Technical note: Understanding the effect of COVID-19 on particle pollution using a low-cost sensor network.

The 2020 coronavirus pandemic and the following quarantine measures have led to significant changes in daily life worldwide. Preliminary research indicates that air quality has improved in many urban areas as a result of these measures. This study takes a neighborhood-scale approach to quantifying this change in pollution. Using data from a network of citizen-hosted, low-cost particulate matter (PM) sensors, called Air Quality & yoU (AQ&U), we obtained high-spatial resolution measurements compared to the relatively sparse state monitoring stations. We compared monthly average estimated PM2.5 concentrations from February 11 to May 11, 2019 at 71 unique locations in Salt Lake County, UT, USA with the same (71) sensors' measurements during the same timeframe in 2020. A paired t-test showed significant reductions (71.1% and 21.3%) in estimated monthly PM2.5 concentrations from 2019 to 2020 for the periods from March 11-April 10 and April 11-May 10, respectively. The March time period corresponded to the most stringent COVID-19 related restrictions in this region. Significant decreases in PM2.5 were also reported by state monitoring sites during March (p < 0.001 compared to the previous 5-year average). While we observed decreases in PM2.5 concentrations across the valley in 2020, it is important to note that the PM2.5 concentrations did not improve equally in all locations. We observed the greatest reductions at lower elevation, more urbanized areas, likely because of the already low levels of PM2.5 at the higher elevation, more residential areas, which were generally below 2 µg/m3 in both 2019 and 2020. Although many of measurements during March and April were near or below the estimated detection limit of the low-cost PM sensors and the federal equivalent measurements, every low-cost sensor (51) showed a reduction in PM2.5 concentration in March of 2020 compared to 2019. These results suggest that the air quality improvement seen after March 11, 2020 is due to quarantine measures reducing traffic and decreasing pollutant emissions in the region.

Characterization of renewable diesel particulate matter gathered from non-premixed and partially premixed flame burners and from a diesel engine.

Particulate matter coming from the combustion of renewable diesel (RD), ultra-low sulfur diesel (ULSD) and a volumetric blend of 30% of RD with ULSD (RD30) were collected and physico-chemically characterized. Soot samples were generated in two flame burner types (non-premixed flame, NPF, and partially premixed flame, PPF) trying to simulate the diffusion and premix regimes found in diesel engines. The impact of both fuel nature and burner type was assessed on soot mass, particle size and morphology, particle nanostructure and surface functional groups. In general, although the results of HRTEM and SMPS suggested that the addition of RD reduced the average particle size and increased the concentration of ultra-fine particles, the mass emission of soot was drastically mitigated regardless of the burner used. The results also suggest that the changes in the chemical characteristics of the soot were slightly more sensitive than the changes in the internal nanostructure of the particles, since the graphitic character (as showed by Raman and infrared analysis) increased as the RD content increased, being stronger for the PPF system. Comparisons between engine soot and flame soot confirmed that the addition of RD into ULSD produced smaller and more carbonized particles. In fact, some engine results were located in between those obtained in PPF and NPF burners, suggesting that both combustion regimes are contributing to soot characteristics in engines. This consistency suggests that a first assessment of the impact of alternative fuels on the characteristics of particulate matter can be conducted through the basic approach offered by laboratory flames, thereby avoiding the costs associated with generating large quantities of fuel and the complexities of in-cylinder physical interactions and engine parameters.

Long-term field evaluation of the Plantower PMS low-cost particulate matter sensors.

