bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐dimensional shear wave elastography of the perirenal fat: Can sticky fat be predicted?
Authors: Çamlıdağ İlkay , Öner Süleyman , Özden Ender
Published: December 2018

Purpose

To evaluate whether two‐dimensional (2D) shear wave elastography (SWE) can predict the presence of perirenal sticky fat (PSF) by showing increased perirenal fat stiffness.

Methods

We prospectively enrolled 28 patients with 31 renal tumors and 10 donor cases. Conventional renal ultrasound (US) and 2D‐SWE examination of the perirenal fat were performed. Patient age, gender, body mass index (BMI), largest mass size, PF shear wave velocity (SWV) on both sides were recorded. During surgery, presence of PSF and perirenal fat dissection time (PFDT) were recorded.

Results

Twenty three renal masses were malignant and eight were benign. There were 13 clear cell carcinomas and 10 nonclear cell carcinomas. Eight patients had PSF. Mean PFDT was 13 minutes. PFDT and BMI were significantly increased in the PSF group (p < .05). No statistically significant differences were found in SWVs in patients with and without PSF. There were no significant differences with regard to SWVs between donor cases and patients, tumor side and nontumor side, benign masses and malignant masses, clear cell and nonclear cell tumors. No significant correlations were detected between SWVs and PFDT, mass size, Fuhrman grade and BMI (p > .05).

Conclusion

2D‐SWE cannot detect PSF.
Usage of automation tools in systematic reviews
Authors: van Altena A.J. , Spijker R. , Olabarriaga S.D.
Published: December 2018

Systematic reviews are a cornerstone of today's evidence‐informed decision making. With the rapid expansion of questions to be addressed and scientific information produced, there is a growing workload on reviewers, making the current practice unsustainable without the aid of automation tools. While many automation tools have been developed and are available, uptake seems to be lagging. For this reason, we set out to investigate the current level of uptake and what the potential barriers and facilitators are for the adoption of automation tools in systematic reviews. We deployed surveys among systematic reviewers that gathered information on tool uptake, demographics, systematic review characteristics, and barriers and facilitators for uptake. Systematic reviewers from multiple domains were targeted during recruitment; however, responders were predominantly from the biomedical sciences. We found that automation tools are currently not widely used among the participants. When tools are used, participants mostly learn about them from their environment, for example, through colleagues, peers, or organization. Tools are often chosen on the basis of user experience, either by own experience or from colleagues or peers. Lastly, licensing, steep learning curve, lack of support, and mismatch to workflow are often reported by participants as relevant barriers. While conclusions can only be drawn for the biomedical field, our work provides evidence and confirms the conclusions and recommendations of previous work, which was based on expert opinions. Furthermore, our study highlights the importance that organizations and best practices in a field can have for the uptake of automation tools for systematic reviews.
Three‐Dimensional Subharmonic Aided Pressure Estimation for Assessing Arterial Plaques in a Rabbit Model
Authors: Nam Kibo , Liu Ji‐Bin , Eisenbrey John R. , Stanczak Maria , Machado Priscilla , Li Jingzhi , Li Zhaojun , Wei Ying , Forsberg Flemming
Published: December 2018

Objectives

To investigate 3‐dimensional subharmonic aided pressure estimation (SHAPE) for measuring intraplaque pressure and the pressure gradient across the plaque cap as novel biomarkers for potentially predicting plaque vulnerability.

Methods

Twenty‐seven rabbits received a high‐cholesterol diet for 2 weeks before a balloon catheter injury to denude the endothelium of the aorta, followed by 8 to 10 weeks of the high‐cholesterol diet to create arteriosclerotic plaques. SHAPE imagings of the resulting plaques were performed 12, 16, and 20 weeks after injury using a LOGIQ 9 scanner with a 4D10L probe (GE Healthcare, Milwaukee, WI) before and during an infusion of Definity (Lantheus Medical Imaging, North Billerica, MA) and Sonazoid (GE Healthcare, Oslo, Norway). The ratios of the maximum subharmonic magnitudes at baseline and during the infusion were correlated with the intraplaque pressure and pressure gradient across the plaque cap obtained from direct measurements.

Results

Ten rabbits died prematurely after the balloon injury procedure or due to toxicity from the high‐cholesterol diet, whereas 2 rabbits were excluded for other conditions. Five rabbits were scanned in the 12‐, 16‐, and 20‐week groups, respectively. Even after 20 weeks, the plaques that developed were very small (mean ± SD, 0.9 ± 0.4 × 0.14 ± 0.05 cm). Definity performed better than Sonazoid in this application but still only achieved a moderate correlation with pressure across the plaque cap (Definity, r = –0.40; Sonazoid, r = 0.22) and intraplaque pressure (Definity, r = –0.19; Sonazoid, r = –0.11).

Conclusions

Initial findings from plaque pressure estimation using 3‐dimensional SHAPE technique showed only moderate correlations with reference standards, but that may be have been due to weaknesses in the animal model studied.
Can Ultrasound in Early Gestation Improve Visualization of Fetal Cardiac Structures in Obese Pregnant Women?
Authors: Majeed Amara , Abuhamad Alfred , Romary Letty , Sinkovskaya Elena
Published: December 2018

Objectives

To determine whether ultrasound (US) imaging of obese pregnant women in early gestation improves fetal cardiac visualization.

