A Diet Enriched with Curcumin Impairs Newly Acquired and Reactivated Fear Memories

Curcumin, a yellow-pigment compound found in the popular Indian spice turmeric (Curcuma longa), has been extensively investigated for its anti-inflammatory, chemopreventative, and antidepressant properties. Here, we examined the efficacy of dietary curcumin at impairing the consolidation and reconsolidation of a Pavlovian fear memory, a widely studied animal model of traumatic memory formation in posttraumatic stress disorder (PTSD). We show that a diet enriched with 1.5% curcumin prevents the training-related elevation in the expression of the immediate early genes (IEGs) Arc/Arg3.1 and Egr-1 in the lateral amygdala (LA) and impairs the ‘consolidation'' of an auditory Pavlovian fear memory; short-term memory (STM) is intact, whereas long-term memory (LTM) is significantly impaired. Next, we show that dietary curcumin impairs the ‘reconsolidation'' of a recently formed auditory Pavlovian fear memory; fear memory retrieval (reactivation) and postreactivation (PR)-STM are intact, whereas PR-LTM is significantly impaired. Additional experiments revealed that dietary curcumin is also effective at impairing the reconsolidation of an older, well-consolidated fear memory. Furthermore, we observed that fear memories that fail to reconsolidate under the influence of dietary curcumin are impaired in an enduring manner; unlike extinguished fear memories, they are not subject to reinstatement or renewal. Collectively, our findings indicate that a diet enriched with curcumin is capable of impairing fear memory consolidation and reconsolidation processes, findings that may have important clinical implications for the treatment of disorders such as PTSD that are characterized by unusually strong and persistently reactivated fear memories.     

Physical activity and the risk of non-Hodgkin lymphoma subtypes: A pooled analysis

Non-Hodgkin lymphoma (NHL) is composed of a heterogeneous collection of subtypes with considerable differences in genetics, biology and aetiology. Studies to date on physical activity and NHL risk have not had sufficient sample size to evaluate whether associations differ by subtype. We pooled data from nine case-control studies to examine the association between moderate-to-vigorous intensity physical activity (MVPA) and risk of NHL overall and by subtype (diffuse large B-cell lymphoma, follicular lymphoma, chronic lymphocytic leukaemia/small lymphocytic lymphoma, marginal zone lymphoma and mature T-cell lymphoma). A total of 5653 cases and 9115 controls were included in the pooled analysis. Physical activity was harmonised across nine studies and modelled as study-specific tertiles. Multinomial logistic regression was used to estimate the association between physical activity and NHL, adjusting for confounders. The overall odds of NHL was 13% lower among participants in the most active tertile of MVPA compared to the least active tertile (adjusted odds ratio = 0.87, 95% CI = 0.80, 0.95). Similar decreases were observed across NHL subtypes. In summary, in this pooled analysis of case-control studies, physical activity was associated with a modest risk reduction for each NHL subtype examined and with overall NHL.     

Underpotential lithium plating on graphite anodes caused by temperature heterogeneity

Rechargeability and operational safety of commercial lithium (Li)-ion batteries demand further improvement. Plating of metallic Li on graphite anodes is a critical reason for Li-ion battery capacity decay and short circuit. It is generally believed that Li plating is caused by the slow kinetics of graphite intercalation, but in this paper, we demonstrate that thermodynamics also serves a crucial role. We show that a nonuniform temperature distribution within the battery can make local plating of Li above 0 V vs. Li⁰/Li⁺ (room temperature) thermodynamically favorable. This phenomenon is caused by temperature-dependent shifts of the equilibrium potential of Li⁰/Li⁺. Supported by simulation results, we confirm the likelihood of this failure mechanism during commercial Li-ion battery operation, including both slow and fast charging conditions. This work furthers the understanding of nonuniform Li plating and will inspire future studies to prolong the cycling lifetime of Li-ion batteries.

