bluuebunny/crossref_metadata_2025_split huggingface dataset:
Azide⋅⋅⋅Oxygen Interaction: A Crystal Engineering Tool for Conformational Locking
Authors: Madhusudhanan Mithun C. , Balan Haripriya , Werz Daniel B. , Sureshan Kana M. 
Published: August 2021

AbstractWe have designed, synthesized, and crystallized 36 compounds, each containing an azide group and an oxygen atom separated by three bonds. Crystal structure analysis revealed that each of these molecules adopts a conformation in which the azide and oxygen groups orient syn to each other with a short O⋅⋅⋅Nβcontact. Geometry‐optimized structures [using M06‐2X/6–311G(d,p) level of theory] also showed the syn conformation in all 36 of these cases, suggesting that this is not merely a crystal packing effect. Quantum topological analysis using Bader's Atoms in Molecules (AIM) theory revealed bond paths and bond critical points (BCP) in these structures suggesting its nature and energetics to be similar to weak hydrogen bonding. The NCI‐RDG plot clearly revealed the attractive interaction consisting of electrostatic or dispersive components in all the 36 systems. NBO analysis suggested a weak orbital‐relaxation (charge‐transfer) contribution of energy for a few(sp2)O‐donor systems. Natural population analysis (NPA) and molecular electrostatic potential mapping (MESP) of these crystal structures further revealed the existence of favorable azide‐oxygen interaction. A CSD search indicated the frequent and consistent occurrence of this interaction and its role dictating the syn conformation of azide and oxygen in molecules where these groups are separated by 2–4 bonds.
Probing the Extremes of Covalency in M−Al bonds: Lithium and Zinc Aluminyl Compounds
Authors: Roy Matthew M. D. , Hicks Jamie , Vasko Petra , Heilmann Andreas , Baston Anne‐Marie , Goicoechea Jose M. , Aldridge Simon 
Published: August 2021

AbstractSynthetic routes to lithium, magnesium, and zinc aluminyl complexes are reported, allowing for the first structural characterization of an unsupported lithium–aluminium bond. Crystallographic and quantum‐chemical studies are consistent with the presence of a highly polar Li−Al interaction, characterized by a low bond order and relatively little charge transfer from Al to Li. Comparison with magnesium and zinc aluminyl systems reveals changes to both the M−Al bond and the (NON)Al fragment (where NON=4,5‐bis(2,6‐diisopropylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene), consistent with a more covalent character, with the latter complex being shown to react with CO2via a pathway that implies that the zinc centre acts as the nucleophilic partner.
Reversed‐phase‐HPLC enantioseparation and control of enantiomeric purity of duloxetine using a new chiral reagent and recovery of enantiomers
Authors: Vyas Renu , Bhushan Ravi , Nagar Hariom , Sharma Aishwarya 
Published: August 2021

AbstractThis study reports a rapid and low‐cost LC method for control of enantiomeric purity of duloxetine. Though duloxetine, as marketed and administered, is expected to be a single (S)‐enantiomer, the analysis of a few commercial branded samples by the method developed and presented here showed that they contain a relatively high percentage of (R)‐enantiomer (e.g., 2.71–5.42%, which is undesirable in drug formulations). A new chiral derivatizing reagent [isatinyl‐(S)‐naproxen amide] was synthesized on (S)‐naproxen platform. Diastereomeric derivatives were synthesized under microwave irradiation and were separated using reversed‐phase‐HPLC on a C18 column. A combination of acetonitrile and triethylammonium phosphate buffer (9 mM, pH 4) as the mobile phase and detection at 273 nm were found successful. The diastereomeric derivatives at preparative scale were separated using open column chromatography, and the native enantiomers were obtained and characterized. The HPLC separation method was validated for detection limit, linearity, accuracy, and precision. The limits of detection of (S,R)‐diastereomer and (S,S)‐diastereomer were found to be 12 and 16 pg/mL, respectively, for the 20‐μL injected volume. The method so developed has a practical significance and greater societal impact in establishing the control of enantiomeric purity and in ensuring the enantiomeric purity of the drug meant for human consumption.
Community dimensions and emotions in the era of COVID‐19
Authors: Marzana Daniela , Novara Cinzia , De Piccoli Norma , Cardinali Paola , Migliorini Laura , Di Napoli Immacolata , Guidi Elisa , Fedi Angela , Rollero Chiara , Agueli Barbara , Esposito Ciro , Marta Elena , González Leone Florencia , Guazzini Andrea , Meringolo Patrizia , Arcidiacono Caterina , Procentese Fortuna 
Published: August 2021

