bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hindered internal rotation and torsion–vibrational coupling in ortho-chlorotoluene (S1) and ortho-chlorotoluene+ (D)
Authors: Richard Erik C. , Walker Robert A. , Weisshaar James C. 
Published: July 2002

The techniques of resonant two-photon ionization (R2PI) and pulsed field ionization (PFI) were used to measure absorption spectra of ortho-chlorotoluene (S1, Ã 1A1) and of ortho-chlorotoluene+ (D0, X̃ 2A1; the cation ground state) for internally cold molecules in a pulsed nozzle expansion. The adiabatic ionization potential is 71 318±5 cm−1=8.8423±0.0006 eV. Most of the observed low lying torsion–vibrational structure in both S1 and D0 can be assigned using a one-dimensional torsional model plus low frequency vibrational modes whose identity is corroborated by the ab initio normal modes of D0. The intensities of certain weak, forbidden torsion–vibration combination bands in the S1–S0 spectrum are well predicted by a nuclear coordinate dependence of the electric dipole transition moment. The threefold methyl torsional barrier is V3=144.2±2.0 cm−1 in S1 and V3=456.5±2.0 cm−1 in D0. Ab initio calculations at the HF/6-31G* level find V3=481 cm−1 in S0 with the minimum energy conformation pseudo-trans, i.e., with one CH bond lying in the plane of the ring on the opposite side of the chlorine substituent. Spectral band intensities show that the minimum is pseudo-trans in S1 and D0 as well.
In both S1 and D0, excitation of either of the two lowest frequency out-of-plane bending modes, ν38 or ν37, leaves the methyl torsional potential essentially unchanged. In S0, S1, and D0, the barrier is substantially larger for ortho-chlorotoluene than for ortho-fluorotoluene, consistent with greater steric repulsion between the 3p chlorine lone pair and the CH bond pairs. The effects of π excitation and π ionization on the barrier are similar in ortho-chlorotoluene and ortho-fluorotoluene. Apparently both chlorine and fluorine are weak π donors that have similar effects on the crucial ring CC bond orders closest to methyl. Both the S1 and D0 spectra reveal several examples of torsion–vibrational coupling which perturbs torsional state energies and produces extra bands. Simple zeroth-order models of energy levels and coupling strengths fit experimental frequencies and band intensities well. Deperturbation yields coupling matrix elements between torsion and out-of-plane bending vibrations that fall in the narrow range 6–15 cm−1 in all cases. For three different molecules with widely varying methyl rotor barriers from 10 to 450 cm−1, the magnitude of such coupling matrix elements is similar, always in the range 3–15 cm−1. This provides guidance for theoretical models of intramolecular vibrational energy redistribution.
A Sponge-like Structure Involved in the Association and Transport of Maternal Products during Drosophila Oogenesis
Authors: Wilsch-Bräuninger Michaela , Schwarz Heinz , Nüsslein-Volhard Christiane 
Published: July 2002

Localization of maternally provided RNAs during oogenesis is required for formation of the antero–posterior axis of the Drosophila embryo. Here we describe a subcellular structure in nurse cells and oocytes which may function as an intracellular compartment for assembly and transport of maternal products involved in RNA localization. This structure, which we have termed “sponge body,” consists of ER-like cisternae, embedded in an amorphous electron-dense mass. It lacks a surrounding membrane and is frequently associated with mitochondria. The sponge bodies are not identical to the Golgi complexes. We suggest that the sponge bodies are homologous to the mitochondrial cloud in Xenopus oocytes, a granulo-fibrillar structure that contains RNAs involved in patterning of the embryo.
Exuperantia protein, the earliest factor known to be required for the localization of bicoid mRNA to the anterior pole of the Drosophila oocyte, is highly enriched in the sponge bodies but not an essential structural component of these. RNA staining indicates that sponge bodies contain RNA. However, neither the intensity of this staining nor the accumulation of Exuperantia in the sponge bodies is dependent on the amount of bicoid mRNA present in the ovaries. Sponge bodies surround nuage, a possible polar granule precursor. Microtubules and microfilaments are not present in sponge bodies, although transport of the sponge bodies through the cells is implied by their presence in cytoplasmic bridges. We propose that the sponge bodies are structures that, by assembly and transport of included molecules or associated structures, are involved in localization of mRNAs in Drosophila oocytes.
Chs7p, a New Protein Involved in the Control of Protein Export from the Endoplasmic Reticulum that Is Specifically Engaged in the Regulation of Chitin Synthesis in Saccharomyces cerevisiae
Authors: Trilla Jose A. , Durán Angel , Roncero Cesar 
Published: July 2002

