ABSTRACT
12-Oxo-phytodienoic acid reductases (OPRs) perform vital functions in plants. However, few studies have been reported in sugarcane (Saccharum spp.), and it is of great significance to systematically investigates it in sugarcane. Here, 61 ShOPRs, 32 SsOPRs, and 36 SoOPRs were identified from R570 (Saccharum spp. hybrid cultivar R570), AP85-441 (Saccharum spontaneum), and LA-purple (Saccharum officinarum), respectively. These OPRs were phylogenetically classified into four groups, with close genes similar structures. During evolution, OPR gene family was mainly expanded via whole-genome duplications/segmental events and predominantly underwent purifying selection, while sugarcane OPR genes may function differently in response to various stresses. Further, ScOPR2, a tissue-specific OPR, which was localized in cytoplasm and cell membrane and actively response to salicylic acid (SA), methyl jasmonate, and smut pathogen (Sporisorium scitamineum) stresses, was cloned from sugarcane. In addition, both its transient overexpression and stable overexpression enhanced the resistance of transgenic plants to pathogen infection, most probably through activating pathogen-associated molecular pattern/pattern-recognition receptor-triggered immunity, producing reactive oxygen species, and initiating mitogen-activated protein kinase cascade. Subsequently, the transmission of SA and hypersensitive reaction were triggered, which stimulated the transcription of defense-related genes. These findings provide insights into the function of ScOPR2 gene for disease resistance.
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Degradable biomedical elastomers (DBE), characterized by controlled biodegradability, excellent biocompatibility, tailored elasticity, and favorable network design and processability, have become indispensable in tissue repair. This review critically examines the recent advances of biodegradable elastomers for tissue repair, focusing mainly on degradation mechanisms and evaluation, synthesis and crosslinking methods, microstructure design, processing techniques, and tissue repair applications. The review explores the material composition and cross-linking methods of elastomers used in tissue repair, addressing chemistry-related challenges and structural design considerations. In addition, this review focuses on the processing methods of two- and three-dimensional structures of elastomers, and systematically discusses the contribution of processing methods such as solvent casting, electrostatic spinning, and three-/four-dimensional printing of DBE. Furthermore, we describe recent advances in tissue repair using DBE, and include advances achieved in regenerating different tissues, including nerves, tendons, muscle, cardiac, and bone, highlighting their efficacy and versatility. The review concludes by discussing the current challenges in material selection, biodegradation, bioactivation, and manufacturing in tissue repair, and suggests future research directions. This concise yet comprehensive analysis aims to provide valuable insights and technical guidance for advances in DBE for tissue engineering.
Subject(s)
Biocompatible Materials , Elastomers , Regenerative Medicine , Tissue Engineering , Humans , Elastomers/chemistry , Biocompatible Materials/chemistry , AnimalsABSTRACT
Climate change-related environmental stresses can negatively impact crop productivity and pose a threat to sustainable agriculture. Plants have a remarkable innate ability to detect a broad array of environmental cues, including stresses that trigger stress-induced regulatory networks and signaling pathways. Transcriptional activation of plant pathogenesis related-1 (PR-1) proteins was first identified as an integral component of systemic acquired resistance in response to stress. Consistent with their central role in immune defense, overexpression of PR-1s in diverse plant species is frequently used as a marker for salicylic acid (SA)-mediated defense responses. Recent advances demonstrated how virulence effectors, SA signaling cascades, and epigenetic modifications modulate PR-1 expression in response to environmental stresses. We and others showed that transcriptional regulatory networks involving PR-1s could be used to improve plant resilience to stress. Together, the results of these studies have re-energized the field and provided long-awaited insights into a possible function of PR-1s under extreme environmental stress.
