Hypoxia-induced miR-17-5p ameliorates the viability reduction of astrocytes via targeting p21

OBJECTIVE

Glial scars are widely seen as a mechanical barrier to central nervous system regeneration. Up to now, several studies have addressed and clarified how different lesion microenvironment properties affect astrogliosis. In particular, hypoxia induces the astrocyte astrogliosis, and thus promotes the formation of glial scars. However, little is known about the mechanism underlining such process. In the present study, we investigated the regulation by the miR-17-5p on the hypoxia-induced viability via targeting p21.

MATERIALS AND METHODS

We examined the expression of miR-15a, miR-16, miR-17-5p, hypoxia inducible factor-1α (HIF-1α) and p21 in the astrocytes under hypoxia, with quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) methods. Then investigated the regulatory role of miR-17-5p on the level of HIF-1α and p21, with qRT-PCR, WB and luciferase reporting assay, and examined the activity of astrocytes under normoxia or hypoxia.

RESULTS

Results demonstrated that miR-15a, miR-16, miR-17-5p were significantly upregulated, while HIF-1α and p21 were markedly downregulated in the hypoxia-treated astrocytes. And the transfection with miR-17-5p mimics significantly downregulated the expression of HIF-1α and p21 in such cells. And the luciferase reporter assay confirmed the targeting inhibiting of p21 by miR-17-5p in astrocytes. Moreover, the viability of astrocytes was significantly upregulated by the miR-17-5p mimics transfection under the hypoxia condition.

CONCLUSIONS

Our novel data suggest that the upregulated miR-17-5p contributes to the proliferation of astrocytes, in response to hypoxia, implying the potential role of miR-17-5p in the formation of glial scars.

Mesenchymal Stem Cell Modulates T Follicular Helper Cell to Induce Immunotolerance of Islet Allograft

OBJECTIVE

To verify whether mesenchymal stem cells protected the islet allograft via modulating follicular B helper T cells (Tfh) cells.

METHODS

The recipient mice were divided into 5 groups. Group A: the diabetic group (n = 12); Group B: islets alone group (n = 12); Group C: MSCs and islets co-transplanted group (n = 12, MSCs = 0.5 × 10(6)); Group D: MSCs and islets co-transplanted group (n = 12, MSCs = 1 × 10(6)); Group E: MSCs and islets co-transplanted group (n = 12, MSCs = 2 × 10(6)); One control group of normal NOD mice was set as well. ELISA was used to examine the autoantibody level of GAD65 Ab, insulin autoantibodies, and insulin. The Tfh count was determined by fluorescence-activated cell sorting. The insulin expression of islet grafts, the infiltration of lymphocytes, and the Tfh cells were observed via hematoxylin and eosin staining and immunohistochemical staining.

RESULTS

There was significant prolonged graft survival and more insulin expression of islet grafts observed in the co-transplant group. A lower level of the Tfh cells and autoantibody GAD65 Ab, insulin autoantibodies were also presented in the co-transplant group (P < .01). The infiltration of lymphocytes in the co-transplant group was notably less than in the islet-alone group (P < .01).

CONCLUSIONS

Mesenchymal stem cells were able to protect the islet allograft by regulating the follicular helper T cells.

Inactivation of Avian Influenza Viruses on Porous and Non-porous Surfaces is Enhanced by Elevating Absolute Humidity

This study was to evaluate the effect of absolute humidity (AH), a combined factor of temperature and relative humidity (RH), on inactivation of avian influenza viruses (AIVs) on surfaces. Suspensions of the H9N2 or H6N2 AIV were deposited onto carrier surfaces that were either porous (pine wood) or non-porous (stainless steel, synthetic rubber and glass). The inoculated carriers were incubated at 23, 35 or 45°C with 25% or 55% RH for up to 28 days. After incubation, virus was recovered and quantified by chicken embryo assays. The time required to obtain a log₁₀ reduction in virus infectivity (D-value) was estimated using a linear regression model. At AH of 5.2 g/m³ (23°C & 25% RH), both viruses survived up to 14 days on the porous surface and for at least 28 days on the non-porous surfaces. The corresponding D-values for H9N2 and H6N2 were 1.49 and 6.90 days on the porous surface and 7.81 and 12.5 days on the non-porous surfaces, respectively. In comparison, at AH of 9.9 g/m³ (35°C & 25% RH) or 11.3 g/m³ (23°C & 55% RH), the D-values for H9N2 and H6N2 dropped to ≤0.76 day on the porous surface and to ≤1.81 days on the non-porous surfaces. As the AH continued to rise from 11.3 to 36.0 g/m³ , the D-value for both viruses decreased further. The relationship between D-value and AH followed a form of y = ax^-b for both viruses. The D-values for H9N2 virus were significantly lower (P < 0.05) than those for H6N2 virus. Exposure to ammonia gas at concentrations of 86 and 173 ppm did not significantly alter test results. The findings give evidence that increasing the AH in poultry buildings following an outbreak of disease could greatly reduce the length of time required for their decontamination.

