正电子湮没谱表征热处理工艺对聚碳酸酯力学性能的影响

考察了退火和淬火2种热处理方法所用的不同热处理温度和时间对聚碳酸酯力学性能的影响,并采用正电子湮没谱分析经过不同热处理工艺后聚碳酸酯内部自由体积的含量。结果表明,在玻璃化转变温度附近及以上进行一定时间的淬火可通过增大内部自由体积含量和尺寸来显著改善聚碳酸酯的韧性,降低材料的屈服强度和弯曲强度,提高缺口冲击强度和拉伸强度。在玻璃化转变温度以下,淬火不能改变材料内部的自由体积,不能提高材料的韧性。退火只能降低材料内部自由体积的含量和尺寸,但不受温度和时间的影响,且材料的拉伸强度、断裂伸长率和缺口冲击强度大幅降低。

Integrated design and performance optimization of three-electrode sliding discharge plasma power supply

The three-electrode sliding dielectric barrier discharge(TES-DBD) plasma actuator significantly enhances the ionization rate and momentum exchange between charged particles and neutral particles by incorporating a parallel DC electrode into the standard DBD design. This design improves the body force and induced jet velocity while allowing flexible control of the induced jet angle, overcoming the limitations of discharge extension and uncontrollable direction in traditional DBD plasma actuators. An integrated plasma power supply has been designed specifically for TES-DBD plasma actuators, streamlining the power supply management. The methodology involves designing the circuit topology for the TES-DBD power supply, followed by simulating and validating its operating principles using Multisim software. The operational performance of the power supply is evaluated through a comprehensive analysis of its electrical,thermal, and aerodynamic properties specific to TES-DBD plasma actuation.

Quality-adjusted time without symptoms or toxicity analysis of haploidentical-related donor vs.identical sibling donor hematopoietic stem cell transplantation in acute myeloid leukemia

Objective:We aimed to compare the quality-adjusted time without symptoms or toxicity(Q-TWiST)in acute myeloid leukemia(AML)patients who received haploidentical-related donor(HID)and identical sibling donor(ISD)hematopoietic stem cell transplantation(HSCT).Methods:Five clinical health states were defined:toxicity(TOX),acute graft-versus-host disease(GVHD),chronic GVHD(cGVHD),time without symptoms and toxicity(TWiST)and relapse(REL).The equation used in this study was as follows:Q-TWiST=UTOX×TOX+UTWiST×TWiST+UREL×REL+UaGVHD×aGVHD+UcGVHD×cGVHD.Results:A total of 239 AML patients were enrolled.We established a mathematical model,i.e.,Q-TWiST HID HSCT>Q-TWiST ISD HSCT,to explore the range of utility coefficients satisfying the inequality.Based on the raw data,the utility coefficient is equivalent to the following inequality:10.57067UTOX-46.27733UREL+105.9374+3.388078UaGVHD-210.8198UcGVHD>0.The model showed that when UTOX,UREL,and UaGVHD were within the range of 0-1,as well as when UcGVHD was within the range of 0-0.569,the inequality Q-TWiST HID HSCT>Q-TWiST ISD HSCT was valid.According to the results of the ChiCTR1800016972 study,the median coefficients of TOX,acute GVHD(aGVHD),and cGVHD were 0.56(0.41-0.76),0.56(0.47-0.72),and 0.54(0.37-0.79),respectively.We selected a series of specific examples of the coefficients,i.e.,UTOX=0.5,UREL=0.05,UaGVHD-0.5,and UcGVHD-0.5.The Q-TWiST values of ISD and HID HSCT were 896 and 900 d,respectively(P=0.470).Conclusions:We first observed that Q-TWiST was comparable between AML patients receiving HID HSCT and those receiving ISD HSCT.

