Establishment of Cell Free Conversion System With Biotin-labelled Recombinant PrP^(sen) Expressed in E.coli

Objective To report a protocol using biotin-labelled PrP protein in cell free conversion assay instead of isotope. Methods A hamster PrP protein （HaPrP） was expressed in E. coli and purified with HIS-tag affinity chromatograph. After being labelled with biotin, HaPrP was mixed with PrP^sen preparation from scrapie strain 263K. Results Protease-resistant bands were detected after four-day incubation. Conclusion The new conversion model provides a reliable, easily handling, and environment-friendly method for studies of prion and transmissible spongiform encephalopathies.

Cell-Free大规模MIMO系统中基于传输时延的缓存策略研究

为了满足未来移动互联网中用户的超低时延和超高可靠需求,将无线缓存技术与无小区大规模多输入多输出系统相结合,设计了基于AP间协作缓存及区域流行度评估的缓存模型。推导出涉及AP分簇、协作缓存以及区域流行度的传输时延表达式,并将内容放置问题表述为最小化总内容传输时延问题。通过对优化问题的NP-hard和拟阵约束下次模单调性的证明,提出了基于贪婪算法的缓存部署优化策略。仿真结果表明,所提策略可有效降低系统内容传输时延和提升缓存命中率。

Diagnostic value of negative enrichment and immune fluorescence in situ hybridization for intraperitoneal free cancer cells of gastric cancer

Objective:To explore the intraperitoneal free cancer cell(IFCC)detection value of negative enrichment and immune fluorescence in situ hybridization(NEimFISH)on chromosomes(CEN)8/17.Methods:To verify the reliability of NEimFISH,29 gastric cancer tumors,their adjacent tissues and greater omental tissues were tested.Our study then included 105 gastric cancer patients for IFCC.We defined patients as IFCC-positive if a signal was detected,regardless of the detailed cancer cell numbers.A comparison of clinicopathological features was conducted among IFCC groups.We also compared the diagnosis value and peritoneal recurrence predictive value among different detection methods.The comparison of IFCC number was also conducted among different groups.Results:A cutoff of 2.5 positive cells could distinguish all benign tissue samples and 97%of malignant tissue samples in our study.Compared to intestinal gastric cancer,patients with diffuse gastric cancer tended to have more IFCCs(6 vs.4,P=0.002).The IFCC counts were often higher in the lymphovascular invasion positive group than negative group(3 vs.1,P=0.022).All IFCC samples that were considered positive using conventional cytology were also found to be positive using NEimFISH.When compared to conventional cytology and paraffin pathology,NEimFISH had a higher IFCC positive rate(68.9%)and higher one-year peritoneal recurrence predictive value with area under the curve(AUC)of 0.922.Conclusions:Gastric cancer could be effectively diagnosed by NEimFISH.The IFCC number found using NEimFISH on CEN8/17 is closely associated with Lauren type and vascular invasion of cancer.NEimFISH is a reliable detection modality with a higher positive detection rate,higher one-year peritoneal recurrence predictive value and quantitative features for IFCC of gastric cancer.

Effects of processing pH stimulation on cooperative bioleaching of chalcopyrite concentrate by free and attached cells

In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.

Deactivation Kinetics of Nitrile Hydratase in Free Resting Cells

Nitrile hydratase (NHase) is an important industrial enzyme used for acrylamide production from acrylonitrile.The deactivation kinetics of NHases in free resting cells of Rhodococcus sp.was presented based on a bi-steady state assumption.Effects of hydration temperature,product concentration and substrate concentration on NHase deactivation were investigated experimentally and correlated with a first order deactivation kinetics.The results showed that the hydration temperature and product concentration were major factors governing the deactivation of NHases under substrate-feeding conditions.When acrylamide concentration was higher than 250 g·L1,the deactivation of NHases became serious and the bi-steady state assumption was not applicable.When the hydration temperature was controlled at a relatively higher level such as 28°C,the total deactivation rate constant was about 2.8-fold of that at 20°C.