High frequency of OTOF mutations in Chinese infants with congenital auditory neuropathy spectrum disorder

Auditory neuropathy spectrum disorder (ANSD) is one of the most common diseases leading to hearing and speech communication barriers in infants and young children. The OTOF gene is the first gene identified for autosomal recessive non-syndromic ANSD, and patients with OTOF mutations have shown marked improvement of auditory functions from the cochlear implantation, but the true involvement of OTOF mutations in Chinese ANSD patients is still unknown which precludes the effective management of this disease. Here, we investigated the contribution of OTOF mutations to congenital ANSD patients in China. In all, 37 infants and young Children with ANSD were screened for all the exons of OTOF gene, of them 34 patients had no neonatal risk factors who were considered as congenital ANSD. The clinical manifestation and audiometric features were also investigated and compared in patients with and without OTOF mutations. In all, 14 of these subjects were shown to carry two or three mutant alleles of OTOF with the high frequency of 41.2% in congenital ANSD patients. In total, 15 novel pathogenic mutations and 10 reported mutations were identified. Our results confirmed that mutations in OTOF gene were a major cause of congenital ANSD in China. Identification of OTOF mutations can facilitate diagnosis, clinical intervention and counseling for congenital ANSD.

Abstract B12: The ALK inhibitor PF-06463922 shows significant response as a single agent in ALK/MYCN driven models of neuroblastoma

ALK inhibitors such as the ALK/MET/ROS1 inhibitor crizotinib (Xalkori) have shown clinical efficacy in a number of tumour types. However, in ALK positive neuroblastoma treatment with the ALK inhibitor crizotinib has proved more difficult, highlighting the exploration of new drugs as a clinical priority. A recent report of an increased percentage of ALK positive cases in the relapsed neuroblastoma patient population, together with the increased repertoire of ALK inhibitors now available, led to the investigation of alternative ALK inhibitors with potential for use in treatment of neuroblastoma. Here we report an investigation of the activity of a next generation ALK inhibitor in a range of in vitro and pre-clinical ALK driven neuroblastoma models.

Initially PF-06463922 was tested in various neuroblastoma cell lines and a range of gain-of-function ALK neuroblastoma mutations were subsequently analyzed in more detail in engineered Ba/F3 and PC12 cell models and by in vitro kinase assays, comparing the effect of PF-06463922 in abrogating cell growth and induced pharmacodynamics markers of response with the ALK inhibitor crizotinib. These results clearly show PF-06463922 to be a superior inhibitor of ALK kinase activity inhibiting all neuroblastoma mutant ALK forms assayed. Finally, single agent oral administration of PF-06463922 lead to induction of apoptosis and a dramatic reduction in tumour volume in a genetically engineered mouse model of treatment-resistant high-risk neuroblastoma driven by aberrant expression of MYCN and activated ALK. Taken together, our results suggest that PF-06463922 represents an important potential step forward in the treatment of relapsed neuroblastoma with mutated ALK.

Statement of significance: Our results together with PK/PD analysis of PF-06463922 suggest future clinical trial investigation of ALK positive neuroblastoma

Citation Format: J. Guan, L. Danielson, D. Chand, Y. Jamin, K. Ruuth, E. Tucker, G. Umapathy, A. El Wakil, B. Witek, T. W. Johnson, T. Smeal, L. Chesler, R. H. Palmer, B. Hallberg. The ALK inhibitor PF-06463922 shows significant response as a single agent in ALK/MYCN driven models of neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B12.

