Trifunctional Trichloroacetic Acid Incorporated Mixed-Halide Perovskites for Spectrally Stable Blue Light-Emitting Diodes

Metal halide perovskites have won great recognition in light-emitting diodes (LEDs). Nevertheless, the development of blue perovskite LEDs is facing a bottleneck in improving the device performance. Although mixed chloride/bromide perovskites can achieve pure-blue emission straightforwardly, higher chloride content will induce the challenges of low photoluminescence quantum yield and poor spectra stability resulting from the chloride vacancy defects and resultant halide ion migration under an electric field. In this work, we introduce a reliable trifunctional additive trichloroacetic acid into mixed-halide perovskites, which can provide additional chloride to fill halide vacancies, passivate the uncoordinated Pb²⁺ ion defects, and promote the crystallization effectively. Owning to the utilization of trichloroacetic acid, the ultimate pure-blue perovskite LED obtains stable electroluminescent spectra at 477 nm under various bias and demonstrates a 5-fold external quantum efficiency improvement (up to 6.6%).

Photopatternable and Highly Conductive PEDOT:PSS Electrodes for Flexible Perovskite Light-Emitting Diodes

Flexible perovskite light-emitting diodes (PeLEDs) constitute an emerging technology opening new opportunities in the fields of lighting and display for portable and wearable electronics. Poly(3,4-ethylenedioxythiophene):poly(stryrenesulfonate) (PEDOT:PSS) as one of the most promising flexible electrode materials has attracted extensive attention. However, the patterning and conductivity issues of PEDOT:PSS electrodes should be addressed primarily. Here, a photopolymerizable additive is proposed to endow the PEDOT:PSS electrodes with photopatternability. Moreover, this additive can also improve the conductivity of the PEDOT:PSS electrode from 0.16 to 627 S/cm because of the phase separation between PEDOT and PSS components and conformation transition of PEDOT chains. Eventually, highly conductive PEDOT:PSS electrodes with various patterns are applied in flexible PeLEDs, demonstrating a high luminance of 25972 cd/m² and a current efficiency of 25.1 cd/A. This work provides a facile and effective method of patterning and improving the conductivity of PEDOT:PSS electrodes simultaneously, demonstrating the great potential of PEDOT:PSS electrodes in flexible perovskite optoelectronics.

Multidentate Zwitterionic Ligand-Assisted Formation of Pure Bromide-Based Perovskite Nanosheets and Their Application in Blue Light-Emitting Diodes

Perovskite light-emitting diodes (PeLEDs) have demonstrated rapid development during the past decade, whereas the inferior device performance of blue ones impedes the application in full-color display and lighting. Low-dimensional perovskites turn out to be the most promising blue-emitters owing to their superior stability. In this work, a multidentate zwitterionic l-arginine is proposed to achieve blue emission from pure bromide-based perovskites by in situ-forming low-dimensional nanosheets. First, l-arginine can promote the formation of perovskite nanosheets due to the strong interaction between the peripheral guanidinium cations and [PbBr₆]^4- octahedral layers, enabling a significant blue-shift. Second, the carboxyl group within l-arginine can passivate uncoordinated Pb²⁺ ions, improving the device performance. Finally, a blue PeLED is successfully constructed on the basis of the l-arginine-modulated perovskite film, demonstrating a peak luminance of 2152 cd/m², an external quantum efficiency of 5.4%, and operation lifetime of 13.81 min. Further, the enlightenment from this work is hopefully to be applied in rationally designing spacer cations for low-dimensional perovskite optoelectronic devices.

Basic Amino Acids Modulated Neutral-pH PEDOT:PSS for Stable Blue Perovskite Light-Emitting Diodes

State-of-the-art external quantum efficiencies (EQEs) have exceeded 20% for near-infrared, red, and green perovskite light-emitting diodes (PeLEDs) so far. Nevertheless, the cutting-edge blue counterparts demonstrate an inferior device performance, which impedes the commercialization and industrialization of PeLEDs in ultrahigh-definition displays. As the most popular hole transport layer, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) bears the acidic and hygroscopic drawbacks, which deteriorates the device efficiency and long-term stability of blue PeLEDs. In this work, the basic amino acids with zwitterionic characteristics are proposed to modulate the pH of PEDOT:PSS, which are arginine, lysine, and histidine. It is found that they play a triple function to the blue perovskite films: modulating the acidity of PEDOT:PSS, controlling the crystalline process, and passivating the defects at the PEDOT:PSS/perovskite interface. As a result, the utilization of neutral PEDOT:PSS leads to a significant enhancement in stability and photoluminescence quantum yield. Eventually, the pure-blue PeLEDs achieve a record EQE of 5.6% with the emission peak at 467 nm. This research proves that the interfacial engineering of hole transport layers is a reliable strategy to enhance the device efficiency and operation stability of blue PeLEDs.