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BACKGROUND: Premature mortality is a significant part of the epilepsy burden and may vary across populations, especially between high-income and lower- and middle-income countries. People with epilepsy in China are approximately a fifth of the global population with epilepsy. Previous studies were unlikely to represent the situation in China due to limitations in design, methods, sample size, follow-up time, and other inherent population heterogeneity. SUMMARY: By summarising the evidence on the mortality characteristics in Chinese populations with epilepsy in the last 6 decades, we found a median mortality rate of 14.7 (6.8-74.4)/1,000 person-years and a median standardised mortality ratio (SMR) of 4.4 (2.6-12.9) in population-based studies, and a median mortality rate of 12.3 (9.5-101.5)/1,000 person-years and a median SMR of 3.0 (1.5-5.1) in hospital-based studies. Vascular diseases, complications of diabetes, and accidental injuries were the leading causes of death. Risk factors for mortality were reported as older age, male, longer duration, and higher frequency of seizures. Case fatality ratios of status epilepticus in adults were higher than in children, and both increased with follow-up time. Mortality in people with symptomatic epilepsy was high and varied across different primary diseases. KEY MESSAGES: The highest mortality rate and sudden unexpected death in epilepsy (SUDEP) incidence were reported from the least developed areas in China. Accidental injuries were the most common causes of epilepsy-related deaths, while the incidence of SUDEP may be underestimated in Chinese populations. Further research is warranted to improve the understanding of premature mortality risk so that preventative measures can be introduced to improve the situation.
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BACKGROUND: Presently, a consistent strategy for determining the stability of unruptured intracranial aneurysms (UIAs) in elderly patients is lacking, primarily due to the unique characteristics of this demographic. Our objective was to assess the risk factors contributing to aneurysm instability (growth or rupture) within the elderly population. METHODS: In this study, we compiled data from follow-up patients with UIAs spanning from November 2016 to August 2021. We specifically focused on patients aged ≥ 60 years. Clinical histories were gathered, and morphological parameters of aneurysms were measured. The growth of aneurysms was determined using the computer-assisted semi-automated measurement (CASAM). Growth and rupture rates of UIAs were calculated, and both univariate and multivariate Cox regression analyses were conducted. Additionally, Kaplan-Meier survival curves were plotted. RESULTS: A total of 184 patients with 210 aneurysms were enrolled in the study. The follow-up period encompasses 506.6 aneurysm-years and 401.4 patient-years. Among all the aneurysms, 23 aneurysms exhibited growth, with an annual aneurysm growth rate of 11.0%, and 1 (4.5%) experienced rupture, resulting in an annual aneurysm rupture rate of 0.21%. Multivariate Cox analysis identified poorly controlled hypertension (P = 0.011) and high-risk aneurysms (including anterior cerebral artery (ACA), anterior communicating artery (AcoA), posterior communicating artery aneurysm (PcoA), posterior circulation (PC) > 4 mm or distal internal carotid artery (ICAd), middle cerebral artery (MCA), and PC > 7 mm) (P = 0.006) as independent risk factors for the development of unstable aneurysms. CONCLUSIONS: In the elderly, poorly controlled hypertension and high-risk aneurysms emerge as significant risk factors for aneurysm instability. This underscores the importance of rigorous surveillance or timely intervention in patients presenting with these risk factors.
Subject(s)
Aneurysm, Ruptured , Hypertension , Intracranial Aneurysm , Humans , Aged , Adult , Child , Intracranial Aneurysm/epidemiology , Risk Factors , Aneurysm, Ruptured/epidemiology , Anterior Cerebral ArteryABSTRACT
Plant resistance against biotic stressors is significantly influenced by pathogenesis-related 1 (PR1) proteins. This study examines the systematic identification and characterization of PR1 family genes in sugarcane (Saccharum spontaneum Np-X) and the transcript expression of selected genes in two sugarcane cultivars (ROC22 and Zhongtang3) in response to Ustilago scitaminea pathogen infection. A total of 18 SsnpPR1 genes were identified at the whole-genome level and further categorized into four groups. Notably, tandem and segmental duplication occurrences were detected in one and five SsnpPR1 gene pairs, respectively. The SsnpPR1 genes exhibited diverse physio-chemical attributes and variations in introns/exons and conserved motifs. Notably, four SsnpPR1 (SsnpPR1.02/05/09/19) proteins displayed a strong protein-protein interaction network. The transcript expression of three SsnpPR1 (SsnpPR1.04/06/09) genes was upregulated by 1.2-2.6 folds in the resistant cultivar (Zhongtang3) but downregulated in the susceptible cultivar (ROC22) across different time points as compared to the control in response to pathogen infection. Additionally, SsnpPR1.11 was specifically upregulated by 1.2-3.5 folds at 24-72 h post inoculation (hpi) in ROC22, suggesting that this gene may play an important negative regulatory role in defense responses to pathogen infection. The genetic improvement of sugarcane can be facilitated by our results, which also establish the basis for additional functional characterization of SsnpPR1 genes in response to pathogenic stress.
