The predicted crystal structure of Li_4C_6O_6, an organic cathode material for Li-ion batteries, from first-principles multi-level computational methods

In this communication, we use first-principles based multi-level computational methods to predict the crystal structure of Li_4C_6O_6, the key intermediate material that can be oxidized to Li_2C_6O_6 or reduced to Li_6C_6O_6. This predicted structure leads to an X-ray diffraction (XRD) pattern in good agreement with experiment, validating the predicted structure. With this structure in hand one can proceed to determine details for the electrochemical properties of these organic electrodes (chemical potential for Li ion as a function of loading and the mechanism for the lithiation/delithiation process) useful in designing optimum systems

Cell Labeling and Tracking Method without Distorted Signals by Phagocytosis of Macrophages

Cell labeling and tracking are important processes in understanding biologic mechanisms and the therapeutic effect of inoculated cells in vivo. Numerous attempts have been made to label and track inoculated cells in vivo; however, these methods have limitations as a result of their biological effects, including secondary phagocytosis of macrophages and genetic modification. Here, we investigated a new cell labeling and tracking strategy based on metabolic glycoengineering and bioorthogonal click chemistry. We first treated cells with tetra-acetylated N-azidoacetyl-D-mannosamine to generate unnatural sialic acids with azide groups on the surface of the target cells. The azide-labeled cells were then transplanted to mouse liver, and dibenzyl cyclooctyne-conjugated Cy5 (DBCO-Cy5) was intravenously injected into mice to chemically bind with the azide groups on the surface of the target cells in vivo for target cell visualization. Unnatural sialic acids with azide groups could be artificially induced on the surface of target cells by glycoengineering. We then tracked the azide groups on the surface of the cells by DBCO-Cy5 in vivo using bioorthogonal click chemistry. Importantly, labeling efficacy was enhanced and false signals by phagocytosis of macrophages were reduced. This strategy will be highly useful for cell labeling and tracking

Inhibition of elongin C promotes longevity and protein homeostasis via HIF-1 in C.elegans.

open17

The Reaction Mechanism and Capacity Degradation Model in Lithium Insertion Organic Cathodes, Li_2C_6O_6, Using Combined Experimental and First Principle Studies

Herein, we explore the capacity degradation of dilithium rhodizonate salt (Li_2C_6O_6) in lithium rechargeable batteries based on detailed investigations of the lithium de/insertion mechanism in Li_2C_6O_6 using both electrochemical and structural ex situ analyses combined with first-principles calculations. The experimental observations indicate that the Li_xC_6O_6 electrode undergoes multiple two-phase reactions in the composition range of 2 ≤ x ≤ 6; however, the transformations in the range 2 ≤ x ≤ 4 involve a major morphological change that eventually leads to particle exfoliation and the isolation of active material. Through first-principles analysis of Li_xC_6O_6 during de/lithiation, it was revealed that particle exfoliation is closely related to the crystal structural changes with lithium deinsertion from C_6O_6 interlayers of the Li_xC_6O_6. Among the lithium ions found at various sites, the extraction of lithium from C_6O_6 interlayers at 2 ≤ x ≤ 4 decreases the binding force between the C_6O_6 layers, promoting the exfoliation of C_6O_6 layers and pulverization at the electrode, which degrades capacity retention

Retroperitoneal Giant Liposarcoma

Retroperitoneal liposarcoma is an infrequent, locally aggressive malignancy. We report two cases of huge retroperitoneal liposarcomas. The presence of a palpable abdominal mass was a common symptom of the two patients. Preoperative imaging study showed huge retroperitoneal tumors. Both patients underwent complete surgical resections, and a negative microscopic margin was achieved in both cases. The histopathologic diagnosis was a well-differentiated retroperitoneal liposarcoma. Neither of the two patients developed a recurring tumor during the 1.5 years of follow-up

Alkali-Metal-Mediated Reversible Chemical Hydrogen Storage Using Seawater

The economic viability and systemic sustainability of a green hydrogen economy are primarily dependent on its storage. However, none of the current hydrogen storage methods meet all the targets set by the US Department of Energy (DoE) for mobile hydrogen storage. One of the most promising routes is through the chemical reaction of alkali metals with water; however, this method has not received much attention owing to its irreversible nature. Herein, we present a reconditioned seawater battery-assisted hydrogen storage system that can provide a solution to the irreversible nature of alkali-metal-based hydrogen storage. We show that this system can also be applied to relatively lighter alkali metals such as lithium as well as sodium, which increases the possibility of fulfilling the DoE target. Furthermore, we found that small (1.75 cm2) and scaled-up (70 cm2) systems showed high Faradaic efficiencies of over 94%, even in the presence of oxygen, which enhances their viability

