bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulus package includes 42 CFR Part 2 provisions
Authors: Knopf Alison
Published: March 2020

The language in the stimulus package, as of March 26, revises 42 CFR Part 2 (confidentiality of substance use disorder patient records requiring patient consent before release), eliminating the consent provisions – allowing patients to give consent only once: “it shall be permissible for a patient's prior written consent to be given once for all such future uses or disclosures for purposes of treatment, payment, and health care operations, until such time as the patient revokes such consent in writing.”While not full alignment with the Health Insurance Portability and Accountability Act (HIPAA), it is bad news for confidentiality. Many programs probably require consent before admitting patients to treatment. The vague “health care operations” is included as a party that can get information redisclosed. If the House and the President signs off, the new law goes into effect immediately. H. Westley Clark, M.D., J.D., Dean's Executive Professor at Santa Clara University and former director of the Center for Substance Abuse Treatment at the Substance Abuse and Mental Health Services Administration said the pending NPRM on 42 CFR Part 2 from SAMHSA should be suspended, that 42 CFR Part 2 should be formally moved from SAMHSA to the Office of Civil Rights (OCR) of the Department of Health and Human Services since OCR has the function to collect data, monitor breaches, and impose penalties.” In addition, stakeholders should “ask what the new 42 CFR part 2 look like with the proposed changes which include the consent provisions, the breach notification provisions, the penalty provisions and all the other bells and whistles.” The bill was passed unanimously by the Senate March 25, and was scheduled to go to the House of Representatives for a vote March 27, after which President Trump was expected to sign it.
Microstructure and Fatigue of Ultrafine‐Grained Ferritic/Martensitic Steel
Authors: Nikitina Marina , Islamgaliev Rinat , Ganeev Artur , Sitdikov Vil
Published: March 2020

The impact of equal‐channel angular pressing in combination with additional heat treatment on microstructure and fatigue of ferritic/martensitic steel is investigated. It is shown that the formation of both the ultrafine‐grained (UFG) structure with an average grain size of about 0.8 μm and the enhanced share of boundaries with the coincidence site lattice (CSL) relationships (the CSL boundaries) leads to an increase in the fatigue endurance limit of more than 50% compared with samples after tempering. Dynamic strain aging is found in the fracture zone of the UFG of samples after fatigue tests. The influence of structural parameters on the fatigue endurance limit of the UFG samples is discussed.
Antifouling Field‐Effect Transistor Sensing Interface Based on Covalent Organic Frameworks
Authors: Yang Lei , Jin Yuqing , Wang Xuejun , Yu Bin , Chen Renzhong , Zhang Cong , Zhao Yan , Yu Yuguo , Liu Yunqi , Wei Dacheng
Published: March 2020

Due to the complexity of detection environments, field‐effect transistor (FET) sensors face the problem of fouling in practical applications. Existing antifouling strategies normally block the sensing sites and decrease the detection sensitivity. It remains a great challenge to achieve antifouling and sensitive detection. Here, a strategy is developed to use covalent organic frameworks (COFs) as the sensing interface. Owing to their unique crystalline mesoporous structure, the COFs not only encapsulate and prevent the channel from being fouled but also provide a large specific surface area modified with receptors. This approach enables the detection of 10−10 m Hg2+ within 50 ms in a ≈30 ppm poly‐(3,4‐ethylenedioxythiophene):poly‐(styrenesulfonate) solution and weak neural potential signals in complex bio‐environment, which is among the best performance for antifouling FET sensors. The COF interface enables highly sensitive and antifouling detection together with a fast response and large response range, which shows its great potential in high‐performance antifouling FET sensors.
KIT‐related piebaldism in a Chinese girl
Authors: Zhu Lei , Yang Chao , Zhong Wei , Huang Yu‐Qi , Zhang Qi , Xu Wen‐Cong , Chen Yong‐Feng
Published: March 2020

Piebaldism is a rare, autosomal dominant and congenital pigmentary disorder characterized by stable depigmentation of the skin and white forelock. Mutations in KIT or SNAI2 genes result in piebaldism. Most individuals with piebaldism have a family history of the disorder. Herein, we report a 5‐month‐old Chinese girl with severe piebaldism but no family history thereof. She has white forelock and large patches of depigmentation in the jaw, central anterior trunk, perineum and extremities. We performed whole‐exome and Sanger sequencing and identified a de novo KIT mutation (NM_000222.2: c.2657G>A, p.Gly886Val) in exon 18 of KIT in the proband. Currently, this mutation is located in the most extreme C‐terminal of the tyrosine kinase domain 2 of the KIT gene amongst all reported mutations and causes a severe clinical phenotype. We further reviewed literature on piebaldism and summarized 79 KIT gene mutations that lead to this disease. Our study may expand knowledge on the genotype–phenotype correlation in piebaldism and serve as a reference for genetic counseling and prenatal diagnosis of affected families.
Planar Chiral Organoboranes with Thermoresponsive Emission and Circularly Polarized Luminescence: Integration of Pillar[5]arenes with Boron Chemistry
Authors: Chen Jin‐Fa , Yin Xiaodong , Wang Bowen , Zhang Kai , Meng Guoyun , Zhang Songhe , Shi Yafei , Wang Nan , Wang Suning , Chen Pangkuan
Published: March 2020

