bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyhedral Oligosilsesquioxanes in Functional Chiral Nanoassemblies
Authors: An Shuguo , Hao Aiyou , Xing Pengyao 
Published: February 2021

AbstractIncorporation of giant molecular nanoparticles with atomic precision into chiral nanoassemblies facilitates the fabrication of functional ordered phases with supramolecular chirality, which remains mysterious. Reported here is the first example of polyhedral oligosilsesquioxane (POSS) derivatives that self‐assemble into well‐defined chiral nanoassemblies. POSSs were covalently conjugated to N‐terminal aromatic amino acids, which self‐assembled into nanohelices and twists with explicit handedness tuned by solvent polarity. Chiral nanoassemblies showed active chiroptical responses including Cotton effects and circularly polarized luminescence. The chiral systems can bind guest molecules by charge‐transfer interactions, whereby self‐assembled structures, chiroptical activities, and luminescent colors were further modulated. The unique coassembly systems were applied for instant information encryption and storage with multiple luminescent displays. This work offers a new protocol for the design of functional chiral materials of POSS by molecular self‐assembly.
Nanospace Engineering of Metal–Organic Frameworks through Dynamic Spacer Installation of Multifunctionalities for Efficient Separation of Ethane from Ethane/Ethylene Mixtures
Authors: Chen Cheng‐Xia , Wei Zhang‐Wen , Pham Tony , Lan Pui Ching , Zhang Lei , Forrest Katherine A. , Chen Sha , Al‐Enizi Abdullah M. , Nafady Ayman , Su Cheng‐Yong , Ma Shengqian 
Published: February 2021

AbstractHerein, a dynamic spacer installation (DSI) strategy has been implemented to construct a series of multifunctional metal—organic frameworks (MOFs), LIFM‐61/31/62/63, with optimized pore space and pore environment for ethane/ethylene separation. In this respect, a series of linear dicarboxylic acids were deliberately installed in the prototype MOF, LIFM‐28, leading to a dramatically increased pore volume (from 0.41 to 0.82 cm3 g−1) and reduced pore size (from 11.1×11.1 Å2 to 5.6×5.6 Å2). The increased pore volume endows the multifunctional MOFs with much higher ethane adsorption capacity, especially for LIFM‐63 (4.8 mmol g−1), representing nearly three times as much ethane as the prototypical counterpart (1.7 mmol g−1) at 273 K and 1 bar. Meanwhile, the reduced pore size imparts enhanced ethane/ethylene selectivity of the multifunctional MOFs. Theoretical calculations and dynamic breakthrough experiments confirm that the DSI is a promising approach for the rational design of multifunctional MOFs for this challenging task.
Chromoselective Photocatalysis Enables Stereocomplementary Biocatalytic Pathways**
Authors: Schmermund Luca , Reischauer Susanne , Bierbaumer Sarah , Winkler Christoph K. , Diaz‐Rodriguez Alba , Edwards Lee J. , Kara Selin , Mielke Tamara , Cartwright Jared , Grogan Gideon , Pieber Bartholomäus , Kroutil Wolfgang 
Published: February 2021

AbstractControlling the selectivity of a chemical reaction with external stimuli is common in thermal processes, but rare in visible‐light photocatalysis. Here we show that the redox potential of a carbon nitride photocatalyst (CN‐OA‐m) can be tuned by changing the irradiation wavelength to generate electron holes with different oxidation potentials. This tuning was the key to realizing photo‐chemo‐enzymatic cascades that give either the (S)‐ or the (R)‐enantiomer of phenylethanol. In combination with an unspecific peroxygenase from Agrocybe aegerita, green light irradiation of CN‐OA‐m led to the enantioselective hydroxylation of ethylbenzene to (R)‐1‐phenylethanol (99 % ee). In contrast, blue light irradiation triggered the photocatalytic oxidation of ethylbenzene to acetophenone, which in turn was enantioselectively reduced with an alcohol dehydrogenase from Rhodococcus ruber to form (S)‐1‐phenylethanol (93 % ee).
A Reconstructed Common Ancestor of the Fatty Acid Photo‐decarboxylase Clade Shows Photo‐decarboxylation Activity and Increased Thermostability
Authors: Sun Yue , Calderini Elia , Kourist Robert 
Published: February 2021

