bluuebunny/crossref_metadata_2025_split huggingface dataset:
Normal Pressure Hydrocephalus Associated with Alzheimer's Disease
Authors: Müller‐Schmitz Katharina , Krasavina‐Loka Natalia , Yardimci Tugba , Lipka Tim , Kolman Aschwin G. J. , Robbers Sabine , Menge Til , Kujovic Milenko , Seitz Rüdiger J. 
Published: July 2020

ObjectiveThe aim was to investigate whether neurodegenerative biomarkers in cerebrospinal fluid (CSF) differentiate patients with suspected normal pressure hydrocephalus (NPH) who respond to CSF drainage from patients who do not respond.MethodsData from 62 consecutive patients who presented with magnetic resonance imaging changes indicative of NPH were studied with regard to cognitive and gait functions before and after drainage of 40–50ml of CSF. Additionally, S100 protein, neuron‐specific enolase, β‐amyloid protein, tau protein and phospho‐tau were determined in CSF. Statistical analyses were carried out with ANOVA and multiple linear regression.ResultsPatients with CSF constellations typical for Alzheimer's disease (n = 28) improved significantly in cognitive and gait‐related functions after CSF drainage. In contrast, those patients without a CSF constellation typical for Alzheimer's disease (n = 34) did not improve in cognitive and gait‐related functions after CSF drainage. In addition, positive CSF biomarkers for Alzheimer's disease predicted these improvements.InterpretationOur data suggest an association between Alzheimer's disease and NPH changes, supporting the recently suggested dichotomy of a neurodegenerative NPH and a true idiopathic NPH, with the latter appearing to be rare. ANN NEUROL 2020;88:703–711
Saturated Bioisosteres of ortho‐Substituted Benzenes
Authors: Denisenko Aleksandr , Garbuz Pavel , Shishkina Svetlana V. , Voloshchuk Nataliya M. , Mykhailiuk Pavel K. 
Published: July 2020

AbstractSaturated bioisosteres of ortho‐disubstituted benzenes (bicyclo[2.1.1]hexanes) were synthesized, characterized and validated. These cores were incorporated into the bioactive compounds Valsartan, Boskalid and Fluxapyroxad instead of the benzene ring. The saturated analogues showed a similar level of antifungal activity compared to that of Boskalid and Fluxapyroxad.
Quinolactacin Biosynthesis Involves Non‐Ribosomal‐Peptide‐Synthetase‐Catalyzed Dieckmann Condensation to Form the Quinolone‐γ‐lactam Hybrid
Authors: Zhao Fanglong , Liu Zhiwen , Yang Shuyuan , Ding Ning , Gao Xue 
Published: July 2020

AbstractQuinolactacins are novel fungal alkaloids that feature a quinolone‐γ‐lactam hybrid, which is a potential pharmacophore for the treatment of cancer and Alzheimer's disease. Herein, we report the identification of the quinolactacin A2 biosynthetic gene cluster and elucidate the enzymatic basis for the formation of the quinolone‐γ‐lactam structure. We reveal an unusual β‐keto acid (N‐methyl‐2‐aminobenzoylacetate) precursor that is derived from the primary metabolite l‐kynurenine via methylation, oxidative decarboxylation, and amide hydrolysis reactions. In vitro assays reveal two single‐module non‐ribosomal peptide synthetases (NRPs) that incorporate the β‐keto acid and l‐isoleucine, followed by Dieckmann condensation, to form the quinolone‐γ‐lactam. Notably, the bioconversion from l‐kynurenine to the β‐keto acid is a unique strategy employed by nature to decouple R*‐domain‐containing NRPS from the polyketide synthase (PKS) machinery, expanding the paradigm for the biosynthesis of quinolone‐γ‐lactam natural products via Dieckmann condensation.
Acid–Base Free Main Group Carbonyl Analogues
Authors: Loh Ying Kai , Aldridge Simon 
Published: July 2020

