In this paper, the inhomogeneous structure of generalized seismic strain release time series (GSSRTS) of earth- quakes in East, West China and their subtectonic regions as Xinjiang, Qinghai-Xizang (Tibetan) Plateau, N...In this paper, the inhomogeneous structure of generalized seismic strain release time series (GSSRTS) of earth- quakes in East, West China and their subtectonic regions as Xinjiang, Qinghai-Xizang (Tibetan) Plateau, Northeast China, North China, South China and Taiwan have been analyzed by using the method of significant analysis on zero crossings of derivatives (SiZer). Results show that when index η for estimating GSSRTS is close to zero and bandwidth is large enough, GSSRTSs feature significant increasing in Xinjiang, Northeast China, South China and Taiwan tectonic regions and decreasing in Qinghai-Xizang (Tibetan Platean) and North China tectonic regions from January 1, 1970 to January 1, 2000. While with the dwindling of bandwidth GSSRTSs in all the above tec- tonic regions characterize clustering, that is to say, significant increasing and decreasing emerge alternatively. When η is large enough, GSSRTSs would have no significant statistical variation in most of above tectonic regions except Qinghai-Xizang (Tibetan Platean) and Taiwan where significant increasing or decreasing hold in several time intervals within limited bandwidths.展开更多
Low-cost sensors are widely used to collect high-spatial-resolution particulate matter data that traditional reference monitoring devices cannot.In addition to the mass concentration,the number concentration and size ...Low-cost sensors are widely used to collect high-spatial-resolution particulate matter data that traditional reference monitoring devices cannot.In addition to the mass concentration,the number concentration and size distribution are also fundamental in determining the origin and hazard level of particulate pollution.Therefore,low-cost optical sensors have been improved to establish optical particle sizers(OPSs).In this study,a low-cost OPS,the Nova SDS029,is introduced,and it is evaluated in comparison to two reference instruments—the GRIMM 11-D and the TSI 3330.We first tested the sizing accuracy using polystyrene latex spheres.Then,we assessed the mass and number size distribution accuracy in three application scenarios:indoor smoking,ambient air quality,and mobile monitoring.The evaluations suggest that the low-cost SDS029 rivals research-grade optical sizers in many aspects.For example,(1)the particle diameters obtained with the SDS029 are close to the reference instruments(usually<10%)in the 0.3-5μm range;(2)the number of particles and mass concentration are highly correlated(r≥0.99)with the values obtained with the reference instruments;and(3)the SDS029 slightly underestimates the number concentration,but the derived PM_(2.5)values are closer to monitoring station than the reference instruments.The successful application of the SDS029 in multiple scenarios suggests that a plausible particle size distribution can be obtained in an easy and cost-efficient way.We believe that low-cost OPSs will increasingly be used to map the sources and risk levels of particles at the city scale.展开更多
Laser particle sizers (LPS’s) measure the size of smallparticles from the phenomenon of light scattering, whilescattering by large particles is considered to consists ofdiffraction. Mie’s Theory applies to small par...Laser particle sizers (LPS’s) measure the size of smallparticles from the phenomenon of light scattering, whilescattering by large particles is considered to consists ofdiffraction. Mie’s Theory applies to small particles down tosubmicron dimensions. OMEC recognizes that the scat-tering theory should be used for both large and small par-ticles in order to have a precise description of the scat-展开更多
BACKGROUND Transmission of severe acute respiratory syndrome coronavirus 2 can occur during aerosol generating procedures.Several steps in spinal fusion may aerosolize blood but little data exists to quantify the risk...BACKGROUND Transmission of severe acute respiratory syndrome coronavirus 2 can occur during aerosol generating procedures.Several steps in spinal fusion may aerosolize blood but little data exists to quantify the risk this may confer upon surgeons.Aerosolized particles containing infectious coronavirus are typically 0.5-8.0μm.AIM To measure the generation of aerosols during spinal fusion using a handheld optical particle sizer(OPS).METHODS We quantified airborne particle counts during five posterior spinal instrumentation and fusions(9/22/2020-10/15/2020)using an OPS near the surgical field.Data were analyzed by 3 particle size groups:0.3-0.5μm/m^(3),1.0-5.0μm/m^(3),and 10.0μm/m^(3).We used hierarchical logistic regression to model the odds of a spike in aerosolized particle counts based on the step in progress.A spike was defined as a>3 standard deviation increase from average baseline levels.RESULTS Upon univariate analysis,bovie(P<0.0001),high speed pneumatic burring(P=0.009),and ultrasonic bone scalpel(P=0.002)were associated with increased 0.3-0.5μm/m^(3)particle counts relative to baseline.Bovie(P<0.0001)and burring(P<0.0001)were also associated with increased 1-5μm/m^(3)and 10μm/m^(3)particle counts.Pedicle drilling was not associated with increased particle counts in any of the size ranges measured.Our logistic regression model demonstrated that bovie(OR=10.2,P<0.001),burring(OR=10.9,P<0.001),and bone scalpel(OR=5.9,P<0.001)had higher odds of a spike in 0.3-0.5μm/m^(3)particle counts.Bovie(OR=2.6,P<0.001),burring(OR=5.8,P<0.001),and bone scalpel(OR=4.3,P=0.005)had higher odds of a spike in 1-5μm/m^(3)particle counts.Bovie(OR=0.3,P<0.001)and drilling(OR=0.2,P=0.011)had significantly lower odds of a spike in 10μm/m^(3)particle counts relative to baseline.CONCLUSION Several steps in spinal fusion are associated with increased airborne particle counts in the aerosol size range.Further research is warranted to determine if such particles have the potential to contain infectious viruses.Previous research has shown that electrocautery smoke may be an inhalation hazard for surgeons but here we show that usage of the bone scalpel and high-speed burr also have the potential to aerosolize blood.展开更多
基金Natural Science Foundation of Shandong Province (Y2002E01), Key Project for Earthquake Prevention and Disaster Mitigation in Shandong (SD10503-02-05) and Project of China-Greece International Cooperation of Science and Technology from 2003 to 2005.