The Saccharomyces cerevisiae CHS7 gene encodes an integral membrane protein located in the ER which is directly involved in chitin synthesis through the regulation of chitin synthase III (CSIII) activity. In the absence of CHS7 product, Chs3p, but not other secreted proteins, is retained in the ER, leading to a severe defect in CSIII activity and consequently, to a reduced rate of chitin synthesis. In addition, chs7 null mutants show the yeast phenotypes associated with a lack of chitin: reduced mating efficiency and lack of the chitosan ascospore layer, clear indications of Chs7p function throughout the S. cerevisiae biological cycle.
CHS3 overexpression does not lead to increased levels of CSIII because the Chs3p excess is retained in the ER. However, joint overexpression of CHS3 and CHS7 increases the export of Chs3p from the ER and this is accompanied by a concomitant increase in CSIII activity, indicating that the amount of Chs7p is a limiting factor for CSIII activity. Accordingly, CHS7 transcription is increased when elevated amounts of chitin synthesis are detected.
These results show that Chs7p forms part of a new mechanism specifically involved in Chs3p export from the ER and consequently, in the regulation of CSIII activity.
DOLOP—database of bacterial lipoproteins
Authors: Madan Babu M. , Sankaran K. 
Published: July 2002

Abstract
Summary: Bacterial lipoproteins and lipid modification are gaining importance owing to their essential nature, roles in pathogenesis and interesting commercial applications. We have created an exclusive knowledge base for bacterial lipoproteins by processing information from 510 entries to provide a list of 199 distinct lipoproteins with relevant links to molecular details. Features include functional classification, predictive algorithm for query sequences, primary sequence analysis and lists of predicted lipoproteins from 43 completed bacterial genomes along with interactive information exchange facility.
Availability: The website called Database Of bacterial LipOProteins (DOLOP) is available at http://www.mrc-lmb.cam.ac.uk/genomes/dolop along with additional information on the biosynthetic pathway, supplementary material and other related figures.
Contact: ksankaran@annauniv.edu; madanm@mrc-lmb.cam.ac.uk
* To whom correspondence should be addressed.
Safety and tolerability of quinupristin/dalfopristin: administration guidelines
Authors: Rubinstein E. , Prokocimer P. , Talbot G. H. 
Published: July 2002

Abstract
The safety and tolerability of quinupristin/dalfopristin were assessed in both comparative and non-comparative trials (2298 quinupristin/dalfopristin-treated patients). In comparative clinical trials, the most frequent systemic adverse events related to quinupristin/dalfopristin were nausea (4.6%), diarrhoea (2.7%), vomiting (2.7%) and skin rash (2.5%). The comparator group showed similar rates, except that nausea was significantly more common (7.2%; P = 0.01). In non-comparative trials, arthralgia and myalgia were reported most frequently but were reversible upon treatment discontinuation. The renal, inner ear, cardiovascular and central nervous systems were not implicated as significant target organs for toxicity. The most frequent local adverse events related to infusion of quinupristin/dalfopristin were inflammation, pain, oedema, infusion site reaction and thrombophlebitis. Results of laboratory tests while on therapy were comparable for quinupristin/dalfopristin and comparator groups, except that increases in conjugated bilirubin of &gt;5 × the upper limit of normal were reported in 5.5% of quinupristin/dalfopristin recipients; increases in total bilirubin of &gt;5 × the upper limit of normal occurred in 1.5%. Comparator recipients more frequently had increases in alanine aminotransferase and alkaline phosphatase. Quinupristin/dalfopristin inhibits the cytochrome P450 3A4-mediated metabolism of drugs including midazolam, nifedipine, terfenadine and cyclosporin. Therefore, plasma drug monitoring and/or dosage reduction of these agents is prudent. Concomitant administration of drugs that can prolong the electrocardiographic QTc interval should be avoided. Quinupristin/dalfopristin is visually and chemically compatible with commonly used drugs of various classes, but it is not compatible with sodium chloride solution and certain other drugs, including some antimicrobials. Therefore, when prescribing quinupristin/ dalfopristin, clinicians should be aware of the potential for peripheral venous intolerance, arthralgias and myalgias, increases in conjugated bilirubin, interactions with drugs metabolized by the cytochrome P450 3A4 isoenzyme and certain physico-chemical incompatibilities. However, multiple studies have shown that the safety and tolerability of quinupristin/dalfopristin are generally favourable, and that it provides clear benefits to ill patients with severe Gram-positive infections.
Binding of a fibrinogen mimetic stabilizes integrin αIIbβ3's open conformation
Authors: Hantgan Roy R. , Rocco Mattia , Nagaswami Chandrasekaran , Weisel John W. 
Published: July 2002

