bluuebunny/crossref_metadata_2025 huggingface dataset:
Dual binding mode of antithyroid drug methimazole to mammalian heme peroxidases – structural determination of the lactoperoxidase–methimazole complex at 1.97 Å resolution
Authors: Singh Rashmi Prabha , Singh Avinash , Sirohi Harsh Vardhan , Singh Amit Kumar , Kaur Punit , Sharma Sujata , Singh Tej P.
Published: March 2016

Lactoperoxidase (LPO, EC 1.11.1.7) is a member of the mammalian heme peroxidase family which also includes thyroid peroxidase (TPO). These two enzymes have a sequence homology of 76%. The structure of LPO is known but not that of TPO. In order to determine the mode of binding of antithyroid drugs to thyroid peroxidase, we have determined the crystal structure of LPO complexed with an antithyroid drug, methimazole (MMZ) at 1.97 Å resolution. LPO was isolated from caprine colostrum, purified to homogeneity and crystallized with 20% poly(ethylene glycol)‐3350. Crystals of LPO were soaked in a reservoir solution containing MMZ. The structure determination showed the presence of two crystallographically independent molecules in the asymmetric unit. Both molecules contained one molecule of MMZ, but with different orientations. MMZ was held tightly between the heme moiety on one side and the hydrophobic parts of the side chains of Arg255, Glu258, and Leu262 on the opposite side. The back of the cleft contained the side chains of Gln105 and His109 which also interacted with MMZ. In both orientations, MMZ had identical buried areas and formed a similar number of interactions. It appears that the molecules of MMZ can enter the substrate‐binding channel of LPO in two opposite orientations. But once they reach the distal heme pocket, their orientations are frozen due to equally tight packing of MMZ in both orientations. This is a novel example of an inhibitor binding to an enzyme with two orientations at the same site with nearly equal occupancies.
Breaking the link between provocation and aggression: The role of mitigating information
Authors: Barlett Christopher , Witkower Zachary , Mancini Colin , Saleem Muniba
Published: March 2016

In two experimental studies, we examine the extent to which strong or weak mitigating information after a provocation alters aggressive responding. In Study 1, we randomly assigned 215 (108 female) college‐aged participants to a strong or weak provocation by having a research assistant talk to the participant about failing a task in a harsh or confused tone. This was followed by a second research assistant giving a strong or weak excuse to the participant regarding the first research assistant's behavior. Then, aggressive behavior was assessed using a researcher rating task. In Study 2, 63 (25 female) college‐aged participants interacted with a confederate on the CRT. All participants were strongly provoked by receiving strong noise blasts. After five CRT trials, the confederate delivered weak or strong mitigating information to the participant regarding the noises blasts. The results indicated that: (i) strong provocations are more likely to increase aggression than weak provocations; (ii) strong mitigating information is more likely to decrease aggression than weak mitigating information; and (iii) the varying strength of mitigating information is important in situations involving weak, but not strong provocations: strong mitigating information is more likely than weak mitigating information reduce aggression when provocation is strong, but not when provocation is weak. We discuss the importance of mitigating information in decreasing aggressive behavior and the conditions in which mitigating information is especially likely to be effective. Aggr. Behav. 42:555–562, 2016. © 2016 Wiley Periodicals, Inc.
Exploring the Use of Experience Sampling to Assess Episodic Thought
Authors: Busby Grant Janie , Walsh Erin
Published: March 2016

Mental time travel is the ability to mentally relive events in one's own past (episodic recall) and pre‐live potential personal future events (episodic foresight). Recent research has used experience sampling to reveal when and how often we think about the past and future in everyday life; however, it remains unclear how much of thought is episodic, involving the sense of self that underpins mental time travel. In this study, we investigate the use of experience sampling to assess the frequency of episodic past and future thought in everyday life. Participants (n = 214) were exposed to 20 short message service prompts over 1 or 2 days. Half of thoughts were sited in the present; of the remainder, future‐oriented thoughts were more frequent than past‐oriented thoughts. Participants reported 20% of thoughts as episodic. This study suggests that experience sampling methodology can provide a means of assessing episodic thought during everyday activities.Copyright © 2016 John Wiley & Sons, Ltd.
Parametric Notations: The Birth of the Non‐Standard
Authors: Carpo Mario
Published: March 2016

The use of scripted parameters that define objects in architecture is generally regarded as a recent phenomenon, associated with digital design. Mario Carpo, Reyner Banham Professor of Architectural Theory and History at the Bartlett School of Architecture, University College London (UCL), describes how parametric notations are part of an enduring architectural lineage that has its roots in the theses of classical antiquity and the Middle Ages, previous to printing, when the only means of disseminating the proportions and combining of elements was to describe them, writing them out by hand without the aid of illustration.
Antoni Gaudí and Frei Otto: Essential Precursors to the Parametricism Manifesto
Authors: Burry Mark
Published: March 2016

As Senior Architect to the Basilica of the Sagrada Família in Barcelona, Mark Burry has been ‘thinking parametrically’ for almost his entire career. Here he describes how his longstanding role overseeing the completion of Antoni Gaudí's masterpiece has afforded unique insights into the work of a great geometer and parametric thinker. Burry places the contribution of Gaudí alongside that of Frei Otto – the other eminent 20th‐century Proto‐Parametricist.
Behavioural Complexity: Constructing Frameworks for Human‐Machine Ecologies
Authors: Spyropoulos Theodore
Published: March 2016

