lipid synthesis was activated cell-autonomously, leading to hepatic steatosis.
High‐gain 2 × 2 UWB antenna array with integrated phase inverter
Authors: Hasan M.N. , Seo M. 
Published: March 2018

A compact 2 × 2 ultra wideband (UWB) antenna array, composed of four planar rectangular monopoles, with a novel feeding network scheme is presented. The feeding network contains a power divider with a wideband balun and a 180° phase inverter in order to add the radiated electric fields of the array elements in‐phase. A partial ground plane is used to achieve ultra wide bandwidth. The antenna array has a measured impedance bandwidth from 2.5 to 5.5 GHz with broadside radiation pattern and a measured peak gain of 13 dBi. The proposed array is suitable for portable UWB systems.