bluuebunny/crossref_metadata_2025 huggingface dataset:
Nickel‐Catalyzed Difluoroalkylation of (Hetero)Arylborons with Unactivated 1‐Bromo‐1,1‐difluoroalkanes
Authors: Xiao Yu‐Lan , Min Qiao‐Qiao , Xu Chang , Wang Ruo‐Wen , Zhang Xingang
Published: April 2016

A nickel‐catalyzed cross‐coupling between (hetero)arylborons and unactivated 1‐bromo‐1,1‐difluoroalkanes has been developed. The use of two ligands (a bidentate bipyridine‐based ligand, 4,4′‐ditBu‐bpy, and a monodentate pyridine‐based ligand, DMAP) offers a highly efficient nickel‐based catalytic system to prepare difluoroalkylated arenes which have important applications in medicinal chemistry.
Structural Polymorphism and Thin Film Transistor Behavior in the Fullerene Framework Molecule 5,6;11,12‐di‐o‐Phenylenetetracene
Authors: Wombacher Tobias , Gassmann Andrea , Foro Sabine , von Seggern Heinz , Schneider Jörg J.
Published: April 2016

The molecular structure of the hydrocarbon 5,6;11,12‐di‐o‐phenylenetetracene (DOPT), its material characterization and evaluation of electronic properties is reported for the first time. A single‐crystal X‐ray study reveals two different motifs of intramolecular overlap with herringbone‐type arrangement displaying either face‐to‐edge or co‐facial face‐to‐face packing depicting intensive π–π interactions. Density functional theory (DFT) calculations underpin that a favorable electronic transport mechanism occurs by a charge hopping process due to a π‐bond overlap in the DOPT polymorph with co‐facial arene orientation. The performance of polycrystalline DOPT films as active organic semiconducting layer in a state‐of‐the‐art organic field effect transistor (OFET) device was evaluated and proves to be film thickness dependent. For 40 nm layer thickness it displays a saturation hole mobility (μhole) of up to 0.01 cm2 V−1 s−1 and an on/off‐ratio (Ion/Ioff) of 1.5×103.
Concise Synthesis of a Pateamine A Analogue with In Vivo Anticancer Activity Based on an Iron‐Catalyzed Pyrone Ring Opening/Cross‐Coupling
Authors: Zhuo Chun‐Xiang , Fürstner Alois
Published: April 2016

The marine macrolide pateamine A and its non‐natural sibling DMDA‐Pat A are potent translation inhibitors targeting the eukaryotic initiation factor 4A (eIF4A), an enzyme with RNA helicase activity. Although essential for every living cell, this protein target seems “drugable” since DMDA‐Pat A has previously been shown to exhibit remarkable in vivo activity against two different melanoma mouse models. The novel entry into this promising compound presented herein is shorter and significantly more productive than the literature route. Key to success was the masking of the signature Z,E‐configured dienoate subunit of DMDA‐Pat A in the form of a 2‐pyrone ring, which was best crafted by a gold‐catalyzed cyclization. While the robustness of the heterocycle facilitated the entire assembly stage, the highly isomerization‐prone seco‐Z,E‐dienoic acid could be unlocked in due time for macrolactonization by an unconventional iron‐catalyzed ring opening/cross coupling. Moreover, the crystal structure analysis of an advanced intermediate gave first insights into the conformation of the macrodilactone framework of the pateamine family, which is thought to be critical for eliciting the desired biological response.
Synthesis of homoallylic amines and acylhydrazides by tin powder‐promoted multicomponent one‐pot allylation reactions
Authors: Ma Junyan , Huang Danfeng , Wang Ke‐Hu , Xu Yanli , Chong Siying , Su Yingpeng , Fu Ying , Hu Yulai
Published: April 2016

An efficient process for the synthesis of homoallylic amines and N′‐homoallylic hydrazides is developed from the one‐pot reaction of carbonyl compounds, amines or N‐acylhydrazines, allyllic bromide and tin powder using water as solvent. N‐Acylhydrazines are found to be more reactive than amines in these processes. They can react not only with aldehydes but also with ketones to give the corresponding N′‐homoallylic hydrazides. Copyright © 2016 John Wiley & Sons, Ltd.
Preparation of hydrogel impregnated antimicrobial polyurethane foam for absorption of radionuclide contaminated blood and biological fluids
Authors: Kaur Avneet , Chattopadhyay Sruti , Jain Swati , Tyagi Amit , Singh Harpal
Published: April 2016

Multi‐purpose polyacrylamide (PAM) and polyacrylamide‐co‐sodiumpolyacrylate (PAM‐co‐NaPA) impregnated polyurethane foams (PUF) loaded with iodine have been prepared by in situ free radical polymerization. The prepared hydrogel networks displayed higher capacity for absorbing biological fluids as compared to regular PUF sheets and cotton matrices used in hospitals for maintaining hygiene conditions in cases of blood spillage and leakages. PAM‐impregnated‐PUF showed 910, 605, and 172% absorption in water, saline, and blood, respectively, whereas PAM‐co‐NaPA‐impregnated‐PUF showed absorption of 1545, 1395, and 269% in water, saline, and blood, respectively in 24 h. Exposure to nuclear, biological, and chemical (NBC) environment has become a grave predicament in today's world necessitating prevention of radiological contaminations especially in medical facilities. PAM‐co‐NaPA‐impregnated‐PUF displayed 97% absorption of Tc99 from whole blood whereas PUF sheets were highly hydrophobic and showed only 1% absorption of Tc99 from whole blood. It was also demonstrated that modified foams have long‐term broad‐spectrum antimicrobial properties due to sustain release of ionic iodine. Thus, PAM‐co‐NaPA‐impregnated‐PUF sheets have strong potential to be used as matrices for carrying the injured patients, from field conditions to hospitals expose to NBC environment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43625.
Healing of polymeric artificial muscle reinforced ionomer composite by resistive heating
Authors: Zhang Pengfei , Ayaugbokor Ukeamezhim , Ibekwe Samuel , Jerro Dwayne , Pang Su‐Seng , Mensah Patrick , Li Guoqiang
Published: April 2016