AbstractLight‐dependent enzymes are a rare type of biocatalyst with high potential for research and biotechnology. A recently discovered fatty acid photo‐decarboxylase fromChlorella variabilisNC64A (CvFAP) converts fatty acids to the corresponding hydrocarbons only when irradiated with blue light (400 to 520 nm). To expand the available catalytic diversity for fatty acid decarboxylation, we reconstructed possible ancestral decarboxylases from a set of 12 extant sequences that were classified under the fatty acid decarboxylases clade within the glucose‐methanol choline (GMC) oxidoreductase family. One of the resurrected enzymes (ANC1) showed activity in the decarboxylation of fatty acids, showing that the clade indeed contains several photo‐decarboxylases. ANC1 has a 15 °C higher melting temperature (Tm) than the extant CvFAP. Its production yielded 12‐fold more protein than this wild type decarboxylase, which offers practical advantages for the biochemical investigation of this photoenzyme. Homology modelling revealed amino acid substitutions to more hydrophilic residues at the surface and shorter flexible loops compared to the wild type. Using ancestral sequence reconstruction, we have expanded the existing pool of confirmed fatty acid photo‐decarboxylases, providing access to a more robust catalyst for further development via directed evolution.
Probes for Photoaffinity Labelling of Kinases
Authors: Korovesis Dimitris , Beard Hester A. , Mérillat Christel , Verhelst Steven H. L. 
Published: February 2021

AbstractProtein kinases, one of the largest enzyme superfamilies, regulate many physiological and pathological processes. They are drug targets for multiple human diseases, including various cancer types. Probes for the photoaffinity labelling of kinases are important research tools for the study of members of this enzyme superfamily. In this review, we discuss the design principles of these probes, which are mainly derived from inhibitors targeting the ATP pocket. Overall, insights from crystal structures guide the placement of photoreactive groups and detection tags. This has resulted in a wide variety of probes, of which we provide a comprehensive overview. We also discuss several areas of application of these probes, including the identification of targets and off‐targets of kinase inhibitors, mapping of their binding sites, the development of inhibitor screening assays, the imaging of kinases, and identification of protein binding partners.
Synthesis of Glycodendrimers with Antiviral and Antibacterial Activity
Authors: Hoyos Pilar , Perona Almudena , Juanes Olga , Rumbero Ángel , Hernáiz María J. 
Published: February 2021

AbstractGlycodendrimers are an important class of synthetic macromolecules that can be used to mimic many structural and functional features of cell‐surface glycoconjugates. Their carbohydrate moieties perform key important functions in bacterial and viral infections, often regulated by carbohydrate–protein interactions. Several studies have shown that the molecular structure, valency and spatial organisation of carbohydrate epitopes in glycoconjugates are key factors in the specificity and avidity of carbohydrate–protein interactions. Choosing the right glycodendrimers almost always helps to interfere with such interactions and blocks bacterial or viral adhesion and entry into host cells as an effective strategy to inhibit bacterial or viral infections. Herein, the state of the art in the design and synthesis of glycodendrimers employed for the development of anti‐adhesion therapy against bacterial and viral infections is described.
The Long and Bright Path of a Lanthanide MOF: From Basics towards the Application
Authors: Otal Eugenio Hernán , Tanaka Hideki , Kim Manuela Leticia , Hinestroza Juan Paulo , Kimura Mutsumi 
Published: February 2021

AbstractThe development of portable, reliable, and low‐cost sensors for assessing the quality of natural water sources is of high relevance in developing countries as they can serve as an intermediate solution prior to the building of permanent potable water distribution infrastructure. These sensors should be simple to operate by non‐trained operators and easy to manufacture locally. Lanthanide‐based metal–organic frameworks (MOFs) offer a trustable platform due to their intense emission in regions of the visible spectra and their high sensitivity to fluorides in water. Cotton was chosen as a substrate due to its high hydrophilicity which, together with the highly porous nature of the MOF, allows for shorter reaction times. The modified cotton was characterized by XRD, SEM as well as XAFS, hence probing the presence of [Tb(BTC)6(H2O)] (Tb‐BTC) attachment to cotton. Changes in the emission when Tb‐BTC modified cotton was exposed to water and aqueous fluoride solutions were monitored as a function of time. Crystalline phase changes were identified that correlated to structural information. Finally, the Tb‐BTC modified cotton was used to build a fluoride demonstrator sensor with a linear response of up to 10 mg L−1 and a limit of detection of 0.8 mg L−1, making it suitable for drinking water analysis under international regulations.
Triggering Electron Transfer in Co(I) Dimers: Computational Evidences for a Reversible Disproportionation Mechanism
Authors: Guillaumont Maya , Fourré Isabelle , Pilmé Julien , Halbert Stéphanie , Gérard Hélène 
Published: February 2021