AbstractFollowing an ecological perspective, reactions to a disaster—such as the COVID‐19 pandemic—should be analysed in the interdependence between individual and community dimensions. The present study aims to analyse individual emotional dimensions (anxiety, joy, fear or depressive feelings) and their community dimensions (connectedness, emotional sharing and solidarity) with a longitudinal approach among university students from Italian universities. Participants were 746 university students at t1 (during the lockdown) and 361 at t2 (after the lockdown) recruited in six Italian universities from different areas of Italy. Comparing emotional dimensions in the two times, t2 is characterized by a generalized ambiguity: both happiness or joy because of the end of limitations and a kind of ‘post‐lockdown anxiety’ because of a sense of individual inadequacy in facing the return to normality, conducting daily activities and attending community spaces. Data confirms that after the so‐called ‘honeymoon phase’ in community dimensions (first phase of t1 time), a sort of ‘depressive reaction’ arises at t2: Italian university students seem more aware of the need for individual and social responsibility and that many events are not under their personal control. The reconstruction phase and exit from the emergency are perceived as necessary but also as a difficult and risky period. Please refer to the Supplementary Material section to find this article's Community and Social Impact Statement.
Characterization of a Novel Mesophilic CTP‐Dependent Riboflavin Kinase and Rational Engineering to Create Its Thermostable Homologues**
Authors: Kumar Yashwant , Singh Reman Kumar , Hazra Amrita Brajagopal 
Published: August 2021

AbstractFlavins play a central role in metabolism as molecules that catalyze a wide range of redox reactions in living organisms. Several variations in flavin biosynthesis exist among the domains of life, and their analysis has revealed many new structural and mechanistic insights till date. The cytidine triphosphate (CTP)‐dependent riboflavin kinase in archaea is one such example. Unlike most kinases that use adenosine triphosphate, archaeal riboflavin kinases utilize CTP to phosphorylate riboflavin and produce flavin mononucleotide. In this study, we present the characterization of a new mesophilic archaeal CTP‐utilizing riboflavin kinase homologue from Methanococcus maripaludis (MmpRibK), which is linked closely in sequence to the previously characterized thermophilic Methanocaldococcus jannaschii homologue. We reconstitute the activity of MmpRibK, determine its kinetic parameters and molecular factors that contribute to its unique properties, and finally establish the residues that improve its thermostability using computation and a series of experiments. Our work advances the molecular understanding of flavin biosynthesis in archaea by the characterization of the first mesophilic CTP‐dependent riboflavin kinase. Finally, it validates the role of salt bridges and rigidifying amino acid residues in imparting thermostability to this unique structural fold that characterizes archaeal riboflavin kinase enzymes, with implications in enzyme engineering and biotechnological applications.
Raynaud's phenomenon secondary to erenumab in a patient with chronic migraine
Authors: Manickam Agaath Hedina , Buture Alina , Tomkins Esther , Ruttledge Martin 
Published: August 2021

AbstractRaynaud's phenomenon is a rare side effect of CGRP monoclonal antibodies. These molecular treatments are a relatively new class of drugs for the prevention of migraine. It is likely that we will see this side effect more often in the future. Patients with a background of Raynaud's phenomenon may experience worsening of their symptoms if started on these treatments.
Endoscopic resection of a large polypoid gastric heterotopia of duodenum: a case report
Authors: Maione Francesco , Chini Alessia , Gennarelli Nicola , Milone Marco , Manigrasso Michele , Guadagno Elia , Aprea Giovanni , De Palma Giovanni Domenico 
Published: August 2021

AbstractThis report shows a rare case of gastric heterotopia in the duodenum presented as a large polypoid lesion, differently from data reported in literature, which enters into differential diagnosis with other duodenal lesions that are not always benign.
Pheochromocytoma presenting with severe abdominal pain and abnormal liver enzymes
Authors: Habib Mhd Baraa , Abdelrazek Mohamed , Alatasi Sali , Mohamed Mouhand F. H. , Ali Hamda , Hamad Mohamad Khair 
Published: August 2021