In this study, structural‐scale crack healing of artificial muscle reinforced ionomer composite was investigated following the close‐then‐heal (CTH) healing strategy. Structural‐scale crack of 3 mm deep and 1 mm wide in notched beam specimens was first closed by actuation of the embedded polymeric artificial muscles made of fishing lines, followed by intrinsic healing of the ionomer matrix. The healing process was triggered by resistive heating of embedded carbon fibers by DC power. It is found that, with 0.7% by volume of polymeric artificial muscles, the wide‐opened cracks are effectively closed, and the closed cracks in the ionomer composite are effectively and repeatedly healed, with a healing efficiency of over 80%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43660.
Relaxation behavior and activation energy of relaxation for polyimide and polyimide–graphene nanocomposite
Authors: Marashdeh Wajeeh F. , Longun Jimmy , Iroh Jude O.
Published: April 2016

The relaxation behavior of polyimide and its nanocomposite containing 10 wt % of graphene was studied by using the dynamic mechanical spectrometer. Dynamic mechanical analysis of polyimide and its composite was performed as a function of temperature and frequency in the temperature range of 25–480 °C and frequency range between 0.05 and 100 Hz. The effect of increasing frequency of testing from 0.05 to 100 Hz is a significant shift from the glass transition temperature, Tg, to higher temperature from 360 °C at 0.05 Hz to 420 °C at 100 Hz. The tan δ peak height for both α and β transitions decreased with increasing test frequency from 0.24 at 0.05 Hz to 0.08 at 100 Hz, due to increasing restriction to chain motion. At any given testing frequency, the Tg for the composite was shown to be higher than that for the matrix by about 5–10 °C. The Arrhenius equation was used to calculate the activation energy for both α and β transitions. The activation for α and β transitions for the composite and polyimide matrix were determined to be 688 and 537 kJ/mol and 313 and 309 kJ/mol, respectively, indicating that a significant increase in the energy barrier to chain relaxation occurred as a result of reinforcement of polyimide with low weight fraction of graphene. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43684.
Ag‐nanocomposite based on carboxymethylcellulose for humidity detection: Green synthesis and sensing performances
Authors: Marzouk Wiem , Sakly Nawfel , Roudesli Sadok , Ben Ouada Hafedh , Majdoub Hatem
Published: April 2016

A novel highly sensitive Ag‐nanocomposite for humidity detection has been successfully prepared. Initially, cellulose isolated from Tunisian palm date petiole was converted to carboxymethyl cellulose (CMC) as biomatrix under heterogeneous conditions. The synthesized product was thoroughly characterized by means of FT‐IR spectroscopy, viscosity analysis, and high performance size exclusion chromatography multiangle laser light scattering. CMC was used as reducing and stabilizing agent to prepare CMC‐stabilized silver nanoparticles via a rapid green method. The bioreduction of silver ions under different experimental conditions, including Ag+ concentration and pH, was investigated. Optimal experimental conditions provided a long‐term stable colloidal suspension and well‐dispersed spherical shape Ag NPs with a size ranging from 13 to 28 nm. Ag‐nanocomposite coated quartz microbalance crystal was used as sensitive layer for humidity detection. A comparative study showed that the immobilized metallic nanostructures greatly reduced changes in visco‐elastic properties, increased surface area as well as surface local charge density of the CMC. Consequently, sensor performances were greatly enhanced: better stability even at higher relative humidity (RH), good reproducibility and linearity (11–98% RH), low hysteresis characteristics, and rapid response and recovery times (14 and 6 s, respectively) were obtained. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43686.
TRANSLATING ECOLOGY, PHYSIOLOGY, BIOCHEMISTRY, AND POPULATION GENETICS RESEARCH TO MEET THE CHALLENGE OF TICK AND TICK‐BORNE DISEASES IN NORTH AMERICA
Authors: Esteve‐Gassent Maria D. , Castro‐Arellano Ivan , Feria‐Arroyo Teresa P. , Patino Ramiro , Li Andrew Y. , Medina Raul F. , de León Adalberto A. Pérez , Rodríguez‐Vivas Roger Iván
Published: April 2016

Emerging and re‐emerging tick‐borne diseases threaten public health and the wellbeing of domestic animals and wildlife globally. The adoption of an evolutionary ecology framework aimed to diminish the impact of tick‐borne diseases needs to be part of strategies to protect human and animal populations. We present a review of current knowledge on the adaptation of ticks to their environment, and the impact that global change could have on their geographic distribution in North America. Environmental pressures will affect tick population genetics by selecting genotypes able to withstand new and changing environments and by altering the connectivity and isolation of several tick populations. Research in these areas is particularly lacking in the southern United States and most of Mexico with knowledge gaps on the ecology of these diseases, including a void in the identity of reservoir hosts for several tick‐borne pathogens. Additionally, the way in which anthropogenic changes to landscapes may influence tick‐borne disease ecology remains to be fully understood. Enhanced knowledge in these areas is needed in order to implement effective and sustainable integrated tick management strategies. We propose to refocus ecology studies with emphasis on metacommunity‐based approaches to enable a holistic perspective addressing whole pathogen and host assemblages. Network analyses could be used to develop mechanistic models involving multihost–pathogen communities. An increase in our understanding of the ecology of tick‐borne diseases across their geographic distribution will aid in the design of effective area‐wide tick control strategies aimed to diminish the burden of pathogens transmitted by ticks.
Structural Requirements of Histone Deacetylase Inhibitors: SAHA Analogs Modified on the Hydroxamic Acid
Authors: Bieliauskas Anton V. , Weerasinghe Sujith V. W. , Negmeldin Ahmed T. , Pflum Mary Kay H.
Published: April 2016

