Zobrazení zdroje stránky Lindbergstack9274

The excellent electrical properties of graphene provide a new functional finishing idea for fabricating conductive cotton fabrics with antistatic properties. This work develops a novel method for synthesizing active graphene to make cotton fabrics conductive and to have antistatic properties. The graphite was oxidized to graphene oxide (GO) by the Hummers method, and was further acid chlorinated and reacted with the para-ester to form the active graphene (JZGO). JZGO was then applied to cotton fabrics and was bonded to the fiber surface under alkaline conditions. Characterizations were done using FT-IR, XRD and Raman spectroscopy, which indicated that the para-ester group was successfully introduced onto JZGO, which also effectively improved the water dispersibility and reactivity of the JZGO. Furthermore, this study found that the antistatic properties of the fabric were increased by more than 50% when JZGO was 3% by weight under low-humidity conditions. The washing durability of the fabrics was also evaluated.Background Depending on the epidemiological context of each country, three vaccines are recommended by the World Health Organization (WHO) to be administered as soon as possible after birth (birth vaccines); namely, BCG, zero dose of oral polio vaccine (OPV0), and birth dose of hepatitis B vaccine (HepB-BD). The timely administration of these vaccines immediately after birth might pose significant challenges in sub-Saharan Africa, where about half of childbirths occur outside health facilities. We therefore conducted a systematic review and meta-analysis to estimate the coverage rate of these vaccines at a specific timing in neonates in sub-Saharan Africa. Methods We searched PubMed, Embase, CINAHL, and Web of Science for studies conducted in sub-Saharan Africa and published up to March 31, 2017, which provided a coverage rate of the birth vaccines at any specific time points within 28 days after birth. Two investigators independently screened the titles and abstracts and extracted data from the eligible full-text articles. This study was registered in PROSPERO (CRD42017071269). Results Of 7283 articles identified, we finally included 31 studies with 204,111 infants in the meta-analysis. The pooled coverage rates at day 0-1 after birth were 14.2% (95% CI 10.1-18.9) for BCG and 1.3% (0.0-4.5) for HepB-BD. No data were available for OPV0 at day 0-1. The coverage at day 28 was 71.7% (63.7-79.2) for BCG, 60.8% (45.8-74.7) for HepB-BD, and 76.1% (67.1-84.0) for OPV0. No significant difference in the vaccine coverage was observed between infants born in healthcare facilities and those born outside facilities. Conclusions The rates of vaccine coverage immediately after birth were very low for BCG and HepB-BD, and no data for OPV0. We need additional data to better define barriers and facilitators for the timely administration of the birth vaccines in sub-Saharan Africa, since the delay in its provision may increase the burden of these vaccine-preventable diseases.Tunicates (ascidians) are common marine invertebrates that are an exceptionally important source of natural products with biomedical and pharmaceutical applications, including compounds that are used clinically in cancers. Among tunicates, the genus Didemnum is important because it includes the most species, and it belongs to the most speciose family (Didemnidae). The genus Didemnum includes the species D. molle, D. [https://www.selleckchem.com/products/zotatifin.html Zotatifin ic50] chartaceum, D. albopunctatum, and D. obscurum, as well as others, which are well known for their chemically diverse secondary metabolites. To date, investigators have reported secondary metabolites, usually including bioactivity data, for at least 69 members of the genus Didemnum, leading to isolation of 212 compounds. Many of these compounds exhibit valuable biological activities in assays targeting cancers, bacteria, fungi, viruses, protozoans, and the central nervous system. This review highlights compounds isolated from genus Didemnum through December 2019. Chemical diversity, pharmacological activities, geographical locations, and applied chemical methods are described.In an effort to gain more understanding on the structure activity relationship of pseudoceratidine 1, a di-bromo pyrrole spermidine alkaloid derived from the marine sponge Pseudoceratina purpurea that has been shown to exhibit potent biofouling, anti-fungal, antibacterial, and anti-malarial activities, a large series of 65 compounds that incorporated several aspects of structural variation has been synthesised through an efficient, divergent method that allowed for a number of analogues to be generated from common precursors. Subsequently, all analogues were assessed for their antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Overall, several compounds exhibited comparable or better activity than that of pseudoceratidine 1, and it was found that this class of compounds is generally more effective against Gram-positive than Gram-negative bacteria. Furthermore, altering several structural features allowed for the establishment of a comprehensive structure activity relationship (SAR), where it was concluded that several structural features are critical for potent anti-bacterial activity, including di-halogenation (preferable bromine, but chlorine is also effective) on the pyrrole ring, two pyrrolic units in the structure and with one or more secondary amines in the chain adjoining these units, with longer chains giving rise to better activities.Photovoltaic (PV) power generation has been extensively used as a result of the limited petrochemical resources and the rise of environmental awareness. Nevertheless, PV arrays have a widespread range of voltage changes in a variety of solar radiation, load, and temperature circumstances, so a maximum power point tracking (MPPT) method must be applied to get maximum power from PV systems. Sliding mode control (SMC) is effectively used in PV power generation due to its robustness, design simplicity, and superior interference suppression. When the PV array is subject to large parameter changes/highly uncertain conditions, the SMC leads to degraded steady-state performance, poor transient tracking speed, and unwanted flutter. Therefore, this paper proposes a robust intelligent sliding mode MPPT-based high-performance pure sine wave inverter for PV applications. The robust SMC is designed through fast sliding regime, which provides fixed time convergence and a non-singularity that allows better response in steady-state and transience.