Social network strategy as a promising intervention to better reach key populations for promoting HIV prevention: a systematic review and meta-analysis.

INTRODUCTION: Key populations such as men who have sex with men (MSM), drug users and sex workers are at high risk of HIV infection, but they are marginalised and hidden. Social network strategy (SNS) is purposeful to use social networks to generate social influence, accelerate behaviour change and achieve desirable outcomes among individuals or communities and have been increasingly used for HIV interventions. This study aims to investigate the effects of SNS on HIV prevention among key populations. METHODS: We searched six databases, including PubMed, Web of Science, Embase, Cochrane Library, ScienceDirect and Wiley for randomised controlled trials published between January 1999 and May 2019. Eligibility criteria included SNS conducted among key populations for HIV interventions, with a comparator group. Outcomes included changes in HIV high-risk behaviour, HIV seroconversion and other HIV outcomes. We used the risk ratio (RR) or mean difference with associated 95% confidence interval (CI) to assess the comparative efficacy between SNS and control methods on the selected outcomes. The GRADE system was used to assess the quality of evidence for the studies. RESULTS: Of 2818 citations identified, 28 trails from 24 papers met the inclusion criteria. The results showed that SNS was associated with less unprotected intercourse (RR 0.79, 95% CI 0.72 to 0.86) and sex with multiple partners (0.46, 95% CI 0.33 to 0.65). Additionally, relative to the control methods, SNS significantly reduced HIV seroconversion (0.65, 95% CI 0.53 to 0.81), improved HIV testing uptake (1.11, 95% CI 1.07 to 1.15) and promoted participant retention (1.03, 95% CI 1.00 to 1.06) among key populations. The Grading of Recommendations Assessment, Development and Evaluation system showed that trails were of moderate quality. CONCLUSIONS: This review provides evidence that SNS can reach key populations who are currently not being reached by existing programmes and deliver HIV interventions through social networks, which decreases HIV sexual risk behaviour and HIV incidence and increases HIV testing uptake and participant retention. TRIAL REGISTRATION NUMBER: CRD42019140533.

Study on Microstructure and Properties of Black Micro-Arc Oxidation Coating on AZ31 Magnesium Alloy by Orthogonal Experiment.

The effects of CuSO4 concentration, voltage and treating time on the hemisphere emissivity and corrosion resistance of AZ31B magnesium-alloy black micro-arc oxidation coatings were studied by orthogonal experiment. The microstructure, phase composition, corrosion resistance and hemisphere emissivity of the coating were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical test and infrared emissivity spectrometer, respectively. The results showed that the influences of each factor on corrosion current density and the hemisphere emissivity are as follows: voltage > treating time > CuSO4 concentration. The black MAO coatings are mainly composed of WO3, MgAl2O4, CuAl2O4, MgO, CuO and MgF2. The CuO and CuAl2O4 phases are the main reasons for blackness of the coatings. The coating exhibits the best corrosion resistance under the conditions of CuSO4 concentration 1.5 g/L, oxidation voltage 500 V and treating time 10 min. Additionally, the variation trends of hemispherical emissivity and roughness of the black MAO coating are the same when the composition of the coatings is similar. When the concentration of CuSO4 is 1.5 g/L, the oxidation voltage is 450 V and the treatment time is 10 min, the coating with the highest hemispherical emissivity of 0.84 can be obtained.

Effect of (NH4)2ZrF6, Voltage and Treating Time on Corrosion Resistance of Micro-Arc Oxidation Coatings Applied on ZK61M Magnesium Alloys.

The effects of (NH4)2ZrF6 concentration, voltage and treating time on the corrosion resistance of ZK61M magnesium alloy micro-arc oxidation coatings were studied by orthogonal experiments. The SEM result shows that the surface roughness and porosity of MAO coatings increased with (NH4)2ZrF6 concentration, voltage and treating time as a whole, except the porosity decreased with treating time. EDS, XRD and XPS analysis show that (NH4)2ZrF6 was successfully incorporated into coatings by reactive incorporation, coatings are dominantly composed of ZrO2, MgO, MgF2 and amorphous phase Mg phosphate. Potentiodynamic polarization was used to evaluate the corrosion property of coatings. When the concentration of (NH4)2ZrF6 is 6 g/L, the voltage is 450 V, and the treating time is 15 min, the coating exhibits the best corrosion resistance which corrosion current density is four magnitudes lower than substrate attributed to the incorporation of ZrO2 and the deposition of MgF2 in the micropores.

Repetitive Transcranial Magnetic Stimulation Alleviates Neurological Deficits After Cerebral Ischemia Through Interaction Between RACK1 and BDNF exon IV by the Phosphorylation-Dependent Factor MeCP2.

Repetitive transcranial magnetic stimulation (rTMS) is acknowledged as a form of neurostimulation, especially for functional recovery. The foundational knowledge of molecular mechanism is limited regarding its role in cerebral ischemia, for which the present study was designed. Primary neurons were treated with oxygen-glucose deprivation (OGD) and repetitive magnetic stimulation (rMS), in which brain-derived neurotrophic factor (BDNF) and transcription of BDNF exons were examined. Then, adenovirus vectors carrying siRACK1 sequence were delivered to primary neurons, followed by detection of the transcription of BDNF exons and the extent of methyl CpG binding protein 2 (MeCP2) phosphorylation. Results showed that BDNF and the transcription of BDNF exons were upregulated by rMS and OGD treatment, but decreased by extra treatment of RACK1 siRNA. Then, the mechanism investigations demonstrated that rMS increased the extent of MeCP2 phosphorylation to promote the interaction between RACK1 and BDNF exon IV. The aforementioned findings were further confirmed in vivo in middle cerebral artery occlusion (MCAO)-induced rat models, as indicated by improved neurological functions and reduced area of cerebral infarction. The study offers potential evidence for improvement of neurological deficits, highlighting the important role of rTMS for treatment of cerebral ischemia.

