User QoS-Based Optimized Handover Algorithm for Wireless Networks.

Due to the development of wireless network technology, various applications relying on good network quality are widely used on mobile devices. Taking the commonly used video streaming service as an example, a network with high throughput and low packet loss rate can meet the service requirements. When the moving distance of the mobile device is greater than the signal coverage of the AP, it will trigger the handover process to connect to another AP, and cause the network to disconnect and reconnect instantaneously. However, frequently triggering the handover procedure will cause a significant drop in network performance and affect the operation of application services. In order to solve this problem, this paper proposes the OHA and OHAQR. The OHA considers whether the signal quality is good or bad, and uses the corresponding HM method to solve the problem of frequent handover procedures. The OHAQR integrates the QoS requirements of the throughput and packet loss rate into the OHA with the Q-handover score, to provide high-performance handover services with QoS. Our experimental results show that the OHA and OHAQR have 13 and 15 handovers in a high-density scenario, respectively, and are better than the other two methods. The actual throughput and packet loss rate of the OHAQR are 123 Mbps and 5%, respectively, and the network performance is better than that of other methods. The proposed method shows excellent performance in ensuring the network QoS requirements and reducing the number of handover procedures.

Gold-Catalyzed [3+2]-Annulations of α-Aryl Diazoketones with the Tetrasubstituted Alkenes of Cyclopentadienes: High Stereoselectivity and Enantioselectivity.

This work reports gold-catalyzed [3+2]-annulations of α-diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3-dihydrofurans with high regio- and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]-annulations with α-diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral forms of gold and phosphoric acid. Our mechanistic analysis supports that cyclopentadienes serve as nucleophiles to attack gold carbenes at the more substituted alkenes, yielding gold enolates that complex with chiral phosphoric acid to enhance the enantioselectivity.

[Research Progress on the Mechanism of PI3K/AKT/mTOR Signaling Pathway in Multiple Myeloma --Review].

PI3K/AKT/mTOR signaling pathway is of great significance in the development and prognosis of tumors, and is closely related to the pathogenesis of multiple myeloma (MM). PI3K/AKT/mTOR signaling pathway can participate in the regulation of MM through multichannel and multitarget, such as regulating the tumor microenvironment of MM cells survival, affecting tumor development and migration, regulating the proliferation, apoptosis and autophagy of MM cells. It have shown that after the PI3K/AKT/mTOR signaling pathway is inhibited, the apoptosis and autophagy of MM cells are activated, which promote the death of MM cells and inhibit the metastasis and recurrence of MM cells. Therefore, indepth study of the mechanism of PI3K/AKT/mTOR signaling pathway in MM is helpful to elucidate the pathogenesis and prognosis of MM.

[Research Progress on Effect of Bone Marrow Microenvironment Regulated by IL-6/IL-6R/JAK2/STAT3 Pathway on Biological Behavior of Multiple Myeloma--Review].

Multiple myeloma (MM) is a malignant disease with abnormal proliferation of clonal plasma cells. The development of the disease shows a vast heterogeneity, which is closely related to the interaction between MM cells and bone marrow microenvironment (BMM). The interleukin-6 (IL-6)/interleukin-6 receptor (IL-6R)/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway can regulate the transcription of related soluble factors in BMM, promote the proliferation, anti-apoptosis, drug resistance and guide related bone destruction of MM cells. This article reviews the research progress on the effect of BMM regulated by IL-6/IL-6R/JAK2/STAT3 pathway on the biological behavior of MM, in order to provide new research ideas for targeted therapy and precise therapy of MM.

Two Epstein-Barr virus-related serologic antibody tests in nasopharyngeal carcinoma screening: results from the initial phase of a cluster randomized controlled trial in Southern China.

