bluuebunny/crossref_metadata_2025 huggingface dataset:
Methylene Bridging Effect on the Structures, Lewis Acidities and Optical Properties of Semi‐planar Triarylboranes
Authors: Doan Thu‐Hong , Chardon Aurélien , Osi Arnaud , Mahaut Damien , Tumanov Nikolay , Wouters Johan , Champagne Benoît , Berionni Guillaume
Published: August 2020

Three synthetic methods towards semi‐planar triarylboranes with two aryl rings connected by a methylene bridge have been developed. The fine‐tuning of their stereoelectronic properties and Lewis acidities was achieved by introducing fluorine, methyl, methoxy, n‐butyl and phenyl groups either at their exocyclic or bridged aryl rings. X‐ray diffraction analysis and quantum‐chemical calculations provided quantitative information on the structural distortion experienced by the near planar hydro‐boraanthracene skeleton during the association with Lewis bases such as NH3 and F−. Though the methylene bridge between the ortho‐positions of two aryl rings of triarylboranes decreased the Gibbs free energies of complexation with small Lewis bases by less than 5 kJ mol−1 relative to the classical Lewis acid BAr3, the steric shielding of the CH2 bridge is sufficient to avoid the formation of Lewis adducts with larger Lewis bases such as triarylphosphines. A newly synthesized spirocyclic amino‐borane with a long intramolecular B−N bond that could be dissociated under thermal process, UV‐irradiation, or acidic conditions might be a potential candidate in Lewis pairs catalysis.
A Streamlined Regenerative Glycosylation Reaction: Direct, Acid‐Free Activation of Thioglycosides
Authors: Escopy Samira , Singh Yashapal , Stine Keith J. , Demchenko Alexei V.
Published: August 2020

Our group has previously reported that 3,3‐difluoroxindole (HOFox) is able to mediate glycosylations via intermediacy of OFox imidates. Thioglycoside precursors were first converted into the corresponding glycosyl bromides that were then converted into the OFox imidates in the presence of Ag2O followed by the activation with catalytic Lewis acid in a regenerative fashion. Reported herein is a direct conversion of thioglycosides via the regenerative approach that bypasses the intermediacy of bromides and eliminates the need for heavy‐metal‐based promoters. The direct regenerative activation of thioglycosides is achieved under neutral reaction conditions using only 1 equiv. NIS and catalytic HOFox without the acidic additives.
From Distinct Metallopeptoids to Self‐Assembled Supramolecular Architectures
Authors: Ghosh Pritam , Fridman Natalia , Maayan Galia
Published: August 2020

The construction of synthetic protein mimics is a central goal in chemistry. A known approach for achieving this goal is the self‐assembly of synthetic biomimetic sequences into supramolecular structures. Obtaining different 3D structures via a simple sequence modification, however, is still challenging. Herein we present the design and synthesis of biomimetic architectures, via the self‐assembly of distinct copper‐peptoid duplexes. We demonstrate that changing only one non‐coordinating side‐chain within the peptoids—sequence‐specific N‐substituted glycine oligomers—leads to different supramolecular structures. Four peptoid trimers incorporating 2,2’‐bipyridine and pyridine ligands, and a non‐coordinating but rather a structure‐directed bulky group were synthesized, and their solutions were treated with Cu2+ in a 1:1 ratio. Single‐crystal X‐ray analysis of the products revealed the self‐assembly of each peptoid into a metallopeptoid duplex, followed by the self‐assembly of multiple duplexes and their packing into a three‐dimensional supramolecular architecture via hydrogen bonding and π–π interactions. Tuning the non‐coordinating side‐chain enables to regulate both the final structure being either a tightly packed helical rod or a nano‐channel, and the pore width of the nano‐channels. Importantly, all the metallopeptoids structures are stable in aqueous solution as verified by cryo‐TEM measurements and supported by UV/Vis and EPR spectroscopies and by ESI‐MS analysis. Thus, we could also demonstrate the selective recognition abilities of the nano‐channels towards glycerol.
Assessment of Industrial Greenhouse Gas Reduction Strategies Within Consistent System Boundaries
Authors: Wich‐Konrad Teresa , Lüke Wiebke , Oles Markus , Deerberg Görge
Published: August 2020

With respect to the climate goals of the greenhouse gas (GHG) neutrality in 2050, different GHG reduction strategies are discussed for industrial processes. For a comparison of the strategies carbon direct avoidance (CDA), carbon capture and storage, and carbon capture and utilization (CCU), the method system expansion is applied. Exemplarily, the CO2 reduction potential and the energy demand are determined. The Carbon2Chem® project is described as an example of CCU for the steel and chemical production. The direct reduction with H2 represents the CDA strategy for the steel industry.
An Overview of the Flame Retardants for Poly(vinyl chloride): Recent States and Perspective†
Authors: Pan Ye‐Tang , Yuan Yongshuai , Wang De‐Yi , Yang Rongjie
Published: August 2020

