bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of staphylococcal σ-haemolysin on the secretory activity of the pancreatic β-cell
Authors: Morgan Noel G. , Fitzhugh Alexandra J. , Montague William 
Published: February 2005

The secretion of insulin from isolated rat islets of Langerhans was found to be stimulated by the surface-active staphylococcal exotoxin, σ-haemolysin. The response was dependent on the concentration of σ-haemolysin, was rapid in onset, and could be maintained for at least an hour in the presence of the agent. The rate of secretion rapidly declined on removal of σ-haemolysin and the islets remained responsive to glucose follow!ng toxin treatment.
Further characterization of the interaction of this agent with the σ-cell plasma membrane may provide valuable information concerning the role played by this membrane in the regulation of insulin secretion.
The pharmacodynamic action of the cyclic AMP phosphodiesterase inhibitor rolipram on prolactin producing rat pituitary adenoma (GH4C1) cells
Authors: Gordeladze Jan O. 
Published: February 2005

Rolipram (4-(3-cyclopentyloxy-4-methoxyphenyl)-2-pyrrolidone) represents a new class of specific low Km cAMP phosphodiesterase (PDE) inhibitors. This compound enhances basal, hormone- and forskolin-elicited cAMP accumulation in prolactin (PRL) producing rat pituitary adenoma (GH4C1) cells in culture (ED50=5·10−8 M). This effect is due to a selective inhibition of the low Km cAMP PDE (type III), since neither basal nor hormone-stimulated adenylate cyclase (AC) nor the Ca2+/calmodulin-dependent PDE were affected by rolipram. The drug enhanced vasoactive intestinal polypeptide (VIP)-stimulated PRL-secretion, while thyroliberin (TRH)- and 12-0-tetradecanoyl phorbol-13-acetate (TPA)-elicited PRL egress were slightly reduced indicating a cAMP-mediated reduction of protein kinase C (PK-C) mediated PRL release. Interestingly, inhibition of PRL secretion by somatostatin (SRIH) was completely suppressed suggesting cAMP-mediated inactivation of some GTP-binding protein(s) of the αi family (Gαi2 or Gk). Rolipram did not affect phosphoinositide metabolism (i.e. IP3 accumulation), neither acutely nor after long term administration. Rolipram, like the cAMP PDE inhibitor Ro 20–1724, did not influence AC and PDE I, but dose-dependently inhibited PDE III activity.Long term incubation of GH4C1 cells with rolipram in the presence of noradrenaline (NA) exerted a marginal decrease of β-receptor number, AC activation and cAMP accumulation, while Ro 20–1724 brought about a marked down-regulation and desensitization of the AC complex.In summary, rolipram selectively interacts with PDE III in rat pituitary adenoma cells in culture and does not result in β-adrenoceptor AC downregulation. These features are not shared by the other drugs tested.
Effects of membrane lipid and fluidity modifications on HIV-1 infectibility of primate lymphocytesin vitro
Authors: Zimmer J. Pascal , Lehr Hans A. , Hübner Christoph , Lindner Stephan G. , Ramsperger Ralf , Claussen Matthias , Kohlschütter Alfried , Schmitz Herbert 
Published: February 2005

Although most non-human primates, except the chimpanzee and the gibbon in vivo are not infectible by HIV-1, lymphocytes of several of these species can be infected by HIV-1 in vitro.In order to investigate whether the in vitro infectibility of primate lymphocytes might be attributed to plasma membrane adaptation processes or to serum factors, we compared HIV-1 infectibility of cultivated peripheral blood lymphocytes of macaques and of baboons on day one and on day ten of cultivation. These data were correlated to plasma membrane lipid composition and membrane fluidity.We found a correlation between increased HIV-1 in vitro infectibility and changes in plasma membrane lipid composition resulting in decreased membrane fluidity of cultured primate lymphocytes.
Restriction fragment analysis of the HLA Class II region: Application to tissue transplantation
Authors: Bushell Andrew , Wood Kathryn J. 
Published: February 2005

Southern blotting and hybridization with locus specific probes is a reliable method for the determination of HLA Class II specificities and in conjunction with several other techniques is providing valuable information on the nature of Class II polymorphisms in man. In terms of the identification of Class II specificities in transplantation however, the advanced nature of DR serology means that DRβ restriction fragment analysis is probably limited only to those situations where serological methods have been unsuccessful.Whether DQ and DP incompatibilities can evoke rejection responses in vivo remains to be fully ascertained although our preliminary data suggest that DQ mismatches probably have little effect upon graft outcome. Restriction fragment analysis is particularly attractive in that in enables reliable retrospective studies to be performed in conjunction with prolonged clinical follow up, and the technique will clearly continue to contribute significantly to our understanding of the importance of these molecules in transplantation.
Evidence for the regulation of the activity of protein kinase C through changes in membrane properties
Authors: Epand Richard M. , Epand Raquel F. , Leon Bryan T.-C. , Menger Fredric M. , Kuo J. F. 
Published: February 2005

