Global population exposure to landscape fire air pollution from 2000 to 2019.

Wildfires are thought to be increasing in severity and frequency as a result of climate change1-5. Air pollution from landscape fires can negatively affect human health4-6, but human exposure to landscape fire-sourced (LFS) air pollution has not been well characterized at the global scale7-23. Here, we estimate global daily LFS outdoor fine particulate matter (PM2.5) and surface ozone concentrations at 0.25° × 0.25° resolution during the period 2000-2019 with the help of machine learning and chemical transport models. We found that overall population-weighted average LFS PM2.5 and ozone concentrations were 2.5 µg m-3 (6.1% of all-source PM2.5) and 3.2 µg m-3 (3.6% of all-source ozone), respectively, in 2010-2019, with a slight increase for PM2.5, but not for ozone, compared with 2000-2009. Central Africa, Southeast Asia, South America and Siberia experienced the highest LFS PM2.5 and ozone concentrations. The concentrations of LFS PM2.5 and ozone were about four times higher in low-income countries than in high-income countries. During the period 2010-2019, 2.18 billion people were exposed to at least 1 day of substantial LFS air pollution per year, with each person in the world having, on average, 9.9 days of exposure per year. These two metrics increased by 6.8% and 2.1%, respectively, compared with 2000-2009. Overall, we find that the global population is increasingly exposed to LFS air pollution, with socioeconomic disparities.

Nociceptors are functionally male or female: from mouse to monkey to man.

The prevalence of many pain conditions often differs between sexes. In addition to such quantitative distinctions, sexual dimorphism may also be qualitative reflecting differences in mechanisms that promote pain in men and women. A major factor that influences the likelihood of pain perception is the threshold for activation of nociceptors. Peripheral nociceptor sensitization has been demonstrated to be clinically relevant in many pain conditions. Whether peripheral nociceptor sensitization can occur in a sexually dimorphic fashion, however, has not been extensively studied. To address this fundamental knowledge gap, we used patch clamp electrophysiology to evaluate the excitability of dorsal root ganglion neurones from male or female rodents, non-human primates, and humans following exposure to putative sensitizing agents. Previous studies from our laboratory, and others, have shown that prolactin promotes female-selective pain responses in rodents. Consistent with these observations, dorsal root ganglion neurones from female, but not male, mice were selectively sensitized by exposure to prolactin. The sensitizing action of prolactin was also confirmed in dorsal root ganglion neurones from a female macaque monkey. Critically, neurones recovered from female, but not male, human donors were also selectively sensitized by prolactin. In the course of studies of sleep and pain, we unexpectedly observed that an orexin antagonist could normalize pain responses in male animals. We found that orexin B produced sensitization of male, but not female, mouse, macaque, and human dorsal root ganglion neurones. Consistent with functional responses, increased prolactin receptor and orexin receptor 2 expression was observed in female and male mouse dorsal root ganglia, respectively. Immunohistochemical interrogation of cultured human sensory neurones and whole dorsal root ganglia also suggested increased prolactin receptor expression in females and orexin receptor 2 expression in males. These data reveal a functional double dissociation of nociceptor sensitization by sex, which is conserved across species and is likely directly relevant to human pain conditions. To our knowledge, this is the first demonstration of functional sexual dimorphism in human sensory neurones. Patient sex is currently not a common consideration for the choice of pain therapy. Precision medicine, based on patient sex could improve therapeutic outcomes by selectively targeting mechanisms promoting pain in women or men. Additional implications of these findings are that the design of clinical trials for pain therapies should consider the proportions of male or female patients enrolled. Lastly, re-examination of selected past failed clinical trials with subgroup analysis by sex may be warranted.

Multi-node wearable optical sensor based on microfiber Bragg gratings.

Flexibly wearable sensors are widely applied in health monitoring and personalized therapy. Multiple-node sensing is essential for mastering the health condition holistically. In this work, we report a multi-node wearable optical sensor (MNWOS) based on the cascade of microfiber Bragg gratings (µFBG), which features the reflective operation mode and ultra-compact size, facilitating the functional integration in a flexible substrate pad. The MNWOS can realize multipoint monitoring on physical variables, such as temperature and pressure, in both static and dynamic modes. Furthermore, the eccentric package configuration endows the MNWOS with the discernibility of bending direction in addition to the bending angle sensing. The multi-parameter sensing is realized by solving the sensing matrix that represents different sensitivity regarding the bending and temperature between FBGs. The MNWOS offers great prospect for the development of human-machine interfaces and medical and health detection.