Methods

We report a prospective longitudinal trial comparing late first‐ and early second‐trimester US to traditional second‐trimester US for fetal cardiac screening in maternal obesity. All study participants received US for fetal cardiac screening at a gestational age of 13 weeks to 15 weeks 6 days using a transvaginal or transabdominal approach (UST1). All patients also underwent a traditional transabdominal examination at 20 to 22 weeks (UST2). If UST2 failed to complete the cardiac visualization, a follow up examination (second UST2) was performed 2 to 4 weeks later. Imaging was considered complete if the visceral situs, 4 chambers, outflow tracts, and 3 vessels were visualized. The completion rates between UST1 and UST2 were the primary outcomes. A power analysis (85%) and sample size calculation (n = 145) were performed.

Results

A total of 152 pregnancies met study criteria. Completion rates of cardiac screening were 77% for UST1 and 70% for UST2 (P = .143). This comparison reached statistical significance in patients with a body mass index of greater than 40 kg/m2 (UST1 [69%] versus UST2 [38%]; P = .001). Sixty‐two percent of patients with a body mass index of greater than 40 kg/m2 required second UST2. The highest fetal cardiac screening completion rate was achieved when UST1 was combined with UST2 (96.1%). In 1 fetus, congenital heart disease was detected at UST1 and later confirmed.

Conclusions

This study represents the largest prospective trial assessing early‐gestation US for fetal cardiac screening in the setting of maternal obesity. In obese pregnancies, the addition of early‐gestation US to the 20‐ to 22‐week US substantially improves the visualization of fetal cardiac anatomy.
A positive quantization on type I locally compact groups
Authors: Măntoiu Marius
Published: December 2018

Let be a unimodular type I second countable locally compact group and let be its unitary dual. Motivated by a recent pseudo‐differential calculus, we develop a positive Berezin‐type quantization with operator‐valued symbols defined on .
Co‐occurrence of pederin‐producing and Wolbachia endobacteria in Paederus fuscipes Curtis, 1840 (Coleoptera: Staphilinidae) and its evolutionary consequences
Authors: Maleki‐Ravasan Naseh , Akhavan Niloofar , Raz Abbasali , Jafari Mahmood , Zakeri Sedigheh , Dinparast Djadid Navid
Published: December 2018

The dual occurrence of Pseudomonas‐like and Wolbachia endobacteria has not been investigated in the Pederus beetles yet. We investigated pederin‐producing bacteria (PPB) infection in Paederus fuscipes specimens from the southern margins of the Caspian Sea by designed genus‐specific (OprF) and species‐specific (16S rRNA) primers. Wolbachia infection was studied through a nested‐PCR assay of Wolbachia surface protein (wsp) gene. Of the 125 analyzed beetles, 42 females (82.35%) and 15 males (20.27%) were positive to PPB infection; this is the first study reporting male P. fuscipes infection to PPB. Wolbachia infection was found in 45 female (88.23%) and 50 male (67.57%) analyzed beetles. Surprisingly, a number of 36 females (70.59%) and 13 males (17.57%) were found to be infected with both PPB and Wolbachia endosymbionts. In general, population infection rates to PPB and Wolbachia were determined to be 45.6% and 76%, respectively. The infection rates of female beetles to PPB and PPB‐Wolbachia were significantly higher than males. In Paederus species, only female beetles shelter PPB and the discovery of this bacterium in adult males may reflect their cannibalistic behavior on the contaminated stages. Phylogenetic analysis showed that the sequences of OprF gene were unique among Pseudomonas spp.; however, sequences of 16S rRNA gene were related to the PPB of Pederus species. The co‐occurrence and random distribution of these endobacteria may imply putative tripartite interactions among PPB, Wolbachia, and Paederus. In order to elucidate these possible tripartite interactions, further studies are required even at gender level.
A clinical multi‐center registry study on digital nerve repair using a biodegradable nerve conduit of PGA with external and internal collagen scaffolding
Authors: Kusuhara Hirohisa , Hirase Yuichi , Isogai Noritaka , Sueyoshi Yu
Published: December 2018

Background

In this study, we evaluated the clinical efficacy of a biodegradable nerve conduit constructed of polyglycolic acid (PGA) tube with external and internal collagen scaffolding for digital nerve repair.

Patients and methods

A multi‐center registry study was conducted in 11 locations between July 2013 and May 2016. Multiple mechanisms of injury included clean‐cut (12 patients), crush (5 patients), and avulsion (3 patients) types of injuries. These patients underwent nerve repair with a biodegradable nerve conduit, with 9 patients having a primary repair and 11 patients having delayed repair. Average nerve gap was 16.7 mm (range: 1–50 mm). An average of 13 months follow‐up (range: 12–15 months) was available including sensory assessments.

Results

Improved s2PD was found with less severe injury as in clean‐cut (7.5 ± 1.5 mm), which was statistically significant in comparison to those in crush (9.8 ± 1.9 mm, P = .0384) and in avulsion (10.7 ± 4.7 mm, P = .0013) type injuries. A meaningful recovery (S3+ or S4) was observed in 90% of the 20 digital nerve repairs with a biodegradable nerve conduit of PGA with external and internal collagen scaffolding. Avulsion injuries had significantly lower levels of meaningful recovery (67%) in comparison to those of clean‐cut (P = .0291) and crush (P = .0486) types of injury. No adverse effects were reported postoperatively.

