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Ultrasmall Ag^＋-rich nanoclusters as highly efficient nanoreservoirs for bacterial killing

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Nano Research 2014年第3期7卷 301-307页

作者： Xun Yuan magdiel i. setyawati David T. Leong Jianping Xie Department of Chemical and Biomolecular Engineering National University of Singapore 4 Engineering Drive 4 117576 Singapore

Metallic silver （Ag） and its ability to combat infection have been known since ancient history. in the wake of nanotechnology advancement, silver＇s efficacy to fight broad spectrum bacterial infections is further improved in the form of Ag nanoparticles （NPs）. Recent studies have ascribed the broad spectrum antimicrobial properties of Ag NPs to dissociation of Ag＊ ions from the NPs, which may not be entirely applicable when the size of Ag NPs decreases to the sub-2 nm range [denoted Ag nanoclusters （NCs）]. in this paper we report that ultrasmall glutathione （GSH）-protected Ag^＋-rich NCs （Ag^＋-R NCs for short, with a predominance of Ag＋ species in the NCs） have much higher antimicrobial activities towards both gram-negative and gram-positive bacteria than the reference NC, GSH-Ag^＋-R NCs. They have the same size and surface ligand, but with different oxidation states of the core silver. This interesting finding suggests that the undissociated Ag^＋-R NCs armed with abundant Ag^＋ ions on the surface are highly active in bacterial killing, which was not observed in the system of their larger counterpart, Ag NPs.

关键词： noble metal nanoclusters silver antimicrobial agent biomedicine bacteria

Presentation matters： identity of gold nanocluster capping agent governs intracellular uptake and cell metabolism

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Nano Research 2014年第6期7卷 805-815页

作者： Chor Yong Tay Yong Yu magdiel inggrid setyawati Jianping Xie David Tai Leong Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117585 Singapore NUS Graduate School for integrative Sciences and Engineering National University of Singapore 28 Medical Drive Singapore 117456 Singapore

Au nanoclusters （AuNCs） hold tremendous potential to be employed in a wide variety of biological applications. Despite the rapid development in the field of NCs synthesis, a comprehensive understanding of how cells interact with this class of ultra-small nanoparticles （〈2 nm） having defined sizes and surface chemistry, remains poorly understood. in this study, we show that the choice of the surface ligand used to protect AuNCs can significantly perturb cellular uptake and intracellular redox signaling. A panel of monodisperse, atomically precise AuNCs with different core Au atom number （i.e., Auls, Au18 and Au25） protected with either mercaptopropionic acid （MPA） or glutathione （GSH） capping agent were synthesized and their effects on the generation of intracellular reactive oxygen species （ROS）, cytotoxicity and genotoxicity of the NCs were assessed. Both mitochondrial superoxide anion （O2^-） and cytoplasmic ROS were found to be higher in cells exposed to MPA but not GSH capped AuNCs. The unregulated state of intracellular ROS is correlated to the amount of internalized AuNCs. interestingly, MPA-AuNCs induction of ROS level did not lead to any detrimental cellular effects such as cell death or DNA damage. instead, it was observed that the increase in redox status corresponded to higher cellular metabolism and proliferative capacity. Our study illustrates that surface chemistry of AuNCs plays a pivotal role in affecting the biological outcomes and the new insights gained will be useful to form the basis of defining specific design rules to enable rational engineering of ultra-small complex nanostructures for biological applications.