Enantiopure molecules based on macrocyclic architecture are unique for applications in enantioselective host‐guest recognition, chiral sensing and asymmetric catalysis. Taking advantage of the chiral transfer from the intrinsically planar chirality of pillar[5]arenes, we herein present an efficient and straightforward approach to achieve early examples of highly luminescent chiral systems (P5NN and P5BN). The optical resolution of their enantiomers has been carried out via preparative chiral HPLC, which was ascribed to the molecular functionalization of pillar[5]arenes with π‐conjugated, sterically bulky triarylamine (Ar3N) as an electron donor and triarylborane (Ar3B) as an acceptor. This crucial design enabled investigations of the chiroptical properties, including circular dichroism (CD) and circularly polarized luminescence (CPL) in the solid state. The intramolecular charge transfer (ICT) nature in P5BN afforded an interesting thermochromic shift of the emission over a wide temperature range.
Mehrfache katalytische C‐H‐Bindungsfunktionalisierungen in der Naturstoffsynthese
Authors: Baudoin Olivier
Published: March 2020

Während des letzten Jahrzehnts wurde die mehrfach katalytische C‐H‐Funktionalisierung erfolgreich in der Synthese von Naturstoffen angewandt, um die Anzahl der Synthesestufen zu reduzieren, die Gesamtausbeute zu erhöhen, sowie leichter zugängliche Ausgangsverbindungen zu verwenden. In diesem Kurzaufsatz werden ausgewählte Beispiele gezeigt, in welchen die mehrfach C‐H‐Funktionalisierung auf verschiedene konzeptuelle Weisen eingesetzt wird. Zuerst werden lineare Synthesen besprochen, in welchen die mehrfache C‐H‐Funktionalisierung entweder an einfachen (hetero)zyklischen Strukturen, als späte Modifikationen oder zum Aufbauen von polyzyklischen Systemen Verwendung findet. Anschließend wird demonstriert, wie der Gebrauch von mehrfachen C‐H‐Funktionalisierungen als strategisches Werkzeug in konvergenten Synthesen angewandt werden kann, um komplexe Fragmente zu erhalten und zu kuppeln. Informationen über die Skalierbarkeit der verwendeten Methoden ist gegeben, wenn verfügbar. Die ausgewählten Beispiele zeigen, dass die Verwendung von mehrfachen C‐H‐Funktionalisierungsstrategien eine wichtige Rolle in der Gestaltung von zukünftigen Synthesen funktioneller und komplexer Moleküle mit verbesserter Nachhaltigkeit sein sollten.
Ultraschnelle und kostengünstige Produktion von hochwertigem Graphen
Authors: Sun Zhuxing , Hu Yun Hang
Published: March 2020

Die schnelle, großskalige und kostengünstige Produktion von hochwertigem Graphen ist stets eine große Herausforderung geblieben, auch wenn einige Ansätze das Potenzial für die Massensynthese von Graphen aufgezeigt haben. Erst kürzlich erzielten Tour und Mitarbeiter einen großen Durchbruch (Nature 2020, 577, 647–651): In nur einer Sekunde wurde aus kohlenstoffreichen Spezies durch kostengünstige Flash‐Joule‐Erwärmung mit einem geringen Energieaufwand von 7.2 kJ pro Gramm Graphen auf einfache Weise exfoliertes und hochkristallines Graphen hergestellt. Solch ein ultraschneller, wirtschaftlicher und skalierbarer Prozess für die Herstellung von hochwertigem Graphen kann als ein Meilenstein im Graphensektor angesehen werden und wird in diesem Highlight vorgestellt.
Tracking Structural Evolution during Symmetry‐Breaking Charge Separation in Quadrupolar Perylene Bisimide with Time‐Resolved Impulsive Stimulated Raman Spectroscopy
Authors: Kim Woojae , Kim Taeyeon , Kang Seongsoo , Hong Yongseok , Würthner Frank , Kim Dongho
Published: March 2020

Elucidating structural roles in photoinduced charge transfer is indispensable, as nuclear rearrangements are simultaneously usually involved in the dynamics. However, it is hard to evaluate whether the structural changes occur or not by using conventional time‐resolved electronic spectroscopy. Here, time‐resolved impulsive stimulated Raman spectroscopy is applied to record the evolution of vibrational snapshots during charge‐separation dynamics of donor–acceptor–donor‐type quadrupolar perylene bisimide in real time. Drastic frequency shifts were observed for several Raman bands with their population kinetics, thus symmetry‐breaking charge separation accompanies significant structural changes, as supported by (TD)‐DFT calculations. A comparison between time‐resolved Raman spectra of the neutral S1 state and the radical anion species shows that the spectral signatures, especially in high‐frequency regions, provide important clues to bond length alternation patterns in the PBI core.
Ketones as Molecular Co‐catalysts for Boosting Exciton‐Based Photocatalytic Molecular Oxygen Activation
Authors: Wang Hui , Jiang Shenlong , Liu Wenxiu , Zhang Xiaodong , Zhang Qun , Luo Yi , Xie Yi
Published: March 2020

Excitonic processes in semiconductors open up the possibility for pursuing photocatalytic organic synthesis. However, the insufficient spin relaxation and robust nonradiative decays in semiconductors place restrictions on both quantum yield and selectivity of these reactions. Herein, by taking polymeric carbon nitride (PCN)/acetone as a prototypical system, we propose that extrinsic aliphatic ketones can serve as molecular co‐catalysts for promoting spin‐flip transition and suppressing non‐radiative energy losses. Spectroscopic investigations indicate that hot excitons in PCN can be transferred to ketones, while triplet excitons in ketones can be transferred to PCN. As such, the PCN/ketone systems exhibit considerable triplet‐exciton accumulation and extended visible‐light response, leading to excellent performance in exciton‐based photocatalysis, such as singlet oxygen generation. This work provides a fundamental understanding of energy harvesting in semiconductor/molecule systems, and paves the way for optimizing exciton‐based photocatalysis via molecular co‐catalyst design.
Unusual Skeletal Reorganization of Oxetanes for the Synthesis of 1,2‐Dihydroquinolines
Authors: Wang Guannan , Huang Hai , Guo Wengang , Qian Chenxiao , Sun Jianwei
Published: March 2020