The low-cost and compact size of light-scattering-based particulate matter (PM) sensors provide an opportunity for improved spatiotemporally resolved PM measurements. However, these inexpensive sensors have limitations and need to be characterized under realistic conditions. This study evaluated two Plantower PMS (particulate matter sensor) 1003s and two PMS 5003s outdoors in Salt Lake City, Utah over 320 days (1/2016-2/2016 and 12/2016-10/2017) through multiple seasons and a variety of elevated PM2.5 events including wintertime cold-air pools (CAPs), fireworks, and wildfires. The PMS 1003/5003 sensors generally tracked PM2.5 concentrations compared to co-located reference air monitors (one tapered element oscillating microbalance, TEOM, and one gravimetric federal reference method, FRM). The different PMS sensor models and sets of the same sensor model exhibited some intra-sensor variability. During winter 2017, the two PMS 1003s consistently overestimated PM2.5 by a factor of 1.89 (TEOM PM2.5<40 µg/m3). However, compared to the TEOM, one PMS 5003 overestimated PM2.5 concentrations by a factor of 1.47 while the other roughly agreed with the TEOM. The PMS sensor response also differed by season. In two consecutive winters, the PMS PM2.5 measurements correlated with the hourly TEOM measurements (R2 > 0.87) and 24-h FRM measurements (R2 > 0.88) while in spring (March-June) and wildfire season (June-October) 2017, the correlations were poorer (R2 of 0.18-0.32 and 0.48-0.72, respectively). The PMS 1003s maintained high intra-sensor agreement after one year of deployment during the winter seasons, however, one PMS 1003 sensor exhibited a significant drift beginning in March 2017 and continued to deteriorate through the end of the study. Overall, this study demonstrated good correlations between the PMS sensors and reference monitors in the winter season, seasonal differences in sensor performance, some intra-sensor variability, and drift in one sensor. These types of factors should be considered when using measurements from a network of low-cost PM sensors.

Development of a calibration chamber to evaluate the performance of low-cost particulate matter sensors.

Low-cost particulate matter (PM) air quality sensors are becoming widely available and are being increasingly deployed in ambient and home/workplace environments due to their low cost, compactness, and ability to provide more highly resolved spatiotemporal PM concentrations. However, the PM data from these sensors are often of questionable quality, and the sensors need to be characterized individually for the environmental conditions under which they will be making measurements. In this study, we designed and assessed a cost-effective (∼$700) calibration chamber capable of continuously providing a uniform PM concentration simultaneously to multiple low-cost PM sensors and robust calibration relationships that are independent of sensor position. The chamber was designed and evaluated with a Computational Fluid Dynamics (CFD) model and a rigorous experimental protocol. We then used this new chamber to calibrate 242 Plantower PMS 3003 sensors from two production lots (Batches I and II) with two aerosol types: ammonium nitrate (for Batches I and II) and alumina oxide (for Batch I). Our CFD models and experiments demonstrated that the chamber is capable of providing uniform PM concentration to 8 PM sensors at once within 6% error and with excellent reliability (intraclass correlation coefficient > 0.771). The study identified two malfunctioning sensors and showed that the remaining sensors had high linear correlations with a DustTrak monitor that was calibrated for each aerosol type (R2 > 0.978). Finally, the results revealed statistically significant differences between the responses of Batches I and II sensors to the same aerosol (P-value<0.001) and the Batch I sensors to the two different aerosol types (P-value<0.001). This chamber design and evaluation protocol can provide a useful tool for those interested in systematic laboratory characterization of low-cost PM sensors.

Ambient and laboratory evaluation of a low-cost particulate matter sensor.

Low-cost, light-scattering-based particulate matter (PM) sensors are becoming more widely available and are being increasingly deployed in ambient and indoor environments because of their low cost and ability to provide high spatial and temporal resolution PM information. Researchers have begun to evaluate some of these sensors under laboratory and environmental conditions. In this study, a low-cost, particulate matter sensor (Plantower PMS 1003/3003) used by a community air-quality network is evaluated in a controlled wind-tunnel environment and in the ambient environment during several winter-time, cold-pool events that are associated with high ambient levels of PM. In the wind-tunnel, the PMS sensor performance is compared to two research-grade, light-scattering instruments, and in the ambient tests, the sensor performance is compared to two federal equivalent (one tapered element oscillating microbalance and one beta attenuation monitor) and gravimetric federal reference methods (FEMs/FRMs) as well as one research-grade instrument (GRIMM). The PMS sensor response correlates well with research-grade instruments in the wind-tunnel tests, and its response is linear over the concentration range tested (200-850 µg/m3). In the ambient tests, this PM sensor correlates better with gravimetric methods than previous studies with correlation coefficients of 0.88. However additional measurements under a variety of ambient conditions are needed. Although the PMS sensor correlated as well as the research-grade instrument to the FRM/FEMs in ambient conditions, its response varies with particle properties to a much greater degree than the research-grade instrument. In addition, the PMS sensors overestimate ambient PM concentrations and begin to exhibit a non-linear response when PM2.5 concentrations exceed 40 µg/m3. These results have important implications for communicating results from low-cost sensor networks, and they highlight the importance of using an appropriate correction factor for the target environmental conditions if the user wants to compare the results to FEM/FRMs.

