bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous curvature and thermodynamic stability of mixed amphiphilic layers
Authors: May Sylvio , Ben-Shaul Avinoam 
Published: July 2002

The elastic behavior of mixed bilayers composed of two amphiphilic components with different chain length (and identical head groups) is studied using two molecular level models. In both, the bilayer free energy is expressed as a sum of chain, head group and interfacial contributions as well as a mixing entropy term. The head group and interfacial terms are modeled using simple phenomenological but general expressions. The models differ in their treatment of the chain conformational free energy. In one it is calculated using a detailed mean-field molecular theory. The other is based on a simple ‘‘compression’’ model. Both models lead to similar conclusions. Expressing the bilayer free energy as a sum of its two monolayer contributions, a thermodynamic stability analysis is performed to examine the possibility of spontaneous vesicle formation. To this end, we expand the bilayer free energy as a power series (up to second order) in terms of the monolayer curvatures, their amphiphilic compositions and the average cross sectional areas per molecule; all variables are coupled, with the molecular composition and areas treated as degrees of freedom which are allowed to relax during bending. Using reasonable molecular interaction parameters we find that a second order transition from a planar to a curved (vesicle) geometry in a randomly mixed bilayer is unlikely. Most of our analysis is devoted to calculating the spontaneous curvature and the bending rigidity of the bilayer as a function of its amphiphile chain composition.
We find that adding short chain amphiphiles to a layer of long chain molecules reduces considerably its bending rigidity, as already known from calculations involving only the chain contributions. However, we find that inclusion of head group and interfacial interactions moderates the effect of the added short chains. We also find that the bending rigidity of pure monolayers is approximately linear in chain length, as compared to the nearly cubic dependence implied by the chain free energy alone (at constant head group area). Our main result involves the calculation of the spontaneous curvature as a function of composition. We find, for different chain mixtures, that upon adding short chains to long chain monolayers, the spontaneous curvature first increases nearly linearly with composition and then (beyond mole fraction of about 0.5) begins to saturate towards the spontaneous curvature of a pure short chain layer. Qualitative arguments are provided to explain this behavior.
The acute influence of tobacco smoking on adhesion molecule expression on monocytes and neutrophils and on circulating adhesion molecule levels in vivo
Authors: Scott D. A. , Todd D. H. , Coward P. Y. , Wilson R. F. , Odell E. W. , Poston R. N. , Matthews J. P. , Palmer R. M. 
Published: July 2002

AbstractSoluble adhesion molecules have been reported as risk markers of a wide range of human diseases and specific adhesion molecules may play a direct role in pathological processes. Serum soluble intercellular adhesion molecule‐1 (sICAM‐1) is known to be significantly elevated in smokers compared to non‐smokers. We examined the acute effects of smoking a standard 2R1 research cigarette on the serum concentration of sICAM‐1 and other circulating adhesion molecules (sP‐selectin, sE‐selectin, sL‐selectin, sVCAM‐1 and sPECAM‐1) in heavy smokers (serum cotinine ≥ 100 ng/ml), light smokers (serum cotinine ≤ 60 ng/ml) and non‐smokers (serum cotinine ≤ 10 ng/ml) by ELISA. Adhesion molecule expression on the cell surface of monocytes and neutrophils in peripheral blood was examined by flow cytometry. The sICAM‐1 concentration directly correlated to serum cotinine concentration (p= 0.047) and nicotine load (p= 0.033) in smokers and was significantly elevated compared to non‐smokers (p= 0.037). Other than a decrease in the concentration of sP‐selectin over 1 hour regardless of smoking, no significant temporal alterations of any adhesion molecule were observed following the smoking experience or in the non‐smoking control group. No significant difference in surface expression of ICAM‐1, CD18, PECAM‐1 or L‐selectin on peripheral monocytes or neutrophils was observed over a 1‐hour period following smoking. These data suggest that the elevated concentration of sICAM‐1 in smokers is not due to an immediate effect of smoking.
Differential Association of Syntrophin Pairs with the Dystrophin Complex
Authors: Peters Matthew F. , Adams Marvin E. , Froehner Stanley C. 
Published: July 2002