AbstractThe platelet integrin αIIbβ3 is representative of a class of heterodimeric receptors that upon activation bind extracellular macromolecular ligands and form signaling clusters. This study examined how occupancy of αIIbβ3's fibrinogen binding site affected the receptor's solution structure and stability. Eptifibatide, an integrin antagonist developed to treat cardiovascular disease, served as a high‐affinity, monovalent model ligand with fibrinogen‐like selectivity for αIIbβ3. Eptifibatide binding promptly and reversibly perturbed the conformation of the αIIbβ3 complex. Ligand‐specific decreases in its diffusion and sedimentation coefficient were observed at near‐stoichiometric eptifibatide concentrations, in contrast to the receptor‐perturbing effects of RGD ligands that we previously observed only at a 70‐fold molar excess. Eptifibatide promoted αIIbβ3 dimerization 10‐fold more effectively than less selective RGD ligands, as determined by sedimentation equilibrium. Eptifibatide‐bound integrin receptors displayed an ectodomain separation and enhanced assembly of dimers and larger oligomers linked through their stalk regions, as seen by transmission electron microscopy. Ligation with eptifibatide protected αIIbβ3 from SDS‐induced subunit dissociation, an effect on electrophoretic mobility not seen with RGD ligands. Despite its distinct cleft, the open conformer resisted guanidine unfolding as effectively as the ligand‐free integrin. Thus, we provide the first demonstration that binding a monovalent ligand to αIIbβ3's extracellular fibrinogen‐recognition site stabilizes the receptor's open conformation and enhances self‐association through its distant transmembrane and/or cytoplasmic domains. By showing how eptifibatide and RGD peptides, ligands with distinct binding sites, each affects αIIbβ3's conformation, our findings provide new mechanistic insights into ligand‐linked integrin activation, clustering and signaling.
Evaluating dosimetric accuracy of the 6 MV calibration on EBT3 film in the use of Ir‐192 high dose rate brachytherapy
Authors: Huang Lyu , Gaballa Hani , Chang Jenghwa 
Published: February 2022

AbstractPurposeTo evaluate the dosimetric accuracy of EBT3 film calibrated with a 6 MV beam for high dose rate brachytherapy and propose a novel method for direct film calibration with an Ir‐192 source.MethodsThe 6 MV calibration was performed in water on a linear accelerator (linac). The Ir‐192 calibration was accomplished by irradiating the film wrapped around a cylinder applicator with an Ir‐192 source. All films were scanned 1‐day post‐irradiation to acquire calibration curves for all three (red, blue, and green) channels. The Ir‐192 calibration films were also used for single‐dose comparison. Moreover, an independent test film under a H.A.M. applicator was irradiated and the 2D dose distribution was obtained separately for each calibration using the red channel data. Gamma analysis and point‐by‐point profile comparison were performed to evaluate the performance of both calibrations. The uncertainty budget for each calibration system was analyzed.ResultsThe red channel had the best performance for both calibration systems in the single‐dose comparison. We found a significant 4.89% difference from the reference for doses <250 cGy using the 6 MV calibration, while the difference was only 0.87% for doses >600 cGy. Gamma analysis of the 2D dose distribution showed the Ir‐192 calibration had a higher passing rate of 91.9% for the 1 mm/2% criterion, compared to 83.5% for the 6 MV calibration. Most failing points were in the low‐dose region (<200 cGy). The point‐by‐point profile comparison reported a discrepancy of 2%–3.6% between the Ir‐192 and 6 MV calibrations in this low‐dose region. The linac‐ and Ir‐192‐based dosimetry systems had an uncertainty of 4.1% (k = 2) and 5.66% (k = 2), respectively.ConclusionsDirect calibration of EBT3 films with an Ir‐192 source is feasible and reliable, while the dosimetric accuracy of 6 MV calibration depends on the dose range. The Ir‐192 calibration should be used when the measurement dose range is below 250 cGy.
Damage Trajectories in Systemic Sclerosis Using Group‐Based Trajectory Modeling
Authors: Barbacki Ariane , Baron Murray , Wang Mianbo , Zhang Yuqing , Stevens Wendy , Sahhar Joanne , Proudman Susanna , Nikpour Mandana , Man Ada ,   the Australian Scleroderma Interest Group and the Canadian Scleroderma Research Group
Published: February 2022