Effects of Chuanxiongqin hydrochloride on increasing the fluidity of brain cell membrane and scavenging free radicals in model rats with ischemia/reperfusion injury

BACKGROUND: The fluidity of cell membrane can be affected by various factors. Many experiments have confirmed that the ischemia/reperfusion of organic tissue can increase the contents of free radicals, which lead to high rigidity and low fluidity of cell membrane, and the conditions can be changed by Chuanxiongqin. OBJECTIVE: To observe the effect and mechanism of Chuanxiongqin hydrochloride on the fluidity of brain cell membrane in rat models of ischemia/reperfusion. DESIGN: A completely randomized controlled animal trial. SETTINGS: Institute of Brain Sciences; Department of Physiology, Medical College, Datong University. MATERIALS: Twenty male grade Ⅰ Wistar rats of 170-220 g were randomly divided into model group (n =10) and control group (n =10). Chuanxiongqin hydrochloride (molecular mass was 172.2) was purchased from the National Institute for the Control of Pharmaceutical and Biological Products (batch number: 0817-9803); Spin labelers: 5-doxyl-stearlic acid methylester (5DS), 16-doxyl-stearlic acid methylester (16DS), xanthine, xanthine oxidase (XOD) and 5,5-dimeth-1-pyrroline- N-oxide (DMPO) from Sigma Company; Bruker ESP 300 electron paramagnetic resonance (EPR) spectrometer by Bruker Company (Germany). METHODS: The experiments were carried out in the State Key Laboratory of Natural and Biomimetic Drugs, Peking University from June 2001 to July 2002. In the model group, rats were made into models of cerebral ischemia by 30-minute ligation and 2-hour reperfusion of common carotid arteries; The rats in the control group were not made into models. The order parameter (S) and rotational correlation time (τc) were detected with the ESR spectrometer by means of spin labeling. The greater the S and τc, the smaller the fluidity. Meanwhile, the clearance rate of free radicals was detected with ESR spin trapping. The measurement data were compared using the t test. MAIN OUTCOME MEASURES: The S, τc and clearance rates of O2 · and OH· free radicals were compared between the model group and control group. RESULTS: The S and τc in the model group [0.738 4±0.003 5; (8.472±0.027)×10-10 s/circle] were obviously different from those in the control group [0.683 9±0.008 3; (7.945±0.082)×10-10 s/circle, t =5.731, 5.918, P < 0.05], which suggested that ischemia/reperfusion injury decreased the fluidity of brain cell membrane. After adding Chuanxiongqin hydrochloride, there were no obvious differences between the model group [0.688 5±0.030 5; (7.886±0.341)×10-10 s/circle] and control group (P > 0.05), indicating that Chuanxiongqin hydrochloride could recover the fluidity of brain cell membrane after ischemia/reperfusion injury close to the level in the normal control group. Chuanxiongqin hydrochloride could directly scavenge the O2 · and OH· free radicals, and the maximal clearance rates were 83.92% and 44.99% respectively. CONCLUSION: Chuanxiongqin hydrochloride increases the fluidity of membrane of ischemia-injured brain cell by scavenging both O2 ·and OH· free radicals.

Comparison of peritoneal free gastric cancer cells' detecting rates between laparoscopically assisted and open radical gastrectomy

Objective： To compare laparoscopic gastrectomy and conventional surgery on the dissemination and seeding of tumor cells. Methods：Intraoperative peritoneal lavage cytologic examination was performed in 65 patients with gastric cancer, during laparoscopic gastrectomy （n = 34） and conventional surgery （n = 31）. Cytology was examined twice, immediately after opening the peritoneal cavity and just before closing the abdomen. Saline was poured into the peritoneal cavity, and 100 ml fluid was retrieved after irrigation. Laparoscopic instruments were lavaged after surgery with 100 ml saline. Carbon dioxide （COz） was derived through the trocar side orifice after pneumoperitoneum during laparoscopic gastrectomy and filtered through 100 ml saline. Cytologic examination of the filtrate was performed after the filtration process. Results： The incidence of positive cytology during laparoscopic surgery was 32.26% in the preoperative lavage and 22.58% in the postoperative lavage. The incidence of positive cytology during conventional surgery was 41.18% before lavage and 26.47% after lavage. Only one positive cytology was detected in the CO2 filtrate gas. The incidence of positive cytology in the lavage of the instruments during laparoscopic surgery was 6.45 %. Conclusion： During gastric laparoscopic surgery, CO2 pneumoperitoneum does not affect tumor cell dissemination and seeding. In this study, laparoscopic techniques used in gastric cancer surgery were not associated with a higher risk for intraperitoneal dissemination of cancer cells than the conventional surgery.

