An Improved Random Access Scheme for M2M Communications

In this study, an improved random access(RA) scheme for Machine-to-Machine(M2M) communications is proposed. The improved RA scheme is realized by two steps. First, the improved RA scheme achieves a reasonable resource tradeoff between physical random access channel(PRACH) and physical uplink shared channel(PUSCH). To realize a low-complexity resource allocation between PRACH and PUSCH, a boundary of traffic load is derived to divide the number of active M2 M users(UEs) into multiple intervals. The corresponding resource allocation for these intervals is determined by e NB. Then the resource allocation for other number of UEs can be obtained from the allocation of these intervals with less computation. Second, the access barring on arrival rate of new UEs is introduced in the improved RA scheme to reduce the expected delay. Numerical results show that the proposed improved RA scheme can realize a low-complexity resource allocation between PRACH and PUSCH. Meanwhile, the expected delay can be effectively reduced by access barring on arriving rate of new M2 M UEs.

Random Access and Resource Allocation for the Coexistence of NOMA-Based and OMA-Based M2M Communications

In the future fifth generation(5G) systems,non-orthogonal multiple access(NOMA) is a promising technology that can greatly enhance the network capacity compared to orthogonal multiple access(OMA) .In this paper,we propose a novel random access(RA) and resource allocation scheme for the coexistence of NOMA-based and OMAbased machine-to-machine(M2M) communications,which aims at improving the number of successful data packet transmissions and guaranteeing the quality of service(Qo S) (e.g.,the minimum data rate requirement) for M2 M communications.The algorithm of joint user equipment(UE) paring and power allocation is proposed for the coexisting RA(i.e.,the coexistence of NOMA-based RA and OMA-based RA) .The resource allocation for the coexisting RA is investigated,thus improving the number of successful data packet transmissions by more efficiently using the radio resources.Simulation results demonstrate that the proposed RA and resource allocation scheme outperforms the conventional RA in terms of the number of successful data packet transmissions,thus is a promising technology in future M2 M communications.

Identification and molecular cloning of novel antimicrobial peptides from skin secretions of the Chinese bamboo leaf odorous frog (Odorrana versabilis) and the North American pickerel frog (Rana palustris)

Objective:Amphibian skin secretions are an abundant source of bioactive peptides,some of which could be developed as candidate drugs.Among these natural peptides,cytolytic peptides have attracted the most attention given that they might replace conventional antibiotics and help deal with the problem of microbial resistance.This study discovered two bioactive peptides,Brevinin-1-PLr and Nigrocin-2-OV,from two species frogs,the Chinese bamboo leaf odorous frog (Odorrana versabilis) and the North American pickerel frog (Rana palustris),respectively.Their antimicrobial,anticancer and hemolytic activities were also investigated.Methods:cDNA sequences encoding peptides were cloned from cDNA libraries constructed from the lyophilized secretions of the Chinese bamboo leaf odorous frog and the North American pickerel frog.By reversed-phase HPLC and MS/MS fragmentation sequencing,the encoded novel peptides,named Nigrocin-2-OV and Brevinin-1-PLr,were identified in skin secretions and their structures were confirmed.Replicates of both peptides were produced through solid phase peptide synthesis.Their antimicrobial and anticancer activity was studied against three types of microorganisms (Staphylococcus aureus,Candida albicans,and Escherichia coli) and five cancer cell lines (NCI-H157,PC-3,MDA-MB-435s,MCF-7,and U251MG).Their hemolytic activity was investigated using whole horse blood.Results:In this research,cDNA sequences encoding two novel 24-mer peptides were cloned from cDNA libraries constructed from the lyophilized skin secretions of the Chinese bamboo leaf odorous frog and the North American pickerel frog.Both of the peptides had the strongest inhibitory effect against C.albicans,and IC50 values against five cancer cell lines were all under 6 μM.Conclusions:Nigrocin-2-OV and Brevinin-1-PLr had the strong ability to inhibit the proliferation of studied microorganisms and tumor cell lines,with slight hemolytic activity.Compared with Brevinin-1-PLr,Nigrocin-2-OV exhibited higher antimicrobial and anticancer activity but slightly higher hemolytic activity.

