bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Oxidation of Hf–Nb Alloys as a Valuable Route to Prepare Mixed Oxides of Tailored Dielectric Properties
Authors: Zaffora Andrea , Di Quarto Francesco , Kura Chiharu , Sato Yuki , Aoki Yoshitaka , Habazaki Hiroki , Santamaria Monica
Published: April 2018

Metal oxides with high dielectric constant are extensively studied in the frame of substituting SiO2 as gate dielectric in nanoelectronic devices. Here, high‐k mixed HfO2/Nb2O5 oxides are prepared by a facile electrochemical route starting from sputtering‐deposited Hf–Nb alloys with several compositions. Transmission electron microscopy, grazing incidence X‐ray diffraction, and glow discharge optical emission spectroscopy are employed to study the oxide structures, disclosing a crystalline–amorphous transition of the electrochemically prepared oxides by increasing the Nb content. Photo‐electrochemical measurements allow the observation of optical transitions ascribed to localized states inside oxide bandgap induced by the presence of oxygen vacancies for Hf‐rich oxides. Impedance measurements, coupled with withstand voltage and leakage current estimates, provide a comprehensive view of the real dielectric properties of the oxides. The highest ε is estimated for the anodic oxide grown on Hf–39 at% Nb (i.e., 45) but thin film grown on Hf–57 at% Nb alloy shows the best dielectric properties, revealing high dielectric constant, high withstand voltage, and low leakage current. Promising equivalent oxide thickness (down to 0.38 nm) is estimated for the oxide thin layers. The electrochemical oxidation represents a valuable and reliable way to prepare high‐k thin oxide films with tailored and controlled dielectric properties.
Photocurrent, Photovoltage, and Rectification in Large‐Area Bilayer Molecular Electronic Junctions
Authors: Smith Scott R. , McCreery Richard L.
Published: April 2018

Bilayer donor–acceptor molecular junctions are successfully fabricated with active layer thickness <15 nm to study the mechanism of photo‐induced charge transport. The bilayer devices exhibit lifetimes greater than 1 h with laser irradiation, and a strong dependence of the sign and magnitude of the photovoltage and photocurrent on structure and order of the molecular layers. A distinct feature of the bilayer structure is covalent bonding between the donor and acceptor molecular layers, which permits simultaneous absorption and charge separation across a covalent heterojunction. In addition to providing probes of internal energy levels and charge transport in molecular junctions, photo‐induced currents and voltages may potentially be useful in light‐weight, durable, and flexible photodetectors.
The Effect of Hydrophobicity of Ammonium Salts on Stability of Quasi‐2D Perovskite Materials in Moist Condition
Authors: Zheng Haiying , Liu Guozhen , Zhu Liangzheng , Ye Jiajiu , Zhang Xuhui , Alsaedi Ahmed , Hayat Tasawar , Pan Xu , Dai Songyuan
Published: April 2018

With the potential of achieving high efficiency and low production costs, perovskite solar cells (PSCs) have attracted great attention. However, their unstableness under moist condition has retarded the commercial development. Recently, 2D perovskites have received a lot of attention due to their high moisture resistance. In this work, four quasi 2D quasi perovskites are prepared, then their stability under moist condition is investigated. The surface morphology, crystal structure, optical properties, and photovoltaic performance are measured. Among the four quasi‐2D perovskites, (C6H5CH2NH3)2(FA)8Pb9I28 has the best performance: uniform and dense film, extremely well‐oriented crystal structure, strong absorption, and a high power conversion efficiency (PCE) of 17.40%. The aging tests show that quasi‐2D perovskites are more stable under moist conditions than FAPbI3 is. The (C6H5CH2NH3)2(FA)8Pb9I28 quasi‐2D perovskite devices exhibit high humidity stability, maintaining 80% of the starting PCE after 500 h under 80% relative humidity. Compared with other quasi‐2D perovskites, (C6H5CH2NH3)2(FA)8Pb9I28 has the highest humidity stability, due to their strongest hydrophobicity from C6H5CH2NH3+. This work demonstrates that the properties of perovskite materials can be modified by adding different ammonium salts into FAPbI3. Thus, by introducing ammonium salts with high hydrophobic properties the fabrication of highly efficient and stable 2D PSCs may be possible.
On the Balance of Intercalation and Conversion Reactions in Battery Cathodes
Authors: Hannah Daniel C. , Sai Gautam Gopalakrishnan , Canepa Pieremanuele , Ceder Gerbrand
Published: April 2018

A thermodynamic analysis of the driving forces is presented for intercalation and conversion reactions in battery cathodes across a range of possible working ion, transition metal, and anion chemistries. Using this body of results, the importance of polymorph selection as well as chemical composition on the ability of a host cathode to support intercalation reactions is analyzed. It is found that the accessibility of high energy charged polymorphs in oxides generally leads to larger intercalation voltages favoring intercalation reactions, whereas sulfides and selenides tend to favor conversion reactions. Furthermore, it is observed that Cr‐containing cathodes favor intercalation more strongly than those with other transition metals. Finally, it is concluded that two‐electron reduction of transition metals (as is possible with the intercalation of a 2 + ion) will favor conversion reactions in the compositions studied.
Ethane‐selective carbon composites CPDA@A‐ACs with high uptake and its enhanced ethane/ethylene adsorption selectivity
Authors: Liang Wanwen , Wu Ying , Xiao Huiyu , Xiao Jing , Li Yingwei , Li Zhong
Published: April 2018

