bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distinctive functions of the two structural calcium atoms in bovine pancreatic deoxyribonuclease
Authors: Chen Ching‐Ying , Lu Shao‐Chun , Liao Ta‐Hsiu 
Published: July 2002

AbstractThe two amino acid residues, Asp 99 and Asp 201, involved in the coordination of the two calcium atoms in the X‐ray structure of bovine pancreatic (bp) DNase, were individually changed by site‐directed mutagenesis. The two altered proteins, brDNase(D99A) and brDNase(D201A) were expressed in Escherichia coli and purified by anion exchange chromatography. Equilibrium dialysis showed that mutation destroyed one Ca2+‐binding site each in brDNase(D99A) and brDNase(D201A). Compared with bpDNase, the Vmax value for brDNase(D99A) remained unchanged and that for brDNase(D201A) was decreased, whereas the Km values for the two variants were increased two‐ to threefold when the DNA hydrolytic hyperchromicity assay was used. Like bpDNase, brDNase(D99A) was able to make double scission on duplex DNA with Mg2+ plus Ca2+ and was effectively protected by Ca2+ from the trypsin inactivation. But under the same conditions, brDNase(D201A) lost the double‐scission ability and was not protected by Ca2+. Nevertheless, the two variant proteins retained the characteristics of the Ca2+‐induced conformational changes and the Ca2+ protection against the β‐mercaptoethanol disruption of the essential disulfide bond, suggesting that other weaker Ca2+‐binding sites not found in the X‐ray structure were responsible for these properties. Therefore, the two structural calcium atoms are not for maintaining the overall conformation of the active DNase, as it has been indicated in the X‐ray analysis, but rather play the role in the fine‐tuning of the DNase activity.
Crystal structure of a cyanobacterial phytochrome response regulator
Authors: Im Young Jun , Rho Seong‐Hwan , Park Chung‐Mo , Yang Song‐Sook , Kang Jeong‐Gu , Lee Jae Young , Song Pill‐Soon , Eom Soo Hyun 
Published: July 2002

AbstractThe two‐component signal transduction pathway widespread in prokaryotes, fungi, molds, and some plants involves an elaborate phosphorelay cascade. Rcp1 is the phosphate receiver module in a two‐component system controlling the light response of cyanobacteria Synechocystis sp. via cyanobacterial phytochrome Cph1, which recognizes Rcp1 and transfers its phosphoryl group to an aspartate residue in response to light. Here we describe the crystal structure of Rcp1 refined to a crystallographic R‐factor of 18.8% at a resolution of 1.9 Å. The structure reveals a tightly associated homodimer with monomers comprised of doubly wound five‐stranded parallel β‐sheets forming a single‐domain protein homologous with the N‐terminal activator domain of other response regulators (e.g., chemotaxis protein CheY). The three‐dimensional structure of Rcp1 appears consistent with the conserved activation mechanism of phosphate receiver proteins, although in this case, the C‐terminal half of its regulatory domain, which undergoes structural changes upon phosphorylation, contributes to the dimerization interface. The involvement of the residues undergoing phosphorylation‐induced conformational changes at the dimeric interface suggests that dimerization of Rcp1 may be regulated by phosphorylation, which could affect the interaction of Rcp1 with downstream target molecules.
Modeling of the bacterial luciferase‐flavin mononucleotide complex combining flexible docking with structure‐activity data
Authors: Lin Leo Yen‐Cheng , Sulea Traian , Szittner Rose , Vassilyev Vladislav , Purisima Enrico O. , Meighen Edward A. 
Published: July 2002

AbstractAlthough the crystal structure of Vibrio harveyi luciferase has been elucidated, the binding sites for the flavin mononucleotide and fatty aldehyde substrates are still unknown. The determined location of the phosphate‐binding site close to Arg 107 on the α subunit of luciferase is supported here by point mutagenesis. This information, together with previous structure‐activity data for the length of the linker connecting the phosphate group to the isoalloxazine ring represent important characteristics of the luciferase‐bound conformation of the flavin mononucleotide. A model of the luciferase–flavin complex is developed here using flexible docking supplemented by these structural constraints. The location of the phosphate moiety was used as the anchor in a flexible docking procedure performed by conformation search by using the Monte Carlo minimization approach. The resulting databases of energy‐ranked feasible conformations of the luciferase complexes with flavin mononucleotide, ω‐phosphopentylflavin, ω‐phosphobutylflavin, and ω‐phosphopropylflavin were filtered according to the structure‐activity profile of these analogs. A unique model was sought not only on energetic criteria but also on the geometric requirement that the isoalloxazine ring of the active flavin analogs must assume a common orientation in the luciferase‐binding site, an orientation that is also inaccessible to the inactive flavin analog. The resulting model of the bacterial luciferase–flavin mononucleotide complex is consistent with the experimental data available in the literature. Specifically, the isoalloxazine ring of the flavin mononucleotide interacts with the Ala 74–Ala 75 cis‐peptide bond as well as with the Cys 106 side chain in the α subunit of luciferase. The model of the binary complex reveals a distinct cavity suitable for aldehyde binding adjacent to the isoalloxazine ring and flanked by other key residues (His 44 and Trp 250) implicated in the active site.
Transthyretin slowly exchanges subunits under physiological conditions: A convenient chromatographic method to study subunit exchange in oligomeric proteins
Authors: Schneider Frank , Hammarström Per , Kelly Jeffery W. 
Published: July 2002