Subject(s)
Gene Expression Regulation, Plant , Plant Diseases , Plant Proteins , Saccharum , Stress, Physiological , Ustilago , Saccharum/genetics , Saccharum/microbiology , Plant Proteins/genetics , Plant Proteins/metabolism , Ustilago/genetics , Ustilago/pathogenicity , Plant Diseases/microbiology , Plant Diseases/genetics , Stress, Physiological/genetics , Disease Resistance/genetics , Multigene Family , PhylogenyABSTRACT
Relative sea level rise (SLR) increasingly impacts coastal ecosystems through the formation of ghost forests. To predict the future of coastal ecosystems under SLR and changing climate, it is important to understand the physiological mechanisms underlying coastal tree mortality and to integrate this knowledge into dynamic vegetation models. We incorporate the physiological effect of salinity and hypoxia in a dynamic vegetation model in the Earth system land model, and used the model to investigate the mechanisms of mortality of conifer forests on the west and east coast sites of USA, where trees experience different form of sea water exposure. Simulations suggest similar physiological mechanisms can result in different mortality patterns. At the east coast site that experienced severe increases in seawater exposure, trees loose photosynthetic capacity and roots rapidly, and both storage carbon and hydraulic conductance decrease significantly within a year. Over time, further consumption of storage carbon that leads to carbon starvation dominates mortality. At the west coast site that gradually exposed to seawater through SLR, hydraulic failure dominates mortality because root loss impacts on conductance are greater than the degree of storage carbon depletion. Measurements and modeling focused on understanding the physiological mechanisms of mortality is critical to reducing predictive uncertainty.
Subject(s)
Ecosystem , Tracheophyta , Seawater , Trees , CarbonABSTRACT
A novel base-catalyzed method for the synthesis of luminescent benzothiazole derivatives had been developed under metal-free conditions via C-S bond formation, which provided an efficient, convenient, and mild alternative method for constructing substituted benzothiazoles. As-prepared benzothiazole derivatives thus produced emissions in solution with quantum yield up to 85%. In addition, they still exhibited fairly strong fluorescence in the solid state. Furthermore, the compounds were used as a facile "On-Off" fluorescence probe to create handy test strips for detecting NaClO by naked eyes.
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Biocompatible chitosan-based hydrogels have attracted extensive attention in wound dressing due to their human skin-like tissue characteristics. However, it is a crucial challenge to fabricate chitosan-based hydrogels with versatile properties, including flexibility, stretchability, adhesivity, and antibacterial activity. In this work, a kind of chitosan-based hydrogels with integrated functionalities are facilely prepared by solution polymerization of acrylamide (AAm) and sodium p-styrene sulfonate (SS) in the presence of quaternized carboxymethyl chitosan (QCMCS). Due to the dual cross-linking between QCMCS and P(AAm-co-SS), the optimized QCMCS/P(AAm-co-SS) hydrogel exhibits tough mechanical properties (0.767 MPa tensile stress and 1100% fracture strain) and moderate tissue adhesion (11.4 kPa). Moreover, biological evaluation in vitro illustrated that as-prepared hydrogel possesses satisfactory biocompatibility, hemocompatibility, and excellent antibacterial ability (against S. aureus and E. coli are 98.8% and 97.3%, respectively). Then, the hydrogels are tested in a rat model for bacterial infection incision in vivo, and the results show that they can significantly accelerate epidermal regeneration and wound closure. This is due to their ability to reduce the inflammatory response, promote the formation of collagen deposition and granulation tissue. The proposed chitosan-based antibacterial hydrogels have the potential to be a highly effective wound dressing in clinical wound healing.