MELD and Child-Pugh Scores Are Related to Immune Status of Intrahepatic Natural Killer Cells in Liver Transplant Candidates

BACKGROUND

The role and phenotypic alterations of intrahepatic natural killer (NK) cells in liver disease were investigated. Although intrahepatic NK cells reportedly functionally deteriorate in the fibrotic liver, it remains unclear how the clinical severity of liver disease affects intrahepatic NK cells in patients with advanced liver failure.

METHODS

We analyzed the phenotypic properties of intrahepatic NK cells by using mononuclear cells extracted from ex vivo liver perfusate effluents from patients who underwent liver transplantation. The relationship between the clinical severity of liver disease and the phenotype of intrahepatic NK cells in these patients was also evaluated. To estimate the immunological responsiveness of intrahepatic NK cells, phenotypic enhancement after interleukin-2 stimulation was analyzed.

RESULTS

Intrahepatic NK cells from patients with advanced liver failure exhibited down-regulated monomodal expression of NKp46, a major activating molecule. Notably, the expression level of NKp46 decreased depending on the severity of liver disease, Model for End-Stage Liver Disease score, and Child-Pugh score rather than the etiology. After in vitro recombinant interleukin-2 stimulation, the enhancement of expression of cytotoxic molecules, NKp44, and tumor necrosis factor-related apoptosis-inducing ligand was significantly impaired in intrahepatic NK cells from patients with liver failure, concurrently with decreased expression of CD122 and interleukin-2 receptor beta.

CONCLUSIONS

Our results suggest that terminal deterioration of liver environments by chronic liver disease impairs the potential of local NK cells, depending on the severity of the deterioration. These influences of advanced liver failure on intrahepatic NK cells may be attributed to multicentric carcinogenesis in patients with liver failure.

HPV16 E6 mutations and p53 codon72 polymorphism among women with cervical intraepithelial neoplasia 2 and 3 in China

OBJECTIVE

To study the distribution of HPV16 E6 gene mutations and p53 codon72 polymorphism among women with HPV16+ cervical precancerous lesions and explore their relationship with the risk of cervical intraepithelial neoplasia (CIN) 2, 3. Materials and Meth- ods: This study analyzed a total of 112 cases of exfoliated HPV16+ cervical cell specimens which were divided into group I (normal and CIN1, 55 cases) and group2 (CIN2, 3, 57 cases). Among the 112 specimens, 85 cases were successfully amplified for HPV E6 gene by PCR and the PCR products were sequenced directly. P53 codon72 region was also amplified from the 112 specimens and the PCR products were sequenced directly and compared with the standard sequence.

RESULTS

Among the 85 amplified HPV sequences, point mutations such as T178G, T350G, G132A, A442C, T310G, G94T, C551A, etc. were found, among which, T178G showed the highest rate (51.76%). The rate of HPV16 E6 mutation T178G in CIN2, 3 group was significantly higher than that in normal and CINI group, i.e., in the 112 amplified p53 codon72 sequences, the distribution of Pro/Pro genotype in normal, and CIN1 group was significantly different from that in CIN2, 3 groups, and the disease risk of Pro/Pro genotype was much higher than that of Arg/Arg and Arg/Pro genotypes.

CONCLUSION

HPV16 E6 T178G mutation increases the disease risk of CIN2, 3. Meanwhile, compared with Arg/Arg and Arg/Pro genotypes, p53 codon72 Pro/Pro genotype more associated with the disease risk of CIN2, 3.

Childhood obesity and its health consequence in China

Analyses of data from the representative 2002 National Nutrition and Health Survey were used to assess the likelihood of metabolic complications of overweight and obesity in Chinese children aged 7-17 years. Chinese criteria for body mass index classification were used for overweight and obesity with the 75th percentile US adolescent values for waist circumferences and all the metabolic criteria for blood pressure, lipids, fasting glucose established for US adolescents. Diabetes in 7-12-year-olds was 0.2% and 0.4% in children aged 12-18 years. Prevalences of dyslipidaemia (61.9%), hypertriglyceridaemia (18.2%) and low high-density lipoprotein cholesterol (56.1%) were high and 16.0% of 15-18 years had hypertension. The overall prevalence of the metabolic syndrome was 3.3% with more than half the children having at least one metabolic abnormality and 19.8% having at least two. All the metabolic parameters were significantly elevated in the overweight and obese children except high-density lipoprotein cholesterol. These data emphasize the marked sensitivity of Chinese children to the metabolic complications of overweight and obesity and amplify the need for early preventive measures.