T-cell and major histocompatibility complex requirements for obliterative airway disease in heterotopically transplanted murine tracheas.

BACKGROUND: One third of human lung allografts develop chronic rejection manifested as obliterative bronchiolitis. Heterotopically transplanted allogeneic murine tracheas develop obliterative airway disease (OAD) leading to a lesion resembling human obliterative bronchiolitis. The purpose of this study was to determine the T-cell and major histocompatibility complex (MHC) molecule requirements of murine OAD. METHODS: BALB/c allografts and C57BL/6 (B6) isografts were transplanted into B6 severe combined immunodeficient (SCID) and B6 wild-type (WT) recipients. MHC class I-discrepant bm1 grafts, class II-discrepant bm12 grafts, and F1(bm1 x bm12) (F1) grafts also were transplanted into B6 WT recipients. Grafts were harvested between days 5 and 56 following transplantation and evaluated histologically. RESULTS: Complete MHC-disparate allografts placed in WT recipients had significantly more disease than similar allografts in SCID recipients, and the latter were indistinguishable from isografts in either WT or SCID recipients, indicating a lymphocyte dependence on the disease development. Pathology was significantly more severe in bm1 and F1 allografts than in isografts recovered from B6 recipients, but bm12 allografts appeared no different than isografts. T-cell infiltrates in these bm12 allografts contained only CD4+ cells, whereas infiltrates in the BALB/c, bm1, and F1 allografts manifesting OAD contained both CD4+ and CD8+ cells. No grafts had significant B-cell infiltration. CONCLUSIONS: These findings suggest that OAD relies on a host T-cell response that includes CD8+ cells, directed against allo-class I-bearing donor cells within the graft.

Inhibition of thrombin by hirudin genetically fused to wild-type or mutant antithrombin.

Recombinant fusion proteins consisting of hirudin variant 3 (HV3) fused at its C-terminus to either of two forms of mature rabbit antithrombin (AT) were generated in COS-I cells. HV3 fused to wild-type AT was designated HAT, while a similar chimeric protein in which the P12 residue of AT was mutated from Ala to Thr, was designated HAT(H) for the Hamilton (A382T) mutation. Addition of the HV3 domain resulted in a decreased mobility of both HAT and HAT(H) relative to COS-derived AT (68 kDa versus 60 kDa). Both proteins had a greatly increased ability to inhibit thrombin in amidolytic activity assays, relative to recombinant AT. Addition of heparin to these reactions was without effect. Incubation of conditioned media containing recombinant AT with 125I-labelled thrombin resulted in the formation of SDS-stable AT-IIa complexes; no such complexes were detected in identical reactions containing either HV3-AT fusion protein. The two proteins did not differ significantly in their ability to compete for the binding of 125I-labelled thrombin to immobilized HV1 (CGP 39393). Both proteins were found to bind to heparin-Sepharose, but less tightly than unfused AT. This property was demonstrated by the peak elution of the fusion proteins at 0.65 M NaCl, as compared to that of COS-derived AT at 1.05 M NaCl. We conclude that the fusion proteins inhibit thrombin with similar affinity to unfused hirudin via their hirudin and not their antithrombin domains. The heparin-binding capability of these proteins may indicate the acquisition of vessel wall binding capacity by these novel forms of recombinant hirudin.

Type A behavior in employed women: relation to work, marital, and leisure variables, social support, stress, tension, and health.