Founded by Patrik Schumacher and Brett Steele in 1997, the Architectural Association Design Research Laboratory (AADRL) Master's programme,based at the AA in London, provides an important research base for Parametricism. The current Director of AADRL, Theodore Spyropoulos, continues to push the boundaries of advanced computing and machine intelligence. Here he describes the work that he has undertaken at the AA and through his practice Minimaforms into adaptive ecologies that employ responsive machine learning to enable spatial transformations.
Upgrading Computational Design
Authors: Bhooshan Shajay
Published: March 2016

Shajay Bhooshan heads up the computation and design ZHACODE group at Zaha Hadid Architects (ZHA) and is a course master at the Architectural Association Design Research Laboratory (AADRL). Here he argues that Parametricism 2.0 has a vital role to play in the progressing of computational design. Assimilating the exploratory developments of the last 15 years, he asserts how the next phase of Parametricism will enable a further consolidation and evolution of digital practices.
Behavioural Production: Autonomous Swarm‐Constructed Architecture
Authors: Stuart‐Smith Robert
Published: March 2016

Until now, parametric processes have largely been confined to the architectural and engineering phases of a building's design. What possibilities, however, do robotics and artificial intelligence programming open up for extending Parametricism's influence into the construction phase? Robert Stuart‐Smith, a course master at the Architectural Association Design Research Laboratory (AADRL), explores how architecture might adopt autonomous swarm‐construction techniques. He describes the research that he has carried out with colleagues and students employing flying multicopters or unmanned aerial vehicles (UAVs) to design and additively manufacture 3D‐printed buildings onsite.
The Art of the Prototypical
Authors: Fornes Mark
Published: March 2016

Poised between design research and full‐scale realisation, prototypes in architecture provide a significant stepping stone for innovation. Through his New York‐based studio THEVERYMANY, Mark Fornes explores the possibilities of coding and computer prototcols for design and fabrication through art installations and architectural structures. As prototypical projects, they are each defined by a single architectural concern, like a structure, enclosure or porosity; the intention being to realise the structure as a pleasurable spatial experience with potential for scalability.
Parametricism's Structural Congeniality
Authors: Block Philippe
Published: March 2016

The Block Research Group (BRG) at the Institute of Technology in Architecture, ETH Zurich, led by Philippe Block and Tom Van Mele, focuses on research in equilibrium analysis, computational form‐finding and the fabrication of curved‐surface structures. Here, Philippe Block describes how Parametricism's preoccupation with expressive surface structures enables architecture ‘to learn from the past’ and draw on the rich seam of historical knowledge that has informed the complex curved structures of the Gothic cathedral builders and modern masters.
Computational Material Culture
Authors: Menges Achim
Published: March 2016

Computation offers considerable possibilities for architecture, going well beyond the conventional sphere of design that focuses on the generation of complex geometries. Achim Menges, a regular contributor and guest‐editor to 2, and Founding Director of the Institute for Computational Design (ICD) at the University of Stuttgart, is renowned for his pioneering approach to computation and materials. He describes how computation is enabling a convergence of the processes of form generation and materialisation, hailing in new areas of architectural speculation and experimentation, as demonstrated by the ICD/ITKE pavilions illustrated here.
Parametric Regionalism
Authors: Yuan Philip
Published: March 2016

Philip Yuan, Founding Director of Shanghai‐based firm Archi‐Union Architects, applies parametric techniques to his design and research in China. Here he explains how Parametricism can provide a highly adaptive and open approach to architectural knowledge and spatial organisation, accommodating regional variations in culture and environment, through an emphasis on local climate, materials and craft traditions.
‘Super‐Natural’: Parametricism in Product Design
Authors: Lovegrove Ross
Published: March 2016

As a stylistic movement, Parametricism has the scope to move beyond the limits of architecture, penetrating adjacent disciplines. Renowned industrial designer Ross Lovegrove, known as ‘Captain Organic’ for his nature‐inspired designs, acknowledges the potential of ‘new codes of creation’ being incubated in architecture schools for product design, accelerating innovation across materials, structures and manufacturing technologies.
Hegemonic Parametricism Delivers a Market‐Based Urban Order
Authors: Schumacher Patrik
Published: March 2016

How might Parametricism be widely adopted at an urban scale? Guest‐Editor Patrik Schumacher argues that Parametricism 2.0 has now matured sufficiently at a technical and stylistic level to engage with the creation of ‘a complex, variegated urban order’. Moreover, he avows that it should be adequately adaptable to respond to the dynamic forces influencing global markets, assuming a prominent position as a mainstream movement.
Efficient and Stable Bifunctional Electrocatalysts Ni/NixMy (M = P, S) for Overall Water Splitting
Authors: Chen Gao‐Feng , Ma Tian Yi , Liu Zhao‐Qing , Li Nan , Su Yu‐Zhi , Davey Kenneth , Qiao Shi‐Zhang
Published: March 2016

Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni8P3 and Ni/Ni9S8 electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni8P3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm−2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO2 and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels.
Hired crop worker injuries on farms in the United States: A comparison of two survey periods from the National Agricultural Workers Survey
Authors: Tonozzi Theresa R. , Layne Larry A.
Published: March 2016

Background

Hired crop workers in the United States are at high risk of occupational injury. Targeted surveillance is important for effective occupational safety efforts.

Methods

The National Agricultural Workers Survey was utilized to collect injury data during the years 1999, 2002–2004 (period I) and 2008–2010 (period II).

Results

The overall injury rate declined between the two periods from 4.3 to 2.9/100 per full‐time week‐based equivalents (FTEWB). Injury rates remained high during both periods for those with greater than 20 years farm experience (3.6 and 3.8/100 FTEWB) and pesticide handling work (4.9 and 5.0/100 FTEWB). Overexertion, contact with objects and equipment, and falls from height were common during both periods. Older workers comprised a greater proportion of injury cases in period II.

