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With the increasing demand for battery electric buses, the dual-motor coupling powertrain (DMCP) shows great advantages, but it makes the energy optimization problem more complex. To solve the hybrid system optimization problem, a stochastic model predictive control (SMPC) method is proposed to exploit the potential performance of DMCP, where the most critical issue is to improve the prediction accuracy and handle the uncertainties. After analyzing the typical velocity profiles, statistical properties are used to develop a novel Signed Markov Chain Monte Carlo (SMCMC) method that can enhance the accuracy of velocity prediction by more than 50%, compared to conventional Markov Chain methods. Next, considering the uncertainties present in various driving scenarios, the development of driving cycle recognition model based on fuzzy logic control (FLC) is introduced; this method permits to identify the current category of driving cycle rapidly. Then, dynamic programming (DP) is adopted to solve the rolling optimization problems in each finite horizon online, including necessary constraints of dynamic response. Finally, simulation results demonstrate that the proposed energy management strategy can address various daily driving cycles well, and can improve the energy performance by 6% under a generalized combination of driving conditions compared to preliminary rule-based control.

This paper studies political connections from the view of the social networks. We build social networks annually from 2009 to 2017, where firm leaders serve or served in the same government institu...

This paper examines how the strength of political connections affects innovation. Considering complex relationships between firms and governments as well as different powers of bureaucracy ranks, we model political connections of all Chinese listed firms as weighted social networks and measure their strength by network centralities. The empirical results show that firms with stronger political connections innovate more. This paper further identifies two possible mechanisms of this finding: political connections help firms get more government subsidies and intellectual capital, both of which are verified to promote innovation with statistical significance.

Glutathione S-transferases P1 (GSTP1) is a phase II detoxifying enzyme and increased expression of GSTP1 has been linked with acquired resistance to anti-cancer drugs. However, most anticancer drugs are not good substrates for GSTP1, suggesting that the contribution of GSTP1 to drug resistances might not be dependent on its capacity to detoxify chemicals or drugs. In the current study, we found a novel mechanism by which GSTP1 protects human breast cancer cells from adriamycin (ADR)-induced cell death and contributes to the drug resistance. GSTP1 protein level is very low in human breast cancer cell line MCF-7 but is high in ADR-resistant MCF-7/ADR cells. Under ADR treatment, MCF-7/ADR cells showed a higher autophagy level than MCF-7 cells. Overexpression of GSTP1 in MCF-7 cells by using the DNA transfection vector enhanced autophagy and down-regulation of GSTP1 through RNA interference in MCF-7/ADR cells decreased autophagy. When autophagy was prevented, GSTP1-induced ADR resistance reduced. We found that GSTP1 enhanced autophagy level in MCF-7 cells through interacting with p110α subunit of phosphatidylinositol-3-kinase (PI3K) and then inhibited PI3K/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) activity. Proline123, leucine160, and glutamine163, which located in C terminal of GSTP1, are essential for GSTP1 to interact with p110α, and the following autophagy and drug resistance regulation. Taken together, our findings demonstrate that high level of GSTP1 maintains resistance of breast cancer cells to ADR through promoting autophagy. These new molecular insights provide an important contribution to our better understanding the effect of GSTP1 on the resistance of tumors to chemotherapy.

The tumor-associated inflammatory microenvironment plays a pivotal role in human non-small cell lung cancer (NSCLC) development. FGFR1 and TLR4 involve in the regulation of inflammatory microenvironment of NSCLC.However, the relationship between the FGFR1 and TLR4 signaling and the mechanisms that involved in tumor-associated microenvironment are still unclear. We investigated the expression of FGFR1 and TLR4 in cancerous tissues and noncancerous lung tissues from 60 primary NSCLC patients using immunohistochemical staining. Three cell lines (A549, PC-9 and SK-MES-1) were used for in vitro studies. We demonstrated that the expression of FGFR1 and TLR4 was significantly correlated (r=0.504, p

In this paper we present a generalized configuration model with random triadic closure (GCTC). This model possesses five fundamental properties: large clustering coefficient, power law degree distribution, short path length, non-zero Pearson degree correlation, and existence of community structures. We analytically derive the Pearson degree correlation coefficient and the clustering coefficient of the proposed model. We select a few datasets of real-world networks. By simulation, we show that the GCTC model matches very well with the datasets in terms of Pearson degree correlations and clustering coefficients. We also test three well-known community detection algorithms on our model, the datasets and other three prevalent benchmark models. We show that the GCTC model performs equally well as the other three benchmark models. Finally, we perform influence diffusion on the GCTC model using the independent cascade model and the linear threshold model. We show that the influence spreads of the GCTC model are much closer to those of the datasets than the other benchmark models. This suggests that the GCTC model is a suitable tool to study network science problems where degree correlation or clustering plays an important role.