AbstractTransthyretin (TTR) subunits were labeled with a charge‐modifying tag to evaluate the possibility of subunit exchange between tetramers under physiological conditions. Starting with a mixture of two TTR homotetramers, one having all subunits tagged at the N termini and the other composed of untagged subunits, heterotetramer formation as a function of time and temperature was evaluated using ion exchange chromatography. The data indicate that the subunit exchange can occur under native conditions at physiological pH in vitro, albeit slowly. Wild‐type TTR exchanges subunits on a timescale of days at 37°C and on a timescale of hours at 4°C. The familial amyloid polyneuropathy‐associated variant V30M exchanges subunits at the same rate as wild‐type TTR at 4°C but slower and less efficiently at 37°C. Small molecule tetramer stabilizers abolish TTR subunit exchange, supporting a dissociative mechanism.
Diffusion tensor imaging metrics in diagnosis of HTLV‐1‐associated myelopathy
Authors: Liberato de Matos Sheila N. F. , Ladeia‐Rocha Giovanna , Neto José Abraão Carneiro , de Oliveira Cassius J. V. , Neto César Araújo , Passos Lúcia , Oliveira‐Filho Jamary , Carvalho Edgar M. 
Published: March 2022

AbstractObjectiveIn the diagnosis of HTLV‐1‐associated myelopathy (HAM), while magnetic resonance imaging (MRI) is essential to exclude other diseases, its power is limited regarding HAM diagnosis, as only 30% of affected patients present with spinal cord atrophy. Diffusion tensor imaging (DTI) may enable the detection of damage in the white matter microstructure. Here, we quantitatively assess spinal cord damage using DTI and evaluate conventional MRI parameters of the spinal cord in HTLV‐1‐infected individuals.MethodsThis cross‐sectional study involved 33 HTLV‐1 carriers, 28 patients with definite‐HAM, and 11 seronegative healthy subjects (HS). Region‐of‐interest (ROI)‐based fractional anisotropy (FA) and mean diffusivity (MD) measurements were performed in the upper thoracic and lumbar regions of the spinal cord. Thoracic index was defined as 1/ (anteroposterior diameter × transverse diameter) measured at the fifth 5th vertebral level. Receiver operating characteristic (ROC) curve analysis was used to determine optimal cutoff FA, MD, and thoracic index values.ResultsSpinal cord atrophy was observed in 15 (53.6%) patients with definite‐HAM. The area under the ROC curve in the thoracic spinal cord was 0.824 (95% CI, 0.716–0.932), 0.839 (95% CI: 0.736–0.942), and 0.838 (95% CI: 0.728–0.949) for FA, MD, and the thoracic index, respectively. Lower FA and higher MD values were observed in the definite‐HAM group compared to HTLV‐1 carriers and HS at the T5 vertebral level (p < 0.01).InterpretationComplementary to conventional MRI, DTI analysis of the spinal cord and thoracic index determination can offer additional insight that may prove useful in the diagnosis of HAM.
The Core‐Shell Magnetic Mesoporous Microspheres Immobilized NHC‐Palladacycles: An Efficient and Recyclable Catalyst for Suzuki‐Miyaura Cross‐Coupling of Pharmaceutical Synthesis
Authors: Zuo Bin , Shao Han , Zheng Yan , Ma Yunhua , Li Wanfang , Huang Mingxian , Deng Qinyue 
Published: March 2022