Skeletal reorganization is a type of fascinating transformations owing to their intriguing mechanisms and utility in complex molecule synthesis. However, only a limited amount of examples are known for most functional groups. Herein, we describe such an unusual process of oxetanes. In the presence of In(OTf)3as catalyst, oxetane‐tethered anilines reacted unexpectedly to form 1,2‐dihydroquinolines. This process not only provides expedient access to dihydroquinolines, but also represents a new reaction of oxetane. Mechanistically, it is believed that the reaction proceeds through initial nitrogen attack rather than arene attack followed by a series of bond cleavage and formation events. Control experiments provided important insights into the mechanism.
Pigmentation Chemistry and Radical‐Based Collagen Degradation in Alkaptonuria and Osteoarthritic Cartilage
Authors: Chow Wing Ying , Norman Brendan P. , Roberts Norman B. , Ranganath Lakshminarayan R. , Teutloff Christian , Bittl Robert , Duer Melinda J. , Gallagher James A. , Oschkinat Hartmut
Published: March 2020

Alkaptonuria (AKU) is a rare disease characterized by high levels of homogentisic acid (HGA); patients suffer from tissue ochronosis: dark brown pigmentation, especially of joint cartilage, leading to severe early osteoarthropathy. No molecular mechanism links elevated HGA to ochronosis; the pigment's chemical identity is still not known, nor how it induces joint cartilage degradation. Here we give key insight on HGA‐derived pigment composition and collagen disruption in AKU cartilage. Synthetic pigment and pigmented human cartilage tissue both showed hydroquinone‐resembling NMR signals. EPR spectroscopy showed that the synthetic pigment contains radicals. Moreover, we observed intrastrand disruption of collagen triple helix in pigmented AKU human cartilage, and in cartilage from patients with osteoarthritis. We propose that collagen degradation can occur via transient glycyl radicals, the formation of which is enhanced in AKU due to the redox environment generated by pigmentation.
Asymmetric Reductive and Alkynylative Heck Bicyclization of Enynes to Access Conformationally Restricted Aza[3.1.0]bicycles
Authors: Huang Xiaolei , Nguyen Minh Hieu , Pu Maoping , Zhang Luoqiang , Chi Yonggui Robin , Wu Yun‐Dong , Zhou Jianrong Steve
Published: March 2020

Conformationally restricted azabicycles are becoming increasingly important in medicinal research. Asymmetric Heck bicyclization of enynes proceeds to give medicinally useful aza[3.1.0] and aza[4.1.0] bicycles with excellent enantioselectivity. The key organopalladium species after bicyclization can be trapped by silanes and terminal alkynes.
A Structurally Robust Chiral Borate Ion: Molecular Design, Synthesis, and Asymmetric Catalysis
Authors: Uraguchi Daisuke , Ueoka Fumito , Tanaka Naoya , Kizu Tomohito , Takahashi Wakana , Ooi Takashi
Published: March 2020

Catalysis by chiral weakly‐coordinating anions (WCAs) remains underdeveloped due to the lack of a molecular design strategy for exploiting their characteristics, such as the non‐nucleophilic nature. Here, we report the development of a chiral borate ion comprising an O,N,N,O‐tetradentate backbone, which ensures hitherto unattainable structural robustness. Upon pairing with a proton, the hydrogen borate acts as an effective catalyst for the asymmetric Prins‐type cyclization of vinyl ethers, providing access to structurally and stereochemically defined dihydropyrans. The key to selectivity control is the distinct ability of the borate ion to discriminate the prochiral faces of the acyclic oxonium ion intermediate and dictate the regiochemical outcome. We anticipate that this study paves the way for exploring the untapped potential of WCA catalysis for selective chemical synthesis.
Lasing from an Organic Micro‐Helix
Authors: Sun Chun‐Lin , Li Jun , Song Qi‐Wei , Ma Yu , Zhang Ze‐Qi , De Jian‐Bo , Liao Qing , Fu Hongbing , Yao Jiannian , Zhang Hao‐Li
Published: March 2020

Organic solid‐state semiconductor lasers are attracting ever‐increasing interest for their potential application in future photonic circuits. Despite the great progress made in recent years, an organic laser from 3D chiral structures has not been achieved. Now, the first example of an organic nano‐laser from the micro‐helix structure of an achiral molecule is presented. Highly regular micro‐helixes with left/right‐handed helicity from a distyrylbenzene derivative (HM‐DSB) were fabricated and characterized under microscope spectrometers. These chiral micro‐helixes exhibit unique photonic properties, including helicity‐dependent circularly polarized luminescence (CPL), periodic optical waveguiding, and length‐dependent amplified spontaneous emission (ASE) behavior. The successful observation of laser behavior from the organic micro‐helix extends our understanding to morphology chirality of organic photonic materials and provides a new design strategy towards chiral photonic circuits.
Follow‐up imaging observations of comet 2I/Borisov
Authors: Mugrauer Markus , Bischoff Richard , Stenglein Wolfgang , Trautmann Julius , Baghdasaryan Baghdasar , Schlagenhauf Saskia
Published: March 2020