基于数值模拟的注射成型聚碳酸酯热/流动残余应力的壁厚特性

分别基于线性黏弹性模型和可压缩黏弹本构模型,采用相应的有限差分法和有限体积法作为控制方程的离散方法,以计算注射成型制品的流动残余应力和热残余应力。实现了对3 mm,7 mm和11 mm厚度注射成型聚碳酸酯平板的流动残余应力和热残余应力的数值模拟,并结合注射成型实验,分析了薄壁/厚壁制件流动残余应力、热残余应力和总残余应力的分布规律差异。计算结果表明,热残余应力区主要围绕平板边缘分布,中心区域的热残余应力明显低于边缘部分。随壁厚的增加,热残余应力逐渐上升,高残余应力分布面积明显增加,当壁厚从3 mm增加到11 mm,分布面积至少增加2倍以上;流动残余应力均表现为沿熔体流动方向递减的规律。随壁厚的增加,流动残余应力显著降低。当壁厚从3 mm增加到11 mm,最大流动残余应力从15 MPa降低到1.5 MPa,下降幅度达到90%;随着壁厚的增加,流动残余应力对平板总残余应力的贡献逐渐降低,热残余应力的贡献则逐渐增大。对于3 mm薄壁制件,流动残余应力占绝对主导地位;当平板厚度增加至7 mm时,近浇口区流动残余应力主导,远浇口区热残余应力主导;对于11 mm厚壁制件,热残余应力占绝对主导地位。不同壁厚平板的残余应力分布的数值模拟与实验结果吻合度较好,表明文中的数值模拟方法可以有效计算残余应力。

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with BALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT);furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

注塑压缩成型工艺对聚甲基丙烯酸甲酯-聚碳酸酯复合平板残余应力的影响

基于光弹法研究了聚碳酸酯(PC)、聚甲基丙烯酸甲酯(PMMA)两种材料的二次注射压缩成型中不同工艺参数,包括保压压力、保压时间、熔体温度、模具温度及压缩距离等对PMMA-PC复合平板制件残余应力的影响。结果表明,随保压压力的增大、保压时间的延长,残余应力呈现先减小后增大趋势;增加熔体温度和压缩距离会降低复合平板内的残余应力。模具温度的升高会使复合平板的残余应力逐渐增大,原因在于模内不对称冷却加剧了复合平板内部的残余热应力,当模具温度为70～80℃时,复合平板内残余应力较小且分布均匀。所研究的工艺参数中,模具温度和熔体温度对复合平板的残余应力影响最为显著。

免疫治疗相关生物标志物在消化道肿瘤中的应用

以程序性死亡-1(programmed death-1,PD-1)及程序性死亡配体1(programmed death-ligand 1,PD-L1)等免疫检查点抑制剂为代表的免疫治疗,使多种消化道肿瘤如胃癌、直肠癌、肝癌等能够获得持续缓解和生存获益,尤其是对有转移或者复发的患者获益更多。但并非所有胃肠道肿瘤的患者对抗PD-1和抗PD-L1的治疗均有较好的反应。因此亟需其他生物标志物来识别对治疗有效和无效的患者,以更好地预测其临床疗效。PD-L1的表达已逐渐成为预测免疫治疗疗效的潜在生物标志物,但仅依靠PD-L1不足以对患者可能的临床结果进行分类。其他生物分子,如肿瘤突变负荷(tumor mutational burden,TMB)、微卫星不稳定(microsatellite instability,MSI)及循环肿瘤DNA(circulating tumor DNA,ctDNA)等也在进一步探索中。但由于这些分子自身的局限性,目前在消化系统肿瘤免疫治疗中尚缺乏较好的生物标志物来实现患者识别和筛选,尤其是肝癌。本文将对已发现的生物标志物进行总结,以期为临床治疗和探索其他新的生物标志物奠定基础。

Sodium decorated net-Y nanosheet for hydrogen storage and adsorption mechanism: A first-principles study

Using first-principles calculations based on density functional theory(DFT),we investigate the potential hydrogen storage capacity of the Na-decorated net-Y single layer nanosheet.For double-side Na decoration,the average binding energy is 1.54 eV,which is much larger than the cohesive energy of 1.13 eV for bulk Na.A maximum of four H2 molecules can be adsorbed around each Na with average adsorption energies of 0.25–0.32 eV/H2.Also,H2 storage gravimetric of 8.85 wt%is obtained,and this meets the U.S.Department of Energy(DOE)ultimate target.These results are instrumental in seeking a promising hydrogen energy carrier.

Associations of sleeping patterns and isotemporal substitution of other behavior with the prevalence of CKD in Chinese adults

Studies have found a U-shaped relationship between sleep duration and chronic kidney disease(CKD)risk,but limited research evaluated the association of reallocating excessive sleep to other behavior with CKD.We included 104538 participants from the nationwide cohort of the Risk Evaluation of Cancers in Chinese Diabetic Individuals:A Longitudinal Study,with self-reported time of daily-life behavior.Using isotemporal substitution models,we found that substituting 1 h of sleeping with sitting,walking,or moderate-to-vigorous physical activity was associated with a lower CKD prevalence.Leisure-time physical activity displacement was associated with a greater prevalence reduction than occupational physical activity in working population.In stratified analysis,a lower CKD prevalence related to substitution toward physical activity was found in long sleepers.More pronounced correlations were observed in long sleepers with diabetes than in those with prediabetes,and they benefited from other behavior substitutions toward a more active way.The U-shaped association between sleep duration and CKD prevalence implied the potential effects of insufficient and excessive sleep on the kidneys,in which the pernicious link with oversleep could be reversed by time reallocation to physical activity.The divergence in the predicted effect on CKD following time reallocation to behavior of different domains and intensities and in subpopulations with diverse metabolic statuses underlined the importance of optimizing sleeping patterns and adjusting integral behavioral composition.