THE RELATIONSHIP BETWEEN SEROSAL TYPES, PATHOLOGICAL CHARACTERISTICS AND FREE CANCER CELLS IN THE PERITONEAL CAVITY OF GASTRIC CANCER PATIENTS

The relationship between free cancer cells and the pathological characteristics of gastric cancer were studied. Of 100 cases of gastric cancer, free cancer cells in the peritoneal cavity were detected in 32 cases (32%). Free cancer cells were most often found in tendonoid (62.2%) and colour diffused (60.0%) serosal types. When the area of serosal invasion was over 20 cm, the positive free cancer cell rate was 56.6% and only 2.5% if below 20 cm. Free cancer cells were related to the depth of cancer infiltration, often found in the S2 and S3 invasion layers, as well as to the pathological characteristics of gastric cancer. Free cancer cells were often seen in infiltrated type cancer, histologically poorly differentiated or undifferentiated adenocarcinoma. and nest or diffused growth types. In patients without peritoneal metastasis (P0), the positive rate was 26.1%. This study proved that Chen's serosal classification is correct and useful in assessing whether the cancer cells have penetrated through the serosa or not during surgery. Different treatments should be used in the cases with different serosal types. In addition to surgery, destruction of free cancer cells should be considered in tendonoid and colour diffused serosal types, so as to prevent peritoneal metastasis.

Comparison of conventional and inverted structures in fullerene-free organic solar cells

A n-type small molecule DC-IDT2E with 4,4,9,9-tetrakis（4-hexylphenyl）-indaceno[1,2-b：5,6-bt]dithiophene as a central building block, furan as rr-bridges, and 1,1 -dicyanomethylene-3-indanone as end acceptor groups, was synthesized and used as an electron acceptor in solution-processed organic solar cells （OSCs）. DC-IDT2F exhibited good thermal stability, broad and strong absorption in 500-850 rim, a narrow bandgap of 1.54 eV, LUMO of-3.88 eV, HOMO of-5.44 eV and an electron mobility of 6.5 × 10-4 cm2/（V.s）. DC-IDT2F-based OSCs with conventional and inverted structures exhibited power conversion efficiencies of 2.26 and 3.08% respec- tively. The effect of vertical phase separation and morphology of the active layer on the device performance in the two structures was studied.

异质无蜂窝MIMO绿色通信网络

异质无蜂窝多天线(Multiple-Input Multiple-Output,MIMO)系统是未来移动网络发展的方向之一,也是极具节能潜力的高效通信系统。本文首先对异质无蜂窝MIMO系统的整体构架进行了介绍,从整体的角度分析该网络的具体构架和节能潜力,随后从绿色网络部署与协作、网络运行与调度以及用户接入、高能效MIMO收发机技术和传输与多址等方面介绍了基本原理和潜在节能增益。随着信息超材料的发展,一些全新的异质MIMO收发机逐渐展现了其在能效方面的优势,合理利用这些新型的收发机技术将有效提高系统能效。除了硬件带来的增益之外,异质无蜂窝组网的增益主要来源于各个接入点的协作传输所形成的超大规模MIMO,而这也带来了更加复杂的信号传输模式,同时受限于有限的算力资源,系统不可能无限协作,因此需要对该系统的接入点部署策略和协作方式进行全新的研究。在完成部署之后,由于用户在空间和时间上的通信需求变化较大,还可以利用深度学习等技术对用户的行为进行一定程度的预测,并在空间和时间上对通信设备的运行状态进行调整,在满足通信指标的同时提高系统的能效。最后,用户的多址接入与传输方式则是整个异质无蜂窝MIMO系统的基础,新型的速率分割多址接入(Rate-Splitting Multiple Access,RSMA)技术可以有效对抗干扰,而针对异质无蜂窝MIMO系统的传输波束赋形也需要进行全新的设计以适应RSMA技术和异质的MIMO设备。本文还同时讨论了以上各个方面的可能设计以及未来研究方向。