AbstractThe core‐shell magnetic mesoporous microspheres immobilized NHC‐palladacycles (NHC=N‐heterocyclic carbene) catalyst with constrained aliphatic linker group (Fe3O4@mSiO2@NHC−Pd) were readily prepared by the well‐designed method, which showed higher palladium loading (0.20 mmol g−1) and higher catalytic activity than the non‐mesoporous catalysts (Fe3O4@SiO2@NHC−Pd) prepared by the same process in the Suzuki‐Miyaura cross‐coupling reactions of aryl chlorides and aryl boronic acids. Herein, Fe3O4@mSiO2@NHC−Pd could be used 12 times without significant activity loss, and no palladium leakage was detected in both the product and catalytic residue, highlighting the efficiency of our strategy for immobilizing the catalyst. Remarkably, this approach allows the synthesis of important drug intermediates 2‐aryl‐4‐aminoquinazolines and o‐tolylbenzonitrile (OTBN).
Recent Advances in the Functionalization of Terminal and Internal Alkynes
Authors: Ramani Arti , Desai Bhargav , Patel Monak , Naveen Togati 
Published: March 2022

AbstractAlkynes are one of the most fundamental and diverse functional groups utilized in organic synthesis. Over the past few years, the development of efficient synthetic methodologies for the functionalization of alkynes has been an active area of research. A plethora of alkyne functionalization reactions have been reported in the literature to construct functionalized alkynes and alkene scaffolds, which are important building blocks in many natural products, pharmaceuticals, and key intermediates in various synthetic transformations. In this review, we describe the most recent advances in the functionalization of alkynes with an emphasis on substrate scope, limitations, regioselectivity control and applications of these reactions. This review covers the literature from 2016 to 2021.
Dietary protein source matters for changes in inflammation measured by urinaryC‐reactiveprotein in rural polish women
Authors: Ban Hayley E. , Lee Katharine M. N. , Rogers‐LaVanne Mary P. , Zabłocka‐Słowińska Katarzyna , Galbarczyk Andrzej , Jasienska Grazyna , Clancy Kathryn B. H. 
Published: March 2022

AbstractObjectivesMultiple macronutrients have been shown to affect systemic inflammation, a well‐known predictor of chronic disease. Less often, varying sources of these macronutrients are examined. Different subsistence environments lead to varying access to protein sources which, combined with physical activity patterns, may lead to different relationships than among more typically studied sedentary, industrialized populations. This study hypothesizes an association between dietary protein intake and urinary C‐reactive protein (CRP) concentration in women from a rural, agrarian Polish community.Materials and MethodsWe assessed protein intake and their sources for 80 nonsmoking, premenopausal Polish women who were not pregnant, nursing, or on hormonal birth control during the study or within the previous 6 months. Each participant completed multiple 24‐hr dietary recalls during one menstrual cycle. Participants collected morning void urinary samples daily over one menstrual cycle for urinary CRP analysis. We analyzed relationships between plant and animal protein intake and CRP over the menstrual cycle by multiple linear regression.ResultsPlant protein in cereal foods was significantly positively associated with cycle‐average urinary CRP concentrations (p < 0.05) after controlling for body fat percent, total energy intake, and dietary fiber. Foods containing animal protein were not significantly associated with CRP.DiscussionContents of this population's main plant and animal protein sources differ from those of more commonly studied industrialized populations. Within the context of a population's typical diet, more emphasis may need to be placed on particular source of protein consumed, beyond plant versus animal, in order to understand relationships with CRP.
Association of Cardiac Biomarkers With Cardiovascular Outcomes in Patients With Psoriatic Arthritis and Psoriasis: A Longitudinal Cohort Study
Authors: Colaco Keith , Lee Ker‐Ai , Akhtari Shadi , Winer Raz , Welsh Paul , Sattar Naveed , McInnes Iain B. , Chandran Vinod , Harvey Paula , Cook Richard J. , Gladman Dafna D. , Piguet Vincent , Eder Lihi 
Published: March 2022

ObjectiveIn patients with psoriatic disease (PsD), we determined whether cardiac troponin I (cTnI) and N‐terminal pro–brain natriuretic peptide (NT‐proBNP) were associated with carotid plaque burden and the development of cardiovascular events independent of the Framingham Risk Score (FRS).MethodsAmong 1,000 patients with PsD, carotid total plaque area (TPA) was measured in 358 participants at baseline. Cardiac troponin I and NT‐proBNP were measured using automated clinical assays. The association between cardiac biomarkers and carotid atherosclerosis was assessed by multivariable regression after adjusting for cardiovascular risk factors. Improvement in the prediction of cardiovascular events beyond the FRS was tested using measures of risk discrimination and reclassification.ResultsIn univariate analyses, cTnI (β coefficient 0.52 [95% confidence interval (95% CI) 0.3, 0.74], P < 0.001) and NT‐proBNP (β coefficient 0.24 [95% CI 0.1, 0.39], P < 0.001) were associated with TPA. After adjusting for cardiovascular risk factors, the association remained statistically significant for cTnI (adjusted β coefficient 0.21 [95% CI 0, 0.41], P = 0.047) but not for NT‐proBNP (P = 0.21). Among the 1,000 patients with PsD assessed for cardiovascular risk prediction, 64 patients had incident cardiovascular events. When comparing a base model (with the FRS alone) to expanded models (with the FRS plus cardiac biomarkers), there was no improvement in predictive performance.ConclusionIn patients with PsD, cTnI may reflect the burden of atherosclerosis, independent of traditional cardiovascular risk factors. Cardiac troponin I and NT‐proBNP are associated with incident cardiovascular events independent of the FRS, but further study of their role in cardiovascular risk stratification is warranted.
Sliding mode control of switched systems: A geometric algebra approach
Authors: Sira Ramírez Hebertt , Aguilar‐Orduña Mario A. , Gómez‐León Brian C. 
Published: March 2022