Continued Rise in Health Burden from Ambient PM2.5 in India under SSP Scenarios Until 2100 despite Decreasing Concentrations.

Forecasting alterations in ambient air pollution and the consequent health implications is crucial for safeguarding public health, advancing environmental sustainability, informing economic decision making, and promoting appropriate policy and regulatory action. However, predicting such changes poses a substantial challenge, requiring accurate data, sophisticated modeling methodologies, and a meticulous evaluation of multiple drivers. In this study, we calculate premature deaths due to ambient fine particulate matter (PM2.5) exposure in India from the 2020s (2016-2020) to the 2100s (2095-2100) under four different socioeconomic and climate scenarios (SSPs) based on four CMIP6 models. PM2.5 concentrations decreased in all SSP scenarios except for SSP3-7.0, with the lowest concentration observed in SSP1-2.6. The results indicate an upward trend in the five-year average number of deaths across all scenarios, ranging from 1.01 million in the 2020s to 4.12-5.44 million in the 2100s. Further analysis revealed that the benefits of reducing PM2.5 concentrations under all scenarios are largely mitigated by population aging and growth. These findings underscore the importance of proactive measures and an integrated approach in India to improve atmospheric quality and reduce vulnerability to aging under changing climate conditions.

Chronic pain recruits hypothalamic dynorphin/kappa opioid receptor signalling to promote wakefulness and vigilance.

Increased vigilance in settings of potential threats or in states of vulnerability related to pain is important for survival. Pain disrupts sleep and conversely, sleep disruption enhances pain, but the underlying mechanisms remain unknown. Chronic pain engages brain stress circuits and increases secretion of dynorphin, an endogenous ligand of the kappa opioid receptor (KOR). We therefore hypothesized that hypothalamic dynorphin/KOR signalling may be a previously unknown mechanism that is recruited in pathological conditions requiring increased vigilance. We investigated the role of KOR in wakefulness, non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep in freely moving naïve mice and in mice with neuropathic pain induced by partial sciatic nerve ligation using EEG/EMG recordings. Systemic continuous administration of U69,593, a KOR agonist, over 5 days through an osmotic minipump decreased the amount of NREM and REM sleep and increased sleep fragmentation in naïve mice throughout the light-dark sleep cycle. We used KORcre mice to selectively express a Gi-coupled designer receptor activated by designer drugs (Gi-DREADD) in KORcre neurons of the hypothalamic paraventricular nucleus, a key node of the hypothalamic-pituitary-adrenal stress response. Sustained activation of Gi-DREADD with clozapine-N-oxide delivered in drinking water over 4 days, disrupted sleep in these mice in a similar way as systemic U69,593. Mice with chronic neuropathic pain also showed disrupted NREM and total sleep that was normalized by systemic administration of two structurally different KOR antagonists, norbinaltorphimine and NMRA-140, currently in phase II clinical development, or by CRISPR/Cas9 editing of paraventricular nucleus KOR, consistent with endogenous KOR activation disrupting sleep in chronic pain. Unexpectedly, REM sleep was diminished by either systemic KOR antagonist or by CRISPR/Cas9 editing of paraventricular nucleus KOR in sham-operated mice. Our findings reveal previously unknown physiological and pathophysiological roles of dynorphin/KOR in eliciting arousal. Physiologically, dynorphin/KOR signalling affects transitions between sleep stages that promote REM sleep. Furthermore, while KOR antagonists do not promote somnolence in the absence of pain, they normalized disrupted sleep in chronic pain, revealing a pathophysiological role of KOR signalling that is selectively recruited to promote vigilance, increasing chances of survival. Notably, while this mechanism is likely beneficial in the short-term, disruption of the homeostatic need for sleep over longer periods may become maladaptive resulting in sustained pain chronicity. A novel approach for treatment of chronic pain may thus result from normalization of chronic pain-related sleep disruption by KOR antagonism.

Near-infrared microfiber Bragg grating for sensitive measurement of tension and bending.

