RESUMO
The migration of mobile ionic halide vacancies is usually considered detrimental to the performance and stability of perovskite optoelectronic devices. Taking advantage of this intrinsic feature, we fabricated a CsPbI3 perovskite quantum dot (PQD)-based write-once-read-many-times (WORM) memory device with a simple sandwich structure that demonstrates intrinsic ternary states with a high ON/OFF ratio of 103:102:1 and a long retention time of 104 s. Through electrochemical impedance spectroscopy, we proved that the resistive switching is achieved by the migration of mobile iodine vacancies (VIs) under an electric field to form conductive filaments (CFs). Using in situ conductive atomic force microscopy, we further revealed that the multilevel property arises from the different activation energies for VIs to migrate at grain boundaries and grain interiors, resulting in two distinct pathways for CFs to grow. Our work highlights the potential of CsPbI3 PQD-based WORM devices, showcasing intrinsic multilevel properties achieved in a simple device structure by rationally controlling the drift of ionic defects.
RESUMO
In this work IR spectral characteristics of PîO groups are used to evaluate the strength of OHO hydrogen bonds. Three phosphine oxides: triphenylphosphine oxide, tributylphosphine oxide and hexamethylphosphoramide are investigated as proton acceptors. The results of the experimental IR study and DFT calculation of 30 complexes formed by phosphine oxides with various substituted phenols or CF3CH2OH in CCl4 solution at room temperature are reported. We show that the PîO vibrational frequency changes non-linearly upon hydrogen bond formation and strengthening and that the shift of the PîO band could be used for the estimation of hydrogen bond strength in complexes with phosphine oxides. The accuracy of these estimations and the influence of solvation effects on the main characteristics of complexes are discussed.
RESUMO
The bulk morphology of the active layer of organic solar cells (OSCs) is known to be crucial to the device performance. The thin film device structure breaks the symmetry into the in-plane direction and out-of-plane direction with respect to the substrate, leading to an intrinsic anisotropy in the bulk morphology. However, the characterization of out-of-plane nanomorphology within the active layer remains a grand challenge. Here, we utilized an X-ray scattering technique, Grazing-incident Transmission Small-angle X-ray Scattering (GTSAXS), to uncover this new morphology dimension. This technique was implemented on the model systems based on fullerene derivative (P3HT:PC71BM) and non-fullerene systems (PBDBT:ITIC, PM6:Y6), which demonstrated the successful extraction of the quantitative out-of-plane acceptor domain size of OSC systems. The detected in-plane and out-of-plane domain sizes show strong correlations with the device performance, particularly in terms of exciton dissociation and charge transfer. With the help of GTSAXS, one could obtain a more fundamental perception about the three-dimensional nanomorphology and new angles for morphology control strategies towards highly efficient photovoltaic devices.
RESUMO
OBJECTIVE: Intramural pregnancy (IMP) is a rare type of ectopic pregnancy and potentially fatal. Early diagnosis and management of IMP are important to preserve patient fertility. Here, we describe the use of minimally-invasive surgery for early IMP. STUDY DESIGN: We retrospectively analyzed the clinical data of eight patients with IMP treated at our center (January 2010 to December 2018) and reviewed the literature describing minimally-invasive treatment of IMP. RESULTS: All eight patients had at least one risk factor for IMP. Two cases were confirmed by ultrasound, but ectopic pregnancy or gestational trophoblastic disease were initially suspected in the other cases. Surgery (laparoscopic in three patients, hysteroscopic in one patient, and laparoscopic combined with hysteroscopic in four patients) was successful in all cases, and all patients recovered well without complications. The literature review identified 14 articles describing 17 cases of IMP managed with minimally-invasive surgery. Laparoscopic surgery was used successfully as a sole treatment in 10 cases and after failure of hysteroscopic surgery in six cases. Only one case was treated with a combination of hysteroscopic surgery and methotrexate. Interestingly, one case at our center presented with a sinus connecting the gestational sac and uterine cavity and was treated successfully using hysteroscopic surgery during early pregnancy. CONCLUSIONS: Laparoscopic surgery is a feasible management option for most cases of early IMP. Hysteroscopic surgery may be appropriate for cases where a sinus connects the gestational sac with the uterine cavity or when cornual ectopic pregnancy needs to be excluded.
Assuntos
Laparoscopia , Gravidez Cornual , Gravidez Ectópica , Feminino , Humanos , Metotrexato/uso terapêutico , Gravidez , Gravidez Cornual/diagnóstico por imagem , Gravidez Cornual/cirurgia , Gravidez Ectópica/diagnóstico por imagem , Gravidez Ectópica/cirurgia , Estudos Retrospectivos , UltrassonografiaRESUMO
Synthesis and applications of one dimensional (1D) metal nanostructures have attracted much attention. However, one-step synthesis of bimetallic nanowires (NWs) has remained challenging. In this work, we developed a microorganism-mediated, hexadecyltrimethylammonium bromide (CTAB)-directed (MCD) approach to synthesize closely packed and long Au-Ag NWs with the assistance of a continuous injection pump. Characterization results confirmed that the branched Au-Ag alloy NWs was polycrystalline. And the Au-Ag NWs exhibited a strong absorbance at around 1950 nm in the near-infrared (NIR) region, which can find potential application in NIR absorption. In addition, the Au-Ag NWs showed excellent surface-enhanced Raman scattering (SERS) enhancement when 4-mercaptobenzoic acid (MBA) and rhodamine 6G (R6G) were used as probe molecules.