Ninety-one women employed full-time were administered the Jenkins Activity Survey (JAS; Jenkins, Rosenman, & Zyzanski; 1974) and the Framingham Type A Scale (FTAS; Haynes, Levine, Scotch, Feinleib, & Kennel, 1978). Information concerning various work and nonwork-related variables was obtained via questionnaire or interview. Type A women had higher occupational levels and reported more demanding jobs and higher stress and tension than Type B women. Type A and B women did not differ in their reports of marital adjustment or in total hours spent in leisure activities. Type A behavior was related to both self-reported stress and tension--and for married women only, poorer self-reported physical health. Social support from various sources was not found to be related to Type A or Type B. Curiously, Type A was related to more reported stress and tension for women who felt they had many sources of support but not for women who did not perceive their having many sources of support.

Type A behavior in housewives: relation to work, marital adjustment, stress, tension, health, fear-of-failure and self esteem.

Ninety-five housewives were administered the Framingham Type A Scale and the Jenkins Activity Survey. Information concerning various aspects of their daily lives as well as various psychological and psychosocial variables were obtained via questionnaire and interview. Type As were found to differ from Type Bs in having more stressful work-related experiences. Further, Type As reported poorer marital adjustment and tended to report more marital disharmony than did Type Bs. Type A behavior was also related to more self-reported stress, tension, and physical health problems. Finally, Type As reported lower covert self-esteem and tended to report more fear-of-failure than Type Bs.

Pharyngoesophageal reconstruction using the radial forearm fasciocutaneous free flap: preliminary results.

Pharyngoesophageal reconstruction remains a challenge to the head and neck surgeon. The goals of pharyngoesophageal reconstruction include restoration, with minimal morbidity, of a person's ability to swallow and to speak. Myocutaneous flaps, gastric pull-up, and the jejunal free flap are popular methods of pharyngoesophageal reconstruction; however, none of these modalities is clearly ideal. We have begun utilizing the radial forearm fasciocutaneous free flap for pharyngoesophageal reconstruction. Twelve patients have had reconstruction with this flap with follow-up from 2 to 15 months. Seven defects were circumferential, and five were noncircumferential. Ten patients (83%) have had successful restoration of both swallowing ability and voice. Donor site morbidity was minimal. The leading complication was salivary leak, which was present in eight (67%) patients. Five of the leaks closed with nonsurgical intervention. No cases of flap necrosis occurred. The radial forearm free flap is a thin and pliable flap that closely approximates the tissue consistency of normal pharynx. Successful restoration of a patient's ability to swallow approximates that of enteral flaps and is superior to that of MC flaps. Successful speech restoration is superior to that of enteral and MC flaps. Donor site morbidity is less than that caused by enteral flaps because laparotomy is avoided. Salivary leak is higher than with enteral flaps. Part of this difference is accountable to the high number of secondary and technically challenging reconstructions in this series, and we have taken steps to lower this rate of leakage. These preliminary data show that the radial forearm fasciocutaneous free flap is well suited for pharyngoesophageal reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical glove perforations in otolaryngology: prevention with cut-resistant gloves.

This study examines the role of cut-resistant, "orthopedic-type" gloves in prevention of exposure of surgical personnel to infectious body fluids through surgical glove perforation. The incidence of glove perforations in 12 consecutive cases of intermaxillary fixation (IMF) was studied. Surgeons were double-gloved with standard latex gloves and wore cut-resistant gloves between the outer and inner gloves. As controls, six cadaver heads were wired into IMF with surgeons double-gloving without the cut-resistant glove. The rates of latex glove perforation were then compared between the two groups. Fifty-three percent (32 of 60) of outer latex gloves, but no inner latex gloves (0 of 50) were perforated when surgeons wore cut-resistant gloves. In the control group, 45% of outer gloves (9 of 20) and 15% of inner gloves (3 of 20) were perforated. The difference of inner glove perforations--hence cutaneous exposure--between these two groups was statistically significant (p < 0.01). The use of cut-resistant gloves in addition to double-gloving with latex surgical gloves is recommended for facial plastic and reconstructive procedures with metal implants and major head and neck surgery, because these operations have a high rate of glove perforation. Because some loss of dexterity is noted when cut-resistant gloves are worn, the risk of glove perforation must be weighted against the need for optimal dexterity.

An animal model of chronic tympanic membrane perforation.

