A Real-Time Contactless Pulse Rate and Motion Status Monitoring System Based on Complexion Tracking.

Subject movement and a dark environment will increase the difficulty of image-based contactless pulse rate detection. In this paper, we detected the subject's motion status based on complexion tracking and proposed a motion index (MI) to filter motion artifacts in order to increase pulse rate measurement accuracy. Additionally, we integrated the near infrared (NIR) LEDs with the adopted sensor and proposed an effective method to measure the pulse rate in a dark environment. To achieve real-time data processing, the proposed framework is constructed on a Field Programmable Gate Array (FPGA) platform. Next, the instant pulse rate and motion status are transmitted to a smartphone for remote monitoring. The experiment results showed the error of the pulse rate detection to be within -3.44 to +4.53 bpm under sufficient ambient light and -2.96 to + 4.24 bpm for night mode detection, when the moving speed is higher than 14.45 cm/s. These results demonstrate that the proposed method can improve the robustness of image-based contactless pulse rate detection despite subject movement and a dark environment.

Construction of 2,3-dihydrofuran cores through the [3+2] cycloaddition of gold alpha-carbonylcarbenoids with alkenes.

Treatment of 2-epoxy-1-alkynylbenzenes with electron-rich alkenes and a [AuCl(PR(3))]/AgX catalyst in CH(2)Cl(2) led to the formation of 2-alkenyl-1-(2,3-dihydrofuran-4-yl)benzenes. This transformation comprises of a gold-catalyzed redox reaction to form a gold alpha-carbonylcarbenoid initially, which then reacts in situ with an alkene in a [3+2] cycloaddition. A range of alkenes are amenable to this tandem reaction, amongst them alpha-substituted styrenes, enol ethers, and 2,3-dimethylbutadienes. Deuterium-labeling experiments suggest a stepwise mechanism for the alpha-carbonylcarbenoid/alkene [3+2] cycloaddition. The resulting 2,3-dihydrofuran products allow access to diverse oxacyclic compounds through a stereoselective ene-oxonium reaction initiated by treatment with HOTf (1 mol %; Tf=trifluoromethanesulfonyl). A stepwise pathway is proposed for this reaction. The feasibility for direct transformation of 2-alkenyl-1-alkynylbenzenes into the desired 2,3-dihydrofuran products through initial m-chloroperbenzoic acid oxidation, followed by the addition of gold catalyst and alkene, has also been demonstrated.

Enhancing the Efficiency of a Forward Osmosis Membrane with a Polydopamine/Graphene Oxide Layer Prepared Via the Modified Molecular Layer-by-Layer Method.

Water scarcity is one of the most critical problems that humans have to face. Working toward solving this problem, we have developed a thin-film composite (TFC) membrane using the modified molecular layer-by-layer (modified mLBL) method to fabricate polyamide (PA) active layers on different substrates. Besides, it has been found that graphene oxide (GO) contains abundant functional groups such as hydroxyl and epoxide groups, which are able to improve both the physical and chemical properties of the forward osmosis (FO) membrane. Thus, we have employed graphene oxide (GO) as the substrate and used the modified mLBL method to prepare active polydopamine/graphene oxide (PDA/GO) layers to enhance the water flux of the forward osmosis (FO) membrane. PDA/GO-coated layers could enhance the hydrophilic nature of the substrate and lower its surface roughness, which would facilitate the formation of the PA layer. Moreover, the PDA/GO coating can be applied to all substrates because of the high degree of adhesion of PDA to different substrates. In this study, the highly hydrophilic poly(vinylidene fluoride) membrane is superior in FO properties, with a water flux of 17.32 LMH and a reverse solute flux of 4.34 gMH. In addition, an excellent performance of 60.15 LMH and 14.88 gMH can be achieved when the pressure-retarded osmosis (PRO) test mode with a draw solution concentration of 2.0 M is used in the test. It shows that the membrane prepared using the novel method showed excellent FO performance, which has high potential in industrial applications such as desalination.

