HOTAIR promotes inflammatory response after acute myocardium infarction by upregulating RAGE

OBJECTIVE

The aim of this study was to explore the role of HOTAIR in inflammatory response after acute myocardium infarction (AMI) and to investigate its underlying mechanism.

MATERIALS AND METHODS

The AMI model was first constructed in rats, and heart tissues were harvested. Expression levels of HOTAIR and receptor of advanced glycation end-products (RAGE) in rat heart were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The protein expression level of pEKR in rat heart was detected by Western blot. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rats were determined by enzyme-linked immunosorbent assay (ELISA). The hypoxia-induced H9C2 cells were used to construct the MI model in vitro. Meanwhile, the expression levels of HOTAIR and RAGE in H9C2 cells were detected. The levels of TNF-α and IL-6 in the culture medium were determined by ELISA. Rescue experiments were conducted by co-transfecting pcDNA-HOTAIR and si-RAGE in H9C2 cells. Subsequently, the levels of pERK, TNF-α, and IL-6 were detected.

RESULTS

The mRNA expression levels of HOTAIR and RAGE in the AMI group were significantly higher than those of the control group. Western blot showed remarkably higher protein levels of RAGE and pERK in AMI rats when compared with those of controls. Similarly, results of ELISA indicated that the levels of TNF-α and IL-6 in AMI rats were significantly higher than those of controls. Meanwhile, overexpression of HOTAIR in H9C2 cells remarkably elevated the expression levels of HOTAIR and RAGE. In addition, upregulated pERK, TNF-α, and IL-6 were observed in H9C2 cells overexpressing HOTAIR, which could be reversed by RAGE knockdown.

CONCLUSIONS

HOTAIR promotes inflammatory response after AMI by upregulating RAGE expression.

[Clinical classification and characteristics of alcoholic myocardial injury]

Objective: To explore the clinical classification and characteristics of patients with alcoholic myocardial injury in the early and late stages, and to improve the understanding of early diagnosis of alcoholic myocardial injury. Methods: From December 2016 to December 2018, a total of 102 patients with long-term history of excessive alcohol consumption, cardiovascular symptoms and evidence of myocardial injury who were admitted to the cardiology outpatient clinic of Hangzhou First People's Hospital, the Third People's Hospital of Yuhang, Dajiangdong Hospital, the Second People's Hospital of Fuyang, and the People's Hospital of Linan were enrolled. According to diagnostic criteria of alcoholic cardiomyopathy (ACM), the patients were divided into ACM group (36 cases) and non-ACM group (66 cases). The baseline data, electrocardiogram and echocardiography characteristics of the two groups were recorded and analyzed. Results: There was no significant difference in the baseline between the two groups (P>0.05), including consumption and duration of alcohol. The left ventricular end-diastolic and right ventricular diameters in ACM group were (59±5) mm and (24±4) mm, respectively, which were significantly higher than those in non-ACM group ((51±4)mm, (22±4) mm, P<0.001 and P=0.044) . The left ventricular ejection fraction in ACM group was 41%±4%, which was significantly lower than that of non-ACM group (63%±8%, P<0.001). The incidence of biatrial enlargement in non-ACM group was 57.58%, which was significantly higher than that of ACM group (36.11%, P=0.038). The incidence of atrial fibrillation in non-ACM group was 54.55%, which was significantly higher than that of ACM group (27.78%, P=0.009). The incidence of diastolic heart failure in non-ACM group was significantly higher than that of ACM group (P=0.005). Conclusions: ACM is characterized by ventricular enlargement, decreased ejection fraction and heart failure, while non-ACM may belong to the early stage of alcoholic myocardial injury, characterized by biatrial expansion, atrial fibrillation and diastolic insufficiency. Due to the lack of understanding and no clinical diagnostic criteria, non-ACM is prone to be missed diagnosed and misdiagnosed.