Histone deacetylase (HDAC) proteins have emerged as targets for anti‐cancer therapeutics, with several inhibitors used in the clinic, including suberoylanilide hydroxamic acid (SAHA, vorinostat). Because SAHA and many other inhibitors target all or most of the 11 human HDAC proteins, the creation of selective inhibitors has been studied intensely. Recently, inhibitors selective for HDAC1 and HDAC2 were reported where selectivity was attributed to interactions between substituents on the metal binding moiety of the inhibitor and residues in the 14‐Å internal cavity of the HDAC enzyme structure. Based on this earlier work, we synthesized and tested SAHA analogs with substituents on the hydroxamic acid metal binding moiety. The N‐substituted SAHA analogs displayed reduced potency and solubility, but greater selectivity, compared to SAHA. Docking studies suggested that the N‐substituent accesses the 14‐Å internal cavity to impart preferential inhibition of HDAC1. These studies with N‐substituted SAHA analogs are consistent with the strategy exploiting the 14‐Å internal cavity of HDAC proteins to create HDAC1/2 selective inhibitors.
Checkpoints for Autoreactive B Cells in the Peripheral Blood of Lupus Patients Assessed by Flow Cytometry
Authors: Malkiel Susan , Jeganathan Venkatesh , Wolfson Stacey , Manjarrez Orduño Nataly , Marasco Emiliano , Aranow Cynthia , Mackay Meggan , Gregersen Peter K. , Diamond Betty
Published: April 2016

Objective

Antinuclear antibodies (ANAs) are diagnostic in several autoimmune disorders, yet the failure to achieve B cell tolerance in these diseases is still poorly understood. Although secreted ANAs detected by an indirect immunofluorescence assay are the gold standard for autoreactivity, there has been no convenient assay with which to measure the frequency of circulating B cells that recognize nuclear antigens (ANA+ B cells) in patients. The aim of this study was to generate an assay to easily identify these B cells and to examine its utility in a study of autoreactive B cells in systemic lupus erythematosus (SLE).

Methods

We developed and validated a novel flow cytometry–based assay that identifies ANA+ B cells using biotinylated nuclear extracts, and utilized it to examine B cell tolerance checkpoints in peripheral blood mononuclear cells obtained from SLE patients and healthy controls.

Results

We observed progressive selection against ANA+ B cells as they matured from transitional to naive to CD27+IgD− and CD27+IgD+ memory cells in both healthy subjects and SLE patients; however, ANA+ naive B cells in SLE patients were not anergized to the same extent as in healthy individuals. We also showed that anergy induction is restored in SLE patients treated with belimumab, an inhibitor of BAFF.

Conclusion

This assay will enable studies of large populations to identify potential genetic or environmental factors affecting B cell tolerance checkpoints in healthy subjects and patients with autoimmune disease and permit monitoring of the B cell response to therapeutic interventions.
Synthesis, Structure, and Properties of the Fullerene C60 Salt of Crystal Violet, (CV+)(C60.−)⋅0.5 C6H4Cl2, which Contained Closely Packed Zigzagged C60.− Chains
Authors: Konarev Dmitri V. , Kuzmin Alexey V. , Khasanov Salavat S. , Ishikawa Manabu , Otsuka Akihiro , Yamochi Hideki , Saito Gunzi , Lyubovskaya Rimma N.
Published: April 2016

The reduction of fullerene C60 by zinc dust in the presence of crystal violet cations (CV+) yielded a deep‐blue solution, from which crystals of (CV+)(C60.−)⋅0.5 C6H4Cl2 (1) were obtained by slow mixing with n‐hexane. The salt contained isolated, closely packed zigzagged chains that were composed of C60.− radical anions with a uniform interfullerene center‐to‐center distance of 9.98 Å. In spite of the close proximity of the fullerenes, they did not dimerize, owing to spatial separation by the phenyl substituents of CV+. The room‐temperature conductivity of compound 1 was 3×10−2 S cm−1 along the fullerene chains. The salt exhibited semiconducting behavior, with an activation energy of Ea=167 meV. Spins localized on C60.− were antiferromagnetically coupled within the fullerene chains, with a Weiss temperature of −19 K without long‐range magnetic ordering down to 1.9 K.
H∞Non‐Fragile Synchronous Guaranteed Control of Uncertainty Complex Dynamic Network with Time‐Varying Delay
Authors: Luo Yi‐ping , Deng Fei , Zhou Bi‐feng , Luo Xin , Liu Huan
Published: April 2016

A kind ofH∞non‐fragile synchronization guaranteed control method is put forward for a class of uncertain time‐varying delay complex network systems with disturbance input. The network under consideration includes unknown but bounded nonlinear coupling functionsf(x) and the coupling term and node system with time‐varying delays. The nonlinear vector functionf(x) need not be differentiable but should satisfy the norm bound. A non‐fragile state feedback controller of the gain with sufficiently large regulation margin is designed. It is ensured that the parameters of the controller could still be effective under small perturbation. The sufficient conditions for the existence ofH∞synchronous non‐fragile guaranteed control of this system have been obtained by constructing a suitable Lyapunov‐Krasovskii functional, adopting matrix analysis, using the theorem of Schur complement and linear matrix inequalities (LMI). These conditions can guarantee robust asymptotic stability for each node of network with disturbance as well as achieve a prescribed robustH∞performance level. Finally, the feasibility of the designed method is verified by a numerical example.
Using stop bar detector information to determine turning movement proportions in shared lanes
Authors: Gholami Ali , Tian Zong
Published: April 2016