As a versatile star product, poly(vinyl chloride) (PVC) has kept active in our daily life all through since it was invented. However, the severe fire hazard and heavy smoke produced during combustion, particularly the extensively used flexible PVC products, have been puzzling manufacturers and researchers for ages. Over the last decade, multifarious flame retardants and smoke suppressants were developed for PVC materials. In this review, combined literature with the results based on the research from our group, recent emerged flame retardants and smoke suppressants for PVC are introduced. Meanwhile, the flame retardant mechanisms and experimental analysis results are described to understand the relationship between characters of flame retardants (including chemical compositions, structures or morphologies) and fire performance of the composites. The potential substitutes for traditional harmful flame retardant antimony trioxide are discussed aiming to the emphasis on increasing prominent environmental concerns. In particular, one section is dedicated to new approaches for the preparation of novel environmentally friendly and high‐efficiency flame retardants. It is hoped that this review will not only summarize the new emerged flame retardants and smoke suppressants for PVC, but also provide the new trend to prompt sequent exploration in both academic research and industrial application.
Advances and Prospects of Surface Modification on Nickel‐Rich Materials for Lithium‐Ion Batteries†
Authors: Su Yuefeng , Chen Gang , Chen Lai , Li Qing , Lu Yun , Bao Liying , Li Ning , Chen Shi , Wu Feng
Published: August 2020

Although layered Ni‐rich cathode materials have attracted lots of attention for their high capacity and power density, several significant issues, such as poor thermal stability and moderate cyclability, limit their practical applications. Most of these undesired problems of Ni‐rich materials are caused by the unstable surface or the parasitic reactions at cathode‐electrolyte interface. Surface coating is the most common method to suppress such interfacial problems for Ni‐rich materials. This review focuses on the surface engineering of the Ni‐rich materials in recent years, including the species used in coating, synthetic strategies of uniform coating layer, and the positive effects of coating species on the active materials. Detailed discussions are also taken to describe the formation mechanism of the surface coating layer with design philosophy. Finally, the prospects for further developments and challenges in surface coating are also summarized.
Correlations between cardiac troponin I and nonsustained ventricular tachycardia in hypertrophic obstructive cardiomyopathy
Authors: Liu Limin , Liu Shangyu , Shen Lishui , Tu Bin , Hu Zhicheng , Hu Feng , Zheng Lihui , Ding Ligang , Fan Xiaohan , Yao Yan
Published: August 2020

Background

Nonsustained ventricular tachycardia (NSVT) is an independent risk factor for sudden cardiac death (SCD) in patients with hypertrophic obstructive cardiomyopathy (HOCM). However, data concerning the correlations of cardiac biomarkers and NSVT in HOCM are rather limited.

Hypothesis

Our study aimed to investigate the associations between the occurrence of NSVT and circulating biomarkers representing myocardial injury (cardiac troponin I, cTnI), cardiac function (N‐terminal pro‐brain natriuretic peptide, NT‐pro BNP), and inflammation (high‐sensitivity C‐reactive protein) in a large Chinese HOCM cohort.

Methods

A total of 755 consecutive HOCM patients were recruited. Systematic cardiac evaluations and circulating biomarkers were examined routinely in all subjects under the clinically stable status. According to the results of 24‐hour Holter monitoring, patients were divided into the NSVT group (n = 138) and the nonventricular tachycardia (non‐VT) group (n = 617).

Results

Compared with the non‐VT group, circulating levels of both cTnI and NT‐pro BNP elevated significantly in patients with positive NSVT episodes (P < .001). Multivariable analyses demonstrated that cTnI was independently associated with the presence of NSVT (OR = 1.675, 95% CI: 1.406‐1.994, P < .001). Concentrations of cTnI increased progressively not only with the aggravation of ventricular arrhythmic events (P < .001), but also with the growing risk of SCD in HOCM patients (P < .001). Serum cTnI ≥ 0.0265 ng/mL indicated predictive value for the occurrence of NSVT in the HOCM cohort (area under the curve = 0.707, 95% CI: 0.660‐0.754, P < .001).

Conclusions

Elevated cTnI was an independent determinant of NSVT, and it seemed to be valuable for assessing the clinical status of ventricular arrhythmias and the risk of SCD in patients with HOCM.
Burden of premature ventricular contractions beyond nonsustained ventricular tachycardia is related to the myocardial extracellular space expansion in patients with hypertrophic‐cardiomyopathy
Authors: Chung Hyemoon , Park Chul‐Hwan , Kim Yoonjung , Kim Jong‐Youn , Min Pil‐Ki , Yoon Young Won , Lee Kyung‐A , Lee Byoung Kwon , Hong Bum‐Kee , Kim Tae Hoon , Rim Se‐Joong , Kwon Hyuck Moon , Choi Eui‐Young
Published: August 2020

Background

Although nonsustained ventricular tachycardia (NSVT) is a risk factor for sudden cardiac death in hypertrophic‐cardiomyopathy (HCM), the impact of premature ventricular contraction (PVC) burden, in the absence of NSVT, is not well‐known.

Hypothesis

PVC burden may be associated with myocardial fibrosis and genetic mutations in patients with HCM.

Methods

Of the 212 patients prospectively enrolled to the HCM registry of genetics, 84 were evaluated with both cardiac magnetic resonance, 24‐hour Holter monitoring and genetic analysis. Among them, 71 patients have not been diagnosed with NSVT.

Results

Patients with NSVT (n = 13) had a higher late gadolinium enhancement (LGE) amount, extracellular volume fraction (ECV), and prevalence of sarcomere mutations compared with patients without NSVT. Among patients without NSVT, those with LGE (n = 46) had a higher total PVC (109 ± 332 vs 7 ± 13, P = .003) and PVC burden (0.114 ± 0.225 vs 0.008 ± 0.014%, P = .003) during 24‐hour Holter monitoring compared with others. The %LGE and global ECV were correlated with PVC burden (r = 0.377, P = .001; r = 0.401, P = .001). The optimal cutoff value for PVC number for LGE was 45 (37.0% and 100% sensitivity and specificity, respectively) with 0.733 of the area under the receiver operating characteristic‐curve (P < .001). Thick filament gene mutation was more prevalent in the higher PVC burden group (41.2% vs 16.7%, P = .048).