Conclusion

These results indicate that a biodegradable nerve conduit of PGA with external and internal collagen scaffolding is suitable for digital nerve repair of short nerve gaps with high levels of sensory recovery as measured by two‐point discrimination.
Bifurcations and spatiotemporal patterns in a ratio‐dependent diffusive Holling‐Tanner system with time delay
Authors: An Qi , Jiang Weihua
Published: December 2018

In this paper, we concentrate on the spatiotemporal patterns of a delayed reaction‐diffusion Holling‐Tanner model with Neumann boundary conditions. In particular, the time delay that is incorporated in the negative feedback of the predator density is considered as one of the principal factors to affect the dynamic behavior. Firstly, a global Turing bifurcation theorem for τ  =  0 and a local Turing bifurcation theorem for τ > 0 are given. Then, further considering the degenerated situation, we derive the existence of Bogdanov‐Takens bifurcation and Turing‐Hopf bifurcation. The normal form method is used to study the explicit dynamics near the Turing‐Hopf singularity. It is shown that a pair of stable nonconstant steady states (stripe patterns) and a pair of stable spatially inhomogeneous periodic solutions (spot patterns) could be bifurcated from a positive equilibrium. Moreover, the Turing‐Turing‐Hopf–type spatiotemporal patterns, that is, a subharmonic phenomenon with two spatial wave numbers and one temporal frequency, are also found and explained theoretically. Our results imply that the interaction of Turing and Hopf instabilities can be considered as the simplest mechanism for the appearance of complex spatiotemporal dynamics.
Mapping water exchange across the blood–brain barrier using 3D diffusion‐prepared arterial spin labeled perfusion MRI
Authors: Shao Xingfeng , Ma Samantha J. , Casey Marlene , D’Orazio Lina , Ringman John M. , Wang Danny J.J.
Published: December 2018

Purpose

To present a novel MR pulse sequence and modeling algorithm to quantify the water exchange rate (kw) across the blood–brain barrier (BBB) without contrast, and to evaluate its clinical utility in a cohort of elderly subjects at risk of cerebral small vessel disease (SVD).

Methods

A diffusion preparation module with spoiling of non–Carr‐Purcell‐Meiboom‐Gill signals was integrated with pseudo‐continuous arterial spin labeling (pCASL) and 3D gradient and spin echo (GRASE) readout. The tissue/capillary fraction of the arterial spin labeling (ASL) signal was separated by appropriate diffusion weighting (b = 50 s/mm2). kw was quantified using a single‐pass approximation (SPA) model with total generalized variation (TGV) regularization. Nineteen elderly subjects were recruited and underwent 2 MRIs to evaluate the reproducibility of the proposed technique. Correlation analysis was performed between kw and vascular risk factors, Clinical Dementia Rating (CDR) scale, neurocognitive assessments, and white matter hyperintensity (WMH).

Results

The capillary/tissue fraction of ASL signal can be reliably differentiated with the diffusion weighting of b = 50 s/mm2, given ~100‐fold difference between the (pseudo‐)diffusion coefficients of the 2 compartments. Good reproducibility of kw measurements (intraclass correlation coefficient = 0.75) was achieved. Average kw was 105.0 ± 20.6, 109.6 ± 18.9, and 94.1 ± 19.6 min–1 for whole brain, gray and white matter. kw was increased by 28.2%/19.5% in subjects with diabetes/hypercholesterolemia. Significant correlations between kw and vascular risk factors, CDR, executive/memory function, and the Fazekas scale of WMH were observed.

Conclusion

A diffusion prepared 3D GRASE pCASL sequence with TGV regularized SPA modeling was proposed to measure BBB water permeability noninvasively with good reproducibility. kw may serve as an imaging marker of cerebral SVD and associated cognitive impairment.
Numerical solution of nonlinear partial quadratic integro‐differential equations of fractional order via hybrid of block‐pulse and parabolic functions
Authors: Mirzaee Farshid , Alipour Sahar
Published: December 2018

In this paper, an effective numerical approach based on a new two‐dimensional hybrid of parabolic and block‐pulse functions (2D‐PBPFs) is presented for solving nonlinear partial quadratic integro‐differential equations of fractional order. Our approach is based on 2D‐PBPFs operational matrix method together with the fractional integral operator, described in the Riemann–Liouville sense. The main characteristic behind this approach is to reduce such problems to those of solving systems of algebraic equations, which greatly simplifies the problem. By using Newton's iterative method, this system is solved, and the solution of fractional nonlinear partial quadratic integro‐differential equations is achieved. Convergence analysis and an error estimate associated with the proposed method is obtained, and it is proved that the numerical convergence order of the suggested numerical method is O(h3). The validity and applicability of the method are demonstrated by solving three numerical examples. Numerical examples are presented in the form of tables and graphs to make comparisons with the exact solutions much easier.
Polymeric fibers and microporous films by photo‐crosslinking of triphenylene‐derived liquid crystals
Authors: Hirose Takuji , Xu Zhe , Kikuchi Yuka , Fukushima Masahito , Kawamura Kengo , Kaguchi Yosuke , Kodama Koichi , Yasutake Mikio
Published: December 2018

Two series of photoreactive discotic liquid crystals consisting of a triphenylene core and six cinnamate units with one (TPC1
n) or two (TPC2
n) n‐alkoxy groups (C
nH2n+1O; n = 10–14), respectively, as peripheral groups are synthesized. Both of them are polymerized into fibers up to 2 mm long by UV irradiation in liquid paraffin in the columnar LC temperature ranges. The fiber structures seem to be preconstructed in liquid paraffin. In addition, TPC2
n are shown to form microporous films up to 15 μm in diameter by simply casting the solutions of some solvents followed by drying for several minutes in air at room temperature. Photoirradiation of the films in the LC temperature range converts them to polymeric ones while preserving the microporous and hexagonally ordered structure. From comparison with TPC1
n and the hydrogenated derivative of TPC2
12, the porous film‐forming property is suggested to result from the combination of the double bond of the cinnamoyl group and the two long alkoxy chains on the phenyl ring. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 605–612
Enhanced Wide‐Angle Energy Conversion Using Structure‐Tunable Waveguide Arrays as Encapsulation Materials for Silicon Solar Cells
Authors: Biria Saeid , Chen Fu‐Hao , Hosein Ian D.
Published: December 2018

