Inverse kinetic isotope effects in the charge transfer reactions of ammonia with rare gas ions

In the absence of experimental data, models of complex chemical environments rely on predicted reaction properties. Astrochemistry models, for example, typically adopt variants of capture theory to estimate the reactivity of ionic species present in interstellar environments. In this work, we examine astrochemically-relevant charge transfer reactions between two isotopologues of ammonia, NH3 and ND3, and two rare gas ions, Kr+ and Ar+. An inverse kinetic isotope effect is observed; ND3 reacts faster than NH3. Combining these results with findings from an earlier study on Xe+ (Petralia et al., Nat. Commun., 2020, 11, 1), we note that the magnitude of the kinetic isotope effect shows a dependence on the identity of the rare gas ion. Capture theory models consistently overestimate the reaction rate coefficients and cannot account for the observed inverse kinetic isotope effects. In all three cases, the reactant and product potential energy surfaces, constructed from high-level ab initio calculations, do not exhibit any energetically-accessible crossing points. Aided by a one-dimensional quantum-mechanical model, we propose a possible explanation for the presence of inverse kinetic isotope effects in these charge transfer reaction systems.

Altered distributions in circulating follicular helper and follicular regulatory T cells accountable for imbalanced cytokine production in multiple sclerosis

Follicular T helper (Tfh) and regulatory (Tfr) cells are distinct subsets of CD4+ T lymphocytes, regulating humoral immune responses in the germinal center. It is widely accepted that dysregulated Tfh and Tfr cells are associated with autoimmunity. In this study, we evaluated the frequencies of circulating chemokine receptor (CXCR)5+ programmed cell death 1 (PD-1+ ) Tfh (cTfh) and CXCR5+ PD-1+ forkhead box protein 3 (FoxP3+ ) CD25+ Tfr (cTfr) cells, and their corresponding cytokines from the peripheral blood mononuclear cells of 28 patients with relapsing-remitting multiple sclerosis (MS) and 16 age- and sex-matched healthy controls (HC). Subsets of cTfh cells by Th1- and Th17-related surface markers (CXCR3 and CCR6) were also evaluated. We found that the frequency of cTfh cells was significantly higher in MS patients compared to that of HC. Conversely, the frequency of cTfr cells was lower in MS patients than that of HC. Interleukin (IL)-21-producing cTfh cells were significantly increased in MS patients, while IL-10-secreting cTfr cells were lower in MS patients compared to levels in HC. Among cTfh cells, cTfh17.1 cells were the major subtypes that were significantly increased in MS patients compared to HC, with the frequency of IL-21-secreting cells being the highest. These results suggest that an imbalanced distribution of cTfh and cTfr exist in MS patients, which contributes to the reciprocally altered IL-21 and IL-10 production.

Zn2+-Imidazole Coordination Crosslinks for Elastic Polymeric Binders in High-Capacity Silicon Electrodes

Recent research has built a consensus that the binder plays a key role in the performance of high-capacity silicon anodes in lithium-ion batteries. These anodes necessitate the use of a binder to maintain the electrode integrity during the immense volume change of silicon during cycling. Here, Zn2+-imidazole coordination crosslinks that are formed to carboxymethyl cellulose backbones in situ during electrode fabrication are reported. The recoverable nature of Zn2+-imidazole coordination bonds and the flexibility of the poly(ethylene glycol) chains are jointly responsible for the high elasticity of the binder network. The high elasticity tightens interparticle contacts and sustains the electrode integrity, both of which are beneficial for long-term cyclability. These electrodes, with their commercial levels of areal capacities, exhibit superior cycle life in full-cells paired with LiNi0.8Co0.15Al0.05O2 cathodes. The present study underlines the importance of highly reversible metal ion-ligand coordination chemistries for binders intended for high capacity alloying-based electrodes.