Reduction of autophagy markers mediated protective effects of JNK inhibitor and bucladesine on memory deficit induced by Aβ in rats

Autophagy, the process of self-degradation of cellular components, has an important role in neurodegenerative diseases, such as Alzheimer's disease. In this study, we investigated the effects of SP600125 as c-Jun N-terminal kinase (JNK) inhibitor and bucladesine as a cyclic adenosine 3',5'-monophosphate (cAMP) analog on spatial memory and expression of autophagic factors in Aβ-injected rats. Male Wistar rats were used. Rats were randomly allocated into five groups as following: amyloid beta (Aβ)-only group, Aβ + SP600125 (30 μg/1 μ/side, n = 7) and/or bucladesine (100 μM/1 μl/side, n = 7), and the normal control (vehicle only) group. The treatments were administered bilaterally to the CA1 sub-region of the hippocampus stereotaxically. Spatial reference memory was performed using Morris Water Maze 21 days later. The expression of authophagy markers (beclin1, Atg7, Atg12, and LC3 II/LC3 I) in the hippocampus was evaluated using western blotting. Compared to the vehicle group, Aβ administration reduced spatial reference learning (P < 0.001) and memory (P < 0.01) and upregulated the expression of beclin1, Atg7, Atg12, and LC3 II/I (P < 0.0001). Compare to Aβ-only group, the administration of SP600125 and/or bucladesine improved spatial reference learning (P < 0.001) and memory (P < 0.01). Compared to the Aβ-only group, the treatment with SP600125 and/or bucladesine also reduced beclin1, Atg7, Atg12, and LC3 II/I (P < 0.0001) which was similar to amount of normal rats. In summary, it seems that the improvement of spatial memory by SP600125 and/or bucladesine in Aβ-injected rats is in relation with normalizing of autophagy to the physiologic level, possibly through neuroprotection and/or neuroplasticity.

Abstract P6-05-12: Prognosis of subtypes of the mucinous breast carcinoma in Chinese women: A population-based study of 32-year experience (1983-2014)

Background: The heterogeneous nature of the mucinous breast cancer (MBC), with its subtypes of pure (PMBC) and mixed carcinoma (MMBC), calls for more precise individualized prognosis assessment. PMBC showed favorable prognosis in both Chinese and Caucasian women, with nodal status and TNM stage as the prognostic predictors [PMID: 18026874, 22451233]. However, few studies had investigated tumor biology and prognosis of MMBC in Chinese population, especially with respect to the different co-existing cancer components.

Methods: From January 1983 to December 2014, 197 consecutive MBC patients, including 117 PMBC and 80 MMBC, received breast cancer surgery in Peking Union Medical College Hospital. The clinicopathological characteristics, treatment choice, disease-free survival (DFS) and overall survival (OS) were compared both between PMBC vs MMBC, and among subgroups of MMBC according to the mixed entities, including 24 women with ductal caricinoma in situ (DCIS) and 45 with IDC. Univariate and Cox multivariate analyses were performed to identify the prognostic factors.

Results: The 197 MBC comprised 1.9% of contemporary 10,192 breast cancer (BC). Compared to PMBC, MMBC had significantly more lymph node metastasis (p=0.038), Her2 positivity (p=0.036), high Ki-67 index (defined as &gt;20%, p=0.026) and anti-Her2 targeted therapy (p=0.006). All these differences remained significant when the comparison were performed among PMBC, MBC+DCIS and MBC+IDC, and additional significant difference were identified in tumor size (p=0.036), pTNM stage (p=0.003) and chemotherapy (p=0.003). However, no significant difference was found in DFS or OS between any two subtypes/subgroups of MBC, including PMBC, MMBC, MBC+DCIS and MBC+IDC.

Table 1. Comparison of survival outcomes among PMBC, MBC+DCIS and MBC+IDC§SurvivalPMBC (N=117, Median, range, and Mean±SD)MBC+DCIS (N=24, Median, range, and Mean±SD)MBC+IDC (N=45, Median, range, and Mean±SD)P-ValueDFS (months)43 (1-233), 52.7±45.227 (1-84), 34.3±25.326 (1-113), 33.1±26.60.187OS (months)46 (1-312), 56.9±51.827 (1-84), 34.4±25.326 (1-113), 34.8±28.70.628§ Kaplan-Meier survival curves would be displayed in the poster

High Ki-67 index (p=0.046) appeared to be the significant DFS related prognostic factor for PMBC, whereas estrogen receptor (ER) status (univariate p=0.000, multivariate p=0.062) and immunophenotype (luminal, her2, or triple-negative, univariate p=0.000, multivariate p=0.079) might be the potential DFS predictors for MMBC. None of the above-mentioned clinicopathological factors could serve as OS predictors for MBC.

