Prolonged Lifespan Research Articles

Salvianolic acid B alleviates autoimmunity in Treg-deficient mice via inhibiting IL2-STAT5 signaling.

Regulatory T cell (Treg) deficiency leads to immune dysregulation, polyendocrinopathy, enteropathy, and X-linked (IPEX) syndrome, which is a CD4+ T cell-driven autoimmune disease in both humans and mice. Despite understanding the molecular and cellular characteristics of IPEX syndrome, new treatment options have remained elusive. Here, we hypothesized that salvianolic acid B (Sal B), one of the main active ingredients of Salvia miltiorrhiza, can protect against immune disorders induced by Treg deficiency. To examine whether Sal B can inhibit Treg deficiency-induced autoimmunity, Treg-deficient scurfy (SF) mice with a mutation in forkhead box protein 3 were treated with different doses of Sal B. Immune cells, inflammatory cell infiltration, and cytokines were evaluated by flow cytometry, hematoxylin and eosin staining and enzyme-linked immunosorbent assay Kits, respectively. Moreover, RNA sequencing, western blot, and real-time PCR were adopted to investigate the molecular mechanisms of action of Sal B. Sal B prolonged lifespan and reduced inflammation in the liver and lung of SF mice. Moreover, Sal B decreased plasma levels of several inflammatory cytokines, such as IL-2, IFN-γ, IL-4, TNF-α, and IL-6, in SF mice. By analyzing the transcriptomics of livers, we determined the signaling pathways, especially the IL-2-signal transducer and activator of transcription 5 (STAT5) signaling pathway, which were associated with Treg deficiency-induced autoimmunity. Remarkably, Sal B reversed the expression of gene signatures related to the IL-2-STAT5 signaling pathway in vitro and in vivo. Sal B prolongs survival and inhibits lethal inflammation in SF mice through the IL-2-STAT5 axis. Our findings may inspire novel drug discovery efforts aimed at treating IPEX syndrome.

A singlet oxygen-storing covalent organic framework for “Afterglow” photodynamic therapy

Photodynamic therapy (PDT) is an emerging treatment but often restricted by the availability of oxygen. Enhancing the lifespan of singlet oxygen (1O2) by fractionated generation is an effective approach to improve the efficacy of PDT. Herein, an imine-based nanoscale COF (TpDa-COF) has been synthesized and functionalized with a pyridone-derived structure (Py) to create a 1O2-storing nanoplatform TpDa-COF@Py, which can reversibly capture and release 1O2. Under 660 nm laser exposure, Py interacts with 1O2 produced by the porphyrin motif in COF backbones to generate 1O2-enriched COF (TpDa-COF@Py + hv), followed by the release of 1O2 through retro-Diels-Alder reactions at physiological temperatures. The continuous producing and releasing of 1O2 upon laser exposure leads to an “afterglow” effect and a prolonged 1O2 lifespan. In vitro cytotoxicity assays demonstrates that TpDa-COF@Py + hv exhibits an extremely low half-maximal inhibitory concentration (IC50) of 0.54 µg/mL on 4T1 cells. Remarkably, the Py-mediated TpDa-COF@Py nanoplatform demonstrates enhanced cell-killing capability under laser exposure, attributed to the sustained 1O2 cycling, compared to TpDa-COF alone. Further in vivo assessment highlights the potential of TpDa-COF@Py + hv as a promising strategy to enhance phototheronostics and achieve effective tumor regression. Accordingly, the study supplies a generalized 1O2 “afterglow” nanoplatform to improve the effectiveness of PDT.

The brain microvasculature is a primary mediator of interferon-α neurotoxicity in human cerebral interferonopathies

Aicardi-Goutières syndrome (AGS) is an autoinflammatory disease characterized by aberrant interferon (IFN)-α production. The major cause of morbidity in AGS is brain disease, yet the primary source and target of neurotoxic IFN-α remain unclear. Here, we demonstrated that the brain was the primary source of neurotoxic IFN-α in AGS and confirmed the neurotoxicity of intracerebral IFN-α using astrocyte-driven Ifna1 misexpression in mice. Using single-cell RNA sequencing, we demonstrated that intracerebral IFN-α-activated receptor (IFNAR) signaling within cerebral endothelial cells caused a distinctive cerebral small vessel disease similar to that observed in individuals with AGS. Magnetic resonance imaging (MRI) and single-molecule ELISA revealed that central and not peripheral IFN-α was the primary determinant of microvascular disease in humans. Ablation of endothelial Ifnar1 in mice rescued microvascular disease, stopped the development of diffuse brain disease, and prolonged lifespan. These results identify the cerebral microvasculature as a primary mediator of IFN-α neurotoxicity in AGS, representing an accessible target for therapeutic intervention.

