Structural Effect on Electrochemical Performance of 4,4’-Biphenyldicarboxylate Sodium Salts as an Anode for Na-ion Batteries

Battery Science and TechnologyThe crystal structures and electrochemical performance of 4,4’-biphenyldicarboxylate sodium salts is first introduced as an anode for Na-ion batteries. The structural modification of 4,4’-biphenyldicarboxylate sodium salts showing different degree of deprotonation and the coordination of a water molecule are deliberately accomplished through various precipitation and solvothermal methods, resulting in the formation of three different crystal structures even though they are composed of the same organic (bpdc) and inorganic (Na+) building blocks. The crystal structures are determined by single-crystal X-ray diffraction. The powder X-ray diffraction patterns showed the good agreement with the corresponding simulated patterns, indicating that the phase pure powders have the same crystal structure as the single crystals. The level of deprotonation in 4,4’-biphenyldicarboxylate sodium salts affects not only electrochemical performance but also reaction mechanisms. The fully deprotonated 4,4’-biphenyldicarboxylate disodium salt (Na2bpdc) exhibits promising electrochemical performance including reversible capacity of 220 mA h g-1 at ca. 0.5 V vs. Na/Na+, negligible capacity fading over 150 cycles, and excellent rate performance delivering about 100 mA h g-1 even at a 20C rate, which is better than monosodium 4,4’-biphenyldicarboxylate (NaHbpdc) that is partially deprotonated. This better rate performance of Na2bpdc salts is definitely attributed to the smaller particle size (short diffusion length) of that compared to NaHbpdc. However, even the dehydrated disodium 4,4’-biphenyldicarboxylate monohydrate (h-Na2bpdc) having similar size to NaHbpdc exhibited better rate performance than NaHbpdc. This means that the rate performance is affected by the degree of deprotonation in 4,4’-biphenyldicarboxylate sodium salts. Carboxylic group causes the large amount of electrolyte decomposition to form thick solid electrolyte interphase (SEI) layers, resulting in the increase of polarization due to large charge-transfer resistance. Also, the de/sodiaiton of Na2bpdc salts proceeds in a two-phase reaction, regardless of the degree of deprotonation. And, the amorphization of Na2bpdc salts occurred during cycling, even though the crystal structure is maintained. However, unlike the fully deprotonated showing reversible phase transition during sodiation and desodiation, the partially deprotonated exhibits irreversible phase transition during cyclings. It seems to be occurred the partially phase transition to Na2bpdc which is fully deprotonated due to the ion-exchange between Na+ and H+.ope

In situ electrochemical surface modification for high-voltage LiCoO2 in lithium ion batteries

High-voltage LiCoO2 has been revisited to improve the energy density of lithium ion batteries. LiCoO2 can deliver the reversible capacity of about 200 mA h g(-1) when the upper cut-off voltage increases to 4.55 V (vs. Li/Li+). However, the high upper cut-off voltage causes the severe failures of LiCoO2 such as structural degradation, electrolyte decomposition, and Co dissolution. Various surface-modified LiCoO2 materials have been introduced to suppress electrolyte decomposition and Co dissolution, thereby leading to the improved electrochemical performance. Most of the coated LiCoO2 materials are obtained through a conventional coating process such as sol-gel synthesis, which is complex and high-cost. In this paper, the in situ electrochemical coating method is introduced as a simple and low-cost coating process, where the electrolyte additive of Mg salts is electrochemically decomposed to form a MgF2-based coating layer on the LiCoO2 surface. LiCoO2 electrochemically coated with MgF2 suppresses Co dissolution in electrolytes, resulting in excellent electrochemical performance such as high reversible capacity of 198 mA h g(-1) and stable cycle performance over 100 cycles in the voltage range between 3 and 4.55 V (vs. Li/Li+) at 45 degrees C. The formation mechanism of MgF2 is also demonstrated through ex situ XPS and XANES analyses.

Intracellular Nanomaterial Delivery via Spiral Hydroporation

In recent nanobiotechnology developments, a wide variety of functional nanomaterials and engineered biomolecules have been created, and these have numerous applications in cell biology. For these nanomaterials to fulfill their promises completely, they must be able to reach their biological targets at the subcellular level and with a high level of specificity. Traditionally, either nanocarrier- or membrane disruption-based method has been used to deliver nanomaterials inside cells; however, these methods are suboptimal due to their toxicity, inconsistent delivery, and low throughput, and they are also labor intensive and time-consuming, highlighting the need for development of a next-generation, intracellular delivery system. This study reports on the development of an intracellular nanomaterial delivery platform, based on unexpected cell-deformation phenomena via spiral vortex and vortex breakdown exerted in the cross- and T-junctions at moderate Reynolds numbers. These vortex-induced cell deformation and sequential restoration processes open cell membranes transiently, allowing effective and robust intracellular delivery of nanomaterials in a single step without the aid of carriers or external apparatus. By using the platform described here (termed spiral hydroporator), we demonstrate the delivery of different nanomaterials, including gold nanoparticles (200 nm diameter), functional mesoporous silica nanoparticles (150 nm diameter), dextran (hydrodynamic diameters between 2–55 nm), and mRNA, into different cell types. We demonstrate here that the system is highly efficient (up to 96.5%) with high throughput (up to 1 × 106 cells/min) and rapid delivery (∼1 min) while maintaining high levels of cell viability (up to 94%)