Conclusion

Total PVC burden is significantly related to increase in myocardial fibrosis in HCM patients without NSVT.
Differentiation of Cancer Stem Cells by Using Synthetic Small Molecules: Toward New Therapeutic Strategies against Therapy Resistance
Authors: Maucort Chloé , Di Giorgio Audrey , Azoulay Stéphane , Duca Maria
Published: August 2020

Despite the existing arsenal of anti‐cancer drugs, 10 million people die each year worldwide due to cancers; this highlights the need to discover new therapies based on innovative modes of action against these pathologies. Current chemotherapies are based on the use of cytotoxic agents, targeted drugs, monoclonal antibodies or immunotherapies that are able to reduce or stop the proliferation of cancer cells. However, tumor eradication is often hampered by the presence of resistant cells called cancer stem‐like cells or cancer stem cells (CSCs). Several strategies have been proposed to specifically target CSCs such as the use of CSC‐specific antibodies, small molecules able to target CSC signaling pathways or drugs able to induce CSC differentiation rendering them sensitive to classical chemotherapy. These latter compounds are the focus of the present review, which aims to report recent advances in anticancer‐differentiation strategies. This therapeutic approach was shown to be particularly promising for eradicating tumors in which CSCs are the main reason for therapeutic failure. This general view of the chemistry and mechanism of action of compounds inducing the differentiation of CSCs could be particularly useful for a broad range of researchers working in the field of anticancer therapies as the combination of compounds that induce differentiation with classical chemotherapy could represent a successful approach for future therapeutic applications.
Pectin: A Long‐Neglected Broad‐Spectrum Antibacterial
Authors: Ciriminna Rosaria , Fidalgo Alexandra , Meneguzzo Francesco , Presentato Alessandro , Scurria Antonino , Nuzzo Domenico , Alduina Rosa , Ilharco Laura M. , Pagliaro Mario
Published: August 2020

First reported in the late 1930s and partly explained in 1970, the antibacterial activity of pectin remained almost ignored until the late 1990s. The concomitant emergence of research on natural antibacterials and new usages of pectin polysaccharides, including those in medicine widely researched in Russia, has led to a renaissance of research into the physiological properties of this uniquely versatile polysaccharide ubiquitous in plants and fruits. By collecting scattered information, this study provides an updated overview of the subtle factors affecting the behaviour of pectin as an antimicrobial. Less‐degraded pectin extracted by acid‐free routes, we argue in the conclusions, will soon find applications from new treatments for polymicrobial infections to use as an implantable biomaterial in tissue and bone engineering.
4,4,16‐Trifluoropalmitate: Design, Synthesis, Tritiation, Radiofluorination and Preclinical PET Imaging Studies on Myocardial Fatty Acid Oxidation
Authors: Colombano Alessandro , Dall'Angelo Sergio , Kingston Lee , Grönberg Gunnar , Correia Claudia , Passannante Rossana , Baz Zuriñe , Morcillo Miguel Ángel , Elmore Charles S. , Llop Jordi , Zanda Matteo
Published: August 2020

Fatty acid oxidation (FAO) produces most of the ATP used to sustain the cardiac contractile work, although glycolysis is a secondary source of ATP under normal physiological conditions. FAO impairment has been reported in the advanced stages of heart failure (HF) and is strongly linked to disease progression and severity. Thus, from a clinical perspective, FAO dysregulation provides prognostic value for HF progression, the assessment of which could be used to improve patient monitoring and the effectiveness of therapy. Positron emission tomography (PET) imaging represents a powerful tool for the assessment and quantification of metabolic pathways in vivo. Several FAO PET tracers have been reported in the literature, but none of them is in routine clinical use yet. Metabolically trapped tracers are particularly interesting because they undergo FAO to generate a radioactive metabolite that is subsequently trapped in the mitochondria, thus providing a quantitative means of measuring FAO in vivo. Herein, we describe the design, synthesis, tritium labelling and radiofluorination of 4,4,16‐trifluoro‐palmitate (1) as a novel potential metabolically trapped FAO tracer. Preliminary PET‐CT studies on [18F]1 in rats showed rapid blood clearance, good metabolic stability – confirmed by using [3H]1 in vitro – and resistance towards defluorination. However, cardiac uptake in rats was modest (0.24±0.04 % ID/g), and kinetic analysis showed reversible uptake, thus indicating that [18F]1 is not irreversibly trapped.
Frequency and clinicopathologic associations of DNA mismatch repair protein deficiency in ampullary carcinoma: Routine testing is indicated
Authors: Xue Yue , Balci Serdar , Aydin Mericoz Cisel , Taskin Orhun C. , Jiang Hongmei , Pehlivanoglu Burcin , Muraki Takashi , Memis Bahar , Saka Burcu , Kim Grace E. , Bandopadhyay Sudeshna , Knight Jessica , El‐Rayes Bassel F. , Sarmiento Juan , Reid Michelle D. , Erkan Mert , Basturk Olca , Adsay Volkan
Published: August 2020

Background

The significance of DNA mismatch repair (MMR) deficiency in ampullary cancers (ACs) has not been established.