RESUMO
The associations between methylenetetrahydrofolate reductase (MTHFR) polymorphism and methotrexate (MTX)-induced toxicities in patients with acute lymphoblastic leukemia (ALL) have been evaluated in various populations, with the results remained conflicting. Therefore, we conducted a meta-analysis by combining available data to derive a more precise estimation of the association. PubMed, Embase, and China National Knowledge Infrastructure were searched until 21 September 2011 to identify eligible studies. A total of 14 studies were included, with all studies investigating MTHFR C677T polymorphism while nine of them investigating MTHFR A1298C polymorphism only. Results suggested that MTHFR C677T polymorphism was associated with significantly increased risk of MTX-induced toxicity, specifically liver toxicity (TT/CT vs. CC: odds ratio (OR) = 1.70, 95 % confidence interval (CI) = 1.05-2.75), myelosuppression (TT vs. CT/CC: OR = 2.82, 95 %CI = 1.25-6.34), oral mucositis (TT/CT vs. CC: OR = 3.68, 95 %CI = 1.73-7.85), gastrointestinal toxicity (TT/CT vs. CC: OR = 2.36, 95 %CI = 1.36-4.11), and skin toxicity (T vs. C: OR = 2.26, 95 %CI = 1.07-4.74). MTHFR A1298C polymorphism was found to be associated with decreased risk of skin toxicity (CC/AC vs. AA: OR = 0.11, 95 %CI = 0.01-0.85). Genotyping of MTHFR polymorphism, C677T particularly, prior to treatment for ALL is likely to be useful with the aim of tailoring MTX therapy and thus reducing the MTX-related toxicities. However, further studies with larger data set and well-designed models are required to validate our findings.
Assuntos
Antimetabólitos Antineoplásicos/efeitos adversos , Metotrexato/efeitos adversos , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo de Nucleotídeo Único , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Alelos , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/uso terapêutico , Genótipo , Humanos , Metotrexato/administração & dosagem , Metotrexato/uso terapêuticoRESUMO
BACKGROUND: Results from published studies on the association of donor or recipient IL-6 -174G/C (rs1800795) polymorphism with acute rejection (AR) of renal allograft are conflicting. We performed a meta-analysis to estimate the possible association. METHODS: Studies were identified by searching PUBMED and EMBASE until July 1, 2011. Meta-analysis was performed in a fixed/random effects model using Revman 5.0.25 and STATA10.0. RESULTS: Seven studies addressing the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute rejection of renal allograft were identified. Pooled OR based on 341 cases (whose recipient developed acute rejection) and 702 controls (whose recipient did not develop acute rejection) was 0.59 (95% CI, 0.26-1.33; p=0.20), with a strong between-study heterogeneity. No association was observed in the subgroup analysis based on ethnicity. 13 studies evaluating the association between recipient IL-6 -174G/C polymorphism and acute rejection were identified. Pooled OR based on 451 cases (patients did not develop acute rejection) and 848 controls was 1.00 (95% CI=0.72-1.37; p=0.98), with a weak between-study heterogeneity. CONCLUSIONS: Donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism had a tendency of decreased risk for acute rejection, although it was not statistically significant. Recipient high producer genotype was not associated with acute rejection of renal allograft. Additional well designed studies with larger sample size are needed to support our findings, especially for the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute renal allograft rejection.
Assuntos
Rejeição de Enxerto/genética , Interleucina-6/genética , Transplante de Rim/imunologia , Polimorfismo de Nucleotídeo Único , Doença Aguda , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transplante Homólogo/imunologiaRESUMO
BACKGROUND: Results from published studies on the association of donor or recipient TNF-A -308G/A polymorphism with acute rejection (AR) of renal allograft are inconsistent. We performed a meta-analysis to summarize the possible association. METHODS: Studies were identified by searching PUBMED, EMBASE and Chinese National Knowledge Infrastructure (CNKI) databases until March 22, 2011. Meta-analysis was performed in a fixed/random-effect model using Revman 5.0.25 and STATA10.0. RESULTS: Eight studies evaluating the association between donor TNF-A -308G/A polymorphism and acute rejection of renal allograft were identified. Pooled OR based on 460 cases (whose recipient developed AR) and 623 controls (whose recipient did not develop AR) was 1.44 (95% CI=1.05-1.99, p=0.03). No association was detected in the subgroup analysis based on ethnicity. 28 studies evaluating the association between recipient TNF-A -308G/A polymorphism and acute rejection were identified. Pooled OR based on 1411 cases (patients did not develop AR) and 2088 controls was 1.39 (95% CI=1.06-1.82, p=0.02). Two studies evaluating the association between recipient TNF-A -308G/A polymorphism and recurrent acute rejection were identified. Pooled OR based on 225 cases (patients with ≤1 AR) and 34 controls (patients with ≥2 AR) was 0.28 (95% CI=0.13-0.62, p=0.002). CONCLUSIONS: Our meta-analysis provided evidence that TNF2 allele positive genotype of donor or recipient was associated with increased risk of incidence of acute rejection of renal allograft. Recipient TNF2 allele positive genotype is also associated with increased risk of recurrence of acute rejection of renal allograft. However, additional studies with large sample size and better study designs are warranted to verify our finding.