AbstractAn inner‐sphere disproportionation mechanism of the Co(I) precursor CoCl(PPh3)3 is described through a Density Functional Theory study. The essential role of oleylamine in this process is unravelled. A detailed analysis of the electronic structure of Cobalt dimers of the general formula Co2Cl2Ln (L=NH3 and PH3) demonstrates that electron transfer is triggered by asymetric coordination of amine and phosphine to stabilize a mixed‐valence Co(II)−Co(0) dimer. This is consistent with the HSAB statement that both amine and phosphine ligands are required to stabilize the reaction products, respectively Co(II) and Co(0) centers. We propose a quasi‐athermic multi‐step disproportionation mechanism with low activation barriers where the electron transfer goes through simple ligand exchanges between Co.
A Density Functional Theory Study of Optical Rotation in Some Aziridine and Oxirane Derivatives
Authors: Galeano Carrano Ramiro S. , Provasi Patricio F. , Ferraro Marta B. , Alkorta Ibon , Elguero José , Sauer Stephan P. A. 
Published: February 2021

AbstractWe present time‐dependent density functional theory (TDDFT) calculations of the electronic optical rotation (ORP) for seven oxirane and two aziridine derivatives in the gas phase and in solution and compare the results with the available experimental values. For seven of the studied molecules it is the first time that their optical rotation was studied theoretically and we have therefore investigated the influence of several settings in the TDDFT calculations on the results. This includes the choice of the one‐electron basis set, the exchange‐correlation functional or the particular polarizable continuum model (PCM). We can confirm that polarized quadruple zeta basis sets augmented with diffuse functions are necessary for converged results and find that the aug‐pc‐3 basis set is a viable alternative to the frequently employed aug‐cc‐pVQZ basis set. Based on our study, we cannot recommend the generalized gradient functional KT3 for calculations of the ORP in these compounds, whereas the hybrid functional PBE0 gives results quite similar to the long‐range correct CAM−B3LYP functional. Finally, we observe large differences in the solvent effects predicted by the integral equation formalism of PCM and the SMD variant of PCM. For the majority of solute/solvent combinations in this study, we find that the SMD model in combination with the PBE0 functional and the aug‐pc‐3 basis set gives the best agreement with the experimental values.
The Influence of Water Vapor on the Electrochemical Shift of an Ionic Liquid Measured by Ambient Pressure X‐ray Photoelectron Spectroscopy
Authors: Jia Meng , Broderick Alicia , Newberg John T. 
Published: February 2021

AbstractIonic liquids (ILs) are considered to be one of the steppingstones to fabricate next generation electrochemical devices given their unique physical and chemical properties. The addition of water to ILs significantly impact electrochemical related properties including viscosity, density, conductivity, and electrochemical window. Herein we utilize ambient pressure X‐ray photoelectron spectroscopy (APXPS) to examine the impact of water on values of the electrochemical shift (S), which is determined by measuring changes in binding energy shifts as a function of an external bias. APXPS spectra of C 1s, O 1s and N 1s regions are examined for the IL 1‐butyl‐3‐methylimidazolium acetate, [C4mim][OAc], at the IL/gas interface as a function of both water vapor pressure and external bias. Results reveal that in the absence of water vapor there is an IL ohmic drop between the working electrode and quasi reference electrode, giving rise to chemical specific S values of less than one. Upon introducing water vapor, S values approach one as a function of increasing water vapor pressure, indicating a decrease in the IL ohmic drop as the IL/water mixture becomes more conductive and the potential drop is driven by the electric double layer at the electrode/IL interface.
A validated method for the quantification of IOX‐2, a potent prolyl hydroxylase inhibitor in equine urine and plasma using liquid chromatography–high‐resolution mass spectrometry
Authors: Mikhail Ezra , Siccardi Erik , Bawazir Ali , Rajesh Ambika , Prathyush Seetharani , Al Wazani Duaa Mohammad Kamal , Sabeek Muhammed , John Thomas 
Published: February 2021