Novel composites (CPDA@A‐ACs) of carbonized polydopamine (CPDA) and asphalt‐based activated carbons (A‐ACs) were successfully synthesized, and characterized for adsorption separation of ethane/ethylene. The resulting CPDA@A‐ACs exhibited high Brunauer–Emmett–Teller surface area of 1971 m2/g. The O and N contents on CPDA@A‐ACs are higher than those on A‐ACs due to the introduction of CPDA. Interestingly, CPDA@A‐ACs exhibited great preferential adsorption of ethane over ethylene. Its ethane capacity reached as high as 7.12 mmol/g at 100 kPa and 25°C, and its ethane/ethylene adsorption selectivity became higher compared to A‐ACs, reaching as high as 3.0∼20.6 below 100 kPa, significantly superior to the reported ethane‐selective adsorbents. Simulation results revealed the mechanism of enhanced selectivity toward C2H6/C2H4, and suggested that the surface oxygen functionalities of the composites play predominant role in enhancing ethane/ethylene adsorption selectivity. Fixed‐bed experiments showed that C2H6/C2H4 mixtures can be well separated at room temperature, suggesting great potential for industrial C2H6/C2H4 separation. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3390–3399, 2018
Reproductive health, obesity, and cardiometabolic risk factors among Samoan women
Authors: Maredia H. , Hawley N. L. , Lambert‐Messerlian G. , Fidow U. , Reupena M. S. , Naseri T. , McGarvey S. T.
Published: April 2018

Objectives

Obesity leads to deleterious effects on not only cardiovascular health but also on the reproductive health of women. We estimate the prevalence of menstrual irregularity and of polycystic ovarian syndrome (PCOS) in Samoan women, among whom obesity prevalence is extremely high. We explore the association of these reproductive health conditions with adiposity, cardiometabolic risk factors, and androgen levels.

Methods

A cross‐sectional sample of Samoan women 25–39 years of age (n = 470) from a larger population‐based genome‐wide association study of adiposity and cardiometabolic disease was assessed for the prevalence of oligomenorrhea/amenorrhea (OM/AM) using a self‐reported questionnaire. Serum androgens and anti‐Müllerian hormone levels were assayed to determine hyperandrogenemia and presence of polycystic ovaries (PCO), respectively, using criterion values. PCOS was classified using NIH guidelines of having at least two of the three conditions: menstrual irregularity, hyperandrogenism, and PCO. We contrasted socio‐demographic, reproductive health, and cardiometabolic risk factors between those with and without OM/AM and similarly for PCOS.

Results

The prevalence of OM/AM was 7.4% (95% CI: 5.1, 9.8), and women with OM/AM had significantly higher central adiposity. PCOS was estimated at 6.8% (95% CI: 4.5, 9.1), and those with PCOS were younger but had higher overall and central adiposity measures, higher triglycerides, and higher prevalence of insulin resistance than women without PCOS.

Conclusions

The prevalence of menstrual irregularity and PCOS are less than hypothesized given the high levels of adiposity in this population. Nevertheless, Samoan women with menstrual irregularity and other features of PCOS have significantly poorer metabolic health.
Congenital heart diseases and cardiovascular abnormalities in 22q11.2 deletion syndrome: From well‐established knowledge to new frontiers
Authors: Unolt Marta , Versacci Paolo , Anaclerio Silvia , Lambiase Caterina , Calcagni Giulio , Trezzi Matteo , Carotti Adriano , Crowley Terrence Blaine , Zackai Elaine H. , Goldmuntz Elizabeth , Gaynor James William , Digilio Maria Cristina , McDonald‐McGinn Donna M. , Marino Bruno
Published: April 2018

Congenital heart diseases (CHDs) and cardiovascular abnormalities are one of the pillars of clinical diagnosis of 22q11.2 deletion syndrome (22q11.2DS) and still represent the main cause of mortality in the affected children. In the past 30 years, much progress has been made in describing the anatomical patterns of CHD, in improving their diagnosis, medical treatment, and surgical procedures for these conditions, as well as in understanding the underlying genetic and developmental mechanisms. However, further studies are still needed to better determine the true prevalence of CHDs in 22q11.2DS, including data from prenatal studies and on the adult population, to further clarify the genetic mechanisms behind the high variability of phenotypic expression of 22q11.2DS, and to fully understand the mechanism responsible for the increased postoperative morbidity and for the premature death of these patients. Moreover, the increased life expectancy of persons with 22q11.2DS allowed the expansion of the adult population that poses new challenges for clinicians such as acquired cardiovascular problems and complexity related to multisystemic comorbidity. In this review, we provide a comprehensive review of the existing literature about 22q11.2DS in order to summarize the knowledge gained in the past years of clinical experience and research, as well as to identify the remaining gaps in comprehension of this syndrome and the possible future research directions.
Soft tissue nasal asymmetry as an indicator of orofacial cleft predisposition
Authors: Zhang Charles , Miller Steven F. , Roosenboom Jasmien , Wehby George L. , Moreno Uribe Lina M. , Hecht Jacqueline T. , Deleyiannis Frederic W. B. , Christensen Kaare , Marazita Mary L. , Weinberg Seth M.
Published: April 2018

The biological relatives of offspring with nonsyndromic orofacial clefts have been shown to exhibit distinctive facial features, including excess asymmetry, which are hypothesized to indicate the presence of genetic risk factors. The significance of excess soft tissue nasal asymmetry in at‐risk relatives is unclear and was examined in the present study. Our sample included 164 unaffected parents from families with a history of orofacial clefting and 243 adult controls. Geometric morphometric methods were used to analyze the coordinates of 15 nasal landmarks collected from three‐dimensional facial surface images. Following generalized Procrustes analysis, Procrustes ANOVA and MANOVA tests were applied to determine the type and magnitude of nasal asymmetry present in each group. Group differences in mean nasal asymmetry were also assessed via permutation testing. We found that nasal asymmetry in both parents and controls was directional in nature, although the magnitude of the asymmetry was greater in parents. This was confirmed with permutation testing, where the mean nasal asymmetry was significantly different (p < .0001) between parents and controls. The asymmetry was greatest for midline structures and the nostrils. When subsets of parents were subsequently analyzed and compared (parents with bilateral vs. unilateral offspring; parents with left vs. right unilateral offspring), each group showed a similar pattern of asymmetry and could not be distinguished statistically. Thus, the side of the unilateral cleft (right vs. left) in offspring was not associated with the direction of the nasal asymmetry in parents.
Barakat syndrome revisited
Authors: Barakat Amin J. , Raygada Margarita , Rennert Owen M.
Published: April 2018