Methods

In total, 127 ACs with invasive carcinomas measuring ≥3 mmthat had adequate tissue were analyzed immunohistochemically.

Results

MMR loss was detected in 18% of ACs (higher than in colorectal cancers). Twelve tumors with MLH1‐PMS2 loss were negative for BRAF V600E mutation, suggesting a Lynch syndrome association. MMR‐deficient tumors (n = 23), comparedwith MMR‐intact tumors (n = 104), showed a striking male predominance (male:female ratio, 4.7). Although the deficient tumors had slightly larger invasion size (2.7 vs 2.1 cm), they also had more expansile growth and less invasiveness, including less perineural invasion, and they ultimately had lower tumor (T) classification and less lymph node metastasis (30% vs 53%; P = .04). More important, patients who had MMR‐deficient tumors had better clinical outcomes, with a 5‐year overall survival rate of 68% versus 45% (P = .03), which was even more pronounced in those who had higher Tclassification (5‐year overall survival, 69% vs 34%; P = .04). MMR deficiencyhad a statistically significant association with medullary phenotype, pushing‐border invasion, and tumor‐infiltrating immune cells, and it occurred more frequently in ampullary‐duodenal type tumors. Programed cell death‐ligand 1 (PD‐L1) levels analyzed in the 22 MMR‐deficient ACs revealed that all medullary carcinomas were positive. Nonmedullary MMR‐deficient carcinomas expressed PD‐L1 in 33% of tumors cells according to the criteria for a combined positive score ≥1, but all were negative according to the tumor proportion score≥1 method.

Conclusions

In ACs, MMR deficiency is even more frequent (18%) than in colon cancer and often has a Lynch‐suggestive profile, thus routine testing is warranted. Male gender, pushing‐border infiltration, ampullary‐duodenal origin, medullary histology, and tumor‐related inflammation have a significantly higher association with MMR deficiency. MMR‐deficient tumors have less aggressive behavior. PD‐L1 expression is common in medullary‐phenotype ACs, thus immunotherapy should be considered at least for this group.
The value of a tiered cytology diagnostic reporting system in assessing the risk of malignancy in indeterminate serous effusions
Authors: Hou Tieying , Landon Gene , Stewart John , Roy‐Chowdhuri Sinchita
Published: August 2020

Background

The International System for Reporting Serous Fluid Cytopathology was recently proposed as a tiered structure to provide consistent reporting terminology for serous effusions. Because of the variation in reporting practices for indeterminate serous effusions, namely, the atypia of undetermined significance (AUS) and suspicious for malignancy (SFM) groups, the authors retrospectively reviewed cases in these 2 categories at their institution and determined the associated risk of malignancy (ROM).

Methods

Pleural, peritoneal, and pericardial effusions that were reported as AUS or SFM over a 1‐year period were reviewed, and their associated ROMs were calculated based on confirmation of malignancy by previous and/or subsequent fluid and/or tissue biopsy specimens from the same general location.

Results

In total, 145 AUS and 98 SFM serous effusion cases were identified. The AUS category was used when the cells in question lacked the requisite quantitative (cell number) and/or qualitative (morphologic) features for a definitive diagnosis. Immunohistochemistry (IHC) or flow cytometry (FCM) was available in 15% of cases (n = 22) with inconclusive results. The ROM based on 69 cases with available follow‐up results was 39%. In contrast, the SFM category demonstrated cells that were morphologically suspicious for malignancy but sparse, precluding IHC or FCM (n = 63; 64%) or yielding inconclusive results (n = 35; 36%). The ROM in the SFM category, based on follow‐up results of 61 cases, was 64%.

Conclusions

The ROM for SFM was significantly higher than that for AUS (P < .01), supporting separate diagnostic categories for these 2 groups.
Whole‐brain efferent and afferent connectivity of mouse ventral tegmental area melanocortin‐3 receptor neurons
Authors: Dunigan Anna I. , Swanson Andrew M. , Olson David P. , Roseberry Aaron G.
Published: August 2020

The mesolimbic dopamine (DA) system is involved in the regulation of multiple behaviors, including feeding, and evidence demonstrates that the melanocortin system can act on the mesolimbic DA system to control feeding and other behaviors. The melanocortin‐3 receptor (MC3R) is an important component of the melanocortin system, but its overall role is poorly understood. Because MC3Rs are highly expressed in the ventral tegmental area (VTA) and are likely to be the key interaction point between the melanocortin and mesolimbic DA systems, we set out to identify both the efferent projection patterns of VTA MC3R neurons and the location of the neurons providing afferent input to them. VTA MC3R neurons were broadly connected to neurons across the brain but were strongly connected to a discrete set of brain regions involved in the regulation of feeding, reward, and aversion. Surprisingly, experiments using monosynaptic rabies virus showed that proopiomelanocortin (POMC) and agouti‐related protein (AgRP) neurons in the arcuate nucleus made few direct synapses onto VTA MC3R neurons or any of the other major neuronal subtypes in the VTA, despite being extensively labeled by general retrograde tracers injected into the VTA. These results greatly contribute to our understanding of the anatomical interactions between the melanocortin and mesolimbic systems and provide a foundation for future studies of VTA MC3R neurons and the circuits containing them in the control of feeding and other behaviors.
Large Amplitude Torsions in Nitrotoluene Isomers Studied by Rotational Spectroscopy and Quantum Chemistry Calculations
Authors: Roucou Anthony , Goubet Manuel , Kleiner Isabelle , Bteich Sabath , Cuisset Arnaud
Published: August 2020

