Optoelectronic oscillator for 5G wireless networks and beyond

With the development of 5G wireless network and beyond, the wireless carrier frequency will definitely reach millimeter-wave (mm-wave) and even terahertz (THz). As one of the key elements in wireless networks, the local oscillator (LO) needs to operate at mm-wave and THz band with lower phase noise, which becomes a major challenge for commercial LOs. In this article, we investigate the recent developments of the electronic integrated circuit (EIC) oscillator and the optoelectronic oscillator (OEO), and especially investigate the prospect of OEO serving as a qualified LO in the 5G wireless network and beyond. Both the EIC oscillators and OEOs are investigated, including their basic theories of operation, representative techniques and some milestones in applications. Then, we compare the performances between the EIC oscillators and the OEOs in terms of frequency accuracy, phase noise, power consumption and cost. After describing the specific requirements of LO based on the standard of 5G and 6G wireless communication systems, we introduce an injection-locked OEO architecture which can be implemented to distribute and synchronize LOs. The OEO has better phase noise performance at high frequency, which is greatly desired for LO in 5G wireless network and beyond. Besides, the OEO provides an easy and low-loss method to distribute and synchronize mm-wave and THz LOs. Thanks to photonic integrated circuit development, the power consumption and cost of OEO reduce gradually. It is foreseeable that the integrated OEO with lower cost may have a promising prospect in the 5G wireless network and beyond

Barriers to hospital and tuberculosis programme collaboration in China: context matters

Background: In many developing countries, programmes for ‘diseases of social importance’, such as tuberculosis (TB), have traditionally been organised as vertical services. In most of China, general hospitals are required to report and refer suspected TB cases to the TB programme for standardised diagnosis and treatment. General hospitals are the major contacts of health services for the TB patients. Despite the implementation of public–public/private mix, directly observed treatment, short-course, TB reporting and referral still remain a challenge. Objective: This study aims to identify barriers to the collaboration between the TB programme and general hospitals in China. Design: This is a qualitative study conducted in two purposefully selected counties in China: one in Zhejiang, a more affluent eastern province, and another in Guangxi, a poorer southwest province. Sixteen in-depth interviews were conducted and triangulated with document review and field notes. An open systems perspective, which views organisations as social systems, was adopted. Results: The most perceived problem appeared to be untimely reporting and referral associated with non-standardised prescriptions and hospitalisation by the general hospitals. These problems could be due to the financial incentives of the general hospitals, poor supervision from the TB programme to general hospitals, and lack of technical support from the TB programme to the general hospitals. However, contextual factors, such as different funding natures of different organisations, the prevalent medical and relationship cultures, and limited TB funding, could constrain the processes of collaboration between the TB programme and the general hospitals. Conclusions: The challenges in the TB programme and general hospital collaboration are rooted in the context. Improving collaboration should reduce the potential mistrust of the two organisations by aligning their interests, improving training, and improving supervision of TB control in the hospitals. In particular, effective regulatory mechanisms are crucial to alleviate the negative impact of the contextual factors and ensure smooth collaboration

Faba Bean (Vicia faba L.) Nodulating Rhizobia in Panxi, China, Are Diverse at Species, Plant Growth Promoting Ability, and Symbiosis Related Gene Levels

We isolated 65 rhizobial strains from faba bean (Vicia faba L.) from Panxi, China, studied their plant growth promoting ability with nitrogen free hydroponics, genetic diversity with clustered analysis of combined ARDRA and IGS-RFLP, and phylogeny by sequence analyses of 16S rRNA gene, three housekeeping genes and symbiosis related genes. Eleven strains improved the plant shoot dry mass significantly comparing to that of not inoculated plants. According to the clustered analysis of combined ARDRA and IGS-RFLP the isolates were genetically diverse. Forty-one of 65 isolates represented Rhizobium anhuiense, and the others belonged to R. fabae, Rhizobium vallis, Rhizobium sophorae, Agrobacterium radiobacter, and four species related to Rhizobium and Agrobacterium. The isolates carried four and five genotypes of nifH and nodC, respectively, in six different nifH-nodC combinations. When looking at the species-nifH-nodC combinations it is noteworthy that all but two of the six R. anhuiense isolates were different. Our results suggested that faba bean rhizobia in Panxi are diverse at species, plant growth promoting ability and symbiosis related gene levels.Peer reviewe

Doping Fe-based diamond tool matrix composites with a rare-earth element

The paper presents the experiments on adding rare-earth element cerium to diamond matrix composites. Based on the doping of rare earth in metal powders including tungsten carbide, a small amount of nickel, iron entirely replacing cobalt in diamond matrix and the process route of rare earth doping is indicated. The performance of matrix composites with and without rare-earth elements has been assessed. The results obtained show that the flexural strength, the hardness, and the impact ductility of matrix composites with rare-earth elements have been improved. The flexural strength and the impact ductility increased correspondently by 10—62 % and about 5 %, as compared to composites free of rare-earth elements. Rare-earth diamond tool matrix composites where Co was replaced with Fe, which provides a good practical service performanc, and a low price, have been successfully studied, corresponding diamond bits and saw blades have been manufactured