Yaping Zhang,1,2,* Ping Song,1,3,* Ruhui Zhang,1 Yake Yao,1 Lisha Shen,1 Qiang Ma,4 Jianying Zhou,1 Hua Zhou1 1Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, People’s Republic of China; 2Department of Respiratory and Critical Care Medicine, Shangyu People’s Hospital, Shaoxing, Zhejiang, 312300, People’s Republic of China; 3Department of Critical Care Medicine, Deqing People’s Hospital, Huzhou, Zhejiang, 313200, People’s Republic of China; 4Department of Respiratory Diseases, Yuhang Second People’s Hospital, Hangzhou, Zhejiang, 311100, People’s Republic of China*These authors contributed equally to this workCorrespondence: Hua Zhou; Jianying ZhouDepartment of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310003, People’s Republic of ChinaEmail zhouhua1@zju.edu.cn; zjyhz@zju.edu.cnPurpose: Parvimonas micra (P. micra) is a Gram-positive anaerobic bacterium distributed in the oral cavity, with a potential to become pathogenic causing lung abscess. Due to the lack of specificity of symptoms and the difficulty in culture, the diagnosis of lung abscess associated with P. micra is delayed. It is essential to elucidate the clinical characteristics of lung abscess associated with P. micra.Methods: From January 2019 to July 2020, five patients with chronic lung abscess associated with P. micra diagnosed by pathological biopsy and metagenomic next-generation sequencing (mNGS) were analyzed in this retrospective study.Results: Among the five patients, four had a history of smoking, three had periodontitis, and two had a history of drinking. The average course of the disease was 6.5 months. High-density flake-like or mass shadows with irregular boundaries were observed in the chest computed tomography (CT) images of the five patients, and liquefactive necrosis was detected in the middle of the lesions; however, no gas-liquid plane or cavity was noted, making it difficult to distinguish a lung cancer. The pathological biopsy of the five patients showed chronic inflammation of lung tissue, and P. micra was detected by mNGS in the biopsy or bronchoalveolar lavage fluid samples. Two patients were treated with amoxicillin-clavulanate, two had metronidazole, and one had moxifloxacin. Among them, four recovered after receiving antibiotic treatment, and the remaining one underwent surgical resection due to poor antibiotic treatment effect.Conclusion: Chronic lung abscess associated with P. micra, common in elderly male smokers with poor oral hygiene, is often diagnosed in a delayed manner and misdiagnosed as lung cancer. The mNGS technology is beneficial to the rapid determination of P. micra.Keywords: Parvimonas micra, P. micra, lung abscess, metagenomic next-generation sequencing, mNGS

Fructose 1, 6-diphosphate (FDP), a glycolytic intermediate，has been identified to possess antioxidant activities. Here we show the protective effect of FDP against alcohol-induced liver injury in mice and the underlying mechanisms. The in vivo experiments demonstrated that FDP, orally administered to mice, dose-dependently suppressed alcohol (50%, v/v, 12ml/kg)-induced increase of serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), serum triglyceride (TG) level and hepatic malondialdehyde (MDA) level. FDP also inhibited liver histological lesions induced by seven-day administration of alcohol to mice. In vitro study indicated that FDP inhibited ethanol-induced L02 cell apoptosis via reducing pro-caspase3 protein level and increasing poly ADP-ribose polymerase (PARP) cleavage. The mechanism analysis showed that FDP prevented ethanol-induced decrease of mouse antioxidant capability through inhibiting the reducion of the level of glutathione (GSH) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GSH-PX) in mouse livers, and suppressing the reducion of GSH level and SOD activity in L02 cells. FDP also enhanced alcohol metabolic rate through increasing alcohol dehydrogenase (ADH) activity and acetaldehyde dehydrogenase (ALDH) protein level, and down-regulating cytochrome p450 2E1 (CYP2E1). These results displayed that FDP protected mice from alcohol-induced liver injury, suggesting the potential activity of FDP in preventing alcoholic liver disease (ALD).