Rotational spectra of ortho‐nitrotoluene (2‐NT) and para‐nitrotoluene (4‐NT) have been recorded at low and room temperatures using a supersonic jet Fourier Transform microwave (MW) spectrometer and a millimeter‐wave frequency multiplier chain, respectively. Supported by quantum chemistry calculations, the spectral analysis of pure rotation lines in the vibrational ground state has allowed to characterise the rotational energy, the hyperfine structure due to the 14N nucleus and the internal rotation splittings arising from the methyl group. For 2‐NT, an anisotropic internal rotation of coupled −CH3 and −NO2 torsional motions was identified by quantum chemistry calculations and discussed from the results of the MW analysis. The study of the internal rotation splittings in the spectra of three NT isomers allowed to characterise the internal rotation potentials of the methyl group and to compare them with other mono‐substituted toluene derivatives in order to study the isomeric influence on the internal rotation barrier.
Rational Design of Fe2(μ‐PR2)2(L)6 Coordination Compounds Featuring Tailored Potential Inversion
Authors: Arrigoni Federica , Rizza Fabio , Vertemara Jacopo , Breglia Raffaella , Greco Claudio , Bertini Luca , Zampella Giuseppe , De Gioia Luca
Published: August 2020

It was recently discovered that some redox proteins can thermodynamically and spatially split two incoming electrons towards different pathways, resulting in the one‐electron reduction of two different substrates, featuring reduction potential respectively higher and lower than the parent reductant. This energy conversion process, referred to as electron bifurcation, is relevant not only from a biochemical perspective, but also for the ground‐breaking applications that electron‐bifurcating molecular devices could have in the field of energy conversion. Natural electron‐bifurcating systems contain a two‐electron redox centre featuring potential inversion (PI), i. e. with second reduction easier than the first. With the aim of revealing key factors to tailor the span between first and second redox potentials, we performed a systematic density functional study of a 26‐molecule set of models with the general formula Fe2(μ‐PR2)2(L)6. It turned out that specific features such as i) a Fe−Fe antibonding character of the LUMO, ii) presence of electron‐donor groups and iii) low steric congestion in the Fe's coordination sphere, are key ingredients for PI. In particular, the synergic effects of i)‐iii) can lead to a span between first and second redox potentials larger than 700 mV. More generally, the “molecular recipes” herein described are expected to inspire the synthesis of Fe2P2 systems with tailored PI, of primary relevance to the design of electron‐bifurcating molecular devices.
A Practical Guide for Structural Variation Detection in the Human Genome
Authors: Yang Lixing
Published: August 2020

Profiling genetic variants—including single nucleotide variants, small insertions and deletions, copy number variations, and structural variations (SVs)—from both healthy individuals and individuals with disease is a key component of genetic and biomedical research. SVs are large‐scale changes in the genome and involve breakage and rejoining of DNA fragments. They may affect thousands to millions of nucleotides and can lead to loss, gain, and reshuffling of genes and regulatory elements. SVs are known to impact gene expression and potentially result in altered phenotypes and diseases. Therefore, identifying SVs from the human genomes is particularly important. In this review, I describe advantages and disadvantages of the available high‐throughput assays for the discovery of SVs, which are the most challenging genetic alterations to detect. A practical guide is offered to suggest the most suitable strategies for discovering different types of SVs including common germline, rare, somatic, and complex variants. I also discuss factors to be considered, such as cost and performance, for different strategies when designing experiments. Last, I present several approaches to identify potential SV artifacts caused by samples, experimental procedures, and computational analysis. © 2020 Wiley Periodicals LLC.
Enzyme Immobilization in Covalent Organic Frameworks: Strategies and Applications in Biocatalysis
Authors: Oliveira Felipe L. , de S. França Alexandre , de Castro Aline Machado , Alves de Souza Rodrigo O. M. , Esteves Pierre M. , Gonçalves Raoni Schroeder B.
Published: August 2020

The development of efficient catalytic systems is a fundamental aspect for the straightforward production of chemicals. During the last years, covalent organic frameworks (COFs) emerged as an exciting class of organic nanoporous materials. Due to their pre‐designable structure, they can be prepared with distinct physicochemical characteristics, specific pore sizes, and tunable functional groups. Moreover, associated with their stability in different media, these materials are considered promising supports for enzyme immobilization. Herein, it is highlighted the recent literature of enzyme immobilization in COFs, the main immobilization strategies, and the catalytic applications of these composites.
How one large outpatient practice moved to home‐based telemedicine services
Authors: Knopf Alison
Published: August 2020

The pandemic has created the need for telehealth, not only for established patients but for youth who develop problems during the crisis, and this need has been turned into an opportunity, with one provider developing a “roadmap” for establishing what it called home‐based telemental health, or HB‐TMH. Psychiatrists in Seattle, at the University of Washington, the Seattle Children's Research Institute, and Seattle Children's Hospital, report on their rapid implementation for TMH during — not after — future crises when community resources are not available.
A Carbon Catalyst Co‐Doped with P and N for Efficient and Selective Oxidation of 5‐Hydroxymethylfurfural into 2,5‐Diformylfuran
Authors: Zhang Huifa , Clark James H. , Geng Tong , Zhang Huixian , Cao Fahai
Published: August 2020

