bluuebunny/crossref_metadata_2025_split huggingface dataset:
A two-dimensional Fourier transform electron-spin resonance (ESR) study of nuclear modulation and spin relaxation in irradiated malonic acid
Authors: Lee Sanghyuk , Patyal Baldev R. , Freed Jack H. 
Published: July 2002

Nuclear modulation in electron-spin-echo spectroscopy is conventionally studied by one-dimensional electron-spin-echo envelope modulation (1D-ESEEM). Two-dimensional Fourier transform electron-spin resonance (2D-FTESR) studies of nuclear modulation have the promise of enhancing the spectral resolution and clarifying the key details of the relaxation processes. We present a 2D-FTESR study on single proton nuclear modulation from γ-irradiated malonic acid single crystals to test the validity of the Gamliel–Freed theory and to assess the value of the new methods. The two pulse spin-echo correlation spectroscopy (SECSY) spectra as a function of orientation of the single crystal show very good agreement with the Gamliel–Freed theory extended to the general case of nonaxially symmetric hyperfine interaction. It is very simply affected by spin relaxation, such that relative intensities are essentially unaffected. Thus SECSY-ESR can most reliably be utilized for studying nuclear modulation. Stimulated SECSY provides the simplest nuclear modulation patterns, which, however, do exhibit the suppression effect well known in three-pulse ESEEM studies. Two-dimensional electron–electron double resonance (2D-ELDOR) provides nuclear modulation patterns similar to that of SECSY-ESR, so the suppression effect is absent. Both three-pulse methods exhibit complex relaxation behavior which can affect relative intensities. This is a feature characteristic of three-pulse ESEEM, but is not well understood.
It is shown how the 2D-FTESR methods enable one to obtain the details of the complex spin relaxation, and in the process, obtain very good agreement between experiment and theory. 2D-ELDOR exhibits exchange cross peaks as well as coherence peaks from the nuclear modulation. It is shown how experiments, as a function of mixing time, enable one to separate the effects of the two. It is pointed out that such experiments are in the spirit of 3D spectroscopy. A new observation of the broadening of the 2D-ELDOR main peaks with an increase in mixing time is ascribed to the effects of solid-state dynamical processes that are slow on the ESR time scale and may thus be studied in ‘‘real time’’ in such experiments. The analysis of spin relaxation in this study is enabled by a full Liouville space derivation of the combined effects of nuclear modulation and spin relaxation in 2D-FTESR.
PGAAS: a prokaryotic genome assembly assistant system
Authors: Yu Zhou , Li Tao , Zhao Jindong , Luo Jingchu 
Published: July 2002

Abstract
Motivation: In order to accelerate the finishing phase of genome assembly, especially for the whole genome shotgun approach of prokaryotic species, we have developed a software package designated prokaryotic genome assembly assistant system (PGAAS). The approach upon which PGAAS is based is to confirm the order of contigs and fill gaps between contigs through peptide links obtained by searching each contig end with BLASTX against protein databases.
Results: We used the contig dataset of the cyanobacterium Synechococcus sp. strain PCC7002 (PCC7002), which was sequenced with six-fold coverage and assembled using the Phrap package. The subject database is the protein database of the cyanobacterium, Synechocystis sp. strain PCC6803 (PCC6803). We found more than 100 non-redundant peptide segments which can link at least 2 contigs. We tested one pair of linked contigs by sequencing and obtained satisfactory result. PGAAS provides a graphic user interface to show the bridge peptides and pier contigs. We integrated Primer3 into our package to design PCR primers at the adjacent ends of the pier contigs.
Availability: We tested PGAAS on a Linux (Redhat 6.2) PC machine. It is developed with free software (MySQL, PHP and Apache). The whole package is distributed freely and can be downloaded as UNIX compress file: ftp://ftp.cbi.pku.edu.cn/pub/software/unix/pgaas1.0.tar.gz. The package is being continually updated.
Contact: luojc@pku.edu.cn
* To whom correspondence should be addressed.
Exploring the conformational equilibrium of E. coli thioredoxin reductase: Characterization of two catalytically important states by ultrafast flavin fluorescence spectroscopy
Authors: Van Den Berg Petra A.W. , Mulrooney Scott B. , Gobets Bas , Van Stokkum Ivo H.M. , Van Hoek Arie , Williams Charles H. , Visser Antonie J.W.G. 
Published: July 2002