Conclusion

Overexertion that leads to sprains/strains, dangerous ladder use, and pesticide use should be targeted as important risk exposures on the farm. Am. J. Ind. Med. 59:408–423, 2016. © Published 2016. This article is a U.S. Government work and is in the public domain in the USA
Occupational fatalities among young workers in the United States: 2001–2012
Authors: Rauscher Kimberly J. , Myers Douglas J.
Published: March 2016

Background

While adolescent workers in the United States (US) are protected by child labor laws, they continue to suffer fatal occupational injuries. This study was designed to provide a comprehensive profile of occupational fatalities among this sub‐population of US workers.

Methods

Using Census of Fatal Occupational Injuries data between 2001 and 2012, we calculated descriptive statistics and rates to examine the magnitude and nature of fatalities among workers under age 18.

Results

During the study period, there were 406 fatalities among young workers which translated into 24,790 years of potential life lost; 12,241 of which were in agriculture alone. Rates declined since 2001 yet Hispanics, foreign‐born workers, males, and those working in agriculture continued to suffer a disproportionate fatality burden.

Conclusions

Efforts to reduce young worker fatalities should focus on male Hispanics, particularly those who are foreign‐born, as well as agricultural workers as these groups have the greatest fatality risks. Am. J. Ind. Med. 59:445–452, 2016. © 2016 Wiley Periodicals, Inc.
Employer reasons for failing to report eligible workers’ compensation claims in the BLS survey of occupational injuries and illnesses
Authors: Rappin Christina L. , Wuellner Sara E. , Bonauto David K.
Published: March 2016

Background

Little research has been done to identify reasons employers fail to report some injuries and illnesses in the Bureau of Labor Statistics Survey of Occupational Injuries and Illnesses (SOII).

Methods

We interviewed the 2012 Washington SOII respondents from establishments that had failed to report one or more eligible workers’ compensation claims in the SOII about their reasons for not reporting specific claims. Qualitative content analysis methods were used to identify themes and patterns in the responses.

Results

Non‐compliance with OSHA recordkeeping or SOII reporting instructions and data entry errors led to unreported claims. Some employers refused to include claims because they did not consider the injury to be work‐related, despite workers’ compensation eligibility. Participant responses brought the SOII eligibility of some claims into question.

Conclusion

Systematic and non‐systematic errors lead to SOII underreporting. Insufficient recordkeeping systems and limited knowledge of reporting requirements are barriers to accurate workplace injury records. Am. J. Ind. Med. 59:343–356, 2016. © 2016 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.
RASA1 somatic mutation and variable expressivity in capillary malformation/arteriovenous malformation (CM/AVM) syndrome
Authors: Macmurdo Colleen F. , Wooderchak‐Donahue Whitney , Bayrak‐Toydemir Pinar , Le Jenny , Wallenstein Matthew B. , Milla Carlos , Teng Joyce M. C. , Bernstein Jonathan A. , Stevenson David A.
Published: March 2016

Germline mutations in RASA1 are associated with capillary malformation‐arteriovenous malformation (CM‐AVM) syndrome. CM‐AVM syndrome is characterized by multi‐focal capillary malformations and arteriovenous malformations. Lymphatic anomalies have been proposed as part of the phenotype. Intrafamilial variability has been reported, suggesting modifiers and somatic events. The objective of the study was to identify somatic RASA1 “second hits” from vascular malformations associated with CM‐AVM syndrome, and describe phenotypic variability. Participants were examined and phenotyped. Genomic DNA was extracted from peripheral blood on all participants. Whole‐exome sequencing was performed on the proband. Using Sanger sequencing, RASA1 exon 8 was PCR‐amplified to track the c.1248T>G, p.Tyr416X germline variant through the family. A skin biopsy of a capillary malformation from the proband's mother was also obtained, and next‐generation sequencing was performed on DNA from the affected tissue. A familial germline heterozygous novel pathogenic RASA1 variant, c.1248T>G (p.Tyr416X), was identified in the proband and her mother. The proband had capillary malformations, chylothorax, lymphedema, and overgrowth, while her affected mother had only isolated capillary malformations. Sequence analysis of DNA extracted from a skin biopsy of a capillary malformation of the affected mother showed a second RASA1 somatic mutation (c.2245C>T, p.Arg749X). These results and the extreme variable expressivity support the hypothesis that somatic “second hits” are required for the development of vascular anomalies associated with CM‐AVM syndrome. In addition, the phenotypes of the affected individuals further clarify that lymphatic manifestations are also part of the phenotypic spectrum of RASA1‐related disorders. © 2016 Wiley Periodicals, Inc.
15q13.3 duplication in two patients with childhood‐onset schizophrenia
Authors: Zhou Dale , Gochman Peter , Broadnax Diane D. , Rapoport Judith L. , Ahn Kwangmi
Published: March 2016

We report two cases of paternally inherited 15q13.3 duplications in carriers diagnosed with childhood‐onset schizophrenia (COS), a rare neurodevelopmental disorder of proposed polygenic origin with onset in children before age 13. This study documents that the 15q13.3 deletion and duplication exhibit pathogenicity for COS, with both copy number variants (CNVs) sharing a disrupted CHRNA7 gene. CHRNA7 encodes the neuronal alpha7 nicotinic acetylcholine receptor (α7nAChR) and is a candidate gene that has been suggested as a pathophysiological process mediating adult‐onset schizophrenia (AOS) and other neurodevelopmental disorders. These results support the incomplete penetrance and variable expressivity of this CNV and represent the first report of 15q13.3 duplication carriers exhibiting COS. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics published by Wiley Periodicals, Inc.
Defining appropriateness criteria for endoscopic sinus surgery during management of uncomplicated adult chronic rhinosinusitis: a RAND/UCLA appropriateness study
Authors: Rudmik Luke , Soler Zachary M. , Hopkins Claire , Schlosser Rodney J. , Peters Anju , White Andrew A. , Orlandi Richard R. , Fokkens Wytske J. , Douglas Richard , Smith Timothy L.
Published: March 2016

Background

Appropriate indications for endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) are currently poorly defined. The lack of clear surgical indications for ESS likely contributes to the large geographic variation in surgical rates and contributes to reduced quality of care. The objective of this study was to define appropriateness criteria for ESS during management of adult patients with uncomplicated CRS.