Subject(s)
Chitosan , Rats , Animals , Humans , Hydrogels/pharmacology , Adhesives , Escherichia coli , Staphylococcus aureus , Anti-Bacterial Agents/pharmacology , BandagesABSTRACT
Over the past decade, a proliferation of research has used nanoparticles to deliver gaseous signaling molecules for medical purposes. The discovery and revelation of the role of gaseous signaling molecules have been accompanied by nanoparticle therapies for their local delivery. While most of them have been applied in oncology, recent advances have demonstrated their considerable potential in diagnosing and treating orthopedic diseases. Three of the currently recognized gaseous signaling molecules, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S), are highlighted in this review along with their distinctive biological functions and roles in orthopedic diseases. Moreover, this review summarizes the progress in therapeutic development over the past ten years with a deeper discussion of unresolved issues and potential clinical applications.
Subject(s)
Gases , Hydrogen Sulfide , Signal Transduction , Hydrogen Sulfide/therapeutic use , Carbon Monoxide , Nitric OxideABSTRACT
BACKGROUND: In China, data on the prevalence and characteristics of comorbid stroke and traumatic brain injury (TBI) in real-world populations are still lacking but of paramount importance for the evidence-based prevention and control of the comorbidity of the two diseases. This study aimed to investigate the prevalence and characteristics of comorbid stroke and TBI in a real-world population. METHODS: In 2013, a nationally representative, door-to-door survey on stroke and TBI using a complex, multistage, probability sampling design was conducted among approximately 600,000 participants from 155 urban and rural areas in China (Ethic ID: KY2013-006-01). The weighted prevalence of comorbid stroke and TBI was estimated using individuals' final weight. A Poisson regression analysis was used to compare the rate ratio of the comorbidity prevalence among different subgroups of the population, including age, sex, place of residence, and geographic location subgroups. For analyses of associations between the comorbidities and predictors of interest, all other variables were adjusted for in a multinomial logistic regression model. RESULTS: Among the 596,536 people, 219 patients with comorbid stroke and TBI were identified. The point prevalence of comorbid stroke and TBI weighted to the China 2010 census population was 29.30 (95% CI: 22.69-37.84) per 100,000 population in China. The adjusted prevalence of post-TBI stroke in patients with previous TBI was significantly higher than that of post-stroke TBI in patients with previous stroke (6021.3 vs. 811.1 per 100,000 people; rate ratio: 11.001; 95% CI: 8.069-14.998). Patients with nonconcussion had significantly higher rates of both pre-stroke TBI (odds ratio: 4.694; 95% CI: 3.296-6.687) and post-stroke TBI (odds ratio: 6.735; 95% CI: 3.719-12.194) than patients with concussion. Compared to patients with ischaemic stroke, patients with subarachnoid haemorrhage (odds ratio: 2.044; 95% CI: 1.097-3.809) and intracerebral haemorrhage (odds ratio: 1.903; 95% CI: 1.296-2.795) had significantly higher rates of post-TBI stroke. CONCLUSIONS: The high prevalence of stroke among TBI patients is becoming a new public health issue. TBI patients, especially those with nonconcussion TBI, are more likely to develop comorbid stroke and TBI than stroke patients, especially ischaemic stroke patients.