基于位置分配的去蜂窝massive MIMO系统导频分配功率控制算法

针对去蜂窝(cell free,CF)大规模多输入多输出(multiple-input multiple-output,MIMO)系统中存在严重的导频污染问题,提出了一种基于位置分配的贪婪导频分配功率控制算法(greedy pilot assignment based on location with pilot power control,GPABL with PPC).首先,遵循相邻用户不分配相同导频序列的原则进行贪婪导频分配(greedy pilot assignment,GPA);然后,在导频分配的基础上叠加了导频功率控制,选择合理的导频功率控制系数减小信道估计的均方误差.仿真结果表明,将两种方式结合起来进行导频优化,系统的吞吐能力有所提升.

系统免疫炎症指数对根治性放疗Ⅲ期肺鳞癌患者长期生存的预测价值

目的探讨系统免疫炎症指数(SII)对接受根治性放疗的Ⅲ期肺鳞癌患者长期生存的预测价值。方法回顾性收集接受根治性放疗的Ⅲ期肺鳞癌患者的临床资料。计算患者放疗前1周内的SII及相关炎症指标,同时应用X-Tile软件确定最佳截断值。分析患者的生存情况以及SII对患者总生存(OS)及无进展生存(PFS)的影响。结果共纳入了453例患者,低SII组336例(<1277.3),高SII组117例(≥1277.3)。高SII组的中位OS和中位PFS均较低SII组缩短(OS:20.8个月vs.31.0个月,Log-rankχ2=18.015,P<0.01;PFS:13.0个月vs.21.0个月,Log-rankχ2=15.062,P<0.01)。多因素Cox回归分析显示,高SII是患者OS(HR=1.628,95%CI:1.294~2.047,P<0.001)和PFS(HR=1.559,95%CI:1.240~1.961,P<0.001)的独立危险因素,其他的影响因素包括较晚的TNM分期、放疗疗效欠佳,HALP评分下降。结论SII可作为接受根治性放疗Ⅲ期肺鳞癌患者长期生存的评价指标,SII升高提示预后较差。

Prediction of peritoneal free cancer cells in gastric cancer patients by golden-angle radial sampling dynamic contrast-enhanced magnetic resonance imaging

Objectiveperitoneal free cancer cells can negatively impact disease progression and patient outcomes in gastric cancer. This study aimed to investigate the feasibility of using golden-angle radial sampling dynamic contrast-enhanced magnetic resonance imaging (GRASP DCE-MRI) to predict the presence of peritoneal free cancer cells in gastric cancer patients.MethodsAll enrolled patients were consecutively divided into analysis and validation groups. Preoperative magnetic resonance imaging (MRI) scans and perfusion were performed in patients with gastric cancer undergoing surgery, and peritoneal lavage specimens were collected for examination. Based on the peritoneal lavage cytology (PLC) results, patients were divided into negative and positive lavage fluid groups. The data collected included clinical and MR information. A nomogram prediction model was constructed to predict the positive rate of peritoneal lavage fluid, and the validity of the model was verified based on data from the verification group.ResultsThere was no statistical difference between the proportion of PLC-positive cases predicted by GRASP DCE-MR and the actual PLC test. MR tumor stage, tumor thickness, and perfusion parameter Tofts-Ketty model volume transfer constant (Ktrans) were independent predictors of positive peritoneal lavage fluid. The nomogram model featured a concordance index (C-index) of 0.785 and 0.742 for the modeling and validation groups, respectively.ConclusionsGRASP DCE-MR could effectively predict peritoneal free cancer cells in gastric cancer patients. The nomogram model constructed using these predictors may help clinicians to better predict the risk of peritoneal free cancer cells being present in gastric cancer patients.