A nasopharyngeal carcinoma (NPC) mass screening trial using a combination of immunoglobulin A antibodies to Epstein-Barr virus capsid antigen and nuclear antigen-1 by enzyme-linked immunosorbent assay in addition to indirect mirror examination in the nasopharynx and/or lymphatic palpation (IMLP) was conducted in southern China. Cantonese aged 30-59 years residing in 2 cities randomly selected by cluster sampling, Sihui and Zhongshan, were invited to participate in this screening from May 2008 through May 2010. Participants were offered fiberoptic endoscopy examination and/or pathologic biopsy if their serologic tests reached our predefined level of high risk or if results from the physical examination indicated possible cancer (i.e., were IMLP positive). A total of 28,688 individuals were voluntarily screened in the initial round. The overall NPC detection rate was 0.14% (41/28,688) with an early diagnosis rate of 68.3% (28/41) during the first year of follow-up. Thirty-eight of 41 cases (92.7%) were detected among the high-risk group, and 7 of 41 cases (17.1%) were detected among the IMLP-positive group. The 2 Epstein-Barr virus serologic tests by enzyme-linked immunosorbent assay could be a feasible alternative for NPC screening in endemic areas. Further follow-up is needed to examine whether screening has an effect on decreasing mortality from NPC in these areas.

[Mechanisms of Extracellular Vesicles Involved in Multiple Myeloma --Review].

Multiple myeloma (MM) is a common hematologic tumor characterized by malignant proliferation of clonal plasma cells, the exact pathogenesis of which is not yet fully understood. The extracellular vesicles (EV) are structures released by cells into their surroundings that do not have a functional nucleus and can communicate between cells or deliver biologically active proteins and nucleic acids to target cells. EV play an important role in the interaction between myeloma cells and the bone marrow microenvironment, and they can promote MM progression. In this paper, we summarize the recent research progress in the mechanism of action of EV on MM in order to provide inspiration for exploring new strategies for MM treatment and prognostic stratification.

[A dynamic study on titer of EB virus VCA/IgA and EA/IgA in nasopharygeal carcinoma patients].

OBJECTIVE: To analyze the change of EB virus VCA/IgA and EA/IgA titer during the development of nasopharyngeal carcinoma (NPC), and the role in screening for NPC. METHODS: VCA/IgA and EA/IgA were monitored in a period of 12 years by immunoenzymatic titration from the sera of 54 NPC patients after primary serological screening. RESULTS: VCA/IgA and EA/IgA titer had shown gradual increment 1 - 7 years before NPC was pathologically diagnosed. The mean titer of VCA/IgA was 1:21.04, 7 - 4 years before diagnosis. VCA/IgA titer ascended quickly within 3 years before diagnosis. The geometric mean titer (GMT) of VCA/IgA and EA/IgA were 1:76.86 and 1:6.49 when NPC was diagnosed, which descended quickly after radiotherapy and, in 4 years, approached the average titer of VCA/IgA positive population. CONCLUSION: VCA/IgA titer rises uninterruptedly 3 years before NPC is diagnosed pathologically in most patients but their EA/IgA titer rises slowly. The detection of VCA/IgA titer can be used to find early NPC, whereas EA/IgA can not. The pre-clinical phase of NPC is 3 years according to this dynamic study.

[Detection of serum Epstein-Barr virus antibody level by ELISA in normal populations and nasopharyngeal carcinoma patients in Zhongshan City of China].

OBJECTIVE: To understand the distribution of Epstein-Barr virus (EBV) antibodies, namely EBNA 1/IgA, ZEBRA/IgA, EBNA 1/IgG in the populations of different ages or genders in Zhongshan City of Guangdong Province, China. METHOD: A total of 484 serum samples were obtained from the population of Zhongshan City including 16 patients with nasopharyngeal carcinoma (NPC) and were assayed with enzyme-linked immunosorbent assay (ELISA) for EBV antibodies. RESULTS: The serum antibody level of EBNA1/IgA, represented by its relative optical density value abbreviated as D(lambda), was 0.726 +/- 0.541 in male and 0.563 +/- 0.340 in female subjects, showing significant difference (P<0.001). The level of ZEBRA/IgG in the male subjects was significantly lower than that of the female subjects (0.709 +/- 0.480 vs 0.829 +/- 0.480, P<0.01). EBNA1/IgG levels differed little between the male and the female subjects, being 0.781 +/- 0.285 and 0.784 +/- 0.302 respectively (P<0.05). The positivity rate of ZEBRA/IgG was obviously related to the subjects' ages with a correlation factor of 0.766 (P<0.05), and NPC patients had significantly higher levels of the 3 antibodies than did the healthy subjects (P<0.01). CONCLUSIONS: The serum levels of these 3 antibodies fluctuate within a limited range in different age groups or between genders, significant increasing in NPC group and therefore may help the diagnosis of NPC. It can be imperative to set differently critical values of EBV antibody for different population groups to facilitate nasopharyngeal carcinoma (NPC) diagnosis and high-risk screening.