Subject(s)
Brain Injuries, Traumatic , Brain Ischemia , Ischemic Stroke , Stroke , Humans , Stroke/epidemiology , Prevalence , Cross-Sectional Studies , Brain Ischemia/epidemiology , Comorbidity , Brain Injuries, Traumatic/epidemiology , Ischemic Stroke/epidemiologyABSTRACT
Depression is among the most frequent psychiatric comorbid conditions in Alzheimer disease (AD). However, pharmacotherapy for depressive disorders in AD is still a big challenge, and the data on the efffcacy of current antidepressants used clinically for depressive symptoms in patients with AD remain inconclusive. Here we investigated the mechanism of the interactions between depression and AD, which we believe would aid in the development of pharmacological therapeutics for the comorbidity of depression and AD. Female APP/PS1/Tau triple transgenic (3×Tg-AD) mice at 24 months of age and age- and sex-matched wild-type (WT) mice were used. The shuttle-box passive avoidance test (PAT) were implemented to assess the abilities of learning and memory, and the open field test (OFT) and the tail suspension test (TST) were used to assess depression-like behavior. High-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) was used to detect the level of neurotransmitters related to depression in the hippocampus of mice. The data was identified by orthogonal projections to latent structures discriminant analysis (OPLS-DA). Most neurotransmitters exert their effects by binding to the corresponding receptor, so the expression of relative receptors in the hippocampus of mice was detected using Western blot. Compared to WT mice, 3×Tg-AD mice displayed significant cognitive impairment in the PAT and depression-like behavior in the OFT and TST. They also showed significant decreases in the levels of L-tyrosine, norepinephrine, vanillylmandelic acid, 5-hydroxytryptamine, and acetylcholine, in contrast to significant increases in 5-hydroxyindoleacetic acid, L-histidine, L-glutamine, and L-arginine in the hippocampus. Moreover, the expression of the alpha 1a adrenergic receptor (ADRA1A), serotonin 1 A receptor (5HT1A), and γ-aminobutyric acid A receptor subunit alpha-2 (GABRA2) was significantly downregulated in the hippocampus of 3×Tg-AD mice, while histamine H3 receptor (H3R) expression was significantly upregulated. In addition, the ratio of phosphorylated cAMP-response element-binding protein (pCREB) and CREB was significantly decreased in the hippocampus of 3×Tg-AD mice than WT mice. We demonstrated in the present study that aged female 3×Tg-AD mice showed depression-like behavior accompanied with cognitive dysfunction. The complex and diverse mechanism appears not only relevant to the imbalance of multiple neurotransmitter pathways, including the transmitters and receptors of the monoaminergic, GABAergic, histaminergic, and cholinergic systems, but also related to the changes in L-arginine and CREB signaling molecules.
Subject(s)
Alzheimer Disease , Cognitive Dysfunction , Mice , Female , Animals , Alzheimer Disease/complications , Alzheimer Disease/genetics , Alzheimer Disease/drug therapy , Mice, Transgenic , Tandem Mass Spectrometry , Depression/drug therapy , Cognitive Dysfunction/metabolism , Hippocampus/metabolism , Neurotransmitter Agents/metabolism , Disease Models, Animal , Amyloid beta-Peptides/pharmacology , tau Proteins/metabolismABSTRACT
Climate warming may induce growth decline in warm-temperate areas subjected to seasonal soil moisture deficit, whereas increasing atmospheric CO2 concentration (Ca) is expected to enhance tree growth. An accurate understanding of tree growth and physiological processes responding to climate warming and increasing Ca is critical. Here, we analyzed tree-ring stable carbon isotope and wood anatomical traits of Pinus tabuliformis from Qinling Mountains in China to understand how lumen diameter (LD) determining potential hydraulic conductivity and cell-wall thickness (CWT) determining carbon storage responded to climate and Ca. The effects of climate and Ca on intrinsic water-use efficiency (iWUE) were isolated, and iWUE values due to only-climate (iWUEClim) and only-CO2 effects (iWUECO2) were obtained. During a low-iWUE period, the influences of climate on earlywood (EW) LD and latewood (LW) CWT prevailed. During a high-iWUE period, CO2 fertilization promoted cell enlargement and carbon storage but this was counteracted by a negative influence of climate warming. The limiting direct effects of iWUEClim and indirect effects of climate on EW LD were greater than on LW CWT. P. tabuliformis in temperate forests will face a decline of growth and carbon fixation, but will produce embolism-resistant tracheids with narrow lumen responding to future hotter droughts.