Turning vehicle volumes at signalized intersections are critical inputs for various transportation studies such as level of service, signal timing, and traffic safety analysis. There are various types of detectors installed at signalized intersections for control and operation. These detectors have the potential of producing volume estimates. However, it is quite a challenge to use such detectors for conducting turning movement counts in shared lanes. The purpose of this paper was to provide three methods to estimate turning movement proportions in shared lanes. These methods are characterized as flow characteristics (FC), volume and queue (VQ) length, and network equilibrium (NE). FC and VQ methods are based on the geometry of an intersection and behavior of drivers. The NE method does not depend on these factors and is purely based on detector counts from the study intersection and the downstream intersection. These methods were tested using regression and genetic programming (GP). It was found that the hourly average error ranged between 4 and 27% using linear regression and 1 to 15% using GP. A general conclusion was that the proposed methods have the potential of being applied to locations where appropriate detectors are installed for obtaining the required data. Copyright © 2016 John Wiley & Sons, Ltd.
Associations between joint attention and language in autism spectrum disorder and typical development: A systematic review and meta‐regression analysis
Authors: Bottema‐Beutel Kristen
Published: April 2016

Using a structured literature search and meta‐regression procedures, this study sought to determine whether associations between joint attention and language are moderated by group (autism spectrum disorder [ASD] vs. typical development [TD]), joint attention type (responding to joint attention [RJA] vs. other), and other study design features and participant characteristics. Studies were located using database searches, hand searches, and electronic requests for data from experts in the field. This resulted in 71 reports or datasets and 605 effect sizes, representing 1,859 participants with ASD and 1,835 TD participants. Meta‐regression was used to answer research questions regarding potential moderators of the effect sizes of interest, which were Pearson's r values quantifying the association between joint attention and language variables. In the final models, conducted separately for each language variable, effect sizes were significantly higher for the ASD group as compared to the TD group, and for RJA as compared to non‐RJA joint attention types. Approximate mental age trended toward significance for the expressive language model. Joint attention may be more tightly tied to language in children with ASD as compared to TD children because TD children exhibit joint attention at sufficient thresholds so that language development becomes untethered to variations in joint attention. Conversely, children with ASD who exhibit deficits in joint attention develop language contingent upon their joint attention abilities. Because RJA was more strongly related to language than other types of joint attention, future research should involve careful consideration of the operationalization and measurement of joint attention constructs. Autism Res 2016, 9: 1021–1035. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.
An Evaluation of the Impact of PD‐1 Pathway Blockade on Reproductive Safety of Therapeutic PD‐1 Inhibitors
Authors: Poulet Frederique M. , Wolf Jayanthi J. , Herzyk Danuta J. , DeGeorge Joseph J.
Published: April 2016

This report discusses the principles of reproductive toxicity risk assessment for biopharmaceuticals blocking the PD‐1/programmed cell death ligand 1 (PD‐L1) pathway, which have been developed for the treatment of patients with advanced malignancies. The PD‐1/PD‐L1 pathway is a T‐cell co‐inhibitory pathway that normally maintains immune tolerance to self. Its role in pregnancy is to maintain immune tolerance to the fetal allograft. In cancer patients, this signaling pathway is hijacked by some neoplasms to avoid immune destruction. PD‐1/PD‐L1‐blocking agents enhance functional activity of the target lymphocytes to eventually cause immune rejection of the tumor. A therapeutic blockade of PD‐1/PD‐L1 pathway that occurs at full target engagement provides a unique challenge to address the risk to pregnancy because disruption of the same pathway may also reduce or abrogate maternal immune tolerance to the fetal alloantigens inherited through the father. Typically, nonclinical reproductive and developmental toxicity (DART) studies in animals (rats and rabbits) with clinical drug candidates are conducted to identify potential risk in humans and to determine exposure margin for the effects on reproduction as part of the risk assessment. However, for biopharmaceuticals for which the desired mechanism of action cannot be separated from potential deleterious effects to the fetus and when the only relevant toxicology species is nonhuman primate (NHP), the risk to reproduction can be predicted by a mechanism‐based assessment using data generated from murine surrogate models as supportive information without conducting DART in NHPs. Such an approach has been used in the evaluation of pregnancy risk of anti‐PD‐1 agent, pembrolizumab, and has been demonstrated as an important alternative to performing DART studies in NHPs
Advance in phage display technology for bioanalysis
Authors: Tan Yuyu , Tian Tian , Liu Wenli , Zhu Zhi , J. Yang Chaoyong
Published: April 2016

Phage display technology has emerged as a powerful tool for target gene expression and target‐specific ligand selection. It is widely used to screen peptides, proteins and antibodies with the advantages of simplicity, high efficiency and low cost. A variety of targets, including ions, small molecules, inorganic materials, natural and biological polymers, nanostructures, cells, bacteria, and even tissues, have been demonstrated to generate specific binding ligands by phage display. Phages and target‐specific ligands screened by phage display have been widely used as affinity reagents in therapeutics, diagnostics and biosensors. In this review, comparisons of different types of phage display systems are first presented. Particularly, microfluidic‐based phage display, which enables screening with high throughput, high efficiency and integration, is highlighted. More importantly, we emphasize the advances in biosensors based on phages or phage‐derived probes, including nonlytic phages, lytic phages, peptides or proteins screened by phage display, phage assemblies and phage‐nanomaterial complexes. However, more efficient and higher throughput phage display methods are still needed to meet an explosion in demand for bioanalysis. Furthermore, screening of cyclic peptides and functional peptides will be the hotspot in bioanalysis.
Electronic properties of tetrathiafulvalene‐modified cyclic‐β‐peptide nanotube
Authors: Uji Hirotaka , Kim Hyunji , Imai Tomoya , Mitani Shota , Sugiyama Junji , Kimura Shunsaku
Published: April 2016