Conclusion: This population-based study showed that there were significant difference in nodal status, Ki-67, Her2 positivity and targeted therapy between PMBC and MMBC, and furthermore in tumor size, stage and chemotherapy among PMBC and subgroups of MMBC such as MBC+DCIS and MBC+IDC. However, survival outcomes were similar between these clinical entities and subgroups, suggesting the intra-tumoral heterogeneity might not interfere with survival outcomes of MBC in Chinese woman. High Ki-67 index was identified as the significant DFS related prognostic factor for PMBC, whereas ER status and immunophenotype as the potential DFS predictors for MMBC.

Citation Format: Yao R, Pan B, Sun Q, Zhou Y, Mao F, Lin Y, Guan J, Wang X, Zhang Y, Zhang X, Shen S, Zhong Y, Xu Y, Shi J, Zhu Q, Cai F, Liang Z. Prognosis of subtypes of the mucinous breast carcinoma in Chinese women: A population-based study of 32-year experience (1983-2014). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-05-12.

The Nature of the Interlayer Interaction in Bulk and Few-Layer Phosphorus

Sensitive dependence of the electronic structure on the number of layers in few-layer phosphorene raises a question about the true nature of the interlayer interaction in so-called "van der Waals (vdW) solids". We performed quantum Monte Carlo calculations and found that the interlayer interaction in bulk black phosphorus and related few-layer phosphorene is associated with a significant charge redistribution that is incompatible with purely dispersive forces and not captured by density functional theory calculations with different vdW corrected functionals. These findings confirm the necessity of more sophisticated treatment of nonlocal electron correlation in total energy calculations.

A pilot study of conformal radiotherapy combined with erlotinib-based multimodality therapy in newly diagnosed metastatic non-small-cell lung cancer

OBJECTIVE

Lung cancer is the leading cause of cancer-related death in the world, particularly in major cities in China. We aimed to determine the benefit of survival and toxicity of Conformal Radiotherapy (CRT) combined with erlotinib-based multimodality therapy in newly diagnosed metastatic non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Newly diagnosed metastatic NSCLC patients were treated with CRT and erlotinib, with or without chemotherapy matched protocol. The patients received CRT with a dose of 30-66 Gy. Erlotinib was used at least one 28-day cycle. The primary end point was overall survival (OS).

RESULTS

Thirty-two patients were analyzed. The median OS was 517 days. Patients with only one metastasis showed longer survival than patients with multi-metastases (986 vs. 380 days, n = 8 vs. 24, p = .009). Patients with multiple metastases in brain conferred worse survival for patients without and with sole brain metastasis (321 vs. 700 days, n=11 vs 21, p = .006). There was no significant difference in median survival whether erlotinib was used as a first-, second- or third-line therapy (380 vs. 700 vs. 310 days, n = 10 vs. 15 vs 7, respectively. p = .179). Patients with TTCRT > 90 days had longer OS than patients with TTCRT ≤ 90 days (749 vs. 322 days, n = 11 vs. 21, p = .012). Patients tolerated treatment with limited Grade 1/2 toxicity.

CONCLUSIONS

In this study, patients with newly diagnosed metastatic NSCLC had survival benefits when erlotinib was used combined with CRT. Further prospective trials are needed to derive maximal benefit from the drug treatment.

Detection of a superconducting phase in a two-atom layer of hexagonal Ga film grown on semiconducting GaN(0001)

The recent observation of the superconducting state at atomic scale has motivated the pursuit of exotic condensed phases in two-dimensional (2D) systems. Here we report on a superconducting phase in two-monolayer crystalline Ga films epitaxially grown on wide-band-gap semiconductor GaN(0001). This phase exhibits a hexagonal structure and only 0.552 nm in thickness, nevertheless, brings about a superconducting transition temperature Tc as high as 5.4 K, confirmed by in situ scanning tunneling spectroscopy and ex situ electrical magnetotransport and magnetization measurements. The anisotropy of critical magnetic field and Berezinski-Kosterlitz-Thouless-like transition are observed, typical for the 2D superconductivity. Our results demonstrate a novel platform for exploring atomic-scale 2D superconductors, with great potential for understanding the interface superconductivity.