Previous investigations into the healing and reconstruction of tympanic membrane (TM) perforations have involved animal models with acute TM perforations. A problem with the acute TM perforation model is that most acute TM perforations will heal spontaneously, both in animals and human beings. A second inadequacy of acute perforation models is that they are not analogous to the salient problem in human beings: long-standing TM perforation. The ideal animal model must have a TM perforation that is permanent, well-epithelialized, and free from infection. The perforation must also be subtotal to preserve a rim of membrane for experimental manipulations. In the chinchilla, we have identified a hardy animal with a short, wide ear canal and relatively large tympanic membranes. Thermal myringectomy, followed by medial infolding of TM microflaps, has resulted in permanent, subtotal chronic TM perforations in the chinchilla animal model. Of the 19 chinchillas (38 TMs) perforated, chronic subtotal perforations were created in 32 ears, 6 to 8 weeks after the initial procedure (84% success). Persistent infection or TM regeneration despite reperforation was recorded in 6 ears (16%) failure). This model is currently being used to assess various biomembrane scaffolds impregnated with growth-promoting substances in the regeneration of a physiologically sound TM, initially in our animal model and then in human beings. We envision the development of a biomembrane disc impregnated with biorecombinant growth factors that may provide a simple office technique for the repair of chronic, non-infected TM perforations.

Impact of parental anxiety on child emotional adjustment when a parent has cancer.

PURPOSE/OBJECTIVES: To describe the relationships among parent anxiety, child anxiety, and emotional adjustment in children who have a parent with cancer. DESIGN: Correlational. SETTING: A large cancer center in the southeastern United States. SAMPLE: Thirty-three child/parent with cancer dyads. METHODS: Research packets were mailed to child/parent dyads who agreed to participate in the study. Parents completed a demographic questionnaire, a Spielberger State-Trait Anxiety Scale, and a Personality Inventory for Children (PIC). Children completed the child version of the Spielberger State-Trait Anxiety Scale. MAIN RESEARCH VARIABLES: Parent anxiety, child anxiety, and child adjustment. FINDINGS: Children who have a parent with cancer and parents who have experienced cancer report significantly higher state and trait anxiety compared to a normed population sample. Parental reports on the PIC indicated that latency-aged children (i.e., 6-12 years) showed significantly greater internalization and somatic symptoms compared to the sample norm. Parent state anxiety was negatively correlated with children's internalization and somatic symptoms. Parental anxiety accounted for the greatest variance in child adjustment. IMPLICATIONS FOR NURSING PRACTICE: These study findings may provide nurses with a better understanding of the vulnerability of children who have a parent with cancer and can build a foundation for the development of supportive interventions for these children.

The external auditory canal. Anatomy and physiology.

Although the external auditory canal is relatively simple compared with other portions of the ear, the anatomy and physiology of the EAC are well adapted to permit efficient function under environmental extremes. This article contains a discussion of the embryology, anatomy, and physiology of the EAC. The most common disease of the EAC, cerumen impaction, is also considered. A thorough understanding of the normal EAC is essential for a study of its pathophysiology.

Audit review: requirement or significant help?

Although subject to modifications by political, funding and popular considerations, the audit review is seen as a useful step in quality care.

Toward distinguishing woodsmoke and diesel exhaust in ambient particulate matter.

Particulate matter (PM) from biomass burning and diesel exhaust has distinct X-ray spectroscopic, carbon specific signatures, which can be employed for source apportionment. Characterization of the functional groups of a wide selection of PM samples (woodsmoke, diesel soot, urban air PM) was carried out using the soft X-ray spectroscopy capabilities at the synchrotron radiation sources in Berkeley (ALS) and Brookhaven (NSLS). The spectra reveal that diesel exhaust particulate (DEP) matter is made up from a semigraphitic solid core and soluble organic matter, predominantly with carboxylic functional groups. Woodsmoke PM has no or a less prevalent, graphitic signature, instead it contains carbon-hydroxyl groups. Using these features to apportion the carbonaceous PM in ambient samples we estimate that the relative contribution of DEP to ambient PM in an urban area such as Lexington, KY and St. Louis, MO is 7% and 13.5%, respectively. These values are comparable to dispersion modeling data from nonurban and urban areas in California, and with elemental carbon measurements in urban locations such as Boston, MA, Rochester, NY, and Washington, DC.