The authors report on the enhancement in optical energy conversion in silicon solar cells encapsulated with a polymer film comprising of waveguide array structures. The structures are fabricated through light‐induced self‐writing with periodic arrangements of optical beams transmitted through a binary component photopolymer, wherein a periodic core‐cladding architecture is produced. The size, spacing, and arrangement of the cores are varied through the size and arrangement of the optical beams via photomask design. A range of waveguide array structures are produced using different masks and component weight fractions. External quantum efficiency (EQE) measurements reveal structures that provide the greatest enhancement for normal and non‐normal incidence irradiation, the latter for which reveals wide‐angle light capture and conversion. Encapsulated solar cells yield an approximate 10% enhancement in EQE and a 20% increase in the short circuit current, up to an incident angle of 40°, as compared to uniform encapsulants. The experimental results are corroborated by beam propagation simulations that show the spatial confinement of transmitted optical energy is the main effect that increases conversion efficiency. Principles that establish a structure‐property‐performance relationship are discussed, toward rational materials processing to increase energy conversion.
A Naphthalimide‐Based Fluorescent Turn‐On Sensor for the Selective Detection of Diethyl Chlorophosphate
Authors: Du Bin , Zhang Fa‐Heng , Cao Wei , Wang Pu‐Hong , Li Zhi‐Jun , Ding Zhi‐Jun
Published: December 2018

A naphthalimide derivative, named 4‐(2‐aminophenoxy)‐N‐(2‐ethylhexyl)‐naphthalimide (AEN), was synthesized and characterized by NMR and ESI‐MS. The photophysical behaviors of AEN toward diethyl chlorophosphate (DCP) were investigated by fluorescence spectrometry. Moreover, the detection mechanism of AEN for DCP was evaluated by 1H, 31P NMR and ESI‐MS spectroscopy. These results show that the fluorescence intensity of AEN significantly increased with the augment of DCP concentration. No obvious interference with the DCP detection was observed in the presence of other common solvents (e. g. tetrahydrofuran, dimethyl sulfoxide, n‐hexane, N,N‐dimethylformamide, and isopropanol), phosphorus‐containing reagents (e. g. dimethyl methylphosphonate, and triethyl phosphate), brominated compounds (1‐bromobutane) and chlorinated compounds (e. g. 1,2‐dichloroethane, chlorobenzene, carbon tetrachloride), indicating that AEN possesses satisfactory selectivity and sensitivity for the detection of DCP.
Luminescence, Dye Degradation and DNA Binding Properties of a Dinuclear Nona‐Coordinated Y(III) Complex
Authors: Pathak Sayantan , Ghosh Mithun K. , Ghorai Tanmay K.
Published: December 2018

In this study, a dinuclear nona‐coordinated acetate bridged [Y2(μ3‐CH3COO)2(CH3COO)4(OH)4]. 4H2O (1) complex was synthesized and its luminescence, dye degradation and DNA binding properties were evaluated. The complex 1 belonged to triclinic crystal system with P‐1 space group and the structure consisted of [YIII2(μ3‐OR)2(μ‐OR)4(OH)4] asymmetric “butterfly” units, where R is the rest of a CH3CO2 group linked together in the form of a loop by alternating anti, anti (μ3‐O2CMe)2 and (μ‐O2CMe)2 units attached with the Y wingtip atoms. Interestingly, the co‐ordination number of each Y atom was nine in crystal 1, which was unprecedented and the oxidation states of both the Y atoms were +3 and confirmed by BVS calculation. The inter‐ and intra‐molecular H‐bonding in the molecule gave rise to a layer type of structure. The luminescence property of the Complex 1 reveals that the emission band arises at 279 nm which indicates the Complex 1 had efficient luminescence activity. The Complex 1 exhibited an exciting performance towards degradation of a model pollutant methylene blue and also showed good DNA‐ binding ability.
Synergetic Effect of Iron‐Doped Acidic Multi‐Walled Carbon Nanotubes in the Synthesis of Diverse Substituted Five‐Membered Heterocyclic Compounds
Authors: Sharghi Hashem , Mozaffari Mozhdeh , Aboonajmi Jasem , Doroodmand Mohammad Mahdi , Shiri Pezhman , Aberi Mahdi
Published: December 2018

Iron‐doped acidic multi‐walled carbon nanotubes (Fe@acidic‐MWCNs) were synthesized using the chemical vapor deposition (CVD) process in the presence of acetylene and ferrocene as the sources of carbon and iron nanoparticles, respectively. The Fe@acidic‐MWCNs was fully characterized by inductively coupled plasma (ICP), X‐ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman, and FT‐IR analysis. In continuation, the synergetic effect of iron nanoparticles and acidic groups of the Fe@acidic‐MWCNs was studied through the synthesis of substituted five‐membered heterocyclic compounds including 2‐substituted benzimidazoles, 2‐substituted benzothiazoles, 2‐substituted benzoxazoles, and 1‐substituted tetrazoles. Moreover, the 2‐substituted benzimidazoles were investigated by two different methods. In general, Fe@acidic‐MWCNs catalyst showed good to excellent catalytic activity. Finally, the Fe@acidic‐MWCNs catalyst displayed a high reusability and stability in the synthesis of 3 a, 5 a, 7 a, 9 a, and 11 a.
Synthesis, In Vitro Biological Evaluation and In Silico Studies of Some New Heterocyclic Schiff Bases
Authors: Arif Rizwan , Amaduddin  , Ahmed Sarfraz , Ahmed Saami , Abid Mohammad , Rahisuddin
Published: December 2018