AbstractGeometric algebra (GA) is proposed as a mathematical framework for revisiting fundamental aspects of sliding mode control (SMC) in nonlinear, switch‐controlled, single input systems. Sliding mode existence conditions, the switching policy, the invariance conditions, the associated equivalent control, and the characterization of ideal sliding dynamics, are all re‐examined using a geometric algebra (GA) standpoint. Two illustrative examples, from switched power electronics, are presented using the GA language.
Selection of Electrolyte Additive Quantities for Lithium‐Ion Batteries Using Bayesian Optimization
Authors: Hildenbrand Felix , Aupperle Felix , Stahl Gereon , Figgmeier Egbert , Sauer Dirk Uwe 
Published: March 2022

AbstractThe composition of the liquid electrolyte is a key factor in lifetime performance of lithium‐ion batteries. The selection and quantification of additives to the electrolyte is an active field of research. This study focuses on finding the optimal additive combination of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) for NMC622‐Graphite cells. The central goal of this work is to accelerate the experimental search in a large search area by using a Bayesian‐optimization algorithm to guide the search. Different measurements are used as target variable such as open‐circuit voltage gradient and coulombic efficiency. Consequentially, the capability of these measurements for accelerated lifetime prediction compared to conventional ageing tests by cycling is investigated. The search gathered and confirmed additive combinations with excellent performance after four iterations with a total of 15 additive combinations analyzed. The results of this study give insights into the interaction of VC and FEC with regard to ageing.
Swap and stop – Kinetochores play error correction with microtubules
Authors: Doodhi Harinath , Tanaka Tomoyuki U. 
Published: March 2022

AbstractCorrect chromosome segregation in mitosis relies on chromosome biorientation, in which sister kinetochores attach to microtubules from opposite spindle poles prior to segregation. To establish biorientation, aberrant kinetochore–microtubule interactions must be resolved through the error correction process. During error correction, kinetochore–microtubule interactions are exchanged (swapped) if aberrant, but the exchange must stop when biorientation is established. In this article, we discuss recent findings in budding yeast, which have revealed fundamental molecular mechanisms promoting this “swap and stop” process for error correction. Where relevant, we also compare the findings in budding yeast with mechanisms in higher eukaryotes. Evidence suggests that Aurora B kinase differentially regulates kinetochore attachments to the microtubule end and its lateral side and switches relative strength of the two kinetochore–microtubule attachment modes, which drives the exchange of kinetochore–microtubule interactions to resolve aberrant interactions. However, Aurora B kinase, recruited to centromeres and inner kinetochores, cannot reach its targets at kinetochore–microtubule interface when tension causes kinetochore stretching, which stops the kinetochore–microtubule exchange once biorientation is established.
The role of developmental assets in childhood career development
Authors: Kim Hyunhee , Carney JoLynn V. , Guo Xiuyan , Prescod Diandra J. 
Published: March 2022

AbstractThis study examined hope as a mediator between school connectedness and childhood career development. Participants included 456 elementary school students in Grades 4 through 6. The results of structural equation modeling supported the hypothesized mediation model, indicating that school connectedness leads to childhood career development both directly and indirectly via hope. The findings suggest that when children feel connected to school, they are likely to demonstrate a greater level of hope, which in turn leads to enhanced career development. The results of this study highlight the importance of developmental assets in promoting childhood career development and has important implications for counseling practice in school settings.
Realization of a Flexible Humidity Sensor Based on α‐In2Se3 Nanosheets
Authors: Zhang Xiaoya , Wu Yiwei , Wang Xinhao , Zhong Xiangli , Wang Jinbin , Zhang Yong 
Published: March 2022