Barakat syndrome also known as HDR syndrome (Online Mendelian Inheritance in Man [OMIM] 146255), was first described by Barakat et al. in . It is a rare genetic disorder characterized by the triad of hypoparathyroidism “H,” sensorineural deafness “D,” and renal disease “R.” The defect is caused by deletions in chromosome 10p14 or mutations in the GATA3 gene. Although the syndrome has been phenotypically defined by this triad the literature identifies cases with different components with, or without GATA3 defects making the definition of the syndrome confusing. We analyzed 180 cases and attempted to define the phenotype of the syndrome and suggest guidelines for diagnosis. We suggest that the diagnosis could be confirmed in patients who have all three components, and in those who have two components with a positive family history. GATA3 testing is optional to establish the diagnosis in these patients. The syndrome should be considered in patients with isolated “D” where other causes of “D” have been excluded and those with isolated “R,” especially if there is family history of any of these components. In these instances, confirmatory GATA3 testing is indicated to confirm the diagnosis. In patients with nonsurgical “H,” where “D” and “R” have been conclusively ruled out GATA3 studies are not needed as none of these patients were shown to be GATA3 haploinsufficient. Only 64.4% of patients in our review had “HDR.” Some findings might have not been recognized or may could have appeared later in life, but it is evident that this syndrome is genotypically heterogeneous.
Synthesis of Alkyl‐Substituted Pyrazine N‐Oxides by Transition‐Metal‐Free Oxidative Cross‐Coupling Reactions
Authors: Lai Miao , Li Yuan , Wu Zhiyong , Zhao Mingqin , Ji Xiaoming , Liu Pengfei , Zhang Xiaoping
Published: April 2018

Direct access to alkyl‐substituted pyrazine N‐oxides has been accomplished through an intermolecular dehydrogenative cross‐coupling reaction of ethers and pyrazine N‐oxides in the presence of tert‐butyl hydroperoxide (TBHP). This approach successfully provided a variety of alkyl‐substituted pyrazine N‐oxides in up to 96 % yield. Thermogravimetric analysis indicates that the degradation temperature of C2‐alkyated product 3 a is approximately 263 °C. Under pyrolysis conditions, 3 a generated several compounds such as 2,5‐dimethylpyrazine, 2,3,5‐trimethylpyrazine, and 3‐ethyl‐2,5‐dimethylpyrazine, which are characterized by their distinct aromas. The results of the pyrolysis experiment support the use of these compounds as possible flavor additives.
Intra‐specific variation in social organization of Strepsirrhines
Authors: Agnani Paul , Kauffmann Cécile , Hayes Loren D. , Schradin Carsten
Published: April 2018

Strepsirrhines, that is, lemurs, galagos, and lorises, are considered basal primates, making them important to understand the evolution of primate sociality. Apart from some lemurs, they are nocturnal and solitary living, though the view of their sociality nature has changed with field studies being completed. We conducted a review of the primary literature about the social organization (group composition) of strepsirrhines, with the aim to determine whether intra‐specific variation in social organization (IVSO) occurs and to determine how many species are pair‐living, group‐living, or solitary living. We found data in 83 peer‐reviewed studies for 43 of the 132 strepsirrhine species and compared our results using two databases on social systems of mammals published in 2011 and 2013. While it is often assumed that primates show relatively fixed social organizations, we found that 60.5% of species for which data exist have IVSO. We found only 7% of the species to be truly solitary living (with 34.9% additional species to be sometimes solitary living), which is in contrast to the other databases, which had reported 60.9% and 37.7% of species to be solitary. We further explored group compositions by designating “functional groups” (e.g., foraging, breeding, and infant care groups). While functional groups might explain IVSO within a single species, this was not consistent over species with IVSO, such that IVSO was poorly explained by functional groups. Our study supports the view that most strepsirrhines are social (58.1% of species with another 34.9% of species sometimes living in pairs or groups) and show complex and often variable social organizations; reinforcing the assumption that the ancestor of all primates was social and not solitary.
Schistosomiasis and hydration status: Schistosoma haematobium, but not Schistosoma mansoni increases urine specific gravity among rural Tanzanian women
Authors: Rosinger Asher Y. , Young Sera L. , Collins Shalean M. , Haider Syeda Razia , Mishra Pallavi , Nagai Honest T. , Petro Mnyeshi , Downs Jennifer A.
Published: April 2018

Objectives

Schistosome infections can damage organs important for water homeostasis, especially the kidneys. Urogenital schistosomiasis (caused by Schistosoma haematobium) increases protein and blood in urine and intestinal schistosomiasis (caused by S. mansoni) affects total body water. However, no data exist on how different schistosome species affect urine specific gravity (USG), a hydration biomarker. Therefore, we assessed the relationship between S. haematobium‐ and S. mansoni‐infected and uninfected women and USG in rural Tanzania.

Materials and methods

Surveys were conducted and stool and urine samples were collected among 211 nonpregnant women aged 18–50. S. haematobium eggs were detected using the urine filtration method. S. mansoni eggs were detected using the Kato Katz method. USG was measured using a refractometer and analyzed as both a continuous and dichotomous variable. Regression (linear/logistic) models were estimated to test the relationship between infection and hydration status.