Fiber-optic devices working in the visible and near-infrared windows are attracting attention due to the rapid development of biomedicine that involves optics. In this work, we have successfully realized the fabrication of near-infrared microfiber Bragg grating (NIR-µFBG), which was operated at the wavelength of 785 nm, by harnessing the fourth harmonic order of Bragg resonance. The NIR-µFBG provided the maximum sensitivity of axial tension and bending to 211 nm/N and 0.18 nm/deg, respectively. By conferring the considerably lower cross-sensitivity, such as response to temperature or ambient refractive index, the NIR-µFBG can be potentially implemented as the highly sensitive tensile force and curve sensor.

Association between ambient carbon monoxide levels and hospitalization costs of patients with myocardial infarction: Potential effect modification by ABO blood group.

Previous researches have reported the association between air pollution and various diseases. However, few researches have investigated whether air pollutants are associated with the economic loss resulting from patients' hospitalization, especially the economic loss of hospitalization due to acute cardiovascular events. The purpose of our research was to explore the association between the levels of carbon monoxide (CO), taken as an index of pollution, and the hospitalization costs of myocardial infarction (MI), and the potential effect modification by the ABO blood group. A total of 3237 MI inpatients were included in this study. A multiple linear regression model was used to evaluate the association between ambient CO levels and hospitalization costs of MI patients. Moreover, we performed stratified analyses by age, gender, body mass index (BMI), season, hypertension, and ABO blood types. There was a positive association between the levels of CO in the air and the costs of hospitalization caused by MI. Furthermore, such association was stronger in males, BMI ≥25, <65 years, with hypertension, and non-O blood group. Interestingly, we found the association was particularly significant in patients with blood group B. Overall, our study first found that ambient CO levels could have an impact on the hospitalization costs for MI patients, and those with blood group B can be more sensitive.

Exposure to wildfire-related PM2.5 and site-specific cancer mortality in Brazil from 2010 to 2016: A retrospective study.

BACKGROUND: Long-term exposure to fine particles ≤2.5 µm in diameter (PM2.5) has been linked to cancer mortality. However, the effect of wildfire-related PM2.5 exposure on cancer mortality risk is unknown. This study evaluates the association between wildfire-related PM2.5 and site-specific cancer mortality in Brazil, from 2010 to 2016. METHODS AND FINDINGS: Nationwide cancer death records were collected during 2010-2016 from the Brazilian Mortality Information System. Death records were linked with municipal-level wildfire- and non-wildfire-related PM2.5 concentrations, at a resolution of 2.0° latitude by 2.5° longitude. We applied a variant difference-in-differences approach with quasi-Poisson regression, adjusting for seasonal temperature and gross domestic product (GDP) per capita. Relative risks (RRs) and 95% confidence intervals (CIs) for the exposure for specific cancer sites were estimated. Attributable fractions and cancer deaths were also calculated. In total, 1,332,526 adult cancer deaths (age ≥ 20 years), from 5,565 Brazilian municipalities, covering 136 million adults were included. The mean annual wildfire-related PM2.5 concentration was 2.38 µg/m3, and the annual non-wildfire-related PM2.5 concentration was 8.20 µg/m3. The RR for mortality from all cancers was 1.02 (95% CI 1.01-1.03, p < 0.001) per 1-µg/m3 increase of wildfire-related PM2.5 concentration, which was higher than the RR per 1-µg/m3 increase of non-wildfire-related PM2.5 (1.01 [95% CI 1.00-1.01], p = 0.007, with p for difference = 0.003). Wildfire-related PM2.5 was associated with mortality from cancers of the nasopharynx (1.10 [95% CI 1.04-1.16], p = 0.002), esophagus (1.05 [95% CI 1.01-1.08], p = 0.012), stomach (1.03 [95% CI 1.01-1.06], p = 0.017), colon/rectum (1.08 [95% CI 1.05-1.11], p < 0.001), larynx (1.06 [95% CI 1.02-1.11], p = 0.003), skin (1.06 [95% CI 1.00-1.12], p = 0.003), breast (1.04 [95% CI 1.01-1.06], p = 0.007), prostate (1.03 [95% CI 1.01-1.06], p = 0.019), and testis (1.10 [95% CI 1.03-1.17], p = 0.002). For all cancers combined, the attributable deaths were 37 per 100,000 population and ranged from 18/100,000 in the Northeast Region of Brazil to 71/100,000 in the Central-West Region. Study limitations included a potential lack of assessment of the joint effects of gaseous pollutants, an inability to capture the migration of residents, and an inability to adjust for some potential confounders. CONCLUSIONS: Exposure to wildfire-related PM2.5 can increase the risks of cancer mortality for many cancer sites, and the effect for wildfire-related PM2.5 was higher than for PM2.5 from non-wildfire sources.