佐利替尼一线治疗EGFR突变NSCLC伴中枢神经系统转移2例报告

目的探讨佐利替尼一线治疗具有原发表皮生长因子受体(EGFR)突变的非小细胞肺癌(NSCLC)伴中枢神经系统转移患者的疗效。方法2例患者均为一线使用佐利替尼,通过实体瘤的疗效评价标准RECIST v1.1和神经系统肿瘤脑转移RANO-BM标准评估肿瘤治疗反应。结果病例1基线伴多发脑转移,EGFR exon 19del突变,佐利替尼治疗51.4个月后仍维持肺部病灶部分缓解(PR)、颅内病灶完全缓解(CR)。病例2基线单个脑转移病灶,EGFR exon 19del突变,佐利替尼治疗期间达到肺部病灶PR、颅内病灶CR,13.7个月后肺部疾病进展(PD),新发单个脑转移病灶,综合评效PD。病例1出现3级不良反应,为皮肤干燥,其余主要为皮疹、肝功能异常、腹泻,不良反应总体可控。结论佐利替尼对EGFR突变NSCLC伴中枢神经系统转移患者有较好的颅内及颅外病灶的控制效果,与EVEREST研究一致,可作为一线初始治疗的选择。

低精度ADC下无小区大规模MIMO系统的频谱效率研究

无小区大规模多输入多输出(cell-free massive multiple-input multiple-output,CF-mMIMO)系统的覆盖区域内随机部署了大量分布式接入点(access points,APs)在同一时间频率资源中服务所有的用户,可显著提升系统通信容量,是6G网络中最具潜力的使能技术之一。然而,大量AP处配备高精度模数转换器(analog-to-digital converters,ADCs)导致的高功耗与硬件成本,限制了CF-mMIMO系统的实际部署。为了有效地降低硬件成本,本文研究了低精度ADCs下CF-mMIMO系统的上行链路频谱效率(spectral efficiency,SE)。在不完美的信道估计下,利用加性量化噪声(additive quantization noise model,AQNM)模型和最大比合并(maximal ratio combining,MRC)接收机滤波器,推导了CF-mMIMO系统中用户上行可达速率的闭式表达式,并基于该表达式分析了AP数量、用户传输功率以及ADCs精度等系统参数对SE的影响。为了最大化CF-mMIMO系统的SE,提出了一种低精度ADCs下贪婪导频分配算法抑制导频污染。将导频分配建模为最大-最小导频优化问题,通过迭代更新速率最小用户的导频序列,使其所受导频污染的影响最小,从而最大化该用户的可达速率。最后,将配备低精度ADC的CFmMIMO系统与传统完美精度ADC系统进行性能比较。数值仿真结果表明,系统配备5位低精度ADCs时的SE逼近完美精度ADCs,增加AP端天线数可以弥补低精度ADCs导致的性能退化。此外,所提算法不仅有效抑制了导频污染,还缩小了用户之间的速率差距,提升了系统的95%用户SE。

室内自由小区VLC协作的用户接入和功率动态调整方法

针对室内自由小区VLC网络照明和吞吐量联合优化困难的问题,该文提出VLC协作用户接入和功率动态调整(VCUA-DPA)方法。在用户接入阶段,设计考虑网络的负载均衡、用户速率需求和协作小区数目限制的用户和VLC协作的用户接入算法;在功率分配阶段,设计联合优化照明均匀度和系统吞吐量的功率动态调整分配算法。仿真结果表明,所提VCUA-DPA在明显提升系统吞吐量的同时能优化室内照明均匀度。