Results

The prevalence of S. haematobium was 5.9% and S. mansoni was 5.4% with no coinfections. In regression models, S. haematobium‐infected women had significantly higher USG (Beta = 0.007 g mL−1; standard error = 0.002; p = 0.001) and odds (Odds ratio: 7.76, 95% CI: 1.21‐49.5) of elevated USG (>1.020 g mL−1) than uninfected women, whereas S. mansoni‐infected women did not.

Discussion

Schistosoma haematobium, but not S. mansoni, infection is associated with higher USG and risk of inadequate hydration. Future work should determine whether findings are attributable to parasite‐induced debris in urine or urinary tract pathologies and signs of renal damage. Human and non‐human primate studies using USG in schistosome‐endemic areas should account for schistosomiasis.
The inside tract: The appendicular, cecal, and colonic microbiome of captive aye‐ayes
Authors: Greene Lydia K. , McKenney Erin A.
Published: April 2018

Objectives

The aye‐aye (Daubentonia madagascariensis) is famous for its feeding strategies that target structurally defended, but high‐quality resources. Nonetheless, the influence of this digestible diet on gut microbial contributions to aye‐aye metabolism and nutrition remains unexplored. When four captive aye‐ayes were unexpectedly lost to persin toxicity, we opportunistically collected samples along the animals' gastrointestinal tracts. Here we describe the diversity and composition of appendicular, cecal, and colonic consortia relative to the aye‐aye's unusual feeding ecology.

Materials and methods

During necropsies, we collected digestive content from the appendix, cecum, and distal colon. We determined microbiome structure at these sites via amplicon sequencing of the 16S rRNA gene and an established bioinformatics pipeline.

Results

The aye‐ayes' microbiomes exhibited low richness and diversity compared to the consortia of other lemurs housed at the same facility, and were dominated by a single genus, Prevotella. Appendicular microbiomes were differentiated from more homogenized cecal and colonic consortia by lower richness and diversity, greater evenness, and a distinct taxonomic composition.

Discussion

The simplicity of the aye‐aye's gut microbiome could be attributed to captivity‐induced dysbiosis, or it may reflect this species' extreme foraging investment in a digestible diet that requires little microbial metabolism. Site‐specific appendicular consortia, but more similar cecal and colonic consortia, support the theory that the appendix functions as a safe‐house for beneficial bacteria, and confirm fecal communities as fairly reliable proxies for consortia along the lower gut. We encourage others to make similar use of natural or accidental losses for probing the primate gut microbiome.
Tuning in C‐nociceptors to reveal mechanisms in chronic neuropathic pain
Authors: Jonas Robin , Namer Barbara , Stockinger Lenka , Chisholm Kim , Schnakenberg Mark , Landmann Gunther , Kucharczyk Mateusz , Konrad Christoph , Schmidt Roland , Carr Richard , McMahon Stephen , Schmelz Martin , Rukwied Roman
Published: April 2018

Objective

Develop and validate a low‐intensity sinusoidal electrical stimulation paradigm to preferentially activate C‐fibers in human skin.

Methods

Sinusoidal transcutaneous stimulation (4Hz) was assessed psychophysically in healthy volunteers (n = 14) and neuropathic pain patients (n = 9). Pursuing laser Doppler imaging and single nociceptor recordings in vivo in humans (microneurography) and pigs confirmed the activation of “silent” C‐nociceptors. Synchronized C‐fiber compound action potentials were evoked in isolated human nerve fascicles in vitro. Live cell imaging of L4 dorsal root ganglia in anesthetized mice verified the recruitment of small‐diameter neurons during transcutaneous 4‐Hz stimulation of the hindpaw (0.4mA).

Results

Transcutaneous sinusoidal current (0.05–0.4mA, 4Hz) activated “polymodal” C‐fibers (50% at ∼0.03mA) and “silent” nociceptors (50% at ∼0.04mA), intensities substantially lower than that required with transcutaneous 1‐ms rectangular pulses (“polymodal” ∼3mA, “silent” ∼50mA). The stimulation induced delayed burning (nonpulsating) pain and a pronounced axon‐reflex erythema, both indicative of C‐nociceptor activation. Pain ratings to repetitive stimulation (1 minute, 4Hz) adapted in healthy volunteers by Numeric Rating Scale (NRS) –3 and nonpainful skin sites of neuropathic pain patients by NRS –0.5, whereas pain even increased in painful neuropathic skin by approximately NRS +2.

Interpretation

Sinusoidal electrical stimulation at 4Hz enables preferential activation of C‐nociceptors in pig and human skin that accommodates during ongoing (1‐minute) stimulation. Absence of such accommodation in neuropathic pain patients suggest axonal hyperexcitability that could be predictive of alterations in peripheral nociceptor encoding and offer a potential therapeutic entry point for topical analgesic treatment. Ann Neurol 2018;83:945–957
Serotonin, β‐amyloid, and cognition in Parkinson disease
Authors: Kotagal Vikas , Spino Cathie , Bohnen Nicolaas I. , Koeppe Robert , Albin Roger L.
Published: April 2018

Objective

Serotoninergic neurotransmission may modulate β‐amyloid peptide (Aβ) metabolism through upregulation of α‐secretase. Early Parkinson disease (PD) shows variable serotoninergic denervation, which may impact Aβ deposition.