ObjectiveSystemic sclerosis (SSc) is an autoimmune disease characterized by progressive organ damage, which can be measured using the Scleroderma Clinical Trials Consortium Damage Index (SCTC‐DI). We aimed to identify whether distinct trajectories of damage accrual exist and to determine which variables are associated with different trajectory groups.MethodsIncident cases of SSc (<2 years) were identified in the Australian Scleroderma Interest Group and Canadian Scleroderma Research Group prospective registries. Group‐based trajectory modeling was used to identify SCTC‐DI trajectories over the cohort's first 5 annual visits. Baseline variables associated with trajectory membership in a univariate analysis were examined in multivariable models.ResultsA total of 410 patients were included. Three trajectory groups were identified: low (54.6%), medium (36.2%), and high (10.3%) damage. Patients with faster damage accrual had higher baseline SCTC‐DI scores. Older age (odds ratio [OR] 1.57 [95% confidence interval (95% CI) 1.18–2.10]), male sex (OR 2.55 [95% CI 1.10–5.88]), diffuse disease (OR 6.7 [95% CI 2.57–17.48]), tendon friction rubs (OR 5.4 [95% CI 1.86–15.66]), and elevated C‐reactive protein level (OR 1.98 [95% CI 1.49–2.63]) increased the odds of being in the high‐damage group versus the reference (low damage), whereas White ethnicity (OR 0.31 [95% CI 0.12–0.75]) and anticentromere antibodies (OR 0.24 [95% CI 0.07–0.77]) decreased the odds.ConclusionWe identified 3 trajectories of damage accrual in a combined incident SSc cohort. Several characteristics increased the odds of belonging to worse trajectories. These findings may be helpful in recognizing patients in whom early aggressive treatment is necessary.
Tribovoltaic Nanogenerators Based on MXene–Silicon Heterojunctions for Highly Stable Self‐Powered Speed, Displacement, Tension, Oscillation Angle, and Vibration Sensors
Authors: Luo Xiongxin , Liu Lindong , Wang Yi‐Chi , Li Jiayu , Berbille Andy , Zhu Laipan , Wang Zhong Lin 
Published: February 2022

AbstractTribovoltaic nanogenerators (TVNGs), an emerging high‐entropy energy harvesting technique, present great features such as low matching resistance, high current density, and continuous output performance. Here, an MXene layer and a semiconducting silicon wafer are assembled into a tribovoltaic nanogenerator (named MS‐TVNG). The output peak current of the MS‐TVNG reaches up to 22 µA for a P‐type (0.1–0.5 Ω cm) silicon wafer under a normal force of 4.56 N and a sliding speed of 2 m s−1. Owing to the unique metal characteristics of the MXene layer, the performance is superior to those previously reported TVNGs using traditional metals. The layered structure of MXene endows the real‐time MS‐TVNG with outstanding wear‐resistance and stable output properties. The performance of the MS‐TVNG can be tuned by the doping type and concentration of the silicon wafer, as well as by the pressure and the relative sliding speed between two friction surfaces. The MS‐TVNG has proven to be a solid foundation for high‐performance self‐powered speed sensors and has excellent potentials for applications in displacement, tension, oscillation angle, and vibration detection.
Bilayer Lubricant‐Infused Particulate Films as Slippery Protective Coatings with Durable Anticorrosion and Antifouling Performance
Authors: Chien Chih‐Hsuan , Chen Ting‐Lun , Wu Xiao‐Yan , Chen Yi‐Chen , Lee Pin‐Yan , Lin Lu‐Yin , Wang Wei‐Lung , Hsueh Han‐Yu 
Published: February 2022