17-AAG enhances the cytotoxicity of flavopiridol in mantle cell lymphoma via autophagy suppression

Flavopiridol, a cyclin-dependent kinase inhibitor (CDKI), shows promising anti-tumor activity in hematologic malignancies. However, Flavopiridol-induced protective autophagy may lead to drug resistance. Here we found that Hsp90 inhibitor 17-AAG can sensitize mantle cell lymphoma (MCL) cells to flavopiridol by suppressing flavopiridol-triggered protective autophagy. The suppressing effect of 17-AAG on autophgy was mediated by Beclin1 degradation and ERK inactivation. Furthermore, 17-AAG enhanced flavopiridol-induced apoptosis and growth suppression in MCL cells. Our study may provide some insights into CDKI -targeted chemotherapies.

C-reactive protein and risk of fracture: a systematic review and dose-response meta-analysis of prospective cohort studies

This study systematically reviews prospective cohort studies evaluating the relationship between C-reactive protein (CRP) concentrations and subsequent fracture risk. The positive association cannot completely explain the existing evidence, and further studies are needed to demonstrate the shape of the association.

INTRODUCTION

We aimed to perform a systematic review and dose-response meta-analysis of published prospective studies evaluating associations of high-sensitivity CRP (hs-CRP) levels with fracture risk in general populations.

METHODS

We identified relevant studies by searching MEDLINE and EMBASE databases from their inception to May 20, 2014. We included published prospective studies evaluating the associations of hs-CRP levels with risk of fracture in general populations. Two reviewers working independently abstracted the data.

RESULTS

Eight prospective cohort studies involving 34,840 participants and 3,407 incident fracture events were eligible for the present analyses. A meta-analysis of six prospective studies showed that the overall risk for incident fracture in a comparison of individuals in the top tertile with those in the bottom tertile of baseline hs-CRP levels was 2.14 [95% confidence interval (CI) 1.51-3.05, I(2) = 62.3%]. The moderate heterogeneous disappeared when one study was excluded. However, the remaining two studies reported inconsistent results. One study with the biggest sample size showed a U-shaped association for CRP and fracture risk (the association was positive when CRP > 1 mg/L). Similarly, another study reported that per doubling of CRP was positive only when CRP > 3 mg/L.

CONCLUSION

In summary, the present analysis showed that the relationship between CRP concentrations and subsequent fracture risk is still inconsistent. The positive association cannot completely explain the existing evidence, and further larger prospective cohorts with more power are needed to demonstrate the shape of the association, especially for the relatively low CRP concentrations, such as less than 3 mg/L.

Evaluation of a 2-channel portable device and a predictive model to screen for obstructive sleep apnea in a laboratory environment

BACKGROUND

Various portable monitors for identifying obstructive sleep apnea (OSA) have been investigated and reported to enable accurate recording of OSA severity. However, more information is needed from different populations. This study was conducted to evaluate the efficiency of a portable 2-channel sleep apnea device (SleepView) for screening OSA in the Chinese population.

METHODS

Ninety-three consecutive subjects underwent simultaneous SleepView testing and laboratory polysomnography (PSG) monitoring. Data were collected and blindly analyzed. The efficiency of the SleepView device and a newly established predictive model for identifying OSA was evaluated in comparison with PSG.

RESULTS

Good agreement was evident between the SleepView and PSG based on the apnea-hypopnea index (AHI; r(2) = 0.84, P < .01). The median AHI yielded by the SleepView was higher than that of PSG: 33.2 (interquartile range of 10.5-53.3) versus 19.2 (interquartile range of 5.2-53.6). The sensitivity and specificity of the SleepView for a PSG AHI of ≥ 5 were 80.28% and 95.45%, respectively, and the cutoff was 16.8. The area under the receiver operating curve for PSG AHIs of ≥ 5, > 15, and > 30 was 0.923, 0.924, and 0.979, respectively. When the AHI and oxygen desaturation index calculated by the SleepView were combined with waist circumference, the new predictive model showed a higher sensitivity of 92.96% and a specificity of 95.45% for a PSG AHI of ≥ 5, and the corresponding area under the receiver operating curve was 0.983.