Lithium (Li)-ion batteries with graphite anodes and Li metal oxide cathodes are the dominant commercial battery chemistry for electric vehicles (EVs) (1). However, their cycle lifetime and operational stability still demand further improvements (2–5). During long-term cycling, Li-ion batteries undergo irreversible capacity decay due to decreased utilization of anode/cathode active materials, metallic Li plating, electrolyte dry-out, impedance build-up, or excessive heat generation (6–9). Some of these issues also lead to battery shorting and thermal runaway (10, 11). To enable mass adoption of EVs, increasing efforts have been made to realize the fast charging of Li-ion batteries (12). Under this condition, all of the detrimental factors mentioned above are aggravated (6, 7, 13), further compromising the battery cycling life and safety. As a result, a clear understanding of the failure mechanisms of Li-ion batteries is crucial for their future development.Plating of metallic Li on graphite anodes is a major cause of the capacity decay of Li-ion batteries (6, 7, 12, 14–17). Significant amounts of solid electrolyte interphase (SEI) and dead Li form and remain inactive, leading to an accelerated loss of Li inventory. It is generally believed that the slow kinetics of Li ion intercalation into graphite causes metallic Li plating (14). Three-electrode measurements (18–25) showed that the potential of graphite anodes shifted negatively under increased charging rates and finally dropped below 0 V vs. Li⁰/Li⁺, reaching Li-plating conditions. However, Li-plating phenomenon on graphite anodes is still not fully understood. Firstly, the actual onset potential of Li plating is still unclear, which is not necessarily below 0 V vs. Li⁰/Li⁺ (18). Furthermore, few studies explained why Li plated on graphite in spatially inhomogeneous patterns (7, 14, 17). Most importantly, in some reports, Li plates even under a moderate charging rate below 1.5 C (6, 7). Under these conditions, three-electrode measurements indicate that the anode potential does not drop below 0 V vs. Li⁰/Li⁺ (18). Kinetic arguments alone are not sufficient to resolve these problems, so we hypothesize that previously neglected thermodynamic factors may also play crucial roles in Li plating.It is well-known that the equilibrium electrode potential of a redox reaction shifts with temperature (26–35). Exothermic reactions and joule heating during cycling raise the temperature of batteries (10), which can also build up an internal temperature gradient. Simulations (7, 36–42) and experimental studies (41, 43–49) showed intensified heating under increased cycling rates, and temperature differences of 2 K to nearly 30 K within the batteries (10). This spatial variation in temperature leads to a heterogeneous distribution of the equilibrium potential for both Li plating and graphite intercalation on the anode, which could make Li plating thermodynamically favorable at certain locations.In this paper, we discover that temperature heterogeneities within Li-ion batteries can cause Li plating by shifting its equilibrium electrode potential. We first introduce a method to quantify the temperature dependence of the equilibrium potential for both Li plating and graphite intercalation. Then, we correlate the shift of the equilibrium potential to Li plating using a Li-graphite coin cell with an intentionally created heterogeneous temperature distribution and explain the observation with thermal and electrochemical simulations. Finally, the effects under fast charging conditions are examined. The data explicitly show that metallic Li can plate above 0 V vs. Li⁰/Li⁺ (room temperature) on a graphite anode. The temperature dependence of the equilibrium potential likely participates in the capacity decay of commercial Li-ion batteries, which can be increasingly severe during fast charging conditions. This research brings insights into a key failure mechanism of Li-ion batteries, highlights the importance of maintaining homogeneous temperature within batteries, and will inspire future development of Li-ion batteries with improved safety and cycle lifetime.     

A Convenient Method for Guarding Against Localized Mucositis During Radiation Therapy

Metal restorations, such as full gold crowns and dental implants, can cause forward and back scatter radiation during radiation therapy with a dose enhancement to adjacent tissues. Mucositis, one of the most common complications of the radiation treatment of oral, as well as other head and neck malignancies can result. A method for constructing a buccolingual guard in the clinical setting using hydroplastic material is described. The guard can be easily oriented and adapted to an existing radiation stent, adding positional stability and patient comfort. When adequate thickness of material is used, the guard can attenuate forward and back scatter radiation, separate the adjacent tissues from metal restorations, and protect the oral mucosa from localized incidents of mucositis.