Production of intense uranium beams with inductive heating oven at Institute of Modern Physics

HIAF (High Intensity heavy ion Accelerator Facility) is a new accelerator complex under construction at the Institute of Modern Physics. As the main injector of this project, the high-charge-state ECR ion source needs to provide intense uranium beams, such as 700 eμA of U³⁵⁺. This requires the performance of metal ovens to be further improved so that the crucible can operate at an ultrahigh temperature for a long time without damage in a high magnetic field (>3 T). In order to meet these requirements, an inductive oven with special thermal shielding and support has been developed in the past two years. The off-line test result has shown that this oven can reach up to 2000 °C with ∼1.2 kW of heating power. After ∼5 days of continuous running on the SECRAL-II platform, the tantalum crucible survived. In this contribution, we will discuss the structure of this inductive oven and analyze the test results as well.

[Value of serum HBV RNA in HBeAg-negative patients with chronic hepatitis B]

Objective: To analyze serum HBV-RNA levels in patients with chronic hepatitis B whose serum HBV-DNA has dropped to undetected levels after treatment with entecavir, and to explore the correlation between HBV-RNA level and liver biochemical parameters, which lay the research foundation for the clinical significance of new serological marker HBV-RNA. Methods: HBeAg negatively detected 107 cases with chronic hepatitis B whose serum HBV-DNA test results were lower than detection level for six consecutive months after receiving standard nucleoside therapy for more than 12 months were included. HBV-RNA level was detected by Perkin-Elmer reagent. HBV-DNA level was detected by Roche Cobas. Hitachi automatic biochemical analyzer was used to detect ALT and AST. Architect chemiluminescence analyzer was used to detect HBsAg, HBeAg, anti-HBe and anti-HBc. RStudio software was performed to analyze the correlation between HBV-RNA level and liver biochemical parameters. Logistic regression was used to analyze the independent factors influencing HBV-RNA level. Results: The positive detection rate of serum HBV-RNA in patients with chronic hepatitis B whose serum HBV-DNA had dropped to undetected levels after ETV treatment was 22.43%. HBsAg, ALT and AST levels in HBV-RNA positive group were slightly higher than HBV-RNA negative group, while anti-HBc levels were slightly higher in HBV-RNA negative group. There was no difference in the level of anti-HBe between the HBV-RNA negative and the positive group. Logistic regression analysis showed that anti-HBc was an independent factor influencing the level of HBV-RNA detection (P = 0.021). Conclusion: HBV-RNA can be detected in some patients with chronic hepatitis B whose serum HBV-DNA level has dropped to undetected levels after ETV treatment. Serum HBV-RNA only comes from the direct transcription of cccDNA, so it is better than HBV-DNA and HBsAg to reflect cccDNA level or activity. Anti-HBc, as an independent factor influencing the level of HBV-RNA, may be used in combination as a new marker to predict the efficacy of antiviral therapy.

Band Structure of Wurtzite GaBiAs Nanowires

We report on the first successful growth of wurtzite (WZ) GaBiAs nanowires (NWs) and reveal the effects of Bi incorporation on the electronic band structure by using polarization-resolved optical spectroscopies performed on individual NWs. Experimental evidence of a decrease in the band-gap energy and an upward shift of the topmost three valence subbands upon the incorporation of Bi atoms is provided, whereas the symmetry and ordering of the valence band states remain unchanged, that is, Γ₉, Γ₇, and Γ₇ within the current range of Bi compositions. The extraordinary valence band structure of WZ GaBiAs NWs is explained by anisotropic hybridization and anticrossing between p-like Bi states and the extended valence band states of host WZ GaAs. Moreover, the incorporation of Bi into GaAs is found to significantly reduce the temperature sensitivity of the band-gap energy in WZ GaBiAs NWs. Our work therefore demonstrates that utilizing dilute bismide alloys provides new avenues for band-gap engineering and thus photonic engineering with NWs.