Methods

We conducted 3 analyses to explore associations between serotoninergic neurotransmission and cerebral Aβ burden in PD. The first was a cross‐sectional imaging study of PD subjects (n = 23) using the serotoninergic transporter positron emission tomography (PET) ligand [11C]3‐amino‐4‐(2‐dimethylaminomethyl‐phenylsulfaryl)‐benzonitrile (DASB) and amyloid PET Pittsburgh compound B ([11C]PiB). The second was a baseline study of Parkinson's Progression Markers Initiative (PPMI) subjects exploring the influence of serotoninergic medications on cerebrospinal fluid (CSF) Aβ‐42 levels (n = 389), controlling for age, sex, Geriatric Depression Scale, disease duration, and education. Third, we fit an interval censored proportional hazard model with longitudinal PPMI data (n = 367) to test whether serotoninergic medication use associates with reduced risk of PD cognitive decline, defined as time to reach a Montreal Cognitive Assessment score ≤ 20, adjusting for baseline caudate dopamine transporter [123I]ioflupane single photon emission computed tomography and CSF Aβ‐42 levels.

Results

Serotoninergic DASB distribution volume ratio (DVR) inversely associated with PiB DVR in the cerebral cortex (Pearson r = −0.478, p = 0.021) but not the striatum (r = −0.264, p = 0.224). In the baseline PPMI analysis, serotoninergic medication use for ≥6 months associated with a lower level of CSF Aβ‐42 (t = −2.20, p = 0.029). In the longitudinal PPMI model, baseline serotoninergic medication use associated with a reduced risk of cognitive decline (t = −2.03, p = 0.043) after controlling for covariates.

Interpretation

Cortical Aβ burden in PD associates inversely with serotoninergic innervation. Serotoninergic medications may alter Aβ metabolism and reduce the risk of PD cognitive decline. Ann Neurol 2018;83:994–1002
Intrathecal immunoglobulin M production: A promising high‐risk marker in clinically isolated syndrome patients
Authors: Huss André , Abdelhak Ahmed , Halbgebauer Steffen , Mayer Benjamin , Senel Makbule , Otto Markus , Tumani Hayrettin
Published: April 2018

Markers predicting the course of patients with clinically isolated syndrome (CIS) toward multiple sclerosis (MS) are urgently needed. We evaluated the predictive values of intrathecal immunoglobulin (Ig) G and IgM production with different methods for conversion to definite MS according to revised McDonald 2010 criteria in a cohort of 126 CIS patients. Intrathecal IgM production showed the highest likelihood ratio for the conversion of CIS patients to definite MS at 6.3, whereas it was 1.4 for oligoclonal IgG bands. We conclude that the determination of intrathecal IgM is a valuable tool to predict the disease course of patients with CIS. Ann Neurol 2018;83:1032–1036
Atrophy and microglial distribution in primary progressive aphasia with transactive response DNA‐binding protein‐43 kDa
Authors: Kim Garam , Bolbolan Kabriya , Gefen Tamar , Weintraub Sandra , Bigio Eileen H. , Rogalski Emily , Mesulam Marek‐Marsel , Geula Changiz
Published: April 2018

Objective

To quantitatively determine the density and distribution of activated microglia across cortical regions and hemispheres in the brains of primary progressive aphasia (PPA) participants with pathological diagnoses of frontotemporal lobar degeneration with transactive response DNA‐binding protein‐43 (TDP‐43) inclusions and to examine the relationships between microglial densities, patterns of focal atrophy, (TDP‐43) inclusions, and clinical phenotype.

Methods

Activated microglia and TDP‐43 inclusions were visualized in whole‐hemisphere brain sections using immunohistochemical methods from five participants with PPA‐TDP. Unbiased stereology was used to bilaterally quantify human leuckocyte antigen/D related–positive activated microglia and TDP‐43 inclusions across five language‐related regions. Density and distribution of both markers were compared across cortical regions and hemispheres, and their relationships to patterns of focal atrophy and clinical phenotype were determined.

Results

Activated microglia displayed asymmetric distribution favoring the language‐dominant hemisphere, consistent with greater postmortem and/or in vivo atrophy in that hemisphere, in PPA‐TDP. In one participant with no asymmetric atrophy, quantitative distribution of microglia also lacked asymmetry. Patterns of microglial activation also showed variation that favored areas of high atrophy in regions affiliated with language function, demonstrating concordance between patterns of microglial activation, atrophy, and clinical phenotype. TDP‐43 also showed higher inclusion densities in areas of high atrophy than in regions with low atrophy, but no clear relationship with microglia density at a regional level.

Interpretation

The initial activation of microglia is most likely a response to cortical abnormalities in PPA‐TDP, which contribute to atrophy. The patterns of microglial activation, TDP‐43 inclusion deposition, atrophy, and clinical phenotype suggest that activated microglia may make unique contributions to cortical thinning and TDP‐43 inclusion formation. Ann Neurol 2018;83:1096–1104
Direct Access to Aryl Bis(trifluoromethyl)carbinols from Aryl Bromides or Fluorosulfates: Palladium‐Catalyzed Carbonylation
Authors: Domino Katrine , Veryser Cedrick , Wahlqvist Benjamin A. , Gaardbo Cecilie , Neumann Karoline T. , Daasbjerg Kim , De Borggraeve Wim M. , Skrydstrup Troels
Published: April 2018

A palladium‐catalyzed carbonylative approach for the direct conversion of (hetero)aryl bromides into their α,α‐bis(trifluoromethyl)carbinols is described, and it employs only stoichiometric amounts of carbon monoxide and trifluoromethyltrimethylsilane. In addition, aryl fluorosulfates proved highly compatible with these reaction conditions. The method is tolerant of a diverse set of functional groups, and it is adaptable to late‐stage carbon‐isotope labeling.
A Very Short Uranium(IV)–Rhodium(I) Bond with Net Double‐Dative Bonding Character
Authors: Lu Erli , Wooles Ashley J. , Gregson Matthew , Cobb Philip J. , Liddle Stephen T.
Published: April 2018