Methods

The RAND/UCLA appropriateness methodology was performed. An international, multidisciplinary panel of 10 experts in CRS was formed and completed 2 rounds of a modified Delphi ranking process along with a face‐to‐face meeting.

Results

A total of 624 clinical scenarios were ranked, 312 scenarios each for CRS with and CRS without nasal polyps. For adult patients with uncomplicated CRS with nasal polyps, ESS can be appropriately offered when the CT Lund‐Mackay score is ≥ 1 and there has been a minimum trial of a topical intranasal corticosteroid plus a short‐course of systemic corticosteroid with a post‐treatment total SNOT‐22 score ≥ 20. For adult patients with uncomplicated CRS without nasal polyps, ESS can be appropriately offered when the CT Lund‐Mackay score is ≥ 1 and there has been a minimum trial of a topical intranasal corticosteroid plus either a short‐course of a broad spectrum/culture‐directed systemic antibiotic or the use of a prolonged course of systemic low‐dose anti‐inflammatory antibiotic with a post‐treatment total SNOT‐22 score ≥ 20.

Conclusion

This study has developed and reported of list of appropriateness criteria to offer ESS as a treatment “option” during management of uncomplicated adult CRS. The extent or technique of ESS was not addressed in this study and will depend on surgeon and patient factors. Furthermore, these criteria are the minimal threshold to make ESS a treatment “option” and do not imply that all patients meeting these criteria require surgery. The decision to perform ESS should be made after an informed patient makes a preference‐sensitive decision to proceed with surgery. Applying these appropriateness criteria for ESS may optimize patient selection, reduce the incidence of unwarranted surgery, and assist clinicians in providing high‐quality, patient‐centered care to patients with CRS
Ventricular septal perforation after blunt chest trauma due to blows from a fist
Authors: Muratsu Arisa , Muroya Takashi , Onoe Atsunori , Nakamura Fumiko , Wada Daiki , Nakajima Mari , Iwamura Hiromu , Kishimoto Masanobu , Yui Rintaro , Sakuramoto Kazuhito , Hayakawa Koichi , Saito Fukuki , Nakamori Yasushi , Kuwagata Yasuyuki
Published: March 2016

Case

A 40‐year‐old man received fist blows to his chest and abdomen. He presented with external jugular vein distention and facial congestion. Chest X‐ray showed bilateral pulmonary congestion. A Levine V/VI holosystolic murmur was audible. Echocardiography showed left‐to‐right shunt flow across the perimembranous region of the ventricular septum. The diameter of the hole was approximately 13 mm. We diagnosed ventricular septal perforation, started an infusion, and administered vasopressors. However, circulatory dynamics could not be maintained. The ventricular septal perforation was repaired directly with mattress sutures through the right ventricle. A small residual ventricular septal perforation was detected, which was repaired with a patch sutured through the left ventricle.

Outcome

The patient was discharged without cardiovascular complications 43 days after admission.

Conclusion

Ventricular septal perforation following blunt chest trauma is a rare form of cardiac trauma. It is important to consider the timing of the operation and the best method to ensure cardiac repair.
Multimodal study of default‐mode network integrity in disorders of consciousness
Authors: Rosazza Cristina , Andronache Adrian , Sattin Davide , Bruzzone Maria Grazia , Marotta Giorgio , Nigri Anna , Ferraro Stefania , Rossi Sebastiano Davide , Porcu Luca , Bersano Anna , Benti Riccardo , Leonardi Matilde , D'Incerti Ludovico , Minati Ludovico ,   on behalf of the Coma Research Center, Besta Institute
Published: March 2016

Objective

Understanding residual brain function in disorders of consciousness poses extraordinary challenges, and imaging examinations are needed to complement clinical assessment. The default‐mode network (DMN) is known to be dysfunctional, although correlation with level of consciousness remains controversial. We investigated DMN activity with resting‐state functional magnetic resonance imaging (rs‐fMRI), alongside its structural and metabolic integrity, aiming to elucidate the corresponding associations with clinical assessment.

Methods

We enrolled 119 consecutive patients: 72 in a vegetative state/unresponsive wakefulness state (VS/UWS), 36 in a minimally conscious state (MCS), and 11 with severe disability. All underwent structural MRI and rs‐fMRI, and a subset also underwent 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET). Data were analyzed with manual and automatic approaches, in relation to diagnosis and clinical score.

Results

Excluding the quartile with largest head movement, DMN activity was decreased in VS/UWS compared to MCS, and correlated with clinical score. Independent‐component and seed‐based analyses provided similar results, although the latter and their combination were most informative. Structural MRI and FDG‐PET were less sensitive to head movement and had better diagnostic accuracy than rs‐fMRI only when all cases were included. rs‐fMRI indicated relatively preserved DMN activity in a small subset of VS/UWS patients, 2 of whom evolved to MCS. The integrity of the left hemisphere appears to be predictive of a better clinical status.