AbstractIOX‐2 is a potent inhibitor of enzyme prolyl hydroxylases‐2 (PHD) that plays a critical role in regulating hypoxia inducible factor (HIF) abundance and oxygen homeostasis. Federation for Equestrian Sports has listed HIF activators as prohibited substances to prevent their usage in doping. Consequently, it became essential to develop adequate knowledge and testing methods to detect it in equine sports drug testing samples. The validated method utilizes ultra‐high‐performance liquid chromatography coupled to high‐resolution mass spectrometry in order to detect extremely low concentration of the analyte present in both matrices. Confirmation for the presence of the analyte was achieved by comparing ion ratios, retention time, and accurate mass. Method linear range for plasma was between 0.25 to 100 ng/ml, and limit of detection (LOD) was 0.075 ng/ml. The linear range for urine was 0.125 to 100 ng/ml, and LOD was 0.025 ng/ml. Intraday precision at 0.5, 10, and 50 ng/ml was between 4.0% and 9.7% for plasma and 4.2% and 10.4% for urine. Accuracy at 0.5, 10, and 50 ng/ml was between 91% and 94% for plasma and 99% and 103% for urine. Elimination profile of IOX‐2 in equine plasma and urine was carried out using the developed method in which two horses were intravenously administered IOX‐2 and samples were collected. Metabolic profile in plasma and urine was investigated. IOX‐2 was detected for a minimum of 54 and 151 h of post administration in plasma and urine, respectively, thereby providing a valuable tool for evaluating its misuse in equine racing.
Highly Efficient DMSO‐Promoted α‐Hydrolysis of α‐Halohydroxamates under Mild Conditions
Authors: Yoon Lee Chang , Kim Sung‐Gon 
Published: February 2021

AbstractA novel and efficient method for the nucleophilic α‐hydrolysis of α‐halohydroxamates with water under metal‐free conditions is described. In this reaction, the simple and readily available dimethyl sulfoxide (DMSO) was used as a catalyst, while water served as the nucleophile and oxygen source. This method was successfully employed in the synthesis of secondary α‐hydroxy‐α‐alkyl and α‐hydroxy‐α‐arylhydroxamates as well as tertiary α‐hydroxy‐α‐dialkylhydroxamates. Furthermore, the α‐hydrolysis of α‐halo‐α‐dialkylhydroxamates was achieved in the absence of the DMSO catalyst. This is a novel, mild, less toxic, and facile strategy for α‐hydroxylation of amides.
Is opioid therapy for chronic non‐cancer pain associated with a greater risk of all‐cause mortality compared to non‐opioid analgesics? A systematic review of propensity score matched observational studies
Authors: Tölle Thomas , Fitzcharles Mary‐Ann , Häuser Winfried 
Published: February 2021

AbstractBackgroundThe many risks associated with opioid therapy for chronic non‐cancer pain (CNCP) have led to questions about use. This is particularly relevant for risk of increased mortality. However, underlying medical conditions of those using opioids may influence mortality findings due to confounding by indication. Similarly, non‐opioid analgesics are also associated with an increased risk of mortality, too.MethodsWe have conducted a systematic review of propensity score matched observational studies comparing mortality associated with opioid use compared to non‐opioid analgesics. Clinicaltrials.gov, Google Scholar, MEDLINE and Scopus were searched from inception to July 2020. Propensity score matched observational studies comparing opioids to non‐opioid analgesics in real‐world settings were analysed. Primary outcome was pooled adjusted hazard ratio (aHR) of all‐cause death. Effects were summarized by a random effects model.ResultsFour studies with seven study arms and 120,186 patients were analysed. Pooled aHR for all‐cause death was 1.69 (95% confidence interval [CI] 1.47, 1.95). When mortality risk was confined to out‐of‐hospital deaths, the pooled aHR was 2.12 (95% CI 1.46, 3.09). The most frequent cause of death was cardiovascular death. Before matching, patients with opioids were older and had more somatic diseases than patients with non‐opioids. Despite extensive propensity score matchings and sensitivity analyses, all studies could not fully exclude confounding by indication.ConclusionsPossibly, opioids are associated with an increased all‐cause mortality risk compared to non‐opioid analgesics. When considering treatment options for patients with CNCP, the possible risk of increased all‐cause mortality with opioids should be discussed.SignificanceAn increased all‐cause mortality associated with opioid use compared to non‐opioid analgesics for CNCP was identified by a systematic review of four propensity score matched cohort studies in real‐world settings. The number needed to harm for an additional excess death per 10,000 person‐years was 116. Despite extensive propensity score matchings and sensitivity analyses, all studies could not fully exclude confounding by indication. The potential risk of increased all‐cause mortality with opioids should be discussed with patients when considering opioid treatment.
Effects of multifocal transcranial direct current stimulation targeting the motor network during prolonged experimental pain
Authors: Gregoret Luisina , Zamorano Anna M. , Graven‐Nielsen Thomas 
Published: February 2021