A newly designed N and P co‐doped carbon material has been developed to catalyze the conversion of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandialdehyde (DFF) with unprecedented yield and selectivity and demonstrating a synergistic effect between the heteroatoms. The desired catalyst was first synthesized via a pyrolysis method using urea as the nitrogen and carbon source followed by calcination with phytic acid solution as the phosphorus source. The mass ratio of phytic acid to C3N4 and calcination temperature were varied to investigate their effects on catalyst synthesis and microstructure as well as subsequent catalytic activity in simple reaction systems under oxygen. The effect of reaction conditions on the final HMF conversion and DFF selectivity were also investigated systematically. The P−C−N‐5‐800 catalyst obtained with the optimized annealing temperature of 800 °C and mass ratio of phytic acid/C3N4 of 5 enabled a 99.5 % DFF yield at 120 °C for 9 h under 10 bar oxygen pressure, being the highest among any reported metal‐free heterogeneous catalyst to date. The excellent performance of P−C−N‐5‐800 could be ascribed to the synergy between N and P heteroatoms as well as the high content of graphitic‐N and the P−C species within the carbon structure. Reusability studies show that the P−C−N‐5‐800 catalyst was stable and reusable without deactivation. These results strongly suggest that P−C−N‐5‐800 is a promising catalyst for large‐scale production of DFF in a green manner.
Understanding the Molecular Structure of the Elastic and Thermoreversible AlCl3 : Urea/Polyethylene Oxide Gel Electrolyte
Authors: Miguel Álvaro , Fornari Rocco Peter , García Nuria , Bhowmik Arghya , Carrasco‐Busturia David , García‐Lastra Juan Maria , Tiemblo Pilar
Published: August 2020

It is possible to prepare elastic and thermoreversible gel electrolytes with significant electroactivity by dissolving minimal weight fractions of ultra‐high molecular weight polyethylene oxide (UHMW PEO) in an aluminum deep eutectic solvent (DES) electrolyte composed of AlCl3 and urea at a molar ratio of 1.5 : 1 (AlCl3/urea). The experimental vibrational spectra (FTIR and Raman) provide valuable information on the structure and composition of the gel electrolyte. However, the complexity of this system requires computational simulations to help interpretation of the experimental results. This combined approach allows us to elucidate the speciation of the DES liquid electrolyte in the gel and how it interacts with the polymer chains to give rise to an elastic network that retains the electroactivity of the liquid electrolyte to a very great extent. The observed reactions occur between the ether in the polymer and both the amine groups in urea and the aluminum species. Thus, similar elastomeric gels may likely be prepared with other aluminum liquid electrolytes, making this procedure an effective way to produce families of gel aluminum electrolytes with tunable rheology and electroactivity.
Bio‐Based Cycloalkanes: The Missing Link to High‐Performance Sustainable Jet Fuels
Authors: Muldoon Jake A. , Harvey Benjamin G.
Published: August 2020

The development of sustainable energy solutions that reduce global carbon emissions, while maintaining high living standards, is one of the grand challenges of the current century. Transportation fuels are critical to economic development, globalization, and the advancement of society. Although ground vehicles and small aircraft are beginning a slow transition toward electric propulsion with energy sourced from solar radiation or wind, the extreme power requirements of jet aircraft require a more concentrated source of energy that is conveniently provided by liquid hydrocarbon fuels. This Review describes recent efforts to develop efficient routes for the conversion of crude biomass sources (e. g., lignocellulose) to cycloalkanes. These cycloalkanes impart advantageous properties to jet fuels, including increased density, higher volumetric heat of combustion, and enhanced operability. The combination of bio‐based cycloalkanes and synthetic paraffinic kerosenes allows for the preparation of 100 % bio‐based fuels that can outperform conventional petroleum‐based fuels. In this Review methods are described that convert biomass‐derived small molecules, including furfural, furfuryl alcohol, 5‐hydroxymethylfurfural, cyclic ketones, phenolics, acyclic ketones, cyclic alcohols, furans, esters, and alkenes to high‐density cycloalkanes. In addition to describing the chemical transformations and catalysts that have been developed to efficiently produce various cycloalkanes, this Review includes summaries of key fuel properties, which highlight the ability to generate fuels with customized performance metrics. This work is intended to inspire other researchers to study the conversion of sustainable feedstocks to full‐performance aviation fuels. An acceleration of this research is critical to reducing the carbon footprint of commercial and military aviation on a timescale that will help blunt the impacts of global warming.
A novel flash‐like all‐metal‐oxide semiconductor analog‐to‐digital converter suitable for system on chips systems
Authors: Abdalla Yasser S.
Published: August 2020

The analog‐to‐digital converters (ADCs) play a very important role in electronic products, radar, communication systems and signal processing, to name such a few. In this paper, a novel all‐metal‐oxide semiconductor (MOS) flash‐like analog‐to‐digital converter (FLADC) that consists of five stages is proposed. The design was performed using only MOS transistors, and the proposed ADC works in a way similar to the conventional flash ADC. According to the proposed ADC, there is no need for the comparators used in the conventional flash ADCs, thus resulting in a reduction in both the transistor count and the power consumption. The sound operation and the superiority of the proposed ADC compared to previous works is verified by simulation using the 0.13‐μm complementary MOS (CMOS) technology with a power‐supply voltage, VDD, of 1.2 V. The simulation has been conducted on a 5‐bit FLADC that is built by 276 MOS transistors only which is approximately 32% of the transistor count of the corresponding conventional flash ADC and has no resistors. According to the simulation results, the proposed 5‐bit FLADC consumes 3.23 mW at sampling rate of 0.5 GS/s.
Reintroduced grazers and prescribed fire effects on beetle assemblage structure and function in restored grasslands
Authors: Nelson Melissa , Hosler Sheryl C. , Boetzl Fabian A. , Jones Holly P. , Barber Nicholas A.
Published: August 2020