Interpretation

rs‐fMRI of the DMN is sensitive to clinical severity. The effect is consistent across data analysis approaches, but heavily dependent on head movement. rs‐fMRI could be informative in detecting residual DMN activity for those patients who remain relatively still during scanning and whose diagnosis is uncertain. Ann Neurol 2016;79:841–853
Synthese von Inhaltsstoffen der Amaryllisgewächse und nichtnatürlichen Derivaten
Authors: Ghavre Mukund , Froese Jordan , Pour Milan , Hudlicky Tomas
Published: March 2016

Dieser Aufsatz behandelt die Fortschritte bei der Synthese von Amaryllidaceae‐Alkaloiden seit der Veröffentlichung des letzten umfassenden Übersichtsartikels im Jahr 2008. Synthesen der Hauptinhaltsstoffe – Pancratistatin, 7‐Desoxypancratistatin, Narciclasin, Lycoricidin und Lycorin – sowie anderer natürlicher Inhaltsstoffe und nichtnatürlicher Derivate werden vorgestellt, und die biologische Aktivität der nichtnatürlichen Derivate wird diskutiert. Ein Ausblick und weitere Entwicklungen auf dem Gebiet beschließen den Aufsatz. Die Literatur wurde bis Ende August 2015 berücksichtigt.
Ein‐ oder Zwei‐Elektronen‐Transfer? – Zur Bestimmung des Entladeprodukts in Natrium‐Sauerstoff‐Batterien
Authors: Bender Conrad L. , Schröder Daniel , Pinedo Ricardo , Adelhelm Philipp , Janek Jürgen
Published: March 2016

Wiederaufladbare Lithium‐ und Natrium‐Sauerstoff‐Batterien gelten als mögliche zukünftige Energiespeicher. Während die ablaufende Zellreaktion für die aprotische Lithium‐Sauerstoff‐Batterie (Bildung von Li2O2) eindeutig geklärt ist, gibt es widersprüchliche Berichte zum Entladeprodukt in der aprotischen Natrium‐Sauerstoff‐Batterie. Beim Entladen können Na2O2 und NaO2 entstehen, die in ihrer freien Bildungsenthalphie kaum verschieden sind. Die Zahl der übertragenen Elektronen und die Kinetik unterscheiden sich jedoch sehr stark. Beide Oxide werden unabhängig voneinander als Entladeprodukt der aprotischen Natrium‐Sauerstoff‐Batterie beschrieben. Es ist jedoch bisher ungeklärt, ob und wie sich die Entladungsreaktion so beeinflussen lässt, dass selektiv der Ein‐ oder Zwei‐ Elektronen‐Transfer erfolgt. Wir fassen die vorhandenen Daten zusammen, analysieren wichtige Einflussfaktoren auf die Zellreaktionen und zeigen Perspektiven auf. Eine entscheidende Rolle scheinen Wasser und Protonen zu spielen.
Controllable Encapsulation of “Clean” Metal Clusters within MOFs through Kinetic Modulation: Towards Advanced Heterogeneous Nanocatalysts
Authors: Liu Hongli , Chang Lina , Bai Cuihua , Chen Liyu , Luque Rafael , Li Yingwei
Published: March 2016

Surfactant‐free tiny Pt clusters were successfully encapsulated within MOFs with controllable size and spatial distribution by a novel kinetically modulated one‐step strategy. Our synthesis relies on the rational manipulation of the reduction rate of Pt ions and/or the growth rate of MOFs by using H2 as assistant reducing agent and/or acetic acid as MOF‐formation modulator. The as‐prepared Pt@MOF core–shell composites exhibited exceedingly high activity and excellent selectivity in the oxidation of alcohols as a result of the ultrafine “clean” Pt clusters, as well as interesting molecular‐sieving effects derived from the outer platinum‐free MOF shell.
Verstärkte Fibrillen‐Fragmentierung N‐terminal verkürzter, Pyroglutamat‐modifizierter Aβ‐Peptide
Authors: Wulff Melanie , Baumann Monika , Thümmler Anka , Yadav Jay K. , Heinrich Liesa , Knüpfer Uwe , Schlenzig Dagmar , Schierhorn Angelika , Rahfeld Jens‐Ulrich , Horn Uwe , Balbach Jochen , Demuth Hans‐Ulrich , Fändrich Marcus
Published: March 2016

N‐terminal verkürzte, Pyroglutamat‐modifizierte Varianten des Aβ‐Peptids sind natürlich vorkommende chemische Modifikationen bei der Alzheimerschen Krankheit. Wir zeigen hier, dass die beiden Modifikationen die Länge der Fibrillen und den Übergangsmittelpunkt der thermischen Entfaltung der Fibrillen signifikant herabsetzen. Die Peptidkonformation in den Fibrillen bleibt jedoch weitestgehend unbeeinflusst. Diese Beobachtung lässt darauf schließen, dass der unmodifizierte N‐Terminus die Fibrillen vor mechanischem Stress und Fragmentierung schützt. Sie erklärt ebenfalls die hohe Wahrscheinlichkeit von Pyroglutamat‐modifiziertem Peptid, kleinere, besonders toxische Aggregate zu bilden.
Gold‐katalysierte 1,2‐Difunktionalisierung von Alkinen mit sichtbarem Licht ohne zusätzlichen Photosensibilisator
Authors: Huang Long , Rudolph Matthias , Rominger Frank , Hashmi A. Stephen K.
Published: March 2016