Comparative study of fiber materials for enhanced performance of hybrid cooling in battery thermal management systems

Battery thermal management systems play a crucial role in maintaining the optimal temperature range of lithium-ion batteries, ensuring their efficient operation and prolonged lifespan. Hybrid cooling (HC) techniques, which involve the utilization of hydrophilic fibers, have shown promise in enhancing the thermal performance of these systems. The present study employs an experimental approach to investigate the impact of selected fiber materials on the thermal performance of a hybrid cooling system designed for battery thermal management. Parameters such as the time required for complete wetting of the fiber and the coolant absorption capacity of the fiber are considered during the fiber selection process. Findings reveal that the tissue paper fiber displayed superior water transfer capabilities, achieving a minimum wetting time of 46 s for a 75 mm fiber length. This characteristic positions it as a promising candidate for the subsequent hybrid cooling experiment. Noteworthy is its water holding capacity per unit volume, which surpassed that of cotton fiber by 40%. HC demonstrates the superior temperature uniformity and average battery pack temperature compared to simple air cooling (SAC) under varying velocities, emphasizing the pivotal role of HC. A remarkable improvement of 41.86% in temperature uniformity is obtained in HC over SAC.

Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

The lithium metal anode is hailed as the desired “holy grail” for the forthcoming generation of high-energy-density batteries, given its astounding theoretical capacity and low potential. Nonetheless, the formation and growth of dendrites seriously compromise battery life and safety. Herein, an yttria-stabilized bismuth oxide (YSB) layer is fabricated on the polypropylene (PP) separator, where YSB reacts with Li anode in-situ in the cell to form a multi-component composite interlayer consisting of Li3Bi, Li2O, and Y2O3. The interlayer can function not only as a redistributor to regulate Li+ distribution but also as an anion adsorber to increase the Li+ transference number from 0.37 to 0.79 for suppressing dendrite nucleation and growth. Consequently, compared with the cell with a baseline separator, those with modified separators exhibit prolonged lifespan in both Li/Li symmetrical cells and Li/Cu half-cells. Notably, the full cells coupled with ultrahigh-loading LiFePO4 display an excellent cycling performance of 1700 cycles with a high capacity retention of ∼80% at 1 C, exhibiting great potential for practical applications. This work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free Li anode and realizing long-lifespan lithium metal batteries.

CoN//Co9S8 co-embedded in reduced graphene oxide as catalyst for catalytic conversion of polysulfides

Lithium-sulfur (Li–S) batteries with high theoretical specific capacity of 1675 mAh g−1 and energy density of 2600 Wh kg−1 are considered as a promising candidate for energy conversion and storage devices in future. However, some critical dilemmas such as low real energy density, high solubility of ether-based electrolytes and slow redox kinetics of long-chain polysulfides remain unsettled hindering their development. Here we design and propose a high-performance sulfur host material constructed by growing CoN/Co9S8 nanoparticles enclosed in reduced graphene oxide (RGO) and Co9S8 modified separator to enhance the electrochemical performance of Li–S batteries. The results of first principal calculations confirm that the calculated adsorption energies of Li2S8, Li2S6, Li2S4 and Li2S2 on the Co9S8 (111) surface are lower than that of the CoN (111) surface, indicating that the Co9S8 has stronger adsorbing effect with polysulfides. Furthermore, the catalytic effect in Li2S6 symmetric batteries and the nucleation of the Li2S tests display that the CoN/Co9S8@RGO has a fast conversion reaction kinetics and catalytic effect of polysulfides, thereby inhibiting the leakage of the polysulfides. Consequently, the S@CoN/Co9S8@RGO cathode with Co9S8 layer represents a high discharge capacity of 1367.7 mAh g−1 at 0.1C and a prolonged lifespan over 700 cycles at 1 C with an extremely low decay rate of 0.06 % per cycle and high cycling stability.