关键词： nanotechnology nanobiology gold nanoclusters reactive oxygen species surface chemistry

Creation of an oxygen-enriched environment during synthesis as an effective way to improve luminescent properties of Y_(2)O_(3):Eu^(3+)

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Journal of Rare Earths 2025年第1期43卷 21-29,I0001页

作者： Aleksandr A.Nashivochnikov Anton i.Kostyukov Mariana i.Rakhmanova Lidiya S.Kibis Svetlana V.Cherepanova Evgenii A.Suprun Novosibirsk State University Pirogova Str.2630090NovosibirskRussia Boreskov institute of Catalysis SB RAS 5 Lavrentiev Ave630090NovosibirskRussia Nikolaev institute of inorganic Chemistry SB RAS 3 Lavrentiev Ave630090NovosibirskRussia

The growing demand for luminescent nanomaterials intended for various applications increases the necessity to develop and improve approaches to the creation of highly efficient nanosized *** current study,an approach to enhancing the efficiency of red luminescence of monoclinic Y_(2)O_(3):Eu^(3+)with the particle size of~20 nm by creating the oxygen-enriched environment during the gas-phase synthesis was *** investigate the effect of oxygen amount during the synthesis on characteristics of the phosphor,a series of nano structured Y_(2)O_(3):Eu^(3+)with the addition of 0-40 vol%O_(2) to the main buffer gas Ar was synthesized by laser *** is shown that the amount of added O_(2) exerts virtually no effect on the phase composition and particle size,but significantly improves the luminescent characteristics of Y_(2)O_(3):Eu^(3+).Thus,the addition of 30 vol%O_(2) leads to virtually a 20-fold growth in the photoluminescence(PL)intensity caused by ^(5)D_(0)→^(7)F_(0-4) transitions in Eu^(3+)and an increase in the absolute PL quantum yield from 3%to 53%(λex=395 nm)compared to the sample synthesized without O_(2).The addition of oxygen also improves the emission color coordinates from(0.571,0.320)to(0.630,0.322)due to the removal of a considerable fraction of oxygen *** synthesized nanopowders are shown to be highly stable:upon storage under ambient conditions for two *** yield(QY)of the samples decreases by less than 2%.it is expected that the key features underlying the proposed approach will be useful for various methods used to synthesize oxide nanophosphors.

关键词： Photoluminescence Quantum yield Laservaporization Y_(2)0_(3):Eu^(3+) Monoclinic Y_(2)0_(3) Rareearths

Arctic sea-ice extent: No record minimum in 2023 or recent years

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Atmospheric and Oceanic Science Letters 2025年第1期18卷 52-55页

作者： Ola M.Johannessen Tor i.Olaussen Nansen Scientific Society BergenNorway Nansen Environmental and Remote Sensing Center BergenNorway

Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(***^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 ***^(2), 0.794 ***^(2) less than the minimum in 2023. However, the ice extent had decreased by 0.432 ***^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. in general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.

关键词： Sea ice Arctic Minimum ice Climate

Bacteria and host: what does this mean for sepsis bottleneck?

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World Journal of Emergency Medicine 2025年第1期16卷 10-17页

作者： Azzah S Alharbi Raghad Hassan Sanyi Esam i Azhar Department of Clinical Microbiology and immunology Faculty of MedicineKing Abdulaziz UniversityJeddah 21362Saudi Arabia Special infectious Agent Unit King Fahad Medical Research CenterKing Abdulaziz UniversityJeddah 21362Saudi Arabia College of Health and Medical Technology Middle Technical UniversityBaghdad 10047Iraq Department of Medical Laboratory Sciences Faculty of Applied Medical SciencesKing Abdulaziz UniversityJeddah 21362Saudi Arabia

BACKGROUND: Sepsis is a life-threatening inflammatory condition in which the invading pathogen avoids the host's defense mechanisms and continuously stimulates and damages host cells. Consequently, many immune responses initially triggered for protection become harmful because of the failure to restore homeostasis, resulting in ongoing hyperinflammation and immunosuppression. METHODS: A literature review was conducted to address bacterial sepsis, describe advances in understanding complex immunological reactions, critically assess diagnostic approaches, and emphasize the importance of studying bacterial bottlenecks in the detection and treatment of ***: Diagnosing sepsis via a single laboratory test is not feasible;therefore, multiple key biomarkers are typically monitored, with a focus on trends rather than absolute values. The immediate interpretation of sepsis-associated clinical signs and symptoms, along with the use of specific and sensitive laboratory tests, is crucial for the survival of patients in the early stages. However, long-term mortality associated with sepsis is now recognized, and alongside the progression of this condition, there is an in vivo selection of adapted ***: Bacterial sepsis remains a significant cause of mortality across all ages and societies. While substantial progress has been made in understanding the immunological mechanisms underlying the inflammatory response, there is growing recognition that the ongoing host-pathogen interactions, including the emergence of adapted virulent strains, shape both the acute and long-term outcomes in sepsis. This underscores the urgent need for novel high-throughput diagnostic methods and a shift toward more pre-emptive, rather than reactive, treatment strategies in sepsis care.