AbstractThe conformational dynamics of wild‐type Escherichia coli thioredoxin reductase (TrxR) and the mutant enzyme C138S were studied by ultrafast time‐resolved fluorescence of the flavin cofactor in combination with circular dichroism (both in the flavin fingerprint and far‐UV regions) and steady‐state fluorescence and absorption spectroscopy. The spectroscopic data show two conformational states of the enzyme (named FO and FR), of which the physical characteristics differ considerably. Ultrafast fluorescence lifetime measurements make it possible to distinguish between the two different populations: Dominant picosecond lifetimes of ∼1 ps (contribution 75%) and 7 ps (8%) are associated with the FO species in TrxR C138S. Long‐lived fluorescence with two time constants in the range of 0.2–1 ns (total contribution 17%) originates from enzyme molecules in the FR conformation. The near absence of fast lifetime components in oxidized wild‐type TrxR supports the idea of this enzyme being predominantly in the FR conformation. The emission spectrum of the FO conformation is blue‐shifted with respect to that of the FR conformation. Because of the large difference in fluorescence characteristics, fluorescence measurements on time scales longer than 100 ps are fully determined by the fraction of enzyme molecules in the FR conformation. Binding of the thiol reagent phenyl mercuric acetate to wild‐type enzyme and TrxR C138S stabilizes the enzymes in the FR conformation. Specific binding of the NADPH‐analog, AADP+, to the FR conformation resulted in dynamic fluorescence quenching in support of the multiple quenching sites model. Raising the temperature from 277K–323K resulted in a moderate shift to the FR conformation for TrxR C138S. High concentrations of the cosolvent glycerol triggered the domain rotation from the FO to the FR conformation.
Alternative type I and I′ turn conformations in the β8/β9 β‐hairpin of human acidic fibroblast growth factor
Authors: Kim Jaewon , Blaber Sachiko I. , Blaber Michael 
Published: July 2002

AbstractHuman acidic fibroblast growth factor (FGF‐1) has a β‐trefoil structure, one of the fundamental protein superfolds. The X‐ray crystal structures of wild‐type and various mutant forms of FGF‐1 have been solved in five different space groups: C2, C2221, P21 (four molecules/asu), P21 (three molecules/asu), and P212121. These structures reveal two characteristically different conformations for the β8/β9 β‐hairpin comprising residue positions 90–94. This region in the wild‐type FGF‐1 structure (P21, four molecules/asu), a his‐tagged His93→Gly mutant (P21, three molecules/asu) and a his‐tagged Asn106→Gly mutant (P212121) adopts a 3:5 β‐hairpin known as a type I (1–4) G1 β‐bulge (containing a type I turn). However, a his‐tagged form of wild‐type FGF‐1 (C2221) and a his‐tagged Leu44→Phe mutant (C2) adopt a 3:3 β‐hairpin (containing a type I′ turn) for this same region. A feature that distinguishes these two types of β‐hairpin structures is the number and location of side chain positions with eclipsed Cβ and main‐chain carbonyl oxygen groups (Ψ ≅ +60°). The effects of glycine mutations upon stability, at positions within the hairpin, have been used to identify the most likely structure in solution. Type I′ turns in the structural data bank are quite rare, and a survey of these turns reveals that a large percentage exhibit crystal contacts within 3.0 Å. This suggests that many of the type I′ turns in X‐ray structures may be adopted due to crystal packing effects.
Efficacy of melatonin in term neonatal models of perinatal hypoxia‐ischaemia
Authors: Pang Raymand , Han Hyun Jee , Meehan Christopher , Golay Xavier , Miller Suzanne L. , Robertson Nicola J. 
Published: April 2022

AbstractObjectiveNeonatal encephalopathy (NE) is an important cause of mortality and disability worldwide. Therapeutic hypothermia (HT) is an effective therapy, however not all babies benefit. Novel agents are urgently needed to improve outcomes. Melatonin in preclinical studies has promising neuroprotective properties. This meta‐analysis assessed the efficacy of melatonin in term animal models of NE on cerebral infarct size, neurobehavioural tests and cell death.MethodsA literature search was carried out using Embase, MEDLINE and Web of Science (31 May 2021). We identified 14 studies and performed a meta‐analysis with a random effects model using standardised mean difference (SMD) as the effect size. The risk of bias was assessed using the Systematic Review Centre for Laboratory animal Experimentation tool and publication bias was assessed with funnel plots, and adjusted using trim and fill analysis. Subgroup and meta‐regression analyses were performed to assess the effects of study design variables.ResultsWe observed significant reduction in brain infarct size (SMD −2.05, 95% CI [−2.93, −1.16]), improved neurobehavioural outcomes (SMD −0.86, 95% CI [−1.23, −0.53]) and reduction in cell death (SMD −0.60, 95% CI [−1.06, −0.14]) favouring treatment with melatonin. Neuroprotection was evident as a single therapy and combined with HT. Subgroup analysis showed greater efficacy with melatonin given before or immediately after injury and with ethanol excipients. The overall effect size remained robust even after adjustment for publication bias.InterpretationThese studies demonstrate a significant neuroprotective efficacy of melatonin in term neonatal models of hypoxia‐ischaemia, and suggest melatonin is a strong candidate for translation to clinical trials in babies with moderate–severe NE.
Integrating Additive Manufacturing Techniques to Improve Cell‐Based Implants for the Treatment of Type 1 Diabetes
Authors: Accolla Robert P. , Simmons Amberlyn M. , Stabler Cherie L. 
Published: April 2022

