Understanding the Reactivity of a Thin Li1.5Al0.5Ge1.5(PO4)3 Solid‐State Electrolyte toward Metallic Lithium Anode

The thickness of solid‐state electrolytes (SSEs) significantly affects the energy density and safety performance of all‐solid‐state lithium batteries. However, a sufficient understanding of the reactivity toward lithium metal of ultrathin SSEs (<100 µm) based on NASICON remains lacking. Herein, for the first time, a self‐standing and ultrathin (70 µm) NASICON‐type Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) electrolyte via a scalable solution process is developed, and X‐ray photoelectron spectroscopy reveals that changes in LAGP at the metastable Li–LAGP interface during battery operation is temperature dependent. Severe germanium reduction and decrease in LAGP particle size are detected at the Li–LAGP interface at elevated temperature. Oriented plating of lithium metal on its preferred (110) face occurs during in situ X‐ray diffraction cycling.     

Dihydropyrazolopyrimidine Inhibitors of KV1.5 (IKur)

A series of dihydropyrazolopyrimidine inhibitors of K_V1.5 (I_Kur) have been identified. The synthesis, structure–activity relationships and selectivity against several other ion channels are described.     

Electron spin-lattice relaxation of the [Cu(1.5) ... Cu(1.5)] dinuclear copper center in nitrous oxide reductase.

Relaxation times have been obtained with time-domain EPR for the dinuclear mixed valence [CuA(1.5) ... CuA(1.5)[ S = 1/2 center in nitrous oxide reductase, N2OR, from Pseudomonas stutzeri, in the TN5 mutant defective in copper chromophore biosynthesis, in a synthetic mixed valence complex, and in type 1 and 2 copper complexes. Data confirmed that the intrinsic electron spin-lattice relaxation time, T1, for N2OR in the temperature range of 6-25 K is unusually short for copper centers. At best, a twofold increase of T1 from g perpendicular to g parallel was measured. Optimized fits of the saturation-recovery data were obtained using both double-exponential and stretched-exponential functions. The temperature dependence of the spin-lattice relaxation rate of mutant N2OR is about T5.0 with the stretched-exponential model or T3.3 and T3.9 for the model using the sum of two exponentials. These T1s are intrinsic to the mixed valence [CuA(1.5) ... CuA(1.5)] center, and no interaction of the second copper center in wild-type N2OR with the [CuA(1.5) ... CuA(1.5)] center has been observed. The T1 of the mixed valence center of N2OR is not only shorter than for monomeric square planar Cu(II) complexes, but also shorter than for a synthetic mixed valence complex, Cu2(N[CH2CH2NHCH2CH2NHCH2CH2]3N). The short T1 is attributed to the vibrational modes of type 1 copper and/or the metal-metal interaction in [CuA(1.5) ... CuA(1.5)].     

Stereoselective block of a human cardiac potassium channel (Kv1.5) by bupivacaine enantiomers.

Stereoselective drug-channel interactions may help to elucidate the molecular basis of voltage-gated potassium channel block by local anesthetic drugs. We studied the effects of the enantiomers of bupivacaine on a cloned human cardiac potassium channel (hKv1.5). This channel was stably expressed in a mouse Ltk- cell line and studied using the whole-cell configuration of the patch-clamp technique. Both enantiomers modified the time course of this delayed rectifier current. Exposure to 20 microM of either S(-)-bupivacaine or R(+)-bupivacaine did not modify the activation time constant of the current, but reduced the peak outward current and induced a subsequent exponential decline of current with time constants of 18.7 +/- 1.1 and 10.0 +/- 0.9 ms, respectively. Steady-state levels of block (assessed with 250-ms depolarizing pulses to +60 mV) averaged 30.8 +/- 2.5% (n = 6) and 79.5 +/- 3.2% (n = 6) (p < 0.001), for S(-)- and R(+)-bupivacaine, respectively. The concentration dependence of hKv1.5 inhibition revealed apparent KD values of 27.3 +/- 2.8 and 4.1 +/- 0.7 microM for S(-)-bupivacaine and R(+)-bupivacaine, respectively, with Hill coefficients close to unity, suggesting that binding of one enantiomer molecule per channel was sufficient to block potassium permeation. Analysis of the rate constants of association (k) and dissociation (l) yielded similar values for l (24.9 s-1 vs. 23.6 s-1 for S(-)- and R(+)-bupivacaine, respectively) but different association rate constants (1.0 x 10(6) vs. 4.7 x 10(6) M-1 s-1 for S(-)- and R(+)-bupivacaine, respectively). Block induced by either enantiomer displayed a shallow voltage dependence in the voltage range positive to 0 mV, i.e., where the channel is fully open, consistent with an equivalent electrical distance delta of 0.16 +/- 0.01. This suggested that at the binding site, both enantiomers of bupivacaine experienced 16% of the applied transmembrane electrical field, referenced to the inner surface. Both bupivacaine enantiomers reduced the tail current amplitude recorded on return to -40 mV and slowed their time course relative to control, resulting in a "crossover" phenomenon.(ABSTRACT TRUNCATED AT 400 WORDS)     

Lithium and hematopoiesis.

Some of lithium''s effects on blood cell formation suggest that the element may be of value in treating hematologic disorders. Lithium enhances granulopoiesis and thereby induces neutrophilia. Two possible mechanisms of action are suggested: a direct action on the pluripotent stem cells, or an inhibition of the suppressor cells (thymus-dependent lymphocytes) that limit hematopoiesis. Lithium also inhibits erythropoiesis. Although most studies use concentrations at or above pharmacologic levels there is evidence that lithium plays a role in normal cell metabolism.     

A (1.5 + epsilon)-approximation algorithm for unsigned translocation distance

Genome rearrangement is an important area in computational biology and bioinformatics. The translocation operation is one of the popular operations for genome rearrangement. It was proved that computing the unsigned translocation distance is NP-hard. In this paper, we present a (1.5 + epsilon)-approximation algorithm for computing unsigned translocation distance which improves upon the best known 1.75-ratio. The running time of our algorithm is O(n2 + (4/epsilon)1.5 square root log(4/epsilon )2(4/epsilon), where n is the total number of genes in the genome.