Abstract
BackgroundAntinociceptive effects of transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) have been extensively studied in the past years. However, M1 does not work in isolation, but it rather interacts within a network, the so‐called resting‐state motor network.ObjectiveTo explore the anti‐nociceptive effects of a new multifocal tDCS approach administered to regions linked to the resting state motor network (network‐tDCS) compared to sham tDCS.MethodsHealthy individuals were included in this randomized, parallel and double‐blinded study comprising two consecutive interventions with 24‐hr interval of either active (n = 19) or sham (n = 19) network‐tDCS. Prolonged pain was induced by application of topical capsaicin on the dorsum of the hand during a 24‐hr period. Assessments of corticomotor excitability (transcranial magnetic stimulation), pain ratings (numerical rating scale, NRS), skin pain sensitivity on the arm (heat and mechanical), temporal summation of pain (TSP) and conditioned pain modulation (CPM) were performed at baseline (Day1‐baseline), after 25 min of capsaicin application and before the first tDCS session (Day1‐post‐cap), and after the second tDCS session (Day2).ResultsComparing Day2 to Day1‐baseline measures, there was reduced corticomotor excitability (p < .05) and impaired CPM‐effect (p < .05) after sham but not after active network‐tDCS. Pain NRS ratings increased at Day2 compared to Day1‐post‐cap (p < .01) in both groups whereas no significant changes were found in pain sensitivity and TSP.ConclusionsPresent findings demonstrate that tDCS applied over regions linked to the resting state motor network reverts the inhibition of corticomotor excitability and CPM impairment both provoked by prolonged experimental pain for 24 hr.SignificanceThese findings highlight that the stimulation of the resting state motor network with multifocal tDCS may represent a potential cortical target to treat chronic pain, particularly in patients exhibiting maladaptive corticomotor excitability and impaired conditioned pain modulation effects.
A review of postpartum hemorrhage in low‐income countries and implications for strengthening health systems
Authors: Borovac‐Pinheiro Anderson , Priyadarshani Preeti , Burke Thomas F. 
Published: February 2021

AbstractPostpartum hemorrhage (PPH) is the leading cause of maternal morbidity and mortality worldwide. Disparities in PPH‐associated survival between high and low‐/middle‐income countries reflect an imperative for low‐resource countries to improve strategies for rapid diagnosis and treatment. A review of current PPH diagnosis, prevention, treatment, and access to care in low‐income countries has been used to understand, extract, and report the challenges that public health systems face in trying to solve the marked global disparity in PPH outcomes. Improvement in PPH survival begins with holistic strengthening of each step along the continuum of care in health systems and should include performance feedback measures and quality‐of‐care research.
Influence of the human immunodeficiency virus on cervical precancerous lesions
Authors: Nkwabong Elie , Kengne Berenis , Nkene Mawamba Yvette , Sando Zacharie 
Published: February 2021

AbstractObjectiveTo study the influence of HIV status on the occurrence of cervical precancerous lesions (CPL).MethodsThis analytical cross‐sectional study was carried out between December 1, 2019 and May 31, 2020. All women with documented HIV status screened for CPL with biopsies performed were recruited. The main variables recorded included maternal age, educational level, number of sexual partners, age at first sexual intercourse, smoking, alcohol consumption, HIV status, CD4 count, and cervical biopsy result. Fisher exact test and Student's t test were used for comparison. A p value <0.05 was considered statistically significant.ResultsConcerning women attending our screening units, CPL was more frequent among those living with HIV/AIDS (20/92; 21.7%) than among those not living with HIV/AIDS (29/290; 10.0%) (p = 0.004). As regards women living with HIV/AIDS, those with a CD4 count below 350/mL were more at risk of having a CPL (odds ratio [OR] 21.39, 95% confidence interval [CI] 5.60–81.56, p ˂ 0.001). High‐grade lesions (cervical intraepithelial neoplasia Stage 2 or 3) were more often found in women living with HIV/AIDS (OR 3.83, 95% CI 1.09–13.45, p = 0.033).ConclusionMore attention should be paid to women living with HIV/AIDS, especially those with CD4 count less than 350/mL, who should be screened more often with biopsy frequently conducted if indicated.