Follow‐up imaging observations of the first detected interstellar comet 2I/Borisov are presented, which were carried out with the Schmidt‐Teleskop‐Kamera at the University Observatory Jena in 11 observing epochs in October and November 2019. The orbital solution of the comet, derived from the obtained astrometric measurements, confirms its highly eccentric (e = 3.3570 ± 0.0006) and inclined (i = 44.0524 ± 0.0004°) orbit, that proves the interstellar origin of the comet. According to our best‐fitting orbital solution, comet 2I/Borisov reaches its perihelion on 2019 Dec 8 (q = 2.0066 au) and its closest encounter with Earth on 2019 Dec 28 (Δmin = 1.9368 au). The distance corrected brightness of the nucleus of the comet clearly exhibits a linear correlation with its phase angle. The slope of this correlation indicates the activity of the comet, which is also detected in deep imaging data, taken in five observing epochs, showing the coma and the tail of the comet. During our observing campaign the coma of comet 2I/Borisov exhibits on average a diameter of (4.57 ± 0.38) · 104 km, and the length of the tail of the comet measures (1.52 ± 0.12) · 105 km, assuming an anti‐solar orientation.
The role of ownership structure in integrated reporting policies
Authors: Raimo Nicola , Vitolla Filippo , Marrone Arcangelo , Rubino Michele
Published: March 2020

Integrated reporting (IR) is used to demonstrate a firm's capacity to create value in the short, medium, and long term. It can better represent existing relationships between the company and its stakeholders, with a particular focus on investors. Attention to IR has grown considerably in recent years. However, studies on the determinants of IR quality are still limited. This study aims to bridge this literature gap by being the first study to analyse the role of ownership structure in IR context. To this end, it uses agency theory and is based on a sample of 152 international companies that have adopted IR. The results indicate a positive effect of institutional ownership and a negative effect of ownership concentration, managerial ownership and state ownership on the quality of integrated reports. These results are also consistent with the level of alignment of integrated reports with the  framework. To our knowledge, this is the first study that analyses the role of ownership structure in the IR policies.
Making sense of risk
Authors: Klingele Cecelia
Published: March 2020

Although actuarial risk prediction tools are widely used in the American criminal justice system, the lawyers, judges, and correctional workers who consult these products in making decisions often misunderstand fundamental aspects of how they work and what information they provide. This article suggests that the best way to ensure risk assessment tools are being used in ways that are just and equitable is to ensure that those who use them better understand three key aspects of what information they do – and do not – reveal. Doing so requires clarifying what risk is being predicted, explaining what risk levels signify, and enumerating how risk‐related information is and is not relevant to specific criminal justice decisions.
Hydrogels in the clinic
Authors: Mandal Abhirup , Clegg John R. , Anselmo Aaron C. , Mitragotri Samir
Published: March 2020

Injectable hydrogels are one of the most widely investigated and versatile technologies for drug delivery and tissue engineering applications. Hydrogels’ versatility arises from their tunable structure, which has been enabled by considerable advances in fields such as materials engineering, polymer science, and chemistry. Advances in these fields continue to lead to invention of new polymers, new approaches to crosslink polymers, new strategies to fabricate hydrogels, and new applications arising from hydrogels for improving healthcare. Various hydrogel technologies have received regulatory approval for healthcare applications ranging from cancer treatment to aesthetic corrections to spinal fusion. Beyond these applications, hydrogels are being studied in clinical settings for tissue regeneration, incontinence, and other applications. Here, we analyze the current clinical landscape of injectable hydrogel technologies, including hydrogels that have been clinically approved or are currently being investigated in clinical settings. We summarize our analysis to highlight key clinical areas that hydrogels have found sustained success in and further discuss challenges that may limit their future clinical translation.
Tailoring the Voltage Gap of Organic Battery Materials Based on a Multi‐Electron Redox Chemistry
Authors: Zhang Fei , Cheng Yajuan , Niu Zhihui , Ye Jing , Dai Gaole , Zhang Xiaohong , Zhao Yu
Published: March 2020

Redox‐active organics based on a multi‐electron mechanism are of great interest in battery electrode materials as they are capable of delivering high capacity per molecular weight. However, most of such organics shows huge voltage gap that is inherited from their stepwise redox reactions occurring in the same conjugated redox moiety. This study focuses on the voltage tailoring of polymeric dihydrophenazine derivative, which shows high specific capacity as a cathode electrode material and decent cycling stability, but suffers huge voltage gap of ca. 0.8 V. We demonstrate a strategy to modify the voltage gap of dihydrophenazine derivatives through the incorporation of functional groups with different electron affinity near the redox moiety. The as‐designed dihydrophenazine derivatives are further copolymerized to yield a polymeric material with significantly smoothened charge‐discharge profiles and good capacity retention. We further demonstrate through theoretical calculation based on density‐functional theory that the substitute site and types of functional groups are of great importance in voltage tailoring as well as structural stability of the dihydrophenazine derivatives.
Metal‐Free, N‐Iodosuccinimide‐Induced Regioselective Iodophosphoryloxylation of Alkenes with P(O)−OH Bonds
Authors: Xiong Biquan , Xu Shipan , Zhu Yu , Yao Lei , Zhou Congshan , Liu Yu , Tang Ke‐Wen , Wong Wai‐Yeung
Published: March 2020

A simple and efficient method for the regioselective iodophosphoryloxylation of alkenes with P(O)−OH bonds has been established by using NIS (N‐iodosuccinimide) as the iodination reagent under transition‐metal‐free conditions. The present protocol is compatible with different functional groups, and suitable for various alkenes and P(O)−OH compounds. A variety of functionalized β‐iodo‐1‐ethyl phosphinic/phosphoric acid esters are obtained in good to excellent yields, which could be further transformed to diversified building blocks for the synthesis of bioactive compounds, pharmaceuticals and functional materials.
Towards Atomically Precise Supported Catalysts from Monolayer‐Protected Clusters: The Critical Role of the Support
Authors: Longo Alessandro , de Boed Ewoud J. J. , Mammen Nisha , van der Linden Marte , Honkala Karoliina , Häkkinen Hannu , de Jongh Petra E. , Donoeva Baira
Published: March 2020

