From remotely-sensed solar-induced chlorophyll fluorescence to ecosystem structure, function, and service: Part II-Harnessing data.

Although our observing capabilities of solar-induced chlorophyll fluorescence (SIF) have been growing rapidly, the quality and consistency of SIF datasets are still in an active stage of research and development. As a result, there are considerable inconsistencies among diverse SIF datasets at all scales and the widespread applications of them have led to contradictory findings. The present review is the second of the two companion reviews, and data oriented. It aims to (1) synthesize the variety, scale, and uncertainty of existing SIF datasets, (2) synthesize the diverse applications in the sector of ecology, agriculture, hydrology, climate, and socioeconomics, and (3) clarify how such data inconsistency superimposed with the theoretical complexities laid out in (Sun et al., 2023) may impact process interpretation of various applications and contribute to inconsistent findings. We emphasize that accurate interpretation of the functional relationships between SIF and other ecological indicators is contingent upon complete understanding of SIF data quality and uncertainty. Biases and uncertainties in SIF observations can significantly confound interpretation of their relationships and how such relationships respond to environmental variations. Built upon our syntheses, we summarize existing gaps and uncertainties in current SIF observations. Further, we offer our perspectives on innovations needed to help improve informing ecosystem structure, function, and service under climate change, including enhancing in-situ SIF observing capability especially in "data desert" regions, improving cross-instrument data standardization and network coordination, and advancing applications by fully harnessing theory and data.

From remotely sensed solar-induced chlorophyll fluorescence to ecosystem structure, function, and service: Part I-Harnessing theory.

Solar-induced chlorophyll fluorescence (SIF) is a remotely sensed optical signal emitted during the light reactions of photosynthesis. The past two decades have witnessed an explosion in availability of SIF data at increasingly higher spatial and temporal resolutions, sparking applications in diverse research sectors (e.g., ecology, agriculture, hydrology, climate, and socioeconomics). These applications must deal with complexities caused by tremendous variations in scale and the impacts of interacting and superimposing plant physiology and three-dimensional vegetation structure on the emission and scattering of SIF. At present, these complexities have not been overcome. To advance future research, the two companion reviews aim to (1) develop an analytical framework for inferring terrestrial vegetation structures and function that are tied to SIF emission, (2) synthesize progress and identify challenges in SIF research via the lens of multi-sector applications, and (3) map out actionable solutions to tackle these challenges and offer our vision for research priorities over the next 5-10 years based on the proposed analytical framework. This paper is the first of the two companion reviews, and theory oriented. It introduces a theoretically rigorous yet practically applicable analytical framework. Guided by this framework, we offer theoretical perspectives on three overarching questions: (1) The forward (mechanism) question-How are the dynamics of SIF affected by terrestrial ecosystem structure and function? (2) The inference question: What aspects of terrestrial ecosystem structure, function, and service can be reliably inferred from remotely sensed SIF and how? (3) The innovation question: What innovations are needed to realize the full potential of SIF remote sensing for real-world applications under climate change? The analytical framework elucidates that process complexity must be appreciated in inferring ecosystem structure and function from the observed SIF; this framework can serve as a diagnosis and inference tool for versatile applications across diverse spatial and temporal scales.

Rapid response of nonstructural carbohydrate allocation and photosynthesis to short photoperiod, low temperature, or elevated CO2 in Pinus strobus.