关键词： Sepsis Bacteria Bottleneck inflammation

The effect of oral lead acetate exposure on bax expression and apoptosis index granulose cells antral follicle in female wistar rat (Rattus norvegicus)

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Asian pacific Journal of Reproduction 2017年第2期6卷 54-57页

作者： Dian Aby Restanty setyawati Soeharto i Wayan Agung indrawan State Health Polytechnic of Ministry Malang Jl.Besar Ijen 77CMalangEast Java65612Indonesia Division of Pharmacology Science Faculty of MedicineBrawijaya UniversityJl.Veteran MalangEast Java65145Indonesia Division of Obstetrics Gynecology of Faculty of Medicine Brawijaya UniversityJl.Veteran MalangEast Java65145Indonesia Dr.Saiful Anwar Hospital Jl.Jaksa Agung Suprapto No.2MalangEast Java65112Indonesia

Objective:To prove the effect of administered orally lead acetate exposure on Bax expression and the apoptosis index of granulosa cells on antral follicle female albino rats Wistar strain (Rattus norvegicus).Methods:Post-test only control group, using female albino rats Wistar strain aged (10-12) wk (reproductive age) weighing (100-200) g. Twenty-four animal samples were classified into one control group and three groups exposed to lead acetate in doses of 30, 100, and 300 ppm, respectively. Lead acetate was administered orally through a feeding tube over 30 d. Bax expression of granulosa cells on antral follicle was checked using immunohistochemistry, and apoptosis index were examined using Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL).Results:Lead increases apoptosis index on doses of 300 ppm. The increase of the Bax expression granulosa cell on antral follicle was not statistically ***:The exposure of lead acetate administrated orally can increase apoptosis index of granulosa cell on antral follicle although it doesn't affect Bax expression.

关键词： Lead acetate Bax Apoptosis

Overcoming bacterial physical defenses with molecule-like ultrasmall antimicrobial gold nanoclusters

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Bioactive Materials 2021年第4期6卷 941-950页

作者： Kaiyuan Zheng magdiel isetyawati David Tai Leong Jianping Xie Department of Chemical and Biomolecular Engineering National University of Singapore4 Engineering Drive 4117585Singapore School of Materials Science and Engineering Nanyang Technological University50 Nanyang Avenue639798Singapore

The size of metal nanoparticles(NPs)is crucial in their biomedical *** abundant studies on the size effects of metal NPs in the range of 2-100 nm have been conducted,the exploration of the ultrasmall metal nanoclusters(NCs)of~1 nm in size with unique features is quite *** synthesize three different sized gold(Au)NCs of different Au atom numbers and two bigger sized Au NPs protected by the same ligand to study the size influence on antimicrobial *** ultrasmall Au NCs can easily traverse the cell wall pores to be internalized inside bacteria,inducing reactive oxygen species generation to oxidize bacterial membrane and disturb bacterial *** explains why the Au NCs are antimicrobial while the Au NPs are non-antimicrobial,suggesting the key role of size in antimicrobial ***,in contrast to the widely known size-dependent antimicrobial properties,the Au NCs of different atom numbers demonstrate molecule-like instead of size-dependent antimicrobial behavior with comparable effectiveness,indicating the unique molecule-like feature of ultrasmall Au *** the bacterial defenses at the wall with ultrasmall Au NCs changes what was previously believed to harmless to the bacteria instead to a highly potent agent against the bacteria.