Third harmonic phase-shifted Bragg grating sensor.

Improving sensitivity is critical for the higher-order harmonic fiber Bragg grating sensors. To this aim, in this work, we have successfully introduced the phase-shift into the third harmonic fiber Bragg grating for tailoring a double-dip spectrum with a high finesse notch. The dual dips showed reversed responses for the intensity regarding the change of the temperature or axial strain, enabling a highly sensitive measuring regime using the intensity contrast between the two dips. Deduced from the sinusoidal responding curves, the highest temperature and the axial strain sensitivity could reach 0.964 dB/°C, and 0.0257 dB/µ ε, three-fold times the other intensity-based fiber sensors. This work may promote the higher-order harmonic gratings into applications for enriching wavelength utilization.

A prolactin-dependent sexually dimorphic mechanism of migraine chronification.

OBJECTIVE: Determination of possible sex differences in mechanisms promoting migraine progression and the contribution of prolactin and the prolactin long (PRLR-L) and short (PRLR-S) receptor isoforms. BACKGROUND: The majority of patients with chronic migraine and medication overuse headache are female. Prolactin is present at higher levels in women and increases migraine. Prolactin signaling at the PRLR-S selectively sensitizes nociceptors in female rodents, while expression of the PRLR-L is protective. METHODS: Medication overuse headache was modeled by repeated sumatriptan administration in male and female mice. Periorbital and hindpaw cutaneous allodynia served as a surrogate of migraine-like pain. PRLR-L and PRLR-S isoforms were measured in the trigeminal ganglion with western blotting. Possible co-localization of PRLR with serotonin 5HT1B and 5HT1D receptors was determined with RNAscope. Cabergoline, a dopamine receptor agonist that inhibits circulating prolactin, was co-administered with sumatriptan. Nasal administration of CRISPR/Cas9 plasmid was used to edit expression of both PRLR isoforms. RESULTS: PRLR was co-localized with 5HT1B or 5HT1D receptors in the ophthalmic region of female trigeminal ganglion. A single injection of sumatriptan increased serum PRL levels in female mice. Repeated sumatriptan promoted cutaneous allodynia in both sexes but down-regulated trigeminal ganglion PRLR-L, without altering PRLR-S, only in females. Co-administration of sumatriptan with cabergoline prevented allodynia and down-regulation of PRLR-L only in females. CRISPR/Cas9 editing of both PRLR isoforms in the trigeminal ganglion prevented sumatriptan-induced periorbital allodynia in females. INTERPRETATION: We identified a sexually dimorphic mechanism of migraine chronification that involves down-regulation of PRLR-L and increased signaling of circulating prolactin at PRLR-S. These studies reveal a previously unrecognized neuroendocrine mechanism linking the hypothalamus to nociceptor sensitization that increases the risk of migraine pain in females and suggest opportunities for novel sex-specific therapies including gene editing through nasal delivery of CRISPR/Cas9 constructs.

Projected Aerosol Changes Driven by Emissions and Climate Change Using a Machine Learning Method.

Projection of future aerosols and understanding the driver of the aerosol changes are of great importance in improving the atmospheric environment and climate change mitigation. The latest Coupled Model Intercomparison Project Phase 6 (CMIP6) provides various climate projections but limited aerosol output. In this study, future near-surface aerosol concentrations from 2015 to 2100 are predicted based on a machine learning method. The machine learning model is trained with global atmospheric chemistry model results and projects aerosols with CMIP6 multi-model simulations, creatively estimating future aerosols with all important species considered. PM2.5 (particulate matter less than 2.5 µm in diameter) concentrations in 2095 (2091-2100 mean) are projected to decrease by 40% in East Asia, 20-35% in South Asia, and 15-25% in Europe and North America, compared to those in 2020 (2015-2024 mean), under low-emission scenarios (SSP1-2.6 and SSP2-4.5), which are mainly due to the presumed emission reductions. Driven by the climate change alone, PM2.5 concentrations would increase by 10-25% in northern China and western U.S. and decrease by 0-25% in southern China, South Asia, and Europe under the high forcing scenario (SSP5-8.5). A warmer climate exerts a stronger modulation on global aerosols. Climate-driven global future aerosol changes are found to be comparable to those contributed by changes in anthropogenic emissions over many regions of the world in high forcing scenarios, highlighting the importance of climate change in regulating future air quality.