Subject(s)
Water , Wood , Carbon Dioxide , Climate , Trees , Forests , Carbon , DroughtsABSTRACT
Recently, targeting myeloid-derived suppressor cells (MDSCs) which mainly play an immunosuppressive role in tumor microenvironment has become a hot spot in tumor immunotherapy. This study focuses on biological effect of ginger polysaccharide extracted from natural plants on promoting apoptosis of MDSCs by regulating lipid metabolism. An MTT assay was used to detect the inhibitory effect of ginger polysaccharide on the growth of an MDSC-like cell line (MSC-2). The apoptosis-promoting effect of ginger polysaccharide on MSC-2 cells was detected by flow cytometry. Expression levels of apoptosis proteins (caspase 9 and Bcl-2) and lipid metabolism enzymes (fatty acid synthase (FASN) and diacylglycerol acyltransferase 2) in MSC-2 cells treated with different concentrations of ginger polysaccharide were detected by western blot assay. Nile red staining was used to quantitatively detect the effect of ginger polysaccharide on lipid droplet synthesis. Ginger polysaccharide inhibited proliferation of MSC-2 cells and promoted their apoptosis by upregulating pro-apoptotic caspase 9 protein, downregulating anti-apoptotic Bcl-2 protein, inhibiting expression of FASN and diacylglycerol acyltransferase 2 (key enzymes in fatty acid synthesis and lipid droplet formation, respectively). Ginger polysaccharide promoted apoptosis of MDSCs by regulating key lipid metabolism enzymes, inhibiting fatty acid synthesis and lipid droplet accumulation, and reducing the energy supply of cells.
Subject(s)
Myeloid-Derived Suppressor Cells , Zingiber officinale , Caspase 9/metabolism , Lipid Metabolism , Diacylglycerol O-Acyltransferase/metabolism , Diacylglycerol O-Acyltransferase/pharmacology , Apoptosis , Apoptosis Regulatory Proteins/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Polysaccharides/pharmacology , Polysaccharides/metabolism , Fatty Acids/pharmacology , Cell ProliferationABSTRACT
BACKGROUND AND PURPOSE: Currently available methods for determining aneurysm growth are not accurate enough. Therefore, we introduced a more intuitive and accurate 3D registration technology (3DRT) to judge the growth of aneurysms. MATERIALS AND METHODS: We developed an in-house technique for 3DRT and calculated its derivative parameters, voxel change rate (VCR), maximum growth vector (MGV), and parent artery coincidence (PAC). To verify the accuracy, growing aneurysms and stable aneurysms matching 1:3 were selected, and a 3DRT measurement was performed. We calculated the sensitivity, specificity, and accuracy of cases with VCR > 20%, MGV > 1 mm, and combined indicator of VCR > 20% + MGV >1 mm. In addition, we analyzed the cause of the poor registration effect, where the registration effect of PAC > 0.7 was considered acceptable. We also collected 24 consecutive aneurysms for agreement analysis of 2D manual measurement and 3DRT. RESULTS: Twenty-seven growing aneurysms and 81 stable aneurysms were included in the normal model group, and 88 aneurysms with good registration effect in the adjusted model group. For aneurysms with VCR > 20%, the sensitivity and the specificity were the highest at 81.48% and 91.35%, respectively, while in the adjusted model group, the sensitivity and the specificity increased to 94.44% and 94.29%, respectively. When using VCR > 20% as the growth metric, the AUC value in the normal and the adjusted model group was 0.856 and 0.947, respectively. The ICC between 2D manual measurements and the 3DRT was 0.95 (95%CI: 0.88-0.98), and the time spent between the two groups had a significant difference (10.96 min vs. 3.44 min, p<0.01, 95% CI, 6.49-8.53). CONCLUSIONS: A 3DRT can be used to determine the growth of the aneurysm more efficiently, intuitively, and accurately.