[Diagnostic value of endoscopic ultrasonography, fibroscan, acoustic radiation pulse imaging, serological index, and their combination for early stage liver cirrhosis]

Objective: To investigate the diagnostic value of endoscopic ultrasonography (EUS), Fibroscan, acoustic radiation force impulse (ARFI), and aspartate aminotransferase-to-platelet ratio (APRI) and their combination for early stage liver cirrhosis. Methods: Three hundred and twenty-two hospitalized patients who had been diagnosed with chronic viral liver disease from March 2016 to April 2018 were included. According to the clinical diagnosis, patients were divided into chronic hepatitis and the early stage liver cirrhosis group (Child-Pugh A grade). All patients were examined by Fibroscan to detect liver stiffness measurement (LSM), ARFI to detect liver virtual touch tissue quantification (VTQ) value, esophagogastroduodenoscopy and EUS to detect esophagogastric varices, laboratory and imaging examination. The index of EUS, Fibroscan, ARFI, and APRI was analyzed and the regression model was established by binary logistic regression, and the diagnostic efficacy of the above index and regression model for early stage of cirrhosis was evaluated by the area under a receiver operating characteristic curve (AUROCs). Results: An early stage cirrhosis group had significantly higher detection rate with EUS (esophagogastric varices), Fibroscan (LSM), ARFI (VTQ) and APRI than chronic hepatitis group [76.7% vs. 10.7%, 10.4 (7.8, 17.3) vs. 6.1 (5.2, 8.4) kPa, 1.71(1.48, 2.07) m/s vs. 1.25(1.14, 1.43) m/s and 0.65 (0.38, 1.15) vs. 0.38(0.26, 0.62), respectively]. The corresponding chi-square test were 140.86, Z = -9.069, Z = -9.948 and Z = -5.764, respectively and the differences were statistically significant (P < 0.01). The areas under the receiver operating characteristic curve and regression model were 0.830 (0.783 ~ 0.877), 0.793 (0.744 ~ 0.841), 0.821 (0.775 ~ 0.868), 0.686 (0.628 ~ 0.744) and 0.947 (0.925 ~ 0.969) for the diagnosis of early stage cirrhosis, respectively. Among them, the regression model of three indices (EUS, LSM and VTQ) had the largest AUROCs (0.947) and the corresponding sensitivity and specificity were 0.878 and 0.867, respectively. Conclusion: The combination of EUS, LSM and ARFI had a superior diagnostic value for early stage liver cirrhosis, and may improve the diagnosis rate and reduce the misdiagnosis rate.

Betatron radiation and emittance growth in plasma wakefield accelerators

Beam-driven plasma wakefield acceleration (PWFA) has demonstrated significant progress during the past two decades of research. The new Facility for Advanced Accelerator Experimental Tests (FACET) II, currently under construction, will provide 10 GeV electron beams with unprecedented parameters for the next generation of PWFA experiments. In the context of the FACET II facility, we present simulation results on expected betatron radiation and its potential application to diagnose emittance preservation and hosing instability in the upcoming PWFA experiments. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Producing multi-coloured bunches through beam-induced ionization injection in plasma wakefield accelerator

This paper discusses the properties of electron beams formed in plasma wakefield accelerators through ionization injection. In particular, the potential for generating a beam composed of co-located multi-colour beamlets is demonstrated in the case where the ionization is initiated by the evolving charge field of the drive beam itself. The physics of the processes of ionization and injection are explored through OSIRIS simulations. Experimental evidence showing similar features are presented from the data obtained in the E217 experiment at the FACET facility of the SLAC National Laboratory. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Mycobacterium tuberculosis Beijing genotype strains and unfavourable treatment outcomes: a systematic review and meta-analysis

OBJECTIVES

The Mycobacterium tuberculosis Beijing genotype was first described in 1995 and is now the predominant strain among patients with tuberculosis in many Asian countries. The rapid global spread of the Beijing genotype is receiving increasing attention because it can cause a higher risk of treatment failures. Our objective was to assess the association between the Beijing genotype and unfavourable treatment outcomes of tuberculosis.

METHODS

We searched for eligible studies through PubMed, Web of Science, Chinese National Knowledge Infrastructure and Wanfang Data. We included cohort studies that evaluated treatment outcomes and Beijing genotype strains. Participants were individuals with active pulmonary tuberculosis. The association between Beijing genotype and the risk of unfavourable treatment outcomes was assessed using the pooled odds ratios (ORs) with corresponding confidence intervals (CIs).