We measured the effects of two branched-chain analogs of distearoyl-phosphatidylcholine, containing either a methyl or an n-butyl group at the 8 position, on the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine. The former compound raised the bilayer to hexagonal phase transition temperature while the latter compound lowered it. The opposite effects of these amphiphiles on protein kinase C activity (inhibition and activation, respectively) correlated with their effects on lipid polymorphism. Because of the similarity of the structures of these two compounds, it seems likely that their opposite effects on the activity of protein kinase C is a result of their alteration of the lipid environment of the membrane rather than to binding to a specific site on the protein.
We also compared the effects of hexachlorophene on lipid polymorphism and protein kinase C activity at high and at low calcium concentrations. We also found that the effect of hexachlorophene forming a complex with Ca2+ is to increase both the hexagonal phase forming propensity of the membrane as well as to increase the activity of protein kinase C, again demonstrating the correlation between lipid phase propensity and effects on protein kinase C activity.
Carboxyterminal telopeptide of type I collagen, ICTP, as a marker of matrix degradation in neonatal mouse calvarial bones, in vitro
Authors: Ljunggren Östen , Ljunghall Sverker 
Published: February 2005

Bone resorption, in vitro, is often measured as the release of prelabelled45Ca from neonatal mouse calvarial bones, or from fetal rat long bones. In this report we describe a technique to measure the breakdown of bone-matrix, in vitro. We also describe a new way to dissect neonatal mouse calvarial bones, in order to obtain large amounts of bone samples.
Twelve bone fragments were dissected out from each mouse calvaria and were thereafter cultured in CMRL 1066 culture medium in serum-free conditions in 0.5 cm2 multiwell culture dishes. Matrix degradation after treatment with parathyroid hormone was assessed by measuring the amount of carboxyterminal telopeptide of type I collagen (ICTP) by RIA. The data on matrix degradation was compared to the release of prelabelled45Ca from neonatal mouse calvarial bones. We found that the dose-responses for parathyroid hormone-induced release of prelabelled45Ca and ICTP were identical.
In conclusion: RIA-analysis of the ICTP-release is an easy and accurate method to measure degradation of bone-matrix, in vitro. Furthermore, the new dissection technique, described in this report, makes it easy to obtain large amounts of bone samples and thus to perform extensive experiments, e.g. dose-responses for agents that enhance bone resorption.
Effects of parathyroid hormone on cyclic AMP-formation and cytoplasmic free Ca2+ in the osteosarcoma cell line UMR 106-01
Authors: Ljunggren Östen , Johansson Hans , Lerner Ulf H. , Lindh Erik , Ljunghall Sverker 
Published: February 2005

The effects of parathyroid hormone (PTH) on cytoplasmic free CA2+ (Cai2+) and cAMP-formation were investigated in the rat osteosarcoma cell line UMR 106-01.In fura-2 loaded adherent single cells bPTH 1–34 (10 nM−1μM) induced a rapid transient increase in Cai2+ in 11% of the studied cells. In fura-2 tracings from UMR 106-01 cells in suspension, bPTH 1–34 (0.1 μM) induced a transient increase in Cai2+ in 20% of the experiments. The transient increase in Cai2+ seen in suspensions of cells was not abolished by addition of EGTA (2.5 mM) prior to challenge with PTH, suggesting that the increase in Cai2+ was derived from intracellular stores.A marked rapid increase in cAMP-formation was observed in all experiments with cells in suspension, also in the experiments where PTH did not affect Cai2+.These data show that PTH causes a release of Ca2+ from intracellular stores in a small percentage of osteosarcoma UMR 106-01 cells, and that PTH is capable of inducing an increase in cAMP-formation without affecting Cai2+ in osteoblasts.
On the involvement of cyclic AMP and extracellular Ca2+ in the regulation of hormone release from rat pituitary tumour (GH3) cells in culture
Authors: Sletholt Kjersti , Haug Egil , Gautvik Kaare M. 
Published: February 2005