Polysaccharidic spent coffee grounds for silver nanoparticle immobilization as a green and highly efficient biocide.

Spent coffee grounds (SCGs) contain abundant polysaccharides and several components with bioactivities. Despite many bio-functionalities, their bioactivities are not always satisfactory. Modifications of SCGs may overcome this issue. This work describes the method for reusing the SCGs as biological macromolecular supports and reducing agents to prepare silver nanoparticle (AgNP)/SCGS composites (AgNPs@SCGs) by biogenic synthesis. The AgNPs anchored on the surface of SCGs were synthesized by mixing the SCGs in AgNO3 solution with various pH conditions at room temperature. Scanning electron microscopy (SEM) and X-ray diffractometer (XRD) analysis confirmed the reduction of silver ions to AgNPs, and showed that the pH 4.5 condition could generate uniform and impurity-free AgNPs on the surface of SCGs. Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and thermal gravimetric analysis (TGA) showed that the reducing process of AgNPs was mild and could preserve the original nature of the SCGs. The AgNPs@SCGs composites exhibited an excellent antimicrobial ability against S. aureus and E. coli compared to SCGs. The transformation of the polysaccharidic SCGs to AgNPs@SCGs composites by the green and sustainable method makes them highly valuable for developing the applications on antimicrobial products.

Gold-catalyzed hydrative carbocyclization of 1,5- and 1,7-allenynes mediated by pi-allene complex: mechanistic evidence supported by the chirality transfer of allenyne substrates.

We report PPh3AuCl/AgOTf-catalyzed hydrative carbocyclization of 1,5- and 1,7-allenynes to give cyclized ketones chemoselectively. In this transformation, hydration occurrs regioselectively at the C[triple bond]CPh carbon, accompanied by addition of the C[triple bond]CPh carbon to the two terminal allenyl carbons. This method is effective for the construction of a quaternary carbon center. On the basis of the chirality transfer of allenyne substrates, control experiments, and theoretic calculations, we propose that this hydrative carbocyclization proceeds through an initial pi-allene complex with a small energy barrier.

Pt- and Au-catalyzed oxidative cyclization of 2-ethenyl-1-(prop-2'-yn-1'-ol)benzenes to naphthyl aldehydes and ketones: catalytic oxidation of metal-alkylidene intermediates using H2O and H2O2.

2-Ethenyl-1-(prop-2'-yn-1'-ol)benzenes was cyclized through catalytic oxidation with PtCl(2)/CO/H(2)O and PEt(3)AuCl/H(2)O(2); the metal-naphthylidene intermediates were identified and oxygenated with water and H(2)O(2), respectively; for the efficiency of cyclization, the Au catalytic system is superior to that of the PtCl(2)-catalysis because of its compatibility toward diverse alcohol substrates including both internal alkynes and terminal alkynes.

Diversity in gold- and silver-catalyzed cycloisomerization of epoxide-alkyne functionalities.

We report Au(I)- and Ag(I)-catalyzed cycloisomerizations of epoxide-alkyne functionalities in both aromatic and nonaromatic systems, leading to diversified carbocyclic and heterocyclic frameworks with high chemoselectivities. The use of such cycloisomerizations is reflected by a facile access to the cores of natural pallidol and gibberic acid.

Gold-catalyzed synthesis of bicyclo[4.3.0]nonadiene derivatives via tandem 6-endo-dig/Nazarov cyclization of 1,6-allenynes.

Catalytic cyclization of 1,6-allenynes was achieved by AuPPh(3)SbF(6) (5 mol %) in cold CH(2)Cl(2) (0 degrees C, 0.5-4 h) to form bicyclo[4.3.0]nonadiene products; this cyclization proceeded more efficiently for a substrate bearing R = alkyl (yields >70%). We propose a reaction mechanism involving a 6-endo-dig cyclization of Au(I)-pi-alkyne, followed by Nazarov cyclization.