Global Perspective of Drought Impacts on Ozone Pollution Episodes.

Ozone (O3) pollution threatens global public health and damages ecosystem productivity. Droughts modulate surface O3 through meteorological processes and vegetation feedbacks. Unraveling these influences is difficult with traditional chemical transport models. Here, using an atmospheric chemistry-vegetation coupled model in combination with a suite of existing measurements, we investigate the drought impacts on global surface O3 and explore the main driving processes. Relative to the mean state, accelerated photochemical rates dominate the surface O3 enhancement during droughts except for eastern U.S. and western Europe, where reduced stomatal uptakes make comparable contributions. During 1990-2012, the simulated frequency of O3 pollution episodes in western Europe decreases greatly with a negative trend of -5.5 ± 6.6 days per decade following the reductions in anthropogenic emissions if meteorology is fixed. However, such decreased trend is weakened to -2.1 ± 3.8 days per decade, which is closer to the observed trend of -2.9 ± 1.1 days per decade when year-to-year meteorology is applied because increased droughts alone offset 43% of the effects from air pollution control. Our results highlight that more stringent controls of O3 precursors are necessary to mitigate the higher risks of O3 pollution episodes by more droughts in a warming world.

Linking the Fasting Blood Glucose Level to Short-Term-Exposed Particulate Constituents and Pollution Sources: Results from a Multicenter Cross-Sectional Study in China.

Ambient PM2.5 (fine particulate matter with aerodynamic diameters ≤ 2.5 µm) is thought to be associated with the development of diabetes, but few studies traced the effects of PM2.5 components and pollution sources on the change in the fasting blood glucose (FBG). In the present study, we assessed the associations of PM2.5 constituents and their sources with the FBG in a general Chinese population aged over 40 years. Exposure to PM2.5 was positively associated with the FBG level, and each interquartile range (IQR) increase in a lag period of 30 days (18.4 µg/m3) showed the strongest association with an elevated FBG of 0.16 mmol/L (95% confidence interval: 0.04, 0.28). Among various constituents, increases in exposed elemental carbon, organic matter, arsenic, and heavy metals such as silver, cadmium, lead, and zinc were associated with higher FBG, whereas barium and chromium were associated with lower FBG levels. The elevated FBG level was closely associated with the PM2.5 from coal combustion, industrial sources, and vehicle emissions, while the association with secondary sources was statistically insignificant. Improving air quality by tracing back to the pollution sources would help to develop well-directed policies to protect human health.

Widespread Wildfires Over the Western United States in 2020 Linked to Emissions Reductions During COVID-19.

Widespread wildfires struck the western United States in 2020, damaging properties and threating human lives. Meanwhile, the COVID-19 pandemic spread across the globe, which disrupted human activities. Here, we investigate the effects of the emissions reductions during the pandemic on fire weather in 2020 over the western United States by using an earth system model together with observations. We show that reductions in aerosols dominate the increases in wildfire risks, whereas greenhouse gas decrease counteracts this influence. The aerosol emissions reductions increased surface air temperature and decreased precipitation and relative humidity due to a weakened moisture transport, which explains one-third of the observed increase in wildfire risks during August-November over the western United States in 2020. This study suggests that COVID-19-related emissions reductions have an unexpected influence on wildfires, highlighting a different but important role of human activities in affecting wildfire risks.

The association between short-term exposure to ambient carbon monoxide and hospitalization costs for bronchitis patients: A hospital-based study.