LRRK2 Kinase Inhibitor PF-06447475 Protects Drosophila melanogaster against Paraquat-Induced Locomotor Impairment, Life Span Reduction, and Oxidative Stress

Parkinson’s disease (PD) is a complex multifactorial progressive neurodegenerative disease characterized by locomotor alteration due to the specific deterioration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNpc). Mounting evidence shows that human LRRK2 (hLRRK2) kinase activity is involved in oxidative stress (OS)-induced neurodegeneration, suggesting LRRK2 inhibition as a potential therapeutic target. We report that the hLRRK2 inhibitor PF-06447475 (PF-475) prolonged lifespan, increased locomotor activity, maintained DAergic neuronal integrity, and reduced lipid peroxidation (LPO) in female Drosophila melanogaster flies chronically exposed to paraquat (PQ), a redox cycling compound, compared to flies treated with vehicle only. Since LRRK2 is an evolutionary conserved kinase, the present findings reinforce the idea that either reduction or inhibition of the LRRK2 kinase might decrease OS and locomotor alterations associated with PD. Our observations highlight the importance of uncovering the function of the hLRRK2 orthologue dLrrk2 in D. melanogaster as an excellent model for pharmacological screenings.

Design and implementation of a high misalignment-tolerance wireless charger for an electric vehicle with control of the constant current/voltage charging

Wireless charging of Electric Vehicles (EVs) has been extensively researched in the realm of electric cars, offering a convenient method. Nonetheless, there has been a scarcity of experiments conducted on low-power electric vehicles. To establish a wireless power transfer system for an electric vehicle, optimal power and transmission efficiency necessitate arranging the coils coaxially. In wireless charging systems, coils often experience angular and lateral misalignments. In this paper, a new alignment strategy is introduced to tackle the misalignment problem between the transmitter and receiver coils in the wireless charging of Electric Vehicles (EVs). The study involves the design and analysis of a coil, considering factors such as mutual inductance and efficiency. Wireless coils with angular misalignment are modelled in Ansys Maxwell simulation software. The proposed practical EV system aims to align the coils using angular motion, effectively reducing misalignment during the parking of two-wheelers. This is achieved by tilting the transmitter coil in the desired direction. Furthermore, micro sensing coils are employed to identify misalignment and facilitate automatic alignment. Additionally, adopting a power control technique becomes essential to achieve both constant current (CC) and constant voltage (CV) modes during battery charging. Integrating CC and CV modes is crucial for efficiently charging lithium-ion batteries, ensuring prolonged lifespan and optimal capacity utilization. The developed system can improve the efficiency of the wireless charging system to 90.3% with a 24 V, 16 Ah Lithium Ion Phosphate (LiFePO4) battery at a 160 mm distance between the coils.

A cation and anion dual-doping strategy in novel Li-rich Mn-based cathode materials for high-performance Li metal batteries

Lithium (Li)-rich Manganese (Mn)-based cathode materials are considered to be the most hopeful cathode materials for next-generation high-energy-density Li metal batteries. However, the rapid capacity fading and voltage decaying derived from phase transformation still hinder their practical application. Herein, we developed a cation/anion dual-doping strategy by synchronically incorporating Zr4+ cation and F− anion to boost the structural stability of the Li-rich Mn-based cathode. The strengthened transition metal-oxygen bonds raised by doping effect can inhibit the release of oxygen for enhanced electrochemical reversibility and mitigate the anisotropic lattice distortion to stabilize the layered structure. Meanwhile, dual doping strategy expands the lattice distance and increases oxygen vacancy formation energy, thereby improving ion diffusion kinetics and structural stability. As a result, the obtained cathode presents an excellent initial discharge capacity of 268.5 mAh g−1 and a prolonged cycle lifespan beyond 300 cycles. A stable cycling performance can be obtained under a high areal capacity of 5.17 mAh cm−2 with a low negative/positive electrode capacity ratio of 1.93. Our dual-doping strategy provides a valuable new idea for improving the structural stability and electrochemical properties of Li-rich Mn-based cathode materials, further promoting the development of high-energy-density Li metal batteries.