Ecological restoration seeks to reestablish functioning ecosystems, but planning and evaluation often focus on taxonomic community structure and neglect consumers and their functional roles. The functional trait composition of insect assemblages, which make up the majority of animal diversity in many systems, can reveal how they are affected by restoration management and the consequences for ecosystem function. We sampled ground beetle (Coleoptera: Carabidae) assemblages in restored tallgrass prairies varying in management with prescribed fire and reintroduced American bison (Bison bison) to describe their taxonomic and functional trait structure. We also measured seed and arthropod predation to relate management, beetle assemblage characteristics, and function, and to test if function is maximized by trait diversity, dominant trait values, or beetle abundance. Beetle assemblages primarily varied with restoration age, declining over time in richness and both taxonomic and functional diversity, but bison presence also influenced taxonomic composition. Prescribed fire reduced seed predation in summer and arthropod predation in fall. Although seed predation was unrelated to beetle assemblages, arthropod predation was greater in sites with higher abundances of carnivorous ground beetles. The relatively weak impacts of fire and bison on functional assemblage structure is a promising sign that these management disturbances, aimed at supporting a diverse native plant community, are not detrimental to beetle assemblages. The significance of reduced predator function following prescribed fire will depend on the restoration context and whether seed or arthropod predation relates to management goals.
Impact of binge eating during pregnancy on gestational weight gain and postpartum weight retention among women with gestational diabetes mellitus: LINDA‐Brasil
Authors: Silvani Juliana , Schmidt Maria Inês , Zajdenverg Lenita , Galliano Leony Morgana , Antunes Nunes Maria Angélica
Published: August 2020

Objective

Binge eating (BE) is associated with gestational weight gain, which is a risk factor for gestational diabetes (GDM). Little is known about this association in women with GDM. To evaluate the relationship of BE in pregnancy with gestational weight gain, BE at postpartum and postpartum weight retention in women with GDM.

Method

Lifestyle INtervention for Diabetes prevention After pregnancy (LINDA‐Brasil) is a multicenter cohort study with 1,958 women with GDM. BE was assessed by interview during recruitment in pregnancy and at a phone interview at ~4 months postpartum. Gestational weight gain was classified according to the 2009 Institute of Medicine (IOM) recommendations. Poisson regression with robust variance was used to estimate adjusted relative risks (RR).

Results

Prevalence of BE was 31.6% (95% confidence interval [CI] 29.5–33.6%) during pregnancy and 30.0% (95% CI 28.0–32.1%) at postpartum. The risk of exceeding the IOM's recommendation for gestational weight gain was 45% higher (RR 1.45, 95% CI 1.29–1.63) in women who had BE during pregnancy compared to those who did not. The risk of having postpartum weight retention above the 75th percentile was 33% higher (RR 1.33, 95% CI 1.10–1.59) among those with BE compared to those without.

Discussion

Among these women with GDM, BE was frequent and was associated with excessive gestational weight gain and weight retention at postpartum. Thus, given the vulnerability of these periods of the life cycle, tracking this eating behavior is important for the management of gestational weight gain and for the prevention of excessive postpartum retention.
The external ear morphology and presence of tragi in Australian marsupials
Authors: Stannard Hayley J. , Dennington Kathryn , Old Julie M.
Published: August 2020

Multiple studies have described the anatomy and function of the external ear (pinna) of bats, and other placental mammals, however, studies of marsupial pinna are largely absent. In bats, the tragus appears to be especially important for locating and capturing insect prey. In this study, we aimed to investigate the pinnae of Australian marsupials, with a focus on the presence/absence of tragi and how they may relate to diet. We investigated 23 Australian marsupial species with varying diets. The pinnae measurements (scapha width, scapha length) and tragi (where present) were measured. The interaural distance and body length were also recorded for each individual. Results indicated that all nectarivorous, carnivorous, and insectivorous species had tragi with the exception of the insectivorous striped possum (Dactylopsila trivirgata), numbat (Myrmecobius fasciatus), and nectarivorous sugar glider (Petaurus breviceps). No herbivorous or omnivorous species had tragi. Based on the findings in this study, and those conducted on placental mammals, we suggest marsupials use tragi in a similar way to placentals to locate and target insectivorous prey. The Tasmanian devil (Sarcophilus harrisii) displayed the largest interaural distance that likely aids in better localization and origin of noise associated with prey detection. In contrast, the smallest interaural distance was exhibited by a macropod. Previous studies have suggested the hearing of macropods is especially adapted to detect warnings of predators made by conspecifics. While the data in this study demonstrate a diversity in pinnae among marsupials, including presence and absence of tragi, it suggests that there is a correlation between pinna structure and diet choice among marsupials. A future study should investigate a larger number of individuals and species and include marsupials from Papua New Guinea, and Central and South America as a comparison.
Introduced beaver improve growth of non‐native trout in Tierra del Fuego, South America
Authors: Arismendi Ivan , Penaluna Brooke E. , Jara Carlos G.
Published: August 2020