Ambient carbon monoxide (CO) is associated with bronchitis morbidity, but there is no evidence concerning its correlation with hospitalization costs for bronchitis patients. This study aimed to investigate the relationship between short-term ambient CO exposure and hospitalization costs for bronchitis patients in Chongqing, China. Baseline data for 3162 hospitalized bronchitis patients from November 2013 to December 2019 were collected. Multiple linear regression analysis was used to determine the association, delayed and cumulative, between short-term CO exposure and hospitalization costs. Additionally, subgroup analyses were performed by gender, age, season, and comorbidity. Positive association between CO and hospitalization costs for bronchitis patients was observed. The strongest association was observed at lag 015 days, with per 1 mg/m3 increase of CO concentrations corresponded to 5834.40 Chinese Yuan (CNY) (95% CI: 2318.71, 9350.08; P < 0.001) (845.97 US dollars) increment in hospitalization costs. Stratified analysis results showed that the association was more obvious among those males, elderly, with comorbidities, and in warm seasons. More importantly, there was strongest correlation between CO and bronchitis patients with coronary heart disease. In summary, short-term exposure to ambient CO, even lower than Chinese and WHO standards, can be associated with increased hospitalization costs for bronchitis. Controlling CO exposure can be helpful to reduce medical burden associated with bronchitis patients. The results also suggest that when setting air quality standards and formulating preventive measures, susceptible subpopulations ought to be considered.

Correlation between CT images of lateral plateau and lateral meniscus injuries in patients with Schatzker II tibial plateau fractures:a retrospective study.

BACKGROUND: There is a great deal of controversy on whether routine MRI examination is needed for fresh fractures while the vast majority of patients with tibial plateau fractures (TPFs) receive preoperative X-ray and CT examinations. The purpose of the study was to analyze the exact correlation between CT images of lateral plateau and lateral meniscus injuries in Schatzker II TPFs. METHODS: A total of 296 patients with Schatzker II TPFs from August 2012 to January 2021 in two trauma centers were enrolled for the analysis. According to the actual situation during open reduction internal fixation (ORIF) and knee arthroscopic surgery, patients were divided into meniscus injury (including rupture, incarceration, etc.) and non-meniscus injury groups. The values of both lateral plateau depression (LPD) and lateral plateau widening (LPW) of lateral tibial plateau on CT images were measured, and their correlation with lateral meniscus injury was then analyzed. The relevant receiver operating characteristic (ROC) curve was drawn to evaluate the optimal cut-off point of the two indicators which could predict meniscus injury. RESULTS: The intra- and inter-observer reliabilities of LPD and LPW were acceptable (intraclass correlation coefficient (ICC) > 0.8). The average LPD was 13.2 ± 3.2 mm while the average value of the group without meniscus injury was 9.4 ± 3.2 mm. The difference between the two groups was statistically significant (P < 0.05). The average LPW was 8.0 ± 1.4 mm and 6.8 ± 1.6 mm in meniscus injury and non-meniscus injury groups with a significant difference (P < 0.05). The optimal predictive cut-off value of LPD and LPW was 7.9 mm (sensitivity-95.0%, specificity-58.8%, area under the curve (AUC-0.818) and 7.5 mm (sensitivity-70.0%, specificity - 70.6%, AUC - 0.724), respectively. The meniscus injury group mainly showed injuries involving the mid-body and posterior horn of lateral meniscus (98.1%, 157/160). CONCLUSIONS: The mid-body and posterior horn of lateral meniscus injury is more likely to occur in patients with Schatzker II TPFs when LPD > 7.9 mm and/or LPW > 7.5 mm on CT. These findings will definitely provide guidance for orthopedic surgeons in treating such injuries. During the operation, more attention is required be paid to the treatment of the meniscus and the possible fracture reduction difficulties and poor alignment caused by meniscus rupture and incarceration should be fully considered in order to achieve better surgical results.

Time-Dependent Changes in Protein Composition of Medial Prefrontal Cortex in Rats with Neuropathic Pain.

Chronic pain is associated with time-dependent structural and functional reorganization of the prefrontal cortex that may reflect adaptive pain compensatory and/or maladaptive pain-promoting mechanisms. However, the molecular underpinnings of these changes and whether there are time-dependent relationships to pain progression are not well characterized. In this study, we analyzed protein composition in the medial prefrontal cortex (mPFC) of rats at two timepoints after spinal nerve ligation (SNL) using two-dimensional gel electrophoresis (2D-ELFO) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). SNL, but not sham-operated, rats developed persistent tactile allodynia and thermal hyperalgesia, confirming the presence of experimental neuropathic pain. Two weeks after SNL (early timepoint), we identified 11 proteins involved in signal transduction, protein transport, cell homeostasis, metabolism, and apoptosis, as well as heat-shock proteins and chaperones that were upregulated by more than 1.5-fold compared to the sham-operated rats. Interestingly, there were only four significantly altered proteins identified at 8 weeks after SNL (late timepoint). These findings demonstrate extensive time-dependent modifications of protein expression in the rat mPFC under a chronic neuropathic pain state that might underlie the evolution of chronic pain characterized by early pain-compensatory and later aberrant mechanisms.