Anesthetic consideration for patients with severe tracheal obstruction caused by thyroid cancer -A report of 2 cases-

To achieve safe airway management, it is essential first to predict whether there will be difficulties in intubating or ventilating the patient's airway. An enlarged thyroid mass can produce a tracheal obstruction by compression or intraluminal invasion or both. We report two patients with thyroid cancer that obstructed the trachea by compression or invasion. There was no difficulty in endotracheal intubation of the patients with marked thyroid enlargement or in securing passage of the endotracheal tube through the compressed or narrowed portion of the trachea

Toward a Lithium−“Air” Battery: The Effect of CO_2 on the Chemistry of a Lithium−Oxygen Cell

Lithium–oxygen chemistry offers the highest energy density for a rechargeable system as a “lithium–air battery”. Most studies of lithium–air batteries have focused on demonstrating battery operations in pure oxygen conditions; such a battery should technically be described as a “lithium–dioxygen battery”. Consequently, the next step for the lithium–“air” battery is to understand how the reaction chemistry is affected by the constituents of ambient air. Among the components of air, CO_2 is of particular interest because of its high solubility in organic solvents and it can react actively with O_2–•, which is the key intermediate species in Li–O_2 battery reactions. In this work, we investigated the reaction mechanisms in the Li–O_2/CO_2 cell under various electrolyte conditions using quantum mechanical simulations combined with experimental verification. Our most important finding is that the subtle balance among various reaction pathways influencing the potential energy surfaces can be modified by the electrolyte solvation effect. Thus, a low dielectric electrolyte tends to primarily form Li_2O_2, while a high dielectric electrolyte is effective in electrochemically activating CO_2, yielding only Li_2CO_3. Most surprisingly, we further discovered that a high dielectric medium such as DMSO can result in the reversible reaction of Li_2CO_3 over multiple cycles. We believe that the current mechanistic understanding of the chemistry of CO_2 in a Li–air cell and the interplay of CO_2 with electrolyte solvation will provide an important guideline for developing Li–air batteries. Furthermore, the possibility for a rechargeable Li–O_2/CO_2 battery based on Li_2CO_3 may have merits in enhancing cyclability by minimizing side reactions

Unexpected discovery of low-cost maricite NaFePO_4 as a high-performance electrode for Na-ion batteries

Battery chemistry based on earth-abundant elements has great potential for the development of cost-effective, large-scale energy storage systems. Herein, we report, for the first time, that maricite NaFePO_4 can function as an excellent cathode material for Na ion batteries, an unexpected result since it has been regarded as an electrochemically inactive electrode for rechargeable batteries. Our investigation of the Na re-(de)intercalation mechanism reveals that all Na ions can be deintercalated from the nano-sized maricite NaFePO_4 with simultaneous transformation into amorphous FePO_4. Our quantum mechanics calculations show that the underlying reason for the remarkable electrochemical activity of NaFePO_4 is the significantly enhanced Na mobility in the transformed phase, which is ~ one fourth of the hopping activation barrier. Maricite NaFePO_4, fully sodiated amorphous FePO_4, delivered a capacity of 142 mA h g^(−1) (92% of the theoretical value) at the first cycle, and showed outstanding cyclability with a negligible capacity fade after 200 cycles (95% retention of the initial cycle)

Transition metal-doped Ni-rich layered cathode materials for durable Li-ion batteries

Doping is a well-known strategy to enhance the electrochemical energy storage performance of layered cathode materials. Many studies on various dopants have been reported; however, a general relationship between the dopants and their effect on the stability of the positive electrode upon prolonged cell cycling has yet to be established. Here, we explore the impact of the oxidation states of various dopants (i.e., Mg2+, Al3+, Ti4+, Ta5+, and Mo6+) on the electrochemical, morphological, and structural properties of a Ni-rich cathode material (i.e., Li[Ni0.91Co0.09]O2). Galvanostatic cycling measurements in pouch-type Li-ion full cells show that cathodes featuring dopants with high oxidation states significantly outperform their undoped counterparts and the dopants with low oxidation states. In particular, Li-ion pouch cells with Ta5+- and Mo6+-doped Li[Ni0.91Co0.09]O2 cathodes retain about 81.5% of their initial specific capacity after 3000 cycles at 200???mA???g???1. Furthermore, physicochemical measurements and analyses suggest substantial differences in the grain geometries and crystal lattice structures of the various cathode materials, which contribute to their widely different battery performances and correlate with the oxidation states of their dopants