AbstractThe increasing global prevalence of endocrine diseases like type 1 diabetes mellitus (T1DM) elevates the need for cellular replacement approaches, which can potentially enhance therapeutic durability and outcomes. Central to any cell therapy is the design of delivery systems that support cell survival and integration. In T1DM, well‐established fabrication methods have created a wide range of implants, ranging from 3D macro‐scale scaffolds to nano‐scale coatings. These traditional methods, however, are often challenged by their inherent limitations in reproducible and discrete fabrication, particularly when scaling to the clinic. Additive manufacturing (AM) techniques provide a means to address these challenges by delivering improved control over construct geometry and microscale component placement. While still early in development in the context of T1DM cellular transplantation, the integration of AM approaches serves to improve nutrient material transport, vascularization efficiency, and the accuracy of cell, matrix, and local therapeutic placement. This review highlights current methods in T1DM cellular transplantation and the potential of AM approaches to overcome these limitations. In addition, emerging AM technologies and their broader application to cell‐based therapy are discussed.
The short form effort−reward imbalance: Measure of occupational stress for firefighters
Authors: Chin Dal Lae , Kyung MinJung , Li Jian , Phelps Stephanie , Hong OiSaeng 
Published: April 2022

AbstractPurposeThe original effort−reward imbalance (ERI) questionnaire has been widely used as a measure of occupational stress. The need for brief measurement of psychosocial stress at work has risen. This study examined the psychometric properties of a 16‐item short form ERI (S‐ERI) questionnaire.MethodsA cross‐sectional study was conducted with a convenience sample of 247 career firefighters in the United States. An internet‐based survey contained the S‐ERI questionnaire, and assessed perceived health, demographics, and work characteristics. Internal consistency was tested by item‐total correlation and Cronbach's α coefficients. Factorial validity was assessed by confirmatory factor analysis (CFA), and criterion validity was examined by testing the S‐ERI's association with perceived health, controlling for other factors.ResultsThe study participants were primarily young and mid‐aged White males (mean age = 42 years, 75% White non‐Hispanic, 93% males). The S‐ERI questionnaire showed satisfactory internal consistency, with Cronbach α coefficients above 0.80 for all three scales: effort 0.82, reward 0.83, and overcommitment 0.81. CFA showed all the S‐ERI components had a good fit (goodness‐of‐fit index = 0.99, comparative fit index = 0.92, root mean square error of approximation = 0.06). In terms of criterion validity, significantly increased odds ratios (ORs) for perceived health (those indicating they were less healthy) were found in firefighters in the lowest tertile of reward (OR = 7.06, 95% confidence interval [CI]: 2.86−17.43), and highest tertile of overcommitment (OR = 2.29, 95% CI: 1.00−5.22), after controlling for other factors.ConclusionThe S‐ERI questionnaire is a reliable and valid measure to assess occupational stress. We recommend the use of S‐ERI as a measure of occupational stress when initiating efforts to improve firefighters' wellness.
Heavy Atom‐Free, Mitochondria‐Targeted, and Activatable Photosensitizers for Photodynamic Therapy with Real‐Time In‐Situ Therapeutic Monitoring
Authors: Miao Junfeng , Huo Yingying , Yao Guangxiao , Feng Yu , Weng Jiajin , Zhao Wei , Guo Wei 
Published: April 2022