Die durch Bestrahlung mit sichtbarem Licht induzierte, Gold‐katalysierte intermolekulare Difunktionalisierung von Alkinen mit Aryldiazoniumsalzen in MeOH liefert verschiedene α‐Arylketone in moderaten bis guten Ausbeuten. Im Unterschied zu vorangegangenen Berichten zu auf Redoxzyklen beruhenden Gold‐katalysierten Reaktionen werden keine Oxidantien oder Photosensibilisatoren benötigt. Die Reaktion läuft unter milden Bedingungen ab und zeigt eine breite Toleranz gegenüber funktionellen Gruppen. Weitere Anwendungen dieses Protokolls demonstrieren die allgemeine Anwendbarkeit der Arylierung einer Vinylgold‐Zwischenstufe anstelle des normalerweise benutzten Protodemetallierungsschrittes. Dies ermöglicht den leichten Zugang zu höher funktionalisierten Produkten in Eintopfreaktionen. Mit einem P,N‐zweizähnigen Liganden wurde die stabile Arylgold(III)‐Spezies erhalten – der überhaupt erste experimentelle Nachweis für die allgemein postulierte direkte oxidative Addition von Aryldiazoniumsalzen an einen Pyridin‐Phosphin‐Gold(I)‐Komplex.
Visible‐Light‐Induced Photoredox Catalysis of Dye‐Sensitized Titanium Dioxide: Selective Aerobic Oxidation of Organic Sulfides
Authors: Lang Xianjun , Zhao Jincai , Chen Xiaodong
Published: March 2016

TiO2 photoredox catalysis has recently attracted much interest for use in performing challenging organic transformations under mild reaction conditions. However, the reaction scheme is hampered by the fact that TiO2 can only be excited by UV light of wavelengths λ shorter than 385 nm. One promising strategy to overcome this issue is to anchor an organic, preferably metal‐free dye onto the surface of TiO2. Importantly, we observed that the introduction of a catalytic amount of the redox mediator TEMPO [(2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl] ensured the stability of the anchored dye, alizarin red S, thereby resulting in the selective oxidation of organic sulfides with O2. This result affirms the essential role of the redox mediator in enabling the organic transformations by visible‐light photoredox catalysis.
Total Synthesis of Cryptocaryol A by Enantioselective Iridium‐Catalyzed Alcohol C−H Allylation
Authors: Perez Felix , Waldeck Andrew R. , Krische Michael J.
Published: March 2016

The polyketide natural product cryptocaryol A is prepared in 8 steps via iridium catalyzed enantioselective diol double C−H allylation, which directly generates an acetate‐based triketide stereodiad. In 4 previously reported total syntheses, 17–28 steps were required.
Identifying Reactive Sites and Transport Limitations of Oxygen Reactions in Aprotic Lithium‐O2 Batteries at the Stage of Sudden Death
Authors: Wang Jiawei , Zhang Yelong , Guo Limin , Wang Erkang , Peng Zhangquan
Published: March 2016

Discharging of the aprotic Li‐O2 battery relies on the O2 reduction reaction (ORR) forming solid Li2O2 in the positive electrode, which is often characterized by a sharp voltage drop (that is, sudden death) at the end of discharge, delivering a capacity far below its theoretical promise. Toward unlocking the energy capabilities of Li‐O2 batteries, it is crucial to have a fundamental understanding of the origin of sudden death in terms of reactive sites and transport limitations. Herein, a mechanistic study is presented on a model system of Au|Li2O2|Li+ electrolyte, in which the Au electrode was passivated with a thin Li2O2 film by discharging to the state of sudden death. Direct conductivity measurement of the Li2O2 film and in situ spectroscopic study of ORR using 18O2 for passivation and 16O2 for further discharging provide compelling evidence that ORR (and O2 evolution reaction as well) occurs at the buried interface of Au|Li2O2 and is limited by electron instead of Li+ and O2 transport.
Light‐Modulated Intermittent Wave Groups in a Diffusively Fed Reactive Gel
Authors: Luo Hainan , Wang Chenlong , Ren Lin , Gao Qingyu , Pan Changwei , Epstein Irving R.
Published: March 2016

Inspired by the biological growth that takes place in time‐varying external fields such as light or temperature, we design an open reaction‐diffusion system in order to investigate growth dynamics. The system is composed of the Belousov–Zhabotinsky (BZ) oscillatory reaction coupled with a copolymer gel consisting of NIPAAm and a photosensitive ruthenium catalyst. When subject to a unidirectional flow of the BZ reactants, the system displays groups of chemical waves whose structure depends upon the period and amplitude of illumination. Simulations of a modified six‐variable Oregonator model exhibit all the complex wave groups found in our experiments. Studying this growth structure may aid in understanding the influence of periodic environmental variation on complex growth processes in living systems.
Schnelles Entdecken photokatalytischer Reaktionen durch mechanismusbasiertes Screening
Authors: Hopkinson Matthew N. , Gómez‐Suárez Adrián , Teders Michael , Sahoo Basudev , Glorius Frank
Published: March 2016

Ein konzeptionell neuartiger mechanismusbasierter Screeningansatz zur schnellen Entdeckung photokatalytischer Reaktionen wird beschrieben. Im Unterschied zu herkömmlichen Screeningmethoden, in denen die gesamte Reaktion betrachtet wird, wird bei diesem Ansatz nur ein einzelner mechanistischer Schritt einer katalytischen Reaktion analysiert. Durch Verwendung von Lumineszenzspektroskopie zur Identifizierung des Quenching‐Schlüsselschritts in photokatalytischen Reaktionen wurden in einem initialen Screening von 100 Komponenten zwei vielversprechende Substratklassen identifiziert. Ein zweites, fokussierteres Screening lieferte mechanistische Einblicke, die zur Entwicklung von Proof‐of‐Concept‐Reaktionen verwendet wurden. Zusammenfassend erleichtert diese schnelle und intuitive Herangehensweise die Entdeckung und Entwicklung neuer photokatalytischer Reaktionen.
Modulare Klick‐Synthese von bifunktionalen, polymeren Heterodimetallkatalysatoren
Authors: Wang Wenlong , Zhao Liyuan , Lv Hui , Zhang Guodong , Xia Chungu , Hahn F. Ekkehardt , Li Fuwei
Published: March 2016