AbstractPheochromocytoma can present with right hypochondrial pain, elevated liver enzymes, and a misleading appearance on ultrasound scan mimicking hepatic mass due to the proximity of adrenal masses to the liver.
COVID‐19 reinfection or reactivation in a renal transplant patient
Authors: Abolghasemi Sara , Zolfaghari Farnaz , Naeimipoor Mohammad , Azhdari Tehrani Hamed , Hakamifard Atousa 
Published: August 2021

AbstractRecurrences of COVID‐19 infection may occur in immunocompromised patients. Reinfection or reactivation of COVID‐19 virus is a challenging issue in these patients.
Formaldehyde‐Crosslinked Nontoxic Aβ Monomers to Form Toxic Aβ Dimers and Aggregates: Pathogenicity and Therapeutic Perspectives
Authors: Zhao Hang , Huang Xuerong , Tong Zhiqian 
Published: August 2021

AbstractAlzheimer's disease (AD) is characterized by the presence of senile plaques in the brain. However, medicines targeting amyloid‐beta (Aβ) have not achieved the expected clinical effects. This review focuses on the formation mechanism of the Aβ dimer (the basic unit of oligomers and fibrils) and its tremendous potential as a drug target. Recently, age‐associated formaldehyde and Aβ‐derived formaldehyde have been found to crosslink the nontoxic Aβ monomer to form the toxic dimers, oligomers and fibrils. Particularly, Aβ‐induced formaldehyde accumulation and formaldehyde‐promoted Aβ aggregation form a vicious cycle. Subsequently, formaldehyde initiates Aβ toxicity in both the early‐and late‐onset AD. These facts also explain why AD drugs targeting only Aβ do not have the desired therapeutic effects. Development of the nanoparticle‐based medicines targeting both formaldehyde and Aβ dimer is a promising strategy for improving the drug efficacy by penetrating blood‐brain barrier and extracellular space into the cortical neurons in AD patients.
A parallel hardware hypervisor for hardware‐accelerated cloud computing
Authors: Doğan Atakan , Ebcioğlu Kemal 
Published: August 2021

SummaryHardware‐accelerated cloud computing systems based on FPGA or ASIC chips have proved useful in providing power‐efficient acceleration for a variety of software applications. However, these computing systems rely on operating systems and hypervisors, which not only are implemented with inefficient software, but which also are incapable of handling massively parallel systems, due to the lack of parallelism and scalability in their algorithmic designs. As a result, power, performance, and scalability problems will emerge in an exascale cloud computing environment. As a solution to these problems, the present study proposes a parallel hardware hypervisor system implemented entirely in special‐purpose hardware without resorting to energy‐inefficient general‐purpose processors. Furthermore, the proposed hypervisor system virtualizes application‐specific multi‐chip supercomputers, in order to enable the virtual supercomputers to share available FPGA and semi‐configurable ASIC resources in a cloud system. Single‐chip verification studies based on Verilog simulation have been done to verify the functional correctness of the proposed hardware hypervisor system, which consumes only a fraction of hardware resources. This article will in particular focus on the virtualization of multi‐chip message‐passing based supercomputers using limited reconfigurable hardware resources.
Transthyretin as a target of alkylation and a potential biomarker for sulfur mustard poisoning: Electrophoretic and mass spectrometric identification and characterization
Authors: Schmeißer Wolfgang , Lüling Robin , Steinritz Dirk , Thiermann Horst , Rein Theo , John Harald 
Published: August 2021