AbstractMain group carbonyl analogues (R2E=O) derived from p‐block elements (E=groups 13 to 15) have long been considered as elusive species. Previously, employment of chemical tricks such as acid‐ and base‐stabilization protocols granted access to these transient species in their masked forms. However, electronic and steric effects inevitably perturb their chemical reactivity and distinguish them from classical carbonyl compounds. A new era was marked by the recent isolation of acid–base free main group carbonyl analogues, ranging from a lighter boracarbonyl to the heavier silacarbonyls, phosphacarbonyls and a germacarbonyl. Most importantly, their unperturbed nature elicits exciting new chemistry, spanning the vista from classical organic carbonyl‐type reactions to transition metal‐like oxide ion transfer chemistry. In this Review, we survey the strategies used for the isolation of such systems and document their emerging reactivity profiles, with a view to providing fundamental comparisons both with carbon and transition metal oxo species. This highlights the emerging opportunities for exciting “crossover” reactivity offered by these derivatives of the p‐block elements.
Evolution of the Diels–Alder Reaction Mechanism since the 1930s: Woodward, Houk with Woodward, and the Influence of Computational Chemistry on Understanding Cycloadditions
Authors: Houk Kendall N. , Liu Fang , Yang Zhongyue , Seeman Jeffrey I. 
Published: July 2020

AbstractThis review article describes the evolution of Woodward's mechanistic thinking, beginning in the late 1930s and early 1940s with his proposal of a charge‐transfer mechanism for the Diels–Alder reaction, eventually leading to the Woodward–Katz two‐stage concerted mechanism in 1959, and then to its mechanistic solution in terms of orbital symmetry control. Houk′s research in the Woodward labs, testing the predictions of this theory, is described. Subsequent modern calculations with quantum mechanics and molecular dynamics simulations have shown that Woodward indeed had perfectly described not only the cyclopentadiene dimerization mechanism, but a new class of transition states now known as ambimodal or bis‐pericyclic transition states. In recent years, the Houk group has found that ambimodal reactions are operative in the [6+4] cycloaddition. Molecular dynamics simulations of many Diels–Alder and ambimodal cycloadditions provide a time‐resolved picture of how these reactions occur. Lastly, Roald Hoffmann provides a Coda in which he describes his joy in “being taken along the journey” of the cycloaddition story from Woodward's youth to today's trajectory simulations.
Photo‐Induced Ruthenium‐Catalyzed C−H Arylations at Ambient Temperature
Authors: Korvorapun Korkit , Struwe Julia , Kuniyil Rositha , Zangarelli Agnese , Casnati Anna , Waeterschoot Marjo , Ackermann Lutz 
Published: July 2020

AbstractAmbient temperature ruthenium‐catalyzed C−H arylations were accomplished by visible light without additional photocatalysts. The robustness of the ruthenium‐catalyzed C−H functionalization protocol was reflected by a broad range of sensitive functional groups and synthetically useful pyrazoles, triazoles and sensitive nucleosides and nucleotides, as well as multifold C−H functionalizations. Biscyclometalated ruthenium complexes were identified as the key intermediates in the photoredox ruthenium catalysis by detailed computational and experimental mechanistic analysis. Calculations suggested that the in situ formed photoactive ruthenium species preferably underwent an inner‐sphere electron transfer.
Aggregation‐Induced Emission (AIE): A Historical Perspective
Authors: Würthner Frank 
Published: July 2020

AbstractAggregation‐induced emission (AIE) has attracted considerable interest over the last twenty years. In contrast to the large number of available reviews focusing specifically on AIE, this Essay discusses the AIE phenomenon from a broader perspective, with an emphasis on early observations related to AIE made long before the term was coined. Illustrative examples are highlighted from the 20th century where fluorescence enhancement upon rigidification of dyes in viscous or solid environments or J‐aggregate formation was studied. It is shown that these examples already include typical AIE luminogens such as tetraphenylethylene (TPE) as well as stilbenes and oligo‐ or polyphenylenevinylenes and ‐ethynylenes, which became important fluorescent solid‐state materials in OLED research in the 1990s. Further examples include cyanine dyes such as thiazole orange (TO) or its dimers (TOTOs), which have been widely applied as molecular probes in nucleic acid research. The up to 10 000‐fold fluorescence enhancement of such dyes upon intercalation into double‐stranded DNA, attributable to the restricted intramolecular motion (RIM) concept, afforded commercial products for bioimaging and fluorescence sensing applications already in the early 1990s.
Cobalt Nanoparticles‐Catalyzed Widely Applicable Successive C−C Bond Cleavage in Alcohols to Access Esters
Authors: Luo Huihui , Wang Lianyue , Shang Sensen , Li Guosong , Lv Ying , Gao Shuang , Dai Wen 
Published: July 2020