Thyroliberin (TRH), dibutyryl cyclic AMP (db-cAMP), and 3-isobutyl-l-methylxanthine (MIX) had a stimulatory effect on prolactin (PRL) and growth hormone (GH) release from GH 3 cells. Half-maximal and maximal effects were observed for TRH at 2.5 nM and 10 nM; for db-cAMP at 0.6 mM and 5 mM, respectively. MIX (0.1 mM-1 mM) induced a dose-dependent accumulation of cellular cyclic AMP, while the hormone release was already maximally stimulated at 0.1 mM MIX. The maximal effects on hormone release of TRH and db-cAMP, but not of TRH and MIX, were additive.
The Ca2+ channel blockers Co2+ (5 mM) and verapamil (100 μM) and the Ca2+ chelator EGTA (4 mM) abolished the stimulatory effect of TRH (1 μM) on hormone release. Co2+ and verapamil, but not EGTA, inhibited the stimulatory effect of db-cAMP (5 mM) on hormone release. The inhibitory effects of Co2+ and verapamil on GH release were counteracted by the combination of TRH and db-cAMP. For PRL release Co2+, but not verapamil, was able to inhibit the combined action of TRH and db-cAMP. Co2+, verapamil, and EGTA eliminated the stimulatory effect of MIX (1 mM) on PRL release while only Co2+ and EGTA affected the GH release. Hormone release in the presence of MIX plus verapamil or EGTA, but not Co2+, was increased by TRH.
The calmodulin antagonist trifluoperazine (TFP) at 30 μM inhibited basal hormone release and hormone release stimulated by TRH (1 μM), db-cAMP (5 mM), and MIX (1 mM). The Ca2+ ionophore A23187 (5 μM) had a stimulatory effect on basal hormone release which was abolished by 30 μM TFP.
Increasing frequency of Gram‐positive bacteria in spontaneous bacterial peritonitis
Authors: Cholongitas Evangelos , Papatheodoridis George V. , Lahanas Alexandros , Xanthaki Anna , Kontou‐Kastellanou Chrysoula , Archimandritis Athanasios J. 
Published: February 2005

Abstract: Aim: To evaluate the characteristics and possible recent changes of the microbial causes of spontaneous bacterial peritonitis (SBP) in cirrhotic patients.Methods: We retrospectively evaluated 42 cirrhotic patients with positive ascitic fluid culture and without evidence of secondary peritonitis who were admitted consecutively to our Department between 1998 and 2002.Results: Twenty (48%) of 42 patients with positive ascitic fluid culture were diagnosed during 1998–1999 (period A) and the remaining 22 (52%) patients during 2000–2002 (period B). Gram‐negative bacteria were the cause of SBP in 15 (75%) of the 20 patients during period A and in only nine (41%) of the 22 patients during period B (P=0.026). SBP patients with Gram‐positive bacteria compared with those with Gram‐negative bacteria were less frequently in Child class C (P=0.058) and had significantly higher ascitic fluid protein (P=0.014) and albumin concentrations (P=0.009) and lower ascitic fluid neutrophil count (P=0.008). Resistance to quinolones was detected significantly more frequently in the isolated Gram‐positive than Gram‐negative bacteria (P<0.001).Conclusion: Culture‐positive SBP in cirrhotic patients are caused more frequently by Gram‐positive bacteria during the recent years, which are, in their vast majority, resistant to quinolones.
AI4OPT: AI Institute for Advances in Optimization
Authors: Van Hentenryck Pascal , Dalmeijer Kevin 
Published: February 2024

AbstractThis article is a short introduction toAI4OPT, the NSF AI Institute for Advances in Optimization.AI4OPTfuses AI and optimization, inspired by societal challenges in supply chains, energy systems, chip design and manufacturing, and sustainable food systems. By combining machine learning and mathematical optimization,AI4OPTstrives to develop AI‐assisted optimization systems that bring orders of magnitude improvements in efficiency, perform accurate uncertainty quantification, and address challenges in resiliency and sustainability.AI4OPTalso applies its “teaching the teachers” philosophy to provide longitudinal educational pathways in AI for engineering.
Mitigated Oxygen Loss in Lithium‐Rich Manganese‐Based Cathode Enabled by Strong Zr–O Affinity
Authors: Wang Guan , Xie Chenghao , Wang Hong , Li Quan , Xia Fanjie , Zeng Weihao , Peng Haoyang , Van Tendeloo Gustaaf , Tan Gangjian , Tian Jinsai , Wu Jinsong 
Published: February 2024