Annular Leukocytoclastic Vasculitis in a Patient with Ulcerative Colitis

Leukocytoclastic vasculitis (LV) is characterized by neutrophilic invasion and fibrinoid necrosis along with endothelial enlargement in postcapillary venules. Annular appearance of LV (ALV) is rare, but it can be accompanied by several systemic diseases. One of these systemic diseases is ulcerative colitis (UC), a subgroup of inflammatory bowel disease. Only one case was previously reported in which ALV was associated with UC, and herein we present one more case. A 66-year-old woman presented with painful polycyclic erythema on both palms, which had been present for 4 days. She had suffered from UC for 5 years. The patient had no fever or other systemic symptoms, and histological examination demonstrated typical LV. 200 mg of oral dapsone was taken daily to rapidly reduce her symptoms and signs, and after 1 week all lesions resolved completely without any adverse events. ALV is not a distinct condition and it can appear in a broad range of small vessel vasculitides. Although ALV in patients with UC is a very rare combination, clinicians need to be aware of this possible association

Quantum dynamics as a physical resource

How useful is a quantum dynamical operation for quantum information processing? Motivated by this question we investigate several strength measures quantifying the resources intrinsic to a quantum operation. We develop a general theory of such strength measures, based on axiomatic considerations independent of state-based resources. The power of this theory is demonstrated with applications to quantum communication complexity, quantum computational complexity, and entanglement generation by unitary operations.Comment: 19 pages, shortened by 3 pages, mainly cosmetic change

Roles of GM-CSF in the Pathogenesis of Autoimmune Diseases: An Update.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was first described as a growth factor that induces the differentiation and proliferation of myeloid progenitors in the bone marrow. GM-CSF also has an important cytokine effect in chronic inflammatory diseases by stimulating the activation and migration of myeloid cells to inflammation sites, promoting survival of target cells and stimulating the renewal of effector granulocytes and macrophages. Because of these pro-cellular effects, an imbalance in GM-CSF production/signaling may lead to harmful inflammatory conditions. In this context, GM-CSF has a pathogenic role in autoimmune diseases that are dependent on cellular immune responses such as multiple sclerosis (MS) and rheumatoid arthritis (RA). Conversely, a protective role has also been described in other autoimmune diseases where humoral responses are detrimental such as myasthenia gravis (MG), Hashimoto\u27s thyroiditis (HT), inflammatory bowel disease (IBD), and systemic lupus erythematosus (SLE). In this review, we aimed for a comprehensive analysis of literature data on the multiple roles of GM-CSF in autoimmue diseases and possible therapeutic strategies that target GM-CSF production

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Vaccinia-Related Kinase 1 Is Required for the Maintenance of Undifferentiated Spermatogonia in Mouse Male Germ Cells

Vaccinia-related kinase 1 (VRK1) is a crucial protein kinase for mitotic regulation. VRK1 is known to play a role in germ cell development, and its deficiency results in sterility. Here we describe that VRK1 is essential for the maintenance of spermatogonial stem cells. To determine whether VRK1 plays a role in these cells, we assessed the population size of undifferentiated spermatogonia. Flow cytometry analyses showed that the number of undifferentiated spermatogonia was markedly reduced in VRK1-deficient testes. VRK1 was highly expressed in spermatogonial populations, and approximately 66% of undifferentiated spermatogonia that were sorted as an Ep-CAM+/c-kit−/alpha-6-integrin+ population showed a positive signal for VRK1. Undifferentiated stem cells expressing Plzf and Oct4 but not c-kit also expressed VRK1, suggesting that VRK1 is an intrinsic factor for the maintenance of spermatogonial stem cells. Microarray analyses of the global testicular transcriptome and quantitative RT-PCR of VRK1-deficient testes revealed significantly reduced expression levels of undifferentiated spermatogonial marker genes in early postnatal mice. Together, these results suggest that VRK1 is required for the proliferation and differentiation of undifferentiated spermatogonia, which are essential for spermatogenic cell maintenance