[Six anti-Epstein-Barr virus antibodies in healthy adults in a high risk area of nasopharyngeal carcinoma].

BACKGROUND AND OBJECTIVE: Nasopharyngeal carcinoma (NPC), with a remarkable geographic distribution, is consistently associated with Epstein-Barr virus (EBV) infection, and almost all NPC patients have sustained high levels of serum antibodies against EBV. This study was to compare the levels of six anti-EBV antibodies in healthy natives of Zhongshan (a high-incidence area of NPC) with those in provisional migrants from foreign provinces (low-incidence areas of NPC), and to illustrate the relationship between EBV infection and the geographic distribution of NPC. METHODS: The serum levels of EBNA1-IgA, EBNA1-IgG, VCA-p18-IgA, VCA-p18-IgG, Zta-IgA and Zta-IgG in 303 healthy Zhongshan natives and 92 provisional migrants were tested using ELISA, and presented by values of adjusted relative absorbance (ArA). The serum levels and positive rates of the six antibodies were compared between the two groups. RESULTS: The mean ArA values of both Zta-IgA and VCA-p18-IgA were significantly higher in Zhongshan natives than in provisional migrants (0.84+/-0.03 vs. 0.42+/-0.04, P <0.05; 0.96+/-0.05 vs. 0.40+/-0.05, P<0.05). In addition, the positive rates of Zta-IgA and VCA-p18-IgA in subjects aged of 30-49, or of 50 and above were significantly higher in Zhongshan natives than in provisional migrants (29.27% vs. 3.03% and 48.28% vs. 6.67% for Zta-IgA, P<0.05; 28.46% vs. 9.09% and 43.10% vs. 13.33% for VCA-p18-igA, P<0.05). CONCLUSION: Zhongshan natives are likely to have an elevation of serum IgA antibodies against EBV lytic antigens (Zta and VCA-p18), which represents reactivation of EBV latency infection and implies that Zhongshan natives may have higher risk to develop NPC than provisional migrants.

Assessing the risk of nasopharyngeal carcinoma on the basis of EBV antibody spectrum.

We have evaluated the performance of 3 new EBV ELISA for the diagnosis of nasopharyngeal carcinoma (NPC). The tests were specific for EBNA 1 IgA, EBNA 1 IgG and zta IgG, respectively. Their distinct antigenic specificity permits these assays to be used in concert in an approach that differentiates patients and apparently healthy subjects on the basis of their antibody spectrum. By so exploiting a distinguishing feature of NPC first described by Lloyd Olds and his group (Olds et al., Proc Nat Acad Sci 1966;56:1699-1704) [corrected] that the patients sustain high levels of a broad spectrum of serum EBV antibodies, this approach achieved a sensitivity of 92% and a specificity of 93%, surpassing the performance of each of these assays individually. The enhanced performance is especially useful in population screening. It was shown that relative risk of NPC sustained by apparently healthy subjects residing in a high incidence area for NPC in the Pearl River estuary in Southern China may vary according to EBV antibody spectrum. The risk of the cancer was markedly reduced with odds ratios of 0.009 for 59% of those who had low level of all 3 antibodies. The risk was increased as antibody spectrum broadens and the risk was the highest with an odds ratio of 138 for 0.4% of those who had high levels of all 3 antibodies. Thus, EBV antibody spectrum may serve to guide follow-up measures for early detection of the cancer and/or risk counseling according to level of the risk of the cancer sustained by the screened individuals.