Cyclic tri‐β‐peptide having tetrathiafulvalene (TTF) at the side chain was synthesized to prepare a peptide nanotube aligning TTF side chains along the nanotube. The polarized light microscopic observations revealed crystallization of the cyclic peptide by the vapor diffusion method. Fourier‐transform infrared and electron diffraction measurements of the crystals clarified formation of homogeneous hydrogen bonds making a columnar structure with a layer spacing of 4.9 Å. Electronic measurements of the peptide crystals on a gold mica substrate were carried out by the current sensing AFM. The current–voltage curves showed a rectification behavior, whose profile was consistent with a metal and p‐type semiconductor junction. The p‐type property is supported by the first principle calculations, which showed the HOMO orbital delocalizing fully over the plane of the TTF ring with the energy level of −5.1 eV. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 275–282, 2016.
Review: Structure and mechanism of the dynein motor ATPase
Authors: Schmidt Helgo , Carter Andrew P.
Published: April 2016

Dyneins are multiprotein complexes that move cargo along microtubules in the minus end direction. The largest individual component of the dynein complex is the heavy chain. Its C‐terminal 3500 amino‐acid residues form the motor domain, which hydrolyses ATP in its ring of AAA+ (ATPases associated with diverse cellular activities) domains to generate the force for movement. The production of force is synchronized with cycles of microtubule binding and release, another important prerequisite for efficient motility along the microtubule. Although the large scale conformational changes that lead to force production and microtubule affinity regulation are well established, it has been largely enigmatic how ATP‐hydrolysis in the AAA+ ring causes these rearrangements. The past five years have seen a surge of high resolution information on the dynein motor domain that finally allowed unprecedented insights into this important open question. This review, part of the “ATP and GTP hydrolysis in Biology” special issue, will summarize our current understanding of the dynein motor mechanism with a special emphasis on the recently obtained crystal and EM structures. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 557–567, 2016.
Systematic review of the complications following isolated calf deep vein thrombosis
Authors: Garry J , Duke A , Labropoulos N
Published: April 2016

Background

A large number of studies have examined the potential complications of calf deep vein thrombosis (DVT). There is no consensus on when or how to treat patients to prevent these complications. This systematic review assessed the rate of proximal propagation, pulmonary embolism, major bleeding and recurrence in patients with isolated calf DVT.

Methods

Database searches of MEDLINE, the Cochrane Library, Scopus, CINAHL and Web of Science were undertaken along with extensive cross-referencing. Two independent reviewers screened the papers using stringent inclusion and exclusion criteria. Included studies were graded on six methodological standards. Data on propagation, pulmonary embolism, recurrence and major bleeding were abstracted.

Results

A total of 4261 papers were found; 15 met the inclusion criteria, including five randomized clinical trials and ten prospective cohort studies. The propagation rate to the popliteal vein or above was around 9 per cent and the rate of pulmonary embolism was close to 1·5 per cent. No studies found anticoagulant therapy to reduce the rate of adverse outcomes.

Conclusion

The literature on calf DVT is heterogeneous, limiting conclusions from data analysis. Adverse outcomes are infrequent and studies do not suggest that they are reduced by anticoagulation.
Clinical evaluation of the bed cycling test
Authors: Feil Katharina , Boettcher Nicolina , Lezius Franziska , Habs Maximilian , Hoegen Tobias , Huettemann Katrin , Muth Carolin , Eren Ozan , Schoeberl Florian , Zwergal Andreas , Bayer Otmar , Strupp Michael
Published: April 2016

Objective

Additionally to the forearm rolling test to detect mild unilateral upper limb dysfunction, the bed cycling test (BCT) for detection of mild to moderate lower limb dysfunction was developed, evaluated and compared to the leg holding test.

Methods

In a prospective observer‐blinded study, 60 patients withMRI/CT‐proven focal cerebral hemisphere lesions and a mild to moderate unilateral paresis of the lower limb (graduatedMRC3–4/5), and 60 control persons with normal imaging were examined and filmed. Nine observers blinded to the diagnosis evaluated these videos. The sensitivity, specificity and the positive and negative predictive values of the clinical tests were analyzed.

Results

The observers gave a correct evaluation ofBCTin 35.5% of all patients with focal cerebral lesions compared to 26.0% for the leg holding test. On the other hand, observers had false negative results in 29.1% of cases withBCTand 44.7% with leg holding test. In 36.7% of patients, onlyBCTwas pathological while leg holding test was unremarkable. The sensitivity of the combination of both tests was 0.68 (95%CI0.61–0.75). TheBCTis more sensitive (64.3%) than leg holding test (46.2%) while the specificity of leg holding test (85.6%) is higher than ofBCT(70.1%) to detect a cerebral lesion affecting the lower limb. The inter‐rater variability is high with no differences comparing different types of clinical experience.

Conclusions

TheBCTis a useful additional clinical bedside test to detect subtle unilateral cerebral lesions. TheBCTis easy to perform and can be added to the routine neurological examination.
Homocysteinemia and early outcome of acute ischemic stroke in elderly patients
Authors: Forti Paola , Maioli Fabiola , Arnone Giorgia , Coveri Maura , Pirazzoli Gian Luca , Zoli Marco , Procaccianti Gaetano
Published: April 2016

Objectives

Plasma total homocysteine (tHcy) is a risk factor for ischemic stroke (IS) but its relationship withISoutcome is uncertain. Moreover, previous studies underrepresented olderISpatients, although risk of both hyperhomocysteinemia andISincreases with age. We investigated whether, in elderly patients with acuteIS,tHcy measured on admission to the Stroke Unit (SU) is an independent predictor ofSUdischarge outcomes.