Early-life famine exposure,adulthood obesity patterns,and risk of low-energy fracture

Malnutrition in early life increases the risk of osteoporosis,but the association of early-life undernutrition combined with adulthood obesity patterns with low-energy fracture remains unknown.This study included 5323 community-dwelling subjects aged⩾40 years from China.Early-life famine exposure was identified based on the participants’birth dates.General obesity was assessed using the body mass index(BMI),and abdominal obesity was evaluated with the waist-to-hip ratio(WHR).Low-energy fracture was defined as fracture occurring after the age of⩾40 typically caused by falls from standing height or lower.Compared to the nonexposed group,the group with fetal,childhood,and adolescence famine exposure was associated with an increased risk of fracture in women with odds ratios(ORs)and 95%confidence intervals(CIs)of 3.55(1.57–8.05),3.90(1.57–9.71),and 3.53(1.05–11.88),respectively,but not in men.Significant interactions were observed between fetal famine exposure and general obesity with fracture among women(P for interaction=0.0008).Furthermore,compared with the groups with normal BMI and WHR,the group of women who underwent fetal famine exposure and had both general and abdominal obesity had the highest risk of fracture(OR,95%CI:3.32,1.17–9.40).These results indicate that early-life famine exposure interacts with adulthood general obesity and significantly increases the risk of low-energy fracture later in life in women.

ERRATUM TO:Cholesterol homeostasis regulated by ABCA1 is critical for retinal ganglion cell survival

Erratum to:SCIENCE CHINA Life Sciences,Volume 66,Issue 2:211-225(2022),https://doi.org/10.1007/s11427-021-2126-2 This paper contains an error in Figure 4C,where the representative images of filipin staining of retinal sections from 6-month-old mice were misused.We provide the correct picture for Figure 4C as follows.The statistical result in Figure 4D was corrected as well.This new Figure 4 does not affect the conclusion of this article.

Comparison of clinical features of nephrotic syndrome after haploidentical and matched donor hematopoietic stem cell transplantation

To the Editor:Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is one of the most effective options for hematological diseases.However,allo-HSCT treatment can cause serious complications.Post-transplant kidney damage is an important complication.In this study,we retrospectively analyzed the frequency of nephrotic syndrome(NS)after allo-HSCT and compared the frequency and clinical characteristics of NS between haploidentical donor(HID)and matched donor(MD)HSCT(including matched sibling donors[MSD]and unrelated donors[URD]).

Cholesterol homeostasis regulated by ABCA1 is critical for retinal ganglion cell survival

Genome-wide association studies have suggested a link between primary open-angle glaucoma and the function of ABCA1.ABCA1 is a key regulator of cholesterol efflux and the biogenesis of high-density lipoprotein(HDL) particles. Here, we showed that the POAG risk allele near ABCA1 attenuated ABCA1 expression in cultured cells. Consistently, POAG patients exhibited lower ABCA1 expression, reduced HDL, and higher cholesterol in white blood cells. Ablation of Abca1 in mice failed to form HDL, leading to elevated cholesterol levels in the retina. Counting retinal ganglion cells(RGCs) by using an artificial intelligence(AI) program revealed that Abca1-deficient mice progressively lost RGCs with age. Single-cell RNA sequencing(scRNA-seq) revealed aberrant oxidative phosphorylation in the Abca1-/-retina, as well as activation of the mTORC1 signaling pathway and suppression of autophagy. Treatment of Abca1-/-mice using atorvastatin reduced the cholesterol level in the retina,thereby improving metabolism and protecting RGCs from death. Collectively, we show that lower ABCA1 expression and lower HDL are risk factors for POAG. Accumulated cholesterol in the Abca1-/-retina causes profound aberrant metabolism, leading to a POAG-like phenotype that can be prevented by atorvastatin. Our findings establish statin use as a preventive treatment for POAG associated with lower ABCA1 expression.