AbstractFor the verification of exposure to the banned blister agent sulfur mustard (SM) and the better understanding of its pathophysiology, protein adducts formed with endogenous proteins represent an important field of toxicological research. SM and its analogue 2‐chloroethyl ethyl sulfide (CEES) are well known to alkylate nucleophilic amino acid side chains, for example, free‐thiol groups of cysteine residues. The specific two‐dimensional thiol difference gel electrophoresis (2D‐thiol‐DIGE) technique making use of maleimide dyes allows the staining of free cysteine residues in proteins. As a consequence of alkylation by, for example, SM or CEES, this staining intensity is reduced. 2D‐thiol‐DIGE analysis of human plasma incubated with CEES and subsequent matrix‐assisted laser desorption/ionization time‐of‐flight (tandem) mass‐spectrometry, MALDI‐TOF MS(/MS), revealed transthyretin (TTR) as a target of alkylating agents. TTR was extracted from SM‐treated plasma by immunomagnetic separation (IMS) and analyzed after tryptic cleavage by microbore liquid chromatography‐electrospray ionization high‐resolution tandem‐mass spectrometry (μLC‐ESI MS/HR MS). It was found that the Cys10‐residue of TTR present in the hexapeptide C(‐HETE)PLMVK was alkylated by the hydroxyethylthioethyl (HETE)‐moiety, which is characteristic for SM exposure. It was shown that alkylated TTR is stable in plasma in vitro at 37°C for at least 14 days. In addition, C(‐HETE)PLMVK can be selectively detected, is stable in the autosampler over 24 h, and shows linearity in a broad concentration range from 15.63 μM to 2 mM SM in plasma in vitro. Accordingly, TTR might represent a complementary protein marker molecule for the verification of SM exposure.
Layered Yttrium Hydroxide as a Host for Enhancing the UV‐Protective Capacity and Photostability of Benzophenone‐5
Authors: Choi Juyeong , Kim Hyunsub , Byeon Song‐Ho 
Published: August 2021

AbstractLayered yttrium hydroxide (LYH) was explored as a host material for a highly efficient organic UV‐absorber, 2‐hydroxy‐4‐methoxybenzophenone‐5‐sulfonic acid (BP5), with the intercalation of BP5 anions into the interlayer galleries of LYH. On the basis of the powder X‐ray diffraction (XRD) pattern and Infrared (IR) spectra of the resulting BP5‐LYH hybrid, it was suggested that the double aromatic rings of BP5 anion are arranged parallel to the hydroxocation layers in the interlayer space in LYH. Thermogravimetry (TG) curves indicated the incomplete inclusion of BP5 anions due to the insufficiency of the lateral area of the interlayer space in LYH to accommodate the parallel arrangement of fully exchanged BP5 anions. The UV absorption band of BP5 was so broad as to absorb over the full UV range after intercalation in the LYH host. Long‐term use tests showed that BP5 was not significantly released from the LYH matrix in artificial seawater. This hybrid was well dispersed in a PVA solution to produce transparent BP5‐LYH/PVA composite UV‐filter films. The BP5‐LYH hybrid exhibited excellent photostability in PVA composites, maintaining complete UV‐filtering performance under simulated sunlight. A BP5‐LYH hybrid could therefore be a promising candidate not only as a UV‐filter that does not release BP5 into aquatic systems but also as a transparent outdoor UV‐screening polymer film whose single species covers the full UV range.
Analysis of Dynamic Changes of Lipid Composition and Structure of Deep‐Fried Pork Slices during Storage
Authors: Guo Xi‐Juan , Wang Rui‐Qi 
Published: August 2021

AbstractTo understand the reasons for the quality deterioration of traditional battered and deep‐fried pork slices during storage, fried pork slices stored for 12 h at 0–40 °C are used as the research samples, and Fourier‐transform infrared spectroscopy （FTIR） and gas chromatography‐mass spectrometry （GC‐MS） are used as analytical methods. The oil migration mode, fatty acid composition change, and functional group changes in the meat slices are analyzed. The experimental results show that the unsaturated fatty acid (USFA) in the starch paste enters the meat slice in a single diffusion mode during storage, and the migration direction of the fatty acid is reversed after 7 h. Oxidation mainly occurs after 4 h of storage. At this time, the absorption peak intensities of the C═C, OH, CH2, and CH3 groups began to increase significantly. After 8 h, the characteristic peak of C═O narrowed and disappeared after 12 h, indicating that the oxidation has entered a decline period. The content of USFA and linoleic acid (C18:2) showed a downward trend in phospholipids. Therefore, the stability of phospholipids, especially linoleic acid, plays an important role in the edibility of meat slices during storage.Practical Applications: Many studies have demonstrated that the edible quality of fried meat products decreases gradually during storage and the change in lipid content is the main reason for this phenomenon. However, there is a lack of targeted studies on lipid migration and compositional and structural changes during the storage of deep‐fried foods. In this study, dynamic mobility, dynamic modeling, and changes in fatty acid composition and structure of lipids before and after storage provide data support for the implementation of targeted improvement measures to reduce oil migration, oxidation, and decomposition, and thus effectively extend the consumption cycle.
Upward flame spread and self‐induced buoyant blow‐off over two‐sided thin fabric at different inclination angles
Authors: Gao Yunji , Yang Xiaolong , Luo Yueyang , Guo Feng , Zhang Yuchun , Gong Liang 
Published: August 2021