Reaction of [U{C(SiMe3)(PPh2)}(BIPM)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)0.5]2 (BIPM=C(PPh2NSiMe3)2; TMEDA=Me2NCH2CH2NMe2) with [Rh(μ‐Cl)(COD)]2 (COD=cyclooctadiene) affords the heterotrimetallic UIV−RhI2 complex [U(Cl)2{C(PPh2NSiMe3)(PPh[C6H4]NSiMe3)}{Rh(COD)}{Rh(CH(SiMe3)(PPh2)}]. This complex has a very short uranium–rhodium distance, the shortest uranium–rhodium bond on record and the shortest actinide–transition metal bond in terms of formal shortness ratio. Quantum‐chemical calculations reveal a remarkable Rh
UIV net double dative bond interaction, involving RhI 4d
‐ and 4dxy/xz‐type donation into vacant UIV 5f orbitals, resulting in a Wiberg/Nalewajski–Mrozek U−Rh bond order of 1.30/1.44, respectively. Despite being, formally, purely dative, the uranium–rhodium bonding interaction is the most substantial actinide–metal multiple bond yet prepared under conventional experimental conditions, as confirmed by structural, magnetic, and computational analyses.
Exposing the Origins of Irreproducibility in Fluorine NMR Spectroscopy
Authors: Rosenau Carl Philipp , Jelier Benson J. , Gossert Alvar D. , Togni Antonio
Published: April 2018

Fluorine chemistry has taken a pivotal role in chemical reaction discovery, drug development, and chemical biology. NMR spectroscopy, arguably the most important technique for the characterization of fluorinated compounds, is rife with highly inconsistent referencing of fluorine NMR chemical shifts, producing deviations larger than 1 ppm. Herein, we provide unprecedented evidence that both spectrometer design and the current unified scale system underpinning the calibration of heteronuclear NMR spectra have unintentionally led to widespread variation in the standardization of 19F NMR spectral data. We demonstrate that internal referencing provides the most robust, practical, and reproducible method whereby chemical shifts can be consistently measured and confirmed between institutions to less than 30 ppb deviation. Finally, we provide a comprehensive table of appropriately calibrated chemical shifts of reference compounds that will serve to calibrate 19F spectra correctly.
Application of In Situ Techniques for the Characterization of NiFe‐Based Oxygen Evolution Reaction (OER) Electrocatalysts
Authors: Zhu Kaiyue , Zhu Xuefeng , Yang Weishen
Published: April 2018

Developing high‐efficiency and affordable electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a crucial bottleneck on the way to the practical applications of rechargeable energy storage technologies and water splitting for producing clean fuel (H2). In recent years, NiFe‐based materials have proven to be excellent electrocatalysts for OER. Understanding the characteristics that affect OER activity and determining the OER mechanism are of vital importance for the development of OER electrocatalysts. Therefore, in situ characterization techniques performed under OER conditions are urgently needed to monitor the key intermediates together with identifying the OER active centers and phases. In this Minireview, recent advances regarding in situ techniques for the characterization of NiFe‐based electrocatalysts are thoroughly summarized, including Raman spectroscopy, X‐ray absorption spectroscopy, ambient pressure X‐ray photoelectron spectroscopy, Mössbauer spectroscopy, Ultraviolet–visible spectroscopy, differential electrochemical mass spectrometry, and surface interrogation scanning electrochemical microscopy. The results from these in situ measurements not only reveal the structural transformation and the progressive oxidation of the catalytic species under OER conditions, but also disclose the crucial role of Ni and Fe during the OER. Finally, the need for developing new in situ techniques and theoretical investigations is discussed to better understand the OER mechanism and design promising OER electrocatalysts.
Synergy Between DFT Calculations and Experimental Studies on the Optimized Structures and the Antibacterial Potential of Some Novel Tetra‐ and Penta Coordinated Organic‐ Inorganic Hybrid Complexes of Titanium(IV)
Authors: Sharma Shobhana , Kumar Pradeep , Jain Asha , Saxena Sanjiv
Published: April 2018

The generation, structure, reactivity and antibacterial potential of some tetra‐ and penta coordinated organic‐inorganic hybrid complexes of titanium(IV) were comprehensively studied experimentally and theoretically by using density functional theory (DFT). These complexes were generated by the reaction of titanium isopropoxide with sterically demanding oximes of heterocyclic β‐diketones in 1:1 molar ratio in dry benzene. The chemical structures of titanium complexes were systematically modified using relatively sterically undemanding acetoxime as coligand. The reaction of the synthesized complexes TiL(OPri)2 with the relatively undemanding acetoxime in 1:1 molar ratio in dry benzene afforded the complexes of the type TiLL'(OPri). Further reaction of the complexes TiLL'(OPri) with acetoxime in 1:1 molar ratio in dry benzene resulted in the formation of the complexes of the type TiL(L')2. Plausible structures of these newly generated organic‐inorganic hybrid complexes of titanium(IV) were suggested on the basis of physico‐chemical, spectral and mass studies. The optimized structures of the complexes TiLL'(OPri) and TiL(L')2 were given by density functional theory (DFT/B3LYP method). DFT was used to investigate molecular orbitals, molecular electrostatic potential(MEP) and chemical reactivity of the complexes. Some of these complexs were screened against A.Flavus, P. Aeruginosa and E.Coli. These titanium(IV) complexes are potential candidates for use as antibacterial agents. The antibacterial activity of titanium(IV) complexes has been correlated with some of the principal quantum chemical descriptors.
Probing of ferrocenylanilines on model micelle/reverse micelle membrane and their enhanced reactivity for reactive oxidants
Authors: Altaf Ataf A. , Badshah Amin , Lal Bhajan , Murtaza Shahzad , Chatterjee Pabitra B. , Akbar Kamran , Crans Debbie C.
Published: April 2018