Subject(s)
Aneurysm, Ruptured , Intracranial Aneurysm , HumansABSTRACT
Objective: To investigate the influence of osteoarthritis (OA) at different sites and of different degrees on the prevalence of osteoporosis (OP) and lumbar bone mineral density (L-BMD) in men, and thereby to analyze the relationship between OA and OP. Methods: We collected information on the age, height, body mass, the course of pain, smoking status, exercise status, and history of hypertension and diabetes of 1206 male patients who received treatment for bone and joint pain at the Department of Osteoporosis and Rheumatology, West China Fourth Hospital, Sichuan University between January 2017 and December 2020. The patients' L-BMD was determined with dual-energy X-ray absorptiometry. The sites and the degrees of OA were evaluated by digital radiography and CT or MRI. χ 2 test was performed to compare the OP prevalence of different groups. Analysis of covariance was carried out to compare the L-BMD of different groups. Binary logistic regression was conducted to analyze the risk factors of OP. Results: OP prevalence of the OA group was significantly lower than that of the non-OA group ( P<0.05). OP prevalence of the lumbar vertebra OA group was significantly lower than that of the non-OA group ( P<0.05). In addition, OP prevalence of the mild OA group and moderate OA group was significantly lower than of the non-OA group ( P<0.05). The L-BMD of the OA group was significantly higher than that of the non-OA group ( P<0.05). In addition, there were significant differences in L-BMD between groups with OA at different sites ( P<0.05). Furthermore, the L-BMD of the lumbar vertebra OA group and the multi-site OA group was significantly higher than that of the non-OA group ( P<0.05). There were significant differences in L-BMD between groups with different degrees of OA ( P<0.05). Furthermore, the L-BMD of the mild OA group and moderate OA group was significantly higher than that of the non-OA group ( P<0.05). OA and exercise were found to be protective factors for OP (odds ratio [ OR]=0.715 and 0.625, 95% confidence interval [ CI]: 0.550-0.928 and 0.481-0.814, P<0.05). Age and BMI were found to be risk factors for OP in men ( OR=1.018 and 1.081, 95% CI: 1.008-1.028 and 1.042-1.122, P<0.05). Conclusion: Lumbar vertebra OA and mild and moderate OA decrease OP prevalence in men, while lumbar vertebra OA, multi-site OA, and mild and moderate OA increase L-BMD in men. OA and exercise decrease the occurrence of OP in men, while age and BMI increase the risk of OP in men.
Subject(s)
Osteoarthritis , Osteoporosis , Humans , Male , Osteoporosis/epidemiology , Bone Density , Osteoarthritis/epidemiology , Absorptiometry, Photon , Risk FactorsABSTRACT
The unidirectional rotation of chemically crosslinked light-driven molecular motors is shown to progressively shift the swelling equilibrium of hydrogels. The concentration of molecular motors and the initial strand density of the polymer network are key parameters to modulate the macroscopic contraction of the material, and both parameters can be tuned using polymer chains of different molecular weights. These findings led to the design of optimized hydrogels revealing a half-time contraction of approximately 5â min. Furthermore, under inhomogeneous stimulation, the local contraction event was exploited to design useful bending actuators with an energy output 400 times higher than for previously reported self-assembled systems involving rotary motors. In the present configuration, we measure that a single molecular motor can lift up loads of 200 times its own molecular weight.