Background In our previous studies, we have indentified that 1,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ) can alleviate toluene diisocyanate-induced airway epithelial barrier disruption and we also found that vascular endothelial growth factor (VEGF) derived from airway epithelials cells could disrupt epithelial barrier. Objective The study aimed to investigate whether 1,25(OH) 2 D 3 can inhibit house dust mite (HDM) induced airway epithelial barrier dysfunction by regulating the VEGF pathway. Method The 16HBE and BEAS-2B cells were cultured and treated according to the experiment requirement. Trans Epithelial Electric Resistance (TEER), permeability of epithelial layer, and distribution and expression of junction proteins were used to evaluate the cell layer barrier function, Western Blot was used to evaluate the expression of junction proteins and phosphorylated Akt in the cells, RT-PCR and ELISA were used to evaluate the VEGF gene expression and protein release in the cells. Recombinant VEGF165 was used to determine the role of the VEGF pathway in the epithelial barrier function. Results HDM resulted in a decline in TEER and increase of cell permeability, following abnormal distribution and expression of junction proteins (E-Cadherin and zona occludens (ZO)-1), accompanied by a significant upregulation of VEGF and phosphorylated Akt, which were all partly recovered by treatment with either 1,25(OH) 2 D 3 or PI3K inhibitor LY294002. VEGF165-induced barrier dysfunction was accompanied by disruption of the epithelial E-cadherin and β-catenin, pretreatment of 1,25(OH) 2 D 3 and LY294002 markedly attenuated VEGF-induced airway barrier disruption in 16HBE cells. Conclusion 1,25(OH) 2 D 3 can alleviate HDM-induced airway epithelial barrier dysfunction by inhibiting PI3K pathway-dependent VEGF release.

In this study, cinnamic acid derivatives with pyridine ring were synthesized via Hantzsch reaction in order to expand conjugation system and their antioxidant abilities were tested. According to the evaluation results of their antioxidant properties, compounds 2 and 3 have similar antioxidant activity to prevent DNA from •OH– and Cu2+/GSH induced oxidation, demonstrating that 1,4-dihydropyridine and pyridine nucleus exhibit good resistance to oxidation while the substituents have little effect. In the meantime, the AAPH-induced oxidative DNA damage [AAPH=2,2′-azobis(2-methylpropionamidine)dihydrochloride] and trapping ABTS+• test show that N—H bond and large conjugation systems are the pivotal parts to improve the activities of antioxidant.

This study aims to explore relationships between return linkages on international supply chain, idiosyncratic volatility and abnormal returns in local markets. Empirically, focusing on the seven top U.S. high-technology firms and local market of their Taiwanese suppliers, we find significant daily return spillovers from U.S. stocks to the suppliers, electronic industry indices, market index, and non-electronic index in Taiwan, possibly resulting from fundamentals connections or investor sentiments diffusion. Furthermore, stocks strongly sensitive to the U.S. stocks, have high idiosyncratic volatility and a return premium. Moreover, we provide an external sensitivity factor for asset pricing in Taiwan.

Acute lung injury is the most serious and fatal complication of the elderly patients with hip fracture, but the mechanisms are unknown. Recent studies demonstrated the mitochondrial DNA (mtDNA) release was associated with lung injury after trauma. This study aimed to examine the differential release of mtDNA between younger and elderly rats suffering from hip fracture and to investigate the possible mechanism of mtDNA in the lung injury induced by hip fracture. In the first part of the study, we investigated the effects of hip fracture on the rats. The elderly and younger rats, respectively, received hip fracture operations. The degree of lung injury was evaluated, toll-like receptor 9 (TLR9) and nuclear factor kappa B (NF-κB) were determined using Western blot, and mtDNA were analyzed by fluorescent quantitative polymerase chain reaction. In the second part of the study, we investigated the effects of mtDNA on the rats. The elderly and younger rats directly received intravenous injections with mtDNA. After 24 h, the specimens were collected and detected as the first part. Hip fracture resulted in significant mtDNA release, TLR9 and NF-κB p65 expression, and lung injury in the rats. Meanwhile, the mtDNA injection could indirectly induce lung injury. Compared to the younger ones, the elderly rats suffered more serious lung injury after hip fracture and mtDNA injection. These results suggest that the lung injury induced by hip fracture may be involved with the mtDNA release and its TLR9/NF-κB pathway.