关键词： Gold nanoclusters Gold nanoparticles Antimicrobial agents Molecule-like properties Size effects

Viscosity,NMR Diffusometry and Light Scattering Data for Aqueous and Aqueous-Salt Solutions of Poly(1-butyl-3-vinylimidazolium bromide)

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Chinese Journal of Polymer Science 2025年第2期43卷 380-391页

作者： Petr A.Korchak Polina S.Yarchenko Evgenia A.Safonova Alina S.Koneva Alexey i.Victorov St.Petersburg State University St.Petersburg 199034Russia

Poly(1-butyl-3-vinylimidazolium bromide)is a polymerized ionic liquid(PiLs),a relatively new class of materials that combines the attractive properties of ionic liquids(iLs)and polyelectrolytes and finds wide *** backbone of this PiL is composed of quaternary imidazolium salts,which are among the most promising and popular ***,little is known about the physicochemical characteristics of the aqueous solutions of this *** this study,we synthesized and characterized samples of this PiL and obtained experimental data on the viscosity,static and dynamic light scattering,and nuclear magnetic resonance diffusometry for aqueous and aqueous KBr solutions with varying polymer contents at T=298.15 *** discuss the effects of the polymer concentration and salinity on the behavior of the solution.

关键词： Polymerized ionic liquid Polyelectrolyte solutions Viscosity Light scattering NMR diffusometry

Multisensory mechanisms of gait and balance in Parkinson’s disease:an integrative review

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Neural Regeneration Research 2025年第1期20卷 82-92页

作者： Stiven Roytman Rebecca Paalanen Giulia Carli Uros Marusic Prabesh Kanel Teus van Laar Nico i.Bohnen Department of Radiology University of MichiganAnn ArborMIUSA Department of Neurology University of MichiganAnn ArborMIUSA Morris K.Udall Center of Excellence for Parkinson’s Disease Research University of MichiganAnn ArborMIUSA institute for Kinesiology Research Science and Research Centre KoperKoperSlovenia Department of Health Sciences Alma Mater Europaea–ECMMariborSlovenia Parkinson’s Foundation Research Center of Excellence University of MichiganAnn ArborMIUSA Department of Neurology University of GroningenUniversity Medical Center GroningenGroningenThe Netherlands Neurology Service and GRECC VA Ann Arbor Healthcare SystemAnn ArborMIUSA

Understanding the neural underpinning of human gait and balance is one of the most pertinent challenges for 21st-century translational neuroscience due to the profound impact that falls and mobility disturbances have on our aging *** and gait control does not happen automatically,as previously believed,but rather requires continuous involvement of central nervous *** effectively exert control over the body,the brain must integrate multiple streams of sensory information,including visual,vestibular,and somatosensory *** mechanisms which underpin the integration of these multisensory signals are the principal topic of the present *** multisensory integration theories focus on how failure of cognitive processes thought to be involved in multisensory integration leads to falls in older *** emphasis,however,has been placed on specific contributions of individual sensory modalities to multisensory integration processes and cross-modal interactions that occur between the sensory modalities in relation to gait and *** the present work,we review the contributions of somatosensory,visual,and vestibular modalities,along with their multisensory intersections to gait and balance in older adults and patients with Parkinson’s *** also review evidence of vestibular contributions to multisensory temporal binding windows,previously shown to be highly pertinent to fall risk in older ***,we relate multisensory vestibular mechanisms to potential neural substrates,both at the level of neurobiology(concerning positron emission tomography imaging)and at the level of electrophysiology(concerning electroencephalography).We hope that this integrative review,drawing influence across multiple subdisciplines of neuroscience,paves the way for novel research directions and therapeutic neuromodulatory approaches,to improve the lives of older adults and patients with neurodegenerative diseases.

关键词： aging balance encephalography functional magnetic resonance imaging gait multisensory integration Parkinson’s disease positron emission tomography somatosensory vestibular visual