RESULTS

In total, 7489 tuberculosis patients were involved in the analysis. Patients infected with the Beijing genotype were more likely to have unfavourable treatment outcomes, with the OR of 2.04 (95% CI 1.52-2.75). The pooled OR was 2.33 (95% CI 1.71-3.16) for recurrence, 2.36 (95% CI 1.69-3.30) for relapse and 2.62 (95% CI 1.90-3.61) for treatment failure, respectively. Subgroup analysis revealed that Beijing genotype was a significant risk factor for unfavourable treatment outcomes in Asians (OR 2.28, 95% CI 1.82-2.86) or in drug-susceptible TB patients (OR 2.11, 95% CI 1.31-3.39). No significant association was observed among non-Asian populations (OR 1.17, 95% CI 0.73-1.86) or patients with multidrug-resistant (MDR) tuberculosis (OR 0.97, 95% CI 0.48-1.94).

CONCLUSIONS

Our results suggest that Mycobacterium tuberculosis Beijing genotype is associated with an increased risk of unfavourable treatment outcomes, including treatment failure and relapse.

The N-terminal sequence of murine PRMT5 variant 2 is required for Hsp70 interaction and CHIP ligase-mediated degradation

Protein arginine methyltransferase PRMT5 synthesizes the symmetric dimethylarginine in nuclear and cytoplasmic proteins such as histone H2A, H4 and several non-histone proteins that are required for a variety of biological processes. Currently, two splice variants (v1 and v2) of murine PRMT5 have been deposited in the NCBI sequence database, in which PRMT5-v1 and -v2 contain different 33 and 16 amino acids at the N-terminal sequences, respectively. Here we showed that murine PRMT5-v1 is stable, but PRMT5-v2 is constantly degraded through both the ubiquitin proteasome system (UPS) and the autophagic-lysosomal pathway (ALP) in an N-terminal sequence-dependent manner. Furthermore, inhibition of UPS and ALP elevated the stability of PRMT5-v2 that made it localized in the nucleus and the cytoplasm. In addition, PRMT5-v2 exhibited the enzyme activity to catalyze histone H2A and H4 methylation. Notably, we found that the heat shock protein (Hsp) 70 specially recognizes the N-terminal sequence of PRMT5-v2 and the carboxyl terminus of Hsp70-interacting protein (CHIP) is required for poly-ubiquitination and the degradation of PRMT5-v2. These results suggest that Hsp70/CHIP chaperone-mediated protein degradation system is crucial in the regulation of PRMT5-v2 turnover, which has the potential to balance the symmetrical arginine dimethylation in cells.

TNF-derived peptides inhibit tumour growth and metastasis through cytolytic effects on tumour lymphatics

Tumour necrosis factor (TNF) is a multi-functional cytokine with profound and diverse effects on physiology and pathology. Identifying the molecular determinants underlying the functions and pathogenic effects of TNF is key to understanding its mechanisms of action and identifying new therapeutic opportunities based on this important molecule. Previously, we showed that some evolutionarily conserved peptides derived from TNF could induce cell death (e.g. apoptosis and/or necrosis), a feature of immune defence mechanisms shared by many vertebrates. In this study, we demonstrated that necrosis-inducing peptide P16 kills human glioblastoma cancer cells and primary human hepatoma or renal cancer cells isolated from patients who had not responded to standard treatments. Importantly, we show that the necrosis-inducing peptide P1516 significantly improves survival by inhibiting tumour metastasis in a 4T1 breast cancer syngeneic graft mouse model. Because the lymphatic system is an important metastatic route in many cancers, we also tested the effect of TNF-derived peptides on monolayers of primary human lymphatic endothelial cells (hDLEC) and found that they increased junctional permeability by inducing cytoskeletal reorganization, gap junction formation and cell death. Transmission electron microscopy imaging evidence, structural analysis and in-vitro liposome leakage experiments strongly suggest that this killing is due to the cytolytic nature of these peptides. P1516 provides another example of a pro-cytotoxic TNF peptide that probably functions as a cryptic necrotic factor released by TNF degradation. Its ability to inhibit tumour metastasis and improve survival may form the basis of a novel approach to cancer therapy.