The syntrophins are a multigene family of intracellular dystrophin-associated proteins comprising three isoforms, α1, β1, and β2. Based on their domain organization and association with neuronal nitric oxide synthase, syntrophins are thought to function as modular adapters that recruit signaling proteins to the membrane via association with the dystrophin complex. Using sequences derived from a new mouse β1-syntrophin cDNA, and previously isolated cDNAs for α1- and β2-syntrophins, we prepared isoform-specific antibodies to study the expression, skeletal muscle localization, and dystrophin family association of all three syntrophins. Most tissues express multiple syntrophin isoforms. In mouse gastrocnemius skeletal muscle, α1- and β1-syntrophin are concentrated at the neuromuscular junction but are also present on the extrasynaptic sarcolemma. β1-syntrophin is restricted to fast-twitch muscle fibers, the first fibers to degenerate in Duchenne muscular dystrophy. β2-syntrophin is largely restricted to the neuromuscular junction.
The sarcolemmal distribution of α1- and β1-syntrophins suggests association with dystrophin and dystrobrevin, whereas all three syntrophins could potentially associate with utrophin at the neuromuscular junction. Utrophin complexes immunoisolated from skeletal muscle are highly enriched in β1- and β2-syntrophins, while dystrophin complexes contain mostly α1- and β1-syntrophins. Dystrobrevin complexes contain dystrophin and α1- and β1-syntrophins. From these results, we propose a model in which a dystrophin–dystrobrevin complex is associated with two syntrophins. Since individual syntrophins do not have intrinsic binding specificity for dystrophin, dystrobrevin, or utrophin, the observed preferential pairing of syntrophins must depend on extrinsic regulatory mechanisms.
Endothelial Cell Laminin Isoforms, Laminins 8 and 10, Play Decisive Roles in T Cell Recruitment across the Blood–Brain Barrier in Experimental Autoimmune Encephalomyelitis
Authors: Sixt Michael , Engelhardt Britta , Pausch Friederike , Hallmann Rupert , Wendler Olaf , Sorokin Lydia M. 
Published: July 2002

An active involvement of blood–brain barrier endothelial cell basement membranes in development of inflammatory lesions in the central nervous system (CNS) has not been considered to date. Here we investigated the molecular composition and possible function of the extracellular matrix encountered by extravasating T lymphocytes during experimental autoimmune encephalomyelitis (EAE).
Endothelial basement membranes contained laminin 8 (α4β1γ1) and/or 10 (α5β1γ1) and their expression was influenced by proinflammatory cytokines or angiostatic agents. T cells emigrating into the CNS during EAE encountered two biochemically distinct basement membranes, the endothelial (containing laminins 8 and 10) and the parenchymal (containing laminins 1 and 2) basement membranes. However, inflammatory cuffs occurred exclusively around endothelial basement membranes containing laminin 8, whereas in the presence of laminin 10 no infiltration was detectable. In vitro assays using encephalitogenic T cell lines revealed adhesion to laminins 8 and 10, whereas binding to laminins 1 and 2 could not be induced. Downregulation of integrin α6 on cerebral endothelium at sites of T cell infiltration, plus a high turnover of laminin 8 at these sites, suggested two possible roles for laminin 8 in the endothelial basement membrane: one at the level of the endothelial cells resulting in reduced adhesion and, thereby, increased penetrability of the monolayer; and secondly at the level of the T cells providing direct signals to the transmigrating cells.
Comparing function and structure between entire proteomes
Authors: Liu Jinfeng , Rost Burkhard 
Published: July 2002

AbstractMore than 30 organisms have been sequenced entirely. Here, we applied a variety of simple bioinformatics tools to analyze 29 proteomes for representatives from all three kingdoms: eukaryotes, prokaryotes, and archaebacteria. We confirmed that eukaryotes have relatively more long proteins than prokaryotes and archaes, and that the overall amino acid composition is similar among the three. We predicted that ∼15%–30% of all proteins contained transmembrane helices. We could not find a correlation between the content of membrane proteins and the complexity of the organism. In particular, we did not find significantly higher percentages of helical membrane proteins in eukaryotes than in prokaryotes or archae. However, we found more proteins with seven transmembrane helices in eukaryotes and more with six and 12 transmembrane helices in prokaryotes. We found twice as many coiled‐coil proteins in eukaryotes (10%) as in prokaryotes and archaes (4%–5%), and we predicted ∼15%–25% of all proteins to be secreted by most eukaryotes and prokaryotes. Every tenth protein had no known homolog in current databases, and 30%–40% of the proteins fell into structural families with >100 members. A classification by cellular function verified that eukaryotes have a higher proportion of proteins for communication with the environment. Finally, we found at least one homolog of experimentally known structure for ∼20%–45% of all proteins; the regions with structural homology covered 20%–30% of all residues. These numbers may or may not suggest that there are 1200–2600 folds in the universe of protein structures. All predictions are available at http://cubic.bioc.columbia.edu/genomes.
Efficient In Vitro Full‐Sense‐Codons Protein Synthesis
Authors: Wu Yang , Tang Mengtong , Wang Zhaoguan , Yang Youhui , Li Zhong , Liang Shurui , Yin Peng , Qi Hao 
Published: June 2022