Controlling the size and uniformity of metal clusters with atomic precision is essential for fine‐tuning their catalytic properties, however for clusters deposited on supports, such control is challenging. Here, by combining X‐ray absorption spectroscopy and density functional theory calculations, it is shown that supports play a crucial role in the evolution of monolayer‐protected clusters into catalysts. Based on the acidic nature of the support, cluster‐support interactions lead either to fragmentation of the cluster into isolated Au–ligand species or ligand‐free metallic Au0 clusters. On Lewis acidic supports that bind metals strongly, the latter transformation occurs while preserving the original size of the metal cluster, as demonstrated for various Aun sizes. These findings underline the role of the support in the design of supported catalysts and represent an important step toward the synthesis of atomically precise supported nanomaterials with tailored physico‐chemical properties.
Multi‐Color Fluorescent Carbon Dots: Graphitized sp2 Conjugated Domains and Surface State Energy Level Co‐Modulate Band Gap Rather Than Size Effects
Authors: Wei Siqi , Yin Xinghang , Li Haoyi , Du Xiaoyu , Zhang Limei , Yang Qiang , Yang Rui
Published: March 2020

Four types of carbon dots (CDs) with various color (blue, green, yellow, and red) emissions have been synthesized under solvent‐free conditions from citric acid and different nitrogen sources (DMF, urea, ethanamide, and formamide). By detailed characterization and comparison, it is confirmed that the graphitized sp2 conjugated domain and surface functional groups such as C−O and C=N play synergetic roles in adjusting the fluorescence properties. Notably, the size effect is not the dominant mechanism to achieve multi‐color fluorescence emissions in this work. The structural configuration of the carbon dots further influences the energy band structure, as demonstrated in simplified energy level diagrams. An absorption peak at approximately 560 nm appears in the visible light region for red‐emitting CDs, assigned to an n→π* transition of the aromatic structure, thus introducing a new surface state energy level, resulting in a reduction in the energy of electron transition and the expansion into the visible region of the UV/Vis spectrum. Taking advantage of the diverse absorption and emission properties, different CDs/TiO2 binary composites are obtained for photocatalytic degradation of organic dyes, and it is found that the absorption range in terms of visible light and the band gap of the carbon dots make a difference to the photocatalytic performance of the composites.
Understanding the 1,3‐Dipolar Cycloadditions of Allenes
Authors: Yu Song , Vermeeren Pascal , van Dommelen Kevin , Bickelhaupt F. Matthias , Hamlin Trevor A.
Published: March 2020

We have quantum chemically studied the reactivity, site‐, and regioselectivity of the 1,3‐dipolar cycloaddition between methyl azide and various allenes, including the archetypal allene propadiene, heteroallenes, and cyclic allenes, by using density functional theory (DFT). The 1,3‐dipolar cycloaddition reactivity of linear (hetero)allenes decreases as the number of heteroatoms in the allene increases, and formation of the 1,5‐adduct is, in all cases, favored over the 1,4‐adduct. Both effects find their origin in the strength of the primary orbital interactions. The cycloaddition reactivity of cyclic allenes was also investigated, and the increased predistortion of allenes, that results upon cyclization, leads to systematically lower activation barriers not due to the expected variations in the strain energy, but instead from the differences in the interaction energy. The geometric predistortion of cyclic allenes enhances the reactivity compared to linear allenes through a unique mechanism that involves a smaller HOMO–LUMO gap, which manifests as more stabilizing orbital interactions.
Structure and Bonding in a Diamond‐Shaped Tin Cluster Possessing a cyclo‐Sn4 Core
Authors: Handford Rex C. , Wheeler T. Alex , Tilley T. Don
Published: March 2020

A tetrameric cluster composed entirely of (aryl)Sn units, [DMPSn]4 (DMP=2,6‐dimesitylphenyl), has been prepared by reduction of [DMPSnCl]2 with a variety of reductants. This cluster was characterized in solution by multinuclear NMR spectroscopies, as well as in the solid‐state by single crystal X‐ray diffraction analysis. This species is stereochemically nonrigid in solution and possesses a cyclo‐Sn4 core whose DMP substituents are equivalent at higher temperatures. The solid‐state molecular structure is remarkably unsymmetrical and possesses a nearly planar cyclo‐Sn4 core. The DMP substituents are arranged such that three are approximately coplanar, while one is nearly perpendicular to the cyclo‐Sn4 core. Density functional theory calculations for a [PhSn]4 model system show that this distorted geometry about the cyclo‐Sn4 core maximizes σ‐bonding between the Sn centers in a manner reminiscent of trans‐bent bonding in the heavy group 14 analogues of alkenes and alkynes.
Naphthalimide Dyes with Orthogonal Functional Groups for “Click” Chemistry: Attachment to Solid Supports and Applications in Drug Allergy Diagnosis
Authors: Ruiz‐Sanchez Antonio J. , Collado Daniel , Mayorga Cristobalina , Torres Maria J. , Perez‐Inestrosa Ezequiel
Published: March 2020