FoxO1 as a Regulator of Aquaporin 5 Expression in the Salivary Gland

Forkhead box O1 (FoxO1) is a multifunctional initiator, mediator, and repressor of autoimmune diseases in an organ- or disease-specific manner. However, the role of FoxO1 in the salivary gland has not yet been elucidated. In this study, we discovered that FoxO1 and aquaporin 5 (AQP5) are both significantly downregulated in the patients with primary Sjögren syndrome, an autoimmune disease accompanying salivary gland dysfunction. Pharmacologic or genetic perturbation of FoxO1 in the rat salivary gland acinar cell line, SMG-C6, induced a significant downregulation of AQP5 expression, as observed in clinical specimens. There was a strong correlation between FoxO1 and AQP5 expression because FoxO1 is a direct regulator of AQP5 expression in salivary gland acinar cells through its interaction with the promoter region of AQP5. Serial injection of a FoxO1 inhibitor into mice induced a reduction of AQP5 expression in submandibular glands and, consequently, hyposalivation, which is one of the major clinical symptoms of primary Sjögren syndrome. However, there was no sign of inflammation or cell damage in the submandibular glands harvested from mice treated with the FoxO1 inhibitor. In conclusion, our findings indicate that FoxO1 in salivary gland tissue acts as a direct regulator of AQP5 expression. Thus, downregulation of FoxO1 observed in primary Sjögren syndrome is a putative mechanism for hyposalivation without the involvement of previously reported soluble factors in primary Sjögren syndrome patient sera.

A Brief Online and Offline (Paper-and-Pencil) Screening Tool for Generalized Anxiety Disorder: The Final Phase in the Development and Validation of the Mental Health Screening Tool for Anxiety Disorders (MHS: A)

Generalized anxiety disorder (GAD) can cause significant socioeconomic burden and daily life dysfunction; hence, therapeutic intervention through early detection is important. This study was the final stage of a 3-year anxiety screening tool development project that evaluated the psychometric properties and diagnostic screening utility of the Mental Health Screening Tool for Anxiety Disorders (MHS: A), which measures GAD. A total of 527 Koreans completed online and offline (i.e., paper-and pencil) versions of the MHS: A, Beck Anxiety Inventory (BAI), Generalized Anxiety Disorder-7 (GAD-7), and Penn State Worry Questionnaire (PSWQ). The participants had an average age of 38.6 years and included 340 (64.5%) females. Participants were also administered the Mini-International Neuropsychiatric Interview (MINI). Internal consistency, convergent/criterion validity, item characteristics, and test information were assessed based on the item response theory (IRT), and a factor analysis and cut-off score analyses were conducted. The MHS: A had good internal consistency and good convergent validity with other anxiety scales. The two versions (online/offline) of the MHS: A were nearly identical (r = 0.908). It had a one-factor structure and showed better diagnostic accuracy (online/offline: sensitivity = 0.98/0.90, specificity = 0.80/0.83) for GAD detection than the GAD-7 and BAI. The IRT analysis indicated that the MHS: A was most informative as a screening tool for GAD. The MHS: A can serve as a clinically useful screening tool for GAD in Korea. Furthermore, it can be administered both online and offline and can be flexibly used as a brief mental health screener, especially with the current rise in telehealth.

Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

A first measurement of the longitudinal beam spin asymmetry A_{LU} in the semi-inclusive electroproduction of pairs of charged pions is reported. A_{LU} is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A_{LU}^{sinϕ_{R}} moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.

CERKL is upregulated in cutaneous squamous cell carcinoma and maintains cellular sphingolipids and resistance to oxidative stress

BACKGROUND

Ceramide kinase-like protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism.

OBJECTIVES

To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress.

METHODS

CERKL expression was determined by RNA-Seq, quantitative polymerase chain reaction and immunohistochemistry. CERKL was knocked down in cSCC cells using small interfering RNA. Sphingolipid content was analysed by liquid chromatography-mass spectrometry. Oxidative stress was induced by treatment with H₂ O₂ , and apoptosis was measured using flow cytometry to determine annexin V binding.

RESULTS

CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL is also expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress.

CONCLUSIONS

These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.