Evaluation and comparison of the diagnostic performance of routine blood tests in predicting liver fibrosis in chronic hepatitis B infection

Background & aims: Biopsy is the gold standard for staging liver fibrosis, but it may be accompanied by complications. As an alternative, non-invasive markers such as transient elastography (for liver fibrosis) and certain combinations of routine blood markers (liver function tests, full blood count) have been developed although their clinical significance remains controversial. Here, we compare the diagnostic values of non-invasive markers for liver fibrosis in patients with chronic hepatitis B infection. Methods: Transient elastography and routine laboratory tests were performed in 196 patients. Diagnostic performances were compared and were assessed based on the area under the curve (AUC) of a receiver operating characteristic (ROC) analysis. Results: Elevated GGT to platelet ratio (GPR), the fibrosis index FIB-4 [based on age, AST, platelets and ALT], platelet to lymphocyte ratio (PLR) and total bilirubin were independent predictors of liver stiffness defined by transient elastography (all P < 0.001). The AUCs of GPR in predicting both advanced fibrosis and cirrhosis were significantly larger than that of FIB-4 (P = 0.037 and P = 0.008, respectively) and AST-to-platelet ratio index (APRI) (P = 0.008 and P = 0.005). FIB-4, APRI and red cell volume distribution width-to-platelet ratio (RPR) had similar diagnostic values in discriminating different levels of liver fibrosis. Conclusions: GPR showed the best diagnostic value and RPR and PLR are easily available and inexpensive markers in evaluating fibrosis and cirrhosis. The diagnostic values of these laboratory markers are useful in diagnosing advanced fibrosis or cirrhosis, and in confirming the different levels of liver fibrosis.

Neuronal Expression of Junctional Adhesion Molecule-C is Essential for Retinal Thickness and Photoreceptor Survival

BACKGROUND

Photoreceptor cell death is a key pathology of retinal degeneration diseases. To date, the molecular mechanisms for this pathological process remain largely unclear. Junctional adhesion molecule-c (Jam-c) has been shown to play important roles in different biological events. However, its effect on retinal neuronal cells is unknown.

OBJECTIVE

To determine the effect of Jam-c on adult mouse eyes, particularly, on retinal structure, vasculature and photoreceptor cells, in order to explore potential important target molecules for ocular diseases.

METHODS

Jam-c global knockout mice, endothelial-specific and neuronal-specific Jam-c conditional knockout mice using Tie2-Cre and Nestin-Cre mice respectively were used in this study. Mouse eyes were harvested from the different groups and eye size examined. Cryosections of the eyes were made and stained with Hematoxylin and Eosin (H&E) and the thicknesses of retinal layers measured. Retinal blood vessels and cone and rod photoreceptors were analyzed using isolectin B4, peanut agglutinin and rhodopsin as markers respectively. In vivo Jam-c knockdown in mouse eyes was performed by intravitreal injection of Jam-c shRNA. Jam-c expression in the retinae was quantified by real-time PCR.

RESULTS

Global Jam-c gene deletion in mice resulted in smaller eyes and decreased the diameters of lens and iris. Jam-c-/- mice display marked thinning of the outer nuclear layer (ONL), less numbers of photoreceptor cells, and abnormal retinal vasculature. Importantly, neuronal-specific Jam-c deletion led to similar phenotype, whereas no obvious defect was observed in endothelial-specific Jam-c knockout mice. Moreover, Jam-c knockdown by shRNA also decreased ONL thickness and photoreceptor numbers.

CONCLUSION

We found that Jam-c is critically required for the normal size and retinal structure. Particularly, Jam-c plays important roles in maintaining the normal retinal thickness, vasculature and photoreceptor numbers. Jam-c thus may therefore have important roles in various ocular diseases.

