The Novel Spectrum Allocation Algorithm in Cognitive Radio System

In order to reduce the disturbance on an authorizing user and lower the competition between cognitive users, assure the normal communication of a cognitive radio system, reliability theory is applied to describe if a channel can be used by a cognitive user or not and the probability that the channel is continually used for a period. Three aspects including space, time domain and frequency domain are united for the research on the distribution of frequency spectrum. The simulation result shows that, in the space domain, time domain, frequency domain algorithm, the transmitted data volume and the total throughput of the system are superior to those in greedy algorithm and time domain—frequency domain algorithm, the novel algorithm is helpful to reduce the disturbance caused by a cognitive user to an authorizing user and lower the competition between cognitive users, this simulation result shows that the proposed algorithm is effective.

Redox-neutral C–H acylation of indole with ketene by manganese catalysis

A low-cost manganese-catalyzed oxidant-free selective C–H acylation of indole with ketene is reported.This protocol features mild reaction conditions and good functional group tolerance.The yield is from middle to excellent.The acylation products can be further converted to diverse useful compounds.Mechanism study reveals the acylation transformation possibly undergoes a cyclomanganated complex species as reactive intermediate.

Zoonotic and antibiotic-resistant Campylobacter:a view through the One Health lens

As a pathogen of a major public health concern with animal health importance,Campylobacter constitutes a clear and present threat to One Health.This organism colonizes the intestinal tract and is widely distributed among various animal species,including livestock and poultry,companion animals,and wildlife.As a result of its broad distribu-tion,Campylobacter is exposed to antibiotics used in both human and veterinary medicine,which creates antibiotic selection pressure that has driven the development and rising prevalence of antibiotic resistant Campylobacter.This is particularly evident with the resistance to fluoroquinolone(FQ),which has become a great concern for public health.However,the increased prevalence of antibiotic-resistant Campylobacter cannot be solely attributed to antibiotic usage,as interspecies transmission and subsequent clonal expansion also contribute to the dissemination of antibiotic-resistant Campylobacter.This is exemplified by the emergence and expansion of FQ-resistant Campylo-bacter clones in animal production systems where FQ antibiotics were never used,the transmission of extensively drug resistant Campylobacter from dogs to human patients,and the spread of antibiotic-resistant and hypervirulent Campylobacter from ruminants to humans.Another notable finding from recently published work is the emergence of antibiotic resistance genes of Gram-positive origin in Campylobacter,suggesting that genetic exchange between Campylobacter and Gram-positive bacteria occurs in the natural environment and is more frequent than previously realized.Once these“foreign”antibiotic resistance genes are presented in Campylobacter,they can further disseminate by clonal expansion or horizontal gene transfer among different Campylobacter species/strains.These findings indi-cate that the emergence and transmission of antibiotic-resistant Campylobacter in the ecosystem are complex and multidirectional,and are affected by multiple factors.Thus,a holistic and One Health approach is necessary to fully comprehend and mitigate antibiotic resistant Campylobacter.