Materials and Methods

Data are for 644 consecutive patients aged 80.3 ± 8.7 years, admitted to an ItalianSUwith diagnosis of acuteIS. PlasmatHcy was measured onSUadmission. Investigated outcomes included mortality duringSUstay and poor functional status (modified Rankin Scale score ≥3) atSUdischarge for survivors. The association of plasmatHcy with the study outcomes was assessed using Odds Ratios (OR) and their corresponding 95% confidence intervals (95%CI) from logistic regression models adjusted for demographics, pre‐stroke features,ISseverity, and laboratory data onSUadmission (serum C‐reactive protein, serum albumin, and renal function).

Results

Median plasmatHcy was 16.7 μmol/L (interquartile range, 13.0–23.3 μmol/L). Outcome incidence was 5.3% for mortality and 49.7% for poor functional status. PlasmatHcy was unrelated to mortality in both univariate and multivariable‐adjusted analyses. Conversely, plasmatHcy was associated with poor functional status of survivors in univariate analyses (P = 0.014). Multivariable‐adjusted analyses showed that, compared to normal homocysteinemia (tHcy <16 μmol/L), risk of being discharged with poor functional status significantly increased for moderate (tHcy ≥30 mol/L) but not mild (16.0–29.9 μmol/L) hyperhomocysteinemia.

Conclusions

In elderly patients with acuteIS, high admission plasmatHcy is unrelated to mortality duringSUstay but is an independent predictor of poor functional status atSUdischarge in survivors. The association, however, is limited to patients with moderate hyperhomocysteinemia.
AKT1 and BRAF mutations in pediatric aggressive fibromatosis
Authors: Meazza Cristina , Belfiore Antonino , Busico Adele , Settanni Giulio , Paielli Nicholas , Cesana Luca , Ferrari Andrea , Chiaravalli Stefano , Massimino Maura , Gronchi Alessandro , Colombo Chiara , Pilotti Silvana , Perrone Federica
Published: April 2016

Aside from the CTNNB1 and adenomatous polyposis coli (APC) mutations, the genetic profile of pediatric aggressive fibromatosis (AF) has remained poorly characterized. The aim of this study was to shed more light on the mutational spectrum of pediatric AF, comparing it with its adult counterpart, with a view to identifying biomarkers for use as prognostic factors or new potential therapeutic targets. CTNNB1, APC, AKT1, BRAF TP53, and RET Sanger sequencing and next‐generation sequencing (NGS) with the 50‐gene Ion AmpliSeq Cancer Hotspot Panel v2 were performed on formalin‐fixed samples from 28 pediatric and 33 adult AFs. The prognostic value of CTNNB1, AKT1, and BRAF mutations in pediatric AF patients was investigated. Recurrence‐free survival (RFS) curves were estimated with the Kaplan–Meier method and statistical comparisons were drawn using the log‐rank test. In addition to the CTNNB1 mutation (64%), pediatric AF showed AKT1 (31%), BRAF (19%), and TP53 (9%) mutations, whereas only the CTNNB1 mutation was found in adult AF. The polymorphism Q472H VEGFR was identified in both pediatric (56%) and adult (40%) AF. Our results indicate that the mutational spectrum of pediatric AF is more complex than that of adult AF, with multiple gene mutations involving not only CTNNB1 but also AKT1 and BRAF. This intriguing finding may have clinical implications and warrants further investigations.
Role of Facilitated Transport Membranes and Composite Membranes for Efficient CO2 Capture – A Review
Authors: Rafiq Sikander , Deng Liyuan , Hägg May‐Britt
Published: April 2016

CO2 emission from anthropogenic sources has raised global environmental concerns, and efficient reduction of these greenhouse gas emissions by capturing CO2 is recognized world‐wide as very important along with the implementation of new green energy technology. Membrane technology is considered to be one of the efficient techniques to be used for CO2 capture. Among different types of membranes, mixed matrix membranes and facilitated transport membranes have gained much interest in recent years due to documented high CO2 permeance through these membranes, especially when the gas is humid as is the case for flue gas from combustion. In the current review, a comprehensive discussion is focused on the development of hybrid membranes involving the selection of the fixed site carrier (FSC) membranes and the interaction of nanosilica‐particles in a polymer membrane for efficient CO2 capture. Other facilitated transport membranes and mixed matrix membranes are also briefly discussed.
Hemodynamic changes in systolic and diastolic function during isoproterenol challenge predicts symptomatic response to myectomy in hypertrophic cardiomyopathy with labile obstruction
Authors: Prasad Megha , Geske Jeffrey B. , Sorajja Paul , Ommen Steve R. , Schaff Hartzell V. , Gersh Bernard J. , Nishimura Rick A.
Published: April 2016

Objectives

We aimed to assess the utility of changes in systolic and diastolic function by isoproterenol challenge in predicting symptom resolution post‐myectomy in selected patients with hypertrophic cardiomyopathy (HCM) and labile obstruction.

Background

In a subset of symptomatic HCM patients without resting/provocable obstruction on noninvasive assessment, isoproterenol challenge during hemodynamic catheterization may elicit labile left ventricular outflow tract (LVOT) obstruction, and demonstrate the effect of obstruction on diastolic function. These changes may determine whether patients achieve complete symptom resolution post‐myectomy.