AbstractBased on spin‐orbit charge transfer intersystem crossing mechanism, two heavy‐atom‐free photosensitizers (PSs) BDP1/BDP2 with absorption maxima at 506 nm/660 nm were constructed for photodynamic therapy (PDT). The long triplet state lifetimes and large singlet oxygen quantum yields, coupled with the mitochondria‐targeted feature, made them highly phototoxic toward cancer cells. Moreover, the PDT‐promoted cell apoptosis could be monitored by an obvious fluorescence off‐on response of the two PSs due to the concomitant activation of extensive mitophagy, thus facilitating timely therapeutic feedback to avoid under‐ or over‐treatment. Importantly, such design allows the activatable PSs Glu‐BDP1/Glu‐BDP2 to be fabricated by attaching γ‐glutamyl, a substrate of γ‐glutamyltranspeptidase, to the alkoxyaniline unit of BDP1/BDP2, and their ability in either selectively killing cancer cells over normal cells or in ablating implanted tumour without damage to healthy tissue was demonstrated.
Well‐Controlled Living Polymerization of Phenylacetylenes in Water: Synthesis of Water‐Soluble Stereoregular Telechelic Poly(phenylacetylene)s
Authors: Echizen Kensuke , Taniguchi Tsuyoshi , Nishimura Tatsuya , Maeda Katsuhiro 
Published: April 2022

AbstractWell‐controlled living polymerization of water‐soluble phenylacetylene derivatives in water was achieved for the first time using a multicomponent catalytic system consisting of [Rh(nbd)Cl]2, an aryl boronic acid, diphenylacetylene having carboxy groups, a tetraalkylammonium hydroxide, and a water‐soluble triphenylphosphine. This catalytic system enables a direct synthesis of various water‐soluble cis‐stereoregular poly(phenylacetylene)s having a narrow molecular weight distribution, the molecular weight of which can be controlled by the initial feed ratio of the monomer to the catalyst. Moreover, the syntheses of water‐soluble telechelic poly(phenylacetylene)s having various functional groups at both chain ends as well as a water‐soluble block copolymer were achieved.
Controlled Tetradeuteration of Straight‐Chain Fatty Acids: Synthesis, Application, and Insight into the Metabolism of Oxidized Linoleic Acid
Authors: Watanabe Ayako , Hama Kotaro , Watanabe Kohei , Fujiwara Yuko , Yokoyama Kazuaki , Murata Shigeo , Takita Ryo 
Published: April 2022

AbstractWe describe a concise and reliable protocol for the precisely controlled tetradeuteration of straight‐chain fatty acids (FAs) at the α‐ and β‐positions that is generally applicable to a variety of FAs, including trans‐FAs, polyunsaturated FAs (PUFAs), and their oxidized derivatives. The precisely controlled introduction of four deuterium atoms into the FAs enables their persistent and quantitative tracking by LC‐MS/MS analysis based on their molecular structures. In addition, the phosphatidylcholine (PC) species prepared from the tetradeuterated FAs thus obtained give a diagnostic peak, namely, a phosphocholine fragment that contains deuterium, in the LC‐MS/MS analysis. With these features, the metabolism of a representative oxidized linoleic acid, that is, hydroxyoctadecadienoic acid (HODE), was investigated, leading to the identification of acyltransferases that transfer the acyl moiety derived from HODE to lysophosphatidylcholine.
Lattice‐Confined Single‐Atom Fe1Sx on Mesoporous TiO2 for Boosting Ambient Electrocatalytic N2 Reduction Reaction
Authors: Chen Jiayin , Kang Yikun , Zhang Wei , Zhang Zhenghao , Chen Yan , Yang Yi , Duan Linlin , Li Yefei , Li Wei 
Published: April 2022

AbstractMimicking natural nitrogenase to create highly efficient single‐atom catalysts (SACs) for ambient N2 fixation is highly desired, but still challenging. Herein, S‐coordinated Fe SACs on mesoporous TiO2 have been constructed by a lattice‐confined strategy. The extended X‐ray absorption fine structure and X‐ray photoelectron spectroscopy spectra demonstrate that Fe atoms are anchored in TiO2 lattice via the FeS2O2 coordination configuration. Theoretical calculations reveal that FeS2O2 sites are the active centers for electrocatalytic nitrogen reduction reaction (NRR). Moreover, the finite element analysis shows that confinement of opened and ordered mesopores can facilitate the mass transport and offer an enlarged active surface area for NRR. As a result, this catalyst delivers a favorable NH3 yield rate of 18.3 μg h−1 mgcat.−1 with a high Faradaic efficiency of 17.3 % at −0.20 V versus a reversible hydrogen electrode. Most importantly, this lattice‐confined strategy is universal and can also be applied to Ni1Sx@TiO2, Co1Sx@TiO2, Mo1Sx@TiO2, and Cu1Sx@TiO2 SACs. Our study provides new hints for the design and biomimetic synthesis of highly efficient NRR electrocatalysts.
Development of fluorinated nicotinonitriles and fused candidates as antimicrobial, antibiofilm, and enzyme inhibitors
Authors: Ibrahim Mona H. , El Menofy Nagwan G. , El kiki Shereen M. , Sherbiny Farag F. , Ismail Magda M. F. 
Published: April 2022