AbstractSelective cleavage and functionalization of C−C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C−C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C−C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long‐chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent −(C−C)n− bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C−C bonds to achieve excellent catalytic activity, while the presence of Co‐Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
A Generalizable and Noncovalent Strategy for Interfacing Aptamers with a Microelectrode for the Selective Sensing of Neurotransmitters In Vivo
Authors: Hou Hanfeng , Jin Ying , Wei Huan , Ji Wenliang , Xue Yifei , Hu Jingbo , Zhang Meining , Jiang Ying , Mao Lanqun 
Published: July 2020

AbstractThe selective sensing of neurochemicals is essential for understanding the chemical basis of brain function and pathology. Interfacing the excellent recognition features of aptamers with in vivo compatible carbon fiber microelectrode (CFE)‐based electroanalytical systems offers a plausible means to achieve this end. However, this is challenging in terms of coupling chemistry, stability, and versatility. Here, we present a new interfacial functionalization strategy based on the assembly of aptamer cholesterol amphiphiles (aptCAs) on the alkyl chain‐functionalized CFE. The noncovalent cholesterol‐alkyl chain interactions effectively immobilize aptamers onto the CFE surface, allowing the generation of a highly selective system for probing neurochemical dynamics in living systems and opening up a vast array of new opportunities for designing in vivo sensors for exploring brain chemistry.
Integrating the principles of transference‐focused psychotherapy with psychiatric consultation for patients admitted to a general hospital: A clinical application of a psychotherapeutic tool
Authors: Moscara Maria , Bergonzini Elisa 
Published: July 2020

AbstractIn the general hospital (GH), medical staff can find it difficult to establish collaborative relationships with patients exhibiting challenging behavior or personalities. Furthermore many of these patients need complex medical diagnoses and treatments. This paper illustrates an application of the principles of transference‐focused psychotherapy (TFP) in a psychiatric consultation for a patient with cardiac disease and poor adherence to medical recommendations. Among the principles of TFP illustrated are technical neutrality and the three channels of communication – verbal communication, nonverbal communication and countertransference. In addition, the paper shows the use of catamnesis, or the patient's report of their medical history and prior medical treatments. TFP principles allow the psychiatrist to assess the structure of the patient's personality and to help the medical staff to manage their relationship with the patient. TFP principles can be useful tools for psychiatrists working in consultation – liaison services in a general hospital.
Basic Amino Acid Conjugates of 1,2‐Diselenan‐4‐amine with Protein Disulfide Isomerase‐like Functions as a Manipulator of Protein Quality Control
Authors: Tsukagoshi Shunsuke , Mikami Rumi , Arai Kenta 
Published: July 2020

AbstractProtein disulfide isomerase (PDI) can assist immature proteins to correctly fold by controlling cysteinyl disulfide (SS)‐relating reactions (i. e., SS‐formation, SS‐cleavage, and SS‐isomerization). PDI controls protein quality by suppressing protein aggregation, as well as functions as an oxidative folding catalyst. Following the amino acid sequence of the active center in PDI, basic amino acid conjugates of 1,2‐diselenan‐4‐amine (1), which show oxidoreductase‐ and isomerase‐like activities for SS‐relating reactions, were designed as a novel PDI model compound. By conjugating the amino acids, the diselenide reduction potential of compound 1 was significantly increased, causing improvement of the catalytic activities for all SS‐relating reactions. Furthermore, these compounds, especially histidine‐conjugated one, remarkably suppressed protein aggregation even at low concertation (0.3 mM∼). Thus, it was demonstrated that the conjugation of basic amino acids into 1 simultaneously achieves the enhancement of the redox reactivity and the capability to suppress protein aggregation.
Recent Progress of Hybrid Optical Probes for Neural Membrane Potential Imaging
Authors: Liu Yongyang , Lu Yaxin , Chen Guangcun , Wang Qiangbin 
Published: July 2020