[Research progress on exposure levels and toxic pathways of typical persistent organic pollutants in foods]

Dioxins, polybrominated diphenyl ethers, and benzo(a)pyrene are common organic pollutants in food. They have been of concern to academics and government administrations due to high residue and persistence, easy accumulation and strong harmful effects. The National Research Council of the United States of America published Toxicity Testing in the 21st Century: A Vision and Strategy in 2007, which proposed a new concept of toxicity testing that toxicity testing should take full consideration of population exposure data and base on in vitro tests, human cell lines, toxicity pathways and high-throughput screening. Meanwhile, systems biology, bioinformatics and rapid assay technologies will be used to better understand toxicity pathways-the cellular response pathways that can lead to adverse health effects when sufficient perturbing induced by chemicals exposure. The new toxicity testing strategy has changed the traditional testing pattern and has brought a wide impact on the international relevant fields. The European Union, the World Health Organization, and the United States Environmental Protection Agency, the Food and Drug Administration, and the National Center for Toxicological Research have organized relevant discussions and exploratory studies to address the new toxicity testing concept and how to evaluate and utilize the results of traditional toxicity test researches. Compared to the discussion, 'whether to do it', ten years ago, the question, 'how to do it', has become the concern of the current discussion. Therefore, how to respond to the concept of toxicity testing and how to effectively utilize and excavate traditional toxicity test data have been the focus of multi-disciplines and interdisciplinary academia such as toxicology, food hygiene and environmental science. Therefore, this article provides an overview of the exposure levels of dioxin, polybrominated diphenyl ethers and benzo[a]pyrene, which are typical persistent organic pollutants in food in China and the current research status of toxic pathways based on whole animal experiments. The exposure level, toxic effect and toxicity mechanism of three contaminants are analyzed and summarized in order to provide basis for future results based on the 21st century toxicity test compared with traditional tests and data mining analysis of these two kinds of data. Meanwhile, it also lays the foundation for the establishment of a toxicity testing framework based on exposure characteristics, toxic pathways, and biomarkers.

[Effect of Anluohuaxianwan on the expression of matrix metalloproteinases and their inhibitors in rat liver with fibrosis]

Objective: To investigate the effect of anluohuaxianwan (ALHXW) using rat model of carbon tetrachloride (CCl(4)) induced liver fibrosis on the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Methods: Thirty-six male Wistar rats were randomly assigned into control, model and treatment groups. Rats in the model and treatment groups were injected intraperitoneally with 40% CCl(4) (2 ml/kg), and the control group were given isotonic saline twice a week for six weeks. Meanwhile, the treatment group were gavaged with ALHXW solution daily (concentration 0.15 g/ml, 9.9 ml/kg) for 6 weeks, while the control and model groups were given isotonic saline once a day for 6 weeks. Serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured at the end of third and sixth week. At the end of six weeks, liver tissues were harvested for histopathological evaluation and the detection of mRNA and protein expression levels of MMP-2/13 and TIMP-1/2. According to different data, LSD method, parametric (one-way ANOVA) and non-parametric tests (Kruskal-Wallis H-test and Mann-Whitney U test) were used for statistical analysis. Results: Compared with the model group, ALHXW markedly alleviated liver injury in the treatment group, and thereby improved the general state of rats, liver and spleen morphological characteristics, and ALT and AST levels. Histopathological examination demonstrated that the extent of liver fibrosis was improved (2.75 ± 0.75 vs. 3.55 ± 0.69, P = 0.015) in the treatment group as compared with the model group. The mRNA and protein expression levels of MMP-13 in the treatment group were significantly higher than that of the model group (mRNA: 10.50 ± 7.64 vs. 4.40 ± 2.97, P = 0.029. Protein: 1.15 ± 0.09 vs. 0.78 ± 0.21, P = 0.016), whereas the mRNA and protein expression levels of MMP-2, TIMP-1/2 in the treatment group were significantly lower than that of the model group (mRNA: 4.55 ± 3.29 vs. 7.83 ± 4.19, P = 0.048; 1.66 ± 0.73 vs. 3.69 ± 2.78, P = 0.023; 2.25 ± 1.16 vs. 3.41 ± 1.51, P = 0.049; respectively. Protein: 0.44 ± 0.11 vs. 0.65 ± 0.05, P = 0.03; 0.69 ± 0.06 vs. 1.07 ± 0.21, P = 0.016; 0.46 ± 0.09 vs. 0.81 ± 0.13, P = 0.003; respectively). Conclusion: ALHXW exerts anti-liver fibrosis effects mainly by improving liver function, inhibiting the activation of hepatic stellate cells, enhancing the expression of MMP-13, and inhibiting the expression of MMP-2 and TIMP-1/2.