The preparation and characterization of new functional materials for sensing have an important role in clinical diagnosis. Monitoring the surface functionalization of functional material is crucial because the final sensing properties are affected by how the (bio)molecules are immobilized on the surface of solid supports. Here, a new approach for the preparation of functional materials for biomedical diagnosis was developed. This method employs a fluorescent dye comprising 4‐amino‐1,8‐naphthalimide with two orthogonal functional groups suitable for click chemistry. The orthogonal reactivity of these groups allows the sequential functionalization of the fluorophore, firstly with (bio)molecules, and then binding of the (bio)molecule‐naphthalimide macrostructure onto the surface of a solid support. The fluorescent properties confirm the immobilization of the (bio)molecule on the surface of the solid support, without requiring other indirect methods to verify the immobilization. These functional materials were tested successfully with sera of patients, thus proving their potential application for allergic drug diagnosis.
Chlamydia trachomatis in the gingival sulcus and pharynx in patients of Northeast Mexico
Authors: Coronado‐Cerda Erika E. , Ancer‐Rodríguez Jesus , Montemayor‐Martínez Raul , Canabal‐Hermida Fabrizio , Gallegos‐Avila Guadalupe , De la Garza‐Ramos Myriam A.
Published: March 2020

Background

The oral microenvironment provides the conditions for the establishment of microorganisms not usually considered residents of the normal oral microbiota. Sexually transmitted microorganisms such as Chlamydia trachomatis can adhere to any mucosal surface and ascend to reach appropriate locations to survive and develop symptomatic infections.

Materials and methods

To determine the presence of C. trachomatis, direct immunofluorescence of this microorganism was carried out in 76 randomly selected patients attending a periodontal clinic during a period of 1 year. Samples from the gingival sulcus and the pharynx were collected for detection of C. trachomatis. Patients who attended the periodontal clinic were divided into two groups: those without periodontitis and those with periodontitis. For the purpose of performing other statistical analyses, all patients were also divided by gender and age.

Results

From the total of 76 patients, in the group without periodontitis, 61% were positive for C. trachomatis in the gingival sulcus and 63.4% in the pharynx; in the periodontitis group, 45.7% were positive in the sulcus and 40% in the pharynx. When we compared patients by gender or age, no statistical difference was found.

Conclusions

The prevalence of C. trachomatis in this group was 53.9% in the gingival sulcus and pharynx of the studied patients.
Characterization of post‐haustorial resistance to sunflower broomrape
Authors: Martín‐Sanz Alberto , Pérez‐Vich Begoña , Rueda Sandra , Fernández‐Martínez José M. , Velasco Leonardo
Published: March 2020

The development of durable resistance to broomrape (Orobanche cumana Wallr.) in sunflower (Helianthus annuus L.) requires detailed characterization of the genetic and physiological bases of resistance. The objective of the present study was to map the resistance gene accurately, and to characterize the mechanism of resistance to broomrape observed in a sunflower inbred line (PHSC1102). PHSC1102, which was consistently resistant against race F and race G populations of broomrape, was crossed with PHSC1201, which was susceptible to races F and G. A mapping population of 150 F2 genotypes was phenotyped by evaluating F2:3 families for resistance to broomrape races FGV and GTK. The use of single nucleotide polymorphism (SNP) markers mapped the OrSII gene to Linkage Group 4 (LG4) of the sunflower genome. Mini‐rhizotron and histological studies of the resistant line revealed that the attachment of broomrape to host roots was similar in both the resistant and susceptible lines and that the resistance was observed at a late stage (i.e., after tubercle development). Interestingly, the resistance of the PHSC1102 line was associated with the production of phenolic compounds, which were hypothesized to restrict the parasite's growth. This research provides novel and valuable information about the host–parasite interactions between sunflower and broomrape.
Exploring the QTL–allele constitution of main stem node number and its differentiation among maturity groups in a Northeast China soybean population
Authors: Fu Mengmeng , Wang Yanping , Ren Haixiang , Du Weiguang , Yang Xingyong , Wang Deliang , Cheng Yanxi , Zhao Jinming , Gai Junyi
Published: March 2020

Northeast China (NEC) is a major soybean [Glycine max (L.) Merr.] production region in China, where the germplasm of American soybeans are mainly from. The main stem node number (MSN) is a trait related to plant type and yield potential. With the soybeans expanded to higher latitudes in NEC, earlier maturity groups (MG 0, MG 00, and MG 000) formed based on MG I + MG II (MG I+II), and correspondingly the MSN decreased. To explore the MSN quantitative trait locus (QTL)–allele constitution, 306 accessions from NEC were studied using the restricted two‐stage multilocus genome‐wide association study (RTM‐GWAS) procedure. In total, 76 MSN QTLs and 183 alleles were identified, with their genetic contribution about 0.04–9.83% per locus for a total of 65.63% for all loci. With the MSN reduction from MG I+II to MG 0, MG 00, and MG 000 (17.89 to 13.11), the changed alleles accounted for 28.42% of all alleles (6.56% for new allele emergence plus 21.86% for old allele exclusion), whereas the major part of the alleles were those inherited from MG I+II (71.58%). Thus in the evolution of MSN in the NEC soybean population, inheritance is the first genetic motivation, exclusion and selection (positive allele exclusion, 65.00%) is the second, emergence and mutation (negative allele emergence, 95.67%) is the third, and recombination among retained alleles is the fourth. A potential of 2–5 MSN improvement keeping the MG earliness was predicted, and 49 candidate genes were identified.
Family × environment interaction for sugarcane yield and its components in South Africa
Authors: Mbuma Ntombokulunga W. , Zhou Marvellous M. , van der Merwe Rouxlene
Published: March 2020