AbstractTermination of translation is essential but hinders applications of genetic code engineering, e.g., unnatural amino acids incorporation and codon randomization mediated saturation mutagenesis. Here, for the first time, it is demonstrated that E. coli Pth and ArfB together play an efficient translation termination without codon preference in the absence of class‐I release factors. By degradation of the targeted protein, both essential and alternative termination types of machinery are completely removed to disable codon‐dependent termination in cell extract. Moreover, a total of 153 engineered tRNAs are screened for efficient all stop‐codons decoding to construct a codon‐dependent termination defect in vitro protein synthesis with all 64 sense‐codons, iPSSC. Finally, this full sense genetic code achieves significant improvement in the incorporation of distinct unnatural amino acids at up to 12 positions and synthesis of protein encoding consecutive NNN codons. By decoding all information in nucleotides to amino acids, iPSSC may hold great potential in building artificial protein synthesis beyond the cell.
TNIK Inhibition Has Dual Synergistic Effects on Tumor and Associated Immune Cells
Authors: Kim Jaehee , Oh Juhyun , Peterson Hannah M. , Carlson Jonathan C.T. , Pittet Mikael J. , Weissleder Ralph 
Published: June 2022

AbstractTreatment with checkpoint inhibitors can be extraordinarily effective in a fraction of patients, particularly those whose tumors are pre‐infiltrated by T cells. In others, efficacy is considerably lower, which has led to interest in developing strategies for sensitization to immunotherapy. Using various colorectal cancer mouse models, it is shown that the use of Traf2 and Nck‐interacting protein kinase inhibitors (TNIKi) unexpectedly increases tumor infiltration by PD‐1+ CD8+ T cells, thus contributing to tumor control. This appears to happen by two independent mechanisms, by inducing immunogenic cell death and separately by directly activating CD8. The use of TNIKi achieves complete tumor control in 50% of mice when combined with checkpoint inhibitor targeting PD‐1. These findings reveal immunogenic properties of TNIKi and indicate that the proportion of colorectal cancers responding to checkpoint therapy can be increased by combining it with immunogenic kinase inhibitors.
Exploring Interfaces Through Synchrotron Radiation Characterization Techniques: A Graphene Case
Authors: Ding Yiran , Shi Haiwen , Zeng Mengqi , Fu Lei 
Published: June 2022

AbstractRecently, many breakthroughs have been made in graphene research, allowing scientists to explore and understand the material world from a two‐dimensional (2D) perspective. The interface issue of graphene is the most important, because all of its atoms are exposed to the interface for this atomically thin material. The 2D nature necessitates a sensitive and non‐destructive interface probe to detect the structure and properties. Synchrotron radiation (SR) characterization techniques, with the ultra‐high resolution and extremely wide energy range, have been utilized with increasing frequency to explore the challenging interface sciences. In this review, these interface characterization techniques based on SR and how they monitor the structure evolution of graphene in different interfaces such as graphene–substrate and graphene–graphene interface are first introduced. Graphene's layer number, interlayer spacing, and stacking order are governed by these interfaces, determining the final properties. Then, the property detection and modulation in different interfaces of graphene are also discussed. Finally, the current challenges and outlook on the future development for SR techniques to characterize graphene interface are presented.
Approach to Determine the Density‐of‐States Effective Mass with Carrier Concentration‐Dependent Seebeck Coefficient
Authors: Lee Kyu Hyoung , Kim Sang‐il , Lim Jong‐Chan , Cho Jung Young , Yang Heesun , Kim Hyun‐Sik 
Published: June 2022