AbstractThe neural membrane potential of nerve cells is the basis of neural activity production, which controls advanced brain activities such as memory, emotion, and learning. In the past decades, optical voltage indicator has emerged as a promising tool to decode neural activities with high‐fidelity and excellent spatiotemporal resolution. In particular, the hybrid optical probes can combine the advantageous photophysical properties of different components such as voltage‐sensitive molecules, highly fluorescent fluorophores, membrane‐targeting tags, and optogenetic materials, thus showing numerous advantages in improving the photoluminescence intensity, voltage sensitivity, photostability, and cell specificity of probes. In this review, the current state‐of‐the‐art hybrid probes are highlighted, that are designed by using fluorescent proteins, organic dyes, and fluorescent nanoprobes as the fluorophores, respectively. Then, the design strategies, voltage‐sensing mechanisms and the in vitro and in vivo neural activity imaging applications of the hybrid probes are summarized. Finally, based on the current achievements of voltage imaging studies, the challenges and prospects for design and application of hybrid optical probes in the future are presented.
A virtual ELISA to quantitate COVID‐19 antibodies in patient serum
Authors: Simpson Kevin , Jakubowski Henry V. 
Published: July 2020

AbstractEnzyme‐linked immunosorbent assays (ELISAs) are used widely in biotechnology, pharmaceutical, and clinical medicine labs. At the same time, they appear to be underrepresented in chemistry and biochemistry curricula, even though their sensitivity, selectivity, and ease of use would argue for their widespread use. We describe here an online ELISA activity suitable for stand‐alone use or in conjunction with an actual wet lab ELISA. Specifically, we offer real and mock data for a hypothetical ELISA to detect plasma antibodies to COVID‐19 in infected patients who have had the disease. Much of the activity focuses on chemical and mathematical models to fit ELISA or any macromolecule/ligand binding data, a skill that addresses perhaps the most relevant and difficult learning goal of an ELISA experiment.
Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta‐analysis based on randomized controlled trials
Authors: Zhang Ning , Zhang Yanan , Li Menglin , Wang Weiguang , Liu Zhenzhu , Xi Chongcheng , Huang Xunying , Liu Jintao , Huang Junwei , Tian Dong , Mu Jie , Liao Xing , Zhai Shuangqing 
Published: July 2020

AbstractBackgroundProbiotics seems to play a beneficial role in stressed populations; thus, a systematic review and meta‐analysis to assess the effects of probiotics on stress in healthy subjects were conducted.MethodsRandomized controlled trials on the effects of probiotics on stress in healthy subjects were retrieved from five databases. The effects of probiotics on subjective stress level, stress‐related subthreshold anxiety/depression level, cortisol level, and adverse reactions were analyzed. Separate subgroup analyses were conducted on single‐strain probiotics versus multi‐strain probiotics, and short‐term administration versus long‐term administration.ResultsSeven studies were included, involving a total of 1,146 subjects. All the studies were rated as low or moderate risk of bias. Our research found that probiotic administration can generally reduce the subjective stress level of healthy volunteers and may improve their stress‐related subthreshold anxiety/depression level, but no significant effect was observed in the subgroup analysis. The effect of probiotics on cortisol level was not significant. Adverse reactions were reported in only one of seven studies, but left undescribed.ConclusionCurrent evidence suggests that probiotics can reduce subjective stress level in healthy volunteers and may alleviate stress‐related subthreshold anxiety/depression level, without significant effect on cortisol level, and there is not enough support to draw conclusions about adverse effects; thus, more reliable evidence from clinical trials is needed.
Inverse liquid‐solid chromatography to evaluate drug interactions with organosilane‐modified polydimethylsiloxane for use in body‐on‐a‐chip systems
Authors: Schnepper Mark , Roles Jeff , Hickman James J. 
Published: July 2020