ABSTRACT
Increasing seawater exposure is killing coastal trees globally, with expectations of accelerating mortality with rising sea levels. However, the impact of concomitant changes in atmospheric CO2 concentration, temperature, and vapor pressure deficit (VPD) on seawater-induced tree mortality is uncertain. We examined the mechanisms of seawater-induced mortality under varying climate scenarios using a photosynthetic gain and hydraulic cost optimization model validated against observations in a mature stand of Sitka spruce (Picea sitchensis) trees in the Pacific Northwest, USA, that were dying from recent seawater exposure. The simulations matched well with observations of photosynthesis, transpiration, nonstructural carbohydrates concentrations, leaf water potential, the percentage loss of xylem conductivity, and stand-level mortality rates. The simulations suggest that seawater-induced mortality could decrease by c. 16.7% with increasing atmospheric CO2 levels due to reduced risk of carbon starvation. Conversely, rising VPD could increase mortality by c. 5.6% because of increasing risk of hydraulic failure. Across all scenarios, seawater-induced mortality was driven by hydraulic failure in the first 2 yr after seawater exposure began, with carbon starvation becoming more important in subsequent years. Changing CO2 and climate appear unlikely to have a significant impact on coastal tree mortality under rising sea levels.
Subject(s)
Picea , Trees , Carbon , Carbon Dioxide/pharmacology , Seawater , Temperature , Vapor Pressure , WaterABSTRACT
Increasing sea levels associated with climate change threaten the survival of coastal forests, yet the mechanisms by which seawater exposure causes tree death remain poorly understood. Despite the potentially crucial role of nonstructural carbohydrate (NSC) reserves in tree survival, their dynamics in the process of death under seawater exposure are unknown. Here we monitored progressive tree mortality and associated NSC storage in Sitka-spruce (Picea sitchensis) trees dying under ecosystem-scale increases in seawater exposure in western Washington, USA. All trees exposed to seawater, because of monthly tidal intrusion, experienced declining crown foliage during the sampling period, and individuals with a lower percentage of live foliated crown (PLFC) died faster. Tree PLFC was strongly correlated with subsurface salinity and needle ion contents. Total NSC concentrations in trees declined remarkably with crown decline, and reached extremely low levels at tree death (2.4% and 1.6% in leaves and branches, respectively, and 0.4% in stems and roots). Starch in all tissues was almost completely consumed, while sugars remained at a homeostatic level in foliage. The decreasing NSC with closer proximity to death and near zero starch at death are evidences that carbon starvation occurred during Sitka-spruce mortality during seawater exposure. Our results highlight the importance of carbon storage as an indicator of tree mortality risks under seawater exposure.
Subject(s)
Carbohydrate Metabolism , Carbohydrates/analysis , Picea/chemistry , Picea/metabolism , Plant Leaves/chemistry , Plant Leaves/metabolism , Salt Stress , Seawater/adverse effects , Cause of Death , Salinity , WashingtonABSTRACT
Sea-level rise is one of the most critical challenges facing coastal ecosystems under climate change. Observations of elevated tree mortality in global coastal forests are increasing, but important knowledge gaps persist concerning the mechanism of salinity stress-induced nonhalophytic tree mortality. We monitored progressive mortality and associated gas exchange and hydraulic shifts in Sitka-spruce (Picea sitchensis) trees located within a salinity gradient under an ecosystem-scale change of seawater exposure in Washington State, USA. Percentage of live foliated crown (PLFC) decreased and tree mortality increased with increasing soil salinity during the study period. A strong reduction in gas exchange and xylem hydraulic conductivity (Ks) occurred during tree death, with an increase in the percentage loss of conductivity (PLC) and turgor loss point (πtlp). Hydraulic and osmotic shifts reflected that hydraulic function declined from seawater exposure, and dying trees were unable to support osmotic adjustment. Constrained gas exchange was strongly related to hydraulic damage at both stem and leaf levels. Significant correlations between foliar sodium (Na+) concentration and gas exchange and key hydraulic parameters (Ks, PLC, and πtlp) suggest that cellular injury related to the toxic effects of ion accumulation impacted the physiology of these dying trees. This study provides evidence of toxic effects on the cellular function that manifests in all aspects of plant functioning, leading to unfavourable osmotic and hydraulic conditions.