During autumn, decreasing photoperiod and temperature temporarily perturb the balance between carbon uptake and carbon demand in overwintering plants, requiring coordinated adjustments in photosynthesis and carbon allocation to re-establish homeostasis. Here we examined adjustments of photosynthesis and allocation of nonstructural carbohydrates (NSCs) following a sudden shift to short photoperiod, low temperature, and/or elevated CO2 in Pinus strobus seedlings. Seedlings were initially acclimated to 14 h photoperiod (22/15°C day/night) and ambient CO2 (400 ppm) or elevated CO2 (800 ppm). Seedlings were then shifted to 8 h photoperiod for one of three treatments: no temperature change at ambient CO2 (22/15°C, 400 ppm), low temperature at ambient CO2 (12/5°C, 400 ppm), or no temperature change at elevated CO2 (22/15°C, 800 ppm). Short photoperiod caused all seedlings to exhibit partial nighttime depletion of starch. Short photoperiod alone did not affect photosynthesis. Short photoperiod combined with low temperature caused hexose accumulation and repression of photosynthesis within 24 h, followed by a transient increase in nonphotochemical quenching (NPQ). Under long photoperiod, plants grown under elevated CO2 exhibited significantly higher NSCs and photosynthesis compared to ambient CO2 plants, but carbon uptake exceeded sink capacity, leading to elevated NPQ; carbon sink capacity was restored and NPQ relaxed within 24 h after shift to short photoperiod. Our findings indicate that P. strobus rapidly adjusts NSC allocation, not photosynthesis, to accommodate short photoperiod. However, the combination of short photoperiod and low temperature, or long photoperiod and elevated CO2 disrupts the balance between photosynthesis and carbon sink capacity, resulting in increased NPQ to alleviate excess energy.

One size doesn't fit all: Attitudes towards work modify the relation between parental leave length and postpartum depression.

The present study aimed to investigate the relationship between parental leave length and maternal depressive symptoms at six- and twelve-months postpartum and whether this relation was influenced by women's attitudes towards leave, whether leave was paid or unpaid, and the reason they returned to work. The sample included 115 working women recruited during pregnancy as part of a larger longitudinal study. Analyses revealed that maternal attitudes toward leave influenced the association between leave length and depressive symptoms. Specifically, longer leaves were associated with increased depressive symptoms for women who missed their previous activities at work. Furthermore, women who missed work and had leave for 16 weeks or more, exhibited higher depressive symptoms at six- and twelve-months. Last, results also indicated that women who returned to work solely for monetary reasons exhibited more depressive symptoms at six-months postpartum than those who returned to work for other reasons. This study is among the first to show that women's attitudes towards parental leave and their individual reasons for returning to work are important factors to consider that may have potential implications for parental leave policies.

The physiological basis for estimating photosynthesis from Chla fluorescence.

Solar-induced Chl fluorescence (SIF) offers the potential to curb large uncertainties in the estimation of photosynthesis across biomes and climates, and at different spatiotemporal scales. However, it remains unclear how SIF should be used to mechanistically estimate photosynthesis. In this study, we built a quantitative framework for the estimation of photosynthesis, based on a mechanistic light reaction model with the Chla fluorescence of Photosystem II (SIFPSII ) as an input (MLR-SIF). Utilizing 29 C3 and C4 plant species that are representative of major plant biomes across the globe, we confirmed the validity of this framework at the leaf level. The MLR-SIF model is capable of accurately reproducing photosynthesis for all C3 and C4 species under diverse light, temperature, and CO2 conditions. We further tested the robustness of the MLR-SIF model using Monte Carlo simulations, and found that photosynthesis estimates were much less sensitive to parameter uncertainties relative to the conventional Farquhar, von Caemmerer, Berry (FvCB) model because of the additional independent information contained in SIFPSII . Once inferred from direct observables of SIF, SIFPSII provides 'parameter savings' to the MLR-SIF model, compared to the mechanistically equivalent FvCB model, and thus avoids the uncertainties arising as a result of imperfect model parameterization. Our findings set the stage for future efforts to employ SIF mechanistically to improve photosynthesis estimates across a variety of scales, functional groups, and environmental conditions.

ALT Levels in Treatment-Naive, Chronic Hepatitis B Patients with Concurrent Fatty Liver Disease: A US Nationwide Study.