AbstractOxygen loss is a serious problem of lithium‐rich layered oxide (LLO) cathodes, as the high capacity of LLO relies on reversible oxygen redox. Oxygen release can occur at the surface leading to the formation of spinel or rock salt structures. Also, the lattice oxygen will usually become unstable after long cycling, which remains a major roadblock in the application of LLO. Here, it is shown that Zr doping is an effective strategy to retain lattice oxygen in LLO due to the high affinity between Zr and O. A simple sol‐gel method is used to dope Zr4+into the LLOs to adjust the local electronic structure and inhibit the diffusion of oxygen anions to the surface during cycling. Compared with untreated LLOs, LLO–Zr cathodes exhibit a higher cycling stability, with 94% capacity retention after 100 cycles at 0.4 C, up to 223 mAh g−1at 1 C, and 88% capacity retention after 300 cycles. Theoretical calculations show that due to the strong Zr–O covalent bonding, the formation energy of oxygen vacancies has effectively increased and the loss of lattice oxygen under high voltage can be suppressed. This study provides a simple method for developing high‐capacity and cyclability Li‐rich cathode materials for lithium‐ion batteries.
A Self‐Powered Wound Dressing Based on “Lock‐ON/OFF” Drug Release Combined Electric Stimulus Therapy for Accelerated Infected Wound Healing
Authors: Sun Yani , Tang Yufei , He Yuxuan , Chen Lei , Wu Cong , Zhang Bo , Yan Fuxue , Zhao Kang , Wu Zixiang 
Published: February 2024

AbstractTo facilitate the on‐demand release of hydrophilic antibiotics for accelerated repair of infected wounds, a self‐powered wound dressing incorporating a “Lock‐ON/OFF” electric field (EF)‐driven drug release mechanism combined with electrical stimulation (ES) therapy is presented. When subjected to mechanical stress, the drug exhibits controlled, slow‐release behavior, achieving a remarkable cumulative release rate of 88.57%—89 times higher than the non‐mechanical stress group. Conversely, in the absence of mechanical stress, the drug remains unreleased, maintaining a 0% cumulative release rate in a fully closed state. The dressing utilizes its piezoelectric effect to establish an electric field, enabling precise control of hydrophilic drug release by regulating the electrostatic balance between the drug carrier and the drug. Moreover, the piezoelectric field acts as an exogenous electric field, remodeling the endogenous electric field of the wound, and accelerating wound closure. Combining EF‐driven drug release with ES result in a 1.26 fold improvement in wound healing compared to ES alone. This study addresses precision therapy limitations in fully automated diagnosis and treatment, paving the way for advancements in remote diagnosis, wireless therapy, and on‐demand precision medicine.
Optical Microlithography of Perovskite Quantum Dots/Organic Semiconductor Heterojunctions for Neuromorphic Photosensors
Authors: Wu Yue , Dai Shilei , Liu Xu , Guo Pu , Zhang Junyao , Sun Tongrui , Guo Ziyi , Xu Yutong , Liang Haixia , Xiong Lize , Hu Huawei , Huang Jia 
Published: February 2024

AbstractHeterojunctions of perovskite quantum dots (QDs) and organic semiconductors (OSCs) can synergistically leverage the unique optoelectronic properties of different functional components to fabricate advanced optoelectronic devices, such as neuromorphic photosensors, by low‐cost solution processes. However, a long‐lasting challenge remains in micropatterning high‐density perovskite QDs/polymer OSCs heterojunction array with high yield and reliability due to the fragility of functional layers to organic solvents. High‐density and micro‐structure patterned organic neuromorphic photosensor arrays based on OSCs and QDs are thus rarely reported. Here, an effective cross‐linking microlithography strategy is reported to fabricate perovskite QDs/OSCs microstructure arrays. The fabricated CsPbBr3 QDs/(poly(2,5‐(2‐octyldodecyl)−3,6‐diketopyrrolopyrrole‐alt‐5,5‐(2,5‐di(thien‐2‐yl) thieno [3,2‐b] thiophene) (DPPDTT) planer heterojunctions phototransistor array presents minor device‐to‐device variation, high density (6500 devices cm−2), and high yield (almost 100%). The device array exhibits impressive merits as a neuromorphic photosensor, including a photosensitivity of 3.02 × 107, a responsivity up to 1.92 × 104 A W−1, a detectivity exceeding 1014 Jones, and a persistent photoconductivity. Moreover, an energy consumption as low as 27.9 aJ is achieved at an operating voltage of −0.0001 V. The potential application of the heterojunction neuromorphic photosensor array in motion perception is demonstrated in conjunction with a neural network.
TiO2 Nano‐Biopatterning Reveals Optimal Ligand Presentation for Cell–Matrix Adhesion Formation
Authors: Jain Kashish , Pandey Ashish , Wang Hao , Chung Taerin , Nemati Arash , Kanchanawong Pakorn , Sheetz Michael P. , Cai Haogang , Changede Rishita 
Published: February 2024