SummaryA series of upward flame spread experiments over two‐sided long thin flax fabric sheets were conducted at different inclination angles from horizontal (0°) to vertical (90°). With the inclination increased to a critical angle, the flame on the lower side of the 4 and 6 cm wide samples can be blown off spontaneously. After the lower‐side blow‐off, the remained flame on the upper side spread steadily to the end of the sample. To clarify the controlling mechanism, the flame spread rates and flame geometry characteristics were investigated and compared in different inclination angles. The maximum flame spread rate and flame length monotonically increased with the inclination angle under the assistance of self‐induced buoyancy. However, the steady flame spread rate and flame length on the remained side dropped significantly after one‐side extinction. The lower side flame was blown off by the large buoyant flow velocity induced from the critical flame length, which is controlled by the small Damköhler number. Flame thickness and flame tilt angle were analyzed at varied inclinations to help understand the heat transfer from the flame to the unburnt fuel surface. Two opposite effects of self‐induced buoyancy were proposed at different ranges of inclination: the thermal assistance regime at the lower inclination angle and the kinetical extinguishing regime at a higher inclination angle. They are dominated by the heat transfer from the flame and local fluid dynamic around the flame base, respectively.
Robust and efficient multilevel‐ILU preconditioning of hybrid Newton–GMRES for incompressible Navier–Stokes equations
Authors: Chen Qiao , Jiao Xiangmin , Yang Oliver 
Published: August 2021

AbstractWe introduce a robust and efficient preconditioner for a hybrid Newton–GMRES method for solving the nonlinear systems arising from incompressible Navier–Stokes equations. When the Reynolds number is relatively high, these systems often involve millions of degrees of freedom (DOFs), and the nonlinear systems are difficult to converge, partially due to the strong asymmetry of the system and the saddle‐point structure. In this work, we propose to alleviate these issues by leveraging a multilevel ILU preconditioner calledHILUCSI, which is particularly effective for saddle‐point problems and can enable robust and rapid convergence of the inner iterations in Newton–GMRES. We further use Picard iterations with the Oseen systems to hot‐start Newton–GMRES to achieve global convergence, also preconditioned using HILUCSI. To further improve efficiency and robustness, we use the Oseen operators as physics‐based sparsifiers when building preconditioners for Newton iterations and introduce adaptive refactorization and iterative refinement in HILUCSI. We refer to the resulting preconditioned hybrid Newton–GMRES asHILUNG. We demonstrate the effectiveness of HILUNG by solving the standard 2D driven‐cavity problem with Re 5000 and a 3D flow‐over‐cylinder problem with low viscosity. We compare HILUNG with some state‐of‐the‐art customized preconditioners for INS, including two variants of augmented Lagrangian preconditioners and two physics‐based preconditioners, as well as some general‐purpose approximate‐factorization techniques. Our comparison shows that HILUNG is much more robust for solving high‐Re problems and it is also more efficient in both memory and runtime for moderate‐Re problems.
Forecasting the volatility of agricultural commodity futures: The role of co‐volatility and oil volatility
Authors: Marfatia Hardik A. , Ji Qiang , Luo Jiawen 
Published: August 2021

AbstractWe forecast the realized volatilities of China's agricultural commodity futures (corn, cotton, palm, wheat, and soybean) using a set of multivariate heterogeneous autoregressive (MHAR) models. We consider different error structures to capture the co‐movement of volatility (co‐volatility) between commodity futures to obtain out‐of‐sample forecasts of the realized volatilities of agricultural commodity futures at daily, weekly, and monthly forecast horizons. We also consider global oil volatility as an additional exogenous predictor and assess forecast precision based on both statistical and economic value measures. The results show that the MHAR model with a co‐volatility error structure is superior in predicting the volatility of commodity futures. The most accurate predictions are of corn, cotton, and wheat futures volatility. Interestingly, for all the commodities, the forecasting accuracy noticeably improves as the forecast horizon increases. However, from an investment perspective, the highest economic value is gained from medium‐horizon forecasts, and the economic value of forecasts is highest for less risk‐averse investors.