Reactive oxygen species are formed in the human body but can be removed by suitable antioxidants. In this study we synthesized and characterized three ferrocene derivatives, 4‐ferrocenylaniline (pFA), 3‐ferrocenylaniline (mFA) and 3‐methyl‐4‐ferrocenylaniline (MeFA), having significant potential to be used as antioxidants. The synthesized compounds are insoluble in water, with the solubility of these compounds increasing in micelle solution. The micelle and reverse micelle solutions were considered as model membranes. The synthesized compounds were probed on the model membranes, made by sodium dioctylsulfosuccinate reverse micelle and tetradecyltrimethylammonium bromide micelle, using 1H NMR spectroscopy. The 1H NMR results indicated that these compounds are present in the polar region of the model membrane interface. Quantitative measurements showed that mFA has the greatest ability to penetrate into the micelle membrane among these compounds, and pFA is least penetrating in this respect. Solubilization of these compounds in aqueous micelle solution facilitates crystallization (of mFA) and enhances the antioxidant potential of these compounds. X‐ray crystal structure analysis revealed that mFA captures water molecules during crystallization in micelle solution. Their ability to act as antioxidants was evaluated, in dimethylsulfoxide (DMSO) and in micelle solution, using standard 1,1‐ diphenyl‐2‐picrylhydrazyl (DPPH) assay. It was found that their antioxidant potential is good in DMSO and that potential increases on the interface of the model membrane. The highest increase (by 19.6%) in the antioxidant potential, on the model membrane interface, was observed for mFA.
Heterogeneous azide–alkyne cycloaddition in the presence of a copper catalyst supported on an ionic liquid polymer/silica hybrid material
Authors: Fehér Klaudia , Nagy Enikő , Szabó Péter , Juzsakova Tatjána , Srankó Dávid , Gömöry Ágnes , Kollár László , Skoda‐Földes Rita
Published: April 2018

Heterogeneous copper catalysts were prepared by the deposition of CuI on a hybrid material consisting of silica and a polymer with imidazolium moieties. The solid materials were characterised using solid‐phase NMR, Fourier transform infrared, Raman and X‐ray photoelectron spectroscopies and Brunauer–Emmett–Teller measurements. The formation of copper–carbene complexes was proved from Raman spectra and the results were supported by density functional theory calculations. The catalyst could be recycled efficiently with low loss of copper. Metal leaching was proved to be facilitated by the use of conditions typical for a homogeneous system (the presence of a polar solvent or the addition of a tertiary amine). Besides simple model reactions, the best catalyst was found to be suitable for the synthesis of triazoles of more elaborate structure, such as ferrocene or steroid derivatives.
F‐doped Ag/AgBr with enhanced visible‐light photocatalytic activity and mechanism
Authors: Bao Ting , Song Limin , Zhang Shujuan
Published: April 2018

Novel F‐doped Ag/AgBr photocatalysts containing various amounts of F− were synthesized by an ion exchange method. The photocatalysts were characterized using X‐ray diffraction (XRD), scanning and transmission electron microscopies, X‐ray photoelectron, ultraviolet–visible absorption and photoluminescence spectroscopies and electron spin resonance (ESR). Powder XRD revealed that F− was inserted into the crystal lattices of AgBr and partially replaced Br−, resulting in the contraction of the AgBr lattices. Methyl orange photodegradation experiments showed that the photocatalytic activity of F‐doped Ag/AgBr was significantly dependent on the amount of F−. Ag/AgBr doped with 0.02 M F− achieved the highest activity of 91% after 8 min. ESR showed the main active species in methyl orange degradation was •OH. The main enhancement mechanism is that F− inhibits the recombination of electron–hole pairs.
Controllable preparation of highly dispersed TiO2 nanoparticles for enhanced catalytic oxidation of dibenzothiophene in fuels
Authors: Lu Qingqing , Peng Wenhui , Xun Suhang , He Minqiang , Ma Ruliang , Jiang Wei , Zhu Wenshuai , Li Huaming
Published: April 2018

The aggregation of nanoparticle catalysts is one of the main problems in catalytic reactions. In this study, a series of TiO2 nanoparticle catalysts with various dispersions were prepared and applied in the catalytic oxidation of dibenzothiophene (DBT) systems. Compositions and structures of the as‐prepared samples were analyzed by means of wide‐angle X‐ray diffraction, Raman and X‐ray photoelectron spectroscopies. The dispersions of TiO2 nanoparticles were controlled by calcining at various temperatures and verified using transmission electron microscopy. It was found that the activities of TiO2 nanoparticles in the catalytic oxidation of DBT were positively correlated with the dispersions. TiO2 nanoparticles calcined at 500 °C (500‐TiO2) showed the best catalytic activity and the oxidation of DBT reached 99.8% under mild conditions. Based on the results of GC–MS analysis, radical trapping experiments and electron spin resonance spectra, •O2− radicals were proved to be the main active species in the oxidation process, and a mechanism is proposed. Meanwhile, the recycling performance of 500‐TiO2 was investigated, and no obvious decrease was observed after six recycles.
Oxido‐peroxido W(VI)‐histidine–MgAl‐layered double hydroxide composite as an efficient catalyst in sulfide oxidation
Authors: Nikkhoo Mohammad , Amini Mojtaba , Morteza S. , Farnia F. , Bayrami Arshad , Bagherzadeh Mojtaba , Gautam Sanjeev , Chae Keun Hwa
Published: April 2018

Oxido‐peroxido W(VI)‐histidine–MgAl‐layered double hydroxide composite was prepared by using MgAl‐layered double hydroxide as a host and oxido‐peroxido W(VI)‐histidine complex as a guest. The composite was characterized by XRD, IR, EDX,SEM and TEM techniques. This composite is tested for catalytic selective sulfoxidation reactions using hydrogen peroxide as oxidant showing good to moderate conversion along with high selectivity.
Highly efficient, catalyst‐free, one‐pot, pseudo five‐component synthesis of novel pyrazoline‐containing Schiff bases, metal complexes formation and computational studies via DFT method
Authors: Hasaninejad Alireza , Mojikhalifeh Sanaz , Beyrati Maryam
Published: April 2018