AbstractHumidity sensors are widely used in domestic and industrial environments. The humidity sensing requires a sensor to be both flexible and stable. However, challenges still exist for the realization of efficient flexible humidity sensors. Herein, α‐In2Se3 nanosheet‐based humidity sensors both on PET and SiO2/Si substrates are fabricated. The humidity sensing behaviors are investigated in a wide relative humidity (RH) range from 11% RH to 97% RH at room temperature. Compared with a silicon‐based humidity sensor based on α‐In2Se3 nanosheets, the flexible humidity sensor based on α‐In2Se3 nanosheet exhibits higher sensitivity of 2.38×103%, shorter response and recovery time of 9 s and 13 s. Due to the lower activation energy of the flexible humidity sensor, the sensitivity of the flexible humidity sensor being 25 times higher than that of the silicon‐based humidity sensor. These results indicate that α‐In2Se3 nanosheet may be a potential humidity‐sensing material for fabricating humidity sensors with high performance, and the flexible humidity sensor based on α‐In2Se3 nanosheet has great potential in flexible wearable electronic devices.
A Supramolecular Antibiotic Switch for Plug‐and‐Play Antibacterial Regulation
Authors: Xu Shi‐Yuan , Peng Zi‐Ze , Wang Zi‐Xin , Li Wen‐Zhen , Ye Yu‐Yuan , Lin Xiao‐Wei , Ruan Yi‐Ru , Xiao Ju , Li Lingling , Wang Wenjing , Wang Xiao‐Qiang 
Published: March 2022

AbstractConstructing novel antibiotic switches is of great importance to fighting bacterial infections and reducing the public health threat caused by antibiotic abuse. In this work, a plug‐and‐play antibiotic switch based on the host‐guest interaction between berberine hydrochloride (BBR) and cucurbit[7]uril (CB[7]) is reported. BBR can be encapsulated in the cavity of CB[7] to form BBR@CB[7] with enhanced fluorescent emission and reduced antibacterial activity. And BBR can be released from BBR@CB[7] in the presence of other competitors, such as amantadine hydrochloride (ADA). The self‐assemble and disassemble ability of the supramolecular complex can be applied as facile plug‐and‐play antibiotic switch to “turn‐on” and “turn‐off” its antibacterial activity on demand. This work provides a simple, rapid, and efficient strategy for antibacterial regulation through supramolecular chemistry.
Electrodeposition of Amorphous Fe−P Shell on Co(OH)F Nanowire Arrays for Boosting Oxygen Evolution Electrocatalysis in Alkaline Media
Authors: Gu Yang , Meng Chuqian , Dong Shuyue , Zhu Hexin , Liu Qian , Luo Yonglan , Kong Qingquan , Li Tingshuai 
Published: March 2022

AbstractHigh‐performance earth‐abundant electrocatalysts for oxygen evolution reaction (OER) are highly desirable. In this report, we successfully synthesized amorphous Fe−P shell electrodeposited on Co(OH)F nanowire arrays supported on titanium mesh (Fe−P@Co(OH)F/TM) as an efficient catalyst for OER. Such catalyst exhibits excellent OER activity with a low overpotential of 267 mV to reach the geometrical current density of 10 mA cm−2 in 1.0 M KOH. In addition, it has good electrochemical durability to maintain its activity for at least 20 h.
High Proton Conductivity of 3D Graphene Oxide Intercalated with Aromatic Sulfonic Acids
Authors: Atiqur Rahman Mohammad , Islam Md. Saidul , Fukuda Mashahiro , Yagyu Junya , Feng Zhiqing , Sekine Yoshihiro , Lindoy Leonard F. , Ohyama Junya , Hayami Shinya 
Published: March 2022

AbstractThe development of efficient proton conductors that are capable of high power density, sufficient mechanical strength, and reduced gas permeability is challenging. Herein, we report the development of a series of aromatic sulfonic acid/graphene oxide hybrid membranes incorporating benzene sulfonic acid (BS), naphthalene sulfonic acid (NS), naphthalene disulfonic acid (DS) or pyrene sulfonic acid (PS) using a facile freeze dried method. For out‐of‐plane proton conductivity, the 3DGO‐BS and 3DGO‐NS yielded proton conductivities of 4.4×10−2 S cm−1 and 3.1×10−2 S cm−1, respectively; this represents a two‐times higher value than that which occurs for three dimensional graphene oxide (3DGO). Additionally, the respective prepared films as membranes in a proton exchange membrane fuel cell (PEMFC) show maximum power density of 98.76 mW cm−2 for 3DGO‐NS while it is 92.75 mW cm−2 for 3DGO‐BS which are close to double that obtained for 3DGO (50 mW cm−2).