Species introductions threaten ecosystem function worldwide, and interactions among introduced species may amplify their impacts. Effects of multiple invasions are still poorly studied, and often, the mechanisms underlying potential interactions among invaders are unknown. Despite being a remote and well‐conserved area, the southern portion of South America has been greatly impacted by invasions of both the American beaver (Castor canadensis) and Brown Trout (Salmo trutta fario). Here, we compared growth, condition, diet, and stable isotopes of sulfur δ34S, nitrogen δ15N, and carbon δ13C for stream‐living Brown Trout from streams with (n = 6) and without (n = 6) beaver in Tierra del Fuego, Chile. We show that beaver may facilitate the success of trout by positively influencing fish growth. Beaver indirectly provide greater food subsidies (i.e., macroinvertebrate abundances) by modifying the local aquatic environment through active dam and lodge building suggesting a one‐way positive interaction. Trout in beaver‐influenced streams occupied a slightly higher trophic level with more depleted sulfur and carbon isotopic ratios suggesting that food web pathways rely on secondary production from autochthonous origin. Trout in beaver‐influenced streams had a wider dietary breadth with diptera and amphipoda as the prey items providing most of the energy, whereas in streams without beaver, trichoptera were the main source of energy for trout. Ultimately, we find that these two species, which have never co‐occurred naturally, bring about the same ecosystem function and the beneficial influences in their native ranges as in invaded systems.
Assessing the genetic diversity of farmed and wild Rufiji tilapia (Oreochromis urolepis urolepis) populations using ddRAD sequencing
Authors: Nyinondi Christer S. , Mtolera Matern S. P. , Mmochi Aviti J. , Lopes Pinto Fernando A. , Houston Ross D. , de Koning Dirk J. , Palaiokostas Christos
Published: August 2020

Rufiji tilapia (Oreochromis urolepis urolepis) is an endemic cichlid in Tanzania. In addition to its importance for biodiversity conservation, Rufiji tilapia is also attractive for farming due to its high growth rate, salinity tolerance, and the production of all‐male hybrids when crossed with Nile tilapia (Oreochromis niloticus). The aim of the current study was to assess the genetic diversity and population structure of both wild and farmed Rufiji tilapia populations in order to inform conservation and aquaculture practices. Double‐digest restriction‐site‐associated DNA (ddRAD) libraries were constructed from 195 animals originating from eight wild (Nyamisati, Utete, Mansi, Mindu, Wami, Ruaha, Kibasira, and Kilola) and two farmed (Bwawani and Chemchem) populations. The identified single nucleotide polymorphisms (SNPs; n = 2,182) were used to investigate the genetic variation within and among the studied populations. Genetic distance estimates (Fst) were low among populations from neighboring locations, with the exception of Utete and Chemchem populations (Fst = 0.34). Isolation‐by‐distance (IBD) analysis among the wild populations did not detect any significant correlation signal (r = .05; p‐value = .4) between the genetic distance and the sampling (Euclidean distance) locations. Population structure and putative ancestry were further investigated using both Bayesian (Structure) and multivariate approaches (discriminant analysis of principal components). Both analysis indicated the existence of three distinct genetic clusters. Two cross‐validation scenarios were conducted in order to test the efficiency of the SNP dataset for discriminating between farmed and wild animals or predicting the population of origin. Approximately 95% of the test dataset was correctly classified in the first scenario, while in the case of predicting for the population of origin 68% of the test dataset was correctly classified. Overall, our results provide novel insights regarding the population structure of Rufiji tilapia and a new database of informative SNP markers for both conservation management and aquaculture activities.
Leaf size variations in a dominant desert shrub, Reaumuria soongarica, adapted to heterogeneous environments
Authors: Fan Xingke , Yan Xia , Qian Chaoju , Bachir Daoura Goudia , Yin Xiaoyue , Sun Peipei , Ma Xiao‐Fei
Published: August 2020

The climate in arid Central Asia (ACA) has changed rapidly in recent decades, but the ecological consequences of this are far from clear. To predict the impacts of climate change on ecosystem functioning, greater attention should be given to the relationships between leaf functional traits and environmental heterogeneity. As a dominant constructive shrub widely distributed in ACA, Reaumuria soongarica provided us with an ideal model to understand how leaf functional traits of desert ecosystems responded to the heterogeneous environments of ACA. Here, to determine the influences of genetic and ecological factors, we characterized species‐wide variations in leaf traits among 30 wild populations of R. soongarica and 16 populations grown in a common garden. We found that the leaf length, width, and leaf length to width ratio (L/W) of the northern lineage were significantly larger than those of other genetic lineages, and principal component analysis based on the in situ environmental factors distinguished the northern lineage from the other lineages studied. With increasing latitude, leaf length, width, and L/W in the wild populations increased significantly. Leaf length and L/W were negatively correlated with altitude, and first increased and then decreased with increasing mean annual temperature (MAT) and mean annual precipitation (MAP). Stepwise regression analyses further indicated that leaf length variation was mainly affected by latitude. However, leaf width was uncorrelated with altitude, MAT, or MAP. The common garden trial showed that leaf width variation among the eastern populations was caused by both local adaptation and phenotypic plasticity. Our findings suggest that R. soongarica preferentially changes leaf length to adjust leaf size to cope with environmental change. We also reveal phenotypic evidence for ecological speciation of R. soongarica. These results will help us better understand and predict the consequences of climate change for desert ecosystem functioning.