In this study, a green and high yielding synthesis of novel pyrazoline‐containing Schiff bases via a one‐pot pseudo five‐component condensation reaction under catalyst‐free conditions in EtOH at room temperature is described. Initially, the reaction of 1,1‐bis(methylthio)‐2‐nitroethylene (BMTNE), with NH2NH2.H2O is used for situ preparation of 1,1‐dihydrazino‐2‐nitroethylene (DHNE). Then, wide varieties of aldehydes are added to the mixture to afford the desired products good to excellent yields. This synthetic route is presented with several unique merits such as simplicity in operation and workup, readily presented starting materials, and high functional group tolerance. Additionally, the stoichiometric complex formation of these Schiff bases as ligand (L) with various metal ions [Mn(OAc)2, Cu(OAc)2 and Zn(OAc)2] in general molecular formula [ML] is examined via Job's method. Subsequently, theoretical analysis of the product is accomplished using density functional theory (DFT) calculations. According to the frontier molecular orbital (FMO) analysis, it is found that the aryl group linked to the imine bond contributes as an electron donor in the ligand–metal complex.
Chemometric Characterization of Eight Monovarietal Algerian Virgin Olive Oils
Authors: Guissous Mokhtar , Le Dréau Yveline , Boulkhroune Hasna , Madani Toufik , Artaud Jacques
Published: April 2018

Differences in triacylglycerol, fatty acid, squalene, and tocopherol compositions were demonstrated between 8 varieties of virgin olive oils (Aberkane, Aguenaou, Aharoun, Aimel, Bouchouk Guergour, Bouichret, Chemlal, and Sigoise) from Petite Kabylie area, north eastern Algeria. Fatty acid and triacylglycerol morphotypes characterized each variety. A principal component analysis, based on triacylglycerol, fatty acid, and squalene compositions, differentiates between varieties. Minor fatty acids and squalene, usually not taken into account individually in authentication studies, are strongly involved in this differentiation, whereas the discriminant power of tocopherols is weak. Soft Independent Modeling of Class Analogy classification using chemical compositions as variables showed a high potential to authenticate the varietal origin of Algerian virgin olive oils.
Effects of hydrophilic/hydrophobic surfaces on polymer‐complexation kinetics
Authors: Sayama Daisuke , Hatanaka Masashi , Miyasaka Makoto
Published: April 2018

To establish hydrophilic/hydrophobic effects on polymer‐complexation kinetics, chitosan resins were prepared by radical copolymerization of methacryloyl‐modified chitosans with 2‐hydroxyethyl methacrylate and/or styrene monomers. The primary particles of the gelled copolymers in the suspensions were nicely solidified by basic coagulation bath to form globular beads. Degree of the hydrophilic/hydrophobic properties was controlled by the copolymerization ratio, and each ion‐adsorption kinetics was evaluated by batch method. The initial rate of adsorption in hydrophilic chitosans was higher than that in hydrophobic chitosans, which was attributed to less thickness of the boundary film. We quantitatively evaluated the rate‐determining steps by the initial‐rate analysis, in which the viscosity of the suspension contributes to the film‐diffusion kinetic resistance. The role of hydrophilic/hydrophobic properties of the resins is reasonably rationalized to the length of the boundary films by considering long‐range interactions between the ion and surface. Our results are robust evidence for the ion‐surface interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46493.
Reliable surface modification of dental plastic substrates to reduce biofouling with a photoreactive phospholipid polymer
Authors: Ishihara Kazuhiko , Fukazawa Kyoko , Inoue Yuuki , Koyama Jun , Mori Yoshiyuki , Kinoshita Toru , Hiranuma Katsumi , Yasuda Noboru
Published: April 2018

Plastic substrates have been widely applied in clinical settings for dental treatments. These substrates should be strong enough for long‐term implantation in the oral cavity and should be resistant to biofouling. We developed a new photoreactive phospholipid polymer to reduce biofouling on dental plastics via a photochemical reaction. Poly(methyl methacrylate) (PMMA) and poly(ether ether ketone) (PEEK) were used as dental plastics. To determine the antibiofouling properties on the polymer surface, the phospholipid polymer was covalently immobilized on the substrates by UV irradiation. We evaluated the antibiofouling properties by observing the protein adsorption and cell and bacterial adhesion. Significant protein adsorption and cell adhesion appeared on the bare PMMA and PEEK substrates but decreased dramatically after surface modification with the phospholipid polymer. Thus, this photoreactive polymer shows potential for conferring dental plastics with antibiofouling properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46512.
Analysis of the ‘Dutch Disease’ Effect on the Selected Resource‐Rich ASEAN Economies
Authors: Taguchi Hiroyuki , Khinsamone Soukvisan
Published: April 2018

This article examines the applicability of the Dutch Disease hypothesis by using a vector auto‐regression model, focusing on the resource‐rich and middle‐income economies in the Association of Southeast Asian Nations. The empirical study found that the latecomers of Lao People's Democratic Republic and Myanmar seemed to suffer from the Dutch Disease over the sample period for 1970–2015; and the forerunners of Indonesia and Malaysia, on the other hand, appeared to have no Dutch Disease effect at least in the current period of 1997–2015, although Indonesia had experienced the Dutch Disease in the previous period of 1970–1996. The lessons from the forerunners' experiences in order for the latecomers to escape from the Dutch Disease are to establish some funding system of allocating resource revenues for investment projects; to diversify domestic industries through improving business environments; and to improve institutional quality to reinforce resource governance.