AbstractThe antimicrobial assessments of two new series of nicotinonitriles and pyrido[2,3‐d]pyrimidines were performed using amoxicillin and nystatin as reference standards. Outstanding antifungal activities were achieved by some target compounds; for instance, compounds 7 and 9 displayed a minimal inhibitory concentration (MIC) value of 1.95 µg/ml toward Candida albicans, compound 11 showed a potent anti‐Rhizopus effect (MIC 1.95 µg/ml) and compound 14 elicited remarkable antifungal effects against both Aspergillis niger and C. albicans (MIC 1.95 µg/ml). However, pyrido[2,3‐d]pyrimidines 12, 14, and 16 showed moderate antibacterial activities against some gram‐negative bacteria. The antibiofilm results of these compounds against resistant strains of Proteus mirabilis were better than those of Pseudomonas aeruginosa. Docking studies of these hits at the DNA gyrase active site revealed affinity and docking scores comparable to that of the reference standards. Gyrase‐inhibitory activities revealed that 14 (IC50 = 0.31 µM) is the most potent hit as DNA gyrase A inhibitor; it exhibited 1.66‐fold the activity of ciprofloxacin (IC50 = 0.50 µM) and it was a 44.3 times more potent gyrase B inhibitor (IC50 = 0.04 µM) than novobiocin (IC50 = 1.77 µM). Regarding its antifungal activity, it displayed 0.78% of the fluconazole activity as a 14α‐demethylase inhibitor. The cytotoxicity of 12, 14, and 16 on human diploid lung fibroblasts (WI38 cells) ensured their safety. Moreover, they are orally bioavailable with no permeation of the blood–brain barrier.
The mediating mechanism of earnings management on the relationship between life cycle and financial reporting quality: Finding from MRA and fsQCA
Authors: Khuong Nguyen Vinh , Anh Le Huu Tuan 
Published: April 2022

AbstractThe study examined the relationship between organization life cycle (OLC) and financial reporting quality (FRQ) in the Vietnamese context with the mediating role of earnings management (EM). We used estimation OLS, fixed effects model, and other robustness tests to validate the results on a sample of 408 Vietnamese listed companies over the period 2010–2017. In addition, we compare the regression results with a recently established approach is, fuzzy‐set qualitative comparative analysis (fsQCA). The multiple regression analysis results suggest that firms with low profits or poor financial performance have low‐quality financial statements. On the other hand, when firms mature or have significant retained earnings, the quality of financial information improves and peaks. Besides, throughout the OLC, real earnings management behaviors are less likely to be used than accruals earnings management. Finally, because of the mediating effect of EM, the influence of OLC on FRQ is increased. The fsQCA findings indicate complex configurations between OLC, EM and other controls factors to the outcome of FRQ. This research contributes empirical evidence to the scientific literature on accounting and corporate governance. Next, the main contribution of our study is the examination of mediating role of EM on OLC‐FRQ association through both regression analysis and the fsQCA approach. Additionally, we conducted this study in Vietnam, where the legal framework in protecting the investors is still not complete; this will significantly contribute to the literature overview of OLC and FRQ.
Impact of physical exercise in advanced‐stage cancer patients: Systematic review and meta‐analysis
Authors: Rodríguez‐Cañamero Sergio , Cobo‐Cuenca Ana Isabel , Carmona‐Torres Juan Manuel , Pozuelo‐Carrascosa Diana Patricia , Santacruz‐Salas Esmeralda , Rabanales‐Sotos Joseba Aingerun , Cuesta‐Mateos Tatiana , Laredo‐Aguilera José Alberto 
Published: April 2022

AbstractHealth professionals predict that the number of people who will suffer and die from oncological diseases will continue to increase. It is vitally important to provide comprehensive care to these patients and prescribe physical exercise programs as adjuvant therapy. The objective of this systematic review was to determine the impact of physical exercise on advanced‐stage cancer patients. A literature search was performed in eight different databases. This search focused on randomized controlled trials (RCTs) published during the last 10 years. To assess the methodological quality of the sample of 15 RCTs finally obtained, the PEDro scale was used. Aerobic and strength training methods were used. The combination of both aerobic and strength training methods was the most frequently reported. Likewise, different physical and psychological variables were recorded, from which improvements were seen in fatigue, independence, quality of life and sleep, among others. The participation in physical exercise programs by advanced‐stage cancer patients has a positive impact on health. Providing these programs serves as adjuvant therapy, facilitating the comprehensive care of patients. Similarly, aerobic, strength or mixed training programs increase the muscle mass of patients and therefore reduce hypotonia, the main side effect during the advanced‐stages of cancer.