2‐Hydroxy‐naphthaldehyde based heterocyclic Schiff base derivatives (1 a‐1 h) were prepared and characterized by multi‐spectroscopic techniques and elemental analysis. Antibacterial activity of all the compounds was tested against Streptococcus pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumoniae and Escherichia coli bacterial strains. The antifungal potential of the synthesized compounds was also tested against three Candida strains (Candida albicans, Candida glabrata and Candida tropicalis). In the antibacterial activity, the compounds showed high MIC values and thus found less potent against all the tested bacterial strains. Interestingly, compounds 1 b and 1 c exhibited significant activity with MIC 125 μg/ml against all the tested fungal strains. Hemolytic assay against human RBCs revealed that compounds 1 b and 1 c showed less toxicity than the standard drug fluconazole at each tested concentration (25‐1000 μg/ml). In growth kinetics studies, compounds 1 b and 1 c significantly inhibited the growth of Candida cells at 2MIC and MIC concentrations. The interaction ability of lead compounds (1 b and 1 c) with Ct–DNA was carried out by absorption, fluorescence, hydrodynamic, cyclic voltammetery measurements and circular dichroism. Results suggested that compound 1 b and 1 c bind to Ct–DNA via an intercalative mode supported by molecular docking studies. The antioxidant potential of heterocyclic derivatives 1 b and 1 c was estimated by DPPH free radical and hydrogen peroxide assay which confirm that compounds exhibited significant antioxidant activity.
First Principles Investigation and Hirshfeld Surface Analysis of Conformational Polymorphism of 3‐Chloroisonicotinic Acid
Authors: Yang Fang‐Ling , Wang Rui , Yang Xing , Lu Ka , Yang Xiao‐Shan , Yan Chao‐Xian , Zhou Pan‐Pan , Yang Zhaoyong
Published: December 2018

The crystallization of 3‐chloroisonicotinic acid (3‐CINA) can lead to three crystal forms (I, II and III), but 3‐CINA in each form has different conformation. The three crystal forms have different lattice energies. The intermolecular interactions in the molecular pairs involving the conformer in each crystal were evaluated, it is found that the sum of these intermolecular interaction energies in each crystal has a linear relationship with the corresponding lattice energy. QTAIM analyses for the intermolecular interactions of molecular pairs correspond to Hirshfeld surface analyses for the crystal form, illustrating that the stability of the crystal is closely associated with the intermolecular interactions involving the conformer in the asymmetric unit of the crystal.
Homo‐ and Cross Coupling of C‐2 Propargyl Substituted Triterpenoic Acids: Synthesis of Novel Symmetrical and Unsymmetrical Triterpene 1,3‐Diynes
Authors: Gubaidullin Rinat R. , Khalitova Rezeda R. , Nedopekina Darya A. , Spivak Anna Yu.
Published: December 2018

A synthesis of the first representatives of symmetrical and unsymmetrical triterpene 1,3‐diynes in which one or two triterpene cores are linked by a diyne spacer at the C‐2 position of ring A is described. The new triterpenoids are prepared by Cu‐ and Pd‐catalyzed acetylenic homo‐ and cross coupling of accessible C‐2 propynyl derivatives of betulinic, ursolic, and oleanolic acids.
Ligand Influence on Structural Properties and Reactivity of Bis(μ‐oxo)dimanganese(III,IV) Species and Comparison of Reactivity with Terminal MnIV‐oxo Complexes
Authors: Lee Yuri , Jackson Timothy A.
Published: December 2018

The ligand influence on structure and reactivity of a pair of bis(μ‐oxo)dimanganese(III,IV) complexes was investigated. The pentadentate N4py and DMMN4py ligands were employed to assemble the [MnIIIMnIV(μ‐O)2(N4py)2]3+ (1) and [MnIIIMnIV(μ‐O)2(DMMN4py)2]3+ (2) species by H2O2 oxidation of the corresponding MnII complexes. The electronic absorption and EPR properties of 1 and 2 are nearly identical. Analysis of the EXAFS region of the Mn K‐edge XAS spectra of 1 and 2 reveals comparable Mn‐ligand and Mn−Mn distances. Molecular structures of 1 and 2 from DFT calculations showed only minor variations in Mn‐ligand bond lengths between these complexes. Despite these structural similarities, a ligand influence was observed on the MnIIIMnIV to MnIIIMnIII reduction potential. Nonetheless, the oxidation of 2,4‐di‐tert‐butylphenol by 1 and 2 proceeded at essentially identical rates. In contrast, reactivity comparison between 2 and the corresponding monomeric MnIV‐oxo species, [MnIV(O)(DMMN4py)]2+, showed that the latter complex is a vastly superior oxidant for O−H bond oxidation, showing a rate enhancement of 105 at parity of substrate and temperature.
Rhodium‐Catalyzed Mild C7‐Amination of Indolines with Nitrosobenzenes
Authors: Xiong Dan , Wang Lianhui , Jie Lianghua , Yang Zi , Li Lulin , Cui Xiuling
Published: December 2018