In vitro Protective Effect of Ganoderol A Isolated from Ganadermalucidum Against Ultraviolet A Radiation and its Anti-inflammatory Properties

Purpose: To evaluate the ultraviolet A (UVA) protection and anti-inflammatory activity of ganoderol A extracted from Ganodermalucidum.Methods: The cytotoxicity and in vitro protective effect of ganoderol A against UVA damage were evaluated by MTT assay. Apoptosis and cell-cycle arrest of NIH/3T3 fibroblast cells were assayed by fluorescence-activated cell sorting (FCS). Expression of monocyte chemotactic protein-1 (MCP-1) and inducible nitric oxide synthase (iNOS) were determined using quantitative real-time polymerase chain reaction (qPCR).Results: The results indicate that the maximal non-toxic concentration of ganoderol A in NIH/3T3 cells and RAW 264.7 macrophages was 50 and 25 μg/mL respectively. DNA in the tails and tail length decreased by 55 and 70 %, respectively, in the group pretreated with ganoderol A compared with the UVA-treated group. G1 phase cells decreased by 23 %, whereas the number of apoptotic cells returned to normal. The expression of MCP-1 and iNOS declined to 60 and 15 %, respectively, compared with LPS-stimulated group.Conclusion: Ganoderol A has significant anti-inflammatory activity and protection against UVA damage, thus suggesting that the compound is a  candidate for the development of a suitable product to protect skin from UV-induced photoaging.Keywords: Anti-ultraviolet A, Anti-inflammatory, Ganoderol A, Ganodermalucidum, Photoagin

Características físico-químicas y antioxidantes del aceite de semillas de Neocarya macrophylla

This study examined the physicochemical characteristics and antioxidant activities of oils extracted from gingerbread plum kernels grown in two different areas (Niger and Guinea). The oil contents were found to be significantly different (P ≤ 0.05); 56% and 60% for gingerbread plum kernels originated from Niger (GPKN) and guinea (GPKG), respectively. GPKG showed the highest levels for physical parameters such as iodine, saponification, free fatty acid, acid and peroxide values when compared with GPKN. The major monounsaturated fatty acid in both GPKN and GPKG was oleic acid (42.46 and 41.43%, respectively) while the polyunsaturated fatty acids consisted of linoleic and arachidonic acid. Arachidonic acid was at higher levels (17.67 and 21.72% in GPKN and GPKG, respectively) than those in common vegetable oils. Results from antioxidant activity essays showed that GPKG is more active than GPKN in DPPH radical scavenging, β-carotene and phenolic contents while GPKN showed the highest values for reducing power and flavonoid. Of the 11 sterol compounds found in this study, 24-hydroxy-24-methyl cholesterol, clerosterol and sitosterol accounted for 68.5% and 66.33% in GPKN and GPKG, respectively. Finally, all tocopherol vitamers (except γ-tocopherol) were present in GPKN and GPKG with α-tocopherol being the main element in both samples.En este estudio se examinaron las características físico-químicas y actividad antioxidante de los aceites de semilla de Neocarya macrophylla procedentes de dos regiones distintas, Níger y Guinea. Los contenidos grasos de las dos semillas resultaron ser significativamente (P ≤ 0.05) diferentes: 56% para las semillas procedentes de Níger (GPKN) y 60% para las de Guinea (GPKG). El aceite de semillas de Guinea mostraba valores de parámetros químicos tales como índices de iodo, saponificación, peróxidos, y acidez, más elevados que el aceite de semillas de Níger. El ácido oleico resultó ser el ácido graso mono-insaturado más abundante en ambos casos (42.26% para el aceite de Níger y 41.42% para el de Guinea), mientras que los ácidos grasos poli-insaturados predominantes resultaron ser los ácidos linoleico y araquidódico. Los niveles de ácido araquidónico (17.68% para GPKN y 21.72% para GPKG) resultaron más elevados que los encontrados en otros aceites vegetales comunes. El aceite de GPKG demostró mayor capacidad de eliminación de radicales (ensayo de la difenil picrilhidrazina), así como mayores contenidos de β-caroteno y fenoles, mientras que el de GPKN mostró mayor poder reductor y contenido de flavonoides. De los 11 esteroles detectados, 24-hidroxi-24-metil colesterol, colesterol y sitosterol representaban el 68.5% y el 66.33% para los aceites de GPKN y GPKG respectivamente. Por último, todos los tocoferoles (excepto γ-tocoferol) estaban presentes en los dos aceites, siendo α-tocoferol el más abundante