AbstractNanoscale organization of transmembrane receptors is critical for cellular functions, enabled by the nanoscale engineering of bioligand presentation. Previously, a spatial threshold of ≤60 nm for integrin binding ligands in cell–matrix adhesion is demonstrated using monoliganded gold nanoparticles. However, the ligand geometric arrangement is limited to hexagonal arrays of monoligands, while plasmonic quenching limits further investigation by fluorescence‐based high‐resolution imaging. Here, these limitations are overcome with dielectric TiO2 nanopatterns, eliminating fluorescence quenching, thus enabling super‐resolution fluorescence microscopy on nanopatterns. By dual‐color super‐resolution imaging, high precision and consistency among nanopatterns, bioligands, and integrin nanoclusters are observed, validating the high quality and integrity of both nanopattern functionalization and passivation. By screening TiO2 nanodiscs with various diameters, an increase in fibroblast cell adhesion, spreading area, and Yes‐associated protein (YAP) nuclear localization on 100 nm diameter compared with smaller diameters was observed. Focal adhesion kinase is identified as the regulatory signal. These findings explore the optimal ligand presentation when the minimal requirements are sufficiently fulfilled in the heterogenous extracellular matrix network of isolated binding regions with abundant ligands. Integration of high‐fidelity nano‐biopatterning with super‐resolution imaging allows precise quantitative studies to address early signaling events in response to receptor clustering and their nanoscale organization.
Bioresorbable Multilayer Organic–Inorganic Films for Bioelectronic Systems
Authors: Hu Ziying , Guo Hexia , An Dongqi , Wu Mingzheng , Kaura Anika , Oh Hannah , Wang Yue , Zhao Mengjia , Li Shuo , Yang Quansan , Ji Xudong , Li Shupeng , Wang Bo , Yoo Davin , Tran Phuong , Ghoreishi‐Haack Nayereh , Kozorovitskiy Yevgenia , Huang Yonggang , Li Rui , Rogers John A. 
Published: February 2024

AbstractBioresorbable electronic devices as temporary biomedical implants represent an emerging class of technology relevant to a range of patient conditions currently addressed with technologies that require surgical explantation after a desired period of use. Obtaining reliable performance and favorable degradation behavior demands materials that can serve as biofluid barriers in encapsulating structures that avoid premature degradation of active electronic components. Here, this work presents a materials design that addresses this need, with properties in water impermeability, mechanical flexibility, and processability that are superior to alternatives. The approach uses multilayer assemblies of alternating films of polyanhydride and silicon oxynitride formed by spin‐coating and plasma‐enhanced chemical vapor deposition , respectively. Experimental and theoretical studies investigate the effects of material composition and multilayer structure on water barrier performance, water distribution, and degradation behavior. Demonstrations with inductor‐capacitor circuits, wireless power transfer systems, and wireless optoelectronic devices illustrate the performance of this materials system as a bioresorbable encapsulating structure.
Mechanically Robust Self‐Organized Crack‐Free Nanocellular Graphene with Outstanding Electrochemical Properties in Sodium Ion Battery
Authors: Park Wong‐Young , Han Jiuhui , Moon Jongun , Joo Soo‐Hyun , Wada Takeshi , Ichikawa Yuji , Ogawa Kazuhiro , Kim Hyoung Seop , Chen Mingwei , Kato Hidemi 
Published: February 2024

AbstractCrack‐free nanocellular graphenes are attractive materials with extraordinary mechanical and electrochemical properties, but their homogeneous synthesis on the centimeter scale is challenging. Here, a strong nanocellular graphene film achieved by the self‐organization of carbon atoms using liquid metal dealloying and employing a defect‐free amorphous precursor is reported. This study demonstrates that a Bi melt strongly catalyzes the self‐structuring of graphene layers at low processing temperatures. The robust nanoarchitectured graphene displays a high‐genus seamless framework and exhibits remarkable tensile strength (34.8 MPa) and high electrical conductivity (1.6 × 104 S m−1). This unique material has excellent potential for flexible and high‐rate sodium‐ion battery applications.