Heterodimetallkomplexe oder strikt alternierend metallierte Polymere wurden durch Klick‐Reaktion von einkernigen Metallkomplexen (sekundäre Baueinheiten, SBUs) erhalten, die NHCs mit p‐Azidophenyl‐ oder p‐Ethinyl‐Substituenten an den Ringstickstoffatomen tragen. Ist eine der SBUs ein NHC‐Kupfer‐Komplex, sind keine weiteren Additive für die Bildung der molekularen oder polymeren Verbindungen nötig, da der Kupferkomplex die Klick‐Reaktion katalysiert. Die Transmetallierung ausgehend von Cu/Ag‐Verbindungen ermöglicht die Synthese von Cu/Pd‐Derivaten. Die Brückengruppe zwischen den SBU‐Einheiten (flexibel oder rigide) beeinflusst die katalytische Aktivität der Heterodimetallverbindungen. Das Polymer mit alternierenden NHC‐Kupfer‐ und NHC‐Silber‐Einheiten sowie einer flexiblen Methylen‐Triazol‐Brücke dazwischen zeigt die höchste Aktivität bei der katalytischen Alkinylierung von Trifluormethylketonen zu fluorierten Propargylalkoholen.
Asymmetric Enzymatic Synthesis of Allylic Amines: A Sigmatropic Rearrangement Strategy
Authors: Prier Christopher K. , Hyster Todd K. , Farwell Christopher C. , Huang Audrey , Arnold Frances H.
Published: March 2016

Sigmatropic rearrangements, while rare in biology, offer opportunities for the efficient and selective synthesis of complex chemical motifs. A “P411” serine‐ligated variant of cytochrome P450BM3 has been engineered to initiate a sulfimidation/[2,3]‐sigmatropic rearrangement sequence in whole E. coli cells, a non‐natural function for any enzyme, providing access to enantioenriched, protected allylic amines. Five mutations in the enzyme substantially enhance its activity toward this new function, demonstrating the evolvability of the catalyst toward challenging nitrene transfer reactions. The evolved catalyst additionally performs the highly enantioselective imidation of non‐allylic sulfides.
Diastereodivergent Reverse Prenylation of Indole and Tryptophan Derivatives: Total Synthesis of Amauromine, Novoamauromine, and epi‐Amauromine
Authors: Müller Jonas M. , Stark Christian B. W.
Published: March 2016

A regio‐ and stereoselective reverse prenylation of indole and tryptophan derivatives is presented. All four possible stereoisomers are accessible through this iridium‐catalyzed reaction. The stereoselectivity is controlled by a chiral phosphoramidite ligand in combination with an achiral borane additive and can be switched by changing the nature of the borane. One enantiomer of the ligand is thus sufficient to prepare all possible isomers. The synthetic potential of this method was demonstrated by a short total synthesis of amauromine and its two natural diastereomers.
One‐ or Two‐Electron Transfer? The Ambiguous Nature of the Discharge Products in Sodium–Oxygen Batteries
Authors: Bender Conrad L. , Schröder Daniel , Pinedo Ricardo , Adelhelm Philipp , Janek Jürgen
Published: March 2016

Rechargeable lithium–oxygen and sodium–oxygen cells have been considered as challenging concepts for next‐generation batteries, both scientifically and technologically. Whereas in the case of non‐aqueous Li/O2 batteries, the occurring cell reaction has been unequivocally determined (Li2O2 formation), the situation is much less clear in the case of non‐aqueous Na/O2 cells. Two discharge products, with almost equal free enthalpies of formation but different numbers of transferred electrons and completely different kinetics, appear to compete, namely NaO2 and Na2O2. Cells forming either the superoxide or the peroxide have been reported, but it is unclear how the cell reaction can be influenced for selective one‐ or two‐electron transfer to occur. In this Minireview, we summarize available data, discuss important control parameters, and offer perspectives for further research. Water and proton sources appear to play major roles.
Enhanced Fibril Fragmentation of N‐Terminally Truncated and Pyroglutamyl‐Modified Aβ Peptides
Authors: Wulff Melanie , Baumann Monika , Thümmler Anka , Yadav Jay K. , Heinrich Liesa , Knüpfer Uwe , Schlenzig Dagmar , Schierhorn Angelika , Rahfeld Jens‐Ulrich , Horn Uwe , Balbach Jochen , Demuth Hans‐Ulrich , Fändrich Marcus
Published: March 2016

N‐terminal truncation and pyroglutamyl (pE) formation are naturally occurring chemical modifications of the Aβ peptide in Alzheimer's disease. We show herein that these two modifications significantly reduce the fibril length and the transition midpoint of thermal unfolding of the fibrils, but they do not substantially perturb the fibrillary peptide conformation. This observation implies that the N terminus of the unmodified peptide protects Aβ fibrils against mechanical stress and fragmentation and explains the high propensity of pE‐modified peptides to form small and particularly toxic aggregates.
Photosensitizer‐Free Visible‐Light‐Mediated Gold‐Catalyzed 1,2‐Difunctionalization of Alkynes
Authors: Huang Long , Rudolph Matthias , Rominger Frank , Hashmi A. Stephen K.
Published: March 2016