INTRODUCTION: Treatment criteria for chronic hepatitis B (CHB) relies on ALT, which can be impacted by concurrent nonalcoholic fatty liver disease (NAFLD), but ALT data on patients with CHB and NAFLD are limited. We aimed to characterize ALT distribution in untreated CHB patients with NAFLD. METHODS: We retrospectively analyzed untreated US adults with CHB (533 with NAFLD, 3,172 without NAFLD) using the Clinformatics™ Data Mart Database (2003-2019). The main outcome was ALT elevation (>1× upper limit of normal, 35/25 U/L for men/women, respectively). Secondary outcomes were advanced fibrosis (via FIB-4 index) and factors associated with fibrosis. RESULTS: The majority of patients were Asian (61.0%) and hepatitis B e-antigen (HBeAg)-negative (90.4%). Patients with CHB and NAFLD were older (57.2 vs. 49.5 years, p < 0.001), more likely male (59.3% vs. 46.2%, p < 0.001), with higher percentages of advanced fibrosis (3.6% vs. 2.6%, p < 0.001) than those with CHB alone. CHB-NAFLD patients were more likely to have elevated ALT than those with CHB only, but this difference was only significant among those with low hepatitis B virus (HBV) DNA (38.1% vs. 25.6%, p < 0.001), not those with higher HBV DNA (>2,000 IU/mL). After adjusting for HBeAg, HBV DNA, and diabetes, NAFLD was not independently associated with advanced fibrosis (odds ratio 1.18, 95% confidence interval: 0.30-4.59, p = 0.81). DISCUSSION: CHB-NAFLD patients with HBV DNA below treatment threshold were more likely to have elevated ALT but not those with higher HBV DNA, suggesting that ALT threshold does not need to be raised for antiviral eligibility for CHB with NAFLD.

Sun-induced Chl fluorescence and its importance for biophysical modeling of photosynthesis based on light reactions.

Recent progress in observing sun-induced Chl fluorescence (SIF) provides an unprecedented opportunity to advance photosynthesis research in natural environments. However, we still lack an analytical framework to guide SIF studies and integration with the well-developed active fluorescence approaches. Here, we derive a set of coupled fundamental equations to describe the dynamics of SIF and its relationship with C3 and C4 photosynthesis. These equations show that, although SIF is dynamically as complex as photosynthesis, the measured SIF simplifies photosynthetic modeling from the perspective of light reactions by integrating over the dynamic complexities of photosynthesis. Specifically, the measured SIF contains direct information about the actual electron transport from photosystem II to photosystem I, giving a quantifiable link between light and dark reactions. With much-reduced requirements on inputs and parameters, the light-reactions-centric, SIF-based biophysical model complements the traditional, dark-reactions-centric biochemical model of photosynthesis. The SIF-photosynthesis relationship, however, is nonlinear. This is because photosynthesis saturates at high light whereas SIF has a stronger tendency to keep increasing, as fluorescence quantum yield has a relatively muted sensitivity to light levels. Successful applications of the SIF-based model of photosynthesis will depend on a predictive understanding of several previously underexplored physiological and biophysical processes. Advances can be facilitated by coordinated efforts in plant physiology, remote sensing, and eddy covariance flux observations.

Serum Aminotransferase Flares in Pregnant and Postpartum Women With Current or Prior Treatment for Chronic Hepatitis B.

BACKGROUND AND AIMS: Antiviral therapy is recommended for pregnant women with chronic hepatitis B (CHB) and hepatitis B virus (HBV) DNA>200,000 IU/mL, but there is less consensus on management of women who discontinue therapy in anticipation of pregnancy or who become pregnant while on therapy. The goal of this study was to describe flares in alanine aminotransferase (ALT) during pregnancy and postpartum in CHB women with current and/or prior treatment. METHODS: This was a multicenter, retrospective study of 67 pregnancies in 56 CHB women treated before and/or during pregnancy. Main outcomes were frequency, severity, and resolution of ALT flare (≥5× upper limit of normal or ≥3× baseline, whichever was higher). RESULTS: During pregnancy, ALT flares (95 to 1064 U/L) were observed in 16% (7/43) of women who stopped treatment before pregnancy and 31% (4/13) of women who discontinued treatment during first trimester, many of whom had high HBV DNA levels (4.9 to 8.0 log IU/mL). No flares (0/11) were observed in women who continued treatment. Postpartum ALT flares (104 to 1584 U/L) were observed in 0% (0/15) of women who were completely untreated during pregnancy, 29% (2/7) of women who discontinued treatment in first trimester, 33% (3/9) of women who stopped treatment at delivery, and 22% (4/18) of women who continued treatment postpartum. CONCLUSIONS: In previously treated women with CHB, ALT flares were common during pregnancy and postpartum, especially if antiviral therapy was discontinued shortly before pregnancy, during first trimester, or at delivery. Thus, these pregnant women should be monitored closely throughout pregnancy and the early postpartum period; larger studies are needed to further characterize the natural history of HBV infection during pregnancy and postpartum.

Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine.

Rising global temperature and CO2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO2, affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 µL L-1) or elevated (800 µmol mol-1) CO2, and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO2 (LTAC), elevated temperature/ambient CO2 (ETAC), or elevated temperature/elevated CO2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus Our findings suggest that exposure to elevated temperature and CO2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low-temperature events changes, this is unlikely to increase risk of freezing damage in P. strobus seedlings.

Serum Alanine Aminotransferase and Hepatitis B DNA Flares in Pregnant and Postpartum Women with Chronic Hepatitis B.

OBJECTIVES: Alterations in the immune system during pregnancy have been associated with reactivation of hepatitis B virus (HBV) in chronic hepatitis B (CHB) women. However, the effects of pregnancy on CHB remain not well understood. The goal of this study was to examine flares in HBV DNA and serum alanine aminotransferase (ALT) during pregnancy and postpartum in CHB women untreated prior to pregnancy. METHODS: This was a multicenter retrospective study of 113 pregnancies in 101 CHB women who presented during pregnancy at two community gastroenterology clinics and two tertiary medical centers in the United States during 1997-2015. Outcomes analyzed included onset, severity, and resolution of flares in HBV and ALT that occurred prior to starting antiviral therapy, if antiviral therapy was subsequently initiated. Women who initiated antiviral therapy during pregnancy were not included in the analysis of postpartum flares. RESULTS: HBV DNA flares were observed in 9% (8/90) of women during pregnancy and 4% (2/48) of women during postpartum. Flares in ALT (99-2522 U/l) were observed in 6% (7/112) of women during pregnancy and 10% (5/51) of women within the first 3 months of delivery. Age, HBeAg positivity, baseline HBV DNA, baseline ALT, gravida, and parity were not found to be significant predictors of flare. CONCLUSIONS: Flares in HBV DNA and ALT can occur during late pregnancy and early postpartum in CHB women, and can be severe. Women with CHB should therefore be closely monitored during pregnancy and early postpartum.

Effect of Far-Red Light on Biomass Accumulation, Plant Morphology, and Phytonutrient Composition of Ruby Streaks Mustard at Microgreen, Baby Leaf, and Flowering Stages.

Far-red (FR) light influences plant development significantly through shade avoidance response and photosynthetic modulation, but there is limited knowledge on how FR treatments influence the growth and nutrition of vegetables at different maturity stages in controlled environment agriculture (CEA). Here, we comprehensively investigated the impacts of FR on the yield, morphology, and phytonutrients of ruby streaks mustard (RS) at microgreen, baby leaf, and flowering stages. Treatments including white control, white with supplementary FR, white followed by singularly applied FR, and enhanced white (WE) matching the extended daily light integral (eDLI) of FR were designed for separating the effects of light intensity and quality. Results showed that singular and supplemental FR affected plant development and nutrition similarly throughout the growth cycle, with light intensity and quality playing varying roles at different stages. Specifically, FR did not affect the fresh and dry weight of microgreens but increased those values for baby leaves, although not as effectively as WE. Meanwhile, FR caused significant morphological change and accelerated the development of leaves, flowers, and seedpods more dramatically than WE. With regard to phytonutrients, light treatments affected the metabolomic profiles for baby leaves more dramatically than microgreens and flowers. FR decreased the glucosinolate and anthocyanin contents in microgreens and baby leaves, while WE increased the contents of those compounds in baby leaves. This study illustrates the complex impacts of FR on RS and provides valuable information for selecting optimal lighting conditions in CEA.