Significantly improved electrical conductivity and cycling stability of manganese dioxide by poly (3,4-ethylene-dioxythiophene) coating

Abstract Manganese dioxide (MnO2) is widely acknowledged as a prospective pseudocapacitive material aimed at alleviating the issue of low energy density in supercapacitors. Nevertheless, hampered by its intrinsic low conductivity and poor structural stability, MnO2-based energy storage materials often exhibit lower practical capacity in practical applications. During this investigation, the synthesis of MnO2@PEDOT (poly(3,4-ethylenedioxythiophene)) composite materials involved an in-situ oxidative polymerization approach, whereby PEDOT nanowires were integrated onto the MnO2 nanoparticle surface. Notably, the internal configuration of the MnO2@PEDOT composite material demonstrated a high surface area morphology, while the externally entwined PEDOT nanowire layer further expanded the material’s specific surface area. As a result, the MnO2@PEDOT composite material demonstrated a specific capacitance reaching 214 F g-1, a 91% improvement compared to unmodified MnO2. Furthermore, the winding of PEDOT nanowires effectively suppressed the structural disintegration of MnO2. The MnO2@PEDOT composite material exhibited a remarkable improvement in cycling stability, maintaining 81% of its initial capacity after 5000 cycles. The electron-rich PEDOT not only improved the conductivity of the inner MnO2 through electron migration but also prevented MnO2 structural degradation by tightly enveloping it. The outcomes of our study propose a method for constructing MnO2 featuring a structurally stable configuration and a prolonged cycling lifespan, offering valuable insights for designing electrode materials with high cycling stability in supercapacitors.

Stabilizing dual-cation liquid metal battery for large-scale energy storage: A comprehensive hybrid design approach

Liquid metal batteries (LMBs) hold immense promise for large-scale energy storage. However, normally LMBs are based on single type of cations (e.g., Ca2+, Li+, Na+), and as a result subject to inherent limitations associated with each type of single cation, such as the low energy density in Ca-based LMBs, the high energy cost in Li-based LMBs, and the short cycling lifespan in Na-based LMBs. Here we propose a dual-cation (Ca2+ and Li+) liquid metal battery, which allows access to, simultaneously, high energy density, prolonged cycling lifespan, reduced energy cost, and enhanced cycling stability. For this strategy to work, the main obstacle to overcome is the instability of the dual-cation system in electrochemical reactions. We have undertaken a hybrid design approach to resolve this issue, by integrating phase diagram design, first-principles calculations, and machine learning techniques. We discover that incorporating magnesium as an inert additive can effectively stabilize the cycling performance of dual-cation LMBs. Furthermore, our results reveal that specific ion ratios are required to release tailor dual-cation chemistry, to enable the designed multi-component alloy (Ca-Li-Mg in our case) electrode to function properly in LMBs. These findings are expected to have general implications for future developments of innovative LMBs with enhanced performance.

Enhanced hydrogen peroxide electrosynthesis and prolonged lifespan by preparing gas diffusion electrode via electrodeposition of CB on Ni foam

In-situ hydrogen peroxide (H2O2) production is pivotal for the effective implementation of the electro-Fenton reaction. However, challenges such as low H2O2 yields and a short electrode lifespan have hindered its application. This study introduced a novel gas diffusion electrode (GDE), the CB(E)-Ni foam(GDE), fabricated through a combination of carbon black (CB) electrodeposition and polytetrafluoroethylene (PTFE) impregnation techniques. Comprehensive physicochemical characterizations and electrochemical evaluations indicated that CB was more uniformly dispersed across the Ni foam, enhancing its electrochemical activity. When employed as a cathode, the CB(E)-Ni foam(GDE) demonstrated superior two-electron oxygen reduction reaction (2e− ORR) capabilities, marked by increased oxygen utilization and reduced energy demands, achieving a remarkable H2O2 concentration of 897.73 mg/L after 120 min. This performance significantly outpaces that of traditional GDEs. The unique structure of the CB(E)-Ni foam(GDE) not only prolonged electrode life by preventing rapid deactivation but also boosted H2O2 production and oxygen efficiency by 31.78% and 31.79%, respectively, when compared to a standard non-GDE configuration. In practical applications, the CB(E)-Ni foam(GDE) demonstrated utility by facilitating an 84.1% degradation rate of fulvic acid over 120 min within a homogeneous electro-Fenton system, highlighting its potential for environmental remediation.