Prevalence of the metabolic syndrome in Chinese adolescents

Since national figures on the occurrence of metabolic syndrome among Chinese adolescents are lacking, this study aims to estimate its prevalence and distribution among Chinese youngsters. The 2002 China National Nutrition and Health Survey is a nationally representative cross-sectional study. Applying the criteria for US adolescents, we estimated the prevalence of metabolic syndrome among 2761 adolescents aged 15 to 19 years. The prevalence of metabolic syndrome among Chinese adolescents overall was 3.7 % (10 % in US adolescents). It was 35.2 %, 23.4 % and 2.3 % among adolescents who were overweight (BMI > or = 95th percentile), at risk of overweight (BMI between 85th and 95th percentile) and normal weight (BMI below the 85th percentile), respectively. Urban boys had the highest rate (5.8 %) compared with girls and rural youngsters. Among adolescents who had a BMI > or = 85th percentile and one or two parent(s) with metabolic syndrome, the prevalence was 46.4 %. A total of 96 % of overweight adolescents had at least one and 74.1 % overweight adolescents had at least two abnormalities of metabolic syndrome. Based on these figures, it is estimated that more than three million Chinese adolescents have metabolic syndrome. Both overweight and metabolic syndrome prevalence among adolescents are still relatively low in China, but the prevalence of metabolic syndrome among Chinese overweight adolescents is similar to those living in the USA.

[Indicators for the assessment of iodine nutritional status]

Selecting appropriate evaluation indicators for surveying and monitoring iodine nutritional status is needed. The indicators, which are used commonly in recent literature, are urinary iodine, thyroid volume, dietary iodine intake, thyroid function parameters and intelligence quotient. These indicators are summarized on their clinical significance, application range, expression method and so on. The purpose of this review is to provide some scientific references for people who are working on prevention and treatment of iodine deficiency disorders.

[Research on some enzyme activities in the assessment of zinc nutritional status of growing rats]

Male weaning rats were divided randomly into five groups. They were fed with diets containing zinc deficient(DZ), high zinc(HZ), normal zinc (NZ) and high zinc pair-fed with zinc deficient group(HZP) respectively. The rats in DZ and HZ groups were exchanged diets after 20 days. A part of rats in each group were killed at days 20, 50 and 70. The activities of alkaline phosphatase(ALP), 5'-nucleotidase(5'-NT) and copper-zinc-superoxidase dismutase(Cu-Zn-SOD), the zinc concentration in plasma and kidney were determined to assess the better indices for zinc nutrition. The results indicted that: The activities of ALP in DZ group at 20 d was significantly lower than that in the same group at the beginning, in the HZ group and in the HZP group, and increased significantly after the diet was changed to HZ diet after 30 days. The activities of 5'-NT in DZ group rats was decreasing with the extension of experimental period. These results indicated that the activities of ALP and 5'-NT were sensitive to zinc supplementation even though they were changed a little during zinc exhausted. The activity of ALP was decreasing with growing, and the activity of 5'-NT was increased with growing. Zinc concentration in plasma of DZ group was significantly lower than that of other groups which include DZ-HZ group at the 50th day, and it was also the lowest among groups at the end of experiment. Zinc concentration in the kidney of HZ-DZ group was significantly lower than that of HZ and DZ-HZ groups by the end of experiment. There were little changes of the activity of Cu-Zn SOD and the zinc content in kidney during the experiment period. These results indicated that the activities of both ALP and 5'-NT and plasma zinc were sensitive to zinc supplementacior and zinc deficiency.

[Priority of selenium incorporation into selenoproteins during selenium depletion in rats]

Male weanling Wistar rats were fed with either a basal selenium deficient diet (a Torula yeast based semisynthetic diet, containing Se 0.01 mg/kg) or a selenium sufficient diet supplemented with Se as Na2SeO3 (containing Se 0.5 mg/kg). Rats were killed after different weeks(0,1,2,4,8,12,15,17,19,20 and 24 respectively). Their organs were taken to observe the kinetic change of selenium concentration, the activities of intracellular glutathione peroxidase (cGPX), extracellular glutathione peroxidase (eGPX), and phospholipid hydroperoxide glutathione peroxidase (PHGPX) in different organs. The results showed that selenium levels and the activities of selenoenzyme in testis and pituitary were more resistant to selenium deficiency than other organs. During selenium deficiency, the utilization of selenium by PHGPX and deiodinase was prior to eGPX and cGPX, which suggested that the function of PHGPX and deiodinase were more important than that of eGPX and cGPX.