文摘In this paper, the inhomogeneous structure of generalized seismic strain release time series (GSSRTS) of earth- quakes in East, West China and their subtectonic regions as Xinjiang, Qinghai-Xizang (Tibetan) Plateau, Northeast China, North China, South China and Taiwan have been analyzed by using the method of significant analysis on zero crossings of derivatives (SiZer). Results show that when index η for estimating GSSRTS is close to zero and bandwidth is large enough, GSSRTSs feature significant increasing in Xinjiang, Northeast China, South China and Taiwan tectonic regions and decreasing in Qinghai-Xizang (Tibetan Platean) and North China tectonic regions from January 1, 1970 to January 1, 2000. While with the dwindling of bandwidth GSSRTSs in all the above tec- tonic regions characterize clustering, that is to say, significant increasing and decreasing emerge alternatively. When η is large enough, GSSRTSs would have no significant statistical variation in most of above tectonic regions except Qinghai-Xizang (Tibetan Platean) and Taiwan where significant increasing or decreasing hold in several time intervals within limited bandwidths.
基金supported by the National Natural Science Foundation of China(No.42075182)。
文摘Low-cost sensors are widely used to collect high-spatial-resolution particulate matter data that traditional reference monitoring devices cannot.In addition to the mass concentration,the number concentration and size distribution are also fundamental in determining the origin and hazard level of particulate pollution.Therefore,low-cost optical sensors have been improved to establish optical particle sizers(OPSs).In this study,a low-cost OPS,the Nova SDS029,is introduced,and it is evaluated in comparison to two reference instruments—the GRIMM 11-D and the TSI 3330.We first tested the sizing accuracy using polystyrene latex spheres.Then,we assessed the mass and number size distribution accuracy in three application scenarios:indoor smoking,ambient air quality,and mobile monitoring.The evaluations suggest that the low-cost SDS029 rivals research-grade optical sizers in many aspects.For example,(1)the particle diameters obtained with the SDS029 are close to the reference instruments(usually<10%)in the 0.3-5μm range;(2)the number of particles and mass concentration are highly correlated(r≥0.99)with the values obtained with the reference instruments;and(3)the SDS029 slightly underestimates the number concentration,but the derived PM_(2.5)values are closer to monitoring station than the reference instruments.The successful application of the SDS029 in multiple scenarios suggests that a plausible particle size distribution can be obtained in an easy and cost-efficient way.We believe that low-cost OPSs will increasingly be used to map the sources and risk levels of particles at the city scale.
文摘Laser particle sizers (LPS’s) measure the size of smallparticles from the phenomenon of light scattering, whilescattering by large particles is considered to consists ofdiffraction. Mie’s Theory applies to small particles down tosubmicron dimensions. OMEC recognizes that the scat-tering theory should be used for both large and small par-ticles in order to have a precise description of the scat-
文摘BACKGROUND Transmission of severe acute respiratory syndrome coronavirus 2 can occur during aerosol generating procedures.Several steps in spinal fusion may aerosolize blood but little data exists to quantify the risk this may confer upon surgeons.Aerosolized particles containing infectious coronavirus are typically 0.5-8.0μm.AIM To measure the generation of aerosols during spinal fusion using a handheld optical particle sizer(OPS).METHODS We quantified airborne particle counts during five posterior spinal instrumentation and fusions(9/22/2020-10/15/2020)using an OPS near the surgical field.Data were analyzed by 3 particle size groups:0.3-0.5μm/m^(3),1.0-5.0μm/m^(3),and 10.0μm/m^(3).We used hierarchical logistic regression to model the odds of a spike in aerosolized particle counts based on the step in progress.A spike was defined as a>3 standard deviation increase from average baseline levels.RESULTS Upon univariate analysis,bovie(P<0.0001),high speed pneumatic burring(P=0.009),and ultrasonic bone scalpel(P=0.002)were associated with increased 0.3-0.5μm/m^(3)particle counts relative to baseline.Bovie(P<0.0001)and burring(P<0.0001)were also associated with increased 1-5μm/m^(3)and 10μm/m^(3)particle counts.Pedicle drilling was not associated with increased particle counts in any of the size ranges measured.Our logistic regression model demonstrated that bovie(OR=10.2,P<0.001),burring(OR=10.9,P<0.001),and bone scalpel(OR=5.9,P<0.001)had higher odds of a spike in 0.3-0.5μm/m^(3)particle counts.Bovie(OR=2.6,P<0.001),burring(OR=5.8,P<0.001),and bone scalpel(OR=4.3,P=0.005)had higher odds of a spike in 1-5μm/m^(3)particle counts.Bovie(OR=0.3,P<0.001)and drilling(OR=0.2,P=0.011)had significantly lower odds of a spike in 10μm/m^(3)particle counts relative to baseline.CONCLUSION Several steps in spinal fusion are associated with increased airborne particle counts in the aerosol size range.Further research is warranted to determine if such particles have the potential to contain infectious viruses.Previous research has shown that electrocautery smoke may be an inhalation hazard for surgeons but here we show that usage of the bone scalpel and high-speed burr also have the potential to aerosolize blood.