A mild and practical Rh(III)‐catalyzed C7–H amination of indolines has been described, which allows the synthesis of a variety of 7‐amino‐substituted indolines with good functional group tolerance and high atom economy. Notably, nitrosobenzenes serve as nitrogen source in this transformation, and therefore behave environmentally friendly for C−N bond constructions.
When and how to shift gears: Dynamic trade‐offs among adjustment, opportunity, and transaction costs in response to an innovation shock
Authors: Bigelow Lyda , Nickerson Jackson A. , Park Woo‐Yong
Published: December 2018

Research Summary

This study explores incumbent responses to the architectural innovation shock of index shifting in the bicycle component industry. Incumbents differed by when they imitated and by organization of production—some integrated while others outsourced components—and many of these decisions changed over time, which are not explained by extant theory. This paper develops a theory that predicts timing of imitation and organizational choice for component manufacturing that highlights a dynamic trade‐off among adjustment, opportunity, and transaction costs that explains timing of imitation, organizational structure of component manufacturing, and changes in organizational structure. Empirical analysis finds support for a fundamental trade‐off among these costs in response to an innovation shock.

Managerial Summary

An innovation shock presents managers both an opportunity to reposition and gain advantage against competitors and creates competitive pressure to do so. When and how should firms respond to such shocks? This paper develops a comparative approach to help managers decide when and how to imitate an innovation shock. The paper recommends comparatively assessing adjustment costs, opportunity costs of moving late, and initially outsourcing to imitate quickly even though doing so may be costly and problematic over the long‐run. The paper also predicts when firms should integrate to produce more efficiently. These findings are illustrated through the introduction and adoption of index shifting in the sport bicycling market from 1980 through 1995.
On the edge of degradation: Autophagy regulation by RNA decay
Authors: Delorme‐Axford Elizabeth , Klionsky Daniel J.
Published: December 2018

Cells must dynamically adapt to altered environmental conditions, particularly during times of stress, to ensure their ability to function effectively and survive. The macroautophagy/autophagy pathway is highly conserved across eukaryotic cells and promotes cell survival during stressful conditions. In general, basal autophagy occurs at a low level to sustain cellular homeostasis and metabolism. However, autophagy is robustly upregulated in response to nutrient deprivation, pathogen infection and increased accumulation of potentially toxic protein aggregates and superfluous organelles. Within the cell, RNA decay maintains quality control to remove aberrant transcripts and regulate appropriate levels of gene expression. Recent evidence has identified components of the cellular mRNA decay machinery as novel regulators of autophagy. Here, we review current findings that demonstrate how autophagy is modulated through RNA decay.

This article is categorized under:

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms

RNA Turnover and Surveillance > Regulation of RNA Stability
Tr(F3) supersymmetric form factors and maximal transcendentality. Part I. $$ \mathcal{N} $$ = 4 super Yang-Mills
Authors: Brandhuber Andreas , Kostacińska Martyna , Penante Brenda , Travaglini Gabriele
Published: December 2018

Abstract

In the large top-mass limit, Higgs plus multi-gluon amplitudes in QCD can be computed using an effective field theory. This approach turns the computation of such amplitudes into that of form factors of operators of increasing classical dimension. In this paper we focus on the first finite top-mass correction, arising from the operator Tr(F
3), up to two loops and three gluons. Setting up the calculation in the maximally supersymmetric theory requires identification of an appropriate supersymmetric completion of Tr(F
3), which we recognise as a descendant of the Konishi operator. We provide detailed computations for both this operator and the component operator Tr(F
3), preparing the ground for the calculation in

$$ \mathcal{N} $$

N

< 4, to be detailed in a companion paper. Our results for both operators are expressed in terms of a few universal functions of transcendental degree four and below, some of which have appeared in other contexts, hinting at universality of such quantities. An important feature of the result is a delicate cancellation of unphysical poles appearing in soft/collinear limits of the remainders which links terms of different transcendentality. Our calculation provides another example of the principle of maximal transcendentality for observables with non-trivial kinematic dependence.
Tr(F3) supersymmetric form factors and maximal transcendentality. Part II. 0 <$$ \mathcal{N} $$< 4 super Yang-Mills
Authors: Brandhuber Andreas , Kostacińska Martyna , Penante Brenda , Travaglini Gabriele
Published: December 2018

Abstract

The study of form factors has many phenomenologically interesting applications, one of which is Higgs plus gluon amplitudes in QCD. Through effective field theory techniques these are related to form factors of various operators of increasing classical dimension. In this paper we extend our analysis of the first finite top-mass correction, arising from the operator Tr(F
3), from

$$ \mathcal{N} $$

N

= 4 super Yang-Mills to theories with

$$ \mathcal{N} $$

N

< 4, for the case of three gluons and up to two loops. We confirm our earlier result that the maximally transcendental part of the associated Catani remainder is universal and equal to that of the form factor of a protected trilinear operator in the maximally supersymmetric theory. The terms with lower transcendentality deviate from the

$$ \mathcal{N} $$

N

= 4 answer by a surprisingly small set of terms involving for example ζ
2, ζ
3 and simple powers of logarithms, for which we provide explicit expressions.
On the entanglement entropy of Maxwell theory: a condensed matter perspective
Authors: Pretko Michael
Published: December 2018