Cigarette smoke extracts (CSE) alter calpain-1 expression via ERK signaling pathway in bronchial epithelial cells. 1α,25-dihydroxyvitamin D3 (1,25D3) inhibits cigarette smoke-induced epithelial barrier disruption. This study was aimed to explore whether the 1,25D3 counteracted the CSE effects in a human bronchial epithelial cell line (16HBE). In particular, transepithelial electrical resistance (TER) and permeability, expression and distribution of E-cadherin and β-catenin, calpain-1 expression, and ERK phosphorylation were assessed in the CSE-stimulated 16HBE cells. The CSE induced the ERK phosphorylation, improved the calpain-1 expression, increased the distribution anomalies and the cleaving of E-cadherin and β-catenin, and resulted in the TER reduction and the permeability increase. The 1,25D3 reduced these pathological changes. The 1,25D3 mediated effects were associated with a reduced ERK phosphorylation. In conclusion, the present study provides compelling evidences that the 1,25D3 may be considered a possible valid therapeutic option in controlling the cigarette smoke-induced epithelial barrier disruption.

Cancer stem-like cells (CSCs) have been reported to play major roles in tumorigenesis, tumor relapse, and metastasis after therapy against colorectal carcinoma (CRC). Therefore, identification of colorectal CSC regulators could provide promising targets for CRC. Ligand-of-Numb protein X1 (LNX1) is one E3 ubiquitin ligase which mediates the ubiquitination and degradation of Numb. Although several studies indicate LNX1 could be a potential suppressor of cancer diseases, the functions of LNX1 in mediating cancer stemness remain poorly understood. In this study, LNX1 was identified as a negative regulator of cancer stemness in CRC, which was downregulated in colonospheres or side population (SP) cells. Furthermore, the coxsackievirus and adenovirus receptor (CXADR) was found to be one critical downstream mediator of cancer stemness regulated by LNX1. Interestingly, the anti-breast cancer drug tamoxifen was found to be an agonist of LNX1 and suppress cancer stemness in CRC. In sum, this study provided the evidences that LNX1 signaling plays important roles in regulating the stemness of colon cancer cells.

Apoptosis protease activating factor-1 (Apaf-1) and death-associated protein kinase (DAPK) are p53 pathway-related genes that play significant roles in the activation of caspases, which are involved in mitochondrial-mediated apoptosis. The present study aimed to confirm the role of hyper-methylation of the Apaf-1 and DAPK gene promoter regions in oral squamous cell carcinoma (OSCC) and the effect of the demethylation drug, 5-aza-2'-deoxycytidine (DAC). mRNA from 53 OSCC samples, 23 normal oral mucosa samples and Tca8113 human tongue carcinoma cell lines was detected using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The DNA from each sample was analyzed using methylation-specific PCR (MSP). The Tca8113 cells were demethylated using DAC and the demethylation and re-expression of Apaf-1 and DAPK were analyzed. The Apaf-1 and DAPK mRNA expression index was decreased in 51 (96.23%) and 50 (94.34%) cases, respectively, in the tumor tissues. Hypermethylation of the Apaf-1 and DAPK promoter regions was detected in 46 (86.79%) and 38 (71.69%) cases, respectively. Promoter hypermethylation of the two genes correlated with a decreased mRNA expression in the tumor tissues. Subsequent to being treated with DAC, Apaf-1 and DAPK were demethylated and re-expressed in the Tca8113 cells. Apaf-1 and DAPK promoter hypermethylation may be associated with low gene expression in OSCC. Furthermore, a loss of Apaf-1 and DAPK expression may recover following demethylation. The data provide evidence that methylation exists in OSCC and may play a role in the development of this disease.

Peer-to-Peer (P2P) plays an important role in the domain of Internet application, such as file sharing and instance communication. However, for the characteristic of bandwidth-intensive, P2P traffic identification is especially important in network management, which has been a hot topic in recent years. Based on the review of shortages of current existed technologies, a k-means algorithm based method was brought forward to identify the P2P traffic. For the reason that K-Means is one of the quickest and simplest clustering methods, it was selected as the core algorithm. In addition, the process of flow-information extraction and the descriptions of selected traffic attribute were also introduced in detail. Since the BT file-sharing traffic mainly runs over TCP, we only extract the flow-information of TCP connections. Finally, the experiments on 3 common used P2P applications, which are BitTorrent, BitSpirit and eMule, demonstrated the validity and efficiency of the method.

Improve the safety of cloud computing is important for widely using it in real application. For solving this problem, a security mechanism for cloud computing platform based on virtualization is proposed in this paper. The system structure is introduced in detail, which is mainly composed of two parts, behavior gathering module and behavior analyzing module. Then, the functional characteristics of all entities are described, and the communication mechanism of the system is also represented.