METTL3-mediated m^(6)A modification of HMGA2 mRNA promotes subretinal fibrosis and epithelial-mesenchymal transition

Subretinal fibrosis is a major cause of the poor visual prognosis for patients with neovascular age-related macular degeneration(nAMD).Myofibroblasts originated from retinal pigment epithelial(RPE)cells through epithelial-mesenchymal transition(EMT)contribute to the fibrosis formation.N^(6)-Methyladenosine(m^(6)A)modification has been implicated in the EMT process and multiple fibrotic diseases.The role of m^(6)A modification in EMT-related subretinal fibrosis has not yet been elucidated.In this study,we found that during subretinal fibrosis in the mouse model of laser-induced choroidal neovascularization,METTL3 was upregulated in RPE cells.Through m^(6)A epitranscriptomic microarray and further verification,high-mobility group AT-hook 2(HMGA2)was identified as thekey downstream target of METTL3,subsequently activating potent EMT-inducing transcription factor SNAIL.Finally,by subretinal injections of adeno-associated virus vectors,we confirmed that METTL3 deficiency in RPE cells could efficiently attenuate subretinal fibrosis in vivo.In conclusion,our present research identified an epigenetic mechanism of METTL3-m^(6)A-HMGA2 in subretinal fibrosis and EMT of RPE cells,providing a novel therapeutic target for subretinal fibrosis secondary to nAMD.

Bridging chimeric antigen receptor T-cell before transplantation improves prognosis of relapsed/refractory B-cell acute lymphoblastic leukemia

To the Editor:For recipients with relapsed/refractory(R/R)B-cell acute lymphoblastic leukemia(B-ALL),allogeneic hematopoietic stem cell transplantation(allo-HSCT)often fails to provide them with a satisfactory prognosis.The chimeric antigen receptor T(CAR-T)cells are proven to be safe and effective for these patients.[1]But there are few published studies assessing the advantages of CAR-T compared to traditional chemotherapy as a bridging treatment followed by HSCT.Consequently,we conducted this study to confirm whether children and young adult R/R B-ALL patients with CAR-T therapy could expect a better post-HSCT prognosis,compared to R/R patients only receiving traditional chemotherapy before transplantation.

单倍型分析技术研究进展

单倍型是指共存于单条染色体上的一系列遗传变异位点的组合,每条染色体都有自己独特的单倍型。单倍型分析技术作为一种常用的数据分析方法,是寻找单染色体上杂合SNP变异位点的有效方法,也对挖掘致病基因、寻找疾病治疗新方法有重要作用。它主要包括间接推断法和直接实验法。文中介绍了各种单倍型分析方法及应用,尤其详细介绍了单分子稀释法和保留邻近性的转座酶测序法,同时对单倍型分析技术的应用前景进行了展望。

Comparison analysis between haplo identical stem cell transplantation and matched sibling donor stem cell transplantation for high-risk acute myeloid leukemia in first complete remission

In order to compare the effect between haploidentical(HID) stem cell transplantation(HSCT) and matched sibling donor(MSD)stem cell transplantation for high-risk acute myeloid leukemia(AML) in first complete remission status(CR1), we retrospectively studied 170 cases who received stem cell transplantation from Jan 2008 to Jul 2015 in Peking University People's Hospital. We divided all cases into MSD group(43 cases) and HID(127 cases) group. Patients in HID and MSD group displayed similar baseline characteristics except for age distribution. There were no statistic differences for overall survival(OS), cumulative incidence of relapse, leukemia free survival(LFS), transplantation related mortality(TRM) between HID and MSD group. The 3-year OS, LFS for all patients was 63.9% and 59.7% respectively. Multivariate analysis showed that grade III-IV acute graft versus host disease(aGVHD) was an independent risk factor for treatment related mortality(HR=8.134, 95% CI:3.210–20.611, P<0.001), monosomy/complex chromosomal karyotype and white blood cell count more than 50×109 L-1 were two independent factors for relapse(HR=1.533, 95% CI: 1.040–2.260, P=0.031)(HR=1.004, 95% CI: 1.001–1.008, P=0.015).Grade III-IV aGVHD was an independent factor for mortality(HR=3.184, 95% CI: 1.718–5.902, P<0.001). These results demonstrated some risk factors for high-risk AML leukemia transplantation and indicated for AML patients in CR1 status, haplo stem cell transplantation could have the same therapeutic effect as MSD transplantation.