Under visible‐light irradiation, the gold‐catalyzed intermolecular difunctionalization of alkynes with aryl diazonium salts in methanol affords a variety of α‐aryl ketones in moderate to good yields. In contrast to previous reports on gold‐catalyzed reactions that involve redox cycles, no external oxidants or photosensitizers are required. The reaction proceeds smoothly under mild reaction conditions and shows broad functional‐group tolerance. Further applications of this method demonstrate the general applicability of the arylation of a vinyl gold intermediate instead of the commonly used protodemetalation step. This step provides facile access to functionalized products in one‐pot processes. With a P,N‐bidentate ligand, a stable aryl gold(III) species was obtained, which constitutes the first direct experimental evidence for the commonly postulated direct oxidative addition of an aryl diazonium salt to a pyridine phosphine gold(I) complex.
Straightforward Hantzsch four‐ and three‐component condensation in the presence of triphenyl(propyl‐3‐sulfonyl)phosphoniumtrifluoromethanesulfonate {[TPPSP]OTf} as a reusable and green mild ionic liquid catalyst
Authors: Vahdat Seyed Mohammad , Zolfigol Mohammad Ali , Baghery Saeed
Published: March 2016

Triphenyl(propyl‐3‐sulfonyl)phosphoniumtrifluoromethanesulfonate {[TPPSP]OTf} as a reusable, green and benign ionic liquid catalyst has been used in the Hantzsch four‐component (synthesis of polyhydroquinolines) and three‐component (synthesis of acridines) condensation reactions of 1,3‐diones, β‐ketoesters, aldehydes, ammonium acetate and aniline derivatives in the presence of 0.5 mol% of {[TPPSP]OTf} at room temperature under solvent‐free conditions. The new ionic liquid catalyst was fully characterized using infrared, 1H NMR, 13C NMR, 31P NMR, 19F NMR and mass spectroscopies, and thermogravimetric and derivative thermogravimetric analyses. Additionally, the recovered catalyst can be recycled at least five times in subsequent reactions without significant loss in catalytic activity. The new synthesis technique presented offers numerous advantages of safety, mild conditions, simplicity, short reaction time, high yields and easy workup compared to the traditional synthesis method. Twenty products have been reported for the first time. Copyright © 2016 John Wiley & Sons, Ltd.
Green synthesis and characterization of monodispersed silver nanoparticles obtained using oak fruit bark extract and their antibacterial activity
Authors: Veisi Hamed , Hemmati Saba , Shirvani Hooman , Veisi Hojat
Published: March 2016

Green synthesis of silver nanoparticles (Ag NPs) has been achieved using oak fruit bark extract as a reducing, capping and stabilizing agent. The biosynthesized Ag NPs were characterized using various techniques. UV–visible spectrum of prepared silver colloidal solution showed absorption maximum at 433 nm. X‐ray diffraction and transmission electron microscopy analysis revealed that Ag NPs have a face‐centred cubic structure being spherical in shape with an average particle size of 20–25 nm. The toxicity of the Ag NPs was tested on bacterial species such as Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli by comparison based on diameter of inhibition zone in disc diffusion tests and minimum inhibitory concentration and minimum bactericidal concentration of NPs dispersed in liquid cultures. The antimicrobial activity of Ag NPs was greater towards Gram‐positive bacteria (S. aureus and B. subtilis) compared to Gram‐negative bacteria as determined using standard Kirby–Bauer disc diffusion assay and serial dilution. Copyright © 2016 John Wiley & Sons, Ltd.
Design, preparation and characterization of Cu/GA/Fe3O4@SiO2 nanoparticles as a catalyst for the synthesis of benzodiazepines and imidazoles
Authors: Shaabani Ahmad , Sepahvand Heshmatollah , Hooshmand Seyyed Emad , Borjian Boroujeni Mahmoud
Published: March 2016

The synthesis and characterization of an efficient and reusable nanocatalyst, Cu/GA/Fe3O4@SiO2, obtained by ultrasonic‐assisted grafting of guanidineacetic acid on modified Fe3O4@SiO2 core–shell nanocomposite spheres and subsequent immobilization of Cu(II), are described. The catalyst was characterized by means of X‐ray diffraction, scanning and transmission electron microscopies, energy‐dispersive X‐ray spectroscopy, elemental analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry and inductively coupled plasma optical emission spectrometry. The prepared nanocatalyst facilitated an efficient and straightforward friendly procedure for the synthesis of benzodiazepines and imidazoles in ethanol and under solvent‐free conditions, respectively. The nanocatalyst can be easily recovered using a magnet and reused several times without any significant loss of activity. Copyright © 2016 John Wiley & Sons, Ltd.
Palladium–S‐propyl‐2‐aminobenzothioate immobilized on Fe3O4 magnetic nanoparticles as catalyst for Suzuki and Heck reactions in water or poly(ethylene glycol)
Authors: Ghorbani‐Choghamarani Arash , Tahmasbi Bahman , Moradi Parisa
Published: March 2016

A moisture‐ and air‐stable heterogenized palladium catalyst was synthesized by coordination of palladium with S‐propyl‐2‐aminothiobenzamide supported on Fe3O4 magnetic nanoparticles. The prepared nanocatalyst was characterized using Fourier transform infrared, energy‐dispersive X‐ray and inductively coupled plasma atomic emission spectroscopies, X‐ray diffraction, vibrating sample magnetometry, transmission and scanning electron microscopies, dynamic laser scattering and thermogravimetric analysis. This catalyst could be dispersed homogeneously in water or poly(ethylene glycol) and further applied as an excellent nano‐organometal catalyst for Suzuki and Heck reactions. The catalyst was easily separated with the assistance of an external magnet from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency or palladium leaching. The leaching of catalyst was examined using hot filtration and inductively coupled plasma atomic emission spectroscopy. Also, the effects of various reaction parameters on the Suzuki and Heck reactions are discussed. Copyright © 2016 John Wiley & Sons, Ltd.