Abstract

Despite the seeming simplicity of the theory, calculating (and even defining) entanglement entropy for the Maxwell theory of a U(1) gauge field in (3+1) dimensions has been the subject of controversy. It is generally accepted that the ground state entanglement entropy for a region of linear size L behaves as an area law with a subleading logarithm, S = αL
2 − γ log L. While the logarithmic coefficient γ is believed to be universal, there has been disagreement about its precise value. After carefully accounting for subtle boundary corrections, multiple analyses in the high energy literature have converged on an answer related to the conformal trace anomaly, which is only sensitive to the local curvature of the partition. In contrast, a condensed matter treatment of the problem yielded a topological contribution which is not captured by the conformal field theory calculation. In this perspective piece, we review aspects of the various calculations and discuss the resolution of the discrepancy, emphasizing the important role played by charged states (the “extended Hilbert space”) in defining entanglement for a gauge theory. While the trace anomaly result is sufficient for a strictly pure gauge field, coupling the gauge field to dynamical charges of mass m gives a topological contribution to γ which survives even in the m → ∞ limit. For many situations, the topological contribution from dynamical charges is physically meaningful and should be taken into account. We also comment on other common issues of entanglement in gauge theories, such as entanglement distillation, algebraic definitions of entanglement, and gauge-fixing procedures.
The Hybrid Electronic Medical Registry Allows Benchmarking of Quality of Trauma Care: A Five‐Year Temporal Overview of the Trauma Burden at a Major Trauma Centre in South Africa
Authors: Donovan M. M. , Kong V. Y. , Bruce J. L. , Laing G. L. , Bekker W. , Manchev V. , Smith M. , Clarke D. L.
Published: December 2018

Introduction

This study is a five‐year follow‐up of previously published review of the trauma workload at our institution. It aims to provide evidence about the quality of trauma care delivered by a major academic trauma service in South Africa to provide a temporal analysis of trauma trends in the city of Pietermaritzburg.

Materials and methods

All trauma patients admitted by the Pietermaritzburg Metropolitan Trauma Service (PMTS) for the period December 2012‐April 2018 were retrieved from the Hybrid Electronic Medical Registry (HEMR) for analysis.

Results

Over the five‐year period, a total of 8722 trauma patients were admitted to Grey’s Hospital. There were 7242 (83.0%) males. The average age was 29.66 years. A total of 1719 (19.7%) patients less than 19 years of age, 377 (4.3%) older than 60 years of age and 1480 (17.0%) female patients were admitted following trauma. Table 3 breaks down the mechanism of trauma. A total of 5027 patients sustained blunt trauma (57.6%), and 3334 (38.5%) sustained penetrating trauma. A total of 4808 patients sustained intentional trauma implying that 55.1% of all trauma was secondary to grievous bodily harm or assault either in the form of a stab wound or GSW or of an assault. There was a total of 2232 road traffic‐related incidents, of which 37.9% (845) were pedestrian victims. The mortality rate for all trauma admissions was 4.5% (396). Of these 396 deaths, 64 (16.2%) were classified at the morbidity and mortality conference as being avoidable.

Conclusions

The HEMR has allowed us to track the burden of trauma presenting to our institution over a five‐year period. This confirms previous studies over shorter time periods from our institution. The pattern of trauma has remained consistent, and the previously described high levels show no sign of decreasing. Interventions to try and reduce this burden are urgently required.
Understanding Disparities in Surgical Outcomes for Medicaid Beneficiaries
Authors: Claflin Jake , Dimick Justin B. , Campbell Darrell A. , Englesbe Michael J. , Sheetz Kyle H.
Published: December 2018

Background

Few studies have evaluated whether outcome disparities between Medicaid and private insurance beneficiaries are driven by the hospital at which the patient receives care. The purpose of this study was to evaluate the effect of the hospital on surgical outcomes in Medicaid beneficiaries.

Methods

We identified 139,566 non‐elderly Medicaid and private insurance beneficiaries undergoing general, vascular, or gynecological surgery between 2012 and 2017 using a statewide clinical registry in Michigan. We calculated risk‐adjusted rates of complications, readmissions, emergency department (ED) visits, and post‐acute care utilization using multivariable logistic regression, accounting for patient and procedural factors. We then evaluated whether, and to what extent, the hospital influenced outcome disparities between Medicaid and privately insured beneficiaries.

Results

Risk‐adjusted rates for all outcomes were higher in Medicaid beneficiaries. For example, overall post‐discharge ED visit rates were 14.3% (95% CI 13.7% to 14.9%) for Medicaid compared to 7.5% (95% CI 7.1% to 7.9%, P < 0.01) for private insurance beneficiaries. Hospital factors explained 3.9% of the observed difference in complication rates between Medicaid and private insurance beneficiaries. In contrast, hospital factors explained a greater proportion of the disparities in readmissions (30.6%), ED visits (33.0%), and post‐acute care utilization (16.1%). Results were similar when restricting the study population to elective cases only.

Conclusions

Hospital factors account for a significant proportion of the disparities in post‐discharge resource utilization between Medicaid and private insurance beneficiaries. Policies aiming to improve the quality and equity of surgical care for Medicaid beneficiaries should focus on the post‐discharge period.
Non-eliminative Structuralism, Fregean Abstraction, and Non-rigid Structures
Authors: Wigglesworth John
Published: December 2018

Linnebo and Pettigrew (Philos Q 64:267–283, 2014) have recently developed a version of non-eliminative mathematical structuralism based on Fregean abstraction principles. They recognize that this version of structuralism is vulnerable to the well-known problem of non-rigid structures. This paper offers a solution to the problem for this version of structuralism. The solution involves expanding the languages used to describe mathematical structures. We then argue that this solution is philosophically acceptable to those who endorse mathematical structuralism based on Fregean abstraction principles.
Modeling Microstructure Evolution in a Martensitic Stainless Steel Subjected to Hot Working Using a Physically Based Model
Authors: Safara Nima , Engberg Göran , Ågren John
Published: December 2018