The Planar Ramsey Numbers PR (K₄-e, K_l)

The planar Ramsey number PR (H1, H2) is the smallest integer n such that any planar graph on n vertices contains a copy of H1 or its complement contains a copy of H2. It is known that the Ramsey number R(K4 -e, K6) = 21, and the planar Ramsey numbers PR(K4 - e, Kl) for l ≤ 5 are known. In this paper, we give the lower bounds on PR (K4 ? e, Kl) and determine the exact value of PR (K4 - e, K6).

A study of the initial adhesive force of cells on silk fibroin-based materials using micropipette aspiration

With the development of biomaterials,more attention is paid to the adhesion characteristics between cells and materials.It is necessary to study the adhesive force with a suitable method.Silk fibroin(SF)is widely investigated in biomedical application due to its novel biocompatibility and mechanical properties.In this article,the micropipette aspiration method and measurement pattern of uniform cells in round shape(UCR)was used to study the initial adhesive force of three types of cells on pure silk fibroin films(SFFs).We also compared the adhesive forces of modified SFFs with that of pure SFFs.The results of adhesive force in the initial adhesive stage were in concordance with the results of MTT assay andmicroscope observation,which were confirmed by the above three cell lines and four kinds of SFFs.The results indicated UCR was an efficient and quantitative measurement pattern in initial adhesion stage.This article also provides a useful method in identifying initial cell-materials interactions.

夫妻共同感染梅毒螺旋体临床表型及实验室指标差异

目的探讨夫妻共同感染梅毒螺旋体后临床表型及实验室指标差异。方法收集2015年3月至2021年7月于首都医科大学附属北京地坛医院首次诊治且人类免疫缺陷病毒(HIV)阴性的共同感染梅毒螺旋体夫妻32对。根据我国2020年梅毒和神经梅毒最新诊断标准分为症状神经梅毒(NS)-无症状NS夫妻组17对,NS-隐性梅毒夫妻组15对。分别比较两组患者夫妻间年龄、性别、外周血淋巴细胞计数和比值、梅毒血清学指标、脑脊液(CSF)白细胞(WBC)计数、蛋白(Pro)定量和葡萄糖(Glu)浓度、CSF梅毒相关指标等差异,通过条件Logistic回归分析影响夫妻间临床表型差异的因素。结果在症状NS-无症状NS夫妻组中,无症状NS患者T淋巴细胞计数较症状NS患者高(t=-2.184、P=0.047),无症状NS患者CD4^(+)T(t=-2.088、P=0.056)和CD8^(+)T(t=-2.112、P=0.053)淋巴细胞计数高于症状NS患者,但差异无统计学意义;症状NS患者CSF TRUST滴度(Z=-2.124、P=0.034)和CSF Pro定量(Z=-3.006、P=0.003)高于无症状NS患者;条件Logistic回归分析显示,男性患者更易表现为症状NS(OR=14.000、95%CI:1.841~106.465、P=0.011)。NS-隐性梅毒夫妻组中,NS患者淋巴细胞(t=2.322、P=0.040)、T淋巴细胞(t=2.385、P=0.036)和CD8^(+)T淋巴细胞计数(t=2.801、P=0.017),CSF Pro定量(Z=-2.062、P=0.039)及血清TRUST滴度(Z=-3.000、P=0.003)均显著高于隐性梅毒患者;条件Logistic回归分析显示CD8^(+)T淋巴细胞计数高的患者更易表现为NS,但差异无统计学意义(OR=1.008、95%CI:0.998~1.018、P=0.130)。结论当夫妻双方共患NS时,男性表现为症状NS的风险高于女性,夫妻间T淋巴细胞计数,血清和CSF TRUST滴度,CSF Pro等实验室指标差异可能与机体的免疫应答和炎症反应有关。