Methods

Between February 2003 and April 2009, 18 symptomatic HCM patients without LVOT obstruction on noninvasive testing underwent isoproterenol provocation and septal myectomy due to presence of provocable gradient and were followed for 4 (IQR 3–7) years.

Results

Thirteen (72.2%) had complete symptom resolution, while 5 (27.8%) had improved, but persistent symptoms. Those with provoked gradient >100 mm Hg or increase in left atrial pressure (LAP) with isoproterenol had symptom resolution.

Conclusions

Symptomatic HCM patients without LVOT gradient on noninvasive testing may demonstrate labile obstruction with isoproterenol. With isoproterenol, patients with high LVOT gradient or increase in LAP concomitant with an increase in gradient achieved complete symptom resolution post‐myectomy. Thus, improved diastolic filling as well as outflow gradient production in patients with HCM may predict symptom response to myectomy. © 2016 Wiley Periodicals, Inc.
Promotion of Hydrogen Desorption from Palladium Surfaces by Fluoropolymer Coating
Authors: Delmelle Renaud , Ngene Peter , Dam Bernard , Bleiner Davide , Borgschulte Andreas
Published: April 2016

The catalytic activity of Pd surfaces towards hydrogen desorption was significantly improved by a nanometer‐thin polytetrafluoroethylene (PTFE) layer, as shown by an enhancement in the permeability of a Pd membrane coated on the permeate side. The origin of this effect was found to be due to a lowering of the barrier for hydrogen desorption, as evidenced by a change in the rate‐limiting mechanism of hydrogen permeation through the membrane from desorption (un‐coated) to diffusion controlled. In situ X‐ray photoelectron spectroscopy (XPS) revealed the electronic structure of the sputtered PTFE. Apart from C–Fn subunits (n=1, 2, 3), we found that nonsaturated carbon atoms became hydrogenated during hydrogen permeation, which was indicative of an interaction between Pd and PTFE. This interaction was weak; no Pd−F bonds were formed. We thus attributed the effect to an increase in the hydrophobicity of the surface by the porous PTFE layer and to a promoter effect of hydrogen desorption as a result of electrostatic interactions between chemisorbed hydrogen and physisorbed PTFE.
Design and Optimization of the Methanol‐to‐Olefin Process. Part I: Steady‐State Design and Optimization
Authors: Yu Bor‐Yih , Chien I‐Lung
Published: April 2016

The steady‐state design and optimization for a methanol‐to‐olefin (MTO) process is studied. The MTO process is a novel route for light olefin production, especially ethylene and propylene. Comparing with the traditional way to produce olefins by steam cracking, this process offers benefits such as a more flexible range of ethylene‐to‐propylene ratio, higher selectivity toward light olefin, and mild reaction conditions. The design of the overall MTO process is divided into four sections, namely, reaction section, conditioning section, first separation section, and second separation section. After the design of each sub‐part, optimization is performed, in which the design and operating variables are thoroughly investigated. By rigorous simulation, a more economically competitive design flowsheet of the overall MTO process is proposed.
Enzyme Mimics: Advances and Applications
Authors: Kuah Evelyn , Toh Seraphina , Yee Jessica , Ma Qian , Gao Zhiqiang
Published: April 2016

Enzyme mimics or artificial enzymes are a class of catalysts that have been actively pursued for decades and have heralded much interest as potentially viable alternatives to natural enzymes. Aside from having catalytic activities similar to their natural counterparts, enzyme mimics have the desired advantages of tunable structures and catalytic efficiencies, excellent tolerance to experimental conditions, lower cost, and purely synthetic routes to their preparation. Although still in the midst of development, impressive advances have already been made. Enzyme mimics have shown immense potential in the catalysis of a wide range of chemical and biological reactions, the development of chemical and biological sensing and anti‐biofouling systems, and the production of pharmaceuticals and clean fuels. This Review concerns the development of various types of enzyme mimics, namely polymeric and dendrimeric, supramolecular, nanoparticulate and proteinic enzyme mimics, with an emphasis on their synthesis, catalytic properties and technical applications. It provides an introduction to enzyme mimics and a comprehensive summary of the advances and current standings of their applications, and seeks to inspire researchers to perfect the design and synthesis of enzyme mimics and to tailor their functionality for a much wider range of applications.
Construction of Giant‐Spin Hamiltonians from Many‐Spin Hamiltonians by Third‐Order Perturbation Theory and Application to an Fe3Cr Single‐Molecule Magnet
Authors: Tabrizi Shadan Ghassemi , Arbuznikov Alexei V. , Kaupp Martin
Published: April 2016

A general giant‐spin Hamiltonian (GSH) describing an effective spin multiplet of an exchange‐coupled metal cluster with dominant Heisenberg interactions was derived from a many‐spin Hamiltonian (MSH) by treating anisotropic interactions at the third order of perturbation theory. Going beyond the existing second‐order perturbation treatment allows irreducible tensor operators of rank six (or corresponding Stevens operator equivalents) in the GSH to be obtained. Such terms were found to be of crucial importance for the fitting of high‐field EPR spectra of a number of single‐molecule magnets (SMMs). Also, recent magnetization measurements on trigonal and tetragonal SMMs have found the inclusion of such high‐rank axial and transverse terms to be necessary to account for experimental data in terms of giant‐spin models. While mixing of spin multiplets by local zero‐field splitting interactions was identified as the major origin of these contributions to the GSH, a direct and efficient microscopic explanation had been lacking. The third‐order approach developed in this work is used to illustrate the mapping of an MSH onto a GSH for an
trigonal Fe3Cr complex that was recently investigated by high‐field EPR spectroscopy. Comparisons between MSH and GSH consider the simulation of EPR data with both Hamiltonians, as well as locations of diabolical points (conical intersections) in magnetic‐field space. The results question the ability of present high‐field EPR techniques to determine high‐rank zero‐field splitting terms uniquely, and lead to a revision of the experimental GSH parameters of the Fe3Cr SMM. Indeed, a bidirectional mapping between MSH and GSH effectively constrains the number of free parameters in the GSH. This notion may in the future facilitate spectral fitting for highly symmetric SMMs.
Two‐Photon Excitation of a Plasmonic Nanoswitch Monitored by Single‐Molecule Fluorescence Microscopy
Authors: Impellizzeri Stefania , Simoncelli Sabrina , Hodgson Gregory K. , Lanterna Anabel E. , McTiernan Christopher D. , Raymo Françisco M. , Aramendia Pedro F. , Scaiano Juan. C.
Published: April 2016