In sugarcane (Saccharum spp. hybrids) breeding, knowledge of progeny performance and adaptability increases crossing and selection efficiency. Family evaluation across environments uses progeny data to determine family genetic values and family × environment interactions. The objectives were to determine family × environment breeding parameters, family values across locations, and contribution of yield components to cane yield of families in different environments. Data were collected from the plant, first ratoon, and second ratoon crops of 44 families made from 18 female and 18 male parents and planted in the Midlands (24 mo harvest), coastal (12–18 mo), and irrigated (12 mo) environments. Cane yield was estimated from stalk number, stalk height, and stalk diameter, measured from the first 20 plants per family plot. Significant (P < .01) family variance for cane yield traits indicated genetic variability among the families. Significant (P < .01) family × location variance for cane yield, stalk number, and diameter indicated that the magnitude of genetic variability among families was influenced by location. The nonsignificant (P > .05) family × crop year and family × location × crop year variances indicated similar genetic variability across crop years. Therefore, testing families in multiple locations was more important than across crop years. Best linear unbiased predictor estimates showed that families TT1051, UU0332, and UU0312 had significantly higher cane yield across locations and, therefore, were broadly adapted. VV0701 (irrigated), VV0390 (Midlands), and UU0198 (Midlands) produced greater cane yield and showed location‐specific adaptability. The irrigated, coastal, and Midlands populations showed higher specific adaptability for cane yield and stalk height.
Multitrait differential response in a diverse potato panel under contrasting water regimes
Authors: Tagliotti Martin E. , Bedogni María C. , Cendoya María G. , Ortego Jaime , Huarte Marcelo A.
Published: March 2020

Water stress is the most significant environmental stress in agriculture worldwide. Potato (Solanum tuberosum L.) is a drought‐susceptible crop. Water stress tolerance is a complex trait of increasing importance in potato. The objective of this work was to evaluate the differential response strategies associated with water stress tolerance in a highly diverse potato panel. Multienvironment trials were assessed, both in field and in glasshouse with contrasting water regimes. The yield, dry matter, and frying ability were measured in the field assays, whereas proline concentration (PrC), relative water content (RWC), and water consumption (WC) were measured in the glasshouse assays. A mixed linear model and ANOVA were performed. The best linear unbiased predictors (BLUPs) of every genotype for each measured variable were estimated. Pearson correlation coefficient (r) and principal component analysis (PCA) assessed the association among traits. The genotypes were ranked by their BLUPs values. The high diversity potato panel showed variability both in the response to water stress and within each water regime. In general, Solanum tuberosum spp. andigena genotypes were associated with the lowest PrC and higher yield, WC, and RWC. By using BLUPs, a panel of genotypes with good performance under water deficit was defined. This paper provides knowledge useful to design breeding strategies to water stress tolerance and new physiological research lines. The utilization of the elite genotypes identified in this study as progenitors constitute a starting point for breeding programs oriented to develop water‐stress‐tolerant varieties.
A Family of Water‐Immiscible, Dipolar Aprotic, Diamide Solvents from Succinic Acid
Authors: Byrne Fergal P. , Nussbaumer Clara M. , Savin Elise J. , Milescu Roxana A. , McElroy Con R. , Clark James H. , van Vugt‐Lussenburg Barbara M. A. , van der Burg Bart , Meima Marie Y. , Buist Harrie E. , Kroese E. Dinant , Hunt Andrew J. , Farmer Thomas J.
Published: March 2020

Three dipolar aprotic solvents were designed to possess high dipolarity and low toxicity: N,N,N′,N′‐tetrabutylsuccindiamide (TBSA), N,N′‐diethyl‐N,N′‐dibutylsuccindiamide (EBSA), and N,N′‐dimethyl‐N,N′‐dibutylsuccindiamide (MBSA). They were synthesized catalytically by using a K60 silica catalyst in a solventless system. Their water immiscibility stands out as an unusual and useful property for dipolar aprotic solvents. They were tested in a model Heck reaction, metal–organic framework syntheses, and a selection of polymer solubility experiments in which their performances were found to be comparable to traditional solvents. Furthermore, MBSA was found to be suitable for the production of an industrially relevant membrane from polyethersulfone. An integrated approach involving in silico analysis based on available experimental information, prediction model outcomes and read across data, as well as a panel of in vitro reporter gene assays covering a broad range of toxicological endpoints was used to assess toxicity. These in silico and in vitro tests suggested no alarming indications of toxicity in the new solvents.
Exploiting Radioactive Isotopes: from Pollutant Tracking to Solid State Studies Using a Combined Ab Initio and PAC Approach
Authors: Amorim Carlos O. , Gonçalves João N. , Amaral Vítor S.
Published: March 2020

In this review we present examples of using radioactive isotopes as probes to study functional materials of fundamental and applied interest presenting colossal magnetoresistance, multiferroic effects, and magnetostructural coupling. Most of the works exploit the hyperfine properties, Electric Field Gradient (EFG) and Hyperfine Magnetic Field (HMF), of these probes through Perturbed Angular Correlation (PAC) spectroscopy. The measurements were complemented with density functional theory calculations to model the relevant properties and correlate the EFG with the electric polarization. We also present a methodological and nuclear physics related contribution consisting on the characterization of a new short‐lived isotope adequate for PAC studies. Finally, an ultra‐sensitive method to quantify the uptake of Hg by nano sorbents based on the tracking the radioactive isotopes of mercury is also reviewed. These works showcase the diversity of our research with radioisotopes, at the interface of different science fields, with combination of different methodologies and different motivations such as fundamental materials physics and chemistry or environmental concerns.
0D to 3D Coordination Assemblies Engineered on Silver(I) Salts and 2‐(Alkylsulfanyl)azine Ligands: Crystal Structures, Dual Luminescence, and Cytotoxic Activity
Authors: Rogovoy Maxim I. , Frolova Tatiana S. , Samsonenko Denis G. , Berezin Alexey S. , Bagryanskaya Irina Yu. , Nedolya Nina A. , Tarasova Olga A. , Fedin Vladimir P. , Artem'ev Alexander V.
Published: March 2020