In our previous studies, we have indentified that 1,25-dihydroxyvitamin DThe study aimed to investigate whether 1,25(OH)The 16HBE and BEAS-2B cells were cultured and treated according to the experiment requirement. Trans Epithelial Electric Resistance (TEER), permeability of epithelial layer, and distribution and expression of junction proteins were used to evaluate the cell layer barrier function, Western Blot was used to evaluate the expression of junction proteins and phosphorylated Akt in the cells, RT-PCR and ELISA were used to evaluate the VEGF gene expression and protein release in the cells. Recombinant VEGF165 was used to determine the role of the VEGF pathway in the epithelial barrier function.HDM resulted in a decline in TEER and increase of cell permeability, following abnormal distribution and expression of junction proteins (E-Cadherin and zona occludens (ZO)-1), accompanied by a significant upregulation of VEGF and phosphorylated Akt, which were all partly recovered by treatment with either 1,25(OH)1,25(OH)

SUMMARY The development of network technology reveals the clear trend that mobile devices will soon be equipped with more and more network-based functions and services. This increase also results in more intrusions and attacks on mobile devices; therefore, mobile security mechanisms are becoming indispensable. In this paper, we propose a novel signature matching scheme for mobile security. This scheme not only emphasizes a small resource requirement and an optimal scan speed, which are both important for resource-limited mobile devices, but also focuses on practical features such as stable performance, fast signature set updates and hardware implementation. This scheme is based on the finite state machine (FSM) approach widely used for string matching. An SRAM-based two-level finite state machine (TFSM) solution is introduced to utilize the unbalanced transition distribution in the original FSM to decrease the memory requirement, and to shorten the critical path of the single-FSM solution. By adjusting the boundary of the two FSMs, optimum memory usage and throughput are obtainable. The hardware circuit of our scheme is designed and evaluated by both FPGA and ASIC technology. The result of FPGA evaluation shows that 2,168 unique patterns with a total of 32,776 characters are stored in 177.75 KB SelectRAM blocks of Xilinx XC4VLX40 FPGA and a 3.0 Gbps throughput is achieved. The result of ASIC evaluation with 180 nm-CMOS library shows a throughput of over 4.5 Gbps with 132 KB of SRAM. Because of the small amount of memory and logic cell requirements, as well as the scalability of our scheme, higher performance is achieved by instantiating several signature matching engines when more resources are provided.

Cigarette smoke extracts (CSE) alter calpain-1 expression via ERK signaling pathway in bronchial epithelial cells. 1α,25-dihydroxyvitamin D3 (1,25D3) inhibits cigarette smoke-induced epithelial barrier disruption. This study was aimed to explore whether the 1,25D3 counteracted the CSE effects in a human bronchial epithelial cell line (16HBE). In particular, transepithelial electrical resistance (TER) and permeability, expression and distribution of E-cadherin and β-catenin, calpain-1 expression, and ERK phosphorylation were assessed in the CSE-stimulated 16HBE cells. The CSE induced the ERK phosphorylation, improved the calpain-1 expression, increased the distribution anomalies and the cleaving of E-cadherin and β-catenin, and resulted in the TER reduction and the permeability increase. The 1,25D3 reduced these pathological changes. The 1,25D3 mediated effects were associated with a reduced ERK phosphorylation. In conclusion, the present study provides compelling evidences that the 1,25D3 may be considered a possible valid therapeutic option in controlling the cigarette smoke-induced epithelial barrier disruption.

Based on the analysis of several kinds of methods generally used to intercept network packets in different layers, a dynamic mechanism using NDIS intermediate drivers is proposed to protect web security, which can block malicious connection in real time. The mechanism is mainly composed of three components which include NDIS intermediate driver-based interception module, filter module and cooperation module. Characteristics of every component are also introduced. Then the system realization is discussed in detail. Finally, experiments results show that the system can detect attacks and intercept malicious packets effectively, and the time delay of the developed driver from intercepting to denying or passing data is small.