Biomimetic Superstructured Interphase for Aqueous Zinc-Ion Batteries.

The practical application of aqueous zinc-ion batteries (AZIBs) is greatly challenged by rampant dendrites and pestilent side reactions resulting from an unstable Zn-electrolyte interphase. Herein, we report the construction of a reliable superstructured solid electrolyte interphase for stable Zn anodes by using mesoporous polydopamine (2D-mPDA) platelets as building blocks. The interphase shows a biomimetic nacre's "brick-and-mortar" structure and artificial transmembrane channels of hexagonally ordered mesopores in the plane, overcoming the mechanical robustness and ionic conductivity trade-off. Experimental results and simulations reveal that the -OH and -NH groups on the surface of artificial ion channels can promote rapid desolvation kinetics and serve as an ion sieve to homogenize the Zn2+ flux, thus inhibiting side reactions and ensuring uniform Zn deposition without dendrites. The 2D-mPDA@Zn electrode achieves an ultralow nucleation potential of 35 mV and maintains a Coulombic efficiency of 99.8% over 1500 cycles at 5 mA cm-2. Moreover, the symmetric battery exhibits a prolonged lifespan of over 580 h at a high current density of 20 mA cm-2. This biomimetic superstructured interphase also demonstrates the high feasibility in Zn//VO2 full cells and paves a new route for rechargeable aqueous metal-ion batteries.

HIV-Associated Hypertension: Risks, Mechanisms, and Knowledge Gaps.

HIV type 1 (HIV-1) is the causative agent of AIDS. Since the start of the epidemic, HIV/AIDS has been responsible for ≈40 million deaths. Additionally, an estimated 39 million people are currently infected with the virus. HIV-1 primarily infects immune cells, such as CD4+ (cluster of differentiation 4+) T lymphocytes (T cells), and as a consequence, the number of CD4+ T cells progressively declines in people living with HIV. Within a span of ≈10 years, HIV-1 infection leads to the systemic failure of the immune system and progression to AIDS. Fortunately, potent antiviral therapy effectively controls HIV-1 infection and prevents AIDS-related deaths. The efficacy of the current antiviral therapy regimens has transformed the outcome of HIV/AIDS from a death sentence to a chronic disease with a prolonged lifespan of people living with HIV. However, antiviral therapy is not curative, is challenged by virus resistance, can be toxic, and, most importantly, requires lifelong adherence. Furthermore, the improved lifespan has resulted in an increased incidence of non-AIDS-related morbidities in people living with HIV including cardiovascular diseases, renal disease, liver disease, bone disease, cancer, and neurological conditions. In this review, we summarize the current state of knowledge of the cardiovascular comorbidities associated with HIV-1 infection, with a particular focus on hypertension. We also discuss the potential mechanisms known to drive HIV-1-associated hypertension and the knowledge gaps in our understanding of this comorbid condition. Finally, we suggest several directions of future research to better understand the factors, pathways, and mechanisms underlying HIV-1-associated hypertension in the post-antiviral therapy era.

Bimetallic MOFs-Derived NiFe2O4/Fe2O3 Enabled Dendrite-free Lithium Metal Anodes with Ultra-High Area Capacity Based on An Intermittent Lithium Deposition Model.