CONCLUSIONS

The SleepView device exhibited acceptable diagnostic accuracy for OSA in the Chinese population, especially in the severe OSA group. A practical predictive model comprising waist circumference, AHI, and oxygen desaturation index obtained with the SleepView was highly effective for screening even mild OSA. This simple and practical device may serve as a useful tool to screen for OSA. Further studies are required to validate the diagnostic efficiency of the SleepView in the home environment and in different populations.

Effects of beraprost sodium on renal function and inflammatory factors of rats with diabetic nephropathy

Beraprost sodium (BPS) is a prostaglandin analogue. We investigated its effects on rats with diabetic nephropathy. There were 20 rats each in the normal control group (NC), the diabetic nephropathy group (DN), and the BPS treatment group. The rats in DN and BPS groups were given a high-fat diet combined with low-dose streptozotocin intraperitoneal injections. The rats in the BPS group were given daily 0.6 mg/kg intraperitoneal injections of this drug. After 8 weeks, blood glucose, 24-h UAlb, Cr, BUN, hs-CRP, and IL-6 levels increased significantly in the DN group compared with the NC group; however, the body mass was significantly reduced in the DN group compared with the NC group. Blood glucose, urine output, 24-h UAlb, Cr, hs-CRP, and IL-6 levels were significantly lower in the BPS group than in the DN group; the body mass was significantly greater in the DN group. Therefore, we concluded that BPS can improve renal function and protect the kidneys of DN rats by reducing oxidative stress and generation of inflammatory cytokines; it also decreases urinary protein excretion of rats with diabetic nephropathy.

Fas/FasL in the immune pathogenesis of severe aplastic anemia

Fas/FasL protein expression of bone marrow hematopoietic cells was investigated in severe aplastic anemia (SAA) patients. Fas expression was evaluated in CD34(+), GlycoA(+), CD33(+), and CD14(+) cells labeled with monoclonal antibodies in newly diagnosed and remission SAA patients along with normal controls. FasL expression was evaluated in CD8(+) cells in the same manner. In CD34(+) cells, Fas expression was significantly higher in the newly diagnosed SAA group (46.59 ± 27.60%) than the remission (6.12 ± 3.35%; P < 0.01) and control (8.89 ± 7.28%; P < 0.01) groups. In CD14(+), CD33(+), and GlycoA(+) cells, Fas levels were significantly lower in the newly diagnosed SAA group (29.29 ± 9.23, 46.88 ± 14.30, and 15.15 ± 9.26%, respectively) than in the remission (47.23 ± 31.56, 67.22 ± 34.68, and 43.56 ± 26.85%, respectively; P < 0.05) and normal control (51.25 ± 38.36, 72.06 ± 39.88, 50.38 ± 39.88%, respectively; P < 0.05) groups. FasL expression of CD8(+) cells was significantly higher in the newly diagnosed SAA group (89.53 ± 45.68%) than the remission (56.39 ± 27.94%; P < 0.01) and control (48.63 ± 27.38%; P <0.01) groups. No significant differences were observed between the remission and control groups. FasL expression in CD8(+) T cells was significantly higher in newly diagnosed patients, and CD34(+), CD33(+), CD14(+), and GlycoA(+) cells all showed Fas antigen expression. The Fas/FasL pathway might play an important role in excessive hematopoietic cell apoptosis in SAA bone marrow. Furthermore, CD34(+) cells are likely the main targets of SAA immune injury.

Comparison of tetragonal and cubic tin as anode for Mg ion batteries

Using first-principles calculation based on density functional theory, diffusion of Mg atom into α- and β-Sn was investigated. The diffusion barriers are 0.395 and 0.435 eV for an isolated Mg atom in the α- and β-Sn, respectively. However, the diffusion barriers of the Mg atom decrease in the α-Sn, whereas they increase in the β-Sn, when an additional Mg atom was inserted near the original diffusing Mg atom, which is mainly due to strong binding of Mg-Mg atoms in the β-Sn. Therefore, it is better to use the α-Sn, rather than the β-Sn, as an anode material for Mg ion batteries.