AbstractIn this study, durable slippery colloidal coatings are created through the infiltration of particulate films with bilayer lubricant; the coatings exhibit remarkable surface‐protective performance, including anticorrosion, antifouling, self‐healing, anti‐icing, and self‐cleaning properties. Materials with low surface energy, namely polytetrafluoroethylene or polydimethylsiloxane, are used to form micelle dispersions, with particulate films then obtained through spray coating. In particular, the thermally driven viscous surfactants can serve as a bottom adhesive primer after thermal treatment, which significantly improve durability. After lubricant infusion as a top protective layer, bilayer lubricant‐infused slippery coatings are obtained without a complex hole‐making process being required. The anticorrosion and antifouling performance of colloid coatings infused with various functional lubricants—ionic liquid, silicone oil, and perfluoropolyether oils—is investigated. This study is the first to create bilayer lubricant‐infused colloid‐based surface systems (i.e., primer and protective lubricants) as protective coatings. The coatings can be employed in various applications, such as fuel transport, self‐cleaning windows, anticorrosion protection, nontoxic coatings for medical devices, and optical instruments.
In Situ Fabrication, Manipulation, and Mechanical Characterization of Free‐Standing Silica Thin Films Using Focused Ion Beam Scanning Electron Microscopy
Authors: Soleimani Mohammad , Maddala Sai P. , Wismans Martijn , Liao Wei‐Chih , van Breemen Lambèrt C. A. , van Benthem Rolf A. T. M. , Friedrich Heiner 
Published: February 2022

AbstractDetermination of mechanical properties of (silica) thin films is important for the development of new applications. However, a versatile approach for small‐scale sample fabrication and in situ mechanical testing of these materials is currently lacking which can overcome the existing difficulties in conventional testing approaches. Here, it is shown that by combining focused ion beam scanning electron microscopy (FIB‐SEM) with micromanipulators free‐standing silica beams of the desired dimensions can be fabricated. Using in situ bending tests on such beams inside the SEM and finite element method simulations, the Young's modulus of thin‐film silica and the effects of gallium ion beam radiation on Young's modulus are determined. Furthermore, the effects of controlled relative humidity on the mechanical behavior of silica beams are investigated. The demonstrated FIB‐SEM approach can be extended to other materials and preparation conditions to measure, model, and optimize mechanical properties of thin films for a wide range of (coating) applications.
Ultrasensitive Detection of Heavy Metal Ions with Scalable Singular Phase Thin Film Optical Coatings
Authors: Rao Anirudha R. , Sreekanth Kandammathe Valiyaveedu , Sreejith Sivaramapanicker , Jose Vishal , Pethe Shreyas , Singh Ranjan 
Published: February 2022

AbstractIdentification of spectroscopically silent heavy‐metal ions in environmental and bio‐analytical samples has gained immense importance. Lowering the limit of detection of these ions at low concentrations is crucial for biomedicine and food safety applications. Optical chemical sensors have shown great potential in improving the sensing solutions for heavy‐metal ions because of their fast and label‐free detection capabilities. However, achieving high sensitivity without compromising on scalability and simplicity is challenging. Here, we experimentally demonstrate the detection of heavy metal ions at ultralow concentrations using lithography‐free scalable thin film optical coatings that show singular behavior of phase of light at the point‐of‐darkness. Since the phase‐sensitive optical techniques have shown superior sensitivity over traditional sensing techniques based on spectroscopy, we use this extreme phase change to detect zinc ions concentration down to femtomolar. In particular, it allows us to monitor very small changes in refractive index due to the real‐time binding of zinc ions on a poly (lactic‐co‐glycolic acid) functionalized sensor surface. This cost‐effective extreme sensitivity sensing platform can be used for the label‐free detection of various heavy metal ions by properly functionalizing the sensor surface.
Stimuli‐Responsive Antibacterial Materials: Molecular Structures, Design Principles, and Biomedical Applications
Authors: Wang Xianghong , Shan Mengyao , Zhang Shike , Chen Xin , Liu Wentao , Chen Jinzhou , Liu Xuying 
Published: February 2022

AbstractInfections are regarded as the most severe complication associated with human health, which are urgent to be solved. Stimuli‐responsive materials are appealing therapeutic platforms for antibacterial treatments, which provide great potential for accurate theranostics. In this review, the advantages, the response mechanisms, and the key design principles of stimuli‐responsive antibacterial materials are highlighted. The biomedical applications, the current challenges, and future directions of stimuli‐responsive antibacterial materials are also discussed. First, the categories of stimuli‐responsive antibacterial materials are comprehensively itemized based on different sources of stimuli, including external physical environmental stimuli (e.g., temperature, light, electricity, salt, etc.) and bacterial metabolites stimuli (e.g., acid, enzyme, redox, etc.). Second, structural characteristics, design principles, and biomedical applications of the responsive materials are discussed, and the underlying interrelationships are revealed. The molecular structures and design principles are closely related to the sources of stimuli. Finally, the challenging issues of stimuli‐responsive materials are proposed. This review will provide scientific guidance to promote the clinical applications of stimuli‐responsive antibacterial materials.