In practical operating conditions, the lithium deposition behavior is often influenced by multiple coupled factors and there is also a lack of comprehensive and long-term validation for dendrite suppression strategies. Our group previously proposed an intermittent lithiophilic model for high-performance three-dimensional (3D) composite lithium metal anode (LMA), however, the electrodeposition behavior was not discussed. To verify this model, this paper presents a modified 3D carbon cloth (CC) backbone by incorporating NiFe2O4/Fe2O3 (NFFO) nanoparticles derived from bimetallic NiFe-MOFs. Enhanced Li adsorption capacity and lithiophilic modulation were achieved by bimetallic MOFs-derivatives which prompted faster and more homogeneous Li deposition. The intermittent model was further verified in conjunction with the density functional theory (DFT) calculations and electrodeposition behaviors. As a result, the obtained Li-CC@NFFO||Li-CC@NFFO symmetric batteries exhibit prolonged lifespan and low hysteresis voltage even under ultra-high current and capacity conditions (5 mA cm-2, 10 mAh cm-2), what's more, the full battery coupled with a high mass loading (9 mg cm-2) of LiFePO4 cathode can be cycled at a high rate of 5 C, the capacity retention is up to 95.2 % before 700 cycles. This work is of great significance to understand the evolution of lithium dendrites on the 3D intermittent lithiophilic frameworks.

Superhalide-Anion-Motivator Reforming-Enabled Bipolar Manipulation toward Longevous Energy-Type Zn||Chalcogen Batteries.

Neutrophilic superhalide-anion-triggered chalcogen conversion-based Zn batteries, despite latent high-energy merit, usually suffer from a short lifespan caused by dendrite growth and shuttle effect. Here, a superhalide-anion-motivator reforming strategy is initiated to simultaneously manipulate the anode interface and Se conversion intermediates, realizing a bipolar regulation toward longevous energy-type Zn batteries. With ZnF2 chaotropic additives, the original large-radii superhalide zincate anion species in ionic liquid (IL) electrolytes are split into small F-containing species, boosting the formation of robust solid electrolyte interphases (SEI) for Zn dendrite inhibition. Simultaneously, ion radius reduced multiple F-containing Se conversion intermediates form, enhancing the interion interaction of charged products to suppress the shuttle effect. Consequently, Zn||Se batteries deliver a ca. 20-fold prolonged lifespan (2000 cycles) at 1 A g-1 and high energy/power density of 416.7 Wh kgSe-1/1.89 kW kgSe-1, outperforming those in F-free counterparts. Pouch cells with distinct plateaus and durable cyclability further substantiate the practicality of this design.

Highly Stretchable Polyurethane Porous Membranes with Adjustable Morphology for Advanced Lithium Metal Batteries.

A highly flexible, tunable morphology membrane with excellent thermal stability and ionic conductivity can endow lithium metal batteries with high power density and reduced dendrite growth. Herein, a porous Polyurethane (PU) membrane with an adjustable morphology was prepared by a simple nonsolvent-induced phase separation technique. The precise control of the final morphology of PU membranes can be achieved through appropriate selection of a nonsolvent, resulting a range of pore structures that vary from finger-like voids to sponge-like pores. The implementation of combinatorial DFT and experimental analysis has revealed that spongy PU porous membranes, especially PU-EtOH, show superior electrolyte wettability (472%), high porosity (75%), good mechanical flexibility, robust thermal dimensional stability (above 170 °C), and elevated ionic conductivity (1.38 mS cm-1) in comparison to the polypropylene (PP) separator. The use of PU-EtOH in Li//Li symmetric cell results in a prolonged lifespan of 800 h, surpasing the longevity of PU or PP cells. Moreover, when subjected to a high rate of 5 C, the LiFePO4/Li half-cell with a PU-EtOH porous membrane displayed better cycling performance (115.4 mAh g-1) compared to the PP separator (104.4 mAh g-1). Finally, the prepared PU porous membrane exhibits significant potential for improving the efficiency and safety of LMBs.

Biosynthesis of photostable CdS quantum dots by UV-resistant psychrotolerant bacteria isolated from Union Glacier, Antarctica.