Morphology and Wear Resistance of Composite Coatings Formed on a TA2 Substrate Using Hot-Dip Aluminising and Micro-Arc Oxidation Technologies.

Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium coatings and ceramic layers were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase structure of the MAO layers was studied using X-ray diffraction. The surface composition of the MAO layer was studied by X-ray photoelectron spectroscopy. The wear resistance of the pure titanium substrate and the ceramic layers coated on its surface were evaluated by using the ball-on-disc wear method. Therefore, aluminising coatings, which consist of a diffusion layer and a pure aluminium layer, could be formed on pure titanium substrates using the hot-dip aluminising method. The MAO method enabled the in-situ oxidation of hot-dip pure aluminium layers, which subsequently led to the formation of ceramic layers. Moreover, the wear resistance values of the ceramic layers were significantly higher than that of the pure titanium substrate.

Effect of Diffusion Annealing Temperature on the Formation Process and Properties of a Carbon-Aluminum Composite Layer on Pure Titanium.

A carbon-aluminum composite layer was prepared on the surface of pure titanium by double glow plasma carburizing, magnetron sputtering aluminizing, and vacuum-diffusional annealing treatment. The microstructure, phase composition, and properties of the composite layer obtained at different annealing temperatures were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and the ball-on-disc wear method. Results showed that the layer contained a mixture of TiAl3, Ti2Al5, and TiC phases at 650 °C for 6 h, which can significantly enhance the hardness and wear resistance of pure titanium. The layer exhibited a higher hardness of around 1231 HV0.1, a lower friction coefficient of 0.33, and lower wear volumes of 0.018 mm3 than those of the titanium substrate.

ß-L-Arabinofuranosylation Conducted by 5-O-(2-pyridinecarbonyl)-L-arabinofuranosyl Trichloroacetimidate.

We describe a ß-L-arabinofuranosylation method by employing the 5-O-(2-pyridinecarbonyl)-L-arabinofuranosyl trichloroacetimidate 10 as a donor. This approach allows a wide range of acceptor substrates, especially amino acid acceptors, to be used. Stereoselective synthesis of ß-(1,4)-L-arabinofuranosyl-(2S, 4R)-4-hydroxy-L-proline (ß-L-Araf-L-Hyp4) and its dimer is achieved readily by this method. Both the stereoselectivities and yields of the reactions are excellent. To demonstrate the utility of this methodology, the preparation of a trisaccharide in a one-pot manner was carried out.

Tanshinone II A inhibits dendritic cell-mediated adaptive immunity: potential role in anti-atherosclerotic activity.

OBJECTIVE: Antigen-presenting cells such as monocytes and dendritic cells (DCs) stimulate T-cell proliferation and activation during adaptive immunity. This cellular interaction plays a role in the growth of atherosclerotic plaques. Tanshinone II A (TSN) had been shown to decrease the growth of atherosclerotic lesions. We therefore investigated the ability of TSN to inhibit human monocyte-derived DCs and their T-cellstimulatory capacity. METHODS: DCs derived from human monocytes cultured with recombinant human interleukin (IL)-4 and recombinant human granulocyte-macrophage colony-stimulating factor were co-cultured with TSN and lipopolysaccharide for 48 h. Phosphate-buffered saline was used as a negative control. Activation markers and the capacity of DCs for endocytosis were measured by flow cytometry, and proinflammatory cytokines were measured by enzyme-linked immunosorbent assays. DCs were co-cultured with lymphocytes to measure T-cell proliferation and IL-2 secretion by mixed lymphocyte reactions. RESULTS: TSN dose-dependently attenuated DC expression of costimulatory molecules (CD86), and decreased expression of major histocompatibility complex class II (human loukocyte antigen-DR) and adhesion molecules (CD54). Moreover, TSN reduced secretion of the proinflammatory cytokines IL-12 and IL-1 by human DCs, and restored the capacity for endocytosis. Finally, TSN-preincubated DCs showed a reduced capacity to stimulate T-cell proliferation and cytokine secretion. CONCLUSIONS: TSN inhibits DC maturation and decreases the expression of proinflammatory cytokines, while impairing their capacity to stimulate T-cell proliferation and cytokine secretion. These effects may contribute to the influence of TSN on the progression of atherosclerotic lesions.

[Morphological characteristics of internal carotid artery atherosclerotic lesions in digital subtracted angiography].

OBJECTIVE: To illustrate the morphological characteristics of atherosclerotic lesions of the internal carotid artery. METHODS: The morphological characteristics of cervicocerebral atherosclerotic lesions in digital subtracted angiography were retrospectively reviewed in 120 cases. RESULTS: Totally 217 atherosclerotic lesions were detected. Of all the lesions, moderately and severely stenosed lesions accounted for 62.21% and mild stenosed lesions for 37.79%; long lesions were found in 18.89% and short ones in 81.11%; 37.33% of the lesions were ulcerated while 62.67% were non-ulcerated; 13.36% were angulated lesions and 86.64% non-angulated; 50.23% were eccentric lesions and 49.77% were concentric; lesions with adjacent artery dilation were found in 9.22%, and lesions without with adjacent artery dilation in 90.78%. CONCLUSION: The atherosclerotic lesions are characterized by moderate to severe stenosis and non-ulcerated, non-angulated, eccentric lesions without adjacent artery dilation.