Phase Space Dynamics of a Plasma Wakefield Dechirper for Energy Spread Reduction

Plasma-based accelerators have made impressive progress in recent years. However, the beam energy spread obtained in these accelerators is still at the ∼1% level, nearly one order of magnitude larger than what is needed for challenging applications like coherent light sources or colliders. In plasma accelerators, the beam energy spread is mainly dominated by its energy chirp (longitudinally correlated energy spread). Here we demonstrate that when an initially chirped electron beam from a linac with a proper current profile is sent through a low-density plasma structure, the self-wake of the beam can significantly reduce its energy chirp and the overall energy spread. The resolution-limited energy spectrum measurements show at least a threefold reduction of the beam energy spread from 1.28% to 0.41% FWHM with a dechirping strength of ∼1  (MV/m)/(mm pC). Refined time-resolved phase space measurements, combined with high-fidelity three-dimensional particle-in-cell simulations, further indicate the real energy spread after the dechirper is only about 0.13% (FWHM), a factor of 10 reduction of the initial energy spread.

[A clinical study of haploidentical hematopoietic stem cell transplantation in the treatment of pediatric patients with acquired severe aplastic anemia: single center experience]

目的

探讨单倍型造血干细胞移植（haplo-HSCT）治疗儿童获得性重型再生障碍性贫血（SAA）的疗效。

方法

回顾性分析2011年12月1日至2017年12月1日接受haplo-HSCT的59例SAA患者。

结果

①全部59例SAA患儿中男37例、女22例，中位年龄4.5（1.2~14.8）岁，中位体重43（12~80）kg；SAA-Ⅰ型47例，SAA-Ⅱ型12例，26例为极重型再生障碍性贫血（VSAA）；首次移植56例，二次移植3例。②预处理选用白消安+环磷酰胺+抗胸腺细胞球蛋白（ATG）方案或白消安+氟达拉滨+环磷酰胺+ATG方案；采用环孢素A（CsA）+霉酚酸酯+甲氨蝶呤方案预防急性GVHD；回输单个核细胞中位数为15.60（7.74~21.04）×10⁸/kg，CD34⁺细胞中位数为4.86（3.74~7.14）×10⁶/kg。③全部59例患儿均获得中性粒细胞和血小板植入。中性粒细胞植入中位时间为13（10~19）d，血小板植入中位时间为19（9~62）d。④Ⅰ~Ⅱ、Ⅲ/Ⅳ度急性GVHD发生率分别为45.76%（27/59）、13.56%（8/59），慢性GVHD发生率为8.47%（5/59）。巨细胞病毒血症发生率为59.32%（35/59）、EB病毒血症发生率为28.81%（17/59）。⑤中位随访时间30（8~80）个月，57例无病存活，2例死亡（均死于GVHD），5年总生存率、无失败生存率均为（96.4±2.5）%。

结论

haplo-HSCT是儿童SAA疗效较好的治疗方法。

Robust regression for optimal individualized treatment rules

Because different patients may respond quite differently to the same drug or treatment, there is an increasing interest in discovering individualized treatment rules. In particular, there is an emerging need to find optimal individualized treatment rules, which would lead to the "best" clinical outcome. In this paper, we propose a new class of loss functions and estimators based on robust regression to estimate the optimal individualized treatment rules. Compared to existing estimation methods in the literature, the new estimators are novel and advantageous in the following aspects. First, they are robust against skewed, heterogeneous, heavy-tailed errors or outliers in data. Second, they are robust against a misspecification of the baseline function. Third, under some general situations, the new estimator coupled with the pinball loss approximately maximizes the outcome's conditional quantile instead of the conditional mean, which leads to a more robust optimal individualized treatment rule than the traditional mean-based estimators. Consistency and asymptotic normality of the proposed estimators are established. Their empirical performance is demonstrated via extensive simulation studies and an analysis of an AIDS data set.