The aim of the reported study was to optimize the extraction process for ganoderma triterpenes and to investigate the in vivo inhibitory effect of ganoderma triterpenes on the genesis and progression of oral cancer. Single-factor and orthogonal methods were used to investigate the effects of extraction solvent, solvent amount, extraction time, extraction temperature, and number of extractions, on the extraction rate for ganoderma triterpenes. A golden hamster model with cheek pouch dynamic canceration was established to receive oral treatment of ganoderma triterpenes water solution. Animals were continuously monitored, oral tissue samples were collected for histopathologic examination, and changes in the expression of VEGF (vascular endothelial growth factor) and Caspase-3 were detected by immunohistochemical methods. Optimization of the experimental conditions allowed the identification of the optimal extraction conditions: 90% ethanol as the extraction solvent, a solvent amount by the liquid-material ratio of 35 mL/g, extraction time of 2 h and extraction temperature of 80 °C. Under these conditions, the average extraction rate of ganoderma triterpenes was 1.09%. Tests in golden hamsters showed that compared with the model group during the same period, animals in the treatment group had better conditions, constantly larger number of normal cases shown by histopathologic results (P < 0.01), and consistently smaller numbers of cases with paraplasm (P < 0.05). Immunohistochemical results showed that compared with the model group, the treatment group had significantly lower (P < 0.05) rates of positive VEGF expression in the normal state, simple epithelial hyperplasia, epithelial dysplasia or squamous cell carcinoma disease stages. Caspase-3 expression showed a tendency toward a gradual increase with the worsening of disease severity in each group. Compared with the model group, the treatment group had significantly lower (P < 0.05) rates of positive Caspase-3 in the normal state, simple epithelial hyperplasia, epithelial dysplasia or squamous cell carcinoma disease grades. Using the optimized extraction process, ganoderma triterpenes could be extracted with high efficiency, and the results of animal tests showed inhibitory effects of ganoderma triterpenes on oral mucosa cancer.

Intrusion detection techniques at the level of system processes are discussed, and a new method named V-AHD (Variable-length Average Hamming Distance) is presented, which can be used to monitor and calculate deviation to discriminate between normal and abnormal sequences of system calls. For the reason that fixed-length patterns can not describe the system behavior correctly and its inability to represent long meaningful substrings, the V-AHD method use Teiresias to get variable-length patterns and construct the normal set. Then the algorithm for detection is described in detail, and the pseudocode is also given. The method has some advantages, such as algorithm simplicity, low overhead of time, high accuracy and real-time detection. The prototype experiments with four attacks prove the validation of the method, which has high True Positive Rate and low False Positive Rate.

In this paper, a method based on peer-information to control BitTorrent (BT) traffic in distributed model is proposed. It is called peer-cache method. Through recording and analyzing the peer-information which is obtained from the BT signaling traffic, the BT file-sharing traffic related witht hese peers can be accurately identified and controlled even it is encrypted. As more and more forcibly encrypted BT trafficis generated by the clients, our peer-cache method is more comprehensive than the popular port-based and signaturebased traffic identification methods.

Gene targeting using short interfering RNA(siRNA) has become a common strategy to explore gene function because of its prominent efficacy and specificity. It is proven that the application of siRNA technology to gene therapy is effective. In this study, we constructed a siRNA expression plasmid against gene X-linked inhibitor of apoptosis (XIAP), and then used breast cancer cells MCF-7 to assess its functions. XIAP siRNA plasmid was constructed using an U6pro vector contained U6 promoter, After the plasmid had been transfected into MCF-7 cells and effected on the cell cycle, the expression change of XIAP was examined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The apoptosis of the transfected cells was analyzed by flow cytometry, and TUNEL method. The in vitro cellular growth activities were assayed by MTT incorporation. Twenty-four nude mice were randomly divided into 3 equal groups and were inoculated with electroinjection of blank plasmid, scrambled nucleotide control (control siRNA), or siRNA against XIAP subcutaneously respectively, then the appearance and size of tumors were observed. Four weeks later the mice were killed and the volumes of tumor were calculated so as to evaluate the therapeutic effects of siRNA against XIAP. The successful construction of siRNA against XIAP plasmid was identified with sequencing. After the siRNA expression vector was transfected into the MCF-7 cells, the expression of XIAP gene was inhibited significantly (by 90%). The cellular growth activities in the MCF-7 cells transfected with siRNA against XIAP plasmid decreased obviously. The siRNA against XIAP plasmid knocked down XIAP expression in MCF-7 cells obviously, arrested the cell cycle in G1 phase, inhibited cell proliferation significantly, and promoted cell apoptosis in a tendency. TUNEL assay and flow cytometry showed that the classic apoptosis characters of the MCF-7 cells transfected with siRNA against XIAP plasmid manifested an apoptosis rate of 77.2%, significantly higher than those in the control siRNA group and in the blank plasmid group (both p