Emerging role of non-invasive and liquid biopsy biomarkers in pancreatic cancer

A global increase in the incidence of pancreatic cancer(PanCa)presents a major concern and health burden.The traditional tissue-based diagnostic techniques provided a major way forward for molecular diagnostics;however,they face limitations based on diagnosis-associated difficulties and concerns surrounding tissue availability in the clinical setting.Late disease development with asymptomatic behavior is a drawback in the case of existing diagnostic procedures.The capability of cell free markers in discriminating PanCa from autoimmune pancreatitis and chronic pancreatitis along with other precancerous lesions can be a boon to clinicians.Early-stage diagnosis of PanCa can be achieved only if these biomarkers specifically discriminate the non-carcinogenic disease stage from malignancy with respect to tumor stages.In this review,we comprehensively described the non-invasive disease detection approaches and why these approaches are gaining popularity for their early-stage diagnostic capability and associated clinical feasibility.

不同无血清培养体系对人脐带间充质干细胞生物学功能的影响

目的 探讨3种不同无血清培养体系对人脐带间充质干细胞(hUC-MSC)体外培养的生物学功能的影响。方法 取3株脐带组织,各分3组实验组,经贴壁法分别置于3组不同无血清培养体系(A组:纯化学成分合成的无血清培养体系,B组:血小板裂解物+基础培养基的无血清培养体系,C组:纤维蛋白原包被+含重组人蛋白质的无血清培养体系)中培养至第3代,比较其细胞增殖能力、细胞表型、三系分化能力以及免疫调节功能。结果 3组实验组细胞均呈长而扁平的梭形,贴壁生长,大小均一。其增殖曲线趋势相似,A组和B组P2、P3代次的增殖能力优于C组(P均<0.05)。3组实验组细胞均符合国际干细胞协会对hUC-MSC细胞表面标志物鉴定的要求,A组和B组P3代次的CD29和CD90的表达量均高于C组(P均<0.05),并且3组实验组均具有三系分化能力。3组实验组中P3代次的T淋巴细胞增殖率、Th1和Th17细胞亚群分泌的细胞因子比例均低于对照组,调节性T细胞(CD4+CD25+FOXP3+)比例均高于对照组,而3组实验组之间两两比较差异无统计学意义(P均> 0.05)。结论 3种不同无血清培养体系的hUC-MSC均能保持其基本的生物学特性和免疫调节活性,纯化学成分合成的无血清培养体系和血小板裂解物+基础培养基的无血清培养体系的增殖能力和细胞表面标志物表达均优于纤维蛋白原包被+含重组人蛋白质的无血清培养体系。

无小区大规模MIMO系统中基于图着色的导频分配与功率控制算法

无小区大规模MIMO(Cell-Free Massive MIMO,CF-mMIMO)系统中大量的无线接入点在同一时间频率资源中服务所有的用户,具有较高的网络覆盖率和频谱效率,是下一代无线通信的前沿技术之一。然而,正交导频数量的限制以及用户信道质量的差异造成了较严重的用户间干扰。为了优化这一干扰问题,本文提出了无小区大规模MIMO系统中基于图着色的导频分配与功率控制算法。利用基于图着色的导频分配算法降低导频污染,提高了信道估计精度。在此基础上,通过最大-最小功率控制算法降低多用户同频干扰,满足了系统中用户的混合服务质量需求。数值仿真结果表明:所提出的基于图着色的导频分配与功率控制算法可以显著提高系统的95%用户频谱效率以及最小用户速率,较好抑制了CF-mMIMO系统中的用户间干扰。

Cell-free systems in the new age of synthetic biology

The advent of synthetic biology has ushered in new applications of cell-free transcription-translation systems. These cell-free systems are reconstituted using cellular proteins, and are amenable to modular control of their composition. Here, we discuss the historical advance- ment of cell-free systems, as well as their new applications in the rapid design of synthetic genetic circuits and components, directed evolution ofbiomolecules, diagnosis of infectious diseases, and synthesis of vaccines. Finally, we present our vision on the future direction of cell-free synthetic biology.