The microstructure evolution of a martensitic Stainless steel subjected to hot compression is simulated with a physically based model. The model is based on coupled sets of evolution equations for dislocations, vacancies, recrystallization, and grain growth. The advantage of this model is that with only a few experiments, the material-dependent parameters of the model can be calibrated and used for a new alloy in any deformation condition. The experimental data of this work are obtained from a series of hot compression, and subsequent stress relaxation tests performed in a Gleeble thermo-mechanical simulator. These tests are carried out at various temperatures ranging from 900 to 1200 °C, strains up to 0.7, and strain rates of 0.01, 1, and 10 s−1. The grain growth, flow stress, and stress relaxations are simulated by finding reasonable values for model parameters. The flow stress data obtained at the strain rate of 10 s−1 were used to calibrate the model parameters and the predictions of the model for the lower strain rates were quite satisfactory. An assumption in the model is that the structure of second phase particles does not change during the short time of deformation. The results show a satisfactory agreement between the experimental data and simulated flow stress, as well as less than 5 pct difference for grain growth simulations and predicting the dominant softening mechanisms during stress relaxation according to the strain rates and temperatures under deformation.
Machine Learning–Based Reduce Order Crystal Plasticity Modeling for ICME Applications
Authors: Yuan Mengfei , Paradiso Sean , Meredig Bryce , Niezgoda Stephen R.
Published: December 2018

Crystal plasticity simulation is a widely used technique for studying the deformation processing of polycrystalline materials. However, inclusion of crystal plasticity simulation into design paradigms such as integrated computational materials engineering (ICME) is hindered by the computational cost of large-scale simulations. In this work, we present a machine learning (ML) framework using the material information platform, Open Citrination, to develop and calibrate a reduced order crystal plasticity model for face-centered cubic (FCC) polycrystalline materials, which can be both rapidly exercised and easily inverted. The reduced order model takes crystallographic texture, constitutive model parameters, and loading condition as inputs and returns the stress-strain curve and final texture. The model can also be inverted and take a stress-strain curve, loading condition, and final texture as inputs and return the initial texture and constitutive model parameters as outputs. Principal component analysis (PCA) is used to develop an efficient description of the crystallographic texture. A viscoplastic self-consistent (VPSC) crystal plasticity solver is used to create the training data by modeling the stress-strain behavior and evolution of texture during deformation processing.
Septic arthritis
Authors: Abbod Hatem , Al-Otaibi Lefian , Alshamiri Kamal
Published: December 2018

Septic arthritis is truly an emergency condition that needs an early diagnosis by appropriate clinical examination/judgment and using fast, available, and accurate radiological imaging and laboratory septic workup. Early diagnosis may prevent complications that may otherwise lead to the patient's disability.
The Age‐Well observational study on expert meditators in the Medit‐Ageing European project
Authors: Lutz Antoine , Klimecki Olga M. , Collette Fabienne , Poisnel Géraldine , Arenaza‐Urquijo Eider , Marchant Natalie L. , De La Sayette Vincent , Rauchs Géraldine , Salmon Eric , Vuilleumier Patrick , Frison Eric , Vivien Denis , Chételat Gaël ,   Medit‐Ageing Research Group
Published: December 2018

Introduction

The Age‐Well observational, cross‐sectional study investigates the affective and cognitive mechanisms of meditation expertise with behavioral, neuroimaging, sleep, and biological measures sensitive to aging and Alzheimer's disease (AD).

Methods

Thirty cognitively unimpaired individuals aged 65 years or older with at least 10,000 hours of practice in mindfulness meditation (MM) and loving‐kindness and compassion meditation (LKCM) are selected. The outcomes are the neuroimaging brain correlates of MM and LKCM and the assessments of long‐term meditation practices on behavioral, neural, and biological measures as compared to nonmeditator older controls from the Age‐Well randomized controlled trial.

Results

Recruitment and data collection began in late 2016 and will be completed by late 2019.

Discussion

Results are expected to foster the understanding of the effects of meditation expertise on aging and of the mechanisms of action underlying the meditation intervention in the Age‐Well randomized controlled trial. These finding will contribute to the design of meditation‐based prevention randomized controlled trials for the aged population and to the exploration of the possible long‐time developmental trajectory of meditation training.
Mixing and reaction in turbulent plumes: the limits of slow and instantaneous chemical kinetics
Authors: Mingotti N. , Cardoso S. S. S.
Published: December 2018

We investigate the behaviour of a reactive plume in the two limiting cases of slow and instantaneous chemical reactions. New laboratory measurements show that, whereas the slow reaction between the source and entrained chemical species takes place within the whole volume of each eddy in the plume, the fast reaction develops preferentially at the periphery of the eddies. We develop a new model that quantifies the mixing of the reactive buoyant fluids at the Batchelor scale and thereby the progress of the fast reaction. We present a series of new experimental results that suggest that a critical distance from the source, $z_{crit}$, exists at which the volume of fluid that is entrained from the ambient is equal to that which is mixed within the plume at the Batchelor scale. For $z>z_{crit}$, only a fraction of the entrained fluid is rapidly mixed and reacts with the plume fluid. The results of the new experiments enable us to quantify the distance from the source at which an instantaneous reaction reaches completion, and show that it can be significantly larger than the distance $L_{s}$ at which the stoichiometric dilution of the plume fluid is achieved. In the limit of an instantaneous reaction, the longitudinal profiles of source chemical concentration in the plume depend on $(z_{crit}/L_{s})^{5/6}$. The predictions of the model are validated against the experimental results, and the profiles of source chemical concentration in the plume for slow and fast reactions are compared.