AbstractBody‐on‐a‐chip and organ‐on‐a‐chip systems utilize polydimethylsiloxane (PDMS) because of the relative suitability of the material for fabrication of microfluidic channels and chambers used in these devices. However, hydrophobic molecules, especially therapeutic compounds, tend to adsorb to PDMS, which may distort the dose–response curves that feed into the pharmacokinetic/pharmacodynamic models used to translate preclinical data into predictions of clinical outcomes. Surface modification by organosilanes is one method being explored to modify PDMS, but the effect of organosilanes on drug adsorption isotherms is not well characterized. We utilized Inverse Liquid‐Solid Chromatography to characterize the adsorption parameters of the drugs acetaminophen, diclofenac, and verapamil with native PDMS and organosilane‐modified (fluoropolymer (13F) and polyethylene glycol) PDMS surfaces, to correlate the modifications with changes in drug adsorption. It was determined that the organosilane modifications significantly changed the energy of adsorption of the test drug utilizing our methodology.
Electromagnetic education: Development of an interactive GUI for demonstrating wave polarization
Authors: Wong Shin Yun , Lim Soo Yong 
Published: July 2020

AbstractOver the years, we have seen rapid advances in technology that have contributed to the modern lifestyle. It is obvious that there is a strong correlation between technological advances and the quality of education that has been provided to students. It is fair to say that the current educational system is reasonably good, because it has successfully created a platform for innovation in science and technology. However, there seems to be a lack of integration of technology into the education system. The goal of this paper is to utilize technology to improve the quality of electromagnetics education. It documents the development of a MATLAB‐based graphical user interface to visualize plane wave polarization, electromagnetic wave propagation in two and three‐dimensions, plane wavefronts, and spherical wavefronts. The multiwindow app allows users to customize the wave parameters such as amplitude, frequency, phase shift, and attenuation constant. This interactive application does not aim to replace teachers and lecturers, but it serves to enhance the teaching process and to help students better understand the relevant concepts.
Development and Validation of HPLC Method for Determination of Sodium Copper Chlorophyllin – A Food Colorant and Its Application in Pharmacokinetic Study
Authors: Laddha Ankit P. , Nalawade Vivek V. , Gharpure Milind , Kulkarni Yogesh A. 
Published: July 2020

AbstractA simple, accurate, and precise bioanalytical method was developed and validated for the determination of pharmacokinetic parameters of sodium copper chlorophyllin, a USFDA approved food additive and colorant in rat plasma. The column used was Luna® C18 250×4.6 mm, 100 Å, having particle size 4.5 μm, and the mobile phase used was methanol (MeOH), and 10 mM ammonium acetate buffer in the ratio of 90 : 10, the flow rate was 1 ml/min, and the injection volume of 20 μL. The retention time of sodium copper chlorophyllin was obtained at 9 min. The method was found to be linear at the range of 0.50–8.00 μg mL−1.
Quantitative Elemental Analysis of a Single Cell by Using Inductively Coupled Plasma‐Mass Spectrometry in Fast Time‐Resolved Analysis Mode
Authors: Tanaka Yu‐ki , Iida Risako , Takada Shohei , Kubota Tetsuo , Yamanaka Michiko , Sugiyama Naoki , Abdelnour Yolande , Ogra Yasumitsu 
Published: July 2020

AbstractThe elemental composition of a single yeast, green alga, or red blood cell (RBC) was precisely determined by using inductively coupled plasma‐mass spectrometry (ICP‐MS) operating in fast time‐resolved analysis (TRA) mode. The technique is known as single‐cell (SC)‐ICP‐MS. Phosphorus, sulfur, magnesium, zinc, and iron were detected in the three types of cell. The elemental composition of yeast and green alga obtained by SC‐ICP‐MS was consistent with results obtained from conventional ICP‐MS measurements following acid digestion of the cells. Slight differences were found in the measured values between SC‐ICP‐MS and the conventional ICP‐MS results for RBC. However, the SC‐ICP‐MS results for S and Fe in RBC were closer to the estimated values for these elements that were calculated from the level of hemoglobin in RBCs. The data suggest that SC‐ICP‐MS is suitable for the analysis of various cell types, namely, fungus, plant, and animal cells.