The potential of 2‐(alkylsulfanyl)azine ligands for crystal engineering of functional Ag(I) complexes has been firstly demonstrated. The reaction of AgNO3, AgClO4 and AgOTf with 2‐(alkylsulfanyl)pyridines, ‐pyrimidines, and ‐quinolines gives a series of new Ag(I) compounds that range from mono‐ and dinuclear complexes to chain (1D), layered (2D) and framework (3D) coordination polymers (CPs). 2‐(Alkylsulfanyl)pyridines and ‐pyrimidines, depending on the reaction conditions, are assembled either into molecular complexes or CPs, while 2‐(alkylsulfanyl)quinolines afford dinuclear complexes exclusively. The most of compounds engineered feature site‐specific interactions such as Ag···Ag, Ag···O, and Ag···S ones. The 2‐(methylsulfanyl)quinoline (2‐MeSQn) complex, [Ag2(2‐MeSQn)2(NO3)2], displays room temperature intraligand (IL) phosphorescence, while the 2‐(methylsulfanyl)pyridine‐derived CPs emit dual luminescence expressed by IL fluorescence and phosphorescence. Moreover, cytotoxic activity of the compounds synthesized has been evaluated against hTERT lung fibroblasts, HeLa, MCF7, HepG2 and A549 cancer cells.
Effect of Mie Scattering on Thermochromic Performance of Branched VO2 Prepared by One‐Step Hydrothermal Method
Authors: Wang Xi , Li Ming , Wang Qingsheng , Zhang Jikui , Shi Jiaming , Lu Yuan , Li Guanghai
Published: March 2020

In this work, gram‐scale branched‐VO2 (B‐VO2) was synthesized via a mild one‐step hydrothermal route, and the corresponding phase transition, optical and electrical performances of B‐VO2 were investigated. The differential scanning calorimeter (DSC) results revealed the defect mediated phase transition behavior of B‐VO2. The optical studies demonstrated an analogous negative thermochromic performance of B‐VO2, which was ascribed to the intense Mie scattering effect. While, ball milling treatment was an effective way to restore the regular thermochromic property, and the ball‐milled VO2 (BM‐VO2) displayed a 6.3 % increasement of the solar modulation ability. The BM‐VO2 films on flexible PET and PI substrates demonstrated both energy‐saving and UV‐shielding functions. The temperature dependent resistivity displayed about two orders of magnitude change during the phase transition of VO2.
Copper‐Promoted Formation of Vinylsiloxanes
Authors: Białoń Marietta , Dziuk Błażej , Olijnyk Volodymyr
Published: March 2020

The metathesis reactions of chlorovinylsilanes with copper(I) oxide are reported. The process is catalyzed by HCl which can be in situ generated via hydrolysis of chlorosilanes by traces of water present in the system. An appearance of olefin/CuCl π‐intermediates can provide a stereoselectivity of the process and alter the pathway of siloxanes formation employing Cu2O as the source of oxygen. It was also shown that acetonitrile may be available as a solvent for construction of the systems with large preparative capabilities, including those based on the use atmospheric oxygen in siloxane synthesis.
Perfluoropyridine as an Efficient, Tunable Scaffold for Bis(pyrazol‐1‐yl)pyridine Copper Complexes
Authors: Peloquin Andrew J. , Houck Matthew B. , McMillen Colin D. , Iacono Scott T. , Pennington William T.
Published: March 2020

This report details the syntheses of five new 2,6‐bis(pyrazol‐1‐yl)pyridine ligands carried out by a unique strategy of utilizing pentafluoropyridine for the pyridine core. Formation of each ligand is accomplished under mild conditions utilizing carbonate bases. Each ligand reacts readily with copper(II) triflate to form the corresponding salt in high yield. Ligands and complexes were characterized by a combination of multi‐nuclear NMR, FTIR, UV/Vis, and single‐crystal X‐ray diffraction. Copper(II) triflate complexes demonstrating additional coordination modes of this multi‐pyrazole ligand system were also obtained. Despite the electron withdrawing nature of fluorine, the coordination parameters of the new complexes are comparable to previous pyrazole‐based complexes. This synthetic methodology provides efficient entry to a previously difficult to access ligand system.
Electrochemical Evaluation of Pollutants in the Environment: Interaction Between the Metal Ions Zn(II) and Cu(II) with the Fungicide Thiram in Billings Dam
Authors: Alves Sá da Silva Vitor , da Silva Santos Aymara , Ferreira Tiago Luiz , Codognoto Lúcia , Agostini Valle Eliana Maíra
Published: March 2020

Pesticides are organic molecules used in the control of various pests in different crops. These molecules show functional groups that can interact with metal ions, forming new species with different properties. These new compounds have been attracting attention because they can become a new environmental problem. In this work the interaction of copper and zinc metal ions with Thiram pesticide was studied using electrochemical techniques. Studies in ultrapure water showed the formation of Zn−Thiram complex with reduction potential at −1.330 V; Cu−Thiram complex showed a cathodic peak at 0.020 V. Thiram causes a different effect on the two metal ions studied. It was observed that the ligand stabilizes more the Cu(II) than Zn(II). Both systems proved to be quasi‐reversible, controlled by the adsorption of the species on the electrode surface. The formation constants of the complexes were calculated to be 2.1×105 for Zn−Thiram and 1.5×1019 for Cu−Thiram. In the samples from Billings dam, the Zn‐complex showed reduction potential at −1.403 V; Cu‐complex exhibited a reduction peak at 0.012 V. Although there are interferers in river waters, the interaction of these metals with the pesticide showed high affinity, being possible to detect them in natural samples. The Cu(II) complex showed to be more stable in natural matrices when compared to the Zn(II) complex. The sensitivity for thiram electroanalytical determination decreases in the presence of Zn(II) and Cu(II).