Interferon-α salvage treatment is effective for patients with acute leukemia/myelodysplastic syndrome with unsatisfactory response to minimal residual disease-directed donor lymphocyte infusion after allogeneic hematopoietic stem cell transplantation

The efficacy of salvage interferon-α(IFN-α) treatment was investigated in patients with unsatisfactory response to minimal residual disease (MRD)-directed donor lymphocyte infusion (DLI)(n=24). Patients who did not become MRD-negative at 1 month after DLI were those with unsatisfactory response and were eligible to receive salvage IFN-α treatment within 3 months of DLI. Recombinant human IFN-α-2b injections were subcutaneously administered 2–3 times a week for 6 months. Nine (37.5%), 6 (25.0%), and 3 (12.5%) patients became MRD-negative at 1, 2, and>2 months after the salvage IFN-α treatment, respectively. Two-year cumulative incidences of relapse and non-relapse mortality were 35.9% and 8.3%, respectively. Two-year probabilities of event-free survival, disease-free survival, and overall survival were 51.6%, 54.3%, and 68.0%, respectively. Outcomes of patients subjected to salvage IFN-α treatment after DLI were significantly better than those with persistent MRD without IFN-α treatment. Moreover, clinical outcomes were comparable between the salvage DLI and IFN-α treatment groups. Thus, salvage IFN-α treatment may help improve the outcome of patients with unsatisfactory responses to MRD-directed DLI and could be a potential salvage treatment for these patients after allogeneic hematopoietic stem cell transplantation.

Improved clinical outcomes of rhG-CSF-mobilized blood and marrow haploidentical transplantation compared to propensity score-matched rhG-CSF-primed peripheral blood stem cell haploidentical transplantation:a multicenter study

The effects of haploidentical rhG-CSF-mobilized blood and marrow transplantation(HBMT) on hematological malignances are well established. Previous prospective single-center studies have demonstrated better survival after HBMT versus haploidentical rhG-CSF-mobilized peripheral blood stem cell transplantation(HPBSCT) for acute leukemia(AL) not in remission(NR) or in more than the second complete remission(>CR2). To test the hypothesis that HBMT is still superior to HPBSCT for patients with AL, multiple myeloma(MM), or non-Hodgkin lymphoma(NHL) in CR1/CR2 and for patients with chronic myeloid leukemia in the first and second chronic phase lacking a matched donor, we designed a propensity score method-based multicenter study.Hematopoietic recovery, acute graft-versus-host disease(aGVHD), and chronic GVHD were comparable between the HBMT group(n=168) and the HPBSCT group(n=42). No significant differences were found in non-relapse mortality rate(20.17%±3.58%and 27.24%±7.16%, P=0.18) or relapse rate(19.96%±3.72% and 28.49%±8.25%, P=0.32) between the HBMT group and the HPBSCT group. HBMT recipients had better overall survival(65.0%±4.2% and 54.2%±8.3%, P=0.037) and disease-free survival(59.9%±4.6% and 44.3%±8.7%, P=0.051). Multivariate analysis showed that HPBSCT was associated with poorer DFS(HR(95%CI), 1.639(0.995–2.699), P=0.052). Our comparisons showed that HBMT was superior to HPBSCT as a post-remission treatment for patients lacking an identical donor.

Minimal residual disease-directed immunotherapy for high-risk myelodysplastic syndrome after allogeneic hematopoietic stem cell transplantation

The efficacy of minimal residual disease (MRD)-directed immunotherapy,including interferon-α (IFN-α) treatment and chemotherapy plus granulocyte colony-stimulating factor-primed donor leukocyte infusion (chemo-DLI),was investigated in patients with high-risk myelodysplastic syndrome (MDS) who were MRD-positive after allogeneic hematopoietic stem cell transplantation (allo-HSCT).High-risk MDS patients who received non-T-cell-depleted allo-HSCT at the Peking University Institute of Hematology and were MRD-positive after ailo-HSCT were studied (n =47).The MRD-positive status was considered if leukemia-associated aberrant immune phenotypes or Wilms' tumor gene 1 expression is present in a single bone marrow sample.The cumulative incidence of the relapse and non-relapse mortality 2 years after immunotherapy were 14.5% and 21.4% (P=0.377)and 9.1% and 0.0% (P=0.985) for patients in the IFN-α and chemo-DLI groups,respectively.The probability of disease-free and overall survival 2 years after immunotherapy were 76.4% and 78.6% (P =0.891) and 84.3% and 84.6% (P=0.972) for patients in the IFN-α and chemo-DLI groups,respectively.Persistent MRD after immunotherapy was associated with poor survival.Thus,the MRD-directed immunotherapy was effective for patients with high-risk MDS who were MRD-positive after alIo-HSCT,and the efficacy was comparable between chemo-DLI and IFN-α treatment.