AbstractBand engineering is an effective strategy to improve the electronic transport properties of semiconductors. In thermoelectric materials research, density‐of‐states effective mass is an undoubted key factor in verifying the band engineering effect and establishing a strategy for enhancing thermoelectric performance. However, estimation of the effective mass is demanding or inaccurate depending on the methods taken. A simple equation is proposed, valid for all degeneracy: Log10 (md*T/300) = (2/3) Log10 (n) − (2/3) [20.3 − (0.00508 × |S|) + (1.58 × 0.967|S|)] that utilizes experimentally determined Seebeck coefficient (S) and carrier concentration (n) to determine the effective mass (md*) at a temperature (T). This straightforward equation, which gives an accurate analysis of the band modulation in terms of md*, is indispensable in designing thermoelectric materials of maximized performance.
Super Stretchable, Self‐Healing, Adhesive Ionic Conductive Hydrogels Based on Tailor‐Made Ionic Liquid for High‐Performance Strain Sensors
Authors: Yao Xue , Zhang Sufeng , Qian Liwei , Wei Ning , Nica Valentin , Coseri Sergiu , Han Fei 
Published: June 2022

AbstractIonic conductive hydrogels (ICHs) integrate the conductive performance and soft nature of tissue‐like materials to imitate the features of human skin with mechanical and sensory traits; thus, they are considered promising substitutes for conventional rigid metallic conductors when fabricating human‐motion sensors. However, the simultaneous incorporation of excellent stretchability, toughness, ionic conductivity, self‐healing, and adhesion via a simple method remains a grand challenge. Herein, a novel ICH platform is proposed by designing a phenylboronic acid‐ionic liquid (PBA‐IL) with multiple roles that simultaneously realize the highly mechanical, electrical, and versatile properties. This elaborately designed semi‐interpenetrating network ICH is fabricated via a facile one‐step approach by introducing cellulose nanofibrils (CNFs) into the PBA‐IL/acrylamide cross‐linked network. Ingeniously, the dynamic boronic ester bonds and physical interactions (hydrogen bonds and electrostatic interactions) of the cross‐linked network endow these hydrogels with remarkable stretchability (1810 ± 38%), toughness (2.65 ± 0.03 MJ m−3), self‐healing property (92 ± 2% efficiency), adhesiveness, and transparency. Moreover, the construction of this material shows that CNFs can synergistically enhance mechanical performance and conductivity. The wide working strain range (≈1000%) and high sensitivity (GF = 8.36) make this ICH a promising candidate for constructing the next generation of gel‐based strain sensor platforms.
Non‐PCR Ultrasensitive Detection of Viral RNA by a Nanoprobe‐Coupling Strategy: SARS‐CoV‐2 as an Example
Authors: Yu Zhiguo , Fang Wenming , Yang Yannan , Yao Heliang , Hu Ping , Shi Jianlin 
Published: June 2022

AbstractDeveloping efficient and highly sensitive diagnostic techniques for early detections of pathogenic viruses such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) is vitally important for preventing its widespread. However, the conventional polymerase chain reaction (PCR)‐based detection features high complexity, excessive time‐consumption, and labor‐intensiveness, while viral protein‐based detections suffer from moderate sensitivity and specificity. Here, a non‐PCR but ultrasensitive viral RNA detection strategy is reported based on a facile nanoprobe‐coupling strategy without enzymatic amplification, wherein PCR‐induced bias and other shortcomings are successfully circumvented. This approach endows the viral RNA detection with ultra‐low background to maximum signal ratio in the linear signal amplification by using Au nanoparticles as reporters. The present strategy exhibits 100% specificity toward SARS‐CoV‐2 N gene, and ultrasensitive detection of as low as 52 cp mL−1 of SARS‐CoV‐2 N gene without pre‐PCR amplification. This approach presents a novel ultrasensitive tool for viral RNA detections for fighting against COVID‐19 and other types of pathogenic virus‐caused diseases.
Magnetic Alignment for Plasmonic Control of Gold Nanorods Coated with Iron Oxide Nanoparticles
Authors: Rizvi Mehedi H. , Wang Ruosong , Schubert Jonas , Crumpler William D. , Rossner Christian , Oldenburg Amy L. , Fery Andreas , Tracy Joseph B. 
Published: June 2022

