Development of an Integrated Disposable Device for SARSCoV-2 Nucleic Acid Extraction and Detection

Objective To develop a highly sensitive and rapid nucleic acid detection method for the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Methods We designed,developed,and manufactured an integrated disposable device for SARS-CoV-2 nucleic acid extraction and detection.The precision of the liquid transfer and temperature control was tested.A comparison between our device and a commercial kit for SARS-Cov-2 nucleic acid extraction was performed using real-time fluorescence reverse transcription polymerase chain reaction(RT-PCR).The entire process,from SARS-CoV-2 nucleic acid extraction to amplification,was evaluated.Results The precision of the syringe transfer volume was 19.2±1.9μL(set value was 20),32.2±1.6(set value was 30),and 57.2±3.5(set value was 60).Temperature control in the amplification tube was measured at 60.0±0.0℃(set value was 60)and 95.1±0.2℃(set value was 95)respectively.SARS-Cov-2 nucleic acid extraction yield through the device was 7.10×10^(6) copies/mL,while a commercial kit yielded 2.98×10^(6) copies/mL.The mean time to complete the entire assay,from SARS-CoV-2 nucleic acid extraction to amplification detection,was 36 min and 45 s.The detection limit for SARS-CoV-2 nucleic acid was 250 copies/mL.Conclusion The integrated disposable devices may be used for SARS-CoV-2 Point-of-Care test(POCT).

Catalytic hydrogenolysis of organosolv lignin: Cleaving C–O bonds over CuMgAlOx-layered porous metal oxide catalysts for oriented monophenols production

To understand the catalytic conversion of lignin into high-value products,lignin depolymerization was performed using a layered polymetallic oxide(CuMgAlOx)catalyst.The effects of the conversion temperature,hydrogen pressure,and reaction time were studied,and the ability of CuMgAlOx to break the C–O bond was evaluated.The CuMgAlOx(Mg/Al=3:1)catalyst contained acidic sites and had a relatively homogeneous elemental distribution with a high pore size and specific surface area.Theβ-O-4 was almost completely converted by disassociating the C–O bond,resulting in yields of 14.74%ethylbenzene,47.58%α-methylphenyl ethanol,and 36.43%phenol.The highest yield of lignin-derived monophenols was 85.16%under reaction conditions of 280°C and 3 Mpa for 4 h.As the reaction progressed,depolymerization and condensation reactions occurred simultaneously.Higher temperatures(>280℃)and pressures(>3 Mpa)tended to produce solid char.This study establishes guidelines for the high-value application of industrial lignin in the catalytic conversion of polymetallic oxides.

Crack evolution of soft–hard composite layered rock-like specimens with two fissures under uniaxial compression

Acoustic emission and digital image correlation were used to study the spatiotemporal evolution characteristics of crack extension of soft and hard composite laminated rock masses(SHCLRM)containing double fissures under uniaxial compression.The effects of different rock combination methods and prefabricated fissures with different orientations on mechanical properties and crack coalescence patterns were analyzed.The characteristics of the acoustic emission source location distribution,and frequency changes of the crack evolution process were also investigated.The test results show that the damage mode of SHCLRM is related to the combination mode of rock layers and the orientation of fractures.Hard layers predominantly produce tensile cracks;soft layers produce shear cracks.The first crack always sprouts at the tip or middle of prefabricated fractures in hard layers.The acoustic emission signal of SHCLRM with double fractures has clear stage characteristics,and the state of crack development can be inferred from this signal to provide early warning for rock fracture instability.This study can provide a reference for the assessment of the fracture development status between adjacent roadways in SHCLRM in underground mines,as well as in roadway layout and support.

Multi-peak spectrum of KML Ti:sapphire pulse

The multi-peak spectrum of Ti: sapphire pulses observed experimentally under ultra-broad bandwidth conditions ( 【 15 fs pulse length) has been explained theoretically. It is shown that the self-phase-modulation effect is equivalent to the process of degenerate four-wave frequency-mixing. Based on this theoretical underpinning, the presence or absence of a multipeak spectrum provides a practical measure of whether the intracavity group-velocity-dispersion is ideally compensated for or not.