Visible‐light excitation of the surface plasmon band of silver nanoplates can effectively localize and concentrate the incident electromagnetic field enhancing the photochemical performance of organic molecules. Herein, the first single‐molecule study of the plasmon‐assisted isomerization of a photochrome‐fluorophore dyad, designed to switch between a nonfluorescent and a fluorescent state in response to the photochromic transformation, is reported. The photochemistry of the switchable assembly, consisting of a photochromic benzooxazine chemically conjugated to a coumarin moiety, is examined in real time with total internal reflection fluorescence microscopy in the presence of silver nanoplates excited with a 633 nm laser. The metallic nanostructures significantly enhance the visible light‐induced performance of the photoconversion, which normally requires ultraviolet excitation. The resulting ring‐open isomer is strongly fluorescent and can also be excited at 633 nm. These stochastic emission events are used to monitor photochromic activation and show quadratic dependence on incident power. The utilization of a single laser wavelength for both photochromic activation and excitation effectively mimics a pseudo two‐colours system.
Highly Enantioselective Fluorescent Recognition of Both Unfunctionalized and Functionalized Chiral Amines by a Facile Amide Formation from a Perfluoroalkyl Ketone
Authors: Wang Chao , Anbaei Parastoo , Pu Lin
Published: April 2016

The H8BINOL‐based perfluoroalkyl ketone (S)‐2 is found to exhibit highly enantioselective fluorescent enhancements toward both unfunctionalized and functionalized chiral amines. It greatly expands the substrate scope of the corresponding BINOL‐based sensor. A dramatic solvent effect was observed for the reaction of the amines with compound (S)‐2. In DMF, cleavage of the perfluoroalkyl group of compound (S)‐2 to form amides was observed but not in other solvents, such as methylene chloride, chloroform, THF, hexane, and perfluorohexane. Thus, the addition of another solvent, such as THF, can effectively quench the reaction of compound (S)‐2 with amines in DMF to allow stable fluorescent measurement. This is the first example that the formation of strong amide bonds under very mild conditions is used for the enantioselective recognition of chiral amines. The mechanism of the reaction of compound (S)‐2 with chiral amines is investigated by using various analytical methods including mass spectrometry as well as NMR and UV/Vis absorption spectroscopy.
A Solvent Switch for the Stabilization of Multiple Hemiacetals on an Inorganic Platform: Role of Supramolecular Interactions
Authors: Kalita Alok Ch. , Gupta Sandeep K. , Murugavel Ramaswamy
Published: April 2016

Reaction of Zn(OAc)2⋅2 H2O with 2,6‐diisopropylphenyl phosphate (dippH2) in the presence of pyridine‐4‐carboxaldehyde (Py‐4‐CHO) in methanol resulted in the isolation of a tetrameric zinc phosphate cluster [Zn(dipp)(Py‐4‐CH(OH)(OMe))]4⋅4 MeOH (1) with four hemiacetal moieties stabilized on the double‐4‐ring inorganic cubane cluster. The change of solvent from methanol to acetonitrile leads to the formation of [Zn(dipp)(Py‐4‐CHO)]4 (2), in which the coordinated Py‐4‐CHO retains its aldehydic form. Dissolution of 1 in CD3CN readily converts it to the aldehydic form and yields 2. Similarly 2, which exists in the aldehyde form in CD3CN, readily converts to the hemiacetal form in CD3OD/CH3OH. Compound 1 is an unprecedented example in which four hemiacetals have been stabilized on a single molecule in the solid state retaining its stability in solution as revealed by its 1H NMR spectrum in CD3OD. The solution stability of 1 and 2 has further been confirmed by ESI‐MS studies. To generalize the stabilization of multiple hemiacetals on a single double‐four‐ring platform, pyridine‐2‐carboxaldehyde (Py‐2‐CHO) was used as the auxiliary ligand in the reaction between zinc acetate and dippH2, leading to isolation of [Zn(dipp)(Py‐2‐CH(OH)(OMe))]4 (3). Understandably, recrystallization of 3 from acetonitrile yields the parent aldehydic form, [Zn(dipp)(Py‐2‐CHO)]4 (4). Single‐crystal X‐ray diffraction studies reveal that supramolecular bonding, aided by hydrogen‐bonding interactions involving the hemiacetal functionalities (C−OH, C−OMe, and C−H), are responsible for the observed stabilization. The hemiacetal/aldehyde groups in 1 and 2 readily react with p‐toluidine, 2,6‐dimethylaniline, and 4‐bromoaniline to yield the corresponding tetra‐Schiff base ligands, [Zn(dipp)(L)]4 (L=4‐methyl‐N‐(pyridin‐4‐ylmethylidene)aniline (5), 2,6‐dimethyl‐N‐(pyridin‐4‐ylmethylene)‐aniline (6), and 4‐bromo‐N‐(pyridin‐4‐ylmethylene)aniline (7)). Isolation of 5–7 opens up further possibilities of using 1 and 2 as new supramolecular synthons and ligands.