Quantum Dots (QDs) are fluorescent nanoparticles with exceptional optical and optoelectronic properties, finding widespread utility in diverse industrial applications. Presently, chemically synthesized QDs are employed in solar cells, bioimaging, and various technological domains. However, many applications demand QDs with prolonged lifespans under conditions of high-energy radiation. Over the past decade, microbial biosynthesis of nanomaterials has emerged as a sustainable and cost-effective process. In this context, the utilization of extremophile microorganisms for synthesizing QDs with unique properties has recently been reported. In this study, UV-resistant bacteria were isolated from one of the most extreme environments in Antarctica, Union Glacier at the Ellsworth Mountains. Bacterial isolates, identified through 16S sequencing, belong to the genera Rhodococcus, Pseudarthrobacter, and Arthrobacter. Notably, Rhodococcus sp. (EXRC-4A-4), Pseudarthrobacter sp. (RC-2-3), and Arthrobacter sp. (EH-1B-1) tolerate UV-C radiation doses ≥ 120J/m². Isolated UV-resistant bacteria biosynthesized CdS QDs with fluorescence intensities 4 to 8 times higher than those biosynthesized by E. coli, a mesophilic organism tolerating low doses of UV radiation. Transmission electron microscopy (TEM) analysis determined QD sizes ranging from 6 to 23nm, and Fourier-transform infrared (FTIR) analysis demonstrated the presence of biomolecules. QDs produced by UV-resistant Antarctic bacteria exhibit high photostability after exposure to UV-B radiation, particularly in comparison to those biosynthesized by E. coli. Interestingly, red fluorescence-emitting QDs biosynthesized by Rhodococcus sp. (EXRC-4A-4) and Arthrobacter sp. (EH-1B-1) increased their fluorescence emission after irradiation. Analysis of methylene blue degradation after exposure to irradiated QDs biosynthesized by UV-resistant bacteria, indicates that the QDs transfer their electrons to O2 for the formation of reactive oxygen species (ROS) at different levels. UV-resistant Antarctic bacteria represent a novel alternative for the sustainable generation of nanostructures with increased radiation tolerance-two characteristics favoring their potential application in technologies requiring continuous exposure to high-energy radiation.

Kinetic Evaluation on Lithium Polysulfide in Weakly Solvating Electrolyte toward Practical Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are highly considered as next-generation energy storage techniques. Weakly solvating electrolyte with low lithium polysulfide (LiPS) solvating power promises Li anode protection and improved cycling stability. However, the cathodic LiPS kinetics is inevitably deteriorated, resulting in severe cathodic polarization and limited energy density. Herein, the LiPS kinetic degradation mechanism in weakly solvating electrolytes is disclosed to construct high-energy-density Li-S batteries. Activation polarization instead of concentration or ohmic polarization is identified as the dominant kinetic limitation, which originates from higher charge-transfer activation energy and a changed rate-determining step. To solve the kinetic issue, a titanium nitride (TiN) electrocatalyst is introduced and corresponding Li-S batteries exhibit reduced polarization, prolonged cycling lifespan, and high actual energy density of 381 Wh kg-1 in 2.5 Ah-level pouch cells. This work clarifies the LiPS reaction mechanism in protective weakly solvating electrolytes and highlights the electrocatalytic regulation strategy toward high-energy-density and long-cycling Li-S batteries.

Response of tropical forest productivity to seasonal drought mediated by potassium and phosphorus availability

Tropical forest productivity is increasingly reported to be nutrient limited, which may affect its response to seasonal droughts. Yet experimental evidence on nutrient limitation from Afrotropical forests remains rare. We conducted an ecosystem-scale, full factorial nitrogen (N)–phosphorus (P)–potassium (K) addition experiment in a moist forest in Uganda to investigate nutrient controls on fine litter production and foliar chemistry. The eight factorial treatments were replicated four times in 32 plots of 40 × 40 m each. During the three-year nutrient additions, we found K and P limitations on leaf litter production, exhibiting strong links to ecosystem responses to seasonal drought. Specifically, leaf litterfall consistently decreased in dry seasons with K additions, whereas P additions caused a reduction only during prolonged drought in the first year. Leaf litterfall was not significantly affected by N additions. Furthermore, K additions delayed the timing of leaf litterfall peak, underscoring the crucial role of K in regulating stomatal aperture and signalling during water-stress conditions and suggesting a prolonged leaf lifespan. Foliar N increased with N and P additions whereas K was the most resorbed nutrient. We conclude that the productivity and resilience of tropical forests, particularly under drier conditions, may depend on terrestrial K and P availability.