Real-world experience with interferon-free, direct acting antiviral therapies in Asian Americans with chronic hepatitis C and advanced liver disease.

Real-life data on interferon (IFN)-free direct acting antiviral (DAA) therapies for chronic hepatitis C (CHC) is limited for Asian Americans.To evaluate sustained virologic response (SVR) and adverse events (AE) in Asian Americans treated with sofosbuvir (SOF)-based, IFN-free DAA therapies.This is a retrospective study of 110 consecutive Asian Americans with HCV genotypes 1 to 3 or 6 treated with IFN-free SOF-based regimens for 8 to 24 weeks between February 2014 and March 2016 at a university center in Northern California.Mean age was 63 ±â€Š12 years, mean BMI was 25 ±â€Š6 (kg/m), and about half (52%) were male. Most patients were infected with HCV genotype 1 (HCV-1, 64%), followed by HCV-2 (14%), HCV-6 (13%), and HCV-3 (8%). Half had cirrhosis, and the majority of these (67%) had decompensation. Overall SVR12 was 93% (102/110), and highest among patients without cirrhosis, liver transplant, or HCC (100%, 37/37). SVR12 was lower among patients with HCC (82%, 14/17), decompensated cirrhosis (84%, 31/37), or liver transplant (89%, 17/19), regardless of treatment and genotype. Most common AEs were anemia (25%), fatigue (20%), and headache (12%). Anemia was highest in patients receiving SOF/RBV (67%). There was 1 treatment-unrelated serious adverse effect (SAE). There were 7 dose reductions due to anemia or fatigue from RBV and 2 treatment discontinuations due to fatigue or loss of insurance authorization.This real-life cohort of Asian American CHC patients treated with IFN-free SOF-based therapies showed high overall treatment response and good tolerability, despite very high rates of advanced disease and prior treatment failure.

Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings.

Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, +1.5°C/+3°C during day/night). Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC), and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12 h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10 h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20-30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis, enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our field experiments.

Combined administration of secretin and oxytocin inhibits chronic colitis and associated activation of forebrain neurons.

BACKGROUND: The pathogenesis of inflammatory bowel disease is unknown; however, the disorder is aggravated by psychological stress and is itself psychologically stressful. Chronic intestinal inflammation, moreover, has been reported to activate forebrain neurons. We tested the hypotheses that the chronically inflamed bowel signals to the brain through the vagi and that administration of a combination of secretin (S) and oxytocin (OT) inhibits this signaling. METHODS: Three daily enemas containing 2,4,6-trinitrobenzene sulfonic acid (TNBS), which were given to rats produced chronic colitis and ongoing activation of Fos in brain neurons. KEY RESULTS: Fos was induced in neurons in the paraventricular nucleus of the hypothalamus, basolateral amygdala, central amygdala, and piriform cortex. Subdiaphragmatic vagotomy failed to inhibit this activation of Fos, suggesting that colitis activates forebrain neurons independently of the vagi. When administered intravenously, but not when given intracerebroventricularly, in doses that were individually ineffective, combined S/OT prevented colitis-associated activation of central neurons. Strikingly, S/OT decreased inflammatory infiltrates into the colon and colonic expression of tumor necrosis factor-alpha and interferon-gamma. CONCLUSIONS & INFERENCES: These observations suggest that chronic colonic inflammation is ameliorated by the systemic administration of S/OT, which probably explains the parallel ability of systemic S/OT to inhibit the colitis-associated activation of forebrain neurons. It is possible that S and OT, which are endogenous to the colon, might normally combine to restrict the severity of colonic inflammatory responses and that advantage might be taken of this system to develop novel means of treating inflammation-associated intestinal disorders.