AbstractPlasmonic nanoparticles that can be manipulated with magnetic fields are of interest for advanced optical applications, diagnostics, imaging, and therapy. Alignment of gold nanorods yields strong polarization‐dependent extinction, and use of magnetic fields is appealing because they act through space and can be quickly switched. In this work, cationic polyethyleneimine‐functionalized superparamagnetic Fe3O4 nanoparticles (NPs) are deposited on the surface of anionic gold nanorods coated with bovine serum albumin. The magnetic gold nanorods (MagGNRs) obtained through mixing maintain the distinct optical properties of plasmonic gold nanorods that are minimally perturbed by the magnetic overcoating. Magnetic alignment of the MagGNRs arising from magnetic dipolar interactions on the anisotropic gold nanorod core is comprehensively characterized, including structural characterization and enhancement (suppression) of the longitudinal surface plasmon resonance and suppression (enhancement) of the transverse surface plasmon resonance for light polarized parallel (orthogonal) to the magnetic field. The MagGNRs can also be driven in rotating magnetic fields to rotate at frequencies of at least 17 Hz. For suitably large gold nanorods (148 nm long) and Fe3O4 NPs (13.4 nm diameter), significant alignment is possible even in modest (<500 Oe) magnetic fields. An analytical model provides a unified understanding of the magnetic alignment of MagGNRs.
Förster Resonance Energy Transfer in Luminescent Solar Concentrators
Authors: Zhang Bolong , Lyu Guanpeng , Kelly Elaine A. , Evans Rachel C. 
Published: June 2022

AbstractLuminescent solar concentrators (LSCs) are an emerging technology to collect and channel light from a large absorption area into a smaller one. They are a complementary technology for traditional solar photovoltaics (PV), particularly suitable for application in urban or indoor environments where their custom colors and form factors, and performance under diffuse light conditions may be advantageous. Förster resonance energy transfer (FRET) has emerged as a valuable approach to overcome some of the intrinsic limitations of conventional single lumophore LSCs, such as reabsorption or reduced quantum efficiency. This review outlines the potential of FRET to boost LSC performance, using highlights from the literature to illustrate the key criteria that must be considered when designing an FRET‐LSC, including both the photophysical requirements of the FRET lumophores and their interaction with the host material. Based on these criteria, a list of design guidelines intended to aid researchers when they approach the design of a new FRET‐LSC system is presented. By highlighting the unanswered questions in this field, the authors aim to demonstrate the potential of FRET‐LSCs for both conventional solar‐harvesting and emerging LSC‐inspired technologies and hope to encourage participation from a diverse researcher base to address this exciting challenge.
Laminated Monolithic Perovskite/Silicon Tandem Photovoltaics
Authors: Roger Julie , Schorn Luisa K. , Heydarian Minasadat , Farag Ahmed , Feeney Thomas , Baumann Daniel , Hu Hang , Laufer Felix , Duan Weiyuan , Ding Kaining , Lambertz Andreas , Fassl Paul , Worgull Matthias , Paetzold Ulrich W. 
Published: June 2022

AbstractPerovskite/silicon tandem photovoltaics have attracted enormous attention in science and technology over recent years. In order to improve the performance and stability of the technology, new materials and processes need to be investigated. However, the established sequential layer deposition methods severely limit the choice of materials and accessible device architectures. In response, a novel lamination process that increases the degree of freedom in processing the top perovskite solar cell (PSC) is proposed. The very first prototypes of laminated monolithic perovskite/silicon tandem solar cells with stable power output efficiencies of up to 20.0% are presented. Moreover, laminated single‐junction PSCs are on par with standard sequential layer deposition processed devices in the same architecture. The numerous advantages of the lamination process are highlighted, in particular the opportunities to engineer the perovskite morphology, which leads to a reduction of non‐radiative recombination losses and and an enhancement in open‐circuit voltage (Voc). Laminated PSCs exhibit improved stability by retaining their initial efficiency after 1‐year aging and show good thermal stability under prolonged illumination at 80 °C. This lamination approach enables the research of new architectures for perovskite‐based photovoltaics and paves a new route for processing monolithic tandem solar cells even with a scalable lamination process.
A unique cardiovascular presentation of Marfan syndrome
Authors: Otero Luna Andrea , Park Kaylee B. , Schauer Jenna , Castera Mark , Quintana Grijalba Carolina , Chikkabyrappa Sathish Mallenahalli , Tjoeng Yuen Lie , Romberg Erin K. , Olson Aaron , Glass Ian A. , Young Luciana 
Published: June 2022

AbstractWe report a neonate with severe Marfan syndrome (MS), prenatally identified to have persistent atrial tachycardia, biventricular dysfunction, and an unusual structure within the atria. Detailed postnatal echocardiographic evaluation and cross‐sectional imaging confirmed congenital pseudoaneurysm of the mitral‐aortic intervalvular fibrosa. Emergent testing by next‐generation sequencing identified a FBN1 pathological variant, key to establishing goals of care. To our knowledge, this is the first reported case of a congenital pseudoaneurysm of the mitral‐aortic intervalvular fibrosa in MS.