Enhanced PM2.5 Decreases and O3 Increases in China During COVID-19 Lockdown by Aerosol-Radiation Feedback.

We apply an online-coupled meteorology-chemistry model (WRF-Chem) embedded with an improved process analysis to examine aerosol-radiation feedback (ARF) impacts on effectiveness of emission control due to Coronavirus Disease 2019 (COVID-19) lockdown over North China Plain. Emission reduction alone induces PM2.5 decrease by 16.3 µg m-3 and O3 increase by 10.2 ppbv during COVID-19 lockdown. The ARF enhances PM2.5 decrease by 2.7 µg m-3 (16.6%) and O3 increase by 0.8 ppbv (7.8%). The ARF-induced enhancement of PM2.5 decline is mostly attributed to aerosol chemistry process, while enhancement of O3 rise is ascribed to physical advection and vertical mixing processes. A set of sensitivity experiments with emission reductions in different degrees indicate that the ARF-induced enhancements of PM2.5 declines (O3 rises) follow a robust linear relationship with the emission-reduction-induced PM2.5 decreases. The fitted relationship has an important implication for assessing the effectiveness of emission abatement at any extent.

Biogenic volatile organic compound emissions from leaves and fruits of apple and peach trees during fruit development.

Biogenic volatile organic compounds (BVOCs) are widely involved in a variety of atmospheric chemical processes due to their high reactivity and species diversity. To date, however, research on BVOCs in agroecosystems, particularly fruit trees, remains scarce despite their large cultivation area and economic interest. BVOC emissions from different organs (leaf or fruit) of apple and peach trees were investigated throughout the stages of fruit development (FS, fruit swelling; FC, fruit coloration; FM, fruit maturity; and FP, fruit postharvest) using a proton-transfer-reaction mass spectrometer. Results indicated that methanol was the most abundant compound emitted by the leaf (apple tree leaf 492.5 ± 47.9 ng/(g·hr), peach tree leaf 938.8 ±  154.5 ng/(g·hr)), followed by acetic acid and green leaf volatiles. Beside the above three compounds, acetaldehyde had an important contribution to the emissions from the fruit. Overall, the total BVOCs (sum of eight compounds studied in this paper) emitted by both leaf and fruit gradually decreased along the fruit development, although the effect was significant only for the leaf. The leaf (2020.8 ±  258.8 ng/(g·hr)) was a stronger BVOC emitter than the fruit (146.0 ± 45.7 ng/(g·hr)) (P = 0.006), and there were no significant differences in total BVOC emission rates between apple and peach trees. These findings contribute to our understanding on BVOC emissions from different plant organs and provide important insights into the variation of BVOC emissions across different fruit developmental stages.

Source Contributions to Ambient Fine Particulate Matter for Canada.

Understanding the sectoral contribution of emissions to fine particulate matter (PM2.5) offers information for air quality management, and for investigation of association with health outcomes. This study evaluates the contribution of different emission sectors to PM2.5 in 2013 for Canada using the GEOS-Chem chemical transport model, downscaled with satellite-based PM2.5. Despite the low population-weighted PM2.5 concentrations of 5.5 µg m-3 across Canada, we find that over 70% of population-weighted PM2.5 originates from Canadian sources followed by 30% from the contiguous United States. The three leading sectoral contributors to population-weighted PM2.5 over Canada are wildfires with 1.0 µg m-3 (17%), transportation with 0.96 µg m-3 (16%), and residential combustion with 0.91 µg m-3 (15%). The relative contribution to population-weighted PM2.5 of different sectors varies regionally with residential combustion as the leading contributor in Central Canada (19%), while wildfires dominate over Northern Canada (59%), Atlantic Canada (34%), and Western Canada (18%). The contribution from U.S. sources is larger over Central Canada (33%) than over Western Canada (17%), Atlantic Canada (17%), and Northern Canada (<2%). Sectoral trend analysis showed that the contribution from anthropogenic sources to population-weighted PM2.5 decreased from 7.1 µg m-3 to 3.4 µg m-3 over the past two decades.